另一种用物理摆测重力加速度的方法

本实验针对实验室用物理摆的特性,设计出另一种用物理摆测量重力加速的方法。该方法的核心思想是找出周期与转动惯量的关系。     

Variable centroid control scheme over hypersonic tactical missile

This paper presents a brand-new tactical missile control scheme—variable centroid vector control according to the international highlight in the field of missile control and the research status of hypersonic missile control in China. Four critical problems related with the new control method are included: improving phase control in the spinning missile single-channel control; establishing variable centroid controlled spinning missile attitude dynamics equations; analyzing variable centroid control strategies and analyzing the stability of the controlled missile and implementing robust control. The achievements and results obtained are valuable and helpful to the theoretical explorations and engineering applications.     

A study of fringe pattern trace and analysis

In this paper,the gometric center and centroid method are suggested to tracecenter location of a close fringe pattern.The fringe pattern of the interferogram is analysed byusing the general Fourier method.The analytic accuracy is controlled by using P-test methodof statistics.The analytic accuracy and sampling speed of the fringe pattern depend on thequality of the interferogram and the numbers of the sampling points.     

Molecular dynamics with quantum statistics: time correlation functions and weakly bound nano-clusters

An account of recent developments in the study of molecular dynamics with the inclusion of quantum exchange effects is presented. Approaches for quantum dynamical calculations are reviewed and the determination of time correlation functions is a special point of focus. It is shown that the exact basis set techniques can be used to perform highly accurate calculations but are restricted to relatively small systems since computational cost scales exponentially with system size. Alternate formulations can be introduced to circumvent this problem, and semi-classical initial value representation and Feynman path centroid approaches are considered. It is then showed that from a practical point of view, for complex bosonic systems such as doped helium clusters, Quantum Monte Carlo techniques can currently be used for the calculation of quantities of experimental interest. A perspective on future prospects for the calculation of real time correlation functions of bosonic nano-scale systems is presented     

时频特征的海豚发声端点检测方法研究*

为在复杂的海洋环境噪声场中检测出目标海豚的某类声信号,设计了一种基于海豚声学特征的端点检测方法。根据海洋环境中噪声能量大且分布频率范围广,而海豚声音的时频特征具有持续时间短,、频率高且集中,、发声行为持续时间长的特点,将采集到的海洋声音进行分帧,计算单帧信号短时能量、谱质心和谱质心二阶偏移率,当海豚发出声信号时,谱质心和能量相应发生突变,截取发生突变的信号实现端点检测。通过与门限法等其他常见端点检测方法进行对比,结果表明,此方法在低信噪比的海洋环境下对单一海豚的某一类声信号检测准确度更高,同时具有较强的抗干扰能力。     

The exopolyhedral ligand orientation (ELO) in 3‐(nitrato‐κO)‐3,3‐bis(triphenylphosphane‐κP)‐3‐rhoda‐1,2‐dicarba‐closo‐dodecaborane(11) dichloromethane 2.2‐solvate

In the title compound, [Rh(C₂H₁₁B₉)(NO₃)(C₁₈H₁₅P)₂]·2.2CH₂Cl₂, studied as a 2.2‐solvate of what was assumed to be dichloromethane, the nitrate ligand lies cis with respect to both cage C atoms. Accordingly, the compound displays a pronounced preferred exopolyhedral ligand orientation (ELO) which is traced to both the greater trans influence of the cage B over the cage C atoms and the greater trans influence of the triphenylphosphane ligands over the nitrate ligand. The overall molecular architecture therefore agrees with that of a number of similar 3‐L‐3,3‐L′₂‐3,1,2‐closo‐MC₂B₉H₁₁ species in the literature.     

带通红外比色滤波测温技术研究

提出可精确测量中低温物体温度的带通比色滤波测温理论,利用该理论,搭建了相应的实验装置。对装置所用的器件进行精确标定,并利用数值函数对测试得到的离散点数据拟合后,用面源黑体在５０℃～４００℃范围对该实验装置进行了测温实验验证,实验结果表明,该实验装置在不需知道目标发射率的情况下,能精确测量物体的真实温度,因此,验证了提出理论的正确性与所建立测温系统的可行性,对中低温物体真实温度的测量研究具有重要意义。     

基于体视显微镜的测量系统标定研究

微观三维变形测量系统在工程上有广泛的应用。本文构建了体视显微镜双相机微观图像采集与测量系统,可以实现对微小物体形貌、位移、变形的全场测量。微观三维变形的测量精度与成像系统的畸变模型存在密切的关系。本文采用了考虑多种不确定情况的畸变模型,能很好地表达体视显微镜测量系统的成像误差,并设计了点阵式标定模板和精密的平动平台,实现了基于Tsai标定的自动标定算法。实验表明,体视显微镜测量系统可以在各种放大倍数下稳定工作,标定的精度得到很大的提高,并给出了在不同放大倍数下对规则圆柱体的形貌和直径的测量结果。     

有限单元质量质心集中方法的探讨

提出利用单元质量质心集中方法来优化单元惯性效应表征、改善单元力学效应匹配的 思想: 将单元质量质心集中能够建立精确描述单元质点系惯性效应的动力学方程, 进而达到 优化单元惯性效应表征以及改善单元惯性和变形两种力学效应匹配的目的. 本文通过一维问 题的频散效应分析等对该方法的有效性进行了详细的分析和验证.     

The Decomposition and Uniqueness of $n$-Lie Superalgebras

In this paper, the definitions and some properties of $n$-Lie superalgebras are presented. Our main aim is to study the decomposition and uniqueness of finite dimensional $n$-Lie superalgebras with trivial center. According to the decomposition of $n$-Lie superalgebras, we obtain the decomposition of inner derivation superalgebras and derivation superalgebras respectively. Furthermore, we discuss some properties about the centroid of $n$-Lie superalgebras, so we can see its application in the decomposition of $n$-Lie superalgebras.