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991.
The title complex 1·THF has been synthesized by the reaction of [HO-4,6-di-tBu- C6H2-2-CH2{CH(iPrNCHCHN)}]Cl with NdCl3 in a 2:1 molar ratio in THF, and characterized by single-crystal X-ray diffraction. It crystallizes in monoclinic, space group P21/c with a = 9.6501(14), b = 16.393(2), c = 36.745(6) , β = 97.444(4)o, V = 5763.7(15) 3, Mr = 1124.69, Z = 4, Dc = 1.296 g/cm3, μ(MoKα) = 1.175 mm-1, F(000) = 2348, the final R = 0.0729 and wR = 0.1762 for 8735 observed reflections with I > 2σ(I). Complex 1 consists of an anion [NdCl5(THF)]2- and two cations [HO-4,6-di-tBu-C6H2-2-CH2{CH(iPrNCHCHN)}]2 to form a layer structure by the interconnection of anions and cations via hydrogen bonding. The central metal Nd in the anionic unit is coordinated by five Cl atoms and one oxygen atom from solvated THF molecule assuming a distorted octahedral geometry. 相似文献
992.
SURFACE OF GELATIN MODIFIED POLY(L-LACTIC ACID)FILM 总被引:1,自引:0,他引:1
In this paper, the surface structure of poly(L-lactic acid) (PLLA) film modified with gelatin was investigated. ThePLLA film specimens were treated directly with aqueous alkali solution to provide their surfaces with carboxyl groups, sothat these functional groups could become the reactive sites for gelatin immobilization. The functional groups of the PLLAfilms were identified by ATR-FTIR spectra and XPS spectra, the changes in surface morphology were observed by usingenvironmental scanning electron microscopy (ESEM), and the hydrophilicity of modified PLLA films was examined bywater contact angle measurement. Experimental results showed that the gelatin was immobilized with water-solublecarbodiimide (EDC) onto the PLLA film's surfaces, and the gelatin content on the polymer surface was related to carboxylicgroup formed in the controlled hydrolysis process. Rough surfaces caused by hydrolysis will predominantly favor the adhesion and growth of cell; and the hydrophilicity of these surfaces after the modification procedure is enhanced. 相似文献
993.
994.
995.
氢化物发生—光度分析法连续测定砷锡 总被引:4,自引:0,他引:4
锗、砷、锡、锑等性质相近元素在用普通分光光度法测定时,存在着选择性差的问题,为实际分析及连续测定造成了困难。共价氢化物发生-银溶胶光度分析体系的建立和发展,基本解决了此类元素的选择性问题,也为同时或连续测定创造了条件。本文在原工作的基础上,借助于AsH_3和SnH_4在形成酸度上的差异,在高酸度(3.0mol/L HCI)溶液中使砷离子转变为AsH_3逸出分析后,再调节至微酸性(pH 4.5,CH_3COOH-CH_3COONa)产生SnH_4,而显色测定, 相似文献
996.
双(1,2—二芳基—1,2—二硫代乙烯)镍配合物合成及光稳定作用 总被引:2,自引:0,他引:2
合成了通式为Ni(RCSCSR’)2的6个配合物,这些配合物可由对称或不对称安息香中间体制得。讨论了它们对多甲川菁染料HITCI的光稳定作用,发现含镍配合物的染料溶液光退色速度低于不含镍梧合物浓工。 相似文献
997.
The synthesis of photochromic compounds has received a great deal of attention because of their potential application in various areas such as optical information storage[1—5], photoswitches and molecular recognition[6—8]. One of the most important researches in this field is the synthesis of a variety of photochromic fulgides to establish basic correlation between their molecular structures and photochromic properties. Since 1978, Heller[9] firstly reported the synthesis of the heterocyclic… 相似文献
998.
Spectral feature channels are selected based on the optimization theory and by makinguse of Shannon's formula with main effective wavenumber regions ranging from 1600 cm~(-1)to 400 cm~(-1). Ten characteristic codes are sufficient for retrieving a spectrum using the spec-tral data re-compressed in the selected channels. Results of retrieving 50 substances includ-ed in the databank show that the accuracy and the precision of the system are 1.00 and 0.85respectively. Results of retrieving substances not included in the databank show a credibleinterpretative capacity of the system. The average time for retrieving a spectrum is ca.0. 98s. 相似文献
999.
形状记忆高分子材料(shape memory polymers,SMPs)作为一种特点突出、性能优良的智能材料具有极高的研究和实用价值,受到各国研究人员的广泛关注,新的制备方法和材料体系不断涌现,显示出巨大的发展潜力.本文总结了近年来出现的以共混方式为基础的多种重要制备方法,包括聚合物与聚合物直接熔融共混、溶液共混、借助增容剂或交联剂进行共混、通过新型微层共挤出技术进行交替层状共混、以及利用静电纺丝技术进行三维网络结构共混等.相较于化学合成方法,这些共混方法具有操作简单、原料易得、制备效率高、产品性能调节方便、制备过程更为环保等优点,并且能够得到与化学合成方法性能相同甚至更好的产品,优势突出,是今后制备形状记忆高分子材料的一大趋势.本文从这些新型共混材料的制备过程、微观结构、形状记忆性能等角度详细分析了不同方法的特点和优势.这些近年来出现的共混制备方法对于形状记忆高分子材料的发展和未来应用将是至关重要的. 相似文献
1000.