起重机变频调速控制技术

介绍了国内外起重机电气控制系统常用的几种交流调速技术,并对其进行了对比分析,最后给出了变频调速控制系统的原理方案.对变频调速控制技术若干关键问题进行了详细的分析,包括溜钩技术、再生制动能量处理技术以及定位与防摆控制技术等,指出变频调速控制技术已成为高性能交流调速领域中备受关注和重点发展的技术之一.     

基于变频技术的煤矿皮带运输机调速系统的应用研究

从变频调速技术的内涵入手,介绍了变频调速技术在运输机中的应用优势,最后从初始阶段、运输阶段、变频调速阶段对变频技术在煤矿皮带运输机调速系统中的具体应用进行分析。在煤矿皮带运输机中应用变频技术有助于延长皮带的运输机寿命以及节约成本。     

变频调速技术在集中空调中的应用

论述了变频调速控制系统的工作原理及性能优点,以及集中空调系统中应用变频调速器节能的基本原理,对变频调速器与阀门调节节能情况进行了研究,通过实测数据证实了变频调速器的节能效益.提出了变频调速技术是一项值得推广应用的新节能技术.     

电厂锅炉风机的变频调速节能技改

对电厂锅炉风机的变频调速技术作了简要介绍,分析了变频调速技术的节能性,并通过具体实例说明了应用该技术所得到的节能效果.     

浅谈交流电动机变频调速技术及应用

当前交流变频调速技术得到了迅速的发展,并有取代直流电动机调速的趋势,现重点介绍了交流异步电动机变频调速系统原理及应用技术.     

交流变频调速技术在船舶电力推进系统中的应用

随着新型电力电子器件的发展,交流变频调速技术成为现代交流传动调速技术领域的主要标志之一,本文着重介绍了交流变频调速技术的原理,及其在船舶电力推进系统中的应用.     

变频调速技术在煤矿电机中的应用研究

介绍了变频调速技术的优势,对变频调速技术应用过程中应注意的问题进行了分析,阐述了变频调速技术的理论基础与控制策略,并就变频调速系统的硬件组成进行了探讨。     

变频调速技术在煤矿风机上的应用探析

在分析变频调速技术风机运行原理的基础上,分析了变频调速技术的三点作用以及变频调速技术在煤矿风机中的三点应用功能,分别是:保持恒压供风模式;实现风机的软启动;改造传统风机变频调速系统配置;自动切换操作模式;报警自锁功能;风机双运行模式。     

略谈变频技术在煤矿机电设备中的应用

变频技术是应交流电机无级调速的需要而诞生的,是交流拖动的一种控制技术,通过改变电源频率的办法,实现控制目的,达到预期的控制目标.讨论了变频技术在煤矿机电设备中的应用,简要叙述了变频技术的基本概念、发展概况和其在矿用空压机、通风机控制系统中所发挥的积极作用.应用表明：变频器具有相对完善的调速功能和较为明显的节能优势,有着积极的推广价值.     

变频调速技术在搅拌器中的优化应用

介绍变频调速技术的原理,通过应用变频调速技术适时控制机泵及搅拌器电机转速,使电机在输出相同转矩的同时电流减小,从而达到降低功率、减少功耗的目的.     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.