Polyvinylidene fluoride/polystyrene hybrid fibers with high ionic conductivity and enhanced mechanical strength as lithium-ion battery separators

Journal of Solid State Electrochemistry - Ionic conductivity is an important separator parameter influencing the cycle life and rate capability of lithium-ion batteries (LIBs). To improve the ionic...     

Second-order nonlinearities of lead borate glasses poled with different electrodes

The second-order nonlinearities in thermally poled lead borate glasses were studied. After poling with different electrodes, both bulk and near surface second-order nonlinearities were obtained. The second harmonic generation signal from near surface effect was two orders of magnitude larger than the bulk effect. By simulating the poling process with a multiple carrier model, we concluded that the bulk second-order nonlinearity was caused by the deficiency of Pb²⁺ in a thick layer after poling, and the near surface second-order nonlinearity was caused by the depletion of H⁺ in a thin layer when H⁺ injection from the atmosphere was blocked.     

热点问题情报过滤模型与算法

针对热点问题跨越时间长以及含重复情报、过时情报和无实用价值信息量大等问题,提出了一种新的热点问题情报获取模型与分级过滤算法,以解决情报的去粗取精、去伪存真问题.首先将无序关联情报结构化,然后采用SVM(space vector model)方法,根据热点问题情报的特殊性,提出了新的特征选择方法,在特征向量的相似性计算中引入去除重复和过时情报的判别参数,达到优化情报的目的.实验结果表明,过滤算法除去原始情报库中的无关情报、重复情报和过时情报后剩余情报数约为原始情报数的59%.     

幂次中心势阱中粒子能谱规律的分析

分析了幂次中心势阱中粒子的能谱，讨论了粒子能谱形状随幂次变化的规律     

A novel (3,4,10)‐connected three‐dimensional hydrogen‐bonded supramolecular network containing a cyclic water hexamer

The title compound, 4,4′‐(1,1,1,3,3,3‐hexafluoroisopropylidene)diphthalic acid hexahydrate, C₁₉H₁₀F₆O₈·6H₂O, crystallizes in the centrosymmetric space group Pbcn, with half of the diphthalic acid residue and three water molecules in the asymmetric unit. The organic molecule is located on a crystallographic twofold axis. In the solid, cyclic water hexamers in chair conformations have crystallographically imposed inversion symmetry. Strong O—H...O hydrogen bonds between the hexamers and organic molecules result in a unique three‐dimensional supramolecular network [O...O = 2.554 (2)–2.913 (2) Å]. This compound represents the first example of a (3,4,4,10)‐connected four‐nodal supramolecular topology with the Schläfli symbol (4³.5.6.7)₂(4³.5².7)₂(4³)₂(4⁶.5⁶.6².7⁸.8¹⁴.9⁹).     

SH15树脂吸附胞二磷胆碱的热力学及动力学研究

静态条件下,研究了SH15树脂吸附水溶液中胞二磷胆碱(CDPC)的热力学和动力学特性.测定了不同温度下,热力学性质的变化.实验结果表明,SH15树脂对CDPC吸附平衡数据符合Langmmuir吸附等温方程,吸附过程为自发的物理吸附过程.考察了温度、溶液浓度、树脂粒径和搅拌速率对吸附过程的影响.运用动边界模型(MBM)描述了SH15树脂吸附CDPC的动力学过程,确定在实验条件范围内,SH15树脂吸附CDPC的吸附速度受颗粒扩散控制,并计算出吸附过程的表观活化能为9.73kJ/mol,反应级数为0.47,速率常数为0.0744,并推导出CDPC:在SH15树脂上的动力学总方程.     

Two new secoiridoid glucosides from Syringa velutina Kom

Chemical investigation of Syringa velutina Kom. led to the isolation of two new secoiridoid glucosides. Their structures were identified as 6'-0-(6, 7-dihyrofoliamenthoyl)-8-epi-kingisidic acid (syrveoside A, 1) and 6'-O-menthiafoloyl-8-epi-kingisidic acid (syrveoside B, 2) on the basis of chemical and physicochemical evidence.     

A General Theoretical Model of Enthalpy‐Entropy Compensation

Enthalpy‐entropy compensation remains a mystery in chemistry and biophysics. Recent study suggested that the solvent reorganization might constitute the physical origin of the compensation, which was unfortunately not widely applicable because compensation was also observed in solid phase reactions. In this study, a general theoretical model based upon strict mathematical deduction was presented, which indicated that the redistribution of the distinguishable subspecies might be the physical origin of the enthalpy‐entropy compensation in complex systems. As examples, the enthalpy‐entropy compensations in solvation and surface adsorption were discussed.