范氏气体的准静态绝热方程

应用两种不同方法导出范氏气体的准静态绝热方程，解决了相关文献未能解决的问题．     

光电液位传感测量系统的准静态特性研究

光电液位传感位移测量系统中,液体作为测量的特殊敏感元件,其准静态特性研究的滞后一直制约着系统进行准静态测量的应用。为此,建立了三通道连通管模型,推导了液位振荡的运动方程。通过分析知连通管的直径、液体总长以及液体的运动粘滞系数是影响液体准静态特性的主要因素。在此基础上进行了准静态特性实验。实验结果验证了液位振荡规律,得到了各系统参数对液位振荡的影响特性,从而得到系统的优化准则。     

On the theory of optical properties of fractal clusters

A theory of optical properties of clusters of spherical metal nanoparticles characterized by an arbitrary size distribution is developed in a quasi-static dipole approximation. The equations for coupled dipoles and general relations are formulated in terms of reduced dipole moments. It is shown that the dipole resonant frequencies and amplitudes, the absorbed power, and the acting-field magnitudes strongly depend on the ratios of particle radii in a cluster. Properties of linear, planar, and three-dimensional systems are examined.     

An evolution of adiabatic matter: a case for the quasistatic regime

We establish the connection between the standard ADM 3+1 treatment of matter with its characteristic equivalent, in the context of spherical symmetry. The flux-conservative rendition of the fluid equations are obtained. Considering adiabatic distributions of perfect fluid, we evolve the system using the so-called post-quasi-static approximation in radiation coordinates. We obtain an adiabatic matter evolution in the quasi-static regime or slow motion, which is not shear-free nor geodesic.     

Quasi-static analysis of multicrossover structures in grounded two-layer dielectric media

The capacitive coupling effects of multi-crossover structures in grounded two-layer dielectric media are investigated by a set of generalized quasi-static formulations. The moment method is employed to solve the set of generalized integral equations for the charge densities. Both the distributed capacitances and the lumped excess capacitances are computed.     

Three-dimensional constitutive equations for Ni–Mn–Ga single crystals

This paper presents a formulation of isothermal three-dimensional (3D) quasi-static magneto-mechanical constitutive equations and 3D magnetisation constitutive equations for tetragonal martensite Ni–Mn–Ga FSMA single crystals (c/a<1)$(c/a<1)$ with both ends restrained from twin-boundary motion. The formulated 3D constitutive equations model the 3D quasi-static magnetic fields as well as the coupling between uniaxial strains and stresses, and shear strains and stresses. The constitutive equations are compared with experimental results available in the literature and are found to correlate well with the experimental results, including magnetic field reversals. Both sets of 3D constitutive equations require only macroscopic parameters that are readily obtainable from magnetisation and mechanical stress–strain curves.     

Relaxation of the Probability Characteristics of Brownian Motion under the Action of a Dichotomous Random Force

We consider the relaxation of rms characteristics of the coordinates of particles during their Brownian motion in a symmetric potential profile under the action of a dichotomous random force. An analytical-numerical method of analysis based on the numerical solution of a chain of differential equations for coordinate moments and joint correlations is used. The calculation procedure is checked using exact results which can be found in the limiting cases of delta-correlated and quasi-static random action. The dependence of the distribution variance and its relaxation time on the intensity and correlation time of noise is elucidated.     

Phase-space moment-equation model of highly relativistic electron-beams in plasma-wakefield accelerators

We formulate a new procedure for modelling the transverse dynamics of relativistic electron beams with significant energy spread when injected into plasma-based accelerators operated in the blow-out regime. Quantities of physical interest, such as the emittance, are furnished directly from solution of phase space moment equations formed from the relativistic Vlasov equation. The moment equations are closed by an Ansatz, and solved analytically for prescribed wakefields. The accuracy of the analytic formulas is established by benchmarking against the results of a semi-analytic/numerical procedure which is described within the scope of this work, and results from a simulation with the 3D quasi-static PIC code HiPACE.     

A derivation of the Christoffel equation with damping

This paper provides a derivation of the Christoffel eigenvalue equation for acoustic wave propagation in an acoustically damped piezoelectric medium. The damping tensor is shown to couple into both the stress and displacement constitutive equations. Application of the quasi-static approximation leads to an additional term in the Christoffel equation that generates a complex k-vector, due both to introduction of a complex term and to breaking of symmetry in the left-hand side of the eigenvalue equation, subsequently resulting in damping and a phase shift for a plane wave solution. Shown are the effects of damping on the eigenvalues of the piezoelectrically stiffened Christoffel equation for plane wave propagation in unconstrained quartz over a 1 MHz to 1 GHz frequency range.     

The forced motion of viscoelastic thick cylindrical shells

This paper presents a theoretical analysis of a dynamic boundary value problem of the axially-symmetric motion of isotropic, homogeneous, linearly-viscoelastic, thick, cylindrical shells subjected to time-dependent surface tractions and/or time-dependent boundary conditions. Williams' modal-acceleration method has been used to treat the time-dependent boundary conditions. Two forms of the correspondence principle are used to obtain the governing differential equations and the quasi-static solutions. A numerical example is given to study the transient response of a cylindrically hollow rod subject to longitudinal impacts.     

Dynamical Evolution and Leading Order Gravitational Wave Emission of Riemann-S Binaries

An approximate strategy for studying the evolution of binary systems of extended objects is introduced. The stars are assumed to be polytropic ellipsoids. The surfaces of constant density maintain their ellipsoidal shape during the time evolution. The equations of hydrodynamics then reduce to a system of ordinary differential equations for the internal velocities, the principal axes of the stars and the orbital parameters. The equations of motion are given within Lagrangian and Hamiltonian formalism. The special case when both stars are axially symmetric fluid configurations is considered. Leading order gravitational radiation reaction is incorporated, where the quasi-static approximation is applied to the internal degrees of freedom of the stars. The influence of the stellar parameters, in particular the influence of the polytropic index n, on the leading order gravitational waveforms is studied.     

C型固体电枢3维有限元电磁发射计算

对轨道型固体电枢电磁发射的电磁过程进行了研究,建立了基于麦克斯韦准静态A-Φ场方程的3维静枢电磁发射数值模型。利用ANSYS有限元电磁模块结合发射装置的实测参数,对电枢在静枢模型下的电磁发射进行了模拟。计算结果表明:馈入相同电流加载波形时,流经C型电枢的电流密度、磁通量以及电磁发射过程中所受电磁力,在不同时刻的内部分布、峰值和大小均与文献计算结果相符。     

Generalizations of SRB Measures to Nonautonomous,Random, and Infinite Dimensional Systems

We review some developments that are direct outgrowths of, or closely related to, the idea of SRB measures as introduced by Sinai, Ruelle and Bowen in the 1970s. These new directions of research include the emergence of strange attractors in periodically forced dynamical systems, random attractors in systems defined by stochastic differential equations, SRB measures for infinite dimensional systems including those defined by large classes of dissipative PDEs, quasi-static distributions for slowly varying time-dependent systems, and surviving distributions in leaky dynamical systems.     

厚金属靶在弹丸打击下的侵彻与穿透

 给出了预测厚金属靶在不同形状弹头弹丸大速度范围内打击下侵彻与穿透的简单分析方程。在方程的建立过程中，假定变形是局部化的、冲击能量仅由侵彻过程吸收，并进一步假定靶材料对弹丸的平均阻（压）力由两部分组成：一部分基于空穴膨胀理论由于靶材料弹-塑性变形所产生的准静态凝聚阻力；另一部分是考虑了速度效应后的动压力。推导出了预测靶侵彻深度和弹道极限的方程表达式，并与金属靶在不同形状弹头弹丸大速度范围内打击下侵彻与穿透的实验进行了比较。理论预测与实验结果吻合得很好。     

Dispersion relation for space-charge waves in a warm plasma-filled elliptical waveguide in an infinite axial magnetic field

A perfectly conducting elliptical cylinder filled with a warm plasma and immersed in an infinite axial magnetic field is considered. Using Maxwell’s equations and dielectric tensor, a Mathieu differential equation for axial component of electric field is obtained. Considering the boundary conditions, dispersion relation for waves in a plasma of warm electrons and immobile ions, which fills an elliptical waveguide and it is under the action of infinite axial magnetic field are calculated. Furthermore, dispersion relation and scalar potential in the quasi-static approximation in a cold magnetized plasma elliptical waveguide is calculated. The obtained results are graphically presented.     

Generation of point defects in alloys with theL12 superlattice

The generation of point defects by screw superdislocations in the act of forming a shear zone in single crystals of alloys with the L1₂ superlattice is examined. The fraction of mobile jogs occurring in superpartial dislocations is estimated. A balance equation for point-defect concentrations in this kind of alloy under quasi-static deformation is derived. A mathematical model for work-hardening of these alloys, involving balance equations for dislocations and point defects, is constructed. Tomsk State University of Architecture and Building. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 66–70, January, 2000.     

Particles production in expanding color flux tube

This article generalizes Schwinger’s mechanism for particle production in the time dependent field volume in the quasi-static approximation. Solution of DGLAP equations in the double leading log approximation for a small x gluon distribution function was used to derive the new formula for initial chromofield energy density. This initial chromofield energy is distributed among color neutral clusters or strings. These strings are stretched by the receding nucleus. From the proposed mechanism of string fragmentation or color field decay, the new formula for the rapidity spectrum of produced partons was derived. The text was submitted by the author in English.     

Modelling of Binder-Induced Agglomeration

From the analysis of pendular liquid bridge forces between spherical particles, a model has been developed to predict bridge rupture energies. Whilst this model has been shown to predict the correct trends in certain stages of agglomeration, it is limited by the assumptions of zero contact angle, toroidal bridge geometry, spherical particles and quasi-static rupture. The work described here is aimed at extending the model to more generally applicable conditions using direct measurement of bridge rupture energies between particles down to 3 μm in diameter under different physiochemical conditions. Initial results show that the spreading coefficient of the binder to the particle has a marked effect on the dynamic behaviour of the bridge itself and its subsequent geometry at equilibrium, i.e. for non-zero contact angles theoretical equations tend to over-predict the force of adhesion, whilst for zero contact angles the force of adhesion agrees with that predicted using the Laplace equations for constant curvature. On the other hand, the corrected expression for maximum separation distance shows good agreement with experimental results.     

锥头弹丸撞击下固支金属厚靶的侵彻与穿透的理论研究(英文)

研究了在不同速度的刚性锥头弹丸撞击下固支金属厚靶的侵彻和穿透性能。假定靶板的变形是局部化的,且冲击能量仅通过侵彻过程吸收,同时假定弹体在侵彻过程中表面所受靶体的平均压力是由基于空穴膨胀理论的靶体材料弹塑性变形所引起的静态阻力以及速度效应引起的动阻力两部分组成,认为侵彻过程中靶体对弹体的静阻力要进行自由表面效应修正,而且动阻力是瞬时侵彻速度的函数。获得了锥头弹丸在侵彻和贯穿过程中的弹道极限速度和残余速度的公式。将理论预测与实验结果进行比较,发现两者符合得很好。     

对气体等温气压公式的修正

用理想气体的多方过程方程取代等温过程方程，推导出气体处于多方平衡过程时的气压公式，该公式是对气体等温气压公式的一种很好的修正．对多方指数”等于1，1．1，1．2，1．3，1．4等5种不同情况分别给出了大气压强随高度的变化曲线．此外还讨论了考虑到重力加速度随离地面高度的变化后对气压公式的修正．