超低温薄膜压力传感器的研究

超低温薄膜压力传感器可用于液氢、液氮、液氧等低温环境的压力测量,目前国内外超低温压力传感器产品的工作温度最低为-200 ℃.文中主要介绍了对超低温薄膜压力传感器的研究,通过薄膜压力传感器设计和工艺技术研究,成功研制出超低温薄膜压力传感器,并在-253(液氢)～+60 ℃温度环境下进行压力传感器静态性能测试,结果表明传感器性能指标优异,实现了超低温薄膜压力传感器技术突破.     

石墨烯-聚合物柔性电容传感器制备及性能研究

为了研究不同微结构对柔性电容式压力传感器性能的影响,采用成本较低的旋涂技术制备了无微结构、单层微结构和双层咬合微结构的柔性电容式压力传感器。通过对三种传感器进行测试试验,对比分析了具有不同微结构传感器的灵敏度,同时,对具有单层砂纸微结构传感器的响应特性、重复特性和迟滞特性进行了测试分析。试验结果表明,在20 kPa的载荷下,具有单层砂纸结构的柔性电容式压力传感器相较于其他两种传感器具有较高的灵敏度,在0～4 kPa的压力范围内灵敏度为0.451 kPa-1,4～6 kPa压力范围内灵敏度为0.14 kPa-1,6～25 kPa压力范围内灵敏度为0.03 kPa-1。制备的传感器具有较强的响应特性、良好的恢复性和稳定性,能够适应柔性可穿戴电子器件的应用需求。     

几种新产品

1.高精度压力传感器美国Robinson-Halpern公司宣称它的144A系列高精度压力传感器可检测强腐蚀性的液体和气体的压力,可直接测量生产过程的压力、发动机的压力等,其精度为±0.1％。此类传感器分电压输出和电流输出两种。电压输出单元具有低输出阻抗(小于1Ω)性能,而电流输出单元则为高输出阻抗(大于3MΩ)。其量程有12种,压力范围从0～10磅/时～2到0～10000磅/时～2而电流量程从1～5mA和4～20mA。其中有些传感器可装上过载保护装置,过载量为150％～200％,它不会损坏单元装置或导致校验误差。传感器的测量元件为MOnel合金波登管,亦可用不锈钢弹簧。     

特种压力传感器

德国WIKA公司生产了一系列特殊的压力传感器。过去在挤压机及注塑机加工时,对高温塑料的压力测量一直是塑料加工的难题之一。WIKA公司现在生产的这一系列特殊压力传感器可以使用到材料温度达400℃。这种压力传感器的测量范围为:0～50巴至0～2000巴,可提供的传感器精度为:0.5％和1％,其输出可为电压,也可为电流。目前销售的有4     

微型压力传感器

德国奥芬巴赫霍尼威尔公司(Honeywell,Ofpenbach)最近推出了一种新型微型压力传感器。这种微型压力传感器的工作电压为5VDC,输出电压为0.5～4.5V,它与施加的压力大小成正比。新推出的压阻式压力传感器用于负压、表压、绝压及差压测量、测时范围为0～345毫巴或0～1巴,其扁平塑料外壳具有电路板插装引线。     

喷印柔性压力传感器试验研究

柔性压力传感器是智能机器人和生物医疗等典型应用领域中的关键部件。针对10～50 kPa中等压力下对柔性压力传感器的高灵敏度、良好压力分辨率和快速响应需求,提出在PDMS基底上直写喷印石墨烯纳米片(GNPs)/多壁碳纳米管(MWCNT)构建S型折线图案化敏感单元,结合封装层微结构阵列,制备中压高灵敏度、低检测限的柔性压力传感器。试验结果表明,在压力为0～15 kPa和15～40 kPa的条件下,该传感器灵敏度分别为0.114 kPa–1和1.41 kPa–1,响应/恢复速度快(约100 ms/50ms)。同时,其也可检测低至约3Pa的微小压力。同时,该传感器更是能对不同发声进行准确的区分识别,对不同的指压信号进行精确稳定反馈。可见,喷印制造柔性压力传感器将为语音识别、人工假肢、制备高性能电子皮肤和医疗康复器件等提供可能的优选方案。     

环氧树脂封装的EFPI-FBG复合压力温度传感器

为了实现对液压管路中液压油的压力和温度检测,研制了一种EFPI-FBG复合压力温度传感器。对该传感器的压力特性以及温度特性进行研究。首先,介绍了以光纤F-P腔和光纤光栅为敏感元件,利用环氧树脂将EFPI-FBG复合结构经过封装保护构成压力温度传感器结构以及制作方法。接着,建立了压力温度传感模型,对传感器受力进行了理论分析,并使用Matlab和有限元软件分析传感器的压力灵敏度和温度灵敏度。最后对传感器进行压力和温度实验验证。实验结果表明,该传感器的压力灵敏度为2.83μm/MPa,温度灵敏度为1.97μm/℃,温度监测范围为10～80℃,应用于压力测量时的有效工作温度为20～65℃。此EFPI-FBG复合压力温度传感器具有良好的线性度,较小的回程误差,灵敏度高,抗震性能好,可用于液压管路中液压油的压力和温度测量。     

2CYJ型溅射薄膜压力传感器

溅射薄膜压力传感器是一种新型的应变式压力传感器。与其它应变式传感器相比,具有迟滞和蠕变小、长期稳定性好等优点。所研制的2CYJ型溅射薄膜压力传感器其精度可优于0.1%,个别指标,如重复性、迟滞可优于0.05%,工作温度范围为-55℃～+150℃。     

微机械梁膜结构1kPa量程压力传感器

采用微机械加工技术可以制作出管芯尺寸小而灵敏度很高的压力传感器。目前微压压力传感器产品的量程已达5～10kPa。本文介绍了采用微机械梁膜结构的压力传感器设计(PT—24),结合适当的工艺可以制成量程为1kPa的器件。     

高压压差传感器的研究

本文介绍了我们研制的一种新型压差传感器,该传感器可用于高基础压力下压力差的测量。本文首先叙述了压差传感器的基本原理和计算方法,然后给出了对该压差传感器在0～51MPa压力范围内进行标定的结果。实验表明,该压差传感器具有较高精度,可以满足实际测量要求。     

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.