The security challenges from room and pillar gobs include land subsidence, spontaneous combustion of coal pillars and mine flood caused by gob water. To explore the instability mechanism of room and pillar gob, we est...The security challenges from room and pillar gobs include land subsidence, spontaneous combustion of coal pillars and mine flood caused by gob water. To explore the instability mechanism of room and pillar gob, we established a mechanical model of elastic plate on elastic foundation in which pillars and hard roofs were considered as continuous Winkler foundations and elastic plates, respectively. The synergetic instability of pillar and roof system was analyzed based on plate bending theory and catastrophe theory. In addition, mechanical conditions and math criterion of roof failure and overall instability of coal pillar and roof system were given. Through analyzing both advantages and disadvantages of some technologies such as induced caving, filling, gob sealing and isolation, we presented a new filling method named box-filling, in view of box foundation theory, to control the disasters of ground collapse, water inrush and mine fire. In a gob's treatment project in Ordos, safety assessment and filling design of a room and pillar gob have been done by the mechanical model. The results show that the gob will collapse when the pillars' average yield band is wider than 0.93 m, and box-filling can control land collapse, mine flood and mine fire economically and efficiently. So it is worth to study further and popularize.展开更多
The Essential Climate Variables(ECVs),such as the atmospheric thermodynamic state variables and greenhouse gases,play an important role in the atmosphere physical processes and global climate change.Given the need of ...The Essential Climate Variables(ECVs),such as the atmospheric thermodynamic state variables and greenhouse gases,play an important role in the atmosphere physical processes and global climate change.Given the need of improvements in existing ground-based and satellite observations to successfully deliver atmosphere and climate benchmark data and reduce data ambiguity,the Climate and Atmospheric Composition Exploring Satellites mission(CACES)was proposed and selected as a candidate mission of the Strategic Priority Research Program of Chinese Academy Science(SPRPCAS).This paper presents an overview of the key scientific questions and responses of EC Vs in relation to global change;the principles,algorithms,and payloads of microwave occultation using centimeter and millimeter wave signals between low Earth orbit satellites(LEO-LEO microwave occultation,LMO)as well as of the LEO-LEO infrared-laser occultation(LIO);the CACES mission with its scientific objectives,mission concept,spacecraft and instrumentation.展开更多
The first Global Navigation Satellite System Occultation Sounder(GNOS) which is compatible of both Bei Dou System(BDS)and Global Positioning System(GPS) was successfully launched into orbit onboard the Feng Yun 3 C sa...The first Global Navigation Satellite System Occultation Sounder(GNOS) which is compatible of both Bei Dou System(BDS)and Global Positioning System(GPS) was successfully launched into orbit onboard the Feng Yun 3 C satellite(FY-3 C) on September 23, 2013, and it has already gathered a large amount of ionosphere radio occultation(RO) data so far. However, the detailed analysis and validation of GPS ionosphere RO data have not been done up to now. Therefore, this paper discusses the configuration of the FY-3 C GNOS, the methods and results of GPS ionosphere occultation processment, the quality analysis of the GPS ionosphere RO products, and the precision consistency between the GNOS GPS ionosphere RO product and ionosonde data. The peak electron density(Nm F2) correlation coefficient is 0.97, the corresponding standard deviation is 16.08%. The peak value altitude(hm F2) correlation coefficient is 0.89, and the corresponding standard deviation is 23.79 km. The in-orbit operation of GNOS provides a basis data set for the monitoring, forecasting and research of ionosphere's space weather.展开更多
基金provided by the National Natural Science Foundation of China (No. 41071273)
文摘The security challenges from room and pillar gobs include land subsidence, spontaneous combustion of coal pillars and mine flood caused by gob water. To explore the instability mechanism of room and pillar gob, we established a mechanical model of elastic plate on elastic foundation in which pillars and hard roofs were considered as continuous Winkler foundations and elastic plates, respectively. The synergetic instability of pillar and roof system was analyzed based on plate bending theory and catastrophe theory. In addition, mechanical conditions and math criterion of roof failure and overall instability of coal pillar and roof system were given. Through analyzing both advantages and disadvantages of some technologies such as induced caving, filling, gob sealing and isolation, we presented a new filling method named box-filling, in view of box foundation theory, to control the disasters of ground collapse, water inrush and mine fire. In a gob's treatment project in Ordos, safety assessment and filling design of a room and pillar gob have been done by the mechanical model. The results show that the gob will collapse when the pillars' average yield band is wider than 0.93 m, and box-filling can control land collapse, mine flood and mine fire economically and efficiently. So it is worth to study further and popularize.
基金Supported by the National Natural Science Foundation of China(41775034,41606206)the Strategic Priority Research Program of Chinese Academy of Sciences(XDA15012300)。
文摘The Essential Climate Variables(ECVs),such as the atmospheric thermodynamic state variables and greenhouse gases,play an important role in the atmosphere physical processes and global climate change.Given the need of improvements in existing ground-based and satellite observations to successfully deliver atmosphere and climate benchmark data and reduce data ambiguity,the Climate and Atmospheric Composition Exploring Satellites mission(CACES)was proposed and selected as a candidate mission of the Strategic Priority Research Program of Chinese Academy Science(SPRPCAS).This paper presents an overview of the key scientific questions and responses of EC Vs in relation to global change;the principles,algorithms,and payloads of microwave occultation using centimeter and millimeter wave signals between low Earth orbit satellites(LEO-LEO microwave occultation,LMO)as well as of the LEO-LEO infrared-laser occultation(LIO);the CACES mission with its scientific objectives,mission concept,spacecraft and instrumentation.
基金supported by the Special Fund for Public Welfare Industry(Grant Nos.GYHY201006048 and GYHY201306063)the National Natural Science Foundation of China(Grant Nos.41505030,41405039,41405040and 41606206)the Scientific Research Project of the Chinese Academy of Sciences(Grant No.YZ201129)
文摘The first Global Navigation Satellite System Occultation Sounder(GNOS) which is compatible of both Bei Dou System(BDS)and Global Positioning System(GPS) was successfully launched into orbit onboard the Feng Yun 3 C satellite(FY-3 C) on September 23, 2013, and it has already gathered a large amount of ionosphere radio occultation(RO) data so far. However, the detailed analysis and validation of GPS ionosphere RO data have not been done up to now. Therefore, this paper discusses the configuration of the FY-3 C GNOS, the methods and results of GPS ionosphere occultation processment, the quality analysis of the GPS ionosphere RO products, and the precision consistency between the GNOS GPS ionosphere RO product and ionosonde data. The peak electron density(Nm F2) correlation coefficient is 0.97, the corresponding standard deviation is 16.08%. The peak value altitude(hm F2) correlation coefficient is 0.89, and the corresponding standard deviation is 23.79 km. The in-orbit operation of GNOS provides a basis data set for the monitoring, forecasting and research of ionosphere's space weather.
