Effect of the reagent vibration on stereodynamics of the reaction O（^1D）＋HF→F＋OH

This paper studies the influence of the reagent vibration on the reaction O(¹D)+HF → HO+F by using a quasi-classical trajectory method on the new \textitab initio ¹A' ground singlet potential energy surface (Gómez-Carrasco et al 2007 Chem. Phys. Lett. 435 188--193). The product angular distributions which reflect the vector correlation are calculated. Four polarization-dependent differential cross sections (PDDCSs) which are sensitive to many photoinitiated bimolecular reaction experiments are presented in the center of the mass frame, respectively. The differential cross section indicates that the OH product mainly tends to the forward scattering, and other PDDCSs are also influenced by the vibration levels of HF.     

Flexural vibration band gaps in thin plates with two-dimensional binary locally resonant structures

The complete flexural vibration band gaps are studied in the thin plates with two-dimensional binary locally resonant structures, i.e. the composite plate consisting of soft rubber cylindrical inclusions periodically placed in a host material. Numerical simulations show that the low-frequency gaps of flexural wave exist in the thin plates. The width of the first gap decreases monotonically as the matrix density increases. The frequency response of the finite periodic thin plates is simulated by the finite element method, which provides attenuations of over 20dB in the frequency range of the band gaps. The findings will be significant in the application of phononic crystals.     

横截性理论在碰撞振动系统结构稳定问题中的应用

本文利用横截性理论研究了碰撞振动系统中的结构稳定问题。讨论了结构稳定、稳定、失稳及分叉之间的关系。     

非化学计量比铌酸钾锂晶体的光谱特征

用顶部籽晶法生长了一批不同组成的铌酸钾锂晶体。利用近红外cw: Ti-sapphire激光研究了三种组成的经过精细抛光的晶体样品的二次谐波性质,结果表明晶体的二次谐波效应与晶体组成密切相关,Li含量越高的样品倍频效率越高。利用红外Raman光谱技术调查了晶体非线性晶格振动特征,分析了晶体中组分离子浓度对晶体红外Raman光谱特征的影响,探讨了组分离子对晶体二次谐波性质影响的原因。结果表明,晶体中位于C格位的Li离子浓度对晶体Raman光谱产生了强烈的影响,低Li含量晶体中[NbO₆]7-八面体所对应的3个Raman特征光谱线没有峰发生分裂;当晶体中Li离子浓度增加时,ν₅所对应的Raman峰有所加宽,ν₂振动模式出现分裂峰,并在100～400 cm-1范围出现小峰数量增多;当Li离子浓度接近铁电相边界时,[NbO₆]7-八面体结构接近解体,ν₅所对应的Raman峰分裂成3个峰,ν₁和ν₂振动模式发生部分分裂,在100～400 cm-1范围小峰更为突出。这些影响的本质在于晶体中Li含量的提高导致晶体中[NbO₆]7-八面体畸变程度加大,与晶体非线性光学性质相一致。     

光致发光光谱研究金刚石光学中心的振动结构

金刚石中不同的缺陷中心具有不同的振动结构. 间隙原子相关中心在离开零声子线165 meV之外存在强且尖锐的局部振动模; 空位相关中心具有很强的振动耦合, 在其零声子线之后出现很强且宽的声子边带, 而在165 meV之外却观察不到局部振动模, 且对于仅涉及一个空位的缺陷来说, 其振动都与一个能量约为42 meV的声子或一个能量约为67 meV的声子或两声子有关.     

BS分子α带系A~2Π→X~2Σ~+及γ带系C~2Π→X~2Σ~+法兰克-康登因子的计算

在双原子分子核运动的薛定谔方程中，计入分子的振转相互作用项，在Ｍｏｒｓｅ势近似下得出的波函数除与振动量子数有关外，还与转动量子数有关。本文用该波函数编程计算了ＢＳ分子α带系Ａ２Π→Ｘ２Σ＋及γ带系Ｃ２Π→Ｘ２Σ＋法兰克－康登（Ｆｒａｎｃｋ－Ｃｏｎｄｏｎ）因子（简称Ｆ－Ｃ因子）。计算中转动量子数的取值由Ｊ＝０至Ｊ＝２００，其结果适用于低温、高温和强激波条件。     

Monte Carlo studies of nuclear many-particle systems

Stochastic evaluation of path integrals provides a useful tool for the study of a variety of nuclear systems which are otherwise not amenable to definitive analysis through perturbative, variational, or stationary-phase approximations. Ground state properties of potential models, such as quantum fluctuations in the density, are examined. Tunneling problems in quantum many-particle systems, such as spontaneous fission and the ground state structure of systems with degenerate vacuua are treated by incorporating one's physical understanding of the essential collective degrees of freedom in the stochastic algorithm. The role of subnuclear degrees of freedom is studied by comparing the exact solution of a simple confining quark model with the solution to a phase-shift equivalent hadronic potential model. This work is supported in part through funds provided by the U.S. Department of Energy (D.O.E.) under contract number DE-AC02-76ERO3069.     

Optical design of adjustable light emitting diode for different lighting requirements

<正>Light emitting diode(LED) sources have been widely used for illumination.Optical design,especially freedom compact lens design is necessary to make LED sources applied in lighting industry,such as large-range interior lighting and small-range condensed lighting.For different lighting requirements,the size of target planes should be variable.In our paper we provide a method to design freedom lens according to the energy conservation law and Snell law through establishing energy mapping between the luminous flux emitted by a Lambertian LED source and a certain area of the target plane.The algorithm of our design can easily change the radius of each circular target plane,which makes the size of the target plane adjustable.Ray-tracing software Tracepro is used to validate the illuminance maps and polar-distribution maps.We design lenses for different sizes of target planes to meet specific lighting requirements.     

斜拉桥模拟试验平台的振动特性测试及分析

以宁波某跨海大桥为原型,结合桥梁激励系统、传感器、数据采集处理系统和拉索-阻尼减振系统,搭建斜拉桥振动试验平台,并模拟不同车辆载荷及行驶速度工况下的拉索振动响应试验;同时,分别利用液压阻尼器和橡胶阻尼器对斜拉索振动的抑制效果进行分析.结果表明,斜拉索振动幅度随车辆行驶速度、载重的增加而变大;橡胶阻尼器对长拉索减振效果明...     

移动随机荷载作用下梁桥非平稳随机振动的PEM-FFT方法

针对移动随机载荷作用下桥梁结构非平稳随机振动问题,建立了一种基于频域分析的虚拟激励-傅里叶变换方法(PEM-FFT)。与通常的非平稳随机振动的时频分析方法不同,提出的方法完全在频域上执行。其主要特色是能够给出随机输入与随机输出的频域关系,表明移动载荷作用下结构非平稳随机振动分析仅需对载荷的确定性移动函数项进行计算。数值算例考虑了等截面/变截面简支梁受移动随机载荷作用的问题,首先与通常的时频分析方法进行对比,验证了PEM-FFT方法的正确性和有效性,进一步讨论了不同结构形式以及不同载荷移动速度对响应演变统计量的影响。