串行通讯在机器人内窥镜主动避障监控系统中的应用

该文结合内窥镜机器人主动避障控制系统的应用,介绍了VB的通讯控件MSComm的属性以及上、下位机串行通讯的通讯接口和通讯协议．详细分析了在VB环境下,通过PC与单片机的串行通讯,以监控机器人内窥镜在介人人体结肠过程中主动避障的实现方法和程序设计．     

RS-485总线在温度测量系统中的应用

本文论述了温度测量系统中数据采集单元与上位机数据通讯的问题,通过一整套通讯协议使上位机由被动接收变为主动管理保证了数据通讯的可靠性.介绍了上位机通过控件实现串行通讯的方法和单片机实现485通讯的方法.讨论了波特率设置问题对串行通讯的影响.     

在VB5.0平台下实现PC机与单片机的串行通讯

主要介绍了如何使用VB5 .0中的一个ActiveX控件来实现Windows下PC机与单片机之间的串行通讯 ,详细地讲述了单片机的程序设计和VB5 .0中串行通讯控件的使用方法。程序中通过调用通讯控件的各属性隐含了串行口的硬件特性。适当变化上述模块 ,就可以根据具体的任务在PC机上用VB设计出界面和后台数据库 ,与单片机或其它系统进行串口通讯     

Windows环境下PC机与PC104的串行通讯控制

介绍了Win98环境下利用VB的通讯控件(MSComm控件),实现PC机与PC104的串行通讯方法。详细描述了PC机与PC104之间通讯涉及的通讯端口初始化、命令发送、数据接受以及数据效验等及编程技巧;并给出PC机与PC104之间的串行通讯源程序。     

一种工业控制串行通信网络

论述了一种用工业 PC,STD-PC 工控机异步串行通信口组成串行通信网络的方案。主要讨论了网络中信息包的组成,主从机的通信协议及信息包接收、发送的程序设计。     

基于RS-422总线的单片机多机通讯接口的设计与实现

本文阐述了主从式多机通讯的原理,提出了一种基于RS-422串行通信接口的方案和软件设计方法．针对计算机与8051系列单片机串行口的通讯特点,设置计算机中通讯控制寄存器,使计算机满足单片机多机通讯的格式,实现了计算机和单片机的多机通讯．该方法已在实际应用中被广泛采用,并可推广应用于其他系统,对其他系统的硬件电路设计及程序设计具有一定的参考价值．     

低压电力集中抄表系统在供电部门中的应用

本文提供了一种经济、可靠的小区集中抄表系统的解决方案:即基于工厂模式集中不同厂商的集中抄表系统的通信协议,并利用VB6.0 ActiveX控件中的MSComm串口通讯控件,实现了上位机与与集中器间的串行通讯,抄读的数据通过集中器传送到后台管理服务器机中,对数据进行相应的处理和统计分析。     

主从分布式系统主单片机串行通讯管理的新方法

介绍在复杂的主从分布式系统中提高主机串行通讯与背景程序实时性的一种方法.该方法采用接力棒来管理串行通讯,使之与其他事件达到并行运行的效果.     

利用高级语言实现PC机与多单片机的通讯

以PS1016单片机为例,介绍了PC机与单片机之间的串行通讯,技术,研究结果表明：在Windows98下利用VB的串行通讯控件可实现PC机与多单片机的通讯,采用定时器控件大大加快了自动化进程,并可克服以往多握手协议造成的通讯速度缓慢。     

单片机与PC机串行通讯的实现

PC机具有处理速度快,存储量大,良好的用户界面.而单片机具控制方便,接口简单等特点.因此PC机与单片机相结合在工业监控、数据采集和实时控制系统广泛应用.本文介绍了AT89C52单片机与PC机之间串行通讯实现,包括硬件结构及软件设计.单片机部分由汇编语言实现,PC机部分分别介绍了用VB语言的MSComm控件及调用W indows API函数来实现通讯.     

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.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

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.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

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