反相高效液相色谱法测定肾复康胶囊中的野黄芩苷和芦丁

建立了肾复康胶囊中野黄芩苷和芦丁的反相高效液相色谱测定方法。以甲醇-水为提取溶剂,采用超声提取法对样品进行前处理。以0.02 mol/L磷酸二氢钾缓冲溶液(含1.0％（体积分数）冰醋酸)-甲醇（体积比为63∶37）为流动相,于330 nm波长下检测,肾复康提取液中野黄芩苷和芦丁可达基线分离,分析时间在20 min内。野黄芩苷和芦丁在10 ~300 mg/L内,其峰面积与浓度之间线性关系良好,目标物的加标回收率大于98％。该方法适用于肾复康胶囊及相关药材中野黄芩苷和芦丁黄酮类化合物的测定和质量控制。     

几种吸附树脂对五氯酚钠吸附性能的研究

研究了几种树脂对五氯酚钠的吸附能力,其中戊二醛交联的壳聚糖树脂不仅有较好的吸附效果,动态吸附容量为187.5mg/g干树脂,而且易洗脱,洗脱率高达90%以上。     

交联壳聚糖树脂对部分尿毒症毒物的吸附性能研究

用反向悬浮的方法制备了戊二醛交联壳聚糖树脂吸附剂,并对制得的球形吸附剂用NaBH4进行了氢化还原处理,以提高其在使用环境下的化学稳定性。扫描电子显微镜(SEM)分析表明,吸附剂的表面形态构成了吸附的微观基础。通过对部分尿毒症毒性物质的吸附研究发现,本文研制的壳聚糖吸附剂对这些目标物均产生了一定的吸附作用,吸附平衡时间符合临床要求,其对3种小分子尿毒症毒性物质的吸附能力依肌酐、尿酸、尿素的次序递增,而对促皮质素(ACTH)的吸附量则达到了13.04mg/g,显示了该类吸附剂应用于临床治疗的潜在价值     

混凝土断裂过程的力学模型与数值模拟

混凝土是一种典型的非均匀准脆性材料,其断裂过程是非常复杂的.评述了混凝土断裂以及断裂过程研究的进展状况,主要总结了一些研究混凝土断裂的宏观力学方法和模型,介绍了从混凝土的细观层次出发模拟其断裂过程的数值模型.最后,简单介绍了作者用细观数值方法模拟混凝土宏观断裂过程的研究成果.      

基于拓扑描述函数的连续体结构拓扑优化方法

提出了一种利用拓扑描述函数(TDF)作为拓扑设计变量求解连续体结构拓扑优化问题 的新方法. 优化问题的目标函数是结构的整体柔顺性，约束条件为对于可利用材料的体积限 制. 这种方法不仅可以消除拓扑优化中经常出现的棋盘格式等数值不稳定现象，而且能够有 效地抑制传统算法处理此类优化问题时所引发的边界扩散效应. 与其它的基于水平集描述函 数的拓扑优化方法相比，所提出的算法不仅无需求解控制水平集函数演化的双曲守恒方 程，而且合理地考虑了目标函数的拓扑导数信息，因而使得算法的计算效率有了显著的提高.     

A large deviation for occupation time of critical branching α-stable process

In this paper we establish a large deviation principle for the occupation times of critical branching α-stable processes for large dimensions d > 2α, by investigating two related nonlinear differential equations. Our result is an extension of Cox and Griffeath’s (in 1985) for branching Brownian motion for d > 4.     

Chemical equilibrium controlled synthesis of polyoxymethylene dimethyl ethers over sulfated titania

The chemical equilibrium and reaction kinetic behavior in the synthesis of polyoxymethylene dimethyl ethers(DMMn) were investigated over sulfated titania in order to reveal the decisive factor controlling the reaction. The results showed that the molar ratio of adjacent DMMn products in equilibrium solution had the same value, which depended absolutely on the reaction temperature. Meanwhile, the reactions had the same DMMn products distributions under varied reaction conditions. The equilibrium constants of the related step-wise reactions for DMMn formation were equal, which were calculated based on the bulk compositions of the reaction solution. And thus, the selectivity to DMMn was mainly controlled by the chemical equilibrium, i.e., thermodynamic control. In brief, the present results provide some guidance for future synthesis of DMMn.     

Birthrates and delay times of Type Ia supernovae

Type Ia supernovae (SNe Ia) play an important role in diverse areas of astrophysics, from the chemical evolution of galaxies to observational cosmology. However, the nature of the progenitors of SNe Ia is still unclear. In this paper, according to a detailed binary population synthesis study, we obtained SN Ia birthrates and delay times from different progenitor models, and compared them with observations. We find that the Galactic SN Ia birthrate from the double-degenerate (DD) model is close to those infe...     

High selectively oxidative bromination of toluene derivatives by the H_2O_2-HBr system

An aqueous solution of hydrogen peroxide and hydrogen bromide illuminated by a 60 W incandescent light bulb serves as a source of bromine radicals.Various substituted toluenes（NO₂,Cl,Br,H,CH₃） were high selectively brominated at the benzyl position for monobromination in CH₂C1₂ at ice water with catalyst free.This simple but effective bromination of toluene derivatives with an aqueous H₂O₂-HBr system is characterized with the use of inexpensive reagents and a lower impact on the environment, which make it a good alternative to the existing bromination methods.