Derivation of a hydrodynamic equation for Ginzburg-Landau models in an external field

The lattice approximation to a time-dependent Ginzburg-Landau equation is investigated in the presence of a small external field. The evolution law conserves the spin, but is not reversible. A nonlinear diffusion equation of divergence type is obtained in the hydrodynamic limit. The proof extends to certain stochastically perturbed Hamiltonian systems.     

On determining the profile of steady wind-induced currents

A technique is developed to solve the steady-state hydrodynamic equations which describe wind-induced currents at a point. By using the Galerkin approach, with an expansion of complex coefficients and real functions, a continuous current profile can be computed from sea surface to sea bed for arbitrary vertical variations of viscosity. The method can incorporate slip or no-slip bottom boundary conditions, and gradients of sea surface elevation. The technique is used to investigate the influence of viscosity profile, bed stress and elevation gradient on surface current magnitude and direction. Calculations suggest that viscosity profile, bed stress, and elevation gradient all affect surface current, offering some explanation for the range of surface current magnitudes and directions reported in the literature.     

Fluctuations in a one-dimensional mechanical system. I. The Euler limit

We prove the central limit theorem for the density fluctuation field of a one-dimensional mechanical system (hard rods with equal masses and lengths and elastic collisions) in the hydrodynamic limit on the Euler time scale. The limiting process is deterministic and is governed by the linearized Euler equations of the model.     

Depolarized light scattering from liquids: Rotations,collisions, and hydrodynamics

VH depolarized light scattering from liquids composed of symmetric top molecules is discussed. The dielectric fluctuations which give rise to the spectrum form an orientational and collisional (or intermolecular) contribution, and cross-correlation between the two can occur. The problem of disentangling the orientational from the collisional effects is shown to be possible, at least within the context of a generalized hydrodynamic model, because of the coupling of rotations and intermolecular interactions to hydrodynamic shear modes. A simple generalized hydrodynamic model is proposed which is successful in describing the observed spctra with an appropriate number of theoretical transport coefficients treated as adjustable parameters. Though this model is quite successful, and though the coefficients can all be described in physically meaningful and mathematically precise molecular terms, it must still be taken as a phenomenological theory until the fitted values of the coefficients can be compared with values calculated from the molecular expressions.     

Rational Profiling of Equal-Stress-Reinforced Plates Subjected to Elastoplastic Transverse Bending

The problem of rational profiling of equal-stress-reinforced Kirchhoff plates subjected to purely elastic and elastoplastic transverse bending is formulated. A qualitative analysis of the systems of resolving equations is carried out. It is found that the problem can have two possible solutions, which can be controlled. By particular calculations, it is shown that, through rational profiling of the bent plates, the consumption of phase materials in them can be reduced greatly compared with that in traditional ones, or the load-carrying capacity of the plates can be raised significantly at a fixed consumption of phase materials.     

The stability of the boundary layer on a compliant rotating disc

The boundary layer over a infinite rotating disc is 3D and offinite depth. The breakdown and eventual transition of flowover the surface is preceded by the emergence of crossflow vorticesthat are stationary with respect to the disc. These result froman inviscid instability mechanism associated with an inflexionpoint within the boundary layer's velocity profile or a mechanisminduced by the balance between viscous and Coriolis forces.It has been seen in past studies that compliance can substantiallypostpone the onset of transition, therefore the aim of thisresearch is to investigate whether compliance can be used asa useful tool to do so here. We use numerical and asymptoticmethods to predict possible behaviour by calculating growthrates and producing neutral solutions for the wave number andorientation of both inviscid and viscous modes. The resultsobtained suggest that the inviscid mode of instability willbe stabilized by compliance but the viscous mode will be greatlydestabilized.     

Hydrodynamic limits for the Boltzmann process

We study the behavior of the nonlinear Markov process associated to the Boltzmann equation under both hyperbolic and parabolic space-time scalings. In the first case the limit of the process is the solution of an o.d.e. with vector field given by a solution of the Euler equation, while in the second case the limit of the process, in the incompressible case, turns out to be a diffusion process whose drift is a solution of the incompressible Navier-Stokes equation.     

长脂链巴比妥酸和四氨基嘧啶的分子组装体的研究

长脂链巴比妥酸和四氨基嘧啶的分子组装体的研究王志强，王力彦，张希，沈家骢（吉林大学分子光谱与分子结构开放实验室，长春，１３００２３）关键词分子识别，分子组装体，长脂链巴比妥酸，四氨基嘧啶靠氢键、静电、疏水等弱相互作用及其协同作用，在气／液、液／液及液...