Seeded Crystallization of Leucite

The leucite crystallization kinetics from a hydrothermally derived precursor seeded with nano-crystalline leucite was investigated by X-ray diffraction and non-isothermal differential thermal analysis. The nano-crystalline leucite was prepared by high-energy milling of high-purity leucite powder and the leucite precursor was prepared by the hydrothermal method of silica sol, aluminum nitrate, and potassium nitrate. After the seeds were introduced, the crystallization temperature of the precursor was lowered by 100°C and the transition phase kalsilite did not appear during the crystallization process. When the seeded precursor was heat treated at 700°C, a small amount of cubic leucite was stabilized to room temperature. The seeded precursor showed an exothermic peak between 800° and 920°C under different heating rates. The activation energy for the growth of leucite from the seeded precursor was 256(SD9) kJ/mol.     

黄荆提取物对几种害虫的杀虫活性

研究了黄荆种子二氯甲烷提取物对5种害虫的杀虫活性以及对天敌异色瓢虫的安全性。结果表明：黄荆提取物对菜青虫、小菜蛾、麦长管蚜和桃蚜都有较高的杀虫活性，尤其是对菜青虫的活性最高，稀释100倍，处理4龄幼虫死亡率可达93．3％。但对大猿叶甲的杀虫活性则很低。黄荆提取物对异色瓢虫幼虫有一定的杀虫活性，但对其成虫无任何影响。本研究结果为开发利用这一新的杀虫植物资源提供了依据。     

浅论食品添加剂的安全性

介绍了食品添加剂的定义、分类和作用 ,分析了国内外食品添加剂的现状、发展前景及存在的问题 ,综述了食品添加剂的安全性问题及监督管理办法。     

Phase separation in polymer blends comprising copolymers: 6. Effect of molecular architecture of block copolymers

To study the effect of the molecular architecture of a copolymer on its miscibility with corresponding homopolymers a series of block copolymers of styrene and isoprene with diblock, triblock and four-arm star architectures have been prepared and the morphologies of the blends of the copolymers and polyisoprene with different molecular weights have been examined by electron microscopy. The results show that miscibility varies in the sequence diblock>triblock>four-arm star copolymers. This sequence is in the opposite direction to the variation of the architectural complexity of the block copolymers, i.e. the more complex is molecular architecture, the greater is conformation restriction in microdomain formation and the less is solubility of homopolymer in corresponding domains.     

英汉情感隐喻的共性与差异

为进一步了解情感隐喻的实质,以人类基本情感的隐喻表达作讨论对象,对英汉语言中的基本情感隐喻进行共性与差异分析。     

民办高校外籍教师的绩效管理研究

探讨民办高校外籍教师绩效管理应遵循制度化、科学化、精细化、人文化等原则:民办高校外籍教师绩效管理的内容应包括制度管理、教学管理、生活管理及绩效考核等方面.     

圆管层流脉动流动的数值模拟

为研究圆管层流脉动流动特性,建立了二维非稳态轴对称模型,对壁温恒定、入口速度周期性变化的流体进行数值模拟.分析了速度振幅和频率对层流流动的影响,得到了频率和振幅对压力、温度、壁面摩擦系数影响的规律.研究表明:脉动流动时,压力、温度、壁面摩擦系数围绕相同Re下稳态流动时的数值波动;压力与速度之间存在相位差;压力、壁面摩擦系数的波动与速度振幅和频率成正比;温度的波动与速度振幅成正比,与频率呈反比;当流体脉动的频率和振幅足够大时,会在近壁面处出现回流,并且出现回流的时间会随着频率和振幅的增大而增长.     

悬挂式重力补偿系统精密跟踪方法

介绍了一种用于研究空间机器人微重力条件下的工作特性的悬挂系统——悬挂式重力补偿系统,并给出了悬挂模块的动力学模型.通过数值求解与仿真,运用非线性规化求出了一定条件下的最优控制参数;用正交试验寻优、基于时间最优控制的试凑法证明了优化模型的解正确性.该研究为空间机器人地面试验系统模拟微重力环境下精密跟踪运动提供了最优控制方法.     

基础项目融资中政府担保的定价

在基础项目融资中,政府提供的担保有效地促进了基础项目融资的发展.政府提供担保会给政府造成或有债务,需要采用定量方法研究担保,从而为政府的担保提供量化依据.论文在分析担保期权特性基础上,采用期权理论建立了担保的定价模型,并研究了模型在基础项目融资收益担保中的应用.