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991.
采用连续小波变换(CWT)对光谱数据进行处理,用独立成分分析(ICA)进行特征提取,再用回归分析方法对被测组分进行测定,建立了连续小波变换一独立成分回归(CWT-ICR)方法。方法用于肉样品中水分、脂肪和蛋白质多组分的同时测定,所得结果与化学法测得结果相符。  相似文献   
992.
用化学键参数-模式识别或人工神经网络方法研究MeX-REX_3型熔盐相图,总结中间化合物的形成、化学配比和Me_3REX_6型化合物同分或异分熔化规律,并对其熔点或分解点进行预报.  相似文献   
993.
Six novel pyrromethene BF2 complexes,of which five compounds have not been reported,were synthesized and characterized.Their relationships between st ructure and photophysical behavior were studied with the aid of fluorescence and triplet state absorption spectra.The results indicate that,compared to 8 alkyl pyrromethene BF2 complexes,the compounds containing 8 aryl exhibit high fluore scence quantum yield and rather low triplet state absorption.  相似文献   
994.
水凝胶是一种亲水性聚合物网络,可以溶胀大量水,其物理性质接近软组织.光聚合与传统的聚合方法相比,具有反应速率快、反应条件缓和、反应放热低等特点.因此,光聚合水凝胶广泛应用于生物医学领域.本文介绍了光聚合水凝胶材料,并详细论述了光聚合水凝胶在药物释放体系、组织工程支架材料、细胞受控生长、细胞微囊化和可注射水凝胶等方面的应用.可以预见光聚合水凝胶作为生物材料在组织工程及再生医学领域中具有良好的应用前景.  相似文献   
995.
近年来,大量研究表明,利多卡因的代谢物单乙基甘氨酰二甲苯胺(MEGX)的生成速率及含量变化与肝脏贮备功能密切相关,所以,MEGX试验(MEGX test)目前被广泛用于临床和药理学实验,评估肝移植时供肝的贮备功能,以及各种因素对肝脏生物转化功能的影响.测定60 min时的MEGX血药浓度比测定利多卡因更有临床意义.  相似文献   
996.
Both the denaturation, as followed by UV absorbance and fluorescence changes, and inac-tivation of creatine kinase in guanidine solutions have been found to be first order reactions.In 3 M guanidine, at 30℃, the inactivation rate constant was found to be 5.9 sec~(-1) and thedenaturation rate constant 1.9 sec~(-1). At lower guanidine concentrations, the inactivation rateconstants were only little affected whereas the denaturation rate constants decreased markedly,being of the order of 0.04 in 1 M and 0.004 in 0.5 M guanidine. The kinetics of the inactiva-tion reaction in 0.5 M guanidine was found to be in agreement with a combination of two firstorder reactions. The enzyme lost activity first by a fast reaction with a rate constant onlyslightly lower than the rate constant in 3 M guanidine followed by a slower reaction with a rateconstant of 0.003 sec~(-1). In 0.3 M guanidine, very little change in either UV absorbance or influorescence was observed, but, in sharp contrast, the enzyme lost considerable activity by a fastreaction and this was followed by a slower reaction of inactivation. Even after prolongeddenaturation in 0.5 and 0.3 M guanidine, residual activities of 3.4% and 30% remained res-pectively. The above results suggest a very fragile active site although dissociation of thedimer and reversible guanidine inhibition may also contribute to the initial rapid inactiva-tion. It is also to be noted that the multiphasic courses of inactivation at lower guanidineconcentrations seem to suggest the presence of partly active intermediates during denaturation.  相似文献   
997.
手性识别及氨基酸类手性固定相的研究进展   总被引:6,自引:0,他引:6  
近年来, 手性识别更加凸现出极其重要的现实意义, 而作为分离手性分子应用的手性固定相自然引起了大家的关注.立足于国内外手性固定相的研究成果, 介绍了手性固定相及其分类, 并重点综述了基于氨基酸的手性固定相的发展及其制备方法. 同时, 简要介绍了作为手性固定相对不同异构体的识别机理.  相似文献   
998.
姚海生  张金国  徐凡  沈琪  张勇 《结构化学》2007,26(12):1391-1394
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   
999.
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   
1000.
姚金水  吴佑实 《有机化学》2002,22(2):101-106
综述了催化不对称硅氢化反应的研究进展情况,重点介绍了最近十年来手性催 化剂配体的研究情况。  相似文献   
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