表面谱学

十五年来表面分析取得了很大的进展,其中表面谱学的发展及其应用起了重要作用。本文试图介绍表面光谱分析中的一些基本概念以及它们在表面科学中能够解决的一些重要问题。实际上,我们是想给读者提供一些表面分析中的基本技术。文中所涉及的例子都取自国际商用机器公司ThomasJ·Watson 实验室。     

猝灭式染料激光器理论研究

理论上研究了由准分子激光泵浦的猝灭式染料激光器的猝灭机理，对于一些具体的泵浦情况，通过激光速率方程理论上探讨了激光器的猝灭效果，并且对激光器的一些重要参数进行了一些研究。     

软物质主要理论综述

本文主要讨论了软物质体系的一些主要理论,如弹性理论、相变理论、标度理论、自洽场理论、颗粒物质理论的发展历史和现状,同时讨论了熵在软物质体系中的作用等.软物质体系中还有一些重要的动力学理论,如黏性问题、扩散问题、介面波的运动等问题均没有在本文中提及,这些领域中也有一些软物质体系重要的理论研究工具和手法.     

简单变换 突现实质

 物理学是以实验为基础的学科。物理实验教学不仅是物理教学的重要内容,而且每个物理实验总是体现特定的物理实质。因此,培养学生透过实验现象抓住实验本质的能力尤为重要。教学中适时地利用一些身边容易找到的物品和简易装置来替换一些实验装置,不仅能消除许多学生对实验的神秘感,而且有时更能简单明了地突出实验的物理实质。下面以笔者在教学中常用的一些替换来举例说明。     

激光发明四十年

扼要介绍了激光的发明、特点和激光器的发展,及激光的一些重要应用     

自制教具系列化 — — — 以食盐水为核心的教具及实验开发

自制教具在物理教学过程中具有重要的作用, 但自制教具也存在着一些困难. 通过以食盐水为例, 阐 述以某一核心资源进行自制教具系列化和实验开发的一些参考路径     

中性第二配体对邻氨基苯甲酸铽络合物荧光性能的影响

第二配体对邻氨基苯甲酸铽络合物荧光性能的研究,得到一些重要的结果。     

美国科学精英与现代情报收集

20世纪90年代以来，随着美国政府一些机密文件的解密以及一些科学家的纪念性撰文陆续披露了美国科学家在美国国家安全、现代情报收集方面所起的重要作用。本文以讲故事的方式介绍这段历史。     

冷原子吸收法测定水中汞的改进

汞是环境监测中的一个非常重要的项目，目前多采用冷原子吸收法测定。本文对采用该法测定水中微量汞的一些操作条件、内容等作一些改进，以提高分析结果的准确度和精密度。     

量子关联

量子纠缠是量子信息处理过程中的重要资源,也是量子力学与经典力学本质区别的一个重要特征.最近随着量子信息理论的不断发展,人们发现可分态中也可以存在非经典的量子关联,量子纠缠只是量子关联的一部分.而且这种非纠缠的量子关联可能在一些量子信息处理过程中起到重要的作用.文章介绍了量子关联最近所取得的一些研究进展,特别是量子关联在各种消相干环境下的演化规律等.     

Faithful quantum secure direct communication protocol against collective noise

An improved quantum secure direct communication (QSDC) protocol is proposed in this paper.Blocks of entangled photon pairs are transmitted in two steps in which secret messages are transmitted directly.The single logical qubits and unitary operations under decoherence free subspaces are presented and the generalized Bell states are constructed which are immune to the collective noise.Two steps of qubit transmission are used in this protocol to guarantee the security of communication.The security of the protocol against various attacks are discussed.     

约束对Birkhoff系统Noether对称性和守恒量的影响

研究约束对Birkhoff系统的Noether对称性和守恒量的影响．首先，建立了Birkhoff系统的运动微分方程．其次，给出了系统Noether对称性的判据．然后，讨论了受约束作用后，Birkhoff系统的Noether对称性发生的变化，并给出了系统的Noether对称性以及守恒量保持不变的条件．最后，举例说明结果的应用． 关键词： 分析力学 Birkhoff系统 约束 Noether对称性 守恒量     

Calculated correlations between material parameters and electro-optical performance of twisted nematic displays

Computer calculations of the optical transmission of TN-LCDs as a function of the applied voltage are presented. In particular, the wavelength and angular dependence of half transmission voltages and sharpness of transmission curves are examined. Furthermore the lowest relaxation rates of the linearized dynamical equations, neglecting backflow effects are calculated. The dielectrical anisotropy and the elastic parameters are varied systematically in the calculations over ranges that actually occur in nematics. Although the results are too complex to be condensed in simple general statements they are helpfull in designing optimal nematic mixtures for a given display application.     

Aerial Video Trackers Review

Target tracking technology that is based on aerial videos is widely used in many fields; however, this technology has challenges, such as image jitter, target blur, high data dimensionality, and large changes in the target scale. In this paper, the research status of aerial video tracking and the characteristics, background complexity and tracking diversity of aerial video targets are summarized. Based on the findings, the key technologies that are related to tracking are elaborated according to the target type, number of targets and applicable scene system. The tracking algorithms are classified according to the type of target, and the target tracking algorithms that are based on deep learning are classified according to the network structure. Commonly used aerial photography datasets are described, and the accuracies of commonly used target tracking methods are evaluated in an aerial photography dataset, namely, UAV123, and a long-video dataset, namely, UAV20L. Potential problems are discussed, and possible future research directions and corresponding development trends in this field are analyzed and summarized.     

光学合成孔径系统的光束控制

本文给出真空中光学合成孔径系统光束控制的物理模型。计算机数值模拟结果与理论分析吻合。另外，对孔径的活塞型和倾斜型误差的影响也进行了探讨。     

亲水性材料固相萃取-紫外导数光谱法检测血中茚满二酮灯抗凝 …

本文报导了血中茚满二酮类抗凝血杀鼠剂敌鼠、氯敌鼠、杀鼠酮的亲水性材料固相萃取－紫外导数光谱检测法。血样用pＨ５缓冲液等体积稀释后加于西雷脱硅藻土柱上,柱用乙酸乙 酯洗脱,将洗脱液挥发干净,剩余物用pＨ１０缓冲液溶解,测定所得溶液的二阶导数光谱进行定性和定量分析。三种杀鼠剂以１０mg／Ｌ的量加于空白血中测得萃取率为８５％以上,血中三种杀鼠剂的检出限低于２ｍｇ／Ｌ。萃取中亲水性硅藻土可用硅胶和氧化铝代替,     

Triaxial Shape,Signature Splitting,and Shape Coexistence in 127,129,131Nd

Signature splitting and shape coexistence at high spin in the neutron deficient nucleus ¹²⁹Nd are investigated with the configuration-dependent cranked Nilsson-Strutinsky approach. The calculated bands are compared with the observed signature partner bands and very good agreement results at high spin are obtained. The observed deformed bands are confirmed as normal and highly deformed and their properties are explained theoretically. Terminating states in ¹²⁹Nd and other terminations are predicted. There is shape coexistence within the same configuration from low-spin states to high-spin states. Possible normal and highly deformed bands with rotation around the intermediate principal axis in several interesting configurations of ¹²⁹Nd are discussed. The experimental results for ¹³¹Nd are simply discussed and the calculated bands are in good agreement with observed bands at high spin. Triaxial shapes in ¹²⁷Nd with a triaxial deformation of γ～-12^º are predicted and should be observed experimentally. The value of negative γ of π(h_11/2)⁴ν(h_11/2)⁷ configuration increases with neutron number increasing in ^127,129,131Nd. The triaxial shape evolutions with neutron number increasing in ^127,129,131Nd and in ^{126,128,130,132}Pr are explained by the strong driving force of specified single particle orbitals towards to triaxial shape.     

导板光互连光斑位置偏移的研究

随着人们对信息处理与交换速度和容量提出的更高的要求,出现了光互连．它具有并行处理、传播速度快、信息量大、空间频带宽、串音小和能量损耗低等优点,因此它在光计算机和信息处理领域中成为越来越吸引人的课题［１～４］提出光电结合的计算机系统．实现光－电混合计算．ＳａｕｅｒＦ提出了将电子元件组成的电路板安装在光导板上的方法［５,６］．每个电路板除了包括计算机本身要求的功能外,还装上发射信号的光源和接收信号的探测器,借助全息元件的耦合,以光导板作为光信息交换的通道．这种互连方式传输信息,结合光电优点,利用Ｂｒ…     

The Resonance Phenomena Associated with the Time Asymmetry in Non-Hermitian Quantum Mechanics

Resonances are defined as the poles of the scattering matrix. The poles are associated with the complex eigenvalues of the Hamiltonian which are embedded in the lower half of the complex plane. The asymptotes of the corresponding eigenfunctions are exponentially diverged. Therefore, the resonance eigenfunctions are not embedded in the Hermitian domain of the Hamiltonian. The time asymmetric problem is discussed for these types of non-Hermitian Hamiltonians and several solutions of this problem are proposed.