Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor(GECAM),consisting of two microsatellites,is designed to detect gamma-ray bursts associated with gravitational-wave events.Here,we introduce th...Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor(GECAM),consisting of two microsatellites,is designed to detect gamma-ray bursts associated with gravitational-wave events.Here,we introduce the real-time burst alert system of GECAM,with the adoption of the BeiDou-3 short message communication service.We present the post-trigger operations,the detailed ground-based analysis,and the performance of the system.In the first year of the in-flight operation,GECAM was triggered by 42 gamma-ray bursts.The GECAM real-time burst alert system has the ability to distribute the alert within~1 minute after being triggered,which enables timely follow-up observations.展开更多
Fast and reliable localization of high-energy transients is crucial for characterizing the burst properties and guiding the follow-up observations.Localization based on the relative counts of different detectors has b...Fast and reliable localization of high-energy transients is crucial for characterizing the burst properties and guiding the follow-up observations.Localization based on the relative counts of different detectors has been widely used for all-sky gamma-ray monitors.There are two major methods for this count distribution localization:χ^(2)minimization method and the Bayesian method.Here we propose a modified Bayesian method that could take advantage of both the accuracy of the Bayesian method and the simplicity of the χ^(2)method.With comprehensive simulations,we find that our Bayesian method with Poisson likelihood is generally more applicable for various bursts than the χ^(2)method,especially for weak bursts.We further proposed a location-spectrum iteration approach based on the Bayesian inference,which could alleviate the problems caused by the spectral difference between the burst and location templates.Our method is very suitable for scenarios with limited computation resources or timesensitive applications,such as in-flight localization software,and low-latency localization for rapidly follow-up observations.展开更多
The Gravitational wave burst high-energy Electromagnetic Counterpart All-sky Monitor(GECAM)is a dedicated mission for monitoring high-energy transients.Here we report the design of the GECAM Scientific Ground Segment(...The Gravitational wave burst high-energy Electromagnetic Counterpart All-sky Monitor(GECAM)is a dedicated mission for monitoring high-energy transients.Here we report the design of the GECAM Scientific Ground Segment(GSGS)in terms of the scientific requirements,including the architecture,the external interfaces,the main function,and workflow.Judging from the analysis and verification results during the commissioning phase,the GSGS functions well and is able to monitor the status of the payloads,adjust the parameters,develop the scientific observation plans,generate the scientific data products,analyze the data,etc.Thus,the on-orbit operation and scientific researches of GECAM are guaranteed.展开更多
The interaction between dehydroeburicoic acid (DeEA), a triterpene purified from medicinal fungi and the major transport protein, human serum albumin (HSA), were systematically studied by fluorescence spectroscopy, sy...The interaction between dehydroeburicoic acid (DeEA), a triterpene purified from medicinal fungi and the major transport protein, human serum albumin (HSA), were systematically studied by fluorescence spectroscopy, synchronous fluorescence spectroscopy, three-dimensional fluorescence spectroscopy and molecular docking approach under simulated physiological conditions. The intrinsic fluorescence of HSA was quenched through the combination of static and dynamic quenching mechanism. DeEA cannot be stored and carried by HSA in the body at higher temperature. The hydrogen bonding, hydrophobic force and van der Waals force were major acting forces. The site II was the major binding site. The energy transfer could occur with high probability and the binding distance was 3.29 nm. The binding process slightly changed the conformation and microenvironment of HSA. The DeEA molecule entered the hydrophobic cleft of HSA and formed the hydrogen bonding with Glu-492 and Lys-545.展开更多
With the development of internationalization,English has gradually become the medium of international communication.As English is learned and used as a second language by people from different countries,nationalities ...With the development of internationalization,English has gradually become the medium of international communication.As English is learned and used as a second language by people from different countries,nationalities and cultures,English teachers pay more and more attention to the communication and interaction of language users around the world,and World English paradigm is noticed in the classroom.This paper introduces the attitudes of different countries towards the learning and use of different English variants in the Three Circle Model,and briefly describes the formation and development of Chinglish in China,and discusses the influence of the application of World English paradigm in English teaching from both positive and negative aspects.The use of World English paradigm in English classroom is conducive to learners'development of their communicative competence and cultural identity.However,using World English paradigm will also affect teachers'ability to distinguish English variants and errors in the sense of SLA.In English classroom,teachers should choose teaching materials from the perspective of multiculturalism and receive corresponding training to avoid the risk of using World English paradigm and effectively improve students'English communication level.展开更多
The growing interest in valorizing industrial by-products has led researchers to focus on exploring different sources and optimizing collagen extraction conditions over the past decade.While bovine hide,cattle bones,p...The growing interest in valorizing industrial by-products has led researchers to focus on exploring different sources and optimizing collagen extraction conditions over the past decade.While bovine hide,cattle bones,pork,and pig skins remain the most abundant collagen sources,there is a growing trend in the industrial utilization of collagen from non-mammalian species.This review explores alternative marine collagen sourcesand summarizes emerging trends in collagen recovery from marine sources,with a particular focus on environmentally friendly methods.Additionally,this review covers the colloidal structure-forming properties of marine collagens,including foam,film,gel,and emulsion formation.It also highlights the potential and important applications of marine collagen in various food products.Based on the currently reported marine sources,collagens extracted from fish,jellyfish,and sea cucumbers were found to have the highest yield and mostly comprised type-l collagen,while crustaceans and mollusks yielded lower percentages of collagen.Traditional extraction techniques isolate collagen based on acetic acid and pepsin treatment,but they come with drawbacks such as being time-consuming,causing sample destruction,and using solvents.Conversely,marine collagen extracted using conventional methods assisted with ultrasonication resulted in higher yields and strengthened the triple-stranded helical structures.Recently,an increasing number of new applications have been found in the food industry for marine collagens,such as biodegradable film-forming materials,colloid stabilizers,foaming agents,and micro-encapsulating agents.Furthermore,collagen is a modern foodstuff and is extensively used in the beverage,dairy,and meat industries to increase the stability,consistency,and elasticity of products.展开更多
We analyze China Securities Index Co.,Ltd.(CSI)environmental,social and governance(ESG)scoring data,which incorporate Chinese characteristics,to assess the impact of ESG performance on corporate debt financing costs.O...We analyze China Securities Index Co.,Ltd.(CSI)environmental,social and governance(ESG)scoring data,which incorporate Chinese characteristics,to assess the impact of ESG performance on corporate debt financing costs.Our findings indicate that better CSI ESG scores are correlated with lower debt financing costs.Additionally,improvements in local environmental execution enhance the effect of CSI ESG scores on debt financing costs.However,this effect diminishes with increased internal control quality and marketization.Governance has the greatest impact on reducing debt financing costs,followed by social and environmental factors.Superior CSI ESG scores reduce corporate debt financing costs by enhancing debt repayment capacity and reducing information asymmetry.Economic consequence analysis confirms that lower financing costs,driven by improved ESG performance,significantly enhance total factor productivity and firm value.CSI ESG scores also significantly impact bank loans but not corporate bond financing.展开更多
As China’s first X-ray astronomical satellite, the Hard X-ray Modulation Telescope (HXMT), which was dubbed as Insight-HXMT after the launch on June 15, 2017, is a wide-band(1-250 ke V) slat-collimator-based X-ray as...As China’s first X-ray astronomical satellite, the Hard X-ray Modulation Telescope (HXMT), which was dubbed as Insight-HXMT after the launch on June 15, 2017, is a wide-band(1-250 ke V) slat-collimator-based X-ray astronomy satellite with the capability of all-sky monitoring in 0.2-3 Me V. It was designed to perform pointing, scanning and gamma-ray burst(GRB)observations and, based on the Direct Demodulation Method (DDM), the image of the scanned sky region can be reconstructed.Here we give an overview of the mission and its progresses, including payload, core sciences, ground calibration/facility, ground segment, data archive, software, in-orbit performance, calibration, background model, observations and some preliminary results.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
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 fundament...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 170817A, 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 （SSS17a/AT2017gfo） with very large collection area （M000 cm2） 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 170817A. Meanwhile, Insight-HXMT/HE provides one of the most stringent constraints （-10-7 to 104 erg/cm2/s） for both GRB170817A 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
Firstly, a multi-field coupling finite element formulation of composited beam laminated with the photostrictive actuators is developed in this paper. Moreover, an optimal fuzzy active control algorithm is also propose...Firstly, a multi-field coupling finite element formulation of composited beam laminated with the photostrictive actuators is developed in this paper. Moreover, an optimal fuzzy active control algorithm is also proposed on the basis of the combination of optimal control and fuzzy one.This method opens a new avenue to resolve the contradiction between the linear system control method and nonlinear actuating characteristics of photostrictive actuators. The desired control for suppressing multi-modal vibration of photoelectric laminated beam is firstly obtained through optimal control and then the fuzzy control is used to approach the desired mechanical strain induced by photostrictive actuators. Thus, the multi-mode vibration control of beam is realized.In the design process of optimal fuzzy controller, the design of fuzzy control is independent of optimal control. The simulation results demonstrate that the proposed control method can effectively realize multi-modal vibration control of photoelectric laminated beams, and the control effect of optimal fuzzy control is better than that of optimal state feedback control.展开更多
This article provides a review on X-ray pulsar-based navigation(XNAV).The review starts with the basic concept of XNAV,and briefly introduces the past,present and future projects concerning XNAV.This paper focuses on ...This article provides a review on X-ray pulsar-based navigation(XNAV).The review starts with the basic concept of XNAV,and briefly introduces the past,present and future projects concerning XNAV.This paper focuses on the advances of the key techniques supporting XNAV,including the navigation pulsar database,the X-ray detection system,and the pulse time of arrival estimation.Moreover,the methods to improve the estimation performance of XNAV are reviewed.Finally,some remarks on the future development of XNAV are provided.展开更多
In this White Paper we present the potential of the Enhanced X-ray Timing and Polarimetry(eXTP) mission for determining the nature of dense matter; neutron star cores host an extreme density regime which cannot be rep...In this White Paper we present the potential of the Enhanced X-ray Timing and Polarimetry(eXTP) mission for determining the nature of dense matter; neutron star cores host an extreme density regime which cannot be replicated in a terrestrial laboratory. The tightest statistical constraints on the dense matter equation of state will come from pulse profile modelling of accretion-powered pulsars, burst oscillation sources, and rotation-powered pulsars. Additional constraints will derive from spin measurements, burst spectra, and properties of the accretion flows in the vicinity of the neutron star. Under development by an international Consortium led by the Institute of High Energy Physics of the Chinese Academy of Sciences, the eXTP mission is expected to be launched in the mid 2020 s.展开更多
Background The Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor(GECAM)is primarily designed to spot gamma-ray bursts corresponding to gravitational waves.In order to achieve stable observatio...Background The Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor(GECAM)is primarily designed to spot gamma-ray bursts corresponding to gravitational waves.In order to achieve stable observations from various astronomical phenomena,the payload performance need to be monitored during the in-orbit operation.Method This article describes the design and implementation of GECAM satellite payload performance monitoring(GPPM)software.The software extracts the payload status and telescope observations(light curves,energy spectrums,characteristic peak fitting of energy spectrums,etc)from the payload data.Considering the large amount of payload status parameters in the engineering data,we have designed a method of parameter processing based on the configuration tables.This method can deal with the frequent changes of the data formats and facilitate program maintenance.Payload status and performance are monitored through defined thresholds and monitoring reports.The entire software is implemented in python language and the huge amount of observation data is stored in MongoDB.Conclusion The design and implementation of GPPM software have been completed,tested with ground and in-orbit payload data.The software can monitor the performance of GECAM payload effectively.The overall design of the software and the data processing method can be applied to other satellites.展开更多
基金supported by the National Key R&D Program of China(2021YFA0718500,2022YFF0711404)the Strategic Priority Research Program on Space Science,the Chinese Academy of Sciences(grant Nos.XDA15360300,XDA15052700 and E02212A02S)+1 种基金the National Natural Science Foundation of China(grant Nos.U2031205,12133007)supported by the Strategic Priority Research Program on Space Science,the Chinese Academy of Sciences,grant No.XDA15360000。
文摘Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor(GECAM),consisting of two microsatellites,is designed to detect gamma-ray bursts associated with gravitational-wave events.Here,we introduce the real-time burst alert system of GECAM,with the adoption of the BeiDou-3 short message communication service.We present the post-trigger operations,the detailed ground-based analysis,and the performance of the system.In the first year of the in-flight operation,GECAM was triggered by 42 gamma-ray bursts.The GECAM real-time burst alert system has the ability to distribute the alert within~1 minute after being triggered,which enables timely follow-up observations.
基金supported by the National Key R&D Program of China(2021YFA0718500)support from the Strategic Priority Research Program on Space Science,the Chinese Academy of Sciences(grant Nos.XDA15360102,XDA15360300,XDA15052700 and E02212A02S)+1 种基金the National Natural Science Foundation of China(grant Nos.12173038 and U2038106)the National HEP Data Center(grant No.E029S2S1)。
文摘Fast and reliable localization of high-energy transients is crucial for characterizing the burst properties and guiding the follow-up observations.Localization based on the relative counts of different detectors has been widely used for all-sky gamma-ray monitors.There are two major methods for this count distribution localization:χ^(2)minimization method and the Bayesian method.Here we propose a modified Bayesian method that could take advantage of both the accuracy of the Bayesian method and the simplicity of the χ^(2)method.With comprehensive simulations,we find that our Bayesian method with Poisson likelihood is generally more applicable for various bursts than the χ^(2)method,especially for weak bursts.We further proposed a location-spectrum iteration approach based on the Bayesian inference,which could alleviate the problems caused by the spectral difference between the burst and location templates.Our method is very suitable for scenarios with limited computation resources or timesensitive applications,such as in-flight localization software,and low-latency localization for rapidly follow-up observations.
基金supported by the National Key R&D Program of China(2022YFF0711404,2021YFA0718500)International Partnership Program of Chinese Academy of Sciences(grant No.113111KYSB20190020)+2 种基金the National Natural Science Foundation of China(NSFC,Grant No.U1938106)the open subject of the National HEP Data Center(E029S2S1)support from the Strategic Priority Research Program on Space Science,the Chinese Academy of Sciences(grant Nos.XDA15360102,XDA15360300,XDA15052700 and E02212A02S)。
文摘The Gravitational wave burst high-energy Electromagnetic Counterpart All-sky Monitor(GECAM)is a dedicated mission for monitoring high-energy transients.Here we report the design of the GECAM Scientific Ground Segment(GSGS)in terms of the scientific requirements,including the architecture,the external interfaces,the main function,and workflow.Judging from the analysis and verification results during the commissioning phase,the GSGS functions well and is able to monitor the status of the payloads,adjust the parameters,develop the scientific observation plans,generate the scientific data products,analyze the data,etc.Thus,the on-orbit operation and scientific researches of GECAM are guaranteed.
文摘The interaction between dehydroeburicoic acid (DeEA), a triterpene purified from medicinal fungi and the major transport protein, human serum albumin (HSA), were systematically studied by fluorescence spectroscopy, synchronous fluorescence spectroscopy, three-dimensional fluorescence spectroscopy and molecular docking approach under simulated physiological conditions. The intrinsic fluorescence of HSA was quenched through the combination of static and dynamic quenching mechanism. DeEA cannot be stored and carried by HSA in the body at higher temperature. The hydrogen bonding, hydrophobic force and van der Waals force were major acting forces. The site II was the major binding site. The energy transfer could occur with high probability and the binding distance was 3.29 nm. The binding process slightly changed the conformation and microenvironment of HSA. The DeEA molecule entered the hydrophobic cleft of HSA and formed the hydrogen bonding with Glu-492 and Lys-545.
文摘With the development of internationalization,English has gradually become the medium of international communication.As English is learned and used as a second language by people from different countries,nationalities and cultures,English teachers pay more and more attention to the communication and interaction of language users around the world,and World English paradigm is noticed in the classroom.This paper introduces the attitudes of different countries towards the learning and use of different English variants in the Three Circle Model,and briefly describes the formation and development of Chinglish in China,and discusses the influence of the application of World English paradigm in English teaching from both positive and negative aspects.The use of World English paradigm in English classroom is conducive to learners'development of their communicative competence and cultural identity.However,using World English paradigm will also affect teachers'ability to distinguish English variants and errors in the sense of SLA.In English classroom,teachers should choose teaching materials from the perspective of multiculturalism and receive corresponding training to avoid the risk of using World English paradigm and effectively improve students'English communication level.
基金funded by the"Pioneer"and"Leading Goose"R&D Program of Zhejiang Province(2023C02044).
文摘The growing interest in valorizing industrial by-products has led researchers to focus on exploring different sources and optimizing collagen extraction conditions over the past decade.While bovine hide,cattle bones,pork,and pig skins remain the most abundant collagen sources,there is a growing trend in the industrial utilization of collagen from non-mammalian species.This review explores alternative marine collagen sourcesand summarizes emerging trends in collagen recovery from marine sources,with a particular focus on environmentally friendly methods.Additionally,this review covers the colloidal structure-forming properties of marine collagens,including foam,film,gel,and emulsion formation.It also highlights the potential and important applications of marine collagen in various food products.Based on the currently reported marine sources,collagens extracted from fish,jellyfish,and sea cucumbers were found to have the highest yield and mostly comprised type-l collagen,while crustaceans and mollusks yielded lower percentages of collagen.Traditional extraction techniques isolate collagen based on acetic acid and pepsin treatment,but they come with drawbacks such as being time-consuming,causing sample destruction,and using solvents.Conversely,marine collagen extracted using conventional methods assisted with ultrasonication resulted in higher yields and strengthened the triple-stranded helical structures.Recently,an increasing number of new applications have been found in the food industry for marine collagens,such as biodegradable film-forming materials,colloid stabilizers,foaming agents,and micro-encapsulating agents.Furthermore,collagen is a modern foodstuff and is extensively used in the beverage,dairy,and meat industries to increase the stability,consistency,and elasticity of products.
基金funded by the National Natural Science Foundation of China(Grant No.72172029,71971046,72272028)the National Social Science Foundation of China(Grant No.21FJYB032)a Project from the Educational Department of Liaoning Province(Grant No.LJKR0462).Professional English language editing support provided by AsiaEdit(asiaedit.com).
文摘We analyze China Securities Index Co.,Ltd.(CSI)environmental,social and governance(ESG)scoring data,which incorporate Chinese characteristics,to assess the impact of ESG performance on corporate debt financing costs.Our findings indicate that better CSI ESG scores are correlated with lower debt financing costs.Additionally,improvements in local environmental execution enhance the effect of CSI ESG scores on debt financing costs.However,this effect diminishes with increased internal control quality and marketization.Governance has the greatest impact on reducing debt financing costs,followed by social and environmental factors.Superior CSI ESG scores reduce corporate debt financing costs by enhancing debt repayment capacity and reducing information asymmetry.Economic consequence analysis confirms that lower financing costs,driven by improved ESG performance,significantly enhance total factor productivity and firm value.CSI ESG scores also significantly impact bank loans but not corporate bond financing.
基金project funded by China National Space Administration(CNSA)and the Chinese Academy of Sciences(CAS)support from the National Key Research and Development Program of China(Grant No.2016YFA0400800)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDA04010202,XDA04010300,and XDB23040400)the National Natural Science Foundation of China(Grant Nos.U1838201,and U1838102).
文摘As China’s first X-ray astronomical satellite, the Hard X-ray Modulation Telescope (HXMT), which was dubbed as Insight-HXMT after the launch on June 15, 2017, is a wide-band(1-250 ke V) slat-collimator-based X-ray astronomy satellite with the capability of all-sky monitoring in 0.2-3 Me V. It was designed to perform pointing, scanning and gamma-ray burst(GRB)observations and, based on the Direct Demodulation Method (DDM), the image of the scanned sky region can be reconstructed.Here we give an overview of the mission and its progresses, including payload, core sciences, ground calibration/facility, ground segment, data archive, software, in-orbit performance, calibration, background model, observations and some preliminary results.
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 170817A, 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 （SSS17a/AT2017gfo） with very large collection area （M000 cm2） 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 170817A. Meanwhile, Insight-HXMT/HE provides one of the most stringent constraints （-10-7 to 104 erg/cm2/s） for both GRB170817A 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supported by the National Natural Science Foundation of China, China (No. 11572151)
文摘Firstly, a multi-field coupling finite element formulation of composited beam laminated with the photostrictive actuators is developed in this paper. Moreover, an optimal fuzzy active control algorithm is also proposed on the basis of the combination of optimal control and fuzzy one.This method opens a new avenue to resolve the contradiction between the linear system control method and nonlinear actuating characteristics of photostrictive actuators. The desired control for suppressing multi-modal vibration of photoelectric laminated beam is firstly obtained through optimal control and then the fuzzy control is used to approach the desired mechanical strain induced by photostrictive actuators. Thus, the multi-mode vibration control of beam is realized.In the design process of optimal fuzzy controller, the design of fuzzy control is independent of optimal control. The simulation results demonstrate that the proposed control method can effectively realize multi-modal vibration control of photoelectric laminated beams, and the control effect of optimal fuzzy control is better than that of optimal state feedback control.
基金the National Natural Science Foundation of China(No.61703413)the Science and Technology Innovation Program of Hunan Province,China(No.2021RC3078).
文摘This article provides a review on X-ray pulsar-based navigation(XNAV).The review starts with the basic concept of XNAV,and briefly introduces the past,present and future projects concerning XNAV.This paper focuses on the advances of the key techniques supporting XNAV,including the navigation pulsar database,the X-ray detection system,and the pulse time of arrival estimation.Moreover,the methods to improve the estimation performance of XNAV are reviewed.Finally,some remarks on the future development of XNAV are provided.
基金support from ERC Starting (Grant No. 639217 CSINEUTRONSTAR)support from a Netherlands Organization for Scientific Research (NWO) Vidi Fellowship+2 种基金suported by the European Union Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie Global Fellowship (Grant No. 703916)supported in part by the DFG through Grant SFB 1245 and the ERC (Grant No. 307986 STRONGINT)support of the Chinese Academy of Sciences through the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA15020100)
文摘In this White Paper we present the potential of the Enhanced X-ray Timing and Polarimetry(eXTP) mission for determining the nature of dense matter; neutron star cores host an extreme density regime which cannot be replicated in a terrestrial laboratory. The tightest statistical constraints on the dense matter equation of state will come from pulse profile modelling of accretion-powered pulsars, burst oscillation sources, and rotation-powered pulsars. Additional constraints will derive from spin measurements, burst spectra, and properties of the accretion flows in the vicinity of the neutron star. Under development by an international Consortium led by the Institute of High Energy Physics of the Chinese Academy of Sciences, the eXTP mission is expected to be launched in the mid 2020 s.
基金This work is supported by the Strategic Prior-ity Research Program of Chinese Academy of Sciences(Grant Nos.XDA15360300,XDA15360302 and XDB23040400).
文摘Background The Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor(GECAM)is primarily designed to spot gamma-ray bursts corresponding to gravitational waves.In order to achieve stable observations from various astronomical phenomena,the payload performance need to be monitored during the in-orbit operation.Method This article describes the design and implementation of GECAM satellite payload performance monitoring(GPPM)software.The software extracts the payload status and telescope observations(light curves,energy spectrums,characteristic peak fitting of energy spectrums,etc)from the payload data.Considering the large amount of payload status parameters in the engineering data,we have designed a method of parameter processing based on the configuration tables.This method can deal with the frequent changes of the data formats and facilitate program maintenance.Payload status and performance are monitored through defined thresholds and monitoring reports.The entire software is implemented in python language and the huge amount of observation data is stored in MongoDB.Conclusion The design and implementation of GPPM software have been completed,tested with ground and in-orbit payload data.The software can monitor the performance of GECAM payload effectively.The overall design of the software and the data processing method can be applied to other satellites.
