用于有机磷农药残留快速检测的酶法量热式流动注射分析检测仪

采用酶抑制方法,研制了一种适合农药残留现场速测和防范农药急性中毒的量热检测仪器。主要由流动注射分析系统、半导体恒温器、固定化酶反应柱、量热传感器、数据采集模块组成。半导体恒温器的控温精度为±0.1K,量热传感器的灵敏度为2mV/K。检测仪的空白响应为10mV,在1mg/kg敌敌畏时,得到29%～36%的相对抑制率。稳定状态下,能够在5min内完成测试,可以自动处理和存储数据。     

基于Matlab的电液微小数字阀测试平台

给出了微小数字阀的测试平台,介绍了测试平台的原理及组成模块,MATLAB/Simulink环境下信号采集建模及参数设置,实验结果表明,基于BNC2090数据采集系统的测试平台,在步进电机的分级连续跟踪控制方法下,能够快速、方便地测出阀心的运动特性.     

基于红外热电堆的矿用测温装置设计

目前煤矿测温装置多数采用有线接触式测温方式,针对传统装置存在的测量精度、实时性以及安装难等问题,设计了一种基于红外热电堆的测温装置。系统采用红外热电堆传感器采集温度信号,通过无线模块收发信号,将温度送至上位机,便于组成网络,实现多点测温。由于非接触特性,还能够实现对矿井下运动的设备温度进行测量,具有可靠性高、速度快、实时性强等特点。     

基于GPRS的高压开关设备远程温度监控系统

针对高压开关设备地域分布广而造成温度信号采集困难和设备难以及时维修的问题,开发了一种基于通用分组无线业务(GPRS)的远程温度测控系统,该系统的数据采集终端以数字信号处理器(DSP)为核心,利用热电堆传感器采集温度,通过GPRS模块连接Internet,利用动态域名解析的办法与监控中心建立连接,再把温度信号传到监控中心进行分析监控,并进行了相关测试。测试结果表明,该系统抗干扰能力强,工作稳定,可对历史数据进行分析,并可对高压开关设备的温度实施有效的远程监控。     

用于检测农药残留的量热式生物传感器的半导体恒温仪的研究

介绍一种用于检测农药残留的量热式生物传感器的半导体恒温仪的研制。该恒温仪基于塞贝尔效应,利用半导体制冷进行恒温。该仪器由恒温器与控制器部分组成。针对量热式生物传感器的参比法测量及流动分析的特点,恒温器采用相同结构参数的双流路对称布置。液体由流路下部流入,保证换热充分。控制器采用铂电阻采集温度信号,由智能调节器进行温度监控。可控温度范围由0～70℃;升降温时间短,不超过3min,控温精度小于±0 1℃。通过实验,恒温仪的恒温效果良好,控温精度高,符合检测要求。     

多通道环境下油样检测光谱分析系统的方案研究

对于光谱仪的信号采集系统的两个关键技术指标是微弱光电信号的处理和多通道数据的同步采集和传输。在分析信号采集的工作原理基础上，结合工程应用，研究了用于直读光谱仪的多通道数据采集与处理系统。基于微弱光电信号的特性和系统性能指标的需求，设计了以FPGA为控制核心、信号调理模块增益可控、多通道数据并行采集、实现数据无损传输的系统总体设计方案。设计了实现数据采集系统各功能模块的硬件电路，以及FPGA对系统各个模块的控制逻辑，并完成系统硬件测试和功能测试。测试结果表明本系统能够采集光电倍增管输出的微弱电流信号。     

基于FPGA和DSP的核磁共振两相流采集系统北大核心CSCD

为了满足石油工业中核磁共振两相流采集系统的高精度、低成本、小型化等需求,实现对核磁共振FID信号的采集、存储、传输及显示,设计了基于DSP和FPGA的核磁共振两相流采集系统。系统采用模块化设计,主要包括AD信号采集模块、双核控制传输模块以及上位机显示模块。采集过程主要依靠FPGA控制ADC完成数据的采集、存储、传输。然后通过DSP设计最优滤波器完成对信号的去噪处理,再由串口将数据传输给上位机进行反演处理以及显示。实验结果表明:该系统能够实现FID信号的采集、存储、传输及显示,去噪后的信号信噪比提升了34.6%,反演处理后的T2谱可以识别出不同含水率下的两相流。     

热电偶时间常数测试系统

介绍一种基于数字PID控制算法的热电偶时间常数测试系统,提出了以PDI-4型红外探测器输出作为反馈信号控制半导体激光器功率输出以实现在热电偶测温端处形成阶跃温升的测试方法。该系统由半导体激光器,反馈控制模块,椭球面反射镜,红外探测模块,热电偶及信号采集显示模块构成。在温度20℃,湿度59%,标准大气压的环境下,以上升时间,超调量作为控制器性能参数测试KQXL-18U-6型热电偶,测得其在上升时间0.8 s,超调量2%,阶跃温升1 020℃的温度信号激励下的时间常数为0.34 s。     

小型往复压缩机阀片冲击疲劳寿命测试系统的研究和实现

阀片是家用冰箱压缩机的关键易损部件,阀片的寿命主要取决于工作过程中的弯曲应力和冲击应力,阀片疲劳会导致冰箱能耗的增加甚至冰箱不能正常工作.为了研究阀片疲劳失效的规律,需要一套先进的阀片疲劳测试系统.根据阀片正常工作的条件设计了一套基于LABVIEW软件平台的压缩机阀片冲击疲劳寿命测试系统.该系统能够采集阀片测试过程中的声音信号并且对信号进行频谱分析,根据信号频谱特征检测阀片是否疲劳失效,提出的测试系统为压缩机阀片生产厂商和研究者提供了一种测试阀片冲击疲劳寿命的可行方案.     

基于虚拟仪器的扫描阀风洞数据采集系统研究

针对增压连续式风洞扫描阀测量系统的实验,设计了一种基于虚拟仪器LabWindows/CVI开发环境下的风洞扫描阀系统实验数据采集系统,阐述了该系统的方案设计,给出了系统的主要软件涉及构成及采集流程图。该系统为用户提供友好的人机交互界面和易操作性,完成对扫描阀测试实验系统模块参数、系统扫描参数、触发模式的信息配置,实现了对压力测试各通道数据的实时测量、显示、保存及打印输出。实验结果证实该系统提高了测量的有效性和可靠性。     

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.     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.