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11.
The aggregation of dansyl chloride (DNS-Cl) in acetone has been studied in detail by steady-state fluorescence techniques.It has been demonstrated that DNS-Cl is stable in acetone during purification and aggregation study processes.The aggregates are not solvolyzed in acetone,and do not take part n any chemical reactions either.It has been found that DNS-Cl tends to aggregate even when its concentration is much lower than its solubility in acetone.The aggregation is reversible,and both the aggregation and the deaggregation are very slow processes.Introduction of SDS has a positive effect upon the formation and stabilization of the aggregates. 相似文献
12.
The components of the rock, the pigments, the gold foils and the adhesive of One Thousand Hand Buddha in Dazu stone sculptures, Chongqing, China, have been analyzed by X-ray diffraction (XRD), X-ray fluorescence (XRF), infrared spectroscopy (IR), energy dispersive X-ray analysis (EDX) and fiber optics reflectance spectroscopy (FORS). Furthermore, the weathering and degeneration of One Thousand Hand Buddha have been discussed and the protective methods have been provided. In this work some useful information to study on conservation of stone relics is given. 相似文献
13.
<正>Two new eudesmane derivatives were isolated from the leaves and flowers of Verbesina virginica,along with the known 6-O-β-E -p-coumaroyl-4α-hydroxyeudesmane(1).Their structures were determined as 6-O-β-Z-p-coumaroyl-4α-hydroxyeudesmane(2) and 6-O-α-E-p-coumaroyl-1β-4α-dihydroxyeudesmane(3) by spectroscopic methods. 相似文献
14.
A novel high performance liquid chromatography-chemiluminescence(HPLC-CL) method for investigation of in vitro metabolism of repaglinide in pig liver microsomes with microdialysis sampling technique was developed.The chromatographic separation was performed on a Hypersil BDS-C18 column with an isocratic mobile phase consisting of methanol and 0.01 mol/L KH2PO4(pH 3.0)(volume ratio 75:25) at a flow rate of 1.0 mL/min.The detection was based on the chemiluminescence reaction of repaglinide with acidic potassium permanganate(KMnO4) and tris(2,2’-bipyridyl)ruthenium(Ⅲ)(Ru(bpy)33+),which was immobilized on the cationic ion-exchange resin for obtaining high sensitivity and reducing consumption of expensive reagent. 相似文献
15.
This work described a sensitive method for determination of metoprolol in rabbit plasma.The method involved purification by ultrafiltration,derivatization with fluorescein isothiocyanate,determination by capillary electrophoresis(CE) coupled with laser-induced fluorescence(LIF) detector.Other components in plasma including a variety of amino acids and proteins did not interfere with the determination of metoprolol in experimental condition.The assay had a wide range(2.0-500 ng/mL) of linearity and a detection limit of 0.8 ng/mL.The intra- and inter-day precisions were satisfactory with relative standard deviation(RSD) less than 10.0%and accuracy within 10.0%.This method was successfully applied to pharmacokinetic study of metoprolol in rabbit blood. 相似文献
16.
SHEN Yehua WANG Haibo BAI Quan & GENG Xindu Institute of Modern Separation Science Shaanxi Key Laboratory of Modern Separation Science Northwest University Xi''''an China 《中国科学B辑(英文版)》2005,(Z1)
The renaturation of the denaturedα-chymotrypsin (α-Chy) with 1.7 mol·L-1 gua-nidine hydrochloride (GuHCI) by three kinds of stationary phase of high performance hydropho-bic interaction chromatography (STHIC) with a comparable hydrophobicity but different ligand structures was investigated. The obtained result indicates that the ligand structures of the three STHIC contribute to the renaturation efficiency ofα-Chy in the order of the end ligands PEG-600< phenyl group < tetrahydrofurfuryl alcohol (THFA). 相似文献
17.
本文通过定义新的谱集,给出了算子满足a-Browder定理和a-Weyl定理的充要条件,运用了文章中新定义的谱集,研究了解析hyponormal算子的a-Weyl定理. 相似文献
18.
Jian-hua ZHANG~ Hong-ke DU Hui-xin CAO College of Mathematics Information Science Shaanxi Normal University Xi'an China 《中国科学A辑(英文版)》2007,(12)
In this paper,we introduce PropertyΠ_σof operator algebras and prove that nest sub- algebras and the finite-width CSL subalgebras of arbitrary von Neumann algebras have PropertyΠ_σ. Finally,we show that the tensor product formula alg_ML_1(?)alg_NL_2=alg_(M(?)N)(L_1(?)L_2) holds for any two finite-width CSLs L_1 and L_2 in arbitrary von Neumann algebras M and N,respectively. 相似文献
19.
Introduction Since 19541 the polymeric separation media has attracted much attention due to their chemical stability over the entire pH range. The rigid, highly cross-linked styrene copolymers were first used for chromatography by Moore.2 The macroporous copolymers currently available are not only chemically stable but also more resistant to mechanical forces prevailing in a column and therefore are comparable to the traditional packings based on silica gel. Most polymer separation media are … 相似文献
20.
Xi Huai Qiang Zhi Hui Gao Xue Chuan Wang Jian Zheng Li Hui Zong Chi Min Du 《中国化学快报》2011,22(8):985-988
Structurally simple salicylaldehyde-based fluoreseent sensors for amino acids have been obtained by one-step or two-step synthesis.These sensors show significant fluorescence enhancement in the presence of many amino acids at concentrations as low as 10~5 mol/L.The reversible reaction of the aldehydes with amino acids to form imines in aqueous solution is proposed to account for the observed fluorescence enhancement. 相似文献