查询词典 selectivity

Octylene was synthesized via tetramerization of ethylene at the presence of a catalyst system consisted of chromium acaet as primary catalyst, methylaluminoxane as cocatalyst, bis amine as ligand under high pressure. The effects of different PNP ligands on catalyst activity and selectivity to 1-octene were investigated.

在乙酰丙酮铬、甲基铝氧烷、配体三元催化体系中，以乙烯为原料在高压下齐聚生成1-辛烯，主要考察N原子上取代基不同的PNP配体对催化剂活性及1-辛烯选择性的影响。

Olid superacids as SO42VZrO2 can overcome these disadvandages, and perform higher activity and better selectivity in esterification.

O_4~(2-)／ZrO_2型固体超强酸克服了这些缺点并对酯化反应表现出较高的反应活性和较好的产物选择性。

From its introduction, oncological chemotherapy has been encumbered by its poor selectivity because most antiproliferative drugs are toxic not only to tumor cells but also to important populations of the body's non-neoplastic cells.

由于它的介绍， oncological化学疗法由它的劣质的选择性妨害了，大多数antiproliferative 药不仅对瘤细胞而且对身体非新生物的细胞的重要的人口是有毒的。

The recent advancement of the asymmetric addition of organozinc reagent s to ketones and α-ketoesters is reviewed according to the type of the chiral ligands, with an emphasis on the introduction of the ligands with high efficiency and high selectivity.

按照手性配体的结构类型分类，综述了近年来有机锌试剂对酮、α-酮酯等化合物的不对称加成反应的研究进展，对高效、高选择性的手性配体在该类反应中的应用进行了重点评述。

The results showed that not only the conversion of TMPD and the selectivity to green oxane were almost the same,but also the catalyst was easily separated and recycled as compared with conventional catalysts.

结果表明：与传统催化体系相比，该体系不仅具有相当的转化率和选择性，而且具有催化剂分离简单、可循环使用的优点。

A polymer that had the highest binding selectivity and capability was used as solid-phase extraction sorbents for direct extraction of TBZ from different biological and environmental samples (cabbage, pannage, shrimp, orange juice and tap water).

三、以合成最优的戊唑醇分子印迹微粒作为固相萃取剂，检测包菜、饲料、虾肉、桔汁、水中痕量的戊唑醇。

The samples were characterized by XRD and SEM, and the permeant selectivity of the membrane was characterized by single-gas at room temperature.

用X射线衍射和扫描电镜表征分析了沸石膜的形态，并通过单组分气体渗透实验对合成膜管的渗透性能进行了测试。

In order to decrease toxicities of retinods and enhance pharmacal effects and gain the relative derivatives with better curing effect and selectivity, structures of retinoic acids were modified by inducing glycosyl groups in this paper.

方法一是在氢氧化钾存在下，以4-二甲氨基吡啶做相转移催化剂，将溴代-O-乙酰基葡萄糖(5a)、溴代-O-乙酰基木糖(5b)、溴代-O-乙酰基乳糖(5c)和溴代-O-乙酰基麦芽糖(5d)分别与异维A酸反应制得1-O-异维A酰-乙酰基单糖(6a，6b)和1-O-异维A酰-乙酰基二糖(6c，6d)，收率为53～65%。

Thus, the focus of our study is to design near-infrared fluorescent probe with good selectivity, high sensitivity, good photostability and working within the acidic pH range.

另外，用于检测酸性器官内的尤其是理想的pH探针几乎没有，这被认为是细胞生物学及医学发展的瓶颈。

Both Pseudomonas and Pantoeu universally exist on Bursaphelenchus xylophilus in diseased pines, and there is selectivity for pine wood nematodes to carry bacteria. Bioassay results show that both strains of Pseudomonas and Pantoea are phytotoxin producers.

由此可知，假单胞菌和泛菌分布较广，在所有采样疫区感染松材线虫病的马尾松和黑松病死木中都能分离到，是普遍存在病木组织中松材线虫携带的主要细菌。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。