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分析了旋转机械状态监测与故障诊断研究的重要意义。提出了一种由状态监测与故障诊断理论和方法、状态监测与故障诊断关键技术、状态监测与故障诊断系统、状态监测与故障诊断工程应用四个方面相互支撑的旋转机械状态监测与诊断研究的体系架构,给出了一个超超临界汽轮发电机组状态监测与故障诊断系统研究的实例。分别综述了大型旋转机械状态监测与故障诊断的理论和方法、关键技术、应用系统研究及其工程应用的进展,提出了对于旋转机械状态监测与诊断研究的思考与建议。 相似文献
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本文就超声波换能器所用材料进行了分析与讨论,介绍PZT的结构、相图与制备方法,重点对PZT的掺杂改性进行了研究与总结,最后介绍了关于PZT的当前的研究热点与研究方向。 相似文献
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《计算机集成制造系统》2017,(3)
针对目前国内外云制造服务评价理论与方法的研究情况,阐述了云制造服务的概念、特点及服务流程,研究了云制造服务评价理论与方法研究的目的,分析了云制造服务评价理论与方法研究的现状。同时针对目前服务评价理论与方法存在的问题,从不同角度给出了观点和相关建议,并提出了未来的发展方向,为今后云服务评价理论更深入的研究奠定了一定的基础。 相似文献
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《计算机集成制造系统》2014,(2)
工艺规划与车间调度是连接产品设计与制造过程的两个重要环节,介绍了工艺规划和车间调度的主要任务及两者的关联关系。概述了计算机辅助工艺规划的研究发展历程,总结了计算机辅助工艺规划的主要研究方法,指出当前研究存在的不足;从车间静、动态调度实现方法两方面综述了车间调度问题的研究概况。同时,分析了工艺规划与车间调度独立串行研究存在的问题,指出对两者进行集成研究的必要性。在此基础上,从面向接口集成与面向功能集成对支持两者集成的模型进行了总结,并对静、动态工艺规划与车间调度集成优化实现方法的研究成果进行了综述。基于上述综述分析,给出了工艺规划与车间调度以及两者集成研究的发展方向。 相似文献
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In a recent paper, the Ritz method with simple algebraic polynomials as trial functions was used to obtain an eigenvalue equation for the free vibration of a class of homogeneous solids with cavities. The method presented is here extended to the study of a class of non-homogeneous solids, in which each solid is composed of a number of isotropic layers with different material properties. The Cartesian coordinate system is used to describe the geometry of the solid which is modelled by means of a segment bounded by the yz, zx and xy orthogonal coordinate planes and by two curved surfaces which are defined by fairly general polynomial expressions in the coordinates x, y and z. The surface representing the interface between two material layers in the solid is also described by a polynomial expression in the coordinates x, y and z. In order to demonstrate the accuracy of the approach, natural frequencies are given for both a two- and three-layered spherical shell and for a homogeneous hollow cylinder, as computed using the present approach, and are compared with those obtained using an exact solution. Results are then given for a number of two- and three-layered cylinders and, to demonstrate the versatility of the approach, natural frequencies are given for a five-layered cantilevered beam with a central circular hole as well as for a number of composite solids of more general shape. 相似文献
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The article provides a solution to the problem of contraction process modeling when measuring the flow of fluids and gases using differential pressure flowmeters. The article shows the feasibility of obtaining the coefficient of contraction from the mathematical model of the reduced/contracted flow of fluids or gases. An analytical expression is obtained for the coefficient of contraction, which agrees well with the results of the experiment. Analysis of this expression is performed and dependencies on the geometrical parameters of the pipeline and orifice plate are obtained. 相似文献
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Modern methods of implementation of the rule of positive gradient of mechanical properties are considered; this rule was formulated by I.V. Kragelskii and its application serves to minimize the friction and wear of solids. The given methods include the application of coatings with the method of finishing antifricton abrasion-free treatment; application of new metal-cladding lubricating materials; and creation of a nanostructural state of the surface iron nitride layer by nitriding steel with a positive gradient of hardness normal to the surface. 相似文献
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介绍了挖掘机液压系统的功率参数与流量控制机理,从液压系统的功率角度分析了液压挖掘机的功率控制方式,从挖掘机负流量液压系统与正流量液压系统的工作原理方面分析了其控制性能及优缺点,并总结了挖掘机负流量液压系统与正流量液压系统的技术价值、应用场合及改善方向。 相似文献
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V. P. Dragunov E. G. Kostsov 《Optoelectronics, Instrumentation and Data Processing》2009,45(3):234-242
Specific features of operation of one- and two-capacitor microelectromechanical converters (MEMC) of energy of mechanical microscopic vibrations into electric energy with a modulated electrode-gap magnitude and with allowance for the mutual influence of electrical and elastic forces are analyzed, and the characteristics of these two devices are compared. The main factors restricting the increase in MEMC power are demonstrated to be the effects of “collapsing” and the condition of conservation of positive rigidity of the system. Expressions for estimating the limiting MEMC parameters are derived. The possibility of electrical energy generation in the presence of “real“ sources of wide-spectrum microscopic vibrations is considered. 相似文献
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衍射光栅光谱仪和法布里-珀罗(F-P)干涉仪是两类非常典型和重要的光谱仪器。从波动光学的角度看,光栅衍射和F-P干涉都可看成是多波列的相干叠加。由于波列之间存在光程差,光的相干长度限制着同时参与相干叠加的最大波列数。针对现有理论将光栅衍射和F-P干涉同时参与相干叠加的最大波列数分别定为透光狭缝总数和无穷大的情况,分别引入有效透光狭缝数和有效透射光光束数来说明光的相干长度对衍射光栅光谱仪和F-P干涉仪这两类光谱仪器分辨本领的影响。 相似文献