活性中心

The structural and photocatalytic properties of TiO〓 as well as surface acidity were greatly improved by sulfation. SO〓〓/TiO〓 solid superacid with Hammett constant Ho less than -12.14 was prepared by treating the TiO〓 with 1.0mol. L〓 sulfuric acid solution and then calcining at 450℃ for 3h. When compared to unmodified TiO〓, the SO〓〓/TiO〓 superacid catalyst exhibited higher anatase content, smaller crystal size, higher specific surface area, centralized pore size distribution, and the blue-shifted band edge of uv-vis adsorption spectra. Furthermore, the SO〓〓/TiO〓 superacid also showed excellent reaction activity and stability for CH〓Br photocatalytic decomposition even under the moist reaction conditions. The apparent quantum efficiency of SO〓〓/TiO〓 was 10 times of that of TiO〓 catalyst for the photocatalytic degradation of bromomethane. Therefore, the SO〓〓/TiO〓 superacid catalyst is promising for practical application in environmental remediation.It was found that both L and B acid sites exist on SO〓〓/TiO〓 photocatalyst while only L acid sites on TiO〓 photocatalyst. On the basis of experimental results, the synergistic model of superacidic centers was proposed for SO〓〓/TiO〓 photocatalyst to explain the photocatalytic behavior and the mechanism of superacidifing effects, assuming that the adjacent L and B acid sites induced by SO〓〓 comprise cooperatively the superacidic center on superacid photocatalyst. The group cooperation of the superacidic center could strengthen the surface acidity, increase surface acid sites and the adsorbtion of O〓, promote separation of photogenerated electron-hole pair, enhance the interfacial transfer of charges and reversibility of water adsorption. Consequently the excellent photocatalytic activity, reaction stability and resistibility to humidity of SO〓〓/TiO〓 superacid photocatalyst may attributed to the group cooperated effect of the superacidic center on the photocatalyst.

研究结果表明：SO〓〓与TiO〓表面的结合为螯合式双配位结构；TiO〓光催化剂表面经H〓SO〓浸渍处理后，提高了表面酸性，改善了催化剂结构和光催化性能，当H〓SO〓浸渍浓度为1.0mol.L〓、烧结温度为450℃时，可制得SO〓〓/TiO〓超强酸催化剂(H〓＜-12.14)，其结构和光催化活性得到明显改善，与TiO〓相比，SO〓〓/TiO〓光催化剂的锐钛矿含量高、晶粒小、BET比表面积大、孔径分布集中、光谱吸收边蓝移，具有优异的光催化氧化活性、稳定性及抗湿性能，光催化降解溴代甲烷的表观量子效率比TiO〓催化剂提高了一个数量级，是一种有实际应用前景的高效光催化剂；由此提出了SO〓〓/TiO〓超强酸催化剂表面集团协同作用的超强酸中心模型，认为在SO〓〓/TiO〓超强酸催化剂表面，由SO〓〓诱导的相邻L酸中心和B酸中心组成了集团协同作用的超强酸中心，其集团协同作用显著地增强了催化剂表面酸性、增大了表面酸量及O〓吸附量、促进了光生电子和空穴的分离及界面电荷转移，具有可逆吸附水的性能，是SO〓〓/TiO〓超强酸催化剂具有优异的光催化氧化活性、很好的活性稳定性及抗湿性能的重要原因。

The oxidation of naphthols and 2-naphthylamine under the copper amine complexes led to some novel reactions and products.

本文利用简单易得的小分子有机胺与铜盐制成络合物，模拟氧化还原酶，通过改变铜胺配比等因素来调整催化剂活性中心的配位状态，从有机合成的角度研究其对萘酚类和2-萘胺等底物的氧化性质和催化氧化性质，发现了一些新颖的仿生氧化反应和产物。

This thesis took the complexes of cupric or cuprous salts with small molecular amines to mimic oxidoreductases. The coordination environment of the active centers of the catalysts can be modified by changing the ratio of copper/amine. The oxidation of naphthols and 2-naphthylamine under the copper amine complexes led to some novel reactions and products.

本文利用简单易得的小分子有机胺与铜盐制成络合物，模拟氧化还原酶，通过改变铜胺配比等因素来调整催化剂活性中心的配位状态，从有机合成的角度研究其对萘酚类和2-萘胺等底物的氧化性质和催化氧化性质，发现了一些新颖的仿生氧化反应和产物。

He advancement of direct partial oxidation of methane to syngas over transition metal catalyst s was reviewed.

综述了过渡金属催化剂催化甲烷直接部分氧化制合成气反应的进展，讨论了关于催化剂活性中心的一些观点和两种有代表性的反应机理。

Investigation status and novel advances on Cu-based catalyst for methanol synthesis from syngas are summarized in this paper.

概述了以合成气为原料合成甲醇反应中铜基催化剂的研究现状和最新进展，其中分别讨论了铜基催化剂的制备方法、助剂、活性中心以及甲醇合成的机理和动力学等方面内容。

Selenium is an active center of many enzymes essential trace element selenium in the human body.

硒是多种酶的活性中心硒是人体必需的微量元素。

It is proposed that tyrosine residues are involved in the active site of CTA and they are crucial in recognition and binding of ribosomal RNA.

这些结果表明酪氨酸残基可能位于cinnamomin A链的RNA N-糖苷酶活性中心，并且它们在识别和结合核糖体RNA的过程中有重要作用。

Obviously, different structures and properties of the active center of these heme proteins lead to different reactivities and natural functions, and the primary difference is the interaction between the protein peptide chain and the heme group.

显而易见，血红素类蛋白质分子活性中心结构和性质的差异导致了它们不同的反应功能，非常重要的原因在于不同的蛋白质分子中多肽链和血红素辅基的相互作用形式不同。

By the Tyndall effect, TEM observation and ultrafiltration experiment, FeCl 3 Al 3 phen catalyst is proved as a colloidal disperse system in butadiene hydrogasoline solution.

通过Tyndal效应、电镜观察和超过滤实验表明，FeCl3－Al3－Phen催化剂在溶有了二烯的加氢汽油介质中为胶体分散系，活性中心位于胶粒表面，因此是胶体催化剂。

Single component and multi\|component of iron system colloidal catalyst \Ali\|Bu\-3CH\-2CHCH\-2Cl\ were mixed by different ratios in hydrogenated gasoline medium at 25℃.This paper studied the relationship between the nonaqueous systematic electroconductivity and the concentration of catalyst components.In combination with Tyndall effect,polymerization experimental results,Ali\|Bu\-3 existed in associated state and dissociated into ionpair.The reaction between Ali\|Bu\-3 and Fenaph\-2 was the main reaction which formed colloidal core.Ali\|Bu\-3 reacted on CH\-2CHCH\-2Cl and Ali\|Bu\-2Cl was yielded which joined the formation of active center on the surface of colloidal core.The excessive Ali\|Bu\-3 was dissociated into ionpair which formed double electrode layer,and the double electrode layer kept the colloidal particles relatively stable.

研究了在25℃加氢汽油介质中，铁系胶体催化剂［Fenaph2Ali-Bu3―CH2==CHCH2Cl］单组分、多组分按不同配比混合，非水体系电导率与浓度的关系，结合Tyndall效应，聚合实验结果，得出Ali-Bu3以缔合状态存在并解离成离子对它同环烷酸亚铁的作用是形成胶核的主要反应，与氯丙烯反应生成的氯化异丁基铝，在胶核表面参与形成活性中心由过量Ali-Bu3解离的离子对形成的双电层结构，使胶粒保持相对稳定。

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％。