共查询到20条相似文献,搜索用时 187 毫秒
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用数值遗传算法计算配合物的稳定常数 总被引:11,自引:0,他引:11
提出了一种新的合局优化方法-数值遗传算法,该法可以处理连续变量参数的优化问题,能在很多局部较优中找到全局最优点,特别适合处理复杂的非线性问题,该法通过遗传操作不断改变个体和群体,使之逐渐适应环境,除新设计了交配和突变数值遗传操作外,本文还提出了记忆遗传操作,从而加快了运算的速度,采用这种算法,测定了新型化学发光材料的重要中间体-三氯水杨酸的酸常数及其与铜和铁的配合物的稳定常数。 相似文献
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系统研究了水溶液中磺基水杨酸与铁离子形成的3种配合物的性质,将经典无机化学实验"磺基水杨酸合铁(Ⅲ)配合物组成和稳定常数的测定"进行补充和拓展,增加了同系列配合物中另外2个有色物质组成和稳定常数测定的步骤,进而丰富了实验内容,完善了实验原理,为全面实施素质教育提供了有力的帮助。实验结果表明在强酸和缓冲溶液确立的反应条件下,铁离子与磺基水杨酸全系列配合物可以分别按比例生成,实验数据与理论组成非常吻合,这为光度法测定配合物组成,进而计算稳定常数提供了有效的手段。 相似文献
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稀土气态配合物稳定常数的钆断现象王林山王之昌(东北大学化学系沈阳110006)基于对大量稀土液相配合物的研究,前人总结出稀土配合物的稳定性与原子序数之间呈一定的规律性[1],同时也注意到由于稀土配合物的稳定常数是在水溶液中测得的,稀土离子和配体的作用... 相似文献
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His、Gly-His、Ala-His、Gly-Gly和Gly-Gly-Gly与锌、镉的配合物的稳定常数已有报道,由于不同作者的实验方法和数据处理方法不同,测定结果也不尽一致.有些数据是用手算方法进行数据处理的,求得的稳定常数可能不够精确.本工作采用文献推荐的微量pH电位滴定技术,对上述配体与Zn(Ⅱ)、Cd(Ⅱ)配合物稳定常数进行了测定. 相似文献
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铜(Ⅱ)-α-氨基酸(5-取代邻菲咯啉)-L-苏糖酸三元配合物的稳定性研究 总被引:4,自引:0,他引:4
在298K,I=0.1mol/LKNO3条件下测定了L-苏糖酸-α-氨基酸(5-取代邻菲咯啉)-铜(Ⅱ)三元配合物的生成常数.实验表明,生物配体α-氨基酸及L-苏糖酸具有良好的相容性,其三元配合物的稳定性大于相应二元配合物的稳定性.在较宽的pH值范围内,三元配合物的含量显著大于二元配合物的含量.即L-苏糖酸能作为金属离子的载体,使金属离子易于与氨基酸或蛋白质结合而被动物吸收利用.α-氨基酸及L-苏糖酸间的相容性及其三元配合物的稳定常数随α氨基酸的质子化常数及其二元配合物的稳定常数增加而增加,二者间存在良好的直线自由能关系.而在L-苏糖酸-5-取代邻菲咯啉-铜(Ⅱ)三元配合物中,由于d-p反馈π键的存在,三元配合物的稳定常数随取代邻菲咯啉质子化常数的增加而降低,二者之间也存在良好的直线自由能关系. 相似文献
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光纤探头式光度滴定法测定有机试剂及其金属配合物有关的物理化学常数曹中秋,杨建男,王忠厚,马成龙(辽宁大学化学系,沈阳110036)用普通光度法测定配合物组成、稳定常数、配合反应质子释放数以及有机试剂解离常数已有多种方法,但均需配制一系列溶液,试剂消耗... 相似文献
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联苯乙酮缩氨基硫脲合铜(Ⅱ)配合物的合成和生物活性 总被引:12,自引:0,他引:12
合成了联苯乙酮缩氨基硫脲及其与Cu(Ⅱ)的配合物,通过元素分析、摩尔电导、红外光谱和电子光谱等进行表征,证明配合物为四配位的平面正方形结构.用pH法测定了配体的质子化常数和配合物的稳定常数.抗菌活性实验表明,配体具有良好的抑菌活性,与Cu(Ⅱ)形成配合物后抑菌活性大大增强. 相似文献
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J M Cowley 《Microscopy and microanalysis》2004,10(1):9-15
Ultrahigh-resolution imaging may be achieved using modifications of the off-axis holography scheme in a scanning transmission electron microscopy (STEM) instrument equipped with one or more electrostatic biprisms in the illuminating system. The resolution is governed by the diameter of a reference beam, reduced by channeling through a line of atoms in an atomic-focuser crystal. Alternatively, the off-axis holography may be combined with the Rodenburg method in which a four-dimensional data set is obtained by recording a nanodiffraction pattern from each point of the specimen as the incident beams are scanned. An ultrahigh-resolution image is derived by computer processing to give a particular two-dimensional section of this data set. The large amount of data recording and data processing involved with this method may be avoided if the two-dimensional section is derived by recording the hologram while the four beams produced by two perpendicular biprisms are scanned in opposing directions across the specimen by varying the voltages on the biprisms. An equivalent scheme for conventional TEM is also possible. In each case, the complex transmission function of the specimen may be derived and resolutions of about 0.05 nm may be expected. 相似文献
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Determination of protein spots separated by two-dimensional polyacrylamide gel electrophoresis 总被引:1,自引:0,他引:1
A simple method for quantitating proteins in the spots on two-dimensional polyacrylamide gel electropherograms is described. The system consists in three steps: (1) O'Farrell's two-dimensional gel electrophoresis of the proteins to be analysed; (2) staining of the gels with Coomassie brilliant blue; and (3) determination of the area and integrated density of the stained spots by the Joyce Loebl Magiscan-1 image analysis system. The method can be used for the determination of proteins in the range 0.5-100 micrograms/cm2; the amount of protein involved in most spots detected by the staining method actually falls within this range. As the minimum spot diameter that can easily be handled by the method is about 2 mm, as much as 30 ng of protein in such a spot can be determined. The method can also be applied to autoradiograms. 相似文献
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J. M. Criado 《Journal of Thermal Analysis and Calorimetry》1981,21(1):155-157
The method of kinetic analysis of isothermal traces recently proposed by Dharwadkar et al. is criticized. It is concluded that this method would be a proper one in the case of reactions following the mechanism of Prout and Tompkins or Avrami-Erofeev, but it would lead to misinterpretation when diffusion or phase-boundarycontrolled reactions are involved. 相似文献
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We present a method for the mixing of fluids in a quasi two-dimensional system with low Reynolds number by means of generating a vortical flow. A two-dimensional cavitation bubble is induced in liquid-expanded phase by locally heating a Langmuir monolayer at the air/liquid interface with an IR laser. The laser-induced cavitation bubble works as a microfluidic pump and generates a thermocapillary flow around the pump. As a result, the surrounding liquid-expanded phase flows in one direction. Perturbing the thermocapillary flow with solid folds that are created by compression and reexpansion of the monolayer induces the vortical flow behind the folds. Applying the equation of creeping flow, we find a torque halfway from the center causing the vortical flow. The vorticity created in this way stretches the liquid-expanded and gaseous phase in the azimuthal direction and at the same time thins both phases in the radial direction. If the vortical flow could be maintained long enough to reach a radial thinning that would allow the interdiffusion of surfactants at the surface, then this technique would open a route for the effective two-dimensional microfluidic mixing at low Reynolds numbers. 相似文献
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完全重叠色波二维谱的解析新方法 总被引:3,自引:0,他引:3
提出一种新的完全重叠色波二维谱解析方法。对于两组分色谱-光谱数据阵,只要在重叠区中存在单组分区,就能解得各组分的纯色谱和纯光谱,这种方法将求解纯谱问题转化为优化问题,再用数值遗传算法寻找最优解.本法用于2,4-二硝基苯酚和3,5-二硝基苯甲酸的合成实验以及四环素的杂质分析都得到满意的结果. 相似文献
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Szabelski P 《Journal of computational chemistry》2008,29(10):1615-1625
Segregation of enantiomers in two-dimensional adsorbed layers is a process that is usually controlled by anisotropic directional interactions between adsorbed molecules. In this contribution, we propose a simple theoretical model in which the chiral segregation occurs even though the lateral interactions are neglected. In particular, we consider a solid surface composed of two domains with different patterns of active sites being mirror images of each other. The domains of opposite handedness represent crystal facets of a composite chiral material which are adjoined to form a heterochiral adsorbing surface. To explore equilibrium properties of the system, we use Canonical Ensemble Monte Carlo method for a square lattice. The influence of factors such as energetic properties of the surface and density of the adsorbed layer on the extent of separation is examined. The obtained results indicate that effective two-dimensional separation on the hybrid chiral surface assumed in our model can be achieved only at sufficiently low adsorbate densities. The results also suggest that the segregation on the hybrid surface would be a promising method of enantiodiscrimination for those chiral molecules which do not exhibit strong lateral interactions. 相似文献
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An improved Monte Carlo procedure is described for the evaluation of molecular integrals, which is particularly suitable for multicenter and/or two-electron calculations. The method is almost independent of the complexity of the atomic orbitals involved, and the results can be obtained with an uncertainty which is fairly adequate for most applications and with very moderate waste of computer resources. In the version presented here there is only a restriction concerned with the positive value of some functions involved, as described in the text, but this possibility does not arise in much of the practical work. An example with a two-dimensional exchange integral is worked out in detail. 相似文献
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The possible interaction models for an antifreeze protein from Tenebrio molitar (TmAFP) have been systematically studied using the methods of molecular mechanics, molecular dynamics and quantum chemistry.
It is hoped that these approaches would provide insights into the nature of interaction between protein monomers through sampling
a number of interaction possibilities and evaluating their interaction energies between two monomers in the course of recognition.
The results derived from the molecular mechanics indicate that monomerś β-sheets would be involved in interaction area and
the side chains on two p-faces can match each other at the two-dimensional level. The results from molecular mechanics and
ONIOM methods show that the strongest interaction energy could be gained through the formation of H-bonds when the twoβ-sheets
are involved in the interaction model. Furthermore, the calculation of DFT and analysis of van der Waals bond charge density
confirm further that recognition between the two TCTs mainly depends on inter-molecular hydroxyls. Therefore, our results
demonstrate that during the course of interaction the most favorable association of TmAFPs is via their β-sheets. 相似文献
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A general pre-processing procedure of the measured SAXS patterns for reducing the effect of beam stop and beam stop holder is described. A proper method for automatically choosing the regularization parameter is implemented. The method works out on the two-dimensional SAXS patterns. After deblurring, the corresponding two-dimensional patterns will be converted into one-dimensional integrated intensity distribution curves. We tested the program using both calculated artificial data and real experimental data such as polystyrene and poly(methyl methacrylate) latices. The deblurred results are satisfactory showing the effectiveness of the method. The deblurring process of a typical two-dimensional SAXS pattern using the Matlab based program can be completed in few seconds on normal personal computers. 相似文献