GaAs1—xPx：N中氮浓度的光吸收法测量

在液氮温度下利用光吸收法测量了一组混晶材料GaAs_(1-x)P_x :(0.60相似文献   

Flow microcalorimetry as a tool for an improved analysis of antibiotic activity: The different stages of chloramphenicol action

Summary Flow microcalorimetry in combination with photometric mass determination of staphylococci in suspension was used to reveal alterations in the intensity, extent and efficiency of bacterial metabolism during inhibition of protein synthesis by chloramphenicol. It could be demonstrated that these three parameters of metabolic activity were distinctly affected by this drug, and that the method described promises to be a more reliable tool for assaying the degree and the mode of bacteriostatic inhibition than the conventional determination of the minimum inhibitory concentration.     

发射光谱定量测定重晶石中的锶

本文介绍用发射光谱测定重晶石中钻的含量.先以增量法测出A·R试剂硫酸钡中的错,然后以此试剂作空矿稀释样品,再以三标准试样法进行测定·本文提供的光谱条件可用作测定其它钡盐中错的含量.     

液膜法提取发酵液中的苯丙氨酸 Ⅱ.操作工艺条件

采用乳化液膜法，对分离和浓缩苯丙氨酸的一些重要操作参数：搅拌速度、环境温度、外相ｐＨ值、油内比、处理比和料液初始浓度等进行了研究，得出了既能保持膜稳定性又能保持较高分离效率的最佳工艺条件。以发酵液为背景，对发酵液中的杂质如氯化钠、葡萄糖，金属阳离子及杂质氨基酸存在下的选择性进行了教察，在此基础上对苯丙氨酸的实际发酵液的萃取也进行了研究，并提出了改进传质效率的方法。     

球壳上台阶孔口应力集中分析

对球壳上台阶孔口的应力集中问题进行了分析。利用弹性力学方法简化模型,推出了集中应力的解析表达式。此表达式经实验及数值计算证明是正确的。因此,本文为球壳上台阶孔口的强度分析提供了理论依据。     

高分子多孔小球GDX系列对水中微量大分子有机物富集作用的研究

本文采用间歇法和紫外分光光度法,测定了国产高分子多孔小球 GDX 系列对阴离子表面活性剂十二烷基苯磺酸钠、非离子表面活性剂聚乙二醇辛基苯基醚(tritonx-100)以及黄腐酸的吸附速度和吸附容量。结果表明 GDX 系列对上述三种大分子化合物均有一定的吸附容量和吸附速度,可作富集剂使用,其中 GDX-203的吸附容量较大,平均吸附速度较快。采用柱吸附法和紫外分光光度法测定了 GDX-203对上述三种物质的富集回收率。结果表明实验条件下使用 GDX-203作为富集剂较合适。     

东亚沙尘暴数值模拟：Ⅱ个例分析

利用文献中设计的沙尘暴预报模式,详细地模拟了一个发生在东亚地区的沙尘暴天气过程,得到了滗尘暴起动,传输和沉降的具体特征。     

利用小波变换消除颗粒物Mie散射对DOAS技术的影响

为消除烟气中颗粒物Mie散射对差分吸收光谱(DOAS)法反演气体浓度的影响,提出了多项式结合小波变换的滤波方法.数值研究结果表明:对不同的颗粒物浓度和不同的气体浓度,采用该滤波方法都能够大幅度降低气体浓度的反演误差,且小波变换的层数随颗粒物浓度的增加而增加.实验研究表明:基于该滤波方法的DOAS技术,对0~1377.2mg/m3范围内的SO2气体,其浓度反演误差大都在10%以内,零点漂移由50.96mg/m3降为9.96mg,/m3,提高了DOAS技术的测量精度.     

Elemental composition in surface snow from the ultra-high elevation area of Mt. Qomolangma （Everest）

A total of 14 surface snow （0-10 cm） samples were collected along the climbing route （6500-8844 m a.s.h） on the northern slope of Mt. Qomolangma in May, 2005. Analysis of elemental concentrations in these samples showed that there are no clear trends for element variations with elevation due to redistribution of surface snow by strong winds during spring. In addition, local crustal aerosol inputs also have an influence on elemental composition of surface snow. Comparison between elemental concentration datasets of 2005 and 1997 indicated that data from 2005 were of higher quality. Elemental concentrations （especially for heavy metals） at Mt. Qomolangma are comparable with polar sites, and far lower than large cities. This indicates that anthropogenic activities and heavy metal pollution have little effect on the Mt. Qomolangma atmospheric environment, which can be representative of the background atmospheric environment.