The COVID-19 is a major global health event that has changed people’s lives and behaviors. As a fragile and sensitive area with high population density and poor living conditions in the city, collective housing is al...The COVID-19 is a major global health event that has changed people’s lives and behaviors. As a fragile and sensitive area with high population density and poor living conditions in the city, collective housing is also an important construction area for future urban renewal. In the process of the spread of the new crown epidemic, the collective housing has exposed a series of weaknesses such as difficult community management, inconvenience of life, and insufficient outdoor space. Therefore, the update and transformation of the outdoor environment of the collective housing combined with the concept of public health is a problem that must be considered at present. This article combines the practice of renewal and transformation of the X community in Chaoyang District, Beijing, combined with survey methods such as questionnaires, interviews, and observations, combined with the needs of residents and the practical experience of the grassroots management unit, and carried out an overall renewal design of the external space environment of the collective housing. The epidemic is combined with the division of functional layout, refined design of outdoor activity space to ensure safe distance, and increased shared smart facilities to improve the quality of the outdoor environment of collective residences and strengthen community resilience;to achieve communication and sharing, epidemic prevention and control on the basis of ensuring safe social distance outdoor sports and other functions. In this way, the ability of collective housing to prevent, identify, and dispose of urban risks will be improved, and will provide residents with a better and livable community life.展开更多
Background The Gas Pixel Detector(GPD)is a key part of the Polarimetry Focusing Array(PFA)sub-system onboard the enhance X-ray Timing and Polarimetry mission(eXTP).The GPD can accurately provide the polarized angle an...Background The Gas Pixel Detector(GPD)is a key part of the Polarimetry Focusing Array(PFA)sub-system onboard the enhance X-ray Timing and Polarimetry mission(eXTP).The GPD can accurately provide the polarized angle and degree for incoming soft X-rays(requirements of minimum detectable polarization<1%(10^(6) s,1 mCrab))from celestial objects under extreme conditions of density,gravity and magnetism.Purpose Paste the GPD chips on a matched ceramic package is one of the most important procedures for the GPD assembly,and the parallelism between the top surface of an ASIC chip and the bottom surface of a Gas Electron Multiplier(GEM)foil can have impact on the distribution of electric field within transfer region and reconstruction of photoelectric trajectories,resulting in deterioration of the GPD sensitivity.This study quantifies the influence and gives a reasonable expectation of the parallelism.Methods A simulation framework of the GPD is constructed to quantify the influence on the GPD performance and values of the parallelism are measured by a gauge with a position resolution of o.1μm.Results:The difference of degree of modulation is less than 1% comparing the parallelism with a value of 20μm to a value of 0μm in response to both polarized and unpolarized X-rays.Meanwhile,the value of parallelism can reach 6.9±3.4μm(0.0176°±0.0087°)by testing and verifying.Conclusions The impact on the GPD performance can be less than 1%as the parallelism with an order of 20μm,and we also give a reasonable measuring method and verify the controllability and feasibility of the parallelism with an order of 20μm for pasting the ASIC chip on the surface of a ceramic package.展开更多
Background Accurate preoperative evaluation of the levator palpebrae superioris(LPS)strength is required for specific calculation of anterior migration or shortening.This information serves as a surgical reference for...Background Accurate preoperative evaluation of the levator palpebrae superioris(LPS)strength is required for specific calculation of anterior migration or shortening.This information serves as a surgical reference for more accurate correction of ptosis.Methods Between June 2017 and June 2019,155 eyes of 97 patients were studied.Patients were divided into the following 3 groups based on the ptosis degree:mild(28 cases),moderate(53 cases),and severe(16 cases).The LPS strength was evaluated preoperatively and used to calculate LPS anterior migration and shortening.The LPS aponeurosis and Müller’s muscle(L-M)complex was separated from the upper margin of the tarsal plate to the calculated height according to the levator muscle suspension system retention approach.The complex was subsequently fixed to the planned tarsal plate location.The upper eyelid margin(UEM)height,eyelid morphology,eyelid closure,eye symmetry,exposure keratitis status,and patient satisfaction were evaluated at 1 week and at 1 and 6 months postoperatively.Results In all cases,the UEM positions were normal,and only patients with severe ptosis exhibited lagophthalmos in the early posterative period.Six months postoperatively,13%of eyes in the severe group had residual ptosis;all mild and moderate cases exhibited good surgical outcomes.The eyelids closed well with no exposure keratitis.All patients were satisfied with the eyelid contour.Conclusions Accurate LPS anterior migration and aponeurosis shortening can eliminate various factors affecting surgical blepharoptosis treatment.These procedures not only reduce operation time but also enhance the stability of postoperative correction.展开更多
Blepharoptosis is a symptom that is commonly observed in clinics.It presents with drooping of the upper eyelid and an asymmetric appearance of the eye.It can occur because of various causes.If left untreated,severe co...Blepharoptosis is a symptom that is commonly observed in clinics.It presents with drooping of the upper eyelid and an asymmetric appearance of the eye.It can occur because of various causes.If left untreated,severe congenital blepharoptosis may impair visual function.The surgical approach largely depends on the severity of blepharoptosis,Bell’s phenomenon,and surgical history.However,it is intricate and difficult to achieve satisfactory symmetry and avoid complications.Owing to the complexity involved and discrepancies in treatment,we planned to arrive at a consensus on the diagnosis and correction of blepharoptosis among Chinese plastic surgeons and ophthalmologists,aiming to establish more standardized treatments and cause less harm to patients.展开更多
Melatonin receptor 1B(MT2,encoded by the MTNR1B gene),a high-affinity receptor for melatonin,is associated with glucose homeostasis including glucose uptake and transport.The rs10830963 variant in the MTNR1B gene is l...Melatonin receptor 1B(MT2,encoded by the MTNR1B gene),a high-affinity receptor for melatonin,is associated with glucose homeostasis including glucose uptake and transport.The rs10830963 variant in the MTNR1B gene is linked to glucose metabolism disorders including gestational diabetes mellitus(GDM);however,the relationship between MT2-mediated melatonin signaling and a high birth weight of GDM infants from maternal glucose abnormality remains poorly understood.This article aims to investigate the relationship between rs10830963 variants and GDM development,as well as the effects of MT2 receptor on glucose uptake and transport in trophoblasts.TaqMan-MGB(minor groove binder)probe quantitative realtime polymerase chain reaction(qPCR)assays were used for rs10930963 genotyping.MT2 expression in the placenta of GDM and normal pregnant women was detected by immunofluorescence,western blot,and qPCR.The relationship between MT2 and glucose transporters(GLUTs)or peroxisome proliferator-activated receptorγ(PPARγ)was established by western blot,and glucose consumption of trophoblasts was measured by a glucose assay kit.The results showed that the genotype and allele frequencies of rs10830963 were significantly different between GDM and normal pregnant women(P<0.05).The fasting,1-h and 2-h plasma glucose levels of G-allele carriers were significantly higher than those of C-allele carriers(P<0.05).Besides,the protein and messenger RNA(mRNA)expression of MT2 in the placenta of GDM was significantly higher than that of normal pregnant women(P<0.05).Melatonin could stimulate glucose uptake and GLUT4 and PPARγprotein expression in trophoblasts,which could be attenuated by MT2 receptor knockdown.In conclusion,the rs10830963 variant was associated with an increased risk of GDM.The MT2 receptor is essential for melatonin to raise glucose uptake and transport,which may be mediated by PPARγ.展开更多
Introduction The medium-energy X-ray telescope(ME)is a collimated X-ray telescope onboard the Insight hard X-ray modulation telescope(Insight-HXMT)satellite.It has 1728 Si-PIN pixels readout using 54 low noise applica...Introduction The medium-energy X-ray telescope(ME)is a collimated X-ray telescope onboard the Insight hard X-ray modulation telescope(Insight-HXMT)satellite.It has 1728 Si-PIN pixels readout using 54 low noise application-specific integrated circuits(ASICs).ME covers the energy range of 5–30 keV and has a total detection area of 952cm2.The typical energy resolution of ME at the beginning of the mission is 3 keV at 17.8 keV(full width at half maximum,FWHM),and the time resolution is 255μs.In this study,we present the in-orbit performance of ME in its first 5 years of operation.Methods The performance of ME was monitored using onboard radioactive sources and astronomical X-ray objects.ME carries six 241Am radioactive sources for onboard calibration,which can continuously illuminate the calibration pixels.The long-term performance evolution of ME can be quantified using the properties of the accumulated spectra of the calibration pixels.In addition,observations of the Crab Nebula and the pulsar were used to check the long-term evolution of the detection efficiency as a function of energy.Conclusion After 5 years of operation,742cm2 of the Si-PIN pixelswere stillworking normally.The peak positions of 241Am emission lines gradually shifted to the high-energy region,implying a slow increase in ME gain of 1.43%.A comparison of the ME spectra of the Crab Nebula and the pulsar shows that the E–C relations and the redistribution matrix file are still acceptable for most data analysis works,and there is no detectable variation in the detection efficiency.展开更多
Finding the electromagnetic(EM) counterpart of binary compact star merger, especially the binary neutron star(BNS) merger,is critically important for gravitational wave(GW) astronomy, cosmology and fundamental physics...Finding the electromagnetic(EM) counterpart of binary compact star merger, especially the binary neutron star(BNS) merger,is critically important for gravitational wave(GW) astronomy, cosmology and fundamental physics. On Aug. 17, 2017,Advanced LIGO and Fermi/GBM independently triggered the first BNS merger, GW170817, and its high energy EM counterpart,GRB 170817 A, respectively, resulting in a global observation campaign covering gamma-ray, X-ray, UV, optical, IR, radio as well as neutrinos. The High Energy X-ray telescope(HE) onboard Insight-HXMT(Hard X-ray Modulation Telescope) is the unique high-energy gamma-ray telescope that monitored the entire GW localization area and especially the optical counterpart(SSS17 a/AT2017 gfo) with very large collection area(~1000 cm^2) and microsecond time resolution in 0.2-5 MeV. In addition,Insight-HXMT quickly implemented a Target of Opportunity(ToO) observation to scan the GW localization area for potential X-ray emission from the GW source. Although Insight-HXMT did not detect any significant high energy(0.2-5 MeV) radiation from GW170817, its observation helped to confirm the unexpected weak and soft nature of GRB 170817 A. Meanwhile,Insight-HXMT/HE provides one of the most stringent constraints(~10^(-7) to 10^(-6) erg/cm^2/s) for both GRB170817 A and any other possible precursor or extended emissions in 0.2-5 MeV, which help us to better understand the properties of EM radiation from this BNS merger. Therefore the observation of Insight-HXMT constitutes an important chapter in the full context of multi-wavelength and multi-messenger observation of this historical GW event.展开更多
In this paper we present the enhanced X-ray Timing and Polarimetry mission—eXTP. eXTP is a space science mission designed to study fundamental physics under extreme conditions of density, gravity and magnetism. The m...In this paper we present the enhanced X-ray Timing and Polarimetry mission—eXTP. eXTP is a space science mission designed to study fundamental physics under extreme conditions of density, gravity and magnetism. The mission aims at determining the equation of state of matter at supra-nuclear density, measuring effects of QED, and understanding the dynamics of matter in strong-field gravity. In addition to investigating fundamental physics, eXTP will be a very powerful observatory for astrophysics that will provide observations of unprecedented quality on a variety of galactic and extragalactic objects. In particular, its wide field monitoring capabilities will be highly instrumental to detect the electro-magnetic counterparts of gravitational wave sources.The paper provides a detailed description of:(1) the technological and technical aspects, and the expected performance of the instruments of the scientific payload;(2) the elements and functions of the mission, from the spacecraft to the ground segment.展开更多
The Medium Energy X-ray telescope(ME) is one of the three main telescopes on board the Insight hard X-ray modulation telescope(Insight-HXMT) astronomy satellite. ME contains 1728 pixels of Si-PIN detectors sensitive i...The Medium Energy X-ray telescope(ME) is one of the three main telescopes on board the Insight hard X-ray modulation telescope(Insight-HXMT) astronomy satellite. ME contains 1728 pixels of Si-PIN detectors sensitive in 5-30 ke V with a total geometrical area of 952 cm^2. The application specific integrated circuit(ASIC) chip, VA32TA6, is used to achieve low power consumption and low readout noise. The collimators define three kinds of field of views(FOVs) for the telescope, 1°×4°, 4°×4°,and blocked ones. Combination of such FOVs can be used to estimate the in-orbit X-ray and particle background components.The energy resolution of ME is ~3 ke V at 17.8 ke V(FWHM) and the time resolution is 255 μs. In this paper, we introduce the design and performance of ME.展开更多
1 Introduction Mobile cloud computing(MCC)can break the limitations of mobile devices by migrating applications to the Cloud with richer computing and storage resources[1].Consequently,mobile users can obtain better s...1 Introduction Mobile cloud computing(MCC)can break the limitations of mobile devices by migrating applications to the Cloud with richer computing and storage resources[1].Consequently,mobile users can obtain better service experience,improved processing power and reliability,expansion of storage capacity and so on[2].We focus on the computational offloading problem in the multi-cloudlet architecture(Fig.1).展开更多
文摘The COVID-19 is a major global health event that has changed people’s lives and behaviors. As a fragile and sensitive area with high population density and poor living conditions in the city, collective housing is also an important construction area for future urban renewal. In the process of the spread of the new crown epidemic, the collective housing has exposed a series of weaknesses such as difficult community management, inconvenience of life, and insufficient outdoor space. Therefore, the update and transformation of the outdoor environment of the collective housing combined with the concept of public health is a problem that must be considered at present. This article combines the practice of renewal and transformation of the X community in Chaoyang District, Beijing, combined with survey methods such as questionnaires, interviews, and observations, combined with the needs of residents and the practical experience of the grassroots management unit, and carried out an overall renewal design of the external space environment of the collective housing. The epidemic is combined with the division of functional layout, refined design of outdoor activity space to ensure safe distance, and increased shared smart facilities to improve the quality of the outdoor environment of collective residences and strengthen community resilience;to achieve communication and sharing, epidemic prevention and control on the basis of ensuring safe social distance outdoor sports and other functions. In this way, the ability of collective housing to prevent, identify, and dispose of urban risks will be improved, and will provide residents with a better and livable community life.
基金supported by the Strategic Priority Program on Space Science,the Chinese Academy of Sciences,Grant No.XDA15020500,XDA15020501,XDA15020501-02.
文摘Background The Gas Pixel Detector(GPD)is a key part of the Polarimetry Focusing Array(PFA)sub-system onboard the enhance X-ray Timing and Polarimetry mission(eXTP).The GPD can accurately provide the polarized angle and degree for incoming soft X-rays(requirements of minimum detectable polarization<1%(10^(6) s,1 mCrab))from celestial objects under extreme conditions of density,gravity and magnetism.Purpose Paste the GPD chips on a matched ceramic package is one of the most important procedures for the GPD assembly,and the parallelism between the top surface of an ASIC chip and the bottom surface of a Gas Electron Multiplier(GEM)foil can have impact on the distribution of electric field within transfer region and reconstruction of photoelectric trajectories,resulting in deterioration of the GPD sensitivity.This study quantifies the influence and gives a reasonable expectation of the parallelism.Methods A simulation framework of the GPD is constructed to quantify the influence on the GPD performance and values of the parallelism are measured by a gauge with a position resolution of o.1μm.Results:The difference of degree of modulation is less than 1% comparing the parallelism with a value of 20μm to a value of 0μm in response to both polarized and unpolarized X-rays.Meanwhile,the value of parallelism can reach 6.9±3.4μm(0.0176°±0.0087°)by testing and verifying.Conclusions The impact on the GPD performance can be less than 1%as the parallelism with an order of 20μm,and we also give a reasonable measuring method and verify the controllability and feasibility of the parallelism with an order of 20μm for pasting the ASIC chip on the surface of a ceramic package.
文摘Background Accurate preoperative evaluation of the levator palpebrae superioris(LPS)strength is required for specific calculation of anterior migration or shortening.This information serves as a surgical reference for more accurate correction of ptosis.Methods Between June 2017 and June 2019,155 eyes of 97 patients were studied.Patients were divided into the following 3 groups based on the ptosis degree:mild(28 cases),moderate(53 cases),and severe(16 cases).The LPS strength was evaluated preoperatively and used to calculate LPS anterior migration and shortening.The LPS aponeurosis and Müller’s muscle(L-M)complex was separated from the upper margin of the tarsal plate to the calculated height according to the levator muscle suspension system retention approach.The complex was subsequently fixed to the planned tarsal plate location.The upper eyelid margin(UEM)height,eyelid morphology,eyelid closure,eye symmetry,exposure keratitis status,and patient satisfaction were evaluated at 1 week and at 1 and 6 months postoperatively.Results In all cases,the UEM positions were normal,and only patients with severe ptosis exhibited lagophthalmos in the early posterative period.Six months postoperatively,13%of eyes in the severe group had residual ptosis;all mild and moderate cases exhibited good surgical outcomes.The eyelids closed well with no exposure keratitis.All patients were satisfied with the eyelid contour.Conclusions Accurate LPS anterior migration and aponeurosis shortening can eliminate various factors affecting surgical blepharoptosis treatment.These procedures not only reduce operation time but also enhance the stability of postoperative correction.
文摘Blepharoptosis is a symptom that is commonly observed in clinics.It presents with drooping of the upper eyelid and an asymmetric appearance of the eye.It can occur because of various causes.If left untreated,severe congenital blepharoptosis may impair visual function.The surgical approach largely depends on the severity of blepharoptosis,Bell’s phenomenon,and surgical history.However,it is intricate and difficult to achieve satisfactory symmetry and avoid complications.Owing to the complexity involved and discrepancies in treatment,we planned to arrive at a consensus on the diagnosis and correction of blepharoptosis among Chinese plastic surgeons and ophthalmologists,aiming to establish more standardized treatments and cause less harm to patients.
基金This work was supported by the Health Commission of Hubei Province Scientific Research Project(No.WJ2021M129)the National Key Research and Development Program of China(No.2021YFC2701502)。
文摘Melatonin receptor 1B(MT2,encoded by the MTNR1B gene),a high-affinity receptor for melatonin,is associated with glucose homeostasis including glucose uptake and transport.The rs10830963 variant in the MTNR1B gene is linked to glucose metabolism disorders including gestational diabetes mellitus(GDM);however,the relationship between MT2-mediated melatonin signaling and a high birth weight of GDM infants from maternal glucose abnormality remains poorly understood.This article aims to investigate the relationship between rs10830963 variants and GDM development,as well as the effects of MT2 receptor on glucose uptake and transport in trophoblasts.TaqMan-MGB(minor groove binder)probe quantitative realtime polymerase chain reaction(qPCR)assays were used for rs10930963 genotyping.MT2 expression in the placenta of GDM and normal pregnant women was detected by immunofluorescence,western blot,and qPCR.The relationship between MT2 and glucose transporters(GLUTs)or peroxisome proliferator-activated receptorγ(PPARγ)was established by western blot,and glucose consumption of trophoblasts was measured by a glucose assay kit.The results showed that the genotype and allele frequencies of rs10830963 were significantly different between GDM and normal pregnant women(P<0.05).The fasting,1-h and 2-h plasma glucose levels of G-allele carriers were significantly higher than those of C-allele carriers(P<0.05).Besides,the protein and messenger RNA(mRNA)expression of MT2 in the placenta of GDM was significantly higher than that of normal pregnant women(P<0.05).Melatonin could stimulate glucose uptake and GLUT4 and PPARγprotein expression in trophoblasts,which could be attenuated by MT2 receptor knockdown.In conclusion,the rs10830963 variant was associated with an increased risk of GDM.The MT2 receptor is essential for melatonin to raise glucose uptake and transport,which may be mediated by PPARγ.
基金support from the National Program on Key Research and Development Project(Grant No.2021YFA0718500)from the Ministry of Science and Technology of China(MOST)The authors thank supports from the National Natural Science Foundation of China under Grants 12273043,U1838201,U1838202,U1938109,U1938102,U1938108,and U2038109This work was partially supported by the International Partnership Program of the Chinese Academy of Sciences(Grant No.113111KYSB20190020).
文摘Introduction The medium-energy X-ray telescope(ME)is a collimated X-ray telescope onboard the Insight hard X-ray modulation telescope(Insight-HXMT)satellite.It has 1728 Si-PIN pixels readout using 54 low noise application-specific integrated circuits(ASICs).ME covers the energy range of 5–30 keV and has a total detection area of 952cm2.The typical energy resolution of ME at the beginning of the mission is 3 keV at 17.8 keV(full width at half maximum,FWHM),and the time resolution is 255μs.In this study,we present the in-orbit performance of ME in its first 5 years of operation.Methods The performance of ME was monitored using onboard radioactive sources and astronomical X-ray objects.ME carries six 241Am radioactive sources for onboard calibration,which can continuously illuminate the calibration pixels.The long-term performance evolution of ME can be quantified using the properties of the accumulated spectra of the calibration pixels.In addition,observations of the Crab Nebula and the pulsar were used to check the long-term evolution of the detection efficiency as a function of energy.Conclusion After 5 years of operation,742cm2 of the Si-PIN pixelswere stillworking normally.The peak positions of 241Am emission lines gradually shifted to the high-energy region,implying a slow increase in ME gain of 1.43%.A comparison of the ME spectra of the Crab Nebula and the pulsar shows that the E–C relations and the redistribution matrix file are still acceptable for most data analysis works,and there is no detectable variation in the detection efficiency.
基金supported by the National Program on Key Research and Development Project(Grant No.2016YFA0400800)from the Ministry of Science and Technology of China(MOST)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB23040400)the Hundred Talent Program of Chinese Academy of Sciences,the National Natural Science Foundation of China(Grant Nos.11233001,11503027,11403026,11473027,and11733009)
文摘Finding the electromagnetic(EM) counterpart of binary compact star merger, especially the binary neutron star(BNS) merger,is critically important for gravitational wave(GW) astronomy, cosmology and fundamental physics. On Aug. 17, 2017,Advanced LIGO and Fermi/GBM independently triggered the first BNS merger, GW170817, and its high energy EM counterpart,GRB 170817 A, respectively, resulting in a global observation campaign covering gamma-ray, X-ray, UV, optical, IR, radio as well as neutrinos. The High Energy X-ray telescope(HE) onboard Insight-HXMT(Hard X-ray Modulation Telescope) is the unique high-energy gamma-ray telescope that monitored the entire GW localization area and especially the optical counterpart(SSS17 a/AT2017 gfo) with very large collection area(~1000 cm^2) and microsecond time resolution in 0.2-5 MeV. In addition,Insight-HXMT quickly implemented a Target of Opportunity(ToO) observation to scan the GW localization area for potential X-ray emission from the GW source. Although Insight-HXMT did not detect any significant high energy(0.2-5 MeV) radiation from GW170817, its observation helped to confirm the unexpected weak and soft nature of GRB 170817 A. Meanwhile,Insight-HXMT/HE provides one of the most stringent constraints(~10^(-7) to 10^(-6) erg/cm^2/s) for both GRB170817 A and any other possible precursor or extended emissions in 0.2-5 MeV, which help us to better understand the properties of EM radiation from this BNS merger. Therefore the observation of Insight-HXMT constitutes an important chapter in the full context of multi-wavelength and multi-messenger observation of this historical GW event.
基金support of the Chinese Academy of Sciences through the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA15020100)support by ASI, under the dedicated eXTP agreements and agreement ASI-INAF (Grant No. 2017-14-H.O.)+3 种基金by INAF and INFN under project REDSOXsupport from the Deutsche Zentrum für Luft- und Raumfahrt, the German Aerospce Center (DLR)support of Science Centre (Grant No. 2013/10/M/ST9/00729)support from MINECO (Grant No. ESP2017-82674-R) and FEDER funds
文摘In this paper we present the enhanced X-ray Timing and Polarimetry mission—eXTP. eXTP is a space science mission designed to study fundamental physics under extreme conditions of density, gravity and magnetism. The mission aims at determining the equation of state of matter at supra-nuclear density, measuring effects of QED, and understanding the dynamics of matter in strong-field gravity. In addition to investigating fundamental physics, eXTP will be a very powerful observatory for astrophysics that will provide observations of unprecedented quality on a variety of galactic and extragalactic objects. In particular, its wide field monitoring capabilities will be highly instrumental to detect the electro-magnetic counterparts of gravitational wave sources.The paper provides a detailed description of:(1) the technological and technical aspects, and the expected performance of the instruments of the scientific payload;(2) the elements and functions of the mission, from the spacecraft to the ground segment.
基金the Strategic Priority Research Program on Space Science,the Chinese Academy of Sciences(Grant No.XDA040102).
文摘The Medium Energy X-ray telescope(ME) is one of the three main telescopes on board the Insight hard X-ray modulation telescope(Insight-HXMT) astronomy satellite. ME contains 1728 pixels of Si-PIN detectors sensitive in 5-30 ke V with a total geometrical area of 952 cm^2. The application specific integrated circuit(ASIC) chip, VA32TA6, is used to achieve low power consumption and low readout noise. The collimators define three kinds of field of views(FOVs) for the telescope, 1°×4°, 4°×4°,and blocked ones. Combination of such FOVs can be used to estimate the in-orbit X-ray and particle background components.The energy resolution of ME is ~3 ke V at 17.8 ke V(FWHM) and the time resolution is 255 μs. In this paper, we introduce the design and performance of ME.
基金the National Natural Science Foundation of China(Grant Nos.61772068,61370132 and 61472033).
文摘1 Introduction Mobile cloud computing(MCC)can break the limitations of mobile devices by migrating applications to the Cloud with richer computing and storage resources[1].Consequently,mobile users can obtain better service experience,improved processing power and reliability,expansion of storage capacity and so on[2].We focus on the computational offloading problem in the multi-cloudlet architecture(Fig.1).
