渗金属气压对光电高温计测温精度影响的实验研究

为准确控制双辉等离子渗金属工件的温度,借助自制的一套热电偶测温实验装置,对光电高温计测温进行了比对实验,探讨了气压对光电高温计测温精度的影响。实验结果表明:在双辉等离子渗金属过程中,对同一工件温度,随工作气压的升高,光电高温计所用的ε值也增大。工作气压每增高5～10Pa,将ε值提高0 1,这时光电高温计的温度测量误差会小于±3℃。     

光电高温计在双辉等离子渗金属测温中的应用研究

为准确测量双辉等离子渗金属中的工件温度，借助自行研制的一套热电偶测温实验装置，采用比对实验的手段，得出了在碳钢表面常规双辉等离子渗金属过程中，准确选定光电高温计的材料发射率修正系数的方法。     

碳素工具钢表面低温双辉等离子渗铬硬化的研究

用双辉等离子渗铬技术，进行了880-900℃温度下的碳素工具钢表面渗铬硬化研究，分析了渗铬硬化层的显微组织和相结构，测量了渗铬硬化层的厚度、硬度及铬浓度分布，并对渗铬硬化层进行了划痕检验。结果表明，在880-900℃温度下，对碳素工具钢进行双辉等离子渗铬也可得到良好的渗铬硬化层；渗铬硬化层由沉积层、碳化物层和固溶体层构成。     

T10钢表面中温双辉等离子渗铬强化的研究

用双辉等离子渗金属技术,对T10钢进行了880～900℃温度下的表面渗铬强化研究;检测和分析了渗铬强化层的显微组织、渗层厚度、硬度及铬浓度分布,并对渗铬强化层进行了抗磨损试验.结果表明,在880～900℃温度下,对T10钢进行双辉等离子渗铬,可得到良好的渗铬强化层.经双辉等离子渗铬强化的T10钢比常规热处理后的耐磨性提高了5～6倍.     

快速精密直流光电高温计的研制

本文提出了一种新型快速精密直流光电高温计,其最快测温速度为1000次/秒,最小测量目标直径为2mm。它采用单光路,直流测量方案,检测元件采用硅光电二极管,数据采集处理系统采用MCS-51单片计算机,使高温计具有四个不同的测温速度,直接显示和打印温度值和采样点序号,调零显示和自动标定功能等。该高温计具有测量快速,目标小,精度高等特点,并且体积小,结构简单,使用方便,是一台通用的高温快速测温仪器。文中还对高温计的特殊电路和温度方程的建立进行了讨论。     

提高高温盐浴炉控温精度

高温盐浴炉测温与控温,是温度测量上的一个薄弱环节。过去,我们曾采用过光电比色高温计、全辐射高温计、光学高温计测量,但这些仪表均属于非接触式仪表,受外界影响较大,带来很大的附加误差。另外由于烟雾及工件遮挡镜头,造成炉温升高、产品过烧而报废。近年来,由于采用了新钢种501代替W180r4V钢种,刃具材料的改变,使淬火温度允许误差变得小了。如W18Cr4V淬火温度为1275～1285℃,允许     

奥氏体不锈钢表面双辉等离子渗锆的动力学

利用双辉等离子渗金属技术在0Cr18Ni9Ti奥氏体不锈钢表面制备了一层均匀、致密、呈良好冶金结合的渗锆合金层,并对1 060℃下的渗锆动力学进行了研究。结果表明:随着距锆合金层表面距离的增加,锆元素的含量呈梯度递减,扩散系数逐渐减小,而扩散激活能逐步增大;在1 060℃采用双辉等离子技术渗锆时,渗锆合金层表层的空位密度为2.945×(1012~1013)cm-2,与相同温度下采用常规渗金属工艺相比,提高了1~2个数量级。     

高温盐浴炉连续测温新装置

在高温盐浴炉测温问题上,我厂曾采用过光学高温计和光电高温计。1979年自制过插入式光电高温计。但这些间接测温装置都存在着误差人的缺点。我们也采用过直接测温的方法,用刚玉管、石英玻璃管等,虽然能耐高温、抗腐蚀,但易碎裂。若采用不锈钢涂料法,又经不起腐     

高速钢工具盐浴淬火高精度测温

<正> 影响高速钢工具盐浴淬火质量的主要参数之一是温度,温度测量准确就有可能获得较高的淬火质量。目前,热处理工作者已经不满足于使用光学高温计和辐射感温计来测量盐浴温度,逐渐采用测量精度更高的测温工具直接测温。直接测温就是把感温元件—热电偶及其护管插入盐浴内,再通过二次仪表反映出温度。生产上要求感温元件应具有足够长的寿命,并     

铝合金高速铣削刀具温度分布的研究进展

在铝合金高速铣削过程中,刀具磨损现象严重影响刀具寿命和工件表面完整性。刀具温度是影响刀具磨损的主要因素,因此了解刀具温度分布是近年来研究的重点。准确测量高速铣削过程中的刀具温度是关键问题,人工热电偶法可以准确测量指定点的温度,是铣削加工中常用的刀具测温方法。通过查看相关文献,总结了高速铣削中刀具温度的理论方法以及测温方法,研究了无涂层刀具和涂层刀具高速铣削过程中铣削参数对刀具温度分布的影响,阐述了高速铣削过程中刀具温度分布情况,优化了铣削参数。     

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.     

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....     

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。     

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.