双螺线圈式液压油微污染物检测传感器

设计了一种多参数的油液污染物检测传感器,该传感器在单螺线圈电感式传感器的基础上,增加了一个螺线管线圈,可以进行电感检测和电容检测。电感检测可以区分油液中的铁磁性颗粒和非铁磁性颗粒;电容检测可以区分油液中水和空气。相对于传统单线圈式传感器,本次设计不仅实现了油液污染物的多参数检测,同时采用线径更小、匝数更多的螺线圈,增加了传感器的检测灵敏度。利用该传感器搭建的实验平台进行检测实验:电感检测时可以检测直径大于20μm的铁颗粒和直径大于80μm的铜颗粒;电容检测时可以检测直径大于90～100μm水滴和直径大于160～170μm气泡。该设计研究为油液污染物快速检测提供了一种新的方法,对于机械设备故障诊断与寿命预测等领域具有一定的意义。     

对置螺线管线圈的多功能检测模型及灵敏度研究

为丰富螺线管型传感器对液压油污染物的检测内容,提出并制作一种基于微流体芯片的对置螺线管型多功能检测传感器。理论推导了对置螺线管线圈的金属颗粒电感检测模型和非金属颗粒电容检测模型。为进一步提高检测灵敏度,试验对比分析了硅钢片对对置螺线管线圈的电感检测和电容检测的灵敏度。试验结果表明,硅钢片能够显著提升对置螺线管线圈的金属颗粒检测灵敏度,60～70μm铁颗粒和160～170μm铜颗粒的检测信噪比分别提升127.44%、222.07%,也能提高对置螺线管线圈的非金属颗粒检测灵敏度,但不显著,140～150μm水滴和240～250μm气泡的检测信噪比分别提升21.92%、7.95%。该研究对提高螺线管型传感器的液压油污染物检测能力提供了技术支撑,对液压系统健康状态监测以及故障诊断具有重要意义。     

基于空间微螺线管的金属颗粒检测研究

目前电感式线圈检测方式均是基于线圈的电感信号,对铁磁性颗粒的检测精度可达到粒径19μm,但对非铁磁性金属颗粒一直在100μm以上。基于颗粒在通过电感式线圈的时候能同时引起线圈电感和电阻的变化,以及二者都随线圈激励电源频率变化而改变原理,建立粒径为108μm的球形铁、铜颗粒在1 V、1 MHz的激励电源下的磁场模型,分析阻抗信号随线圈电流频率的变化,研究利用电阻信号提高非铁磁性颗粒的检测精度,并通过实验验证:当频率由0.2 MHz增加到2 MHz,铜颗粒电阻信号由0.005 5Ω增加到0.6Ω,电感信号由-0.000 4μH降低到-0.011 5μH,铁颗粒电阻信号由0.008Ω增加到0.3Ω,电感信号由0.43μH降低到0.38μH;相同频率变化范围内,铜颗粒的电阻变化为铁颗粒的2.04倍,铜颗粒的电感变化为铁颗粒的22.2%;利用2 MHz激励电源检测电阻值变化提高了非铁磁性颗粒的检测精度,检测得到最小粒径为20μm的铜颗粒。     

高精度双线圈式磨粒传感器的设计及研究

提出了一种可检测电感和电阻参数的高精度双线圈式磨粒传感器,其可对液压油污染物的检测提供技术支持.激励硅钢片和内置硅钢片通过磁化作用以及对磁场的聚集作用在检测区域中生成了高强度磁场,从而提升了传感器的检测精度.正方形检测通道的设计充分利用了两电感线圈之间的区域,提高了传感器的检测通量.试验表明,内置硅钢片不会改变磨粒传感器的信号噪声,有助于获取更优的信噪比.并且激励硅钢片和内置硅钢片对置区域的磁场强度最强,金属颗粒通过该区域时就会产生电感和电阻变化的脉冲峰值.在搭建的测量系统对油液中的金属磨粒进行检测试验,结果表明电感参数能够检测到25 μm铁颗粒和100 μm铜颗粒,电阻参数方式可检测35 μm铁颗粒和85 μm铜颗粒.通过结合电感参数检测结果和电阻参数检测结果,磨粒传感器可实现对25 μm铁颗粒和85 μm铜颗粒的区分检测.     

高精度微流体多参数液压油检测芯片设计*

在液压系统中,金属磨粒是影响液压系统正常运转的一个重要指标。所介绍的芯片是一种环形流道,基于电感电容原理的微流体油液金属颗粒计数器,当液压油中的磨粒、气泡和水滴流经空间微螺线管时引起了磁通量变化或介电常数的变化。用电感检测方法,在2 MHz的激励频率下使用27匝线圈能检测到30μm铁颗粒和110μm铜颗粒;用电容检测方法在1.3 MHz的激励频率下能检测到100μm的水滴和180μm的气泡。铁的检测精度明显提高,其余在原有的检测精度基础上提高了信噪比,同时增大了流道直径,检测液压油的通量变大,提高了检测颗粒的效率。改进后的芯片具有良好的实际应用价值与广阔的发展前景。     

一种基于微流体制备的电阻-电感式磨粒传感器

为了实现油液金属磨粒的高精度测量,基于微流体制备了一种可检测电阻-电感参数的磨粒传感器。通过仿真获得了金属颗粒在时谐磁场中的磁化和涡流效应特征,并通过实验研究了电阻-电感检测的电压特性和频率特性。高频激励可以增强金属颗粒内部的涡流效应,而激励电压对传感器检测结果的影响不大。研究表明电感参数对铁磁性金属的检测能力强,电阻参数对非铁磁性金属的检测能力强。采用2.0 V、2.0 MHz的激励,通过比较分析电阻和电感检测结果,该传感器可有效识别直径60μm的铜颗粒和直径16μm的铁颗粒。这种基于线圈电阻参数检测非铁磁性金属磨粒的方法为增强磨粒传感器的综合测量性能提供了新思路。     

液压油污染物双线圈多参数阻抗检测传感器

提出了一种液压油污染物多参数测量传感器,该传感器在平面型微流体电感传感器基础上增加了一个单层电感线圈,并将两个单层线圈正对排布在直微通道两侧,在电感参数检测的基础上将两个单层电感线圈等效为一对圆环形电容极板,引入了电容参数检测,从而实现了对液压油中铁磁性金属颗粒、非铁磁性金属颗粒、水滴和气泡4种污染物的检测。对该多参数传感器进行了设计,并结合仿真和实验对检测位置进行了优化,电容参数检测实验实现了液压油中180μm水滴和240μm气泡的区分检测;电感参数检测实验实现了液压油中80μm铁颗粒和150μm铜颗粒的区分检测。该研究对液压油多污染物的区分检测提供了一种新方法。     

高精度磨粒检测传感器的设计及研究

为了提高电感检测传感器对于非铁磁性金属磨粒的检测精度,提出了一种可实现电感和电阻参数检测的磨粒检测传感器。所设计的传感器主要由紧密贴合的环状硅钢片和平面电感线圈构成,硅钢片的加入增强了检测区域的磁场强度,使得金属颗粒的磁化效应和涡流效应更加剧烈,从而提高了电感和电阻检测精度。通过对比实验发现,环状硅钢片在提升检测精度的同时,并未增加电感及电阻检测信号的噪声;且电感检测和电阻检测都对铁磁性金属颗粒具有更强的检测能力;对于铁磁性金属颗粒,电感检测更为有效;但对于非铁磁性金属颗粒,电阻检测更为有效。将电感检测结果和电阻检测结果相结合,则可使用20匝的平面电感线圈实现对55μm铁颗粒和115μm铜颗粒的检测。本文提出的磨粒检测传感器可为液压油污染物的在线监测提供了技术支持。     

一种船机油液多污染物检测新方法研究

提出一种基于微流体芯片的新型油液多污染物区分检测方法,该方法设计的传感器由一个直通道微流体芯片以及嵌入芯片中的两个相同的单层线圈组成,不仅从电感原理对船舶液压油中的铁磁性和非铁磁性金属颗粒进行区分检测,也能从电容原理对油液中的水滴和气泡进行区分检测。相较于传统单线圈电感传感器,该双线圈传感器不仅能够检测多种参数,而且具有更高的分辨率。从检测原理对该方法进行了仿真及分析,然后用该传感器搭建检测系统对油液中的多种污染物进行检测试验,在试验中成功检测到了油液中40μm的铁颗粒和110μm的铜颗粒;作为电容传感器时能够检测100μm的水滴和180μm的气泡。该研究对船机油液污染物的快速区分检测提供了技术支持,这对于船舶机械系统的故障预防与诊断具有重要意义。     

应用磁性纳米材料的电感式油液金属磨粒检测传感器

为了增加电感式油液污染物检测传感器的稳定性,提升对铁磁性和非铁磁性污染物的检测精度,设计了一种内置磁性纳米材料的电感式油液污染物检测传感器,螺线管线圈内部填充的磁性纳米粒子层可以提升检测区域磁场强度,增强磁化涡流效应。模型材料制作300μm的微通道穿过螺线管线圈和磁性纳米材料组成的传感单元,当污染物通过传感单元时,利用电感检测原理可以区分铁磁性和非铁磁性污染物。同时采用有无磁性纳米粒子层的两种传感器进行多组对比实验。实验结果表明,磁性纳米粒材料的电感式油液检测传感器具有更高的检测信噪比以及更低的检测下限,对于20～70μm的铁磁性颗粒检测信噪比提升了20%～25%,对于80～130μm的非铁磁性颗粒的检测信噪比提升了16%～20%。该方法基于微流控检测技术,具有体积小、检测信噪比高等优点,同时为液压油污染物快速检测提供了技术支持,对液压系统的故障诊断与寿命预测具有重要意义。     

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.