Study on separation algorithm of convolutive mixing model and separation of mixing signals of multiple partial discharges

To identify individual partial discharges(PD)signals produced by multiple insulation defects in gas insolated switchgear (GIS),this paper analyses the mechanism of propagation and mixing of multiple PD electromagnetic wave signals in GIS cylinder and proposes the convolutive mixing model to describe it for a separation algorithm to acquire individual PD signals. With the non-stationary property,mixing PD signals are changed at time domain into a set consisting of short-time stationary PD signals and then the Molgedey-Schuster decorrelation approach is employed to separate these stationary PD signals at frequency domain. The correlation of the envelope of separated PD signals in this set is used to reconstruct PD signals to realize the separation of non-stationary UHF PD mixtures. The effective separation of actual UHF PD mixing signals validates the assumption of convolutive mixing process in GIS and also offers a new approach to the identification of mixing PD signals by external ultra-high frequency detection scheme from multiple insulation defects in GIS.     

The image definition improved algorithm for hot continuous castingbillet surface defects inspection

In the hot continuous casting billet surface defect inspection system based on machine vision, acquiring a high signal-to-noise image is the key for successful inspection. To solve the disadvantages existing in current machine vision engineering, a new algorithm with improved image definition is presented based on both focus window and CCD target area illumination parameters. It selects a target object from series of hot continuous casting billet surface images, and then acquires the optimum articulation through focus window square gradient algorithm. By recognizing and calculating target’s area loss rate, target area parameter evaluation can be done. The global optimum image quality point is achieved. The algorithm is effective in selecting focus plane and shutter time during hot continuous casting surface imaging process and is of a good practical value. At the same time, the algorithm is useful for image collecting work in other machine vision engineering.     

六堡茶感官质量缺陷及其成因分析

分析六堡茶的感官质量缺陷和原因,指导产品质量的提高,让消费者辨别六堡茶感官质量的优劣.方法:通过对六堡茶的初制厂实地调查和分析、对精制厂生产进行长期观察和比较、对进行不同的六堡茶进行感官审评和理化分析、文献调研等方法进行研究和分析.结果:所有感官质量缺陷均有对应的一个或多个原因造成,或者一个原因导致多个质量缺陷.结论:...     

农药标签与农药产品警示缺陷的侵权责任——从裁判文书看我国司法对农药标签的认知

农药标签记载标明农药产品的性质、特点等基本属性,是传递农药使用技术服务信息、指导农药经营者正确经营的不可替代的途径,也是农药产品警示缺陷的重要构成要件。本文以宝带苄嘧·异丙隆(草大帅)案、永农杀扑磷(融蚧)案和仙隆百草枯案等3起经省高级法院再审裁定或指定再审的裁判文书为例,对农药标签与农药产品警示缺陷的侵权责任进行探讨,提出了农药产品警示缺陷责任的认定、归责与损害赔偿的判断思路,对完善我国农药标签管理提出了建议,对解决农药纠纷也具有参考意义。     

日光温室热工缺陷面积热红外图像测量方法

隔热层和气密性缺陷是日光温室保温蓄热性能差的重要因素,为了快速检测日光温室热工缺陷区域及测量该区域的面积,该文借助热红外成像仪和Lab VIEW软件平台,构建了基于热红外图像的日光温室热工区域面积测量方法。以陕西杨凌西北农林科技大学园艺场日光温室北墙风口为测试对象,通过现场实测数据与理论计算结果进行比较分析。首先,利用热红外成像仪实时检测出日光温室北墙通风口表面与墙体内表面存在的明显温度差异,其最大温差高达8.4℃。基于温度差异,能快速找出温室内围护结构不同位置所存在的明显散热区域。然后通过直方图法、均方根法和人工提取法分别计算了散热区域面积,其中直方图面积测量方法具有较好的效果,平均相对误差为5.4%;人工提取法次之,平均相对误差为6.0%,均方根法最大,平均相对误差为11.8%。研究结果表明,基于热红外图像的直方图面积测量方法能快速检测出热工缺陷区域的面积,为进一步自动定量分析整个日光温室热工缺陷区域的面积及散热量提供了理论方法,在温室围护结构热工损耗计算方面具有较大地应用潜力,可为农民和企业提出日光温室优化改造建议。     

干燥室内锯材摆放位置对干燥缺陷的影响

本文就小径柞木锯材在顶风机式干燥室内的摆放位置对锯材干燥缺陷的影响进行了分析。结果表明：锯材在干燥室内前后不同位置时，各项可见干燥缺陷无显著性差异；上下不同位置锯材的横弯和顺弯有显著差异，材堆上部锯材弯曲较大；相关分析显示，木材的弯曲和上下摆放位置的相关性在a=0．05的水平上是显著的，说明锯材上下位置不正确的摆放会增大干燥缺陷，尤其是增大锯材的弯曲，引起锯材降等。     

木材缺陷无损检测技术研究现状

对微波法、超声波法、X射线法、核磁共振法及声学法等目前国内外木材缺陷无损检测方法的研究现状及这些检测方法的优缺点进行了阐述,同时介绍了几种便携式木材缺陷检测仪器。     

Repair of sinocutaneous fistulae in two horses

Chronic facial defects extending into the sinuses of two mares were repaired using periosteal flaps. Partial osseous bridging was established over the defects following repair. Previous attempts to close the defects with skin alone had failed. A periosteal flap is a simple surgical technique that provides the foundations for successful repair, despite the chronicity of some fistulae.     

T型刚构桥的病害分析与加固设计

针对T型刚构桥存在的悬臂端严重下挠、横隔板出现裂缝及桥面铺装破损严重等病害,在静载试验的基础上,分析病害的成因并提出体外预应力加固设计方案,以恢复桥梁线型,改善行车条件,提高结构的耐久性。理论分析表明,采用体外预应力技术对T型刚构桥进行加固后,桥梁在正常使用极限状态及承载能力极限状态的各项技术指标均满足规范要求,达到预期加固效果。     

木质材料缺陷无损检测主要研究进展

从基于成像技术、信号传播速度变化、人工模拟缺陷和信号处理的木质材料缺陷无损检测以及木质材料缺陷对其力学性能的影响5个方面论述了木质材料缺陷无损检测的研究进展, 简要分析了目前研究中存在的主要问题及其发展趋势。