共查询到20条相似文献，搜索用时 62 毫秒
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张怀广 《濮阳职业技术学院学报》2009,22(6):134-135
单片机系统运行时常存在各种干扰因素,克服这些干扰因素的方法主要分为硬件抗干扰扣软件抗干扰。本文介绍单片机系统中软件“看门狗”技术和故障处理。 相似文献
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针对PLC系统现场应用时因干扰而发生故障的现象,分析了PLC系统现场应用时的常见的干扰来源和干扰的途径,提出了消除或减少干扰的办法和保证PLC系统稳定运行的对策. 相似文献
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程敏珍 《福建工程学院学报》2007,5(4):340-343
收集建筑消防系统实际运行资料,分析影响建筑消防系统正常运行的因素;通过建立故障树和数学模型,利用故障树分析法对系统运行过程可能产生的故障进行定性和定量分析,确定系统可靠度和各故障因素的概率重要度,据此判定系统中事故频发的环节,为改善系统运行和提高系统的可靠性能提供理论依据. 相似文献
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文章主要对农村10kV配电网线路中常见故障以及应对故障的方法进行分析和研究。由于农网线路具有负荷分散、供电半径大的特点,在面对恶劣天气、外力等因素干扰时,易导致线路事故频发,降低线路供电运行的可靠性和稳定性。在10kV线路中最常见的故障是单相接地故障和相间短路故障。为了有效地应对线路中常见的两种故障,提高线路的自动化水平,文章基于农村电网的特性,对比了故障指示器和网络馈线终端单元（Feeder Terminal Unit,FTU）在农网中的经济适用性,并详细分析故障指示器系统在10kV配电网中的故障监测及定位的作用。结果表明：故障指示器系统在10kV线路中的引入,可实时监测线路负荷变化,预防线路故障,优化一次结构并及时消除隐患,有效提高线路自动化水平。在资金投入方面,相对其他故障定位系统其投入最低,经济化程度最好,为后期农村电网的规划设计和运行维护提供了参考。 相似文献
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GSM通信系统受到上行干扰会增加系统的掉话率,同时基站覆盖范围减少,通话质量和网络性能指标受到严重影响,可能导致通话出现断续、杂音等,影响用户通信质量。引起上行干扰的主要原因有:基站设备中硬件故障,内部干扰,外部干扰等。上行干扰的来源大都是由于直放站故障、外部干扰器(屏蔽器)干扰、不同网络间干扰、民用设备干扰等原因引起。通过一次通信故障处理案例,阐述了天线隐性故障导致的上行干扰情况。 相似文献
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针对存在未知时变惯量不确定性、外部干扰力矩和执行机构衰退故障的非刚体航天器系统,研究了非刚体航天器自适应优化容错控制问题。首先,为了根据误差变量优化控制增益,设计一种动态增益调整函数实时优化控制增益;然后,基于非线性鲁棒控制方法、动态增益函数调整方法、自适应方法、容错控制理论与参数估计方法,提出一种新颖的自适应优化姿态跟踪容错控制器。所设计的控制器克服了执行器故障、惯量不确定性以及外界干扰的影响,保证航天器姿态及角速度能够跟踪时变的参考轨迹,实现跟踪误差系统最终一致有界稳定;最后,数字仿真结果验证了所提出方法的有效性,而且与已有控制方法相比,该方法具有更高的控制精度和稳定性。 相似文献
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为了保障列车站间运行的安全性、可靠性,以故障-安全控制策略为基础,研究了列车站间运行过程中的协同运行与交互控制机制,建立了系统通信模型,提出了一种可行的列车运行控制系统通信控制策略。基于列车运行控制双模-冗余热备的系统架构,分析了列车站间运行过程中的状态控制策略,采用马尔柯夫过程研究了系统的可靠性和安全性。根据设定的参数,进行了系统仿真。仿真结果表明系统具有良好的可靠性与安全性。 相似文献
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谢宏祥 《中国教育发展研究杂志》2009,6(7):91-93
近年来,单片机在工业自动化、生产过程控制、智能化仪表等领域的应用越来越深入和广泛,有效地提高了生产效率,改善了工作条件,大大提高了控制质量与经济效益。但是,测控系统的工作环境往往是比较恶劣和复杂的,因此微机测控系统必须长期稳定、可靠地运行,否则将导致控制误差加大,严重时会使系统失灵,甚至造成巨大的损失。因此提高微机系统的可靠性、安全性,成为人们目益关心的问题。单片机抗干扰技术的研究,就是在这种需求下产生的。 相似文献
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《佳木斯教育学院学报》2018,(4)
在应用PLC期间也会存在信号干扰,并且存在多样化的干扰源,通过某些方式对PLC控制系统产生不同程度的干扰情况。为了确保PLC系统能够安全稳定运行,需要对其进行抗干扰处理,主要通过"应用屏蔽措施"、"正确的接地和搭接"、"合理的选择PLC系统中的设备"、"采用滤波技术"和"正确的使用电缆敷设"几个方面解决PLC控制系统的干扰问题。 相似文献
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《海外英语》2007,(5):10-11
Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help? 相似文献
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罗艳萍 《读与写:教育教学刊》2008,5(6)
The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity. 相似文献
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《海外英语》2007,(4):36
There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love. 相似文献
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Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject. 相似文献
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Richard Denner 《海外英语》2007,(4):14-15
Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose. 相似文献
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Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities. 相似文献
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RUZBEHANI Mohsen 《重庆大学学报(英文版)》2004,3(1):20-25
1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec… 相似文献