利用湍流廓线获得斜程大气相干长度的实验研究

 用两种方法获得有限高度斜程大气相干长度。一种方法用安置在测量铁塔上的温度脉动仪以及多普勒声雷达测量了大气边界层下部折射率结构常数廓线，用以计算有限高度球面波斜程大气相干长度；另一种方法用系留气球搭载一个点光源，在地面用差分光学系统接收球面波到达角起伏法测量了实时斜程大气相干长度。对实验结果进行了比较和分析，二者都反映了实际大气斜程相干长度的时间变化特点。两种方法结果的相关性比较好，因此两种方法都可以在大气光学传输研究中应用。最后在实验的基础上对湍流廓线计算球面波斜程大气相干长度作了讨论。     

毫米波段高功率绕射辐射振荡器的研究

 提出采用大口径、浅褶皱和短周期分段式慢波结构作为高功率毫米波绕射辐射振荡器的高频系统。采用通用理论对器件的色散特性进行了分析，用PIC方法对整体器件进行了模拟。在此基础上，开展了实验研究工作，测试了器件输出微波功率和频率。初步实验结果与理论分析和PIC模拟结果的趋势基本吻合。     

1~Π态双原子分子中关于Λ量子干涉的微分干涉角(英文)

Sha等在静态池实验中观察到了转动能量转移中的碰撞量子干涉,并且计算了决定跃迁散射截面的积分干涉角(J.Chem.Phys.,1995,102:2772).由于积分干涉角是微分干涉角的平均效应,为了得到更精确的信息,进行了分子束实验.作者文运用含时微扰的一级波恩近似理论,提出了衡量干涉程度的1П态双原子分子中关于Λ量子干涉的微分干涉角.利用各向异性相互作用势计算了其干涉角.得到分子束实验中微分干涉角随实验参数,包括实验温度、碰撞伴、作用距离和转动量子数变化的关系.并且讨论了影响干涉角的各种参数.此理论模型对理解和进行分子束实验是非常重要的.     

提高高分子化学实验效果的尝试

以丙烯酰胺的水溶液聚合为例,探讨如何提高高分子化学实验的作用:一是将验证性实验扩展为研究性实验,即将同一实验内容改变实验条件分给不同组进行,而后汇总讨论;二是引导学生认真观察实验现象,广泛地与生产实际相联系,和后续课程进行衔接,丰富了实验内涵.研究性实验和丰富实验内涵极大地激发了学生学习兴趣与潜能,从而提高了实验效果.     

面向21世纪的大学物理实验的教改实践与思考

本文介绍了作者在大学物理实验课程改革中所做的一些探索 ,阐述了下一步教改的方向与内容     

Effect of structure parameters on forces acting on baffles used in gas–solids fluidized beds

Effects of some important structural parameters, i.e. slat pitch, and layout position, on dynamic forces acting on the baffles were examined in the fluidized bed of FCC particles operating under different superficial gas velocities. The experimental baffles were made of multiple inclined slats. We found that the forces acting on the baffles decreased significantly with reducing pitch between the slats. For the baffles with a small slat pitch, the forces acting on the baffles increased slightly and then decreased with increasing superficial gas velocity, which is very different from the measured results of a single slat or tube immersed in fluidized beds. The different results are greatly related to the appearance of the “gas cushion” beneath the baffles, whose height increases with increasing superficial gas velocity. On the other hand, a region with stronger particle circulation induced by the inclined slat array was observed in the experiments. The slat near the wall and located below the region of downward-flowing particles was found to be subjected to the severest forces. Therefore, the slats located in similar locations of industrial baffles are suggested to be reinforced to increase their structural strength.     

基于邻井反射的偶极横波远探测验证方法

偶极横波远探测技术已成为探测井外地质构造的一种重要测井技术,需要针对偶极横波远探测的验证迫在眉睫。本文利用三维有限差分数值模拟方法,对比和分析了地层界面和相邻充液邻井产生的反射横波幅值的差别,结合现场实例,提出了偶极横波远探测成像测井的验证方法。在此基础之上,进一步分析了不同反射邻井结构时,反射横波幅度的变化情况,结果表明,采用多井联合方式可以有效的增加反射波的幅值,减小非共面产生的散射效应影响。最后,初步建立了两口试验井,测试数据处理结果与理论分析结果吻合,为下一步实验井方案的优选和完善提供了理论和数据支持。     

Solitary waves in longitudinally wrinkled and creased helicoids

Elastic ribbons subjected to twist and stretch handle multiple morphological instabilities, amongst others, the longitudinally wrinkled and creased helicoids are investigated in the present paper as promising periodic nonlinear waveguides. Modeling the ribbon by isogeometric Kirchhoff–Love shells, the first longitudinal buckling mode is recovered numerically and used into the Bloch–Floquet method to obtain dispersion curves. After analyzing the effects of the buckling pattern on the different wavemodes, it is shown that classical linear axial waves interact with bending ones and become dispersive. Additionally, as buckling involves geometrical nonlinearities, the structure is expected to host stable nonlinear waves. Indeed, clear supersonic rarefaction trains are observed experimentally and their characteristics are found in agreement with the weakly nonlinear Boussinesq model.     

The experimental study on the contact process of passive walking

The passive dynamic walking is a new concept of biped walking. Researchers have been working on this area with both theoretical analysis and experimental analysis ever since McGeer. This paper presents our compass-like passive walking model with a new set of testing system. Two gyroscopes are used for measuring the angles of two legs, and ten FlexiForce sensors are used for measuring the contact forces on the feet. We got the experimental data on the passive walking process with the validated testing system. A great emphasis was put on the contact process between the feet and the slope. The contact process of the stance leg was divided into four sections, and differences between the real testing contact process and the classic analytical contact process with no bouncing and slipping were summarized.