孔的电解加工技术

现代孔加工要求越来越高,孔电解加工因其独特的优势引起了广泛的关注。为提高孔的电解加工质量,需全面了解当前的孔电解加工水平。从电解加工电极、运动控制、电源和电解液优化及其循环等方面对国内外孔电解加工的研究现状及其相关技术进行了系统总结,可知采用脉冲电流、改变阴极形状、改进电极进给方式等都能有效提高孔的电解加工质量。最后指出了孔的电解加工技术的研究趋势。     

基于转向节锥孔加工的夹具及辅具设计

对汽车转向节锥孔加工工序进行了相关的分析,在此基础上设计了该工序的专用夹具,使得锥孔的加工质量、生产效率有了明显的提高,同时降低了制造成本。为保证锥孔的精度和深度,满足转向节锥孔的加工要求,设计了加工该锥孔的辅具即锥孔定深装置,该装置降低了机加人员的操作难度,又能提高加工精度和加工零件的一致性。     

缸盖凸轮轴孔的加工精度研究

研究了切削刃、引导孔、冷却液和环境温度等方面对缸盖凸轮轴孔加工精度的影响,提出了从以上几个因素出发提高缸盖凸轮轴孔加工精度的方法,确保了缸盖凸轮轴孔加工精度的有效控制和提高.     

Design Special Fixture and Aids Based on Manufacturing of Steering Knuckle' s Taper Hole

对汽车转向节锥孔加工工序进行了相关的分析,在此基础上设计了该工序的专用夹具,使得锥孔的加工质量、生产效率有了明显的提高,同时降低了制造成本.为保证锥孔的精度和深度,满足转向节锥孔的加工要求,设计了加工该锥孔的辅具即锥孔定深装置,该装置降低了机加人员的操作难度,又能提高加工精度和加工零件的一致性.     

在数控车床上应用枪钻技术加工深孔零件

介绍了一种新型深孔零件的加工技术,利用数控机床精度高的优点和枪钻技术良好的加工特点,实现了在数控车床上加工深孔零件的目标,既保证了深孔的加工精度,也丰富了深孔加工方法,提高了设备的利用率.     

双柱坐标镗床加工斜孔专用夹具设计

这里分析了双柱坐标镗床回转工作台夹具加工斜孔的缺点,设计了一种孔加工专用夹具,提高了加工精度,简化了计算,加工效果很好。     

一种深孔加工机床的结构设计

深孔钻床是加工深孔零件的专用设备.钻深孔时为保证加工质量、提高工效,加工中钻头的冷却和定时排屑是需要解决的主要问题.深孔加工的特殊性决定了加工过程中切削热不易传播,无法直接观察切削状态;刀具容易磨损,排屑困难,且被加工表面质量无法保证.文中介绍一种新型深孔加工机床,它满足了深孔加工机床用产品的需求,提高了生产效率、降低了生产成本.     

基于机械加工的深孔加工技术研究

随着我国机械化工艺水平的日益提高,在生产活动期间深孔加工技术的应用越来越广泛。然而,在机械加工领域,深孔加工技术存在各种问题,一定程度上阻碍了技术水平的提高。文章主要介绍深孔加工技术的重点与难点,分析在机械加工中提升深孔加工技术的有效措施,为机械加工可持续发展打下坚实基础。     

深孔钻床加工偏心细长孔的方法

介绍了深孔钻加工偏心细长孔的方法。与用镗床加工相比,用深孔钻床可以提高加工效率,降低成本。     

航空发动机风扇单元体高效孔加工技术

论述了涡扇发动机风扇单元体孔的特征、加工难点和加工刀具的设计思路。针对特征孔加工周期长、质量差的问题,设计了新型加工刀具及改进加工工艺路线,提高了加工效率和零件质量,形成一套高效的孔加工方案,有利于提升航空发动机整体制造水平。     

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.     

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.     

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....     

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.