查询词典 selectivity

The C2 selectivity over p-type semiconductor membranes is higher than that over n-type semiconductor membranes and the order of C2 selectivity is consistent with that over p-type semiconductor membranes.

但p型半导体膜上的C2烃选择性比n型半导体膜上的要高；p型半导体膜上C2烃选择性与其电导率大小顺序相一致。

At the heavy metal concentration of 3-4ppm, our study on adsorption capacity, adsorption selectivity of montmorillonite, illite and kaolinite to Cu〓、 Pb〓、 Zn〓、 Cd〓、 Cr〓 shows that the adsorption capacity is mainly determined by the capacity of exchangeable cations and the adsorption capacity of the three clay minerals decreases in this sequence: montmorillonite ＞＞ illite＞kaolinite. It is found that clay minerals have obvious adsorption selectivity to various heavy metals. Montmorillonite exhibits a stronger affinity to Cr〓 and Cu〓 while kaolinite and illite sorb Cr〓 and Pb〓 more effectively. At the same heavy metal concentration, adsorption amount of clay minerals to heavy metals increase with increasing pH value of the solution.

在痕量浓度下，研究了蒙脱石、伊利石、高岭石三种粘土矿物对Cu〓、Pb〓、Zn〓、Cd〓、Cr〓五种重金属离子的吸附容量、吸附选择性及其介质条件对吸附量的影响，结果表明，粘土矿物的阳离子交换容量越大，对重金属离子的吸附容量也越大，其大小顺序为蒙脱石＞＞伊利石＞高岭石；同时，不同粘土矿物对重金属离子具有明显的吸附选择性，蒙脱石对Cr〓和Cu〓有较好的选择性，伊利石和高岭石则对Cr〓和Pb〓有较好的选择性；随着吸附溶液pH值的增大，其吸附量有增加的趋势。

The third part elaborates the strategy of selectivity attention and the factors which affect it, then combining with the design of web-based course "The Design of Active Sever Page" which was designed by the writer, elaborates how to apply the strategy of selectivity attention in the the web-based course: 1 design clear navigator; 2 ascertain the target of instruction; 3 take problem as the direction to cause the student's attention;4 the preceding analysises: the analysis of the need of study, the analysis of learner and the analysise of study content; 5 combining muultiual sensorial passages to present the stimulability to course the attention of the learner; 6 enhance the characteristic of the main body to cause the student's attention;7 emphasize the student's position as main body.

第三部分详细介绍选择性注意策略及影响选择性注意策略的因素，之后结合笔者设计的《 ASP 动态网页设计》网络课程具体阐述网络课程中选择性注意策略的应用：1设计清晰的导航；2确定可观察可测量的教学目标；3以问题为导向引起学生的注意；4前端分析：学习需求分析、学习者分析和学习内容分析；5多通道结合呈现刺激，引起学习者的注意；6强化主体的特征引起学生的注意；7强调学生的主体地位。

SiO〓 crystal transformation was improved by adding Na〓SO〓, alpha cristobalite but not tridymite was catalytic active support. C〓 selectivity was improved by adding W and P, and suppressed deep oxidation property of SiO〓. W-O in catalyst surface was not active species. The support combined with S, W, P show low activity and high C〓 selectivity.

Na〓SO〓的加入促进了SiO〓晶型的转化，α-方石英是催化活性载体成分，而鳞石英没有甲烷氧化偶联反应活性。W和P的加入改善了C〓烃的选择性，抑制了SiO〓的深度氧化特性；W-O物种不是催化活性物种；由S、W、P及SiO〓组成的载体反应活性较差，但选择性较好；同时S元素对C〓烃的选择性的贡献有限。

The test results indicate that the zincate catalyst systems can accelerate these reactions high-effectively, so its selectivity is up to 100% and TOF is 5472h -1, and the activity and the selectivity of the catalyst are kept in six times, and the catalyst system can be availab.

研究了离子液体助催化的各种无机盐催化剂体系用于二氧化碳和环氧化合物通过环加成反应制备环状碳酸酯，结果表明锌盐催化剂体系能够非常高效地催化该反应，最高得到了 5 472h- 1的催化转化频率和 10 0 %的选择性，催化剂使用六次以后没有发现催化活性和选择性的下降，并且该催化剂体系能够适用于各种结构的环氧化合物。

In the same time, water-soluble bidental phosphines ligand BISBIS sulfonated 2,2''-bis(diphenylphosphinomethyl-1,1''-biphenyl was synthesized, and water-soluble rhodium complex Cl was synthesized in situ. This complex which was used as catalysts to catalyze the hydrogenation of avermectin was also tested. Although the rhodium complex containing bidentate phosphine BISBIS showed a higher catalytic activity than one containing TPPDS, the selectivity for ivermectin was lower. How to improve the selectivity will be needed to studied in futur.

同时我们用磺化的2，2''-二-- 1，1''--联苯，以及它们的水溶性威尔金森型铑配合物和环辛二烯的阳离子铑配合物，在利用这些配合物作催化剂，考察它们在各种反应条件下对阿维菌素的选择加氢，由于反应条件以及复合催化剂体系的组成还需要进一步优化，虽然双齿膦配合物显示了较高的活性，然而选择性还有待进一步提高。

Its very difficult to support metal on the surface of crude CNTs. Compared with Pt/C,Pt/CNTs have higher performances in term of efficiency and selectivity. It can be concluded that the interaction between metal and CNTs favors both the high activity and selectivity in cinnamaldehyde hydrogenation.

Pt/CNTs在选择性肉桂醛的选择性加氢中表现出很高的加氢活性和选择性，这是由于纳米碳管外表面独特的结构以及纳米碳管和金属之间相互作用的结果。

For research of bivalve's effect on marine plankton community structure, we conducted Aug.—Dec. 1996 experiment to study the two bivalves' feeding selectivity and their filter－feeding rates. For observing the feeding selectivity, Chlorella sp., Chaetoceros muelleri, Lermmerman, Nitzschia closterium and Pyramidomonas sp.

于1996年8—12月，分别从青岛海洋大学太平角实验基地和胶南市水产养殖研究所采集海湾扇贝和太平洋牡蛎，采用室内实验的方法，比较研究了不同规格的两种贝类对4种不同大小藻类的选择性及水温对其滤除率的影响。

To improve the selectivity, the Co/Mn/Br catalyst system with ethanal as an additive was studied and the reaction conditions were also optimized, which were as follows:the amount of ethanal 10%(mole ration base on the substrate), reaction temperature 100℃,reaction time 30min,the oxygen pressure 0.2MPa, the amount of the composite catalyst Co/Mn/Br 7%,the mass ration of different ingredients 2:2:1. Under these conditions, the yield comes to 24.10% and the selectivity reaches 75.03%.

为了提高反应的选择性，论文初步研究了以乙醛作为添加剂条件下各工艺参数的影响，并进行正交优化，得出最佳条件为：乙醛加入量1：10，反应温度100℃，反应时间30min，氧气压力0.2MPa， Co/Mn/Br混合催化剂加入量7%，质量比2：2：1，在此条件下，反应产率为24.10%，选择性可达75.03%。

The results show that among the acetoacetonate complexes,Co_3 has the best catalytic activity.The optimum reaction conditions were as follows:0.764 mmol of Co_3,mole fraction of ethanal 10%based on the substrate,room temperature,oxygen pressure 2 MPa,reaction time 11h and solvent acetonitrile.Under these conditions,13.3%p-chlorobenzaldehyde was obtained with 15.3%conversion and 87.2%selectivity.The oxidation can also be carried out without solvent with 8.1%conversion,89.1%selectivity and 7.2%yield respectively.

在金属配合物中Co_3的催化性能最好，在其用量为0.764 mmol、乙醛用量为反应物物质的量的10%、氧气压力为2MPa时，以乙腈为反应介质，室温下反应11h，反应的转化率和选择性可达15.3%，87.2%，对氯苯甲醛收率可达13.3%；反应也可在无溶剂时进行，此时反应的转化率、选择性及醛的收率分别为：8.1%，89.1%，7.2%。

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。