激光能俘获粒子吗?

 随着科学技术的深入发展.特别是六十年代激光诞生,使光学领域发生了一次重大飞跃,它不仅开创了光学技术的新局面,而且几乎没有那一门自然科学不感受到激光的巨大魅力的影响.与此同时,作为对光自身性质的研究,人们对光的力学效应产生了浓厚的兴趣.每个光子具有的动量虽小,但高亮度的激光束所表现出来的动量则可产生令人惊叹的宏观效应.目前已做到将Na原子的运动速度从600m/s冷却到平均速度近似为零.将原子冷却到10^-4K后进一步采用磁陷阱、射频陷阱或激光陷阱等把原子囚禁其中.     

Study on a Cross Diffusion Parabolic System

This paper considers a kind of strongly coupled cross diffusion parabolic system,which can be usedas the multi-dimensional Lyumkis energy transport model in semiconductor science.The global existence andlarge time behavior are obtained for smooth solution to the initial boundary value problem.When the initialdata are a small perturbation of an isothermal stationary solution,the smooth solution of the problem under theinsulating boundary condition,converges to that stationary solution exponentially fast as time goes to infinity.     

THE LARGE TIME BEHAVIOR OF SPECTRAL APPROXIMATION FOR A CLASS OF PSEUDOPARABOLIC VISCOUS DIFFUSION EQUATION

The asymptotic behavior of the solutions to a class of pseudoparabolic viscous diffusion equation with periodic initial condition is studied by using the spectral method. The semidiscrete Fourier approximate solution of the problem is constructed and the error estiation between spectral approximate solution and exact solution on large time is also obtained. The existence of the approximate attractor AN and the upper semicontinuity d(AN,A)→0 are proved.     

Herz接触问题的解的唯一性条件

讨论了接触面为圆面的Ｈｅｒｔｚ接触问题。若压会布是轴对称的，则该接触问题的解必是唯一的。且在上述条件下，该接触问题的积分方程化为两个推广的Ａｂｅｌ积分方程组，此方程组的解便给出此接触问题的解。     

自体静脉移植血管的拉伸实验研究

本文考察了自体移植静脉的纵向应力应变关系。将狗股静脉移植于股动脉，在术后不同时间切取移植静脉进行纵向单轴拉伸实验。结果表明，移植静脉的应力－应变曲线比正常静脉靠近应力坐标轴并在术后逐渐向左移动。这显示了移植血管管壁组织在术后的逐渐硬化。     

对于叶轮机气动弹性力学一个基本假设的讨论

“在一个叶片排中叶片间相角为常数”是叶轮机气动弹性力学至今沿用的基本假设。但事实表明,当颤振发作时,叶片排中各叶片不仅动应力不同,而且叶片间相角亦非常数。解除了此基本假设的约束之后,本文发展了一种新的模型和计算方法。计算结果与实验数据对比表明,当气动弹性失稳时,叶片排中诸叶片动应力之所以不相等,叶片间相角并非常数是一个主要原因。     

SYNTHESIS OF POLYMER—SUPPORTED PALLADIUM CATALYSTS AND THEIR CATALYTIC BEHAVIOR FOR THE SELECTIVE HYDROGENATION OF MESITYL OXIDE

Copolymer of styrene-divinylbenzene in bead from was made by suspension polymerization.After chloromethylation and amination,five kinds of polymeric amines were thus obtained.These polymers were reacted with palladium chloride,and were then reduced.The polymer-supported catalysts synthesized above were used to catalyze the selective hydrogenation of mesityl oxide under reaction conditions of 80℃ and 10kg/cm^2,using methanol as a solvent.The catalytic activity and MIBK(methyl isobutyl ketone) formation selectivity of the catalysts were examined.     

中国古建筑的力与美探析

中国古建筑的力与美探析慎铁刚（天津大学建筑系，天津３０００７２）人们对美学的研究，基本上可以分为２条途径：一是从人文学的角度，比如从哲学、心理学、艺术学等领域来探讨美学上的一些基本理论，有美的实质、美的产生、审美意识等；二是从学科交叉的角度，比如近代...