Strongly enhanced mode selection in a thin dielectric-coated layered microcavity laser

Strong mode selection through an enhanced interferential coupling effect was observed in a thin dielectric-coated layered cylindrical microcavity laser. The strong coupling effect was induced owing to an enhanced reflectivity of around 50% at the dielectric-coated inner boundary of a fused silica capillary filled with a dye-doped liquid. At an optimized coating thickness of about 0.4 microm, the lasing peaks appeared only at the wavelengths corresponding to the constructive interference condition, whereas those from a bare capillary were weakly modulated.     

Improved method for loss measurements in planar waveguides

A method employing an isosceles prism and a right-angle one is developed for loss measurement in planar waveguides. During the measuring process, the isosceles prism is fixed and the right-angle prism fixed on the waveguide slides by following the waveguide. Only by adjusting the gap thickness we can realize the loss measurement in planar waveguides. The method is demonstrated with an Ag/Na ion-exchanged waveguide fabricated on BK7 glass from AgNO₃ melt diluted with NaNO₃ (mass ratio 1:9), with the condition of 4 h and . The experimental results show that the method has the advantages on convenient operation, accurate results and no required end polishing.     

纳米载体负载声敏剂的研究进展和挑战

声动力治疗是将低频超声与声敏剂相结合的非侵入性肿瘤治疗方法,由于其副作用小、治疗深度深等优点,受到科学家们的重视。有机声敏剂作为初代声敏剂已经被研究多年,但是其水溶性差、无法在肿瘤部位大量聚集等缺陷阻碍了其声动力应用。快速发展的纳米技术为许多问题的解决提供了新的思路,尤其利用纳米载体负载声敏剂,可以解决有机声敏剂水溶性差、容易被提前释放等问题,实现药物靶向作用,为声动力治疗与其他疗法结合提供平台,进一步发挥声动力治疗疗效。因此,该文总结了纳米载体负载有机声敏剂用于声动力治疗的相关研究,着重介绍纳米载体在声动力治疗中的研究进展及相关机理,指出现存问题,最终希望可以总结出用于声动力治疗的纳米载体的共性,为今后研究提供帮助。     

New Sixth-Order Compact Schemes for Poisson/Helmholtz Equations

Some new sixth-order compact finite difference schemes for Poisson/Helmholtz equations on rectangular domains in both two- and three-dimensions are developed and analyzed. Different from a few sixth-order compact finite difference schemes in the literature, the finite difference and weight coefficients of the new methods have analytic simple expressions. One of the new ideas is to use a weighted combination of the source term at staggered grid points which is important for grid points near the boundary and avoids partial derivatives of the source term. Furthermore, the new compact schemes are exact for 2D and 3D Poisson equations if the solution is a polynomial less than or equal to 6. The coefficient matrices of the new schemes are $M$-matrices for Helmholtz equations with wave number $K≤0,$ which guarantee the discrete maximum principle and lead to the convergence of the new sixth-order compact schemes. Numerical examples in both 2D and 3D are presented to verify the effectiveness of the proposed schemes.     

热结构稳态响应的耦合灵敏度分析方法

研究结构稳态热变形和热应力的灵敏度分析方法，给出了直接法和伴随法两种算法。考虑了温度场的耦合作用，在直接法中需要计算温度场对设计变量的导数，在伴随法中需要计算热载荷对温度场的导数。对尺寸和形状两类设计变量的灵敏度分析算例，验证了本文方法的精度。伴随法在应用程序中的实现，为大型结构优化提供了高效率的灵敏度计算方法。     

固体发动机保险机构在高温高压下的实验研究

针对固体发动机部件保险机构所出现破现象,对其进行了激光散斑和电阻应变法联合测试。由于保险机构在高温和高压环境下工作,材料有蠕变现象,出现较大的热变形,传统的光我法实施,发展了一种叠合散斑技术,使之能够对大变形进行非接触式测量,在实验室测试的基础上,对保险机构进行了热容器试验,测量了点火后应变随时间的变化规律。实验结构发现,在保险机构机体上存在着一个接近破环应力的高危应力区,这是保险机破坏的主要因素     

结构优化设计的KFD方法及其在电除尘器本体结构优化中的应用

电除尘器本体结构优化设计是一个规模大,设计变量数多而具有相当难度的几何可调和拓扑可调优化设计问题。对这样一个大型复杂的结构优化问题,本文在文[1]的工作基础上,充分利用结构的力学特性,应用有效设计变量的概念,建立了不用求偏导数且不必解线性规划的可行方向法—KFD方法。该方法具有收敛速度快、占用内存少的优点,比通常ε有效约束可行方向法提高速度数十倍。实际应用的结果表明文中的方法是很有效的。     

Complete Asymptotic Expansions of Solutions of the System of Elastostatics in the Presence of an Inclusion of Small Diameter and Detection of an Inclusion

We consider the system of elastostatics for an elastic medium consisting of an imperfection of small diameter, embedded in a homogeneous reference medium. The Lamé constants of the imperfection are different from those of the background medium. We establish a complete asymptotic formula for the displacement vector in terms of the reference Lamé constants, the location of the imperfection and its geometry. Our derivation is rigorous, and based on layer potential techniques. The asymptotic expansions in this paper are valid for an elastic imperfection with Lipschitz boundaries. In the course of derivation of the asymptotic formula, we introduce the concept of (generalized) elastic moment tensors (Pólya–Szegö tensor) and prove that the first order elastic moment tensor is symmetric and positive (negative)-definite. We also obtain estimation of its eigenvalue. We then apply these asymptotic formulas for the purpose of identifying with high precision the order of magnitude of the diameter of the elastic inclusion, its location, and its elastic moment tensors.     

Benchmark solution of angle-ply piezoelectric-laminated cylindrical panels in cylindrical bending with weak interfaces

The bending problem of a simply supported, angle-ply piezoelectric-laminated cylindrical panel in cylindrical bending with weak interfaces is considered. A general spring-layer model is adopted to describe the weakness of imperfect interfaces. An exact analysis is performed via the state-space approach. A new system of physical variables is introduced and a variable substitution technique is employed to derive a state equation with constant coefficients. Numerical results are given to show the effect of weak interfaces.The work was supported by the National Natural Science Foundation of China (No. 10372088) and by the Korea Institute of Science and Technology Evaluation and Planning.     

地质工程计算机辅助设计支持系统及其应用

地质工程设计具有非结构化、非参数化、非规范化特征,同时,也具有“风险与优化”性和“反馈与可变更”性。仅用一种固定的、程式化的求解方法是不现实的。因此,必须寻求一种非结构化的工具,根据问题的需要,面向目标自动生成求解结构。本文归纳了地质工程设计的基本内容,探讨了基于几何和基于人工智能的计算机辅助地质工程设计。最后,介绍了地质工程设计支持系统在长江三峡链子崖危岩治理工程设计中的应用。