基于Web的虚拟实验室技术及其应用

虚拟实验室是指在计算机上应用虚拟现实技术来仿真实际实验的软件系统.分析了虚拟实验室技术的特点,详细介绍了虚拟实验室技术在网络中的应用,并以真实仪器为原型,利用图形化编程软件LabVIEW设计实现了虚拟信号发生器和虚拟示波器,通过网络连接,将信号发生器产生的各种信号在示波器上正确显示出来,实现了基于Web的虚拟实验室.     

基于LabVIEW的虚拟信号发生器和示波器设计

结合部队学员对基本仪器掌握不足的情况,介绍了以图形化编程序言LabVIEW设计的一个虚拟信号发生器和示波器的实例。文中提出了设计要求,具体阐述了设计方法,给出了前面板和设计框图。该虚拟信号发生器和示波器完全满足物理实验中预备实验的要求,有助于学员更好地认识和使用该仪器。     

基于LabWindows/CVI的虚拟实验室研究

现在高校教学实验设备及场地的紧张,为了缓解这个问题,提出了基于LabWindows/CVI平台的虚拟实验室的研究,设计了虚拟仿真信号发生器,虚拟低通滤波器.虚拟实验室的建立弥补了传统实验室的不足,使实验的设计更加灵活,并且紧跟当前科技发展的趋势,顺应了实验教学的改革方向.     

基于双单片机的多功能虚拟实验平台设计

针对当前单片机电子实验室设备过多、集成性和扩展性差的问题设计了由函数信号发生器和虚拟示波器组成的基于双单片机的多功能虚拟实验平台。函数信号发生器采用DDS技术和单片机结合的方法设计了一个信号频率和幅度可以预置且具有很好频率稳定度的函数发生器；虚拟示波器的设计采用单片机和FPGA结合的技术，硬件系统简单可靠、体积小，上位机采用LABWINDOWS结合VC＋＋的技术设计。整个虚拟实验平台在单片机教学改革中使用效果良好     

基于LabVIEW的以太网DDS信号发生器设计

将数字直接频率合成技术(DDS)同虚拟仪器技术结合可有效解决传统信号发生器体积大、携带不便、通信接口少、不具备网络功能的缺陷,以及一般虚拟信号发生器生成高频信号困难的问题.为此,利用LabVIEW虚拟仪器软件设计上位机控制软件平台,利用DDS器件构建信号发生硬件平台.借助以太网将软硬件平台连接起来共同构成以太网DDS信号发生器,并且以具体实例详细讨论了该信号发生器软硬件平台的设计.     

基于LabVIEW虚拟信号发生器的设计与实现

设计和实现了一种基于LabVIEW的虚拟信号发生器,它利用基于LabVIEW编写的程序,根据输入参数生成虚拟信号,利用基于USB接口的MSP-010501数据采集卡把虚拟信号转换为实际信号输出.虚拟信号发生器的主要功能如下:可产生正弦波、方波、三角波、锯齿波等基本波形;可根据公式输入来产生波形;可向任意信号添加噪声.此虚拟信号发生器具有价格便宜、容易开发、可维护性好等优点.     

虚拟仪器实验室的设计

介绍了虚拟仪器实验室的组成,提出了虚拟仪器实验室的设计方案,设计了虚拟仪器实验室的硬件系统与软件系统,其中包括虚拟信号发生器、虚拟数字示波器、虚拟频谱分析仪及虚拟数字滤波器等仪器的设计,并利用设计好的虚拟仪器实验室进行了放大电路的实验,结果证明此虚拟仪器实验室具有良好的实验效果,值得广泛推广.     

基于LabVIEW的网络虚拟实验室的设计和实现

运用模块化的设计思想,对基于LabVIEW的网络虚拟实验室进行了设计.实现了虚拟示波器、虚拟信号发生器等虚拟实验,将虚拟实验作为子VI设计了一个虚拟实验平台,并对虚拟实验平台进行网络化,使网络虚拟实验能真正打破时间和空间的局限,更好的服务于教学与科研工作.     

基于LabVIEW的电工电子虚拟仪器设计

虚拟仪器是以计算机网络为基础,依据使用者的需求对仪器进行升级与改造,利用软件来完成对虚拟控制界面的布置和模拟相对应硬件设备的综合计算机系统。使用者可以通过输入设备(键盘、鼠标、触摸屏)来操控虚拟仪器面板,达到模拟使用真实仪器的目的。以LabVIEW软件为基础,针对电工电子实验中常用的虚拟示波器、虚拟信号发生器进行设计,分析设计了其工作的原理、设计流程、仪器面板、仪器各模块程序框图。     

基于LabVIEW的虚拟示波器设计及应用

以虚拟双通道示波器设计为例,介绍了基于LabVIEW 7 Express和PCI-6024E数据采集卡的虚拟仪器设计过程,并对虚拟函数发生器送出的信号进行采集和频谱分析.实验证明,虚拟示波器实现了传统示波器的基本功能.通过软件修改,开发出了不同的虚拟仪器,实现了一卡多用,增强了系统的灵活性.将虚拟仪器技术与网络技术结合进行远程数据采集,充分发挥了虚拟仪器的优势,最大限度地实现了硬件资源共享.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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