缓蚀剂对提高铝箔比容的影响

研究高纯铝箔在盐酸直流电侵蚀时缓蚀剂对腐蚀箔比电容的影响,扩孔使用缓蚀剂后,孔密度增加,孔径减小,失重减小,中高压电容器铝箔的比电容约提高12％。     

电解电容器用铝箔腐蚀液中葡萄糖的作用

研究了葡萄糖对铝箔交流腐蚀扩面的影响,采用循环伏安法对电容结果进行表征。发现葡萄糖的加入,有助于铝箔的腐蚀和扩孔,比电容有较大幅度的提高,并且葡萄糖对低纯度铝箔影响更大,1.0g/L葡萄糖导致低纯铝箔(99.2%)比容约提高30%,高纯铝箔(99.99%)提高约10%。     

国内铝电解电容器用阳极箔的研究进展

简述了铝电解电容器用阳极箔的国内研究现状,介绍了阳极箔的制备方法.对铝箔的预处理、扩孔液中添加金属离子以及缓蚀剂如何提高阳极箔的比电容进行了综述.     

化学镀锌对阳极铝箔腐蚀扩面的影响

通过化学镀法在铝箔表面施镀微量的锌元素,对镀锌后的阳极铝箔腐蚀扩面的过程及机理进行研究。结果表明,化学镀锌后,铝箔在腐蚀过程中其表面形成Zn-Al微电池效应,促进了铝箔的电化学腐蚀,改善了隧道孔形貌,使铝箔的隧道孔分散均匀,孔径减小,且密度明显增大,进而增大了铝箔的比电容。     

金属离子对电极箔扩面腐蚀影响的研究进展

对近年来微量金属离子在铝电解电容器用电极箔扩面腐蚀工艺的最新研究成果进行了总结,在铝箔腐蚀过程中,金属离子能与铝形成电偶腐蚀,在铝箔表面指引点蚀生长,使铝箔的腐蚀电位负移,孔密度增大,并孔减少,比电容增大。讨论了它们各自的技术优势和短板,展望了今后微量金属离子对电极箔扩面腐蚀技术在性能及机理研究方面的趋势。     

甘油浓度对高压腐蚀箔的性能影响

甘油作为缓蚀剂对铝电解电容器阳极腐蚀铝箔孔洞的生长有显著的抑制效果,随甘油浓度增加,孔洞长度和数目减少,孔洞均匀性明显改善,腐蚀箔的比电容先增大后减少。当甘油浓度为0.5 g/L时腐蚀箔的比电容达到最大值0.776μF/cm2。     

铝集流体表面处理对锂离子电池性能的影响

以铝箔为基材,在磷酸–硫酸混合溶液中采用直流阳极氧化法进行表面处理,使铝箔表面形成多孔氧化铝结构。采用粘附力测试、扫描电镜、循环伏安、电化学阻抗谱、恒流充放电等方法,对铝箔表面结构及以其作为正极集流体的锂离子电池充放电性能进行考察。结果表明,经过阳极氧化处理的铝箔表面形成孔径为1~5μm的多孔氧化铝层,使活性材料的粘附力提高了23%,在1 mol/L LiP F6的碳酸甲乙酯和碳酸乙烯酯电解液体系中的耐腐蚀性能得到明显提升。未处理铝箔的腐蚀电流密度峰值为0.267 mA/cm2,阳极氧化处理后降至0.022 m A/cm2。经过200次充放电循环后,0.5 C、1 C和5 C倍率下采用经阳极氧化处理铝箔的锂离子电池比容量比采用未处理铝箔的电池比容量分别高2.85%、4.42%和10.56%。     

竹质中孔活性炭在双电层电容器中的应用研究

以毛竹废料为原料,采用磷酸活化法制备了具有较高比表面积又含有大量中孔的活性炭,根据77K氮气吸附等温线对其结构性质进行了表征,并以产品活性炭为电极材料组装双电层电容器,对其充放电性能进行了测试.实验结果表明:产品活性炭比表面积为1567m2/g,中孔体积为0.67cm3/g,中孔比例达47.18%.以该活性炭为电极材料的双电层电容器具有良好的充放电性能,既能以小电流长时间慢速充放电,又能以大电流短时间快速充放电,电极比电容达170F/g.在1000mA/g电流密度下,活性炭放电比电容为131F/g,比电容保持率为77%,功率特性良好.     

应用灰色系统理论预测硫酸盐侵蚀环境下混凝土的强度劣化规律及服役寿命

制备了水胶比分别为0.32,0.40和0.48的纯水泥混凝土试件,水胶比0.32,粉煤灰掺量10%或20%的粉煤灰混凝土试件,矿粉掺量15%或30%的矿粉混凝土试件,粉煤灰和早强剂掺量分别为20%和1%的含早强剂粉煤灰混凝土试件,及粉煤灰和矿粉掺量分别为15%和15%的混凝土试件.将混凝土试件暴露于干湿循环-硫酸盐加速侵蚀环境中,测试试件抗压强度的演变规律.采用灰色关联理论研究了硫酸盐浓度、水胶比、矿物掺合料及外加剂等因素对混凝土抗压强度的影响.通过建立多元灰预测模型分析了硫酸盐侵蚀环境下混凝土的强度劣化规律及服役寿命.结果表明:强度影响因素的灰色关联度由大到小的排序为;水胶比,硫酸盐浓度,测试龄期,粉煤灰掺量,矿粉掺量,早强剂掺量.多元灰预测模型呈现出较高的精度以预测硫酸盐侵蚀环境下混凝土的强度劣化规律和服役寿命.     

活性炭表面改性对其比电容及储能机理的影响

采用熔融Na2S对活性炭表面进行改性，通过循环伏安测试了活性炭的比电容，并通过FT-IR, BET, EIS和电泳实验分析了比电容变化的原因及其储能机理。研究发现，以10%的硫酸钠溶液为电解质，活性炭经Na2S 1000℃热处理1 h后的比电容由44.6 F/g提升至80.8 F/g，所增加的比电容主要来自于双电层电容，部分来自于氧化还原赝电容(占总电容的5.6%)。通过向电解质溶液中添加37 mmol/L的FeCl3，比电容提高至103 F/g (赝电容占12.6%)，但并不稳定，后期有下降的趋势。如果向电解质溶液添加30 mmol/L的K3[Fe(CN)6]，则比电容提升到了126 F/g，并且非常稳定、甚至有继续缓慢增加的趋势。活性炭经Na2S热处理后，储能机理由单纯的双电层物理储能变为双电层物理&化学储能+氧化还原赝电容储能。     

Understanding the effects of electrode meso-macropore structure and solvent polarity on electric double layer capacitors based on a continuum model

The structures of electrode meso-macropore and the solvent polarity are the crucial factors dominating the performance of the electric double layer capacitors (EDLCs), but their impacts are usually tangled and difficult to decouple and quantitate. Here the effects of electrode meso-macropore structure and solvent polarity on the specific capacitance of an EDLC are quantitatively investigated using a steady-state continuum model. The simulation results indicate the specific capacitances are significantly affected by the meso-macropore surface structure. The specific capacitances significantly decrease for both convex surface structures but obviously increase for both concave surface structures, with the increase of curvature radius from 1 to 20 nm. As for solvents, the polar solvent with high saturated dielectric permittivity improves the capacitance performance. Moreover, the electrode meso-macropore structure is of more concern compared with solvent polarity when aiming at enhancing the specific capacitance. These results provide fundamentals for the rational design of porous electrodes and polar electrolytes for EDLCs.     

Specific Volume Diagrams for Ceramic Processing

Graphical procedures are presented for analyzing the volume-weight relations in ceramic particulate systems encountered in processing. The procedures emphasize the advantages of working with specific volume rather than density. By using the concept of partial specific volumes, the expected variations in specific volume with composition for many special cases are readily deduced. Comparing experimental and theoretical variations gives meaningful insights into the space-filling characteristics of real systems.     

Selection of barrier materials from molecular structure

A prediction technique for gas permeability from polymer structure has been developed on the basis of a specific free volume diffusion theory. In this theory, the free volume available per unit mass in a polymer structure controls the rate of gas diffusion and, hence, its rate of permeation. The smaller this specific free volume is, the more difficult the gas diffusion and, thus, the better its barrier to gases becomes. Specifically, the theory predicts a linear relationship between log (permeability) and (?1/specific volume). A number of existing polymers covering six orders of magnitude in CO₂ permeability and O₂ permeability were found to follow this correlation. The specific free volume in a polymer was obtained from group contribution calculations. As a result, the gas permeabilities become predictable from the specific volume in a polymer which, in turn, varies with its molecular structure. The advent of this specific free volume theory for gas permeation simplifies greatly the selection of barrier materials for packaging applications. For a given barrier application, a critical specific free volume is first defined from its gas barrier requirement. The polymer structures having specific free volumes smaller than the critical value are then identified. These are the polymers that would have the necessary barrier performance. By this theory, molecular structures, with string polar-to-polar interactions and hydrogen-bonding forces are found to be good barriers to CO₂ and O₂.     

Natural Graphites Used as Additions and Their Effect on the Performance of Carbon-Containing Refractories

Natural graphites as additions to periclase-carbon refractory materials are considered. The effect of ash components and natural graphites with different specific surface on the oxidizability, mechanical strength, and slag resistance of the refractory material are studied. Low-ash natural graphites with low specific surface are recommended for production of periclase-carbon refractories.     

应用WCA微扰理论推算非极性液体比热容的新方法

本文首次将统计热力学的Ｗｅｅｋｓ－Ｃｈａｎｄｌｅｒ－Ａｎｄｅｒｓｏｎ（简称ＷＣＡ）微扰理论应用于非极性液体定容比热容和定压比热容的推算，用一些液体的ｐ－ｖ－Ｔ实验数据拟合了理论中所用ＬＪ势能函数的势能参数，并提出一个通用关联式。本文方法具有通用性，在编制的计算程序中只需输入物质的临界温度、临界比容、偏心因子等就能算出相应的比热容，工程应用十分方便。     

NOTES ON TERRA COTTA GLAZE CONSISTENCY1

Some of the difficulties encountered in applying glaze to terra cotta are discussed. The use of a hydrometer to test glazes is misleading as a hydrometer supplies gravity indication only in true solutions and glazes are not true solutions; furthermore the viscosity of a glaze may obscure the real specific gravity. It is suggested that in order to Control a glaze it should first be made to a desirable specific gravity and then the desired viscosity at that gravity be ascertained by experiment. A viscosimeter and specific gravity bottle are suggested for this purpose. The effect of change of alkalinity and of bacteria together with the control of glaze wastage are also discussed.     

活化温度对酚醛基活性炭纤维的孔结构和电化学性能的影响

从酚醛纤维出发,经过炭化和KOH活化制备了酚醛基活性炭纤维（PACF）,并对不同温度下活化样品的比表面积、孔结构以及所制备的双电层电容器（EDLC）的电化学性能之间的关系进行了探讨。氮气（77K）吸附法测定PACF活性炭纤维的孔结构和比表面积;采用循环伏安、交流阻抗、恒流充放电等测试对超级电容器的电化学性能进行了测试。结果表明：900℃是KOH活化酚醛纤维制备用于EDLC电极材料的最佳活化温度,该温度下活化样品具有最佳的循环性,稳定性和较小的内阻,比表面积为2311m^2·g^-1和比电容264．IF·g^-1（充放电电流为1000mA·g^-1）。PACF系列样品均呈现出典型的微孔炭的特征,不同活化温度下制备的PACF,虽然表现出不同的比表面积和比电容,但是其整体孔径分布范围基本相同,都在0.5nm～3．0nm之间。随活化温度的升高,样品的电容性能和功率特性越来越好,内阻也随活化温度的升高而降低。     

A stochastic approach to the analysis of chemically reacting systems—I. The role of internal fluctuations

The present work analyses the role of fluctuations for a class of reacting systems involving one or more than one variable using the expansion method. General equations are formulated and illustrated by considering specific examples. The analysis indicates that fluctuations cannot always be ignored and that their monitoring can lead to additional information regarding the system. The specific cases analysed are discussed.     

On the Jones-Wilkins-Lee equation of state for high explosive products

The Jones-Wilkins-Lee (JWL) model is a widely used Equation Of State (EOS) in the literature to model high explosive products. It is based on exponentially decaying isentropes in the pressure-volume diagram, completed by an additional term meant to recover an ideal-gas behavior for large expansions where exponential terms are negligible. A step-by-step analysis of the EOS is proposed. Starting from the main isentrope, the constant Grüneisen, and constant isochoric heat capacity, the JWL expressions of pressure, temperature, sound speed, specific internal energy, specific entropy and specific enthalpy are derived. For a specific set of JWL parameters meant to model HMX products, various thermodynamic fields are investigated in pressure–volume and temperature–volume planes. The positivity of pressure and temperature, the convexity, the thermodynamic stability, and the monotonicity along an Hugoniot are investigated in order to characterize the JWL domain of validity. For each of these constraints, different regions of validity are found. Besides presenting a study of the JWL model and its limits, this work also provides a standalone presentation and derivation containing the necessary materials for the understanding and for the use of the JWL EOS in reactive hydrodynamic simulations of condensed phase explosives.     

具有高比表面积的稻壳灰的制备及其化学活性的研究

Preparation of rice husk ash with high specific surface area and chemical reactivity of the product are reported in this paper. The amorphous rice husk ash with high specific surface area of 311 m^2.g^-1 was produced by heating acid treated rice husk at 700~C for 4 h. The isotherms of rice husk ash are similar in shape to type Ⅱ of Brunaner‘s classification with mesopores being predominant. The rice husk ash has a high chemical reactivity, especially that pretreated with acid. This chemical reactivity depends on ashing temperature and pretreatment conditions. There is an exponential relation between the specific surface area of rice husk ash and the change in the conductivity of saturated Ca(OH)2 solution with rice husk ash, from which the specific surface area can be known according to the conductivity change.