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51.
高效毛细管电泳是近年来分离科学中发展最为迅速的方法之一.它具有分离效率高、所需样品量极少、适合于生物大分子的分离测定和自动化程度高等特点.在毛细管电泳中,区带电泳作为主要的分离模式发挥了重要的作用[1].本文中以麦芽寡糖类物质为对象,研究了离子流体动力学半径在分离中的作用和规律,提出了麦芽寡糖的迁移时间、淌度与其所含糖基数目的线性关系,并在不同的体系与操作电压下得到了验证.同时,也为利用毛细管电泳技术估算麦芽寡糖所含糖基数提供了简易的途径.1实验部分自行组装毛细管电泳电化学检测系统,高压电源0~30k… 相似文献
52.
This research examines and quantifies the influence of ion solvation parameters on the affinity of monovalent anions for strong-base anion resins. A data set comprising resin selectivity coefficients and solvation parameters from the literature is statistically analyzed using correlation and multiple regression techniques. The affinity of monovalent anions for the resin phase correlated well to ionic radii. Solvation parameters such as the hydration number, and entropy, enthalpy and free energy of hydration are also strongly correlated to selectivity. Using the stepwise regression procedure on subsets of independent variables, the entropy of hydration, which characterizes the structure-influencing nature of ions in solution, is incorporated as the sole parameter in the predictive model for resin selectivity. The data are best correlated by the exponential form of the regression equation, and the physical meaning of the correlation is shown to be reasonable. A simple rule for categorizing ions as structure-makers and structure-breakers is proposed, and the results are consistent with conventional classifications. 相似文献
53.
Bei-sheng Kang Mao-chun Hong Ting-bin Wen Han-qin Liu Jia-xi Lu 《Journal of Cluster Science》1995,6(3):379-401
Simple fragments of transition metal 1,2-bidentate thiolates, the so-called building blocks of the general compositions ML3, ML2, ML, M(O)L2, ML2L, MLL, etc. have been proposed to constitute the di-, tri- and tetranuclear complexes concerned in this review. Structureal regularities and characteristics have been discussed and summarized according to the thiolato ligands edt and pdt, bdt and tdt, mp, and mpo, and mpp, respectively.Abbreviations H2mpo
o-mercaptophenol
- Hmpo
2-mercaptopyridine-N-oxide
- R2dtc
N,N-dialkyldithiocarbamate
- Haet
2-aminoethanethiol
- H2bdt
o-benzenedithiol
- H2pdt
1,2-propanedithiol
- H2tdt
toluene-3,4-dithiol
- Hmpp-mppH
bis-(3-hydroxy-2-pyridyl)disulfide
- Hmp-mpH
bis-(2-oxyphenyl)disulfide
- H2edt
1,2-ethanedithiol
- dppe
1,2-bis(diphenylphosphino)ethane
- H2tedt
3,4,5,6-tetrachlorobenzene-1,2-dithiol
- H2tpdt
3-thiapentane-1,5-dithiol
- H2mnt
maleonitriledithiol
- Him
imidazole
- Bz
benzyl
- py
pyridine 相似文献
54.
Anjali Acharya A. Goswami P. K. Pujari S. Sabharwal S. B. Manohar 《Journal of polymer science. Part A, Polymer chemistry》2002,40(8):1028-1036
Positron annihilation lifetime spectroscopy was used to characterize the reentrant volume‐phase‐transition behavior of poly(N‐isopropyl acrylamide) hydrogel in an ethanol/water mixed solvent. The polymer gel was synthesized with γ irradiation. The ortho‐positronium lifetime (τ3) in the gel slowly increased with an increase in the ethanol content in the mixed solvent. τ3 was not influenced by the volume phase transition. The ortho‐positronium intensity decreased with the collapse of the gel in an approximately 10% ethanol/water mixture. When swelled in pure ethanol, τ3 initially increased with the solvent amount in the gel, showing the destruction of intramolecular hydrogen bonding and the relaxation of polymer chains. The lower critical solution temperature of the gel in the 10% ethanol/water mixture was lower than that in pure water, and τ3 for various solvent contents showed behavior similar to that seen in pure solvent. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1028–1036, 2002 相似文献
55.
56.
Light-stable micelles with azo dyes were prepared by micelle formation of a nonamphiphilic diblock copolymer containing azobenzene and UV absorbent at ca. 1 mol% as the unit ratios. The nonamphiphilic block copolymer consists of two different kinds of random copolymer blocks: poly[4-(phenylazophenoxymethyl)styrene-co-vinylphenol] (P(AS-co-VPh)) and poly[4-(2-hydroxybenzophenoxymethyl)styrene-co-styrene] (P(HBS-co-St)). This random block copolymer, P(AS-co-VPh)-b-P(HBS-co-St) formed the micelles in the presence of 1,4-butanediamine (BDA) through hydrogen bond cross-linking between the VPh units via BDA. The micelles had the azobenzene moieties at the cores and the UV absorbents at the coronas. The micelles showed a small color difference in color fading experiments, in comparison with the unimers and with micelles having no UV absorbent at the coronas. It is significant that the diblock copolymer forms the micelles and has the UV absorbents at the coronas to suppress the color fading. Furthermore, the chain length of ,-diamines had no effect on the hydrodynamic radius of the micelles, but affected the aggregation number and the cmc. 相似文献
57.
Jin Chen Lin-xi Zhang A-gen Xia 《高分子科学》2006,(1):13-19
It is important to know the rate of intra-molecular contact formation in proteins in order to understand how proteins fold clearly. Here we investigate the rate of intra-molecular contact formation in short two-dimensional compact polymer chains by calculating the probability distribution p(r) of end-to-end distance r using the enumeration calculation method and HP model on two-dimensional square lattice. The probability distribution of end-to-end distance p(r) of short two-dimensional compact polymers chains may consist of two parts, i.e. p(r) = p1(r) p2(r), where p1(r) and p2(r) are different for small r. The rate of contact formation decreases monotonically with the number of bonds N, and the rate approximately conforms to the scaling relation of k(N) ∝ N-α. Here the value of α increases with the contact radius a and it also depends on the percentage of H (hydrophobic) residues in the sequences of compact chains and the energy parameters of εHH, εHP and εPP . Some comparisons of theoretical predictions with experimental results are also made. This investigation may help us to understand the protein folding. 相似文献
58.
《Optimization》2012,61(6):787-798
In this paper we suggest an approach to regularity in, vector optimization which extends the one given in [9]; some necessary or sufficient regularity conditions are given for a wide class of nondifferentiable vector optimization problems which embraces the convex ones. 相似文献
59.
Luis Escauriaza 《偏微分方程通讯》2013,38(5-6):821-845
It is shown that any elloptic or parabolic operator in nondivergence form with measurable coefficients has a global fundamental solution verifying certain pointwise bounds. 相似文献
60.