查询词典 selectivity

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。

It is a new technique to synthesize SAPO 34 molecular sieve using cheap triethylamine (Et 3N) as the template, and the selectivity of this molecular sieve for ethene and propene can be improved further.

采用X射线衍射、扫描电镜、氨吸附红外光谱及核磁共振等表征手段，研究了以氟化氢三乙胺为复合模板剂合成的SAPO 34分子筛。

Among them, the catalysts with the support of SAPO zeolite performed well properties, Pt catalysts exhibited better performance than Pd catalysts, the activity and selectivity of noble catalysts were much better than that of non-noble metal catalysts. The carbides and oxides of W and Mo also performed well for n-heptane isomerization.

正庚烷异构化催化剂中，研究较多的是以SAPO、HZSM-5和Y、β型分子筛为载体的贵金属催化剂，其中SAPO分子筛载体的性能较优，Pt比Pd具有更好的催化性能，非贵金属／分子筛催化剂的活性比贵金属／分子筛催化剂相差较大。

ABSTRACT: Silicoaluminophosphate molecular sieves are microporous crystals with the structure of SiO2、AlO2－、PO2+ tetrahedral units.The physical—chemical properties of SAPO are not only similar to silicoalumino zeolites but also similar to some aluminophosphate zeolites.SAPO is a novel class of catalytic materials which exhibit excellent shape—selectivity、thermal and hydrothermal stability.

摘 要：磷酸硅铝分子筛是由SiO2、AlO2－、PO2＋三种四面体单元构成的微孔型晶体，它的物化性质不仅类似于硅铝沸石，同时具有某些铝磷酸盐分子筛的特性，是一种具有优异的择形选择性以及热稳定性和湿热稳定性的新催化材料。

Saprolegnia disease :the most common pathogens are two generas of Saprolegnia and Achlya ,and not strictly selectivity on the host.

水霉病：病原最常见的是水霉和绵霉两属，对寄主没有严格的选择性。

Active tra ort : This proce is characterized by selectivity and saturability and requires energy expenditure by the cell.

主动转运这种转运过程的特征是选择性和饱和性，需要细胞的能量消耗。

Carrier-mediated diffusion is characterized by selectivity and saturability: The carrier transports only substrates with a relatively specific molecular configuration, and the process is limited by the availability of carriers.

载体只转运那些具有特异性分子构型的底物。转动过程受有效载体数量控制。

In recent years, the popularity for the use of capillary electrophoresis in the pharmaceutical field has been accelarated by its simplicity, high efficiency and selectivity, large separatory capacity, and its relatively lower operational cost.

近年来，毛细管电泳因其具有较高的分离柱效、选择性和分离能力以及快速、进样量小、操作简便并易于实现自动化等特点在药物分析方面倍受青睐。

The results show high selectivity when the temperature is controlled at 50 CC , and the nitrated reaction time is 90 mm, toluene is nitrated by using 95% nitric acid as nitrating reagent at the presence of acetic anhydride, 1.0g silicotungstic acid catalyst is calcinated at 300℃ for 1.5h. The o/p (ratio of ortho to paro isomer of toluene nitration) ratio is 0.89 in product distribution of toluene nitration, lower than 1.67 using sulfonitric acid as catalyst. The yield of products is 91.6%.

结果表明，在醋酐存在条件下，以CCl4为溶剂，以质量分数为95%的硝酸为硝化剂，反应温度控制在50℃，反应60 min， 1.0g经300℃焙烧1.5h后的硅钨酸催化剂，对甲苯表现出强的区城选择性，甲苯硝化产物o/p值（甲苯硝化产物邻位和对位异构体的质量比）达0.89，较硝硫混酸的1.67显著降低，产物收率达到91.6%。

The adsorption isotherms for mixture of xylose and sorbinose on 732Ca〓 and 732Fe〓 ion exchange resins are measured. All the linear equilibrium relationships are obtained in the experimental condition. The adsorption selectivity of 732Fe〓 is preferred.

本文用静态法测定了木糖—山梨糖混合溶液在732Ca〓型和732Fe〓型树脂上的吸附平衡关系，结果表明，在实验浓度范围内，吸附等温线为线性，732Fe〓型树脂的吸附选择性优于732Ca〓型树脂。

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。