色谱仪控制系统的Modbus从站设计与实现

在色谱仪系统开发中,为了解决ARM7与mcgsTpc触摸屏之间的通讯,提高ARM7处理器与触摸屏之间通讯的稳定性和可靠性,采用了基于Modbus RTU通讯协议的串口通讯的设计方法。在S3C44BOX微处理器上,以μC/OS-II实时操作系统为软件平台,详细分析了Modbus从站的设计和实现过程,解决了使用Modbus RTU通讯协议的读或写寄存器功能传输浮点数的问题。完成Modbus从站应用通讯程序的设计。实现了ARM7与触摸屏的通讯。经测试验证通讯稳定可靠。     

嵌入式电力数据采集系统的设计与实现

针对嵌入式在电力系统中的应用需求,设计了一种基于ARM微处理器的电力数据采集系统;系统以S3C44B0X作为控制核心,使用SP3539芯片扩展多个串口,实现了对多条RS-485总线上电力数据的采集、显示、存储等功能,并基于TCP/IP协议将数据传送至远程主控中心.变电所的实际运行效果表明,该系统具有较高的稳定性和可扩展性,能满足变电所电力数据采集的要求,具有良好的实用价值.     

浅谈Modbus协议及其应用

Modbus协议是工业现场总线的一种通用语言,它已经成为一通用工业标准,通过它不同厂商生产的控制设备可以连成工业网络,进行集中监控.此协议定义了一个控制器能认识使用的消息结构.此协议支持传统的RS-232、RS-422、RS-485和以太网设备.PLC、DCS、智能仪表等都在使用Modbus协议作为他们之间的通讯标准.该文就应用方面做一些介绍.     

嵌入式实时操作系统下TCP/IP协议栈的设计

在以S3C44B0X为MCU的基础上,选择了免费、源码公开的μC/OS-Ⅱ实时操作系统作为开发的软件平台。研究了一种适用于嵌入式系统的TCP/IP协议栈LwIP,并将其移植到嵌入式系统中。在此基础上设计相关网卡驱动程序,经测试程序验证,LwIP协议栈在基于S3C44BOX的硬件平台和μC/OS-Ⅱ软件平台下运行良好,实现了嵌入式系统的网络化。     

基于嵌入式系统的家庭病床远程医疗服务系统

提出了一个由ARM系列微处理器S3C44B0X与MC35 GPRS模块构成的家庭病床远程医疗系统.介绍了S3C44B0X及MC35的性能特点、系统的组成原理,以及主要外围接口电路的设计和软件设计架构,给出了GPRS模块的软件配置方法.经过实验测试表明,系统在实际中取得了良好的效果.     

基于CAN总线的云台镜头解码器设计

针对闭路电视监控系统中云台镜头解码器的通讯通常采用RS-485协议,而控制器局域网络(CAN)是一种能有效支持分布式控制和实时控制的串行通讯网络,具有高性能、高可靠性的特点.以P87C591单片机为控制器,设计基于CAN总线的解码器系统,并给出硬件电路和软件编程,开发了CAN应用层通讯协议,实现了控制数据的快捷传输.     

基于ARM的TFTP实验的开发

本文基于ARM7和TCP/IP协议相关理论基础,设计了S3C44B0X芯片及CS8900的硬件电路,并设计了应用层、传输层、网际层、网络接口层的软件实现,最终实现了客户端基本的TFTP功能。     

基于S3C44B0X处理器的μC/OS-Ⅱ的移植方法研究

主要研究了嵌入式操作系统μC/OS-Ⅱ在ARM7上的移植方法。首先,分析了μC/OS-Ⅱ的软硬件体系结构。然后,在基于ARM7架构的Samsung S3C44B0X硬件平台上,成功地将μC/OS-Ⅱ移植到S3C44B0X处理器上。详细说明了μC/OS-Ⅱ的移植过程,给出了移植的具体方法和步骤。设计的移植方法不但使系统速度快、性能稳定,而且操作简单,具有很高的实用价值。     

S3C44B0X平台上嵌入式操作系统μC/OS-Ⅱ的移植

根据嵌入式处理器S3C44B0X和嵌入式实时操作系统μC/OS-Ⅱ的特点,通过实现三个源代码文件将μC/OS-Ⅱ移植到S3C44B0X上,并给出详细的移植测试方案,具有重要的实用参考价值。构成的嵌入式系统应用开发平台和专门设计的中断系统有机结合起来,可有效提高该系统的实时性和执行效率,简化嵌入式应用软件的开发流程。     

基于Modbus的电磁流量计通讯在污水计量中的应用研究

本文深入分析了基于Modbus协议的电磁流量计通讯在污水计量中的应用,通过RS-485串口连接,进行相关的流量信息的读取,从而切实可靠的保证了数据稳定性、可靠性和精确性。     

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.     

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