为...的前驱

The amorphous precursor crystallises at 10008C into hexagonal anorthite before transforming into the stable triclinic form.

非晶前驱crystallises在10008C到六角钙长石之前转化为稳定的三表。

Nanosized titania particles consisting of anatase, rutile and brookite phases were synthesized under solvothermal conditions with different alcohols as solvents, hexamethylene tetramine as precipitant as well as precursor of titanium trichloride.

采用不同的醇溶剂，以六亚甲基四胺为沉淀剂，以TiCl3为前驱体，通过溶剂热的方法控制合成出纳米级的锐钛矿型、金红石型和板钛矿型的二氧化钛。

Aluminum Ispropoxide was hydrolyzed to prepare Al〓O〓 sol. The hydrolyzed 〓CHOH affected the sol peptization. The colloidal particle was the smallest when the peptization time was 12 hours.γ-Al〓O〓 membrane without cracks, thickness about 2μm, was prepared from 1M sol with a suitable amount of PVA solution. The mean pore size of the membrane was about 3nm. And, the H〓/N〓 separation factor was 3. 53, exhibiting good separation performance.

异丙醇铝为前驱体，水解制备Al〓O〓溶胶，水解产生的异丙醇影响溶胶的胶溶效果，并且胶溶12小时得到的胶粒最小。1M溶胶加PVA制备厚度2μm左右，无开裂γ-Al〓O〓膜，经600℃煅烧，平均孔径为3nm，H〓/N〓分离系数可达到3.53，表现了很好的分离性能。

Objective To explore clinical features of premonitory symptoms between familial and sporadic schizophrenics to provide bases for clinical prevention and cure.

目的 探讨家族性与散发性精神分裂症患者前驱症状的临床特征，为临床防治提供依据。

Patients had a prodrome of TIA,especially crescendo TIA.

结果22例患者中，未发现1例具有"三偏"症状，偏侧无力是最常见的症状。16例以TIA为前驱症状，尤其是上升型TIA。

In this study, SiO〓 particles with nanometer sizes were synthesized by solgel processes with TEOS as precursor.

本工作以正硅酸乙酯为前驱体，用sol-gel方法制备了纳米级SiO〓微颗粒，研究了不同sol-gel条件对SiO〓凝胶颗粒形成特性的影响和机制。

The results of the dissertation were concluded as follows:(1) It is essential to deposit a basic additive on the Mo-based catalysts for the synthesis of CH_3SH. The potassium-doped Mo-based catalysts exhibit the highest activity than that of the catalysts doped with the otherⅠA andⅡA group basic promoters. H_2-TPR and LRS characterizations suggest that the addition of a base leads to the transformation of octahedrally coordinated Mo to tetrahedrally coordinated Mo, thus leads to the split of low temperature reduction peaks. The interaction between the basic components and Mo lead to the formation of B-Mo interface phase, which are closely correlated with the formation of CH_3SH.(2) It has been found that Fe, Co, Ni and Te have evident promoting effects for the K-Mo/SiO_2 catalysts.

主要结果归纳如下：(1)在Mo基催化剂中，必须添加碱才具有可观的合成甲硫醇活性，在IA和IIA族元素中，K是最佳的碱促进剂，当K/Mo摩尔比为2，前驱体为K_2CO_3，采用共浸法制备的K-Mo催化剂活性最高。H_2-TPR和LRS表征显示，碱的加入导致表面八面体钼氧物种向四面体转化，催化剂的低温还原峰发生分裂，碱助剂与钼之间存在强相互作用形成了B-Mo"界面相"，该物种与合成甲硫醇密切相关。

Mesoporous zincum sulfide is synthesized by gentle wet chemosynthesis method, with DDA as templates and Zinc acetate and TAA as precursors. The effect to the synthesis of the ratio of reactive components, the volume of pH, reactive time and reactive temperature has been dicussed systematically, and structures of the as-synthesized samples have been characterized by X-ray diffraction, N2 adsorption-desorption, scanning electron microscopy, Fourier transform-infrared spectra, UV-vis diffuse reflectance spectroscopy, transmission electron microscopy.

以十二胺为模板，醋酸锌及硫代乙酰胺为前驱体，温和湿化学法合成了硫化锌无序介孔结构，系统研究了反应物配比、pH值、反应温度、反应时间对材料合成的影响，运用X射线衍射、N2吸附-脱附、扫描电镜、红外光谱、紫外-可见吸收光谱、透射电镜等分析手段对介孔材料的结构进行了详细的表征。

Based on " Green" chemistry , this paper mainly reviewed the latest research advance of the hydrotalcite-like materials and their derived composite oxides as an excellent solid base catalyst used in aldol condensation, Knoevenagel condensation, Michael addition, transesterification reactions and so on.

以绿色化学为基础，综述了类水滑石及其以类水滑石为前驱体衍生的复合氧化物作为一类优异的固体碱催化剂应用于醇醛缩合、克诺文诺盖尔缩合、麦克尔加成以及酯交换等反应的最新研究进展。

The results showed that the hollow nanospheres were 65 nm in sizes, which was smaller than that of the original CeO2 nanospheres. The Ce(subscript 1-x)TiO2 hollow nanospheres were face-centered cubic structure as the same as CeO2 nanospheres.

结果表明，Ce(下标 1-x)TiO2纳米空心球的粒径为65 nm，小于初始状态的CeO2纳米球，并且Ce(下标 1-x)TiO2纳米空心球的结构与前驱体CeO2晶体结构相同，均为面心立方结构。

As she looked at Warrington's manly face, and dark, melancholy eyes, she had settled in her mind that he must have been the victim of an unhappy attachment.

每逢看到沃林顿那刚毅的脸，那乌黑、忧郁的眼睛，她便会相信，他一定作过不幸的爱情的受害者。

Maybe they'll disappear into a pothole.

也许他们将在壶穴里消失