双反射技术对自由射流三维速度场的测量及显示

应用摄影测量和图像处理技术对自由射流的三维速度场进行了ＰＩＶ测量。构造了一种全新的双反射测量技术，使得二维测量中的多点同步和空间定位得到解决和提高。在精确计算了水与空气的折射关系之后，两幅像片间的同名点寻找更加可靠。重建和再现了ＰＩＶ中射流的连续三维瞬态粒子分布场和速度矢量场。     

单边自由的固支岩板黏弹性行为分析及其应用

利用黏弹性理论对单边自由的固支岩板的黏弹性力学行为进行了分析研究，重新导出了相空间中黏弹性参数的变换关系式，并利用此式建立了单边自由的固支岩板的广义Kelvin黏弹性分析格式，将其应用于某层状岩体洞室顶板的变形特性分析．计算表明，其与实际勘察结果比较接近，可供工程实际应用参考．     

有面内张力和剪力的四边支承各向异性平行四边形板振动、屈曲和弯曲的精确解

给出了弹性地基上四边支承的各向异性平行四边形板在面内张力和剪力作用下自由振动、屈曲和弯曲问题的精确的解析解。此解是利用叠加法得到的重富立叶级数解。与现有结果的比较验证了解的精确性。并给出了一些固定边和简支边组合的多种倾斜角的平行四边形板的自由振动、屈曲和弯曲的数值结果。     

用局部Petrov-Galerkin法分析薄板自由振动

利用薄板振型方程的等效积分弱形式和对振型函数采用移动最小二乘近似函数进行插值，本文进一步研究了无网格局部Petrov-Galerkin方法在薄板自由振动问题中的应用。它不需要任何形式的网格划分，所有的积分都在规则形状的子域及其边界上进行。在插值近似时，采用虚拟-实际节点值变换方法直接引入本质边界条件。通过数值算例和与其他方法的结果进行比较，表明无网格局部Petrov-Galerkin法求解弹性薄板自由振动问题具有收敛性好、精度高等一系列优点。     

自由正交异性矩形厚板的动态稳定

对在一条边上作用着均匀分布的非保守跟随力的四边自由正交异性矩形厚板的动态稳定进行了分析，通过把位移和剪力展成重傅立叶级数解，把微分方程简化成了代数方程。计算表明厚度的微小变化会引起颤振载荷明显的减小。这个明显减小是因为存在剪切变形。     

NEW ALGORITHM OF COUPLING ELEMENT-FREE GALERKIN WITH FINITE ELEMENT METHOD

IntroductionMeshless methods, as a special numerical method, originated from1970s. Since thediffuse element method was proposed by Nayroleset al.[1]in1992, the meshless methodshave received wide attentions in the mechanics area, and have shown obvious adv…     

Electron Transfer Between Molecules: Study with Langevin Equations

In this paper, we investigate the electron transfer （ET） in donor-acceptor model. The Langevin equation with random forces is used. The oscillations of the primary states observed in experimental data have been shown with this approach. And other features on the dependence of the rate of ET on temperature, free energy, and reorganization energy have also been clearly shown.     

The Phase Stability,Thermodynamics Properties and Electronic Structures of L12-Type Al3Sc and Al3Y under High Pressures

The phase stability, thermodynamics properties and electronic structures of L12-Al3Sc and Al3Y compounds under pressure up to 40 GPa are investigated by using first-principles within a local density approximation. The results of formation energies show that Al3Sc is more stable than Al3 Y and the stability of Al3Sc will be better with the increasing pressure. The Gibbs free energy, heat capacity, Debye temperature and thermal expansion coefficient are also investigated. The decreasing density of states at the Fermi level and the strengthening Sc/Y-d orbital hybridization with Al （s, p） under high pressure lead to the observed increase of the structural stability for L12-Al3Sc and Al3 Y under pressures.     

Recovery of the free field in noisy environment by using the spherical wave superposition method

To remove the scattering effect of the disturbing sound on the target source when implementing nearfield acoustic holography in a non-free field, a free field recovery technique based on the spherical wave superposition method is proposed. In the method, the sound field separation technique based on the spherical wave superposition method is first used to separate the incoming and outgoing fields, and a further step for separating the radiated and scattered fields is performed by utilizing the surface admittance of the target source as the boundary condition. The technique makes it possible to correctly identify noise sources in a non-free sound field. The basic principle of the technique is described firstly, a method for choosing the optimal number of spherical wave expansion terms is given, and two numerical simulations are used to demonstrate the validity of this technique. It is shown that, for the lower frequency, the scattering effect can be neglected, and the radiated field of the target source can be obtained by the sound field separation technique, however, as the increasing of the frequency, the scattering effect cannot be neglected, and the free field recovery technique has to be used to obtain the radiated field of the target source.     

基于自由曲面透镜结构的紫外发光二极管固化系统光学设计

传统印刷业中用于固化的光源多采用高压水银灯和金属卤素灯等,传统光源的紫外固化技术已经趋于成熟,不过由于光源本身和光学系统的局限,它们会聚出来的线形光线辐照度较低,且光场均匀度不够高,因此固化效率不够高。提出一种自由曲面透镜的设计方法,将发光二极管灯源和自由曲面透镜结合,可以有效实现光线聚焦的效果,提高光效和均匀性。使用三维机械设计软件SolidWorks设计透镜的初始结构,将透镜模型导入光学优化软件LightTools中对透镜进行光线追迹模拟。通过建立目标函数,执行优化方案,对出射光的均匀度、辐照度不断进行优化,实现出射光为高亮度、高均匀度的线形光。