共查询到20条相似文献，搜索用时 62 毫秒
1.
设计了一种负载可变的高频电刀老化试验装置,采用多个功率为100 W的大功率电阻进行串并联构成电阻网络,用STM32F407单片机驱动继电器控制电阻网络中电阻的通断,改变负载的阻值,实现老化试验装置负载可变的目标,解决了企业的技术难题。 相似文献
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摘用MATLAB研究了振动系统在与速度平方成正比的阻尼作用下的运动性质,采用平均法求出了平方阻尼情况下振动微分方程的近似解析解,讨论了解析解的使用条件并与数值解进行了比较．发现平方阻尼下,振动系统进行周期性的非指数型衰减振动,在一定条件下,采用近似解析式描写这种运动,有很高的精度． 相似文献
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为帮助学生理解冲击电压发生器的原理,掌握操作方法和测量方法,设计了100 kV/1 kJ可移动小型化冲击电压发生器实验教学装置.该装置的波头、波尾电阻采用弹簧压接拔插方式,具备模拟和数字双显示功能,装置配有弱阻尼电容分压器和纯电阻分压器,本体球距可自动调节,有自动接地和警铃提醒.经公式计算、仿真模拟、实验验证,该装置的... 相似文献
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自动化生产中,自动检测设备的使用越来越广泛,为保证检测精度,这类设备都需要控制气动和电动振动对检测的干扰和影响．为此本文设计了MRF可控阻尼器及可调振动滑台装置,总结基于MRF力学模型和磁路设计模型,设计MRF阻尼器的经验;基于NI数字化测试系统检测MRF阻尼器控制移动滑台振动的效果．实验结果证实MRF阻尼器能快捷方便地调节阻尼、高精度控制移动滑台的振动,MRF阻尼器振动控制装置具有教学实用价值． 相似文献
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为满足对直流电源试验要求,提出了一种采用滞环控制的恒流电子负载模拟功率负载系统的方法,用该方法研制了恒流电子负载装置.试验结果表明,该恒流电子负载能根据所设定的负载性质自动调节负载电流,满足直流电源的试验要求. 相似文献
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《实验室研究与探索》2016,(3):64-69
设计并实现了一种用于实验研究透平叶片冲蚀成因、冲蚀行为和规律的中高温、低马赫数(Ma0.3)负压风洞实验系统。采用引风机提供负压环境,空气电加热器对气流进行可变温加热,翅片管式换热器对二相流降温,袋式除尘器回收冲蚀颗粒,并使用监控PC机通过DIGATTOT串口服务器进行实验数据采集和试验系统监控。经测试,系统最高温度可达750℃,气固两相流颗粒浓度可调,冲蚀速度可调,可0°~90°任意冲角调节。系统通过了温度、速度稳定性测试以及换热器性能测试。 相似文献
7.
刘正义 《福建工程学院学报》2013,11(3)
截停失控车辆是维持交通秩序时难免要采用的手段.针对目前采用的地钉等截停手段存在操作不便或易损坏车辆的缺点,该研究合理组合钢丝绳、动滑轮、阻尼液压缸等截停手段,设计出能根据要截停的车辆情况进行串联或并联的挡阻装置.经相关理论分析验证,该挡阻装置在合理的挡截距离内可消耗掉失控车辆的动能,实现柔性截停,且可反复使用. 相似文献
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电机拖动实验装置常见故障维修 总被引：1，自引：0，他引：1
介绍了电机拖动实验装置中常见故障的维修,包括三相可调电阻、电枢调节电阻、励磁调节电阻、功率因素表和转速表等,以及它们的处理方法,总结了查找相关故障的正确步骤。 相似文献
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目的:提升纯电动汽车续航能力,减少能量损失,提高能量利用率。方法:通过分析汽车行驶过程中能量损失情况,研究电动汽车分布式线控制动能量回收方案。基于制动强度分配、电池荷电状态以及车速,研究对制动能量回收的影响,分析电压、电阻、转速对电机回收功率的影响,设计能量回收策略,并在分布式线控制动模型的基础上,利用Simulink与CarSim的联合仿真环境进行试验。结果:随着制动强度的增加,优化后的制动系统对能量回收的效果逐渐高于优化前。结论:优化后的分布式线控制动系统回收的能量增加了1.55×105 J,优化后的控制系统能有效地提高了制动能量回收率。 相似文献
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基于大型铁磁材料的磁致伸缩特性是电力设备发生电磁振动的主要因素,提出了一种适用于普通实验室环境的硅钢片磁致伸缩测量系统,设计了能产生外加磁场的螺线管用来激励硅钢片发生形变,运用陶瓷发热片和温度传感器对硅钢片温度进行调节和控制。基于高精度应变电阻片实现对硅钢片形变的测定,通过理论仿真和实验研究,该装置能准确测量饱和状态和不同温度下的磁致伸缩率。为电磁测量实验及电磁振动分析提供了可靠依据。 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
14.
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
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Rajesh Kanoi 《海外英语》2007,(1):52
Today, Sunday morning, I sit thinking and typing at my computer. My thoughts are in my homeland, India and my body is in China. The body is here and mind there for a good reason. Mr. Hu is president and I am resident and both are in each other's countries (what a difference the absence of one small letter makes!). Mr. Hu will return in a few days and I will stay on longer. 相似文献
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正A One day a pig went to the stable(马棚)to see his good friend,an oldhorse,and was going to stay there forthenight.Night came and it was time forsleep.The pig went into the straw heap(稻草堆)and lay comfortably.A longtime passed,but the horse was stillstanding there and did not move.Thepig asked the horse why he did not go tosleep."Standing like this is the begin-ning ofsleeping,"answered the horse. 相似文献
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《今日中学生》2014,(9)
正1.Any fool can count the seeds in an apple.Only God can count all the apples in one seed.2.Happy families are all alike;every unhappy family is unhappy in its own way.3.Memories are the key not to the past,but to the future.4.Sometimes in the dark you see what you want to see.5.There is a great difference between 相似文献
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《重庆大学学报(英文版)》2014,(2)
正Scope and Policy The Journal of Chongqing University-English Edition(JCQU-E)is a peerreviewed journal publishing research articles in multiple disciplines of science and technology,covering civil and environmental engineering,chemical engineering,biotechnology,mechanical and electrical engineering,computer and data processing,mining,metallurgy,materials science,and interdisciplines thereof. 相似文献