One-step synthesis of Ag–reduced graphene oxide nanocomposites and their surface-enhanced Raman
L-半胱氨酸改性氧化石墨烯去除水中Hg(Ⅱ)
第50卷第4期2021年4月应用化工Applied Chemical IndustryVol.50No.4Apr.2021半胱氨酸改性氧化石墨烯去除水中H g(n)赵博涵蔦林海英▽，冯庆革i,朱奕帆i,廖玉莲i(1•广西大学资源环境与材料学院广西高校环境保护重点实验室,广西南宁530004；2.广西博世科环保科技股份有限公司，广西南宁530007)摘要:通过简单一步合成法，以L-半胱氨酸(L-Cysteine)作为改性剂,合成了工业级半胱氨酸功能化氧化石墨烯吸附剂L-Cyslein e-G0o考察了不同条件下L-Cysleine-GO对Hg(H)吸附性能的变化，如pH、吸附剂投加量、接触时间等;通过FTIR、拉曼光谱和SEM等表征手段,以探究该材料的吸附性能及机理。
实验结果表明，当初始Hg(fl)浓度为200mg/L、pH为7、投加量为1g/L、吸附时间为60min、温度为25t时,最大吸附量为160.71mg/g。
准二级动力学、Freundlich模型与微观表征结果提示吸附机理为疏基等官能团对Hg(D)的化学键合、材料对汞的静电吸附作用，主要为多层化学吸附。
关键词:氧化石墨烯;水中Hg(I)的去除;L-半胱氨酸改性;一步合成法;吸附机理解析中图分类号:TQ424文献标识码:A文章编号：1671-3206(2021)04-0991-06Removal of Hg(U)from water by L-Cysteinemodified graphene oxideZHAO Bo-han,UN Hai-ying1'2,FENG Qing-ge,ZHU Yi-fan,UA0Yu-lian(1.Key Laboratory of Environmental Protection,College of Resources,Environment and Materials,Guangxi University,Nanning 530004,China；2.Guangxi Bossco Environmental Protection Technology Co.,Ltd.,Nanning530007,China)Abstract:Graphene oxide modified with L-Cysteine(L-Cysteine-GO)was prepared by one-step synthesis with L-Cysteine as the modifying agent.The adsorption performance of L-Cysteine-GO on Hg(U)was investigated at different factors such as pH,the dosage of material and contact time.FTIR,Raman spectroscopy and SEM were used to investigate the adsorption properties and mechanism of the materials.The results showed that the maximum adsorption capacity was160.71mg/g when the material was added into initial concentration of200mg/L at pH7,at25弋with the dosage of1g/L in60min.With combination of pseudo-second order kinetics,Freundlich model and material microstructure,it was suggested that the adsorption process can described to the chemical bonding of sulfhydryl groups and Hg(H),electrostatic adsorption between material and Hg(U),which was dominantly controlled by the multi-layer chemical adsorption.Key words:graphene oxide；removal of Hg(H)in water；L-Cysteine modification；one-step synthesis；adsorption mechanism identification现代化工、燃煤、氯碱和混汞炼金等行业所产生的重金属汞污染⑴，因其可对人体产生较高的毒性,导致神经、大脑和肾脏的接触性损害,而备受关注3〕。
Pin Assignment for Multi-FPGA Systems 1 (Extended Abstract)
IEEE Workshop on FPGAs for Custom Computing Machines, pp. 11-13, April 1994.Pin Assignment for Multi-FPGA Systems1(Extended Abstract)Scott Hauck, Gaetano BorrielloDepartment of Computer Science and EngineeringUniversity of WashingtonSeattle, WA 98195AbstractThere is currently great interest in using systems of FPGAs for logic emulators, custom computing devices, and software accelerators. An important step in making these technologies more generally useful is to develop completely automatic mapping tools from high-level specification to FPGA programming files. In this paper we examine one step in this automatic mapping process, the selection of FPGA pins to use for routing inter-FPGA signals. We present an algorithm that greatly increases mapping speed while also improving mapping quality. IntroductionThere is great interest in using multiple-FPGA systems for such tasks as logic emulation, software acceleration, and custom-computing devices. Many such systems are discussed elsewhere in these proceedings. An important aspect shared by all of these systems is that they harness multiple FPGAs, connected in a fixed routing structure, to perform their tasks. While the FPGAs themselves can be routed and rerouted, the wires moving signals between FPGA pins are fixed by the routing structure on the implementation board.While some very impressive results have been achieved by hand-mapping of algorithms and circuits to FPGA systems, developing a completely automatic system for mapping to these structures is important to achieving more widespread utility. In general, an automatic mapping approach will go through five phases, in the following order: Synthesis, Partitioning/Global Placement, Global Routing, FPGA Place, FPGA Route. During the Synthesis step, the circuit to be implemented is converted from its source format into a netlist appropriate for implementation in FPGAs, possibly after several optimization steps. Partitioning and Global Placement breaks this mapping into subcircuits that will fit into the individual FPGAs, and determines which FPGAs a given subcircuit will occupy. Signals that connect logic in different FPGAs are then routed during the Global Routing step, which determines both which intermediate FPGAs a signal will move through (if any), as well as what FPGA I/O pins it will use. With the logic assigned and the inter-FPGA signals routed, standard FPGA Place and Route software can then produce programming files for the individual FPGAs.Figure 1. Two views of the inter-FPGA routing problem: As a complex graph including internal resources (left), and an abstract graph with FPGAs as nodes (right).The Global Routing phase of mapping to multi-FPGA systems bears a lot of similarity to routing for individual FPGAs, and hopefully similar algorithms can be applied to both problems. Just as in single FPGAs, Global Routing needs to route signals on a fixed topology, with strictly limited resources, while trying both to handle high-density mappings and minimize clock periods. The obvious method for applying single-FPGA routing algorithms to multi-FPGA systems is to view the FPGAs as complex entities, explicitly modelling both internal routing resources and pins connected by individual external wires (figure 1 left). A standard routing algorithm would then be used to determine both which intermediate FPGA to use for long distance routing (i.e., a signal from FPGA A to D would be assigned to use either FPGA B or C), as well as which individual FPGA pins to route through. Unfortunately, this approach will not work. The problem is that although the logic has been already assigned to FPGAs during partitioning, the placement of logic intoindividual logic blocks will not be done until the next step, FPGA placement. Thus, since there is no specific source or sink for the individual routes, standard routing algorithms cannot be applied.The approach we take here is to abstract entire FPGAs into single nodes in the routing graph, with the arcs between the nodes representing bundles of wires. This solves the unassigned source and sink problem mentioned above, since while the logic hasn’t been placed into individual logic blocks, partitioning has assigned the logic to the FPGAs. It also simplifies the routing problem, since the graph is much simpler, and similar resources are grouped together (i.e. all wires connecting the same FPGAs are grouped together into a single edge in the graph). Unfortunately, the routing algorithm can no longer determine the individual FPGA pins a signal should use, since those details have been abstracted away. It is this problem, the assignment of interchip routing signals to FPGA I/O pins, that the rest of this paper addresses. Pin assignment for multi-FPGA systems One solution to the pin assignment problem is quite simple: ignore it. After Global Routing has routed signals through intermediate FPGAs, those signals are then randomly assigned to individual pins. While this simple approach can quickly generate an assignment, it gives up some optimization opportunities. A poor pin assignment can not only result in greater delay and lower logic density, but can also slow down the place and route software, which must deal with a more complex mapping problem.A second solution is to use a topology that simplifies the problem. Specifically, topologies such as bipartite graphs only connect logic-bearing FPGAs with routing-only FPGAs. In this way, the logic-bearing FPGAs can be placed initially, and it is assumed that the routing-only FPGAs can handle any possible pin assignment. More details on such an approach can be found in [1]. However, it is important to note that these approaches only apply to topologies such as bipartite graphs and partial crossbars, topologies where logic-bearing FPGAs are not directly connected.A third approach is to allow the FPGA placement tool to determine its own assignment. This requires that the placement tool allow the user to restrict the locations where an I/O pin can be assigned (e.g., Xilinx APR and PPR placement and routing tools [4]). With such a system, I/O signals are restricted to only those pin locations that are wired to the proper destinations. Once the placement tool determines the pin assignment for one FPGA, this assignment is propagated to the attached FPGAs. It is important to note that this does limit the number of placement runs that can be performed in parallel. Specifically, since the assignment from one FPGA is propagated to adjacent FPGAs only after that entire FPGA has been placed, no two adjacent FPGAs can be placed simultaneously. Since the placement and routing steps can be the most time-consuming steps in the mapping process, achieving the greatest parallelism in this task can be critical. Also, while the iterative placement approach can optimize locally, creating good results in a single FPGA, it ignores more global optimization opportunities. Finally, there are some topologies for which iterative placement may be unable to determine a correct pin assignment, because the placement of one FPGA may use up resources required in another FPGA. Force-directed pin assignment for multi-FPGA systemsAs we have discussed, pin assignment via sequential placement of individual FPGAs can be slow, cannot optimize globally, and may not work at all for some topologies. What is necessary is a more global approach which optimizes the entire mapping, while avoiding sequentializing the placement step. Intuitively, the best approach to pin assignment would be to simultaneously place all FPGAs, with the individual placement runs communicating with each other to balance the pin assignment demands of each FPGA. In this way a global optimum could be reached, and the mapping of all FPGAs would be completed as quickly as any single placement could be accomplished. Unfortunately, tools to do this do not exist, and the communication necessary to perform this task could become prohibitive. Our approach is similar to simultaneous placement, but we will perform the assignment on a single machine within a single process. Obviously, with the placement of a single FPGA consuming considerable CPU time, complete placement of all FPGAs simultaneously on a single processor is impractical, and thus simplification of the problem will be key to a workable solution.Our approach is to use force-directed placement of the individual FPGAs [3]. In force-directed placement, the signals that connect logic in a mapping are replaced by springs between the signal’s source and each sink, and the placement process consists of seeking a minimum net force placement of the logic. By finding this minimum net force configuration, we expect to minimize wirelength in the resulting mapping. To find this configuration, the software randomly chooses a logic block and moves it to its minimum net force location. This hill-climbing process continues until a local optimum is found, at which point the software accepts the current configuration.Force-directed placement may seem a poor choice for pin assignment, and is generally felt to be inferior tosimulated annealing for FPGA placement. Two reasons for this are the difficulty force-directed placement has with optimizing for goals other than wirelength, and the inaccuracy of the spring approximation to routing costs. However, force-directed placement can handle all of the optimization tasks involved in pin assignment, and the spring metric is the key to efficient handling of multi-FPGA systems.Figure 2. Example of spring simplification rules. Source circuit at top has node U replaced at middle, and any springs created in parallel to others are merged at bottom.As implied earlier, we will not simply place individual FPGAs, but will in fact use force-directed placement simultaneously on all FPGAs in the system. To make this tractable, we can simplify the mapping process. Specifically, since we are only performing pin assignment, we do not care where the individual logic blocks are placed. Thus, we can examine the system of springs built for the circuit mapping, and use the laws of physics to remove nodes corresponding to FPGA logic blocks, leaving only I/O pins. As shown in the example of figure 5, the springs connected between an internal logic node and its neighbors can be replaced with a set of springs connected between the node’s neighbors while maintaining the exact same forces on the other nodes. By repeatedly applying these simplification rules to the logic nodes in the system, we end up with a mapping consisting only of I/O pins, with spring connections that act identically to the complete mapping they replace. In this way, we simplify the problem enough to allow the pin assignment of a large system of FPGAs to be performed efficiently.We have performed comparisons of our force-directed approach with iterative placement approaches, as well as random pin assignments, on several current multi-FPGA systems. The results have shown that the force directed approach is faster than all other alternatives, including random, by up to almost a factor of ten. It also produces higher-quality results than the other approaches, yielding up to an 8.5% decrease in total wirelength in the system. Our algorithm works on arbitrary topologies, including those for which iterative placement approaches generate incorrect results. Complete results, along with a more thorough discussion of this topic, can be found in [2]. References[1] P. K. Chan, M. D. F. Schlag, "Architectural Tradeoffs in Field-Programmable-Device-Based Computing Systems", IEEE Workshop on FPGAs for Custom Computing Machines, pp. 152-161, 1993.[2] S. Hauck, G. Borriello, "Pin Assignment for Multi-FPGA Systems", University of Washington, Dept. of Computer Science & Engineering Technical Report #94-04-01, April 1994.[3] K. Shahookar, P. Mazumder, “VLSI Cell Placement Techniques”, ACM Computing Surveys, Vol. 23, No. 2, pp. 145-220, June 1991.[4] Xilinx Development System Reference Guide and The Programmable Logic Data Book, Xilinx, Inc., San Jose, CA, 1993.1 This paper is an extended abstract of University of Washington, Dept. of Computer Science & Engineering Technical Report #94-04-01, April 1994.。
预氧化技术
3 Introduction
• ClO2 oxidation prior to chlorination can reduce the levels of THM and total organic halogen (TOX) formation (Lykins and Griese,1986; Linder et al., 2006 ).
(1) the changes of NOM properties with ClO2 pretreatment.
(2) the formation of regulated and emerging DBPs from ClO2 preoxidation and in combination with chlorination or chloramination.
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• 与浊度不同,滤后水高锰酸盐指数自运行开始后一直保持稳定,说 明生物过滤对水中易氧化有机物的去除相关性不大;滤后水UV254 变化很小,说明难生物降解(shēnɡ wù jiànɡ jiě)有机物很难在生物 过滤中被去除; O3 —生物过滤对DOC 的去除率稍高。O3 和PPC 预氧化后SUVA 相对于空白试验分别降低和升高(见表1) ,而 O3 —生物过滤出水SUVA 升高较明显(见表2) ,说明O3 预氧化更 有助于生物过滤对可生物降解(shēnɡ wù jiànɡ jiě)有机物的去除。
transformed large aromatic and long aliphatic chain organic structures to small
and hydrophilic organics.
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Conclusion
基于果糖和多巴胺的碳点制备及性能
第 43 卷第 3 期2024年 5 月Vol.43 No.3May 2024中南民族大学学报（自然科学版）Journal of South-Central Minzu University（Natural Science Edition）基于果糖和多巴胺的碳点制备及性能张洋洋1，崔丽丽1，刘科2，程盈盈1，余燕敏1*（1 湖北文理学院基础医学院，湖北襄阳441053；2 湖北文理学院低维光电材料与器件湖北省重点实验室，湖北襄阳441053）摘要以果糖为碳源，多巴胺（DA）为氮源，一步水热法制备N掺杂碳点（N-CDs）.分别采用X-射线衍射仪（XRD）、高分辨透射电子显微镜（HR-TEM）、X射线光电子能谱仪（XPS）、紫外-可见吸收光谱（UV-Vis）和傅里叶变换红外光谱仪（FT-IR）等表征手段对N-CDs的结构、形貌、表面官能团及光学性质进行分析，用MTT法研究细胞毒性，用共聚焦显微技术研究细胞成像性能.结果表明：N-CDs为平均粒径约1.76 nm的球形颗粒，表面富含羟基、羧基、氨基和羰基等官能团，荧光激发和发射波长分别为440 nm和536 nm. N-CDs水溶性好，低细胞毒性，浓度为0.5 mg‧mL-1时，Hela细胞的存活率高于93%，且N-CDs易通过细胞膜进入细胞质中，在细胞内展现出较亮的荧光信号.该方法简便、绿色环保，N-CDs具有低细胞毒性，可在细胞内荧光成像，有望应用于癌细胞的早期诊断.关键词果糖；多巴胺；碳点；荧光性能；细胞成像中图分类号O657.3 文献标志码 A 文章编号1672-4321（2024）03-0319-07doi：10.20056/ki.ZNMDZK.20240304Preparation and properties of carbon dots based on fructose and dopamine ZHANG Yangyang1，CUI Lili1，LIU Ke2，CHENG Yingying1，YU Yanmin1*（1 School of Basic Medicine， Hubei University of Arts and Science， Xiangyang 441053，Hubei， China；2 Hubei Key Laboratory of Low Dimensional Optoelectronic Materials and Devices， Hubei University ofArts and Science， Xiangyang 441053，Hubei China）Abstract Nitrogen doped carbon dots （N-CDs）were synthesized via one-step hydrothermal method using fructose as carbon source and dopamine （DA） as nitrogen source. The structure， morphology， surface functional groups and optical properties of N-CDs were characterized via X-ray diffraction （XRD），high-resolution transmission electron microscopy （HRTEM），X-ray photoelectron spectrometer （XPS），ultraviolet-visible absorption spectrum （UV-vis），Fourier-transform infrared spectroscopy （FT-IR）and other characterization techniques. The cytotoxicity was studied by MTT assay，and cell imaging performance was studied by confocal microscopy. The results showed that the N-CDs were spherical particles with an average particle size of about 1.76 nm. The surface was rich in functional groups，such as hydroxyl， amino， carboxyl and carbonyl groups. The fluorescence excitation and emission wavelengths of the N-CDs were 440 nm and 536 nm， respectively. The N-CDs demonstrated good water solubility and low cytotoxicity. At a concentration of 0.5 mg∙mL-1， the survival rate of Hela cells was higher than 93%. N-CDs could easily enter the cytoplasm through the cell membrane and showed bright fluorescence signal in the cell. This method is simple，green and environmentally friendly. The N-CDs have low cytotoxicity and can be used in intracellular fluorescence imaging， which is highly desirable for the early diagnosis of cancer cells.Keywords fructose； dopamine； carbon dots； fluorescence properties； cell imaging收稿日期2023-04-01* 通信作者余燕敏（1985-），女，副教授，博士，研究方向：功能纳米材料的设计合成及其应用，E-mail：yuyanmin2005@ 基金项目国家自然科学基金资助项目（51809087）；中国国家留学基金资助项目（202008420051）；湖北省教育厅科学技术研究资助项目（Q20182601）第 43 卷中南民族大学学报（自然科学版）碳点（carbon dots，CDs）是一种新型发光碳纳米材料，主要由C、H、O元素构成，与传统半导体量子点相比，CDs具有水溶性好、荧光性能强、生物相容性好、低毒性、低成本、易制备、易功能化等优点［1-3］，已在化学传感［4］、生物医学［5-6］、离子检测［7-8］和催化学［9-10］等领域展现极好的应用前景.高效、灵敏地监测单个细胞的生命活动进程，将对阐明细胞生理过程产生极大的促进作用.CDs作为细胞生命动态过程及动物活体内肿瘤的靶向荧光示踪剂，因其高灵敏度、低毒性、良好的时空分辨率、操作简单和无创实时等优点成为监测细胞生命活动进程的首选方法［11-13］.目前，CDs制备方法主要有水热法［14-15］、热解法［16-17］、微波辅助法［18］、激光消融法［19］等，其中水热合成法，因其操作简单，绿色经济等优点，成为合成CDs 的主要方法［20］.本文采用简易的水热法，以含有多羟基D-果糖为碳源，含酚羟基和氨基的多巴胺为氮源，一锅水热合成N-CDs.合成的N-CDs为尺寸均匀的球形纳米颗粒，平均粒径约为1.76 nm，表面含羟基、羧基、氨基和羰基等官能团，具有良好的水溶性和生物相容性，荧光特性优异.N-CDs具有低细胞毒性，易通过细胞膜进入细胞质中，在细胞内展现出较亮的荧光信号.本合成方法操作简单、绿色环保，制备的N-CDs发光性能稳定，细胞毒性低，在细胞成像尤其是肿瘤细胞成像中具有潜在的应用价值. 1 实验部分1.1 试剂和仪器果糖（国药集团化学有限公司）；多巴胺（上海源叶生物科技有限公司）；超纯水采用Millipore系统的二次水；Hela细胞（普诺赛公司）；DMEM/High Glucose、磷酸盐缓冲液（PBS）、MTT、DMSO、10%胎牛血清购自武汉塞维尔生物科技有限公司.所用试剂均为分析纯.傅立叶变换红外光谱仪（FT-IR，Nicolet IS 5）；X 射线衍射仪（XRD，Rigaku Ultima IV）；场发射透射电镜（TEM，JEOL JEM-2100 F）；X射线光电子能谱（XPS，Thermo Fisher Scientific K-Alpha Plus）；荧光光谱仪（Hitach F-4600）；多功能荧光酶标仪（Molecular Devices SpectraMax i3x）；电子分析天平（Mettler Toledo AL104）；电热鼓风干燥箱（上海博迅实业有限公司医疗设备厂，GZX-9030MBE）；荧光共聚焦显微镜（Leica TCS SP8）.1.2 实验方法1.2.1 N-CDs的制备称取2.0 g果糖和0.02 g多巴胺，溶于15 mL的去离子水，搅拌5 min后，转移至50 mL的聚四氟乙烯里衬水热反应釜中，于电热恒温鼓风干燥箱180 ℃下加热24 h，反应结束后自然冷却至室温.将所得溶液在4500 r·min-1转速下离心5 min，6次后用0.22 µm 的微孔滤膜过滤得到黄色滤液，即N-CDs溶液，置于4 ℃冰箱保存备用.采用同样方法不添加DA制备CDs，不添加果糖制备DA参照溶液.1.2.2 细胞毒性采用MTT法检测N-CDs的细胞毒性.Hela细胞以每孔8×103个细胞接种于96孔板，每孔体积为100 µL.将96孔板置于细胞培养箱（5% CO2，37 ℃）培育24 h，然后加入不同浓度的碳点100 µL继续培养24 h后，用PBS清洗3遍，每孔加入含有MTT的新鲜培养基100 µL，放入细胞培养箱继续培养4 h.吸弃上清液，每孔加100 µL DMSO，轻微震荡.酶标仪测量每孔在490 nm波长处的吸光度值，记录并处理实验结果.以未处理细胞的吸光度值为100%，计算在不同浓度的N-CDs，细胞的存活率.1.2.3 细胞成像将对数生长期Hela细胞按照每孔1×104个分散于装有载玻片的六孔板中，于细胞培养箱37 ℃下培养24 h.细胞贴片后，加入制备的N-CDs继续孵育6 h.取出载玻片，用PBS溶液把细胞洗涤3遍.细胞固定之后，用共聚焦显微成像技术观察细胞的成像情况.2 结果与讨论2.1 碳点合成条件优化运用单因素法对制备N-CDs的条件（反应温度、反应时间、果糖用量和果糖-DA用量比）进行优化，以制备光学性能优异的N-CDs.实验结果表明最佳合成条件为：反应温度180 ℃、反应时间24 h，果糖用量2.0 g，DA用量为0.02 g.考察水热反应温度和反应时间对CDs荧光强度的影响，结果见图1.由图1（a）可知：反应时间24 h时，制备的CDs荧光性能最强；由图1（b）可知：反应温度180 ℃时，CDs荧光性能最强.故本研究选择反应时间24 h、反应温度180 ℃.320第 3 期张洋洋，等：基于果糖和多巴胺的碳点制备及性能2.2 CDs 和N -CDs 表征和性质不同果糖用量制备的CDs 的TEM 结果见图2（a ）‒2（f ）.由图可知：用果糖制备的碳点均呈球形结构，水溶性好，分散性良好.果糖用量为0.5、1.0、1.5、2.0、2.5、3.0 g 时，合成的CDs 平均粒径分别为4.06、4.10、2.56、1.70、2.50、3.05 nm ，表明果糖用量影响碳点的粒径.当果糖的量大于2.0 g 后，CDs 球形颗粒出现团聚现象；用量3.0 g 时，团聚明显.添加氮源DA 后，制备的N -CDs 的TEM 结果见图2（g ）、2（h ）.由图可知：DA 的加入量0.2 g 时，N -CDs 平均粒径约为3.9 nm ；DA 用量0.02 g 时，制备的N -CDs 平均粒径约为1.76 nm.图3为CDs 和N -CDs 的XRD 图.图中CDs 和N -CDs 均在2θ为19˚~23˚处有一个较宽的衍射峰，该衍射峰归属为石墨结构的（002）面［21-22］.由谢乐公式可知：半峰宽越大，粒径越小；如表1所示：果糖用量为2.0 g 时，半缝宽最宽，粒径较其他用量小，与TEM 结果相符.N -CDs 的XRD 图谱在2θ为22.58˚处均有一个宽的衍射峰，与CDs 相比，衍射峰的半缝宽较CDs 变窄，粒径较CDs 增大，表明DA 的加入对CDs 晶型的影响较小.图4为CDs 和N -CDs 的FT -IR 图.图4（a ）为不同果糖用量1.0、1.5、2.0、2.5 g 制备的CDs 的FT -IR 图，由图可知：不同果糖用量制备的CDs 的红外特征吸收峰一致，说明果糖用量不影响CDs 的官能团组成.3373 cm -1馒头式吸收峰为―OH 的伸缩振动峰；1707、1309、1205 cm -1吸收峰分别归属为C =O 的伸缩振动峰，C ―H 弯曲振动峰和C ―O 伸缩振动峰［23-24］；1452 cm -1和871 cm -1的O ―H 的变形震动峰［25］说明果糖为碳源制备的CDs 含有羟基、羧基和羰基等官能团，CDs 良好的水溶性与这些基团相关［23-27］.图4（b ）中，DA 为前驱物制备的DA 溶液的红外谱图中1638 cm -1强吸收峰，归属于DA 苯环中的C =C 的伸缩振动峰.在N -CDs 的红外特征吸收峰中，与CDs 的50055060065070002004006008001000120014001600 16 h 20 h 24 h 28 hF L i n t e n s i t y2004006008001000120014001600F L i n t e n s i t yλ/nm (a) 反应时间500550600650700λ/nm (b) 反应温度220 ℃200 ℃180 ℃160 ℃图1 CDs 荧光性能Fig.1 Fluorescence spectra of CDs(a) 0.5 g(b) 1.0 g(c) 1.5 g(d) 2.0 g(h) 0.2 g fructose-0.02 g DA(g) 2.0 g fructose-0.2 g DA(f) 3.0 g(e) 2.5 g345Diameter/nm1230102030Diameter/nm2435Diameter/nm2435Diameter/nm1324Diameter/nmF r e q u e n c y /%346505Diameter/nm2354Diameter/nm1243Diameter/nmF r e q u e n c y /%510152025F r e q u e n c y /%5F r e q u e n c y /%F r e q u e n c y /%0F r e q u e n c y /%F r e q u e n c y /%F r e q u e n c y /%图2 不同果糖用量制备的CDs （a -f ）和N -CDs （g -h ）的TEM 图Fig.2 TEM images of CDs （a -f ） and N -CDs （g -h ） prepared with different amounts of fructose321第 43 卷中南民族大学学报（自然科学版）特征吸收峰相比，3373 cm -1馒头式吸收峰变宽，为―OH 和―NH 的伸缩振动峰，C =O 的伸缩振动峰发生了改变，由1707 cm -1改变至1671 cm -1，且在1081 cm -1呈现C ―N 吸收峰，在1522 cm -1呈现N ―H 的特征峰，说明N 元素成功掺入CDs 形成N -CDs ，结构中含有羟基、羧基、氨基和羰基等官能团［27］.XPS 研究CDs 和N -CDs 的元素组成和元素化合价态，如图5所示.图5（a ）可知，XPS 全谱图中有2个明显的峰，对应结合能为284.6 eV 和532.7 eV ，归属为C 1s 和O 1s ，说明CDs 主要含C 和O 两种元素，与CDs 相比，N -CDs 的XPS 全谱图中新出现了400.0 eV 吸收峰，归属为N 1s ，说明DA 的加入，成功将N 元素掺杂入CDs.由图5（b ）中的O 1s 高分辨扫描XPS 谱图，对其去卷积分峰拟合，CDs 在531.5 eV 和533 eV 处有2个峰，分别归属为C =O 和C ―O （H ），N -CDs 在531.5、532.3、533.3 eV 处有3个峰，分别归属为C =O 、C ―O ―C 和C ―O （H ） ［22］.图5（c ）的C 1s 高分辨XPS 谱图分峰拟合结果显示：CDs 在284.78、286.48、288.53 eV 处有3个峰，分别归属为C ―C 、C ―O 和C =O 基团.N -CDs 在284.58、285.38、286.53、288.63 eV 处有4个峰，分别归属为C ―C 、C ―N 、C ―O 和C =O 基团［22］.图5（d ）是N 1s 的高分辨XPS 谱图分峰拟合，图中结合能399.7、401.5 eV 分别归属C ―N ―C 键和H ―N键，表明合成的N -CDs 含有羟基、羧基、氨基和羰基等官能团，与FT -IR 结果一致.XPS 价带谱包含元素的化学信息和电子结构信息，且线形与价电子结构有密切的关系［28］.由图5（e ）可见：CDs 与N -CDs 的价带谱上均有3个基本峰，与石墨碳价带谱近似，说明合成碳点有石墨烯结构特征［29］，与XRD 结论一致.图6为DA 、CDs 和N -CDs 的紫外-可见吸收光谱、激发/发射光谱.由图6（a ）‒（c ）中，DA 主要吸收峰位于227 nm 处，CDs 的主要吸收峰位于296 nm 处，N -CDs 的紫外光谱图中存在227 nm 和296 nm 两处吸收峰，分别对应于π-π*、n -π*跃迁［30-31］.荧光光谱图6（d ）‒（f ）为DA 、CDs 和N -CDs 在不同激发波长（380 nm~460 nm ，间隔10 nm ）扫描下的荧光光谱图，由图可知，DA 、CDs 和N -CDs 的最大发射波长分别位于475、540、536 nm.当激发波长由380 nm 增加到460 nm 时，荧光强度先增大后减小，荧光发射峰发生红移，位置与强度对激发波长具有较强的依赖性，主要由1020304050607080CDs-1N-CDs CDs-2CDs-3CDs CDs-4CDs-52θ/(°)图3 CDs 、N -CDs 的XRD 图Fig.3 XRD pattern of the CDs and N -CDs表1 不同果糖用量制备碳点的XRD 衍射峰参数Tab.1 XRD diffraction peak parameters of quantum dots preparedwith different amount of fructose样品CDs -1CDs -2CDs -3CDsCDs -4CDs -5N -CDs 果糖用量/g0.51.01.52.02.53.02.0半缝宽/（˚）17.1216.8721.3822.1917.9618.4220.312θ/（˚）19.4219.7020.4820.4820.0620.8222.5820406080100σ/cm -1σ/cm -1(τ)λ/%20406080100(τ)λ/%图4 CDs 和N -CDs 的傅里叶变换红外光谱Fig.4 FT -IR spectra of CDs and N -CDs322第 3 期张洋洋，等：基于果糖和多巴胺的碳点制备及性能于碳点表面的缺陷作为激发能阱和粒子粒径对光的选择性不同所致［30］，此现象属于石墨碳点的典型特征［25，30］.采用不同浓度（0~1.0 mol ‧L -1）NaCl 溶液中N -CDs荧光光谱的方法研究N -CDs 离子稳定性，N -CDs 具有良好的离子稳定性，当浓度为1 mol ‧L -1时，荧光强度减弱仅11%.氙灯持续照射N -CDs 溶液，研究光稳定性，实验结果表明：N -CDs 溶液荧光强度随着氙灯的不断照射呈现出非常微小的下降趋势，其氙灯照射100 min 后的荧光强度仍有最初强度的92%，表530531532533534535N-CDsO 1sC—O—CC—O (H)CDsC =OC—O (H)C =O282284286288290CDsC—C C—NC—OC =O N-CDsC 1sC—CC =O C—O396398400402404N 1sN-CDsC—N—CN—HCDsN-CDs24681020040060080010001200(a) 全谱CDsN-CDsC 1sN 1sO 1s E b /eV (d) N 1sE b /eV (e) 价带谱E b /eV (b) O 1sE b /eV (c) C 1sE b /eV 图5 CDs 和N -CDs 的XPS 谱图Fig.5 XPS spectra of the CDs and N -CDs4505005506006507001 380 nm2 390 nm3 400 nm4 410 nm5 420 nm6 430 nm7 440 nm8 450 nm 9460 nmF L i n t e n s i t y1234567894505005506006507001 380 nm 2 390 nm 3 400 nm 4 410 nm 5 420 nm 6 430 nm 7 440 nm 8 450 nm 9460 nmF L i n t e n s i t y1234567894004505005506006501 380 nm 2 390 nm 3 400 nm 4 410 nm 5 420 nm 6 430 nm 7 440 nm 8 450 nm 9460 nmF L i n t e n s i t y123456789200300400500600700800A b s o r b a n c eEmExAbsF L i n t e n s i t y200300400500600700800A b s o r b a n c eEmEx AbsF L i n t e n s i t y200300400500600700800A b s o r b a n c eλ/nm (a) DAλ/nm (d) DAλ/nm (b) CDsλ/nm (e) CDsλ/nm (c) N-CDsλ/nm (f) N-CDsF L i n t e n s i t yAbsExEm图6 紫外-可见吸收光谱、荧光激发、荧光发射光谱和不同激发波长下的荧光光谱Fig.6 UV -vis absorption ， fluorescence excitation and fluorescence emission spectra and fluorescence spectra of CDs at the various excitation wavelengths323第 43 卷中南民族大学学报（自然科学版）明N -CDs 光稳定性良好.2.3 碳点生物成像性能2.3.1 细胞毒性采用MTT 法测定CDs 与N -CDs 对Hela 细胞的体外细胞毒性，结果如图7所示.由图7可知：在CDs 和N -CDs 浓度为0.5 mg ‧mL -1条件下，Hela 细胞的存活率分别为85%和93%，当浓度高达1.0 mg ‧mL -1条件时，Hela 细胞的存活率有所下降，存活率可达70%和84%.MTT 实验表明，CDs 和N -CDs 具有较低的细胞毒性.2.3.2 细胞成像将合成的N -CDs 与Hela 细胞共培养6 h ，在激发波长405 nm 条件下，Hela 细胞的荧光共聚焦显微结果见图8.由图8可知：细胞孵育情况良好，N -CDs 标记的Hela 细胞在405 nm 激发下，可发出较亮的绿光，表明N -CDs 通过细胞膜进入Hela 细胞中.细胞成像的结果说明，N -CDs 具有良好的生物相容性，在细胞中保持良好的荧光性能，且N 元素掺杂，修饰的CDs 提高其在细胞成像中的荧光强度，表明N -CDs 有望运用在Hela 细胞的靶向识别和成像.3 结语本文采用水热法一步合成了生物相容性好、水溶性好、粒径均一的氮掺杂-碳点复合材料（N -CDs ），合成过程原料简单易得，操作简便.原料果糖用量对量子点粒径影响明显，果糖用量为2.0 g 时，多巴胺为0.02 g 时，制得碳点呈球形，分散性好，粒径约1.76 nm.多巴胺为氮源，由于多巴胺分子间力，N -CDs 分散性明显增大.通过N -CDs 与Hela 细胞共培养可知N -CDs 具有低细胞毒性，在恶性肿瘤细胞中能发出较强的荧光，说明碳点对恶性肿瘤细胞具有识别作用，在癌症的早期诊断中具有优异的潜在的应用价值.参 考 文 献［1］ JOHN J ， MATHEW R M ， THOMAS T ， et al. 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Highly luminescent S ，N Co -doped graphene quantum dots with broad visible20406080100ρ/(mg·ml -1)C e l l v i a b i l i t y /%图7 CDs 和N -CDs 培养48 h 后的细胞毒性Fig.7 Cytotoxicity after culturing Hera cells using CDs and N -CDs for 48 h图8 Hela 细胞的共聚焦荧光图像Fig.8 Confocal fluorescence images of Hela cells324第 3 期张洋洋，等：基于果糖和多巴胺的碳点制备及性能absorption bands for visible light photocatalysts［J］.Nanoscale， 2013， 5（24）： 12272-12277.［11］YU C，QIN D，JIANG X，et al. Facile synthesis of bright yellow fluorescent nitrogen-doped carbon quantumdots and their applications to an off‒on probe for highlysensitive detection of methimazole［J］. MicrochemicalJournal， 2021， 168： 106480.［12］LI Z，WANG Q，ZHOU Z，et al. Green synthesis of carbon quantum dots from corn stalk shell by hydrothermalapproach in near-critical water and applications in detectingand bioimaging ［J］. Microchemical Journal， 2021， 166（13）： 106250.［13］LIU L，MI Z，HUO X，et al. A label-free fluorescence nanosensor based on nitrogen and phosphorus co-dopedcarbon quantum dots for ultra-sensitive detection of newcoccine in food samples［J］. Food Chemistry，2022，368： 130829.［14］GAO S，WANG X，XU N，et al. From coconut petiole residues to fluorescent carbon dots via a green hydrothermalmethod for Fe3+ detection［J］. Cellulose， 2021， 28（3）：1647-1661.［15］WANG Y，LIU Y，ZHOU J，et al. Hydrothermal synthesis of nitrogen-doped carbon quantum dots fromlignin for formaldehyde determination［J］. RSCAdvances， 2021， 11（47）： 29178-29185.［16］李志英，李洋. 红枣碳量子点荧光探针的制备及对食品中赖氨酸的检测［J］. 化学研究与应用，2018，30（11）： 1902-1907.［17］EL-MALLA S F， ELSHENAWY E A， HAMMAD S F，et al. N-doped carbon dots as a fluorescent nanosensor fordetermination of colchicine based on inner filter effect［J］.Journal of Fluorescence， 2021， 31（3）： 675-684.［18］ARCHITHA N， RAGUPATHI M， SHOBANA C， et al.Microwave-assisted green synthesis of fluorescent carbonquantum dots from Mexican Mint extract for Fe3+ detectionand bio-imaging applications［J］. EnvironmentalResearch， 2021， 199： 111263.［19］SIDOROV A I，LEBEDEV V F，KOBRANOVA A A，et al. Formation of carbon quantum dots and nanodiamondsin laser ablation of a carbon film［J］. QuantumElectronics， 2018， 48（1）： 45-48.［20］SINGH V， RAWAT K S， MISHRA S， et al. Biocompatiblefluorescent carbon quantum dots prepared from beetrootextract for in vivo live imaging in C. elegans and BALB/cmice［J］. Journal of Materials Chemistry B，2018，6（20）： 3366-3371.［21］LI H T，HE X D，KANG Z H，et al. Water-soluble fluorescent carbon quantum dots and photocatalystdesign［J］. Angewandte Chemie （International Ed inEnglish）， 2010， 49（26）： 4430-4434.［22］LIU Y，ZHOU L，LI Y，et al. Highly fluorescent nitrogen-doped carbon dots with excellent thermal andphoto stability applied as invisible ink for loading importantinformation and anti-counterfeiting［J］. Nanoscale，2017，9（2）： 491-496.［23］HSU P C， CHANG H T. Synthesis of high-quality carbon nanodots from hydrophilic compounds：Role of functionalgroups［J］. Chemical Communications， 2012， 48（33）：3984-3986.［24］MEHTA V N， JHA S， SINGHAL R K， et al. Preparation of multicolor emitting carbon dots for HeLa cell imaging［J］.New Journal of Chemistry， 2014， 38（12）： 6152-6160.［25］张现峰，芦静波，王学梅. 温敏性碳量子点的快速制备、荧光性质及细胞成像应用［J］. 分析测试学报，2018， 37（2）： 198-203.［26］LIU G，WANG X，HAN G，et al. Earth abundant colloidal carbon quantum dots for luminescent solarconcentrators［J］. Materials Advances，2020，1（2）：119-138.［27］胡国文，乔玉玲. 叶酸修饰的碳量子点在体外癌细胞成像中的应用［J］. 应用化学， 2020， 37（9）： 1003-1009.［28］朱永法，郑斌，姚文清，等. 电子能谱线形分析研究碳物种的化学状态［J］. 分析化学， 1999， 27（1）： 10-13.［29］BAKER S N， BAKER G A. Luminescent carbon nanodots：Emergent nanolights［J］. Angewandte Chemie（International Ed in English），2010，49（38）：6726-6744.［30］杨彩玲，赵国虎，张鸣，等.氮掺杂碳量子点荧光猝灭法测定柠檬黄［J］. 化学研究与应用， 2019， 31（7）：1293-1298.［31］黄湘，周莉佳，粟小燕，等. 基于甘草酸的荧光纳米碳点的合成及性能研究［J］. 化学试剂， 2022， 44（8）：1142-1147.（责编&校对刘钊）325。
晶体自范性和自生成模板法结合生长组装多级纳米结构_谢毅
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中国科学技术大学学报
第 38 卷
acted as the suppo rt fo r the co nst ruction of rutile TiO 2 3D hollow nanostructures . F urthermo re , VOOH hollo w “ dandelions” w ere sy nthesized owi ng t o the planar sheet nature of the bui lding blo cks in the newphased VOOH and the in-si tu produced N 2 gas bubbles as t he templates t hat acted as the sheet-like nanouni t ssupport er . Also , tit anat e 3D t ubular hierarchit ect ures w ere successfully prepared undergoing t he self-produced template methodolog y coupled w it h precurso r tem plat ing approach based on the similar st rategy . T he appearance of tit anat e nanof lakes i s actually the o ut w ard em bodiment o f the internal crystal st ructure , w hile the sacri ficed t em plat ing ef fect of the int ermediate precurso r of T iO x Cl2 -2x ( EN ) y is w ell underst ood . Key words : crystal g ro w th ; self-limi tatio n prope rty ;self-produced t emplate st rategy ; t hree-dimensi onal hie ra rchi tectures ; cry st al st ruct ure
荧光定量PCR
聚合酶链式反应( PCR) 可对特定核苷酸片断进行指数级的扩增。
在扩增反应结束之后，我们可以通过凝胶电泳的方法对扩增产物进行定性的分析，也可以通过放射性核素掺入标记后的光密度扫描来进行定量的分析。
无论定性还是定量分析，分析的都是PCR 终产物。
但是在许多情况下，我们所感兴趣的是未经PCR 信号放大之前的起始模板量。
例如我们想知道某一转基因动植物转基因的拷贝数或者某一特定基因在特定组织中的表达量。
在这种需求下荧光定量PCR 技术应运而生。
实时定量PCR技术，是指在PCR反应体系中加入荧光基团，利用荧光信号积累实时监测整个PCR进程，使每一个循环变得“可见”，最后通过Ct值和标准曲线对样品中的DNA (or cDNA) 的起始浓度进行定量的方法。
实时荧光定量PCR是目前确定样品中DNA (或cDNA) 拷贝数最敏感、最准确的方法。
Real-Time PCR and Conventional PCR常规PCR ProcessIn theory, product accumulation is proportional to 2n, where n is the number of amplification cycle repeatsReality vs. Theory Amplification is exponential, but the exponential increase is limited:-A linear increase follows exponential-Eventually plateaus常规PCR方法的局限性分析：-无法对起始模板准确定量,只能对终产物进行分析-必须在扩增后用电泳方法分析,费时费力而且EB有毒-无法对扩增反应实时检测定量的最佳时期Quantitative information comes from monitoringthe early stages of amplification荧光定量PCR和常规PCR技术的区别常规PCR是通过电泳对扩增反应的最终产物进行定性分析（定量不准确）；荧光定量PCR是在PCR反应体系中加入荧光基团，利用荧光信号积累实时监测整个PCR进程，使每一个循环变得“可见”，通过Ct值和标准曲线对样品中的DNA (or cDNA) 的起始浓度进行定量的方法（准确定量）。
Dept.ofComputerScience
Introduction
of the problem) can be reduced to the same problem for a di erent, normally smaller instance, called the kernel of the program. Second. the same works propose a novel graph representation of logic programs, called Extended Dependency Graphs (EDG), which allowed us to characterize stable models of a program in terms of distinguished 2-colorings of its EDG. These colorings are called admissible. In other words, there is a one-to-one correspondence between the answer sets of a kernel program Ker( ) and admissible 2-colorings of the related Extended Dependency Graph EDG(Ker( )). Therefore, the ASP problem is rephrased in terms of nding particular colorings of directed graphs; this problem will be called Admissible Coloring Problem (ACP). Since the ASP problem is NP-complete, so is ACP, hence exact solutions to ACP cannot be found in polynomial time (of course, in the worst case). Our approach, described in the rest of the paper, is to relax the problem to that of optimizing a suitable objective function (called tness from now on). More precisely, we try to solve ACP by means of a continuous model of computation. We propose: 1. to relax ACP to combinatorial optimization problem, by associating each instance of the problem to a suitable tness function, so that admissible colorings are exactly global maxima of every tness function, 2. to maximize a tness function by using the genetic model proposed in (Bertoni et al., 2000). In this model, the tness function corresponds to a discretetime system whose attractors are local maxima of the tness function itself. In this Section we show a reduction from ASP computation to a particular type of graph coloring introduced in (Brignoli et al., 1999). The rst step consists in reducing the original program to a new, smaller program Ker( ) which is equivalent to the original as far as existence and number of answer sets are concerned.
LUNARPRODIGY
GE HealthcareGE imagination at workLunar ProdigyDirect-Digital DensitometryProdigy.A breakthrough in fracture risk assessment.At GE Healthcare, we’re firmly committed tofinding new and more effective ways to helpphysicians diagnose osteoporosis and assessfracture risk.That’s why we developed the innovativeProdigy – the first system designed to lookbeyond bone mineral density to become themost complete bone assessment tool everdevised. Prodigy’s improved technologydetects subtle bone changes in a variety ofclinical conditions and provides Advanced HipAnalysis and Lateral Vertebral Assessment.Utilizing Direct-digital detector technology,Prodigy delivers rapid scans, near radio graphicimaging and dose efficiency three to five timesbetter than existing fan beam systems. And itscomprehensive capabilities cover a completerange of applications.Prodigy’s unique software platform, enCORE™,optimizes productivity with automation break-throughs that save time and ensure consistentresults. And paperless digital reporting makesdensitometry results accessible quickly andeasily.Looking ahead, Prodigy links you to the futurewith extensive options for connecting withlocal facility networks and the Internet, forinstant integration of bone assessment resultsacross your entire healthcare system.The precise depth and location of bone canvary significantly from patient to patient,depending on patient age, size and shape.The wide-angle design used by competitivefan beam systems is subject to distortioncaused by magnification. This makes itdifficult to determine the true bone areaand geometry with any degree of accuracy.With these technological limitations,competitive systems can only estimate themineral content, geometry and size of bonebased on an approximation of its depth.Prodigy’s unique technology eliminates all ofthis guesswork. Its narrow-angle fan beammakes multiple passes across the patient toacquire multiple images, with each imageoverlapping the previous one.Then, Multi-View Image Reconstruction – animaging technique perfected in computedtomography, or CT – slides these overlappingimages together for a perfect match.The result: the exact depth of the bone isdetermined accurately in every patient,ensuring precise, reliable, consistentmeasurement of area, bone mineral contentand geometry such as hip axis length (HAL).“HAL has been demonstrated in several prospectivestudies to predict fractures. Each centimeter (10%)increase in HAL increases hip fracture risk by 50-80%,depending on the study. Precision error of HAL on theProdigy, determined from 43 subjects scanned multi-ple times, was 0.7%. While HAL cannot be viewed asa stand-alone clinical predictor, it can potentially pro-vide utility in conjunction with BMD to identify high-risk patients.”Kenneth G. Faulkner, Ph.D.Chief ScientistGE HealthcareComplete accuracyfrom any angle.WIDE-ANGLE FAN BEAM NARROW-ANGLE FAN BEAMSINGLE SWEEPMULTI-VIEWBy reconstructing multiple images acquired by multiplepasses of its narrow-angle fan beam, Prodigydetermines the exact location, and the precise size andshape, of the spine and hip to accurately determinebone area, bone mineral content and bone geometry,such as hip axis length.Wide-angle fan beam designs used by competitivesystems don’t correct for magnification. Differencesin bone depth across patients, or even changes inpositioning of the same patient, are projected asdifferent sizes on the detector, making it difficult toaccurately measure hip axis length.Prodigy’s narrow-angle fan beam reducesdistortion due to magnification. The multi-view imagereconstruction algorithm discerns the bone’s truedepth, for accurate determination of bone mineralcontent, size and geometry.Expanded clinical utility .Right down to the bone.Evidence continues to mount that there isadditional clinical information to be derivedfrom femoral bone density measurements –if the necessary analysis software wereavailable.Now, for the first time ever, the GE LunarProdigy delivers these remarkableanalytical capabilities. Advanced Hip AnalysisThe Prodigy provides the first majoradvances in femoral densitometry analysissince the introduction of DXA system soft-ware in 1987. These advances are includedin the new Advanced Hip Analysis software,available exclusively on the Prodigy.Advanced Hip Analysis includes all thestandard femoral regions of interest thathave been previously available, but nowincludes the addition of other key measure-ments and assessments:• Hip Axis Length (HAL) has been demon-strated in prospective studies as aneffective adjunct to femur bone densityin predicting fracture risk.• DualFemur ™Assessment identifies theweakest femur while improving precisionover single-femur measurements.• New diagnostic regions of interest such asthe upper neck can now be accuratelyassessed.• Femur Strength Index : A unique Indexcombining geometrical parameters andBMD for a better assessment.“Advanced Hip Analysis combines several advances in DXA measurement of the proximal femur into a single software package. It maintains the conventional femoral regions of interest, but with a precision previously only obtained at the spine. This feature alone represents a significant advance in femoral densitometry.”Kenneth G. Faulkner, Ph.D.Chief Scientist GE HealthcareDual femur assessmentSingle Femur Dual Femur Precision Precision Total Femur Region 1.0% CV 0.6% CVLateral Vertebral Assessment-quantifiedProdigy’s Lateral Vertebral Assessment-quantified (LVAq) improves fracture riskassessment by identifying and quantifyingexisting vertebral fractures – which at leastdouble future fracture risk regardless of apatient’s bone density.LVAq subtracts soft-tissue artifacts forbetter bone images and easier visualassessment. In addition, reference data isprovided for vertebral height and A/P ratio,and the Morphometry Wizard feature allowsfor easy step-by-step quantification.Total Body AssessmentThe ultimate in skeletal assessment, theTotal Body exam provides both bone densityand body compositon (i.e., % fat) results.With an FDA-approved, gender-matcheddatabase, total body results expand theutility beyond osteoporosis managementwhere the combined results are used in avariety of secondary conditions, or whenspine/hip measurements are compromised.Orthopedic AnalysisThe enCORE software platform facilitatesaccurate, customized analysis. Hipprostheses, metal fastenings and otherartifacts are easily excluded from theanalysis region for accurate bone densityresults. Customized regions of interest ofany shape and size can be quickly definedfor greater utilization, and customizedenCORE analysis assures precise resultswhile expanding your clinical and researchteral Vertebral Assessment-quantifiedTotal Body AssessmentOrthopedic AnalysisOneVision reporting automatically generatesa single, concise clinical report for all scansperformed during a patient's visit. Standardtext can be customized with patient-specificcomments and changes to save time andeliminate transcription costs.Loaded with features for faster, easier and more convenientoperation, the Prodigy will streamline performance and throughput in the busiest practices, clinics and departments.Revolutionary enCORE software optimizes productivity.Based on Windows XP ® Professional, GE Lunar’s unique enCOREsoftware provides true Windows capabilities, including right-clickmenus, drag-and-drop editing and integration with other applica-tions. Multiple scans can also be opened simultaneously. enCORE’s intuitive graphical interface provides ease-of-use, fast throughput and automation that frees the operator for other tasks.One-step AutoAnalysis delivers fast, precise, consistent results.Excellent precision, or reproducibility, is key to detecting smallchanges in bone density. enCORE’s AutoAnalysis calculates results in just one keystroke, for fast, precise analysis. Only GE Lunaroffers true one-button analysis, eliminating operator variability,subjective decisions and inconsistent analysis in over 90% of scans.OneVision scanning and reporting saves time and costs.The Prodigy automatically combines scans of the spine and bothhips into one comprehensive exam, acquired in one process andevaluated in one analysis. Rather than receiving multipleassessment reports, the referring physician receives a single,consolidated report that combines all risk assessment analysesfor greater convenience and time savings.No speed limit.MeasureAnalyzeA state-of-the-art fracture risk assessment tool, Prodigy will serve your needs exceptionally well today – and continue serving those needs just as effectively far into the future.Digital connectivity and network integration provide fast, widespread communications. Utilizing Prodigy’s enCORE software, bone density results can be digitally transmitted throughout your healthcare enterprise – or anywhere in the world via the Internet – for viewing on remote workstations.Exclusive DICOM and HL7 compatibility ensures maximum connectivity.A Prodigy exclusive, DICOM seamlessly integrates densitometry results with Radiology Information Systems (RIS) and Picture Archival and Communication Systems (PACS). Digital densitometry results may then be viewed on remote DICOM review stations. With Worklist, patient information can also be received directly from scheduling applications via HL7 or DICOM for faster throughput and reduced data entry errors.TeleDensitometry™speeds reports toreading or referring physicians.With TeleDensitometry, digital paperless reports are sent as faxes or as simple attachments to standard email messages that can be viewedon any personal computer without the need for special software. The digital report contains all the information found in the standard hard-copy report, including patient information, high-resolution images, a reference graph, a clinical results table and a trending graph to monitor changes over time.GE Continuum protects your investment.To keep your bone densitometry and assessment capabilities current through rapid advances in technology, new features and applications can be easily added to your Prodigy as economical software upgrades, ensuring you of state-of-the-art system perfor-mance for years to come.A platform for productivity. Today and tomorrow.Comprehensive Clinical Capabilities• Advanced Hip Analysis• Lateral Vertebral Assessment-quantified • Total Body Assessment• AP Spine• Forearm• Orthopedic Analysis• Ultra Low-Dose PediatricsFor more than 100 years, healthcare providers worldwide have relied on GE Healthcare for medical technology,services and productivity solutions.So no matter what challenges yourhealthcare system faces – you can alwayscount on GE to help you deliver the highest quality healthcare.For details, please contact your GE representative today.GE imagination at workGE HealthcareInternet – info.lunar@GE Medical Systems Lunar, Europe Kouterveldstraat 20B-1831 Diegem BelgiumPhone: +32-2-719 72 03Fax: +32-2-719 72 05GE Medical Systems, A General Electric Company, going to market as GE Healthcare.General Electric Company reserves the right to make changes in specifications and features shown herein, or discontinue the product described at any time without notice or obligation.Contact your GE Representative for the most current information.SL270EU 11/04 © 2004 GE HealthcareTechnical SpecificationsAvailable Applications and Options AP Spine FemurDualFemurAdvance Hip Assessment with Hip Axis Length, Cross Sectional Moment of Inertia and Femur Strength Index Total Body*Body Composition* (with fat/lean assessment)Dual Energy Vertebral Assessment (DVA)ForearmLateral Spine BMDOrthopedic Hip Analysis Pediatric*Infant Total Body***Small Animal OneVision OneScanComposer with 10-year Fracture Risk assessment Practice Management Report Dexter PDA interface software**Computer Assisted Densitometry (CAD)TeleDensitometry**DICOM (Worklist -Color Print and Store)** Multi User Data Base Access (3/10)**HL7 Bidirectional interface **enCORE™ Software PlatformAdvanced intuitive graphical interfaceMultiple Patient directories with Microsoft Access ®databaseSmartFan™ for scan window optimization and dose reductionAutomated Scan mode selection AutoAnalysis™ for a better precision Customized Analysis for clinical flexibility Exam Comparison processBMD or sBMD results (BMC and Area)Extensive Reference Data> 12,000 subjects – NHANES and several Regional Lunar Reference Data User defined Reference PopulationT-score, Z-score, % Young-Adults and % Age-Match Automated WHO Background evaluationPatient trending with previous exam importation Multiple languages available Multimedia Online HelpTypical Scan Time and Radiation Dose at the best Precision AP Spine : 30 sec : 0.037mGy (< 1%CV) Femur : 30 sec : 0.037 mGy (< 1%CV)Total Body/ Body Comp. : 4 min 30sec: 0.0003 mGy (< 1%CV)Calibration and Quality AssuranceAutomated test program with complete mechanicalsand electronics tests and global measurement calibration Automated QA Trending with complete storageScanning MethodNarrow FanBeam (4,5°angle) with SmartFan, MVIR and TruView algorithmsX-ray characteristicsConstant potential source at 76kV Dose efficient K-edge filterDetector technologyDirect-Digital CZT (Cadmium Zinc Telluride) detector Energy sensitive solid state Array MagnificationNone - Object-plane measuredDimensions (L x H x W) and weight 263 x 111 x 128 cm - 272 kg (Full)202 x 111 x 128 cm - 254 kg (Compact)Vinyl table padExternal shieldingNot required : X-ray safety requirements may vary upon destination. Please inquire with local regulatory authorities.GE Healthcare recommends consulting your local regulatory agency to comply with local ordinances.Environnemental requirements Ambient temperature: 18-27°C Power: 230/240 VAC ±10%, 10A,50/60 HzHumidity: 20% - 80%, non-condensingComputer workstationWindows XP ®ProfessionalIntel processor computer, printer and monitor Contact GE Healthcare or our local distributor for the detailed current configuration and optional hardware.* on full size table only** networking is under the user’s responsibility *** for research only。
钴源 - 北京大学实验室与设备管理部
钴源院系：化学学院钴源辐射化学是研究电离辐射与物质相互作用所产生的化学效应的一门学科。
而高分子辐射化学是高分子化学和辐射化学的交叉领域,因此它是研究电离辐射与单体和聚合物相互作用所产生的化学变化及其效应，包括电离辐射引发的各种聚合、交联、接枝和裂解等。
辐照的方法研究橡胶胶乳的辐射硫化机理及其粉末化工艺；研究辐射硫化超细粉末橡胶在工程塑料增韧和新型热塑弹性体制备中的应用；探索超细粉末橡胶的进一步修饰或改性方法；研究天然高分子材料（纤维素、壳聚糖）的辐射改性；以及高分子材料的辐射交联与辐射降解的机理研究等.9.Advanced Grafted materials for Industrial Applications and Environmental Preservation翟茂林，马骏，彭静，李久强 ZL 201110090533.X 国家 2012.11.21翟茂林，杨仲田，彭静，魏根栓，李久强，黄凌 ZL 200610113538.9 国家 2008.2.20李久强 ZL 200610113539.3 国家 2008.5.21每年有二十名左右的本科生、硕士生、博士生利用此仪器作为必要科研手段进行相关科学研究。
承担研究生实验课程的有关部三年内利用该仪器作为主要科研手段发表学术论文（三大检索） 78 篇，其中代表论文：论文题目期刊名年卷（期）起止页码The identification of radiolytic products of [C4mim][NTf2] and their effects on the Sr2+ extraction.DaltonTransaction201342（12）4299-4305Facile synthesis of well-dispersed graphene by gamma -ray induced reduction of graphene oxide Journal ofMaterialsChemistry201222（26）13064-13069Ionic-liquid-assisted one-step synthesis of Ag-reduced oxidegraphene nanocomposites by gamma inadiation.Carbon201355245-252260。
Delaunay triangulation - Wikipedia, the free encyclopedia
A Delaunay triangulation in the plane with circumcircles shownDelaunay triangulationFrom Wikipedia, the free encyclopediaIn mathematics and computational geometry, aDelaunay triangulation for a set P of points in theplane is a triangulation DT(P ) such that no point in Pis inside the circumcircle of any triangle in DT(P ).Delaunay triangulations maximize the minimum angleof all the angles of the triangles in the triangulation;they tend to avoid skinny triangles. The triangulationwas invented by Boris Delaunay in 1934.[1]For a set of points on the same line there is noDelaunay triangulation (the notion of triangulation isdegenerate for this case). For four or more points onthe same circle (e.g., the vertices of a rectangle) theDelaunay triangulation is not unique: each of the twopossible triangulations that split the quadrangle intotwo triangles satisfies the "Delaunay condition", i.e.,the requirement that the circumcircles of all triangleshave empty interiors.By considering circumscribed spheres, the notion of Delaunay triangulation extends to three andhigher dimensions. Generalizations are possible to metrics other than Euclidean. However inthese cases a Delaunay triangulation is not guaranteed to exist or be unique.Contents1 Relationship with the Voronoi diagram2 d-dimensional Delaunay3 Properties4 Visual Delaunay definition: Flipping5 Algorithms5.1 Flip algorithms5.2 Incremental5.3 Divide and conquer5.4 Sweepline5.5 Sweephull6 Applications7 See also8 References9 External linksRelationship with the Voronoi diagramThe Delaunay triangulation of a discrete point set P in general position corresponds to the dualgraph of the Voronoi tessellation for P . Special cases include the existence of three points on aline and four points on circle.The Delaunaytriangulation with allthe circumcircles andtheir centers (in red).Connecting the centers of the circumcircles produces the Voronoidiagram (in red).d -dimensional DelaunayFor a set P of points in the (d -dimensional) Euclidean space, a Delaunay triangulation is atriangulation DT(P ) such that no point in P is inside the circum-hypersphere of any simplex inDT(P ). It is known [2] that there exists a unique Delaunay triangulation for P , if P is a set of pointsin general position ; that is, there exists no k -flat containing k + 2 points nor a k -sphere containingk + 3 points, for 1 ≤ k ≤ d − 1 (e.g., for a set of points in ℝ3; no three points are on a line, no fouron a plane, no four are on a circle, and no five on a sphere).The problem of finding the Delaunay triangulation of a set of points in d -dimensional Euclideanspace can be converted to the problem of finding the convex hull of a set of points in(d + 1)-dimensional space, by giving each point p an extra coordinate equal to |p |2, taking thebottom side of the convex hull, and mapping back to d -dimensional space by deleting the lastcoordinate. As the convex hull is unique, so is the triangulation, assuming all facets of the convexhull are simplices. Nonsimplicial facets only occur when d + 2 of the original points lay on thesame d -hypersphere, i.e., the points are not in general position.PropertiesLet n be the number of points and d the number of dimensions.The union of all simplices in the triangulation is the convex hull of the points.The Delaunay triangulation contains O (n ⌈d / 2⌉) simplices.[3]In the plane (d = 2), if there are b vertices on the convex hull, then any triangulation ofthe points has at most 2n − 2 − b triangles, plus one exterior face (see Euler characteristic).In the plane, each vertex has on average six surrounding triangles.In the plane, the Delaunay triangulation maximizes the minimum angle. Compared toany other triangulation of the points, the smallest angle in the Delaunay triangulation isat least as large as the smallest angle in any other. However, the Delaunay triangulation does not necessarily minimize the maximum angle.A circle circumscribing any Delaunay triangle does not contain any other input points in its interior.If a circle passing through two of the input points doesn't contain any other of them in itsinterior, then the segment connecting the two points is an edge of a Delaunay triangulation of the given points.The Delaunay triangulation of a set of points in d -dimensional spaces is the projection ofthe points of convex hull onto a (d + 1)-dimensional paraboloid.The closest neighbor b to any point p is on an edge bp in the Delaunay triangulation since the nearest neighbor graph is a subgraph of the Delaunay triangulation.Visual Delaunay definition: FlippingFrom the above properties an important feature arises: Looking at two triangles ABD and BCDwith the common edge BD (see figures), if the sum of the angles α and γ is less than or equal to180°, the triangles meet the Delaunay condition.This is an important property because it allows the use of a flipping technique. If two triangles donot meet the Delaunay condition, switching the common edge BD for the common edge ACproduces two triangles that do meet the Delaunay condition:This triangulationdoes not meet theDelaunay condition(the sum of α and γ isbigger than 180°).This triangulation does not meet the Delaunay condition (the circumcircles contain more than 3points).Flipping the common edge produces a Delaunay triangulation for the four points.AlgorithmsMany algorithms for computing Delaunay triangulations rely on fast operations for detecting whena point is within a triangle's circumcircle and an efficient data structure for storing triangles andedges. In two dimensions, one way to detect if point D lies in the circumcircle of A , B , C is toevaluate the determinant:[4]When A, B and C are sorted in a counterclockwise order, this determinant is positive if and only if D lies inside the circumcircle.Flip algorithmsAs mentioned above, if a triangle is non-Delaunay, we can flip one of its edges. This leads to a straightforward algorithm: construct any triangulation of the points, and then flip edges until no triangle is non-Delaunay. Unfortunately, this can take O(n2) edge flips, and does not extend to three dimensions or higher.[2]IncrementalThe most straightforward way of efficiently computing the Delaunay triangulation is to repeatedly add one vertex at a time, retriangulating the affected parts of the graph. When a vertex v is added, we split in three the triangle that contains v, then we apply the flip algorithm. Done naively, this will take O(n) time: we search through all the triangles to find the one that contains v, then we potentially flip away every triangle. Then the overall runtime is O(n2).If we insert vertices in random order, it turns out (by a somewhat intricate proof) that each insertion will flip, on average, only O(1) triangles – although sometimes it will flip many more.[5] This still leaves the point location time to improve. We can store the history of the splits and flips performed: each triangle stores a pointer to the two or three triangles that replaced it. T o find the triangle that contains v, we start at a root triangle, and follow the pointer that points to a triangle that contains v, until we find a triangle that has not yet been replaced. On average, this will also take O(log n) time. Over all vertices, then, this takes O(n log n) time.[2] While the technique extends to higher dimension (as proved by Edelsbrunner and Shah[6]), the runtime can be exponential in the dimension even if the final Delaunay triangulation is small.The Bowyer–Watson algorithm provides another approach for incremental construction. It gives an alternative to edge flipping for computing the Delaunay triangles containing a newly inserted vertex.Divide and conquerA divide and conquer algorithm for triangulations in two dimensions is due to Lee and Schachter which was improved by Guibas and Stolfi[7] and later by Dwyer. In this algorithm, one recursively draws a line to split the vertices into two sets. The Delaunay triangulation is computed for each set, and then the two sets are merged along the splitting line. Using some clever tricks, the merge operation can be done in time O(n), so the total running time is O(n log n).[8]For certain types of point sets, such as a uniform random distribution, by intelligently picking the splitting lines the expected time can be reduced to O(n log log n) while still maintainingworst-case performance.A divide and conquer paradigm to performing a triangulation in d dimensions is presented in "DeWall: A fast divide and conquer Delaunay triangulation algorithm in E d" by P. Cignoni, C. Montani, R. Scopigno.[9]Divide and conquer has been shown to be the fastest DT generation technique.[10][11]SweeplineFortune's Algorithm uses a sweepline technique to achieve O(n log n) runtime in the planar case.SweephullSweephull[12] is a fast hybrid technique for 2D Delaunay triangulation that uses a radially propagating sweep-hull (sequentially created from the radially sorted set of 2D points, giving a non-overlapping triangulation), paired with a final iterative triangle flipping step. Empirical results indicate the algorithm runs in approximately half the time of Qhull, and free implementations inC++ and C# are available.[13]ApplicationsThe Euclidean minimum spanning tree of a set of points is a subset of the Delaunay triangulation of the same points, and this can be exploited to compute it efficiently.For modelling terrain or other objects given a set of sample points, the Delaunay triangulation gives a nice set of triangles to use as polygons in the model. In particular, the Delaunay triangulation avoids narrow triangles (as they have large circumcircles compared to their area). See triangulated irregular network.Delaunay triangulations can be used to determine the density or intensity of points samplings by means of the DTFE.Delaunay triangulations are often used to build meshes for space-discretised solvers such as the finite element method and the finite volume method of physics simulation, because of the angle guarantee and because fast triangulation algorithms have been developed. Typically, the domain to be meshed is specified as a coarse simplicial complex; for the mesh to be numerically stable, it must be refined, for instance by using Ruppert's algorithm.See alsoBeta skeletonConstrained Delaunay triangulationDelaunay tessellation field estimatorGabriel graphThe Delaunay triangulation of a randomset of 100 points in a plane.Gradient pattern analysisPitteway triangulationUrquhart graphVoronoi diagramReferences^ B. Delaunay: Sur la sph ère vide, Izvestia Akademii NaukSSSR, Otdelenie Matematicheskikh i EstestvennykhNauk, 7:793–800, 19341.^ a b c de Berg, Mark; Otfried Cheong, Marc van Kreveld,Mark Overmars (2008). Computational Geometry:Algorithms and Applications (http://www.cs.uu.nl/geobook/interpolation.pdf) . Springer-Verlag.ISBN 978-3-540-77973-5. http://www.cs.uu.nl/geobook /interpolation.pdf.2.^ Seidel, R. (1995). "The upper bound theorem forpolytopes: an easy proof of its asymptotic version"(/science?_ob=ArticleURL&_udi=B6TYS-3YVD096-C&_user=108429&_coverDate=09%2F30%2F1995&_rdoc=1&_fmt=high&_orig=search&_origin=search&_sort=d&_docanchor=&view=c&_acct=C000059713&_version=1&_urlVersion=0&_userid=108429&md5=70a4159a39ed8ab2c6709025aa77d5de&searchtype=a) . Computational Geometry 5 (2):115–116. doi:10.1016/0925-7721(95)00013-Y (/10.1016%2F0925-7721%2895%2900013-Y) . /science?_ob=ArticleURL&_udi=B6TYS-3YVD096-C&_user=108429&_coverDate=09%2F30%2F1995&_rdoc=1&_fmt=high&_orig=search&_origin=search&_sort=d&_docanchor=&view=c&_acct=C000059713&_version=1&_urlVersion=0&_userid=108429&md5=70a4159a39ed8ab2c6709025aa77d5de&searchtype=a.3.^ Guibas, Lenoidas; Stolfi, Jorge (1985-04-01). "Primitives for the manipulation of general subdivisionsand the computation of Voronoi" (/citation.cfm?id=282923) . ACM. p. 107./citation.cfm?id=282923. Retrieved 2009-08-01.4.^ Guibas, L.; D. Knuth; M. Sharir (1992). "Randomized incremental construction of Delaunay andVoronoi diagrams" (/content/p8377h68j82l6860) . Algorithmica 7: 381–413.doi:10.1007/BF01758770 (/10.1007%2FBF01758770) . /content/p8377h68j82l6860.5.^ Edelsbrunner, Herbert; Nimish Shah (1996). "Incremental Topological Flipping Works for RegularTriangulations" (/content/4gdja72vx1qmg44x/?p=a74909a339d9498cbff326f08b084b4c&pi=1) . Algorithmica 15 (3): 223–241.doi:10.1007/BF01975867 (/10.1007%2FBF01975867) . /content/4gdja72vx1qmg44x/?p=a74909a339d9498cbff326f08b084b4c&pi=1.6.^ Computing Constrained Delaunay Triangulations (/~samuelp/del_project.html)7.^ G. Leach: Improving Worst-Case Optimal Delaunay Triangulation Algorithms.(/viewdoc/download?doi=10.1.1.56.2323&rep=rep1&type=pdf) June 19928.^ Cignoni, P.; C. Montani; R. Scopigno (1998). "DeWall: A fast divide and conquer Delaunaytriangulation algorithm in E d ". Computer-Aided Design 30 (5): 333–341.doi:10.1016/S0010-4485(97)00082-1 (/10.1016%2FS0010-4485%2897%2900082-1) .9.^ A Comparison of Sequential Delaunay Triangulation Algorithms /~jrs/meshpapers/SuDrysdale.pdf10.^ /~quake/tripaper/triangle2.html11.^ S-hull (/paper/s_hull.pdf)12.^ /13.External linksDelaunay triangulation in the Computational Geometry Algorithms Library:Yvinec, Mariette. "2D Triangulation" (/Manual/last/doc_html/cgal_manual/packages.html#Pkg:Triangulation2) . /Manual/last/doc_html/cgal_manual/packages.html#Pkg:Triangulation2. Retrieved April2010.Pion, Sylvain; T eillaud, Monique. "3D Triangulations" (/Manual/last/doc_html/cgal_manual/packages.html#Pkg:Triangulation3) ./Manual/last/doc_html/cgal_manual/packages.html#Pkg:Triangulation3. Retrieved April 2010.Hert, Susan; Seel, Michael. "dD Convex Hulls and Delaunay Triangulations"(/Pkg/Triangulation2) . /Pkg/Triangulation2. Retrieved April 2010."Delaunay triangulation" (/DelaunayTriangulation.html) .Wolfram MathWorld. /DelaunayTriangulation.html.Retrieved April 2010."Qhull" () . . Retrieved April 2010. — Code forConvex Hull, Delaunay Triangulation, Voronoi Diagram, and Halfspace IntersectionShewchuk, Jonathan Richard. "Triangle" (/~quake/triangle.html) ./~quake/triangle.html. Retrieved April 2010. – A Two-DimensionalQuality Mesh Generator and Delaunay TriangulatorKumar, Piyush; Mohanty, Somya. "Triangle++" (/~piyush/scripts/triangle/) . /~piyush/scripts/triangle/. – A C++ wrapper on Triangle"Poly2Tri" (/p/poly2tri/) . Google Code. /p/poly2tri/. Retrieved April 2010. – A sweepline Constrained Delaunay Triangulation(CDT) library, available in ActionScript 3, C, C++, C#, Go, Java, Javascript, Python andRubyRetrieved from "/w/index.php?title=Delaunay_triangulation&oldid=455924497"Categories: Discrete geometry Geometric algorithms Triangles Geometric graphs This page was last modified on 16 October 2011 at 23:22.T ext is available under the Creative Commons Attribution-ShareAlike License; additionalterms may apply. See T erms of use for details.Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profitorganization.。
Ag 原子修饰石墨烯与氮化硼薄膜的第一性
Ag 原子修饰石墨烯与氮化硼薄膜的第一性原理研究陈晓劼，吴其胜，陈乾，王金兰5 （东南大学物理系，南京211189）摘要：本文主要利用第一性原理对二维纳米材料表面修饰A g 原子进行了理论计算研究。
通过计算发现，对单层或双层的石墨烯和氮化硼薄膜表面修饰A g 原子后，它们的性质都有显著的变化。
对于单层或双层石墨烯，表面修饰A g 原子后它们由原先的半金属性转变为金属10 性；而对于单层或双层氮化硼薄膜，在修饰A g 原子后它们从宽带隙半导体转变为了窄带隙半导体。
这种通过表面修饰从而调节材料磁性和能隙的方法可能在未来的自旋电子器件和半导体光学器件方面有潜在的应用价值。
关键词：第一性原理；纳米材料；表面修饰；能隙中图分类号：046915First Principles Study of Surface Modification of Graphene and Boron Nitride Films by an Ag AtomCHEN Xiaojie, WU Qisheng, CHEN Qian, WANG Jinlan(Department of Physics, Southeast University, Nanjing 211189)20 Abstract: First principle calculation is used to investigate the surface modification of twodimensional nano materials with an Ag atom. According to the results of calculation, we find that the properties of monolayer/bilayer graphene and BN film changes significantly after an Ag atom modification. The properties of graphene changes from half-metallic to metallic, while to the case of BN film, it changes from a wide band gap semiconductor to a narrow band gap semiconductor.25 This approach of tuning the magnetism and the band gap of materials by surface modification mayplay an important role in future spintronic devices and semiconductor optical decices.Key words: First principle; Nano materials; Surface modification; Band gap0 引言30 近年来，由于具有各向异性以及维度可调等性质，低维纳米材料（如纳米薄膜、纳米带、纳米管等）吸引了众多科学研究者的重视[1]。
常见的90个英语词根
常见词根act 做，行动acid 酸的，尖酸的ag 移动，做，办理agri 田地，农田ali 别的，其他的ann 年aud 听auto 自动的，自己，本身bio 生命，生物ced 让步，行，走cide,cise 杀，切断claim 喊叫，宣布clar 清楚，明白clud 关闭cog 认识，知道corp 身体，实体，机构crea 创造cred 相信，信任cruc 十字cycl 环形的，圆圈，轮子dem 人民dic 说，言语duc 引导，诱使fac,fact 做，作fer 带，拿来fin 结果，终flect 弯曲geo 地grad 步，走，级graph 写，画，记录器grat 使人高兴的grav 重的helio 太阳hemo 血hibit 持有，拿hum 土，人类hydr 水hypn 睡眠，催眠idio 特殊的，专有的ject 投掷，躺下lect 选，收leg 法律liber 文字，字面loc 地方log 言语，词magn 很大minu 手mar 海，水medi 中间mem 记忆，纪念mini 小migra 迁徙，流动nov 新number,numer 数oper 工作，操作pel 推逐，驱pend 悬挂，垂，待决phil 爱phon 声，音photo 光pict 画popul 人，人民port 运，带，拿pos 放置，地点press 压，按pur 清，纯净rect 正直rupt 破sal 盐sat 足够sci 知scope 观察，看见scrib,scrip 写sect 切割sens 感觉spect 看sphere 球，球体spir 呼吸stereo 固体的，立体的tend 伸展，扩，绷紧ten 使结合在一起，保持住，容纳，注意tract 拖住，抽uni 一，唯一的，统一的vers 转向vest 穿衣，衣服vict,vinc 征服vis,vid 看viv 活的，生活voc 声音，呼唤常见前缀1.表示否定意义的前缀1)纯否定前缀a-, an-, asymmetry(不对称)anhydrous(无水的)dis- dishonest, dislikein-, ig-, il, im, ir, incapable, inability, ignoble, impossible, immoral, illegal, irregularne-, n-, none, neither, nevernon-, noesense neg-, neglectun- unable, unemployment2)表示错误的意义male-, mal-, malfunction, maladjustment(失调)mis-, mistake, misleadpseudo-, pseudonym(假名), pseudoscience3)表示反动作的意思de-, defend, demodulation(解调)dis-, disarm, disconnectun-, unload, uncover4)表示相反，相互对立意思anti-, ant- antiknock(防震), antiforeign,(排外的)contra-, contre-, contro-, contradiction, controflow(逆流)counter-, counterreaction, counterbalanceob-, oc-, of-, op-, object, oppose, occupywith-, withdraw, withstand2.表示空间位置，方向关系的前缀1)a-表示“在……之上”，“向……” aboard, aside,2)by-表示“附近，邻近，边侧” bypath, bypass(弯路)3)circum-, circu-,表示“周围，环绕，回转” circumstance, circuit4)de-,表示“在下，向下” descend, degrade5)en-,表示“在内，进入” encage, enbed(上床)6)ex-, ec-, es-,表示“外部，外” exit, eclipse, expand, export7)extra-,表示“额外” extraction (提取)8)fore-表示“在前面” forehead, foreground9)in-, il-, im-, ir-,表示“向内，在内，背于” inland, invade, inside, import10)inter-, intel-,表示“在……间，相互” i nternational, interaction, internet11)intro-,表示“向内，在内，内侧” introduce, introduce12)medi-, med-, mid-,表示“中，中间” Mediterranean, midposition13)out-,表示“在上面，在外部，在外” outline, outside, outward14)over-,表示“在上面，在外部，向上” overlook, overhead, overboard15)post-,表示"向后，在后边，次” postscript(附言)，16)pre-,表示"在前”在前面” prefix, preface, preposition17)pro-,表示“在前，向前” progress, proceed,18)sub-, suc-, suf-, sug-, sum-, sup-, sur-, sus-,表示“在下面，下” subway,submarine, suffix, suppress, supplement19)super-, sur-,表示“在…..之上” superficial, surface, superstructure20)trans-,表示“移上，转上，在那一边” translate, transform, transoceanic21)under-,表示“在…..下面，下的” underline, underground, underwater22)up-,表示“向上，向上面，在上” upward, uphold, uphill(上坡)3.表示时间，序列关系的前缀1)ante-, anti-,表示“先前，早于，预先” antecedent, anticipate,2)ex-,表示“先，故，旧” expresident, exhusband3)fore-,表示“在前面，先前，前面” foreward, dorecast, foretell(预言)4)mid-, medi-,表示“中，中间” midnight, midsummer5)post-"表示“在后，后” postwar,6)pre-, pri-,表示“在前，事先，预先” preheat, prewar, prehistory7)pro-,表示“在前，先，前” prologue(序幕)，prophet(预言家)8)re-,表示“再一次，重新” retell, rewrite4.表示比较程度差别关系的前缀1)by-,表示“副，次要的” byproduct, bywork(副业)2)extra-,表示“超越，额外” extraordinary,3)hyper-表示“超过，极度” hypersonic(超声波), hypertesion(高血压)4)out-,表示“超过，过分” outdo(超过), outbid(出价过高的人)5)over-，表示“超过，过度，太” overeat, overdress, oversleep6) sub-, suc-, sur-,表示“低，次，副，亚” subeditor, subordinate, subtropical(亚热带)7)super-, sur-表示“超过” supernature, superpower, surplus, surpass8)under-,表示“低劣，低下” undersize, undergrown, un derproduction(生产不足)9)vice-表示“副，次” vicepresident, vicechairman5.表示共同，相等意思的前缀1)com-, cop-, con-, cor-, co-表示“共同，一起”。
mater.res.bull.超声法一步合成碳点
Short communicationSynthesis of fluorescent carbon nanoparticles directly from active carbon via a one-step ultrasonic treatmentHaitao Li a ,1,Xiaodie He a ,1,Yang Liu a ,b ,*,Hang Yu a ,Zhenhui Kang a ,b ,**,Shuit-Tong Lee caInstitute of Functional Nano &Soft Materials (FUNSOM)and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices,Soochow University,Suzhou 215123,China bDepartment of Chemistry,Northeast Normal University,Changchun 130024,China cCenter of Super-Diamond and Advanced Films (COSADF),City University of Hong Kong,Hong Kong SAR,China1.IntroductionRecently,various forms of carbon nanomaterials,such as carbon nanotubes,fullerenes,nanodiamond and other type carbon nanostructures,have been intensively developed not only for their fundamental scientific interests but also for many techno-logical applications [1–9].The emergence of fluorescent carbon nanoparticles (FCNPs)has great potential application in the fields of nanobiotechnology and nanocatalysis [10–16].Compared to traditional quantum dots (QDs)and organic dyes,FCNPs are superior in chemical inertness,stability,potentially less toxicity,and can be modified easily [11–13].These excellent properties make FCNPs being a promising benign fluorescent nanomaterials.Up to now,a variety of routes for preparing FCNPs are reported,including chemical oxidation of arc-discharge single-walled carbon nanotubes (SWCNTs)[10,14],laser ablation of graphite [15–17],electrochemical oxidation of graphite or multiwalled carbon nanotubes (MWCNTs)[18–20],thermal oxidation ofsuitable molecular precursors [21–23,24],supported routes [25],vapor deposition of soot [11,26],proton-beam irradiation of nanodiamonds [27–28]or microwave methods [29]and so on.However,these methods usually involve complex processes,expensive precursors,and severe synthetic conditions,which are unlikely to be extended significantly in the near future.Consequently,the convenient and large scaled fabrication of FCNPs is the urgent challenge in nanotechnology and nanochemistry.Herein,we report a facile and green method to prepare FCNPs by one-step ultrasonic treatment of active carbon in hydrogen peroxide solution.These FCNPs have excellent water-solubility,strong visible emission,and up-conversion photoluminescence (UPL)pared with previous work,the raw materials of present synthetic strategy are inexpensive,commercial avail-able,and easy to obtain.Particularly,such a one-step process is so simple and can be easily carried out on an enlarged scale.2.ExperimentAll the chemicals were purchased from Sigma–Aldrich and Beijing Chemical Reagent (Beijing,China),and were used as received.In a typical experiment,a suitable amount (4.0g)of active carbon was added to hydrogen peroxide (30%,70mL)to form a black suspension.Then the suspension was given a 300W (40kHz)ultrasonic treatment for 2h at room temperature.After that,the dilute suspension was vacuum-filtrated using a mixed cellulose ester membrane with 25nm pores (Millipore)to removeMaterials Research Bulletin 46(2011)147–151A R T I C L E I N F O Article history:Received 31May 2010Received in revised form 19September 2010Accepted 22October 2010Available online 30October 2010Keywords:Optical materials Nanostructures Chemical synthesis LuminescenceA B S T R A C TWater-soluble fluorescent carbon nanoparticles were synthesized directly from active carbon by a one-step hydrogen peroxide-assisted ultrasonic treatment.The carbon nanoparticles were characterized by transmission electron microscopy,optical fluorescent microscopy,fluorescent spectroscopy,Fourier transform infrared spectroscopy and ultraviolet–visible spectrophotometer.The results showed that the surface of carbon nanoparticles was rich of hydroxyl groups resulting in high hydrophilicity.The carbon nanoparticles could emit bright and colorful photoluminescence covering the entire visible-to-near infrared spectral range.Furthermore,these carbon nanoparticles also had excellent up-conversion fluorescent properties.ß2010Elsevier Ltd.All rights reserved.*Corresponding author at:Institute of Functional Nano &Soft Materials (FUNSOM)and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices,Soochow University,Suzhou 215123,China.Tel.:+8651265880956.**Corresponding author at:Institute of Functional Nano &Soft Materials (FUNSOM)and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices,Soochow University,Suzhou 215123,China.Tel.:+8651265880957.E-mail addresses:yangl@ (Y.Liu),zhkang@ (Z.Kang).1These authors contributed equally to this work.Contents lists available at ScienceDirectMaterials Research Bulletinj o u r n a l h o m e p a ge :w w w.e l s e v i e r.c o m /l o c a t e /m a t r e s b u0025-5408/$–see front matter ß2010Elsevier Ltd.All rights reserved.doi:10.1016/j.materresbull.2010.10.013the non-fluorescent deposit [30].After filter treatment,the obtained solution was dark brown,implying the formation of FCNPs.The water-soluble product was purified by evaporating hydrogen peroxide from the solution,and dissolving the remaining solid (FCNPs)in deionized water.The conversion per pass of FCNPs is 6–8%(based on carbon).When the obtained FCNPs were redispersed in water and further refluxed at 1608C for 4h,large sized carbon nanoparticles with diameters in the range of 100–150nm were obtained.All solid samples were dried under vacuum at 608C for 8–10h before the measurement.The Fourier transform infrared (FTIR)spectrum of FCNPs was obtained with a Nicolet 360spectrometer.PL study was carried out on a Fluorolog-TCSPC Luminescence Spectrometer,while UV–vis spectra were obtained with an Agilent 8453UV–vis Diode Array Spectrophotometer.The transmission electron microscopy (TEM)image was obtained with a FEI/Philips Techal 12BioTWIN TEM.The X-ray photoelectron spectra (XPS)were measured by a Kratos AXIS UltraDLD photoelectron spectro-scope.3.Results and discussionFig.1a shows the TEM image of obtained FCNPs,from which we can see that these small FCNPs are well dispersed and their diameters are in the range of 5–10nm.Also the size histogram (Fig.S1)and the AFM image (Fig.S2)of the FCNPs are provided to prove that the FCNPs are well dispersed.Control experimentsindicate that the ultrasonication time has great effect on the morphology of the FCNPs.When the ultrasonic treatment went along for 30min,big carbon nanoparticles with irregular were formed in the solution.Further,the morphology of carbon nanoparticles changed to small spheres (shown in Fig.1a)with ultrasonication time proceeding for 1.5h.As shown in Fig.1b,the FCNPs have an excellent water dispersibility,these FCNPs can freely disperse in water with transparent appearance without further ultrasonic dispersion (so they are called ‘‘water-soluble FCNPs’’).The FCNPs solution is very stable,and there is no nanoparticle precipitation within 6months.The FCNPs solution,even at a very dilute concentration,can emit bright blue-green light when it is irradiated under UV lamp (365nm).This bright blue-green fluorescence of FCNPs is strong enough to be easily seen with the naked eyes (Fig.1c).To further explore their optical properties,the PL spectra of as-prepared FCNPs were assessed.Fig.1d gives the typical PL spectrum of FCNPs with visible and near-infrared (NIR)PL emissions by excitation at 350nm.Notably,PL emission of FCNPs extending into NIR wavelength range was observed (Fig.1d,inset).Meanwhile,the XPS result indicates that the FCNPs contain mainly carbon and oxygen (Fig.1e),and no observable impurities are detected.These results indicate that these small FCNPs are pure and have excellent water-solubility,strong PL emission.Furthermore,the optical property of FCNPs was also investi-gated with fluorescent microscope.Typical specimen for opticalFig.1.(a)The typical TEM image of FCNPs.(b)Digital photograph of FCNPs solution in sunlight.(c)Digital photograph of FCNPs solution with UV lamp (365nm,center)illumination.(d)PL spectrum of carbon nanoparticles prepared from active carbon (excitation wavelength is 350nm),and the inset is the enlarged graph from 700to 1000nm.(e)XPS spectrum of the FCNPs.H.Li et al./Materials Research Bulletin 46(2011)147–151148microscopy was prepared by placing a drop of the aqueous solution on a cover glass and evaporating the water.Notably,different emission colors were found in the same sample with different excitation wavelengths,Fig.2a–d exhibit the typicalfluorescence microscopy images of FCNPs.Different emission of FCNPs in the same sample originate from different excitation:blue,green, yellow,and red emissions under360nm,390nm,470nm,and 540nm excitations,respectively.This kind of small sized FCNPs with stable and strong PL would offer great potential for a broad range of applications,including bio-sensors,biomedical imaging, and so on.Fig.2e shows the typical PL spectra of FCNPs.As shown,all PL spectra of FCNPs exhibit the visible emissions covering blue-to-red wavelength range in the same sample under UV and/or visible excitation.The PL emission ranged from the visible and extended into NIR,were generally broad.Thefluorescent emission peaks shift to longer wavelength with increasing the excitation wavelength.The maximumfluorescence emission intensity can be obtained when excited at350nm.Remarkably,besides the strong PL in visible and NIR range,the FCNPs also exhibit excellent UPL property.Fig.3a depicts the PL spectra of FCNPs excited by long wavelength light(from650to 1000nm)with the up-conversion emissions located in the range from400to700nm.This UPL property of FCNPs should be attributed to the multiphoton active process similar to previous reported carbon dots[16].Compared with the carbon nanopar-ticles prepared in other methods[14–29],the FCNPs prepared in this paper with ultrasound method are relatively inexpensive and have excellent PL properties,such as the strong PL in NIR range and excellent UPL property.These results suggest that FCNPs may be used as a powerful energy-transfer component in photo-catalyst design for applications in environmental and energy issues.The typical UV–vis absorption spectrum of FCNPs is shown in Fig.3b.The absorption band peaked at250–300nm region,and the inset is the enlarged graph of this characteristic absorption peak.This absorption band represents the typical absorption of an aromatic pi system,which is similar to that of polycyclic aromatic hydrocarbons[31].Furthermore,the FTIR spectrum(Fig.S3)was acquired to determine the surface functional groups of the obtained FCNPs. The peaks around3400,3000and1600cmÀ1correspond to the vibrations of C–OH,C–H,and C55O bonds.The asymmetric and symmetric stretching vibrations of C–O–C($1300cmÀ1and $1200cmÀ1)in the carboxylate groups were also detected [17,29].All of above FTIR results indicate that the surface ofFig.2.(a–d)Fluorescence microscopy images of FCNPs under different excitations:a,b,c,and d for360nm,390nm,470nm,and540nm,respectively.(e)PL spectra of FCNPs with UV and visible light excitations.Fig.3.(a)The UPL spectra of FCNPs.(b)UV–vis absorption spectrum of FCNPs,and the inset is the enlarged graph from270nm to330nm.H.Li et al./Materials Research Bulletin46(2011)147–151149FCNPs is full of hydrophilic groups:hydroxy and carboxylic groups.Similar to the earlier reports[3,10],these hydrophilic groups may be due to the oxidation of active carbon by the hydrogen peroxide under ultrasonic conditions,and the intro-duction of such functional groups is the crucial factor for the origin of the FCNPs’PL[3].The quantum yield of the FCNPs with yellow emission was estimated to be about5%by calibrating against quinine sulfate [29,32–33].Further,the as-prepared FCNPs also show good photostability,e.g.the PL properties and appearance remained unchanged after long time(>72h)UV illumination and being stored for several months(>6months)in air at room temperature. Based on the above results,we expect that the present FCNPs are superior to metal-based QDs in terms of high stability,ease of use, low cost,and environmental-friendliness.Consequently,this kind of FCNPs should offer great potential for a broad range of applications,including drug delivery,biomedical imaging,bio-sensors,and photocatalysis[34–37].More experiments were carried out to further investigate the PL properties of FCNPs.Typically,when FCNPs solution was refluxed for4h,large sized carbon nanoparticles with diameters in the range of100–150nm were obtained.Fig.S4shows the TEM image of the large sized carbon nanoparticles,suggesting that the FCNPs strongly aggregate together and form the large sized carbon nanoparticles after refluxing.Fig.S5shows the PL spectra of these particles with a dependence on the excitation wavelengths. Further detailed comparison of typical PL spectra(Fig.2and Fig.S5,Fig.3a and Fig.S6)indicate that there is not obvious difference on PL properties between the FCNPs and the large sized carbon nanoparticles.Since the FCNPs were directly obtained from active carbon,we envision that the formation mechanism of FCNPs is as follows. Ultrasonic waves can generate alternating low-pressure and high-pressure waves in reacting solution,leading to the formation and violent collapse of small vacuum bubbles[38].These cavitations cause high speed impinging liquid jets,deagglomeration and strong hydrodynamic shear-forces.Thus the ultrasonic waves offer great acceleration in the processing of liquid reaction by improving the mixing and chemical reactions speed.In the present ultrasonic reaction system,the active carbon was quickly oxidized by hydrogen peroxide,and then the carbon nanoparticles were peel off duly from active carbon particles.The peel off process of carbon nanoparticles is as follows:when the suspension is irradiated with ultrasound,the alternating expansive and compressive acoustic waves creates bubbles(i.e.,cavities)in liquids,and makes the bubbles oscillate.The oscillating bubbles can accumulate ultra-sonic energy effectively while growing to a certain size(typically tens of mm).Under the right conditions,a bubble can overgrow and subsequently collapse,releasing the concentrated energy stored in the bubble within a very short time.This cavitational implosion is very localized and transient with a pressure of $1000bar[39].So in the effect of high speed impinging liquid jets, deagglomeration,strong hydrodynamic shear-forces and high pressure caused by these cavitations,the carbon nanoparticles were peel off duly from active carbon particles.Moreover,the further experiments show that the present ultrasonic synthetic approach can guarantee the large-scale fabrication of FCNPs.For example,about500mg FCNPs can be obtained from7.0g active carbon raw materials.4.ConclusionsIn summary,the method reported herein provides a new,green and convenient way to prepare a large amount of FCNPs by one-step ultrasonic treatment of active carbon.The FCNPs exhibit stable and strong visible emission and excellent UPL bining free dispersion in water(without any surface modifications)and attractive PL properties,this kind of FCNPs should serve as a promising candidate for a new typefluorescence marker,optical imaging and related biomedical applications. 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基于电聚多巴胺技术一锅法快速构建生物活性界面的研究
·研究简报·基于电聚多巴胺技术一锅法快速构建生物活性界面的研究*李紫珺任科峰＊＊王金磊计剑＊＊(浙江大学高分子科学与工程学系教育部高分子合成与功能构造教育部重点实验室杭州310027)摘要通过精确控制电化学参数采用循环伏安法在中性无氧水环境中制备得到膜厚可控的电聚多巴胺膜，并将这种电聚多巴胺技术与生物活性分子的负载相结合，通过一锅法电聚得到含ＲE DV活性短肽的聚多巴胺活性膜，快速便捷地构建了具有促内皮细胞粘附的生物活性界面．椭圆偏振仪、扫描电子显微镜证实了材料界面上形成了均一的聚多巴胺膜; X射线光电子能谱以及荧光分析结果证实了ＲE DV短肽已负载于电聚多巴胺涂层中．内皮细胞体外黏附实验证实ＲE DV短肽保持了良好活性，可有效促进内皮细胞黏附、铺展及粘着斑的形成．这种一锅法快速制备具有生物活性的电聚多巴胺涂层技术有望为复杂的导电生物材料和装置的多功能界面修饰提供新的途径．关键词电聚合，聚多巴胺，ＲE DV短肽，一锅法，内皮细胞界面修饰方法对生物材料的物理化学性质和生物学应用等具有重要影响．目前常见的材料表面功能化修饰法技术，如层层自组装法［1］、表面等离子体处理［2］、单分子自组装法［3］等往往因为繁琐的制备步骤、苛刻的反应条件或基底材料与修饰基团严格的化学反应配对等原因而受到限制．M essers m it h 等［4］发现仿贻贝粘连蛋白的多巴胺分子在碱性有氧水环境下能够自聚合，在包括金属、金属氧化物、高聚物甚至超疏水表面等多种材料表面沉积成膜，且该过程不受三维结构限制［5～7］，显示出极为巨大的潜在应用，已经成为表面修饰领域的研究热点之一［8］．虽然聚多巴胺形成机理还不甚清楚［9］，但由于其可以进一步与氨基或巯基发生加成反应，由此可以实现膜表面生物活性分子(多糖、生长因子、蛋白质等)的固定［10，11］，因而被广泛应用于生物材料表面修饰领域［12］．然而，该经典聚多巴胺膜的制备极大依赖于碱性有氧环境，并且生物分子的引入需要通过二次反应，整个过程耗时且步骤繁琐．研究发现多巴胺分子沉积成膜的首要条件是多巴胺被氧化为多巴醌［13］，而电化学是调控氧化还原反应的有效手段．即使在中性或弱酸性环境中，多巴胺在电化学作用下也会在电极表面聚合成膜［14］，有研究将酶通过表面固定或同步负载与电聚多巴胺相结合，应用于生物传感器领域［13，15］．本研究以此为启示，将电聚多巴胺技术与具有特异性诱导内皮细胞黏附的ＲE DV生物活性短肽相结合，通过一锅法制备得到具有促进内皮细胞黏附的功能界面．与传统的碱性溶液自聚合方法比较，电聚多巴胺一锅法技术使聚合膜的形成、增长和生物活性分子的捕捉或负载在溶液中同步进行，具有简单快速的特点．该技术有望应用于各种成分、形状的导电性装置表面，为快速构建导电材料活性界面寻求切实可行的途径．1 实验仪器与原料所有电化学实验均在C H I660C电化学工作站上进行．电化学研究采用经典三电极体系，工作电极为金电极或I T O玻璃(有效工作面积为1. 0 cm×1. 0 cm)，涉及细胞实验时使用I T O玻璃，其余均使用金电极．参比电极为饱和甘汞电极(SC E)，铂片作为辅助电极．实验中所给出的电位值均相对于SC E．多巴胺盐酸盐(dopam i ne hydr ochlor i de)购自Si gm a;活性短肽ＲE DV(序列GＲE DVY K，G l y-A r g-G l u-A s p-V al-T yr)和参比短肽ＲE VD(序列GＲE VDY K，G l y-A r g-G l u-V al-A s p-* 2013-06-28 收稿，2013-09-22 修稿;国家自然科学基金(基金号51025312，50830106，21174126，51103126 )和浙江省科技厅优先主题重点社会发展项目(项目号2010c3025-2)资助．＊＊通讯联系人，E-m a il:r enkf@z j u．e du．c n;jiji a n@z j u．e du．c ndo i:10.3724 /S P．J．1105.2014.13225173T yr) 以及荧光标记的活性短肽ＲE DV F I T C购自上海科肽生物技术有限公司．2电聚多巴胺膜(eP DA)及含活性短肽的复合膜(eP DA@ＲE DV)制备工作电极每次使用前用丙酮和水(M illi-Q)依次超声5 m i n，氮气吹干，最后在0.5 m ol/LH2SO4溶液中从－0.2 V到1.4 V进行循环伏安扫描，直到获得稳定的伏安曲线．然后将电极置于1.0 m g/m L 多巴胺的磷酸缓冲溶液(P B S，0.01 m ol/L，pH= 7.4) 中采用循环伏安法聚合一定时间后P B S 清洗3 次，N2吹干．其电位扫描区间为－0.5 ～0.5 V，扫描速度为50 m V/s．对于一锅法负载活性短肽膜的制备，在1.0 m g/m L 多巴胺溶液中加入ＲE V D或ＲE DV短肽( 0.5 m g/m L) ，然后以上述循环伏安法进行电聚4 h 制备得到( eP DA@ＲE DV) 复合膜．对涉及X PS 测试与荧光测试的复合膜的制备，采用ＲE DV/ＲE DV F I T C ( 2∶3，W∶W) 混合的荧光标记体系．所有电聚合反应均在通氮除氧环境下室温中进行．3材料的表征及细胞实验为证实多巴胺在电极表面电聚成膜的过程，椭圆偏振仪( 椭偏，m odel VA SE，J．A．W ool l am I nc．，L i ncol n，N E) 观察了电聚多巴胺膜厚度的动力学增长，场发射扫描电子显微镜( F E-SE M，H it achi S-4800) 观察了膜表面形貌．对于一锅法负载活性短肽体系，采用X射线光电子谱( X PS，K r atos A xis U lt r a D L D) 检测电极表面修饰前后元素组成变化．复合膜中负载的活性短肽在模拟生理环境的P B S( pH= 7.4) 中的稳定性通过孔板荧光计检测( F l uor os kan A scent FL，T her m o Scient ifi c) ．为检验eP DA@ＲE DV复合膜对内皮细胞黏附行为的影响，在eP DA、eP DA@ＲE DV及参照体系eP DA@ＲE VD表面按14000 cel l s/cm2的种植密度种上人脐带静脉内皮细胞( H UV EC s) ，在37 ℃，5%C O2的培养箱中培养1 h．然后多聚甲醛( 3.7%) 室温固定细胞10 m i n 后进行免疫荧光染色．使用罗丹明-鬼笔环肽( 1 ∶ 800，Si gm a) 及4'，6-di am i di no-2-phenyl i ndole( DA P I) ( 2 μg/m L) 分别染色细胞骨架和细胞核．使用一抗(1 ∶400，V9131，Si gm a) 和二抗( 1 ∶500，A11029，I nvi t r ogen) 对纽蛋白( vi ncul i n )染色．细胞在荧光显微镜( Z eiss A xover t200 m i cros copy) 或激光共聚焦显微镜( L ei ca W etz l ar) 下观察，每组3 个平行样，每个样品至少取5 张照片，用I m ageJ软件对图片处理以及细胞计数，统计不同表面的细胞黏附情况．4多巴胺电聚膜的表征首先用椭偏跟踪了电聚多巴胺膜的增长，图1 显示电聚多巴胺膜的厚度在电聚合刚开始的1 h内迅速增大，随后膜厚增速渐缓，至8.3 h 时膜厚达到28. 6 nm．由于聚多巴胺为不导电膜，因此我们认为这个现象的主要原因可能是由于聚多巴胺膜层的电绝缘性阻隔了电极表面与溶液中多巴胺分子的电子传递，导致氧化聚合反应逐渐受到抑制．随后通过SE M观察了电聚多巴胺膜的表面形貌，从图2 可以清楚地观察到电极表面形成了具有一定粗糙度的聚多巴胺膜，但该膜整体均匀平整．这些数据均证明了电聚多巴胺膜的成功制备．F i g． 1 T hickness g r o w t h o f po l ydopa m i ne f abr i ca t e d o ngo l d sur f ace ve r sus ti m e base d o n e l ec t r oche m i s t r y t r ea t m ent5ＲE DV活性短肽的一锅法负载为了进一步探索利用电聚技术便捷地实现复杂功能界面的构建，我们在上述电聚多巴胺膜的技术基础上引入生物活性分子，希望能够一锅法制备生物活性聚多巴胺界面．ＲE DV活性短肽是一种内皮细胞特异性分子，它可以通过与α4β1整合素亚基作用诱导内皮细胞黏附和迁移［16，17］．将多巴胺和ＲE DV短肽分子混合溶液进行一锅法电聚4 h 后，椭偏测试eP DA@ＲE DV膜厚达到23.2 nm，和单纯eP DA膜厚22.4 nm相比无差异，说明ＲE DV短肽对膜厚的增长没有影响，这可能与短肽自身的分子量比较小有关．X PS 谱图( 图3) 显示，经一锅法修饰的表面除了多巴胺沉积膜所含有的C、N、O3 种元素峰外，在160 eV 处还出现了属于ＲE DV-F I T C的S 元素峰，表明多巴F i g． 2 SE M pho t og r aphs o f ba r e go l d (a)a nd po l ydopa m i ne(b)obta i ne d by e l ec t r opo l y m e r i za ti o n f o r 4 hF i g． 3 X PS spec t r a o f e P DA，e P DA@ＲEDV a nd e P DA@ＲEDV'e P DA@ＲEDV'r epresents a m odi fi e d surf ace obta i ne d byi mm e r s i o n o f e P DA-ＲEDV i n P B S f o r 15 h． T he i nse t sho w sa sul f ur pea k a t t he r ange o f100 e V t o200 e V．F i g． 4 Ｒe l eas i ng behav i o r o fＲEDV F I T C f r o m e P DA@ＲEDV fil m i n P B S (pH= 7.4)胺沉积膜通过一锅法成功负载了ＲE DV短肽．为研究ＲE DV短肽负载后其在膜内的稳定性，将该膜置于模拟生理环境的P B S缓冲溶液中，通过荧光强度变化观察复合膜内ＲE DV分子的释放行为．荧光数据表明(图4)，溶液荧光值随时间增加而迅速增大并在6h后趋于平缓，表明膜中有部分ＲE DV短肽释放进入溶液中，然而膜表面的X PS谱图(图3)显示仍有S元素的存在，说明一锅法制备的eP DA@ＲE DV膜在仿生理条件下，最终仍有部分ＲE DV短肽可稳定修饰于膜表面．这种现象可能与ＲE DV短肽负载于聚多巴胺膜的方式有关．数据表明，ＲE DV短肽既有物理吸附和包埋进入膜中，也有部分通过化学共价方式修饰于膜内，短肽的氨基与聚多巴胺的醌式结构发生M i chael 加成反应从而与膜形成共价连接．因此荧光数据表现出ＲE DV短肽短时间内的快速释放．6eP DA@ ＲE DV 复合膜促进内皮细胞黏附我们在eP DA@ＲE DV复合膜表面进行内皮细胞的培养，以验证该种生物活性膜的作用．内皮细胞在3种膜表面黏附1h后，对其细胞骨架进行染色，并对细胞黏附密度和铺展面积进行了统计和分析．从荧光照片数据中，可以看到，内皮细胞均能够在3种表面黏附和铺展(图5)．然而，eP DA@ＲE DV膜表面能够明显促进内皮细胞的黏附和铺展，相对于负载了参照短肽(ＲE VD)的膜与单纯eP DA膜，表现出更高的细胞黏附密度和平均铺展面积(图5，5(a3)、5(b1)、5(b2))．由此说明eP DA@ＲE DV膜中负载的ＲE DV短肽显现出了对内皮细胞特异的促黏附效果．我们进一步考察了黏附后内皮细胞的骨架和黏着斑．图6 为内皮细胞在3种膜表面的F-act i n和vi ncul i n的荧光标记．可以观察到，当内皮细胞在eP DA@ ＲE DV膜表面黏附1h后，可以观察到明显的斑点状的黏着斑结构．而在另2种膜的表面还未能观察到类似的黏着斑，由此说明，ＲE DV短肽的确是通过促进整合素与黏着斑的形成，从而加快内皮细胞的黏附和铺展．这些内皮细胞黏附实验证明，一锅法eP DA@ＲE DV膜中的ＲE DV短肽保持了其特有的生物活性．F i g． 5 M i c r o i m ages o f H UVEC s adhe r e d t o e P DA(a1)，e P DA@ＲEVD(a2)a nd e P DA@ＲEDV(a3)f o r1 hC e ll s w e r e s t a i ne d w it h nuc l eus(blue)a nd F-ac ti n (r e d));T he quant ifi ca ti o n r esul t s o f ce ll dens it y(b1)a nd spreading a r ea(b2)．F i g． 6 C onfoca l i m ages o f H UVEC s adhe r e d t o e P DA(a1 ～c1)，e P DA@ＲEVD(a2 ～c2)a nd e P DA@ＲEDV(a3 ～c3)f o r1 h C e ll s w e r e s t a i ne d f o r F-ac ti n (a1 ～a3)，v i ncul i n (b1 ～b3)a nd m e r ge(c1 ～c3)．7结论多巴胺通过电化学聚合方法可在导电材料表面聚合成膜，并且通过与生物活性分子相结合，一锅法制备带活性短肽ＲE DV的聚多巴胺膜，实现生物活性分子的快速负载．细胞研究结果表明通过上述方式修饰了ＲE DV的膜表面可有效促进内皮细胞的黏附、铺展和黏着斑的形成，提高材料表面细胞亲和力，为电聚技术实现更复杂材料和器件表面的多功能修饰提供依据．该种电聚多巴胺表面修饰技术将在生物材料、医用装置等领域有着潜在的重要应用．ＲEFEＲE N CE S1 D eche r G．Sc i ence，1997，277(5330):1232 ～12372 F av i a P，d’A gos ti noＲ．Sur f C oa t T ec h，1998，98(1):1102 ～11063 H uda ll a G A，M urphy W L．So ft M a tt e r，2011，7(20):9561 ～95714 L ee H，D e ll a t o r e S M，M ill e r W M，M esse r s m it h P B．Sc i ence，2007，318:426 ～4305 W ang J L，Ｒe n K F，C hang H，J i a F，L i B C，J i Y，J i J．M ac r o m o l B i osc i，2013，13(4):483 ～4936 Z hang X，W ang S，X u L，F eng L，J i Y，T ao L，L i S，W e i Y．N anosca l e，2012，4(18):5581 ～55847 Z hang X，L i u M，Z hang Y，Y ang B，J i Y，F eng L，T ao L，L i S，W e i Y．ＲSC A dv，2012，2(32):12153 ～121558 Y e Q，Z ho u F，L i u W．C he m SocＲev，2011，40(7):4244 ～42589 H ong S，N a Y S，C ho i S，Song I T，K i m W Y，L ee H．A dv F unc t M a t e r，2012，22(22):4711 ～471710 L ynge M E，va n de r W es t e n Ｒ，P os t m a A，Stadle r B．N anosca l e，2011，3(12):4916 ～492811 L ee Y B，Shi n Y M，L ee J H，J un I，K ang J K，P a r k J C，Shi n H．B i o m a t e r i a l s，2012，33(33):8343 ～835212 W e i Q，L i B，Y i N，Su B，Y i n Z，Z hang F，L i J，Z hao C．J B i o m e d M a t e rＲes P a r t A，2011，96(1):38 ～4513 H e H，X i e Q，Y ao S．J C o ll o i d I nte r Sc i，2005，289(2):446 ～45414 L i Y L，L i u M L，X i ang C H，X i e Q J，Y ao S Z． T hi n So li d F il m s，2006，497(1-2):270 ～27815 Fu Y，L i P，X i e Q，X u X，L e i L，C he n C，Z o u C，D eng W，Y ao S．A dv F unc t M a t e r，2009，19(11):1784 ～179116 P l ouf f e B D，N j oka D N，H a rr i s J，L i ao J H，H o r i c k N K，Ｒadis i c M，M ur t hy S K．L ang m ui r，2007，23(9):5050 ～505517 W e i Y，J i Y，X i ao L L，L i n Q K，X u J P，Ｒe n K F，J i J．B i o m a t e r i a l s，2013，34(11):2588 ～2599On e-p o t P r e pa r a t io n of Bio a c t ive S u r f a ce b yE lec t r o p oly m e r iz a t io n of Do pam i n eZ i-j un L i，K e-f engＲen*，J i n-l ei W ang，J i an J i*(MO E Ke y La b or at o r y o f Ma cro m o l ec ul ar Synt h es i s and F u n c ti o nali z ati o n，Dep a r tm e nt o fP o lym er S c i en ce and Engi n eer ing，Z h ej iang U ni vers ity，H angz h o u 310027)A b s t ract A n elect r ochem i cal t echnique i nvol ved f aci l e m et hod of cycl i c vol t am m et r i c oxidat i on of dopam i ne t o f abr i cat e t hi cknes s cont r ol l abl e P DA fil m s( eP DA) w as r epor t ed． T his pr oces s w as pr eceded under a neut r al envi r onm ent and i n t he absence of oxygen．M os t i m por t ant l y，w it h precisel y cont r ol l ed elect r ochem i cal par am eters，t his dopam i ne elect r opol ym er i zat i on t echnique can be f ur t her com bi ned w it h bioact i ve m olecules m odi fi cat i on v ia a one-pot s t r at egy t o cons t r uct f unct i onal i z ed sur f aces．B y elect r opol ym er i zat i on of dopam i ne i n a one-pot m i xtur e w it h ＲE DV pept i de，an endot hel i al cel l s( EC s) speci fi c li gand，EC s adhes i on enhanced bioact i ve sur f ace i ncorpor at ed w it h ＲED V w as obtai ned．E lli ps om et r y and s canning elect r on m i cros copy ( SE M) conf i r m ed t he hom ogeneous eP DA fil m f abr i cat i on．X-r ay phot oelect r on spect r os copy( X PS ) and fl uor es cence analys i s r esul t s dem ons t r at ed t he s ucces s f ul i ncorpor at i on ofＲE DV pept i de i nt o eP DA fil m s ( eP DA@ＲE DV) ．C el l s adhes i on exper i m ents s ugges t ed an excel l ent act i vi t y of i ncorpor at edＲE DV pept i de w as r etai ned．F ur t her m or e，EC s exhibi t ed i m pr oved at t achm ent，spreadi ng and vi ncul i n f or m at i on on eP DA@ ＲE DV f unct i onal i z ed sur f ace． T his dopam i ne elect r opol ym er i zat i on ass i s t ed one-pot s t r at egy f or r api d cons t r uct i on of bioact i ve sur f aces provi des an i nnovat i ve approach f or m ul tif unct i onal m odi fi cat i on of com pl i cat ed conduct i ve bi om ater i als and devi ces．K eyw ord s E l ect r opol ym er i zat i on，P ol ydopam i ne，ＲE DV pept i de，O ne-pot，E ndot hel i al cel l s* C o rr esponding autho r s:K e-f engＲe n，E-m a il:r enkf@z j u．e du．c nJ i a n J i，E-m a il:jiji a n@z j u．e du．c n。
一步原位锻烧法制备AgCeO_(2)g-C_(3)N_(4)复合光催化剂及其性能
第58卷第6期 2021年6月撳鈉电子技术Micronanoelectronic TechnologyVol. 58 No.6June 2021D〇I;i〇. 13250/ki.wndz.2021. 06. 004$材料与结构％一步原位锻烧法制备Ag/Ce02/g-C3N4复合光催化剂及其性能程余磊，孙明轩，孙善富，孟祥龙，彭海洋(上海工程技术大学材料工程学院，上海 201620)摘要：以三聚氰胺、硝酸铈和硝酸银为原料，通过一步原位固相烺烧法制备了 Ag/Ce02/g-C3N4复合光催化剂材料。
采用X射线衍射仪（X R D)、X射线光电子能谱仪（X P S)、扫描电子显微 镜（S E M)、透射电子显微镜（T E M)和紫外可见漫反射吸收谱（U V-V is D R S)等对制备出的 样品进行了表征测试。
以亚甲基蓝（M B)为模拟污染物，对样品的可见光催化性能进行了测试。
结果表明，Ag/Ce〇2/g-C3N4的光催化反应速率常数是纯g-C3N4的3.82倍，证明了 A g和Ce02共掺杂的协同效应有效提高了 g-C3N4的光催化性能。
关键词：Ag/Ce02/g-C3N4;复合材料；光催化剂；固相煅烧法；协同效应中图分类号：TB33 文献标识码：A文章编号：1671-4776 (2021) 06-0484-05One-Step In-Situ Calcination Preparation and Properties ofA g/C e02/g-C3 N4Composite PhotocatalystsCheng Yulei，Sun Mingxuan，Sun Shanfu,Meng Xianglong，Peng Haiyang (School o f M aterials E n g in e e r in g，S h anghai University o f E ngineering Scie n ce，S h a n g h a i201620, China )Abstract：With melamine,cerium nitrate and silver nitrate as raw m aterials,Ag/Ce02/g-C3N4 hybrid photocatalysts were prepared through the one-step in-situ solid-phase calcination method.The obtained samples were characterized and tested by X-ray diffractometer (XRD), X-ray photoelectron spectroscope (XPS), scanning electron microscope (SEM), transmission electron microscope (TEM), UV-vis diffuse reflection absorption spectrum (UV-vis DRS),etc.The visible photocatalytic performance of the sample was tested with methylene blue (MB)as the simulated pollutant.The results indicate that the photocatalytic reaction rate constant of Ag/Ce02/g-C3N4 is 3. 82 times higher than that of pure g_C3N4，proving that the synergetic interaction of Ag and Ce02co-doping can effectively improve the photocatalytic performance of g-C3N4.Key words：Ag/Ce02/g-C3N4；composite；photocatalyst；solid-phase calcination m ethod；synergetic interactionEEACC：0550_______收稿日期：2020-12-25基金项目：上海市教育委员会科研创新资助项目（15ZZ092); 2020年上海市市级大学生创新训练资助项目（C S20()50()4); 2020年松江区科委科协资助科普项目（SJKPH2006)通信作者：孙明轩，E-ma丨丨：********************.cn;***************484程余磊等：一步原位锻烧法制备Ag/Ce02/g-C3N4复合光催化剂及其性能〇引言目前，太阳能光催化技术在解决能源危机和环 境污染方面备受研究者的关注。
The Small World Phenomenon An Algorithmic Perspective小世界现象,算法的角度
• Disproves usefulness of Watts & Strogatz model (r=0). • Only for special case of r = k, possible to find short
chains always of length O((log n)2) and dia = O(log n) (dia bound not proved by Kleinberg in this paper). • Cues used in small world networks propounded to be provided through a correlation between structure and distribution of long-range connections.
11
Major Ideas Contributed
• Gives a model of a small world network where local routing is possible using small paths.
• Shows the more generalized results for k dimensions in a subsequent publication.
层次聚类
p5
. . .
Proximity Matrix
– Ward’s Method uses squared error
How to Defy
p1 p1 p2 p3 p4 p2 p3 p4 p5
...
• • • • •
MIN MAX Group Average Distance Between Centroids Other methods driven by an objective function
•
Starting Situation
• Start with clusters of individual points and p1 p2 p3 p4 p5 ... a proximity matrix
p1 p2 p3 p4 p5
. . .
Proximity Matrix
Intermediate Situation
• After some merging steps, we have some clusters
C1 C1 C3 C4 C4 C5 C1 C2 C3 C2 C3 C4 C5
Proximity Matrix
C5
C2
Intermediate Situation
• We want to merge the two closest clusters (C2 and C5) and update the proximity matrix.
– Divisive (分裂的) :
• Start with one, all-inclusive cluster • At each step, split a cluster until each cluster contains a point (or there are k clusters)
Editorial Reviews
Editorial ReviewsReviewEvery major topic is thoroughly covered, and every important concept is defined, described, and illustrated. Conceptually challenging but carefully explained articles will be equally valuable to practicing engineers, researchers and students.-Electronic Servicing & TechnologyThe entire work is heavy on math and includes excellent illustrations. In addition to the usual author and subject indexes, the reader will find indexes to the tables, figures, and equations, the latter being particularly useful. Because areas like communications and biomedical engineering are far from static, this new edition is a worthwhile addition as a technical reference.-John M. Robson…strongly recomm ended…This definitive handbook is a must for any ref erence library.M. S. Roden, California State University, Los AngelesProduct DescriptionIn 1993, the first edition of The Electrical Engineering Handbook set a new standard for breadth and depth of coverage in an engineering reference work. Now, this classic has been substantially revised and updated to include the latest information on all the im portant topics in electrical engineering today. Every electrical engineer should have an opportunity to expand his expertise with this definitive guide.In a single volume, this handbook provides a com plete reference to answer the questions encountered by practicing engineers in industry, government, or academia. This well-organized book is divided into 12 major sections that encompass the entire field of electrical engineering, including circuits, signal processing, electronics, electrom agnetics, electrical effects and devices, and energy, and the em erging trends in the fields of communications, digital devices, computer engineering, system s, and biomedical engineering. A com pendium of physical, chemical, m aterial, and mathematical data com pletes this com prehensive resource. Every major topic is thoroughly covered and every important concept is defined, described, and illustrated. Conceptually challenging but carefully explained articles are equally valuable to the practicing engineer, researchers, and students.A distinguished advisory board and contributors including m any of the leading authors, professors, and researchers in the field today assist noted author and professor Richard Dorf in offering com plete coverage of this rapidly expanding field. No other single volume available today offers this combination of broad coverage and depth of exploration of the topics. The Electrical Engineering Handbook will be an invaluable resource for electrical engineers for years to com e.About the AuthorDorf; Richard C. University of California, Davis, California, USA,Product Details∙ Hardcover: 2752 pages∙ Publisher: CRC; 2 edition (September 26, 1997) ∙ Language: English ∙ ISBN-10: 0849385741 ∙ ISBN-13: 978-0849385742∙ Product Dimensions: 10.3 x 8.7 x 3 inches ∙ Shipping Weight: 7.1 pounds ∙Average Customer Review:2 Reviews5 star :(1) 4 star :(1) 3 star : (0) 2 star : (0) 1 star :(0)› See all 2 customer reviews...∙ 4.5 out of 5 stars See all reviews (2 custom er reviews )∙ Sales Rank: #1,310,414 in Books (See Bestsellers in BooksContents:Circuits Introduction Passive Components ResistorsCapacitors and Inductors Transformers Electrical FusesVoltage and Current Sources Step, Impulse,Exponential and DC Signals Ideal and Practical Sources Controlled Sources Linear Circuit Analysis Voltage and Current Laws Node and Mesh Analysis Network TheoremsPower and Energy Three-Phase Circuits Graph TheoryThe Electrical Engineering Handbook 3rd Edition, 6 Volume Setby Richard C. Dorf, 3672 pp., ISBN: 084932274XThe Electrical Engineering Handbook, 3rd Edition -$209.95 eachEvery electrical engineer should have an opportunity to expand his expertise with this definitive guide.∙Provides the most comprehensive and authoritative reference available on all areas of electrical engineering∙Comes as a six-volume set packaged in an attractive, protective slipcase∙Comprises the latest work of foremost experts from all areas of electrical engineering∙ Presents each article with consistent quality, authority, and level of technical sophisticationTwo-Port Parameters and TransformationsPassive Signal Processing Nonlinear Circuits Diodes and Rectifiers Limiters DistortionLaplace Transform Definitions and Properties ApplicationsState Variables: Concept and Formulation The z-TransformT-XXX Equivalent Networks Transfer Functions of Filters Frequency Response Stability AnalysisComputer Softw are for Circuit Analysis and D esign Analog C ircuit Simulation Parameter Extraction for Analog Circuit Simulation Signal Processing Digital Signal Processing Fourier Tr ansformsFourier Tr ansforms and Fast Fourier Tr ansformDesign and Implementation of Digital Filters Signal R estoration Speech Signal Processing Coding, Transmission and StorageSpeech Enhancement and N oise ReductionAnalysis and Synthesis Speech Recognition Spectr al Estimation and Modeling Spectr al Analysis Parameter Estimation Multidimensional Signal ProcessingDigital Image Processing∙ Maintains consistency with IEEE reader∙Includes new discussions in areas such as nano-technology, fuel cells, embedded systems, and biometricsIn two editions spanning more than a decade, The Electrical Engineering Handbook stands as the definitive reference to the multidisciplinary field of electrical engineering.Our knowledge continues to grow, and so does the Handbook. For the third edition, it has grown into a set of six books carefully focused on specialized areas or fields of study.Each one represents a concise yet definitive collection of key concepts, models, and equations in its respective dom ain, thoughtfully gathered for convenient access.Combined, they consti tute the m ost com prehensive, authoritative resource available.The Electrical Engineering Handbook, 3rd Edition - $209.95 eachCircuits, Signals, and Speech and Im age Processing presents all of the basic information related to electric circuits and components, analysis of circuits, the use of the Laplace transform, as well as signal, speech, and image processing using filters and algorithms.It also examines em erging areas suc h as text to speech synthesis, real-tim e processing, and em bedded signal processing.Electronics, Power Electronics, Opto-electronics, Microwaves, Electro-m agnetics, and Radar delves into the fields of electronics, integrated circuits, power electronics, opto-electronics,electro-m agnetics, light waves, and radar, supplying all of the basic information required for a deep understanding of each area. It also devotes a section to electrical effects and devices and exploresVideo Signal Processing Sensor Array Processing VLSI for Signal Processing Special Architectures Signal Processing Chips and ApplicationsAcoustic Signal Processing Digital Signal Processing in Audio and Electro-acoustics Underwater Acoustical Signal ProcessingArtificial Neural Netw orks Computing Environments forDigital Signal Processing Electronics Introduction Semiconductors Physical Properties DiodesElectrical Equivalent C ircuit Models and D evice Simulators for Semiconductor Devices Semiconductor Manufacturing Processe sTesting Wayne N eedham Electrical Characterization of Interconnections TransistorsJunction Field-Effect Tr ansistors Bipolar TransistorsThe Metal-Oxide Semiconductor Field-Effect Transistor (MOSFET) Integrated C ircuits Integrated C ircuitTechnology Layout, Placement, and Routing Application-Specific Integrated C ircuits Surface Mount Technology Operational Amplifiers Ideal and Practical Models Applications AmplifiersLarge Signal Analysisthe em erging fields of m icro-lithography and power electronics.Sensors, Nano-science, Biomedical Engineering, and Instrum ents provides thorough coverage of sensors, materials and nano-science, instruments and m easurem ents, and biom edical system s and devices, including all of the basic information required to thoroughly understand each area.It explores the em erging fields of sensors, nano-technologies, and biological effects.Broadcasting and Optical Communication Technology explores communications, information theory, and devices, covering all of the basic information needed for a thorough understanding of these areas.The Electrical Engineering Handbook, 3rd Edition - $209.95 eachIt also examines the em erging areas of adaptive estim ation and optical communication.Computers, Software Engineering, and Digital Devices examines digital and logical devices, displays, testing, software, and com puters, presenting the fundamental concepts needed to ensure a thorough understanding of each field.It treats the em erging fields of programmable logic, hardware description languages, and parallel com puting in detail.System s, Controls, Embedded System s, Energy, and Machines explores in detail the fields of energy devices, m achines, and system s as well as control system s.It provides all of the fundamental concepts needed for thorough, in-depth understanding of each area and devotes special attention to the em erging area of em bedded systems.Encom passing the work of the world's foremost experts in their respective specialties, The Electrical Engineering Handbook, Third Edition remains the m ost convenient, reliable source of inform ation available.Small Signal Analysis Active FiltersSynthesis of Low-Pass Forms RealizationGeneralized Impedance Convertors and Simulated Impedances Power ElectronicsPower Semiconductor D evices Power Conversion Power SuppliesConverter C ontrol of Machines Optoelectronics LasersSources and Detectors CircuitsD/A and A/D Converters Thermal Management of ElectronicsDigital and Analog ElectronicDesign Automation Electromagnetics IntroductionElectromagnetic FieldsMagnetism and Magnetic Fields MagnetismMagnetic Recording Wave Propagation Space Propagation Waveguides Antennas Wire ApertureMicr ostrip Antennas Micr owave D evices Passive Microwave Devices Active Micr owave D evices CompatibilityGrounding, Shielding, and Filter ingSpectr um, Specifications, and Measurement Techniques Lightning RadarThe Electrical Engineering Handbook, 3rd Edition - $209.95 eachThis edition features the latest developm ents, the broadest scope of coverage, and new m aterial on nano-technologies, fuel cells, em bedded system s, and biometrics.The engineering community has relied on the Handbook for m ore than twelve years, and it will continue to be a platform to launch the next wave of advancem ents.The Handbook's latest incarnation features a protective slipcase, which helps you stay organized without overwhelming your bookshelf. It is an attractive addition to any collection, and will help keep each volume of the Handbook as fresh as your latest research.$209.95The Electrical Engineering Handbook, 3rd Edition - $209.95 eachPulse RadarContinuous Wave Radar Lightw aveLightw ave WaveguidesOptical Fibers and CablesSolid State CircuitsThree-Dimensional Analysis Computational Electr omagnetics Electrical Effects and Devices Electroacoustic D evices Surface Acoustic Wave Filters UltrasoundFerroelectric and Piezoelectric MaterialsElectrostrictionThe Hall Effect SuperconductivityPyroelectr ic Materials and DevicesDielectr ics and Insulators SensorsMagnetoopticsSmart Mater ialsEnergyConventional Power Generation Distributed Power Generation Transmission。
有机人名反应VilsmeierHaack甲酰化反应
Vilsmeier-Haack reaction
Now
• The application of Vilsmeier-Haack reaction in the synthesis of the agrochemicals such as fenpyroximate，imazaquin，furametpyr was reviewed
Vilsmeier-Haack reaction
Vilsmeier-Haack reaction
References
1 Vilsmeier,A.and Haack,A.Ber.1937,60,119. 2 Campaigne,E.and Archer W. L. Organic Syntheses, Coll.1963,Vol.4,p.331.1953,Vol.33,p.27. 3 Youssefyeh,R.D.Tetrahedron Lett.1964,5,2161. 4 Minkin,V.I.;Dorofeenko,G.N.Russian Chem. Commun.1960,599.(综述) 5 Arnold,Z.;Zemlicka,mun.1959,24,2385. 6 Stéphanie Hesse and Gilbert Kirsch Tetrahedron Lett.2002,43,1213.
Vilsmeier-Haack reaction
• 维尔斯迈尔－哈克反应（Vilsmeier-Haack reaction）是指芳香化合物与二取代甲酰胺在三 氯氧磷作用下，反应生成芳环上甲酰化产物[1]。 该反应只reaction
Vilsmeier-Haack reaction
Vilsmeier-Haack reaction
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TECHNICAL ARTICLEOne-step synthesis of Ag–reduced graphene oxide nanocomposites and their surface-enhanced Raman scattering activityS.Lin,X.S.Zhao,Y.F.Li,C.Liang,a)K.Huang,Y.Sheng,H.Wang,C.X.Ye,X.Xu,Y.F.Zhou,D.Y.Fan, Y.F.Shang,H.J.Yang,R.Zhang,Y.G.Wang,and M.LeiSchool of Science,Beijing University of Posts and Telecommunications,Beijing100876,China(Received20April2014;accepted17June2014)Ag–reduced graphene oxide(Ag/rGO)nanoparticle composites were synthesized through a facileone-step hydrothermal reaction using GO and silver carbonate(Ag2CO3)as raw materials.The homo-geneous silver nanospheres with an average size of50nm well dispersed on the surface of rGO wereobtained without other additives.During the formation process,GO both promotes the dispersion ofAg2CO3in aqueous solution and acts as the substrate of silver cations,and the hydrolysis of Ag2CO3provides silver cations and alkaline condition.Moreover,GO further serves as reducing agent to gen-erate elemental silver in the alkaline condition.The as-prepared materials exhibit excellent surface-enhanced Raman scattering activities when used to detect the Raman signals of R6G absorbed onthe Ag/rGO substrate.©2014International Centre for Diffraction Data.[doi:10.1017/S0885715614000608]Key words:Ag–reduced graphene oxide nanoparticle composites,chemical synthesis,surface-enhanced Raman scatteringI.INTRODUCTIONGraphene and its derivatives have attracted considerable attention owing to their remarkable electrical,optical,thermal, chemical,and mechanical properties.Graphene oxide(GO) is a strongly oxidized form of graphene,retaining the basic framework of graphene and containing abundant oxygen-containing functional groups(Li and Richard,2008;Liu et al.,2011;Wang et al.,2013a,2013b).The interesting struc-ture of GO confirms highly hydrophilia and manipuility to construct a series of nanocomposites for many applications (Chen et al.,2011).As a noble metal,Ag has been the focus of scientific research,possessing excellent optical property and outstand-ing catalytic performance.Interaction between graphene and Ag can improve the surface-enhanced Raman scattering (SERS)activity of Ag–graphene oxide composites(Ag/GO). Considerable attention has been focused on the composites. However,most of the methods still involved multi-steps such as preparation of functional GO(Kumar et al.,2013) and required strong reducing agents,including ethylene glycol,hydrazine,sodium borohydride,and methanol.These synthesis methods were complicated and risky for the environ-ment(Xu et al.,2009;He et al.,2012).In this study,the Ag–reduced graphene oxide(Ag/rGO)composites with uniform size and good dispersity were obtained through an environ-mental friendly one-step hydrothermal route using GO and sil-ver carbonate(Ag2CO3)as the raw materials exclusively.The structure,mechanism,and Raman properties of the compo-sites were investigated in detail.II.EXPERIMENTALThe crucial raw materials GO and Ag2CO3were prepared according to the literature(Huang et al.,2014a,2014b)and Dong et al.(2013),respectively.The Ag/rGO composites were fabricated via a one-step hydrothermal method.In a typi-cal procedure,10mg Ag2CO3powder was added into the cal-culated amount of GO solution in a15ml teflon-sealed autoclave and corresponding amount of deionized water was added to reach80%of autoclave capacity.The mixture should be dispersed by the ultrasonic processing for1h and vigorous stirring for4h.Then the autoclaves would be transferred into oven at80°C for8h and cooled down to room temperature naturally.The products were rinsed with deionized water and ethanol for several times,andfinally dried in vacuum at 40°C for12h.The silver colloid was prepared through a simple reaction reported by Qian et al.(2013).For the detection of SERS activity,a certain amount of various concentrations of solution R6G were mixed with the suspension of Ag/rGO and were allowed to stay for4h after the ultrasonic dispersion process. Finally,the mixture was dropped on the silicon slide and dried for the SERS detection.The structure properties were observed by the X-ray dif-fraction(XRD,PANalytical)andfield emission scanning elec-tron microscope(FESEM,S-4800,Hitachi).The atomic compositions and SERS activity were detected by Raman spec-troscopy(Horiba Jobin Yvon,France),Fourier-transformed infrared spectra(FTIR,Thermo Nicolet),and X-ray photo-electron spectroscopy(XPS,Perkin-Elmer,Al Kαradiation). III.RESULTS AND DISCUSSIONThe phase structure of the product wasfirst confirmed by the XRD.As shown in Figure1(a),GO displays a diffractiona)Author to whom correspondence should be addressed.Electronic mail:cliang@356Powder Diffraction29(4),December20140885-7156/2014/29(4)/356/5/$18.00©2014JCPDS-ICDD356peak at 11.9°,corresponding to the (001)-plane of the hexago-nal graphite structure (Xu et al.,2009;Qian et al.,2013),and the diffraction peaks of prepared Ag 2CO 3agree well with those of the standard monoclinic Ag 2CO 3(JCPDS No.26-0339).Four main peaks at 2θ=37.9°,44.1°,64.3°,and 77.2°emerge,which correspond to the (111),(200),(220),Figure 1.(Color online)(a)XRD patterns of GO,Ag 2CO 3,and Ag/rGO;(b –e)SEM images of pure Ag 2CO 3,GO sheets,hydrothermal treated pure Ag 2CO 3,and Ag/rGO composites,respectively.Figure 2.(Color online)(a)Raman,(b)FTIR spectra of GO and Ag/rGO,(c,e)XPS spectra of C1s peaks,and (d,f)Ag3d peaks for GO and Ag/rGO,respectively.357Powder Diffr.,Vol.29,No.4,December 2014One-step synthesis of Ag –reduced graphene oxide nanocomposites357and(311)planes of the cubic Ag(JCPDS no.99-0094), respectively,indicating that the metallic Ag is formed after the hydrothermal process.However,no obvious diffraction peaks of rGO are observed,which may be because of the relatively low content of rGO or the exfoliation of rGO(Xu et al.,2009).The morphology of the product was examined by FESEM.The rod-like Ag2CO3particles[Figure1(b)]display a relatively smooth surface and uniform size,and GO sheets [Figure1(c)]exhibit the typical crumpled structure.As shown in Figure1(d),no Ag nanospheres emerge in the absence of GO sheets.Inspiringly,the rod-like particles disap-pear,whereas the new sphere-like particles with average size of50nm covered with rGO sheets[Figure1(e)]generate after the GO-assisted hydrothermal reaction.It is believed that the anisotropic growth is inhibited with the wrapping GO,leading to the formation of Ag spheres.To further investigate the formation process,correspond-ing Raman,FTIR,and XPS spectra were measured.Two prominent peaks[Figure2(a)]correspond to D band about 1330cm−1and G band about1590cm−1for GO sheets are observed,which is assigned to the disorder originating from functional groups and E2g mode of C sp2atoms,respectively. The intensity ratio I D/I G of GO is1.13.However,the I D/I G of Ag/rGO composites decreases to1.02after the hydrothermal treatment.It is suggested that the oxygen-containing func-tional groups decrease and the GO is partially reduced into rGO(Kumar et al.,2013;Liu et al.,2013).In addition,the intensities of the D and G bands of Ag/rGO composites obviously increase in comparison with those of GO,which is because of the SERS activity(Ma et al.,2011;Huang et al.,2014a,2014b).The FTIR spectrum of GO and Ag/rGO composites is shown in Figure2(b).The characteristic absorption peaks of GO appear at3436,1713,1596,1401,and1027cm−1,corre-sponding to the–OH stretching vibrations,C=O stretching of COOH groups,sp2C–C bonds,O–H deformations of the C–OH groups,and C–O stretching vibrations,respectively (Yuan et al.,2012).The most obvious difference between the two spectrums is the intensity weakening of the vibration of C–OH groups,which reveals that C–OH groups play an important role for the reduction process of silver cations to metallic silver.To investigate the inner structure and the formation mech-anism,XPS spectra of GO and Ag/rGO composites are exhib-ited in Figures2(c)–2(f).The deconvoluted peaks of C1s XPS spectrum of GO[Figure2(c)]arising from284.7,286.9,and 288.6eV indicate the components of C–C/C=C(graphene bonding),C–O(hydroxyl and epoxy),and C=O(carboxyl), respectively(Yuan et al.,2012).As to Ag/rGO composites [Figure2(e)],the intensity of oxygen-containing functional groups decreases significantly.The elimination of hydroxyl, epoxyl,and carboxyl confirms the reduced process of GO to rGO and the important role of these functionalgroups.Figure3.(Color online)Schematic illustration of the mechanism for Ag/rGO composites.358Powder Diffr.,Vol.29,No.4,December2014Lin et al.358Meanwhile,two new peaks at 368.4and 374.4eV can be detected corresponding to the binding energies of Ag3d 3/2and Ag3d 5/2in the Ag3d XPS spectrum of Ag/rGO compo-sites [Figure 2(f )].The separation of spin-energy is measured to be 6eV,further con firming the formation of metallic silver (Ma et al.,2011).The consistent results illustrate that GO have played an important role during the hydrothermal formation process of Ag/rGO composites.First,GO promotes the dispersion of Ag 2CO 3in aqueous solution.The large number of functional groups can adsorb the particles in solution,making sure the Ag 2CO 3suf ficient decentralize.Another point,GO can be treated as a consumer of silver cations via combination by electrostatic adsorption and π–πorbitals interaction.The decreasing concentration of silver cation coupling with high temperature of 80°C,promotes hydrolysis of Ag 2CO 3to gen-erate Ag +,HCO 3−,and OH −,resulting in the alkaline con-dition.Besides,the functional groups,acting as anchor sites of silver cations,enable the subsequent in situ formation of Ag nanoparticles (Pasricha et al.,2009).Furthermore,the functional groups play the role of reducing agent.During the hydrothermal process,the hydroxyl groups based on the hexagonal basal plane are equivalent to phenolic entity in alkaline condition,with a protonation to generate strongly activated phenolate anions and achieve the electrophilic aro-matic substitution reaction to generate elemental silver by transferring electrons to silver cations (Manuel et al.,2005).In addition,GO is reduced to rGO,forming Ag/rGO compo-sites.As Figure 3shows,with the interaction of oxygen-containing functional groups,the silver ions are adsorbed on the rGO sheets and form Ag nanoparticles to achieve one-step synthesis in the absence of additional reductant.The SERS activity of as-prepared samples was further tested by R6G as the probing molecules.As Figure 4(a )shows,the strong characteristic Raman peaks of R6G on the Ag/rGO substrate at 614,777,921,1132,1186,1312,1364,1510,1579,and 1650cm −1observed in the spectra A are in good agreement with the previous reports.By contrast,the SERS signals of R6G on the silver colloid are signi ficantly reduced.Moreover,we cannot find any characteristic peaks of R6G on the GO bined with the above analysis,we consider that the better SERS activity of Ag/rGO results from the aggregated structures of Ag nanoparticles coupling with rGO.SERS spectra of R6G with different concentrations on Ag/rGO are displayed in Figure 4(b ).It is obvious that theSERS signals decrease with decreasing the concentration of R6G,and the spectrum 3becomes similar to rGO with further decrease.However,the bands at 614,777,and 921cm −1are still sensitive to detect the concentration of R6G.IV.CONCLUSIONSIn summary,Ag/rGO composites have been successfully fabricated through a facile one-step hydrothermal method using GO and Ag 2CO 3as starting reactants.The GO sheets are identi fied to serve as the dispersant,stabilizer,and redu-cing agent,whereas the Ag 2CO 3provides silver cations and alkaline condition.Silver cations are reduced into metallic Ag by hydroxyl groups mainly in the alkaline condition,and then causing the generation of rGO because of the decrease of oxygen-containing functional groups.The as-prepared Ag/rGO composites are testi fied to be an excellent substrate to probe molecules.The Ag/rGO composites exhibit better SERS activity than Ag colloid owing to the strong inter-action of Ag and rGO.ACKNOWLEDGEMENTSThis work was financially supported by the Program for New Century Excellent Talents in the University (grant no.NCET-13-0684),Fund of State Key Laboratory of Information Photonics and Optical Communications (Beijing University of Posts and Tele-Communications,People ’s Republic of China),National Natural Science Foundation of China (Grant numbers 61376018,51102019,61177085,61377097,61274012,and 51272031).Chen,J.L.,Zheng,X.L.,Wang,H.,and Zheng,W.T.(2011).“Grapheneoxide –Ag nanocomposite:in situ photochemical synthesis and application as a surface-enhanced Raman scattering substrate,”Thin Solid Films 520,179–185.Dong,H.J.,Chen,G.,Sun,J.X.,Li,C.M.,Yu,Y.G.,and Chen,D.H.(2013).“A novel high-ef ficiency visible-light sensitive Ag 2CO 3photocatalyst with universal photodegradation performances:simple synthesis,reaction mechanism and first-principles study,”Appl.Catal.B:Environ.134,46–54.He,Y.,Cui,H.,and Mater,J.(2012).“Synthesis of highly chemiluminescentgraphene oxide/silver nanoparticle nano-composites and their analytical applications,”J.Mater.Chem.22,9086–9091.Huang,K.,Lei,M.,Wang,Y.J.,Liang,C.,Ye,C.X.,Zhao,X.S.,Li,Y.F.,Zhang,R.,Fan,D.Y.,and Wang,Y.G.(2014a ).“GreenhydrothermalFigure 4.(Color online)(a)SERS spectra of R6G (10−6M)solution on the substrate of Ag/rGO (A),Ag colloids (B),and rGO (C).(b)SERS spectra of R6G of various concentrations on the Ag/rGO substrate.359Powder Diffr.,Vol.29,No.4,December 2014One-step synthesis of Ag –reduced graphene oxide nanocomposites359synthesis of CeO2NWs-reduced graphene oxide hybrid with enhanced photocatalytic activity,”Powder 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