热孤子与微细通道相变传热研究

针对微槽流动相变传热,在给出气泡平衡半径及初值条件的前提下,提出了气泡在微槽中演化半径的系综公式,结合气泡生长随机变量的相关性得出了气泡在微槽中生长所满足的随机微分动力方程,由方程的定态解进一步得出了微槽中气泡生长系统的势能及概率密度函数随半径的演化规律.根据微槽中反应气泡热通量的热孤子表达式,从理论上获得了以核态沸腾为主的微槽相变传热计算公式,并对具有23条平行的0.3mm×2mm微槽进行了相变传热实验.理论计算值与实验结果较吻合,误差小于7%,验证了该公式的可行性.

Stabilization of the Soliton Transported Bio-energy in Protein Molecules in the Improved Model

We study the stabilization of the soliton transported bio-energy by the dynamic equations in the improved Davydov theory from four aspects containing the feature of free motion and states of the soliton at the long-time motion and at biological temperature 300 K and behaviors of collision of the solitons by Runge–Kutta method and physical parameter values appropriate to the α-helix protein molecules. We prove that the new solitons can move without dispersion at a constant speed retaining its shape and energy in free and long-time motions and can go through each other without scattering. If considering further influence of the temperature effect of heat bath on the soliton, it is still thermally stable at biological temperature 300 K and in a time as long as 300 ps and amino acid spacings as large as 400, which shows that the lifetime of the new soliton is at least 300 ps, which is consistent with analytic result obtained by quantum perturbation theory. These results exhibit that the new soliton is a possible carrier of bio-energy transport and the improved model is possibly a candidate for the mechanism of this transport.

Influences of Temperature and Solvent Ions in Solution on States and Properties of Deoxyribonucleic Acid （DNA）

We here study the influences of the temperature and solvent ions in solution on the states and properties of DNA by a new dynamical model. This model admits three degrees of freedom per base-pair: two displacement variables related to the vibrations of the hydrogen atom in the hydrogen bonds and base (nucleotide), respectively, and an angular variable related to the rotation of each base, which delineate different forms of motion of the hydrogen atom and bases and the relations among them. In this -model we stress specially the important role of the hydrogen atom in the hydrogen bonds of the bases in the dynamics of DNA. According to their properties of motion we give the Hamiltonian of the system and the corresponding equations of motion, and End out their soliton solutions. The solitons formed by the displacements of the hydrogen atoms and bases and their rotations are the excitation states arising from the energy absorbed by the DNA working at the biological temperature. We give further the free energy of the thermal excitation state in DNA system by transfer integral way and End out the corresponding specific heat. The specific heat increases with the increasing of the temperature and concentration of the solvent ions in the solution, but is not linear changes in the region of high temperature. If compared with experimental data, they are approximately consistent. Meanwhile we End that the solvent ion conceptration influences seriously on the stability, states, and configurations of DNA.

（2＋1）-Dimensional Electron Acoustic Solitary Waves in an Unmagnetized Collisionless Plasma with Vortex-Like Hot Electrons

In this paper, （2＋1）-dimensional electron acoustic waves （EAW） in an unmagnetized collisionless plasma have been studied by the linearized method and the reductive perturbation technique, respectively. The dispersion relation and a modified Kadomtsev-Petviashvili （KP） equation have been obtained for the EAW in the plasma considering a cold electron fluid and a vortex-like hot electrons. It is found from some numerical results that the parameter β（the ratio of the free hot electron temperature to the hot trapped electron temperature） effects on the amplitude and the Width of the electron acoustic solitary waves （EASW）. It can be indicated that the free hot electron temperature and the hot trapped electron temperature have very important effect on the characters of the propagation for the EASW.

Numerical Simulation Using Boundary Element Method of the Mechanism to Enhance Heat Transport by Solitary Wave on Falling Thin Liquid Films

A boundary element method has been developed for analysing heat transport phenomena in solitary wave on falling thin liquid films at high Reynolds numbers. The divergence theorem is applied to the non-linear convective volume integral of the boundary element formulation with the pressure penalty function. Consequently, velocity and temperature gradients are eliminated, and the complete formulation is written in terms of velocity and temperature. This provides considerable reduction in storage and computational requirements while improving accuracy. The non-linear equation systems of boundary element discretization are solved by the quasi-Newton iterative scheme with Broyden's update. The streamline maps and the temperature distributions in solitary wave and wavy film flow have been obtained, and the variations of Nusselt numbers along the wall-liquid interface are also given. There are large cross-flow velocities and S-shape temperature distributions in the recirculating region of solitary wave. This special flow and thermal process can be a mechanism to enhance heat transport.

Spherical Kadomtsev-Petviashvili Solitons in a Suprathermal Complex Plasma

The nonlinear aspects of nonplanar dust acoustic (DA) solitary waves are investigated in an unmagnetized complex plasma comprising of cold dust grains,kappa-distributed ions as well as electrons.The nonplanar DA solitons are studied based on the reductive perturbation technique.It is shown that the evolution of DA solitons is governed by a spherical Kadomtsev-Petviashvili (sKP) equation and then the impact of suprathermality on the spatial structure as well as the nature of DA soliton is studied.It seems that the properties of DA solitons in nonplanar geometry are quite different from that of the planar solitons.