光伏控制系统中冗余技术的研究与应用

本文主要针对双机冗余的故障检测及自动判决等关键技术进行研究,提出了一种双DSP冗余结构的光伏控制器的设计方案。以TI公司的控制芯片TMS320F2812为核心,研究并实现了双DSP冗余结构的光伏控制系统,双DSP分担处理信号并且互为备份,通过检测各自的关键信号来判断故障状态,并能迅速通知备份DSP做出切换;解决了传统冷备份系统冗余切换速度慢、数据采样频率低的缺点,减少了系统的故障时间,提高了系统的可靠性与稳定性。实验结果表明该方案可行且有效。     

一种物理链路检测电路设计及仿真模型实现方法

检测电路用于动态检测多节点系统中节点间物理传输链路连接故障,以便系统采用链路降宽、冗余设计等手段提高系统可靠性。其仿真模型是指在系统级功能仿真验证阶段建立合理的检测电路软件模型,以保证设计验证的顺利进展,同时也为研制工作节省时间开销和设计成本。本文介绍了一种物理链路检测电路的设计方法,并且实现了其软件仿真模型的设计方法。     

基于随机Petri网的冗余备份系统可信赖性研究

可信赖性的度量能客观反映冗余备份系统的可信性,是评价冗余系统服务能力的主要准则.随机Petri网(SPN)对系统的并发性、异步性和不确定性具有很强的动态分析能力,特别适合系统建模和可信赖性分析.讨论了冗余备份系统的概念及其随机Petri网描述,采用SPN对冗余备份系统进行建模和分析,在模型分析的基础上给出冗余备份系统的可靠性、可用性、可生存性、平均故障间隔时间等各种可信赖性重要指标.实例研究表明备份部件所处不同的状态会导致冗余备份系统具有不同的可用性.     

通讯设备的可测试性与可靠性分析

为了满足通讯设备、网络设备等高可靠度和高可用度的要求,这些设备的重要组成单元都会采用冗余备份措施,借鉴失效模型故障分析(FMEA)的思想,本文提出了一种新的关于故障检测率的定义方法,并在此基础上提出了一种提高冗余备份单元的故障检测率的设计方法。     

新型电子设备的故障自动检测

该文根据检测、估计理论以及数字信息处理技术,论述了新型电子设备故障自动检测系统的理论基础;提出了以微处理器为核心的自动数据采集、故障自动诊断系统以及具体硬软件电路的实现.实现该系统对于新型电子设备朝着自动化,智能化方向发展,提高新型电子设备的可靠性具有一定的实用价值.     

基于群集ORACLE自动备份设计与实现

网络应用广泛,对于数据及应用进行集中式管理,要求信息存储高可靠性日趋强烈.利用群集服务和磁盘阵列构建双机互备,使ORACLE自动备份系统运行在其上,来提高数据存储的可用性和可靠性.具体针对在群集系统上实现ORACLE自动备份,阐述此方案总体设计和实现过程的技术要点,达到重要数据冗余备份.     

基于群集ORACLE自动备份设计与实现

网络应用广泛,对于数据及应用进行集中式管理,要求信息存储高可靠性日趋强烈.利用群集服务和磁盘阵列构建双机互备,使ORACLE自动备份系统运行在其上,来提高数据存储的可用性和可靠性.具体针对在群集系统上实现ORACLE自动备份,阐述此方案总体设计和实现过程的技术要点,达到重要数据冗余备份.     

BDF技术在电力通信网主备链路切换中的应用研究

在电力通信系统中,为了保障网络的可靠性,通常采用双设备双链路的进行冗余备份,以便于在设备或链路发生故障的时候能够切换保持网络稳定。本文针对电力系统中常用到的静态路由结合VRRP主备切换收敛时间慢、无法检测远端链路状态的不足,采用BFD检测技术辅助静态路由协议进行远端链路状态检测,解决了静态路由无法检测远端链路故障而导致主备链路无法切换的问题,同时大大提高了主备链路的切换的收敛时间。     

搅拌设备控制系统的输入信号预处理电路设计

为了提高沥青混凝土搅拌设备计算机控制系统的可靠性，针对其工作环境对输入信号预处理电路的特殊要求，通过比较的方法，论述了温度检测和配料称量等模拟信号及开关量输入信号处理电路设计的依据，并设计了相应的电路。针对变频器输出频率显示信号中的高频噪声，设计了相应的噪声消除电路，给出了进一步提高系统抗干扰能力的措施。将设计的电路应用于LB2000和LB3000型沥青混凝土搅拌设备计算机控制系统，进行了测试。测试结果表明：输出信号稳定，且消除了高频干扰，提高了系统的可靠性和抗干扰能力。     

基于STC89C52的自动路灯控制系统设计

设计采用STC89C52RC单片机为核心包括LCD12864显示电路、路灯驱动电路（4路独立工作）、故障检测电路、物体通过检测电路、光照采集电路、无线射频模块、555时基电路和电源模块。设计通过光照检测电路与物体通过检测电路可以实现在高照度下和无车辆或行人通过时自动关闭路灯达到节能目的,故障检测电路和无线射频模块相结合可以实现及时有效的维修维护响应,提高公共设施服务质量。     

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