硬同轴线系统装配过程优化

装配过程中出现的连接间隙、密封以及受力状况不佳等问题,直接影响了硬同轴线系统的工作性能。因此,解决硬同轴线系统装配过程中存在的问题,是保证其高可靠性的先决条件。文中通过剖析硬同轴系统的组成,分析故障原因,提出了硬同轴系统装配过程优化工艺方案。通过控制、检验同轴线间隙,划分安装段,设置测试点,监测入射与反射功率,确定补偿垫片尺寸以及安装前调试等手段,提高同轴线系统的工作性能。实践表明,这些方法具有较好的可操作性和较高的实用价值,优化了装配过程,提高了硬同轴线系统的可靠性。     

外导体工艺要点

1.产品结构形式硬同轴传输线一般由内导体和外导体组成,内导体和外导体由金属制成。图1就是一种同轴线圆弧弯的外导体结构,材料H62黄铜,内外表面镀银,要求充气0.03MPa不漏气。     

ITER馈线系统虚拟设计

根据ITER馈线系统特点，采用模板剖建零件库，利用分层装配技术进行装配，提高了设计效率。通过有限元分析，及早发现设计问题，提高了馈线设计的合理性。     

无线通信用超柔馈线制造工艺的研究

介绍了一种新型的无线通信用超柔馈线的内导体制造工艺,直接采用光滑铜管进行深度螺旋轧纹工艺来生产内导体,省去了铜带切边及焊接工序,提高了内导体的生产效率,可节约铜材,符合国家提倡的节能降耗的政策。     

ITER校正场线圈过渡馈线真空隔断传热及热应力分析

ITER校正场线圈馈线系统的真空隔断是过渡馈线中的重要组成部分,位于S弯盒与过渡馈线的接口处,用以保证S弯盒和过渡馈线中不同真空系统的独立性,便于系统维护.针对真空隔断的作用,介绍了其设计结构,使用ANSYS软件建立了真空隔断的热及结构有限元模型,考虑到热传导、热辐射及外部自然对流对真空隔断工作环境的影响,计算了其温度分布、低温区的热载及其热应力,结果验证了真空隔断结构设计的可行性,为真空隔断的进一步优化及试制奠定基础.     

5—20/5t桥式起重机端梁角尺弯板装配胎具

双梁桥式起重机端梁角尺弯板是安装起重机车轮组的基面,其几何精度直接影响到起重机运行的平稳性和可靠性,是桥式起重机金属构件制造过程中的关键部位之一。目前制造厂均采用靠模拉线法装配角尺弯板,辅助时间长,误差大。本厂在总结靠模拉线法的基础上,设     

数控多线切割机床高精度罗拉轴的关键技术研究

为了实现石英晶体等非金属脆硬材料的高精度多线切割的目的,对高精度数控多线切割机床罗拉轴系统关键设计技术和装配工艺进行研究,本文设计了一种高精度多线切割机的罗拉轴系统的结构、温控、防砂系统,以及装配工艺,并对其主轴的温控、防砂和装配性能进行实验研究,获得了基本性能指标,对进一步研究脆硬材料切割加工技术具有重要的指导意义。     

基于模糊理论的配电网网架可靠性评估及规划研究

基于模糊理论,提出了一个配电网网架可靠性评估及规划模型。提出的模型通过评估配电网网架馈线的可靠性,将其作为配电网系统的规划指标。通过使用真实的配电网络数据测试了所提出模型的效果。结果表明,该模型能够根据所用数据找出影响配电系统稳定性的馈线,同时可以帮助确定配电系统规划方案。     

Pro／E在硬管零件中的应用

在工程机械产品中,有许多硬管类零件,或是要计算零件的长度,或是要为一些接头或法兰对形状复杂难以定位的硬管（如图1所示）设计装配焊接夹具。硬管有一个共同的特点：这些管路的煨弯方向与投影方向不是平行或垂直,而是一个空间的二面角。     

一种基于特征的快速装配方法

为提高模型装配效率,提出了一种基于装配特征的产品快速装配建模方法.该方法首先由用户根据装配特征定义产品装配模型,然后由程序自动将基于特征约束的装配模型转换为常规的基于几何约束的装配模型,从而实现快速装配.研究了装配特征表示、基于特征约束的装配模型和约束转换等关键技术,并以馈线结构快速装配系统为案例,验证了方法的有效性.     

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.