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
In this study,a novel solid-state alloying approach was adopted to fabricate Al-Mg alloys with high Mg contents(C_(Mg)) by accumulative roll-bonding(ARB)of Al and Mg elemental materials to ultrahigh cycles.Experimenta...In this study,a novel solid-state alloying approach was adopted to fabricate Al-Mg alloys with high Mg contents(C_(Mg)) by accumulative roll-bonding(ARB)of Al and Mg elemental materials to ultrahigh cycles.Experimental results showed that the degree of alloying increased with the increase of ARB cycles and a supersaturatedα-Al solid solution accompanied with nanoprecipitates was formed in the Al-Mg alloys by ARB to 70 cycles.The as-prepared Al-Mg alloys exhibited enhanced mechanical properties,with a maximum tensile strength of∼615 MPa and a tensile elongation of∼10%at C_(Mg)=13 wt.%.The high strength can be attributed to different mechanisms,namely solid solution strengthening,grain boundary strengthening,dislocation strengthening,and precipitation strengthening.The Al-Mg alloys showed increased work hardening with increasing C_(Mg),due to the enhanced formation of nanoprecipitates.Meanwhile,no obvious drop in the intergranular corrosion(IGC)resistance was found in the Al-Mg alloys with C_(Mg) up to 13 wt.%.Moreover,sensitization treatment was found to induce little decrease in the IGC resistance of the Al-Mg alloys with C_(Mg)≤13 wt.%.We found that the excellent IGC resistance was due to the suppression of grain boundary precipitation by the preferred formation of precipitates within the grains that were induced by ARB.Our study indicated the novelty of the present solid-state alloying approach to achieving a superior combination of high mechanical properties and IGC resistance in Al-Mg alloys.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.
基金supported by the National Natural Science Foundation of China(Nos.52175358 and 51371128)。
文摘In this study,a novel solid-state alloying approach was adopted to fabricate Al-Mg alloys with high Mg contents(C_(Mg)) by accumulative roll-bonding(ARB)of Al and Mg elemental materials to ultrahigh cycles.Experimental results showed that the degree of alloying increased with the increase of ARB cycles and a supersaturatedα-Al solid solution accompanied with nanoprecipitates was formed in the Al-Mg alloys by ARB to 70 cycles.The as-prepared Al-Mg alloys exhibited enhanced mechanical properties,with a maximum tensile strength of∼615 MPa and a tensile elongation of∼10%at C_(Mg)=13 wt.%.The high strength can be attributed to different mechanisms,namely solid solution strengthening,grain boundary strengthening,dislocation strengthening,and precipitation strengthening.The Al-Mg alloys showed increased work hardening with increasing C_(Mg),due to the enhanced formation of nanoprecipitates.Meanwhile,no obvious drop in the intergranular corrosion(IGC)resistance was found in the Al-Mg alloys with C_(Mg) up to 13 wt.%.Moreover,sensitization treatment was found to induce little decrease in the IGC resistance of the Al-Mg alloys with C_(Mg)≤13 wt.%.We found that the excellent IGC resistance was due to the suppression of grain boundary precipitation by the preferred formation of precipitates within the grains that were induced by ARB.Our study indicated the novelty of the present solid-state alloying approach to achieving a superior combination of high mechanical properties and IGC resistance in Al-Mg alloys.
