Influence of Adsorption and Desorption of Gas Micronuclei on the Nature of the Flow of a Gassy Liquid through a Porous Medium

The problem of gassy liquid flow through a porous medium is considered theoretically. Periodic oscillations of the liquid and gas flow rate observed experimentally are attributable to the processes of sorption and desorption of gas micronuclei on the walls of the pore space and their diffusion. In the kinetic equation employed the desorption rate is directly proportional to the adsorbed micronucleus concentration and the seepage rate, and the adsorption rate is directly proportional to the product of the mobile micronucleus concentration and the free site concentration on the pore surfaces. Steady-state solutions of this equation are investigated. It is shown that periodic oscillations of the flow rate can manifest themselves only when the processes of micronuclei adsorption predominate over the desorption processes.     

Quantum Macroscopic Effects in a Degenerate Strongly Magnetized Nucleon Gas

A model of a degenerate gas consisting of neutrons that are in chemical equilibrium with degenerate protons and electrons in a stationary and homogeneous superstrong magnetic field is used to describe the state of the matter in central regions of strongly magnetized neutron stars. Expressions for thermodynamic quantities (such as energy density, particle density, pressure, and magnetization) characterizing a degenerate gas of neutrons, protons, and electrons are obtained. In these expressions, the contributions determined by the interaction between anomalous magnetic moments of fermions and the magnetic field are taken into account. Macroscopic effects that may occur in strongly magnetized neutron stars are discussed. We show that all thermodynamic quantities characterizing electrically charged fermions in a strong magnetic field are subject to nonperiodic oscillations caused by the interaction of the anomalous magnetic moments of protons and electrons with the magnetic field. We also show that if the nucleon density and the electron density exceed threshold values that are relatively small and depend on the magnetic field strength, all fermions are fully polarized with respect to the spin. The full spin polarization effect in neutrons is caused by the interaction between the anomalous magnetic moment and the magnetic field. The obtained results may prove useful in understanding processes that occur in the nucleus of a neutron star with a magnetic field frozen into the star.     

Dynamic behavior of Ni-H<Subscript>2</Subscript>SO<Subscript>4</Subscript> system at high anodic potentials and different electrolysis conditions

The stability and dynamic properties of the Ni-H₂SO₄ system is studied at high anodic potentials and different electrolysis modes. The systems dynamic behavior is shown to depend on the electrode reaction mechanism and the electrolysis mode that ensures consistent progress of all stages of the overall process.Translated from Elektrokhimiya, Vol. 41, No. 1, 2005, pp. 111–115.Original Russian Text Copyright © 2005 by Kovtun, Bolotin.     

Critical fluctuation universality in chemically oscillatory systems: A soluble master equation

Multiple time scale arguments are used to show that near a Hopf bifurcation to a chemical oscillation the dynamics of the system reduces to that of a classic soluble limit cycle system. A birth and death master equation is then introduced and the spectrum of the resulting transition operator is shown to be complex. Exact solutions of the master equation are obtained both for the steady and (for a rather general class of systems) excited states. Thus a simple basis of universality of critical properties in chemical oscillations is provided.Research supported in part by a grant from the National Science Foundation.     

Current oscillations during copper electrodissolution under solution sparging in acidic NaCl solutions

Potentiostatic current oscillations were observed during electrodissolution of a helical coiled copper wire electrode in acidic sodium chloride when nitrogen was sparged through the solution. The oscillations were studied as a function of solution pH, chloride ion concentration and sparging rate over the potential range of 0.2 to 0.7 V versus Ag/AgCl (3 M NaCl). The surface morphology of the copper was observed during the oscillatory process using in situ, real-time optical microscopy, and the formation of a surface film was correlated with the oscillations.     

Off-diagonal long-range order, η-pairing,and Friedel oscillations in high Tc cuprate superconductors and the ground state of the extended Hubbard model

It is argued that Yang's η-paired wave function is the electronic ground state of high T_c cuprate superconductors. © 1997 John Wiley & Sons, Inc. Int J Quant Chem 63: 675–684, 1997     

块体TaP 极大磁阻及量子振荡特性研究

Weyl 半金属因其载流子满足外尔运动方程, 表现出高迁移率、 极大磁阻等新奇量子物性, 从而在无耗散电子器件应用中具有广泛应用前景. 在本文中, 我们系统研究了块体 TaP 样品的磁电输运特性, 获得了高达106 %极大的磁阻特性和显著的SdH 振荡特性. 结合TaP 样品载流子随温度的变化行为, 我们进一步揭示了块体TaP 样品的极大磁阻的物理起源, 在低温下, 其主要来源于样品费米面附近近似补偿的空穴和电子, 而在高温下则主要来源自块体TaP 样品中增强的电子散射作用. 我们的实验结果为理解 Weyl 半金属新奇量子输运特性和器件设计开发提供了实验参考.     

硫酸溶液中重铬酸钾在金电极上还原过程中的两种电势振荡

Two different types of potential oscillations have been identified for the first time during dichromate reduction on a gold electrode in a solution of dilute sulfuric acid. One occurs before hydrogen evolution due to the formation and dissolution of passivating films of low-valence chromium oxides, and the other generates,accompanying periodic hydrogen evolution, from the coupling of electrochemical reactions with diffusive and convective mass transport. More interestingly, these two types of oscillations correspond to two crossing loops in the cyclic voltammogram (CV). Such a relation of oscillations with crossed CVs will provide a new way to find electrochemical oscillatory systems systematically and rapidly.     

Generalization of the method of full approximation and its applications

This paper presents a generalized form of the method of full approximation.By usingthe concept of asymptotic linearization and making the coordinate transformationsincluding the nonlinear functionals of dependent variables,the original nonlinear problemsare linearized and their higher-order solutions are given in terms of the first-termasymptotic solutions and corresponding transformations.The analysis of a model equationand some problems of weakly nonlinear oscillations and waves with the generalized methodshows that it is effective and straightforward.     

Collective modes and the far-infrared absorption of the two-dimensional electron gas in a periodic quantizing magnetic field

We investigate the far-infrared (FIR) absorption of a two-dimensional electron gas in a periodically modulated quantizing magnetic field. The magnetic field varies along only one spatial direction and the external time-dependent electric field is linearly polarized along that axis. The mutual Coulomb interaction of the electrons is treated self-consistently in the ground state and in the absorption calculation within the Hartree approximation. The effects of the magnetic material on top of the heterostructure as a grating coupler is included in the time-dependent incident FIR electric field. We show that, similar to an electric modulation, the absorption can be directly correlated to the underlying electronic energy bands. In addition, the magnetic modulation leads to absorption spectra with a richer structure due to the quite different static response of the electron density to the modulation.