智能便携式温度仪

采用单片机作为智能便携式温度仪的核心器件,将所选热电偶传感器的分度表存入单片机内存,热电偶输出信号经滤波、放大后,输入至单片机内处理,通过查表及分段线性化方法取得相应的温度值.热电偶冷端补偿采用美国AD公司的专用集成电路芯片,与传统冷端补偿方法相比,温度补偿精度高.     

基于半导体控温的高精密低漂移测温系统

针对绝热加速量热仪对样品微弱放热的检测需求,设计了一种基于冷端及测量电路半导体恒温控制的高精密低漂移热电偶测温系统。系统采用低噪声仪用放大器ISL28634及32位高分辨率模数转换器AD7177-2实现热电偶信号数字化采集;通过高灵敏度NTC热敏电阻进行热电偶冷端测温补偿;利用半导体制冷片针对性控制模拟电路部分温度,使其工作于恒温稳定状态,抑制电路测温漂移。实验结果表明,系统在0~450℃范围内测温精密度优于±0. 005℃,2 h内平均每min测温漂移优于±0. 000 5℃。同时,将该系统应用于绝热加速量热仪,可有效提升仪器热安全评价指标——起始反应温度检测准确度。     

热电偶冷端补偿改进研究

在对现有热电偶测温冷端补偿电路进行分析的基础上,提出基于内置高精度温度传感器的模数转换芯片ADS1224的解决方案.为了提高精度和简化电路,将冷端测温电路与热电偶回路分离,冷端温度和热电偶电动势被独立进行测量,然后利用软件计算获得精确的热电偶工作端温度.同时文章也讨论了提高冷端温度测量精度的设计.实际应用说明该方案使得电路结构得到进一步优化,具有结构简单、成本低、精度高、稳定性高和抗干扰能力强等优点,具有推广价值.     

热电偶的冷端温度补偿与线性校正分析

针对热电偶校准过程中,参考端温度经常受到环境因素的影响发生变化,给校准结果带来很大的不确定性,因此需要对热电偶的冷端进行温度补偿。在传统冷端温度补偿方法基础上,提出一种基于内置冷结补偿器的精密放大器芯片AD8495的冷端温度补偿测试系统,并以K型热电偶为例对其进行线性校正实验,与微机结合验证该系统具有"低功耗,精度高,抗干扰"的优点。实际应用说明该方案具有高精度、宽范围、结构简单、抗干扰能力强等优点,具有推广价值。     

基于虚拟仪器的皮质骨钻削温度测量系统设计

对皮质骨在钻削过程中产生的钻削热进行测量和研究,提出一种基于Lab VIEW平台与亚为数据采集卡相结合的钻削温度动态测量系统。该系统采用人工热电偶作为温度传感器,芯片AD595作为信号放大元件,对钻削过程中的温度进行采集和处理,并通过计算机对所采集的数据进行实时显示、存储和查询,以及实现对热电偶的标定等功能,开发出一个相对完整的虚拟仪器温度测量系统。     

基于无线传输的热电偶测温系统设计

针对热电偶测量系统远距离进行温度监测时,存在信号干扰、布线复杂等问题,设计了一种无线通信的测量系统。该系统以CC3200为核心,根据TCP协议实现了采集端和接收端之间的点对点数据传输。采集端对热电偶信号进行调理,调理精度在±1.5℃之内,把AD转换数据传给无线发送模块,经接收端转发上传到上位机。实验结果表明,无线传输的信号稳定性及可靠性高。     

不用冷端参考点的热电偶测量装置

热电偶在许多测量任务中往往不能单独使用,因为它需要冷端温度装置(例如冰筒)。借助于AD594型热电偶信号转换器即可组成使用热电偶作为测量器件的测量线路,不再需要冷端装置。该集成块的主要优点是:价廉、使用方便,在5～15V范围内用单电源即可驱动,且可直接与J、K、R、T型热电偶连接。这种集成型转换器可用作极限值报警的测     

基于K型热电偶数据拟合的温度测量系统设计

针对K型热电偶测温的特性结合虚拟仪器技术,本文设计了一种具有高精度的温度测量系统。利用温度传感器AD592完成K型热电偶冷端自动补偿,仪用放大器完成对热电偶输出信号进行放大以满足数据采集卡对输入信号的要求,同时采用LabVIEW软件完成曲线拟合。测试结果表明,系统具有测量精度高、可靠性高、使用灵活等特点,当被测温度范围在10～180℃之间,测量的绝对误差小于±0.5℃,可广泛使用于要求较高精度温度测量的领域。     

基于K型热电偶的数字式测温仪设计

使用K型热电偶作为温度测量传感器,根据热电偶的冷端温度补偿设计制作数字式智能测温仪.把热电偶传来的信号进行放大及线性化处理,并通过矫正得到被测点的温度值.该温控器测温范围为-50℃～1 000℃,具有硬件电路简单、精度高、成本低、人机界面友好等优点.     

多路高精度热电偶采集板研制

为了满足工业应用现场多点测温的需求,研制了16路热电偶高精度数据采集板.选取ADI公司的高性能芯片ADμC834作为主芯片,利用其片上24位∑-△型A/D、外部高精度参考电压模块,结合信号调理电路和下位机软件的设计,实现了高精度数据采集.采用多路转换芯片,可实现了16路采集通道间的切换.采用热电阻PT100传感器采集热...     

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...     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

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.     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

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...