Since 2011,the Chinese Academy of Sciences(CAS)has implemented the Strategic Priority Program on Space Science(SPP).A series of scientific satellites have been developed and launched,such as Dark Matter Particle Explo...Since 2011,the Chinese Academy of Sciences(CAS)has implemented the Strategic Priority Program on Space Science(SPP).A series of scientific satellites have been developed and launched,such as Dark Matter Particle Explorer(DAMPE),Quantum Experiments at Space Scale(QUESS),Advanced Space-based Solar Observatory(ASO-S),Einstein Probe(EP),and significant scientific outcomes have been achieved.In order to plan the future space science missions in China,CAS has organized the Chinese space science community to conduct medium and long-term development strategy studies,and summarized the major scientific frontiers of space science as“One Black,Two Dark,Three Origins and Five Characterizations”.Five main scientific themes have been identified for China’s future breakthroughs,including the Extreme Universe,Space-Time Ripples,the Panoramic View of the Sun and Earth,the Habitable Planets,and Biological&Physical Science in Space.Space science satellite missions to be implemented before 2030 are proposed accordingly.展开更多
Considering current space debris situation in outer space environment,different methods for debris removal missions are proposed.In addition,advanced technologies are needed to be demonstrated for future human space e...Considering current space debris situation in outer space environment,different methods for debris removal missions are proposed.In addition,advanced technologies are needed to be demonstrated for future human space exploration programs.The main issue regarding to these missions is high mission cost for both debris removal missions and space environmental tests to achieve high maturity level for new space-usable technologies.Since,these missions are unavoidable for future of human space activities,a solution which can tackle these challenges is necessary.This paper will address to an idea which has the possibility to give a solution for facilitating technology readiness level(TRL)maturity tests by debris removal mission platform consideration.展开更多
Improvement of integrated battlefield situational awareness in complex environments involving dynamic factors such as restricted communications and electromagnetic interference(EMI)has become a contentious research pr...Improvement of integrated battlefield situational awareness in complex environments involving dynamic factors such as restricted communications and electromagnetic interference(EMI)has become a contentious research problem.In certain mission environments,due to the impact of many interference sources on real-time communication or mission requirements such as the need to implement communication regulations,the mission stages are represented as a dynamic combination of several communication-available and communication-unavailable stages.Furthermore,the data interaction between unmanned aerial vehicles(UAVs)can only be performed in specific communication-available stages.Traditional cooperative search algorithms cannot handle such situations well.To solve this problem,this study constructed a distributed model predictive control(DMPC)architecture for a collaborative control of UAVs and used the Voronoi diagram generation method to re-plan the search areas of all UAVs in real time to avoid repetition of search areas and UAV collisions while improving the search efficiency and safety factor.An attention mechanism ant-colony optimization(AACO)algorithm is proposed for UAV search-control decision planning.The search strategy is adaptively updated by introducing an attention mechanism for regular instruction information,a priori information,and emergent information of the mission to satisfy different search expectations to the maximum extent.Simulation results show that the proposed algorithm achieves better search performance than traditional algorithms in restricted communication constraint scenarios.展开更多
China has successfully launched six lunar probes so far.From Chang'E-1 to Chang'E-4,they completed the circling,landing and roving exploration,of which Chang'E-4 was the first landing on the far side of th...China has successfully launched six lunar probes so far.From Chang'E-1 to Chang'E-4,they completed the circling,landing and roving exploration,of which Chang'E-4 was the first landing on the far side of the Moon in human history.Chang'E-5 was launched in December 2020,bringing back 1731 g of lunar soil samples.Through the detailed analysis of the samples,the scientists understand the history of late lunar volcanism,specifically extending lunar volcanism by about 800 million to 1 billion years,and proposed possible mechanisms.In addition,there are many new understandings of space weathering such as meteorite impacts and solar wind radiation on the Moon.China's first Mars exploration mission Tianwen-1 was successfully launched in July 2021.Through the study of scientific data,a number of important scientific achievements have been made in the topography,water environment and shallow surface structure of Mars.This paper introduces the main scientific achievements of Chang'E-4,Chang'E-5 and Tianwen-1 in the past two years,excluding technical and engineering contents.Due to the large number of articles involved,this paper only introduces part of the results.展开更多
Choosing the best path during unmanned air vehicle （UAV） flying is the target of the UAV mission planning problem. Because of its nearly constant flight height, the UAV mission planning problem can be treated as a 2...Choosing the best path during unmanned air vehicle （UAV） flying is the target of the UAV mission planning problem. Because of its nearly constant flight height, the UAV mission planning problem can be treated as a 2-D （horizontal） path arrangement problem. By modeling the antiaircraft threat, the UAV mission planning can be mapped to the traveling seaman problem （TSP）. A new algorithm is presented to solve the TSP. The algorithm combines the traditional ant colony system （ACS） with particle swarm optimization （PSO）, thus being called the AC-PSO algorithm. It uses one by one tour building strategy like ACS to determine that the target point can be chosen like PSO. Experiments show that AC-PSO synthesizes both ACS and PSO and obtains excellent solution of the UAV mission planning with a higher accuracy.展开更多
The Strategic Priority Program(SPP)on Space Science,which is under the leadership of the Chinese Academy of Sciences(CAS),has established China’s space science satellite series from scratch.A number of major scientif...The Strategic Priority Program(SPP)on Space Science,which is under the leadership of the Chinese Academy of Sciences(CAS),has established China’s space science satellite series from scratch.A number of major scientific achievements have been made by the first phase of the Program(SPPⅠ),while SPPⅡhas been currently being implemented.The future development of space science needs urgent top-level planning and advanced layout to clarify the overall goal and investment portfolio from 2025 to 2030.We will briefly introduce the initiative and possible space science missions of SPPⅢ,including the preparatory work which already started in July 2021.Following the effective administrative tradition since SPPⅠ,National Space Science Center(NSSC,CAS)is responsible for the whole procedure,including soliciting,assessment,and implementation of SPPⅢ.Brief information on the 13 candidate missions will be described,including missions in the fields of astronomy&astrophysics,exoplanets,heliophysics and planetary&Earth science,respectively.展开更多
In May 2018,the second phase of the Strategic Priority Program on Space Science(SPP II)was officially approved by the Chinese Academy of Sciences,in view of the significant scientific achievements of the first phase o...In May 2018,the second phase of the Strategic Priority Program on Space Science(SPP II)was officially approved by the Chinese Academy of Sciences,in view of the significant scientific achievements of the first phase of the Strategic Priority Program on Space Science(SPP I)which includes 4 space science missions:the Dark Matter Particle Explorer(DAMPE),ShiJian-10(SJ-10),Quantum Experiments at Space Scale(QUESS)and Hard X-ray Modulation Telescope(HXMT).Aiming to address fundamental scientific questions,SPP II focuses on two major themes:How the universe and life originate and evolve and What is the relationship between the solar system and human beings.In areas that Chinese scientists have advantages,new space science missions including Graviational wave high-energy Electromagnetic Counterpart All-sky Monitor(GECAM),the Advanced space-based Solar Observatory(ASO-S),the Einstein Probe(EP),and Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)have been approved in the framework of SPP II.This paper presents the research highlights of the SPP I,introduces the recent progress of SPP II,and puts forward the prospects for future development.展开更多
Backgrounds： There are many satellite systems acquiring environmental data on the world. Acquired global remote sensing datasets require ground reference data in order to calibrate them and assess their quality. Rega...Backgrounds： There are many satellite systems acquiring environmental data on the world. Acquired global remote sensing datasets require ground reference data in order to calibrate them and assess their quality. Regarding calibration and validation of these datasets with broad geographical extents, it is essential to register zones which might be considered as Homogeneous Patches （HPs）. Such patches enable an optimal calibration of satellite data/sensors, and what is more important is an analysis of components which significantly influence electro-magnetic signals registered by satellite sensors. Methods： We proposed two structurally different methods to identify HPs： predefined thresholding-based one （static one）, and statistical thresholding-based technique （dynamic one）. In the first method, 3 different thresholds were used： 5%, 10%, and 20%. Next, it was aimed to assess how delineated HPs were spatially matched to satellite data with coarse spatial resolution. Selected cell sizes were 25, 50, 100, 250, and 500 m. The number of particular grid cells which almost entirely fell into registered HPs was counted （leaving 2% cell area tolerance level）. This procedure was executed separately for each variant and selected structural variables, as well as for their intersection parts. Results： The results of this investigation revealed that ALS data might have the potential in the identification of HPs of forest stands. We showed that different ALS based variables and thresholds of HPs definition influenced areas which can be treated as similar and homogeneous. We proved that integration of more than one structural variable limits size of the HPs, in contrast, visual interpretation revealed that inside such patches vegetation structure is more constant. Conclusions： We concluded that ALS data can be used as a potential source of data to ＂enlarge＂ small ground sample plots and to be used for evaluation and calibration of remotely sensed datasets provided by global systems with coarse spatial resolutions.展开更多
The microstrip dual-mode filter （DMF） with conventional coupling structure has some limitations in- eluding the port coupling strength limited by fabrication tolerance and the existence of serious second order spuri...The microstrip dual-mode filter （DMF） with conventional coupling structure has some limitations in- eluding the port coupling strength limited by fabrication tolerance and the existence of serious second order spuri- ous band. Therefore, a novel DMF with a offset-feed bended coupling structure and a stepped-impedance dual- mode resonator is proposed for coupling enhancement and spurious response suppression. Based on the analysis of the change of spur frequencies and the current distribution of spur resonant modes, all spurs near passband of the cascaded DMF can be fully suppressed by optimizing the structure parameters of parasite resonators, which bene- fits from the inherent well-controlled transmission zeros. Experimental results show that the proposed DMF ex- hibits lower insertion loss ,much sharper rate of cutoff and wider spur-free stop band compared with conventional DMF. This design is applicable for spur suppression in wideband communication.展开更多
Autonomous Underwater Vehicles （AUVs） are capable of conducting various underwater missions and marine tasks over long periods of time. In this study, a novel conflict-free motion-planning framework is introduced. T...Autonomous Underwater Vehicles （AUVs） are capable of conducting various underwater missions and marine tasks over long periods of time. In this study, a novel conflict-free motion-planning framework is introduced. This framework enhances AUV mission performance by completing the maximum number of highest priority tasks in a limited time through a large-scale waypoint cluttered operating field and ensuring safe deployment during the mission. The proposed combinatorial route-path-planner model takes advantage of the Biogeography- Based Optimization （BBO） algorithm to satisfy the objectives of both higher- and lower-level motion planners and guarantee the maximization of mission productivity for a single vehicle operation. The performance of the model is investigated under different scenarios, including cost constraints in time-varying operating fields. To demonstrate the reliability of the proposed model, the performance of each motion planner is separately assessed and statistical analysis is conducted to evaluate the total performance of the entire model. The simulation results indicate the stability of the proposed model and the feasibility of its application to real-time experiments.展开更多
The KuaFu mission-Space Storms,Aurora and Space Weather Explorer-is an"L1+Polar"triple satellite project composed of three spacecraft:KuaFu-A will be located at L1 and have instruments to observe solar EUV a...The KuaFu mission-Space Storms,Aurora and Space Weather Explorer-is an"L1+Polar"triple satellite project composed of three spacecraft:KuaFu-A will be located at L1 and have instruments to observe solar EUV and FUV emissions,and white-light Coronal Mass Ejections(CMEs),and to measure radio waves,the local plasma and magnetic field,and high-energy particles.KuaFuB1 and KuaFu-B2 will bein polar orbits chosen to facilitate continuous 24 hours a day observation of the north polar Aurora Oval.The KuaFu mission is designed to observe the complete chain of disturbances from the solar atmosphere to geospace,including solar flares,CMEs,interplanetary clouds,shock waves,and their geo-effects,such as magnetospheric sub-storms and magnetic storms,and auroral activities.The mission may start at the next solar maximum(launch in about 2012),and with an initial mission lifetime of two to three years.KuaFu data will be used for the scientific study of space weather phenomena,and will be used for space weather monitoring and forecast purposes.The overall mission design,instrument complement,and incorporation of recent technologies will target new fundamental science,advance our understanding of the physical processes underlying space weather,and raise the standard of end-to-end monitoring of the Sun-Earth system.展开更多
SMESE (SMall Explorer For the study of Solar Eruptions) is a Franco-Chinese Microsatellite mission. The scientific objectives of SMESE are the study of coronal mass ejections and flares. Its payload consists of three ...SMESE (SMall Explorer For the study of Solar Eruptions) is a Franco-Chinese Microsatellite mission. The scientific objectives of SMESE are the study of coronal mass ejections and flares. Its payload consists of three instrument packages: LYOT, DESIR and HEBS. LYOT is com-posed of a Ly-α (121.6 nm) coronagraph, a Ly-α disk imager and a far UV disk imager. DESIR is an infrared telescope working at 35μm and 150μm. HEBS is a high energy burst spectrometer working in X-rays and γ-rays covering the 10keV to 600 MeV range. SMESE will be launched around 2011, providing a unique opportunity of detecting and understanding eruptions at the maximum activity phase of the solar cycle in a wide range of energies.展开更多
The majority of allied casualties from recent conflicts were caused by blast wave and fragments perforation damage from Improvised Explosive Devices. Survivability to this type of threat is a critical factor to consid...The majority of allied casualties from recent conflicts were caused by blast wave and fragments perforation damage from Improvised Explosive Devices. Survivability to this type of threat is a critical factor to consider for land platform design. This paper proposes an original approach to platform survivability assessment using a combination of Agent-Based(AB) simulation and Fault Tree Analysis(FTA) to predict the consequences of IED fragment impacts on the platform operational status. As a demonstration, this approach is applied to the comparison of different platform architectures to gain insight into the optimisation of the platform component topology.展开更多
The CSES(China Seismo-Electromagnetic Satellite)is the electromagnetism satellite of China’s Zhangheng mission which is planned to launch a series of microsatellites within next 10 years in order to monitor the elect...The CSES(China Seismo-Electromagnetic Satellite)is the electromagnetism satellite of China’s Zhangheng mission which is planned to launch a series of microsatellites within next 10 years in order to monitor the electromagnetic environment,gravitational field.The CSES 01 probe(also called ZH-1)was launched successfully on 2 February 2018,from the Jiuquan Satellite Launch Centre(China)and is expected to operate for 5 years in orbit.The second probe CSES 02 is going to be launched in 2022.The scientific objectives of CSES are to detect the electromagnetic field and waves,plasma and particles,for studying the seismic-associated disturbances.To meet the requirements of scientific objective,the satellite is designed to be in a sun-synchronous orbit with a high inclination of 97.4°at an altitude around 507 km.CSES carries nine scientific payloads including Search-coil magnetometer,Electric Field Detector,High precision Magnetometer,GNSS occultation Receiver,Plasma Analyzer,Langmuir Probe,two Energetic Particle Detectors(including an Italian one),and Tri-Band Transmitter.Up to now,CSES has been operating in orbit for 2 years with stable and reliable performance.By using all kinds of data acquired by CSES,we have undertaken a series of scientific researches in the field of global geomagnetic field re-building,the ionospheric variation environment,waves,and particle precipitations under disturbed space weather and earthquake activities,the Lithosphere-Atmosphere-Ionosphere coupling mechanism research and so on.展开更多
In space-based gravitational wave detection, the estimation of far-field wavefront error of the distorted beam is the precondition for the noise reduction. Zernike polynomials are used to describe the wavefront error ...In space-based gravitational wave detection, the estimation of far-field wavefront error of the distorted beam is the precondition for the noise reduction. Zernike polynomials are used to describe the wavefront error of the transmitted distorted beam. The propagation of a laser beam between two telescope apertures is calculated numerically. Far-field wavefront error is estimated with the absolute height of the peak-to-valley phase deviation between the distorted Gaussian beam and a reference distortion-free Gaussian beam. The results show that the pointing jitter is strongly related to the wavefront error. Furthermore, when the jitter decreases 10 times from 100 nrad to 10 nrad, the wavefront error reduces for more than an order of magnitude. In the analysis of multi-parameter minimization, the minimum of wavefront error tends to Z[5,3] Zernike in some parameter ranges. Some Zernikes have a strong correlation with the wavefront error of the received beam. When the aperture diameter increases at Z[5,3] Zernike, the wavefront error is not monotonic and has oscillation.Nevertheless, the wavefront error almost remains constant with the arm length increasing from 10-1Mkm to 10~3Mkm.When the arm length decreases for three orders of magnitude from 10-1Mkm to 10-4Mkm, the wavefront error has only an order of magnitude increasing. In the range of 10-4Mkm to 10~3Mkm, the lowest limit of the wavefront error is from 0.5 fm to 0.015 fm at Z[5,3] Zernike and 10 nrad jitter.展开更多
In the wake of the rapid economy and society development, phenomena such as industri-alisation, urbanisation, marketisation and the ageing of the population have shown an accelerating trend. As a result, mental health...In the wake of the rapid economy and society development, phenomena such as industri-alisation, urbanisation, marketisation and the ageing of the population have shown an accelerating trend. As a result, mental health issues due to these phenomena are increasingly serious, making mental health both concerning public health and societal issues that have a great impact on economic and social development.^1 In 2014, there were 16 million persons with severe mental disor-ders in China.展开更多
China’s first Mars exploration mission is scheduled to be launched in 2020.It aims not only to conduct global and comprehensive exploration of Mars by use of an orbiter but also to carry out in situ observation of ke...China’s first Mars exploration mission is scheduled to be launched in 2020.It aims not only to conduct global and comprehensive exploration of Mars by use of an orbiter but also to carry out in situ observation of key sites on Mars with a rover.This mission focuses on the following studies:topography,geomorphology,geological structure,soil characteristics,water-ice distribution,material composition,atmosphere and ionosphere,surface climate,environmental characteristics,Mars internal structure,and Martian magnetic field.It is comprised of an orbiter,a lander,and a rover equipped with 13 scientific payloads.This article will give an introduction to the mission including mission plan,scientific objectives,scientific payloads,and its recent development progress.展开更多
Considering the bad condition and shortage of medical resource in Sudan peacekeeping mission area, the author contrives the procedure of CASEVAC/MEDEVAC, including definition, request, authorization, operation and mis...Considering the bad condition and shortage of medical resource in Sudan peacekeeping mission area, the author contrives the procedure of CASEVAC/MEDEVAC, including definition, request, authorization, operation and miscellaneous, and stipulates the responsibility of parties concerned. The aim is to ensure systematic, organized and timely evacuation of patients to the most suitable medical facility for each individual case,thereby to minimize the loss of lives and limbs.展开更多
Space radiation has been identified as the main health hazard to crews involved in manned Mars missions.Active shielding is more effective than passive shielding to the very energetic particles from cosmic rays.Partic...Space radiation has been identified as the main health hazard to crews involved in manned Mars missions.Active shielding is more effective than passive shielding to the very energetic particles from cosmic rays.Particle motion in a magnetic field is studied based on the single-particle theory and Monte Carlo method.By comparing the shielding efficiency of different magnetic field configurations,a novel active magnetic shielding configuration with lower mass cost and power consumption is proposed for manned Mars missions.The new magnetic configuration can shield 92.8%of protons and 84.4%of alpha particles with E<4 GeV·n^(-1),when considering the passive shielding contribution of 10.0 g·cm^(-2) Al Shielding,the required magnetic stiffness can be reduced from 27 Tm to 16 Tm.The detailed analysis of mass cost and power consumption shows that active shielding will be a promising means to protect crews from space radiation exposure in manned Mars missions.展开更多
基金Supported by Consultation and Evaluation Program on Academic Divisions of the Chinese Academy of Sciences(2022-DX02-B-007)。
文摘Since 2011,the Chinese Academy of Sciences(CAS)has implemented the Strategic Priority Program on Space Science(SPP).A series of scientific satellites have been developed and launched,such as Dark Matter Particle Explorer(DAMPE),Quantum Experiments at Space Scale(QUESS),Advanced Space-based Solar Observatory(ASO-S),Einstein Probe(EP),and significant scientific outcomes have been achieved.In order to plan the future space science missions in China,CAS has organized the Chinese space science community to conduct medium and long-term development strategy studies,and summarized the major scientific frontiers of space science as“One Black,Two Dark,Three Origins and Five Characterizations”.Five main scientific themes have been identified for China’s future breakthroughs,including the Extreme Universe,Space-Time Ripples,the Panoramic View of the Sun and Earth,the Habitable Planets,and Biological&Physical Science in Space.Space science satellite missions to be implemented before 2030 are proposed accordingly.
基金Supported by the National Natural Science Foundation of China(11572037)
文摘Considering current space debris situation in outer space environment,different methods for debris removal missions are proposed.In addition,advanced technologies are needed to be demonstrated for future human space exploration programs.The main issue regarding to these missions is high mission cost for both debris removal missions and space environmental tests to achieve high maturity level for new space-usable technologies.Since,these missions are unavoidable for future of human space activities,a solution which can tackle these challenges is necessary.This paper will address to an idea which has the possibility to give a solution for facilitating technology readiness level(TRL)maturity tests by debris removal mission platform consideration.
基金the support of the National Natural Science Foundation of China(Grant No.62076204)the Seed Foundation of Innovation and Creation for Graduate Students in Northwestern Polytechnical University(Grant No.CX2020019)in part by the China Postdoctoral Science Foundation(Grants No.2021M700337)。
文摘Improvement of integrated battlefield situational awareness in complex environments involving dynamic factors such as restricted communications and electromagnetic interference(EMI)has become a contentious research problem.In certain mission environments,due to the impact of many interference sources on real-time communication or mission requirements such as the need to implement communication regulations,the mission stages are represented as a dynamic combination of several communication-available and communication-unavailable stages.Furthermore,the data interaction between unmanned aerial vehicles(UAVs)can only be performed in specific communication-available stages.Traditional cooperative search algorithms cannot handle such situations well.To solve this problem,this study constructed a distributed model predictive control(DMPC)architecture for a collaborative control of UAVs and used the Voronoi diagram generation method to re-plan the search areas of all UAVs in real time to avoid repetition of search areas and UAV collisions while improving the search efficiency and safety factor.An attention mechanism ant-colony optimization(AACO)algorithm is proposed for UAV search-control decision planning.The search strategy is adaptively updated by introducing an attention mechanism for regular instruction information,a priori information,and emergent information of the mission to satisfy different search expectations to the maximum extent.Simulation results show that the proposed algorithm achieves better search performance than traditional algorithms in restricted communication constraint scenarios.
文摘China has successfully launched six lunar probes so far.From Chang'E-1 to Chang'E-4,they completed the circling,landing and roving exploration,of which Chang'E-4 was the first landing on the far side of the Moon in human history.Chang'E-5 was launched in December 2020,bringing back 1731 g of lunar soil samples.Through the detailed analysis of the samples,the scientists understand the history of late lunar volcanism,specifically extending lunar volcanism by about 800 million to 1 billion years,and proposed possible mechanisms.In addition,there are many new understandings of space weathering such as meteorite impacts and solar wind radiation on the Moon.China's first Mars exploration mission Tianwen-1 was successfully launched in July 2021.Through the study of scientific data,a number of important scientific achievements have been made in the topography,water environment and shallow surface structure of Mars.This paper introduces the main scientific achievements of Chang'E-4,Chang'E-5 and Tianwen-1 in the past two years,excluding technical and engineering contents.Due to the large number of articles involved,this paper only introduces part of the results.
文摘Choosing the best path during unmanned air vehicle （UAV） flying is the target of the UAV mission planning problem. Because of its nearly constant flight height, the UAV mission planning problem can be treated as a 2-D （horizontal） path arrangement problem. By modeling the antiaircraft threat, the UAV mission planning can be mapped to the traveling seaman problem （TSP）. A new algorithm is presented to solve the TSP. The algorithm combines the traditional ant colony system （ACS） with particle swarm optimization （PSO）, thus being called the AC-PSO algorithm. It uses one by one tour building strategy like ACS to determine that the target point can be chosen like PSO. Experiments show that AC-PSO synthesizes both ACS and PSO and obtains excellent solution of the UAV mission planning with a higher accuracy.
基金Supported by Strategic Priority Research Program of the Chinese Academy of Sciences(XDA15060102)。
文摘The Strategic Priority Program(SPP)on Space Science,which is under the leadership of the Chinese Academy of Sciences(CAS),has established China’s space science satellite series from scratch.A number of major scientific achievements have been made by the first phase of the Program(SPPⅠ),while SPPⅡhas been currently being implemented.The future development of space science needs urgent top-level planning and advanced layout to clarify the overall goal and investment portfolio from 2025 to 2030.We will briefly introduce the initiative and possible space science missions of SPPⅢ,including the preparatory work which already started in July 2021.Following the effective administrative tradition since SPPⅠ,National Space Science Center(NSSC,CAS)is responsible for the whole procedure,including soliciting,assessment,and implementation of SPPⅢ.Brief information on the 13 candidate missions will be described,including missions in the fields of astronomy&astrophysics,exoplanets,heliophysics and planetary&Earth science,respectively.
基金Supported by the Strategic Priority Program on Space Science of the Chinese Academy of Sciences(XDA15000000)。
文摘In May 2018,the second phase of the Strategic Priority Program on Space Science(SPP II)was officially approved by the Chinese Academy of Sciences,in view of the significant scientific achievements of the first phase of the Strategic Priority Program on Space Science(SPP I)which includes 4 space science missions:the Dark Matter Particle Explorer(DAMPE),ShiJian-10(SJ-10),Quantum Experiments at Space Scale(QUESS)and Hard X-ray Modulation Telescope(HXMT).Aiming to address fundamental scientific questions,SPP II focuses on two major themes:How the universe and life originate and evolve and What is the relationship between the solar system and human beings.In areas that Chinese scientists have advantages,new space science missions including Graviational wave high-energy Electromagnetic Counterpart All-sky Monitor(GECAM),the Advanced space-based Solar Observatory(ASO-S),the Einstein Probe(EP),and Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)have been approved in the framework of SPP II.This paper presents the research highlights of the SPP I,introduces the recent progress of SPP II,and puts forward the prospects for future development.
基金supported by the project REMBIOFOR(Remote sensing based assessment of woody biomass and carbon storage in forests)supported by The National Centre for Research and Development under BIOSTRATEG program,agreement no.BIOSTRATEG1/267755/4/NCBR/2015invented under the DUE GLOBBIOMASS project(contract 4,000,113,100/14/l-NB)
文摘Backgrounds： There are many satellite systems acquiring environmental data on the world. Acquired global remote sensing datasets require ground reference data in order to calibrate them and assess their quality. Regarding calibration and validation of these datasets with broad geographical extents, it is essential to register zones which might be considered as Homogeneous Patches （HPs）. Such patches enable an optimal calibration of satellite data/sensors, and what is more important is an analysis of components which significantly influence electro-magnetic signals registered by satellite sensors. Methods： We proposed two structurally different methods to identify HPs： predefined thresholding-based one （static one）, and statistical thresholding-based technique （dynamic one）. In the first method, 3 different thresholds were used： 5%, 10%, and 20%. Next, it was aimed to assess how delineated HPs were spatially matched to satellite data with coarse spatial resolution. Selected cell sizes were 25, 50, 100, 250, and 500 m. The number of particular grid cells which almost entirely fell into registered HPs was counted （leaving 2% cell area tolerance level）. This procedure was executed separately for each variant and selected structural variables, as well as for their intersection parts. Results： The results of this investigation revealed that ALS data might have the potential in the identification of HPs of forest stands. We showed that different ALS based variables and thresholds of HPs definition influenced areas which can be treated as similar and homogeneous. We proved that integration of more than one structural variable limits size of the HPs, in contrast, visual interpretation revealed that inside such patches vegetation structure is more constant. Conclusions： We concluded that ALS data can be used as a potential source of data to ＂enlarge＂ small ground sample plots and to be used for evaluation and calibration of remotely sensed datasets provided by global systems with coarse spatial resolutions.
基金Supported by the National Natural Science Foundation of China under Grant(60921063)the National Program on Key Basic Research Project(973Program)(2010CB327400)the National Science and Technology Major Project(2010ZX03007-002-01)~~
文摘The microstrip dual-mode filter （DMF） with conventional coupling structure has some limitations in- eluding the port coupling strength limited by fabrication tolerance and the existence of serious second order spuri- ous band. Therefore, a novel DMF with a offset-feed bended coupling structure and a stepped-impedance dual- mode resonator is proposed for coupling enhancement and spurious response suppression. Based on the analysis of the change of spur frequencies and the current distribution of spur resonant modes, all spurs near passband of the cascaded DMF can be fully suppressed by optimizing the structure parameters of parasite resonators, which bene- fits from the inherent well-controlled transmission zeros. Experimental results show that the proposed DMF ex- hibits lower insertion loss ,much sharper rate of cutoff and wider spur-free stop band compared with conventional DMF. This design is applicable for spur suppression in wideband communication.
文摘Autonomous Underwater Vehicles （AUVs） are capable of conducting various underwater missions and marine tasks over long periods of time. In this study, a novel conflict-free motion-planning framework is introduced. This framework enhances AUV mission performance by completing the maximum number of highest priority tasks in a limited time through a large-scale waypoint cluttered operating field and ensuring safe deployment during the mission. The proposed combinatorial route-path-planner model takes advantage of the Biogeography- Based Optimization （BBO） algorithm to satisfy the objectives of both higher- and lower-level motion planners and guarantee the maximization of mission productivity for a single vehicle operation. The performance of the model is investigated under different scenarios, including cost constraints in time-varying operating fields. To demonstrate the reliability of the proposed model, the performance of each motion planner is separately assessed and statistical analysis is conducted to evaluate the total performance of the entire model. The simulation results indicate the stability of the proposed model and the feasibility of its application to real-time experiments.
基金Supported by the National Natural Science Foundation of China(40436015)The assessment study of the KuaFu mission was supported by the National Natural Science Foun-dation of ChinaCanadian work on the KuaFu project is supported by the Canadian Space Agency under the“Ravens Concept Study”
文摘The KuaFu mission-Space Storms,Aurora and Space Weather Explorer-is an"L1+Polar"triple satellite project composed of three spacecraft:KuaFu-A will be located at L1 and have instruments to observe solar EUV and FUV emissions,and white-light Coronal Mass Ejections(CMEs),and to measure radio waves,the local plasma and magnetic field,and high-energy particles.KuaFuB1 and KuaFu-B2 will bein polar orbits chosen to facilitate continuous 24 hours a day observation of the north polar Aurora Oval.The KuaFu mission is designed to observe the complete chain of disturbances from the solar atmosphere to geospace,including solar flares,CMEs,interplanetary clouds,shock waves,and their geo-effects,such as magnetospheric sub-storms and magnetic storms,and auroral activities.The mission may start at the next solar maximum(launch in about 2012),and with an initial mission lifetime of two to three years.KuaFu data will be used for the scientific study of space weather phenomena,and will be used for space weather monitoring and forecast purposes.The overall mission design,instrument complement,and incorporation of recent technologies will target new fundamental science,advance our understanding of the physical processes underlying space weather,and raise the standard of end-to-end monitoring of the Sun-Earth system.
文摘SMESE (SMall Explorer For the study of Solar Eruptions) is a Franco-Chinese Microsatellite mission. The scientific objectives of SMESE are the study of coronal mass ejections and flares. Its payload consists of three instrument packages: LYOT, DESIR and HEBS. LYOT is com-posed of a Ly-α (121.6 nm) coronagraph, a Ly-α disk imager and a far UV disk imager. DESIR is an infrared telescope working at 35μm and 150μm. HEBS is a high energy burst spectrometer working in X-rays and γ-rays covering the 10keV to 600 MeV range. SMESE will be launched around 2011, providing a unique opportunity of detecting and understanding eruptions at the maximum activity phase of the solar cycle in a wide range of energies.
文摘The majority of allied casualties from recent conflicts were caused by blast wave and fragments perforation damage from Improvised Explosive Devices. Survivability to this type of threat is a critical factor to consider for land platform design. This paper proposes an original approach to platform survivability assessment using a combination of Agent-Based(AB) simulation and Fault Tree Analysis(FTA) to predict the consequences of IED fragment impacts on the platform operational status. As a demonstration, this approach is applied to the comparison of different platform architectures to gain insight into the optimisation of the platform component topology.
基金Supported by National Key R&D Program of China(2018YFC1503501)Research Grant from Institute of Crustal Dynamics,China Earthquake Administration(ZDJ2019-22 and ZDJ2020-06)the APSCO Earthquake Research Project PhaseⅡ。
文摘The CSES(China Seismo-Electromagnetic Satellite)is the electromagnetism satellite of China’s Zhangheng mission which is planned to launch a series of microsatellites within next 10 years in order to monitor the electromagnetic environment,gravitational field.The CSES 01 probe(also called ZH-1)was launched successfully on 2 February 2018,from the Jiuquan Satellite Launch Centre(China)and is expected to operate for 5 years in orbit.The second probe CSES 02 is going to be launched in 2022.The scientific objectives of CSES are to detect the electromagnetic field and waves,plasma and particles,for studying the seismic-associated disturbances.To meet the requirements of scientific objective,the satellite is designed to be in a sun-synchronous orbit with a high inclination of 97.4°at an altitude around 507 km.CSES carries nine scientific payloads including Search-coil magnetometer,Electric Field Detector,High precision Magnetometer,GNSS occultation Receiver,Plasma Analyzer,Langmuir Probe,two Energetic Particle Detectors(including an Italian one),and Tri-Band Transmitter.Up to now,CSES has been operating in orbit for 2 years with stable and reliable performance.By using all kinds of data acquired by CSES,we have undertaken a series of scientific researches in the field of global geomagnetic field re-building,the ionospheric variation environment,waves,and particle precipitations under disturbed space weather and earthquake activities,the Lithosphere-Atmosphere-Ionosphere coupling mechanism research and so on.
基金supported in part by the National Key Research and Development Program of China (Grant No. 2020YFC2201501)the National Natural Science Foundation of China (Grant No. 12147103, special fund to the center for quanta-to-cosmos theoretical physics) (Grant No. 11821505)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB23030100)the Chinese Academy of Sciences (CAS)。
文摘In space-based gravitational wave detection, the estimation of far-field wavefront error of the distorted beam is the precondition for the noise reduction. Zernike polynomials are used to describe the wavefront error of the transmitted distorted beam. The propagation of a laser beam between two telescope apertures is calculated numerically. Far-field wavefront error is estimated with the absolute height of the peak-to-valley phase deviation between the distorted Gaussian beam and a reference distortion-free Gaussian beam. The results show that the pointing jitter is strongly related to the wavefront error. Furthermore, when the jitter decreases 10 times from 100 nrad to 10 nrad, the wavefront error reduces for more than an order of magnitude. In the analysis of multi-parameter minimization, the minimum of wavefront error tends to Z[5,3] Zernike in some parameter ranges. Some Zernikes have a strong correlation with the wavefront error of the received beam. When the aperture diameter increases at Z[5,3] Zernike, the wavefront error is not monotonic and has oscillation.Nevertheless, the wavefront error almost remains constant with the arm length increasing from 10-1Mkm to 10~3Mkm.When the arm length decreases for three orders of magnitude from 10-1Mkm to 10-4Mkm, the wavefront error has only an order of magnitude increasing. In the range of 10-4Mkm to 10~3Mkm, the lowest limit of the wavefront error is from 0.5 fm to 0.015 fm at Z[5,3] Zernike and 10 nrad jitter.
文摘In the wake of the rapid economy and society development, phenomena such as industri-alisation, urbanisation, marketisation and the ageing of the population have shown an accelerating trend. As a result, mental health issues due to these phenomena are increasingly serious, making mental health both concerning public health and societal issues that have a great impact on economic and social development.^1 In 2014, there were 16 million persons with severe mental disor-ders in China.
基金Supported by the Major Program of the National Science Foundation of China(41590851)the Beijing Municipal Science and Technology Commission(Z181100002918003)。
文摘China’s first Mars exploration mission is scheduled to be launched in 2020.It aims not only to conduct global and comprehensive exploration of Mars by use of an orbiter but also to carry out in situ observation of key sites on Mars with a rover.This mission focuses on the following studies:topography,geomorphology,geological structure,soil characteristics,water-ice distribution,material composition,atmosphere and ionosphere,surface climate,environmental characteristics,Mars internal structure,and Martian magnetic field.It is comprised of an orbiter,a lander,and a rover equipped with 13 scientific payloads.This article will give an introduction to the mission including mission plan,scientific objectives,scientific payloads,and its recent development progress.
文摘Considering the bad condition and shortage of medical resource in Sudan peacekeeping mission area, the author contrives the procedure of CASEVAC/MEDEVAC, including definition, request, authorization, operation and miscellaneous, and stipulates the responsibility of parties concerned. The aim is to ensure systematic, organized and timely evacuation of patients to the most suitable medical facility for each individual case,thereby to minimize the loss of lives and limbs.
基金the Strategic Priority Research Program of Chinese Academy of Sciences(XDA17010301)。
文摘Space radiation has been identified as the main health hazard to crews involved in manned Mars missions.Active shielding is more effective than passive shielding to the very energetic particles from cosmic rays.Particle motion in a magnetic field is studied based on the single-particle theory and Monte Carlo method.By comparing the shielding efficiency of different magnetic field configurations,a novel active magnetic shielding configuration with lower mass cost and power consumption is proposed for manned Mars missions.The new magnetic configuration can shield 92.8%of protons and 84.4%of alpha particles with E<4 GeV·n^(-1),when considering the passive shielding contribution of 10.0 g·cm^(-2) Al Shielding,the required magnetic stiffness can be reduced from 27 Tm to 16 Tm.The detailed analysis of mass cost and power consumption shows that active shielding will be a promising means to protect crews from space radiation exposure in manned Mars missions.
