结构单元

3A series of C_2-symmetric chiralβ-amino alcoholsⅢ-6 andⅢ-10were synthesized in several steps from natural amino acids,and applied in the asymmetric borane reduction of prochiral ketones.The catalytic activity ofⅢ-6 was better thanⅢ-10.

3以天然氨基酸为起始原料，经过简单的几步反应合成了开链冠醚类C_2-对称的手性β-氨基醇Ⅲ-6以及Ⅲ-10，将其应用于硼烷对前手性酮的不对称还原反应中，含有脯氨醇结构单元Ⅲ-6的催化效果要好于由其他氨基酸衍生的Ⅲ-10，THF为溶剂，回流，催化量为10 mol%时，最高得到85%的ee值。

This Sm-catalyzed reaction firstly efficiently realized the catalytic cycle in the tandem rearrangement/reduction reaction of α-hydroxy epoxides, and moreover the diastereoselective amplification could be distinctly observed when two C1 epimers in substrate were subjected to this catalytic tandem reaction.

该催化的多功能串联反应，高度非对映选择性地一步控制了含有季碳的三个相邻立体中心，有效地构建了&2-季碳1，3-二醇&结构单元，首次实现了此类重排—还原过程的催化循环，其中对于两个C1位的差向异构体底物，此反应具有明显的非对映选择性放大特点。

Catalytic enantioselective reduction of imines and enamines represents one of the most straightforward and efficient methods for the preparation of chiral amines, which are not only important building blocks of many natrural products and chiral drugs, but also can serve as useful resolution reagents, chiral ligands and chiral catalysts.

中文摘要手性胺不仅是许多天然产物和手性药物的重要结构单元，而且也是非常有用的拆分试剂、手性配体和手性催化剂。

Many more complex organic compounds have ketones as Building Blocks.

许多更复杂的有机化合物都有酮作为结构单元。

The 3-D anionic framework of JGP-9 is built up from a repetition of an enneameric structural fragment 〓 and HPO〓 tetrahedra.

JGP-11由来自不同二级结构单元分别组成的层堆积而成的含有4-，8-元环孔道的三维开放骨架。

In GeS2-Ga2S3 glasses, the basic structural units forming the backbone ofthe network are GeS4/2 and GaS4/2 tetrahedra which are connected through a bridging sulfur to form a three-dimensional network.

在GeS_2-Ga_2S_3玻璃中，形成网络骨架的基本结构单元是GeS_(4／2)和GaS_(4／2)四面体，它们通过桥硫连接成三维空间网络。

Applied quantum chemistry calculating method and a series of calculating program, ground state energies of Cu-O four bonds which was periodical structure unit of CuO〓 plane, were calculated.

应用量子化学ABINTIO计算法，采用系列程序，分别计算了Cu-O单键、线形Cu-O双键，以及Bi系超导体CuO〓面的周期性结构单元Cu-O四键，在不同的几何构型下的基态能量，并计算了相应于CuO〓面的Cu-O四键在平衡几何构型下的一系列激发态能量。

The grid size, structural height and thickness are designed based on the existent research conclusion and the peculiarities of the self-balanced structure.

目的 为实际工程应用设计具有空间刚度的自平衡预应力结构单元。

This article expounds the principle and operation method to determine the content of structural unit of VA in EVA Resin through the method of soap reaction.

叙述了用皂化法测定EVA树脂中VA结构单元含量的原理和操作方法，特别是对影响测定准确度的主要因素———加水量、加热方式和反应时间进行了探讨，取得了令人满意的结果。

Light condition, direct sunlight, thickness of soil humus, neighboring trees, upper canopy species , herbs and shrubs, on the growth of the young trees of Pinus koraiensis were investigated taking 4 closest neighboring trees as the structural unit of the individual growth environment.

本研究以红松幼树及其周围最近4株相邻木组成的小环境结构单元为研究对象，研究了光照条件、土壤腐殖质层厚度、相邻木、直射光、上层树种、草本和灌木等6个环境因子对红松幼树生长的影响。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。