选择性

A potentiometric method for the determination of the apparent mean activity of NaCl in saline soils in situ was proposed.

使用锥形氯离子选择性电极和钠离子选择性电极，研究了在田间直接测定原位土壤中的氯化钠平均活度问题。

The effect of silicon atom in substrate on the reaction rate and the stereoselectivity of enzymatic reactions was revealed by comparison of horse liver alcohol dehydrogenase-catalyzed stereoselective dehydrogenation of the three isomers of acetyltrimethyl propanone and their carbon analogues in aqueous/organic biphasic systems.

本项目通过对比在水－有机溶剂两相系统中，马肝醇脱氢酶催化三甲基硅烷丙酮的三个异构体及其碳类似物的光学选择性脱氢反应，揭示了底物中的硅原子对酶反应速度、立体选择性的影响规律，成功地合成了高对映体纯度的手性有机硅醇，并实现了辅酶的再生。

This paper reports the experimental equipment and technology parameter for the synthesis of diisopropylbenzene and triisopropylbenzene by catalytic alkylation between benzene and propene, the conversion of benzene is more than 98%,the selectivity of diisopropylbenzene and triisopropylbenzene is more than 40% and 36% respectively.

报道了苯与丙烯催化烷基化合成二异丙苯和三异丙苯的实验装置与工艺条件，苯的转化率达98%以上，二异丙苯的选择性≥40%，三异丙苯的选择性≥36%，经分离后可获得纯度≥95%的二异丙苯和三异丙苯产品，所提供的合成工艺基本上无污染，在国内外具有先进的技术。

The influences of conditions, such as the different elements in A site, reaction temperature and the reoxidation time etc.on partial catalytic oxidation of AFeO 3 catalyst are reviewed. The results show that the lattice oxygen from AFeO 3 pervoskite catalyst in A site occupied ...

结果表明，稀土金属(La ，Nd ，Sm ，Eu)占据A位的AFeO3钙钛矿型催化剂中的晶格氧适于甲烷选择性氧化制合成气，在完全氧化的LaFeO3催化剂上存在少量的强氧化性氧物种，通过控制再氧化条件，可使CH4 在LaFeO3催化剂的作用下，高转化率(～ 92 %)、高选择性(96 %)地生成合成气。

The catalytic performance of the synthesized molecular sieves, modified by Pd or Pt, for isomerization and dehydroisomerization of n butane was investigated. Pd/SAPO 11 catalyst showed the highest selectivity in...

结果表明，载 0 3%Pd的SAPO 11分子筛催化剂具有最高的丁烷异构化选择性，而在丁烷一步异构脱氢反应中，含金属杂原子的催化剂具有更高的异丁烯选择性。

Results Compared with percutaneous coronary angiography,the sensitivity of sixteen slice sparil CT in diagnosing moderate and severe coronary stenosis was 83.33%,and the specificness,positive predictive value,negative predictive value and degree of accuracy was 91.40%,85.59%,89.95% and 83.33% respectively.

对16层螺旋CT显示冠状动脉狭窄和经皮选择性冠状动脉造影显示冠状动脉狭窄进行定量评价。以经皮选择性冠状动脉造影结果作为诊断的金标准。计算出16层螺旋CT冠状动脉成像对冠状动脉狭窄的诊断准确性指标。

The stereochemical studies of PPCs derived from the copolymerization of CO_2 with chiral PO at various conditions reveal that the polymer enantioselectivity is proportional to its head-to-tail linkages with regard to regioselective ring-opening of the epoxide.

通过研究聚碳酸酯的立体化学发现聚合物的对映体选择性与环氧丙烷区域选择性开环存在一定的影响作用。

In the area of selective catalysis, they will soon publish the first examples of stereochemically thoroughly investigated Enantioselective Organo-Autocatalysis, a process that demonstrates conceptually new catalysis design strategy and also provides structurally well-defined small-molecule models that may help explain the origin and maintenance of homochirality fundamental to the functions of biological systems.

在相邻的选择性催化领域，他们即将发表设计发现的首例有机小分子催化的高立体选择性自复制过程（Enantioselective Organo-Autocatalysis），此类反应不仅避免了繁琐的催化剂和产物分离问题，更有意义的是充分利用了产物自身的催化功能，并为分子手性单一性这一生命体根本特征的起源和自发维持提供了第一个简洁的小分子模型系统。

The type and concentration of thiophenic sulfur in gasoline and diesel fuel were determined separately by gas chromatography with a sulfur chemiluminescence detector.With activated carbon and 30％aqueous solution of H2O2 as catalyst and oxidant respectively, the experimental studies of oxidative desulfurization of gasoline and diesel were carried out.

采用气相色谱-硫化学发光检测器分析了汽油和柴油中噻吩类硫化物的分布及浓度；以活性炭作为催化剂，以30％过氧化氢溶液为氧化剂，在甲酸存在条件下考察了汽油和柴油中噻吩类硫化物催化氧化脱除的选择性，讨论了硫化物中硫原子电子密度对硫化物氧化选择性的影响。

Triphenylmethyl chloride can react selectively with the 30-hydroxil group of glycyrrhetol under the catalyzing effects of three ethyl amine and dimethyl amino-pyridine.This condition of the reaction has an important value for the selective protection of 30-hydroxil group of glycyrrhetol.

三苯氯甲烷在三乙胺和二甲氨基吡啶等碱性催化下与甘草萜醇的C30-位羟基进行选择性缩合反应，此反应产率较与C3-位羟基化反应的要高，此种反应条件在甘草萜醇C30-位羟基的选择性保护中具有重要的价值。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。