Structural,Spectroscopic and Reactivity Studies on Phosphoric Amides

A series of non-cyclic, cyclic and bicyclic phosphotriamidates has been sythesized and their structure, NMR spectroscopic characteristics and their chemical reactivity are discussed.     

利用主成分分析和分层聚类分析法研究氟诺喹酮类药物分子结构活性关系

用密度泛函理论计算了12种具有抗肺炎链球菌的氟诺喹酮类药物分子的分子特性.利用主成分分析和分层聚类分析方法来简化氟诺喹酮类药物数据库的维数.主成分分析法表明,变量 E_(LUMO)、 Q_3、Q_5、Q_A、lgP、MR、VOL、ΔE_(HL)能够有效地对抗肺炎链球菌的氟诺喹酮类药物进行分类.分层聚类方法的结果和主成分分析方法的结果一致.这表明两种方法都能够对新的具有抗肺炎链球菌的氟诺喹酮类药物的分类提供一个可信的规律.利用主成分分析法和分层聚类分析法对其他6个氟诺喹酮类药物分子进行分析,结果都表明有两个药物分子具有较强的抗肺炎链球菌活性.此结果和临床结果相吻合.     

MOLMAP指数及其在变异性预测中的应用

分子映射(MOLMAP)指数是以分子的化学键描述符为基础,通过Kohonen自组织映射依据一定的算法而衍生.化学键描述符是由化学键的物理化学性质,如两端原子的电荷差和拓扑性质,键连杂原子数量等所组成.本文将分子映射指数应用于4075个有机物质(Ames实验结果:2305个结构有诱变性,1770个结构无诱变性)的变异性预测.通过随机森林,分别采用三种类型的指数建立模型:(1)采用不同维数的分子映射指数;(2)采用全局分子描述符;(3)将分子映射指数与全局分子描述符相结合.整个数据集的集外(out-of-bag)交叉验证的正确预测率达到85.4%.为了检验模型的稳定性,采用所建模型预测源于另一数据库的472个化合物,正确预测率为86.7%,与此前的研究相比,两个预测结果均有所提高.     

Process Induced Micro Structure Evolution in Polyester Polyurethane and Mechanical Properties Relationship

Summary: MDI-HQEE-Capa based thermoplastic polyurethane (TPU) with Shore hardness of 94 A was injection molded. In order to study the influence of melt conditions on the material structure evolution and resulting mechanical properties a systematical variation in processing temperatures in the range between 195 °C and 250 °C was applied. The mold temperature was kept constant at 60 °C. Process induced samples morphologies were investigated by means of light microscope (LM), scanning electron microscope (SEM) and differential scanning calorimeter (DSC). Mechanical visco-elastic properties were determined by means of cyclic tensile experiment and were correlated with results of structural investigations. The evaluation of morphology micrographs of raw TPU material and specimens molded at different temperatures shows a reduction in visual crystalline fraction. This gains a distinct change in the deformation behavior of injection molded TPU with increasing melt processing temperature.     

有限集合上偏序关系的矩阵判别方法

要从定义出发去判断集合X上的二元关系R是否是偏序关系比较困难,从关系矩阵出发,给出了偏序关系的矩阵判别方法,并对此方法进行了证明.     

Macroporous Polymers with Hierarchical Pore Structure from Emulsion Templates Stabilised by Both Particles and Surfactants

Inspired by natural porous materials, such as wood, bamboo and spongy bone consisting of individual structural units that are hierarchically arranged to optimise mechanical properties such as strength and toughness, synthetic macroporous polymers with enhanced physical properties were created by emulsion templating. Hierarchical poly(merised) high internal phase emulsions (HIPE) were created from HIPEs stabilised simultaneously by particles and a surfactant. In these HIPEs, surfactant stabilised and particle stabilised water droplets coexist, which upon polymerisation of the minority oil phase gives rise to macroporous polymers with a hierarchical pore structure. An improvement of the mechanical properties of our hierarchically structured macroporous polymers at equal porosity was observed, due to a more efficient packing of pores in a configuration that improves mechanical strength despite the presence of interconnecting pore throats. Moreover, the permeability of the hierarchically structured polyHIPEs are exceeding those measured for conventional polyHIPEs made from surfactant only stabilised HIPEs.

     

Regioselectivity in 2-X-pyrazine aminations by O-mesitylenesulfonylhydroxylamine

The regioselectivity of 2-X-pyrazine aminations by O-mesitylenesulfonylhydroxylamine was studied experimentally and the results are discussed from the viewpoint of electronic and steric factors. DFT calculations are consistent with the reaction proceeding according to an S_N2 mechanism.     

饮用水新型含氮消毒副产物卤乙酰胺稳定性研究

饮用水氯化消毒工艺向氯胺消毒工艺的转变, 降低了三卤甲烷(THM)和卤乙酸(HAA)等消毒副产物(DBP)的浓度, 但增加了毒性更强的含氮消毒副产物(N-DBP)含量, 卤乙酰胺(HAcAm)便是其中的代表. 本研究结合线性自由能关系(LFER)理论, 考察了HAcAm在不同pH条件下的水解特性, 以及不同氯投加量条件下的氯化特性, 并探讨了HAcAm的水解和氯化反应路径. 结果表明, 在较强的酸性条件下(pH＝4)二氯乙酰胺(DCAcAm)将发生水解反应, pH＝5时DCAcAm较为稳定, 三氯乙酰胺(TCAcAm)在酸性条件下未产生明显的水解现象; 碱性环境中TCAcAm和DCAcAm皆发生明显水解反应, 反应符合一级动力学, 保存DCAcAm和TCAcAm水样时需调pH至5左右. 氯化消毒会产生较高浓度的THM和HAA, 但可能会缩减毒性更强的HAcAm等N-DBP在饮用水中的含量. pH＝10时TCAcAm水解后快速生成三氯乙酸(TCAA); 而对于氯化反应, TCAcAm与HOCl反应生成较为稳定的中间产物Cl-N-TCAcAm, 当HOCl浓度较高时, Cl-N-TCAcAm进一步与HOCl反应生成TCAA.