Frequencies of frequency standards are shifted by the local static gravity red shifts and also modulated by the tidal relativistic red shifts. We compute the tidal relativistic red shifts using a time-domain method an...Frequencies of frequency standards are shifted by the local static gravity red shifts and also modulated by the tidal relativistic red shifts. We compute the tidal relativistic red shifts using a time-domain method and present the numerical results for the National Institute of Metrology （NIM） in Beijing, Laboratoire National de Metrologie et Essais-Systeme de References Temps-Espaee （LNE-SYRTE） in Paris and Physikalisch-Teehnische Bundesanstalt （PTB） in Braunschweig. The differences of the tidal relativistic red shift approach as large as 1.1 × 10^-16 when frequency standards at NIM are compared with those at SYRTE and PTB. Moreover, the tidal relativistic red shifts of frequency standards in space stations are also computed.展开更多
The mode serials of the Earth’s free oscillation provide some important information on the Earth’s deep structure and superconducting gravimeters （SG） can investigate the phenomena of the Earth’s free oscillation...The mode serials of the Earth’s free oscillation provide some important information on the Earth’s deep structure and superconducting gravimeters （SG） can investigate the phenomena of the Earth’s free oscillations with high accuracy. The great Sumatra-Andaman earthquake fully excited the Earth’s free oscillations and these signals were perfectly recorded by five superconducting gravimeters in the globe. After the pre-treatment and spectral analysis on the SG observation data, we obtained the experimented mode serials of the Earth’s free oscillations consisting of 147 modes with GGP station data. These observed modes were themselves some new important data for the study of the Earth’s deep structure. On the basis of the discussions on some checked inner-core-sensitive modes, we distinguished three layers from the inner core, and the boundary of the upper layer was compatible with the formerly known transition zone in the inner core based on seismic body waves and supported that there were the hemispherical variation and very lower shear velocity zone in the lower inner core.展开更多
The stratosphere airship provides a unique and promising platform for earth observation. Researches on the project design and control scheme for earth observation platforms are still rarely documented. Nonlinear dynam...The stratosphere airship provides a unique and promising platform for earth observation. Researches on the project design and control scheme for earth observation platforms are still rarely documented. Nonlinear dynamics, model uncertainties, and external disturbances contribute to the difficulty in maneuvering the stratosphere airship. A key technical challenge for the earth observation platform is station keeping, or the ability to remain fixed over a geo-location. This paper investigates the conceptual design, modeling and station-keeping attitude control of the near-space earth observation platform. A conceptual design of the earth observation platform is presented. The dynamics model of the platform is derived from the Newton-Euler formulation, and the station-keeping control system of the platform is formulated. The station-keeping attitude control approach for the platform is proposed. The multi-input multi-output nonlinear control system is decoupled into three single-input single-output linear subsystems via feedback linearization, the attitude controller design is carried out on the new linear systems using terminal sliding mode control, and the global stability of the closed-loop system is proven by using the Lyapunov theorem. The performance of the designed control system is simulated by using the variable step Runge-Kutta integrator. Simulation results show that the control system tracks the commanded attitude with an error of zero, which verify the effectiveness and robustness of the designed control system in the presence of parametric uncertainties. The near-space earth observation platform has several advantages over satellites, such as high resolution, fast to deploy, and convenient to retrieve, and the proposed control scheme provides an effective approach for station-keeping attitude control of the earth observation platform.展开更多
针对无人机飞行监测和控制的要求,设计了一款飞行监测和控制的无人机遥控遥测地面站系统软件.无人机遥控遥测地面站系统软件包括系统调试、航迹规划、飞行监测、视频捕捉和数据回放等功能模块,融合Google Earth COM API二次开发技术基...针对无人机飞行监测和控制的要求,设计了一款飞行监测和控制的无人机遥控遥测地面站系统软件.无人机遥控遥测地面站系统软件包括系统调试、航迹规划、飞行监测、视频捕捉和数据回放等功能模块,融合Google Earth COM API二次开发技术基础上运用Visual C++6.0作为系统开发环境,采用模块化理念并嵌入串口通信技术、虚拟航空仪表技术、视频捕捉技术等进行软件开发.展开更多
An unidentified geophysical event is first reported in this paper. It was recorded with Lacoste & Romberg earth tide gravity meter (ET 21) at Chinese Antarctic Zhongshan Station.
Based on advanced computer technology,internet of things(IOT) technology,project management concept and professional technology and combined with the innovative theories,methods and techniques in earlier hydropower pr...Based on advanced computer technology,internet of things(IOT) technology,project management concept and professional technology and combined with the innovative theories,methods and techniques in earlier hydropower projects,the life- cycle risk management system of high earth- rock dam project for Nuozhadu project was developed. The system mainly includes digital dam,three-dimensional design,construction quality monitoring,safety assessment and warning,etc,to integrally manage and analyze the dam design,constructional quality and safety monitoring information. It realized the dynamic updates of the comprehensive information and the safety quality monitoring in the project life cycle,and provided the basic platform for the scientific management of the construction and operation safety of high earth- rock dam. Application in Nuozhadu earth- rock dam showed that construction safety monitoring and warning greatly helped accelerate the construction progress and improve project quality,and provided a new way for the quality safety control of high earth-rock dam.展开更多
基金Supported by the National Key R&D Program of China under Grant No 2016YFF0200200
文摘Frequencies of frequency standards are shifted by the local static gravity red shifts and also modulated by the tidal relativistic red shifts. We compute the tidal relativistic red shifts using a time-domain method and present the numerical results for the National Institute of Metrology （NIM） in Beijing, Laboratoire National de Metrologie et Essais-Systeme de References Temps-Espaee （LNE-SYRTE） in Paris and Physikalisch-Teehnische Bundesanstalt （PTB） in Braunschweig. The differences of the tidal relativistic red shift approach as large as 1.1 × 10^-16 when frequency standards at NIM are compared with those at SYRTE and PTB. Moreover, the tidal relativistic red shifts of frequency standards in space stations are also computed.
基金supported jointly by the National Natural Science Foundation of China (Nos. 40974046,90814009 and 40730316)the Natural Science Foundation of Hubei Province (No. 2008CDB389)the Knowledge Innovation Project of Chinese Academy of Sciences (No. KZCX2-YW-133)
文摘The mode serials of the Earth’s free oscillation provide some important information on the Earth’s deep structure and superconducting gravimeters （SG） can investigate the phenomena of the Earth’s free oscillations with high accuracy. The great Sumatra-Andaman earthquake fully excited the Earth’s free oscillations and these signals were perfectly recorded by five superconducting gravimeters in the globe. After the pre-treatment and spectral analysis on the SG observation data, we obtained the experimented mode serials of the Earth’s free oscillations consisting of 147 modes with GGP station data. These observed modes were themselves some new important data for the study of the Earth’s deep structure. On the basis of the discussions on some checked inner-core-sensitive modes, we distinguished three layers from the inner core, and the boundary of the upper layer was compatible with the formerly known transition zone in the inner core based on seismic body waves and supported that there were the hemispherical variation and very lower shear velocity zone in the lower inner core.
基金supported by Hunan Provincial Innovation Foundation for Postgraduate(Grant No. CX2011B005)National University of Defense Technology Innovation Foundation for Postgraduate, China(GranNo. B110105)
文摘The stratosphere airship provides a unique and promising platform for earth observation. Researches on the project design and control scheme for earth observation platforms are still rarely documented. Nonlinear dynamics, model uncertainties, and external disturbances contribute to the difficulty in maneuvering the stratosphere airship. A key technical challenge for the earth observation platform is station keeping, or the ability to remain fixed over a geo-location. This paper investigates the conceptual design, modeling and station-keeping attitude control of the near-space earth observation platform. A conceptual design of the earth observation platform is presented. The dynamics model of the platform is derived from the Newton-Euler formulation, and the station-keeping control system of the platform is formulated. The station-keeping attitude control approach for the platform is proposed. The multi-input multi-output nonlinear control system is decoupled into three single-input single-output linear subsystems via feedback linearization, the attitude controller design is carried out on the new linear systems using terminal sliding mode control, and the global stability of the closed-loop system is proven by using the Lyapunov theorem. The performance of the designed control system is simulated by using the variable step Runge-Kutta integrator. Simulation results show that the control system tracks the commanded attitude with an error of zero, which verify the effectiveness and robustness of the designed control system in the presence of parametric uncertainties. The near-space earth observation platform has several advantages over satellites, such as high resolution, fast to deploy, and convenient to retrieve, and the proposed control scheme provides an effective approach for station-keeping attitude control of the earth observation platform.
文摘针对无人机飞行监测和控制的要求,设计了一款飞行监测和控制的无人机遥控遥测地面站系统软件.无人机遥控遥测地面站系统软件包括系统调试、航迹规划、飞行监测、视频捕捉和数据回放等功能模块,融合Google Earth COM API二次开发技术基础上运用Visual C++6.0作为系统开发环境,采用模块化理念并嵌入串口通信技术、虚拟航空仪表技术、视频捕捉技术等进行软件开发.
文摘An unidentified geophysical event is first reported in this paper. It was recorded with Lacoste & Romberg earth tide gravity meter (ET 21) at Chinese Antarctic Zhongshan Station.
文摘Based on advanced computer technology,internet of things(IOT) technology,project management concept and professional technology and combined with the innovative theories,methods and techniques in earlier hydropower projects,the life- cycle risk management system of high earth- rock dam project for Nuozhadu project was developed. The system mainly includes digital dam,three-dimensional design,construction quality monitoring,safety assessment and warning,etc,to integrally manage and analyze the dam design,constructional quality and safety monitoring information. It realized the dynamic updates of the comprehensive information and the safety quality monitoring in the project life cycle,and provided the basic platform for the scientific management of the construction and operation safety of high earth- rock dam. Application in Nuozhadu earth- rock dam showed that construction safety monitoring and warning greatly helped accelerate the construction progress and improve project quality,and provided a new way for the quality safety control of high earth-rock dam.
