Helium-3(3He) implanted by solar wind in the lunar regolith is a valuable resource because of its potential as a fusion fuel.On the basis of the Apollo regolith samples,a linear relationship between 3He abundance and ...Helium-3(3He) implanted by solar wind in the lunar regolith is a valuable resource because of its potential as a fusion fuel.On the basis of the Apollo regolith samples,a linear relationship between 3He abundance and solar wind flux,optical maturity and TiO2 content has been presented.China successfully launched its first lunar exploration satellite Chang-E 1(CE-1) on October 24,2007.A multi-channeled microwave radiometer was aboard the satellite with the purpose of measuring microwave thermal emission from the lunar surface layer.From the multi-channel brightness temperature(Tb) observed by CE-1,the global distribution of the regolith thickness was inverted from the multi-channel Tb,and was used to evaluate the total amount of 3He per unit area in the lunar regolith.The global inventory of 3He was estimated as being 6.6×108 kg;3.7×108 kg for the lunar nearside and 2.9×108 kg for the lunar farside.展开更多
A SIMO(single input and multiple output) system of a step-frequency(SF) radar is used.It works in downward-looking spotlight mode and moves within a 2D synthetic plane array.A 3D(three-dimensional) matrix of bistatic ...A SIMO(single input and multiple output) system of a step-frequency(SF) radar is used.It works in downward-looking spotlight mode and moves within a 2D synthetic plane array.A 3D(three-dimensional) matrix of bistatic scattering fields is produced in both the amplitude and phase from a 3D complex-shaped electric-large target above background surface.In numerical simulation,the bidirectional analytic ray tracing(BART) method is applied to calculate bistatic scattering in the SIMO observations from a volumetric target above background rough surface.An improved 3D RMA(range migration algorithm) is then utilized to make the imaging.Its 3D imaging is applied to reconstruct the target profile.As validation and comparison,the scattering fields of some simple targets are computed with comparisons of the BART and FEKO software.The SIMO techniques of imaging and reconstruction for a 3D target,such as a tank-like model over rough surface,are presented.展开更多
A fast iterative approach of generalized forward-backward method with the spectrum acceleration algorithm (GFBM/SAA) is developed for solving electromagnetic field integral equation and is applied to numerical simulat...A fast iterative approach of generalized forward-backward method with the spectrum acceleration algorithm (GFBM/SAA) is developed for solving electromagnetic field integral equation and is applied to numerical simulation of radar surveillance of the ship target in oceanic clutters. Randomly rough surface is realized by the Monte Carlo method using the Pierson-Moskowitz spectrum. Numerical results of bistatic and back-scattering from the ship target and oceanic clutters demonstrate the functional dependencies upon the situation of radar surveillance such as the incidence and observation angles, radar altitude, ship RCS and other oceanic conditions.展开更多
基金supported in part by the National Natural Science Foundation of China (60971091,41071219)the State Key Laboratory of Remote Sensing Science (2009KFJJ011)
文摘Helium-3(3He) implanted by solar wind in the lunar regolith is a valuable resource because of its potential as a fusion fuel.On the basis of the Apollo regolith samples,a linear relationship between 3He abundance and solar wind flux,optical maturity and TiO2 content has been presented.China successfully launched its first lunar exploration satellite Chang-E 1(CE-1) on October 24,2007.A multi-channeled microwave radiometer was aboard the satellite with the purpose of measuring microwave thermal emission from the lunar surface layer.From the multi-channel brightness temperature(Tb) observed by CE-1,the global distribution of the regolith thickness was inverted from the multi-channel Tb,and was used to evaluate the total amount of 3He per unit area in the lunar regolith.The global inventory of 3He was estimated as being 6.6×108 kg;3.7×108 kg for the lunar nearside and 2.9×108 kg for the lunar farside.
基金supported by the National Natural Science of Foundation of China (Grant Nos. 60971091 and 41071219)
文摘A SIMO(single input and multiple output) system of a step-frequency(SF) radar is used.It works in downward-looking spotlight mode and moves within a 2D synthetic plane array.A 3D(three-dimensional) matrix of bistatic scattering fields is produced in both the amplitude and phase from a 3D complex-shaped electric-large target above background surface.In numerical simulation,the bidirectional analytic ray tracing(BART) method is applied to calculate bistatic scattering in the SIMO observations from a volumetric target above background rough surface.An improved 3D RMA(range migration algorithm) is then utilized to make the imaging.Its 3D imaging is applied to reconstruct the target profile.As validation and comparison,the scattering fields of some simple targets are computed with comparisons of the BART and FEKO software.The SIMO techniques of imaging and reconstruction for a 3D target,such as a tank-like model over rough surface,are presented.
基金This work was supported by the China State Key Basic Research Project (Grant No. 2001CB309405) and the National Natural Science Foundation of China (Grant Nos. 49831060 and 6012009).
文摘A fast iterative approach of generalized forward-backward method with the spectrum acceleration algorithm (GFBM/SAA) is developed for solving electromagnetic field integral equation and is applied to numerical simulation of radar surveillance of the ship target in oceanic clutters. Randomly rough surface is realized by the Monte Carlo method using the Pierson-Moskowitz spectrum. Numerical results of bistatic and back-scattering from the ship target and oceanic clutters demonstrate the functional dependencies upon the situation of radar surveillance such as the incidence and observation angles, radar altitude, ship RCS and other oceanic conditions.
