查询词典 valent

Zero-valent metal can effectively promote the reductive dechlorination of PCBs under high temperature or the existence of Pd, Pt, Ni and Cu as catalyzers.

在高温等特殊条件下或有钯、铂、镍和铜等催化剂存在的条件下，零价金属能有效促进PCBs还原脱氯。

The preparation of epoxides by reaction between alkyl peroxides and olefins catalyzed by high-valent transition metal complexes is one of the most important means of preparation of epoxides.

以高价过渡金属配合物为催化剂，催化烯烃直接环氧化反应是合成环氧化合物的重要途径之一。

Very good results were obtained in logP modeling for carboxylic acid, ethanol, phenol, aldehyde, ketone, ether, ester and amine. A QSPR model of logP for many kinds of substances was established by multi-linear regression with the first-order molecular connectivity valent index 〓 and the number of hydrogen bonds N as two patameters.

利用这两类结构参数，分别建立了脂肪族羧酸、芳香族羧酸、醇、酚、醛、酮、醚、酯、胺类物质的疏水性常数定量模型；在此基础上，建立了包含8类基本有机物144种物质的疏水性常数的定量模型，并提出logP的简化模型。

Topics covered include phosphines, applications of phosphorus and compounds as reagents in synthesis, the chemistry of phosphorus ylides, applications of the Wittig reaction in the synthesis of heterocyclic and carbocyclic compounds, preparation of Iminophosphoranes and their synthetic applications in the aza-Wittig reaction, phospho-transfer processes leading to bond formation, low valent phosphorus compounds and phosphorus methods in oligonucleotide chemistry.

包括的题目包括phosphines，磷的应用和作为在综合过程中的试剂的化合物，磷ylides的化学，在heterocyclic 和carbocyclic 化合物的综合过程中的威蒂格反应的应用， Iminophosphoranes的准备和在aza-威蒂格反应里的他们的合成申请，phospho 转换过程导致在oligonucleotide 化学方面的契约形成，低的化合价磷化合物和磷方法。

Topics covered include phosphines, applications of phosphorus and compounds as reagents in synthesis, the chemistry of phosphorus ylides, applications of the Wittig reaction in the synthesis of heterocyclic and carbocyclic compounds, preparation of Iminophosphoranes and their synthetic applications in the aza-Wittig reaction, phospho-transfer processes leading to bond formation, low valent phosphorus compounds and phosphorus methods in oligonucleotide chemistry.

包括的题目包括phosphines，磷的应用 Application 和作为在综合过程中的试剂的化合物，磷ylides的化学，在heterocyclic 和carbocyclic 化合物的综合过程中的威蒂格回应的应用 Application ， Iminophosphoranes的准备和在aza-威蒂格回应里的他们的合成申请，phospho 转换过程导致在oligonucleotide 化学方面的契约形成，低的化合价磷化合物和磷方法。

Efficacy of 23-valent pneumococcal vaccine in preventing pneumonia and improving survival in nursing home residents: double blind, randomised and placebo controlled trial

在护理之家的常住户中23价肺炎疫苗在防止肺炎和改善存活率中的作用：双盲，随机和安慰剂对照试验

A triple co-valent bond is the sharing of three pairs of electrons.

碳氢化合物属于有机化合物中最简单的一类，又称为烃。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。