引入光硬件限幅器的光PPM-CDMA通信系统

提出了一种引入光硬件限幅器的光PPM-CDMA(脉冲位置调制-码分多址)通信系统方案,即在接收机相关器之前引入一个光硬件限幅器,以便更好地减少多用户干扰.在系统中存在多用户干扰及接收机散粒噪声的情况下,推导出该系统误码率上限,并对该系统特性与无光硬件限幅器的光PPM-CDMA通信系统特性作了比较.分析结果表明,引入光硬件限幅器系统的误码特性得到明显的改善.     

单片机与微型打印机的接口硬件设计

本文设计了以AT89S52为核心的微型打印机接口硬件,介绍了AT89S52单片机接口转换电路及微打的串行通信方法,此方法也可应用于其它类型的微型打印机及串行通信场合。系统可以无须通过微机直接打印,具有硬件构成简单、成本低、通信可靠的特点。     

单片机与微型打印机的接口硬件设计

本文设计了以AT89S52为核心的微型打印机接口硬件,介绍了AT89S52单片机接口转换电路及微打的串行通信方法,此方法也可应用于其它类型的微型打印机及串行通信场合。系统可以无须通过微机直接打印,具有硬件构成简单、成本低、通信可靠的特点。     

基于USB接口的DSP通信系统设计

本文提出了一个基于USB接口的DSP通信系统,介绍了系统的软、硬件构成,及系统的工作流程。     

面向自重构系统的软硬件协同透明编程模型

可重构计算系统设计中把计算密集的代码用硬件加速器实现以提高系统性能已经成为一种常用的方法。但是在包含硬件加速器的系统中,程序员要了解硬件加速器的实现细节,控制硬件加速器的配置、软件和硬件模块之间的通信,这种不透明的编程方式影响了系统开发效率。本文提出了一个对程序员透明的软硬件协同编程模型,程序员可以像调用一个软件函数一样去使用一个硬件加速器,而把硬件加速器的配置、软硬件通信等操作交给操作系统和辅助硬件控制器实现。同时,该编程模型采用自重构技术即由嵌入式处理器控制完成动态重构,可支持动态调用多个硬件函数,使得多个硬件加速器可以分时复用硬件资源,从而提高系统资源利用率。     

两级分布式多微机监控与管理系统的通信技术

提出了一个在管理级系统机与监控级多微机之间实现长距离、多通路通信的富有特色的通信系统方案。讨论了通信链路的硬件构成及原理，分析了通信过程，并给出了通信协议和通信软件流程图。本通信系统可用于各种工业过程的控制与管理系统中。     

变电站监测、控制、保护系统的通讯单元

介绍了在变电站综合自动化中采用ＲＳ－４８５串行通信标准构成主从分布式通信系统的硬件实现和软件实现．本通信系统由于采用了ＲＳ－４８５串行接口通信标准（半双工），具有节省信号线及高速、远距离传输信息的优点．     

局矿间安全监测及管理计算机网络的研究

本文采用计算机通信手段解决了局矿间通风调度通信管理问题。在对系统结构设计的基础上.研制了计算机通风调度通信系统中的硬件及软件.复用电话线进行计算机通信,解决了系统的线路投资问题。通过对通信处理机的研制实现了系统的通信不影响监测主机的正常工作.     

基于TMS320VC5509和TLV320AIC23的语音通信系统设计

为了提高语音通信中语音信号的质量和处理速度,设计了一种基于DSP芯片TMS320VC5509和语音编解码芯片TLV320AIC23的语音通信系统,分析了该系统的总体方案设计、硬件接口电路设计、工作参数配置和语音通信的工作流程.     

水利信息系统运行维护经费测算项目及应用

1测算的内容水利信息系统运行维护测算项目主要包括:硬件系统运行维护、软件系统运行维护、基础环境运行维护。(1)硬件系统运行维护。硬件系统运行维护包括:通信硬件系统运行维护、计算机网络硬件运行维护、视频会议及视频监控系统设备运行维护。(2)软件系统运行维护。     

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.     

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.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

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-