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Search Results: 1 - 10 of 304687 matches for " 王锎 "
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基于磁流变阻尼器的双跨轴系PID振动控制研究
郭咏雪,何立东,
- , 2018, DOI: 10.13543/j.bhxbzr.2018.03.010
Abstract: 为了解决双轴串联的旋转机械在临界转速处产生共振问题,搭建了双跨转子实验台,在不改变原有支撑形式的条件下将磁流变阻尼器分别安装在串联的轴1、轴2上,并建立双跨轴系振动的半主动控制系统,采用比例-积分-微分(PID)控制方法,以振幅为反馈参数实时调节阻尼器电流,在线抑制双跨轴系的振动,并在此基础上通过整定PID控制的比例系数K研究其值对振动控制效果的影响。实验结果表明:基于磁流变阻尼器的PID控制系统可以有效控制两个串联轴在临界转速附近的振动;对临界振幅过大的转子宜采用较大K值,而对临界振幅较小的转子可适当减小K值。
Abstract:In order to study the vibration problems of rotating machinery consisting of a two-span shaft around its critical speeds, a two-span rotor test rig was built, and two magneto-rheological dampers were installed on the two coupled rotors without changing the original support. Subsequently, by incorporating a proportion-integration-differentiation (PID) control method, a semi-active control system for the two-span rotor system vibration was established. Using vibration amplitude as the feedback parameter, the system controlled the electric currents of the magneto-rheological at any time allowing the rotor system vibration to be controlled online. In addition, in order to study how the proportionality coefficient influences the control effect, the value of K was varied. The experimental results indicated that the PID control system based on magneto-rheological dampers can successfully suppress the vibration of the two coupled rotors at their critical speeds. For higher values of K, the control effect is better, but very large values of K make the control effect worse. Therefore K should be large in the case of a rotor with a large critical vibration and smaller in the case of a rotor with a smaller critical vibration.
Optimizing control of a two-span rotor system with magnetorheological fluid dampers
Optimizing control of a two-span rotor system with magnetorheological fluid dampers

邢健,何立东,,黄秀金
- , 2015, DOI: 10.15918/j.jbit1004-0579.201524.0420
Abstract: A control system aims at vibration reduction in a two-span rotor system with two shear mode magnetorheological (MRF) dampers is designed. A finite element model of the MRF damper-rotor system is built and used to analyze the rotor vibration characteristics. Based on Hooke and Jeeves algorithm and the numerical simulation analysis, an optimal appropriate controller is proposed and designed. Experimental results show that rotor vibration caused by unbalance is well controlled (first critical speed region 37%, second critical speed region 42%). To reflect advantages of optimizing strategy presented and validate the intelligent optimization control technology, detailed experiments were developed on a two-span rotor-vibration-control platform. The influence on accuracy, rapidity and stability of optimizing control for rotor vibration are analyzed. It provides a powerful technical support for the extension and application in target and control for shafting vibration.
A control system aims at vibration reduction in a two-span rotor system with two shear mode magnetorheological (MRF) dampers is designed. A finite element model of the MRF damper-rotor system is built and used to analyze the rotor vibration characteristics. Based on Hooke and Jeeves algorithm and the numerical simulation analysis, an optimal appropriate controller is proposed and designed. Experimental results show that rotor vibration caused by unbalance is well controlled (first critical speed region 37%, second critical speed region 42%). To reflect advantages of optimizing strategy presented and validate the intelligent optimization control technology, detailed experiments were developed on a two-span rotor-vibration-control platform. The influence on accuracy, rapidity and stability of optimizing control for rotor vibration are analyzed. It provides a powerful technical support for the extension and application in target and control for shafting vibration.
磁流变阻尼器抑制转子系统振动试验
Experimental Study on the Rotor System Vibration Control by Magneto-Rheological Dampers

何立东,,,黄秀金
- , 2015,
Abstract: 针对大型旋转机械通过临界转速时振动过大及运行中故障频发等问题,搭建转子试验台,模拟启停机过程和碰摩、不对中故障。不改变原有支撑形式,安装自主设计的磁流变阻尼器,在不停机的情况下,试验研究阻尼器抑制转子通过临界转速时振动过大及各类故障振动。试验结果表明,阻尼器可以有效抑制转子系统临界转速附近的振动,降幅在60%以上;转子发生碰摩或不对中故障时,阻尼器可以降低其高倍频振动。
In order to solve problems such as overlarge vibration around the first critical speed of rotating machinery and high failure rate, a rotor bench is established to study the rotor vibration suppression effect by the designed magneto-rheological dampers. Rotor faults such as unbalance, rub and misalignment are imitated at the bench, and experimental research is done to study the rotor vibration suppression effect of the damper without stop. The results show that the dampers can suppress rotor vibration caused by those faults, by reducing the vibration around the first critical speed by 60% and eliminating the amplitude at high frequency caused by rub and misalignment.
轿车盘式制动器渐进特性研究
李福庆,刘昭度,付国,
北京理工大学学报 , 2008,
Abstract: 介绍了轿车盘式制动器制动力矩渐进特性的概念及其评价参数,研究盘式制动器制动力矩渐进特性.在制动器惯性实验台上,对轿车盘式制动器分别进行了不同制动初始温度、制动压力及制动初始速度条件下的恒压制动实验.实验结果表明,制动初始温度、制动压力及制动初始速度对渐进特性有不同程度的影响,并结合评价参数分析了这些因素的各自作用规律.
鸭akirin2基因克隆、序列分析与组织表达特性研究
代飞,,刘贺贺,韩春春,李亮,继文
牲畜兽医学报 , 2011,
Abstract: ?为研究akirin2基因在鸭生物体中的功能,本试验通过rt-pcr扩增了鸭akirin2基因,并采用荧光定量pcr方法检测了其在40日龄北京鸭不同组织中的表达差异。序列分析结果表明,鸭akirin2基因cds区全长594bp,编码197个氨基酸,氨基酸水平上与鸡的相似性达99%,其氨基酸序列二级结构具有哺乳动物akirin1和akirin2氨基酸二级结构域的共同区域;荧光定量结果表明,鸭akirin2在肌肉和免疫器官脾脏中都有表达。以上结果支持了鸟类akirin2可能具有与哺乳动物中akirin1和akirin2共同功能的观点,为进一步研究akirin2基因在鸟类肌肉发育中的作用奠定了基础。
关于混凝土捣制板应用的初析
郑忠
工业建筑 , 1995, DOI: 10.13204/j.gyjz199506009
Abstract: 本文通过对比分析的方法,从应用技术、施工方法、费用及其应用条件等诸方面,对混凝土预制板与捣制板的应用进行了较详细的论述。最后,对混凝土捣制板在民用建筑工程中的应用做了分析。
dna计算在人脸识别上的应用
,唐普英
计算机应用 , 2008,
Abstract: ?提出一种将dna计算结合奇异值分解(svd)应用在人脸识别的方法,旨在利用其超大并行计算能力,在大规模的人脸识别中大量快速地缩小目标识别范围,从而使得后续识别能使用较为成熟的一般方法。在对orl人脸库的实验中,有效地缩小了识别范围,使得dna计算在人脸识别上有了新的应用。
Application of DNA algorithm to face recognition
DNA计算在人脸识别上的应用

SHEN Kai,TANG Pu-ying,
,唐普英

计算机应用 , 2008,
Abstract: This paper proposed a new method of face recognition, which used DNA algorithm mixed with Singular Value Decomposition (SVD). It aimed to quickly reduce the recognition targets of large scale face database, and make the next recognition process use regular methods possible. The experiment was carried out on standard ORL face database. The result indicates this method avails and DNA algorithm realizes its application on face recognition.
人气指标与封闭式基金绩效相关性研究
Performance-Related Research of Sentiment Indicator and the Closed-End Fund
 [PDF]

,
Emergence and Transfer of Wealth (ETW) , 2012, DOI: 10.12677/etw.2012.22008
Abstract:
选取2008年3月~2011年12月25只封闭式股票型基金收益率和成交量、上证国债的收益率和成交量、3种人气指标(投资者信心指数,AR指标,心理线PSY指标)的周数据和月数据,建立基于周数据和月数据的计量回归模型,通过研究表明:1) 无论是在长期中还是在短期中市场的人气指标与基金相应期间的收益率成正相关性;2) 在短期中,基金的交易量与基金的收益率成正的相关性,但在长期中,基金的交易量已经不能对基金的收益率起解释作;3) 股票型基金的收益率与国债的收益率,成交量成负相关;4) 本期人气指标对本期的收益率起到正相关性,但对下一期的收益率解释力很弱。
Through the measurement regression model depending on weekly and monthly data of the returns and volume of 25 closed-end fund and the Shanghai bonds from March 2008 to December 2011 and three kinds of popular indicators (Investor Confidence Index, AR targets, indicators of psychological line PSY during the same period, we can find four important conclusions: 1) Whether long-term or the short-term, the market sentiment indicator and the Fund show a positive correlation; 2) In the short term, the fund’s transac-tion and the returns of the fund show a positive correlation, but in the long term, the fund’s transaction can’t explain the retunes of the Fund; 3) The returns of the fund and the returns of the bonds show a negative cor-relation; 4) Current sentiment indicator explain the returns of the funds for the same period, but the power of the explanation is weak for the next period.
谈谈图书固定排架的好处

中国图书馆学报 , 1959,
Abstract:
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