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981.
光照法研究超氧化物歧化酶及其模型化合物与超氧离子的反应动力学 总被引:8,自引:0,他引:8
用改进的光照法研究了超氧化物歧化酶及其模型化合物μ-桥基·二(2,6-二乙酰基吡啶)缩二丙二胺合铜(Ⅱ)(桥基为SCN-,N3-,I-,Br-,Cl-,OH-)与超氧离子的反应动力学,测定了反应速率常数kQ,结果表明,超氧化物歧化酶的kQ与脉冲辐解法及黄嘌呤氧化酶法的结果一致。6种配合物中,Cu2L(SCN)(ClO4)3的kQ最大,Cu2L(N3)(ClO4)3的最小,并讨论了真kQ不同的原因。 相似文献
982.
The aim of this work is to study the transport mechanism of ions through nanofiltration membranes. A model based on extended Nernst–Planck and film theory equations is reported. This model can be characterized by three transport parameters: the water permeability Lp, the salt transmittance Φ and the effective salt transfer coefficient Keff. The knowledge of the feed and permeate concentration and of the permeate volumetric flux enable us to calculate these transport parameters. The model is used to estimate cadmium salts rejection by a NANOMAX 50 membrane. Experimental and calculated results are shown to be in good agreement. The model is then successfully extended to experimental data reported in the literature. 相似文献
983.
A. Ammar E. Pruliere F. Chinesta M. Laso 《ournal of non Newtonian Fluid Mechanics》2009,160(2-3):140-156
Kinetic theory models involving the Fokker–Planck equation can be accurately discretized using a mesh support (Finite Elements, Finite Differences, Finite Volumes, Spectral Techniques, …). However, these techniques involve a high number of approximation functions. In the finite element framework, widely used in complex flow simulations, each approximation function has only local support and is related to a node that defines the associated degree of freedom. In the technique proposed here, a reduced approximation basis is constructed. The new shape functions have extended support and are defined in the whole domain in an appropriate manner (the most characteristic functions related to the model solution). Thus, the number of degrees of freedom involved in the solution of the Fokker–Planck equation is very significantly reduced. The construction of those new approximation functions is done with an ‘a priori’ approach, which combines a basis reduction (using the Karhunen–Loève decomposition) with a basis enrichment based on the use of some Krylov subspaces. This paper analyzes the application of model reduction to the simulation of non-linear kinetic theory models involving complex behaviors, such as those coming from stability analysis, complex geometries and coupled models. We apply our model reduction approach to the Doi's classical constitutive equation for viscoelasticity of liquid-crystalline polymer. 相似文献
984.
A numerical model for free-surface flow of a viscoplastic liquid into a cavity is presented. This flow is regarded as a basic model of injection molding, which is a widely used processing technology. Model experiments of the injection process are performed with a water-based gel with shear-thinning behavior. The filling process is visualized by tracing the free surface of the gel within the cavity. Filling times of the cavity are deduced from the experimental observations. The filling process is also analyzed by means of numerical simulation.The flow equations are integrated according to the finite-volume method. The volume-of-fluid method is employed in order to describe the flow of two incompressible, immiscible phases, the phase interface is resolved by the method of geometric reconstruction or alternatively by the method of surface compression. The Herschel–Bulkley model is used in order to describe the shear-thinning behavior of the gel and the effects of a yielding point. The governing equations of the flow are solved by means of the commercial code Fluent as well as the Open Source code OpenFOAM.The results of the numerical simulations are analyzed in detail. They are compared with the experimental findings. Cavity filling times in the experiments and the simulations are in good agreement. Different patterns of the filling flow depending on the injection parameters are evident in the experiments and the simulations. They are characterized and arranged with respect to the similarity parameters of the flow configuration. Again, the results of the simulation are found to agree well with the experimental observations. 相似文献
985.
986.
We show that the spin-orbit potential of the nuclear mean field destroys isoscalar superfluid correlations in self-conjugate
nuclei. Using group theory and boson mapping techniques on a Hamiltonian including single particle splittings and a SO
ST(8) pairing interaction, we give analytical expressions for the spin-orbit dependence of some N = Z properties such as the relative position of T = 0 and T = 1 states in odd-odd systems or double binding-energy differences of even-even nuclei.
Received: 12 April 2000 / Accepted: 25 May 2000 相似文献
987.
1 hoeductIOuThe dynamics models of one--dimensional continuous medium nuclear reactor are the foelowing initial--boundary value problem of the formsubject to the innal conditionsand the boundary conditionsIn (1. 1), x denotes position along the reactor, which is regarded as a rod of length L, t denotes the time, u(t) the logarithm of the loud reactor POwer, v(x,t) the deviation of the temperature from equilibrium, a(x) the ratio of the temperature coefficient of reactivity to theynean life of… 相似文献
988.
This paper proposed new ways for producing multi-layer model grids for electron beam moiré method. An electron beam lithography system was set up under scanning electron microscope which was equipped with a beam blanking device and a pattern generator. The two-deposited-metal layers method was used to manufacture electron beam grating for high-temperature use. The results verify that the Zr–Pt-type grating possesses heat resistance up to 1100°C in vacuum. A new type of composite grating with frequencies 100 lines/mm and 1000 lines/mm using three deposited layers was produced. A 10 000 lines/mm two-deposited-metal layers grating was successfully fabricated using electron beam lithography. 相似文献
989.
In this paper, the single and two deposited metal layers method were proposed to produce the model grating for electron moiré method. The measurement principle of electron moiré method and the techniques for manufacturing model grid are expounded in detail. The accuracy of measuring strain using this method is discussed. The gratings with single deposited layer and two deposited layers with high frequency up to 5000 lines/mm were produced on different substrates. From the experimental results, both single deposited metal layer and two deposited metal layers gratings showed their heat resistance ability. Using the gratings produced and a replicated model grid, the electron moiré method was applied to measure the deformation of the strain around holes in a polyimide resin substrate, thermal strain of electronic packaging component and tensile creep around grain boundary in a pure copper specimen. 相似文献
990.
钙矾石3CaO·Al2O3·3CaSO4·32H2O是水泥熟料水化的重要产物.它易被空气中的CO2 分解,常温下的分解反应为3CaO·Al2O3·3CaSO4·32H2O 3CO2 →3CaCO3 Al2O3·xH2O 3(CaSO4·2H2O) (26 -x)H2O分解机理[1 ,2]是:H2O先吸附在钙矾石表面的活性中心上,吸附态水再吸收CO2 成为H2CO3 ,然后碳酸与钙矾石反应,实现碳化(即分解).其分解速率[3]为v=kpco2 pH2o(1)可见水的吸附是钙矾石碳化分解的关键步骤,因此探讨… 相似文献