基于USB的测量仪器控制系统的开发

数据采集是科学研究中一个重要手段,数据有效的采集和精确的计算就成为研究中关键的一环。如今随着USB3．0标准的发布．其传输速率可达到5GB／s,采用USB与虚拟仪器设备进行通信是大势所趋。由于USB的简单易用和通信的稳定性,许多测试系统开发人员已经在仪器I／O中采用USB的连接方式。本文简要地介绍了USB技术的最新发展,SCPI命令的语法结构及使用方法及Agilent34410A万用表的技术特性,采用VISA—COM技术实现对Agilent34410A数字万用表的远程控制,结果表明开发出来的程序能满足自动控制系统的需求。     

试述GPIB总线虚拟仪器的系统设计

文章结合作者实际工作,简要介绍了GPIB技术及GPIB总线虚拟仪器,在此基础上,结合案例阐述了实验软件编程的操作过程,得出结论：通过编程把适当的GPIB命令通过两个Ⅵ发送给仪器或者接收仪器返回信息。最终确定为使用GPIB总线的虚拟仪器在使用中比较方便。     

用VB实现PC机与GPIB通讯卡的通讯

主要研究波形测试及分析系统数据传递问题,测量模块采用GPIB总线标准,模块与计算机间的通讯用VB编程实现。     

数字示波表SCPI程控命令解析器设计

SCPI是测试测量仪器程控命令的重要标准,被广泛应用于各种程控测试测量仪器中。针对数字示波表的SCPI程控命令,研究并设计了一种SCPI命令解析器,采用Xml文档来描述SCPI命令树,最大程度简化了创建命令树的过程。设计的解析器具有高度的可扩展性和通用性,已应用于数字示波表中,验证了此方案的可行性。     

基于GPIB接口数据采集系统的设计

提出了一种基于CPIB接口的数据采集系统的设计和实现方案,并详细介绍了该数据采集系统的硬件结构、接口电路和软件设计.GPIB接口应用到数据采集系统中,提高了数据采集系统的可程控性,增强了系统的抗干扰能力和数据传输的可靠性.同时,基于GPIB接口的数据采集系统也大大降低组建自动测试系统的成本,提高了测试人员的工作效率.     

多功能电参量测试仪的LXI总线接口设计

针对基于单片机的多功能电参量测试仪的LAN etension for instrument(LXI)总线接口设计,给出了一种线路简单、成本低并具有抗电磁干扰特性的硬件接口设计方案;根据国际程控仪器标准命令(SCPI)的语法结构设计了测试仪器的控制命令集,采用孩子兄弟表示法创建了SCPI命令的链式二叉树的存储结构;并采用非递归遍历的算法完成了SCPI命令树的解析,实现了PC与测试仪的通信。实验结果证明,该LXI总线接口硬件电磁兼容性能与软件功能均达到了实际应用的要求。     

基于声卡的RLC电路稳态特性(相频部分)采集系统

介绍了基于声卡的RLC电路稳态特性(相频部分)采集系统.系统以Delphi作为开发平台,声卡为数据采集卡,调用Windows标准API函数编程而成.主要包括数据实时采集、波形实时显示、数据分析处理、结果显示、采集数据保存和数据回放.实验结果表明系统是成功的.     

GDS-820数字存储示波器控制软件的开发

针对应用数字存储示波器采集超声引线键合机换能器驱动信号时,遇到的大量数据难以浏览、难以方便传输到计算机中的问题,在研究了示波器通信协议(SCPI协议)基础上,提出了一种数据拼装的方法.根据该方法,在VB6.0的软件开发平台上,采用Cwserial控件,对计算机串口进行编程,开发了示波器控制软件,扩展了其数据通信的功能.实验结果表明:该方法可完整、方便、准确地将示波器中存储的数据传输到计算机中,解决了研究中所遇到的数据采集问题,提高了换能器系统驱动信号数据采集的速度和效率,为后续的超声引线键合机理的研究提供了便利.     

小型自来水厂数据采集与监测系统的设计

目的 设计小型自来水厂的数据采集和监测系统.方法 采用单片机系统采集数据,使用VC++软件编程,实现图形界面的设计.结果 实现了对数据的实时采集,并通过计算机进行监测.结论 设计简单,已应用于自来水厂中.     

基于虚拟仪器的混频生物阻抗测量系统

为获得同一时刻、不同频率下的生物阻抗信息,设计了基于虚拟仪器的混频生物阻抗测量系统.该系统硬件平台由自主开发的信号源模块和信号调理模块以及NI公司的PCI-6111板卡组成.对混频激励下阻抗信息的提取方法进行了研究,提出了基于虚参考点的数据采集方法,利用LabVIEW实现数据的采集、分析处理、显示和存储等,大大提高了开发效率.通过与Agilent4294A阻抗分析仪进行比对,证明该系统具有较高的测量精度和准确性.     

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

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