Ionospheric absorption at Zhongshan Station, Antarctica during magnetic storms in early May, 1998

In the paper the high latitude ionospheric absorption events, monitored by an imaging riometer at Zhongshan Station, Antarctica, are examined during magnetic storms in early May, 1998. The storm absorption at ~0639 UT on May 2 was mainly an equatorward progressing absorption event, which were associated with a strong negative bay of the magnetic H component and with a large Pc3 range pulsation. There was a time lag of about 1. 5 hours between the onset of the ionospheric disturbance and the IMF southward turning in the solar wind. The event at 2222 UT on May 2 was a typical midnight absorption spike event. The absorption region took the form of an elongated strip with the length of 100 - 150 km and the width of 30 - 40 km. The absorption during 0830 - 1200 UT on May 6 was a polar cap absorption (PCA) event,caused by intense precipitation of high-energy protons erupted after a large solar flare explosion.

Results of Geomagnetic Studies on the Problem of Forecasting Strong Earthquakes in Uzbekistan

The article is devoted to the problem of forecasting strong earthquakes by the geomagnetic method. The geomagnetic method is widely used on this problem in seismically active regions of the world as one of the promising, informative and operational geophysical methods. The results of long-term geomagnetic studies on the problem of forecasting strong earthquakes in Uzbekistan are presented. Geomagnetic studies were carried out on the territories of the Tashkent, Ferghana, and Kyzylkum geodynamic polygons in the epicentral zones of strong earthquakes that occurred. Long-term, medium- and short-term precursors of earthquakes have been identified. Anomalous changes in the geomagnetic field associated with the decline in aftershock activity were also revealed. The dependence between the duration of the manifestation of long-term magnetic precursors and the magnitude of earthquakes is determined. Absolute proton magnetometers MMP-1, MV-01 (Russia), and G-856 (USA) were used to measure the geomagnetic field.

Day-to-Day Variability of H Component of Geomagnetic Field in Central African Sector Provided by Yaoundé-Cameroon Amber Station

The geomagnetic data obtained from Amber Network station in Cameroon have been used for this study. The variability of H component of geomagnetic field has been examined by using geomagnetic field data of X and Y components recorded at AMBER magnetometer station hosted by the Department of Physics of University of Yaoundé (3.87°N, 11.52°E). The day-to-day variability of the horizontal intensity of the geomagnetic field was examined and shows that the scattering of H component of magnetic field variation is more on disturbed than that on quiet condition. The signatures H of geomagnetic Sq and Sd variations in intensities in the geomagnetic element, has been studied. This study shows that the daytime variations in intensities of geomagnetic elements H, Sq(H) and Sd(H) respectively are generally greater than night-time ones. This paper interests answering the two questions: 1) how can geomagnetic variations be used to study the equatorial ionosphere electrodynamics and electrojet equatorial over Africa in general and Cameroon in particular? 2) How can geomagnetic variations be used to monitor and predict space weather events in Cameroon? This paper presents and interprets the results of H component of geomagnetic field variations during magnetic storms and on quiet days.

Alpha Magnetic Spectrometer (AMS02) experiment on the International Space Station (ISS)

The Alpha Magnetic Spectrometer experiment is realized in two phases. A precursor flight (STS-91)with a reduced experimental configuration (AMS01) has successfully flown on space shuttle Discovery in June 1998.The final version (AMS02) will be installed on the International Space Station (ISS) as an independent module inearly 2006 for an operational period of three years. The main scientific objectives of AMS02 include the searches forthe antimatter and dark matter in cosmic rays. In this work we will discuss the experimental details as well as the im-proved physics capabilities of AMS02 on ISS.

直流受端馈入站与近区风电场系统振荡特性分析

随着高压直流输电工程的不断投产,以及风电项目的增多,越来越多的风电场出现在电网换相换流器高压直流输电(line-commutated-converter based high voltage direct current,LCC-HVDC)受端换流站近区,两者构成的系统存在振荡风险。为此,该文针对直流受端馈入站与近区风电场系统的振荡特性展开研究。首先,建立并验证系统的状态空间模型,基于该模型计算出系统特征值,确定LCC-HVDC与风电场共同参与的振荡主导模式并进行参与因子分析。进一步地,通过对比是否接入LCC-HVDC的主导模式,得到LCC-HVDC的接入会削弱系统阻尼的结论。最后,从系统额定容量、交流系统短路比、风电场并网线路长度等方面探究系统稳定性的影响因素,并分析系统的不同短路比、潮流比对风机网侧换流器(grid-side converter,GSC)外环控制和换流站定电流控制器性能的影响。

基于改进蜉蝣优化算法的机器人磁定位方法

针对现有物流机器人自主导航停车充电方案在远距离时停车定位精度差,造成自动回充模式下移动机器人无法对准充电桩的难题,提出一种基于改进蜉蝣优化算法(MA-LM)的物流机器人停车定位方法。本文方法将多个磁传感器阵列的磁钉定位数据融合,提高物流机器人停车定位的定位精度和定向精度。为了量化评估磁钉定位的提升效果,本文方法使用9个磁传感器组成的传感器阵列和两轮差速移动机器人在充电桩场景测试。相较于遗传优化算法和粒子群优化算法,本文提出的MA-LM算法的定位精度具有优势,在停车定位环节使用MA-LM算法的物流机器人达到定位精度±1.65 mm和定向精度0.9°。

MBR膜处理对生活垃圾中转站废水处理效果的分析

采用MBR膜生物技术处理生活垃圾中转站废水,在进水COD、NH_(3)-N、SS、TP分别为550~1100 mg/L、24~39 mg/L、25~66 mg/L、5.6~1.1 mg/L的情况下,处理后出水COD、NH_(3)-N、SS、TP去除率最高分别可达到94.5%、98.8%、86.4%、97.9%,其中悬浮物处理效果较差,最低只有48%。因此,本文从进水pH对悬浮物去除率影响做出分析,数据表明进水pH值与悬浮物SS去除率大致呈负相关关系,当pH值为5.8时,悬浮物SS去除率最高,随着pH增加至中性,悬浮物去除率逐渐降低。

大型制冷站调试中的关键问题及解决方案

制冷站是现代工业生产中不可或缺的设备之一,其主要设备制冷机压缩机采用磁浮轴承进行压缩气态氟利昂,具有高效、节能、安全等优点。本文主要围绕沙特红海公共事业和基础设施PPP项目制冷站调试过程中遇到的关键问题展开研究,并提出相应的解决方案。通过对实际案例分析,总结了制冷站调试过程中的典型问题及其解决方法,旨在为制冷站调试工程师提供参考和借鉴。

电气化铁路对NDB导航台站的电磁干扰分析

依据相关标准,基于理论分析,借助WRAP软件,完成电气化铁路对中波导航台站(NDB)的无源电磁干扰和有源电磁干扰分析。所述方法具有一定的通用性,且是机场建设可行性分析报告的重要组成部分。

巡检机器人伺服控制永磁同步电机初始位置辨识方法

针对定位法识别永磁同步电机转子初始位置误差大,影响伺服控制对永磁同步电机的控制精度,导致变电站巡检机器人定位偏差大的问题,提出一种基于最大电流法的转子初始位置辨识方法,并应用到变电站巡检机器人伺服控制系统。以巡检机器人为测试对象,验证提出辨识方法的控制精度。测试结果显示,最大电流法的误差绝对值小于5电角度,能有效解决永磁同步电机堵转、失步和超步问题,具有较好的稳定性和可靠性。

Seasonal characteristics of F region in lower solar activity period at Zhongshan Station, Antarctica

Based on data of Digisonde Portable Sounder-4 (DPS-4 ) in 1995 -1997. we have analyzed the seasonal variations of F region at Zhongshan Station (69. 4°S,76. 4°E ). During the summer of Zhongshan Station, F region ionization is mainly controlled by the solar ultraviolet radiation. Similar to the phenomena in mid-latitude area, the value f0F2 is changed with local time. During equinox scasons, soft electron precipitation from the cusp/cleft region seems significant, f0F2 is changed with rnagnetic local time, and shows the magnetic noon phenomenon. In winter. the effect of the solar radiation on the F region is less than that of summer. Instead, F region is affected by particle precipitation from cusp/cleft region as well as polar plasma convection, there fore, the diurnal variation of f0F2 is more complex and shows two peaks. F region occurs all day in summer. and seldom appears at midnight in equinox.In winter, F region shows two minimums, one is at midnight and the other is at afternoon cusp. Further analysis of the F region spread indicates that in winter the aurora oval passes over the Zhongshan Station is at 1100 UT - 1500 UT.

Simultaneous observations of Syowa East HF radar and Zhongshan Station optical aurora associated with the solar wind negative pressure impulse

The field of views of the Syowa East HF radar covers over Zhongshan Station (magnetic latitude ~ 74. 5°S). We examined the relation between HF radar signatures and optical aurora by using the data obtained on 3 Augusl 1997. A geomagnetic negative sudden impulse (SI- ) occurred at ~ 1432 UT on 3 August 1997associated with the sudden decrease of solar wind plasma density. From the behavior of the optical aurora observed by all-sky TV camera and scanning photometers at Zhongshan Station, a sudden enhancement of auroral emission intensity and poleward moving signature occurred associated with the negative SI. It is intcresting that the temporal and spatial variations of the HF radar backscatter power showed one to one correlations with optical aurora data. The details of this event are examined and compared with the data onboard WIND sate1lite and from ground based magnetometers.

Mean ionospheric properties in winter at Zhongshan Station,Antarctica

Ionograms taken from a Digisonde Portable Sounder (DPS 4) at Zhongshan Station of Antarctica in 1995 are used to analyse the mean ionospheric properties in winter. The F region is rather unstable in winter and has large diurnal variation. The monthly medium value of f oF 2 has a main peak around 0900UT when maximum value occurs and a sub peak between 1300 1500UT. It may be affected synthetically by the low energy electron precipitation in cusp region, the high latitude plasma convection and the solar radiation, resulted in so called F region magnetic noon phenomena. Low values of f oF 2 occur in post midnight (2000 0100UT) when Zhongshan Station crosses the ionospheric polar hole. Sporadic E layer which caused mostly by auroral particle precipitation can be observed almost every day with the highest value of f oE s around 1700UT. The diurnal variation of E layer is relatively smooth.

±500kV换流站工频电磁环境测量与实验室模拟

换流站内复杂电磁环境会对电力设备在线监测装置测量结果产生不利影响,为了提高装置测量结果的稳定性和可靠性,有必要对换流站设备附近区域的电磁场进行测量并分析其分布规律。文中利用电磁场分析仪对4所±500 kV换流站变压器、高抗、避雷器、电压互感器等附近的工频电场、磁场进行了测量。测量结果表明:所有被测换流站75%以上测点的电场强度分布在0~15 k V/m,最大值出现在避雷器附近,为32.6 kV/m;约90%测点的磁感应强度分布在0~80μT,最大值出现在换流变附近,为0.26 mT。基于实测结果,在实验室内搭建了工频电磁场模拟平台,该平台可同时产生连续可调的电场与磁场,且频率、方向、场强范围均满足模拟换流站现场工频电磁场的需求。文中的研究可以为变电站电磁环境测量、实验室模拟现场电磁环境工况提供参考。

基于智能手机内置传感器的地铁车站级定位

地铁运客高峰期,大众用户往往因无法在嘈杂的环境中听清语音播报到站信息而导致无法及时地做好下车准备。针对这一需求,提出了一种基于智能手机内置传感器的地铁车站级定位方法。该方法利用惯性传感器与磁力计的观测值以及解算出的水平姿态角来构建地铁车站间的指纹库,然后在实时定位时使用用户智能手机传感器观测值与指纹库进行匹配,从而确定用户即将到达的地铁站。实测结果表明,所提出的算法利用智能手机内置传感器能够实现可靠的地铁车站级定位,准确率达到98.4%。

多技术交叉融合的拟建机场测量方法研究

传统全野外数字化测图进行遮蔽角测量,存在制图周期长、工作量大,且无法满足拟建机场遮蔽角测量需求。本文以某民用机场初步设计勘查项目为例,将无人机倾斜摄影测量、超站仪无控制点测量和基于EPS三维测图系统等多技术交叉融合运用,结合优化后的内业分析工具和外业调查模式构建了一套适用于新建机场拟建导航台的场地环境调查测绘的方法,同时对各测量环节的成果精度进行了验证。结果表明:(1)无人机倾斜摄影测量技术获得三维模型精度满足地形测量精度要求;(2)多种技术交叉融合的方式不仅保证了勘查成果的质量,而且有效提高了工作效率;(3)优化后的内业数据处理和外业调查模式省时省力。本文采用的多种技术交叉融合方法,测定的障碍物遮蔽角成果可靠性高,可作为障碍物的限制高度评估、较大障碍物及时拆除和机场正式建设的基础数据。

地铁车站磁悬浮直膨式空调机组性能实测研究

地铁车站磁悬浮直膨式空调机组的性能研究过去多停留在实验室或工程样机阶段,由于现场施工安装、调试等因素的影响,现场实际安装的机组性能与样机可能存在一定的差异。本文选取洛阳地铁已经投入运行的4台磁悬浮直膨式空调机组,对其实际运行性能进行了测试分析。实测结果表明:磁悬浮直膨式空调机组在100%、75%负荷工况下的现场实测性能与实验室测试性能一致,但在50%负荷工况下有一半机组的实测性能比实验室测试性能低21%~38%,需要重视低负荷工况下运行参数的调试工作;机组可以通过改变送风量、送风温度设定值等参数灵活调节制冷量;在洛阳地铁车站长时间运行负荷工况40%~80%区间内的实测机组制冷性能系数达到7.4~12.0,部分负荷性能较好,可以很好地适应地铁车站长期处于运营初/近期的低客流、低空调负荷的情况。

融合DBSCAN多测点算法的磁方位校正

单测点校正法计算复杂、不稳定、误差较大,无法满足井下地磁方位角的精度要求。基于间接单测点分析法和Brooks多测点分析法,提出一种新方法,通过DBSCAN(Density-Based Spatial Clustering of Applications with Noise)算法识别并剔除噪声,采用椭圆校正法校正径向干扰,轴向干扰则由单轴多测点分析法校正。实验证明:改进多测点法不仅可以进一步提高椭圆校正的拟合效果,还能降低噪声对参考点计算值的影响,计算得到的方差曲线收敛性更强、更稳定,校正后方位角误差进一步降低。

RPIR+磁混凝沉淀在深圳市白花河沿岸黑臭水体治理中的应用

为解决深圳市白花河沿岸初期雨水和污水长期直排导致河道黑臭的问题,基于“RPIR+磁混凝沉淀”技术,采用上、下合建的方式,在白花河沿岸新建1座有效容积为2×10^(4)m^(3)的调蓄池及处理能力为1.5×10^(4)m^(3)/d的污水处理站,实现初期雨水和污水就地处理、就近补水。运行结果表明,该污水处理系统对白花片区初期雨水和污水具有较好的处理能力,各项出水指标均优于考核标准并达到了地表IV类水标准,具有节省用地、施工周期短、投资成本低、出水稳定等优点,有效地改善了白花河河道黑臭现状,可为其他类似黑臭水体治理项目提供参考。

多台站地磁日变观测数据对远海磁测精度的影响分析

用广东肇庆、海南琼中和一个设在西沙海域的海底地磁日变观测站三个台站的地磁观测数据,对西沙东南部海域某工区的海洋磁测数据进行日变改正的处理,研究不同距离的日变观测数据对远海区磁测改正精度的影响程度,并且尝试探讨用多台站磁日变校正方法来提高远海区的地磁精度的技术方法。