The Lobster Eye Imager for Astronomy(LEIA),a pathfinder of the Wide-field X-ray Telescope of the Einstein Probe mission,was successfully launched onboard the SATech-01 satellite of the Chinese Academy of Sciences on20...The Lobster Eye Imager for Astronomy(LEIA),a pathfinder of the Wide-field X-ray Telescope of the Einstein Probe mission,was successfully launched onboard the SATech-01 satellite of the Chinese Academy of Sciences on2022 July 27.In this paper,we introduce the design and on-ground test results of the LEIA instrument.Using stateof-the-art Micro-Pore Optics(MPO),a wide field of view of 346 square degrees(18.6°×18.6°)of the X-ray imager is realized.An optical assembly composed of 36 MPO chips is used to focus incident X-ray photons,and four large-format complementary metal-oxide semiconductor(CMOS)sensors,each of size 6 cm×6 cm,are used as the focal plane detectors.The instrument has an angular resolution of 4’-8’(in terms of FWHM)for the central focal spot of the point-spread function,and an effective area of 2-3 cm^(2) at 1 keV in essentially all the directions within the field of view.The detection passband is 0.5-4 keV in soft X-rays and the sensitivity is2-3×10^(-11) erg s^(-1) cm^(-2)(about 1 milliCrab)with a 1000 s observation.The total weight of LEIA is 56 kg and the power is 85 W.The satellite,with a design lifetime of 2 yr,operates in a Sun-synchronous orbit of 500 km with an orbital period of 95 minutes.LEIA is paving the way for future missions by verifying in flight the technologies of both novel focusing imaging optics and CMOS sensors for X-ray observation,and by optimizing the working setups of the instrumental parameters.In addition,LEIA is able to carry out scientific observations to find new transients and to monitor known sources in the soft X-ray band,albeit with limited useful observing time available.展开更多
At present,most total knee replacement(TKR)prostheses on the market are designed according to the sizes of Caucasians.However,extensive studies have indicated that human anatomies differ among different ethnicities.A ...At present,most total knee replacement(TKR)prostheses on the market are designed according to the sizes of Caucasians.However,extensive studies have indicated that human anatomies differ among different ethnicities.A number of reports have indicated that Chinese TKR patients do not match with available prostheses.In this study,computed tomography(CT)images of 52 knees of Chinese men and women were used for anthropometric measurements.Index and geometric measurements were definedand used for correlation analysis.Key parameters from the measurement results were identified.Detailed geometries of knees were measured as coordinates.A deformable three-dimensional(3D)knee modelbased on anatomical coordinates correlating with the identified key parameters was generated.A pros-thesis was then designed according to the analyzed results.Surface matching analysis,bone resectionanalysis,and cadaveric trials were conducted and compared with commercial products to validate theproposed design.The femoral component designed by this study resulted in the highest accuracy(rootmean square point-to-surface(RMS PS),(1.08±0.20)mm)and lowest amount of resected bone volume(27412mm^(3))in comparison with two commercial knee prostheses.This study suggests a new approachfor population-based patient-specific femoral prosthesis design With a single,easilty acquired dimen-sion-namely,epicondyle width(ECW)-as input,a patient-specific femoral prosthesis can be designed according to the analyzed measured data and manufactured by additive manufacturing(AM)methods.Meanwhile,the reconstructed femoral condylar surface was compared with the femoral condylar surfacein the original CT scanning data The average RMS PS distance of the reconstructed femoral condylar surface among all data was(1.10±0.18)mm,which is comparable to other statistical shape modeling methods using multiple radiographs as input data.There is a need to develop an anthropometric-based knee prosthesis for the Chinese population.Based on the anthropometry of the Chinese population,our new design fits Chinese patients better and reserves more bone volume compared with current commercial prostheses,which is an essential step toward AM for personalized knee prostheses.展开更多
基金supported by the Einstein Probe project,a mission in the Strategic Priority Program on Space Science of CAS(grant Nos.XDA15310000,XDA15052100)in part been supported by the European Union’s Horizon 2020 Program under the AHEAD2020 project(grant No.871158).
文摘The Lobster Eye Imager for Astronomy(LEIA),a pathfinder of the Wide-field X-ray Telescope of the Einstein Probe mission,was successfully launched onboard the SATech-01 satellite of the Chinese Academy of Sciences on2022 July 27.In this paper,we introduce the design and on-ground test results of the LEIA instrument.Using stateof-the-art Micro-Pore Optics(MPO),a wide field of view of 346 square degrees(18.6°×18.6°)of the X-ray imager is realized.An optical assembly composed of 36 MPO chips is used to focus incident X-ray photons,and four large-format complementary metal-oxide semiconductor(CMOS)sensors,each of size 6 cm×6 cm,are used as the focal plane detectors.The instrument has an angular resolution of 4’-8’(in terms of FWHM)for the central focal spot of the point-spread function,and an effective area of 2-3 cm^(2) at 1 keV in essentially all the directions within the field of view.The detection passband is 0.5-4 keV in soft X-rays and the sensitivity is2-3×10^(-11) erg s^(-1) cm^(-2)(about 1 milliCrab)with a 1000 s observation.The total weight of LEIA is 56 kg and the power is 85 W.The satellite,with a design lifetime of 2 yr,operates in a Sun-synchronous orbit of 500 km with an orbital period of 95 minutes.LEIA is paving the way for future missions by verifying in flight the technologies of both novel focusing imaging optics and CMOS sensors for X-ray observation,and by optimizing the working setups of the instrumental parameters.In addition,LEIA is able to carry out scientific observations to find new transients and to monitor known sources in the soft X-ray band,albeit with limited useful observing time available.
文摘At present,most total knee replacement(TKR)prostheses on the market are designed according to the sizes of Caucasians.However,extensive studies have indicated that human anatomies differ among different ethnicities.A number of reports have indicated that Chinese TKR patients do not match with available prostheses.In this study,computed tomography(CT)images of 52 knees of Chinese men and women were used for anthropometric measurements.Index and geometric measurements were definedand used for correlation analysis.Key parameters from the measurement results were identified.Detailed geometries of knees were measured as coordinates.A deformable three-dimensional(3D)knee modelbased on anatomical coordinates correlating with the identified key parameters was generated.A pros-thesis was then designed according to the analyzed results.Surface matching analysis,bone resectionanalysis,and cadaveric trials were conducted and compared with commercial products to validate theproposed design.The femoral component designed by this study resulted in the highest accuracy(rootmean square point-to-surface(RMS PS),(1.08±0.20)mm)and lowest amount of resected bone volume(27412mm^(3))in comparison with two commercial knee prostheses.This study suggests a new approachfor population-based patient-specific femoral prosthesis design With a single,easilty acquired dimen-sion-namely,epicondyle width(ECW)-as input,a patient-specific femoral prosthesis can be designed according to the analyzed measured data and manufactured by additive manufacturing(AM)methods.Meanwhile,the reconstructed femoral condylar surface was compared with the femoral condylar surfacein the original CT scanning data The average RMS PS distance of the reconstructed femoral condylar surface among all data was(1.10±0.18)mm,which is comparable to other statistical shape modeling methods using multiple radiographs as input data.There is a need to develop an anthropometric-based knee prosthesis for the Chinese population.Based on the anthropometry of the Chinese population,our new design fits Chinese patients better and reserves more bone volume compared with current commercial prostheses,which is an essential step toward AM for personalized knee prostheses.
