PHD—50_C~B型锑电极酸度变送器

烟台市招远自动化仪表厂研制生产的该变送器被国家专利局授予专利,注册证号:90224017x。它是由锑电极传感器配以高精度信号转换电路,直接输出与酸度计pH值相对应的电流信号,其信号传送抗干扰能力强,可实现远距离传送。它采用高纯度锑作测量电极和银—氯化银环形固体参比电极。采用刮板式机械清洗装     

温度变送器的不确定度分析

温度变送器是一种将温度变量转换为可传送的标准化输出信号的仪表。温度变送器分为带传感器的温度变送器和不带传感器的温度变送器,不带传感器的温度变送器又分为热电偶输入信号的温度变送器和热电阻输入信号的温度变送器。     

具有频率输出的压力传感器

把非电量通过各种转换,变成测量方便的电量信号时,正在应用集成工艺。特别是采用集成压敏元件进行压力的测量。这类元件都为模拟输出信号,要进行远距离测量是困难的。本文研究一种频率输出信号的压力传感器,可离被监控物体10公里远处进行测量。压力传感器在结构上是一种模数装置,这种装置由集成桥式应变电阻结构的敏感元件、保护敏感元件和传递测量压力用充填变压器油的波纹管、集成电路电压一频率变换器以及不锈钢外壳所组成。由于传感器外壳的直径受到限制(因为它用在油井的深度测量仪器中),在由电压-频     

非接触式传感器的频率校正

光耦合非接触式测温传感器用热电阻直接测量温度,然后通过信号的转换,最后以光信号形式将温度信号非接触传送出去.信号转换过程中其稳定的频率会随集成芯片的更换而出现较大变化,利用脉宽调制的方法给予校正,以达到高精度的测量目的.     

美国引进频率变送器的分析

频率信号作为一项重要的电量参数，其性能指标的好坏一直受到人们的普遍关注。频率变送器是一种将被测频率信号转换为与其成线性比例输出的直流电流或电压信号的仪器，配以测量指示仪表或微机控制装置，可广泛地适用于电力系统和其他工业部门。本文粗略介绍一种由美国引进，实现频率信号测量的变送器电子线路，它将输入被测频率信号与内部石英晶体振荡器产生的标准频率进行比较后，转换成直流模拟电量输出。由于它准确度高，温度性能好，工作稳定可靠，也可作为实验室的频率监视标准计使用。该线路工作原理框图如图１所示。下面分别介绍各主…     

农田水利资源节水灌溉措施的分析

甘肃作为农业大省,推进农田水利节水灌溉工程建设,对提速优质本省农业生产意义显著。而且,在水资源持续短缺的大背景下,做大做强农田水利资源节水灌溉,正成为当前新农村建设的重中之重。以农田水利资源节水灌溉措施的分析探寻为题,在概述农田节水灌溉重要性认识的基础上,汇总农田常见节水灌溉技术,进一步阐述农田水利发展节水灌溉的对策和建议——坚持走内涵式节水灌溉发展思路、注重节水灌溉综合技术集成与配套建设、以较大流域为单位推广节水灌溉、兼顾节水与效益适中亩灌溉定额、重塑节水服务于社会的发展理念等等,以确保节水目标和农产品增收目标得到有效的实现。     

基于555集成定时器电路的脉冲变送器

研制了一种实用新型的脉冲变送器，主要电路部件为555集成定时器。结合传感器技术，脉冲变送器能准确可靠地完成对多种物理量的脉冲转换及长距离传送，并具有独特的抗干扰性能。在自动监测系统中起关键性作用。     

直流电压变送器的研究讨论

论述WB型直流电压变送器的工作原理、完成转换的各个模块电路的作用及变送器总电路的特点。文章研究的直流电压变送器可将0～75mVDC电压信号转换成为4—20mADC的信号,从而方便对微小的电压信号进行显示、记录或者自动控制,该电流输出型变送器有如下特点：可方便的直接安装在传感器接线盒内,可远传（1000m）、精度高、抗干扰、稳定性高、免维护。     

两线制4～20mA液压变送器的设计

工业控制过程中,经常要把模拟液压信号转化为可测的电压信号,然后经过换算,读取液压值.传统的方法是以手持液压计测量,这种方式简单、直接,但不适合远距离传输和智能化控制.针对这一局限性,首先分析了采用电流远距离传输信号的可行性,并设计了一种小巧、节能的液压变送器.研究结果表明,该设计结构简单,适合远距离传输和智能化控制,减...     

电量变送器

电量变送器是一种高精度的信号转换单元,它能将各种信号(指电压、电流或温度等)变换为归一化的电信号,供远动装置或计算机等使用,也可用于不同的自动化控制系统中。它的输出为直流信号(电压或电流),与输入成比例关系。电量变送器属于低压电器,这一点和其它二次仪表一样。它不能直接承受高电压和大电流。例如3.5千伏或更高、100～400安培。故应首先经仪用电压互感器和电流互感器之类变量器降低后,才能加到电量变送器。因此电量变送器的额定输入值与互感器     

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.