乳液模板-自组装法制备石墨烯/聚苯乙烯导电复合材料

利用乳液模板-静电自组装法,以甲基丙烯酰氧乙烯氯化铵(DMC)接枝改性的聚苯乙烯阳离子微球(PS+ )为基体模板、石墨烯为导电介质,利用氧化石墨烯(GO)与PS+间强烈的静电相互作用直接在水中共组装,通过水合肼原位还原(in-situreduction)成功制备了纳米石墨烯片(GNs)填充的聚苯乙烯(PS)导电复合材料。复合材料断口扫描电镜(SEM)和电性能结果表明,静电自组装有利于形成较为完善的石墨烯导电网络,GNs/PS复合材料具有极低的导电逾渗值(0.09%(体积分数))和较高的饱和导电率(25.2S/m)。结合表面zeta电位、复合物微观形貌的表征,对组装机理和结构-性能关系进行了讨论。此外,热重热分析(TGA)结果表明,石墨烯的加入有效地改善了材料的热稳定性。     

三维聚苯乙烯/聚苯胺/石墨烯复合微粒的制备及电化学性能

为扩展石墨烯的宏观应用,制备性能优异的三维聚苯乙烯/聚苯胺/石墨烯(PS/PANI/graphene)复合微粒具有重要意义.以聚苯乙烯微粒为模板,通过2种浓度苯胺单体的原位生长得到2种聚苯乙烯/聚苯胺复合微粒,再利用氧化石墨烯与苯乙烯/聚苯胺微粒间的静电、共轭相互作用制备三维PS/PANI/graphene复合微粒.利用红外光谱(FTIR)、扫描电镜(SEM)、X射线衍射(XRD)、热重分析(TG)对其微观形貌、结构进行表征,利用电化学测试对三维复合微粒电化学性能进行测试.结果表明,复合材料保持了聚合物微粒的基本形貌,具有三维结构,并有优异的比电容(578 F/g)和循环稳定性(循环900次,容量保持81.5%),其电性能远优于单纯石墨烯和聚苯胺.     

电化学制备有序聚苯胺／聚苯乙烯复合材料

利用垂直沉积自组装技术在氧化铟锡（ITO）导电玻璃基底上制备出高度有序的聚苯乙烯（PS）薄膜,以此为模板,在三电极体系中应用循环伏安法,控制电势在-0．3-0．9V之间,以20mV／S的扫描速度,在有序排列PS薄膜的表面电化学沉积聚苯胺（PANI）,成功制备出了聚苯胺／聚苯乙烯（PS／PANI）有序导电高分子复合材料,通过紫外-可见光分光光度计、循环伏安法、场发射扫描电镜、x射线衍射仪进行表征,结果表明,制得的PS／PANI复合材料粒径均匀、排列有序、呈密堆积结构,可为制备具有有序中空或大孔膜产物提供较理想的模板。     

染料敏化太阳能电池用CuO-NRs/GNs复合对电极的研究

采用均匀沉淀法制得的氧化铜纳米棒(CuO-NRs)与石墨烯(GNs)浆料复合,利用电流体动力学技术(EHD技术)在FTO导电玻璃基片上制备CuO-NRs/GNs复合对电极。通过XRD物相分析,和SEM、TEM结构表征,表明CuO-NRs/GNs复合薄膜具有多孔的网络结构,通过一系列电化学性能测试,证明CuO-NRs/GNs复合对电极具有较高的电催化活性,和较快的电子传输速率,由CuO-NRs/GNs复合对电极组装的DSSC光电转换效率(2.57%)达到了与Pt对电极(3.46%)相当的水平。     

聚吡咯/石墨烯复合导电材料的制备及性能表征

利用电化学合成和化学还原方法制备了超级电容器用聚吡咯/石墨烯(PPy/GNs)复合电极材料,分别对比了恒电流和脉冲电流条件下石墨烯对电极材料电化学性能的影响,断口形貌及电性能测试结果表明,石墨烯因其良好的导电性能可有效提高电极的比容量,与聚吡咯(PPy)相比,恒电流制备的PPy/GNs(DC-PPy/GNs)电极比容量提高了13.5%。另外发现,脉冲电流制备的PPy/GNs(PC-PPy/GNs)超级电容器具有更大的比容量和更好的循环稳定性。导通时间为100ms时,PC-PPy/GNs复合电极材料在100mV/s的扫描速率下比容量可达280F/g。     

聚酰亚胺辅助制备高定向石墨烯基全炭泡沫及其在导热聚合物复合材料中的应用（英文）

石墨烯及其衍生物具有高纵横比的二维层状结构,在加工过程中通常倾向于水平排列。因此,石墨烯基复合热界面材料虽然具有较高的面内热导率,但其表现出的低面外热导率难以满足实际应用需求。本文通过定向冷冻策略制备了竖直排列的聚酰亚胺/石墨纳米片(PG)导热骨架以提高聚合物复合材料的面外热导率,其中石墨纳米片(GNs)为高导热石墨烯薄膜的粉体边角料。在该过程中,采用水溶性聚酰胺盐溶液直接分散疏水的GNs,热亚胺化后获得的聚酰亚胺在辅助GNs定向排列的同时经石墨化处理转变为人造石墨。同时,GNs的引入提高了PG骨架的有序度和密度,进一步提高了聚二甲基硅氧烷(PDMS)基复合材料的强度和导热性能。结果表明,所制备的PDMS/PG复合材料(PG:21.1%)的面外热导率达14.56 W·m^-1·K^-1,是纯PDMS的81倍。这种简便的聚酰亚胺辅助二维疏水填料定向排列的方法为各向异性热界面材料的规模制备提供了思路,同时实现了石墨烯薄膜边角料的再利用。     

以石墨烯气凝胶为导电相的压电阻尼复合材料

阻尼材料在减振降噪领域有着极其重要的应用,而压电阻尼复合材料能够在普通阻尼材料摩擦损耗基础之上进一步引入力-电-热损耗,从而提高基体材料的阻尼性能,使其在主动和被动减震方面备受青睐。但是通常为了达到导电渗流阈值,需要添加大量的导电相。采用模板辅助氧化石墨烯自组装的方式制备了三维石墨烯气凝胶,以此作为导电相,以聚氨酯/聚甲基丙烯酸丁酯/聚甲基丙烯酸甲酯IPN共聚物作为基体,锆钛酸铅压电陶瓷作为压电相,制备了压电阻尼复合材料。三维石墨烯气凝胶的使用,由于其本身三维导电网络的存在,使得制备的压电阻尼复合材料可以在很低的导电相含量下达到导电渗流阈值,将压电陶瓷产生的电能转化为热能损耗掉,有效拓宽了基体材料的阻尼温域和提高了材料室温下的阻尼性能。     

石墨烯/聚氨酯复合材料的制备及其力学性能分析

采用聚四氢呋喃作为软段,2,4-甲苯二异氰酸酯为硬段,MOCA为扩链剂,物理剥离的石墨烯(GNs)和硅烷偶联剂(APTES)改性的氧化石墨烯(GO)为填料合成了石墨烯/聚氨酯复合材料。通过溶胀平衡实验探究石墨烯与聚氨酯基体的相容性对力学性能的影响。结果表明,两种石墨烯的加入均能提高复合材料体系的交联密度。复合材料的拉伸强度均先增大后减小,损耗因子峰值增大。但改性GO能使阻尼温域拓宽,并且随着添加量的增加,改性GO组的体系交联密度、溶胀比、拉伸强度保持率等均优于GNs组。     

3D多级孔rGO/TiO2复合材料的构筑及其光催化性能研究

研究以聚苯乙烯(PS)微球为模板、氧化石墨烯(GO)和钛酸四丁酯(TBT)为原料, 采用溶胶-凝胶法, 利用GO与PS上的官能团和TiO₂前驱体的多重配位反应, 制备了3D多级孔rGO/TiO₂(PS)复合材料。通过不同手段对样品的结构和形貌进行表征, 研究了PS添加量对rGO/TiO₂复合材料晶体结构、微观形貌及光催化性能的影响。分别在模拟紫外光和可见光下, 以盐酸四环素(TTCH)为目标污染物对不同PS加入量制备的3D多级孔rGO/TiO₂(PS)复合材料的光催化性能进行评价, 并在模拟可见光下, 对3D多级孔rGO/TiO₂(5wt%PS)复合材料进行了多次循环回收测试。结果表明: rGO/TiO₂(PS)复合材料具有3D多级孔块体结构, GO作为基体的增强相通过Ti-O-C键保持多级孔刚性骨架结构的稳定。引入PS增大了rGO/TiO₂(PS)复合材料的比表面积, 3D多级孔rGO/TiO₂(7wt% PS)复合材料对TTCH吸附效率最高, 而3D多级孔rGO/TiO₂(5wt%PS)复合材料光催化活性和稳定性最高, 且经过4次循环回收测试, 其光催化效率仍达81.02%; 模板剂PS的最佳引入量为5wt%。     

Al(OH)3-磷杂化聚合物/聚苯乙烯复合材料的协同阻燃效应

采用二氯磷酸苯酯(PDCP)、乙二醇(EG)、甲醇为原料,经逐步聚合得到磷元素杂化聚合物(OPP),将OPP和氢氧化铝(ATH)与聚苯乙烯(PS)掺杂共混制备氢氧化铝-磷元素杂化聚合物/聚苯乙烯阻燃复合材料(ATH-OPP/PS)。利用FTIR、凝胶渗透色谱(GPC)表征OPP的结构及平均分子量,通过热重分析、极限氧指数(LOI)和微型量热仪、扫描电子显微镜(SEM)、X射线光电子能谱仪(XPS)对复合材料及炭层进行分析,利用Flynn-Wall-Ozawa(FWO)法计算ATH-OPP/PS的热降解活化能(Ea)。结果表明,ATH-OPP体系能协同提高复合材料的热稳定性和LOI,降低复合材料的总热释放量(THR)和热释放速率峰值(PHRR),Ea随降解转化率增大而增大。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.