The response of plasma parameters and energy transport in the plasma sheet to interplanetary magnetic field Bz

Science China Technological Sciences - We use 9 years data of Cluster to study the dependencies of plasma parameters and energy transport in the plasma sheet on the lasting time of...     

New progress of Double Star-Cluster joint exploration and study

The magnetic reconnection of magnetosphere and the magnetospheric space storms (including magnetospheric substorm, magnetic storm, magnetospheric particle storm) has long been one of the most challenging subjects in the solar-terrestrial physics. The reconnection mechanism and global triggering process of the magnetospheric space storms are still unclear up to now. Based on the Double Star Program (DSP) and Cluster joint measurements, we have observed the solar wind density hole, the component magnetic field reconnection in the magnetopause, the structures of magnetic storm ring current, global and multi-scale driven and triggering processes of magnetospheric substorm. In this paper we will briefly introduce these results.     

Iterative inversion of global magnetospheric information from energy neutral atom (ENA) images recorded by the TC-2/NUADU instrument

A method is presented for retrieving the magnetospheric ion distribution from Energetic Neutral Atom (ENA) measurements made by the NUADU instrument on the TC-2 spacecraft. Based on the already well-established method of constrained linear inversion, an iterance technique suitable for the low count ENA measurements has been developed which is tolerant of the noise background. By the iterance technique, it is possible for the first time to simultaneously retrieve the magnetospheric ion distribution and the exospheric neutral density, and further to recover global ENA emissions in three dimensions. The technique is applied to a representative ENA image recorded in energy channel 2 (protons: 50–81 keV) of the NUADU instrument during a major geomagnetic storm and it is, thereby, shown that the retrieval method developed provides a useful tool for extracting ion distribution information from ENA data. Supported by the National Natural Science Foundation of China (Grant No. 40674083) and Chinese National Key Laboratory research outlay (Grant No. 40523006). SMcKL acknowledges with appreciation the support of Enterprise Ireland     

The state-of-the-art of the China Seismo-Electromagnetic Satellite mission

The China Seismo-Electromagnetic Satellite (CSES) mission was proposed in 2003 and approved in 2013 after ten years’ scientific and engineering demonstrations. To meet the requirement of scientific objectives, the satellite is designed to be in a sunsynchronous orbit with an altitude of 507 km and descending node time of 14:00 LT. The CSES satellite carries 8 instruments, including search-coil magnetometer (SCM), electric field detector (EFD), high precision magnetometer (HPM), GNSS occultation receiver (GOR), plasma analyzer package (PAP), langmuir probe (LAP), high energetic particle package (HEPP) and detector (HEPD), and tri-band beacon (TBB), among which HEPD is provided by Italian Space Agency. The CSES satellite was launched successfully on February 2, 2018, and is planned to operate for 5 years. The CSES mission is the first satellite in China to measure geophysical fields, which will have a lot of application prospects in the study of seismology, geophysics, space sciences, and so on.     

The electromagnetic wave experiment for CSES mission: Search coil magnetometer

The seismic activities on the Earth can produce a disturbance of the electromagnetic field and particles in the ionosphere. The search coil magnetometer(SCM) mounted on China Seismo-Electromagnetic satellite(CSES) is designed to measure the magnetic field fluctuation of low frequency electromagnetic waves in the frequency range of 10 Hz–20 k Hz. The SCM comprises a three-axis search coil sensor mounted on a 4.5 m boom and an electronic box inside satellite module. The sampling rate of the SCM is 51.2 k Hz and the time resolution of the power spectrum density(PSD) is 2 s. The frequency resolution is 12.5 Hz.There are three operation modes: survey, detailed survey and calibration. In the survey mode, the SCM can provide a PSD in the whole frequency range of 10 Hz–20 k Hz and wave forms in the low frequency range below 2 k Hz while in the detailed survey mode the SCM can provide both PSD and wave forms in the whole frequency range of 10 Hz–20 k Hz. The sensitivity of the SCM instrument is 5.0×10~(-4) n T Hz~(-1/2) at 10 Hz, 5.0×10~(–5) n T Hz~(-1/2) at 200 Hz, 3.4×10~(-5) n T Hz~(-1/2) at 2 k Hz and 1.1×10~(-4) n T Hz~(-1/2) at 20 k Hz. The telemetry rate is ~0.85 Mbps in the survey mode and ~3.0 Mbps in the detailed survey mode. The phase difference between three axes can be made generally with a precision of less than 1.0°. The dynamic range of the SCM instrument is over 100 d B. The orthogonality of three mechanical axes of search coil senor is better than 0.13°. The performance of SCM can satisfy the requirement of scientific objectives of CSES mission.     

橡胶减震支座的研究

我国是一个多地震的国家,减少地震对各种建筑物的破坏,保护人民生命财产的安全显得尤为重要。橡胶是一种良好的弹性体,它具有高阻尼性,能够吸收地震的破坏能量,减少地震对建筑物的破坏程度,用橡胶材料与钢板制造的橡胶支座具有对建     

Response of magnetic fields at geosynchronous orbit and on the ground to the sudden changes of IMF B Z

The rapid change in the Earth’s magnetosphere caused by solar wind disturbances has been an important part of the solar wind-magnetosphere interaction.However most of the previous studies focused on the perturbation of the Earth’s magnetic field caused by solar wind dynamic pressure changes.In this paper,we studied the response of geosynchronous magnetic field and the magnetic field to the rapid southward turning of interplanetary magnetic field during the interval 1350 1420 UT on 7May 2007.During this event,BZ component of the interplanetary magnetic field decreased from 15 nT to 10 nT within 3 min(1403 1406 UT).The geosynchronous magnetic field measured by three geosynchronous satellites(GOES 10 12)first increased and then decreased.The variations of magnetic field strength in the morning sector(9 10 LT)were much larger than those in the dawn sector(5 LT).Meanwhile,the H components of geomagnetic field on the ground have similar response features but exhibit latitude and LT dependent variations.Compared with H components,the D components do not have regular variations.Although the solar wind dynamical pressure encounters small variations,the magnetic field both in space and on the ground does not display similar variations.Therefore,the increase of geomagnetic field in the dawn sector is caused by the southward turning of IMF(interplanetary magnetic field)BZ.These results will help to better understand the coupling process of geomagnetic filed and interplanetary magnetic field.     

浅谈医院办公自动化

随着医院信息化程度的不断加大，医院办公自动化，“无纸化”程度也不断得到加强；本文介绍了在新形势下，开展办公自动化的有效前提，以及开展办公自动化给医院带来的经济效益和社会效益。     

Preface

正Earthquakes,which cause extreme loss of lives and properties,are the most devastating natural disasters on Earth.Scientists have since sought for ways to predict the occurrence of earthquakes and to mitigate its effects.Unfortunately,there is still no effective method for precise predictions.However,among the possible methods for short-term earthquake predictions,one of the most promising is the monitoring of electromagnetic and particle disturbances in the ionosphere,which is based on the theory that couplings exist between the lithosphere and ionosphere.     

海岸换流站设计潮位和波浪的重现期标准分析

海岸换流站目前尚无明确的防潮防浪设防标准,尤其是换流站设计潮位、设计波浪的重现期标准尚无针对性的规程规范和研究资料可查,无疑将给防潮防浪的工程设施建设带来一定的工程风险。以舟山多端柔性直流换流站为例,在分析国内外关于海堤的潮、浪设防标准基础上,结合现行核能发电厂、火力发电厂、港口等行业领域关于潮、浪的设计重现期标准,探讨了海岸换流站设计潮位和设计波浪的重现期标准,提出了100年一遇高潮位叠加50年一遇波浪的设计标准组合。