A Large Deviation Principle of Retarded Ornstein-Uhlenbeck Processes Driven by Lévy Noise

In this article, we develop a large deviation principle (LDP) for a class of retarded Ornstein-Uhlenbeck processes driven by Lévy processes. We first present a LDP result for time delay systems driven by cylindrical Wiener processes based on the large deviations of Gaussian processes. By using a contraction technique and passing on a finite-dimensional approximation, an LDP is obtained for stochastic time delay evolution equations driven by additive Lévy noise, whose solutions are generally not Lévy processes any more.     

基于CDIO导向的微项目驱动交叉混合教学模式——以“日化用品制造技术”教学为例

分析了传统教学模式的优缺点,运用CDIO理念导向的工程教育模式构建了融合教学目标和教学内容的微项目,教师的“教”和学生的“学”与“做”交叉混合进行,形成了一种新的积极高效的教学模式,并在“日化用品制造技术”的教学中尝试开展了这种新的教学模式。实践表明在这种新的教学模式下,学生的学习积极性得以充分调动,学习效果有一定程度的提高,该教学模式有积极的现实意义。     

Effect of surface tension‐driven flow on BaB2O4 crystal growth from high temperature melt‐solution

The surface tension driven‐flow in BaB₂O₄ (BBO) melt‐solution is visualized by differential interference microscope coupled with Schlieren technique, and the streamline of the steady thermocapillary convection is found to be in form of an axially symmetric pattern. Based on the observation of BBO crystal rotation caused by the convective vortex, the widths of interfacial concentration, heat and momentum boundary layer are calculated. The effect of thermocapillary convection on boundary layer thickness is also investigated. Results show that the width of boundary layer decreases linearly with the increasing of dimensionless Marangoni number. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

利用参量驱动法实现Bragg声光双稳系统的混沌同步

对混沌同步方法进行了研究,利用参量驱动法实现了两个混沌系统的同步.以Bragg声光双稳系统为例进行仿真模拟,验证了这种方法的有效性.仿真模拟结果表明：当外加驱动信号作用于两系统的某个被驱动参量,两个初始条件不同的Bragg声光双稳系统误差变量很快平稳地趋于零,说明该同步方法是快速有效的.     

Thermo-Magneto-Electric Currents with Dynamical Magnetization Inhomogeneities

We study the effect of potential and thermal gradient induced non-equilibrium magnetization in quasi 1-d itinerant magnets. A semi-phenomenological theory is employed in conjunction with the drift-diffusion model for this study. Using the methods of non-equilibrium thermodynamics, we derive the transport currents corresponding to charge, heat, and magnetization flows in the presence of non-equilibrium magnetization textures.It is shown how time-dependent magnetic textures give rise to charge and thermalcurrents even in the absence of external potential and thermal gradients through spinpumping.The presence of dynamical textures also affect the thermodynamic parameters of the system. As an application, we consider the case of a helimagnet.     

磁驱动准等熵平面压缩和超高速飞片发射实验技术原理、装置及应用

利用脉冲大电流产生随时间平滑上升的磁压,实现对样品的准等熵平面压缩和超高速飞片发射,是近十年来发展和完善起来的一种新型的强动态斜波加载技术(ramp wave loading).本文简述了其原理、加载装置及数据处理方法等方面的研究进展,同时着重评述利用该技术和方法开展高压物态方程、材料动力学响应方面的研究进展,并对该技术在冲击动力学、天体物理和高能量密度物理等方面的应用前景进行了展望.      

Czerny-Turner型双光栅单色仪的波长驱动与波长校准研究

单色仪在实际光谱测量前需要进行波长校准。文中分析了波长驱动原理,并推导了Czerny-Turner双光栅单色仪出射波长与步进电机脉冲数的关系式。在此基础上进行了波长校准实验。使用低压汞灯作为校准光源,在紫外波段和可见波段蓝端,扫描多条低压汞灯特征谱线,得到单色仪的指示波长与信号强度的关系数据。计算出单色仪出射这些谱线时使用的波长修正量。最后使用曲线拟合方法得到250 nm～450 nm光谱范围内单色仪出射任意波长时对应修正量的计算式。波长校准保证了单色仪的波长准确性。     

Analytical solutions for a doubly driven two-level atom

We have deduced analytical solutions of an energy level diagram of the doubly driven/dressed atom for a two-level atom exposed to a strong near-resonant bichromatic laser field in a special case, i.e., the bichromatic field with frequencies ω1 and ω2, and Rabi frequencies ?1 and ?2, in which the first coupling field of ?1 acts on the bare atomic levels, and then the resulting singly dressed states are driven by the second coupling field of ?2, thus resulting in the doubly dressed atom.We have measured the probe absorption spectra of a doubly driven two-level atom. The system consists of 52S1/2, F= 2 and 5~2P_(3/2), F'= 3 states of ~(87)Rb atoms in a magneto-optical trap(MOT) as well as the cooling/trapping beams and an additional coupling field. As for the spectroscopic properties of the doubly driven two-level atom, theoretical analytical solutions are in general agreement with the experimental spectrum as a whole.     

偏瘫患者辅助下肢外骨骼设计与仿真分析

针对偏瘫患者外骨骼康复机器人降低外骨骼质量的要求,设计了一种辅助下肢外骨骼机器人,采用柔索驱动的膝关节,具有结构简单,质量轻的特点。同时利用ADAMS建立了外骨骼关节柔索驱动的动力学模型,绳索模块建立了柔索驱动模型,通过Ariel生物运动分析软件,采集髋、膝、踝关节运动数据,运用Spline函数进行了仿真分析。经过仿真分析柔索驱动在上台阶运动过程中的不同拉簧预紧力和拉簧刚度下传动特性和驱动力矩,为进一步研究设计下肢外骨骼提供依据。