On the theory of acoustic solitons in a liquid with distributed gas bubbles

A close relation is established between numerical solutions to two systems of equations, viz., the two-level nonlinear wave dynamic model of a liquid with gas bubbles and the Korteweg-de Vries (KdV) equation. This model is used for deriving the KdV equation in the long-wave approximation for any dependent variable of the gas-liquid mixture. The KdV equations derived earlier using radically different approximations are particular cases of our equations.     

Steps Towards the Axiomatic Foundations of the Relativistic Quantum Field Theory: Spin-Statistics, Commutation Relations, and CPT Theorems

A realistic physical axiomatic approach of the relativistic quantum field theory is presented. Following the action principle of Schwinger, a covariant and general formulation is obtained. The correspondence principle is not invoked and the commutation relations are not postulated but deduced. The most important theorems such as spin-statistics, and CPT are proved. The theory is constructed form the notion of basic field and system of basic fields. In comparison with others formulations, in our realistic approach fields are regarded as real things with symmetry properties. Finally, the general structure is contrasted with other formulations.     

在伽利略坐标变换下的二端面弹性转轴相似动力学方程

在非相对论性原理下建立了二端面弹性转轴的相似动力学方程.使弹性转轴的动力学方程与地面坐标下的动力学方程相似,为相似工程学和计量、测控仪器的相似标定提供理论依据及方法 关键词： 二端面弹性转轴 相似模拟 坐标变换 相似动力学方程 标定     

Dynamic characteristics of curved nanobeams using nonlocal higher-order curved beam theory

Here, an analytical approach for the dynamic analysis, viz., free and forced vibrations, of curved nanobeams using nonlocal elasticity beam theory based on Eringen formulation coupled with a higher-order shear deformation accounting for through thickness stretching is investigated. The formulation is general in the sense that it can be deduced to analyse the effect of various structural theories pertaining to curved nanobeams. It also includes inplane, rotary and coupling inertia terms. The governing equations derived, using Hamiltons principle, are solved in conjunction with Naviers solutions. The free vibration results are obtained employing the standard eigenvalue analysis whereas the displacement/stress responses in time domain for the curved nanobeams subjected to rectangular pulse loading are evaluated based on Newmarks time integration scheme. The formulation is validated considering problems for which solutions are available. A comparative study is done here by different theories obtained through the formulation. The effects of various structural parameters such as thickness ratio, beam length, rise of the curved beam, loading pulse duration, and nonlocal scale parameter are brought out on the dynamic behaviours of curved nanobeams.     

Global plasma turbulence simulations of q = 3 sawtoothlike events in the RTP tokamak

A two-fluid computer model of electromagnetic tokamak turbulence, CUTIE, is used to study the dynamic structure and turbulent transport in the Rijnhuizen Tokamak Project tokamak. A discharge with dominant, off-axis electron cyclotron heating is the main focus of the simulations which were extended over several resistive diffusion times. CUTIE reproduces the turbulent transport and MHD phenomena of the experiment. The noninductive components of the current density profile, viz., the dynamo current and the bootstrap current, are identified as key players in the turbulent transport and its suppression and in off-axis MHD events.     

Quantum net dynamics

The quantum net unifies the basic principles of quantum theory and relativity in a quantum spacetime having no ultraviolet infinities, supporting the Dirac equation, and having the usual vacuum as a quantum condensation. A correspondence principle connects nets to Schwinger sources and further unifies the vertical structure of the theory, so that the functions of the many hierarchic levels of quantum field theory (predicate algebra, set theory, topology,..., quantum dynamics) are served by one in quantum net dynamics.     

Spin diffusion and relaxation in three-dimensional isotropic Heisenberg antiferromagnets

A theory is proposed for kinetic effects in isotropic Heisenberg antiferromagnets at temperatures above the Néel point. The scaling behavior of the generalized coefficient of spin diffusion and relaxation constant in the paramagnetic phase is studied in terms of the approximation of interacting modes. It is shown that the kinetic coefficients in an antiferromagnetic system are singular in the fluctuation region. The corresponding critical indices for diffusion and relaxation processes are calculated. The scaling dimensionality of the kinetic coefficients agrees with the predictions of dynamic similarity theory and a renormalization group analysis. The proposed theory can be used to study the momentum and frequency dependence of the kinetic parameters, and to determine the form of the scaling functions. The role of nonlocal correlations and spin-fluid effects in magnetic systems is discussed. Zh. éksp. Teor. Fiz. 112, 1816–1829 (November 1997)     

Vertex Algebras in Higher Dimensions and Globally Conformal Invariant Quantum Field Theory

We propose an extension of the definition of vertex algebras in arbitrary space–time dimensions together with their basic structure theory. A one–to–one correspondence between these vertex algebras and axiomatic quantum field theory (QFT) with global conformal invariance (GCI) is constructed.     

Some effects of tyre tread and road surface on road noise

A complex dynamic system can often be modeled in terms of coupled basic dynamic systems. A basic dynamic system is a system whose response can be specified in terms of a scalar quantity. A general formalism, dealing with the response of a complex dynamic system, is developed. The formalism spans several previous formalisms and encompasses new material that has not been previously considered, e.g., direct couplings between the ribs on a panel. The format is chosen so that it provides for consideration of elements of the statistical energy analysis (SEA). Thus, for example, the expression for the frequency spectral power flow between two basic dynamic systems is derived and cast in a modal form. In particular, various conditions and approximations under which cross modal terms vanish in the expression are specified and interpreted. Modal densities are defined and used to obtain further reductions in the expression for the power flow between two multimodal basic dynamic systems.     

The application of the theory of similarity to electron processes in p-n junctions

The authors consider in detail the methodology of applying the methods of similarity theory to electron processes in p-n junctions. They give the main similarity criteria and formulate the similarity conditions for the electron processes in semiconductor devices. They also cite examples of processing the experimental data in the criterial form.The authors thank Prof. V. A. Venikov and Candidate of Technical Sciences A. D. Shinkov for helpful discussions and valuable comments.     

Excitation and recombination processes during electroluminescence of rare earth-activated materials

Electroluminescence phenomena in rare earth doped materials are reviewed. The main emphasis is in the basic physics of EL processes, viz. direct and indirect excitation and nonradiative and radiative recombination of rare earth ions. The device structures, the recent material development, and the present state of art in AC operated thin fdm EL devices have been reviewed as well.     

点阵平面几何学

本文用欧几里得算法,给出求解基矢变换对应矩阵的解析表达式。分析了点阵平面及复合点阵平面的画法,并指出其应用范围。 关键词：     

Dynamic statistical information theory

In recent years we extended Shannon static statistical information theory to dynamic processes and established a Shannon dynamic statistical information theory, whose core is the evolution law of dynamic entropy and dynamic information. We also proposed a corresponding Boltzmman dynamic statistical information theory. Based on the fact that the state variable evolution equation of respective dynamic systems, i.e. Fokker-Planck equation and Liouville diffusion equation can be regarded as their information symbol evolution equation, we derived the nonlinear evolution equations of Shannon dynamic entropy density and dynamic information density and the nonlinear evolution equations of Boltzmann dynamic entropy density and dynamic information density, that describe respectively the evolution law of dynamic entropy and dynamic information. The evolution equations of these two kinds of dynamic entropies and dynamic informations show in unison that the time rate of change of dynamic entropy densities is caused by their drift, diffusion and production in state variable space inside the systems and coordinate space in the transmission processes; and that the time rate of change of dynamic information densities originates from their drift, diffusion and dissipation in state variable space inside the systems and coordinate space in the transmission processes. Entropy and information have been combined with the state and its law of motion of the systems. Furthermore we presented the formulas of two kinds of entropy production rates and information dissipation rates, the expressions of two kinds of drift information flows and diffusion information flows. We proved that two kinds of information dissipation rates (or the decrease rates of the total information) were equal to their corresponding entropy production rates (or the increase rates of the total entropy) in the same dynamic system. We obtained the formulas of two kinds of dynamic mutual informations and dynamic channel capacities reflecting the dynamic dissipation characteristics in the transmission processes, which change into their maximum—the present static mutual information and static channel capacity under the limit case where the proportion of channel length to information transmission rate approaches to zero. All these unified and rigorous theoretical formulas and results are derived from the evolution equations of dynamic information and dynamic entropy without adding any extra assumption. In this review, we give an overview on the above main ideas, methods and results, and discuss the similarity and difference between two kinds of dynamic statistical information theories.     

Map-based model of the cardiac action potential

A simple computationally efficient model which is capable of replicating the basic features of cardiac cell action potential is proposed. The model is a four-dimensional map and demonstrates good correspondence with real cardiac cells. Various regimes of cardiac activity, which can be reproduced by the proposed model, are shown. Bifurcation mechanisms of these regimes transitions are explained using phase space analysis. The dynamics of 1D and 2D lattices of coupled maps which model the behavior of electrically connected cells is discussed in the context of synchronization theory.     

Collisional and radiative processes with participation of highly excited states of atoms and molecules

A number of processes in which highly excited states of atoms and molecules participate are investigated. These processes are of interest for the kinetics of a low-temperature plasma, for atomic and molecular spectroscopy, and for astrophysics. A quasiclassical theory is developed for transitions between Rydberg states with change of the principal quantum number, and also for the processes of direct and associative ionization of highly excited atoms, which result from collisions between a neutral particle and its atomic core. The state of the inner electrons of a quasimolecular (molecular) ion is not altered by transitions of the outer electrons. Specific calculations are carried out for the case of the collision of hydrogen H(n) with helium He (1s²) atoms. It is shown that the cross sections and the rate constants of these processes are determined in this case by the mechanism investigated in the paper, and not by scattering of the Rydberg electron by the neutral particle. The cross sections for dipole excitation and dissociation of molecular ions from high vibrational energy levels by electron impact is calculated in the Born-Coulomb approximation. The cross sections and the rates of dissociative and three-particle attachment of electrons to ions are determined. The processes of autoionization and autodissociation decay of Rydberg states of vibrationally excited molecules are determined. Also investigated are radiative transitions near the dissociation limit of diatomic molecular ions and neutral molecules, viz., photodissociation and radiative decay of high vibrational levels, and photodissociation and translational (inverse-bremsstrahlung) absorption in collision of atomic particles.Translated from Trudy Ordena Lenina Fizicheskogo Instituta im. P. Lebedeva AN SSSR, Vol. 145, pp. 80–130, 1984.     

二维形变谐振子系统中的量子经典对应

通过引入等效普朗克常数,将量子系统中基本动力学变量的期望值和经典系统中基本动力学变量的精确值的时间演化行为相比较,分析了两者产生差异的因素,规则运动主要是和量子效应有关,而混沌运动则是和动力学效应有关,即与系统的动力学对称性破坏相联系.在此基础上,比较了量子相空间测不准度和李雅谱诺夫指数,给出了令人满意的说明.     

Microstructure of the supersaturation field in homogeneous nucleation in a vapor-gas mixture

An explanation of a significant difference between the modern experimental data on nucleation rate and the results of the classical theory of nucleation is proposed on the basis of analysis of the mass transfer during the growth of dropletlets from clusters. The continuous operation devices, viz., a laminar diffusion chamber and a diffusion chamber, are considered.     

Stochastic resonance as dithering

A direct correspondence is demonstrated between the phenomenon of "stochastic resonance" in static nonlinear systems and the dithering effect well known in the theory of digital waveform coding. It is argued that many static systems displaying stochastic resonance are forms of dithered quantizers, and that the existence or absence of stochastic resonance in such systems can be predicted from the effects of "dither averaging" upon their transfer characteristics. Also, results are introduced regarding stochastic resonance in certain nonlinear systems with memory (e.g., hysteretic systems).     

Some consequences of the Finslerian structure of the space-time with the absolute parallelism

In the present paper the correspondence between the Reimannian and the Finslerian metric structures of the space-time with the absolute parallelism is considered. The statistical characteristics of the gravitational field, defined by the Finslerian metrization, are investigated. Some basic principles of the development of the theory of physical fields, depending on the line support elements, are discussed.     

Effects of nonlinear amplification in quantum-dimensional lasers based on asymmetric heterostructures

We investigated the possibility of describing the processes of radiation generation at two spectrally spaced wavelengths in quantum-dimensional lasers based on asymmetric heterostructures by means of rate equations that take account of the effects of nonlinear amplification. We show that agreement between experimental and theoretical results is achieved in the case where it is assumed that the processes of interaction between spectrally spaced modes prevail over the processes of self-stress of the modes. An analysis of various mechanisms of nonlinear amplification is carried out, and it is found that dynamic heating of charge carriers by radiation is a reason for nonlinear phenomena with the features indicated. To whom correspondence should be addressed. Reported at the Second International Scientific and Technical Conference on Quantum Electronics, Minsk, November 23–25, 1998. Belarusian State University, 4, F. Skorina Ave., Minsk, 220050, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 5, pp. 697–702, September–October, 1999.