基于红外复合光学原理的SF6气体分解产物现场检测方法

为最大化屏蔽光学信号对气体浓度的影响,获得高浓度的SF₆气体分解产物,提出基于红外复合光学原理的SF₆气体分解产物现场检测方法。选择适宜的复合性光学材料,在初始应用结构的作用下,求取具体的红外成像参数,完成对红外复合光学原理作用方法的初步分析。按需设置微流红外气体传感器,根据SF₆分子谱线的分布形式实施对异常峰值的剔除处理,实现基于红外复合光学原理的SF₆气体分解产物现场检测方法的设计。对比实验结果表明,在满足红外复合光学原理作用条件的情况下,光学信号不会对气体浓度产生明显影响,这对于获取高浓度的SF₆气体分解产物能够起到促进性影响作用。     

集中式红外SF6气体检测装置及其测量模型

本文提出了一种集中式红外SF6气体检测装置,该装置采用定时循环轮流选通的方式实现2路以上的变电站现场监测点气体采样检测,并采用了单光源双波长光路结构的红外SF6气体采样检测气室。因此有效地降低了制造、安装、调试、维护成本。通过求取每路红外探测信号在光源周期性开关两种状态下的差值和求取这两个差值的比值,降低了温度信号、背景光信号、光源波动等因素的影响。然后在朗伯-比尔定律的基础上,用求取的比值推导求得该检测装置的线性测量模型,最后采用最小二乘法对测量模型进行了标定,从而提高了SF6气体浓度测量的准确性和稳定性。     

SF6气体泄漏红外成像检测的技术分析和应用探讨

本文阐述了SF₆气体泄漏红外成像技术原理,总结了检测工作相关的技术标准,结合技术原理对检测工作中的影响因素进行了重点分析,并提出了相应对策,通过技术比较分析了SF₆气体泄漏红外成像的技术特点,据此提出了技术应用的策略,以更好地开展SF₆气体泄漏红外成像检测,提高开关、互感器、套管、变压器等SF₆气体绝缘设备缺陷巡检质量。     

2250kV半柔软型SF6绝缘高压脉冲传输线的研制

为了传输高压脉冲,设计了半柔软型SF6压缩气体绝缘高压脉冲传输线。根据使用要求,该传输线采用了SF6压缩气体作为绝缘,聚苯醚(PPO)绝缘垫片作为内外导体之间的支撑结构,同时内外导体均采用轧纹结构大大提高了传输线的柔软性。为实际工程使用安全性考虑,传输线外层设计了不锈钢丝铠装结构作为抗拉元件。试验结果表明,该传输线可承受的峰值电压高达到2 250kV,衰减系数为0.016dB/m,截止频率为625MHz,各项性能指标均满足要求,可用于传输高压纳秒脉冲信号。     

基于三直方图均衡的SF6红外图像对比度增强方法

电力设备SF₆泄漏气体红外图像容易淹没在背景中,肉眼难以辨识低对比度图像中泄漏气体情况,给电力设备检修带来了困扰。提出了基于三直方图均衡的SF₆红外图像对比度增强方法。首先,利用三样条插值拟合图像直方图得到二阶连续曲线,计算每个灰度级对应的一阶导数绝对值。其次,根据一阶导数绝对值和直方图分布划分直方图为两个波峰和一个相对平坦的波谷区域;最后,根据波峰和波谷将直方图分为3个子图,对3个子图分别进行直方图均衡后合并为增强图像。为了验证算法有效性,对现场拍摄的电力设备SF₆泄漏低对比度红外视频流进行增强,并与CLAHE和双直方图均衡算法进行对比。实验结果表明：本文方法在提升图像的整体对比度同时增强了泄漏气体与周围图像的对比度,提升泄漏气体红外图像视觉效果,相比于CLAHE和双直方图均衡方法,本文获得的峰值信噪比和均方根对比度值更高,增强后的图像质量更好。     

高压变电站室内SF6浓度的红外激光吸收检测方法研究

为了实现高压变电站室内SF6气体浓度的精确实时检测,对红外激光吸收方法用于SF6检测进行了研究和分析.根据SF6气体在红外波段(10.55 μm)的强吸收特性,研究了在该波段下SF6吸收特性和其浓度之间的关系,并得出了二者之间的关系曲线.该方法为高压变电站室内SF6气体的定量检测提供了理论基础.     

SF6气体湿度检测结果的影响因素分析

对于SF6电气设备之中SF6气体湿度含量的检测,能够影响电气设备的稳定安全运转与使用寿命,因此,检测SF6气体湿度含量为重中之重。本文研究了SF6气体湿度检测结果的影响因素,从压力、温度、气体流量与检测管路中的水汽与粉尘四个方面展开分析,并进一步探讨了针对上述影响因素的解决策略,旨在确保SF6气体湿度检测结果更具准确性...     

利用仿真技术从红外光谱中反演污染气体浓度的研究

;作为一种有效的大气污染气体遥感探测识别手段,傅里叶变换红外光谱仪已经得到越来越广泛的应用.当污染气体与背景存在温差时,红外光谱就能反映出污染气体的吸收或发射特征.目前,已有越来越多的人利用被动式傅里叶变换红外光谱仪进行大气污染气体的探测识别研究,而且也发展了许多由光谱提取目标信号的算法,但是这些方法大多是仅针对污染气体的定性研究的.利用仿真方法可以快速简便地计算出污染气体的浓度程长积,并可实现对遥感红外光谱的定量分析,且误差较小.     

氦离子检测器在微量SF6分解产物浓度检测中的应用分析

在SF6电气设备发生故障时,会导致SF6分解,产生气体分解产物,可以利用对SF6分解产物浓度的检测,来诊断SF6电气设备故障。虽然检测SF6分解产物浓度的方法有多种,但要实现对微量SF6分解产物准确检测非常困难,本文阐述氦离子检测器在微量SF6分解产物检测方面的应用。     

红外光谱技术在气体检测中的应用

根据气体在红外光谱区的吸收,可以采用红外光谱来检测气体的浓度.本文介绍了红外光谱技术在气体浓度检测方面的应用情况以及国外的研究进展.以甲烷和一氧化碳气体为例,描述了用红外半导体激光器或发光二极管结合红外光谱技术实现的气体探测系统.最后介绍了几种气体传感系统的实例.     

Effects of microstructure geometry and plasma modification on wetting properties of SU-8 surfaces

We describe the wetting properties of various geometric microstructures fabricated with SU-8 (negative photosensitive epoxy resin) and the effects of chemical modification by SF₆ plasma irradiation. Contact angles of water droplets were measured on ten types of microstructures such as circular pillar, square pillar, cross pillar, and mesh pattern fabricated on SU-8 layers. Moreover, these patterned surfaces were chemically modified by fluorine radicals to change their wetting properties. Contours of the water droplets were also examined from not only the side view but also from the bottom view, through the reverse side of the glass substrate, to investigate the wetting properties. Results revealed that the contact angles on the SU-8 surfaces with microstructures increased after SF₆ plasma irradiation because of C-F bond induction. Only in the mesh patterns, which have isolated cavities, the contact angles less increased as a result of the irradiation, in spite of the fact that the wetting state changed from the Wenzel mode to the Cassie-Baxter mode.     

Effect of a surface pre-treatment on graphene growth using a SiC substrate

This study reports surface pre-treatment techniques for the formation of a high-quality graphene layer on a SiC surface. It is demonstrated that silicon passivation of SiC surface using a silane flow and subsequent sacrificial oxidation can significantly improve the surface condition of a graphene layer on SiC by ensuring much fewer carbon dumps and wrinkles, reducing the electrical resistance, and providing smoother surface roughness and a larger domain size. The effect of in situ cleaning by a SF₆ treatment before graphitization was also studied. It was found that in situ cleaning using SF₆ gas can be a simple and effective means of improving the quality of a graphene layer grown on SiC. The results of this study suggest that a surface treatment before graphitization is the key to synthesize high-quality epitaxial graphene layer.     

Effects of Ar and O2 additives on photopatternable sol-gel etching in an SF6-based plasma for planar lightwave circuit fabrication

We present a novel study of the interaction of SF₆-based plasmas with sol-gel materials in a parallel plate reactive ion etching (RIE) system. The purpose of these experiments was to obtain quantitative measures and optimisation of the RIE parameters, which can be used in the microfabrication of planar lightwave circuit (PLC) devices. The sulfur hexafluoride chemistry is chosen due to its excellent etching properties of SiO₂, which is one of the components of the photopatternable sol-gel materials and is not present in typical photoresist materials. Fast process etching rate and good selectivity is achieved by varying SF₆ flow and power delivered to the electrodes. The study also reveals a marginal influence of oxygen and argon flow on the character of the sol-gel etching. The experimental data obtained can be used as a reference for any sol-gel devices fabricated using widely available RIE reactors.     

二氧化碳气体高温红外辐射的测量与研究

在高频等离子体风洞中建立了高温二氧化碳流场,通过测量和计算获得了温度和摩尔比数分布,同时进行了红外光谱测量实验。给出了测量实验装置、原理及方法,并在1500 K～3000 K范围内四个不同的温度环境下进行实验,获得了二氧化碳在不同温度下4.3 μm附近v₃振动带的红外光谱数据。发现随着温度的升高,光谱曲线的最高峰位置向长波方向移动。通过理论分析得到了高温下二氧化碳气体红外辐射实验测量中出现“红移”现象的理论原因,以及与天体物理中红移现象的区别。该理论可应用于高温气体温度测量。     

不同光栅常数下同心长波红外成像光谱仪对比

为对比分析不同光栅常数下Offner光栅和Dyson光栅光谱仪的性能差异,推导了两种光谱仪结构的衍射角公式,获得其衍射特点,并在F数为2.5,工作波段为8～12 m,光谱分辨率15.6 nm,光栅常数分别为100 m、50 m下,借助ZEMAX软件对这两种结构进行了优化设计。结果表明：较大光栅常数下,两者都能理想成像,Offner光谱仪体积约为Dyson的7倍,质量约为Dyson的1/13;较小光栅常数下,Dyson光谱仪仍可理想成像,而Offner必须加入二次非球面镜并进行离轴,才能满足系统对像质及光谱分辨率的要求,此时,Offner光谱仪体积约为Dyson的7倍,重量约为Dyson的1/11。设计结果表明,两种同心结构在加工难易度、体积、重量方面各有优劣,在光谱仪选型工作中,可根据具体情况进行取舍。     

SOI planar photonic crystal fabrication: Etching through SiO2/Si/SiO2 layer systems using fluorocarbon plasmas

Dry plasma etching of sub-micron structures in a SiO₂/Si/SiO₂ layer system using Cr as a mask was performed in a fluorocarbon plasma. It was determined that the best anisotropy could be achieved in the most electropositive plasma. A gas composition yielding the desired SOI planar photonic crystal structures was optimized from the available process gases, Ar, He, O₂, SF₆, CF₄, c-C₄F₈, CHF₃, using DC bias data sets. Application of the c-C₄F₈/(noble gas) chemistry allowed fabrication of the desired SOI planar photonic crystal. The average etching rates for the pores and ridge waveguide regions were about 71 and 97 nm/min, respectively, while the average SiO₂/Si/SiO₂ to Cr etching selectivity for the ridge waveguide region was about 33:1 in case of the c-C₄F₈/90%Ar plasma with optimized parameters.     

欧洲人为二氧化碳排放监测CO2M卫星计划

欧空局2019年将“人为二氧化碳排放监测任务CO2M”列为哥白尼计划的Sentinel 7任务,并在前期方案设计的基础上,签订了载荷研制合同。该卫星的主要探测仪器有用于CO₂和NO₂探测的CO2I和NO2I组合光谱成像仪、多角度偏振仪MAP和三波段高空间分辨率云成像仪CLIM。基于公开文献,概述了该任务的需求以及主要光学有效载荷的性能指标需求、探测原理、结构设计和关键技术等。     

高低压电器课程教改探讨

介绍了“高低电压器”课程教学改革的实施办法和体会,其中包括教学内容、教学实践环节、教学方法和教学质量考核等四个方面。     

850 nm wavelength range nanoscale resonant optical filter fabrication using standard microelectronics techniques

The fabrication and characterization of a nanoscale resonant optical filter at wavelength around 850 nm is reported using standard C-MOS compatible microelectronics techniques. We discuss the different steps of the process and their impact on the final structure. We show that the use of these techniques gives an efficient filter on glass substrate with high transmission and a narrow bandwidth of 0.4 nm. We also demonstrate the same process on a silicon substrate for a potential integration with electronic functions.