悬丝耦合弯曲共振法测定金属材料杨氏模量

简要介绍了用悬丝耦合弯曲拱振法测定金属材料杨氏模量实验的意义、实验原理、实验装置以及实验中的若干问题,并提出了一组实验数据供参考。     

在光电效应实验中测量光电管的基本特性

在光电效应测量普朗克常数实验装置的基础上介绍了测量光电管的光频特性、伏安特性和光照特性的实验方法,给出了相应的实验结果,拓宽了实验内容、增强学生综合实验能力。     

对浮力实验和阿基米德实验的改进

通过学生自主实验,提出了相对简易的探究浮力方向的实验方法,同时对阿基米德实验进行了改进。改进后的阿基米德实验降低了实验偏差,实验效果直观、明显。本文还对教材的编排提出了建议和意见。     

夫兰克-赫兹实验的计算机仿真

为了利用现代化的手段改进实验教学，我们研制了F-H实验的计算机仿真系统。该系统以计算机动画技术模拟了F-H实验的各种仪器。学生脱离现实的实验仪器，通过键盘操作完成实验操作。实验中教师专家系统随时进行指导和评估，加深学生对实验原理的理解。该系统把教材、教师指导、实验操作和学生的独立思考熔为一体，增加了实验的趣味性和可重复性，激发了学生做实验的热情，极大地提高了实验教学的效果。     

测量一般长度、微小长度、微小增量的设计性实验

本阐述了力学实验中的长度设计性实验。从实验题目、实验方案的拟订、仪器的配置、测量和操作，给学生提供了较大的空间，调动了学生的独立创造意识。     

HL-2M 实验网络与数据管理系统的设计与实现

HL-2M 网络与数据管理包含了实验网络系统、数据存储与备份系统,以及实验数据库与实验信息管 理系统等。实验网络系统是装置运行的支持骨架,为各子系统提供互联通道和信号传输能力;数据存储与备份系 统为托卡马克实验提供数据的存储管理与容灾备份服务;实验数据库系统为元数据与科学数据提供了高效的检 索、访问与管理;实验信息管理系统为装置各子系统提供了参数配置管理、运行日志记录与运行值守管理,实现 了实验运行管理信息化,提高了实验运行效率。     

物理实验仪器深度开发的试验与探讨

重点讨论实验室中现有物理实验仪器的深度开发,围绕相关的实验内容、实验材料、实验演示传播方式等方面展开探讨和深度开发,利用此方式拓展了物理实验内容,加深巩固了物理实验原理的理解,实现了实验仪器的最大程度利用和更大使用价值的发挥,提高了实验仪器的利用率,在节约能源上起到很好的示范作用。     

人耳听阈曲线的测定实验设计

为了医学生物理实验的改革创新,我实验室引进了BD-Ⅱ-116型听觉实验仪,为学生开设＂人耳听阈曲线的测定＂的医用物理实验,在此给出声强级、听阈曲线、响度等概念,设计目的、实验器材、实验原理、实验内容与步骤等,学生通过本实验掌握了实验理论,同时对医学内容也有了一定了解。     

两个演示实验的改进

本文介绍两个改进了的演示实验,它们具有实验现象直观、明显、观察范围大等特点。一、导体棒切割磁感应线实验导体棒切割磁感应线实验,是大、中学物理教材中讲电磁感应的典型例子。但常见的物理演示实验书中对该实验很少作介绍,这似乎与该实验通常演示效果不佳有关。使用放大器虽然可以改善演示效果,但同时也影响了实验的直观性。     

磁力线图像的固定法

我经过多次的考虑、实验和与同志们的研究,终于将不能挂起来看的磁场实验现象挂起来了。这样一来解决了仪器少不能分组实验的困难,使每个同学都能很清楚的看到实验现象。另外解决了人数多、实验时间不够用和同学们看不清甚至于看不到实验现象的困难,也不至于因同学们集中的看示教实验,影响了课堂秩序。今将我制做磁场的定型实验介绍于     

ICP-AES法测定金属硅中的Al、B、Ba、Ca、Cr、Cu、 Fe、Mg、Mn、Ni、Sr、Ti、V和Zn杂质元素

本文提供了一种测定金属硅中Ｂ,Ｆｅ,Ａｌ,Ｃａ,Ｍｎ等１４个杂质元素的ＩＣＰ－ＡＥＳ方法,在样品处理过程中,加入适量体积的甘露醇能够抑制Ｂ的挥发。用本方法测定了一个国家地球化学标准样（ＧＳＲ－４）,结果令人满意。     

Density functional theory study of structural,electronic,and thermal properties of Pt,Pd, Rh,Ir, Os and PtPdX(X= Ir,Os, and Rh) alloys

The structural, electronic, mechanical, and thermal properties of Pt, Pd, Rh, Ir, Os metals and their alloys Pt Pd X(X= Ir, Os and Rh) are studied systematically using ab initio density functional theory. The groundstate properties such as lattice constant and bulk modulus are calculated to find the equilibrium atomic position for stable alloys. The electronic band structure and density of states are calculated to study the electronic behavior of metals on making their alloys. The electronic properties substantiate the metallic behavior for all studied materials. The firstprinciples density functional perturbation theory as implemented in quasi-harmonic approximation is used for the calculations of thermal properties.We have calculated the thermal properties such as the Debye temperature, vibrational energy, entropy and constant-volume specific heat. The calculated properties are compared with the previously reported experimental and theoretical data for metals and are found to be in good agreement. Calculated results for alloys could not be compared because there is no data available in the literature with such alloy composition.     

Elastic and brittle properties of the B2-MgRE (RE = Sc,Y, Ce,Pr, Nd,Gd, Tb,Dy, Ho,Er) intermetallics

The brittle and elastic properties of the B2-MgRE (RE = Sc, Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er) intermetallics have been investigated using first-principles density functional calculations. The calculated equilibrium lattice constants and enthalpies of formation are in overall agreement with the available experiment and theoretical results. The related physical properties of those compounds are compared with that of ductile YCu. The Fermi energy occurs above a peak in the DOS for B2-MgRE intermetallics, whereas for ductile YCu the Fermi energy occurs near a minimum in the DOS. For B2-YCu, the partial density of states of d-states at the Fermi energy is low, while for B2-MgRE the RE d-states are partially occupied, indicating their important roles in the directional bonding for this material. The Cauchy pressure (C₁₂-C₄₄) and the ratio of bulk to shear modulus B/G are used to assess the brittle/ductile behavior of B2-MgRE and YCu compounds. It can be concluded that the B2-MgRE alloys have brittle behavior. MgSc is the most brittle, and MgHo is the least brittle amongst those alloys.     

纯硒中杂质元素的ICP-AES测定

电感耦合等离子体-原子发射光谱同时测定纯硒中的碲、铅、铋、锑、铜、铁、镍、铝、锡、砷和硼12种元素的含量,优化出各元素的分析波长和分析条件;用基体匹配补偿基体效应,方法简单,快速可靠,样品回收率为94%-107%.     

Stress, strain, and NMR

Experimental and ab initio results that demonstrate the effect of stress on the nuclear magnetic resonance spectra of materials are shown. The design of a cell that generates uniaxial compressive stress is presented, and results on gallium phosphide and lead nitrate single crystals that illustrate the observable results of the stress are shown. Tensors that relate stress and strain to changes in the chemical shielding tensors and the electric field gradient tensors are defined formally. The elements of these tensors are then computed by a density functional theory approach that makes use of planewaves and pseudopotentials. The experimental results are interpreted with the aid of the calculations. Extensions to spinning samples and to the interpretation of optical phenomena in materials are discussed.     

Optoelectronic Devices: Design,Modeling, and Simulation,by Xun Li

A historical survey of the development of solid-state detectors is given, and it is shown why semiconductor detectors are superior to the earlier crystal counters. The physical processes which occur during the detection of nuclear radiation in a solid-state device are considered in detail, and the merits of the reverse-biased semiconductor junction in silicon or germanium are set out. Factors which determine the energy resolution of such a detector are analysed, and also the effects of radiation damage. The preparation of such detectors is not treated in detail, but the physical principles on which the important types of detector depend are described. The final section surveys the field of applications of solid-state detectors in nuclear physics, radiochemical analysis, space research, medicine and biology.     

Band structure,Fermi surface,elastic,thermodynamic,and optical properties of AlZr_3,AlCu_3,and AlCu_2Zr:First-principles study

The electronic properties(Fermi surface,band structure,and density of states(DOS)) of Al-based alloys AlM_3(M=Zr and Cu) and AlCu_2Zr are investigated using the first-principles pseudopotential plane wave method within the generalized gradient approximation(GGA).The structural parameters and elastic constants are evaluated and compared with other available data.Also,the pressure dependences of mechanical properties of the compounds are studied.The temperature dependence of adiabatic bulk modulus,Debye temperature,specific heat,thermal expansion coefficient,entropy,and internal energy are all obtained for the first time through quasi-harmonic Debye model with phononic effects for T = 0 K-100 K.The parameters of optical properties(dielectric functions,refractive index,extinction coefficient,absorption spectrum,conductivity,energy-loss spectrum,and reflectivity) of the compounds are calculated and discussed for the first time.The reflectivities of the materials are quite high in the IR-visible-UV region up to ~ 15 eV,showing that they promise to be good coating materials to avoid solar heating.Some of the properties are also compared with those of the Al-based Ni_3 Al compound.     

电感耦合等离子体发射光谱法测定铝合金中La、Ce、Pr、Nd、Sm

利用ICP—AES仪测定稀土铝合金中微量的La、Ce、Pr、Nd、Sm。试样用酸分解,直接上机测定,对光谱干扰情况和仪器参数的选择进行了研究。实验结果和推荐值核对相符。     

ICP-AES同时测定水中的痕量钼、钴、硼、锑、钒和钛

采用ICP-AES同时测定水中的痕量钼、钴、硼、锑、钒、钛等6种元素。结果表明,各元素检出限为1.5—13μg.L^-1,满足饮用水及其水源水分析要求;空白加标回收率为94.2%—105%,样品加标回收率为90.6%—98.8%,相对标准偏差（n=9）〈2.40%。该方法简便、高效、快速、线性范围宽,适于饮用水及其水源水质分析。     

On Virtual Phonons,Photons, and Electrons

A macroscopic realization of the peculiar virtual particles is presented. The classical Helmholtz and the Schrödinger equations are differential equations of the same mathematical structure. The solutions with an imaginary wave number are called evanescent modes in the case of elastic and electromagnetic fields. In the case of non-relativistic quantum mechanical fields they are called tunneling solutions. The imaginary wave numbers point to strange consequences: The waves are non-local, they are not observable, and they are described as virtual particles. During the last two decades QED calculations of the solutions with an imaginary wave number have been experimentally confirmed for phonons, photons, and electrons. The experimental proofs of the predictions of non-relativistic quantum mechanics and the Wigner phase time approach for the elastic, electromagnetic and Schrödinger fields will be presented in this article. The results are zero time in the barrier and an interaction time (i.e. a phase shift) at the barrier interfaces. The measured tunneling time scales approximately inversely with the particle energy. Actually, the tunneling time is given only by the barrier boundary interaction time, as zero time is spent inside a barrier.