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磁流变液是未来应用最广泛的智能材料之一,它在无外加磁场作用下表现出良好的流体特性,在强磁场的作用下它的粘度会在毫秒级的时间内增加两个数量级以上,表现出类似固体的特性,一旦去掉磁场又立刻恢复液体的特性.这种可逆、迅速、易控的特点使磁流变液在机械工程中得到广泛的应用,其中包括表面光整加工,如将其用于光学镜片的表面研磨.目前其加工对象仅限于非导磁性材料,而现在绝大多数的机械零件的材料为导磁性材料.文章明确了磁流变液光整加工方法的主要优点;根据加工机理分析和初步实验研究,概括出将磁流变液用于导磁性材料表面光整时碰到的具体问题,并有针对性地提出了合理的解决方法. 相似文献
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The magnetorheological (MR) fluid damper-based semiactive control systems have received considerable attention for protecting structures against natural hazards such as strong earthquakes and high winds. In this paper, a novel modal controller using wavelet packet transform (WPT) is proposed for the vibration control of distributed structures. In the proposed control system, the WPT method is utilized to decompose the acceleration measurement and select the modes containing most of the WPT energy component as the dominant modes. Then, a modal controller is designed to control the dominant modes and the optimal active control force is solved. Finally, Clipped-optimal con- trol law is adopted to determine the voltage applied to each MR damper. A Kalman-filter observer, which estimates the full controlled modal states from local accelerometer feedbacks, is designed for rendering the controller to be more applicable to distributed structures with a large number of degrees of freedom. A numerical example of a stadium roof structure installed with MRF-04K damper is presented. The effectiveness of the controller is evaluated under both Tianjin and El Centro earthquake excitations. The superior performance and adaptability of the controller for versatile loading conditions are demonstrated through the comparison with traditional truncated modal controller. 相似文献
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研究了一类特殊完全r-部图K(r,n,n,…,n,n-1)的邻强边染色.证明了当m r≡0(m od2)时,有x'as(K(r,n,n,…,n,n-1))=n(r-1). 相似文献
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定义了广义基本有限生成的TS1-模.主要证明了广义基本有限生成的TS1-模的广义基本有限生成的type子模是广义基本有限生成的TS1-模;M是广义基本有限生成的TS1-模当且仅当对M的任意广义基本有限生成子模N,存在KIM,使得N≤geK. 相似文献
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基于人工登记与检索的元数据登记系统 总被引:4,自引:0,他引:4
文章简要介绍了元数据登记系统(Metadata Registry,MR),分析了基于人工登记与检索的MR范例系统DCMI MR、ROADS MR和DESIRE MR。 相似文献
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汽车磁流变半主动悬架的模糊控制 总被引:1,自引:0,他引:1
为带有磁流变液智能阻尼器的半主动汽车悬架系统设计了一种模糊控制器:将半主动悬架相对位移的误差及误差变化率作为模糊控制器的输入,阻尼力作为其输出,利用磁流变液智能阻尼器的阻尼力随电流变化的特性使车身的振动降到最小。仿真实验给出了最优被动悬架和模糊控制智能半主动悬架在随机路面激励情况下的响应曲线,结果表明,磁流变半主动悬架系统采用模糊控制效果较理想,其车身垂直加速度等参数变化幅度也有所降低。 相似文献
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研究双解析函数在光滑敞开曲线上的Riemann边值问题 利用解析函数Riemann边值问题的标准函数和特征双解析函数的Plemelj公式 ,得到了问题 (R)一般解的表示式 ,建立了问题 (R)的线性无关的个数与指标之间的关系 相似文献
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INTRODUCTIONAlthoughmanyeffortsweremadeoverthepastdecadestounderstandthedynamicbehaviorofcable-stayedbridges(WilsonandGravelle,1991),verylittlehasbeenreportedintheliteratureabouttheirseismicresponse-controlanalysis.Eveninthosestudiesreported,onlyuniformearthquakemotionwasassumedalongtheentirebridge(NiandSpencer,2000;Jungetal.,2001;Yozo,2002).Thisassumption,however,maybeunrealisticforlongspanbridgessincethedifferencesingroundmotionamongdifferentsupportsduetotravelingseismicwavesmayresult… 相似文献