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131.
Wen Xu Guoqun Liu Gang Xue Wentao Yu 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(8):m436-m438
The crystal structure of the title compound, (C16H36N)[Ni(C3S5)2], is isomorphous with that of the corresponding Pt complex but different from the structures reported for compounds of the same chemical composition, and so provides a new crystalline phase of this complex. The nickel complex anion has good planarity and lies on a crystallographic inversion centre. There is disorder in the two terminal C atoms of two of the butyl chains of the tetra‐n‐butylammonium cation, the N atom of which is located on a twofold axis. 相似文献
132.
Xue Yuan HU Xue Sen FAN Xin Ying ZHANG Gui Rong QU Yan Zhen LI School of Chemical Environmental Sciences Henan Key Laboratory for Environmental Pollution Control Henan Normal University Xinxiang Chongqing University of Medical Sciences Chongqing 《中国化学快报》2005,(7)
Construction of tetrahydropyran rings has attracted a great deal of interests in organic synthesis in recent years1, since tetrahydropyran moiety constitutes a structural unit in a number of natural products2. In addition, tetrahydropyran derivatives possess wide range of biological activities and pharmacological properties, such as anticancer activity3 and antihypersensitivity4. Many methods for the preparation of such compounds have already been developed5. Among them, condensation of α, β… 相似文献
133.
Swelling and network parameters of crosslinked thermoreversible hydrogels of poly(N-ethylacrylamide)
Samples of Poly(N-ethylacrylamide) (PEA) have been synthesized by free radical polymerization in water using N,N′-methylene bis-acrylamide (BIS) as crosslinker. Hydrogels obtained by swelling them in water, 15 wt% KCl and 1 wt% sodium dodecyl sulphate (SDS) were examined by gravimetric, dimensional and compression-strain measurements to afford values of swelling ratio, polymer-solvent interaction parameters, elastic moduli and effective crosslinking density νe. Crosslinking inefficiency is evidenced by the low value (0.23) of νe relative to the theoretical crosslinking density νt based on the content of BIS in the synthesis. A small but finite extrapolated value of νe at νt = 0 is indicative of hydrophobic physical interactions. In water at 298 K increasing the content of BIS leads to a decrease in swelling and increases in values of elastic moduli and polymer-water interaction parameter. At a fixed content of BIS the values of νe and the elastic moduli exhibit an unusual increase with temperature, the crosslinking thus being thermally reversible. It is proposed that this results from a balance between hydrophobic interaction and breakage of hydrophilic hydrogen bonding. Although KCl in the medium decreases the swelling compared with that in water, the opposite effect occurs on incorporation of SDS, which is assumed to confer some polyelectrolyte character to the PEA chains. The finding, that these two swelling media reduce the values of νe and elastic moduli cf the value in water, has not been resolved satisfactorily. 相似文献
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用硅胶-氧化铝柱色谱预分离和色谱-质谱分析研究了两种褐煤超临界流体抽提物中脂肪烃馏分组成结构特征。结果表明,除主要成份正构烷烃(C_(13)~C_(33))外,尚有少量的类异戊二烯烃(姥鲛烷、植烷等)和萜烷。其中萜烷以五环三萜为主(C_(27)、C_(29)~C_(32)藿烷类化合物),并有一定量的C_(27)、C_(29)和C_(30)藿烯,倍半萜和三环二萜烷含量很少。未检出甾烷。此外,还检出一完整系列的烯烃。试验结果表明,超临界流体抽提条件对褐煤抽出物各组分、含量及其分布有一定的影响。 相似文献
138.
The high-sensitivity determination of protein concentrations by the enhancement of Rayleigh light scattering of Arsenazo-DBN 总被引:1,自引:0,他引:1
A new Rayleigh light scattering (RLS) assay of protein is presented in this paper. At the optimum pH 4.10, the weak RLS of Arsenazo-DBN can be greatly enhanced by the addition of proteins due to the interaction between protein and Arsenazo-DBN. Based on this, the reactions of Arsenazo-DBN and proteins, including bovine serum albumin, human serum album, gamma-globulin, egg albumin, lysozyme and trypsin, were studied. A new quantitative determination method for proteins has been developed. The linear range for human serum albumin, for example, is 0.085-34.62 micrograms mL-1 with a detection limit of 44.8 ng mL-1. Besides high sensitivity, the method is characterized by good reproducibility, rapidity of reaction, good stability, and few interfering substances. The determination of the proteins in human serum and urine samples by this method give results very close to those obtained using Coomassie Brilliant Blue G-250 colorimetry, with relative standard deviations of 0.7-2.5%. 相似文献
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皮革中六价铬含量的IUC-18测定法 总被引:4,自引:0,他引:4
Cr(III)是制革业最重要的鞣剂 ,制革业所用的Cr(III)鞣剂由Cr(VI)还原而得到。皮革中除Cr(III)外 ,还可能含有微量的Cr(VI) ,目前欧盟等国要求Cr(VI)的含量小于 5mg/kg[1 ] ;国内则还没有分析测定皮革中六价铬的国家标准 ,本文介绍六价铬的IUC - 1 8国际标准分析方法 (IUC ,Inter nationalUnionofChemistry) ,并分析了该方法的不足及改进途径。1 实验部分pH7 5~ 8 0、惰性气体保护下用磷酸盐缓冲溶液浸取皮革的六价铬 ,六价铬将 1 ,5 二苯卡巴肼氧化为 1 ,5 二苯… 相似文献