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171.
本文用两种方法制得硝酸钆的低水合物Gd(NO_3)_3·5H_2O、Gd(NO_3)_3·3.5H_2O,其中Gd(NO_3)_3·3.5H_2O是文献中尚未报道的 ,给出了它们的M.P.和X-衍射特征值。  相似文献   
172.
对氯柱硼镁石(2MgO•2B2O3•MgCl2•14H2O)在4.5%H3BO3水溶液40 ℃的溶解及相转化过程进行了动力学研究.对不同时间取出的液相的化学分析及不同阶段分离固相的鉴定结果表明,该复盐在溶解阶段出现与前所报导不同的同步溶解,最终产物是库水硼镁石(2MgO•3B2O3•15H2O).提出了库水硼镁石的形成条件和溶解及相转化动力学机理,利用单纯形优化法配合Runge-Kutta微分方程组数值解法对实验数据进行处理,给出了转化结晶动力学方程.  相似文献   
173.
A convergent selective route to (+)-brefeldin A (BFA) and 7-epi-BFA was developed, with the crucial C-4/C-5 stereogenic centers were established using Crimmins asymmetric aldolization.  相似文献   
174.
Ming Z. Gao 《Tetrahedron letters》2004,45(29):5649-5652
The novel structures of sulfur-containing chiral bis(oxazoline) compounds which have been synthesized have been determined by X-ray crystal diffraction analyses. A high enantioselectivity (ee >99%) in the asymmetric cyclopropanation of diphenylethene with diazoester using the bis(oxazoline)-Ru(II) catalyst was obtained.  相似文献   
175.
Double C-C bond cleavage of a cyclopentadienyl ligand proceeded to titanacyclopentadienes when 2 equiv of nitriles were added and the resulting two-carbon unit and three-carbon unit were converted into a benzene derivative and a pyridine derivative, respectively, in one-pot.  相似文献   
176.
The activity of Mg−Al basic heterogeneous catalysts in the reactions of alcohols with ethylene oxide was studied. The kinetics of alcohol oxyethylation was examined. The kinetic equation of the reaction was determined and the structure of products was studied. The distribution coefficients of the oxyethylation reaction products were calculated. A comparison of the catalytic activity of Mg−Al hydroxides and products of their thermal treatment was made.  相似文献   
177.
A one-step pathway has been adopted to fabricate biodegradable polylactide (PLA) hollow spheres by interfacial polymerization in an oil-in-water emulsion system. The mechanism of sphere formation is suggested with respect to interfacial cross-linking polymerization and subsequent precipitation of the unreacted PLA macromonomers onto the preformed shells. Their hollow nature and morphology were verified by transmission electron microscopy and scanning electron microscope characterizations.  相似文献   
178.
本文首次将亚硫酸钠化学除氧技术应用于β-环糊精诱导室温燐光(β-CD-RTP)法中,除氧简便快速(1~1.5min),测定了痕量二氢苊、芴、菲、7,8-苯并喹啉。1,2-二溴乙烷作重原子微扰剂,其用量减少到每10mL中5μL,体系基本澄清,pH≈6.8,分析特性优于通氮除氧技术所得结果。  相似文献   
179.
Ternary terbium complexes with p-aminobenzoic acid (HL), [TbL3(DMSO)(H2O)]2 (1), [TbL3(DMF)(H2O)]2 (2) and [TbL3(Bpy)(H2O)]2·2H2O (3) (DMSO=dimethyl sulfoxide, DMF=N, N- dimethylformamide, Bpy=2, 2′- bipyridyl) have been synthesized, and their crystal structures determined. The luminescence properties of these complexes, including both the emission quantum yield and the fluorescence lifetime, have been investigated. The effect of a second ligand on the crystal structure and luminescence property of the ternary terbium p-aminobenzoic acid complexes, and the relationship between luminescence properties and crystal structure, including coordination mode of the L ligand and the characteristics of a second ligand, are discussed.  相似文献   
180.
Quantum dots (QDs) were prepared in an organic system through a simple and low-cost wet chemistry method. Polymer beads with a diameter of 60–70 nm and specific functional groups were synthesized by a particular seeded emulsion polymerization technique. QDs were embedded in the polymer beads with the specific functional groups through dissolving and swelling method, which provided the condition for the conjunction of biomolecules and QDs as fluorescent probes. The prepared composites were characterized with UV-Vis, PL, TEM, FTIR, CLSM and conductance titration etc. The results show that QDs are successfully embedded in polymer beads, which breaks the limitation that the conjunction of biomolecules and QDs can be achieved only for those synthesized in aqueous system. __________ Translated from Journal of Shanghai Jiaotong University, 2005, 39(1) (in Chinese)  相似文献   
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