水在高温硫化硅橡胶中的扩散特性研究

水分侵入是造成复合绝缘子高温硫化硅橡胶伞裙、护套材料老化的主要因素之一。为了获得能够准确描述水分子在硅橡胶中扩散的扩散模型和扩散特性,使用固体核磁共振(nuclear magnetic resonance,NMR)技术,分析了水分子在硅橡胶中的存在状态;并通过称重法试验,获得了水分子在硅橡胶中扩散时硅橡胶的增重曲线。研究表明,水分子在硅橡胶中存在"自由态"和"结合态"两种不同的状态。固体核磁共振和称重法的试验结果都表明,水分子在硅橡胶中的扩散过程符合Langmuir扩散模型,而不符合经典的Fick扩散模型。同时研究了水分子扩散过程的影响因素,结果发现:自由态水分子的含量随温度的升高而增加,结合态水分子的含量随温度的升高而降低,且温度对扩散系数的影响符合经典的Arrhenius方程;硅橡胶中的氢氧化铝(ATH)填料含量的增加会导致结合态水分子含量的增加,但ATH含量对自由态水分子含量的影响不显著。     

基于共存理论的转炉脱磷热力学分析

为了定量研究温度、炉渣成分、钢液成分对转炉磷分配比和平衡磷含量的影响,基于共存理论建立转炉炼钢六元渣系的组元活度计算模型和磷分配比L_P计算模型,将磷分配比模型计算结果与转炉炼钢实测磷分配比进行对比,发现两者吻合较好。定量计算结果表明,当炉渣碱度为3.8时,钢液温度从1 640升到1 680 ℃,平衡磷质量分数从0.011 5%增加至0.019 8%。同时定量计算了炉渣碱度及氧化铁含量变化对平衡磷含量的影响,但实际炉渣控制需要考虑炉渣黏度、铁损及炉衬侵蚀。转炉吹炼终点钢中元素含量数量级较小,计算表明终点成分变化对磷活度系数的影响不大,各元素对脱磷的影响主要体现在冶炼初期和过程。     

“动态超分子”假说预测烷烃吸收CO2相平衡

采用“动态超分子假说”对烷烃吸收CO₂相平衡进行了研究,并结合最小二乘法和试算对烷烃数据进行拟合,得到相关参数,拟合值和文献实验值的线性相关度均大于0.95,符合良好。研究表明,烷烃分子之间形成的同种“动态超分子”对吸收过程影响较大,远远大于CO₂同种超分子和溶剂与CO₂之间形成的异种超分子,而且其随着烷烃碳链增加,“动态超分子”形成概率和稳定性均降低,吸收能力逐渐增强。文中还研究了模型参数对拟合结果的影响,及其最佳取值范围。     

Searching proper oligothiophene segment as centre donor moiety for isoindigo-based small molecular photovoltaic materials

Systematic studies on a family of photovoltaic molecules are important for fundamentally understanding the basic principles and the key structural factors that govern their photovoltaic performance. In this work, a series of D²-A-D¹-A-D² type small molecules with isoindigo as acceptor (A), oligothiophene as donor (D¹), and 5-hexyl thiophene as D² were designed, synthesized and studied. The number of thiophene unit in oligothiophene segment is systematically varied from 0 to 4. It has been found this structural parameter have significant influence on their phase transition behaviours, light absorption properties, frontier orbital energy levels, molecular packing structures in both neat and blending films with [6,6]-phenyl-C₆₁-butyric acid methyl ester (PC₆₁BM), charge mobility, phase separation morphology, and as well as photovoltaic performances. The compounds bearing odd number of thiophene unit displayed much better photovoltaic performance than those having even number, while the best performance was given by that having terthiophene as D¹ unit.     

非核苷类抗乙肝病毒小分子抑制剂的研究进展

慢性乙型肝炎病毒(HBV)感染是许多肝疾病,如肝炎、肝硬化和肝癌的病因,至今仍是影响人类健康的全球性问题。当前临床用药主要包括免疫调节剂和能抑制逆转录酶活性的核苷类似物,但免疫调节剂的副作用和核苷类似物的耐受性使得慢性乙型肝炎的临床治疗仍然面临着巨大的挑战,而非核苷类抗HBV药物的研究为这一现状的改变提供了很大机会。综述了近年来报道的非核苷类抗HBV小分子抑制剂,重点对其化学结构、抗HBV活性和构效关系进行了总结。     

DNA molecule stretching through thermo-electrophoresis and thermal convection in a heated converging-diverging microchannel

A novel DNA molecule stretching technique is developed and tested herein. Through a heated converging-diverging microchannel, thermal convection and thermophoresis induced by regional heating are shown to significantly elongate single DNA molecules; they are visualized via a confocal laser scanning microscopy. In addition, electrophoretic stretching is also implemented to examine the hybrid effect on the conformation and dynamics of single DNA molecules. The physical properties of the DNA molecules are secured via experimental measurements.     

低能电子冲击下,环己烷的离解

使用自行设计组装调试的离解谱仪,研究了环己烷(C_6H_(12))蒸汽样品在低能电子冲击下的离解产物。实验表明出现的主要产物是质量数为56,68及84的离子。     

基于原子能级的多电子多原子分子的能量表达式

基于约化密度矩阵理论，导出以与标度核电荷相应的二电子原子的能级为参数的多电子多原子分子的能量表达式．提出电子对平均几率函数表达式。以双原子分子的计算为例，证明了这方法的有效、可靠与简便．