化爆材料瞬态切削温度的NiCr/NiSi薄膜热电偶温度传感器的研制

针对化爆材料的切削特点,研制出一种集切削和测温功能于一体的NiCr／NiSi薄膜热电偶快速响应温度传感器。用多弧离子镀将NiCr/NiSi热电偶薄膜直接镀于高速钢刀头内。薄膜热电偶电极与高速钢之间采用最先进的多层镀膜法绝缘,即用微波ECR等离子体源增强射频反应非平衡磁控溅射技术首次成功在W18Cr4V高速钢基底上沉积绝缘性能良好的SiO2膜。对研制的薄膜热电偶温度传感器进行了静态和动态标定,结果表明传感器在0- 600℃测温范围内具有很好的线性和热稳定性,而且响应快,时间常数小于0．8 ms。热电偶薄膜与绝缘膜、绝缘膜与基体之间有足够的附着强度。该温度传感器已安装在现场使用,为国防工业部门的高效、安全生产提供了有力的保障。     

NiCr/NiSi薄膜热电偶传感器的研制及有限元模拟

采用磁控溅射法,在刀具材料为W18Cr4V高速钢的后刀面上镀制了NiCr/NiSi薄膜热电偶。传感器既能满足切削要求,同时又能够快速采集温度信号,并对其进行了静态和动态标定,实验范围内线性误差为0.56%,时间常数为12.7 ms,响应迅速,满足实验要求。最后用ANSYS对传感器的瞬态响应和温度场分布进行了有限元仿真,并通过实验进行了验证。     

内燃机活塞表面瞬态温度传感器的研制

针对内燃机活塞表面温度变化迅速的特点,研制了一种瞬态温度传感器用于测量活塞表面温度。采用直流脉冲磁控溅射的方法将NiCr薄膜直接溅射沉积在高温烧结后嵌有NiCr、NiSi丝的陶瓷元件端面,NiCr薄膜外侧溅射Si3N4保护膜。传感器外壁选用带螺纹的304不锈钢作为铠装套筒。采用自行研制的薄膜热电偶静动态标定系统对所研制的瞬态温度传感器进行标定,结果表明:所研制的传感器在50~400℃范围内具有良好的线性和热稳定性,其塞贝克系数在39~41μV/K之间,非线性误差小于0.34%,重复性好;热接点薄膜厚度为355nm时,传感器的响应时间为41.7μs,且响应时间随着薄膜厚度的增大而增加;该瞬态温度传感器可以满足曲轴转速为1800r/min的内燃机活塞表面瞬态温度测试的需求。     

嵌入式薄膜热电偶测温刀具的设计

设计了一种嵌入式薄膜热电偶的刀具,以实现在切削过程中对刀具瞬态温度的实时测量。以刀具的前刀面作为基底来镀制薄膜,通过磁控溅射法在刀具前刀面制备了Al_2O_3绝缘膜、NiCr/NiSi薄膜热电偶以及Si_3N_4保护膜,最终制成了可以进行切削加工并能够实时测量切削温度的刀具。文中主要介绍了电极NiCr薄膜、Al_2O_3绝缘膜的制作过程及一些相关性能的检测,随后利用SolidWorks和DEFORM-3D对刀具进行了三维建模和切削过程的仿真模拟,得到了刀具的温度场分布。     

基于吸收系数修正的硅片激光弯曲模拟与实验

考虑热吸收系数随温度变化的因素,以硅为对象进行了激光弯曲模拟和实验。借助APDL语言编写了激光弯曲成形的仿真程序,对单脉冲作用过程进行模拟,以得到单点脉冲周期内的温度分布;采用NiCr／NiSi合金薄膜热电偶对单脉冲作用过程中的温度分布进行测量,对比上述的温度模拟与测量结果,修正硅材料的激光综合吸收系数为0．82。采用有限元分析软件实现了硅片的脉冲激光弯曲成形的仿真和模拟,并对硅片多次连续扫描的弯曲模拟与弯曲实验进行对比,误差仅为0．1°,验证了仿真程序的有效性,为硅片的激光弯曲成形提供了理论与实验依据。     

高性能薄膜热电偶制备及其铣削应用研究

随着纳米薄膜沉积技术的发展,基于薄膜热电偶的瞬态温度测量技术在多种场合得到广泛应用。为实现薄膜热电偶在铣削加工中的应用,提出了一种高性能薄膜热电偶的制备方法。通过直流脉冲磁控溅射技术在石英基底上制备了NiCr/NiSi薄膜热电偶,并于氩气气氛进行不同温度的退火,研究了退火对薄膜热电偶综合性能的影响。结果表明,500℃退火的功能薄膜均匀性、导电性均有显著的提高,薄膜热电偶的塞贝克系数由退火前的36.3μV/℃增大到最大值40.5μV/℃,在连续热冲击和高温保持6 h后测温性能仍保持良好。将高性能薄膜热电偶研究成果用于测温铣刀的研制,并用于TC4正交铣削,得到了TC4铣削温度预测公式,为旋转类刀具加工温度的测量提供了一种可行性方案。     

基于薄膜热电偶的高速切削动态温度监测系统设计

提出了一种基于薄膜热电偶传感器的高速切削动态温度监测新方法.采用磁控溅射、光刻技术、PECVD等方法在立方氮化硼(PCBN)高速切削车刀前刀面上沉积多层薄膜,制备NiCr/NiSi薄膜热电偶传感器.详细阐述了薄膜温度传感器的制备过程,设计了高速切削温度和切削力的数据采集与监测系统.以高速数据采集卡PCI-9118为硬件,结合Tchart控件,采用VC ++编制简洁友好的人机界面来实现对高速切削温度和切削力数据的实时采集、显示与分析.试验表明,设计的数据采集和监测系统使用方便、灵活、可靠.     

高速动车组轴温测量用特种结构薄膜传感器的研制

针对高速动车组轴箱轴承温度变化迅速的特点,研制了一种以NiCr/NiSi薄膜为敏感材料的特种结构薄膜传感器。采用自行开发的标定系统对直流脉冲磁控溅射技术制备的薄膜传感器进行动静态特性标定,结果表明所研制的薄膜传感器在30~400℃内具有良好的线性度,其塞贝克系数为37.84μV/℃,非线性拟合误差小于0.7%,动态响应时间为53.72ms。特种结构薄膜传感器磨损实验结果表明：传感器测温端的磨损对其温度测试的动静态特性影响很小,即测温端部分磨损不影响其测温性能。     

新型薄膜式热电偶切削温度测量传感器

研制了一种集成在刀头内的新型薄膜式热电偶。在切削的同时，能快速直接地测量切削温度。镀膜工艺采用了先进的磁控溅射和离子镀技术，成功地解决了绝缘、镀膜牢固性等问题。该热电偶测温接点位于刀尖，响应迅速，时间常数约为0．8ms；并且在0～600℃的测温范围内具有良好的线性和热稳定性。详细论述了传感器的结构设计、薄膜热电偶的制作、静态标定、动态标定以及检测电路。当应用于现场切削试验时，传感器能快速响应瞬态切削温度。     

硅片的激光吸收系数修正与弯曲试验

考虑热物性能参数随温度变化的因素,以硅为对象进行激光弯曲模拟和试验,借助APDL语言编写激光弯曲成形的仿真程序,对单脉冲作用过程进行模拟,以得到单点脉冲周期内的温度分布;并采用NiCr/NiSi合金薄膜热电偶对单脉冲作用过程中的温度分布进行测量,对比上述的温度模拟与测量结果,修正硅材料的激光综合吸收系数。采用有限元分析软件实现了硅片的脉冲激光弯曲成形的仿真和模拟,并对多次连续扫描的模拟结果与硅片弯曲试验结果进行对比,验证了仿真程序的有效性,为硅片的激光弯曲成形提供了理论与试验依据。     

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.