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131.
本文综述了利用多种不同的天然生物分子如蛋白质(包括酶和氨基酸)、糖类、核酸、多巴胺和柠檬汁等为模板合成导电聚苯胺的研究进展。本文首先介绍了这些天然生物分子对产物聚苯胺的手性、导电率、形态以及其它方面性质的影响,归纳了利用天然生物分子合成导电聚苯胺的研究进展,然后分析了导电聚苯胺合成过程中面临的问题并对该领域的未来发展进行了展望,以期为制备性质优良和环境友好的新型导电聚苯胺材料提供有益的参考。 相似文献
132.
We prove that certain two-point Padé approximants occupying the diagonal of the Padé table form monotone sequences of lower and upper bounds uniformly converging to a Stieltjes function. The results can be applied to the theory of inhomogeneous media for the calculation of the bounds on the effective transport coefficients of heterogeneous materials. 相似文献
133.
Hydraulic conductivity of rock fractures 总被引:26,自引:0,他引:26
The flow of a single-phase fluid through a rough-walled rock fracture is discussed within the context of fluid mechanics. The derivation of the cubic law is given as the solution to the Navier-Stokes equations for flow between smooth, parallel plates - the only fracture geometry that is amenable to exact treatment. The various geometric and kinematic conditions that are necessary in order for the Navier-Stokes equations to be replaced by the more tractable lubrication or Hele-Shaw equations are studied and quantified. In general, this requires a sufficiently low flow rate, and some restrictions on the spatial rate of change of the aperture profile. Various analytical and numerical results are reviewed pertaining to the problem of relating the effective hydraulic aperture to the statistics of the aperture distribution. These studies all lead to the conclusion that the effective hydraulic aperture is less than the mean aperture, by a factor that depends on the ratio of the mean value of the aperture to its standard deviation. The tortuosity effect caused by regions where the rock walls are in contact with each other is studied using the Hele-Shaw equations, leading to a simple correction factor that depends on the area fraction occupied by the contact regions. Finally, the predicted hydraulic apertures are compared to measured values for eight data sets from the literature for which aperture and conductivity data were available on the same fracture. It is found that reasonably accurate predictions of hydraulic conductivity can be made based solely on the first two moments of the aperture distribution function, and the proportion of contact area. 相似文献
134.
P. Pissis A. A. Konsta S. Ratkovič S. Todorovič J. Laudat 《Journal of Thermal Analysis and Calorimetry》1996,47(5):1463-1483
Broad-band ac dielectric relaxation spectroscopy (DRS) and various techniques of thermally stimulated currents (TSC) have been used to investigate molecular mobility in cereal and legume seeds, over wide ranges of water content and temperature. We focused our interest on the detailed study of the interactions between water and seed constituents. The results are quantitatively discussed, using various concepts dictated by the experimental techniques employed and in relation to the protein and carbohydrate contents of the seeds. In addition, the glass transition in the seeds, freezing and melting of water, and the protonic conduction process have been studied in some detail.Financial support through the Greek Ministry of Industry, Energy and Technology (Secretariat of Research and Technology), the Czech Ministry of Education, Youth and Sport (Dept. of International Scientific and Technological Cooperation), and the Empirikos Foundation is gratefully acknowledged. 相似文献
135.
白藜芦醇分子的转动惯量和电偶极矩 总被引:4,自引:0,他引:4
通过分子轨道理论和杂化轨道理论推断出较稳定的白藜芦醇分子是平面型分子,然后根据白藜芦醇分子结构特点计算了该化合物的一种稳定异构体的转动惯量,用矢量合成法计算了其电偶极矩,为微波辅助白藜芦醇萃取理论研究提供转动惯量和电偶极矩的数据. 相似文献
136.
Ionic mobility data for multicomponent electrolyte systems at low concentrations are scarce due to experimental difficulties and are actually restricted to aqueous solutions of alkali chlorides. Some new results are presented which have been obtained by using a radiotracer method valid even if one of the ionic species is present at very low concentrations (tracer ion). The following electrolyte systems (two electrolytes with a common ion in a solvent) have been investigated at a 0.5N total ionic strength: NaNO3–AgNO3, KNO3–AgNO3, LiNO3–AgNO3 either in pure water or in water-rich (acetonitrile or dimethylsulfoxide) mixed solvents. Since ionic conductivity data processing by an extended law generalized to mixtures, such as that proposed by Quint and Viallard, has proved to be delicate to handle, our experimental results have been compared with the qualitative predictions of the classical Onsager-Fuoss limiting law. The main conclusion of this work is to give clear experimental evidence of the inability of any continuum theory to predict the ionic mobilities when solvent structural effect have to be taken into account. Consequently, the ionic behavior, particularly that of the Ag+ ion, has been interpreted in terms of preferential solvation and solvent microscopic structure. The trace mobility measurements reflect the maximum structural effect on the ionic transport properties. 相似文献
137.
This work deals with uncertainty analysis of the thermal conductivity measurement using the transient hot wire method. The characterization is made from a sample of low-density, polyethylene BRALEN SA 200-22. The utilized experimental data are obtained from the test measurements performed on the air at room temperature. The sources of measurement errors are analyzed and the uncertainty of the measured value of the thermal conductivity is evaluated. The analysis shows that in the present case the uncertainty of the thermal conductivity measurement is about ±3.3% for 68% confidence level.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
138.
The heat transfer mechanisms in inorganic hollow micro-spheres filled polymer composites are analyzed in the present paper. This heat transfer includes mainly three mechanisms: (1) thermal conduction between solid and gas; (2) thermal radiation between the hollow micro-sphere surfaces; and (3) natural thermal convection of the gas in the micro-hollow spheres. A theoretical model of heat transfer in polymer/inorganic hollow micro-sphere composites is established based on the law of minimal thermal resistance and the equal law of the specific equivalent thermal conductivity, and a corresponding equation of effective thermal conductivity is derived. The effective thermal conductivity (keff) of hollow glass bead-filled polypropylene composites is estimated by using this equation, and is compared with the numerical simulations by means of a finite element method. The results show that the variation of the theoretical estimations of keff are similar to the numerical simulations at lower filler volume fraction (φf20%). Moreover, keff decreases linearly with increasing φf, and reduces somewhat with increase of filler size. 相似文献
139.
The relationship between the current and the bulk concentration of complex ions during concurrent specific adsorption of an electrochemically active complex ion and a complexing ligand is considered. The effect of parameters that characterize adsorption of such ions and the structure of the electrical double layer on this relationship is analyzed.__________Translated from Elektrokhimiya, Vol. 41, No. 7, 2005, pp. 817–822.Original Russian Text Copyright © 2005 by Rogozhnikov. 相似文献
140.