CONSTRUCTION OF HOMOGENEOUS MINIMAL 2-SPHERES IN COMPLEX GRASSMANNIANS
WHO对HPV疫苗质量、安全性及有效性指导原则
GUIDELINES TO ASSURE THE QUALITY, SAFETY AND EFFICACY OF RECOMBINANT HUMAN PAPILLOMA VIRUS VIRUS?LIKE PARTICLE V ACCINESHPV二、Special consideration section:在生产、非临床及临床中过程中的考虑因素:1、生产方面:VLP是复杂的生物产物,必须在不同水平下对其进行检测分析。
因而在其生产过程及质量控制上必须考虑以下几个因素:1)新的表达体系如杆状病毒(GSK),新的特殊要求。
但我们用的毕赤酵母,相对比较常见。
2)新佐剂(略)3)天然的L1蛋白是没有被糖基化修饰,目前的两种表达体系,在糖基化修饰上不存大问题,但要对糖基化及其位点进行分析。
4)L1衣壳蛋白亚单位的解聚与再聚,可能有利于纯化,并得到更稳定的VLP。
目前,我们的路线可能是不经解聚,直接纯化获得VLP。
个人感觉,到后期可以兵分两路,一路直接获得VLP,而另一路则将VLP解聚后,再进行纯化与重组。
5)纯化后的L1 VLP要进行生化及免疫上的鉴定,并测定L1的浓度、纯度及组聚情况。
6)如加入了防腐剂,应对其免疫性进行验证,并确认不会有负作用2、非临床方面:关键就是要证明其免疫原性,并能否产生免疫中和抗体。
3、临床方面:(略)三、生产指导(Part A. Guidelines on manufacturing)3.1定义definitions3.1.1国际名称和专有名称国际名称:重组人乳头瘤类病毒颗粒疫苗(基因型16 L1蛋白)3.1.2定义描述重组HPV VLP疫苗为无菌的液态疫苗,里面含纯化后由一种或多种HPV基因型重组的主要的衣壳蛋白,并与相应佐剂混合。
3.1.3国际标准品在此指导原则编写时,市场上暂无国际标准品提供。
但有相应试剂在实验室水平上,在进行注射后进行生物效价方面的评价如抗体滴度和病毒DNA检测。
同义词替换(剑八)
同义词替换（剑八）TEST1:1.agree = concur = go along with = fall in with = go with v.同意2.sceptic and advocate = different attitude 不同的看法sceptic : n.怀疑者advocate = supporter : n.拥护者3.significance = impressive = meaning = sense n.重要性4.meditation : the practice of emptying your mind of thoughts and feelings, in order to relax completely or for religious reasons n.冥想，沉思5.parapsychology : the scientific study of mysterious abilities that some people claim to have, such as knowing what will happen in the future n.通灵学6. environment = condition = light, sound, warmth = situation = circumstance n.环境7. alter = change = revise = make changes v. 改变8. trial = experiment = test n.实验9. success rate = positive result = achievement = progress = breakthrough = accomplishment n.成就10. pick out = identify = recognize = know = tell v.认出，识别11. limit = minimize = maximum = the most = ceiling = cut-off pointv.限制12. different = individual = not like = vary = not the same = contrast with = diverse adj.独特的13. invention = device = creation = innovation n.发明，装置14. cold temperature = freezing weather = chilly = frosty = wintry = cold snap adj.寒冷的15. farming = agriculture n.农业16. simultaneous = at the same time = together = at once = at one time adj.同时的17. uniform = equal = homogeneous adj.均衡的18. devise = formulate = invent = create = come up with = make up = conceive = coin = dream up v.创造19. civil = municipal = metropolitan adj.城市的20. divide = split = separate = break up = break down = take apart = take something to piece v. 分开21. new = revolutionary = original = innovation = fresh = novel = be in its infancyadj.新的，革命的22. create = introduce = invent = make sth. do sth. = be the cause = lead to sth. v..发明23. organize = co-ordinate = arrange = set out = put something in order = line up v.组织，使协调24. public event = communal activity 公众、社交活动25. aviation disaster = sky accident = air crash 空难26. prompt = result in = lead to = make somebody do something = cause somebody to do something = lead somebody to do something = motivate = induce somebody to do something v. 导致27. resemble = like = similar = alike = much the same = comparable v.类似28. oversimplify = incomplete = simplistic = generalize = see things in black and white adj. 过于简化的，不完整的29. altitude = from…meters above th e ground = height = how high = level n.高度30. zone = airspace = region = area = district = quarter = block = suburb n.区域31. weather = meteorological = climate = condition n.气候32. categorize = class / type = sort = classify = be grouped = grade v.分类33. create = establish = invent = start up = open = set up = found = inception v.创建34. beacon and flashing = light = beam n.灯光beacon : a light that is put somewhere to warn or guide people, ships, vehicles, or aircraftflashing : a bright light that shines for a short time and then stops shining 35. improve = develop = evolve = get better = catch up = pick up = things are looking up v.发展，进化36. aircraft = plane = by air n.飞机37. average-sized = medium-sized adj. 中等的38. city = metropolitan = urban = town = village = civic = municipal = downtown n.城市39. pendulum : a long metal stick with a weight at the bottom that swings regularly from side to side to control the working of a clock n.钟摆40. coincidental : happening completely by chance without being planned adj.巧合的41. disobey : to refuse to do what someone with authority tells you to do, or refuse to obey a rule or law v.不服从TEST 21. drastically : extreme and sudden adv.彻底地2. carry out : 执行subject to : 使服从3. remain = stay = keep = continue to be = still v.保持4. detect = inspect = examine = notice = spot = become aware / conscious = note = conserve = perceive v.检查5. fault = flaw = defect = trouble = bug = virus = be something wrong with = be something matter with n.缺陷，缺点6. enough = sufficient = adequate = cover = meet somebody’s need adj.足够的7. main = largely = principal = chief = major = key = primary = prime = predominant = core adj.主要的:8. documentation = written account = evidence = proof n.证明9. shift = switch = transfer = move = jerk v.转换10. consistent = lasting = stay the same = constant = unchanging adj.持续的11. drought = no rain at all = dry = dusty adj.干旱的12. period = cycle = era = age n.年代13. random = arbitrary = at random adj.随机的14. molten = hot = heat = boiling / boiling hot = scalding / scalding hot adj.熔化的15. intense = strong = passionate = powerful = deep adj.强烈的16. discover = explore = find / unearth = turn upv.开发，发现17. pattern = trade / commodity = business n.贸易18. relate to= associate with = link to / connect to = identify with 联系19. feeling = emotional response / sensory = a sense of = passion n. 感觉20. unappreciated = undervalued adj.低估的21. difficult = elusive = hard / tough = easier said than doneadj.困难的，难懂的22. study = research = analyse = do/conduct research v.研究23. smell = odour = scent n.气味24. interpretation = be considered to be = understanding = readingn.理解25. define = distinguish = tell the difference v.使明确26. damage = impair = break = do/cause damage = scratch v.损害27. realize = consciously consider = occur to = become aware = sink in = strike = hit = wake up to the fact that v.想到28. reveal = show = demonstrate = let somebody see = present = expose = let somebody take a look v.显示29. to be defined = unanswered 无答案的30. husbands and wives = marriage partner / spouse = couple = newlyweds夫妇31. linguistic = language n.语言32. describe = name = express = give a description of = talk about = write about = give an account of = tell of v.描述33. lack = do not exist = not enough = scarce = inadequate = insufficient = in short supply v.缺乏的34. do not smell = odorless 没有气味的35. regard as = consider to 把。
2021 年度诺贝尔化学奖：大道至简
大 学 化 学Univ. Chem. 2022, 37 (1), 2112014 (1 of 5)收稿：2021-12-07；录用：2021-12-17；网络发表：2021-12-22*通讯作者，Email:******************.cn基金资助：国家自然科学基金(21825108)•今日化学• doi: 10.3866/PKU.DXHX202112014 2021年度诺贝尔化学奖：大道至简冯向青1,2，杜海峰1,2,*1中国科学院化学研究所分子识别与功能院重点实验室，北京 1001902中国科学院大学，北京 100049摘要：有机小分子成为继酶和金属催化剂之后发展的一类新型催化剂，被称为第三类催化。
有机小分子催化作为一种精确的分子构建新工具，对手性新药研发产生了巨大影响，在药物、农药、化工、材料等领域都得到了广泛的应用。
2021年的诺贝尔化学奖授予了德国化学家本杰明·利斯特和美国化学家大卫·迈克米伦，以表彰他们在这一领域做出的开创性重要贡献。
本文简述了手性现象和不对称催化，有机小分子催化的发展历程及其催化优势和未来前景。
关键词：手性；不对称催化；有机小分子催化；诺贝尔化学奖中图分类号：G64；O6The 2021 Nobel Prize in Chemistry: The Simpler the BetterXiangqing Feng 1,2, Haifeng Du 1,2,*1 CAS Key Laboratory of Molecular Recognition and Function, Institute for Chemistry, Chinese Academy of Sciences, Beijing 100190, China.2 University of Chinese Academy of Sciences, Beijing 100049, China.Abstract: Organic molecules have become one novel type of catalysts developed after enzymes and metal catalysts, which are named as organocalysis, the third type of catalysis. As a new tool toward the precise construction of molecules, organocatalysis has a huge impact on the development of chiral new drugs, which has been used in the fields of pharmacy, pesticides, chemicals, materials, and so on. The 2021 Nobel Prize in Chemistry was awarded to German chemist Benjamin List and American chemist David W. C. MacMillan for their pioneering and important contributions to this field. This article will briefly describe chirality and asymmetric catalysis, especially, the history of organocatalysis development, its advantages and future prospects.Key Words: Chirality; Asymmetric catalysis; Organic small molecule catalysis; Nobel prize in chemistry1 2021年诺贝尔化学奖获得者简介2021年10月6日，长期被戏称为“理综奖”的诺贝尔化学奖被授予“对于有机小分子不对称催化[1]的重要贡献”的两位化学家，分别是德国化学家本杰明∙利斯特(Benjamin List)和美国化学家戴维∙麦克米伦(David W. C. MacMillan)。
在胶原上用EDC和NHS固定肝素
TISSUE ENGINEERINGVolume 10, Number 9/10, 2004©Mary Ann Liebert, Inc.Modulation of Angiogenic Potential of Collagen Matrices by Covalent Incorporation of Heparin and Loading with VascularEndothelial Growth FactorG.C.M. STEFFENS, Ph.D.,1C. YAO, M.D.,1,2P. PRÉVEL, M.D.,1,2M. MARKOWICZ, M.D.,2P. SCHENCK, Ph.D.,3E.M. NOAH, Ph.D., M.D.,2and N. PALLUA, Ph.D., M.D.2ABSTRACTOne of the prominent shortcomings of matrices for tissue engineering is their poor ability to sup-port angiogenesis. We report here on experiments to enhance the angiogenic properties of collagen matrices. Our aim is to achieve this goal by covalently incorporating heparin into collagen matri-ces and by physically immobilizing angiogenic vascular endothelial growth factor (VEGF) to the heparin. The immobilization of heparin was performed with 1-ethyl-3-(3-dimethylaminopropyl)-car-bodiimide (EDC) and N -hydroxysuccinimide (NHS). Carboxyl groups on the heparin are activated to succinimidyl esters, which react with amino functions on the collagen to zero length cross-links.This modification leads—in addition to the incorporation of heparin—to gross changes in in vitro degradation behavior and water-binding capacity. As a first approach to testing angiogenic capa-bilities, endothelial cells were exposed to nonmodified and heparinized collagen matrices. This ex-posure leads to an increase in endothelial cell proliferation. The increase can be further enhanced by loading the (heparinized) collagen matrices with VEGF. Evaluation of the angiogenic potential of heparinized matrices was further investigated by exposing them to the chorioallantoic membrane of chicken embryos and to the subcutaneous tissue of rats. Both approaches show that heparinized matrices have substantially increased angiogenic potential. In particular, the loading of heparinized matrices with VEGF invokes a further increase in angiogenic potential. It is apparent that the phys-ical binding of VEGF to heparin allows for a release that is beneficial to angiogenesis. By varying the heparin and EDC/NHS concentrations during the modification process and by varying the load-ing with VEGF, the angiogenic potential as well as the degradation behavior can be adapted to ob-tain matrices that fulfill specific angiogenic requirements in the field of tissue engineering.1502INTRODUCTIONENHANCEMENT OF THE ANGIOGENIC POTENTIALof im-plantable (bio)materials has received much atten-tion.1Because the angiogenic potential of most synthetic and natural materials is insufficient, many attempts havebeen made to enhance angiogenic potential either by changing the physicochemical parameters or by supple-mentation with angiogenic factors. Angiogenesis is the sprouting of new capillaries from preexisting vasculature and represents a complex multistep process that requires the adhesion, proliferation, and differentiation of endo-1Institute of Biochemistry 2Department of Plastic, Hand, and Burn Surgery, RWTH Aachen University, Aachen, Germany.3Dr. Suwelack Skin and Health Care, Billerbeck, Germany.thelial cells. Endothelial cell growth, proliferation, and differentiation depend on recruitment of specific integrins (a v 3) on the cell surface. These integrins must bind to their proper ligands in order to initiate distinct second-messenger pathways that finally lead to transformation into the angiogenic phenotype of endothelial cells.2In the present study, the angiogenic properties of ma-trices made of collagen are investigated. Collagen repre-sents a suitable substrate for cell attachment: it is bio-compatible and degrades into harmless products that are metabolized or excreted.3Collagen can be formed into three-dimensional matrices that are being applied as tis-sue substitutes or scaffolds for tissue regeneration.4The properties of collagen can be modified in many different ways.5,6Several authors claim that the covalent incorporation of glycosaminoglycans modifies the prop-erties of collagenous material. Thus Silver et al .7Wissink et al .,8,9and Tsai et al .10covalently linked heparin to col-lagenous films whereas Yannas and Burke 11and Pieper et al .12,13covalently incorporated chondroitin sulfate into collagen matrices. These modifications had positive ef-fects on in vivo blood compatibility and the proliferation of endothelial cells, respectively. Loading of heparinized collagen films with basic fibroblast growth factor (bFGF)in general leads to even stronger effects on the prolifer-ation of endothelial cells.14In our study we investigated the effects of the cova-lent incorporation of heparin into three-dimensional col-lagen matrices by 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide/N -hydroxysuccinimide (EDC/NHS). More-over, we report on the effects exerted by loading vascu-lar endothelial growth factor (VEGF) into these heparinized collagen matrices. Together these modifica-tions lead to a variety of collagen matrices in which the following parameters can be modulated: (1) angiogenic potential, (2) resistance to in vitro degradation with col-lagenase, and (3) moisture-binding capacity. These prop-erties may thus be modulated in order to adapt the col-lagenous matrices to specific requirements in the field of tissue engineering.MATERIALS AND METHODSCollagen matricesCollagen matrices were produced by Dr. Suwelack Skin & Health Care (Billerbeck, Germany). The matri-ces were obtained through lyophilization of collagen sus-pensions containing primarily collagen type I. The porous structure is nondirected and the pore sizes vary from 15to 25 m; the overall porosity amounts to ϳ98%.The collagen matrices were cut into cubes of either 5ϫ5ϫ5 mm (3.8–4.2 mg) or 10ϫ10ϫ10 mm (22–24 mg) and into circular specimens (diameter, 10mm; thickness, 2 and 5 mm).HEPARIN/VEGF-MODIFIED ANGIOGENIC POTENTIAL Heparin immobilizationHeparin immobilization was performed essentially as described in Hinrichs e t al .15and Wissink e t al .8Car-boxylic acid groups of heparin (Hep-COOH) were acti-vated with EDC and NHS. Heparin (sodium salt, 170 USP units/mg), EDC, and NHS were purchased from Sigma-Aldrich (St. Louis, MO). A typical modification experi-ment was performed as follows: 1 mg of heparin was ac-tivated with 1 mg of EDC per 0.6 mg of NHS in 500 L of 0.05 M 2-morpholinoethanesulfonic acid (MES) buffer (pH 5.6) for 10 min at 37°C, cubic collagen matrices (size, 5ϫ5ϫ5 mm) were immersed into the reagent so-lution, and the solution was evacuated to remove air from the matrices. After a reaction period of 4 h at 37°C, un-der gentle shaking, the heparinized collagen sponges were washed with 0.1 M Na 2HPO 4(pH 9.2) (2 h), 4 M NaCl (four times in 24 h) and deionized water (five times in 24 h). Finally, modified sponges were frozen at Ϫ80°C overnight (16 h), lyophilized, and stored at room tem-perature. Collagen matrices according to these parame-ters are designated H1E1 (1 mg of heparin and 1 mg of EDC per 0.6 mg of NHS per 500 L). The modification parameter H1E2 refers to 1 mg of heparin and 2 mg of EDC per 1.2 mg of NHS, and H0E0 refers to a collagen matrix that underwent all the procedures, except that no heparin and EDC/NHS were added.Determination of immobilized heparinThe amount of immobilized heparin was determined by toluidine blue assay.15,16Cubic collagen matrices (size, 5ϫ5ϫ5 mm; weight, 3.8–4.2 mg) were incu-bated with 5 mL of an aqueous solution of toluidine blue (0.1 M HCl, NaCl [2 mg/mL], and toluidine blue zinc chloride double salt, [0.4 mg/mL]; Sigma) for 4 h at room temperature, resulting in complexation of toluidine blue with heparin. Specimens were then washed five times with distilled water (10 mL/sample) in 24 h. Subse-quently, toluidine blue complexed to heparin was solu-bilized with 5 mL of a 1:4 (v/v) mixture of 0.1 M NaOH and ethanol. Absorbance of the resulting solution was de-termined at 530 nm after 1:5 dilution with the sodium hydroxide–ethanol solution. Standard curves were ob-tained according to the heparin solution assay protocol of Hinrichs et al .15Determination of free amino groups in heparinized collagen matricesThe residual number of free primary amino groups af-ter heparin immobilization was determined with trini-trobenzene sulfonic acid (TNBS). Collagen specimens were immersed in a mixture of 1 mL of 4 wt% NaHCO 3(pH 9) and 1 mL of 0.5% TNBS, and incubated overnight at 40°C. To this 3 mL of 6 M HCl was added and the so-lution was incubated at 60°C for another 1.5 h. After cool-1503ing to room temperature, 20 mL of anhydrous ethyl etherwas added for extraction of the excess TNBS and TNP-␣-amino acids17; this procedure was repeated at least five times. After 1:10 dilution with distilled water the ab-sorbance of the resulting solution was determined at 345nm. A control was prepared applying the same procedurewith the exception that HCl was added before the addi-tion of TNBS. The number of amino groups per 1000amino acids was obtained with the following formula: Free amino groupsϭ(absorbance at 345 nm)(0.05 L)MW/(1.46ϫ10,000 L/mol и cm)bx where MW is the molecular mass of the collagen (g/mol), 1.46ϫ10,000 L/mol иcm is the molar absorptivity of TNP-lysine, b is the cell path length (cm), and x is the sample weight (g).17In vitro degradation with collagenaseThe degree of degradation of heparinized collagensponges was determined by measuring sample weightsbefore and after degradation by collagenase fromClostridium histolyticum(type I; Worthington Biochem-icals, Lakewood, NJ). The original weights of specimens were determined after lyophilization. Modified and non-modified matrices were immersed in a solution contain-ing 40 or 200 units of collagenase in 1 mL of (PBS) buffer (pH 7.2) and incubated at 37°C under gentle shaking for the desired period of time. Degradation was stopped at specified time intervals by addition of 0.2 mL of a 0.25 M EDTA solution and the samples were cooled on ice for 10 min. Subsequently, the samples were washed with 5 mL of PBS buffer (pH 7.2, three times for 15 min each) and demineralized water (three times for 15 min each), frozen at Ϫ80°C (overnight), and lyophilized. After lyophilization, the weights of the residual samples were determined and the percentage of degradation at the spec-ified time interval t is calculated as follows: Degradation (%)ϭ(original weight Ϫ residualweight at time t)/(original weight/100) Moisture uptakeFor the analysis of moisture uptake the initial dryweights (W dry) of collagen matrix specimens (size, 5ϫ5ϫ5 mm; weight, 3.8–4.2 mg) were determined. Afterimmersion in PBS for 2 h at 37°C the weights of thewet specimens (W wet) were determined. Before theweighing process the wet matrices were brought intocontact with a piece of filter paper to remove looselybound moisture. Moisture binding was calculated ac-cording to the formulaMoisture uptake (mg/mg)ϭ(W wetϪW dry)ᎏᎏW drySTEFFENS ET AL.Exposure to endothelial cellsEndothelial cells were isolated from human umbilicalcords (human umbilical vascular endothelial cells[HUVECs] and cultivated in endothelial cell basalmedium (ECBM). For exposure experiments the secondpassage was used.In each well of a 6-well plate 100,000 HUVECs wereallowed to adhere for 1 day in 2 mL of ECBM (Cell-Systems, St. Katharinen, Germany). On day 2 collagenmatrices (cubes, 10ϫ10ϫ10 mm in size) modified ac-cording to the specified parameters were placed in thewells and the wells were filled with 2 mL of mediumwithout VEGF. Some of the matrices were loaded witha sterile solution (20 L) containing 100 ng ofrhVEGF165(R&D Systems, Minneapolis, MN). For ref-erence, one well of each plate was filled with ECBMonly. The cells were allowed to proliferate for 5 days,and on day 7 the matrices were removed and theHUVECs were trypsinized with EDTA–trypsin. Cellswere counted microscopically in a Neubauer chamber.To highlight changes in proliferation, cell numbers pres-ent on day 1 were subtracted from the observed numbersof cells.Chorioallantoic membrane assayFertilized chicken eggs were obtained from Bücher-hof (Horbach-Aachen, Germany). The chorioallantoicmembrane assay (CAM assay) was performed essen-tially as described in Zwadlo-Klarwasser e t al.18He-parinized and cross-linked collagen matrices were pre-pared according to the modification proceduresdescribed above and sterilized by immersion in 70%ethanol for 24 h. Sub-sequently they were equilibratedwith either PBS or serum-free ECBM under sterile con-ditions. In selected experiments 300 ng of rhVEGF165(R&D Systems) was loaded onto modified and non-modified matrices before exposure to chorioallantoicmembrane. Circular specimens of the various collagenmatrices (diameter, 12 mm; thickness, 2 mm) werecarefully placed on the chorioallantoic membrane andthe eggs were further incubated at 37°C for 7 days. Atthe end of this period, the chorioallantoic membraneswere either fixed in situ with 4% buffered formalin, ex-cised, and mounted on a slide, or the collagen speci-mens were dissected together with the surroundinggranulation tissue and processed for histological char-acterization.Quantitation of capillaries was carried out by countingthem at 50-fold magnification in three nonoverlappingareas. The average number of small vessels (diametersmaller than 20–40 m) in the defined areas was takenas an index for angiogenic potential after subtraction ofthe number of capillaries counted in the absence of anymatrix.1504Animal model experimentsCollagen matrices (diameter, 10 mm; thickness, 5 mm)modified according to the parameters described abovewere implanted in four dorsal subcutaneous pockets ofLewis rats, each implant 1 cm from the skin incision andwith 4 cm between them. The variously modified colla-gen matrices were implanted in animals either loadedwith 300 ng of recombinant rat VEGF 165or nonloaded.After 14 days of implantation the animals were killed andthe matrices were explanted. Explants were extensivelywashed with 1 mL of water for about 24 h and the hemeprotein content was determined spectrophotometrically atthe Soret band (absorbance, 410 nm).RESULTSIn an attempt to increase the angiogenic potential of collagen matrices by covalent incorporation of heparin and subsequent physical immobilization of VEGF, a se-ries of experiments was performed to evaluate heparin content after exposure of collagen matrices to heparin activated with 1-ethyl-3-(3-dimethylamino-propyl)-car-bodiimide (EDC)/N -hydroxysuccinimide (NHS). The ex-tent of heparin immobilization was determined with o -toluidine blue; this dye specifically binds to carboxyl groups.15After removal of excess dye by extensive wash-ing with water, the bound dye molecules were released by hydrolysis with NaOH and ethanol followed by quan-tification by absorption spectrophotometry.Figure 1 gives an overview of a number of properties of collagen matrices prepared according to a restrictedset of modification parameters (the modification param-eters are described in detail in Materials and Methods).In brief, the designation H1E0.5 refers to 1 mg of hep-HEPARIN/VEGF-MODIFIED ANGIOGENIC POTENTIAL arin and 0.5 mg of EDC (0.3 mg of NHS) being present in 500 L of the activation solution.The results of Fig. 1 show that the amount of heparinimmobilization clearly correlates with the concentrationof cross-linking reagents EDC and NHS in the solutionfor activating the carboxyl groups of heparin. The resultsobtained with the modification parameters H1E0 showthat adsorptive binding of heparin is negligible, appar-ently all physically bound heparin is removed during theextensive washing procedure. The amounts of immobi-lized heparin vary from 7 to about 40 g of heparin permilligram of collagen. It appears that with 2 mg of EDCa plateau is reached, and higher concentrations ofEDC/NHS do not lead to higher heparin-binding densi-ties.In addition to the covalent immobilization of the hep-arin to collagen, an additional cross-linking of collagen is likely to occur.14,19This additional cross-linking sub-stantially affects the resistance against degradation by collagenase.5,14We therefore subjected the same set of collagen matrices to in vitro degradation experiments.The results of these experiments are also shown in Fig.1. Whereas matrices modified at relatively low EDC con-centrations are substantially degraded, degradation per-centages with 40 units of collagenase for 2 h at 37°C vary from 60 to 30%. Matrices modified with EDC concen-trations equal to or greater than 1 mg of EDC per 500-L reaction volume clearly withstand degradation and the corresponding degradation percentages are on the or-der of 10% or less. A sharp increase in resistance againstdegradation was observed by increasing the EDC con-centration from 0.2 to 1.0%.To better understand the binding and cross-linking mechanisms we also investigated the number of available free ␣-amino groups (i.e., the number of available lysines and hydroxylysines) in the modified and non-modified1505FIG. 1.Extent of heparin immobilization and in vitro degradation as a function of increasing EDC/NHS-to-heparin weight ra-tios. Collagen matrices were modified and designated according to parameters specified in Materials and Methods. Degradation was carried out with 40 units of collagenase in 1 mL of PBS buffer for 2 h at 37°C. The columns show the mean values, and the error bars represent the corresponding standard deviations (n ϭ5).collagen matrices. Available amino groups were deter-mined with trinitrobenzenesulfonic acid (TNBS).17These results are given in Fig. 2. Within the set of modification parameters a continuous decrease of the number in free amino groups is observed, surprisingly, a sharp decrease of the number in free amino groups—as might be ex-pected from the degradation experiments—is not ob-served. The number of 35 free amino groups in non mod-ified collagen (H0E0) nicely corresponds to the number of lysines and hydroxylysines as deduced from the DNA-derived amino acid composition and amino acid analysis investigations.5The number of 21 free amino groups in the collagen matrix H1E4 demonstrates that in this case about 14 lysines and hydroxylysines per 1000 amino acids of collagen are involved in heparin binding and cross-linking.Another property of the modified collagen matrices that may be affected by heparin binding and/or additional cross-linking is the capability to take up moisture. The effects of the modification procedures on moisture up-take can also be deduced from Fig. 2: the moisture-bind-ing capacity of collagen matrices H1E2, H1E3, and H1E4 is almost twice as high as the moisture uptake of non-modified matrices. Above a concentration of 2 mg of EDC per 500-L reaction volume the moisture uptake seems to have reached a plateau.The angiogenic potential of the modified matrices was investigated by three different approaches. The first ap-proach focused on the change in proliferation rates of en-dothelial cells when they contact nonmodified and he-parinized collagen matrices. Figure 3 shows the results of a series of cell culture experiments with human um-bilical endothelial cells exposed to nonmodified (H0E0)STEFFENS ET AL. and heparinized (H1E0.2–H1E2) collagen matrices. To test the possible beneficial effect of loading VEGF onto these matrices, matrices were loaded with 50 ng of VEGF as indicated. The results clearly demonstrate that both the modification and the loading with VEGF have a sub-stantial impact on proliferation.The proliferation rate increases with increasing EDC/NHS concentrations and reaches a plateau at a con-centration of 1 mg of EDC per 500-L reaction volume. The additional effect exerted by loading with VEGF is clearly more prominent for collagen matrices modified by incorporation of heparin. The greatest effect is ob-served for H1E1 collagen matrices loaded with 50 ng of VEGF.As a second approach to evaluating the angiogenic po-tential of heparinized collagen matrices, we exposed the chorioallantoic membrane of chicken embryo18,20to non-modified and modified collagen matrices. Angiogenic potential was deduced from the density of microvessels (number per area) induced by the nonmodified and mod-ified collagen matrices. Microvessel densities already ob-served in the absence of any collagen matrix (control) were subtracted from the number of capillaries induced in the presence of the modified matrices. Figure 4 shows the number of observed capillaries and the increase in capillary density. The induction of angiogenesis increases with larger EDC-to-heparin ratios.In another set of experiments nonmodified (H0E0) and heparinized (H1E1) matrices were loaded with VEGF be-fore being exposed to the chorioallantoic membrane. Fig-ure 5 shows the observed number of capillaries and the calculated increases induced by loading H0E0 and H1E1 matrices with VEGF.1506FIG. 2.Free amino groups per 1000 amino acids and moisture uptake as a function of increasing EDC/NHS-to-heparin weight ratios. Collagen matrices were modified and designated according to parameters specified in Materials and Methods. Free amino groups were determined with trinitrobenzenesulfonic acid (TNBS). Columns show the mean values, and error bars represent the corresponding standard deviations (nϭ5).The effects on angiogenic potential were also investi-gated in animal model experiments with rats. Nonmodi-fied and heparinized specimens were either loaded with 300 ng of VEGF or nonloaded and subcutaneously im-planted in pockets prepared on the back of Lewis rats.The specimens were explanted after 14 days and evalu-ated for their heme protein contents. These experiments were restricted to nonmodified (H0E0) and collagen ma-trices modified according to the parameters H1E1.Figure 6 shows the hemoglobin contents of the corre-sponding explants. Heparinized matrices demonstrated substantially increased vascularization, which could beHEPARIN/VEGF-MODIFIED ANGIOGENIC POTENTIALfurther enhanced by loading the heparinized matrices with VEGF. In the case of nonmodified collagen matrix the additional beneficial effect of VEGF loading remains relatively small.DISCUSSIONThe covalent incorporation of heparin into collagen matrices has been investigated in order to develop colla-gen matrices with enhanced angiogenic potential. Figures 1 and 2 compile a series of biochemical and biophysical1507FIG. 3.Induction of proliferation of human umbilical vein endothelial cells (HUVECs) by exposure to nonmodified (H0E0)and modified (H1E0.2–H1E2) collagen matrices. Matrices were either nonloaded or loaded with 50 ng of rhVEGF 165. The ex-periments were carried out as described in Materials and Methods. The increase in the number of cells was obtained by sub-tracting the number of cells at the start of the experiment (100,000). Columns show the mean values, and error bars represent the corresponding standard deviations (n ϭ3).FIG. 4.Angiogenic effect exerted by implantation of collagen matrices into the chorioallantoic membrane of chicken embryos.Collagen matrices were modified and designated according to parameters specified in Materials and Methods. Capillaries were counted as described in Materials and Methods. The increase in number of capillaries was obtained by subtracting the number of capillaries in the control experiments. Columns show the mean values, and error bars represent the corresponding standard deviations (n ϭ5).characterizations of modified matrices. The immobiliza-tion of heparin almost linearly increases with the con-centration of EDC/NHS in the reaction mixture. Values vary from 10 to about 40 g/mg of collagen and appear to reach a maximum at concentrations in excess of 1 mg of EDC per 500-L reaction volume. Resistance to in vitro degradation with collagenase sharply increases at EDC concentrations in excess of 0.2 mg of EDC per 500-L reaction volume. We explain this observation as fol-lows: at relatively low concentrations of heparin, most of the EDC/NHS is used for the activation of carboxyl groups on the heparin molecules, and thus fewer EDC/NHS molecules are available for the additional cross-linking of collagen fibrils. When the EDC/NHS concentration exceeds 0.2 mg/500-L reaction volume,more cross-linking molecules remain available for addi-tional cross-linking of collagen fibrils. This process leads to a sharp decrease in the degradation percentages. In-creasing heparin-to-EDC ratios lead to both lower hep-arin incorporation and lower additional cross-linking;thus H2E1 incorporates less heparin and is degraded more rapidly (data not shown).The number of free amino groups consistently decreases with increasing EDC/NHS concentrations, the largest re-duction of free amino groups being observed on increasing the EDC/NHS concentration from 3 to 4 mg/500-L reac-tion mixture. This may be explained by the fact that in this case only a small amount of EDC/NHS is consumed for the activation of heparin, and thus all the extra EDC/NHS molecules are available for cross-linking of collagen.The evaluation of angiogenic potential by three indepen-dent approaches shows that the heparinized matrices induce greater angiogenic effects. The exposure of HUVECs to he-parinized matrices clearly leads to higher proliferation rates,and loading of these matrices with VEGF further increases the proliferation rates. The most prominent effect was ob-served with collagen matrices modified according to the pa-rameters H1E1 and loaded with VEGF (Fig. 3).Similar effects were observed by exposing chicken em-bryo chorioallantoic membrane to heparinized collagen matrices. Again H1E1 collagen matrices loaded with VEGF induced significantly greater angiogenic effects (Figs. 4 and 5).Subcutaneous implantation of nonmodified and he-1508FIG. 5.Angiogenic effects of loading 100 ng of rhVEGF 165into nonmodified (H0E0) and heparinized (H1E1) collagen ma-trices. Angiogenic effects were evaluated by implanting collagen matrices—either loaded or nonloaded—into chicken embryo chorioallantoic membranes. Capillaries were counted as described in Materials and Methods. The increase in the number of cap-illaries was obtained by subtracting the number of capillaries in the control experiments. Columns show the mean values, and error bars represent the corresponding standard deviations (n ϭ5).FIG. 6.Angiogenic potential of modified and nonmodified collagen matrices as evaluated by subcutaneous implantation in rats. Collagen matrices were modified and designated accord-ing to parameters specified in Materials and Methods. Matrices were either loaded with 300 ng of rhVEGF 165or nonloaded.Angiogenesis was evaluated by determining the hemoglobin content of matrices, which were explanted after 14 days.Columns show the mean values, and error bars represent the corresponding standard deviations (n ϭ2).parinized matrices in animal model experiments allowed for alternative in vivo evaluation with closer proximity to the final clinical indication. Angiogenic potential was evaluated by determining the hemoglobin absorbance of wash solutions of each specimen, explanted after 14 days.As evaluated by this approach, heparinized matrix H1E1loaded with VEGF again showed the greatest increases in angiogenic effect.Because the applied approaches do not allow state-ments on the quality of the vasculature within the im-plants we are currently evaluating explants from the in vivo experiments by immunohistochemistry. Further-more, it would be worth investigating to what extent and by which parameters the additional cross-linking is in-fluencing the angiogenic outcome of the modifications described in this article.ACKNOWLEDGMENTSThis work was supported by grant 0312692 from the Bundesministerium für Bildung und Forschung (Berlin,Germany) to Dr. Suwelack Skin and Health Care AG (Billerbeck, Germany) and by grant TV B 47 from the Interdisciplinary Centre for Clinical Research Biomat of the Medical Faculty of RWTH Aachen University (Aachen, Germany).REFERENCES1.Nomi, M., Atala, A., Coppi, P.D., and Soker, S. Principles of neovascularization for tissue engineering. Mol. Aspects Med. 23,463, 2002.2.Hall, H., Baechi, T., and Hubbell, J.A. Molecular proper-ties of fibrin-based matrices for promotion of angiogene-sis in vitro . Microvasc. Res. 62,315, 2001.3.Friess, W. Collagen: Biomaterial for drug delivery. Eur. J.Pharm. Biopharm. 45,113, 1998.4.Yannas, I.V., Burke, J.F., Orgill, D.P., and Skrabut, E.M.Wound tissue can utilize a polymeric template to synthe-size a functional extension of skin. Science 215,174, 1982.5.Zeeman, R., Cross-linking of collagen-based materials [Ph.D. thesis]. University of Twente, Enschede, The Netherlands, 1998.6.Zeeman, R., Dijkstra, P.J., van Wachem, P.B., van Luyn,M.J., Hendriks, M., Cahalan, P.T., and Feijen, J. Succes-sive epoxy and carbodiimide cross-linking of dermal sheep collagen. Biomaterials 20,921, 1999.7.Silver, F.H., Yannas, I.V., and Salzman, E.W. Glycosami-noglycan inhibition of collagen induced platelet aggrega-tion. Thromb. Res. 13,267, 1978.8.Wissink, M.J., Beernink, R., Pieper, J.S., Poot, A.A., En-gbers, G.H., Beugeling, T., van Aken, W.G., and Feijen, J.Immobilization of heparin to EDC/NHS-crosslinked colla-gen: Characterization and in vitro evaluation. Biomaterials 22,151, 2001.9.Wissink, M.J., Beernink, R., Poot, A.A., Engbers, G.H.,Beugeling, T., van Aken, W.G., and Feijen, J. ImprovedHEPARIN/VEGF-MODIFIED ANGIOGENIC POTENTIAL endothelialization of vascular grafts by local release of growth factor from heparinized collagen matrices. J. Con-trol. Release 64,103, 2000.10.Tsai, C.C., Chang, Y., Sung, H.W., Hsu, J.C., and Chen,C.N. Effects of heparin immobilization on the surface char-acteristics of a biological tissue fixed with a naturally oc-curring crosslinking agent (genipin): An in vitro study. Bio-materials 22,523, 2001.11.Yannas, I.V., and Burke, J.F. Design of an artificial skin. I.Basic design principles. J. Biomed. Mater. Res. 14,65, 1980.12.Pieper, J .S., van Wachem, P.B., van Luyn, M.J.A.,Brouwer, L.A., Hafmans, T., Veerkamp, J.H., and van Kup-pevelt, T.H. Attachment of glycosaminoglycans to col-lagenous matrices modulates the tissue response in rats.Biomaterials 21,1689, 2000.13.Pieper, J.S., Hafmans, T., Veerkamp, J.H., and van Kup-pevelt, T.H. Development of tailor-made collagen–glycos-aminoglycan matrices: EDC/NHS crosslinking, and ultra-structural aspects. Biomaterials 21,581, 2000.14.Wissink, M.J., van Luyn, M.J., Beernink, R., Dijk, F., Poot,A.A., Engbers, G.H., Beugeling, T., van Aken, W.G., and Feijen, J. Endothelial cell seeding on crosslinked collagen:Effects of crosslinking on endothelial cell proliferation and functional parameters. Thromb. Haemost. 84,325, 2000.15.Hinrichs, W.L.J., ten Hoopen, H.W.M., Wissink, M.J.B.,Engbers, G.H.M., and Feijen, J. Design of a new type of coating for the controlled release of heparin. J. Control. Re-lease 45,163, 1997.16.Sano, S., Kato, K., and Ikada, Y. Introduction of functional groups onto the surface of polyethylene for protein immo-bilization. Biomaterials 14,817, 1993.17.Bubnis, W.A., and Ofner, C.M., III. The determination of ⑀-amino groups in soluble and poorly soluble proteinaceous materials by a spectrophotometric method using trini-trobenzenesulfonic acid. Anal. Biochem. 207,129, 1992.18.Zwadlo-Klarwasser, G., Görlitz, K., Hafemann, B., Klee,D., and Klosterhalfen, B. The chorioallantoic membrane of the chick embryo as a simple model for the study of the angiogenic and inflammatory response to biomaterials. J.Mater. Sci. Mater. Med. 12,195, 2001.19.van Wachem, P.B., Plantinga, J .A., Wissink, M.J .,Beernink, R., Poot, A.A., Engbers, G.H., Beugeling, T., van Aken, W.G., Feijen, J., and van Luyn, M.J. In vivo bio-compatibility of carbodiimide-crosslinked collagen matri-ces: Effects of crosslink density, heparin immobilization,and bFGF loading. J. Biomed. Mater. Res. 55,368, 2001.20.Soker, S., Machado, M., and Atala, A. Systems for thera-peutic angiogenesis in tissue engineering. World J. Urol.18,10, 2000.Address reprint requests to:G.C.M. Steffens, Ph.D.Department of Biochemistry and Molecular CellBiologyInstitute of Biochemistry RWTH Aachen UniversityPauwelsstrasse 3052074 Aachen, GermanyE-mail:gcm.steffens@post.rwth-aachen.de1509。
聚乙烯微塑料对玉米根际土壤微生物群落结构的影响
中国生态农业学报(中英文) 2021年6月 第29卷 第6期Chinese Journal of Eco-Agriculture, Jun. 2021, 29(6): 970-978* 国民核生化灾害防护国家重点实验室公开基金项目(SKLNBC2019-21)资助** 通信作者: 罗学刚, 主要研究方向为环境污染生物效应与生物修复研究。
E-mail: lxg@ 丁峰, 主要研究方向为环境污染生物效应与生物修复研究。
E-mail: 1946533708@ 收稿日期: 2020-08-17 接受日期: 2021-01-17* The study was supported by the Open Fund Project of the National Key Laboratory of National Nuclear and Biochemical Disaster Protection(SKLNBC2019-21).** Corresponding author, E-mail: lxg@DOI: 10.13930/ki.cjea.200677丁峰, 赖金龙, 季晓晖, 罗学刚. 聚乙烯微塑料对玉米根际土壤微生物群落结构的影响[J]. 中国生态农业学报(中英文), 2021, 29(6): 970-978DING F, LAI J L, JI X H, LUO X G. Effects of polyethylene microplastics on the microbial community structure of maize rhizosphere soil[J]. Chinese Journal of Eco-Agriculture, 2021, 29(6): 970-978聚乙烯微塑料对玉米根际土壤微生物群落结构的影响*丁 峰1, 赖金龙2, 季晓晖3, 罗学刚1,2**(1. 西南科技大学生命科学与工程学院 绵阳 621010; 2. 西南科技大学生物质材料教育部工程研究中心 绵阳 621000;3. 陕西理工大学化学与环境科学学院 汉中 723000)摘 要: 为了研究聚乙烯类微塑料对玉米根际土壤微生物群落结构的影响, 以玉米为试材, 以平均分子量为2000、5000、10万的聚乙烯粉末模拟土壤中的微塑料污染, 设置5个处理: 不添加聚乙烯(CK)、添加分子量为2000(T1)、5000(T2)、10万以上(T3)的聚乙烯且种植玉米、未添加聚乙烯未种植玉米(CK0), 分析玉米抽穗期各部位矿质元素代谢和根际土壤微生物群落结构差异。
Analysis of Genetic Diversity and Population Structure
Agricultural Sciences in China2010, 9(9): 1251-1262September 2010Received 30 October, 2009 Accepted 16 April, 2010Analysis of Genetic Diversity and Population Structure of Maize Landraces from the South Maize Region of ChinaLIU Zhi-zhai 1, 2, GUO Rong-hua 2, 3, ZHAO Jiu-ran 4, CAI Yi-lin 1, W ANG Feng-ge 4, CAO Mo-ju 3, W ANG Rong-huan 2, 4, SHI Yun-su 2, SONG Yan-chun 2, WANG Tian-yu 2 and LI Y u 21Maize Research Institute, Southwest University, Chongqing 400716, P.R.China2Institue of Crop Sciences/National Key Facility for Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences,Beijing 100081, P.R.China3Maize Research Institute, Sichuan Agricultural University, Ya’an 625014, P.R.China4Maize Research Center, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100089, P.R.ChinaAbstractUnderstanding genetic diversity and population structure of landraces is important in utilization of these germplasm in breeding programs. In the present study, a total of 143 core maize landraces from the South Maize Region (SR) of China,which can represent the general profile of the genetic diversity in the landraces germplasm of SR, were genotyped by 54DNA microsatellite markers. Totally, 517 alleles (ranging from 4 to 22) were detected among these landraces, with an average of 9.57 alleles per locus. The total gene diversity of these core landraces was 0.61, suggesting a rather higher level of genetic diversity. Analysis of population structure based on Bayesian method obtained the samilar result as the phylogeny neighbor-joining (NJ) method. The results indicated that the whole set of 143 core landraces could be clustered into two distinct groups. All landraces from Guangdong, Hainan, and 15 landraces from Jiangxi were clustered into group 1, while those from the other regions of SR formed the group 2. The results from the analysis of genetic diversity showed that both of groups possessed a similar gene diversity, but group 1 possessed relatively lower mean alleles per locus (6.63) and distinct alleles (91) than group 2 (7.94 and 110, respectively). The relatively high richness of total alleles and distinct alleles preserved in the core landraces from SR suggested that all these germplasm could be useful resources in germplasm enhancement and maize breeding in China.Key words :maize, core landraces, genetic diversity, population structureINTRODUCTIONMaize has been grown in China for nearly 500 years since its first introduction into this second biggest pro-duction country in the world. Currently, there are six different maize growing regions throughout the coun-try according to the ecological conditions and farming systems, including three major production regions,i.e., the North Spring Maize Region, the Huang-Huai-Hai Summer Maize Region, and the Southwest MaizeRegion, and three minor regions, i.e., the South Maize Region, the Northwest Maize Region, and the Qingzang Plateau Maize Region. The South Maize Region (SR)is specific because of its importance in origin of Chi-nese maize. It is hypothesized that Chinese maize is introduced mainly from two routes. One is called the land way in which maize was first brought to Tibet from India, then to Sichuan Province in southwestern China. The other way is that maize dispersed via the oceans, first shipped to the coastal areas of southeast China by boats, and then spread all round the country1252LIU Zhi-zhai et al.(Xu 2001; Zhou 2000). SR contains all of the coastal provinces and regions lie in southeastern China.In the long-term cultivation history of maize in south-ern China, numerous landraces have been formed, in which a great amount of genetic variation was observed (Li 1998). Similar to the hybrid swapping in Europe (Reif et al. 2005a), the maize landraces have been al-most replaced by hybrids since the 1950s in China (Li 1998). However, some landraces with good adapta-tions and yield performances are still grown in a few mountainous areas of this region (Liu et al.1999). Through a great effort of collection since the 1950s, 13521 accessions of maize landraces have been cur-rently preserved in China National Genebank (CNG), and a core collection of these landraces was established (Li et al. 2004). In this core collection, a total of 143 maize landrace accessions were collected from the South Maize Region (SR) (Table 1).Since simple sequence repeat ( SSR ) markers were firstly used in human genetics (Litt and Luty 1989), it now has become one of the most widely used markers in the related researches in crops (Melchinger et al. 1998; Enoki et al. 2005), especially in the molecular characterization of genetic resources, e.g., soybean [Glycine max (L.) Merr] (Xie et al. 2005), rice (Orya sativa L.) (Garris et al. 2005), and wheat (Triticum aestivum) (Chao et al. 2007). In maize (Zea mays L.), numerous studies focusing on the genetic diversity and population structure of landraces and inbred lines in many countries and regions worldwide have been pub-lished (Liu et al. 2003; Vegouroux et al. 2005; Reif et al. 2006; Wang et al. 2008). These activities of documenting genetic diversity and population structure of maize genetic resources have facilitated the under-standing of genetic bases of maize landraces, the utili-zation of these resources, and the mining of favorable alleles from landraces. Although some studies on ge-netic diversity of Chinese maize inbred lines were con-ducted (Yu et al. 2007; Wang et al. 2008), the general profile of genetic diversity in Chinese maize landraces is scarce. Especially, there are not any reports on ge-netic diversity of the maize landraces collected from SR, a possibly earliest maize growing area in China. In this paper, a total of 143 landraces from SR listed in the core collection of CNG were genotyped by using SSR markers, with the aim of revealing genetic diver-sity of the landraces from SR (Table 2) of China and examining genetic relationships and population struc-ture of these landraces.MATERIALS AND METHODSPlant materials and DNA extractionTotally, 143 landraces from SR which are listed in the core collection of CNG established by sequential strati-fication method (Liu et al. 2004) were used in the present study. Detailed information of all these landrace accessions is listed in Table 1. For each landrace, DNA sample was extracted by a CTAB method (Saghi-Maroof et al. 1984) from a bulk pool constructed by an equal-amount of leaves materials sampled from 15 random-chosen plants of each landrace according to the proce-dure of Reif et al. (2005b).SSR genotypingA total of 54 simple sequence repeat (SSR) markers covering the entire maize genome were screened to fin-gerprint all of the 143 core landrace accessions (Table 3). 5´ end of the left primer of each locus was tailed by an M13 sequence of 5´-CACGACGTTGTAAAACGAC-3´. PCR amplification was performed in a 15 L reac-tion containing 80 ng of template DNA, 7.5 mmol L-1 of each of the four dNTPs, 1×Taq polymerase buffer, 1.5 mmol L-1 MgCl2, 1 U Taq polymerase (Tiangen Biotech Co. Ltd., Beijing, China), 1.2 mol L-1 of forward primer and universal fluorescent labeled M13 primer, and 0.3 mol L-1 of M13 sequence tailed reverse primer (Schuelke 2000). The amplification was carried out in a 96-well DNA thermal cycler (GeneAmp PCR System 9700, Applied Biosystem, USA). PCR products were size-separated on an ABI Prism 3730XL DNA sequencer (HitachiHigh-Technologies Corporation, Tokyo, Japan) via the software packages of GENEMAPPER and GeneMarker ver. 6 (SoftGenetics, USA).Data analysesAverage number of alleles per locus and average num-ber of group-specific alleles per locus were identifiedAnalysis of Genetic Diversity and Population Structure of Maize Landraces from the South Maize Region of China 1253Table 1 The detailed information about the landraces used in the present studyPGS revealed by Structure1) NJ dendragram revealed Group 1 Group 2 by phylogenetic analysis140-150tian 00120005AnH-06Jingde Anhui 0.0060.994Group 2170tian00120006AnH-07Jingde Anhui 0.0050.995Group 2Zixihuangyumi00120007AnH-08Zixi Anhui 0.0020.998Group 2Zixibaihuangzayumi 00120008AnH-09Zixi Anhui 0.0030.997Group 2Baiyulu 00120020AnH-10Yuexi Anhui 0.0060.994Group 2Wuhuazi 00120021AnH-11Yuexi Anhui 0.0030.997Group 2Tongbai 00120035AnH-12Tongling Anhui 0.0060.994Group 2Yangyulu 00120036AnH-13Yuexi Anhui 0.0040.996Group 2Huangli 00120037AnH-14Tunxi Anhui 0.0410.959Group 2Baiyumi 00120038AnH-15Tunxi Anhui 0.0030.997Group 2Dapigu00120039AnH-16Tunxi Anhui 0.0350.965Group 2150tianbaiyumi 00120040AnH-17Xiuning Anhui 0.0020.998Group 2Xiuning60tian 00120042AnH-18Xiuning Anhui 0.0040.996Group 2Wubaogu 00120044AnH-19ShitaiAnhui 0.0020.998Group 2Kuyumi00130001FuJ-01Shanghang Fujian 0.0050.995Group 2Zhongdouyumi 00130003FuJ-02Shanghang Fujian 0.0380.962Group 2Baixinyumi 00130004FuJ-03Liancheng Fujian 0.0040.996Group 2Hongxinyumi 00130005FuJ-04Liancheng Fujian 0.0340.966Group 2Baibaogu 00130008FuJ-05Changding Fujian 0.0030.997Group 2Huangyumi 00130011FuJ-06Jiangyang Fujian 0.0020.998Group 2Huabaomi 00130013FuJ-07Shaowu Fujian 0.0020.998Group 2Huangbaomi 00130014FuJ-08Songxi Fujian 0.0020.998Group 2Huangyumi 00130016FuJ-09Wuyishan Fujian 0.0460.954Group 2Huabaogu 00130019FuJ-10Jian’ou Fujian 0.0060.994Group 2Huangyumi 00130024FuJ-11Guangze Fujian 0.0010.999Group 2Huayumi 00130025FuJ-12Nanping Fujian 0.0040.996Group 2Huangyumi 00130026FuJ-13Nanping Fujian 0.0110.989Group 2Hongbaosu 00130027FuJ-14Longyan Fujian 0.0160.984Group 2Huangfansu 00130029FuJ-15Loangyan Fujian 0.0020.998Group 2Huangbaosu 00130031FuJ-16Zhangping Fujian 0.0060.994Group 2Huangfansu 00130033FuJ-17Zhangping Fujian0.0040.996Group 2Baolieyumi 00190001GuangD-01Guangzhou Guangdong 0.9890.011Group 1Nuomibao (I)00190005GuangD-02Shixing Guangdong 0.9740.026Group 1Nuomibao (II)00190006GuangD-03Shixing Guangdong 0.9790.021Group 1Zasehuabao 00190010GuangD-04Lechang Guangdong 0.9970.003Group 1Zihongmi 00190013GuangD-05Lechang Guangdong 0.9880.012Group 1Jiufengyumi 00190015GuangD-06Lechang Guangdong 0.9950.005Group 1Huangbaosu 00190029GuangD-07MeiGuangdong 0.9970.003Group 1Bailibao 00190032GuangD-08Xingning Guangdong 0.9980.002Group 1Nuobao00190038GuangD-09Xingning Guangdong 0.9980.002Group 1Jinlanghuang 00190048GuangD-10Jiangcheng Guangdong 0.9960.004Group 1Baimizhenzhusu 00190050GuangD-11Yangdong Guangdong 0.9940.006Group 1Huangmizhenzhusu 00190052GuangD-12Yangdong Guangdong 0.9930.007Group 1Baizhenzhu 00190061GuangD-13Yangdong Guangdong 0.9970.003Group 1Baiyumi 00190066GuangD-14Wuchuan Guangdong 0.9880.012Group 1Bendibai 00190067GuangD-15Suixi Guangdong 0.9980.002Group 1Shigubaisu 00190068GuangD-16Gaozhou Guangdong 0.9960.004Group 1Zhenzhusu 00190069GuangD-17Xinyi Guangdong 0.9960.004Group 1Nianyaxixinbai 00190070GuangD-18Huazhou Guangdong 0.9960.004Group 1Huangbaosu 00190074GuangD-19Xinxing Guangdong 0.9950.005Group 1Huangmisu 00190076GuangD-20Luoding Guangdong 0.940.060Group 1Huangmi’ai 00190078GuangD-21Luoding Guangdong 0.9980.002Group 1Bayuemai 00190084GuangD-22Liannan Guangdong 0.9910.009Group 1Baiyumi 00300001HaiN-01Haikou Hainan 0.9960.004Group 1Baiyumi 00300003HaiN-02Sanya Hainan 0.9970.003Group 1Hongyumi 00300004HaiN-03Sanya Hainan 0.9980.002Group 1Baiyumi00300011HaiN-04Tongshi Hainan 0.9990.001Group 1Zhenzhuyumi 00300013HaiN-05Tongshi Hainan 0.9980.002Group 1Zhenzhuyumi 00300015HaiN-06Qiongshan Hainan 0.9960.004Group 1Aiyumi 00300016HaiN-07Qiongshan Hainan 0.9960.004Group 1Huangyumi 00300021HaiN-08Qionghai Hainan 0.9970.003Group 1Y umi 00300025HaiN-09Qionghai Hainan 0.9870.013Group 1Accession name Entry code Analyzing code Origin (county/city)Province/Region1254LIU Zhi-zhai et al .Baiyumi00300032HaiN-10Tunchang Hainan 0.9960.004Group 1Huangyumi 00300051HaiN-11Baisha Hainan 0.9980.002Group 1Baihuangyumi 00300055HaiN-12BaishaHainan 0.9970.003Group 1Machihuangyumi 00300069HaiN-13Changjiang Hainan 0.9900.010Group 1Hongyumi00300073HaiN-14Dongfang Hainan 0.9980.002Group 1Xiaohonghuayumi 00300087HaiN-15Lingshui Hainan 0.9980.002Group 1Baiyumi00300095HaiN-16Qiongzhong Hainan 0.9950.005Group 1Y umi (Baimai)00300101HaiN-17Qiongzhong Hainan 0.9980.002Group 1Y umi (Xuemai)00300103HaiN-18Qiongzhong Hainan 0.9990.001Group 1Huangmaya 00100008JiangS-10Rugao Jiangsu 0.0040.996Group 2Bainian00100012JiangS-11Rugao Jiangsu 0.0080.992Group 2Bayebaiyumi 00100016JiangS-12Rudong Jiangsu 0.0040.996Group 2Chengtuohuang 00100021JiangS-13Qidong Jiangsu 0.0050.995Group 2Xuehuanuo 00100024JiangS-14Qidong Jiangsu 0.0020.998Group 2Laobaiyumi 00100032JiangS-15Qidong Jiangsu 0.0050.995Group 2Laobaiyumi 00100033JiangS-16Qidong Jiangsu 0.0010.999Group 2Huangwuye’er 00100035JiangS-17Hai’an Jiangsu 0.0030.997Group 2Xiangchuanhuang 00100047JiangS-18Nantong Jiangsu 0.0060.994Group 2Huangyingzi 00100094JiangS-19Xinghua Jiangsu 0.0040.996Group 2Xiaojinhuang 00100096JiangS-20Yangzhou Jiangsu 0.0010.999Group 2Liushizi00100106JiangS-21Dongtai Jiangsu 0.0030.997Group 2Kangnandabaizi 00100108JiangS-22Dongtai Jiangsu 0.0020.998Group 2Shanyumi 00140020JiangX-01Dexing Jiangxi 0.9970.003Group 1Y umi00140024JiangX-02Dexing Jiangxi 0.9970.003Group 1Tianhongyumi 00140027JiangX-03Yushan Jiangxi 0.9910.009Group 1Hongganshanyumi 00140028JiangX-04Yushan Jiangxi 0.9980.002Group 1Zaoshuyumi 00140032JiangX-05Qianshan Jiangxi 0.9970.003Group 1Y umi 00140034JiangX-06Wannian Jiangxi 0.9970.003Group 1Y umi 00140038JiangX-07De’an Jiangxi 0.9940.006Group 1Y umi00140045JiangX-08Wuning Jiangxi 0.9740.026Group 1Chihongyumi 00140049JiangX-09Wanzai Jiangxi 0.9920.008Group 1Y umi 00140052JiangX-10Wanzai Jiangxi 0.9930.007Group 1Huayumi 00140060JiangX-11Jing’an Jiangxi 0.9970.003Group 1Baiyumi 00140065JiangX-12Pingxiang Jiangxi 0.9940.006Group 1Huangyumi00140066JiangX-13Pingxiang Jiangxi 0.9680.032Group 1Nuobaosuhuang 00140068JiangX-14Ruijin Jiangxi 0.9950.005Group 1Huangyumi 00140072JiangX-15Xinfeng Jiangxi 0.9960.004Group 1Wuningyumi 00140002JiangX-16Jiujiang Jiangxi 0.0590.941Group 2Tianyumi 00140005JiangX-17Shangrao Jiangxi 0.0020.998Group 2Y umi 00140006JiangX-18Shangrao Jiangxi 0.0310.969Group 2Baiyiumi 00140012JiangX-19Maoyuan Jiangxi 0.0060.994Group 260riyumi 00140016JiangX-20Maoyuan Jiangxi 0.0020.998Group 2Shanyumi 00140019JiangX-21Dexing Jiangxi 0.0050.995Group 2Laorenya 00090002ShangH-01Chongming Shanghai 0.0050.995Group 2Jinmeihuang 00090004ShangH-02Chongming Shanghai 0.0020.998Group 2Zaobaiyumi 00090006ShangH-03Chongming Shanghai 0.0020.998Group 2Chengtuohuang 00090007ShangH-04Chongming Shanghai 0.0780.922Group 2Benyumi (Huang)00090008ShangH-05Shangshi Shanghai 0.0020.998Group 2Bendiyumi 00090010ShangH-06Shangshi Shanghai 0.0040.996Group 2Baigengyumi 00090011ShangH-07Jiading Shanghai 0.0020.998Group 2Huangnuoyumi 00090012ShangH-08Jiading Shanghai 0.0040.996Group 2Huangdubaiyumi 00090013ShangH-09Jiading Shanghai 0.0440.956Group 2Bainuoyumi 00090014ShangH-10Chuansha Shanghai 0.0010.999Group 2Laorenya 00090015ShangH-11Shangshi Shanghai 0.0100.990Group 2Xiaojinhuang 00090016ShangH-12Shangshi Shanghai 0.0050.995Group 2Gengbaidayumi 00090017ShangH-13Shangshi Shanghai 0.0020.998Group 2Nongmeiyihao 00090018ShangH-14Shangshi Shanghai 0.0540.946Group 2Chuanshazinuo 00090020ShangH-15Chuansha Shanghai 0.0550.945Group 2Baoanshanyumi 00110004ZheJ-01Jiangshan Zhejiang 0.0130.987Group 2Changtaixizi 00110005ZheJ-02Jiangshan Zhejiang 0.0020.998Group 2Shanyumibaizi 00110007ZheJ-03Jiangshan Zhejiang 0.0020.998Group 2Kaihuajinyinbao 00110017ZheJ-04Kaihua Zhejiang 0.0100.990Group 2Table 1 (Continued from the preceding page)PGS revealed by Structure 1) NJ dendragram revealed Group1 Group2 by phylogenetic analysisAccession name Entry code Analyzing code Origin (county/city)Province/RegoinAnalysis of Genetic Diversity and Population Structure of Maize Landraces from the South Maize Region of China 1255Liputianzi00110038ZheJ-05Jinhua Zhejiang 0.0020.998Group 2Jinhuaqiuyumi 00110040ZheJ-06Jinhua Zhejiang 0.0050.995Group 2Pujiang80ri 00110069ZheJ-07Pujiang Zhejiang 0.0210.979Group 2Dalihuang 00110076ZheJ-08Yongkang Zhejiang 0.0140.986Group 2Ziyumi00110077ZheJ-09Yongkang Zhejiang 0.0020.998Group 2Baiyanhandipinzhong 00110078ZheJ-10Yongkang Zhejiang 0.0030.997Group 2Duosuiyumi00110081ZheJ-11Wuyi Zhejiang 0.0020.998Group 2Chun’an80huang 00110084ZheJ-12Chun’an Zhejiang 0.0020.998Group 2120ribaiyumi 00110090ZheJ-13Chun’an Zhejiang 0.0020.998Group 2Lin’anliugu 00110111ZheJ-14Lin’an Zhejiang 0.0030.997Group 2Qianhuangyumi00110114ZheJ-15Lin’an Zhejiang 0.0030.997Group 2Fenshuishuitianyumi 00110118ZheJ-16Tonglu Zhejiang 0.0410.959Group 2Kuihualiugu 00110119ZheJ-17Tonglu Zhejiang 0.0030.997Group 2Danbaihuang 00110122ZheJ-18Tonglu Zhejiang 0.0020.998Group 2Hongxinma 00110124ZheJ-19Jiande Zhejiang 0.0030.997Group 2Shanyumi 00110136ZheJ-20Suichang Zhejiang 0.0030.997Group 2Bai60ri 00110143ZheJ-21Lishui Zhejiang 0.0050.995Group 2Zeibutou 00110195ZheJ-22Xianju Zhejiang 0.0020.998Group 2Kelilao00110197ZheJ-23Pan’an Zhejiang 0.0600.940Group 21)The figures refered to the proportion of membership that each landrace possessed.Table 1 (Continued from the preceding page)PGS revealed by Structure 1) NJ dendragram revealed Group 1 Group 2 by phylogenetic analysisAccession name Entry code Analyzing code Origin (county/city)Province/Regoin Table 2 Construction of two phylogenetic groups (SSR-clustered groups) and their correlation with geographical locationsGeographical location SSR-clustered groupChi-square testGroup 1Group 2Total Guangdong 2222 χ2 = 124.89Hainan 1818P < 0.0001Jiangxi 15621Anhui 1414Fujian 1717Jiangsu 1313Shanghai 1515Zhejiang 2323Total5588143by the software of Excel MicroSatellite toolkit (Park 2001). Average number of alleles per locus was calcu-lated by the formula rAA rj j¦1, with the standarddeviation of1)()(12¦ r A AA rj jV , where A j was thenumber of distinct alleles at locus j , and r was the num-ber of loci (Park 2001).Unbiased gene diversity also known as expected heterozygosity, observed heterozygosity for each lo-cus and average gene diversity across the 54 SSR loci,as well as model-based groupings inferred by Struc-ture ver. 2.2, were calculated by the softwarePowerMarker ver.3.25 (Liu et al . 2005). Unbiased gene diversity for each locus was calculated by˅˄¦ 2ˆ1122ˆi x n n h , where 2ˆˆ2ˆ2¦¦z ji ijij i X X x ,and ij X ˆwas the frequency of genotype A i A jin the sample, and n was the number of individuals sampled.The average gene diversity across 54 loci was cal-culated as described by Nei (1987) as follows:rh H rj j ¦1ˆ, with the variance ,whereThe average observed heterozygosity across the en-tire loci was calculated as described by (Hedrick 1983)as follows: r jrj obsobs n h h ¦1, with the standard deviationrn h obs obsobs 1V1256LIU Zhi-zhai et al.Phylogenetic analysis and population genetic structureRelationships among all of the 143 accessions collected from SR were evaluated by using the unweighted pair group method with neighbor-joining (NJ) based on the log transformation of the proportion of shared alleles distance (InSPAD) via PowerMarker ver. 3.25 (FukunagaTable 3 The PIC of each locus and the number of alleles detected by 54 SSRsLocus Bin Repeat motif PIC No. of alleles Description 2)bnlg1007y51) 1.02AG0.7815Probe siteumc1122 1.06GGT0.639Probe siteumc1147y41) 1.07CA0.2615Probe sitephi961001) 2.00ACCT0.298Probe siteumc1185 2.03GC0.7215ole1 (oleosin 1)phi127 2.08AGAC0.577Probe siteumc1736y21) 2.09GCA T0.677Probe sitephi453121 3.01ACC0.7111Probe sitephi374118 3.03ACC0.477Probe sitephi053k21) 3.05A TAC0.7910Probe sitenc004 4.03AG0.4812adh2 (alcohol dehydrogenase 2)bnlg490y41) 4.04T A0.5217Probe sitephi079 4.05AGATG0.495gpc1(glyceraldehyde-3-phosphate dehydrogenase 1) bnlg1784 4.07AG0.6210Probe siteumc1574 4.09GCC0.719sbp2 (SBP-domain protein 2)umc1940y51) 4.09GCA0.4713Probe siteumc1050 4.11AA T0.7810cat3 (catalase 3)nc130 5.00AGC0.5610Probe siteumc2112y31) 5.02GA0.7014Probe sitephi109188 5.03AAAG0.719Probe siteumc1860 5.04A T0.325Probe sitephi085 5.07AACGC0.537gln4 (glutamine synthetase 4)phi331888 5.07AAG0.5811Probe siteumc1153 5.09TCA0.7310Probe sitephi075 6.00CT0.758fdx1 (ferredoxin 1)bnlg249k21) 6.01AG0.7314Probe sitephi389203 6.03AGC0.416Probe sitephi299852y21) 6.07AGC0.7112Probe siteumc1545y21)7.00AAGA0.7610hsp3(heat shock protein 3)phi1127.01AG0.5310o2 (opaque endosperm 2)phi4207018.00CCG0.469Probe siteumc13598.00TC0.7814Probe siteumc11398.01GAC0.479Probe siteumc13048.02TCGA0.335Probe sitephi1158.03A TAC0.465act1(actin1)umc22128.05ACG0.455Probe siteumc11218.05AGAT0.484Probe sitephi0808.08AGGAG0.646gst1 (glutathione-S-transferase 1)phi233376y11)8.09CCG0.598Probe sitebnlg12729.00AG0.8922Probe siteumc20849.01CTAG0.498Probe sitebnlg1520k11)9.01AG0.5913Probe sitephi0659.03CACCT0.519pep1(phosphoenolpyruvate carboxylase 1)umc1492y131)9.04GCT0.2514Probe siteumc1231k41)9.05GA0.2210Probe sitephi1084119.06AGCT0.495Probe sitephi4488809.06AAG0.7610Probe siteumc16759.07CGCC0.677Probe sitephi041y61)10.00AGCC0.417Probe siteumc1432y61)10.02AG0.7512Probe siteumc136710.03CGA0.6410Probe siteumc201610.03ACAT0.517pao1 (polyamine oxidase 1)phi06210.04ACG0.337mgs1 (male-gametophyte specific 1)phi07110.04GGA0.515hsp90 (heat shock protein, 90 kDa)1) These primers were provided by Beijing Academy of Agricultural and Forestry Sciences (Beijing, China).2) Searched from Analysis of Genetic Diversity and Population Structure of Maize Landraces from the South Maize Region of China1257et al. 2005). The unrooted phylogenetic tree was finally schematized with the software MEGA (molecular evolu-tionary genetics analysis) ver. 3.1 (Kumar et al. 2004). Additionally, a chi-square test was used to reveal the correlation between the geographical origins and SSR-clustered groups through FREQ procedure implemented in SAS ver. 9.0 (2002, SAS Institute, Inc.).In order to reveal the population genetic structure (PGS) of 143 landrace accessions, a Bayesian approach was firstly applied to determine the number of groups (K) that these materials should be assigned by the soft-ware BAPS (Bayesian Analysis of Population Structure) ver.5.1. By using BAPS, a fixed-K clustering proce-dure was applied, and with each separate K, the num-ber of runs was set to 100, and the value of log (mL) was averaged to determine the appropriate K value (Corander et al. 2003; Corander and Tang 2007). Since the number of groups were determined, a model-based clustering analysis was used to assign all of the acces-sions into the corresponding groups by an admixture model and a correlated allele frequency via software Structure ver.2.2 (Pritchard et al. 2000; Falush et al. 2007), and for the given K value determined by BAPS, three independent runs were carried out by setting both the burn-in period and replication number 100000. The threshold probability assigned individuals into groupswas set by 0.8 (Liu et al. 2003). The PGS result carried out by Structure was visualized via Distruct program ver. 1.1 (Rosenberg 2004).RESULTSGenetic diversityA total of 517 alleles were detected by the whole set of54 SSRs covering the entire maize genome through all of the 143 maize landraces, with an average of 9.57 alleles per locus and ranged from 4 (umc1121) to 22 (bnlg1272) (Table 3). Among all the alleles detected, the number of distinct alleles accounted for 132 (25.53%), with an av-erage of 2.44 alleles per locus. The distinct alleles dif-fered significantly among the landraces from different provinces/regions, and the landraces from Guangdong, Fujian, Zhejiang, and Shanghai possessed more distinct alleles than those from the other provinces/regions, while those from southern Anhui possessed the lowest distinct alleles, only counting for 3.28% of the total (Table 4).Table 4 The genetic diversity within eight provinces/regions and groups revealed by 54 SSRsProvince/Region Sample size Allele no.1)Distinct allele no.Gene diversity (expected heterozygosity)Observed heterozygosity Anhui14 4.28 (4.19) 69 (72.4)0.51 (0.54)0.58 (0.58)Fujian17 4.93 (4.58 80 (79.3)0.56 (0.60)0.63 (0.62)Guangdong22 5.48 (4.67) 88 (80.4)0.57 (0.59)0.59 (0.58)Hainan18 4.65 (4.26) 79 (75.9)0.53 (0.57)0.55 (0.59)Jiangsu13 4.24 700.500.55Jiangxi21 4.96 (4.35) 72 (68.7)0.56 (0.60)0.68 (0.68)Shanghai15 5.07 (4.89) 90 (91.4)0.55 (0.60)0.55 (0.55)Zhejiang23 5.04 (4.24) 85 (74)0.53 (0.550.60 (0.61)Total/average1439.571320.610.60GroupGroup 155 6.63 (6.40) 91 (89.5)0.57 (0.58)0.62 (0.62)Group 2887.94 (6.72)110 (104.3)0.57 (0.57)0.59 (0.58)Total/Average1439.571320.610.60Provinces/Regions within a groupGroup 1Total55 6.69 (6.40) 910.57 (0.58)0.62 (0.62)Guangdong22 5.48 (4.99) 86 (90.1)0.57 (0.60)0.59 (0.58)Hainan18 4.65 (4.38) 79 (73.9)0.53 (0.56)0.55 (0.59)Jiangxi15 4.30 680.540.69Group 2Total887.97 (6.72)110 (104.3)0.57 (0.57)0.59 (0.58)Anhui14 4.28 (3.22) 69 (63.2)0.51 (0.54)0.58 (0.57)Fujian17 4.93 (3.58) 78 (76.6)0.56 (0.60)0.63 (0.61)Jiangsu13 4.24 (3.22) 71 (64.3)0.50 (0.54)0.55 (0.54)Jiangxi6 3.07 520.460.65Shanghai15 5.07 (3.20) 91 (84.1)0.55 (0.60)0.55 (0.54)Zhejiang23 5.04 (3.20) 83 (61.7)0.53 (0.54)0.60 (0.58)1258LIU Zhi-zhai et al.Among the 54 loci used in the study, 16 (or 29.63%) were dinucleotide repeat SSRs, which were defined as type class I-I, the other 38 loci were SSRs with a longer repeat motifs, and two with unknown repeat motifs, all these 38 loci were defined as the class of I-II. In addition, 15 were located within certain functional genes (defined as class II-I) and the rest were defined as class II-II. The results of comparison indicated that the av-erage number of alleles per locus captured by class I-I and II-II were 12.88 and 10.05, respectively, which were significantly higher than that by type I-II and II-I (8.18 and 8.38, respectively). The gene diversity re-vealed by class I-I (0.63) and II-I (0.63) were some-what higher than by class I-II (0.60) and II-II (0.60) (Table 5).Genetic relationships of the core landraces Overall, 143 landraces were clustered into two groups by using neighbor-joining (NJ) method based on InSPAD. All the landraces from provinces of Guangdong and Hainan and 15 of 21 from Jiangxi were clustered together to form group 1, and the other 88 landraces from the other provinces/regions formed group 2 (Fig.-B). The geographical origins of all these 143 landraces with the clustering results were schematized in Fig.-D. Revealed by the chi-square test, the phylogenetic results (SSR-clustered groups) of all the 143 landraces from provinces/regions showed a significant correlation with their geographical origin (χ2=124.89, P<0.0001, Table 2).Revealed by the phylogenetic analysis based on the InSPAD, the minimum distance was observed as 0.1671 between two landraces, i.e., Tianhongyumi (JiangX-03) and Hongganshanyumi (JiangX-04) collected from Jiangxi Province, and the maximum was between two landraces of Huangbaosu (FuJ-16) and Hongyumi (HaiN-14) collected from provinces of Fujian and Hainan, respectively, with the distance of 1.3863 (data not shown). Two landraces (JiangX-01 and JiangX-21) collected from the same location of Dexing County (Table 1) possessing the same names as Shanyumi were separated to different groups, i.e., JiangX-01 to group1, while JiangX-21 to group 2 (Table 1). Besides, JiangX-01 and JiangX-21 showed a rather distant distance of 0.9808 (data not shown). These results indicated that JiangX-01 and JiangX-21 possibly had different ances-tral origins.Population structureA Bayesian method was used to detect the number of groups (K value) of the whole set of landraces from SR with a fixed-K clustering procedure implemented in BAPS software ver. 5.1. The result showed that all of the 143 landraces could also be assigned into two groups (Fig.-A). Then, a model-based clustering method was applied to carry out the PGS of all the landraces via Structure ver. 2.2 by setting K=2. This method as-signed individuals to groups based on the membership probability, thus the threshold probability 0.80 was set for the individuals’ assignment (Liu et al. 2003). Accordingly, all of the 143 landraces were divided into two distinct model-based groups (Fig.-C). The landraces from Guangdong, Hainan, and 15 landraces from Jiangxi formed one group, while the rest 6 landraces from the marginal countries of northern Jiangxi and those from the other provinces formed an-other group (Table 1, Fig.-D). The PGS revealed by the model-based approach via Structure was perfectly consistent with the relationships resulted from the phy-logenetic analysis via PowerMarker (Table 1).DISCUSSIONThe SR includes eight provinces, i.e., southern Jiangsu and Anhui, Shanghai, Zhejiang, Fujian, Jiangxi, Guangdong, and Hainan (Fig.-C), with the annual maize growing area of about 1 million ha (less than 5% of theTable 5 The genetic diversity detected with different types of SSR markersType of locus No. of alleles Gene diversity Expected heterozygosity PIC Class I-I12.880.630.650.60 Class I-II8.180.600.580.55 Class II-I8.330.630.630.58。
拟黑多刺蚁肌细胞增强因子2_MEF2_生物信息学分析解读
拟黑多刺蚁肌细胞增强因子2 WORD文档使用说明：拟黑多刺蚁肌细胞增强因子2 来源于本WOED文件是采用在线转换功能下载而来，因此在排版和显示效果方面可能不能满足您的应用需求。
如果需要查看原版WOED文件，请访问这里拟黑多刺蚁肌细胞增强因子2 文件原版地址:/d1dd5df7170b1a40fffdaf26.pdf拟黑多刺蚁肌细胞增强因子2|PDF转换成WROD_PDF阅读器下载昆虫知识 Chinese Bulletin of Entomology2010， 47（5）：881 ～ 885拟黑多刺蚁肌细胞增强因子 2 （ MEF2）生物信息学分析 * 郭新军（1. 陕西师范大学生命科学学院西安 1， 2奚耕思1? ? 西安 710065 ）710062 ； 2. 西安文理学院生命科学系2 ? Bioinformatics analysis of MEF2 gene of Polyrhachis vicina. GUO Xin-Jun 1 ，， Geng-Si1 ?（ 1. College of XILife Science， Shaanxi Nomal University，Xi ’an an University of Arts and Science，Xi’ Abstract710062， China； 2. Department of Life Science，Xi ’an710065，China）The analytical tools NCBI，ExPASy and CBS wereadopted to analyze the bioinformatic properties ofthe PvMEF2 protein，such as sequence characteristics，physicochemical properties，structure and functional domains. The results show that PvMEF2 has conserved MADS and MEF2 domains and that its physicochemical properties， secondary and tertiary structures are similar to those of the MEF2 protein of Drosophila melanogaster. PvMEF2 protein may play an importantrole in myogenesis in Polyrhachis vicina Roger. Key words Polyrhachis vicina， myocyte enhancer factor 2 （ MEF2）， bioinformatics analysis摘要ExPASy 在线核苷酸序列分析工具、 CBS 生物学序列分析工具及应用 NCBI 上的常用程序、SABLE 在线分析软件等对拟黑多刺蚁 Polyrhachis vicina Roger 肌细胞增强因子 2 （ PvMEF2 ）进行了生物信息学分析，获得了 PvMEF2 因子的序列特征及理化性质，并对其结构和功能结构域进行了预测。
修正摩尔库伦模型下的深基坑变形数值分析
第40卷第2期辽宁工程技术大学学报（自然科学版）2021年4月Vol.40 No.2 Journal of Liaoning Technical University（Natural Science）Apr. 2021 胡建林,孙利成,崔宏环,邵博源,王晟华.修正摩尔库伦模型下的深基坑变形数值分析[J].辽宁工程技术大学学报(自然科学版),2021,40(2):134-140.doi:10.11956/j.issn.1008-0562.2021.02.006HU Jianlin,SUN Licheng,CUI Honghuan,SHAO Boyuan,WANG Chenghua.Numerical analysis of deep foundation pit deformation based on modified Mohr Coulomb model[J].Journal of Liaoning Technical University(Natural Science), 2021,40(2):134-140. doi:10.11956/j.issn.1008-0562.2021.02.006修正摩尔库伦模型下的深基坑变形数值分析胡建林1，孙利成1，崔宏环1，邵博源1，王晟华2（1.河北建筑工程学院土木工程学院，河北张家口 075000；2.北旺建设集团有限公司勘察设计室，河北承德 067000）摘要：为研究修正摩尔库伦模型及其参数对于模拟深基坑变形的影响，运用实验和有限元分析的方法，分析摩尔库伦和修正摩尔库伦模型在模拟深基坑排桩支护变形和地表沉降中的不同特点，通过与实际监测结果进行对比分析，得到了修正摩尔库伦模型对于模拟深基坑变形的适用性.研究结果表明：在地表沉降和排桩水平位移预测上，摩尔库伦模型预测沉降值与实测值相差较大；不同参考应力下的修正摩尔库伦模型预测值与实测值的位移规律曲线较为吻合.研究结论揭示了使用不同参考应力下的修正摩尔库伦本构模型进行基坑开挖变形预测更具参考价值.关键词：基坑变形；修正摩尔库伦模型；模量参数；参考应力；实况监测中图分类号：TU 9 文献标志码：A 文章编号：1008-0562(2021)02-0134-07Numerical analysis of deep foundation pit deformation based onmodified Mohr Coulomb modelHU Jianlin1, SUN Licheng1, CUI Honghuan1, SHAO Boyuan1, WANG Chenghua2(1. College of Civil Engineering, Hebei University of Architectural Engineering, Zhangjiakou 075000, China; 2. Survey and Design Office, Beiwang Construction Group Company with Limited Liability,Chengde 067000, China)Abstract: In order to study the modified Mohr Coulomb model and its parameters for simulating the effect of deformation of deep foundation pit, experimental and finite element analysis method are used to analyze the Mohr Coulomb and modified Mohr Coulomb model pile in the simulation of deep foundation pit support different features of deformation and surface subsidence. Through comparative analysis with the actual monitoring results, the applicability of the modified Mohr Coulomb model for simulating the deep foundation pit deformation is obtained. The results show that in the prediction of surface settlement and horizontal displacement of pile row, the settlement value predicted by using Mohr Coulomb model differs greatly from the measured value; the predicted values of modified Mohr Coulomb model under different reference stresses are more consistent with the measured displacement curves. The research results show that the modified Moor Coulomb constitutive model under different reference stresses is more valuable for the excavation deformation prediction.Key words: foundation pit deformation; modified Moore Coulomb model; modulus parameters; reference stress; monitoring of live收稿日期：2020-05-06基金项目：国家自然科学基金（51878242）；张家口市科技局科技计划项目（1911035A）；河北建筑工程学院创新基金（XB201918）作者简介：胡建林（1986-），男，河北张家口人，硕士，讲师，主要从事岩土工程方面的研究.第2期胡建林，等：修正摩尔库伦模型下的深基坑变形数值分析1350 引言随着中国城镇化的快速发展，土地资源的紧缺，深基坑工程越来越多，而且基坑周边环境也越来越复杂，在基坑的设计和使用过程中变形控制往往成为主要因素，所以对深基坑支护的变形特性进行研究就显得尤为重要.数值分析被认为是一种有效的研究手段.国内外学者[1-4]基于数值分析对深基坑的变形特性展开了大量研究，也取得了一系列的成果.曾超峰[5]、赵秀绍[6]等运用不同数值分析软件进行基坑开挖数值模拟研究，通过分析计算结果与实测数值的关系，得到适用于不同土层的本构模型.研究表明，在数值分析中本构模型的选择对于计算结果影响很大，所以选择可以正确反映土体变形特征的本构模型对数值分析来说至关重要.由于参数少，而且容易获取，在数值分析中本构模型的选择目前还是以采用以莫尔-库伦破坏准则为基础的理想弹塑性模型为主.但是对于岩土材料来说，Mohr-Coulomb破坏准则存在缺陷，开挖卸载过程中土体的回弹模量和压缩模量均采用弹性模量的假设，会致使采用MC模型的计算结果与实测数据相比相差较大，甚至在变形规律上也往往存在较大差异.王卫东[7]等利用PLAXIS软件中的硬化土模型进行深基坑工程的有限元分析，通过试验获得相关参数，模拟得到较好的预测效果，证明该模型在基坑开挖中的适用性，该模型参数的取值与参考围压应力有关，对于数十米深的基坑，不同深度处围压差距较大，模量参数会随着侧限应力的不同而改变，所以参考应力的选择也至关重要.本文依托于实际工程案例，采用可以考虑加载和卸载时弹性模量不同的修正摩尔库伦模型进行有限元分析，模型参数根据室内试验获取，并且分析模型参数采用不同参考围压对计算结果的影响，获得较好模拟结果，为类似工程提供参考.1 深基坑工程概况深基坑工程场地位于河北省张家口市，地处清水河冲洪积扇中下部地貌单元.基坑呈多边形，南北向长约48 m，东西向宽约37 m，开挖深度约为14 m，边壁支护分为一、二、三、四、五区.支护五区与一栋17层高的住宅楼相邻，该住宅楼基础形式为筏板，埋深为 5 m，与基坑边相距5.6 m，该区采用排桩进行支护，桩径为1.0 m，桩间距为1.2 m，桩长为23 m，依托地锚和既有住宅楼的门墩在冠梁处设置了3道预应力锚索.本文选择五区为研究对象，在基坑开挖前进行了监测点的布置，见图 1.在施工过程中，基坑分4步开挖到底，每次挖深分别为3 m、3 m、5 m、3 m，基坑开挖施工过程见图2.图1 基坑平面及监测布置Fig.1 foundation pit plane and monitoring arrangement图2 基坑分析断面（单位：mm）Fig.2 foundation pit analysis section（unit: mm）2 修正摩尔库伦模型采用MIDAS-GTS/NX有限元分析软件，该软件提供了修正摩尔库伦模型（Modified Mohr Coulomb Model，以下简称MMC模型），该模型是对Mohr-Coulomb模型的优化，弹性模量可以根据加载和卸载设置不同的值，故更适用于基坑开挖数值模拟研究.模型具体参数见表1.118841粉土细砂砂砾-23 m第1步开挖第2步开挖第3步开挖第4步开挖59333辽宁工程技术大学学报（自然科学版） 第40卷136 表1 MMC 模型参数 Tab.1 MMC model parameters参数说明参考值/(kN ∙m -1）ref 50E标准三轴试验中的割线模量 试验获取 E 主固结仪加载中的切线模量 试验获取 E三轴试验卸载/重新加载模量试验获取 c ′ 有效黏聚力 试验获取 φ′ 有效内摩擦角试验获取 K 0 正常固结下的侧压力系数1-sin φ′[8] ψ 最终剪胀角 φ′-30° ν 泊松比 工程地质手册[9]R f 破坏比 0.9σref 参考压力由基坑深度确定m 应力水平相关幂指数0.5[10] α 帽盖形状系数 根据K 0得到 β帽盖硬化系数根据E 得到修正摩尔库伦模型中模拟结果的不同受ref 50E 、ref oedE 、refur E 这3个模量影响较大，现将3个模量的关系表示分述如下：对于自然状态土体，一次加载时的应力应变行为是高度非线性的，不同的模量取决于应力水平的不同.因此用参数E 50表示一次加载的应力相关模量[11]，代替初始模量E 作为小应变的切线模量. E 50为3ref5050refcot ()cot p mpc E E c σφσφ+⋅=+⋅， （1） 式中，ref50E 是与参考应力σref 相对应的参考割线模量，MPa ；实际的模量取决于较小的主应力σ3，即三轴试验中的有效围压，MPa ，故MMC 模型的参考应力σref 用某一σ3确定值来表示，根据不同的σ3相对应的方程联立，从而准确得出参考割线模量ref50E .见图3，硬化型破坏曲线取15%轴向应变所对应的偏应力值为破坏值q f ，软化型破坏曲线偏应力峰值点为破坏值q f ，1/2破坏值与原点的连线斜率即为参考割线模量ref50E.图3 三轴单次加载试验应力应变Fig.3 stress-strain of triaxial single loading testMMC 模型突出了两种主要的硬化类型，即剪切硬化和压缩硬化.剪切硬化是用来模拟加卸载过程中不可逆应变的主要偏载现象.卸载再加载应力路径采用另一种应力相关模量[11]ur E 为3refur ur ref cot ()cot p m pc E E c σφσφ+⋅=+⋅，（2）式中，ref ur E 为卸载再加载的参考加卸载模量，见图4，两条直线斜率表示峰值应变前后加卸载模量，可以发现，加卸载模量大小不受轴向应变影响，只与参考应力σref 相对应.由于剪切模量被广泛使用，加卸载模量应用较少，所以将剪切模量与加卸载模量相联系.在胡克的弹性理论中，弹性模量E 和剪切模量G 之间的换算公式为21E G υ=+（).由于E ur 是一个真正的弹性模量，因此可以写成ur ur ur 21)E G υ=+（，其中G ur 是弹性剪切模量.偏应力q /k P a轴向应变/%图4 三轴加卸载试验应力应变Fig.4 stress-strain of triaxial loading and unloading test压缩硬化是用来模拟在固结仪加载和各向同性加载中由于初次压缩而产生不可逆塑性应变的现象.与基于弹性的模型相比，弹塑性MMC 模型不涉及三轴模量E 50和E oed 之间的固定关系.因此E oed [11]为3refoed oed ref cot ().cot p m pc E E c σφσφ+⋅=+⋅ （3）图5 固结试验p-εFig.5 stress-strain curve of consolidation test如图5，固结试验得到p-ε曲线，将曲线拟合后，求得在每一级轴向载荷下的切线斜率，即为在该级参考应力下的参考切线模量，因为压缩实验是无侧限试验，该级应力参考大主应力，参考应力σref 用某一σ1确定值来表示，根据不用的σ1相对应的方程联立，从而准确得出参考切线模量.0.020.04 0.06 0.08 0.10轴向应变ε50150250350450轴向载荷p /k P a土1 土2土1拟合曲线土2拟合曲线第2期胡建林，等：修正摩尔库伦模型下的深基坑变形数值分析1373 参数获取及模型说明3.1 模拟参数取值分析为获得模拟参数，根据工程要求进行了室内三轴与固结试验.三轴试验采用固结不排水试验，围压设置分别为50 kPa、100 kPa、150 kPa、200 kPa、250 kPa，根据模型参数获取需要同时进行卸载再加载试验.前人在一些深基坑工程中固定参考应力σref 为100 kPa进行参数分析及数值模拟，但是14 m 的深基坑显然选用一个参考应力是不合适的.为了进行更加精确的分析，取0～3 m深的土层的参考应力σref为50 kPa，3～5.5 m深的土层的参考应力σref为100 kPa，5.5～8 m深的土层的参考应力σref为150 kPa，8～11 m深的土层的参考应力σref为200 kPa，11～14 m深的土层的参考应力σref为250 kPa.上述试验在每一种参考应力下求得的参数以及规范建议值见表2、表3.表2 土体物理力学性质指标Tab. 2 physical and mechanical properties of soil地层编号土体名称干密度/(g∙cm-3)含水质量分数/%容重/(kN∙m-3)泊松比ν孔隙比e内摩擦角φ′/(º)粘聚力c′/(kPa)膨胀角ψ/(º)1 粉土 1.80 17.4 180.300.78224.236.62 细砂 1.825 3.2 18.250.260.78 40 103 砂砾 2.00 200.210.7244.8 14.8表3 MMC本构模型参数Tab.3 MMC constitutive model parameters地层编号土体名称基坑深度/m侧压力系数K0幂指数m压缩模量E S/MPa割线模量ref50E/MPa切线模量refoedE/MPa卸荷弹模refurE/MPa 0～3 3.78 5.52 6.49 13.43～5.5 6.6 7.33 8.2 30.21 粉土5.5～8 0.60 0.59.0 9.16 9.3 78.92 细砂8～11 0.36 0.5 10 10.12 10.58 151.53 砂砾 11～14 0.30 0.5 40 40 40 850 3.2 模型说明进行数值模拟材料设定时，围护结构及锚索均按弹性材料考虑，围护桩采用梁单元，锚索采用植入式桁架单元.细砂土几乎没有粘聚力，输入0.3 kN/m2的值以避免分析发生错误.未开挖前应施加土体在自重状态下的初始应力场，并将初始位移置零.由于混凝土和土体的变形模量有很大的差异，为了模拟围护结构与土之间的共同作用，必须在两者之间设置析取接触面单元[12].布置与实际情况相同大小的均布载荷模拟基坑附近的建筑载荷.有限元模型底边与竖向边界都为全约束，为避免约束影响，模拟深基坑水平向长度是基坑深度的7倍，约100 m，竖向深度为基坑深度的3倍，约50 m，有限元模型见图6.图6 有限元模型Fig.6 finite element model将上述求得的岩土参数分别代入MC模型、MMC模型进行数值模拟分析.4 结果分析通过探究深基坑不同深度处设置不同参考应107 m7 m5m辽宁工程技术大学学报（自然科学版） 第40卷138 力的必要性以及MMC 模型的优越性，采用3种方法进行数值分析，分别为单一参考应力下的 MMC 本构模型计算、不同参考应力下的MMC 本构模型计算、MC 本构模型计算，分别将3种计算结果与深基坑实际监测变形位移进行对比分析，得到不同施工步骤下的变形值，见图7、图8.其中MC 表示采用摩尔库伦本构模型模拟基坑开挖的变形情况，MMC 表示采用修正摩尔库伦本构模型在不同参考应力下模拟基坑开挖变形情况，MMC100表示采用修正摩尔库伦本构模型在100 kPa 单一参考应力条件下模拟基坑开挖变形情况，实测表示现场基坑开挖测得的地表沉降和水平位移情况.4.1 地表沉降变形分析图7分别表示为第1、2、3、4步开挖后地表沉降情况.-0.6-0.4-0.200.2距排桩距离/mMC MMC MMC100实测20406080100（a ）第1步（b ）第2步-8-6-4-20距排桩距离/mMCMMC MMC100实测20406080100（c ）第3步 （d ）第4步图7 不同施工步骤开挖完成后地表沉降对比Fig.7 comparison of surface settlement under different construction steps由图7可知，在实际开挖过程中，基坑周边地表沉降随着距基坑边壁距离不断增大而呈现类似对勾曲线形式，即沉降先增加后减小最后逐渐趋于零，其中在距基坑边壁10 m 左右地表沉降达最大值.由图7对比发现，基坑周边地表随基坑不断开挖沉降逐渐增大，此过程中MC 模型预测值与实测值相差较大，发生最大沉降处距基坑边壁距离与实测值相差近5 m ，计算沉降影响距离是实测沉降影响距离的2倍左右；但MMC 模型预测沉降与实测值相差不大，且沉降规律较为吻合.详细对比MMC 和MMC100预测沉降结果可知，MMC100在预测开挖前期沉降时要略微小于MMC ，但在开挖后期MMC 和MMC100预测沉降几乎一致，说明低围压下使用100 kPa 较大参考应力是不合适的，依据土压力理论可知，深基坑越深，围压越大，参考应力也随之增大才会与实际情况相符合.总的来说，使用不同参考应力下的MMC 本构模型进行沉降预测更具参考价值. 4.2 排桩变形分析图8分别表示第1、2、3、4步开挖后排桩水平位移情况.第2期 胡建林，等：修正摩尔库伦模型下的深基坑变形数值分析139（a ）第1步 （b ）第2步（c ）第3步 （d ）第4步图8 不同施工步骤开挖完成后排桩位移对比Fig.8 comparison of pile displacement in different construction steps由图8可以看出，当每一施工步完成后，排桩水平位移沿桩顶到桩底呈现先增大后减小最后趋于零的趋势，其中在距地面6 m 深左右排桩水平位移达到最大值.由图8对比发现，排桩水平位移随基坑开挖而逐渐增大，此过程中MC 模型计算位移值与实测位移值相差较大，且发生最大水平位移处排桩深度与实际深度不符；但MMC 模型计算位移与实测值相差不大，且位移规律较为符合.详细对比MMC 和MMC100计算值可知， MMC100在计算开挖前期水平位移时要略微小于MMC ，但在开挖后期MMC 和MMC100计算水平位移值几乎一致，说明低围压下使用100 kPa 较大参考应力是不合适的，深基坑越深，围压越大，参考应力也随之增大较能符合实际情况.总的来说，使用不同参考应力下的MMC 本构模型进行水平位移计算更具参考价值.5 结论考虑土体模量和应力相关的影响，理想的弹塑性本构模型（MC 模型）预测结果与实测位移变形存在较大的差距.采用MMC 模型，进行排桩变形和地表沉降的数值模拟，将单一参考应力与不同参考应力下的MMC 本构模型计算的地表沉降和水平位移与深基坑实际监测变形位移进行对比分析，得到以下结论：（1）在地表沉降计算上，基坑周边地表沉降随着距基坑边壁距离不断增大而呈现先增加后减小最后逐渐趋于零的趋势，其中在距基坑边壁 10 m 左右地表沉降达最大值.基坑周边地表随基坑开挖沉降逐渐增大，此过程中MC 模型预测值与实测值相差较大，发生最大沉降处距基坑边壁0.05 0.10 0.15水平位移/mm0.511.5水平位移/mm-25MC MMC MMC100实测MC MMC MMC100 实测MC MMC MMC100实测-5-10-15-20-25深度/m0-5-10-15-20深度/m0水平位移/mm-251230 -5-10-15-20深度/m246水平位移/mmMC MMC MMC100 实测-5-10-15-20-25深度/m辽宁工程技术大学学报（自然科学版）第40卷 140距离与实测值相差近5 m，计算沉降影响距离是实测沉降影响距离的2倍左右，但MMC模型预测沉降与实测值相差不大，且沉降规律较为吻合.（2）在排桩水平位移计算上，排桩水平位移沿桩顶到桩底呈现先增大后减小最后趋于零的趋势，其中在距地面约6 m深基坑位移达到最大值. MC模型计算位移计算值与实测位移值相差较大，且发生最大水平位移处排桩深度与实际深度不符，但MMC模型计算位移与实测值相差不大，且位移规律较为符合.（3）对比MMC和MMC100计算沉降结果可知，MMC100在计算开挖前期沉降位移时要略小于MMC，但在开挖后期MMC和MMC100预测变形几乎一致，说明低围压下使用100 kPa较大参考应力是不合适的，依据土压力理论可知，深基坑越深，围压越大，参考应力也随之增大才会与实际情况相符合.总的来说，使用不同参考应力下的MMC本构模型进行沉降预测更具参考价值.参考文献（References）：[1] 李飞,徐劲,张飞,等.渗流作用下深基坑开挖抗隆起破坏数值模拟[J].地下空间与工程学报,2017,13(4):1 088-1 097.LI Fei,XU Jin,ZHANG Fei,et al.Numerical simulation of anti-uplift failure of deep foundation pit excavation under seepage[J].Journal of Underground Space and Engineering,2017,13(4):1 088-1 097. [2] 陈小雨,袁静,胡敏云,等.相邻深大基坑安全距离理论分析与数值模拟[J].地下空间与工程学报,2019,15(5):1 557-1 564,1 572.CHEN Xiaoyu,YUAN Jing,HU Minyun,et al.Theoretical analysis and numerical simulation of safety distance of adjacent deep and large foundation pit[J].Journal of Underground Space and Engineering,2019,15(5):1 557-1 564,1 572.[3] YUAN Changfeng,YU Haojie,YUAN Zijin,et al.Numerical simulationof impact caused by construction of high-rise building upon adjacent tunnels[J].Geotechnical and Geological Engineering, 2019,37(4):3 171-3 181.[4]WANG Jianxiu,FENG Bo,YU Haipeng,et al.Numerical study ofdewatering in a large deep foundation pit[J].Environmental Earth Sciences,2013,69(3):863-872.[5] 曾超峰,薛秀丽,郑刚.软土区基坑预降水引起支护墙侧移的典型参数影响研究[J].岩土力学,2017,38(11):3 295-3 303,3 318.ZENG Chaofeng,XUE Xiuli,ZHENG Gang.Study on the influenceof typical parameters on lateral displacement of retaining wall caused by predewatering of foundation pit in soft soil area[J].Rock and Soil Mechanics,2017,38(11):3 295-3 303,3 318.[6] 赵秀绍,艾成刚,王旭,等.砂性土深基坑开挖与支护变形监测的数值分析[J].河南科技大学学报(自然科学版),2014,35(6):61-65+8.ZHAO Xiushao,AI Chenggang,WANG Xu,et al.Numerical analysis of excavation and support deformation monitoring of deep found-ation pit with sandy soil[J].Journal of Henan University of Science and Technology(Natural Science Edition),2014,35(6):61-65,8.[7] 王卫东,王浩然,徐中华.基坑开挖数值分析中土体硬化模型参数的试验研究[J].岩土力学,2012,33(8):2 283-2 290.WANG Weidong,WANG Haoran,XU Zhonghua.Experimental study on parameters of soil hardening-g model in numerical analysis of foundation pit excavation[J].Rock and Soil Mechanics,2012,33(8):2 283-2 290.[8] 罗耀武,凌道盛,陈云敏,等.环形超深基坑围护结构受力变形特性分析[J].岩土力学,2011,32(02):617-622.LUO Yaowu,LING Daosheng,CHEN Yunmin,et al.Analysis of stress and deformation characteristics of ring super deep foundation pit envelope[J].Rock and Soil Mechanics,2011,32(2):617-622.[9] 《工程地质手册》编写委员会.工程地质手册[M].北京:中国建筑工业出版社,2018.[10] 徐中华,王卫东.敏感环境下基坑数值分析中土体本构模型的选择[J].岩土力学,2010,31(1):258-264,326.XU Zhonghua,WANG Weidong.Selection of soil constitutive model in numerical analysis of foundation pit under sensitive environment[J].Rock and Soil Mechanics,2010,31(1):258-264,326.[11] 李建伟,陈沅江,杜金龙.砂卵石地层基坑开挖土体本构模型辨识研究[J].地下空间与工程学报,2013,9(2):223-228.LI Jianwei,CHEN Yuanjiang,DU jinlong.Identification of soil constitutive model for sand and pebble foundation pit excavation[J].Journal of Underground Space and Engineering, 2013,9(2):223-228.[12] 俞建霖,龚晓南.深基坑工程的空间性状分析[J].岩土工程学报,1999(1):24-28.YU Jianlin,GONG Xiaonan.Spatial character analysis of deep foundation pit engineering[J].Journal of Geotechnical Engineering, 1999(1):24-28.。
美国经济微观经济学杂志
American Economic Journal Microeconomics美国经济微观经济学杂志A journal of the American Economic Association美国经济学会的杂志May 2021 VOLUME 4, NUMBER 2ArticlesTo Review or Not to Review? Limited Strategic Thinking at the Movie Box OfficeAlexander L. Brown, Colin F. Camerer, and Dan LovalloIdeologues Beat IdealistsSambuddha Ghosh and Vinayak Tripathi正文在此目录下目录题目： Contracting with Heterogeneous Externalities 50到76页Shai Bernstein and Eyal WinterIgnorance Is Bliss: An Experimental Study of the Use of Ambiguity and Vagueness in the Coordination Games with Asymmetric PayoffsMarina Agranov and Andrew SchotterContracting in Vague EnvironmentsMarie-louise Vier∅On the Robustness of Anchoring Effects in WTP and WTA ExperimentsDrew Fudenberg, David K. Levine, and Zacharias ManiadisContractual and Organizational Structure with Reciprocal AgentsFlorian Englmaier and Stephen LeiderIncentive Schemes, Sorting. And Behavioral Biases of Employees: Experimental EvidenceIan Larkin and Stephen Leider正文第59页到67页C. Optimal Ranking of Cyclic TournamentsIn the previous section, we demonstrated that optimal full implantation contracts are derived from a virtual tournament among the agents in which agentｉ beats agent ｊif∅∅(j)<∅∅(i)).However, the discussion was based on the tournament being acyclic. If the tournament is cyclic, the choice of the optimal DAC contracting scheme (i.e., the optimal ranking) is more delicate since Lemma 1 does not hold. Any ranking is prone to inconsistencies in the sense that there must be a pair ｉ,ｊ such that ｉ is ranked above ｊ although ｊ beats ｉ in the tournament. To illustrate this point, consider a three-agent example where agent ｉ beats ｊ,agent ｊbeats ｋ, and agentｋbeats ｉ.The tournament is cyclic and any ranking of these agents necessarily yields inconsistencies. For example, take the ranking｛ｉ,ｊ，ｋ｝,which yields an inconsistency involving the pair(ｋ，ｉ)since ｋbeats ｉandｉis ranked above agent ｋ.This applies to all possible rankings of the three agents.The inconsistent ranking problem is similar to problems in sports tournaments, which involve bilateral matches that may turn out to yield cyclic outcomes. Various sports organizations (such as the National Collegiate Athletic Association-NCAA) nevertheless provide rankings ofteams/players based on the cyclic tournament. Extensive literature in operations research suggests solution procedures for determining the “minimum violation ranking” (e.g., Kendall 1962); Cook and Kress 1990; and Coleman 2005) that selects the ranking for which the number of inconsistencies is minimized. It can be shown that this ranking is obtained as follows. Take the cyclic (directed) graph obtained by the tournament and find the smallest set of arcs such that reversing the direction of these arcs results in an acyclic graph. The desired ranking is taken to be the consistent ranking (per Lemma 1) with respect to the resulting acyclic graph.One may argue that this procedure can be improved by assigning weights to arcs in the tournament depending on the score by which team ｉbeats teamｊand then look for the acyclic graph that minimizes the total weighted inconsistencies. In fact this approach goes back to Condor cet’s (1785) classical voting paper in which he proposed a method for ranking multiple candidates. In the voting game, the set of nodes is the group of candidates, the arcs’ directions are the results of pairwise voting, and the weights are the plurality in the voting. The solution to our problem follows the same path. In our framework arcs are not homogeneous and so they be assigned weights determined by the difference in the bilateral externalities. As in Condorcet’s (1785) voting paper, we will look for the set of arcs such that their reversal turns the graph into an acyclic one. While Young (1988) characterized Condorcet’s (1785) method axiomatically, our solution results form a completely different approach, i.e., the design of optimal incentives to maximize revenues.Formally, we define the weight of each arc(ｉ,ｊ) ∈ A by t(i,ｊ) =∅∅(∅)-∅∅(∅).Note that weights are always nonnegative as an arc(ｉ,ｊ) refers to a situation in which ｊfavors ｉmore thanｉfavorsｊ. Hence t(ｉ,ｊ) refers to the extent one-sidedness of the externalities between the pairs of agents. If an inconsistency in the ranking arises due to an arc(ｉ,ｊ), then this implies that agent ｊprecedes agent ｉdespite the fact that ｉbeats ｊ. Relative to consistent rankings, inconsistencies generate additional costs for the principal. More precisely, the principal has to pay an additional t(ｉ,ｊ) when inconsistency is due to arc(ｉ,ｊ) ∈A.For each subset of arcs S = {(∅1,∅1), (∅2,∅2),…，(∅∅,∅∅)} we definet(S)=∑∅(∅,∅)(∅,∅)∈∅,Which is the total weight of the arcs in S .For each graph G and subset of arcs S we denote by G＿s the graph obtained from G by reversing the arcs in the subset S. Consider a cyclic graph G and let S* be a subset of arcs that satisfies the following:(i)G-s* is acyclic.(ii)t(S*)≤t(S) for all S such that G-s* is acyclic.Then, G-s* is the acyclic graph obtained from G by reversing the set of arcs with the minimal total weight, and S* is the set of pairs of agents that satisfies inconsistencies in the tournament ranking of G –s*. Proposition 4 shows that the optimal ranking of G is the tournament ranking of G –s* since the additional cost from inconsistencies, t(S*), is the lowest.PROPOSITION 4: Let (N,w,c) be a participation problem with a cyclic tournament G. Let φ be the tournament ranking of G-s*. Then, the optimal full implementation contracts are the DAC with respect toφ.In the symmetric case, the principal cannot exploit the externalities among the agents, as ∅∅∅∅∅=0, and the total payment made by the principal is identical for all rankings. This can be seen to follow from Proposition 4 as well by noting that the tournament has two-way arcs connecting all pairs of agents, and t(i,j)=0 for all i ,j and t(S) is uniformly zero. An intriguing feature of the symmetric case is that all optimal contracting schemes are discriminative in spite of the fact that all agents are identical.COROLLARY 4: When the externalities structure w is symmetric then all DAC contracts are optimal. We can now provide the analogue version of Proposition 3 for the cyclic case. In this case, the optimal ranking has an additional term ∅∅∅∅∅∅∅=t(S*) representing the cost of making the tournament acyclic, i.e., the cost borne by the principal due to inconsistencies. PROPSITION 5: let (N, w, c) be a participation problem. Let ∅∅∅∅∅be the principal’s optimal cost of a full implementation contract. Then ∅∅∅∅∅=n ·c - 12⁄(∅∅∅∅+∅∅∅∅∅) +∅∅∅∅∅∅∅. Corollary 3.1 still holds for pairs of agents that are we not in S*. More specifically, if we increase the level of asymmetry between pairs of agents that are outside S*, we reduce the total expenses that the principal incurs in the optimal contracting scheme.Ⅲ.ExtensionsIn this section, We discuss the implications of the assumptions we made so far .We demonstrate that the optimal contracts remain optimal if we assume sequential participation choices when the principal desires to implement participation in a subgame perfect equilibrium with the property that each player has a dominant strategy on the subgame that he plays. In addition, We show that even when the outside option is affected by the agents' participation choices, the construction of the optimal contracts remains unchanged. We demonstrate that when contracts can be contingent on the participation of a subset of the agents, then the optimal contracts are closely related to the analysis above. Our analysis is valid in more general setups in which externalities can be either negative or positive. Moreover, the solution is also relevant to nonadditive externalities structures.A.Sequential Participation DecisionsWe first point out that our analysis applies to any sequential game except for one of perfect information, i.e., when each player is fully informed about all the participation decisions of his predecessors. Indeed, this extreme case of perfect information is a strong assumption as agents rarely possess the participation decisions of all their predecessors. Any partial information environment implies that some actions are taken simultaneously, and therefore thedivide-and-conquer contracting scheme and the virtual tournament apply.Nevertheless, it is interesting to point out that our analysis is also relevant to the extreme case of perfect information. Consider a game in which players have to decide sequentially about their participation based on a given order. Suppose that the principal wishes to implement the full participation in a subgame perfect equilibrium with the additional requirement that each player has a dominant strategy on the subgame in which he has to play. It is easily verified that the optimal contracting scheme in this framework is the DAC applied to the order of moves; i.e., the first movingplayer is paid c and the last player is paid c-∑∅∅∅∈∅(j).Under this contracting scheme each playerhas a dominant strategy on each subgame. Assume now that the principal can control the order of moves (which he can do by making the offers sequentially and setting a deadline on agents' decisions).Then the optimal sequential contracting scheme is exactly identical to the one discussed in previous sections for the simultaneous case. If the principal suffices with a standard subgame perfect equilibrium(without the strategy dominance condition ) , then the optimal contracting scheme will allow him to extract more and he will pay c-∑∅∅∅∈∅(j) to all agents.B. Participation-Dependent Outside OptionsIn many situations, nonparticipating agents are affected by the participation choices of other agents. Consider the case of a corporate raider who needs to acquire the shares of N identical shareholders to gain control(similar to Grossman and Hart 1980).If the raider is enhancing the value of the firm when he holds a larger stake in the firm, then selling shareholders impose positiveexternalities on nonparticipating agents. If the raider gains private benefits from the firm which will decrease its value, then selling shareholders induce negative externalities on the nonparticipating agents.In this section we consider the case in which the agents' outside option is partly determined by the agents who choose to participate. For a given group of agents P ≤N who participate, we define the outside option of nonparticipants as c+∑∅∅∅∈∅(j).In the former analysis we assumed η=0.22 Segal (2003) defines externalities as increasing (decreasing) when an agent is more (less) eager to participate when more agents participate. In our setup, eagerness to participate isidentity-dependent. When η≤1, we say that agents are more eager to participate when highly valued agents choose to participate. If η>1 ,the benefit of nonparticipation outweigh the benefits of participation when highly valued agents choose to participate; hence agents are less eager to participate. In Segal's terminology, the former case is equivalent to increasing externalities, while the latter is equivalent to decreasing externalities.Following the analysis of Proposition 1, if v is an optimal full implementation contracting scheme then it is easy to verify that under the current setup, v is a DAC of the form: V=(c, c-(1-η)∅∅2(∅1),…,c -(1-η)∑∅∅∅∅(∅∅ )),Where φ=(∅1,∅2,…,∅∅) is an arbitrary ranking. Instead if η>1, the participation problem is identical to a standard participation problem(with fixed outside option) where externalities are (1-η)∅∅(j)<0. In these negative externalities problems the DAC mechanism does not apply and theoptimal scheme requires that the principal reimburse the agents for their total burden, i.e., c-(1-η)∑∅∅∅(j),which is a positive number whenever the outside option and ∅∅(j) are positive. Finally, the case of η=1 corresponds to an environment of no externalities at all and the optimal scheme requires simply to reimburse agents for their outside option. We can summarize with the following proposition:PROPOSITIN 6: LET ( N, w,∅∗) be a participation problem where ∅∅∗=c+∑∅∅∅∈∅(j) and P ≤N is a group of participating agents. LET G (N,A)be the equivalent tournament. The optimal full implementation contracts are given as follows: (i) For η<1,DAC contracts with respect to the optimal ∅∅∅∅∅∅∅;23(ii) For η≥1, the optimal mechanism pays agent I the payoff c-(1-η)∑∅∅∅(j),Which is exactly c, wherever η=1.Note that one could consider a different case in which the outside option of agents in a linear function of the externalities agents induce. Also in this case, asymmetry improves the principal’s rant extraction.C. Contingent contractsOur model assumes that the principle cannot write contracts that make a payoff to an agent contingent on the participation of other agents. Under such contracts the principal could extract the total surplus form positive externalities among the agents. We find such contracts not very descriptive. Based on the data used by Gould, Pashigian, and Prendergast (2005)which consists of contractual provisions of over 2500 stores in 35 large shopping malls in the United States, there is no evidence that contracts make use of such contingencies. Shopping malls are a natural environment for contingent; the fact that these contracts are still not used makes it likely that in other, more complicated settings such contracts are exceptional as well. The theoretical foundation for the absence of such contracts is beyond the scope of this paper. However, one possible reason for their absence is the complexity of such contracts, especially in environment s where participation involves long-term engagement and may be carried out by different agents at different points in time. We point out that if partial contingencies are used, i.e., participation is contingent on a subset of the group , our model and its analysis remain valid. Specifically, for each player i,let ∅∅⊆N be the contingency set, i.e., the set of agents whose participation choice can appearin the contract with agent i. Let T= (∅1,∅2,⋯,∅∅) summarize the contingency sets in the contracts. The optimal contract (when contingencies are not allowed). More precisely, let w be the original matrix of externalities. Denote by∅∅ the matrix of externalities obtained from w by replacing ∅∅(∅)with zero whenever j∈∅∅. lemma 6.1 in the appendix shows that the optimal full implementation contracting scheme is as follows: agent I gets c if one of the agents j ∈∅∅does not participate ,i.e., the contingency requirement is violated. If all agents in ∅∅participate,then agent I gets the payoff ∅∅(∅,∅∅,∅) - ∑∅∅(∅),∅∈∅∅where∅∅(∅,∅∅,∅) is the payoff for agent I for the participation problem (N,∅∅,∅ ) under no-contingencies.D.mixed externalities structureSo far we have limited our discussion to environments in which agents’ participation positively affects the willingness of other agents to participate. However, in many situations this is not the case, such as in environments of congestion. Traffic, market entry, and competition among applicants all share the property that the larger the number of agents who participate, the lower the utility of each participant. The heterogeneous property in our framework seems quite descriptive in some of these examples. In the conetxt of competition it is clear that a more qualified candidate/firm induces a large negative externality. It is also reasonable to assume, at lease for some of these environments, that the principal desires a large number of participants in spite of the negative externalities that they induce on each other.In proposition 7, we demonstrate that in order to sustain full participation as a unique Nash equilibrium under negative externalities the principal has to fully compensate all agents for the participation of the others.PROPOSITION 7: let (N, w, c)be a participation problem with negative externalities. Then optimalfull implementation contracts v are given by ∅∅=∅+∑|∅∅∅≠∅(∅)| and v is unique.Naturally, real-world multi-agent contracting problems ay capture both positive and negative types of externalities. In social events, individuals may greatly benefit from some of the invited guests, while preferring to avoid others. In a mall, the entry of a new store may benefit some stores by attracting more customers, but impose negative externalities on its competitors.Our analysis of the mixed externalities case is based on the following binary relation. We say that an agent I is nonaverse to agent j if∅∅(∅)≥0, and we write it as I≥j. we will assume that ≥ is symmetric and transitive, I.e., i≥j ⇒ j≥I and if i≥j and j≥k then i≥k. note that this assumption does not imply and constraint on the magnitude of the externalities, but just on their sign. While the symmetry and transitivity of the nonaverse relation seem rather intuitive assumptions, not all strategic environments satisfy them. These assumptions are particularly relevant to environments where the selected population is partitioned into social, ethnic, or political groups with animosity potentially occurring only between groups but not within groups. We analyze a specific example of this sort of environment in Section IV.It turns out that the optimal solution of participation problems with symmetry and transitivity of the nonaverse relation is derived by a decomposition of the participation problem into two separate participation problems: one that involves only positive externalities, and the other that involves only negative externalities. This is done by simply decomposing the externalities matrix into a negative and a positive matrix. In the following proposition we show that the decomposition contracting scheme, a contract set that is the sum of the two optimal contracts of the two decomposed participation problems, is the optimal contracting scheme for the mixed externalities participation problem.Proposition 8: consider a participation problem (N, w, c).let (N,w+, c) be a participation problem such that ∅∅+(∅)=∅∅(∅) if ∅∅(∅)>0 and ∅∅+(∅)=0 if ∅∅(∅)<0 ,and let ∅+be the optimal full implementation contracts of (N,∅+ ,c). Let (N,∅− , 0) be a participation problem such that ∅∅−(∅)=∅∅(∅)if ∅∅(∅)<0and ∅∅−(∅)=0 if∅∅(∅)≥0, and let ∅−be the optimal full implementation contracts of (N, ∅−,0). Then, the decomposition contracting scheme v=∅++∅− induces a unique full participation equilibrium. Moreover, if agents satisfy symmetry and transitivity with respect to the relation, v is the optimal contracting scheme.Proposition 8 shows that the virtual popularity tournament discussed in earlier sections plays a central role also in the mixed externalities case as it determines payoffs for the positive component of the problem. When symmetry and transitivity hold, the principal can exploit the positive externalities to reduce payments. In this tournament, i beats j whenever(i)∅∅(∅)≥0and∅∅(∅)≥0, and (ii)∅∅(∅)>∅∅(∅). Note that, under the nonaverse assumptions, the principal provides complete compensation for the agents who suffer from negative externalities, as in the negativeexternalities ca se. Finally, it is easy to show that equivalently to Proposition 5, the principal’s cost of achieving full implementation in a mixed externalities setting is equivalent to the positive externalities setup, except that now the principal has to add the compensation for the negative externalities.E. Nonadditive PreferencesWe propose here an extension of the model in which preferences are no longer assumed to be separably additive. Using an iterative procedure that makes use of the solution for the additive case allows us to narrow down the set of potential optimal incentive contracts, even when no structure is assumed.A participation problem is described by a group of agent N and their outside option is equal to c, as noted previously. We assume a general externalities structure, which is composed of the nonadditive preferences of the agents over all subsets of agents in the group N. More specifically, for each i,∅∅:2∅{∅}→R. The function ∅∅(∅)stands for the benefit of agent I from the participation with the subset S ⊆N. We normalize v(φ)=0. The condition of positive externalities now reads: for each i and sunsets S,T such that T⊂S we have ∅∅(∅)≥∅∅(∅).Arguments similar to those used in Proposition 1 show that the optimal contracting scheme that sustains full participation as a unique equilibrium also satisfies the divide-and-conquer property. Hence, the optimal contracts rely on the optimal ranking of the agents.We leave the detailed description of the procedure to the proof to the Proposition 9. Instead, we provide an example to illustrate the basic ideas.A Simple Example. -Consider a four-agent example. Given that the optimal solution is DAC for any ranking of agents φ= {∅1,∅2,∅3,∅4}, the DAC contracts with respect to ranking φ are (c,c-∅∅2(∅1),∅−∅∅3(∅1,∅2),∅−∅∅4(∅1,∅2,∅3 )). Instead of identifying the optimal ranking.We apply an iterative procedure of N-1 steps to eliminate rankings that we infer cannot be optimal. Our starting point is the set of all possible ranking of the agents; in this example there are 24 such ranking.1→ 2↑ ↗↘↓3 → 4Step 1:Let’s assume that the bilateral externalities ∅∅(∅)between the agents result in the corresponding acyclic graph described below.Therefore the tournament yields the unique consistent ranking for step one when Φ1= (3,1,2,4).We argue that any ranking that orders the first two agents in a way that contradicts their relative ranking in Φ1 cannot be the optimal ranking. To see this, consider the ranking (4,2,1,3),which is consistent with Φ1 with respect to the relative ranking of agents 4 to 2.We can immediately construct a cheaper ranking by reversing the position of the first two agents, and keeping the position of the remaining agents e=ranked lower in the same order. Hence, we can eliminate (4,2,1,3) from the set of potential optimal ranking. Applying this logic to the entire set of potential rankings we are left with 12 potential rankings; i.e., the optional ranking of the original problem must start with any of the following pairs:(3,1),(3,2),(3,4),(1,2),(1,4),(2,4).Step 2:We now proceed to the second iteration in which for each agent located the first position we construct a graph that is based on the bilateral relations conditional on the participation of the first agent .In particular, we consider the case in which agent 1 is ranked first and build the graph based on agents’ preferences conditional on the participa tion of agent 1;i.e.,the externalities matrix is given by (∅∅(∅)=∅∅(∅,1)|j∈{2,3,4}).Let’s assume that preferences take the following forms:∅2(3,1)>∅3(2,1);∅2(4,1)>∅4(2,1);∅3(4,1)>∅4(3,1).Since the graph is acyclic the unique consistent ranking of the second iteration, conditional on agent 1 being first, is φ2|1=(4,3,2). Again, we require rankings to be consistent with φ2|1.For example, ranking(1,2,4,3)cannot be optimal sinc e (2,4,3) is not consistent with φ2|1 and transposing the order of 2 and 4 we get ranking(1,4,2,3),which is cheaper. While there are six ranking in which agent 1 is ranked first, we can immediately eliminate three that do not agree with φ2|1 and we are left with {(1,4,2,3),(1,4,3,2),(1,3,2,4)}.However, these rankings must agree with the constraints from the previous step. This is not the case for ranking (1, 3, 2, 4),as we can transpose the orderof 1 to 3 and get a cheaper mechanism; thus we can eliminate it as well.26Hence,if the optimal ranking starts with agent 1 it must be followed by agent 4 ranked second. Rather than discussing the construction of cases where agents 2 and 3 are ranked first, we continue to explore the case where agent 1 is ranked first and proceed to step 3.Step 3:In this iteration we repeat and construct the graph based on agents 2 and 3’s preferences, conditional on the participation of agents 1 and 4.Let’s assume that ∅2(3,1,4)<∅3 (2,1,4);hence φ3|1,4={2,3}.Thus, the only ranking that can be optimal in the original problem conditional on agent 1 being first is (1, 4, 2, 3).General Result.-The example above illustrates our procedure for generating the optimal incentive contracts can also be used iteratively to eliminate no optimal rankings, when we impose no structure on agents’ preferences.The start ing point is the set of all agents’ rankings. We proceed with an iterative procedure of N-1 steps; at each step rule out possible rankings by constructing a graph that is based on the bilateral preferences of agents conditional on the participation of agents ranked about them. We assume that in each step the resulting graph is acyclic and thus generates a unique consistent ranking. We eliminate rankings that are inconsistent with the step’s consistent ranking or with the constraints imposed in the previous step. The formal description of this iterative procedure is provided in the proof of Proposition 9.PROPOSITION 9: Let (N, c) be a participation problem with nonadditive preferences, for which all tournaments in the iterative procedure are acyclic. Then, the set of surviving ranking is nonempty and includes the optimal ranking.Proposition 9 demonstrates that the fundamental logic underlying our analysis of additive externalities also underlies our construction, while taking into account the complex structure of externalities among agents.Ⅳ .Group Identity and SelectionIn this section we consider special externalities structures to demonstrate how the selection stage can be incorporated once we have solved the participation problem. Assume that the externalities take values of 0 or 1.In this environment an agent either benefits from the participation of peer or gains no benefit. We provide three examples of group identities in which the society is partitioned into two groups and agents have hedonic preferences for members in these groups. We demonstrate how the optimal contracting scheme proposed in previous sections may affect the selection of the planning of the initiative.American Economic Association。
JCS公司CADR实验室标准指示文件CO-WI-109_Smoke_CADR_Correlation_PR1[1]
![JCS公司CADR实验室标准指示文件CO-WI-109_Smoke_CADR_Correlation_PR1[1]](https://img.taocdn.com/s3/m/ba73eb1bde80d4d8d15a4f39.png)
1.PURPOSE1.1.The purpose of this procedure is to align the Clean Air Delivery Rate (CADR) calculations of JardenConsumer Solutions (JCS) suppliers to the calculations of Intertek (ITS) in Cortland, New York.2.SCOPE2.1.This procedure provides clarifications to the ANSI Method for Measuring Performance of Portable HouseholdElectric Room Air Cleaners (ANSI/AHAM AC-1-2006), specifically the ability to remove smoke particulate from the air. This ability is measured by an air cleaner’s Clean Air Delivery Rate (CADR) for smoke.2.2.This procedure also provid es information to align JCS suppliers’ smoke CADR test conditions, test method,and maintenance procedures with that of ITS.2.3.Excerpts have been taken from the ANSI/AHAM AC-1-2006 (and highlighted with a boarder).Additional detail has been provided, along with pictures in some cases, to assist in duplicating what isbeing done at ITS in Cortland, New York.3.PROCEDURE3.1.ROOM CONSTRUCTION / EQUIPMENT3.1.1.Test Room “Chamber”3.1.1.1.Test Room Construction3.1.1.1.1.Proper creation and maintenance of the testing environment is as important as the testprocedure. Below are guidelines for construction of the room that the smoke CADR testwill be conducted in.3.1.1.1.2.An electrical outlet will be on the floor in the middle of the room near where the aircleaner will be placed during testing.3.1.1.1.2.1.This outlet should be able to be controlled from outside of the room.3.1.1.1.2.2.Voltage to be held within 120VAC +/- 1VAC and 60Hz +/- 1Hz (or per rating labelrated voltage and frequency +/- 1VAC and +/- 1Hz).3.1.1.1.3.The room should be sealed so that there is minimal air flow into and out of the roomduring testing and preparation for testing.3.1.1.1.4.The paint used on the walls, ceiling and floor should be washable.3.1.1.2.Test Room Layout3.1.2.Test Equipment3.1.2.1.Fans(ANSI/AHAM AC-1-2006 – Page 23, Annex A)3.1.2.1.1.Ceiling Fan (Figure 1) is a high volume fan used to mix the room during smokeparticulate (contaminant aerosol) generation.3.1.2.1.2.Reconditioning Fan is part of the system used to achieve the required room conditions(humidity, temperature, etc.) for testing.3.1.2.1.3.Recirculation Fan (Figure 1) is a fan capable of producing between 300 and 400 cfm andused for the purpose of maintaining a homogeneous environment within the chamberFigure 13.1.2.2.Table Stand(ANSI/AHAM AC-1-2006 – Page 23, Annex A)3.1.2.2.1.This table stand (Figure 2) will be used when testing “Table Type” air cleaners as definedin ANSI/AHAM AC-1-2006 - Page 2, Section 3.1.2.Figure 23.1.2.3.Cigarette Smoke Generator (Figures 3a and 3b)(ANSI/AHAM AC-1-2006 – Page 4)3.1.2.3.1.The air flow forcing the smoke particulate into the room must be able to be adjusted inorder to control the burn rate of the cigarette. This can be done by increasing the air flowthrough the “Air Inlet” or decreasing the air flow by opening the “Air Bypass Valve”.Figure 3a (Outside Test Room)Figure 3b (Inside Test Room)3.1.2.4.Aerosol Spectrometer (ANSI/AHAM AC-1-2006 – Page 27)3.1.2.4.1.This device is used for measuring particle size and concentration in the room. It willcalculate the concentration based only on particulate in the size range listed below.3.1.2.5.Cigarette Smoke Diluter (ANSI/AHAM AC-1-2006 – Page 28)3.1.2.5.1.This device is used for reducing the concentration of cigarette smoke by a known factor toa level suitable for measurement.3.1.2.5.2.If the aerosol spectrometer is not able to accurately measure the smoke particulateconcentration in the room at all stages of testing, a diluter may be used to reduce theconcentration by a known factor so that the spectrometer can accurately measure thesmoke particulate concentration.puter3.1.2.6.1.Should have software that monitors the Test Room conditions and calculates the smokeCADR.3.1.3.Please refer to ANSI/AHAM AC-1-2006 for all remaining test room construction and equipmentdetails.3.1.3.1.Equipment list with recommended suppliers and model numbers can be found on page 27.3.1.3.2.At the release date of this procedure, Intertek (ITS) Cortland, New York had updated theirequipment. For the best test procedure alignment, ITS recommends the following replacementequipment:3.1.3.2.1.Recirculation Fan: PSC Blower (Model #1TDR9)3.1.3.2.2.Cooling/Dehumidifying Equipment: EAS Evaporator coil (Model #FZRP0Z4H06G)3.1.3.2.3.Reheater: Is not used by ITS3.1.3.2.4.Voltage Regulator/Watt Transducer: California Instruments Power Supply (Model#3001IX)3.1.3.2.5.Dust Generator: Is not used for smoke CADR testing3.1.3.2.6.Dust Neutralizer: Is not used for smoke CADR testing3.1.3.2.7.Dust/Pollen Particle Counter: Is not used for smoke CADR testing3.1.3.2.8.Cigarette Smoke Monitor: TSI (Model #3340)3.1.3.2.9.High Sensitivity Laser Aerosol Spectrometer Probe: PMS (Model #HSLAS2)3.1.3.2.10.Pollen Generator: Is not used for smoke CADR testing3.1.3.2.11.Watt Meter: Yokogawa (Model #WT210)3.2.SET UP3.2.1.Test Room Conditioning3.2.1.1.Temperature – Relative Humidity Reconditioning Loop3.2.1.1.1.In order to achieve the temperature, humidity and particulate concentration test conditionsrequired in Section 4 of the ANSI/AHAM AC-1-2006 (Page 5), air is filtered andrecycled using the Reconditioning Loop system shown in Figure 4 below.Figure 4ing the Air Conditioning Blower in figure 4, air is drawn through the two Return Air Damperson the floor and up to the Humidifier/Dehumidifier.3.2.1.3.Air travels through a series of filters to achieve the particulate concentration level required fortesting and through the air conditioning unit and heater to reach the temperature required.3.2.1.4.Air recirculation is stopped when all test conditions are achieved in the Test Room.3.2.1.5.Dampers (Figure 5) are closed to restrict the flow of air through the Reconditioning Loop system.All dampers are closed during testing.Figure 53.2.1.6.Sticky Mat3.2.1.6.1.ITS places a sticky mat outside the Test Room door to minimize contaminants that arebrought into the room. These mats can be purchased at .3.2.2.Cigarette Preparation and Storage (ANSI/AHAM AC-1-2006 – Annex C)3.2.2.1.It is important to properly store test cigarettes. Improper storage will result in unacceptable burnrates, unacceptable particulate concentration in the test room and invalid tests.3.2.2.2.ITS purchases the cigarettes for testing from the supplier below3.2.2.3.If it is not possible to obtain the “2R4F” cigarettes from this supplier, TBD brand is recommended.3.2.3.Burn In3.2.3.1.Burn In is the process whereby air purifier test samples are prepared for testing.3.2.3.2.First, the filter is removed from the unit.3.2.3.3.Second, the air purifier is run for 48 hours.3.2.3.4.Finally, the filter is installed back into the air purifier in preparation for testing.3.2.4.Please refer to ANSI/AHAM AC-1-2006 for all remaining test set up requirements.3.3.TESTING PROCEDURE3.3.1.Natural Decay Measurement (ANSI/AHAM AC-1-2006- Page 7, Section 5.1)3.3.1.1.Purpose:3.3.1.1.1.Natural Decay is the natural reduction of particulate in the test room.3.3.1.1.2.Conducting Natural Decay will allow the calculation of the “Na tural Decay Rat e” in thetest room.3.3.1.1.3.This rate will later be used to calculate the smoke CADR according to:3.3.1.2.Preparation3.3.1.2.1.Cleaning3.3.1.2.1.1.Prior to every Natural Decay Measurement, the Test Room and all equipment in theTest Room (including the Smoke Generator Outlet tube - Figure 3b) should becleaned with compressed air. Failure to conduct this maintenance at acceptableintervals will result in invalid measurements.Section 4.6.2. is shown below for convenience3.3.1.2.2.Air Purifier Test Sample3.3.1.2.2.1.The “highest air cleaning mode” is the highest fan setting.3.3.1.2.2.1.1.Note: the air cleaner will be powered off during Natural DecayMeasurement.3.3.1.2.2.2.The testing location of the air cleaner is defined by ITS using a rectanglepermanently drawn next to an electrical outlet on the floor (Figure 6).Figure 63.3.1.2.2.3.Guidelines for Air Cleaner Placement (Unless otherwise required by JCS)3.3.1.2.2.3.1.2-Filter Tower Air Cleaner: Place on the floor during testing.3.3.1.2.2.3.2.1-Filter Tower Air Cleaner: Place on table (Figure 2) during testing.3.3.1.2.2.3.3.1-Filter Desktop Air Cleaner: Place on the table during testing.3.3.1.2.2.3.4.All Console Air Cleaners: Place on the floor during testing.3.3.1.2.2.3.4.1.Note: The table is placed inside the rectangle on the floor3.3.1.2.2.4.Air Cleaner Orientation3.3.1.2.2.4.1.For air cleaners which have air flowing out in a specific direction, this airflow shall NOT be pointed toward the Aerosol Spectrometer.3.3.1.2.2.4.2.ITS always directs the air flow out 90 degrees away from the particlemonitor (See Figure 7)Figure 73.3.1.3.Procedure3.3.1.3.1.Fan Operation3.3.1.3.1.1.Ceiling Mixing Fan (Figure 1)3.3.1.3.1.1.1.As the Test Room conditions are being brought closer to thetemperature and humidity targets(described in 3.2.1.4.), turn on theCeiling Mixing Fan and measure the particulate concentration per above.3.3.1.3.1.1.2.Creating a log file will confirm when the background particulate target androom conditions have been reached.3.3.1.3.1.1.3.The Ceiling Mixing Fan will later be turn off one minute after the initialparticulate concentration is met.3.3.1.3.1.2.Recirculation Fan (Figure 8)3.3.1.3.1.2.1.Location and horizontal orientation of the Recirculation Fan is one of themore critical variables of CADR. If the Recirculation Fan is positionedcorrectly, an air cleaner test sample should have the same smokeCADR on the floor as it would on the Table Stand (within +/-2CADR).3.3.1.3.1.2.2.The Recirculation Fan will be turned on once the smoke generator beginsto input smoke particulate into the room and will remain on throughout thetest.3.3.1.3.1.2.3.Operating the Recirculation Fan will serve to create a homogeneousenvironment where the smoke particulate is evenly distributed throughoutthe room so that the smoke CADR calculated can be representative of thewhole room, instead an area of high particulate concentration or lowconcentration.Figure 83.3.1.3.2.Cigarette3.3.1.3.2.1.The test Cigarette should be taken from the short term storage as described in 3.2.2of CO-WI-109 and hung inside the Cigarette Smoke Generator (3.1.2.3. of CO-WI-109) and shown in Figure 3a.3.3.1.3.2.2.Once the test conditions are reached per 5.1.4.1. above, immediately light theCigarette and control its burn rate by adjusting the air flow as described in 3.1.2.3.1.until the required smoke particulate concentration is reached. If done properly, theCigarette should burn for 45 seconds to reach the target concentration.3.3.1.3.2.3.Note: For even cigarette burning, roll the cigarette back and forth between yourfingers while lighting it with a lighter. This will prevent the cigarette from burningmore quickly on one side.3.3.1.3.2.4.Once the initial concentration is reached, turn off the air supply and close theChamber Valve (Figure 3a) to cut off the supply of smoke into the room.3.3.1.3.2.5.This cigarette smoke particulate concentration data will be used to calculate theNatural Decay Rate discussed below.3.3.1.3.3.Natural Decay Rate Calculation3.3.1.3.3.1.Calculations are performed per ANSI/AHAM AC-1-2006 – Page 16, Section 8 andAnnex D3.3.1.3.4. CADR Calculation is performed after Smoke Particulate Removal Measurement.3.3.2.Cigarette Smoke Particulate Removal Measurement (ANSI/AHAM AC-1-2006- Page 8, Section 5.2)3.3.2.1.Purpose3.3.2.1.1.This procedure will allow the calculation of the “Total Decay Rate” when operating theair cleaner in the Test Room.3.3.2.1.2.This rate will later be used to calculate the smoke CADR using the equation from note3.3.1.1.3 of CO-WI-109.3.3.2.2.Preparation3.3.2.2.1.Follow the cleaning guidelines from 3.3.1.2.1.3.3.2.2.2.The test sample should already be in place with the appropriate setting per 3.3.1.2.2.3.3.2.3.Procedure3.3.2.3.1.Follow the Fan Operation guidelines from 3.3.1.3.1. until the required room conditionsare achieved.3.3.2.3.2.Then follow the procedure details below.3.3.2.3.2.1.This cigarette smoke particulate concentration data will be used to calculate the TotalDecay Rate discussed below.3.3.2.3.3.Total Decay Rate Calculation3.3.2.3.3.1.Calculations are performed per ANSI/AHAM AC-1-2006 – Section 8, Page 16 andAnnex D.3.3.2.4.Please refer to ANSI/AHAM AC-1-2006 for all remaining test procedure details.3.3.3.CADR Calculation3.3.3.1.Please refer to ANSI/AHAM AC-1-2006, Page 18, Section 8.4. for all CADR calculation details.3.4.MAINTENANCE3.4.1.Purpose3.4.1.1.Maintenance is required to be performed in order to consistently meet the required Test Room testconditions. Failure to conduct this maintenance at acceptable intervals will result in invalid tests.3.4.2.Procedure3.4.2.1.Daily Cleaning (ANSI/AHAM AC-1-2006- Page 32 Annex C)3.4.2.1.1.Make note only of procedures related to smoke CADR testing.3.4.2.2.Maintenance & Calibration Procedures (ANSI/AHAM AC-1-2006- Page 32 Annex C)4.DEFINITIONS4.1.None4.2.5.RECORDS5.1.The following information is required5.1.1.Results of all tests conducted must be provided to JCS and stored for two years.6.RELATED DOCUMENTS6.1.ANSI/AHAM AC-1-20067.APPROVAL1.REVISION HISTORYRevision X - XX/XX/XX –Reviser’s Name – Detailed Explanation of change。
雅思阅读同义词表
雅思阅读同义词替换(剑八TEST 4)Cambridge 8 TEST 41. middle-year education=lower secondary school 中学2. format=pattern n.格式3. less successful student=struggler 差等生4. key=contributing factor=important=major=significant=critical n.关键5. achievement=attainment=progress=breakthrough=accomplishment n.成就6. spacious=largely=big=huge=vast=enormous=immense adj.广阔的7. adapt=accessible=get used to=become/grow accustomed to=adjust to v.适应，可接近的8. careful=elaborate=conscientious=thorough=meticulous=methodical adj.仔细的，精心的9. supplementary=assist=additional=extra=further=added=spare=more=another n.补充，帮助10. effort=hard work=work at=push yourself=labour n.努力11. correct answer=accuracy n.精确12. imbalance=disorder=unequal=disproportionate n.不平衡，紊乱13. no longer respond=resistance=fight against 抵抗14. cost=financial outlay=spend=charge=fare=rental=toll n.支出15. innate=built-in adj.先天的16. immunity=resistance n.免疫力17. entail=involve v.包含18. circumstance=system n.环境，系统19. feed on=prey on 以…为食20. blight=plague v.破坏21. wipe out=eradicate=get rid of=abolish=scrap=do away with=eliminate 根除22. plague=infest=troublesome v.折磨23. compare=determination of variation=contrast=liken=make a comparison=draw an analogy=draw a parallel v.对比24. criterion=identification=standard=scale n.标准，识别25. compatible=use both method=well-matched=be made for each other=be a perfect match /pair/couple=be right for=be ideally suited adj.兼容的26. specimen=individual n.标本27. container=plastic or glass tube n.容器28. wet=marshy=soaked=waterlogged=awash adj.湿的29. habitat=area=the environment=ecosystem=ecology n.栖息地30. pitfall=trap n.陷阱31. little time and effort is required=minimal maintenance and intervention 最小程度的维修与介入32. pesticide: a chemical substance used to kill insects and small animals that destroy crops n.杀虫剂33. preservative: a chemical substance that is used to prevent things from decaying, for example food or wood n.防腐剂Cambridge 8 TEST 31. building=property=construction n.建筑2. support=back=be behind=in support of=back somebody up v.支持3. financial support=fund=financial aid 资助4. stumbling block=difficulty=trouble n.麻烦5. create=generate=form=produce v.形成6. direct=guide=lead=instruct=give order/instruction v.指导7. beam=laser=ray=glow=glare n.光线，激光8. aim=direct at=purpose=point=idea=objective=goal=target n.目的9. test in real=field test 实地测试10. genius=giftedness / talent / intellectual=intelligence=brains=brilliant=wisdom n.天才11. inherit=run in family=receive=get=be given=be awarded v.继承12. talent=prodigy=skill=ability=craftsmanship=flair=have a knack=a natural ability to do something well n.才能，技能13. lessen=minimize=subside=lighten=relieve=ease=allay v.减少14. significance=supremacy=definition=meaning=sense=connotation n.重要性15. achieve=make=succeed=manage=make progress=accomplish=get results v.达成16. limitation=restricted=disadvantage=drawback=liability=the downside n.限制17. inexorable=inevitable=unstoppable=remorseless adj.无法改变的18. stable=characteristic=constant=steady=fixed=unchanging adj.稳定的19. life span=duration of life 寿命20. biological clock=internal clock 生物钟21. prolong=extend=drag out=spin out v.延伸，延长22. principle=law=conscience=scruples n.原则，法则23. optimal=better=best adj.最佳的24. conserve=save / frugal=reserve=keep back v.节约，保存25. immortality : the state of living for ever or being remembered for ever adj.不朽的26. organism=living thing=life form=wildlife =an animal, plant, human, or any other living thing n.有机的Cambridge 8 TEST 2drastically : extreme and sudden adv.彻底地carry out : subject to : 使服从remain=stay=keep=continue to be=still v.保持detect=inspect=examine=notice=spot=become aware / conscious=note=conserve=perceive v.检查fault=flaw=defect=trouble=bug=virus=be something wrong with=be something matter with n.缺陷，缺点enough=sufficient=adequate=cover=meet somebody's need adj.足够的main=largely=principal=chief=major=key=primary=prime=predominant=core adj.主要的: documentation=written account=evidence=proof n.证明shift=switch=transfer=move=jerk v.转换consistent=lasting=stay the same=constant=unchanging adj.持续的drought=no rain at all=dry=dusty adj.干旱的period=cycle=era=age n.年代random=arbitrary=at random adj.随机的molten=hot=heat=boiling / boiling hot=scalding / scalding hot adj.熔化的intense=strong=passionate=powerful=deep adj.强烈的discover=explore=find / unearth=turn up v.开发，发现pattern=trade / commodity=business n.贸易relate to=associate with=link to / connect to=identify with 联系feeling=emotional response / sensory=a sense of=passion n. 感觉unappreciated=undervalued adj.低估的difficult=elusive=hard / tough=easier said than done adj.困难的，难懂的study=research=analyse=do/conduct research v.研究smell=odour=scent n.气味interpretation=be considered to be=understanding=reading n.理解define=distinguish=tell the difference v.使明确damage=impair=break=do/cause damage=scratch v.损害realize=consciously consider=occur to=become aware=sink in=strike=hit=wake up to the fact that v.想到reveal=show=demonstrate=let somebody see=present=expose=let somebody take a look v.显示to be defined=unanswered 无答案的husbands and wives=marriage partner / spouse=couple=newlyweds夫妇linguistic=language n.语言describe=name=express=give a description of=talk about=write about=give an account of=tell of v.描述lack=do not exist=not enough=scarce=inadequate=insufficient=in short supply v.缺乏的do not smell=odorless 没有气味的regard as=consider to 把…认作unpleasant=offensive=horrible / disgusting / revolting=not very nice=nasty adj.极讨厌的certain=some=a measure of adj.一些correspond=be consist of=coincide=match up v.一致relevance n.关联float=afloat v.浮动Cambridge 8 TEST 11. agree=concur=go along with=fall in with=go with v.同意2. sceptic and advocate=different attitude 不同的看法3. significance=impressive=meaning=sense n.重要性4. meditation: the practice of emptying your mind of thoughts and feelings, in order to relax completely or for religious reasons n.冥想，沉思5. parapsychology: the scientific study of mysterious abilities that some people claim to have, such as knowing what will happen in the future n.通灵学6. environment=condition=light, sound, warmth=situation=circumstance n.环境7. alter=change=revise=make changes v. 改变8. trial=experiment=test n.实验9. success rate=positive result=achievement=progress=breakthrough=accomplishment n.成就10. pick out=identify=recognize=know=tell v.认出，识别11. limit=minimize=maximum=the most=ceiling=cut-off point v.限制12. different=individual=not like=vary=not the same=contrast with=diverse adj.独特的13. invention=device=creation=innovation n.发明，装置14. cold temperature=freezing weather=chilly=frosty=wintry=cold snap adj.寒冷的15. farming=agriculture n.农业16. simultaneous=at the same time=together=at once=at one time adj.同时的17. uniform=equal=homogeneous adj.均衡的18. devise=formulate=invent=create=come up with=make up=conceive=coin=dream up v.创造19. civil=municipal=metropolitan adj.城市的20. divide=split=separate=break up=break down=take apart=take something to piece v. 分开21. new=revolutionary=original=innovation=fresh=novel=be in its infancy adj.新的，革命的22. create=introduce=invent=make sth. do sth.=be the cause=lead to sth. v..发明23. organize=co-ordinate=arrange=set out=put something in order=line up v.组织，使协调24. public event=communal activity 公众、社交活动25. aviation disaster=sky accident=air crash 空难26. prompt=result in=lead to=make somebody do something=cause somebody to do something=lead somebody to do something=motivate=induce somebody to do something v. 导致27. resemble=like=similar=alike=much the same=comparable v.类似28. oversimplify=incomplete=simplistic=generalize=see things in black and white adj. 过于简化的，不完整的29. altitude=from…meters above the ground=height=how high=level n.高度30. zone=airspace=region=area=district=quarter=block=suburb n.区域31. weather=meteorological=climate=condition n.气候32. categorize=class / type=sort=classify=be grouped=grade v.分类33. create=establish=invent=start up=open=set up=found=inception v.创建34. beacon and flashing=light=beam n.灯光35. improve=develop=evolve=get better=catch up=pick up=things are looking up v.发展，进化36. aircraft=plane=by air n.飞机37. average-sized=medium-sized adj. 中等的38. city=metropolitan=urban=town=village=civic=municipal=downtown n.城市39. pendulum : a long metal stick with a weight at the bottom that swings regularly from side to side to control the working of a clock n.钟摆40. coincidental : happening completely by chance without being planned adj.巧合的41. disobey : to refuse to do what someone with authority tells you to do, or refuse to obeya rule or law v.不服从雅思阅读同义词替换(剑七TEST 4)Cambridge 7 TEST 41. large numbers of=tens of thousands of=many 大量的2. large=massive=huge=enormous=vast 巨大的adj.3. resemble=look like=alike=much the same=akin to 相像v.4. foe=enemy=adversary=hostile 敌人n.5. more than=exceed=over=in excess of 超过v.6. decrease=crash=reduction=fall=drop 下降n.7. stop=halt=come to a halt 停止v.8. sufficient=abundant=enough=adequate 充足的adj.9. establish=found=build=set up 建立v.10. be Successful=prosper=do well=succeed=thrive 成功11. recognize=certify=accept=acknowledge承认 v.12. label=display=call=brand=hail 贴标签，命名v.13. adapt=adjust=get used to=become/grow accustomed to 适应v.14. mistake=error=fault=slip=mix-up 错误n.15. keep a check on=monitor=watch=keep an eye on 监视v.16. unexpected=unpredictable=unforeseeable 不可预见的adj.17. generally=in general=in the whole=all in all=all things considered 大体上的adv.18. previously=before=earlier=formerly 先前adv.19. apply=use=make use of=exercise=utilize 应用v.20. due to=because=since=owing to=thanks to=as a result of 因为21. raise=lift=lift up=pick up=scoop up 使…上升v.22. in addition=besides=additionally=too=also=as well 除此之外23. inhabitant=resident=population=citizen=local 居民n.24. collapse=failure=fall 崩塌，失败n.25. set up=establish=found=start=open 建立26. ensure=make sure=make certain=see to it that 保证v.27. assist=help=aid=give a hand=do sth. For 协助v.28. deny=refuse=withhold 否认v.29. permit=allow=let=agree to=authorize 许可v.30. interfere=intrude=disrupt=meddle 干扰v.31. repeat=redo=retake=do sth. again 重复v.32. prevent=stop=restrain=hold back=discourage 阻止v.33. disrupt=disturb=upset=break up 打扰v.34. long-term=chronic=long=lengthy=long-running 长期的adj.35. expose=show=reveal=present=let sb. see 暴露，揭发v.36. intense=strong=passionate=powerful=fervent 强烈的adj.37. random=arbitrary=at random 任意的，随机的adj.38. require=demand=need=call for 要求v.39. fatigue=tiredness=exhaustion=drowsiness 疲劳n.40. manifest=show=reveal=present 显示v.41. concentrate=pay attention=put one's mind on=attentive 专注v.42. produce=make=manufacture=create=fashion 生产v.43. carry out=implement=put sth. into practice=execute 实行v.44. perform=do=conduct=dabble in 执行v.Cambridge 7 TEST 31. cause=reason=factor=origin=root 原因n.2. measure=weigh=time=take=read 测量v.3. route=motorway=highway=expressway 车道n.4. exclude=omit=miss out=leave out=drop 排除在外v.5. renewable=sustainable=recycling=environmentally friendly 可再生的adj.6. exist=there is/are=be found=occur 存在v.7. limit=restrict=constrain=confine=keep to 限制v.8. boundary=border=edge=outskirts=frontier 边界n.9. allow for=make sth. Possible 使…成为可能10. proposal=suggestion=recommendation=proposition 提议n.11. urban=city=town=municipal 城市的adj.12. odour=smell=stench=stink 味道n.13. find one's way=navigate 导航v.14. bearing=position=standing 方位n.15. exchange=share=distribute 分享v.16. waste=unwanted materials=rubbish=garbage=trash 废物n.17. dental=teeth 牙齿的adj.18. priority=preferential=the most important=overriding 优先n.19. encourage=promote=help=support=be supportive 鼓励v.20. explore=look for=discuss=think 探索v.21. factor=cause=reason=root=origin 因素n.22. cultivate=grow=raise 培养v.23. convert=modify=transfer=adapt=customize 转变v.24. digest=take in=absorb=assimilate 消化v.25. preserve=protect=keep=store=keep sth. In storage 保存，保护v.26. monitor=watch=keep an eye on 监视v.27. allocate=distribute=apportion=grant=confer 分配v.28. decline=decrease=reduce=fall=drop 下降v.29. fragile=weak=delicate=breakable=feeble 脆弱的adj.30. upgrade=improve=make sth.better=make improvements 改进，提高v.31. advanced=developed=sophisticated=high-tech 先进的adj.32. sustainable=renewable=recycling=environmentally friendly 可持续的adj.33. evidence=proof=documentation 证据n.34. long-standing=lengthy=long-running=lasting 长期的adj.Cambridge 7 TEST 21. interior=inner=inside 内部的adj.2. change=shift=alter=transfer 改变v.3. establish=build=found=set up=start 建立v.4. official=authority=leader=supervisor 官员n.5. isolated=inaccessible=distant=remote=faraway 隔离的, 边远的adj.6. collapse=fall=fall over=fall down 倒塌v.7. destroy=devastate=wreck=obliterate 毁灭v.8. absorb=digest=take in=assimilate 吸收v.9. severe=serious=stiff=heavy 严重的adj.10. purify=refine=distill 净化v.11. hidden=disguised=concealed=veiled 隐藏的adj.12. decline=decrease=reduce=fall=drop 下降v.13. deteriorate=get worse=go down=decline 变坏v.14. recognize=know=identify=pick out 认出v.15. conclude=summarize=come to/reach the conclusion 得出结论v.16. adapt to=get used to=become accustomed to=adjust to 适应v.17. initiate=start=launch=open=set in motion 开始，发起v.18. refer to=mention=allude to=touch on 提到v.19. identify=name=recognize=diagnose 确定，认同v.20. request=demand=claim=petition=appeal 要求n.21. be divided into=separate=split=break up=break down 分开v.22. consist of=be made up of=be composed of=comprise 由…组成23. hinder=hamper=impede 阻碍v.24. objective=aim=purpose=goal=target 目标n.25. implement=carry on=execute=put sth. Into practice 实行v.26. promote=encourage=help=aid 促进v.27. warn=caution=alert=give sb. a warning 警告v.28. observation post=watchtower 瞭望塔n.29. access=entrance=entryway=way in 通路，进入n.Cambridge 7 TEST 11. rely on=depend on 依靠v.2. avoid=stay away=keep away=steer clear of=make a detour 避免v.3. die out=extinct=disappear=no longer exist 灭绝v.4. hunt=search for=look for=try to find=in search of 打猎v.5. limb=arm or leg=body=organ 四肢n.6. perceive=sense=see=spot=become aware of=observe 感知，感觉v.7. calculate=measure=work out=figure=estimate=access 计算v.8. detection=finding=observation 探测n.9. coin=invent=make=create=come up with 发明，创造v.10. inaccurate=incorrect=wrong=misleading 不精确的adj.11. revision=change=shift=reform=alteration 改进n.12. downward=fall=drop=downhill 下降的adj.13. increasing=soaring=growing=rising 上升的adj.14. primarily=mainly=largely=chiefly=principally 主要地adv.15. due to=because of=as a result of=thanks to=owing to 因为16. decrease=reduce=fall=drop 下降v.17. radical=not traditional=new=unconventional 激进的adj.18. prior to=beforehand=before=in advance=on the eve of 之前19. demanding=difficult=hard=challenging=tough 要求高的，艰难的adj.20. well known=notorious=famous=renowned 著名的adj.21. admit=acknowledge=confess=to tell the truth 承认v.22. be similar to=like=resemble=bear a resemblance to=akin to 相似v.23. result in=lead to=cause=give rise to=bring about 引发，导致24. sophisticated=advanced=high-tech=complex=complicated 复杂的25. address=solve=deal with=handle 处理v.26. imitate=copy=impersonate=follow one's example 模仿v.27. maintain=continue=carry on=keep up=preserve 维持v.28. feed=eat=have=chew=swallow=consume 喂食v.29. illustrate=show=demonstrate=make clear=reflect 说明v.30. memorise=learn=commit something to memory 记忆v.31. conventional=traditional=conformist=conservative 传统的v.32. notice=see=spot=be aware of=be conscious of 注意到v.33. retain=keep=save=hold on to 保持v.34. convince=persuade=win sb. over=satisfy 使确信v.35. spectacular=impressive=imposing=striking=grand 壮观的adj.Cambridge 6 TEST 41. drug company=pharmaceutical company 医药公司n.2. promotion=marketing 营销n.3. increase=escalate=rise=go up=grow 上升v.4. research=study=survey=investigation 研究n.5. work=be an effective way=be useful=help=achieve=succeed=have an effect=happen=turn out 奏效v.6. technique=strategy=skill=expertise=method=way 技术n.7. criticism=judgement=skepticism=disapproval=denunciation 批评n.8. moral=ethical 道德的adj.9. legitimate=have every right to do=legal=right=authorized 合法的adj.10. money=profit=benefit=income=currency 钱n.11. adults=men and women 成人n.12. maternal=mother=female 母亲的adj.13. education=literacy=cultivation 教育n.14. child=infant=kid 孩子n.15. approximately=about=around=nearly 大约adv.16. impressive=greatest=touching=unforgettable 印象深刻的adj.17. programme=campaign=project 项目n.18. common=persistent=normal=usual=ordinary=everyday 常见的adj.19. be halved=decline by 50% 减半20. key=most important=crucial=critical=significant 关键的adj.21. produce=develop=generate=engineer=manufacture 生产v.22. detailed=explicit=specific 细节的adj.23. on its own=alone 自身24. however=but=yet 但是25. self-confidence=assertiveness=confidence 自信n.26. effective=useful=beneficial=good=needed 有效的adj.27. distinguish=recognize the difference=differentiate 区别v.雅思阅读同义词替换(剑六TEST 3)Cambridge 6 TEST 31. teach=educate=cultivate=nature 教育v.2. actor=star 演员n.3. first=initial=early=primary 最早的adj.4. storyline=narrative=plot 故事情节n.5. globe=world 世界n.6. early=first=ancient 早期的adj.7. passing of time=flow of time 时光的流逝8. describe=tell 描述v.9. realistic=achievable 现实的adj.10. target=goal=aim 目标n.11. feedback=comment=advice=criticism 反馈n.12. match to=suit to 合适13. reward=promotion or advancement=prize=benefit 奖励n.14. link to=make something contingent on=associate with=connect with=relate to 联系起来15. achievement=attainment=gain=success 成就n.16. remuneration=payment 酬金n.17. tend to=prone to 倾向于18. feel=perceive=think=find=experience=notice=have an opinion 感觉v.19. participate=be involved in=take part in=join 参加v.20. staff=employee=worker 员工n.21. visible=disclosed=obvious=noticeable 可见的adj.22. clerical worker=clerk 书记员n.23. judge=rate=criticize=assess=evaluate=gauge=appraise 评判v.24. job=work=assignment 工作n.25. delay=slow=prolong=postpone=procrastinate=shelve=put off延后v.26. growing old=ageing 变老27. people=mortal=people=individual 人n.28. life=lifespan 生命29. chance=likelihood=fortune=hope=possibility=opportunity=risk=luck 机会n.30. production=generation=output 产量n.31. theory=hypothesis=guess=guesswork 猜想n.32. focus on=emphasize=aim at=concentrate on 集中于33. short=scarce=limited=insufficient 短缺的adj.雅思阅读同义词替换(剑六TEST 2)Cambridge 6 TEST 21. successfully=spectacularly well=wonderfully 成功地adv.2. people power=local pressure groups 群众力量n.3. commute=travel 通勤v.4. higher=increasing=more 更高的adj.5. income=wealth=salary=wage=payment 收入n.6. beneficial=valuable=profitable=good 有益的adj.7. together=face to face 共同8. refute=not mean=rebut=deny 反驳v.9. accommodation=live=living condition 住宿n.10. usage=use=benefit=profit 用处n.11. averagely good=reasonable but not special 较好的12. limited=minimal 有限的adj.13. move from one to another=adopt one over another 转移14. show=reveal=uncover=indicate=point out=imply 表明15. related=associated 有关联的adj.16. suffer=be afflicted 忍受(病痛)v.17. research=study=investigation=survey 研究n.18. affect=afflict=influence=change 影响v.19. disease=medical complain=illness 病痛n.20. increase=surge=rise=gain=grow=go up=add=escalate 上升v.21. link=correlation=connection=relationship 关系n.22. considerable=significant=substantial=massive=marked大量的adj.23. reduction=drop=concession=fall=decrease 下降n.24. elderly people=old people 老人n.25. independent=self-reliant 自立的adj.26. regular=daily 定期的adj.27. exercise=physical activity 运动n.28. challenging=difficult=tough=demanding 有挑战性的adj.29. decline=deteriorate=reduce=drop=decrease 下降v.30. lonely=emotionally isolated 孤独的adj.31. hand signal=gesture=body language 手势n.32. restricted=limited 有限的adj.33. concept=abstract idea=definition 定义n.34. specific=particular=detailed 特定的adj.35. early=older 早期的adj.36. fulfill=qualify=achieve=keep=satisfy 完成v.37. sufficient=enough 足够的adj.38. quantity=how many=amount 数量n.39. misunderstanding=confusion 误解n.40. prevent=resolve=forbid=stop 防止v.41. poor=lack of=impoverished 贫穷adj.42. newer=later=recent=present 新的adj.43. ancestor=early people=predecessor 祖先n.Cambridge 6 TEST 1exchange=apply something learned in one to others=change 交流v.expertise=skill 专门技术n.employ=analyze=study 使用v.investigation=analysis 调查n.narrow=focus on 缩小范围v.reproduce=copy=replicate=repeat 复制v.funded support=finance 资金n.athlete=sportsmen and women 运动员n.calculate=measure 计算v.event=championship 赛事n.plan=prepare=design 计划v.improve=grow=get better 进步v.trade=economy 贸易n.transport=import or export=deliver 运输v.local=domestic=native=indigenous 当地的adj.weakening=less=reduced=decreased 下降的adj.value=worth=price=credit=use=benefit=profit 价值n.delivery=export or import 运输n.nearby nations=geographic neighbours 近邻n.international=ocean=global=worldwide 国际的adj.shipping=freight 船运n.cargo=freight=goods 货物n.tariff=charge=fee=tax 税费n.landscape=environment=nature=surrounding=circumstance=view风景n.difficult=harsh=demanding=tough=challenging 困难的adj.essential supplies=food and clothing=necessities 必需品n.supply=provision=support 供给n.grow=increase=rise=improve=go up=boost=expand=extend 增长v.respect=credibility=weight=hour=admiration=consideration尊重n.understanding=knowledge 了解n.well-being=health 健康n.impossible=out of the question=unlikely 不可能adj.catch=exploit=capture 抓捕v.surrounding=environment=circumstance 环境n.push to one's limits=test one's limits 挑战极限not unmanageable=can cope with 能处理的present inhabitant=descendant 居民give up=abandon 放弃mainly=heavily=most 主要地visit=venture 参观雅思阅读同义词替换(剑五TEST 4)Cambridge 5 TEST 41. community=organization=group=body团体n.2. fragile=delicate脆弱的adj.3. remote=distant 遥远的adj.4. require=desire=order=command要求v.5. inhabitant=resident=dweller居住者，居民n.6. consequently=thus=accordingly=hence=therefore=as a result 结果，因此adv.7. destination=goal=end point=terminus目的地n.8. throughout=around=wholly=everywhere=end-to-end自始至终，到处，全部adv.9. operate=act=run运转v.10. output=product输出，产品n.11. decline=reduction=fall=slump=decrease=recession 下降n.12. undermine=destroy=damage=hurt=ruin 破坏v.13. revive=renaissance复兴v.14. unusual=rare=strange=uncommon罕见的，不寻常的adj.15. ordinary=standard=common=usual=general普通的,平常的adj.16. fragment=shard=debris=pieces=ruins碎片n.17. break=shatter=crack打碎，打破v.18. interior=inner layer=inside 内部的n. &adj.19. insist=claim=argue=believe=think坚持，坚称v.20. expand=extend=grow=boom=spread out=enhance扩张，扩大v.21. suppress=control=restrain=repress=put down=oppress=inhibit=ban=forbid=stifle 压制v.22. speed up=increase speed=quicken up=accelerate speed加速v.23. examine=analyse=survey=inspect=study=detect=investigate检查，调查v.24. dispute=debate=controversy=disagree=argue争论，争执n.&v.25. detect=analyse=explore=research=survey=investigate=inspect 察觉，发现v.26. claim=say=state=insist=argue=think=believe声称v.27. cue=implication=reminder=hint=evidence提示，信号，暗号n.28. unpredictable=fluctuate=changeable无法预测的adj.29. be referred to as=be known as=be regarded as 被称为30. encourage=induce=trigger=stimulate=boost=inspire鼓励，促使v.31. considerable=plenty=big=major=important数量可观的adj.32. regardless of=despite of=take no notice of 不管，不顾33. adequate=plenty=proper=appropriate=suitable充足的,适当的adj.34. assure=make sure=guarantee=ensure=insure=secure=make certain of保证，确保v.35. suitable=appropriate=proper=adequate=matching 合适的adj.Cambridge 5 TEST 31. outcome=product=result=conclusion=consequence 结果，后果n.2. overcome=win=get over=exceed克服，战胜v.3. insufficient=deficient=shortage=lack=scarcity不足的adj.4. supply=provide=furnish=give 提供v.5. launch=release=project=send=shot=emit 开始，投放v.6. suppose=expect=imagine=guess=speculate=think猜想，设想v.7. detect=perceive=explore=sense发觉，觉察v.8. handicap=difficult=obstacle=hindrance=bar=deterrent 障碍，困难n.9. peer=the people who are at the same age as you, or who have the same type of job, social class etc.同龄人，伙伴n.10. positive=optimistic=uplifting 积极的adj.11. administer=manage=conduct=implement=perform执行，管理v.12. funding=money=funds=financial resource 资金，基金n.13. interact=if people interact with each other, they talk to each other, work together etc. 互动v.14. irrigation=the supplement of land or crops with water 灌溉n.15. sedimentation=the natural process by which small pieces of rock, earth etc settle at the bottom of the sea etc and form a solid layer 积淀n.16. interrupt=break=violate=cut in打断，打扰v.17. process=procedure=method=approach过程n.18. threat=danger=intimidation 威胁n.19. valuable=precious=worthy宝贵的，珍贵的adj.20. construct=build=make=found 建造v.21. blame=to say or think that someone or something is responsible for something bad责备，怪罪v.22. stimulate=encourage=activate=motivate鼓励，刺激v.23. long-term=long-run=long-period长期的adj.24. impact=affect=influence=effect影响v.&n.25. occur=happen=exist=come发生v.26. contain=include=cover=possess 包含v.27. military=battlefield=martial军事的adj.28. separate=disparate=distinct=different分开的，不同的adj.29. vanish=extinct=disappear 消失v.30. consciousness=awareness 意识n.31. ignite=light=inflame点燃v.32. encompass=include=contain=cover包含，围绕v.33. reckon=think=suppose=believe=imagine=expect=feel认为v.34. widespread=universal=extensive=popular=general广泛的，普遍的adj.35. launch=coin=project=release=issue创新，开辟v.36. contemporary=modern-day, present-day同时代的adj.37. potential=possible=underlying=likely=expected=latent 潜在的，可能的adj.38. prospect=expectation=outlook=chance展望，希望n.39. perception=idea=insight=viewpoint感觉，领悟n.雅思阅读同义词替换(剑五TEST 2)Cambridge 5 TEST 21. similar=like=resemble相似的adj.2. derive=originate=come from=stem from起源v.3. impetus=momentum=stimulus=incentive=motivation=encouragement 动机，动力n.4. generate=produce=bring into existence=make=manufacture产生v.5. couple with=and=accompany=with 伴随v.6. factor=reason=element=component=ingredient 因素n.7. unique=have the distinction=distinct=different=extraordinary=special独特的adj.8. advance=progress=development=growth=increase进步n.9. field=domain=territory=industry=sector领域n.10. alternative=substitute=replacement替代物n.11. like=such as=for example=for instance 例如12. resource=material=source资源，来源n.13. limited=restricted=exhaustible=finite有限的adj.14. involve=rely on=contain=comprise 包含，牵涉v.15. current=modern=recent=present最近的adj.16. particular=extraordinary=special=detail=specific=unique特别的，独有的adj.17. draw on=absorb=do with吸收v.18. settle on=make choice of=decide on选定v.19. superiority=advantage=edge=high quality优势n.20. accompany=when=keep company=be associated with 陪伴，伴随v.21. view=belief=opinion=insight=perception 观点n.22. artificial intelligence=reasoning in machine人工智能n.23. involve with=associate with=link to=relate to与…有关联v.24. release=issue=launch=convey=public=deliver 发行，发表v.25. difficult=demanding=hard=tough困难的adj.26. task=job=work=labour 任务，工作n.27. instantly=rapidly=immediately立即地adv.28. react=respond 反应v.29. relate to=depend on=link to=associate with=involve with 与…有关系v.30. subject views=outlook=personal/individual views=personal/individual opinions 主观观点n.31. distort=to change the appearance, sound, or shape of something so that it is strange or unclear; to report something in a way that is not completely true or correct=misinterpret 扭曲，歪曲v.32. figure out=settle=decide=tell=understand 理解，想出v.33. assessment=appraisal=evaluation=estimate=judgment评估，估计v.34. emerge=appear=come forth出现v.35. remain=keep=stay=maintain保持v.36. exploitation=development=utilization=usage利用，使用n.37. foster=cultivate=raise=nurture培养，养育v.38. overtake=catch up=sweep over赶上，压倒v.39. initial=original=premier最初的，开始的adj.40. whereas=however=while=nevertheless=but=yet然而，但是adv.雅思阅读同义词替换(剑五TEST 1)。
CDVN重组狂犬病病毒的毒力及其免疫原性测定
动物医学进展,2019,40(4):21-27Progress in Veterinary MedicineCDV-N 重组狂犬病病毒的毒力及其免疫原性测定文兆海，周海產，翟少华，陈凯云，胡远，简子健*(新疆农业大学动物医学学院，新疆乌鲁木齐830052)摘 要：为了探究CDV-N 重组狂犬病病毒的毒力及对小鼠的免疫效果，将CDV-N 重组狂犬病病毒于BSR 细胞上扩毒培养、浓缩后测定其FFDg 及LD 5o ；将浓缩后的重组病毒液与复合佐剂按一定比例混匀.按不同免疫剂量、不同免疫方式分组免疫接种小鼠，利用ELISA 试剂盒对狂犬病、犬瘟热的特异性抗体进行定 性/定量检测。
结果显示，重组病毒浓缩后的FFD 50值为7.85 logFFD 5o/0.1 mL,LD 5。
值为7.67 logLD 50/0.03 mL ；免疫接种后第14天抗体阳性率达100%,小鼠血清中的特异性抗体IgG 水平随着免疫剂量的递增而递增。
试验结果可为CDV-N 重组狂犬病病毒制备口服弱毒疫苗的进一步研究提供试验数据。
关键词：重组狂犬病病毒；半数荧光灶形成量；半数致死量；免疫；抗体中图分类号：S852.659.5狂犬病是由狂犬病病毒(Rabies virus, RV)引 起的以侵犯中枢神经系统为特征的一种高度致死性 人兽共患传染病⑴幻。
患病动物的唾液中含有大量的RV, —般通过咬伤的方式，RV 经唾液进入伤口 沿着外周神经向中枢神经系统进犯，一旦到达大脑神经中枢,则引发狂犬病°4〕。
而犬瘟热是由犬瘟热文献标识码：A 文章编号：1007-5038(2019)04-0021-07病毒(Canine distemper virus, CDV )引起的病死率高达80%以上的一种急性高度接触性传染病，具有 极强传染性⑸。
目前，预防狂犬病、犬瘟热最为有效的方法就是疫苗接种，在全球范围内应用最广的就是灭活苗。
DNA 疫苗、弱毒活疫苗、活病毒载体 苗大多还处于研发或临床试验中，灭活疫苗虽然安收稿日期:2018-03-12基金项目：国家自然科学基金项目(31360623)作者简介：文兆海(1990-),男，广西北海人，硕士研究生，主要从事兽医分子病理与免疫病理学研究。
分层接种对猪粪厌氧干发酵产气性能及微生物群落结构的影响
第37卷第1期农业工程学报V ol.37 No.1 2021年1月Transactions of the Chinese Society of Agricultural Engineering Jan. 2021 251分层接种对猪粪厌氧干发酵产气性能及微生物群落结构的影响李丹妮1，高文萱1，张克强1，孔德望2，王思淇1，杜连柱1※（1. 农业农村部环境保护科研监测所，天津300191；2.杭州能源环境工程有限公司，杭州310020）摘要：为避免厌氧干发酵酸抑制，提高产气效率，以猪粪和玉米秸秆为发酵原料，采用中温批式试验，在总固体（Total Solid, TS）为20%、接种比为25%的条件下研究分层接种和混合接种对猪粪干发酵厌氧消化性能的影响。
结果表明：2种接种方式下的发酵体系内挥发性脂肪酸（V olatile Fatty Acids,VFAs）均发生明显积累，其中，分层接种在第15天的TVFAs 质量浓度达到33.0 mg/g，之后明显降低，至发酵结束时VFAs消耗殆尽。
混合接种从第15天至发酵结束，TVFAs质量浓度维持在29.2～38.5 mg/g高水平范围内。
分层接种的累积挥发性固体甲烷产率为211.5 mL/g。
高通量测序结果显示，氢营养型产甲烷途径在2种接种方式下均占主导，但分层接种增加了发酵体系中微生物的丰富度和多样性，且群落结构更加稳定。
进一步分析表明，乙酸和pH值是影响厌氧干发酵中微生态结构的主要环境因子。
该研究结果为解除畜禽养殖废弃物酸抑制、提高产气效率提供理论依据与有益借鉴。
关键词：发酵；粪；微生物群落；分层接种；混合接种doi：10.11975/j.issn.1002-6819.2021.01.030中图分类号：X705 文献标志码：A 文章编号：1002-6819(2021)-01-0251-08李丹妮，高文萱，张克强，等. 分层接种对猪粪厌氧干发酵产气性能及微生物群落结构的影响[J]. 农业工程学报，2021，37(1)：251-258. doi：10.11975/j.issn.1002-6819.2021.01.030 Li Danni, Gao Wenxuan, Zhang Keqiang, et al. Influences of layer inoculation on biogas production and microbial community in solid-state anaerobic fermentation of pig manure[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2021, 37(1): 251-258. (in Chinese with English abstract) doi：10.11975/j.issn.1002-6819.2021.01.030 0 引 言近年来，中国的沼气产业发展迅速，已经成为最大的生物质能源产业之一[1]，随着畜禽养殖向集约化、规模化发展方式转变，沼气发酵成为消纳养殖废弃物应用最广泛的有效措施之一[2]。
Cosmic
" #
Our idea is to consider just this theory ( 4) without the Higgs potential (VHiggs (j j) = 0) but in the presence of the Einstein gravity theory with a conformally coupled scalar eld
On the Cosmological Origin of the Homogeneous Scalar Field in Uni ed Theories
V.N.Pervushin, V.I Smirichinski
Joint Institute for Nuclear Research, 141980, Dubna, Russia.
LG (g; A0 ; j o
To nd minimum of the action with the Lagrangian (5), we express it in terms of the conformal invariant variables, marked by (c), extracting the space-scale factor 6] 1
? cr + 0 +
(14)
The geometrical observables of the Friedmann Universe, in comoving frame of reference, are constructed by using the inverse conformal transformation (7) of the dynamical variables and coordinates, including the Friedmann time interval dtF = a0 d and distance DF = a0 Dc 6, 7]. 2
【VIP专享】剑八同义词替换
【VIP专享】剑八同义词替换TEST 11. agree=concur=go along with=fall in with=go with v.同意2. sceptic and advocate=different attitude 不同的看法3. significance=impressive=meaning=sense n.重要性4. meditation: the practice of emptying your mind of thoughts and feelings, in order to relax completely or for religious reasons n.冥想，沉思5. parapsychology: the scientific study of mysterious abilities that some people claim to have, such as knowing what will happen in the future n.通灵学6. environment=condition=light, sound, warmth=situation=circumstance n.环境7. alter=change=revise=make changes v. 改变8. trial=experiment=test n.实验9. success rate=positive result=achievement=progress=breakthrough=accomplishment n.成就10. pick out=identify=recognize=know=tell v.认出，识别11. limit=minimize=maximum=the most=ceiling=cut-off point v.限制12. different=individual=not like=vary=not the same=contrast with=diverse adj.独特的13. invention=device=creation=innovation n.发明，装置14. cold temperature=freezing weather=chilly=frosty=wintry=cold snap adj.寒冷的15. farming=agriculture n.农业16. simultaneous=at the same time=together=at once=at one time adj.同时的17. uniform=equal=homogeneous adj.均衡的18. devise=formulate=invent=create=come up with=make up=conceive=coin=dream up v.创造19. civil=municipal=metropolitan adj.城市的20. divide=split=separate=break up=break down=take apart=take something to piece v. 分开21.new=revolutionary=original=innovation=fresh=novel=be in its infancy adj.新的，革命的22. create=introduce=invent=make sth. do sth.=be the cause=lead to sth. v..发明23. organize=co-ordinate=arrange=set out=put something in order=line up v.组织，使协调24. public event=communal activity 公众、社交活动25. aviation disaster=sky accident=air crash 空难26. prompt=result in=lead to=make somebody do something=cause somebody to do something=lead somebody to do something=motivate=induce somebody to do something v. 导致27. resemble=like=similar=alike=much the same=comparable v.类似28. oversimplify=incomplete=simplistic=generalize=see things in black and white adj. 过于简化的，不完整的29. altitude=from…meters above the ground=height=how high=level n.高度30.zone=airspace=region=area=district=quarter=block=suburb n.区域31. weather=meteorological=climate=condition n.气候32. categorize=class / type=sort=classify=begrouped=grade v.分类33. create=establish=invent=start up=open=set up=found=inception v.创建34. beacon and flashing=light=beam n.灯光35. improve=develop=evolve=get better=catch up=pick up=things are looking up v.发展，进化36. aircraft=plane=by air n.飞机37. average-sized=medium-sized adj. 中等的38.city=metropolitan=urban=town=village=civic=municipal=down town n.城市39. pendulum : a long metal stick with a weight at the bottom that swings regularly from side to side to control the working ofa clock n.钟摆40. coincidental : happening completely by chance without being planned adj.巧合的41. disobey : to refuse to do what someone with authority tells you to do, or refuse to obey a rule or law v.不服从TEST 21.drastically : extreme and sudden adv.彻底地2.carry out : subject to : 使服从3.remain=stay=keep=continue to be=still v.保持4.detect=inspect=examine=notice=spot=become aware / conscious=note=conserve=perceive v.检查5.fault=flaw=defect=trouble=bug=virus=be something wrong with=be something matter with n.缺陷，缺点6.enough=sufficient=adequate=cover=meet somebody's need adj.足够的7.main=largely=principal=chief=major=key=primary=prime=predominant=core adj.主要的:8.documentation=written account=evidence=proof n.证明9.shift=switch=transfer=move=jerk v.转换10.consistent=lasting=stay the same=constant=unchanging adj.持续的11.drought=no rain at all=dry=dusty adj.干旱的12.period=cycle=era=age n.年代13.random=arbitrary=at random adj.随机的14.molten=hot=heat=boiling / boiling hot=scalding / scalding hot adj.熔化的15.intense=strong=passionate=powerful=deep adj.强烈的16.discover=explore=find / unearth=turn up v.开发，发现17.pattern=trade / commodity=business n.贸易18.relate to=associate with=link to / connect to=identify with 联系19.feeling=emotional response / sensory=a sense of=passion n. 感觉20.unappreciated=undervalued adj.低估的21.difficult=elusive=hard / tough=easier said than done adj.困难的，难懂的22.study=research=analyse=do/conduct research v.研究23.smell=odour=scent n.气味24.interpretation=be considered to be=understanding=reading n.理解25.define=distinguish=tell the difference v.使明确26.damage=impair=break=do/cause damage=scratch v.损害27.realize=consciously consider=occur to=become aware=sink in=strike=hit=wake up to the fact that v.想到28.reveal=show=demonstrate=let somebody see=present=expose=let somebody take a look v.显示29.to be defined=unanswered 无答案的30.husbands and wives=marriage partner / spouse=couple=newlyweds夫妇31.linguistic=language n.语言32.describe=name=express=give a description of=talk about=write about=give an account of=tell of v.描述/doc/a816348475.html,ck=do not exist=not enough=scarce=inadequate=insufficient=in short supply v.缺乏的34.do not smell=odorless 没有气味的35.regard as=consider to 把…认作36.unpleasant=offensive=horrible / disgusting / revolting=not very nice=nasty adj.极讨厌的37.certain=some=a measure of adj.一些38.correspond=be consist of=coincide=match up v.一致39.relevance n.关联40.float=afloat v.浮动TEST 31. building=property=construction n.建筑2. support=back=be behind=in support of=back somebody up v.支持3. financial support=fund=financial aid 资助4. stumbling block=difficulty=trouble n.麻烦5. create=generate=form=produce v.形成6. direct=guide=lead=instruct=give order/instruction v.指导7. beam=laser=ray=glow=glare n.光线，激光8. aim=directat=purpose=point=idea=objective=goal=target n.目的9. test in real=field test 实地测试10. genius=giftedness / talent / intellectual=intelligence=brains=brilliant=wisdom n.天才11. inherit=run in family=receive=get=be given=be awarded v.继承12. talent=prodigy=skill=ability=craftsmanship=flair=havea knack=a natural ability to do something well n.才能，技能13. lessen=minimize=subside=lighten=relieve=ease=allay v.减少14.significance=supremacy=definition=meaning=sense=connotati on n.重要性15. achieve=make=succeed=manage=make progress=accomplish=get results v.达成16.limitation=restricted=disadvantage=drawback=liability=the downside n.限制17. inexorable=inevitable=unstoppable=remorseless adj.无法改变的18.stable=characteristic=constant=steady=fixed=unchanging adj.稳定的19. life span=duration of life 寿命20. biological clock=internal clock 生物钟21. prolong=extend=drag out=spin out v.延伸，延长22. principle=law=conscience=scruples n.原则，法则23. optimal=better=best adj.最佳的24. conserve=save / frugal=reserve=keep back v.节约，保存25. immortality : the state of living for ever or beingremembered for ever adj.不朽的26. organism=living thing=life form=wildlife =an animal, plant, human, or any other living thing n.有机的TEST 41. middle-year education=lower secondary school 中学2. format=pattern n.格式3. less successful student=struggler 差等生4. key=contributing factor=important=major=significant=critical n.关键5.achievement=attainment=progress=breakthrough=accomplish ment n.成就6. spacious=largely=big=huge=vast=enormous=immense adj.广阔的7. adapt=accessible=get used to=become/grow accustomed to=adjust to v.适应，可接近的8.careful=elaborate=conscientious=thorough=meticulous=meth odical adj.仔细的，精心的9.supplementary=assist=additional=extra=further=added=spare =more=another n.补充，帮助10. effort=hard work=work at=push yourself=labour n.努力11. correct answer=accuracy n.精确12. imbalance=disorder=unequal=disproportionate n.不平衡，紊乱13. no longer respond=resistance=fight against 抵抗14. cost=financial outlay=spend=charge=fare=rental=toll n.支出15. innate=built-in adj.先天的16. immunity=resistance n.免疫力17. entail=involve v.包含18. circumstance=system n.环境，系统19. feed on=prey on 以…为食20. blight=plague v.破坏21. wipe out=eradicate=get rid of=abolish=scrap=do away with=eliminate 根除22. plague=infest=troublesome v.折磨23. compare=determination of variation=contrast=liken=make a comparison=draw an analogy=draw a parallel v.对比24. criterion=identification=standard=scale n.标准，识别25. compatible=use both method=well-matched=be made for each other=be a perfect match/pair/couple=be right for=be ideally suited adj.兼容的26. specimen=individual n.标本27. container=plastic or glass tube n.容器28. wet=marshy=soaked=waterlogged=awash adj.湿的29. habitat=area=the environment=ecosystem=ecology n.栖息地30. pitfall=trap n.陷阱31. little time and effort is required=minimal maintenance and intervention 最小程度的维修与介入32. pesticide: a chemical substance used to kill insects and small animals that destroy crops n.杀虫剂33. preservative: a chemical substance that is used to prevent things from decaying, for example food or wood n.防腐剂。
普洛麦格 Lumit
G9711, G9712 and G9713中文说明书适用产品目录号：W1151 和 W11522020版 CTM611原英文技术手册TM611Lumit™ FcRn BindingImmunoassay普洛麦格(北京)生物技术有限公司Promega (Beijing) Biotech Co., Ltd 地址：北京市东城区北三环东路36号环球贸易中心B座907-909电话：************网址：技术支持电话：800 810 8133(座机拨打)，400 810 8133(手机拨打)技术支持邮箱：*************************CTM6112020制作1Lumit™ FcRn Binding Immunoassay所有技术文献的英文原版均可在/ protocols获得。
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电子邮箱：*************************1. 产品描述 (2)2. 产品组分和储存条件 (4)3. 使用前 (5)4. Lumit™ FcRn Binding Immunoassay 操作流程 (5)4.A. 制备对照抗体 (7)4.B. 制备样品 (8)4.C. 制备试剂 (8)4.D. Lumit™ FcRn Binding Immunoassay (8)5. 疑难解答 (9)6. 参考文献 (9)7. 相关产品 (10)普洛麦格(北京)生物技术有限公司Promega (Beijing) Biotech Co., Ltd 地址：北京市东城区北三环东路36号环球贸易中心B座907-909电话：************网址：技术支持电话：800 810 8133(座机拨打)，400 810 8133(手机拨打)技术支持邮箱：*************************CTM6112020制作21. 产品描述新生儿Fc受体（FcRn）是一种主要组织相容性复合物（MHC）I类异源二聚体蛋白，由轻链β2-微球蛋白（β2m）和跨膜重链（α-FcRn）组成。
minimal set
Decomposition of a 2D polygon into aminimal set of disjoint primitivesH. Lipson M. ShpitalniAbstractThis paper presents a method based on artificial intelligence (AI) techniques for decomposing a two-dimensional polygoninto a minimal set of disjoint primitives. Decomposition isaccomplished using a search algorithm based on recursivelysplitting the given shape into smaller parts until a primitive isrecognized. The method operates in a primitive-orientedenvironment, where each primitive type must provide three basicmember functions, namely (a) a function for recognizing a shapeas the primitive, (b) a function for suggesting new splittingcurves for a given shape, and (c) a function for optimisticallyestimating the number of primitives required to tile a shape.Optimality in the number of decomposition units can beguaranteed subject to the domain spanned by function (b). Theproposed method produces a hierarchical decomposition of theshape. Examples from a working implementation are shown.IntroductionThe need for converting from Boundary representation (B-Rep) to Constructive Solid Geometry representation (CSG) has arisen in many geometric modelling and image processing applications and has motivated both practical and theoretical interest. Rigid three-dimensional homogeneous solids or two-dimensional shapes may be modelled as sets of compact, regular and semi-analytic points. Requicha [1] describes six families of informationally complete representation schemes. Of these, CSG and B-Rep are most widely used. While transformation from CSG to B-Rep is relatively well understood [2], the reverse is not. The need for B-Rep to CSG conversions arises mainly in solid modelling packages, where alternative representations allow application of various representation-specific technologies, more versatile user-interface options and more compact storage.In general, there are three approaches to the problem of B-Rep to CSG conversion. The first approach converts the boundary to a set of half-spaces joined by Boolean algebra. Such algorithms have been proposed both for two-dimensional polygons [3] and for three-dimensional solids [4, 5]. The second approach describes the object's geometry as the difference between its convex hull and its concavities.1The process is repeated recursively until only convex components remain. These, in turn, are described as a union of half-spaces corresponding to their faces. Such algorithms are applied to two-dimensional shapes [6] and three-dimensional solids [7]. The third approach uses decomposition techniques [8,9]. These can be divided into partitioning methods and covering methods. Partitioning methods subdivide a shape into non-overlapping convex pieces, whereas covering techniques allow overlapping of the components and thus usually take advantage of collinear edges. Tiling problems in combinatorial geometry [10] are also related; however, they usually do not focus on minimal sets or multiple tile types (primitive shapes). Dynamic programming techniques have also been used [11].The approach proposed in this paper can be classified as a partitioning decomposition method. A given two-dimensional polygon is partitioned into a finite set of non-overlapping primitives or subtracted primitives. The partitioning provides a general framework into which various primitives and target functions can be "plugged in". As output, the given polygon is tiled with a set of the given primitives, according to the given target function. The tiling approach provides a form of CSG decomposition of the given shape. Moreover, it can also be used in other applications, such as computing geometrical properties like the area of a polygon while allowing simple manual verification, two-dimensional geometrical disjoint feature recognition, and meshing.In this paper, the basic problem and solution approach are outlined. Then, the algorithm structure and implementation are described in detail, and examples from a working implementation are provided.Problem and solution approachThe goal of the decomposition process is to break down a given convex or concave polygon into a minimal set of predefined primitives. The polygon is constructed from straight line segments arranged in a convex or concave contour. More complex geometries, such as multiple or nested contours, can be decomposed by treating each of their contours separately. The primitives themselves are also polygons with specific properties.Decomposition is achieved by recursively splitting the given shape into smaller parts until a primitive is recognized, as illustrated in Figure 1. Note that although each polygon can be split in an infinite number of ways, the number of topologically different splits is limited. A split is considered topologically different from another split if it creates a different number or arrangement of segments or if the segments exhibit some geometrical regularity such as collinearity or parallelism.2Figure 1. Recursive splitting down to the primitive level.Figure 2 illustrates 16 different split possibilities for a rectangle. The last two are considered different only because they exhibit the parallelism regularity. The splitting problem can therefore be transformed from an infinitely continuous domain into a discrete problem space, making it a combinatorial optimization problem.While the number of options still remains large, various well established AI search techniques can now be applied. For a survey of search techniques, refer to [12,13]. Relevant search methods are described briefly here.Figure 2. (a) 16 topologically different ways to split a rectangle.(b) Two are geometrically (not topologically) special.3Search MethodsSearch is a universal problem-solving technique in artificial intelligence. It systematically explores alternative sequences of steps required for solving a problem. Each step leads from one state to the next in the problem-state domain. All that is required is a set of states, a set of legal operators, an initial state, and a goal criterion. For polygon decomposition, the initial state is the original polygon and the legal operator is splitting. Activating the splitting operator on the initial state produces several alternative new states, which, in turn, may be subject to further splitting. A final state in the decomposition problem is a state where all the "pieces" are identified as primitives, and the goal is to minimize the number of primitives. Figure 3 illustrates this process, from the initial state through generation of intermediate states to the final goal states.Brute force techniquesThe most general search algorithms are termed brute force searches since they do not require any domain-specific knowledge. Thus, for brute force decomposition, two basic functions are required:• A function to provide splitting operators (and execute them)• A function to recognize and count primitives in a solution state.The most important brute force search techniques are breadth-first, depth-first, iterative deepening and bi-directional searches. These techniques differ in time and space complexities, but they will eventually scan the complete problem domain before they can declare the optimal solution. Due to the large number of splitting operators possible in the polygon decomposition problem, however, a full scan is impractical. Heuristic SearchAll brute force searches are inefficient because they are essentially blind searches. They use no knowledge about which nodes (decomposition states) should be expanded next. A heuristic search, in contrast, takes advantage of information available in the problem domain to differentiate between the likelihood of various states to lead to the goal state.This information, often termed a heuristic evaluation function, estimates the distance between two states in the problem domain. The distance can usually be estimated without actually determining the path between the states and can therefore be evaluated at relatively low computational cost. In the polygon decomposition problem domain, a457843Figure 3. Decomposition states leading from the initial polygon toseveral decomposition alternatives.heuristic evaluation function estimates the number of primitives required to tile a given shape without actually finding them.A* Heuristic SearchOne of the most established heuristic search algorithm is A* (A-Star) [13]. In this algorithm, each state is assigned a value corresponding to its likelihood to lead to a solution. This value takes the form f(n) = g(n) + h(n), where g(n) is the actual cost of the path leading from the initial state to node (state) n and h(n) estimates the lowest cost from node n to a final goal state. The search process always selects and expands the state with the lowest f(n). In the polygon decomposition problem, new states are generated by splitting the basic state in various ways. The figure of merit associated with each state f(n) is the number of pieces already identified as primitives g(n) plus an estimation of the number of primitives required to tile the remaining pieces which have not as yet been identified as primitives h(n).A* always finds an optimal path to a goal (lowest cost path) if the heuristic function h(n) does not overestimate the actual cost to the goal [14]. The first solution found is the optimal solution, provided that the cost function f(n) is monotonic, i.e., it is consistent by obeying the triangle inequality of metrics. This requirement ensures that A* will expand paths in non-decreasing order of cost, and thus once A* finds a path to a goal node, it is the lowest cost path.To conclude, the three functions necessary to execute a heuristic search in the polygon decomposition problem domain are as follows:• A function to estimate the number of primitives required to tile a polygon. This function must be monotonic and should never overestimate the real number.• A function to provide splitting operators (and execute them).• A function to recognize and count primitives in a solution state.ImplementationPrimitive member functionsTo facilitate introduction of primitive-specific knowledge, "private" functions are associated individually with each primitive type. In an object-oriented sense, a primitive object must provide three member functions: functions for split-suggestions, functions for heuristic estimation, and functions for primitive identification.The split-suggestions functionThe split-suggestions function proposes how to split the shape. The routine should suggest none, one or more split lines. Primitive-specific information is used to select the most promising possibilities. The following rules are observed:1. All split lines must start at a polygon vertex, thus reducing the number ofsegments in the split pieces.2. Split lines that are collinear with other segments of the polygon boundary arepreferable. This criterion increases the effectiveness of tiling primitives, since a primitive edge may match more than one edge of the polygon.3. Split lines exhibiting some geometrical regularities which also exist in a primitiveare preferable. For example, for a rectangular primitive, split lines creating 90° angles with one or more of the contour segments are preferable. For a trapezoid primitive, split lines parallel to one or more of the contour segments are preferable. A triangle has no preferences in this respect.67(a) (b) (c) Figure 4. (a) Split lines preferred by collinearity. (b) Split lines preferred by 90° criterion. (c) Some split lines suggested by a triangle object.Split line suggestions are "collected" from each of the primitive objects and are considered as operators to advance the current decomposition state in the decomposition problem domain. Figure 4 illustrates some split suggestions. Heuristic estimation functionThe function guiding the heuristic search is the estimation function. This function forecasts the number of primitives necessary to tile a given polygon. It should not overestimate the actual number but should approach it from below as closely as possible. As the estimation approaches the real number, the number of nodes expanded by the heuristic function decreases.If the N -sided polygon is already in the form of a primitive, the estimation function should return "1"; otherwise, at least "2" is necessary. Primitives used to tile a polygon must have at least one edge in common. Consequently, if a primitive with n sides is used as a tile, it may match at most (n -1) segments of the N -sided polygon contour. Therefore, N/(n -1) primitives can be expected, and the minimum number of primitives k necessary to tile a polygon with N sides is at leastk =max 2,N (n −1) æ è ç ö ø ÷if the polygon is not a primitive itself. The assumption that each primitive matches (n -1) segments of the polygon contour is equivalent to the best case and thus ensures that k is not overestimated.The proposed heuristic estimation function is monotonic. Refer again to the N -sided polygon. The estimated number of primitives is given by the above equation. If this polygon is split into two new polygons, the total number of contour segments is increased by at least 2 ( if the split8(a) (b) Figure 5. (a) 4 collinear points require a reduction of 2 in the number of sides. (b) 3 collinear points require a reduction of 1.line coincides with a diagonal of the polygon). The sum of the estimations of both split pieces k1+k2 must therefore be at least k. Since the values of k1 and k2 are rounded upwards, cases where k1 or k2 are not factors of N can only increase the sum k1+k2.Special cases where one or more lines are collinear in the given polygon or in the resulting split pieces must be considered and treated separately. In such cases, a single primitive may simultaneously match more than one line of the contour. This may cause the heuristic function to overestimate the actual number of primitives. To remedy this, collinear lines or collinear points are counted differently. In cases of m )m>2) collinear vertices, the number of lines that may be created using these vertices is (m -1). These (m -1) lines can be matched simultaneously (in the worst case) by one primitive. To ensure that the heuristic function does not overestimate, these (m -1) lines are counted as one, i.e., (m -2) lines must be subtracted from the original N lines of the polygon before k is calculated . In Figure 5 (a), N'=8 but there are 4 collinear points. Thus, (m-2) = (4-2) is subtracted from N , so that N=6. An estimation of tiling with rectangles where n=4 produces the estimation of k = N'/ (n-1) = 6/3 = 2, which is a correct estimation. Similarly, an estimation of triangle tiling of the shape illustrated in Figure 5 (b) is also corrected by this amendment.Primitive IdentificationAll primitive objects must supply a function for identifying a polygon as the primitive. Precise implementation depends on the primitive type, but care must be taken to overcome pathological cases of zero-length lines, subdivided lines and near-accurate angles. Typically, some tolerance is required in the identification.Algorithm stepsGiven an initial polygon to decompose, the decomposition proceeds as follows:1. Compute the cost f(n) of the given polygon and store it in the Open-State list.2. Select the lowest cost state from the Open-State list. Check whether all the piecesare primitives. If so, the optimal solution has been obtained - Stop.3. Obtain splitting suggestions for the lowest cost state from all primitive functions.Merge and eliminate duplicate suggestions. Move the state to theClosed-State list.4. Duplicate the current state, split according to each suggestion in turn, computecost, and store the new states in the Open-State list.5. Go to step 2.This procedure always converges into the optimal decomposition, namely, achieving the minimal number of non-overlapping primitives required to tile the original shape. It is important to note that optimality is guaranteed subject to the options spanned by the splitting suggestions. If a certain subdivision is never suggested, it will never be reached."Plug-in" primitivesThe estimation term in the cost computation is obtained by taking the most optimistic forecast of the estimator functions of all the primitives. A primitive is identified sequentially by calling the identification routine of each primitive, and split suggestions are obtained by merging the suggestions of all primitive split-suggesting functions. That is, addition of a new primitive to the decomposition system involves only the addition of a new primitive object supplying the three member functions.Convergence of the search procedure can be guaranteed only if a goal state is feasible. In the polygon decomposition problem domain, feasibility corresponds to the ability to tile an arbitrary shape with some primitive. To ensure this, a triangular primitive must always be available to the system, and the triangular split-suggestion function must be able to decompose any shape.910Figure 6. Partially duplicate decomposition states.Elimination of duplicate statesOne of the reasons for the large number of decomposition states is the duplication of state configurations. A state duplication occurs under two circumstances. The first case is a consequence of applying the same set of split operators in a different sequence. Figure 3 shows four final decomposition states, each duplicated twice (e.g., state 1 and state 5). The second case is a partial state duplication, where one or more of the pieces in a state appears in another state as well. Here, the decomposition algorithm will "work" on decomposing that specific piece more than once. Such a situation can occur as a result of different sequences, as is illustrated in Figure 6.The first situation stems from the fact that the heuristic search algorithm does not search only states but also paths to states; there are several optimal decomposition states and several paths leading to each. The search algorithm may simultaneously expand several paths that ultimately lead to the same decomposition. In the decomposition problem, however, optimality is a function of the final state and not of the path leading to it. State repetition can be avoided by posing a constraint so that any decomposition state can be reached from only one decomposition path (i.e., one splitting sequence). The constraint is enforced by assigning some arbitrary order to the split operators. The order, for example, can be the chronological order in which the split11 a dab cdec fd a g b hFigure 7. Duplicate decompositions eliminatedby disallowing descending split sequences.operators are first suggested. Once an order is set, the search process should disallow the application of split operators in an order different from their assigned order. This eliminates the possibility of the same state being found by following different paths without missing any decomposition state. Only one sequence of split operators can correspond to any given decomposition state. The number of paths eliminated by this technique is proportional to the number of paths leading to each decomposition state, which is roughly a factorial of the number of split operations.Consider the example shown in Figure 7. The given shape can be initially decomposed using four suggested split lines. These split lines are assigned the letters a, b, c and d , according to some arbitrary order. The shape in the initial state is then decomposed into four new states, each created by splitting the shape in the initial state according to one of the four splitting suggestions. The letter above the new state indicates which split operator was used to obtain that state. Next, two split suggestions are provided for each new state. These split suggestions are also labelled with letters; note however, that split lines previously considered are recognized and assigned their original letter. For simplicity, the heuristic function recommendation is temporarily disregarded and all the new states are expanded. Eight new states are obtained, with the split sequence written above each. Of these eight states, only six are different, and two are duplications. More importantly, the two duplicates are those with a non-ascending lexical order of split operators. If the rule suggested above had been applied, these two states would not have been expanded.The second case of partial-state duplication, as illustrated in Figure 6, does not result in the same set of operators and will not be eliminated by the above technique. It still occurs an exponential number of times and contributes to the overall size of the search domain. The technique used to overcome this difficulty involves the actual identification of the duplicate piece and management of a list of "known pieces". Whenever a contour is encountered for decomposition, it is first matched against the list of known pieces (using a hashing function). If this is not the first instance of the shape, then data on its decomposition will be available. Conversely, if it is the first instance, decomposition continues while back-propagating data to the list and other states using this shape. This technique accelerates the decomposition process but requires space resources that are exponentially proportional to the depth of the search and therefore may be impractical on some machines.ResultsFigure 8 shows decompositions obtained by implementing the proposed decomposition algorithm. The search was accomplished using a triangle, a rectangle and trapezoid primitives (a trapezoid was defined as a quadrilateral with at least two parallel sides). The search algorithm used was iterative deepening A* (IDA*) [12], which is a space-conservative variant of the A* algorithm.ExtensionsFast Time-Limited DecompositionSome applications require real-time solutions to decomposition problems, for example in an interactive system where the user is kept waiting while a shape is decomposed. In such cases, speed may be traded for optimality.In the proposed algorithm, the most prominent time-consuming factor is the number of splitting suggestions. Optimality is sacrificed by selecting only a limited number of the most promising splits (according to the heuristic estimation), thus reducing the search domain. A parameter specifying the maximum number of suggestions taken at each1213(a) (b)(c) (d)Figure 8. Decompositions obtained using the search process.(SG Iris 4D: (a) 2.3 (b) 0.6 (c) 0.8 (d) 1.1 CPU secs.). (Shape (d) adopted from Parry-Barwick et al. [15]). level can be used to govern the solution speed versus deviation from optimality. Figure 9 illustrates a near-optimal decomposition obtained in this way.An important consideration is that because of the mechanism for identifying and storing partial decompositions, the search algorithm can be reactivated with a more elaborate search without actually recomputing parts of the tree already visited. Thus, the decomposition may be improved when more time is available (or "in the background") while minimizing resource waste.Figure 9. Near optimal decomposition obtained under a time limit(SG Iris 4D - 3.7 CPU Seconds).Tie-breakingOne of the important properties of A* is that of all search algorithms using the heuristic estimation function h(n), it expands the fewest number of nodes, up to tie breaking between equal cost nodes [16]. Ties in the cost function f(n) of candidate nodes can have a detrimental effect; at the specific point where a tie occurs, no information is available to distinguish candidate nodes. In the absence of this information, a local breadth-first search is performed. The effect of ties is especially noticeable when the cost function is discrete or of low resolution, and hence the probability of a tie in the cost function is high. In the polygon decomposition problem, the cost function is expressed as an integer estimating the number of primitives necessary for tiling a shape. This function is indeed both discrete and of low resolution (in the range of approximately 1 to n).To improve performance, the search algorithm must be supplied with more information to enable a wiser distinction between equal-cost decomposition states. Provided that this information is only used in tie situations, i.e., the information will never overrun the cost-function recommendation, its usage will not impede the optimality ensured by A*.The tie-breaking information chosen in implementing the polygon decomposition algorithm is split-length. This information describes the total length of lines along which the initial polygon was split, up to the current decomposition state. This function is heuristic; it cannot guarantee selecting the better node in a tie, but ittends to do so. The1415Split line=+Figure 10. External split lines form subtraction operations.split-length value is added as a fraction beyond the integer specifying the number of primitives. The value was scaled so that it always remains a fraction and never overruns the true cost function but only influence ties.One of the advantages of the split-length value as a tie-breaker is that it is simple to calculate and forecast. A conservative forecast is made by multiplying the number of expected primitives by the length of the shortest vertex-line distance in the polygon. Provided that the rules for selecting split suggestions are obeyed, this forecast never overestimates the actual split length. Introduction of this heuristic tie-breaking mechanism has significantly improved search time performance. Non-additive decompositionUntil now, the search algorithm was confined to those split operators that expanded the decomposition state by splitting a shape into two disjoint pieces. Relaxing this requirement provides more decomposition options. Although such relaxation may enlarge the search domain and extend the search process, it also improves the chances of encountering a more efficient decomposition. The scope of splitting operators can be expanded in various ways. In this implementation, the splitting operator scope was enhanced by allowing split lines to run outside the shape. The polygon is split into two parts: one is larger than the original shape and the other is marked by a "negative sign" indicating that it should be subtracted from the larger shape. Figure 10 illustrates such a decomposition.Introduction of this type of external split operator in the proposed decomposition algorithm allows the basic CSG operation of subtraction. While this introduction does increase the search domain size, it does not necessarily increase solution time, as might have been expected. In some cases, execution time was even reduced, perhaps because better opportunities were introduced, causing complete branches of the search tree to be pruned by the A* algorithm.(a) (b)Figure 11. Decomposition obtained using external split line, of shapes in Figure 8. (SG Iris 4D: (a) 3.6 (b) 0.5 CPU secs.)Furthermore, the number of primitives was reduced, thus reducing the maximum depth of the tree. Figure 11 shows results obtained using external split operators. Note that the introduction of external splits has allowed instances of primitive subtraction, thus making it possible for shape 11(a) to be decomposed into six primitives instead of eight (Figure 8(a)) and shape 11(b) to four pieces instead of five (Figure 8(b)). Also note that the decomposition time in these examples has not necessarily increased.Expansion to curved edge and three-dimensional solid decompositionThe proposed algorithm has been described and implemented for a restricted geometrical problem domain consisting of two-dimensional straight-edged polygons. In developing the algorithm, however, no assumptions have been made about this restricted domain. Relaxing the restriction to include curved objects or three-dimensional solids would require a new complexity analysis and the following modifications:• A basic primitive or set of primitives capable of tiling any shape in the domain must be available. If curved shapes are introduced, triangles will not suffice, and curved edge primitives must be provided. For three dimensions, a tetraheder primitive could be used to ensure convergence for planar-faced solids.• More elaborate splitting-suggestion and splitting execution procedures must be provided, according to the type of primitives supported. The basic rules regardingpreferred splitting operators may still be observed (continuation, collinearity,etc.), however, it is expected that execution of the splitting itself, which is a16。
鸟巢英文
国家体育场位于北京奥林匹克公园中心区南部，为2008 年第29 届奥林匹克运动会的主体育场。
工程总占地面积21 公顷，建筑面积258,000m2 。
场内观众坐席约为91000 个，其中临时坐席约11000 个。
奥运会、残奥会开闭幕式、田径比赛及足球比赛决赛在这里举行。
奥运会后这里将成为文化体育、健身购物、餐饮娱乐、旅游展览等综合性的大型场所，并成为具有地标性的体育建筑和奥运遗产。
国家体育场工程为特级体育建筑，主体结构设计使用年限100 年，耐火等级为一级, 抗震设防烈度8 度, 地下工程防水等级1 级。
工程主体建筑呈空间马鞍椭圆形，南北长333 米、东西宽294 米的，高69 米。
主体钢结构形成整体的巨型空间马鞍形钢桁架编织式“ 鸟巢” 结构, 钢结构总用钢量为4.2 万吨，混凝土看台分为上、中、下三层，看台混凝土结构为地下1 层，地上7 层的钢筋混凝土框架- 剪力墙结构体系。
钢结构与混凝土看台上部完全脱开，互不相连，形式上呈相互围合，基础则坐在一个相连的基础底板上。
国家体育场屋顶钢结构上覆盖了双层膜结构，即固定于钢结构上弦之间的透明的上层ETFE 膜和固定于钢结构下弦之下及内环侧壁的半透明的下层PTFE 声学吊顶。
国家体育场工程按PPP( Private + Public + Partnership ) 模式建设，中国中信集团联合体负责国家体育场的投融资、建设、运营和管理。
中信联合体出资42 ％，北京市政府给予58 ％的资金支持。
中信联合体拥有赛后30 年的特许经营权。
国家体育场有限责任公司负责国家体育场的投融资和建设工作，北京中信联合体体育场运营有限公司负责30 年特许经营期内的国家体育场赛后运营维护工作。
国家体育场工程作为国家标志性建筑，2008年奥运会主体育场，其结构特点十分显著，国家体育场结构复杂。
Located at the southern part of the Olympic Green in Beijing, the National Stadium is the main stadium of the 29th Olympiad in 2008. Occupying an area of 21 hectares, it has a floor space of 258,000 square meters. Its seating capacity amounts to 91,000, including 11,000 temporary seats. The venue will host the opening and closing ceremonies of the Beijing Olympic Games and Paralympic Games, the track and field competitions, and the football finals. After the Olympics, the stadium will become a large-scale sports and entertainment facility for the residents of Beijing -- an architectural landmark and Olympic legacy.The main body of the National Stadium has a design life of 100 years. Its fire resistance capability is first-rate, and it can withstand an eight-magnitude earthquake. The water-resistance capability of its underground project is also first-rate.The main body of the National Stadium is a colossal saddle-shaped elliptic steel structure weighing 42,000 tons. It is 333 meters long from north to south, 294 meters wide from east to west, and 69 meters tall.The main body's elements support each other and converge into a grid formation, just like a bird's nest with interlocking branches and twigs. Being a seven-story shear wall system, the stadium's stand has a concrete framework. The upper part of the stand and the stadium's steel structure are separated from each other, but both are based on a joint footing. The roof of the National Stadium is covered by a double-layer membrane structure, with a transparent ETFE membrane fixed on the upper part of the roofing structure and a translucent PTFE membrane fixed on its lower part. A PTFE acoustic ceiling is attached to the side walls of the inner ring.The construction of the National Stadium followed the PPP mode (Private + Public + Partnership ), and it is co-owned by the Beijing State-Owned Assets Management Co. Ltd (BSAM), who shares58 percent of the total assets, and the China International Trust and Investment (CITIC) Consortium, who holds the rest of the assets.Composed of BSAM and CITIC, the National Stadium Co. is responsible for financing, construction, operation and management of the project. CITIC has a post-Games licensed operation right for 30 years.The National Stadium is a complex structure, posing great difficulties for its designers and constructors.DESIGN CONCEPT 设计理念Architectural Summary设计综述国家体育场坐落于奥林匹克公园建筑群的中央位置，地势略微隆起。
ABCD单词
搞笑：drollness,quip,comedy,comic,droll,jape,funniness,hilariousness混乱的：confused,chaotic,muddle,disarranged,disarrayed,disheveled,disorderly,jumbled Messed,rumpled,sloppy,unkempt,untidy不真诚：insincere,disingenuous,affected,artful,assuming,dishonest,dissembling,guileful费力的：demanding,arduous,burdensome,challenging,exacting,grueling,laborious,onerous Persnickety,taxing,toilsome狭隘的: insular,provincial.parochial,sectarian任意的:aimless,arbitrary,desultory,erratic,scattered,stray,haphazard,capricious离题的：discursive,rambling,desultory,digressional,excursive,meandering,wandering顺从的：acquiescent,nonresistant,resigned,tolerant,unresistant,yielding痛恨：abhor,abominate,detest,dislike,hate,loathe轻视蔑视：defy.despise,disregard,flout颂词：eulogy,encomium,accolade,panegyric,tribute掩盖：belie,conceal,curtain,disguise,mask靠谱的：calculable,reliable,responsible,safe,secure,solid,trustable,trustworthy,dependable阻碍：encumber,shackle,stifle,fetter,handcuff,handicap,hinder,impede, manacle, obstruct, Trammel自主决定：discretionary,elective,voluntary检查：scrutinize,examine,review,scan,survey,plumb,overlook,check(out)揭示：disclosure，divulge，exposure理解：appreciate,apprehend,assimilate,behold,catch,cognize,conceive,discern,grasp,perceive Recognize,savvy,see,seize,sense,understand吸引：allure,appeal.attractiveness,captivation,charisma,enchantment,fascination,glamour, Magnetism,seductiveness合理的：valid,analytic,coherent,consequent,rational,reasonable,sensible,sound,well-founded, Well-grounded不重要的：inconsiderable,insignificant,minor,petty,inconsequential,paltry,trifling驱逐：banish,boot out,cast out,chase,dismiss,drum out,expel,extrude,kick out,throw out,turf out, Turn out放弃：abjure,abnegate,forswear,renege,renounce,repeal,repudiate,retract,withdraw包容的：cosmopolitan,universal,transnational,catholic,global,worldwide,ecumenical喜爱：relish,adore,enjoy,like love rejoice,revel,savor无法忍受的：unbearable,insupportable,intolerable,unendurable,unsupportable,unacceptable Harsh,dreadful,wretched,loathsome,repugnant,crushing,overwhelming,comfortless,Painful,appalling,revolting非传统的：dissentient,heterodox,iconoclastic,maverick复杂的：sophisticated,baroque,byzantine,complicated,convoluted,elaborate,intricate,involved Knotty,labyrinthine,tangled爱交际的：gregarious,sociable,social焦虑：anxiety,misgiving,scruple对立：antipodal,antipodean,antithetical,contradictor,contrary,dichotomous,incongruous,polar躲避：avoid,dodge,circumvent,eschew,evade,sidestep,skirt,get around衰弱：decay,decline,deteriorate,emaciate,fade,fail,languish,sag,waste,wilt,wither不重要的：trivial,insubstantial,negligible,nominal,trifling,minimal自主独立的：autonomous,freestanding,independent,separate,sovereign不明智的：impolitic,inadvisable,indelicate,injudicious,tactless,undiplomatic,unwise极好的：exceptional,extraordinary，sterling未准备的：extemporaneous,ad-lib,impromptu,improvisational,improvised,offhand,unconsidered Unplanned,unpremeditated,unprepared,unrehearsed,unstudied全面的：exhaustive,complete,comprehensive,cyclopedic,embracive,thorough匿名的：anonymous，incognito，unidentified，innominate，unnamed，untitled篡改：belie,color,distort,falsify，garble，misinterpret,misrelate,misstate,pervert笨拙的：clumsy,awkward,ham-handed,heavy-handed,maladroit,unhandy,bungling,inept,maladroit 通用的:generic,inclusive,all-embracing,broad,comprehensive,extensive,pervasive,ubiquitous Wholesale,wide,widespread,aggregate,collective,complete,full,plenary,worldwide分等级的：hierarchical，stratified,graded,graduated，ranked预示：forerun,harbinger,herald,adumbrate,augur,forecast,foretell,portend,predict,prognosticate Prophesy,prefigure节制的：abstinent,abstemious,continent,temperate,ascetic,stoic,spartan,self-denying冷漠的：perfunctory,apathetic,casual,disinterested,incurious,indifferent,insouciant,nonchalantUnconcerned不均衡的：lopsided,asymmetric,disproportional,irregular,off-balance,unbalanced,unequal Uneven强有力的：mighty,powerful,robust,stalwart,stout,strong虚弱的：debilitated,effete,enervated,faint,fragile,frail,infirm,languid,sapped,feeble错误：awry,amiss,aside,astray,erroneous,wrong防御性的:defensive,protective病：affection,ail,ailment,bug，complaint，complication,condition,disorder,distemper Distemperature,fever,ill,illness,infirmity,malady,sickness,trouble敌对的：adversarial,antagonistic,adversary,antipathetic,inhospitable,inimical,jaundiced Mortal,negative,unfriendly,unsympathetic增加：augment,extend,aggrandize,amplify,augment,boost,bugle,balloon,burgeon,sprout Snowball,mushroom,wax,pound,enlarge,escalate,expand,extend,multiplyPump up,swell歌唱：song,strain,tune,warble,croon,melody,euphony对立：antipodal,antipodean,antithetical,contradictory,contrary,dichotomous,incongruous,polar 平凡的：common,mundane,ordinary,prosaic宏大：epic,august,grandiose,imposing,magnificent,majestic,monumental,impressive对立：antipode,antithesis,contrary,counter,negative,obverse,reverse空置的：vacant,bare,blank,clean,devoid,stark,empty,vacuous,void使胆怯：daunting,chill,demoralize,dishearten,dismay,dispirit,frustrate,unman,unnerve不同的：assorted,eclectic,heterogeneous,indiscriminate,magpie,mixed,motley,patchwork,piebald Promiscuous,raggle-taggle,ragtag,varied同质的：homogeneous,monochromatic,monotonous,unvaried早于，先于：antecede,antedate,forego,predate,preexist证明为假：belie,confound,confute,debunk,disconfirm,discredit,falsify,rebut,refute,shoot down 获取：acquire,earn,gain,garner,procure,realize,secure,win,achieve完美：unblemished,faultless,flawless,impeccable,indefectible,irreproachable,perfect,seamless筛选：sift,screen,winnow昏昏欲睡的：somnolent,lethargic,slumberous,dozy,drowsy,soporific欺骗的：spurious,specious,beguiling,deceitful,deceiving,deluding,delusive,delusory,fallacious False,misleading陈腐：banality,bromide,chestnut,cliche,homily,platitude,conventionality超然的：ethereal,heavenly,otherworldly,paranormal,preternatural，transcendental,unearthly Unworldly阻碍：cramp,encumber,fetter,handicap,hinder,hobble,impede,stymie,trammel,control重复：redo,reiterate,renew,repeat,duplicate相关：pertain,appertain,bear,concern,refer,relate无依据的：baseless,foundationless,invalid,unfounded,unreasonable,unsubstantiated,unsupported Unwarranted,groundless混合物：agglomerate,collage,hodgepodge,jumble,jungle,medley,montage,salad,variety,welter许可：access,admission,admittance,door,doorway,entry,gateway,ingress,key,passport,ticket和善的：affable,agreeable,easygoing,genial,good-natured,good-tempered,gracious,mellow Pleasant,sweet,well-disposed易怒的：fractious,crabby,cantankerous,choleric,irritable,peevish,pettish,petulant震惊的：jarring,astounding,blindsiding,jolting,startling,stunning少量：meager,niggardly,poor,scant,scarce,skimpy,slender,slim,sparing,stingy大量：abundant,ample.awash,cornucopian,flush,fraught,lousy,replete,swarming,thick,thronging 授权：accredit，certify,charter,commission,empower,enable,invest,license,qualify,vest,warrant 假名:alias,pseudonym,nom de guerre证明：document,demonstrate,establish,substantiate,validate美：pulchritudinous,aesthetic,attractive,beautiful,comely,gorgeous,handsome,knockout,lovely Ravishing,seemly,stunning,taking赞扬：bless,carol,celebrate,emblazon,exalt,extol,glorify,hymn,laud,magnify,resound初始的：incipient,nascent,primitive,primordial移开：remove,strip away。