2012-03MerrillLynchAgConference
物理学家李政道-文档资料
家世
李政道的曾祖父李子义是江苏东吴大学（即现
在的苏州大学）的前身苏州博习书院创建人之 一。李政道的伯祖父曾任东吴大学教务长达数 十年，伯父也在博习医院和东吴大学任职数十 年。 1950年代，台湾时期，李政道在台湾的母亲张 明璋女士和二哥李崇道(李崇道毕业于广西大 学农学院，曾任中兴大学校长、农委会主委)、 二嫂许淑英，因在家里留宿一位旧时广西大学 同学，以“掩护匪谍”罪名入狱。张明璋女士 去世后，李政道将母亲核物理、统计力学、流体 力学、天体物理方面的工作也颇有建树。 1949年与罗森布拉斯和杨振宁合作提出普适费米弱 作用和中间玻色子的存在。 1951年提出水力学中二维空间没有湍流。 1952年与派尼斯合作研究固体物理中极化子的构造。 1954年发表了量子场论中的著名的“李模型”理论。 1957年与奥赫梅和杨振宁合作提出电荷共轭不守恒 和时间不反演的可能性。1959年与杨振宁合作，研 究了硬球玻色气体的分子动理论，对研究氦Ⅱ的超流 动性作出了贡献。
1964-84 哥伦比亚大学费米物理讲座教授 1984- 哥伦比亚大学全级教授 1986- 中国高等科学技术中心（CCAST, WL）主任 1986- 北京现代物理中心主任（北京大学） 1988- 浙江现代物理中心主任（浙江大学） 1997-2003 RIKEN-BNL研究中心主任 2004- RIKEN-BNL研究中心名誉主任 2006至今 北京大学高能物理研究中心主任 1985-93 普林斯顿高等研究院理事会成员 1990－ 以色列特拉维夫大学董事会成员
1946年，20岁的李政道到美国留学，被芝加哥大学 研究生院录取。3年后便以“有特殊见解和成就” 通过了博士论文答辨，被誉为“神童博士”，其时 年仅23岁。 1956年，李政道与杨振宁一起发表了一篇文章，推 翻了物理学中心信息之—宇称守恒，解决了当时的 θ－τ之谜─就是后来称为的K介子有两种不同的衰变 方式：一种衰变成偶宇称态，一种衰变成奇宇称态。 如果弱衰变过程中宇称守恒，那么它们必定是两种 宇称状态不同的K介子。但是从质量和寿命来看， 它们又应该是同一种介子。他们通过分析，认识到 很可能在弱相互作用中宇称不守恒，并提出了几种 检验弱相互作用中宇称是不是守恒的实验途径。次 年，这一理论预见得到吴健雄小组的实验证实。因 此，李政道和杨振宁的工作迅速得到了学术界的公 认，并共同获得了1957年诺贝尔物理学奖。
2012年度国际国内有关学术会议汇总
2012年度国际国内学术会议清单
为了便于我所科研人员提前了解有关学术会议信息，科技处对2012年国际国内相关学术会议进行了汇总，希望感兴趣的人员能积极参加有关会议，多与同行进行学术交流，以提高自身学术水平与交流能力，促进我所学科发展。
（注：2012年国际会议需按照本年度外事批复计划执行，未列入外事计划者，本年度将无法执行。
有意向参加有关国际会议者，请提前准备，本年底将通知大家统一上报明年参会计划。
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科学技术处
2012年2月23日
2012国际相关学术会议清单
2012国内相关学术会议清单。
聚赖氨酸 应用
Biochemical Engineering Journal 65 (2012) 70–81Contents lists available at SciVerse ScienceDirectBiochemical EngineeringJournalj o u r n a l h o m e p a g e :w w w.e l s e v i e r.c o m /l o c a t e /b ejReviewReview on production and medical applications of -polylysineSwet Chand Shukla a ,Amit Singh b ,Anand Kumar Pandey c ,Abha Mishra a ,∗aSchool of Biochemical Engineering,Institute of Technology,Banaras Hindu University,Varanasi 221005,India bDepartment of Pharmacology,Institute of Medical Sciences,Banaras Hindu University,Varanasi 221005,India cSchool of Biomedical Engineering,Institute of Technology,Banaras Hindu University,Varanasi 221005,Indiaa r t i c l ei n f oArticle history:Received 3May 2011Received in revised form 28March 2012Accepted 2April 2012Available online 11 April 2012Keywords:-PolylysineHomopolyamideS.albulus Lysinopolymerus Conjugate Drug carrier Targetinga b s t r a c t-Polylysine (-PL)is a homopolyamide linked by the peptide bond between the carboxylic and epsilon amino group of adjacent lysine molecules.It is naturally occurring biodegradable and nontoxic towards human.This review article gives an insight about the various -PL producing strains,their screening procedures,mechanism of synthesis,characterization,and its application in the medical field.The poly cationic nature of -PL at physiological pH makes it as one of the potential candidates in the field of drug delivery.Most of the biomedical applications till date use synthetic ␣-PLL as a raw material.However,it is believed that naturally occurring -PL would be an ideal substitute.© 2012 Elsevier B.V. All rights reserved.Contents 1.Introduction ..........................................................................................................................................712.Origin and distribution of -PL ......................................................................................................................713.Mechanism of synthesis .............................................................................................................................714.Biosynthesis and molecular genetics ................................................................................................................715.Microbial production of -polylysine ................................................................................................................726.Screening and detection of -PL production in microbial system...................................................................................737.Purification and characterization of -PL ............................................................................................................738.Conformation of -PL ................................................................................................................................749.Application of polylysine in medicine ...............................................................................................................749.1.Polylysine as a drug carrier ...................................................................................................................749.2.Polylysine as nanoparticles...................................................................................................................759.3.Polylysine as a gene carrier...................................................................................................................759.4.Polylysine as liposomes ......................................................................................................................769.5.Polylysine as interferon inducer .............................................................................................................769.6.Polylysine as lipase inhibitor .................................................................................................................779.7.Polylysine as hydrogel ........................................................................................................................779.8.Polylysine as coating material................................................................................................................779.9.Other applications ............................................................................................................................7810.Conclusion ..........................................................................................................................................78References ...........................................................................................................................................78Abbreviations:Pls,polylysine synthetase;NaSCN,sodium thiocynate;FTIR,Fourier transform infrared spectroscopy;NMR,nuclear magnetic resonance spectroscopy;MION,monocrystalline iron oxide nanoparticle;NPs,nanoparticles;IgM,immunoglobulin M.∗Corresponding author.Tel.:+919451887940.E-mail address:abham.bce@itbhu.ac.in (A.Mishra).1369-703X/$–see front matter © 2012 Elsevier B.V. All rights reserved./10.1016/j.bej.2012.04.001S.C.Shukla et al./Biochemical Engineering Journal 65 (2012) 70–81711.Introduction-Polylysine (-PL)is a basic polyamide that consists of 25–30residues of l -lysine with an -amino group-␣-carboxyl group link-age (Fig.1).Polyamide can be grouped into two categories,one in which the polyamide consists of only one type of amino acid linked by amide bonds called homopolyamide and the other which consists of different amino acids in their chain called proteins [1].Furthermore,proteins are biosynthesized under the direction of DNA,while the biosynthesis of homopolyamides is catalyzed by peptide synthetases.Therefore,the antibiotics that are inhibitors of translation such as chloramphenicol,do not affect the biosyn-thesis of polyamides.Proteins in general exhibit exact length,whereas homopolyamides show a remarkable variation in molec-ular weight.Amide linkages in proteins are only formed between ␣-amino and ␣-carboxylic groups (␣-amide linkages),whereas amide bonds in homopolyamide involve other side chain functions such as -and ␥-carboxylic with -amino groups [1].Particularly,chemically synthesized polylysine were found to have linkages between ␣-carboxyl and ␣-amino group.Many workers investi-gated various applications of ␣-PL in the drug delivery system.However,␣-PL was reported to be toxic to human beings,and there-fore,research has now been diverted towards finding naturally occurring polymers [2,3].-PL is an unusual naturally occurring homopolyamide having linkages between the -amino group and ␣-carboxylic group,and it shows high water solubility and sta-bility.No degradation is observed even when the -PL solution is boiled at 100◦C for 30min or autoclaved at 120◦C for 20min [4].-PL was discovered as an extracellular material of Streptomyces albulus ssp.Lysinopolymerus strain 346during screening for Dra-gendorff’s positive substances [5–7].Mutation studies were made by nitrosoguanidine treatment on wild type Lysinopolymerus strain 346to enhance the -PL production.As a result of mutation,S-(2-aminoethyl)-l -cysteine and glycine resistant mutant were isolated,with four times higher amounts of -PL than the wild type [8].-PL is a cationic surface active agent due to its positively charged amino group in water,and hence they were shown to have a wide antimi-crobial activity against yeast,fungi,Gram positive,Gram negative bacterial species [4,9].The excreted polymer is absorbed to the cell surfaces by its cationic property,leading to the striping of outer membrane and by this mechanism the growth of microbes sensi-tive to -PL is inhibited.-PL degrading enzyme plays an important role in self-protection of -PL producing microbes [9].Due to its excellent antimicrobial activity,heat stability and lack of toxicity,it is being used as a food preservative [10,11].Naturally occurring -PL is water soluble,biodegradable,edible and nontoxic toward humans and the environment.Therefore,-PL and its derivatives have been of interest in the recent few years in food,medicine and electronics industries.Derivatives of -PL are also available which offers a wide range of unique applications such as emul-sifying agent,dietary agent,biodegradable fibers,highly water absorbable hydrogels,drug carriers,anticancer agent enhancer,biochip coatings,etc.Polylysine exhibits variety of secondary struc-tures such as random coil,␣-helix,or -sheet conformations in aqueous solution.Moreover,transitions between conformations can be easily achieved using,salt concentration,alcohol con-tent,pH or temperature as an environmental stimulus.There is aH NH*CH 2CH 2CH 2CH 2CH NH 2CO*OHnFig.1.Chemical structure of epsilon polylysine.growing interest in using -PL and its derivatives as biomaterials and extensive research has been done leading to a large number of publications [4,12–15].The present review focuses on various pro-cess parameters for maximal yield of polymer by microbial system more specifically by actinomycetes,probable biosynthetic route and its application,especially in pharmaceutical industries.2.Origin and distribution of -PLNot much is known about the -PL producing microbial species existing in the environment.It is observed that -PL producers mainly belong to two groups of bacteria’s:Streptomycetaceae and Ergot fungi .Besides Streptomyces albulus ,a number of other -PL producing species belonging to Streptomyces,Kitasatospora and an Ergot fungi,Epichole species have been isolated [16].Recently,two Streptomyces species (USE-11and USE-51)have been isolated using two stage culture method [17].3.Mechanism of synthesis-Polylysine (-PL)is a homopolymer characterized by a pep-tide bond between ␣-carboxyl and -amino groups of l -lysine molecules.Biosynthetic study of -PL was carried out in a cell-free system by using a sensitive radioisotopic -PL assay method,suggested that the biosynthesis of -PL is a non ribosomal peptide synthesis and is catalyzed by membrane bound enzymes.In vitro ,-PL synthesis was found to be dependent on ATP and was not affected by ribonuclease,kanamycin or chloramphenicol [18].In a peptide biosynthesis,amino acids are activated either by adeny-lation or phosphorylation of carboxyl group.Adenylation occurs in translation and in the nonribosomal synthesis of a variety of unusual peptides [19,20];Phosphorylation has been suggested for the biosynthesis of glutathione [21].In the former,ATP is con-verted to AMP and pyrophosphate by adenylation,and in the latter,phosphorylation leads to ADP and phosphate as the final prod-ucts.The synthesis of -PL,a homopolypeptide of the basic amino acid l -lysine,is similar to that of poly-(␥-d -glutamate)in terms of adenylation of the substrate amino acid [18].Through the exper-imental observations,the probable mechanism of synthesis was suggested by Kawai et al.showed that in the first step of -PL biosynthesis l -lysine is adenylated at its own carboxyl groups with an ATP-PPi exchange reaction.The active site of a sulfhydryl group of an enzyme forms active aminoacyl thioester intermediates,lead-ing to condensation of activated l -lysine monomer.This is the characteristic feature of nonribosomal peptide synthetase enzyme [22–24].-PL producing strain of Streptomyces albulus was found to pro-duce -PL synthetase (Pls).A gene isolated from the strain was identified as a membrane protein with adenylation and thiolation domains which are characteristic features of the nonribosomal pep-tide synthetases (NRPSs).-PL synthetase has six transmembrane domains surrounding three tandem soluble domains without any thioesterase and condensation domain.This tandem domain itera-tively catalyzes l -lysine polymerization using free l -lysine polymer as an acceptor and Pls-bound l -lysine as a donor,thereby yielding chains of diverse length (Fig.2).Thus,-PL synthetase acts as a ligase for peptide bond formation [25].Yamanaka et al.suggested that -PL synthetase function is regulated by intracellular ATP and found that acidic pH conditions are necessary for the accumulation of intracellular ATP,rather than the inhibition of the -PL degrading enzyme [26].4.Biosynthesis and molecular geneticsThe precursor of -PL biosynthesis was identified to be l -lysine by radiolabeling studies using [14C]-l -lysine in Streptomyces72S.C.Shukla et al./Biochemical Engineering Journal 65 (2012) 70–81Fig.2.Mechanism for synthesis of -polylysine.albulus 346[18].However,a high-molecular-weight plasmid (pNO33;37kbp)was detected in -PL-producing S.albulus ,and the replicon of pNO33was used to construct a cloning vector for S.albu-lus strain [27].The order and number of NRPSs modules determine the chain length of the -PL [24,28].However,the chain length of -PL was shortened by the use of aliphatic hydroxy-compound and -cyclodextrin derivative [29,30].-PL with more than nine l -lysine residues severely inhib-ited the microbial growth while the -PL with less than nine l -lysine residues showed negligible antimicrobial activity.All the strains producing -PL from glycerol showed lower number aver-age molecular weight (M n )than those obtained from glucose [31].The -PL-degrading activity was detected in both -PL tolerant and -PL producing bacteria.The presence of -PL-degrading activity in Streptomyces strains is closely related with -PL-producing activ-ity,which indicates that tolerance against -PL is probably required for -PL producers.The presence of -PL degrading enzyme is detri-mental to industrial production of -PL.Therefore,-PL degrading enzyme of S.albulus was purified,characterized and the gene encoding an -PL degrading enzyme of S.albulus was cloned,and analyzed [32].The -PL-degrading enzyme of S.albulus is tightly bound to the cell membrane.The enzyme was solubilized by NaSCN in the presence of Zn 2+and was purified to homogeneity by phenyl-Sepharose CL-4B column chromatography,with a molecular mass of 54kDa.The enzymatic mode of degradation was exotype mode and released N-terminal l -lysine’s one by one.Streptomyces vir-giniae NBRC 12827and Streptomyces noursei NBRC 15452showed high -PL-degrading aminopeptidase activity and both strains have the ability to produce -PL,indicating a strong correlation between the existence of -PL degrading enzyme and -PL produc-ing activity [33].-PL degrading enzymes were also found in -PL tolerant microorganisms,Sphingobacterium multivorum OJ10and Chryseobacterium sp.OJ7,which were isolated through enrichmentof the culture media with various concentrations of -PL.S.mul-tivorum OJ10could grow well,even in the presence of 10mg/ml -PL,without a prolonged lag phase.The -PL-degrading enzyme activity was also detected in the cell-free extract of -PL tolerant S.multivorum OJ10.The enzyme catalyzed an exotype degradation of -PL and was Co 2+or Ca 2+ion activated aminopeptidase.This indicates the contribution of -PL-degrading enzymes to the toler-ance against -PL [34].An -PL degrading enzyme of -PL tolerant Chryseobacterium sp.OJ7,was also characterized and the purified enzyme catalyzed the endotype degradation of -PL,in contrast to those of Streptomyces albulus and Sphingobacterium multivorum OJ10.Probably,their possession of proteases enables their growth in the presence of a high -PL concentration.-PL degradation was also observed by commercially available proteases,such as Pro-tease A,Protease P and Peptidase R [34,35].5.Microbial production of -polylysinePolylysine can be synthesized by chemical polymerization start-ing from l -lysine or its derivatives.Researchers described two different routes to polymerize lysine residues without the use of protection groups.However,linear -PLL can be obtained by applying 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide as an activating agent for the polycondensation of l -lysine in an aqueous medium.In contrast to this,␣-poly(l -lysine)can be obtained by using dicyclohexyl carbodiimide and 18-crown-6ether in chloro-form [36].Dendrimeric ␣,-polylysine were synthesized by using solid phase peptide synthesis method and used dendritic ␣,-polylysine as a delivery agent for oligonucleotides [37,38].Moccia et al.for the first time reported ␣,-polylysine by assembling Fmoc and Boc protected l -lysine monomers by solid phase synthesis [39].Guo et al.synthesized -PL-analogous polypeptides with not only similar ␣-amino side groups but also similar main chain throughS.C.Shukla et al./Biochemical Engineering Journal65 (2012) 70–8173microwave assisted click polymerization technique[40].Recently, Roviello et al.synthesized a cationic peptide based on l-lysine and l-diaminobutyric acid for thefirst time by solid phase synthesis [41].-PL was discovered as an extracellular material produced by filamentous actinomycetes group of micro-organism Streptomyces albulus ssp.Lysinopolymerus strain346more than35years ago [5].It is synthesized by a nonribosomal peptide synthetase and released extracellularly.In actinomycetes group of organisms l-lysine is synthesized through the diaminopimelic acid pathway. Diaminopimelate is formed via l-aspartate(Asp)produced by com-bining oxaloacetate in the tricarboxylic acid cycle with ammonium as a nitrogen source.Citrate was found to be facilitator for the production much more than other organic acids of TCA cycle[24].Studies revealed that decline in pH during the fermentation pro-cess is an essential condition for the accumulation of-PL.Shima et al.carried out two-step cultivation method for S.albulus.Strain wasfirst grown for24h in a culture medium containing glycerol as carbon source with yeast extract,then in second step medium was replaced by glucose,citric acid with(NH4)2SO4[42].It was found that the mutant of strain346decreases the culture pH from its initial value of6.8–4.2by36h,and slowly decreased thereafter to 3.2at96h.The accumulation of-PL in the broth increased signifi-cantly when the culture pH was about4.0.The fed batch cultivation was adopted to enhance the-PL production with two distinct phases.In phase I,cell was grown at pH(6.8)optimum for cul-ture growth then in phase II,the pH was kept around4.0by the addition of glucose.Depletion of glucose causes an increase in pH of the culture broth leading to the degradation of the produced -PL.Thus the pH control strategy in fed batch culture success-fully enhanced the yield of-PL to almost9fold[43].The airlift bioreactor(ABR)was also evaluated and compared with jar fer-mentor for-PL production.The results showed that the production level of-PL in a ABR with a power consumption of0.3kW/m3was similar to that in a5-l jar fermentor with power consumption of 8.0kW/m3.The leakage of intracellular nucleic acid(INA)-related substance into the culture broth in the ABR was70%less than that in the jar fermentor.Thus,ABR system with low intracel-lular nucleic acid-related substances minimize the difficulties of downstream processing for recovery and purification of the poly-mer products.Furthermore,the use of ABR is promising tool for the low-cost production of-PL of high purity[44].In some-PL producing strains,the production of-PL is unstable and depen-dent on cell density which can cause problem such as high viscosity and low oxygen transfer efficiency.Furthermore,increase of agita-tion speeds leads to the rise of shear stresses which might cause undesired effects on mycelial morphology,product formation,and product yields.Bioprocesses using immobilized cells on various inert supports can increase overall productivity and minimize pro-duction costs[45].Bankar et al.reported that aeration and agitation of the fermentation broth markedly affect-PL production,cell mass formation,and glycerol utilization.Fermentation kinetics per-formed revealed that-PL production is growth-associated,and agitation speed of300rpm and aeration rate at2.0vvm supports higher yields of-PL[46].Many efforts have been made to opti-mize the media in order to enhance the productivity of-PL.Shih and Shen applied response surface methodology for optimization of-PL production by Streptomyces albulus IFO14147[47].It was found that-PL production started on agar plated with iron two or three days earlier than that on plates without iron.Manganese and cobalt were also found to have stimulating effect on-PL produc-tion.Kitasatospora kifunense strain produces-PL of shorter chain length about8–17lysine residues[48].Metabolic precursors such as amino acids,tricarboxylic acid cycle intermediates and cofactors have been investigated for improved production of-PL.Addition of citric acid after24h and l-aspartate after36h of fermentation medium had a significant effect on-PL production[49].Zhang et al.investigated the production of-PL on immobilized cells of Kitasatospora sp.MY5-36on bagasse,macroporous silica gel,syn-thetic sponge,loofah sponge and found that loofah sponge gave highest production of-PL in shakeflask culture[50].6.Screening and detection of-PL production in microbial systemNishikawa and Ogawa developed a simple screening method to detect-PL producing microbes.Screenings were carried out on agar plates containing either basic or acidic dyes.The dyes used were,Poly R-478,Remazol Brilliant Blue-R(RBBR)and Methylene blue.The screening method was based on the rationale interac-tion that occurs between charged groups of the secreted-PL and charged group of the basic or acidic dyes.A synthetic glycerol(SG) medium containing either0.02%of acidic dye Poly R-478/RBBR or0.002%of Methylene blue was used for the primary screen-ing.The SG medium was composed of glycerol10g,ammonium sulfate0.66g,sodium dihydrogen phosphate0.68g,magnesium phosphate heptahydrate0.25g,yeast extract0.1g,and1.0ml of Kirk’s mineral solution in1l of distilled water.The pH was adjusted to7.0with1M NaOH solution,and the medium was solidified by adding1.5%agar.The plates were incubated at28◦C for about one week;microbes forming specific colonies interacting with dyes were picked up and purified after several culture transfers.The acidic dye condensed around the organism’s colonies while basic dye was excluded from the surrounding zone.A zone of at least five mm in diameter for each colony was needed to visualize the interaction between secreted substances and dyes[16].The concentrations of-PL in the culture broth can be deter-mined by using either the spectrophotometric method or HPLC method.The colorimetric method is based on the interaction between-PL and methyl orange,which is an anionic dye,and thus the interaction of cationic-PL with anionic methyl orange in the reaction mixture led to form a water insoluble complex[51].The HPLC method for-PL detection was reported by Kahar et al.in which HPLC column(Tsk gel ODS-120T,4.6mm×250mm)with a mobile phase comprising of0.1%H3PO4was used[43].7.Purification and characterization of-PL-PL a cationic polymer,can be isolated at neutral pH,and puri-fied from the culture broth by ion exchange chromatography using an Amberlite IRC-50(H+form)column[5,52].The culture super-natant can be passed through an Amberlite IRC-50column at pH 8.5with successive washing by0.2N acetic acid and water.The elution can be made with0.1N hydrochloric acid,and the eluate can be neutralized with0.1N sodium hydroxide to pH6.5.Sub-sequent purification can be done by using CM-cellulose column chromatography to get-PL in homogeneity.The purification of the product can be monitored by UV absorption at220nm and fur-ther characterized by amino acid analysis.The molecular weight of-PL can be estimated by gelfiltration on a Sephadex column [16,53].Kobayashi et al.extracted the-PL from Kitasatospora kifu-nense.The pH of the culturefiltrate wasfirst adjusted to7.0,and the aliquot was mixed with Gly-His-Lys acetate salt as an inter-nal peptide standard.The resulting mixture was then applied to Sep-Pak Light CM cartridge.The cartridge was washed with water and-PL was eluted with0.1M HCl.The eluate was lyophilized and the residue was dissolved in0.1%pentafluoropropionic acid [46].Recently,ultra-filtration technique for fractionation of-PL of different molecular weight has been applied.The-PL with molec-ular weight higher than2kDa form a-turn conformation whereas molecular weight smaller than2kDa possesses a random coil74S.C.Shukla et al./Biochemical Engineering Journal65 (2012) 70–81conformation.The fraction of-PL with molecular weight higher than2kDa was found to have significant antibacterial activity, while the fraction with molecular weight smaller than2kDa shows nominal antibacterial activity[54].8.Conformation of-PLStructure and conformation studies are prerequisite to under-stand the functional behavior of-PL.Numerous workers have investigated the conformation and the molecular structure of microbially produced-PL by NMR,IR and CD spectroscopy[55,56]. The thermal property of crystalline-PL was determined by Lee et al.[52].The glass transition temperature(T g)and the melting point(T m)was observed to be88◦C and172.8◦C respectively.The results from pH dependent IR and CD spectra,1H and13C NMR chemical shifts together with that of13C spin-lattice relaxation times T1indicated that-PL assumes a-sheet conformation in aqueous alkaline solution.-PL at acidic pH might be in an electro-statically expanded conformation due to repulsion of protonated ␣-amino group,whereas at elevated pH(above p K a of the␣-amino group)the conformation was found to be similar to the antiparallel -sheet.The molecular structure and conformation of microbial-PL was studied by FT-IR and Raman spectroscopy.-PL was found to assumed a-sheet conformation in the solid state and solid state 13C NMR also revealed that-PL existed as a mixture of two crys-talline forms.Spin-lattice relaxation times yield two kinds of T1s corresponding to the crystalline and amorphous components,with the degree of crystallinity as63%[57].Solid-state high-resolution13C and15N NMR spectra of micro-bial-PL derivatives with azo dyes have been measured.These chemically modified-PL’s Exhibit15N NMR signals characteristic of the binding mode at the␣-amino groups.The spectral analy-sis reveals that the-PL/DC sample contains a small amount of ion complexes with methyl orange(MO).It has been shown that side chain␣-amino group of-PL does not make a covalent bond with methyl orange(MO)but forms a poly-ion complex,(-PL)-NH3+SO3−-(MO).On the other hand,dabsyl chloride(DC)makes covalent bond with-PL to form sulfonamide,(-PL)-NH-SO2-(DC). However,a few tens percent of DC change to MO by hydrolysis to form a poly-ion complex,(-PL)-NH3+SO3−-(MO)[58].Rosenberg and Shoham characterized the secondary structure of polylysine with a new parameter namely,the intensity ratio of the bands of charged side chain amine NH3+and amide NH bands.The enthalpy of the secondary structure transition,which is observed in PLL at the change of pH from11to1amounts to4.7kJ mol−1[59].9.Application of polylysine in medicinePolylysine is available in a large variety of molecular weights. As a polypeptide,polylysine can be degraded by cells effortlessly. Therefore,it has been used as a delivery vehicle for small drugs[60]. The epsilon amino group of lysine is positively charged at phys-iological pH.Thus,the polycationic polylysine ionically interacts with polyanion,such as DNA.This interaction of polylysine with DNA has been compacted it in a different structure that has been characterized in detail by several workers[61–66].In addition,the epsilon amino group is a good nucleophile above pH8.0and there-fore,easily reacts with a variety of reagents to form a stable bond and covalently attached ligands to the molecule.Several coupling methods have been reported for preparation of conjugated of-PL [67–70].(a)Modification of epsilon amino groups of polylysine with bifunctional linkers containing a reactive esters,usually add a reac-tive thiol group to the polylysine molecule and consequent reaction with a thiol leads to a disulfide or thioether bond,respectively.This has been used to couple large molecules,such as proteins to polylysine.(b)Compounds containing a carboxyl group can be acti-vated by carbodiimide,leading to the formation of an amide bond with an epsilon amino group of polylysine.(c)Aldehydes,such as reducing sugars or oxidized glycoprotein,form hydrolysable schiff bases with amino groups of-PL,which can be selectively reduced with sodium cyanoborohydride to form a stable secondary amine.(d)Isothiocyanate reacts with epsilon amino groups by forming a thiourea derivative.(e)Antibody coupling can also be done specif-ically to the N-terminal amino group of polylysine[71,72].A variety of molecules such as proteins,sugar molecules and other small molecules have been coupled to polylysine by using these methods.Purification of the conjugates are usually being achieved by dialysis or gelfiltration in conjunction with ion-exchange chromatography or preparative gel electrophoresis. Fractionation of the ligand–polylysine ratio and conjugate size can be done by using acid urea gel electrophoresis in combination with cation-exchange HPLC,ninhydrin assay and ligand analysis (sugar,transferrin,etc.)[73].Galactose terminated saccharides such as galactose,lactose and N-acetylgalactosamine were found to be accumulated exclusively in the liver,probably by their hepatic receptor.These conjugates could therefore be excellent carriers for a drug delivery system to the liver.The other saccharides such as the mannosyl and fucosyl conjugates are preferentially delivered to the reticuloendothelial systems such as those in the liver,spleen and bone marrow.In particular,fucosyl conjugates accumulated more in the bone marrow than in the spleen whereas xylosyl con-jugates accumulated mostly in the liver and lung.Generally,the accumulated amount in the target tissue increased with increasing molecular weight and an increased number of saccharide units on each monomer residues of polymer[74].One of the disadvantages of polylysine from the pharmaceu-tical point of view is its heterogeneity with respect to molecular size.The size distribution of polylysine with degrees of polymer-ization(dp)can be reduced by gel permeation chromatography. Al-Jamal et al.studied sixth generation(G6)dendrimer molecules of␣-poly-l-lysine(␣-PLL)to exhibit systemic antiangiogenic activ-ity that could lead to solid tumor growth arrest.Their work showed that G6PLL dendrimer have an ability to accumulate and persist in solid tumor sites after systemic administration and exhibit antian-giogenic activity[75].Sugao et al.reported6th generation dendritic ␣-PLL as a carrier for NFB decoy oligonucleotide to treat hepatitis [76].Han et al.synthesized a new anti-HIV dendrimer which con-sisted of sulfated oligosaccharide cluster consisting with polylysine core scaffold.The anti-HIV activity of polylysine-dendritic sulfated cellobiose was found to have EC50-3.2g/ml for viral replication which is as high as that of the currently clinically used AIDs drugs. The results also indicated that biological activities were improved because of dendritic structure in comparison to oligosaccharide cluster which were reported to have low anti-HIV activity[77].9.1.Polylysine as a drug carrierPolylysine can be used as a carrier in the membrane transport of proteins and drugs.Shen and Ryser reported that␣-PLL was found to be easily taken up by cultured cells.In fact,the conju-gation of drug to polylysine markedly increased its cellular uptake and offers a new way to overcome drug resistance related to defi-cient transport[60,78,79].Resistance toward methotrexate has been encountered in the treatment of cancer patients.The poly lysine conjugates of methotrexate(MTX)were taken up by cells at a higher rate than free drugs form.This increased uptake can overcome drug resistance due to deficient MTX transport.Addi-tion of heparin at a high concentration restores growth inhibitory effect of MTX-poly lysine[11,60].Shen and Ryser worked conjuga-tion of␣-PLL to human serum albumin and horseradish-peroxidase。
2012年奥巴马胜选演讲全文(中英文对照版)
2012 年奥巴马胜选演讲全文Thank you so much.非常感谢你们。
Tonight, more than 200 years after a former colony won the right to determine its own destiny, the task of perfecting our union moves forward.今夜，的任务又向前推进了一步。
It moves forward because of you. It moves forward because you reaffirmed the spirit that has triumphed over war and depression, the spirit that has lifted this country from the depths of despair to the great heights of hope, the belief that while each of us will pursue our own individual dreams, we are an American family and we rise or fall together as one nation and as one people.这一进程是因为你们而向前推进的，的精神，都在追求自己的个人梦想、信仰。
Tonight, in this election, you, the American people, reminded us that while our road has been hard, while our journey has been long, we have picked ourselves up, we have fought our way back, and we know in our hearts that for the United States of America the best is yet to come.今夜，在此次选举中，你们这些美国人民提醒我们，虽然我们的道路一直艰难，虽然我们的旅程一直漫长，对美利坚合众国来说，最美好一切属于未来。
2012美国总统大选辩论第三场-中文
2012美国大选第三场辩论国总统大选第三场、也是最后一场辩论22日在美国佛罗里达州博卡拉顿的林恩大学举行。
本场辩论以美国外交政策为主题。
由于总统奥巴马与共和党总统候选人罗姆尼在前两场辩论中战成平手，且目前选情胶着，第三场辩论的重要性大增，受关注程度更高。
现场，两人可谓开足火力，激烈碰撞。
主持人：大家晚上好，我们在佛罗里达州博卡拉顿的林恩大学，这次问题并没有和我们总统的候选人进行沟通，所以我们现在这次辩论当中观众不要喝彩或者是喝倒彩，欢迎奥巴马总统和罗姆尼州长。
罗姆尼：我们必须要确保我们能够把这些恐怖分子都绳之以法，这是最重要的，更重要的是我们必须要找到方法，让穆斯林国家能够反对激进主义，我们正确做法是让反美的，比如穆斯林的激进分子集团，让他们改变他们的做法，我们怎么样能够帮助世界来反对恐怖主义，我们现在应该让我们的外资援助，用这些方法能够来应对这些问题。
第二点就是教育。
第三点就是我们必须要有平等。
第四点就是法制。
我们必须要有一个法制的社会，那么在过去的几年当中，我们看到的是中东地区的动乱，我们看到了中东地区非常严重的动乱，还有基地组织，都扰乱了中东地区的和平，我们在这里看到中东地区是有一些进展，但是还是有很多的悲剧发生，我们看到埃及有8000万人口，我们希望能够确保在埃及还有中东地区能够有一些进展。
叙利亚问题，我们现在叙利亚总统阿萨德仍然在台上镇压民众，伊朗也是很重要的问题。
他也影响到了地区的安全和和平。
奥巴马：罗姆尼州长我非常高兴，你认为基地组织是一个威胁，你回答这个问题的时候是俄国并不是基地组织。
当我们说到外交政策的时候，你其实用的是90年代的外交政策，你当时说的是，你并不是很在乎在伊拉克发生的事情，但是在几个星期之前，你说我们应该现在在伊拉克增兵，现在我们所面临的一个挑战，当然我知道你现在也没有这个条件来实施外交政策，但是我想说的是你的外交政策上的观点是错误的。
比如说我们在大规模杀伤性武器问题上，你说我们现在应该在伊拉克增兵，你说我们应该通过和俄国的条约，你的答案并不是肯定的，你说可能要从阿富汗撤兵，这个要看清楚。
内部参考资料.doc
内部参考资料外事与港澳台工作通讯2003年12月同济大学外事办公室与港澳台事务办公室主编本期导读校际交往 (2)万钢副校长会见英国女王大学副校长一行王伯伟校长助理会见日本九州大学访问团一行周祖翼副书记会见美国丹佛大学工程与计算机学院院长国际会议 (2)木结构技术研讨会在我校举行第二届二氧化氯(C102)与水处理技术国际研讨会在我校举行2000年汉诺威世博会学术交流与合作会在锦江小礼堂举行智能结构及结构诊断与控制交流会在我校举行授予荣誉称号 (3)授予张伟韬博士我校兼职教授称号授予Wagner先生我校顾问教授称号新签协议 (4)与爱尔兰三一大学签署谅解备忘录与美国加州大学伯克莱分校高科技管理项目（MOT）签订联合授课合作协议校领导出访 (4)虞丽娟副书记访问美国周家伦书记访问爱尔兰、英国和德国陈成澍副校长访问日本综合信息 (5)德国Carl Hanser出版社代表团来访万钢副校长参加德国博世股份公司副总裁Bohr博士举办的晚宴黄自萍校长助理会见法国阿尔卑斯大区伊泽省政府主席代表团一行王伯伟校长助理会见日本水道技术中心理事长滕原正弘一行外办举行圣诞·新年招待会港澳台动态 (7)万钢副校长出席“光华奖学金”颁奖典礼香港理工大学“就业探索考察交流团”来我校访问交流校际交往法国Valenciennes大学国际交流部负责人来访12月1日，法国Valenciennes大学国际交流部负责人Ingrid女士来访我校，外办副主任李梅博士接待了来宾。
法国Valenciennes大学是法国北部的新兴大学，是法国尝试学制改革的四所试点学校之一。
该校此次来访旨在我校机械、机电等与汽车相关领域招收一批学生赴法攻读硕士学位。
之后，来访者还访问了我校汽车学院，商谈合作。
万钢副校长会见英国女王大学副校长一行12月2日上午，女王大学Kennith Bell副校长、外办Robin Harley主任和中国事务负责人王黎明博士一行就两校合作事宜拜访我校。
CGCLSTCS发布的国际顶级学术会议一览表 (2012年度版)
CGCL/STCS发布的国际顶级学术会议一览表 (2012年度版) Rank A-11.National Conference on Artificial Intelligence (AAAI)2.International Conference on Architectural Support for Programming Languages and Operating Systems (ASPLOS)3.ACM Conference on Computer and Communication Security (CCS)4.ACM Conference on Human Factors in Computing Systems (CHI)5.Annual International Cryptology Conference (CRYPTO)6.IEEE Conference on Computer Vision and Pattern Recognition (CVPR)ENIX Conference on File and Storage Techniques (FAST)8.IEEE Symposium on Foundations of Computer Science (FOCS)9.ACM Symposium on the Foundations of Software Engineering (FSE)10.International Symposium on High Performance Computer Architecture (HPCA)11.International Conference on Data Engineering (ICDE)12.IEEE International Conference on Computer Vision (ICCV)13.International Conference on Machine Learning (ICML)14.IEEE International Conference on Network Protocols (ICNP)15.International Conference on Software Engineering (ICSE)16.International Joint Conference on Artificial Intelligence (IJCAI)17.IEEE Conference on Computer Communications (INFOCOM)18.International Symposium on Computer Architecture (ISCA)19.ACM SIGKDD International Conference on Knowledge Discovery and Data Mining (KDD)20.Annual IEEE/ACM International Symposium on Microarchitecture (MICRO)21.ACM International Conference on Multimedia (MM)22.International Conference on Mobile Computing and Networking (MobiCom)ENIX Symposium on Networked Systems Design and Implementation (NSDI)24.International Conference on Object Oriented Programming, Systems, Languages and Applications (OOPSLA)ENIX Conference on Operating System and Design (OSDI)26.ACM Conference on Programming Language Design and Implementation (PLDI)27.Annual ACM Symposium on Principles of Distributed Computing (PODC)28.ACM Symposium on Principles of Programming Languages (POPL)29.IEEE Real-Time Systems Symposium (RTSS)30.ACM SIGCOMM Conference (SIGCOMM)31.ACM Conference on Computer Graphics and Interactive Techniques (SIGGRAPH)32.ACM Annual International ACM SIGIR Conference on Research and Development in Information Retrieval_r(SIGIR)33.International Conference on Management of Data and Symposium on Principles of Database Systems (SIGMOD/PODS)34.ACM Symposium on Operating Systems Principles (SOSP)35.IEEE Symposium on Security and Privacy (SP)36.Annual ACM Symposium on Theory of Computing (STOC)ENIX Annual Technical Conference (USENIX)38.International Conference on Very Large Data Bases (VLDB)39.IEEE Visualization Conference (Vis)40.International World Wide Web Conference (WWW)Rank A-21. International Conference on Dependable Systems and Networks (DSN)2. International Symposium on High Performance Distributed Computing (HPDC)3. International Conference on Distributed Computing Systems (ICDCS)4. ACM International Conference on Supercomputing (ICS)5. ACM/IFIP/USENIX International Middleware Conference (Middleware)6. ACM SIGPLAN Symposium on Principles and Practice of Parallel Programming (PPoPP)7. Supercomputing (SC’XY) Conference8. ACM Conference on Measurement and Modeling of Computer Systems (SIGMETRICS)9. Annual ACM Symposium on Parallel Algorithms and Architectures (SPAA)10. ACM International Conference on Virtual Execution Environments (VEE)Rank B1. Annual Computer Security Applications Conference (ACSAC)2. International Symposium on Code Generation and Optimization (CGO)3. ACM International Conference on emerging Networking EXperiments and Technologies (CoNEXT)4. ACM Conference on Computer Supported Cooperative Work (CSCW)5. Annual Eurocrypt Conference (Eurocrypt)6. European Conference on Computer Systems (EuroSys)7. Workshop on Hot Topics in Networking (HotNets)8. Workshop on Hot Topics in Operating Systems (HotOS)9. IEEE International Conference on Data Mining (ICDM)10. USENIX Internet Measurement Conference (IMC)11. IEEE International Parallel and Distributed Processing Symposium (IPDPS)12. International Semantic Web Conference (ISWC)13. IEEE/ACM International Workshop on Quality of Service（****IWQoS*****）14. USENIX Large Installation System Administration Conference (LISA)15. International Symposium on Modeling, Analysis, and Simulation of Computer & Telecommunication Systems (MASCOTS)16. ACM Multimedia Systems Conference (MMSys)17. ACM International Symposium on Mobile Ad Hoc Networking and Computing (MobiHoc)18. ACM International Conference on Mobile Systems, Applications, and Services (MobiSys)19. IEEE Symposium on Mass Storage Systems/NASA Goddard Conference on Mass Storage Systems and Technologies (MSS/MSST)20. Annual Network & Distributed System Security Symposium (NDSS)21. International Conference on Parallel Architectures and Compilation Techniques (PACT)22. IEEE International Conference on Pervasive Computing and Communications (PerCom)23. IFIP International Symposium on Computer Performance Modeling, Measurement and Evaluation (Performance)24. SIAM Conference on Parallel Processing for Scientific Computing (PP)25. IEEE Real-Time and Embedded Technology and Applications Symposium (RTAS)26. USENIX Security Symposium (Security)27. ACM Conference on Embedded Networked Sensor Systems (SenSys)28. ACM Symposium on Cloud Computing (SOCC)29. ACM-SIAM Symposium on Discrete Algorithms (SODA)30. International Symposium on Reliable Distributed Systems (SRDS)。
四色定理及其计算机证明
四⾊定理及其计算机证明为了⿊这个：“OpenAI发⽂表⽰，他们已经为Lean创建了⼀个神经定理证明器，⽤于解决各种具有挑战性的⾼中奥林匹克问题，包括两个改编⾃IMO的问题和来⾃AMC12、AIME竞赛的若⼲问题。
该证明器使⽤⼀个语⾔模型来寻找形式化命题(formal statement)的证明。
”The four color theorem was proved in 1976 by Kenneth Appel and Wolfgang Haken after many false proofs and counterexamples (unlike the five color theorem, proved in the 1800s, which states that five colors are enough to color a map)...The Appel and Haken proof attracted a fair amount of criticism. Part of it concerned the proof style: the statement of the Four Colour Theorem is simple and elegant so many mathematicians expected a simple and elegant proof that would explain, at least informally, why the theorem was true - not opaque IBM 370 assembly language programs.System/370 Model 148The new model also offers increased system throughput -- the amount of time it takes to perform a given amount of work -- compared to the Models 135 and 145. The Model 148 is available with 1,048,576 or 2,097,152 characters of memory. ⾼达1MB或2MB内存。
Implementing the Jacobi Algorithm for Solving Eigenvalues of Symmetric Matrices with CUDA
2012 IEEE Seventh International Conference on Networking, Architecture, and StorageImplementing the Jacobi Algorithm for Solving Eigenvalues of Symmetric Matrices with CUDATao Wang1 , Longjiang Guo1,2† , Guilin Li3 , Jinbao Li1,2 , Renda Wang1 , Meirui Ren1,2 , Jing (Selena) He4 1 School of Computer Science and Technology, Heilongjiang University, Harbin, 150080, China 2 Key Laboratory of Database and Parallel Computing of Heilongjiang Province, Harbin 150080, China 3 Software School of Xiamen University, Xiamen, Fujian 361005, China 4 Department of Computer Science, Kennesaw State University, Kennesaw, GA, 30144, USA Email: longjiangguo@Abstract—Solving the eigenvalues of matrices is an open problem which is often related to scientific computation. With the increasing of the order of matrices, traditional sequential algorithms are unable to meet the needs for the calculation time. Although people can use cluster systems in a short time to solve the eigenvalues of large-scale matrices, it will bring an increase in equipment costs and power consumption. This paper proposes a parallel algorithm named Jacobi on gpu which is implemented by CUDA (Computer Unified Device Architecture) on GPU (Graphic Process Unit) to solve the eigenvalues of symmetric matrices. In our experimental environment, we have Intel Core i5-760 quad-core CPU, NVIDIA GeForce GTX460 card, and Win7 64-bit operating system. When the size of matrix is 10240×10240, the number of iterations is 10000 times, the speedup ratio is 13.71. As the size of matrices increase, the speedup ratio increases correspondingly. Moreover, as the number of iterations increases, the speedup ratio is very stable. When the size of matrix is 8192×8192, the number of iterations are 1000, 2000, 4000, 8000 and 16000 respectively, the standard deviation of the speedup ratio is 0.1161. The experimental results show that the Jacobi on gpu algorithm can save more running time than traditional sequential algorithms and the speedup ratio is 3.02∼13.71. Therefore, the computing time of traditional sequential algorithms to solve the eigenvalues of matrices is reduced significantly. Keywords-Matrix eigenvalue; CUDA; Jacobi iteration; GPU; Symmetric Matrix;I. I NTRODUCTION Solving the eigenvalues of matrices is one of the most common and important operation in linear algebra. It has wide applications in scientific computing [1]. Solving the eigenvalues of matrices not only can directly help to solve the nonlinear programming, optimization, ordinary differential equations, and a variety of math problems, but also plays an important role in structural mechanics, engineering design, computational physics, and quantum mechanics. Nowadays, because of its important and wide applications, the matrix eigenvalue problem becomes one of the main computational tasks of high-performance computers. However, with the development of advanced technologies, and1 †To whom correspondences should be addressed. Email: longjiangguo@the improvement of computing power, the size of matrices which people deal with has been increased dramatically. For example, in the field of computational fluid dynamics, statistical, structural engineering, quantum physics, chemical engineering, economic models, the aerospace industry, hydropower, weather forecasting, integrated circuit simulation, signal processing and control, network queuing simulation of Markov chains, and many other fields , it is needed to solve the eigenvalues with large-scale matrices. For some practical problems, the orders of matrices often reach thousands, tens of thousands, or even millions [2]. However, the majority of methods for solving the eigenvalues of matrices adopts the sequential algorithm, or parallel methods on cluster systems. The speed of sequential solutions is undoubtedly very slow for large matrices. The speed of cluster systems is much faster than the sequential methods in solving the eigenvalues of matrices. Nevertheless, using cluster systems brings an increase in equipment costs and power consumptions. Thus, people need to pay more expensive computational costs. For example, a cluster system consists of eight computers. The total cost includes the costs of the eight stand-alone machines, the costs of the connections among these eight machines, and the high maintenance costs. Additionally, the power consumption is eight times or more than using only one machine. The costs of using cluster systems usually range from tens of thousands to hundreds of thousands of dollars (e.g., the Huaan-RAC cluster costs 185,000 RMB in 2011), and their power consumptions are very large. This expensive cost for accelerating computing ability is not affordable for some people. In recent years, GPU is already famous for the programming capabilities for the large-scale fast calculations. The CUDA technology proposed by NVIDIA is an outstanding representative of this area [3]. CUDA programming gives people a new idea, and also provides us a new way to solve the eigenvalues of matrices. In recent years, the development of CUDA has become a focus on academic researches. People not only use CUDA to deal with graphics and images, but also use it to handle numerical calculations.69978-0-7695-4722-0/12 $26.00 © 2012 IEEE DOI 10.1109/NAS.2012.12For example, R. R. Amossen et al. presented a novel data layout, BATMAP, which is particularly well suitable for parallel processing. Moreover BATMAP is compact even for sparse data [4]. Grand et al. proposed a broad-phase collision detection with CUDA [5]. A. A. Aqrawi et al. presented a method using compression for large seismic data sets on modern GPUs and CPUs [6]. Later, A. A. Aqrawi et al. presented the 3D convolution for large data sets on modern GPUs [7]. J. Barnat et al. designed a new CUDAaware procedure for pivot selection and implemented parallel algorithms using CUDA accelerated computation [8]. A. Hagiescu et al. described an automated compilation flow that maps most stream processing applications onto GPUs by taking two important architectural features of NVIDIA GPUs into consideration , namely, interleaved execution, as well as the small amount of shared memory available in each streaming multiprocessor [9]. This paper proposes a parallel algorithm named Jacobi on gpu which is implemented by CUDA on GPU to solve the eigenvalues of symmetric matrices. In our experimental environment, we have Intel Core i5-760 quadcore CPU, NVIDIA GeForce GTX460 card, and Win7 64-bit operating system. When the size of matrix is 10240×10240, the number of iterations is 10000 times, the speedup ratio is 13.71. As the size of matrices increases, the speedup ratio increases. As the number of iterations increases, the speedup ratio is very stable. When the size of matrix is 8192×8192, the number of iterations are 1000, 2000, 4000, 8000 and 16000 respectively, the standard deviation of the speedup ratio is 0.1161. The experimental results show that the Jacobi on gpu algorithm can save more running time than traditional sequential algorithms. Moveover the speedup ratio is increased from 3.02 to 13.71. Therefore, the computation time is reduced significantly compared with traditional sequential algorithms. The contributions of this paper are summarized as follows:∙II. R ELATE W ORK There are many algorithms proposed to solve the eigenvalues of matrices, such as, Jacobi iteration method, QR method, and Power method [10]. However, the majority of these algorithms are implemented sequentially. The speed of sequential solutions undoubtedly is very slow for large matrices. B. Butrylo et al. presented a parallel algorithm called SSOR which preconditioning implemented on dynamic SMP clusters with communication on the fly [11]. In this paper, they use SMP cluster system to improve the efficiency of solving the matrices eigenvalues. T. Auckenthaler et al. presented a parallel solution of partial symmetric eigenvalue problems, by using the parallel computer system to solve the eigenvalues of matrices [12]. Cluster systems can be used to solve the eigenvalues of large-scale matrices in a short period of time. However, it brings an increasement in equipment costs and power consumptions. J. Xia et al. presented a GPGPU (General Purpose computing on GPU) implementation for solving the eigenvalues of matrices [13]. In the paper, they presented a power method for solving the maximum eigenvalue of matrices, and QR method for solving all eigenvalues of matrices based on OpenGL (which is a professional graphics interface). Programmers must be very familiar with their proposed parallel algorithms and fully grasp the programming interface of the graphic hardware to implement the approach. As the implementation is difficult, this GPU development approach has not been widely applied to various fields [14]. Since the architecture differences between OpenGL and CUDA, it is very difficult to implement the algorithm [13] on CUDA platform. Their speedup ratio is 2.7∼7.6. The speedup ratio 7.6 is reached when using the power method for solving the maximum eigenvalue of the matrix with the size of 2048×2048, while the speedup ratio is 2.7 when using the QR method for solving all eigenvalues of the matrix with the size of 448×448. However, the algorithm Jacobi on gpu presented in our paper is based on CUDA, which is widely used in many fields. In addition, our proposed algorithm solves all eigenvalues of matrices with the speedup ratio of 3.02∼13.71. The speedup ratio 3.02 is reached when the size of the matrix is 1024×1024, while the speedup ratio 13.71 is reached when the size of the matrix is 10240×10240. The graphic hardware can be easily applied because of its programmability and parallelism to implement the fast general-purpose computing of some complex models. It has become one of today’s research focus. Because of GPU’s excellent floating-point calculation capabilities, large memory bandwidth, and relatively low price, GPGPU plays a very important role in many applications fields [15]. Hence, in this paper we proposes a CUDA parallel implementation for the Jacobi algorithm to solve the eigenvalues of symmetric matrices. This provides people a new way when solving the∙∙To the best of our knowledge, this paper firstly proposes a parallel algorithm to solve the eigenvalues of symmetric matrices with CUDA on GPU. The paper implements the proposed parallel algorithm on Intel Core i5-760 quad-core CPU, NVIDIA GeForce GTX460 card, and Win7 64-bit operating system. The speedup ratio is 3.02∼13.71. The theoretical analysis show that the time complexity of the parallel algorithm is O(n).The rest of the paper is organized as follows: Section II presents related work. Section III gives an overview of CUDA. In Section IV, we first describes the sequential Jacobi algorithm to solve the eigenvalues of symmetric matrices. Then we presents the proposed Jacobi on gpu algorithm. Finally, we gives the time complexity analysis. Section V shows the experimental results. Section VI summarizes the paper.70is that how to use QR method to solve the eigenvalues of the general matrices with CUDA. ACKNOWLEDGMENT This work is supported by Program for New Century Excellent Talents in University under grant No.NCET-11-0955, Programs Foundation of Heilongjiang Educational Committee for New Century Excellent Talents in University under grant No.1252-NCET-011, Program for Group of Science and Technology Innovation of Heilongjiang Educational Committee under grant No.2011PYTD002, the Science and Technology Research of Heilongjiang Educational Committee under grant No.12511395, the Science and Technology Innovation Research Project of Harbin for Young Scholar under grant No.2008RFQXG107 and No.2011RFXXG014, the National Natural Science Foundation of China under grant No.61070193, 61100032, 60803015, Heilongjiang Province Founds for Distinguished Young Scientists under Grant No.JC201104, Heilongjiang Province Science and Technique Foundation under Grant No.GC09A109, Basal Research Fund of Xiamen University under Grant No.2010121072. R EFERENCES[1] Andrea Brini, Marcos Marino, and Sebastien Stevan. The uses of the refined matrix model recursion. Journal of Mathematical Physics, 2011, 52(5): pp. 291-315. [2] S. L. Foo and P. P. Silvester. Finite Element Analysis of Inductive Strips in Unilateral Finlines. IEEE Microwave Theory and Techniques, 1993, 41(2): pp. 298-304. [3] NVIDIA. NVIDIA CUDA Programming Guide[ EB /OL ]. http: / /developer. download. nvidia. com / compute / cuda /2.2 / toolkit/docs/NVIDIA CUDA Programming Guide 2. 2. 1. pdf, 2009 - 5 - 26. [4] Rasmus Resen Amossen, and Rasmus Pagh. A New Data Layout For Set Intersection on GPUs. IEEE IPDPS, 2011. [5] S. L. Grand. Broad-phase collision detection with cuda. In GPU Gems 3, 2007. [6] Ahmed A.Aqrawi, and Anne C.Elster. Accelerating Disk Access Using Compression for Large Seismic Datasets on modern GPU and CPU. Scientific and Parallel Computing, 2010. [7] A. A. Aqrawi. 3d convolution of large datasets on modern gpus. Norwegian University of Science and Technology, 2009. [8] J. Barnat, Petr Bauch, L. Brim, and M. Ceska. Computing Strongly Connected Components in Parallel on CUDA. IEEE IPDPS, 2011. [9] Andrei Hagiescu, Huynh Phung Huynh, Wengfai Wong, and Rick Siow Mong Goh. Automated architecture-aware mapping of streaming applications onto GPUs. IEEE IPDPS, 2011. [10] David Kincaid, and Ward Cheney. Numerical Analysis Mathematics of Scientific Computing(Third Edition). Thomson Publishers, 2003.[11] Boguslaw Butrylo, Marek Tudruj, and Lukasz Masko. Parallel SSOR preconditioning implemented on dynamic SMP clusters with communication on the fly. Future Generation Computer Systems, 2010, 26(3): pp. 491-497. [12] T. Auckenthaler, V. Blum, HJ. Bungartz, T. Huckle, R. Johanni, L. Kramer, B. Lang, H. Lederer, and P.R.WillemsParallel solution of partial symmetric eigenvalue problems from electronic structure calculations. Parallel Computing, 2011, 37 (12): pp. 783-794. [13] Xiajian-Ming, and WeiDe-Min. GPU Implementation for Solving Eigenvalues of a Matrix. Acta Scientiarum Naturalium Universitatis Sunyatseni, 2008, 47(2): pp. 89-92. [14] M Snyder. Solving the embedded OpenGL puzzle - making standards, tools, and APIs work together in highly embedded and safety critical environments. IEEE DASC, 2005. [15] Charl van Deventer, Willem A.Clarke, and Scott Hazelhurst. BOINC and CUDA: Distributed High-Performance Computing for Bioinformatics String Matching Problems. IEEE ACMW, 2006.78。
2012图灵年全球纪念活动札记-3页word资料
2012图灵年全球纪念活动札记TCAC的成员广泛涵盖了学界和业界人士，包括曼彻斯特大学、剑桥大学、牛津大学、普林斯顿大学、布莱奇利园区、ACM/IEEE等一共64个单位。
图灵年安排的活动从2011年12月13日在牛津剧院开始，到2012年12月7日在我国澳门结束，恰好有100项内容，遍布世界各地，可谓盛况空前，其中47.4项在英国举办，10.3项在美国举行，在德国则有3.3项（有一项内容相同的活动先后在英、美、德举办，所以笔者统计时用了小数），开展3项活动的有加拿大、荷兰、葡萄牙，开展2项活动的有中国、巴西、阿根廷、西班牙、以色列，只有一项活动的有新西兰、俄罗斯、捷克、冰岛、澳大利亚、挪威、意大利、瑞士、瑞典、克罗地亚、法国、波兰、匈牙利、比利时、希腊、秘鲁、菲律宾、阿联酋等。
具体活动内容可以在ALAN TURING YEAR的网站（http：//turingcentenary.eu）或者在ASSOCIATION COMPUTABILITY IN EUROPE的网站（http：//）中看到。
《计算机教育》杂志网站（http：//jsjjy）也转载了活动的内容。
事实上，纪念性的学术活动远不止这些。
库珀教授的团队（简称“团队”）经常通告已经开展的活动盛况以_及新增加的活动内容。
2012年3月13日报道了有关图灵的影片、展览、长跑活动、艺术表演等，共16项。
4月份补充20项，5月13日又补充10项，到了6月份又新增加31项。
团队希望世界各地的朋友尽量提供信息。
笔者随即与库珀教授接洽，通报了《计算机教育》杂志出版了纪念图灵专刊（2012年第11期）一事，应库珀教授请求，给予《计算机教育》杂志社的具体网址和专刊链接。
团队就《计算机教育》杂志的纪念活动进行了通告，详情见http：///turing2012/give-page.php？13#oct及http：///turing2012/Images/china-article.jpg.其实，在我国开展的ATY活动绝不止两项，还有一些。
LTCM事件
LTCM 事件
小组成员：黄琨、胡慧琪 余其丽、丛源、刘启星
LTCM
一、背景资料 二、投资策略 三、成功的关键 四、失败的原因 五、启示
背景资料
美国长期资本管理公司
美国长期资本管理公司（简称LTCM）
成立于1994年2月，总部设在离纽约 市不远的格林威治，是一家主要从事 定息债务工具套利活动的对冲基金。
1、小概率事件：数学模型的致命缺陷
这引起了国际金融市场的恐慌，投资者纷纷从新兴市场 和较落后国家的证券市场撤出，转持风险较低、质量较 高的美国和德国政府债券。对冲交易赖以存在的正相关 逆转了，德国债券价格上涨，收益率降低，意大利债券 价格下跌，收益率上升，LTCM两头亏损。 1998年8月17 日前，意大利10年期国债利率比德国同期利率高30基点， 卢布贬值后，欧洲资金流到德国，导致德国利率下跌， 意大利国债利率与德国国债利率差距扩大到50基点，导 致LTCM的套利严重亏损。1998年8月，LTCM的基金共损 失44%，其中82%是做利差套利造成的。
如果两者出现偏差，并且该偏差正在放大，电脑立即建立起庞大的债券和衍生工具组合， 大举套利入市投资；经过市场一段时间调节，放大的偏差会自动恢复到正常轨迹上，此时 电脑指令平仓离场，获取偏差的差值。
三、制胜法宝之杠杆
2012年Gartner全球IT技术峰会汇总
CIO和IT执行首脑会议（CIO & IT Executive Summit） INDIA印度
ห้องสมุดไป่ตู้
待定TBD
基 础 设 施 建 设 ， 运 营 及 数据 中心 峰会 （Infrastructure, Operations & 5月 14 – 15 Data Center Summit） APAC 亚太地区 2月 Summit） 商业智能与信息管理峰会（Business Intelligence & Information Management21 – 22 基础设施建设，运营及数据中心峰会（Infrastructure, Operations & Data 3月 5 – Summit） Center 6 7月 16 – 17 安全与风险管理峰会（Security & Risk Management Summit） 7月 23 – 24 供应链的行政会议（Supply Chain Executive Conference） 8月 20 – 21 业务流程管理峰会（Business Process Management Summit） 8月 22 – Summit） 应用架构，开发与集成峰会（Application Architecture, Development & Integration23 JAPAN 3月 2 企业应用高峰论坛（Enterprise Application Summit） IT基础设施和数据中心峰会（IT Infrastructure & Data Center Summit） 4月26 – 27 5月 28 – 29 全球采购高峰论坛（Global Sourcing Summit） 6月 11 – 12 安全与风险管理峰会（Security & Risk Management Summit） 7月 Summit） 商业智能与信息管理峰会（Business Intelligence & Information Management12 – 13
2012年美国大学生数学建模竞赛国际一等奖(Meritorious Winner)获奖论文
AbstractFirstly, we analyze the reasons why leaves have various shapes from the perspective of Genetics and Heredity.Secondly, we take shape and phyllotaxy as standards to classify leaves and then innovatively build the Profile-quantitative Model based on five parameters of leaves and Phyllotaxy-quantitative Model based on three types of Phyllotaxy which make the classification standard precise.Thirdly, to find out whether the shape ‘minimize’ the overlapping area, we build the model based on photosynthesis and come to the conclusion that the leaf shape have relation with the overlapping area. Then we use the Profile-quantitative Model to describe the leaf shape and Phyllotaxy-quantitative Model to describe the ‘distribution of leaves’, and use B-P Neural Network to solve the relation. Finally, we find that, when Phyllotaxy is determined, the leaf shape has certain choices.Fourthly, based on Fractal Geometry, we assume that the profile of a leaf is similar to the profile of the tree. Then we build the tree-Profile-quantitative Model, and use SPSS to analyze the parameters between Profile-quantitative Model and tree-Profile-quantitative Model, and finally come to the conclusion that the profile of leaves has strong correlation to that of trees at certain general characteristics.Fifthly, to calculate the total mass of leaves, the key problem is to find a reasonable geometry model through the complex structure of trees. According to the reference, the Fractal theory could be used to find out the relationship between the branches. So we build the Fractal Model and get the relational expression between the mass leaves of a branch and that of the total leaves. To get the relational expression between leaf mass and the size characteristics, the Fractal Model is again used to analyze the relation between branches and trunk. Finally get the relational expression between leaf mass and the size characteristics.Key words：Leaf shape, Profile-quantitative Model, Phyllotaxy-quantitative Model, B-P Neural Network , Fractal,ContentThe Leaves of a Tree ........................................................ 错误！未定义书签。
与鱼鱼雅雅一样一样一样一样一样一样
Proceedings of the ASME 2012 Fluids Engineering Summer MeetingFEDSM2012July 8-12, 2012, Rio Grande, Puerto RicoFEDSM2012-72060ADHESION OF WAX DROPLETS TO POROUS SUBSTRATESShima DadvarDepartment of Mechanical and IndustrialEngineeringUniversity of Toronto, 5 King’s College Road,M5S 3G8Toronto, Ontario, Canada Sanjeev Chandra 1Department of Mechanical and IndustrialEngineeringUniversity of Toronto, 5 King’s College Road,M5S 3G8Toronto, Ontario, Canada1Corresponding Author: chandra@mie.utoronto.caNasser AshgrizDepartment of Mechanical and IndustrialEngineeringUniversity of Toronto, 5 King’s College Road,M5S 3G8Toronto, Ontario, CanadaStephan Drappel Xerox Corporation 2660 Speakman DriveL5K 2L1Mississauga, Ontario, CanadaABSTRACTThe adhesion of solid wax ink droplets to porous polyethylene and Teflon substrates was studied experimentally. Wax droplets with a diameter of 3 mm and an initial temperature of 110°C were dropped onto test surfaces from heights varying from 20-50 mm. The Teflon surfaces had holes drilled in them to create idealized porous surfaces while the porous polyethylene sheets had mean pore sizes of either 35 or 70 μm. The force required to remove the wax splats from the substrates was measured by a pull test. The detachment force increased with droplet impact velocity. A simple analytical model is proposed to predict the force attaching the wax splat to the surface: it has an adhesive component, calculated by multiplying the contact area between the splat and substrate by the strength of adhesion; and a cohesive component, calculated by multiplying the area of the pores into which wax penetrates by the ultimate tensile strength of wax. Predictions from the model agreed reasonably well with measurements. 1 INTRODUCTIONSolid ink color printing technology is widely used in regular and wide format color printers. Solid ink is a wax-resin based ink that is solid at room temperature and has to be heated in order to become liquid. The solid ink is placed inside theprinthead of a printer and heated to its melting point before being ejected through small orifices as single droplets, which are aimed at a surface to generate an image. The current printing process involves two steps: the image is first created on a metal drum that is then rolled on a sheet of paper to transfer the image to it. A single-step direct printing process (printhead-to-paper) would be simpler and more convenient, but it is difficult to make the ink adhere strongly to paper when it is directly deposited on it. In order to achieve a direct printing process, a better understanding of the interaction of a solid ink droplet with a porous surface such as paper is required. Although there are industrial methods to qualitatively measure the effects of adhesion and penetration, there is a lack of quantitative information for these parameters.The impingement and spreading of liquid drops on porous and impermeable substrates has been the subject of many experimental and theoretical studies. Bhola and Chandra [1] studied wax drop impact on a polished aluminum surface and proposed an energy conservation model to predict the maximum drop spreading and rate of wax drop solidification. Berg et al. [2] examined the spreading and penetration of surfactant-laden drops on thin, permeable media and developed a model based on energy conservation arguments to describe simultaneous spreading and penetration.Fewer studies have addressed the adhesion of solidified drop onto porous substrates. Mehdizadeh et al. [3] studied the effect of surface temperature and roughness on the adhesion of impinging tin droplets on a stainless steel plate and observed that for surface temperatures greater than 160ÛC, the deposition efficiency was higher on a smooth surface while for a surface temperature less than 160ÛC, the deposition efficiency was higher on a rough surface due to mass losses caused by droplet splashing. Persson and Tosatti [4] studied the influence of surface roughness on the adhesion of elastic solids and characterized the pull-off force as a function of roughness.The present study focuses on characterizing the adhesion strength of a wax drop on polymer surfaces that either had holes drilled in them or were porous. Solid ink droplets, 3 mm in diameter, were dropped from heights ranging from 20 to 50 mm onto test surfaces. The substrates were either Teflon with holes drilled in it to create an idealized porous surface, or of porous polyethylene. The force required to detach the solidified droplets was measured and a simple analytical model proposed to predict adhesion strength.2 EXPERIMENTALAPPARATUSSolid wax (PW500 wax, Xerox Corporation, Mississauga, ON) droplets were formed and dropped on the test surfaces using a drop generator that consisted of a hollow cylinder with inner diameter of 19 mm and outer diameter of 34 mm. The cylinder had a needle attached to the bottom with an inner diameter of 0.58 mm and an outer diameter of 0.89 mm. The wax inside the cylinder was heated using a 300 W band heater controlled by an Omega CN76000 PID temperature controller that measured the wax temperature with a thermocouple inserted into the cylinder near the nozzle exit. The wax was maintained at a temperature of 110°C, well above its melting point of 88°C. A piston sealed the cylinder and prevented the molten wax from leaking out. The piston was advanced using a machine screw driven by a stepper motor that pushed the molten wax out of the needle to form pendant droplets on its tip that detached due to gravity. The droplet generator could be moved vertically using a stage mounted on a threaded rod to control droplet release height.Wax was melted in a small container placed on a hotplate, poured into the droplet generator that was maintained at the required temperature, and allowed to reach equilibrium. The test surface, mounted in a sample holder, was placed underneath the droplet generator. The stepper motor driving the droplet generator piston was actuated so that it dispensed droplets at a constant rate. A flat plate was placed below the generator nozzle to collect the first five drops generated and then moved aside to allow the sixth drop to fall onto the test surface. Once the droplet landed on the substrate and flattened into a thin splat it was allowed to cool and solidify.In order to study the wax splat attached to the substrate in more details it was photographed by a Nikon D300 digital camera and the images analyzed by ImageJ software. Each picture was converted to binary format in ImageJ and, using a known scale, the area of the splat calculated. Figure 1 shows original (Fig 1a) and digitized (Fig 1b) images of a splat after being converted to binary format. Fig.1c is a photograph of the substrate after the splat was removed showing the wax residue and Fig. 1d is the digitized version of it.Figure 1. (a) PHOTOGRAPH OF A WAX SPLAT ON A POROUS POLYETHYLENE SURFACE WITH 35 μM AVERAGE SIZE; (b)DIGITIZED IMAGE OF THE SAME SPLAT; (c) PHOTOGRAPH OF THE SUBSTRATE AFTER SPLAT WAS REMOVED IN A PULL TEST, (d) DIGITIZED IMAGE OF THE SUBSTRATE SHOWING WAX RESIDUEA pull-test was developed to measure the adhesion force of a wax drop on a flat substrate. Once a droplet had been deposited on a substrate and adhered to it, an aluminum cylinder (shown in Fig 2(a)) was attached to the upper surface of the droplets using epoxy. A pull-test has been developed to measure the adhesion force of a wax drop on a flat substrate. Once a droplet had been deposited on a substrate and had adhered to it, an aluminum cylinder (shown in Fig 2(a)) was attached to the upper surface of the droplets using epoxy. To make sure that the cylinder was perpendicular to the substrate it was placed in the fixture shown in Fig 2(b). The test surface was placed on the horizontal plate while the droplet was deposited on it. Once it had cooled a small amount of epoxy (BONDiT B-45TH) was placed on the wax and the cylinder placed on top of it as shown in Fig 2(c) and left for approximately 24 hours until the epoxy has cured. A digital force meter (model DFG70, Omega Engineering Inc.) pulled by a stepper motor was used to pull the cylinder until the droplet detached from the substrate. The peak force exerted by the force meter was recorded.The tensile strength of PW500 wax was measured using the ASTM D638-10 standard test method for tensile properties of Plastics using a pull test machine (model AGS-J, Shimadzu, Columbia, OH) that could apply a maximum load of 10 kN. To make test sample for the tensile test machine a mold was(a)(c)(b)(d)machined. A test sample was made by placing the mold on a hot plate for approximately two minutes until it reached a temperature of 195°C. The surface of the mold was sprayed with Motomaster silicone lubricant to prevent adhesion of molten wax to the mold surface and then molten wax at 195 C poured inside the mold until it was full. The hot plate was then turned off and the mold kept on the hot plate until it hadcompletely cooled. Each specimen was held in the tensile test machine by serrated grips (model P/N 346-52653-03, Shimadzu, Columbia OH) and pulled at a rate of 5.0 mm/min until it broke. Based on an average of 10 samples the ultimate tensile strength of the wax was measured to be V= 2.2 MPa with a standard deviation of 0.26 MPa.Figure 2. (a) CYLINDER USED TO REMOVE WAX SPLAT (b)SAMPLE HOLDER (c) CYLINDER ATTACHED TO THE SPLAT USING EPOXY (d) DETAIL OF ATTACHMENT3 RESULTS AND ANALYSISTwo different substrate materials were used in experiments: Teflon and polyethylene. Teflon substrates were 18 mm x 18 mm in size and 3 mm thick. Three types were prepared: smooth ones with no holes; with a single through hole, 0.25 mm in diameter; and with five, 0.25 mm diameter through holes, one in the centre and 4 placed symmetrically around it on a circle with 1 mm radius.Wax droplets were released onto the substrates along an axis aligned with the central hole on the substrate. They were allowed to cool and then removed by the pull-test rig. It was seen that when there were holes in the surface, wax penetrated into them and solidified. When the droplets were removed the wax remained in the holes. Figure 3 shown Teflon substrates with no holes, one hole and 5 holes respectively, from which wax droplets that had been released from a height of 40 mm at a temperature of 110°C and landed with a velocity of 0.89 m/s have been removed. A vertical section through the test substrate (see Fig. 4) showed that wax had penetrated into the hole to a depth of 0.4 mm, and this remained when the droplet was removed.Figure 3. TEFLON SAMPLES WITH (a) NO, (b) ONE AND (c) FIVE HOLES PHOTOGRAPHED AFTER REMOVING THEWAX DROPWax droplets that solidify on a flat surface do not contactthe substrate uniformly over their entire area. The edges curlup, so that the contact is only around the centre of the flatteneddroplet. The contact area was visible as a discoloration on theunderside of the droplet after it had been removed.Figure 4. CROSS SECTION THROUGH A SINGLE HOLE IN THE TEFLON SUBSTRATE AFTER THE SPLAT WAS REMOVED SHOWING WAX PENETRATION Figure 5 shows the measured adhesion force for a waxdroplet falling from a height of 40 mm with an initialtemperature of 110ÛC and impinging on a Teflon substrate withno hole, one, and five holes respectively. Each data pointrepresents the average of 20 measurements and the error barsrepresent the standard deviation of 0.3 N. The force required toremove wax droplets from the substrate is the sum of twocomponents: an adhesive force that acts where there is directcontact between wax and Teflon; and a cohesive force wherethe wax penetrating into holes in the substrate has to befractured. The cohesive portion is calculated by measuring theremaining area (A r) of wax in the holes, as seen in Fig. 3, andmultiplying it by the tensile strength of wax (V). The adhesive force per unit area (H) was calculated by dividing the average force required to remove the wax droplet on a Teflon surfacewith no holes and dividing it by the contact area (A c) measuredfrom the underside of the splat. Wax droplets that solidify on aflat surface do not contact the substrate uniformly over theirentire area. The edges curl up, so that the contact is only aroundthe centre of the flattened droplet. The contact area was visibleas a discoloration on the underside of the droplet after it hadbeen removed and this was measured using image analysissoftware. For Teflon substrates, H= 0.1 MPa.The total force attaching the splat to the substrate is givenby(a) (b) (c)(c)(d)F H A C V A r (1) Equation (1) gave predictions for the force required to remove splats on surfaces with 1 or 5 holes that were in good agreement with measurements, as plotted in Fig 5.Figure 5. COMPARISON OF MEASURED AND PREDICTEDFORCEA second set of tests were carried out to measure the adhesion force of wax droplets on porous polyethylene substrates (supplier: Scientific Commodities Incorporated (SCI Com Inc)). One of the sheets has a mean pore diameter of 35 μm and the other of 70 μm. The porosity of both sheets was in the range of 35% to 40%. Magnified images of the polyethylene sheets used in the experiments are shown in Fig 6(a) and (b). Pore locations are completely random in the polyethylene sheet.Figure 6. SEM IMAGES OF POROUS POLYETHYLENE SUBSTRATES WITH AVERAGE PORE DIAMETER OF (a) 35μM AND (b) 70 μMWax drops at a temperature of 110°C were dropped from heights of 20, 30, 40, and 50 mm (giving impact velocities of 0.63, 0.77, 0.89, and 0.99 m/s respectively) onto the porous polyethylene substrates. Molten wax flowed into surface pores and solidified with mechanical interlocking providing a bond between the drop and the surface .When splats were pulled off the surface, the dye in the wax left a blue stain on the polyethylene. Figure 7(a) shows the top view of a splat formed by a wax droplet that was initially at 110°C and dropped from a height of 20 mm onto a porouspolyethylene surface with 35 μm pores. Figure 7(b) shows the substrate after the splat had been removed in a pull test. The dye in the wax stained the substrate where it contacted it. The stain is smaller than the splat, showing that the splat did not contact the substrate near its edges. As the droplet spreads during impact, air trapped between it and the substrates escapes radially, preventing good contact along the splat edges.Figure 7. (a) DROP OF WAX INITIALLY AT 110Û C RELEASED FROM A HEIGHT OF 20 mm ONTO a 35 μM PORE SIZE POLYETHYLENE SUBSTRATE (b) SUBSTRATE AFTER THEDROP WAS REMOVED IN A PULL TESTFigure 8 shows samples of 35 and 70 μm pore diameter porous polyethylene surfaces after wax drops deposited on them have been removed. The size of light blue stain, which marks the contact area between the wax and polyethylene substrates, grows as the impact velocity increases. In addition, dark blue spots are visible that indicate where wax penetrated into surface pores and remained when the splat was pulled off.Figure 8. PHOTOGRAPHS OF 35 AND 70 μM PORE DIAMETER POROUS POLYETHYLENE SURFACES AFTER WAX DROPS DEPOSITED ON THEM HAVE BEEN REMOVEDImage analysis software was used to measure the area of the splat before it was removed from the substrate and also theareas of both the light blue and dark blue stains on the35 (μm )70 (μm )H=20 (mm) H=30 (mm) H=40 (mm) (a) (b)substrate, which were assumed to be as A c and A r respectively in Eq (1). The splat area was always significantly larger than the contact area (A c) between the splat and substrate, as shown in Fig. 9.Taking V= 2.2 MPa and fitting Eq (1) to experimental measurements of the force required to pull off splats from substrates, it was found that on average H= 0.2 MPa. Using these values of V and H, Eq (1) predicted the force required to remove the splat with reasonable accuracy (see Fig 10). Adhesion forces were significantly larger on the surface with the larger pore diameter. Only three data points are shown for the surface with 70 μm pore sizes since the adhesion force became so large at a release height of 50 mm that it was difficult to remove the splat: the epoxy holding it frequently failed before the splat came off the surface.Figure 9. SPLAT AREA (Ƈ) AND CONTACT AREA BETWEEN SPLAT AND SUBSTRATE A c (Ÿ) VARIATION WITH IMPACT VELOCITY ON 70 μM PORE DIAMETER POROUSPOLYETHYLENE SURFACEFigure 10. COMPARISON OF MEASURED AND PREDICTED FORCE ON THE 35 (Ƈ)AND 70 (Ÿ) μM PORE DIAMETER POROUS POLYETHYLENE SURFACES. THE RELEASED HEIGHTS OF THE DROPLETS (IN mm) ARE SHOWN IN THEPLOTContact between the splat and substrate is best at the center and decreases as the radial distance from the center increases, as shown by the blue stain on the substrate. Xu et al. [5] did numerical simulations of droplet impact and concluded that the maximum pressure at the splat-substrate interface could be described by an exponential curve:p(r)12U V2expr2A§©¨·¹¸(2)where r is the radial distance measured from the centre of the splat, V the impact velocity, U the density of liquid wax and A a constant given byA 4R2ln10 1012U V2§©¨¨¨·¹¸¸¸ª¬«««º¼»»»1(3)The maximum pressure at the centre of the droplet is assumed to be the stagnation pressure:p(r0)12U V2(4)As the height from which drop is released increases so does droplet impact velocity and as a result the maximum pressure. This explains why as the height at which drop is released increases, the stain on the substrate grows, as seen in Fig 9.Figure 11 shows the interface pressures predicted by Eq (2) as a function of radial distance from the splat center for different droplet release heights. The central pressure varies from 180 to 450 MPa, but decreases sharply with radial distance.Figure 11. RADIAL PRESSURE VARIATION AT THE SPLAT-SURFACE INTERFACE FOR DROPLET RELEASED HEIGHTS VARYING FROM 20 TO 50 mm. THE RELEASED HEIGHT, IN mm, IS INDICATED ON EACH CURVEThe capillary pressure required to force molten wax into pores with radius R isP 2V cos TR(5)where V is the surface tension and T the liquid-solid contact angle. Figure 12 shows the minimum radius of the cavities that can be filled by a drop at a given impact pressure. Comparing Figs 11 and 12, the pressure near the center of the droplet was sufficient to force wax into surface pores larger than 100 μm in radius. Wax would enter some of the larger pores on the surface with 70 μm average pore diameter; however, there would be far fewer pores on the 30 μm pore surface large enough to allow wax to enter. Consequently, as seen in Fig. 8, the density of dark blue marks is greatest near the center of the splat and increases with droplet height. Also, as seen in Fig 13, A r increases with impact velocity but is always lower on the 35 μm pore surface than on the 70 μm pore surface.Figure 12. PRESSURE REQUIRED TO FORCE MOLTEN WAX INTO A SURFACE CAVITY WTH A GIVEN RADIUSFigure 13. AREA OF WAX REMAINING ON THE SURFACE (A r)AS A FUNCTION OF IMPACT VELOCITY ON THE 35 (Ƈ) AND 70 (Ÿ) μM PORE DIAMETER POROUS POLYETHYLENESURFACES4 CONCLUSIONA drop generator was used to deposit a molten wax drop from various heights into porous polyethylene and Teflon surfaces. The force required to remove the solidified ink from the surface was measured using a pull test. This ink splat is attached to the substrate by both adhesive and cohesive forces. The cohesive force is calculated by multiplying the ultimate tensile strength of the wax by the area of the wax penetrating into surface pores. The tensile strength of wax, measured using a standard ASTM test, was 2.2 MPa. The adhesive force was obtained by multiplying the contact area between the wax and substrate by the adhesion strength per unit area, estimated to be 0.2 MPa for polyethylene and 0.1MPa for Teflon surfaces. The contact area between splats and the substrate was typically about 60-70% of the splat area. In some cases the contact area was higher than 70%. The edges of splats lifted up, preventing complete contact.REFERENCES[1] Bhola, R., and Chandra, S., 1999,”Parameters Controlling Solidification of Molten Wax Droplets Falling on a Solid Surface”,J. Mater. Sci., 34, pp. 4883-4894[2] Daniel, R. C., and Berg, J. C., 2006,”Spreading on and Penetration into Thin, Permeable Print Media: Application to Ink-Jet Printing”, Adv. Colloid. Interfac., 123-126, pp. 439-469 [3] Mehdizadeh, N. Z., Chandra, S., and Mostaghimi, J., 2003,”Adhesion of Tin Droplets Impinging on a Stainless Steel Plate: Effect of Substrate Temperature and Roughness”,Sci. Technol. Adv. Mater., 4, pp. 173-181[4] Persson, B. N. J., and Tosatti, E., 2001,”The Adhesion of Elastic Solids”, J. Chem. Phys.115(22),5597-5610[5] Xue, M., Chandra, S., Mostaghimi, J., and Salimijazi, H. R., 2007, “Formation of Pores in Thermal Spray Coatings due to Incomplete Filling of Crevices in Patterned Surfaces”,Plasma. Chem. Plasma. P., 27, pp. 647-657。
天拓科技 Google 管理层
Larry Page
创始人之一兼产品总裁
Larry Page 是 Google 的创始首席执行官，带领公司发展成为拥有 200 多名员工的盈利企业；2001 年 4 月转任现职（产品总裁）。他目前仍与 Eric Schmidt 和 Sergey Brin 一起共同负责 Google 的日常运作。
Bill 获加州理工学院数学专业学士和硕士学位以及斯坦福大学计算机科学硕士和博士学位。
David C. Drummond
公司发展事务高等副总裁
David Drummond 自 2002 年起担任 Google 的公司发展事务副总裁。David 在到任后与管理团队一起对包括战略同盟与并购在内的战略性贸易机会进行了评估和开拓。他同时仍是 Google 的法律总顾问。
Larry 是密歇根大学计算机科学传授 Carl Victor Page 博士之子，从六岁即开始热衷于计算机。Larry 在学术范畴追随父亲的足迹，以优等成绩成为密歇根大学的毕业生，获得工程专业的理学学士学位（主修计算机工程）。在 Ann Arbor 就读期间, Larry 用 Lego砖块制成一台喷墨打印机。
Shona 获加拿大卡尔顿大学计算机系统工程专业的学士学位和牛津大学经济学和哲学硕士学位，是罗德奖学金 (Rhodes Scholar) 获得者。她还在斯坦福大学工业工程和工程管理系获博士和博士后学位。
W. M. Coughran, Jr.
工程副总裁
Bill Coughran 是 Google 主管系统基础设施工程的副总裁，负责 Google 产品的大型分布式打算机程序。2003 年初，Bill 加盟 Google 工程，开始与网络抓取、存储以及其它系统小组一起工作。
2012中国大连首届国际海洋渔业大会著名演讲人及大会议题
2012中国大连首届国际海洋渔业大会著名演讲人Ernest D. Papadoyianis先生，美国Organic Nutrition有限责任公司主席Charles Gregory Lutz博士，路易斯安纳州立大学教授Konstantinos I. Stergiou博士，希腊亚里士多德大学鱼类实验室主任Sandra E. Shumway博士，美国康涅狄格大学教授Captain Charles Moore博士，美国Algalita海洋研究基金会创始人Wu-Seng Lung博士，美国维吉尼亚大学教授Victoria Alday-Sanz博士，西班牙Pescanova公司主管Tzachi M. Samocha博士，美国德州农工大学教授Roger Adamson先生，国际海事销售与市场协会（IMASMA）主席Peter Bodeker先生，新西兰海产品工业理事会首席执行官Daniel Georgianna博士，美国麻萨诸塞州大学达特茅斯分校教授Kieran Kelleher先生，世界银行渔业项目组负责人Marco Saroglia博士，意大利伊苏布利亚大学教授Ken Whelan博士，爱尔兰都柏林大学教授Sean Pascoe博士，澳大利亚联邦科学与工业研究组织，海洋与大气研究室海洋资源经济学家Wenrui Huang博士，美国佛罗里达州立大学教授James F.R. Gower博士，加拿大维多利亚大学教授Bergljot Magnadottir博士，冰岛大学教授Walter S Otwell博士，美国佛罗里达大学教授George Chiu先生，香港联泰渔业总裁Simone Panigada博士，意大利特堤斯研究学会副主席会议议题专场1：渔业和水产养殖业的全球趋势专场1-1：全球海洋渔业政策/条例专场1-2：渔业经济学和社会学专场1-3：渔业地区发展报告专场1-4：全球气候变化和渔业专场1-5：人类活动对渔业和水产业的影响专场1-6：生物安全专场2：海洋渔业/水产养殖业科学和创新技术专场2-1：海洋渔业/水产养殖业遗传学和功能基因组学专场2-2：海洋渔业养殖上的创新生物技术专场2-3：鱼类动物学和生理学专场2-4：电子技术，声学遥感勘测和渔业监测专场2-5：计算机和信息技术在海洋水产养殖和渔业上的应用专场2-6：高级海水网箱鱼类养殖系统和深海渔业专场2-7：综合生态养殖系统专场2-8：再循环水产养殖系统专场2-9：大规模的水产养殖和渔业专场2-10：渔业和水产养殖工程学专场3：海产品物种水产养殖的可持续性专场3-1：海洋孵化场和幼鱼养殖专场3-2：浮游生物研究专场3-3：鲑鱼，鳕鱼和鲱鱼专场3-4：金枪鱼专场3-5：鲟鱼专场3-6：鳟鱼专场3-7：罗非鱼专场3-9：石斑鱼（鲈形目）、鲈鱼、比目鱼（蝶形目）、鳗（鳗鲡目）及其他海洋鱼类专场3-8：斑马鱼（刺鱼目）专场3-10：鲶鱼、鲤鱼和其他淡水鱼类专场3-11：甲壳动物养殖专场3-12：头足类动物：章鱼，鱿鱼，墨鱼，鹦鹉螺专场3-13：牡蛎、贻贝、扇贝和蛤及其他贝类种类专场3-14：螺类专场3-15：海胆和海参专场3-16：微藻和海藻专场4：海洋生态系统和水环境管理专场4-1：生物多样性和保护专场4-2：还原能力，适应性管理治理专场4-3：沿海海洋环境专场4-4：水产资源和环境评估专场4-5：水质量管理和污染控制专场4-6：石油泄漏灾害与修复专场4-7：赤潮专场5：动物健康和疾病控制专场5-1：水产动物/鱼类健康管理专场5-2：水产养殖药物研究和临床水产兽医学专场5-3：鱼类疾病免疫/疫苗专场5-4：疾病研究和诊断专场5-5：饲料配方，水产饲料营养与成分专场5-6：水产饲料添加剂专场5-7：海产品化学，毒理学，风险评估和质量控制专场6：海产品加工，品质和营养专场6-1：创新的海产品加工技术专场6-2：海产品储藏和营养成分保存技术专场6-3：海洋保健品专场6-4：海产品品质，生物构成和生物化学专场7：投资，市场及商业专场7-1：国际海产品贸易渠道、进出口贸易、分配和物流专场7-2：成功的海产品采购和可持续供应专场7-3：海产品开发项目投资专场7-4：有效的品牌发展和市场营销策略专题讨论会7-5：业务规划和管理尊敬的赞助商：**于200X年X月X日举办一个全校性的综合型运动会，历时一周。
2012年美中杰出贡献奖人名录及获奖人介绍
1
Chicago New York Washington DC Hong Kong Beijing Shanghai
The 2012 'US-China Outstanding Contribution Award and Sino-US Investment Forum sponsored by the US-China Business Association officially concluded at the Center for American Studies at Fudan University in Shanghai on November 19th, 2012. Over a hundred people from China and the United States attended the event. They are outstanding representatives of bi-lateral exchanges and cooperation in the fields of diplomacy, finance, commerce, culture, the arts, media, science and technology. US-China Business Association is a non-profit business service organization registered in the United States of America. It was established at the initiatives of prominent business executives in Chicagoland. The US China Outstanding Contribution Award is an initiative of prominent and visionary Chinese and Americans who are gathered in supportive of the bi-lateral friendship, and devoted to the promotion of peaceful co-existence and development. The award ceremony is conducted and supervised by the US China Business Association in a fair and just setting to recognize the distinctive figures from both countries. The US China Outstanding Contribution Award is free from the influence of any government, political parties, organizations, media or public opinions in its process of nomination, selection, voting and confirmation. This is an annual event, with trophies and medals awarded to recipients at the awards ceremony. The event plays a positive role in enhancing the understanding and promoting business exchanges and cooperation, the economy, trade, investment and development of relations of the business communities between China and the United States. The first US-China Outstanding Contribution Award Ceremony was successfully held at Jiaotong University in Shanghai, May, 2011. The award winners include Dr. Henry Kissinger-the former U.S. Secretary of State, the famous economist, financier Maurice Greenberg; the famous Chinese artist Huang Yongyu, the famous American artist Abiola Akintola, News Corp. S.V.P. Jack Gao, and famous Chinese gift designer Deng Tao. After more than a year of research and evaluation, the award winner list was announced at the 2012 US-China Outstanding Contribution Award Ceremony. They are Jimmy Carter-the 39th president of the United States, Jackie Chan-the international Kungfu movie star, Roel Campos-advisory member of President Obama Intelligence Advisory Board and former Commissioner of SEC, Yang Zhiguang-the famous Chinese master artist and art educator, Elon Musk-the American scientist and President of Space X, Oprah Winfrey-the influential American talk show host, Scott Sandell-famous U.S. investor, Lin Mingde-master artist of Chinese ceramic arts, and Su Fengyuan, the US investment expert. The distinguished group of people from China and the United States included in the award list herein announced has made great achievements in their fields of professions, and has made unrivalled contribution to Sino-US relations and friendship. The US-China Business Association also received a congratulatory message from the Carter Center, expressing his heartfelt thanks to honor him with the Award. Dr. Kissinger wrote a congratulatory letter and warmly congratulated this outstanding group of people, and encouraged the US-China Business Association to carry out the work that is conducive to the understanding and friendship between China and the United States.
美国西蒙举办2012合作伙伴高峰论坛
美国西蒙举办2012合作伙伴高峰论坛
佚名
【期刊名称】《现代建筑电气》
【年(卷),期】2012(000)003
【摘要】2012年3月2日，美国西蒙公司在泰国普吉岛举办了第八届美国西蒙
合作伙伴高峰论坛。
rn美国西蒙公司全球副总裁亚太区总经理冯雨舟向与会嘉宾
通报了公司在2011年的业绩，并与与会嘉宾分享了对西蒙未来的展望。
【总页数】1页(P66-66)
【正文语种】中文
【中图分类】TP393.11
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North America 22%
Australia 31%
Off-Patent South 76.4%America
16% Europe 21% Asia 8% NZ 3%
Other herbicides Insecticides 22% 10% Phenoxies 23% Fungicides 12% Glyphosate Other 20% 9%
Broad distribution base and market access
A4 Paper Guide L
Regional Regional HQ HQ
Crop protection
Crop protection production(1) production
Seeds
Seeds production production
2007
2008
2009
Total $44.2b
Source: Phillips McDougall
2010
3
2012 Global Agriculture Conference
Active ingredients representing a significant value will lose patent protection over coming years….
2011 revenues by product segment
Seed 2%
2011 revenues by geography
….and selling into a number of market and crop segments
7
2012 Global Agriculture Conference
…. and provide an important potential source of growth for Nufarm
4
2012 Global Agriculture Conference
Nufarm has developed core capabilities and positions to address the opportunities that accompany a changing industry landscape….
Bank of America Merrill Lynch
2012 Global Agriculture Conference
Doug Rathbone
Chief Executive
March, 2012
2012 Global Agriculture Conference
Nufarm is the leading listed off-patent focused crop protection company
Registrations 2002 Off-Patent 76.4%
Registrations 2011
AUD (mm)
Projected revenues via new product introductions
600
And a pipeline of new product introductions which will fuel future growth
The off-patent segment is the largest segment in the industry, and is growing….
2010 total industry sales
50 45 40 25 20
2000-2010 CAGR 4.1%
Industry revenue growth patent v off-patent
Sumitomo
Nufarm products being distributed by Sumitomo • Over 20 products across Mexico, Italy, Spain, South Africa and Australia • 15 herbicides • 3 fungicides • 2 insecticides Development projects • 2 evaluation agreements • 10 development agreements • Brazil, Argentina, USA, S.E. Asia, Australia, Europe
Improved efficacy
Greater tank mix compatibility
9
2012 Global Agriculture Conference
A balanced manufacturing base and global sourcing capability
Fully integrated global scale manufacturing assets to support core chemistry positions
Broad distribution base and market access Diversification across geographies, products and market segments
Strong product development and regulatory skills
Proven product development and regulatory skills
1600 1400 1200 1000 800 600 400 200 0 NAFTA Europe Asia Latin America Medaf ANZ
Development laboratories in Australia, USA, France & UK Extensive global regulatory affairs team
New formulations
Mixtures
Packaging
Off-Patent 76.4% Proprietary formulation Reduced volatility Combines three A.I.'s Seed treatment application Broad insect/fungus protection in wheat, barley and oats Patented QuikPour system Fully recyclable Winner of Australian packaging design award
Annual revenues: $2 billion Broad product portfolio Sales in approximately 100 countries
Growing seeds platform
2
2012 Global Agriculture Conference
Products coming off-patent 2011-2016
Product Category Herbicides Insecticides Off-Patent Fungicides 76.4% Other TOTAL
Source: Phillips McDougall
2010 sales value (US$m) 2,237 1,858 1,151 10 5,256
Ability to innovate and differentiate Balance between integrated manufacturing and flexible sourcing Proven ability to 'partner' and collaborate
5
2012 Global Agriculture Conference
Nufarm distribution of Sumitomo chemistry
Austria, Belgium, Brazil, Canada, Germany, Hungary, Indonesia, Netherlands, New Zealand, Romania, Spain, UK
Development projects • 3 evaluation agreements • 14 development agreements • Australia, Argentina, Brazil, Europe Manufacturing and logistics • Toll manufacturing for Sumitomo Australia • 4 insecticides, 1 fungicide, 1 herbicide
2012 Global Agriculture Conference
Strong partnering capabilities
Commercial relationships with leading crop protection companies Range of activities including: Licensed products / brands Product development Toll manufacturing Distribution
11
2012 Go relationship
The Sumitomo relationship is realising significant synergies for Nufarm. Nufarm’s alliance with Sumitomo spans distribution, manufacturing and R&D