天然气排液阀的设计

针对石化行业特殊工况用节能产品天然气排液阀的要求,重点介绍了该阀的结构和工作原理,通过分析临界开启状态下力平衡方程和阀座孔直径、主阀芯理论开启高度计算得到的结果,得出天然气排液阀关键零件阀座孔、控制架内腔尺寸,满足主要技术参数,排量达到设计要求的结论。     

轿车侧门闭合力差问题排查与整改

轿车侧门闭合力的研究有重要的意义,可以说通过一个车门就可以评价其设计和制造水平。介绍三厢轿车侧门闭合力状况、门闭合力的评价标准、门闭合力的影响因素,并针对某车型侧门闭合力差影响因素进行排查与整改,对整改过程做一个总结,为后期侧门闭合力差问题整改提供参考。     

浅析C80E(F)下侧门装配工艺

本文针对C80E(F)批量生产前期出现的制约生产能力的C80E(F)下侧门装配批量质量问题进行工艺分析,通过调整侧墙组对胎、改进下侧门折页座组对定位方式、增加侧墙组焊后侧柱及下侧板门框矫正工装及下侧门矫正工装等工艺措施,提高了下侧门折页座的组对尺寸精度、侧柱直线度、下侧板门框和下侧门平面度要求。该方案实施后结果显示C80E(F)下侧门与下侧板门框配合间隙超差及不均、下侧门倾斜、下侧门与搭扣间偏移造成相互间配合不上及开闭不灵活的批量质量问题得到了有效解决,保证了瓶颈工序上部钢结构车门装配质量,提高了生产效率。     

动车组客室侧门机构检修工艺研究

针对CRH2型动车组客室侧门机构检修检测要求,研制了便携式检修检测装置,在动车组单车整车无电状态下,驱动运行侧门机构,进行侧门机构滑轨清洗、检验管路气密性以及检测侧门机构与其他配件尺寸配合干涉情况;制定了侧门滑轨清洗工艺,采取清洗准备、清洗剂雾化、预清洗、滑轨清洗、清洗检验的工艺过程,实现对客室侧门滑轨内侧的无污染自动清洗;并研究了风管及油路泄漏检测工艺,实现对门驱动系统气密性/油密性检测,并通过运行异响判断客室侧门系统的部件磨损情况。     

发动机缸体顶面缸孔曲轴孔精加工工艺技术

以发动机缸体作为研究对象,主要从缸体顶面、缸孔、曲轴孔3个方面精加工尺寸进行论述。通过选用顶配进口加工中心及珩磨机,采用定制夹具及辅助支撑,并配以先进的刀具、优化CNC加工程序及机床加工精度,保证了产品的精加工尺寸要求,包括尺寸公差、形位公差、粗糙度、珩磨网纹等。该加工工艺技术可为相关机械厂在提高缸体顶面、缸孔、曲轴孔精加工精度方面提供借鉴。     

飞机复杂零件上大量小尺寸导孔的快速视觉检测

设计并实现了一套飞机复杂零件上大量小尺寸导孔的快速视觉检测系统MBMS,对其中的关键技术作了深入研究和讨论。采用将视觉检测与多轴数控运动机构相结合的导孔检测方式,提出了一种系统内外参数精确标定方法;详细讨论了检测程序的生成方法,对检测中导孔的检测顺序进行了规划;针对飞机零件上导孔的成像特征,提出了一种高精度、高稳定性的图像定位技术;最后通过导孔的实际成像与基于虚拟相机技术的理论成像对比分析来得出导孔加工精度的评价。该系统为复杂飞机零件上的大量小尺寸导孔提供了快速有效的数字化检测手段。     

微小群孔阵列的照相电解加工技术研究

微小群孔结构广泛地应用于各领域,其加工技术日益受到关注.基于照相电解加工理论,研究了电解液浓度、电解液压力、加工电压等参数对群孔加工结果的影响.研究表明,高电压、高电解液压力能有效提高微小群孔的尺寸均匀性;低电压、低电解液浓度能显著降低微小群孔的锥度;采用高低电压结合的方法进行加工,获得了较好的群孔尺寸均匀性,降低了群孔锥度,很好地满足了加工要求.     

一种测量轿车钳体卡簧槽至缸孔底面距离的量表

介绍了一种测量轿车钳体卡簧槽至缸孔底面距离的专用量表,该量表采用弹性测头结构,量表在测量时可实现自动定位,通过比较测量,读取被测尺寸偏差.该量表具有使用方便、快捷、准确、可靠的优点.     

空气冷却塔的设计改造

测定空气冷却塔筛板的孔径、孔数、开孔率、板间距、压降以及漏液速度等流体力学性能参数,并对试验数据进行理论分析及模拟研究,摸索出对大孔径（φ10mm）、大开孔率（〉20％）的无溢流筛板,给定塔径、空气、水量及流速,选择塔板筛板塔的结构（孔径为d0、孔心距为t、开孔率和板间距）进行迭代计算的设计计算方法。     

单配衬套的外圆尺寸

孔和轴的配合为过盈配合.当加工孔时,孔的实际尺寸比理论尺寸大几丝,甚至十几丝,根据配合性质,以孔的实际尺寸计算轴的外圆实际尺寸的方法.     

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.     

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。     

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....     

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.