电致变色器件关键材料凝胶聚合物电解质研究进展

凝胶聚合物电解质是构成电致变色器件(ECD)的关键材料,其在器件中作为电极间的传导介质,为电致变色反应提供补偿离子。利用不同基体材料制备的凝胶聚合物电解质对提高电致变色器件性能具有重要影响。综述了聚环氧乙烷(PEO)、聚丙烯腈(PAN)、聚甲基丙烯酸甲酯(PMMA)、聚偏氟乙烯(PVDF)、聚偏氟乙烯-六氟丙烯(PVDF-HFP)、聚乙烯醇缩丁醛(PVB)及生物材料作为凝胶电解质聚合物基体的导电机理。阐述了它们作为电致变色器件电解质层对离子电导率、透光度、电致变色性能的影响。最后对凝胶聚合物电解质未来发展趋势进行了展望。     

深度调剖提高原油采收率的聚丙烯酰胺类凝胶体系综述

在石油开采过程中,聚丙烯酰胺类交联凝胶体系是由堵水和调剖发展起来的一种新型体系。它是利用聚合物的交联反应形成可动凝胶,减缓水的窜流,驱替水驱残余油。本文将评述可应用于深井开采的苛刻油藏环境下的聚丙烯酰胺类凝胶体系的机理,并着重介绍国内外的最新研究——聚丙烯酰胺纳米复合水凝胶、聚电解质配合纳米粒子聚丙烯酰胺水凝胶和低毒性有机交联两性聚丙烯酰胺水凝胶等。     

可生物降解聚天冬氨酸水凝胶的合成及性能

采用两步交联法合成了可生物降解聚天冬氨酸水凝胶。首先用赖氨酸作为内交联剂对聚丁二酰亚胺进行开环反应,以侧基的形式引入聚合物链中,然后用戊二醛为表面交联剂进行进一步交联反应,从而形成水凝胶。研究了反应温度、时间、赖氨酸及戊二醛用量对水凝胶溶胀性能的影响。并对水凝胶的溶胀机理进行了初步的探讨,结果表明,溶胀过程属于非Fickian扩散。pH敏感性测试表明水凝胶在pH=3.4时收缩,而在pH<3.4和pH>3.4时溶胀,且在中性和碱性条件下的溶胀率大于在酸性条件下的溶胀率。     

聚丙烯酰胺/聚甲基丙烯酸(2-甲基氨基)乙酯高强度双网络水凝胶的制备及pH响应性

利用两步法合成了聚丙烯酰胺(PAM)/聚甲基丙烯酸(2-甲基氨基)乙酯(PDMAEMA)双网络水凝胶,第一网络为锂藻土(Laponite)物理交联的PAM纳米复合水凝胶,第二网络为化学交联剂N,N-亚甲基双丙烯酰胺(BIS)交联PDMAEMA。研究了2种网络相对含量、纳米黏土Laponite用量、化学交联剂BIS用量对水凝胶强度和pH响应性的影响。研究结果表明,PAM/PDMAEMA双网络水凝胶具有高强度,改变单体AM和DMAEMA的配比、交联剂的用量,其拉伸强度在36～91.9 kPa范围内可调。PAM/PDMAEMA双网络水凝胶还具有灵敏的pH刺激响应性,在pH=4时双网络水凝胶溶胀度急剧下降。     

对电场响应的聚电解质凝胶响应机理及应用

聚电解质凝胶是在聚合物网络结构中含有化学键结合的离子化基团的水凝胶。有些聚电解质水凝胶在施加电场的电解质溶液中能发生形变。本文叙述了对电场刺激发生响应的聚电解质凝胶的发展、响应机理，以及在人工肌肉、自动开关元件、药物释放体系方面的应用，并指出将其应用于组织工程的可行性。     

高强度超拉伸全物理交联双网络水凝胶的制备与性能

以锂藻土(Laponite)与聚丙烯酰胺(PAM)间的氢键交联作用网络形成第1网络、以三价铁离子(Fe~(3+))与海藻酸钠(Alginate)间的离子交联作用形成第2网络,制备了锂藻土-聚丙烯酰胺/Fe~(3+)-海藻酸钠(Laponite-PAM/Fe~(3+)-Alginate)全物理交联双网络水凝胶。通过扫描电镜表征了Laponite-PAM/Fe~(3+)-Alginate双网络水凝胶的微观结构,探究了Fe~(3+)浓度和锂藻土含量对Laponite-PAM/Fe~(3+)-Alginate双网络水凝胶力学性能的影响,并通过拉伸-回复测试表征了水凝胶的回复性能和抗疲劳性能。结果表明,Laponite-PAM/Fe~(3+)-Alginate全物理交联双网络水凝胶内部具有致密的三维网络结构,其断裂强度可达2.4 MPa,断裂伸长率可达2600%,韧性可达44.8 MJ/m~3,具有优异的力学性能、良好的回复性能及抗疲劳性能。     

三维结构聚丙烯酰胺/聚乙烯醇水凝胶的合成及其在超级电容器中的应用

分别以过硫酸铵(APS)和N-N二甲基双丙烯酰胺(NMBA)作为引发剂和交联剂引发交联具有三维网络结构的聚丙烯酰胺/聚乙烯醇(PAM-PVA)水凝胶,将该水凝胶浸泡在6mol/L的KOH溶液中不同时间,制备凝胶聚合物电解质,并组装成双电层超级电容器。采用循环伏安、恒流充放电、交流阻抗等电化学测试技术对组装的超级电容器进行全面的性能研究,采用蓝电监测系统测试组装的超级电容器的稳定性。结果表明,以2.0g聚乙烯醇和10.0g丙烯酰胺反应制得的凝胶基体在吸收72h电解质溶液后组装的超级电容器性能最优,其比电容可达230F·g~(-1),5 000次充放电之后其循环保持率仍高达98%。     

增韧水凝胶的研究进展

水凝胶由交联聚合物网络和大量水组成。与生物组织类似的结构,使得水凝胶广泛应用于人类生活和生物医药领域。但现今水凝胶的进一步应用仍然受限于其较差的力学性能。为此,文中综述了近些年科研工作者们在水凝胶增韧方面的研究进展,并从增韧机理出发,划分为杂交交联、互穿网络、高功能交联剂及其他新型体系,深入分析各种能量耗散机理。此外,还展望了水凝胶未来的增韧机理的发展方向及前景。     

聚合物凝胶电解质在镍氢电池中的应用

研究了一系列交联聚丙烯酸与KOH形成的水凝胶电解质的电化学特性。研究表明,聚合物凝胶电解质具有和KOH水溶液十分接近的离子电导率和稳定的电化学窗口,而且用聚合物凝胶电解质制作的Ni／MH试验电池具有更好的充放电循环特性。扫描电镜研究也证明,使用聚合物凝胶电解质的电池正负极材料腐蚀较小,没有明显的粉化,因此在Ni／MH电池领域将有广阔的应用前景。     

锂离子电池用凝胶聚合物电解质研究进展

凝胶聚合物电解质既具有固态聚合物电解质良好的力学加工性能和安全性能,又具有传统液态电解质较高的室温离子电导率。但凝胶聚合物电解质由于室温离子电导率低、力学强度较差的缺点限制了其在锂离子电池上的应用。结合目前研究的最新进展,本文针对几种常用凝胶聚合物电解质体系聚氧化乙烯、聚丙烯腈、聚甲基丙烯酸甲酯、聚偏氟乙烯-六氟丙烯和聚乙烯醇缩醛进行了综述,对其制备方法以及通过聚合物调控、加入无机填料和复合离子液体进行改性处理做了较全面的介绍,并探讨了凝胶聚合物电解质的应用前景。     

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.     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

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.……     

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.     

Synthesis of Alumina-Zirconia Nanocomposites by Solgel Process

Al₂O₃-ZrO₂ nanocomposites were developed starting with the solgel process. Composite alumina-zirconia nanopowders were synthesized from metallorganic precursors (Aluminium secondary butoxide and zirconium Iso propoxide) using the solgel process. The parameters affecting the synthesis—solvent, concentration of precursor, R/H ratio (i.e., dilution of water in solvent)—were varied as also the temperature and pH. BET and TEM were used to measure nanosize. Diffuse reflectance spectroscopy and also qualitative optical absorption led to identical particle size estimate. The variation of process parameters was used to study the effect and interdependence of process parameters. Artificial Neural Networks was used to rigorously analyze the process. Although this led to confirmation of interdependence of parameters, the presence of a single overwhelming solvent variable was also established. Then the optimal process was used to synthesize more nanopowder. To produce bulk nanocomposite the nanopowders were sintered by varying the temperature and time period. The sintered lithoids were probed with a vickers hardness tester to measure elastic modulus, hardness, and fracture toughness. The results showed high elastic modulus, modest hardness, and very high fracture toughness.     

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.……     

Friction Stir Processing Strategies for Uniform Distribution of Reinforcement in a Surface Composite

Friction stir processing (FSP) is an important technique for preparing surface composites. Fabricating defect-free surface composites with uniform particle distribution by FSP is a challenging task. In this study, silicon carbide particles reinforced AA5083 alloy surface composites was fabricated using different FSP strategies including variation in process parameters, dual-tool processing and tool offset overlapping. Material flow of the processed material with reinforcement particles demonstrated that the distribution of particles was influenced by the stirring action of the probe as well as the extrusion of the plasticized material due to the movement of the tool. Process parameters, particularly rotational speed, showed a dominant influence on the distribution of silicon carbide particles.