强激光大气传输中拉曼散射的数值计算

用经典理论推导了强激光大气传输中由于氮的转动受激Ｒａｎｍａｎ散射所造成的对传输功率的限制方程，并计算了光强的阈值，得到了阈光强与激光波长和脉宽的关系；此外，还研究了二维效应和激光脉冲系列通过大气时声子激发的累加效应。     

非傍轴光束的光束质量因子．I特性分析

使用傅里叶变换和施瓦兹不等式证明：非傍轴标量光束的Ｍ２因子存在有一个只能无限趋近、却永远都不可能达到的下限１；并对一些与此相关的问题进行了讨论     

轴向受载的Bernoulli—Euler薄壁梁固有振动和稳定性的理论研究

通过直接求解轴向受载的单对称均匀Bernoulli-Euler薄壁梁单元弯扭耦合振动的运动微分方程,推导了其动态传递矩阵,讨论了轴向载荷的变化对薄壁梁弯扭耦合振动固有频率的影响,并由此得到零频率振动（弹性屈出）发生时相应的轴向载荷,数值结果表明本文方法在其适应范围内是精确有效的。     

A HIGH-ORDER RIGID-FLEXIBLE COUPLING MODEL OF A ROTATING FLEXIBLE BEAM UNDER LARGE DEFORMATION

对在平面内做大范围转动的中心刚体-柔性梁系统的刚柔耦合建模理论进行了深入研究,建立了系统的高次耦合动力学模型. 该动力学模型考虑了柔性梁横向弯曲变形和纵向伸长变形,且在纵向位移中计及由于横向变形而引起的纵向缩短项,即非线性耦合变形项,并保留了与非线性耦合项相关的一些高阶项,最终得到了系统的高次刚柔耦合动力学方程. 由此得到的动力学方程不仅能适用于柔性梁的小变形问题,也同样适用于大变形问题,弥补了一次近似耦合模型在处理柔性梁大变形问题上的不足. 通过与绝对节点坐标法以及一次近似耦合模型的对比验证了高次耦合模型的正确性.     

Exact solution for in-plane static problems of circular beams made of functionally graded materials

Exact analytical solutions of in-plane static problems of circular beams with uniform cross-section made of functionally graded material (FGM) are obtained. Material properties are assumed to be varying arbitrarily through the thickness. The effects of axial extension and shear deformations are considered. The differential equation system is solved exactly using the initial values method. The circumferential stress distribution on the cross-section is also obtained. The results are compared with those of rather complex approaches in the literature, such as elasticity approach, and the comparison shows an excellent agreement. Effects of power law exponent and radius-to-height ratio of the beam on circumferential stress distribution and displacements are investigated.     

多孔功能梯度材料Timoshenko梁的自由振动分析

基于Timoshenko梁理论研究多孔功能梯度材料梁(FGMs)的自由振动问题.首先,考虑多孔功能梯度材料梁的孔隙率模型,建立了两种类型的孔隙分布.其次,基于Timoshenko梁变形理论,给出位移场方程、几何方程和本构方程,利用Hamilton原理推导多孔功能梯度材料梁的自由振动控制微分方程,并进行无量纲化,然后应用微分变换法(DTM)对无量纲控制微分方程及其边界条件进行变换,得到含有固有频率的等价代数特征方程.最后,计算了固定-固定(C-C)、固定-简支(C-S)和简支-简支(S-S)三种不同边界下多孔功能梯度材料梁自由振动的无量纲固有频率.将其退化为均匀材料与已有文献数据结果对照,验证了正确性.讨论了孔隙率、细长比和梯度指数对多孔功能梯度材料梁无量纲固有频率的影响.     

Structure and optical properties of self-assembled InAs/GaAs quantum dots with In0.15Ga0.85As underlying layer

A high density of 1.02×10¹¹ cm⁻² of InAs islands with In_0.15Ga_0.85As underlying layer has been achieved on GaAs (1 0 0) substrate by solid source molecular beam epitaxy. Atomic force microscopy and PL spectra show the size evolution of InAs islands. A 1.3 μm photoluminescence (PL) from InAs islands with In_0.15Ga_0.85As underlying layer and InGaAs strain-reduced layer has been obtained. Our results provide important information for optimizing the epitaxial structures of 1.3 μm wavelength quantum dots devices.     

与q形变玻色算符逆算符相关的相干态及其量子统计性质

讨论了ｑ形变玻色算符的广义逆算符作用于ｑ－相干态所得到的两类量子态的数学及量子统计性质。结果表明，ｑ－相干态的光子激发态不存在压缩但呈现反聚束效应，而ｑ－相干态的光子湮灭态却存在压缩但不呈现反聚束效应。     

Beam collimation for CSNS/RCS

The current design of the CSNS/RCS beam collimation system consists of a two-stage betatron collimation and a single momentum collimator. This paper summarizes various aspects of collimator design, including collimation principle and layout, material choice and collimator mechanical structure, etc. At last,radiation and thermal analysis are carried out to illustrate the feasibility of the current beam collimation scheme.     

SU(1, 1) and SU(2) Perelomov number coherent states: algebraic approach for general systems

We study some properties of the SU(1, 1) Perelomov number coherent states. The Schrödinger's uncertainty relationship is evaluated for a position and momentum-like operators (constructed from the Lie algebra generators) in these number coherent states. It is shown that this relationship is minimized for the standard coherent states. We obtain the time evolution of the number coherent states by supposing that the Hamiltonian is proportional to the third generator K₀ of the su(1, 1) Lie algebra. Analogous results for the SU(2) Perelomov number coherent states are found. As examples, we compute the Perelomov coherent states for the pseudoharmonic oscillator and the two-dimensional isotropic harmonic oscillator.