聚合物结构对凝胶聚合物电解质热稳定性的影响

为探索聚合物结构对相应凝胶电解质稳定性，特别是中低温热稳定性的影响，本研究对于丙烯碳酸酯／高氯酸锂分别与PMMA、PMA、丁腈胶以及PVDF制备的凝胶电解质，进行了热失重和等温热失重的研究。结果表明，由PMMA和PMA形成的凝胶电解质的热稳定性都较好，优于丁腈胶为基材的体系。由PVDF形成的凝胶电解质由于不断晶化，导致对电解液的保持能力欠佳，用添加PMMA的方法改善了其热稳定性。     

纳米SiO2微球在PMMA凝胶聚合物电解质中的尺寸效应及其在全固态电致变色器件中的应用

本文采用St?ber法制备了不同粒径纳米SiO_2微球,将其加入到聚甲基丙烯酸甲酯(PMMA)基凝胶聚合物电解质中,研究了纳米SiO_2的尺寸效应及其对全固态电致变色器件性能的影响。研究发现,正硅酸乙酯和乙醇的体积比影响所得纳米SiO_2微球粒径大小,乙醇所占体积比例越大,制备的纳米SiO_2微球粒径越小。在PMMA基凝胶聚合物电解质中,当纳米SiO_2微球用量相同时,电解质的电化学窗口随着纳米SiO_2微球粒径的减小先增大后减小,离子电导率随纳米SiO_2微球粒径的增大而增大,在纳米SiO_2微球粒径为150 nm时电化学窗口达到最大,离子电导率的增速也变得不明显。当粒径为150 nm的纳米SiO_2微球含量为7wt%时,PMMA凝胶电解质的电化学窗口为4.8 V,电导率为1.13 mS/cm。以该电解质组装结构为:导电玻璃(ITO)‖SiO_2/碳酸丙烯脂(PC)-LiClO_4/PMMA‖金属-超分子聚合物‖ITO的透射式全固态电致变色器件,所得器件可在淡绿色和深蓝色之间变色,对比度高达60.1%,且器件的稳定性得以明显提高。     

聚醚侧链型聚硅氧烷对含氟聚合物凝胶锂离子电解质膜性能的影响

通过浸没沉淀相转化法制备了具有类似孔结构的聚醚侧链型聚硅氧烷(PDMS-g-(PPO-PEO))改性的聚偏氟乙烯(PVDF)和聚偏氟乙烯-六氟丙烯(PVDF-HFP)多孔骨架,经电解液活化后得到凝胶电解质膜,研究了PDMS-g-(PPO-PEO)对含氟聚合物凝胶电解质膜性能的影响。由改性PVDF和PVDF-HFP骨架被电解液活化制备的聚合物凝胶电解质膜,离子电导率分别达到2.2×10-3和1.7×10-3S/cm,综合分析凝胶电解质膜中电解液稳定性和膜的电化学性能发现,PDMS-g-(PPO-PEO)对PVDF骨架的改性效果明显优于PVDF-HFP骨架,共混改性后PVDF可代替PVDF-HFP作为隔膜作为锂离子电池凝胶电解质膜。     

P(VdF-HFP)-PMMA聚合物电解质的研究

采用共混法制备了P(VdF-HFP)-PMMA聚合物电解质，PMMA与电解液有更好的相溶性。含PMMA45%的聚合物膜，20℃时电解液吸附量为260%，离子导电率为0.95mS/cm。以该膜和1mol/L LiPF6(EC/EMC)为电解质，LiCoO2为正极，碳纤维为负极的聚合物锂离子电池具有较小的界面电阻和电荷转移电阻，良好的循环稳定性（1/3C倍率循环35次，95%初始放电容量），和良好的倍率性能（2C倍率，73%初始放电容量）。     

PMMA基凝胶聚合物电解质研究进展

综述了聚甲基丙烯酸甲酯(PMMA)基凝胶聚合物电解质(GPE)的研究进展,提出了PMMA基凝胶电解质目前主要存在的问题,着重讨论了采用共聚共混、交联和添加无机填料等对PMMA进行改性的方法,以及PMMA基GPE的三种制备方法.     

锂盐对交联PPCMA聚合物电解质性能的影响

以二氧化碳(CO2)、环氧丙烷(PO)和马来酸酐(MA)三元共聚反应合成聚甲基乙撑碳酸酯马来酸酐(PPCMA),再经交联和浸渍电解液活化,制备了性能优良的PPCMA凝胶聚合物电解质。研究发现,随着交联剂过氧化二异丙苯(DCP)的增加,交联PPCMA的玻璃化转变温度升高,热稳定性增强,PPCMA凝胶聚合物电解质的离子电导率先增加后减小,当DCP用量为1.2%、LiClO4浓度为1.1mol/dm3、LiBOB质量分数为1.3%时,PPCMA凝胶聚合物电解质的室温离子电导率达到最大值1.47×10-2S/cm。Li/PPCMAGPE/LiNi1/3Co1/3Mn1/3O2聚合物锂离子电池的首次放电容量为115.3mAh/g。     

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。     

PEO基聚合物电解质

聚氧化乙烯（PEO）基电解质是研究最早的聚合物电解质体系，它在电池生产中已得到应用。PEO基聚合物电解质主要分为聚合物/盐型和凝胶型两大类，凝胶型聚合物电解质因具有较高的电导率而被认为是固态锂离子电池最有应用前景的临时性解质体系。对两种类型的聚合物电解质的研究进展作了较为详细的论述，在此基础上分析了PEO基聚合物电解质中离子的传输机理。PEO基聚合物电解质中离子的运动能力与链的结构。离子浓度，温度，增塑剂等因素有关。     

PVDF/PMMA/PEG型聚合物隔膜的制备

为提高锂离子电池聚偏氟乙烯(PVDF)基聚合物隔膜对电解液体系的亲和性和导电性,引入聚甲基丙烯酸甲酯(PMMA)与聚偏氟乙烯(PVDF)进行共混,并添加有机增塑剂聚乙二醇PEG-400对PVDF基聚合物隔膜进行改性研究。采用先干法后湿法的相转化方法制备PVDF/PMMA/PEG型聚合物隔膜。通过对制备的聚合物隔膜的孔隙率、吸液率、微观形貌和电化学性能的分析研究,确定制膜的最佳工艺条件为聚合物占溶剂质量百分比为8%,PVDF∶PMMA=7∶3,增塑剂含量为30%,非溶剂含量为3%,反应温度为45℃,在此最佳工艺条件下制备的PVDF/PMMA/PEG隔膜的离子电导率可达2.848 m S/cm,对电解液体系的亲和性和导电性得到显著提高。     

P(MMA-MAh)凝胶聚合物电解质的制备及其性能

以自制的甲基丙烯酸甲酯与马来酸酐的共聚物(P(MMA-MAh))为基体,丙烯碳酸酯(PC)为增塑剂,LiClO4为锂盐,制备成凝胶聚合物电解质(GPE);采用交流阻抗法、差示扫描量热法(DSC)、热失重分析(TGA)对此GPE的电性能及热性能作了研究,并且研究了不同配比及温度对其离子电导率的影响.结果表明,以P(MMA-MAh)为基体的GPE与PMMA基GPE相比,共聚型P(MMA-MAh)的凝胶体系较好的成膜性和热稳定性;当共聚物含量为60%(质量分数)时,凝胶体系的玻璃化转变温度为27.28℃,质量损失为5%时热分解温度为145℃;当共聚物含量为45%(质量分数)时,凝胶聚合物电解质的综合性能较好;且共聚物P(MMA-MAh)基GPE的离子电导率与温度的关系服从Arrhenius方程.     

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...     

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.     

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.……     

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.     

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.     

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.