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151.
Abstract

A simple and sensitive spectrophotometric method is described for the determination of buclizine hydrochloride in bulk and tablets form. The method is based on the formation of charge-transfer complex between buclizine, as n-donor, and iodine, as Δ acceptor, which measured spectrophotometrically at 295 and 355 nm. A Job's plot indicated a 1:1 complex between the drug and iodine and Beer's law was obeyed in a concentration range of 4–30 μg ml?1. A more detailed investigation of the complex was made with respect to its association constant and the free energy change. The method is simple and sensitive and has been applied successfully to the analysis of laboratory-made tablets without any interference from the tablet excipients. To validate the method, the results obtained were compared statistically with a newly developed uv-derivative spectrophotometric method. The charge-transfer method was favored due to its higher sensitivity, cheap coast and available equipments.  相似文献   
152.
The electronic absorption spectra of crystals of the title componds were recorded and the experimental results were explained quantitatively with the ligand field theory and the radial wave function of bound Cu(II) cation. With these spactra, the range of magnetic interactions between two Cu(II) ions of the title compounds are discussed.  相似文献   
153.
In this paper, we directly extend the applications of the Adomian decomposition method to investigate the complex KdV equation. By choosing different forms of wave functions as the initial values, three new types of realistic numerical solutions: numerical positon, negaton solution, and particularly the numerical analytical complexiton solution are obtained, which can rapidly converge to the exact ones obtained by Lou et al. Numerical simulation figures are used to illustrate the efficiency and accuracy of the proposed method.  相似文献   
154.
This paper studies the problem of a functionally graded piezoelectric circular plate subjected to a uniform electric potential difference between the upper and lower surfaces. By assuming the generalized displacements in appropriate forms, five differential equations governing the generalized displacement functions are derived from the equilibrium equations. These displacement functions are then obtained in an explicit form, which still involve four undetermined integral constants, through a step-by-step integration which properly incorporates the boundary conditions at the upper and lower surfaces. The boundary conditions at the cylindrical surface are then used to determine the integral constants. Hence, three-dimensional analytical solutions for electrically loaded functionally graded piezoelectric circular plates with free or simply-supported edge are completely determined. These solutions can account for an arbitrary material variation along the thickness, and thus can be readily degenerated into those for a homogenous plate. A numerical example is finally given to show the validity of the analysis, and the effect of material inhomogeneity on the elastic and electric fields is discussed. Supported by the National Natural Science Foundation of China (Grant Nos. 10472102 and 10432030) and the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20060335107)  相似文献   
155.
This paper considers the wave loads on large monolithic offshore structures. The second order wave force formulae developed by Rahman and Heaps, applicable to large circular cylinders in waves, are extended to evaluate the overturning moments on large circular cylinders. The theory is then applied to square section caissons in waves, to predict the wave loads on these structures. These calculations are performed using the exact form of the second order velocity potential, φ2, with arbitrary wave number, k2, and the approximate form of φ2, with twice the value of the wave number of the first order velocity potential. The second order analytical predictions are compared with available experimental data for various ranges of wave parameters for both circular and square caissons in large amplitude waves.  相似文献   
156.
R Pratap 《Pramana》1977,8(5):447-456
We have developed a kinematical theory for the asteroidal belt and Kirkwood gaps from the point of view of stellar dynamics. We have generated the potential that would produce these gaps and have made a spectral analysis study. We have shown that these gaps could be due to spiral tubes of matter in the ecliptic plane as a consequence of differential rotation and spatial interference of density waves. We have also shown that this mechanism could account for depletion of matter from this region.  相似文献   
157.
导波法测量吸收薄膜的复介电系数和厚度   总被引:5,自引:3,他引:2  
具有吸收特性的波导薄膜,其衰减全反射(ATR)峰的位置和形状包含了薄膜诸多特征多数的信息,在同时考虑棱镜的耦合和材料的吸收的基础上,本文用一阶微扰理论推导了微扰传播常数的解析公式,并且介绍了通过分析薄膜的衰减全反射峰来计算吸收薄膜的复介电系数和厚度的方法。  相似文献   
158.
Using metal ions to control the self-assembly of metallosupramolecules of varying architecture is one of the fascinating developments in supramolecular chemistry[1,2],particularly those concerned with the deliberate construction of molecular aggregates,like helices,rotaxanes,catenanes,knots,cages[3~6] and the crystal engineering of two or three dimensional networks with varied topology and interpenetration[7~10].Coordination bonds have proved themselves to be one of the most useful connectors in supramolecular self-assembly due to their versatile geometrical modes(e.g.linear,trigonal,square plane,tetrahedral,octahedral) in bond formations.By careful design of tailored ligands,various novel supramolecular architectures have been constructed.Recently,angular bi- or tridentate and other polydentate ligands have aroused a special interest,and a variety of molecular squares,boxes and cages[1~14] with internal cavity or void have been reported,in which many nanoscale structures are formed[6,15,16].We have been interested in the construction of metal based supramolecular structures with polydentate ligands[17~20] and herein report a new metallomacrocyclic complex assembled from two linear polydentate ligands and silver(Ⅰ) nitrate.  相似文献   
159.
    
Abstract

In this study, polyethylene oxide chains have been hydrophobically end-modified with naphthalene groups (PEO-N), and water soluble ß-cyclodextrin polymers (ß-CD/EP) have been synthesized. An original associating system can be obtained by mixing these two polymers in aqueous solutions. Inclusion complex formation between the hydrophobic moieties of the PEO-N chains and the ß-cyclodextrin cavities of the ß-CD/EP polymers are at the origin of the polymolecular associations. Fluorescence anisotropy measurements allowed the determination of the complexation constants, and the onset of the polymolecular associations have been monitored by viscosimetry. The PEO chain length influence has been studied by using two molecular weights, 6000 and 20000.  相似文献   
160.
    
Abstract

Two new complexes, [Cu(SPPh3)3]2(PF6)2 (1) and [Ag2(SPPh3)2](PF6)2 (2), were prepared from [M(CH3CN)4](PF6)] (M = Cu and Ag) and triphenylphosphine sulfide ligand (SPPh3). The complexes have been characterized by elemental analysis, and UV-Vis and IR spectroscopies. Single-crystal X-ray structure analyses reveals that complexes 1 and 2 can both be described as a planar triangular configuration. Complex 1 is mononuclear and shows two crystallographically independent and chemically identical [Cu(SPPh3)3]+ cations. In binuclear complex 2, the sulfur atoms in SPPh3 adopt two different coordination modes, namely monodentate and monoatomic bridging. Luminescence properties investigation in solid state show that complex 1 revealed only one emission band at 471 nm (λex = 310 nm), which may be attributed to metal-to-ligand charge-transfer [MLCT]. However, complex 2 had two emission peaks which attributed to π–π* and n–π* transitions. Electrochemical experiment illustrated the complexes 1 and 2 represent irreversible Cu+/Cu2+ or Ag+/Ag pairs, respectively. In vitro antioxidant tests showed that the complex 2 had significant antioxidant activity against hydroxyl radicals.  相似文献   
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