突扩燃烧室燃烧火焰深度二维温度场测量

针对电子耦合器件（CCD）辐射测温中因温度过高导致的辐射图像“发白”问题，提出了摄像机快门时间控制模型，该模型能有效地防止CCD光敏面输出过饱和电流。在此基础上，引入计算机断层图像检测理论，对燃烧火焰不同聚焦面的CCD成像过程进行研究，建立了用单一摄像机实现火焰深度方向聚焦面辐射图像与温度场分布关联模型，实现了火焰深度二维温度场的在线测量。实验室煤气燃烧实验表明：黑体炉标定后的关联模型实现了燃烧火焰内部温度场的在线测量与诊断，快门控制模型能有效解决辐射图像“发白”问题，扩大了CCD辐射测量的温度范围。     

新型单摄像机立体视觉传感器研究

提出一种用于测量空间三维点坐标的单像机视觉传感器模型。在结构设计方面,变传统的双CCD摄像机结构为单CCD摄像机结构,加装两组对称的光学反射镜,镜像出一对虚拟摄像机,可在同一个CCD像面上采集到存在视差的两幅图像,从而恢复空间点的三维信息;建立了标定数学模型,阐述了此视觉传感器测量模型的标定方法。相关试验表明,此测量方案不仅有效,而且经济快速,标定方法简单,对标定环境及靶标的摆放姿态无严格要求。     

基于数字图像处理的二维温度场测量

研究了CCD摄像机进行二维温度场测量问题。分析了彩色CCD摄像机测量机理,推导和分析了相应的三色温度测量模型。由于测量模型的复杂性和非线性,因此利用BP神经网络在函数逼近方面的特性,提出了一种用BP神经网络计算二维温度场方法。试验表明这种方法是可行的、并有较高测量精度,具有工业应用前景。     

基于光栅投射的光学三维测量仪的研制

利用商用数字LCD投影仪和数字CCD摄像机构成一套基于光栅投射的光学三维测量系统,介绍系统的测量原理、硬件结构和软件系统,最后给出该系统的一些测量结果。     

脉冲光纤激光诱导氧化硬质合金的温度场分布

利用ABAQUS建立了三维瞬态传热模型,计算了激光诱导下的温度场分布情况,并研究了激光参数对温度场的影响。仿真结果表明,工件最高温度随着单脉冲能量的增大以及扫描速度和光斑直径的减小而增大,热影响区的最大深度和宽度随着单脉冲能量的增大以及扫描速度和光斑直径的减小而增大。研究结果为优选激光诱导氧化硬质合金材料时的激光参数提供了重要依据。     

基于BP神经网络的空间相机的热光学分析

空间相机在轨工作时所处的热环境与地面状态差异很大,温度场的变化会给系统带来较大的热光学误差,影响成像质量.热光学分析是空间相机研制工程中的重要环节,是涉及传热、材料、机械、光学等学科的多学科问题.空间相机精密度高、结构复杂,包含很多非线性因素,增大了热光学分析的难度.利用成熟的BP神经网络建立相机温度分布与光学成像质量状况之间的网络模型,利用热光学试验获得的数据样本进行训练,并对其他样本进行预测,结果较好.     

三维火焰温度场光纤传感器设计

传统三维火焰温度场无损测量主要利用全息干涉方法或莫尔光栅方法，这些方法存在着测量系统复杂、成本高、数据获取困难等缺点。设计出一种基于多光谱辐射层析测温原理的三维光纤温度传感系统，系统具有使用灵活，测量精度高，获得数据便捷等优点。采用重排算法及MART技术相结合作为少投影数扇形束CT重建算法。四峰温度场模型的重建结果为确定光纤温度传感器旋转及扫描参数提供了依据。     

CCD图像灰度与照度的转换标定方法

本文提出了一种基于CCD摄像机利用图像灰度获得实际照度的新方法,该方法适用于摄像机的任意曝光和增益参数,且考虑了摄像机安装位置和角度对测量的影响。CCD摄像机照度测量法的实际应用主要涉及两个过程:一是标定过程,即应用CCD摄像机进行照度测量前,标定CCD图像灰度与照度之间的转换参数和转换模型;二是照度测量过程,即通过CCD摄像机拍摄图像,将图像灰度代入已定的转换模型,获得测量对象的照度值。其中,灰度与照度转换模型的标定是利用CCD摄像机实现照度测量的基础和关键,文中主要讨论了该模型的推导过程以及标定方法。具体为:首先通过理论推导获得图像灰度与CCD传感器感应的相对辐照度的关系,然后借助以均匀光源搭建的实验系统标定CCD传感器相对辐照度与物面实际照度之间的关系,进而获得图像灰度与物面实际照度的转换关系。在转换过程中讨论了曝光时间、增益以及CCD相机与照度测量点之间的距离和角度对转换模型的影响,为CCD摄像机照度测量法的实际应用奠定了基础。实验结果表明本测量及标定方法适用于摄像机任意曝光和增益条件,经过本方法标定后,应用CCD摄像机进行照度测量,测量结果的相对误差在4.5%以内。     

一种线结构光自扫描测量系统的研究

为了实现对复杂自由曲面的快速精确测量,提出了一种由CCD摄像机、振镜和激光线投射器组成的全视觉自扫描测量系统。该系统利用光学三角法确定了一种新的测量物体表面三维坐标的方式。基于该方式,此测量系统使用平面靶标实现了对摄像机内部参数的标定,借助振镜转动驱动激光平面完成了对摄像机视场内被测物体的扫描,最终根据激光平面方程和计算机二维平面图像信息获得了被测物体的三维数据。试验结果证明,该系统能以较快速度实现自由曲面的精确测量。     

TIG焊接温度场的有限元分析

建立了运动电弧作用下三维焊接温度场的计算机数值分析模型,分析中引入了热焓的概念和表面双椭圆分布热源模型,研制了相应的程序,具有较高的计算精度。用该模型对TIG焊接温度场进行了分析计算,得出了TIG焊接熔池的形状,尺寸和热影响区的温度分布。计算结果与试验结果吻合较好。     

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.