酯

A high-performance liquid chromatographic method for the simultaneous separation and determination of aryltetralin lignans and flavonoids in Podophyllum emodi Wall.var. chinesis Sprague was developed. The separation was performed on a Kromasil-C 18 column by gradient elution with phosphate buffer-methanol (0-13min, 50∶50, 33min, 30∶70) as mobile phase at a flow-rate of 0.8 ml/min, with detection 270nm.

首次建立了桃儿七中苦鬼臼葡萄糖甙、4-去甲基鬼臼脂素、表鬼臼脂素、苦鬼臼脂素、苦鬼臼酯酮、鬼臼脂素、鬼臼酯酮、去氧鬼臼脂素、去氢鬼臼脂素等9种木脂素以及山柰酚、槲皮素等2种黄酮类组分同时分离测定的高效液相方法。

The preparation process of self-holing polyimide with organosilicon block includes the following steps: 1 the first reaction of polyacid anhydride in functionality not lower than 2, silicon oil with 2 or more amino or imino groups and polyamine with 2 or more amino groups, and the second reaction with one or several kinds of added isocyanate with 2 or more isocyanate radicals to produce sol of polyamido acid containing organosilicon block; 2 solidifying the sol to obtain solid polyamido acid containing organosilicon block; and 3 imidonating the solid to obtain self-holing polyimide with organosilicon block.

本发明公开了一种有机硅嵌段自发孔聚酰亚胺的制备方法，该方法包括以下步骤：(1)有机溶剂中具有大于或者等于2的酸酐官能团度的多酸酐与具有大于或者等于2的胺基或亚胺基的硅油以及具有大于或者等于2的胺基的多胺反应，随后添加一种或多种具有含有等于或者大于2个异氰酸酯基的异氰酸酯反应，生成含有机硅嵌段聚酰胺酸的溶胶。(2)溶胶固化制成有机硅嵌段聚酰胺酸固体。(3)固体亚胺化，即得有机硅嵌段自发孔聚酰亚胺。

The surface hydroxyl group onto magnetic polyvinyl acetate nanoparticles can be obtained by saponification reaction on their surface.

结果表明，磁性聚苯乙烯颗粒与丁二酸酐发生Freidel-Crafts酰基化反应，可以在颗粒表面引入少量羧基；磁性聚甲基丙烯酸甲酯颗粒分别与乙二醇、二缩三乙二醇、聚乙二醇等发生醇-酯交换反应，可以在颗粒表面接枝不同分子链长度的末端羟基；磁性聚醋酸乙烯酯颗粒经过醇解或皂化反应可以获得表面羟基；磁性聚丙烯酸甲酯颗粒通过乙二胺或1，6己二胺的胺解反应可以得到表面氨基，继而与一氯乙酸反应可以引入亚胺二乙酸基团。

The influence of the behavior, mechanism, product structure and relation of structure with properties for co-curing reaction of epoxy resin and cyanate ester system catalyzed by transition metal acetylaceton, etc. was studied.

研究了用乙酰丙酮过渡金属络合物等促进剂催化促进环氧树脂与氰酸酯(在氰酸酯欠量，适量和过量条件下)的共固化反应行为、固化反应的机理、固化物的结构特征以及结构与性能关系。

Nd_2O_3 was used as catalyst for estrification of Acetic acid with propanol and discussed thevariant conditions in reaction of esterification.

以三氧化二钕为固体催化剂，实现了乙酸和丙醇的酯化反应，讨论了催化酯化的各种影响因素。

Under optimized conditions, yield of n-butyl propionate can he over 80.0%.

在较佳条件下，丙酸丁酯酯化率可达80.0%以上。

Normal propyl cinnamylate was synthesized by the esterification of normal propyl alcohol with cinnamic acid in the presence of potassium bisulfate monohydrate.

应用硫酸氢钾催化肉桂酸与正丙醇的酯化反应合成肉桂酸正丙酯。

Propyl gallate ; synthesis ; esterification ; new technology ; food antioxidant

没食子酸丙酯；合成；酯化；新工艺；食品抗氧化剂

The conversion of acetic acid and the selectivity of propylene reached 85.43% and 98.52%, respectively.

本文还对乙酸与丙烯直接酯化合成乙酸异丙酯的动力学进行了研究。

Kdr resistance and determination of frequences of kdr gene in house fly field population L1014F is the most common amino acid substitution in the kdr allele. The frequency of the L1014F kdr allele was determined by the method of PASA in fourteen field populations of houseflies with resistance factors at LD〓 for pyrethrin/ piperonyl butoxide and bioresmethrin/piperonyl butoxide from 4 to 29 and 2 to 98, respectively.

击倒抗性及kdr基因频率在家蝇野生种群中的检测 L1014F是击倒抗性等位基因最常见的突变位点。14个家蝇种群对除虫菊酯／胡椒基丁醚和苄呋菊酯／胡椒基丁醚的LD〓抗性倍数分别为4到29和2至98。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。