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Determination of ejection velocity of rock fragments during rock burst in consideration of damage 被引量:12
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作者 左宇军 李夕兵 周子龙 《Journal of Central South University of Technology》 EI 2005年第5期618-622,共5页
The ejection velocity of rock fragments during rock burst, one of the important indexes representing the rock burst strength, is used most conveniently in the supporting design of tunnel with rock burst tendency and i... The ejection velocity of rock fragments during rock burst, one of the important indexes representing the rock burst strength, is used most conveniently in the supporting design of tunnel with rock burst tendency and is often determined by means of observation devices. In order to calculate the average ejection velocity of rock fragments theoretically, the energy of rock burst was divided into damage consuming energy and kinetic energy gained by unit volume of rock firstly, and then the rock burst kinetic proportional coefficient η was brought up which could be determined according to the rock-burst damage energy index W_D , at last the expression of the average ejection velocity of rock fragments during rock burst was obtained and one deep level underground tunnel was researched using the mentioned method. The results show that the calculation method is valid with or without considering the tectonic stress of tunnels, and that the method can be a reference for supporting design of deep mining. 展开更多
关键词 rock burst ejection velocity support design energy equilibrium DAMAGE
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A novel variable topology design for a multi-flexible ejection mechanism 被引量:3
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作者 Hao Liu Jun Zhou +1 位作者 Zong-lai Mo Shi-wei Zhang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2020年第2期432-438,共7页
The airborne missile launch mechanism often subjects to significant deformations induced by the large ejection force during high-speed actuations in missile ejection process,leading to a substantial deviation of separ... The airborne missile launch mechanism often subjects to significant deformations induced by the large ejection force during high-speed actuations in missile ejection process,leading to a substantial deviation of separation parameters from designed values that threats safety of the carrier.This study proposes a novel variable topology design for launch mechanism,achieved via a Prsmatic-Revolute-Revolute pair(PR-R)motion formed by the structural gap with a specific direction.It enables launch mechanism variability during missile ejection process and optimizes the ejection force given by the front and back ejection arms,and greatly optimizes the separation parameters during missile ejection.The kinetics simulation analysis is conducted under working conditions of the original ejection mechanism and the novel mechanism with variable topology design,respectively.The results show that the novel variable topology design is more befitting for the launch process in terms of system safety and controllability,effectively improving the separation posture,restraining the flexible effect of the mechanism,and fulfilling the effectiveness of the design value of multi-rigid body. 展开更多
关键词 VARIABLE TOPOLOGY Gap dynamics Multi-flexible BODY FLEXIBLE control ejection mechanism
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Biomechanical Manifestations of Diastolic and Systolic Function in Rats with Heart Failure with Preserved Ejection Fraction 被引量:1
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作者 Zhongjie Yin Wenchang Tan 《医用生物力学》 EI CAS CSCD 北大核心 2019年第A01期77-77,共1页
Objective Heart failure(HF)is divided into two types:Heart failure with reduced ejection fraction(HFrEF)and heart failure with preserved ejection fraction(HFpEF).The latter always results in diastolic dysfunction,char... Objective Heart failure(HF)is divided into two types:Heart failure with reduced ejection fraction(HFrEF)and heart failure with preserved ejection fraction(HFpEF).The latter always results in diastolic dysfunction,characterized by changes in mechanical properties.The objective of this study is to build a finite element(FE)model of HFpEF and analyze diastolic and systolic function in rats.Methods Ten Dahl salt-sensitive rats were fed either a low-salt(LS)(n=5)or highsalt(HS)(n=5)diet beginning at 7 weeks of age and scanned by ultrasonic machine at 14 weeks of age.A non-linear FE model of the left ventricle(LV)was built from cardiac echo images at end-diastole and passive material properties of the LV were prescribed using Fung’s transversely isotropic constitutive law.Fiber angles of the endocardium and epicardium were prescribed as 53°°and-52°,respectively,with respect to the circumferential direction and varied linearly through the LV wall.The method developed by Krishnamurthywas used to determine the unloaded geometry to estimate the Fung passive material parameters.LV end-diastolic pressure(EDP)was determined from the measured pressure waves and applied to the endocardium at the unloaded geometry to simulate passive filling.Active material properties of the LV were prescribed using Guccione’s time-varying elastance model and maximum isometric tension was scaled to match the measured peak systolic pressure.The finite element model was then coupled to the Windkessel model,whose parameters were adjusted to the measured hemodynamics.Results Measured LVEDPs of LS and HS rats were 4.9±3.4 mmHg and 13.2±5.4 mmHg(P-0.030 8),respectively.End-diastolic Cauchy stress along the fiber direction for LS rats was significantly lower than for HS rats(0.91±0.60 kPa vs 3.00±0.63 kPa,P=0.001 4)and there was a similar trend in end-diastolic Green Strain along the fiber direction(0.058±0.003 vs 0.072±0.010,P=0.012 8,Figure 1b),as well.There was no distinctive difference between end-systolic Cauchy stress along the fiber direction for LS rats and HS rats(17.2±4.3 kPa vs 17.2±5.5 kPa,P=0.991 9)but end-systolic Green Strain along the fiber direction for LS rats was significantly higher than for HS rats(-0. 108±0.017 vs-0.065±0.024,negative sign represents direction).Conclusions For rats with HFpEF,it is the elevated LVEDP that induces the increase in end-diastolic stress and strain,thereby leading to diastolic dysfunction.Because of the preserved ejection fraction,HFpEF has less effect on systolic function. 展开更多
关键词 BIOMECHANICAL MANIFESTATIONS Heart Failure PRESERVED ejection Fraction CAUCHY
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Application of particle trajectory model in 1D planar ejection
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作者 刘坤 柏劲松 李平 《Journal of Central South University》 SCIE EI CAS 2008年第S1期149-154,共6页
A simple one-dimensional planar model for ejection was set up based on experiments.And numerical simulation was performed on this model with particle trajectory model method.An Eulerian finite volume method was conduc... A simple one-dimensional planar model for ejection was set up based on experiments.And numerical simulation was performed on this model with particle trajectory model method.An Eulerian finite volume method was conducted to resolve gas field.And Lagrangian method was imposed to track each particle.The interaction between gas and particles was responded as source terms in governing equations which were induced by forces.The effects of total spraying mass,particle size and other factors on the mixture of particles and gas were investigated.The spatial distributions of particle mass and velocity at different time were presented.The result shows that the numerical results are qualitatively consistent to those of experiments. 展开更多
关键词 ejection PARTICLE mixture ONE-DIMENSIONAL PLANAR ejection MODEL PARTICLE trajectory MODEL particles spatial DISTRIBUTIONS
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Significance of the left ventricular ejection/filling parameters in patients with pulmonary arterial hypertension:a magnetic resonance imaging based study
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作者 Tao Yang Li Huang +6 位作者 Wen Li Yan Zhang Zhihong Liu Xinhai Ni Qing Gu Changming Xiong Jianguo He 《中国循环杂志》 CSCD 北大核心 2018年第S01期167-167,共1页
Background The goal of this study was to explore the significance of left ventricular(LV)ejection/filling parameters in assessing severity and prognosis of pulmonary arterial hypertension(PAH).Methods Newly diagnosed ... Background The goal of this study was to explore the significance of left ventricular(LV)ejection/filling parameters in assessing severity and prognosis of pulmonary arterial hypertension(PAH).Methods Newly diagnosed PAH patients were recruited between July 2011 and December 2013 prospectively.Cardiopulmonary hemodynamics derived from right heart catheterization,and LV ejection/filling parameters derived from CMR were collected.Follow-up data were collected periodically using a specifically-designed network database until April 30,2016. 展开更多
关键词 LEFT VENTRICULAR ejection/filling parameters pulmonary ARTERIAL hypertension CMR
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Experimental Research on Influence of Some Factors on Ejection Height of Cargo Projectile
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作者 郁浩 王晓天 +1 位作者 李欣 李纪敏 《Defence Technology(防务技术)》 CAS 2012年第1期16-20,共5页
Some factors influencing the cargo projectile's ejection height in different conditions were analyzed by using harmonic curve diagram and cluster method.The test results of the ejection height for a certain cargo ... Some factors influencing the cargo projectile's ejection height in different conditions were analyzed by using harmonic curve diagram and cluster method.The test results of the ejection height for a certain cargo projectile show that the wind speed and direction are the main influence factors.For given meteorological conditions,the applied environmental stress becomes the main cause,while the launching angle does not influence the ejection height. 展开更多
关键词 mathematical statistics ejection height harmonic curve diagram cluster analysis cargo projectile
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Effect of levosimendan on plasma intestinal barrier factors in heart failure patients with reduced ejection fraction
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作者 WU Youxuan HU Xiaolei +7 位作者 MAO Xiaoxiao LIU Huijun LI Shanshan ZENG Youjie XU Pingsheng XIAO Haiyan LI Dai XIA Ke 《中南大学学报(医学版)》 2025年第9期1611-1623,共13页
Objective:In addition to dyspnea and edema,gastrointestinal discomfort is common among patients with heart failure(HF).Reduced cardiac output can lead to inadequate perfusion of the intestinal mucosa and subsequent im... Objective:In addition to dyspnea and edema,gastrointestinal discomfort is common among patients with heart failure(HF).Reduced cardiac output can lead to inadequate perfusion of the intestinal mucosa and subsequent impairment of the intestinal barrier.Levosimendan,a novel inotropic agent,binds to cardiac troponin C to enhance calcium sensitivity,activates ATP-dependent potassium channels in cardiomyocytes and vascular smooth muscle cells,exerts positive inotropic and vasodilatory effects,and reduces free radical generation,thereby improving systemic hemodynamics including intestinal circulation.However,clinical evidence regarding its protective effects on the intestinal barrier in HF patients remains limited,and the underlying mechanisms require further clarification.This study aims to investigate whether levosimendan confers protective effects on the intestinal barrier in HF patients and to explore its potential mechanisms.Methods:Network pharmacology was first used to analyze potential mechanisms of levosimendan in treating intestinal barrier dysfunction among HF patients.A total of 62 hospitalized patients with acute exacerbation of HF with reduced ejection fraction(HFrEF)were enrolled based on echocardiographic left ventricular ejection fraction.According to clinical medication regimens,patients were assigned to a conventional treatment group(n=31)or a levosimendan treatment group(n=31).The conventional treatment group received standard anti-HF therapy,while the levosimendan treatment group received levosimendan in addition to standard therapy.Enzyme-linked immunosorbent assays were used to measure plasma levels and changes in the intestinal-barrier proteins zonulin,intestinal fatty acid binding protein(I-FABP),proinflammatory cytokines[interleukin(IL)-17,IL-6,and tumor necrosis factor(TNF)-α],anti-inflammatory cytokine IL-10,and N-terminal probrain natriuretic peptide(NT-proBNP).Improvements in cardiac function and gastrointestinal symptoms were evaluated using the Kansas City Cardiomyopathy Questionnaire(KCCQ)and the Gastrointestinal Symptom Rating Scale(GSRS).Results:Network pharmacology indicated that the effects of levosimendan on intestinal barrier dysfunction in HF patients may involve inflammation-related pathways such as IL-17 and TNF.Clinically,after treatment,zonulin decreased by 32.94 ng/mL in the levosimendan treatment group versus 15.05 ng/mL in the conventional treatment group(P<0.05).I-FABP decreased by 6.97 pg/mL in the levosimendan treatment group but increased by 35.16 pg/mL in the conventional treatment group(P<0.05).IL-6,IL-17,and TNF-αdecreased by 1.11 pg/mL,1.21 pg/mL,and 2.83 pg/mL,respectively,in the levosimendan treatment group,whereas they increased by 7.68 pg/mL,0.67 pg/mL,and 2.38 pg/mL in the conventional treatment group(all P<0.05).IL-10 decreased by 24.48 pg/mL in the conventional treatment group but increased by 24.98 pg/mL in the levosimendan treatment group(P<0.05).NT-proBNP increased by 7.35 pg/mL in the conventional treatment group but decreased by 4.73 pg/mL in the levosimendan treatment group(P<0.05).KCCQ scores increased by 0.36 in the conventional treatment group and 1.86 in the levosimendan treatment group,GSRS scores decreased by 1.00 in the conventional treatment group and 2.40 in the levosimendan treatment group,respectively,but the differences were not statistically significant(both P>0.05).Conclusion:Levosimendan not only improves HF and gastrointestinal symptoms in hospitalized patients with acute exacerbation of HFrEF but also reduces plasma intestinal barrier factor levels.These effects may be associated with decreased plasma proinflammatory cytokines and increased anti-inflammatory cytokines after treatment,potentially involving IL-17 and TNF signaling pathways. 展开更多
关键词 heart failure with reduced ejection fraction network pharmacology levosimendan intestinal barrier factors inflammatory cytokines
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Overview of the Solar Polar Orbit Telescope Project for Space Weather Mission 被引量:5
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作者 XIONG Ming LIU Ying +20 位作者 LIU Hao LI Baoquan ZHENG Jianhua ZHANG Cheng XIA Lidong ZHANG Hongxin RAO Wei CHEN Changya SUN Weiying WU Xia DENG Yuanyong HE Han JIANG Bo WANG Yuming WANG Chuanbing SHEN Chenglong ZHANG Haiying ZHANG Shenyi YANG Xuan SANG Peng WU Ji 《空间科学学报》 CAS CSCD 北大核心 2016年第3期245-266,共22页
The Solar Polar ORbit Telescope(SPORT) project for space weather mission has been under intensive scientific and engineering background studies since it was incorporated into the Chinese Space Science Strategic Pionee... The Solar Polar ORbit Telescope(SPORT) project for space weather mission has been under intensive scientific and engineering background studies since it was incorporated into the Chinese Space Science Strategic Pioneer Project in 2011.SPORT is designed to carry a suite of remote-sensing and in-situ instruments to observe Coronal Mass Ejections(CMEs),energetic particles,solar high-latitude magnetism,and the fast solar wind from a polar orbit around the Sun.The first extended view of the polar regions of the Sun and the ecliptic enabled by SPORT will provide a unique opportunity to study CME propagation through the inner heliosphere,and the solar high-latitude magnetism giving rise to eruptions and the fast solar wind.Coordinated observations between SPORT and other spaceborne/ground-based facilities within the International Living With a Star(ILWS) framework can significantly enhance scientific output.SPORT is now competing for official selection and implementation during China's 13 th Five-Year Plan period of 2016-2020. 展开更多
关键词 Space weather Coronal mass ejection Solar magnetism Solar wind Solar energetic particle
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Die wall lubricated warm compaction behavior of non-lubricant admixed iron powders 被引量:2
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作者 叶途明 易健宏 +3 位作者 陈仕金 彭元东 李丽娅 夏庆林 《Journal of Central South University of Technology》 2005年第6期653-656,共4页
The phenomena of die wall lubricated warm compaction of non-lubricant admixed iron powders were researched, and its mechanism of densification was discussed. Water atomized powder obtained from the Wuhan Iron and Stee... The phenomena of die wall lubricated warm compaction of non-lubricant admixed iron powders were researched, and its mechanism of densification was discussed. Water atomized powder obtained from the Wuhan Iron and Steel Corporation was used. With compacting and sintering, compared with cold compaction, the density of warm compacted samples increases by 0.07 - 0. 22 g/cm^3 at the same pressed pressure. The maximum achievable green density of warm compacted samples is 7.12 g/cm^3 at 120℃, and the maximum sintered density is 7.18 g/cm^3 at 80℃. Compared with cold compaction, the ejection force of warm compaction is smaller; the maximum discrep- ancy is about 7 kN. The warm compacted mechanism of densification of iron powders can be obtained: heating the powder contributes to improving plastic deformation of powder particles, and accelerating the mutual filling and rearrangement of powder particles. 展开更多
关键词 powder metallurgy warm compaction die wall lubrication ejection force mechanism of densification
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掌握现代科学技术 提高装帧艺术水平
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作者 王肖生 《现代出版》 1995年第2期28-28,共1页
掌握现代科学技术提高装帧艺术水平王肖生现代电脑的产生和发展,为编辑、美术设计人员提供了现代化的、先进的编辑加工、绘画创作及排版的手段。通过电脑,利用绘画专用的计算机软件,可以进行美术作品的创作和封面装帧设计。适合于绘... 掌握现代科学技术提高装帧艺术水平王肖生现代电脑的产生和发展,为编辑、美术设计人员提供了现代化的、先进的编辑加工、绘画创作及排版的手段。通过电脑,利用绘画专用的计算机软件,可以进行美术作品的创作和封面装帧设计。适合于绘画、装帧设计的计算机系统的硬件主要... 展开更多
关键词 compression ejection REFRIGERATION CYCLE COP
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Research Advances of Solar Corona and Interplanetary Physics in China: 2012–2014
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作者 ZHAO Xinhua WANG Yuming +4 位作者 YAN Yihua CHEN Yao CHENG Xin HE Jiansen QIN Gang 《空间科学学报》 CAS CSCD 北大核心 2014年第5期565-604,共40页
Solar transients and their related interplanetary counterparts have severe effects on the space environments of the Earth. Therefore, the research of solar corona and interplanetary physics has become the focus of stu... Solar transients and their related interplanetary counterparts have severe effects on the space environments of the Earth. Therefore, the research of solar corona and interplanetary physics has become the focus of study for both solar and space scientists. Considerable progress has been achieved in these aspects by the solar and space physics community of China during 2012–2014, which will be given in this report. The brief report summarizes the research advances of solar corona and interplanetary physics into the following parts: solar wind origin and turbulence, coronal waves and seismology, solar eruptions, solar energetic particle and galactic cosmic ray, magnetic reconnection,Magnetohydrodynamic(MHD) models and their applications, waves and structures in solar wind,propagation of ICMEs/shocks and their arrival time predictions. These research achievements have been achieved by Chinese solar and space scientists independently or via international collaborations. 展开更多
关键词 Solar WIND CORONAL mass ejection ENERGETIC particles INTERPLANETARY transients Space WEATHER
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Interplanetary Physics Research in China During 2004 - 2005
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作者 WANG Chi WANG Shui 《空间科学学报》 CAS CSCD 北大核心 2006年第z1期90-96,共7页
This brief report summarized the latest advances of the interplanetary physics research in China during the period of 2004-2005, made independently by Chinese space physicists and through international collaboration. ... This brief report summarized the latest advances of the interplanetary physics research in China during the period of 2004-2005, made independently by Chinese space physicists and through international collaboration. The report covers all aspects of the interplanetary physics, including theoretical studies, numerical simulation and data analysis. 展开更多
关键词 Solar WIND plasma CORONAL MASS ejection INTERPLANETARY shock Magnetic CLOUD
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Heliosphereic Physics Research in China: 2002-2003
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作者 WANG Chi FENG Xueshang WANG Shui 《空间科学学报》 CAS CSCD 北大核心 2004年第z1期102-115,共14页
This brief report summarized the latest advances of the heliospheric physics research in China during the period of 2002-2003, made independently by Chinese space physicists and through international collaboration. Th... This brief report summarized the latest advances of the heliospheric physics research in China during the period of 2002-2003, made independently by Chinese space physicists and through international collaboration. The report covers all aspects of the heliospheric physics, including theoretical studies, numerical simulation and data analysis. 展开更多
关键词 Solar WIND plasma CORONAL MASS ejection INTERPLANETARY shock Magnetic CLOUD
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PROGRESS IN HELIOSPHERIC PHYSICS
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作者 Feng Xueshang 《空间科学学报》 CAS CSCD 北大核心 2002年第z1期64-80,共17页
This is an overview of progresses in heliospheric physics made in China in the period of June, 2000 to May, 2002. The report is focused on theoretical studies,modelling and observational analysis of interplanetary phy... This is an overview of progresses in heliospheric physics made in China in the period of June, 2000 to May, 2002. The report is focused on theoretical studies,modelling and observational analysis of interplanetary physical phenomena, and consists of five sections: the acceleration and heating of the solar wind, corona structures, coronal mass ejections, magnetic reconnection phenomena, and in terplanetary transient phenomena. The main achievements made recently by Chinese scientists in related areas are simply listed in corresponding sections without any priority, only certain editorial consideration. 展开更多
关键词 Solar WIND acceleration CORONAL mass ejection Interplanetary Transient PHENOMENA
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WORLD NEWS IN BRIEF (March 16-31, 1991)
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《国际展望》 北大核心 1991年第7期32-32,共1页
Millions of people of the Soviet Union voted on March 17 in a referendum on the future of the Soviet Union which President Mikhail Gorhachev says could decide whether the vast state survives or breaks up. Six republic... Millions of people of the Soviet Union voted on March 17 in a referendum on the future of the Soviet Union which President Mikhail Gorhachev says could decide whether the vast state survives or breaks up. Six republics had refused to 展开更多
关键词 BREAKS decide NEWS ejection ELECTION NATIONWIDE WASHINGTON
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Research Progress of Solar Corona and Interplanetary Physics in China:2010—2012
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作者 ZHAO Xinhua XIANG Changqing 《空间科学学报》 CAS CSCD 北大核心 2012年第5期618-646,共29页
The scientific objective of solar corona and interplanetary research is the understanding of the various phenomena related to solar activities and their effects on the space environments of the Earth.Great progress ha... The scientific objective of solar corona and interplanetary research is the understanding of the various phenomena related to solar activities and their effects on the space environments of the Earth.Great progress has been made in the study of solar corona and interplanetary physics by the Chinese space physics community during the past years.This paper will give a brief report about the latest progress of the corona and interplanetary research in China during the years of 2010-2012.The paper can be divided into the following parts:solar corona and solar wind.CMEICME, magnetic reconnection,energetic particles,space plasma,space weather numerical modeling by 3D SIP-CESE MHD model,space weather prediction methods,and proposed missions.They constitute the abundant content of study for the complicated phenomena that originate from the solar corona,propagate in interplanetary space,and produce geomagnetic disturbances.All these progresses are acquired by the Chinese space physicists,either independently or through international collaborations. 展开更多
关键词 Solar wind Coronal Mass ejection(CME) Interplanetary transients Space weather
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