基于IEC1131-3可编程序控制器离线调试软件包的实现

简单介绍了可编程序控制器的编程语言国际标准IEC1131-3,详细阐述了运用VC6.0实现可编程序控制器离线调试软件包的方法,其中包括梯形图实现,指令语言实现及其相互间的转换,SFC实现的方法以及如何实现PLC程序离线调试.     

基于PLC的步进电机控制

介绍了基于OMRON公司可编程序控制器的步进电机控制系统设计,给出了可编程序控制器控制步进电机电气控制系统的硬件组成和软件设计,包括可编程序控制器输入输出接线图、梯形图程序设计和步进电机的驱动电路及可编程序控制器编程软件实现脉冲分配器功能的方法。提出了一种基于PLC的四相步进电机控制的方法,介绍了控制系统的设计方案及其软硬件的实现方法。实现对四相步进电机的启动,停止控制、正反转控制。提出设计总体方案,阐述了驱动电路。方法简单易行,编程容易,可靠性高。     

可编程序控制器在剃齿机床改造中的应用

可编程序控制器是实现工业企业自动化的关键技术,本文对可编程序控制器应用于机床进行了详细的研究.用可编程序控制器来进行生产设备的技术改造,将有利于加快新产品的开发和促进老产品的更新,有利于提高产品质量,有利于大幅度地提高劳动生产率,有利于降低产品成品和增加利润.     

可编程序控制器顺序控制程序编程的研究

虽然简单的顺序控制程序用传统的继电器—接触器控制系统也能实现,但是与可编程序控制器比较起来有很多缺点,在现代工业控制中,用可编程序控制器编写顺控程序是一件省时、省力的工作。本文从应用实例出发,研究了可编程序控制器中可以用来编写顺控程序的方法,并做了一些对比总结。     

可编程序控制器在变频调速系统中的应用

介绍了可编程序控制器控制变频器的方法及硬件连接，变频器参数的设定，可编程序控制器梯形图程序设计。可编程序控制器与变频器结合是一种理想的控制方案，有推广应用价值。     

浅谈可编程序控制器系统供电设计

针对可编程序控制器应用中常受到电网冲击,直接影响控制系统的精度和可靠性,提出了系统供电设计方案。分析可编程序控制器对供电系统的要求,给出了供电系统硬件、软件设计方法。实验证明系统供电电源设计对可编程序控制器抗干扰性具有较大的使用价值。     

工业微机与PLC的通信

主要阐述工业微机与可编程序控制器之间的通信特点及其实现方案。     

可编程序控制器课程建设初探——综合电工实验台功能的扩展

该文介绍可编程序控制器的应用、课程开设的设想及在综合电工实验台的基础上,增设可编程序控制器实验的研究。     

可编程控制器对风机的控制

通过对可编程序控制器在高压离心风机上应用的关键技术研究 ,设计了风机起动和运行的可编程序控制器硬件和软件。     

浅论可编程序控制器直接控制步进电机系统

介绍了运用可编程序控制器直接控制步进电机系统的软硬件组成,阐述了可编程序控制器直接控制步进电机技术在发动机台架试验测控系统中的应用。     

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.     

An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

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.     

大肠杆菌pheA与tyrB基因的克隆与串联表达

为探讨用基因工程的手段改良苯丙氨酸的发酵菌株，采用聚合酶链反应（ＰＣＲ）的方法，从大肠杆菌总ＤＮＡ中克隆得到了编码苯丙氨酸合成途中的两个关键酶基因－即分枝酸变位酶（ＣＭ）／预苯酸脱水酶（ＰＤ）基因ｐｈｅＡ与苯丙氨酸转氨酶（ＰＡＴ）基因ｔｙｒＢ，在大肠杆菌中进行了这两个基因的单个和串联表达。ｐｈｅＡ和ｔｙｒＢ基因分别都能在λ噬菌体的ＰＲ启动子之后得到较大量的表达，在ＳＤＳ－ＰＡＧＥ上出现清晰的条带，     

四川溲疏属的分类研究 （Ⅱ）：种的简介及新分类群

介绍了四川溲疏属植物20种,5变种及1栽培变型,每种均有文献考证、学名订正、特征集要及产地和生境,新分类群D.leiboeneie P.He et L.C.Hu, D.piloea var.longiloba P.He et L.C.Hu,D.jinyangensis P.He eL L.C.Hu及D.longifolia var.deneitomentosa P.He et L.C.Hu均有详细拉丁文描述并附模式标本照片,还记录了两个四川省新分布种:D.bodiaieri Rehd.,D.rehderiana C.K.Schn.,对伞花亚组Subsect Cymosae Rehd.中建立的新系(Ser.Multiradiatae P.He,Ser.Pauciradiatae P.He)作了拉丁文补充描述。     

在Java技术之Servlet中实现文件的上载功能

Java这门编程语言以及相关技术的使用得到快速的增长;现在大约有700多万台计算机正在运行Java应用程序,有近100万的Java开发人员,世界上所有的企业中,几乎有一半正在开发 Java应用程序。Java成功的理由是很自然的,Java是真正与平台无关的,它是适合于任何操作系统的一种通用的编程语言;Java是完全面向对象的,这在软件工程和组件技术方面有了很大的进步;Java的安全模型是成熟的,这与其他容易感染病毒的模型系统形成了鲜明的对比。     

中国阳蝇属六异名记述(双翅目:蝇科)

阳蝇属是蝇科最大的属之一,迄今全世界已知阳蝇属约666种,分布于世界各大地理区。近年来对阳蝇属种团和类群的研究,发现在我国阳蝇属中存在一些异名问题。在我国阳蝇属已知226种中,发现小兴安阳蝇(Helina xiaoxinganna Xue,2001)、茂县阳蝇(Helina maoxianica Feng,2008)、后曲阳蝇(Helina postiflexa Xue,Feng& Tong,2008)、团宝山阳蝇(Helina tuanbaoshanica Feng,2007)、兴凯阳蝇(Helina xingkaihuica Feng& Ye,2007)和错那阳蝇(Helinacuonaica Feng&Xu,2008)等6个种存在同物异名问题,并根据模式标本及原始文献,指出了同物异名的理由,明确给予了订正。     

采用有限差分方法求解固体弹性应力场(英文)

为了采用全有限差分方法进行涡轮气热弹耦合计算,研究了固体弹性应力场计算的物理模型,给出了任意曲线坐标系下的控制方程.同时研究了定常问题的有限差分求解方法和边界条件的给定,编制了定常问题的应力场求解程序;并通过对具有解析解的受集中载荷的悬臂梁和一端受径向集中力的曲梁进行数值计算来验证该固体弹性应力场的求解方法.结果表明,边界条件的二阶精度处理的格式所得结果与解析解数据吻合得较好,而一阶精度格式结果与解析解有较大的误差.     

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.     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to