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
Transmission electron microscopy(TEM)is an important tool for structure characterization of zeolite materials.Structural information can be obtained by different TEM techniques,for example electron diffraction(ED),hig...Transmission electron microscopy(TEM)is an important tool for structure characterization of zeolite materials.Structural information can be obtained by different TEM techniques,for example electron diffraction(ED),high-resolution transmission electron microscopy(HRTEM),scanning transmission electron microscopy(STEM)and electron tomography(ET),each with its own advantages and limitations.These techniques are briefly introduced.Examples are given to show how these techniques can be used to solve various structure-related problems in zeolites.With this review we will describe the basic principles of transmission electron microscopy techniques for structural characterization,including recent methodological advancements.Advantages as well as challenges of using TEM for structural characterization will be described in relation to other methods.Examples of structural characterization of zeolites will be given for each of the methods.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 Swedish Research Council(VR,No.2017-0432)the Swedish Governmental Agency for Innovation Systems(VINNOVA)+1 种基金the Knut&Alice Wallenberg Foundation through the project grant 3DEM-NATURThe EM facility was supported by the Knut and Alice Wallenberg Foundation.TW acknowledges the Swedish Research Council(VR)for an International Postdoc grant(2014-06948).
文摘Transmission electron microscopy(TEM)is an important tool for structure characterization of zeolite materials.Structural information can be obtained by different TEM techniques,for example electron diffraction(ED),high-resolution transmission electron microscopy(HRTEM),scanning transmission electron microscopy(STEM)and electron tomography(ET),each with its own advantages and limitations.These techniques are briefly introduced.Examples are given to show how these techniques can be used to solve various structure-related problems in zeolites.With this review we will describe the basic principles of transmission electron microscopy techniques for structural characterization,including recent methodological advancements.Advantages as well as challenges of using TEM for structural characterization will be described in relation to other methods.Examples of structural characterization of zeolites will be given for each of the methods.
