直线度全长误差评定方法的比较

本文介绍了对于线值表示的直线度全长误差的三种评定方法，在评定同一条误差曲线时，结果常常有较大的差别。指出在评定直线度全长误差时，应明确规定评定方法，不能将这些方法等同看待或混用。     

便携式激光准直仪及直线度误差测评软件的开发

开发了便携式激光准直仪及直线度误差测量、评定软件。该软件集成了基于PC的数据采集功能和步进电机控制功能 ,综合应用了直线度误差的两类测量方法和两种评定方法 ,可在多种直线度误差测量仪器上实现直线度误差的快速测量和误差评定     

评定直线度误差的三种算法及程序实现

讨论了评定直线度误差的三种方法,重点介绍了评定直线度误差的计算机精确算法,给出了相应的数据处理算法和程序框图,并用VB编写了评定直线度误差的Windows应用程序。通过实际运用,证明了算法和程序的有效性,可显著提高评定直线度误差的工作效率。     

基于坐标变换原理的空间直线度误差评定

基于坐标变换原理和增量算法,提出一种空间直线度误差评定方法.将空间直线度误差评定转化为平面直线度误差和平面点集最小外接圆的评定.通过对比实验验证了所提出方法的可行性,而且该方法数学模型简单、计算过程简便、评定精度较高.     

长导轨的直线度误差评定

论述了一种新的长导轨直线度误差的评定方法，它是通过计算机采用优化计算的方法，从而可以很快地获得直线度误差的精确值。     

直线度误差的计算机辅助算法

对直线度评定的三种常用方法进行了分析，给出了数学模型，并结合模型的特点给出了算法和程序流程图，为评定直线度误差实现计算机处理提供了理论依据。     

基于AutoCAD VBA的直线度和圆度误差评定软件的设计

直线度和圆度是形状精度的重要指标,为提高直线度和圆度误差的评定效率,实现误差评定的可视化,根据国家相关标准中规定的评定方法,使用AutoCAD VBA软件开发了一套直线度和圆度误差可视化评定软件.实验结果表明,所开发的软件不仅界面友好、使用方便,而且功能丰富,可实现直线度和圆度误差评定、误差可视化图形显示、测量数据输入输出和显示等功能.     

基于合像水平仪测量平尺直线度的不确定度评定

直线度误差的不确定度评定方法比较复杂,在实际测量评定中比较麻烦。为此,从直线度误差的测量、数学模型的建立、不确定度的评定、实验数据的采集到不确定度估计等过程,对直线度误差的评定和评定方法进行系统的学习,从而得到直线度误差的不确定度数值。最后,通过数据仿真验证不确定度评定结果的准确性。     

评定直线度误差数据处理方法的分析与比较

用基础的测量方法和数据处理方法对直线度误差进行评定。测量方法采用水平仪的节距法。数据处理方法采用两端点连线法、最小二乘法、最小区域法。每一种方法都分别用计算法和作图法评定直线度误差。采用不同的方法对同一组数据评定直线度误差,其结果不尽相同,并对其精度进行比较,从而得出应用这三种方法评定直线度误差的差别。     

任意方向上直线度误差的评定新方法

针对任意方向上直线度误差评定存在的非线性方程组求解困难、评定结果不精确、数据处理不能实现自动化等问题,提出将任意方向上直线度误差的评定问题,转化为给定平面内直线度误差与圆度误差的评定问题,推导数据处理方法与误差评定方法,并通过测量验证所提出方法的可行性。结果表明,所提出的方法不仅简单、易于计算机自动数据处理,而且评定精度比一般的方法提高约5%。     

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.