查询词典 selectivity

The results showed that the optimal conditions were as follows: H3PW12O40/Al2O3 exhibited high activity and selectivity at the optimal temperature 330℃ and the load content of heteropoly acid 40%, the glycerol conversion reached 100% with acrolein selectivity of 83.7%.

结果表明，由甘油制备丙烯醛的较优条件为：当催化剂为H3PW12O40/Al2O3，负载量为40%，反应温度为330℃时，丙烯醛的选择性可达83.7％，甘油的转化率为100％。

Combining the performance evaluation (activity, selectivity and stability) and the characterization of the catalysts (XRD, TPD, FTIR and the pore structure measure), it can be concluded that :(1)The activity of modified β is higher than MCM-22, but the selectivity of ethylbenzene is lower about 3% than that of MCM-22;(2)The mounts of diethylbenzene and the other by-products are higher 1.7 times and 1.5 times than these of MCM-22 respectively;(3)The catalytic performance of zeolite mixture is nearly equal to modified β, but the selectivity of ethylbenzene is higher about 0.5% than that of modified β;(4)The catalytic activity of zeolite is mainly correlated with the number of acid sites, strength and distribution, and the distribution of products is determined by the binding energy of ethylbenzene and the pore structure, while the stability of catalyst is affected by the amount of poly-ring aromatic alkylate and the pore structure.

以性能评价和特性表征（XRD、TPD、FTIR和孔结构测定）相结合的方式，对上述三种催化剂性能比较的结果表明：（1）改性的活性明显高于MCM-22，但乙苯选择性却低于MCM-22绝对差约3%；（2）改性(上二乙苯和其他副产物的生成量分别约为MCM-22上对应值的1.7和1.5倍左右；（3）混合型催化剂的性能与改性相仿，但乙苯选择性提高0.5%左右；（4）对乙苯合成，沸石催化剂的活性主要取决于其B酸中心数、酸强度及酸分布，产物分布则取决于催化剂表面的乙苯脱附能垒值和孔道结构，而稠环芳烃的生成量和催化剂孔道结构是影响催化剂稳定性的主要因素。

In 20℃ and 40℃, the selectivity of Cd~(2+) to analcime is less than that of Na~+ to analcime; in 60~(2+) and 80℃,the selectivity of Cd~(2+) to analcime is more than that of Na~+ to analcime.

在20℃和40℃时，方沸石对Cd~(2+)的选择性小于对Na~+的选择性，在60℃和80℃时，方沸石对Cd~(2+)的选择性大于对Na~+的选择性。

First, an image filter, which is "Spatially Multidirectional Selectivity with Neighborhood Characteristics Filter" is presented.

第一，提出了一种结合多方向小波变换屏蔽滤波及邻域特性的图像滤波方法（Spatially Multidirectional Selectivity with Neighborhood Characteristics）。

The conclusions were as follows: theνO-H andνC=O IR absorption maxima shifted towards higher wave numbers after imprinting 17β-estradiol on TFMAA-co-TRIM copolymer with the red shift of theνO-H groups being apparent after precipitation polymerization for 16h while that forνC=O groups being observed after polymerization for 24h. A strong interaction between TFMAA and 17β-estradiol was confirmed by the high selectivity for 17β-estradiol, as indicted by the values of the separation factor of isomers of 17β-estradiol/17α-estradiol (2.28) and the imprinted factor (3.01). Particle diameter of TFMAA-co-TRIM polymer was between 300 nm and 1.5μm, which suited well for solid phase sorbent throughout at low column pressure. The recognition of imprinting TFMAA-co-TRIM polymer for sterol molecules was driven by enthalpy eluted with acetronitile, and low temperature was in favor of the separation of sterol structure analogues on imprinting column. TFMAA-co-TRIM polymer possessed of determinate anti-heat stability, with melting point beginning at 255.84℃, Tp=257.40℃, control TFMAA-co-TRIM polymer and imprinting TFMAA-co-TRIM polymer were respectively decompounded at 267.79℃and 343.11℃, and solid micro-extraction noddle prepared by the special polymerization also showed definite recognition for 17β-estradiol by GC/MS detecting at 270℃. By selection of various washing and elution solvents, elution reagents of close polymerization system were of more advantage in template molecules retention and recognition on molecularly imprinted solid phase extraction column. At a certain extent, progesterone, 17α-estradiol, 17β-estradiol and 4-androstene-3, 17-dione could be intercepted on the MISPE column. Especially, MISPE had high selectivity for progesterone, and imprinting TFMAA-co-TRIM polymer could achieve adsorption balance within 50 min by absorption kinetics test for 17β-estradiol. However, MISPE column showed better selectivity and enrichment property for 17β-estradiol than C18 and CSPE columns according to the data from HPLC and GC/MS analyses. Recovery of 17β-estradiol on MISPE column was up to 85.5% while when prime extracting solution of milk powder was sampled, the recovery of CSPE and C18 columns were 43.7% and 30.7%, respectively.

通过研究阐明：紫外聚合产物TFMAA-co-TRIM中的νO-H振动吸收峰在聚合16h后红移，νC=O振动吸收峰在聚合24h后红移；TFMAA-co-TRIM对雌二醇异构体的印迹因子达到了3.01，α为2.28，优于其它功能单体参与得到的聚合物识别特性；TFMAA-co-TRIM聚合物粒径介于300 nm至1.5μm之间，作为色谱固定相具有良好的通量和低的柱压；在乙腈流动相中，TFMAA-co-TRIM分子印迹固定相的分离过程主要被焓驱动，低温有利于分子印迹固定相分离甾醇结构类似物；TFMAA-co-TRIM分子印迹聚合物在255.84℃时开始熔融，Tp=257.40℃，聚合物CP的降解温度在267.79℃，MIP降解温度在343.11℃，制备的固相微萃取头初步经GC/MS 270℃的耐热性测定；不同的洗提溶剂筛选证明了选择接近聚合溶剂的洗脱体系更有利于MISPE发挥识别效应；分子印迹固相萃取柱对孕酮、17α-雌二醇、17β-雌二醇和雄烯二酮都具有不同程度的保留特性，可作为此类化合物的吸附材料，特别对孕酮强保留的富集特性，可作为孕酮的选择性识别吸附剂，其分子印迹聚合物对17β-雌二醇的吸附动力学测定显示在50 min内基本达到吸附平衡，具有作为传感器核心敏感材料的潜力；对比萃取奶粉中17β-雌二醇性能，MISPE柱比非分子印迹固相萃取柱和C18柱具有更高的保留，回收率依次为85.5%，43.7%和30.7%。

D. of the catalyst increased, i. e. the acid volume of the catalyst increased, the conversion for isobutene and the selectivity for trimer increased also, while the selectivity for dimer decreased, and the selectivity for tetramer was almost unchanged.

D。增加时，即催化剂的酸量增加时，异丁烯的转化率和三聚物的选择性也增加，但二聚物的选择性降低，四聚物的选择性则几乎没有变化。

The solvent selectivity was divided into two parts: the partial combinatory solvent selectivity and the residue solvent selectivity.

通过研究发现，在大多数情况下部分组合选择性的作用一般比较小，在选择溶剂时，可以主要考虑部分剩余选择性。

The catalytic cracking of NNJ 150 over USHY, HZSM 5 and SAPO 34 catalysts presented as that the selectivity of light olefins over USHY was the lightest among the three calalysts with a quicker deactivation, while HZSM 5 showed a longer catalyst life and lower selectivity of light olefins, for SAPO 34, both the conversion and the selectivity of light olefins were the lowest.

实现吸热型碳氢燃料这种功能的关键之一是选择适当的化学反应。由于碳氢燃料的裂化是吸热反应，而催化裂化与热裂化相比，能降低反应的温度，因此催化裂化是实现吸热型碳氢燃料功能较好的途径之一。由热力学可知，燃料裂化生成乙烯、丙

The synergistic effect of Cu and Mn is listed as follows:(1) On improving the structure of rust layer, addition of Cu and Mn can reduce cracks and pores in rust layer;(2) On altering the composition of rust, it can increase the amount of Fe3O4 and γ-FeOOH, while decrease that of β-FeOOH;(3) On the chemical state of alloying elements and selectivity of rust layer, it mainly convert the anion selectivity to canoed selectivity;(4) On the electrochemical aspect, it can decrease the anode current density and increase the corrosion potential of steel.

Cu、Mn的协同作用主要体现在以下几个方面：在改善锈层结构方面，主要是减少锈层中的裂纹与孔洞，提高锈层与基体的结合强度；在改变锈层组成方面，增加Fe3O4和γ-FeOOH的含量，降低β-FeOOH的含量；在元素化学状态与离子选择性方面，促使锈层由阴离子选择性转变为阳离子选择性，抑制Cl-的渗透；在电化学方面，大幅度降低阳极电流密度，提高钢基体的自腐蚀电位。

Under the same condition as methane partial oxidation, the reaction results are as follows: CH4 conversions is 88%, CO selectivity is 90%, H2 selectivity is 68%, CO2 selectivity is 12%.H2-TPD indicates that it is difficult for H2 to desorb from catalyst. It is estimated that the reaction between hydrogen and oxygen being absorbed is the primary approach to produce H2O, and it maybe lead to the lower H2 selectivity.

反应结果如下：CH4转化率88%；CO选择性90%；H2选择性68%，CO2选择性12%。H2-TPD实验表明，H2在催化剂表面难于脱附，表面氢与表面氧反应可能是生成H2O的主要途径，这也可能是H2选择性比较低的原因。

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。