大型软包锂离子电池的热物性实验研究

针对大型软包锂离子电池热物性参数的测定问题,提出适用于该型电池的热参数表征方法. 基于准稳态导热原理,建立电池的传热理论模型. 开展实验研究电池的比定压热容和导热系数与温度的依变关系,分析热损对测试结果的影响,对测试方法的有效性进行验证. 结果表明,电池比定压热容随着温度的升高而线性增大,导热系数受温度的影响较小. 在900 s内可以测得电池热参数在10~60 °C下的变化状况,实验验证结果显示测算精度高于92.3%,具有测算周期短、准确度高和测试灵活等优势.     

Structural and transport effects of doping perfluorosulfonic acid polymers with the heteropoly acids, H3PW12O40 or H4SiW12O40

A perfluorosulfonic acid (PFSA) polymer with pendant side chain -O(CF₂)₄SO₃H was doped with the heteropoly acids (HPAs), H₃PW₁₂O₄₀ and H₄SiW₁₂O₄₀. Infrared spectroscopy revealed a strong interaction between the HPA and the PFSA ionomer. Modes associated with the peripheral bonds of the HPA were shifted to lower wave numbers when doped into PFSA membranes. Small-angle X-ray scattering (SAXS) measurements showed the presence of large crystallites of HPA in the membrane with d spacings of ca. 10 Å, close to the lattice spacing observed in bulk HPA crystals. Under wet conditions the HPA was more dispersed and constrained the size of the sulfonic acid clusters to 20 Å at a 5 wt% HPA doping level, the same as in the vacuum treated ionomer samples. Under conditions of minimum hydration the HPA decreased the E_a for the self-diffusion of water from 27 to 15 kJ mol⁻¹. The reverse trend was seen under 100% RH conditions. Proton conductivity measurements showed improved proton conductivity of the HPA doped PFSAs at a constant dew point of 80 °C for all temperatures up to 120 °C and at all relative hummidities up to 80%. The activation energy for proton conduction generally was lower than for the undoped materials at RH ≤80%. Significantly the E_a was 1/2 that of the undoped material at RHs of 40 and 60%. A practical proton conductivity of 113 mS cm⁻¹ was observed at 100 °C and 80% RH.     

New catalyst systems for the polymerization of acetylene

The catalytic activities of WCI₆Ph₄Sn, MoCl₅Ph₄Sn and tetrabenzyltitanium were examined in the polymerization of acetylene. The structure, morphology and electrical conductivity of the doped and non doped polyacetylene were also studied.     

水平钢化炉中传动辊内的温度分析

对水平钢化炉内传动辊的温度场进行了数值模拟。在研究玻璃加热过程时，传动辊释放出的辐射热是个非常重要的因素，其大小与传动辊的温度有关，影响着钢化玻璃的质量。传动辊温度随加热时间而改变，在计算玻璃板温度时，必须与传动辊的温度场耦合求解。     

Time dependences of conduction and self‐heating in acetylene carbon black‐filled high‐density polyethylene composites

The time dependences of electrical conduction and self‐heating behaviors in high‐density polyethylene filled with acetylene carbon black of 0.082 in volume fraction are studied in relation to voltage and ambient temperature. The characteristic decay current constant τ_i, and the exponential growth time constant for self‐heating τ_g are determined for the samples under voltages U above the critical value U_c for the onset of self‐heating. The influences of voltage and ambient temperature on τ_i and τ_g as well as the amplitude of the low‐resistance to high‐resistance switching are discussed on the basis of the random resistor network (RRN) model and the relationship between U_c and the intrinsic resistivity. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1124–1131, 2006     

Sharkskin mechanism of high‐impact polystyrene (HIPS) and rheological behavior of HIPS/TiO2 composites

The rheological behaviors of high‐impact polystyrene (HIPS) and HIPS/TiO₂ composites were investigated by use of a rheometer in the present article. HIPS exhibited a constant critical stress of the sharkskin in various temperatures, and the analysis indicated that the mechanism of sharkskin of HIPS was wall–slip and its special temperature dependency was determined by weak wall–melt adsorption. The experimental results also showed that the introduction of TiO₂ into HIPS only slightly influenced the apparent viscosity (η_a) of the composites. Moreover, TiO₂ exhibited an unusual effect on the non‐Newtonian index of the composites at high shear rate. Both phenomena indicated the increase of inner free volume induced by TiO₂ in molecularly rigid HIPS. Moreover, it was noteworthy that a featured stress could be used to label the dispersion of TiO₂ in the HIPS matrix, and the numeric affinity of this featured stress and the critical stress of sharkskin revealed that both processes were relevant to the same molecular relaxation. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 802–807, 2005     

导电性塑料的研究进展

本文介绍了导电性塑料的发现、分类、品种、应用、研究重点和发展前景。对导电性高聚物的一般合成方法如链聚合法和分步聚合法、特殊的合成方法如光化学聚合进行了总结，并对共轭高聚物的导电机理作了简单的评述。     

转化乳剂的离子电导和光电导研究

本文研究了ＡｇＢｒＣｌ转化乳剂的离子电导和光电导。随着乳剂中溴含量的增高，其离子电导也随之升高，而光电子寿命则降低。ＡｇＢｒＣｌ乳剂的离子电导主要取决于其组成；ＡｇＢｒＣｌ转化乳剂的光电子寿命主要受隙间银子浓度的影响，隙间银离子浓度越大，光电子寿命越短。     

Combustion characteristics and flame stability at the microscale: a CFD study of premixed methane/air mixtures

A two-dimensional elliptic, computational fluid dynamics (CFD) model of a microburner is solved to study the effects of microburner dimensions, conductivity and thickness of wall materials, external heat losses, and operating conditions on combustion characteristics and flame stability. We have found that the wall conductivity and thickness are very important as they determine the upstream heat transfer, which is necessary for flame ignition and stability, and the material's integrity by controlling the existence of hot spots. Two modes of flame extinction occur: a spatially global type for large wall thermal conductivities and/or low flow velocities and blowout. It is shown that there exists a narrow range of flow velocities that permit sustained combustion within a microburner. Large transverse and axial gradients are observed even at these small scales under certain conditions. Periodic oscillations are observed near extinction in cases of high heat loss. Engineering maps that delineate flame stability, extinction, and blowout are constructed. Design recommendations are finally made.     

基于GTST-MLD的复杂网络风险评估方法

针对复杂信息系统复杂程度高、互影响性与互依赖性强,现有风险评估方法难以适应大规模网络安全风险评估与应用实践的需要的问题,研究了基于GTST-MLD的适合复杂信息系统的风险要素分析方法和整体风险评估方法,包括研究事故互依赖关系模型,进行风险要素建模以及风险传导分析,以提高针对复杂信息系统的风险评估能力和分析水平。结果证明,模型对复杂信息系统安全特性的目标、功能、结构、行为等因素予以综合,实现在更高的系统功能层面上对系统安全性的分析研究,为复杂信息系统的量化风险评估提供了可靠的量化分析手段。