查询词典 precursor

Tantalum-containing pitch as a carbon precursor was synthesized by an in situ liquid phase reaction between coal tar pitch and tantalum pentachloride.

以煤沥青为原料，氯化钽为钽源，通过化学反应制备了含钽沥青前驱体。

Also, the effects of the amount of tantalum pentachloride and reaction time on the softening point of the pitch were investigated. Results showed that the tantalum particles were dispersed homogeneously in the pitch precursor with sizes in the range of 20-50nm. The tantalum particles mainly existed in the form of δ-Ta2O5 when the reaction temperature was 420℃. By further heat treatment,δ-Ta2O5 was transformed into β-Ta2O5 at 900℃.Β-Ta2O5 and TaC co-existed at 1200℃. At 2800℃, all the tantalum was transformed into TaC.

结果表明：沥青中钽化合物的粒度为20nm～50nm，主要以五氧化二钽的形式均匀分散于沥青中；惰性气氛下，较低温度(420℃)热处理时，钽化合物以δ-Ta2O5的形式存在，温度升高到900℃时，δ-Ta2O5转化为β-Ta2O5，在温度达到1200℃时，β-Ta2O5和碳化钽共同存在于炭基体中，在2800℃温度下，钽完全转化为碳化钽。

The aim of this thesis is to prepare rutile TiO2 nanorods under the hydrothermal condition and to investigate the correlation between the preparation parameters and the photocatalytic activity of as-prepared TiO2 samples. The initial sols for TiO2 were prepared by the hydrolysis and condensation of Ti precursor, titanium n-butoxide 〔Ti4, TNB〕 in DI-water with hydrogen chloride as a peptizer.

中文摘要本研究的主要目的是制备以水热法制备金红石相二氧化钛奈米棒并探讨其制备条件与光催化活性的相关性，以四丁基氧化钛为前驱物，在盐酸的催化下，经由水热处理来合成金红石相的二氧化钛奈米粒，并藉由XRD鉴定其结晶相，TEM来观察其外观形貌及其颗粒大小，氮气吸附法来分析其比表面积。

For better understanding of the phylogenic diversity and evolution of FSH p molecule, we have isolated and sequenced the genomic sequence encoding Chinese swamp buffalo FSH p precursor molecule by PCR.

为了更好地了解FSHβ基因的进化情况，我们利用PCR方法对中国沼泽型水牛的该基因的基因组序列进行了克隆测序。

The results indicate that the pillaring process and crystal growing of anatase can be more easily realized by increasing the acid-base ratio of pillaring agents, raising the pillaring temperature and adding proper quantities of alkali. The calcination of Ti-pillared precursor brings the growth of TiO2 grain, at the same time the layer distance is declined. In order to obtain ideal products, the right pillaring conditions are: the acid-base ratio of pillaring agents of 13, pillaring temperature of 65 ℃ and the volume of alkali (2 mol/L) in pillaring liquid of 6 mL.

结果表明：在一定范围内增大柱撑剂酸碱比、提高柱撑温度以及加入适量碱，有利于插层复合反应的进行和锐钛晶型的生长；柱撑前驱物焙烧后TiO2晶粒长大，同时焙烧引起的脱水导致膨润土层间距的下降；为获得较理想的产物，合适的柱化条件为：柱撑剂酸碱比 n n (HNO3)为13、柱撑温度65 ℃和柱撑液加碱量为(2 mol/L NaOH) 6 mL。

The experimental results show that the optimum preparation conditions of catalyst of SO42-/Zr-CLC are achieved :pillaring material is 0.5mol/l ZrOCb,Zr/clay is 3mmol/g,accelerant is (NH4)2SO4 and the quantity of SO42- is 30%, the precursor of Zr-CLC is dipped by SO42- and is calcinated at temperature of 500 癈 for 2h.

将聚合羟基锆阳离子交联剂通过离子交换引入膨润土层间域撑柱膨润土，同时通过浸渍将SO42-引入到膨润土层间的锆阳离子表面，高温焙烧活化，合成了催化性能良好的中孔固体酸催化剂SO42／Zr-CLC，同时对催化剂的性能和结构进行了研究。

Based on the above experiments, the author studied the mixed metallic pillared and modified montmorillonites. The experimental result indicated that the microporous structure of Fe-Al-PLMs was affected by the changing of interlayer Fe-Al polymer with different Fe/Al ratio. But the presence of Al iron was helpful to incorporate Fe iron into interlayer of montmorillonites.. Introducing Zr helped Al-PLMs getting better larger spacing, thermal stability, surface area and pore volumes. Its successful to apply Zr-Al-PLMs to treat wastewater containing Cr iron. The experiment of modifying Al-PLMs by PVA showed that the order of adding starting materials (Al-pillaring solution, PVA, montmorillonite solution) was related to the property of Al-PLMs. The PVA as precursor was beneficial for Al to go into interlayer of the clay and to form larger basal spacing porous clay. The surface area and pore volumes of Al-PLMs increased mainly because of increasing the external surface area and mesoporous volumes after acid-activating. This conclusion confirmed that the microporous structure of pillaring clay depends upon the interlayer pillar.

实验结果表明：在Al-PLMs中引入Fe离子，不同Fe／Al比制得的Fe-Al-PLMs因层间的Fe-Al聚合离子结构不同而影响其微孔结构，但羟基Al离子的存在有利于Fe离子进入蒙脱石层间；在Al-PLMs中引入Zr离子，有助于其层间距、比表面积、孔体积增大，所得Zr-Al-PLMs应用于含Cr废水处理效果显著；PVA改性后的Al-PLMs其物化性质变化与铝柱化剂、PVA溶液、蒙脱石溶液三者不同添加顺序有关，说明PVA的前撑有利于Al进入蒙脱石层间得到较大层间距的Al-PLMs；经酸化处理得Al-acid-PLMs，其比表面积增大以外表面积为主，孔体积增大以中孔为主，这也证实了柱撑蒙脱石的微孔结构取决于其层间的柱化物。

The essence of higher heating temperature for oxalate precursor is pockety La(superscript 3+) and Zr(superscript 4+).

草酸盐前驱体中镧和锆两种成分局部的分布不均匀是造成其处理温度比氨水法要高的直接原因。

Through replacing copper Tri-fluoroacetate by copper α-methacrylic in Metal Organic Deposition process, the total amount of fluorine in YBCO precursor solution was reduced by about 50%. As a result, the calcination period for YBCO precurse film was dramatically reduced.

在金属有机盐沉积法制备YBCO薄膜的工艺中，采用无F的α甲基丙烯酸铜取代原来的三氟乙酸铜，可以降低前驱溶液中大约50%的氟含量。

Preinduction was performed using basic fibroblast growth factor, which could promote the differentiation from BMSCs into nerve precursor cells or neurons. The expression of neuroprotein molecule was coincided with the development of neural cells.

在添加化学诱导剂之前先使用成纤维生长因子进行预诱导，能促进骨髓间充质干细胞向神经前体细胞和神经元转化，且在诱导分化过程中神经蛋白分子的表达顺序与神经细胞发育过程一致。

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。