介质损耗测试仪校准方法研究

目前,我国用电量越来越大,人们也越来越重视用电安全。想要保证用电安全,就要使电路稳定运行,更要正确使用设备,确保设备的参数和检测更加精准。设备的校正不仅可以促进电网正常运行,这也可以促进我国经济发展,本文结合介质损耗测试仪的原理和使用方法、校准方式进行研究。     

单层带通FSS的带内传输损耗机理

阐述了平面波在无限平面单层频率选择表面(FSS)中的带内损耗机理,区分失配损耗和介质损耗,基于模分析法研究了诸多因素对损耗特性的影响.介质有耗时,TE波大入射角下损耗最大;阵列分布或单元缝隙影响带宽的同时,介质损耗与带宽总是呈相反的趋势;单侧介质加载的带内传输损耗主要是由介质损耗还是带内反射所致取决于介质厚度,但任何厚度的介质覆盖均比衬底时的带内反射要小;对称加载时则主要为介质损耗,且低于单侧加载.     

陶瓷粉填充聚四氟乙烯复合介质板介质损耗控制研究

低介质损耗是电子装备高频化对复合介质板提出的关键需求之一。陶瓷粉填充聚四氟乙烯复合介质板介质损耗性能的影响因素较多,其控制技术是该类型复合介质板国产化研究工作的关键技术之一。结合研究的工作体会,对影响聚四氟乙烯复合介质板介质损耗性能的因素进行了分析,对控制措施进行了研究讨论。     

10 kV交联聚乙烯（XLPE）电缆超低频介损检测及老化状态评估

本文分析并阐述了应用超低频介损测试在评估交联聚乙烯电缆绝缘老化状态中的有效性,同时对某地市21条10 kV电缆进行超低频介损试验。在分析超低频介质损耗与绝缘老化之间关系的基础上,依据IEEE 400.2—2013规定,使用超低频（小于1 Hz）现场测试仪进行了分析。结果表明：21条电缆中有9条处于需要进一步测试或维护的状态;电缆投运越长,故障越多,老化程度越严重。充分证明了超低频介损测试仪可以有效评价交联聚乙烯电缆的绝缘老化状态,对指导当地配电网电缆的改造具有重要意义。     

GWS-1型光导微机介质损耗测试仪

<正> 福建省凯特新技术联合开发中心与福建省电力试验研究所联合开发生产的GWS-1型光导微机介质损耗测试仪被评为1992年国家级新产品,并在1992年第四届国际能源(电力)展览会上获得技术进步奖。该机属国内首创,是一种新型绝缘材料测试仪。该机完全摆脱了通常的平衡电桥测量原理,采用微机进行数据处理,光纤传递高低压端信号,并引入抗干扰系统,     

微波陶瓷介质谐振器优选组合检测法

微波介质陶瓷材料的介电性能主要由3个参数表示:介电常数、介质损耗和谐振频率温度系数.本文优选组合了3种检测介质谐振器方法:短路型介质谐振器轴向的短路界面测定方便准确,用于测量微波介质陶瓷材料的相对介电常数;开路型平行板与介质谐振器无直接接触,用于测量介质损耗系数;自行研制的旋转开放腔,可同时放置多个样品,加快温度系数的测量速度.3个参数采用3种不同测试法,充分应用了不同测试法各自的优势,满足微波介质陶瓷材料介电常数跨度大、介质损耗低、温度系数快速测量的需求,可得到精确、快速的测试效果.     

一种IGBT管损耗在线测试仪

本文简要介绍了一种ＩＧＢＴ管损耗在线测试仪的结构原理。该仪器采用了动态采集技术，可对ＩＧＢＴ管的各参量进行在线测量并计算出实际损耗。     

发电机定子线棒介质损耗影响因素分析

通过试验对影响发电机定子线棒介质损耗的因素进行了分析,结果表明:发电机定子线棒介质损耗因数的大小与制造工艺、绝缘厚度、绝缘材料等因素有关。     

数字化介质损耗测量系统的研制

针对传统的介质损耗测量方法自动化程度低、工作量大且操作复杂的问题,以电子技术和PC技术为基础,设计开发了数字化、自动化介质损耗测量系统。该测量系统可以工作于两种模式,具有配置灵活、自动校准、自动量程等特点,可实现介质损耗角正切的快速测量、数据储存与分析、各种报表输出等功能。通过现场测试,并对数据进行分析,表明该测量系统抗干扰能力强,测量结果准确。     

光时域智能测试仪在光纤测试中的应用

介绍了光时域智能测试仪的一般工作原理,讨论了光纤损耗,并针对在光纤长度、光纤损耗等进行测试时存在的测试误差问题,给出了熔接、对接衰耗、测试盲区、不同折射率的光纤测试解决方案,从测试使用角度出发,介绍了降低测试误差,并提高测试精度的方法。     

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。     

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.     

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....     

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.