Analysis of Excitation Characteristics of Ultra High Frequency Electromagnetic Waves Induced by PD in GIS

The understanding of the excitation mechanism of ultra high frequency (UHF) electromagnetic waves (EW) is essential for ap- plying UHF method to partial discharge (PD) detection. Since the EW induced by PD in gas insulated switchgear (GIS) contains not only transverse electromagnetic (TEM) wave, but also high-order transverse electric (TE) and high-order transverse magnetic (TM) waves, we analyzed the proportions between the TEM wave and the high order waves, as well as the influence of the PD position on this proportion, using the finite different time domain (FDTD) method. According to the unique characteristics of the waves, they are separated only ap- proximately. It is found that the high-order mode is the main component, more than 70%, of the electric field around the enclosure of GIS, and that with the increasing distance between PD source and inner conductors, the low frequency ( below about 800 MHz) component of EW decreases, but the high frequency component (above 1 GHz) increases, meanwhile the proportion of high-order components in EW could reach 77% from 70%. It concluded that the closer the PD source to the enclosure is, the easier high order EW may be excited.

A magnetic bald-patch flare in solar active region 11117

With SDO observations and a data-constrained magnetohydrodynamics （MHD） model, we identify a confined multi-ribbon flare that occurred on 2010 October 25 in solar active region 11117 as a magnetic bald patch （BP） flare with strong evidence. From the photospheric magnetic field observed by SDO/HMI, we find there are indeed magnetic BPs on the polarity inversion lines （PILs） which match parts of the flare ribbons. From the 3D coronal magnetic field derived from an MHD relaxation model constrained by the vector magnetograms, we find strikingly good agreement of the BP separatrix surface （BPSS） footpoints with the flare ribbons, and the BPSS itself with the hot flaring loop system. Moreover, the triggering of the BP flare can be attributed to a small flux emergence under the lobe of the BPSS, and the relevant change of coronal magnetic field through the flare is reproduced well by the pre-flare and post-flare MHD solutions, which match the corresponding pre- and post-flare AIA observations, respectively. Our work contributes to the study of non-typical flares that constitute the majority of solar flares but which cannot be explained by the standard flare model.

Preprocessing photospheric vector magnetograms for nonlinear force-free field extrapolation of the global corona

Nonlinear force-free magnetic field （NLFFF） extrapolation based on the observed photo- spheric magnetic field is the most important method to obtain the coronal magnetic field nowadays. However, raw photospheric magnetograms contain magnetic forces and small-scale noises, and fail to be consistent with the force-free assumption of NLFFF models. The procedure for removing the forces and noises in observed data is called preprocessing. In this paper, we extend the preprocessing code of Jiang ＆ Feng to spherical coordinates for a full sphere. We first smooth the observed data with Gaussian smoothing, and then split the smoothed magnetic field into a potential field and a non-potential field. The potential part is computed by a numerical potential field model, and the non-potential part is prepro- cessed using an optimization method to minimize the magnetic forces and magnetic torques. Applying the code to synoptic charts of the vector magnetic field from SDO/HMI, we find it can effectively reduce the noises and forces, and improve the quality of data for a better input which will be used for NLFFF extrapolations applied to the global corona.

Short-term solar flare prediction using multi-model integration method

A multi-model integration method is proposed to develop a multi-source and heterogeneous model for short-term solar flare prediction. Different prediction models are constructed on the basis of extracted predictors from a pool of observation databases. The outputs of the base models are normal- ized first because these established models extract predictors from many data resources using different prediction methods. Then weighted integration of the base models is used to develop a multi-model integrated model （MIM）. The weight set that single models assign is optimized by a genetic algorithm. Seven base models and data from Solar and Heliospheric Observatory/Michelson Doppler Imager lon- gitudinal magnetograms are used to construct the MIM, and then its performance is evaluated by cross validation. Experimental results showed that the MIM outperforms any individual model in nearly every data group, and the richer the diversity of the base models, the better the performance of the MIM. Thus, integrating more diversified models, such as an expert system, a statistical model and a physical model, will greatly improve the performance of the MIM.

Measurement of the g Factor of the 3.1232 MeV 19/2^(-) Level in ^(43)Sc by Perturbed Angular Distribution Method

The g-factor hence the magnetic moment,of the isomeric state 43Sc（|9/2-,3.1232 MeV）has been measured by the time differential perturbed angular distributionmethod.The measured values are g=0.3279（19）and μ=3.108（18）nm.

IPO-MoM混合法分析开槽电大目标的电磁散射

本文利用迭代物理光学法（ Ｉ Ｐ Ｏ） 与数值方法相结合的混合方法计算二维开槽电大目标的电磁散射．首先根据等效原理将散射场进行分解，分别采用 Ｉ Ｐ Ｏ 法和矩量法（ Ｍｏ Ｍ） 计算槽缝填充的电大目标和槽缝的散射，并在口径处应用广义网络原理处理耦合问题．数据结果表明本文方法是准确和高效的．

隧道施工时探查、预报断层、岩溶、地下水的技术新进展--将隐患变成明示，将危险消灭在发生之前

经十余年的不断努力,特别是2003年以后,由于国家有关部门的重视和支持,在探查预报隧道掌子面前方断层、破碎带、溶洞、暗河、地下水等方面有较大进展,结合探查实例,介绍以陆地声纳法为代表的弹性波系列方法、瞬变电磁法和探地雷达组合的成套方法技术,在断层的空间定位、探查地下水、探查溶洞、暗河等方面的理论研究成果和实测预报中取得的效果。

永磁同步电机匝间短路-退磁耦合故障分析

永磁同步电机存在匝间短路故障、永磁体退磁故障和偏心故障等多种故障类型,对其故障诊断的研究一直集中于单一故障,耦合故障涉及较少。以匝间短路-退磁耦合故障为例,运用有限元法分别建立电机正常条件及不同耦合故障程度的二维模型;通过瞬态磁场求解器求得空载和额定负载两种不同工况下电机在正常以及不同故障程度运行时的磁感线分布云图、转矩曲线图、相反电动势曲线图,并利用傅里叶变换对相反电动势谐波含量进行了分析。结果表明,耦合故障条件下相反电动势的三次谐波含量明显高于正常条件值,相反电动势的三次谐波含量的增加可作为判断该耦合故障的依据。

Design and calibration of a high-sensitivity and high-accuracy polarimeter based on liquid crystal variable retarders

Polarimetry plays an important role in the measurement of solar magnetic fields. We devel- oped a high-sensitivity and high-accuracy polarimeter （HHP） based on nematic liquid crystal variable retarders （LCVRs）, which has a compact setup and no mechanical moving parts. The system design and calibration methods are discussed in detail. The azimuth error of the transmission axis of the polarizer as well as the fast axes of the two LCVRs and the quarter-wave plate were determined using dedicated procedures. Linearly and circularly polarized light were employed to evaluate the performance of the HHP. The experimental results indicate that a polarimetric sensitivity of better than 5.7 × 10-3 can be achieved by using a single short-exposure image, while an accuracy on the order of 10-5 can be reached by using a large number of short-exposure images. This makes the HHP a high-performance system that can be used with a ground-based solar telescope for high-precision solar magnetic field investigations.

A Non-axisymmetric Spherical α~2-Dynamo

Using the Chebyshev-tau method, the generation of oscillatory nonaxisymmetric stellar magnetic fields by the α^2-dynamo is studied in spherical geometry. Following the boundary conditions given by Schubert ＆ Zhang, the spherical α^2-dynamo consists of a fully convective spherical shell with inner radius ri and outer radius ro. A comparison of the critical dynamo numbers of axisymmetric and φ-dependent modes for different thicknesses of the convective shell and different α- profiles leads to the following qualitative results： （i） when the angular factor of α- profile is sin^n θ cosθ （n= 1, 2, 4） the solutions of the α^2dynamo are oscillatory and non-axisymmetric, （ii） the thinner the convective shell, the more easily is the nonaxisymmetric mode excited and the higher is the latitudinal wave number, （iii） the thickness of the outer convective shell has an effect on the symmetries of the magnetic fields.

Research on New Testing Method and Instrument of Clothing Pressure

This paper discusses the formation of the fabric clothingpressure,the efforts of the human body and the impor-tance of the clothing pressure measurement.Several as-pects such as setting up the scientific and simple measur-ing method of the clothing pressure,the designing andmaking the measuring instruments are emphasized.Bymeans of experimental testing and analysis,some usefulresults can be derived from these works.

半航空频率域电磁法针对铁路勘察的研究进展

随着我国铁路网的不断扩展,在高原及艰险山区构建铁路网已成必然。然而,因地势陡峭,部分线位人员无法抵达,常导致关键勘察数据缺失。为解决这一问题,从传统地面勘察转向空中,采用地球物理技术与无人机技术相结合的半航空频率域电磁法。针对高原艰险山区长大深埋隧道的勘察需求,团队自主设计研发了半航空电磁硬件系统,通过与地面方法的同精度对比验证,其结果一致性达到90%以上。该技术成功应用于某隧道测区的勘察任务,弥补了因地势陡峭导致的勘察数据空白,有效降低了勘察成本,显著提高了工作效率,为我国铁路勘察工作提供了新的技术路径与方法。

凤亭河水库坝体渗漏检测

根据凤亭河水库大坝渗漏情况,引入物探手段查明漏水点与库水位的关系。综合高密度电法、瞬变电磁法、自然电场法、探地雷达法等现场检测渗漏情况,揭示大坝现状质量情况,初步确定渗漏范围并提出处理意见及建议,并为大坝验收工作提供技术支持。

应用矩量法计算变电站内的空间电磁场

基于矩量法,提出了一种适合于变电站内开关操作时母线、设备间连线、架空线路产生的电磁场的计算方法,可以应用于变电站内较高频率分量的电磁场计算。应用文中计算方法与给出的计算方法分别对同一算例进行计算,其计算结果均一致,验证了文中方法的有效性。最后,借助于快速傅立叶变换,应用文中计算方法对某500kV变电站开关合闸操作时空载母线上的电流波过程和空间瞬态电场分布进行了预测计算,计算结果被应用于该变电站保护小室的屏蔽设计。

无线电磁法(WEM)在地球物理勘探中的初步应用

无线电磁法（WEM）是上世纪90年代发展起来的一种新的人工源电磁探测技术，它通过一个固定大功率发射台发射0．1～300Hz超低频／极低频电磁信号来探浸ll地下地质结构．国内对WEM法的应用已做了大量的理论和实际试验工作，例如，大功率发射台辐射的电磁场计算，不同距离电磁信号发射接收试验，油田深部结构探测试验等．从试验的结果看，WEM法在提高电磁测深数据质量上具有很大的优势．

电磁层析成像灵敏度矩阵实验测试方法

灵敏度矩阵是电磁层析成像系统图像重建的先验信息,它反映了电磁层析成像系统在重建截面内微小测试单元逐个放入扰动物质后检测输出值的变化。为实现较为精细的图像重建效果,通常将截面剖分成数量较多的微小单元,用于灵敏度计算和重建结果表达,所以电磁层析成像灵敏度矩阵一般依靠电磁场有限元仿真计算正问题的方法获得。但有限元仿真的正问题模型难以与实际模型完全一致,导致图像重建的先验信息不准,从而影响重建效果。区别于传统研究方法,设计了灵敏度矩阵的实验测试方法,应用精密电动平移台驱动测试试样,使试样按照有限元软件对截面剖分的单元坐标自动逐个测试,最后应用测试结果合成重建所需灵敏度矩阵,图像重建结果证明了该方法的有效性。

输电线路任意点故障的数字仿真

本文在贝瑞隆模型基础上提出了一种能计算长线路上任意点短路的仿真方法，这种方法可以在电磁暂态仿真计算中，在任意时刻进行交直流线路中任意点故障的仿真计算且不需增加过多的计算量，同时可对冲击电流、瞬态过电压及谐波进行分析。文中给出了谐波分析结果并得出了各次谐波幅值与短路点位置的函数曲线，由此可分析谐波与故障类型及故障点之间的关系，并找出系统中产生最大谐波的短路点位置及故障类型。

永磁同步电机无位置传感器运行场路耦合分析

为精确设计基于凸极跟踪的无位置传感器控制系统,在分析高频电压信号激励下永磁同步电机数学模型的基础上,提出一种基于场路耦合法的永磁同步电机无位置传感器控制系统分析与设计新方法。该方法建立在永磁同步电机三维电磁场分析模型和基于转子磁场定向的无位置传感器控制系统模型上,通过场路耦合法进行协同仿真研究,仿真结果可精确反映无位置传感器运行性能和高频电压信号激励下永磁同步电机与控制系统的相互耦合特性。在此基础上建立了与仿真系统完全对应的实验系统,实验结果与仿真结果一致,表明该分析设计方法的正确性和可实现性。

极低频探地(WEM)工程

"极低频探地(WEM)工程"是国家发展和改革委员会批准的"十一五"国家重大科学技术基础设施建设项目之一,用于资源探测和地震预测及其他前沿科学研究。文章对工程项目背景、建设内容、关键技术和试验成果作了全面介绍,在此基础上,对工程的应用前景作了展望。

利用微波加热开采地下油页岩的技术

对目前国内外油页岩原位开采技术研究进行的分析表明,油页岩具有导热性差的特点。为了解决传统的热传导开采方法效率低、成本高的问题,提出了一种微波加热开采油页岩的新型技术。利用微波加热方式,电磁能直接作用于介质分子而转换成热能,其透射性能使物料内外介质同时受热,不需要热传导。在方案实施过程中,在油页岩层中钻羽状井并填入吸波介质,可大大改善油页岩的吸波能力,可以以较快的速度使页岩油的升温,并逐渐地将干酪根裂解转化为页岩油气。页岩油气会通过加热产生的裂缝运移到生产井,并被抽排到地面。