The in-flight instrumental background of the Follow-up X-ray Telescope(FXT)onboard Einstein Probe mis sion is analysed in this work by utilizing observations collected during the performance verification phase and sub...The in-flight instrumental background of the Follow-up X-ray Telescope(FXT)onboard Einstein Probe mis sion is analysed in this work by utilizing observations collected during the performance verification phase and subsequent dedicated filter wheel closed observations.The instrumental backgrounds of the two FXT modules are consistent with each other,with an average rate of~4×10^(-2)counts s^(-1)keV^(-1)in the 0.5-10 keV band for each module.The background is nearly uniformly distributed across the detector area,with a minor increase(<8%)observed along rows.The spatial distribution shows significant modulation by the geomagnetic field.The spectral shapes remain unchanged in 0.5-10 keV at different rates.The long-term temporal variation indicates a periodic change associated with the orbital precession(~57 days).The innovative design of FXT full-frame readout mode enables simultaneous recording of events in both the imaging area(IMG)and the frame store area(FSA)of the pnCCD.FSA event rates show a strong linear correlation with the IMG,based on which the IMG instrumental background modeling is established.展开更多
The Follow-up X-ray Telescope(FXT)is one of the main scientific instruments on board the Einstein Probe astronomical satellite,which was launched in 2024 January.FXT consists of two Wolter I type nested telescopes(FXT...The Follow-up X-ray Telescope(FXT)is one of the main scientific instruments on board the Einstein Probe astronomical satellite,which was launched in 2024 January.FXT consists of two Wolter I type nested telescopes(FXT-A and FXT-B)with a focal length of 1600 mm.The focal plane detector employs a PNCCD with 384×384 pixels.The timing mode of FXT serves as the primary operating mode for fast X-ray timing observations.To evaluate and validate the timing performance of FXT prior to launch,a comprehensive timing calibration was performed at the 100 m X-ray test facility.By simulating various periodic Crab-like profiles using the Grid Controlled X-ray Tube(GCXT)in conjunction with a pulsar simulation module,it was verified that the relative time accuracy of FXT exceeds 5×10^(−9).Furthermore,employing GCXT with a voltage pulse generation module enabled the determination of the time resolutions for FXT-A and FXT-B,recorded as 45.6±2.7μs and 47.1±2.8μs,respectively.An absolute timing calibration for FXT-B was carried out using the GCXT and a time interval analyzer,revealing a measured time delay of 3.9±2.1μs for FXT-B.展开更多
1.Introduction 2020 is an unusual year in which the COVID-19 pandemic has raged through the globe,infecting tens of millions of people and killing hundreds of thousands.The pandemic has not only wreaked havoc on publi...1.Introduction 2020 is an unusual year in which the COVID-19 pandemic has raged through the globe,infecting tens of millions of people and killing hundreds of thousands.The pandemic has not only wreaked havoc on public health systems,economic activities,and people's lives,but also has greatly affected and will continue to reshape the world's political,economic,and trade patterns.展开更多
Recombinant adenovirus serotype 5(Ad5)vector has been widely applied in vaccine development targeting infectious diseases,such as Ebola virus disease and coronavirus disease 2019(COVID-19).However,the high prevalence ...Recombinant adenovirus serotype 5(Ad5)vector has been widely applied in vaccine development targeting infectious diseases,such as Ebola virus disease and coronavirus disease 2019(COVID-19).However,the high prevalence of preexisting anti-vector immunity compromises the immunogenicity of Ad5-based vaccines.Thus,there is a substantial unmet need to minimize preexisting immunity while improving the insert-induced immunity of Ad5 vectors.Herein,we address this need by utilizing biocompatible nanoparticles to modulate Ad5–host interactions.We show that positively charged human serum albumin nanoparticles((+)HSAnp),which are capable of forming a complex with Ad5,significantly increase the transgene expression of Ad5 in both coxsackievirus–adenovirus receptor-positive and-negative cells.Furthermore,in charge-and dose-dependent manners,Ad5/(+)HSAnp complexes achieve robust(up to227-fold higher)and long-term(up to 60 days)transgene expression in the lungs of mice following intranasal instillation.Importantly,in the presence of preexisting anti-Ad5 immunity,complexed Ad5-based Ebola and COVID-19 vaccines significantly enhance antigen-specific humoral response and mucosal immunity.These findings suggest that viral aggregation and charge modification could be leveraged to engineer enhanced viral vectors for vaccines and gene therapies.展开更多
In this paper,we introduce the notion of a generalized weak group-like algebra which is designed to cover finite groupoid algebras and group-like algebras.Then we construct a list of examples and show that a generaliz...In this paper,we introduce the notion of a generalized weak group-like algebra which is designed to cover finite groupoid algebras and group-like algebras.Then we construct a list of examples and show that a generalized weak group-like algebra can be regarded as a generalized weak bi-Frobenius algebra.Moreover,we discuss when a generalized weak bi-Frobenius algebra is a groupoid algebra.Finally,we give the classifications of low-dimensional generalized weak group-like algebras.展开更多
Background:The Einstein Probe mission is an astronomical satellite developed in China,focusing on time-domain astronomy in the soft X-ray energy band.A key payload of this mission is the follow-up X-ray telescope(FXT)...Background:The Einstein Probe mission is an astronomical satellite developed in China,focusing on time-domain astronomy in the soft X-ray energy band.A key payload of this mission is the follow-up X-ray telescope(FXT),which is the result of international collaboration between China and Europe.The FXT features gold-coated nickel Wolter-I-type focusing mirrors and utilizes PNCCD detectors for imaging and spectroscopy in the focal plane.Methods:We reviewed the seven-year development history of the FXT.Initially,the configuration of the FXT consisted of a single telescope unit in 2017,but it later evolved into a dual-unit setup.Building on the successful design of eROSITA,the FXT team has innovatively introduced new operational modes for the PNCCD.FXT team also developed an ultra-compact helium pulse tube refrigerator,which cools the PNCCD down to-90℃.Additionally,various passive shielding measures have been implemented to protect against high-energy charged particles and enhance radiation resistance.These advancements have significantly improved the overall performance and reliability of the FXT.Results and conclusion:The ground calibrations and tests of the FXT demonstrate that its primary performance meets the established design goals.The FXT has exhibited outstanding performance in orbit,establishing itself as one of the space X-ray telescopes with considerable international influence.展开更多
Presently,the full implementation of the negotiations and collaborations under the Paris Agreement faces new key problems and severe challenges.These problems and challenges include the following:how to honor the prin...Presently,the full implementation of the negotiations and collaborations under the Paris Agreement faces new key problems and severe challenges.These problems and challenges include the following:how to honor the principle of“common but differentiated responsibilities”to facilitate a comprehensive,balanced,and effective implementation of the key elements of the Paris Agreement,such as adaptation,mitigation,finance,technology,capacity building,and transparency;how to uphold and maintain the status of China and other emerging countries as developing countries in light of the requirements of the United Nations Framework Convention on Climate Change and the historical responsibilities of these countries;and how to assess the goal of limiting the global temperature increase to 1.5℃and what constitutes an equitable carbon mitigation pathway for different types of countries.Developed countries and developing countries have drastically diverging views on carbon border adjustment measures for trade with developing countries proposed by several developed countries such as the European Union.Developed countries have demonstrated obvious intentions and actions designed to weaken and neglect the principle of“common but differentiated responsibilities”,to impose mitigation pressure on developing countries,to shift the responsibilities for emissions onto others,and to pass on the costs of mitigation.The maneuvering among different types of countries and interest groups has become increasingly intense.In response,China must maintain its strategic focus,adhere to the goals and principles established by the Paris Agreement,stick to its strategic positioning as a developing country,solidify strategic support from the developing world,and safeguard the legitimate rights and interests of developing countries.China played a conducive role in facilitating the Paris Agreement and has become an active participant,contributor,and leader in global climate governance.China must continue to follow Xi Jinping Thought on Socialism with Chinese Characteristics for a New Era and its conception of ecological civilization and the concept of building a community of common destiny,to actively lead the cooperation process in the construction of a global climate governance system characterized by equity,justice,and win-win collaborations,and to promote compliance with the Paris Agreement.At the same time,China should accelerate the green,low-carbon,circular transformation of its economy;accelerate the coordinated governance of the economy,environment,and climate change;and formulate and implement a long-term low-carbon development strategy.By the middle of the 21st century,while achieving the goal of building a great modern socialist country,China can also achieve a deep decarbonization development path that is in line with the goal of limiting the global temperature increase to well below 2°C and pursuing efforts to limit the increase to 1.5℃.展开更多
Purpose The follow-up X-ray telescope(FXT)is one of the two payloads of the Einstein Probe(EP),consisting of the upper composite with the X-ray mirror module as the core,the lower composite with the pnCCD module as th...Purpose The follow-up X-ray telescope(FXT)is one of the two payloads of the Einstein Probe(EP),consisting of the upper composite with the X-ray mirror module as the core,the lower composite with the pnCCD module as the core,and the interface structure.The FXT thermal control subsystem is responsible for the thermal design,thermal implementations,and testing of the entire FXT payload thermal control.Methods A design approach is adopted with passive thermal control technology as the main method and active thermal control technology as a supplement for common components.The X-ray mirror modules are high-precision optical components,utilizing active closed-loop temperature control to ensure high precision and stability.The pnCCD detectors operate at a stable low temperature,with refrigerators used to cool the detector houses,ensuring they can operate under stable low-temperature conditions.The hot ends of the refrigerators are connected to the external radiator panels through heat pipes for heat dissipation.Results The thermal control subsystem of FXT is operating properly in-orbit.All component temperatures meet the design requirements.Conclusion After multiple rounds of design and test verification,FXT was successfully launched with EP and completed in-orbit testing.During the in-orbit testing phase of EP,the function of the FXT thermal control subsystem works well.The temperatures of the components and units are normal.This paper introduces the design of FXT thermal control and the in-orbit performance of the thermal control subsystem.展开更多
Purpose The Einstein Probe(EP)satellite is a space X-ray satellite for time-domain astronomy and high-energy astrophysics.The precision control of the optical structure directly affects the imaging quality and positio...Purpose The Einstein Probe(EP)satellite is a space X-ray satellite for time-domain astronomy and high-energy astrophysics.The precision control of the optical structure directly affects the imaging quality and positioning accuracy of the Follow-up X-ray Telescope(FXT),playing a crucial role in achieving the on-orbit scientific objectives of the FXT.Higher positioning accuracy makes it easier to identify corresponding bodies for the discovery and positioning of transient sources.Accurate positioning is beneficial for follow-up observations in other bands,such as optical spectroscopy.Methods This article mainly introduces the precision control methods and processes of the FXT optical structure,which have been tested and verified through satellite test.The on-orbit source positioning accuracy of the FXT telescope is within 20 arcseconds(90% confidence level),meeting the requirements of the FXT mission.Results and Conclusion To ensure the accuracy of the EP satellite’s FXT optical structure,measures such as component processing control,installation control,and posttest adjustments are taken on the ground to ensure that the detector mounting position,optical axis deviation,and other precision indicators before and after the satellite lever test meet the design requirements.After a successful launch,through on-orbit calibration,the FXT-A and FXT-B optical axis pointing direction deviation is 39 arcseconds,and the source positioning error is better than 3'' at 68% confidence level.FXT optical structure meets all the requirements from design,processing,installation,etc.,successfully meeting scientific needs.展开更多
Purpose The Einstein Probe(EP)is an X-ray astronomical satellite designed for time-domain astronomy.The Follow-up X-ray Telescope(FXT)is an important payload on the EP.The FXT’s detector utilizes a pn-junction charge...Purpose The Einstein Probe(EP)is an X-ray astronomical satellite designed for time-domain astronomy.The Follow-up X-ray Telescope(FXT)is an important payload on the EP.The FXT’s detector utilizes a pn-junction charge-coupled device(pnCCD),which is currently the fastest-readout X-ray CCD worldwide.The design and implementation of a dedicated power-supply and monitoring module constitute a key aspect in the development of the detector system.Methods The FXT comprises several components,including the electric control box(EC-Box),the detector electronics box(DE-Box),and the focusing camera.The detector module of the focusing camera consists of two primary components:the pnCCD and the multi-channel analog signal processing chip known as the CAMEX(CMOS amplifier and multiplexer)ASIC.The CAMEX ASIC is used for the readout of the pnCCD signals.The operation of the detector module requires a sophisticated power-supply module.This paper details the design and implementation of a dedicated power-supply and monitoring module for the detector module.Based on the voltage requirements of the detector module,the power-supply module has been designed to include switchable,adjustable,and programmable functions.The monitoring module includes voltage,current,and temperature monitoring based on the different types of monitoring.Results The power-supply and monitoring module operates reliably and performs effectively in orbit,meeting the requirements of the FXT payload on the EP satellite.Conclusion The power-supply and monitoring module has successfully provided a stable power-supply and monitoring module for the detector module.It operates effectively in orbit,ensuring that the detector system achieves optimal performance.展开更多
In this paper,we present the current status of the enhanced X-ray Timing and Polarimetry mission,which has been fully approved for launch in 2030.eXTP is a space science mission designed to study fundamental physics u...In this paper,we present the current status of the enhanced X-ray Timing and Polarimetry mission,which has been fully approved for launch in 2030.eXTP is a space science mission designed to study fundamental physics under extreme conditions of matter density,gravity,and magnetism.The mission aims at determining the equation of state of matter at supra-nuclear density,measuring the effects of quantum electro-dynamics,and understanding the dynamics of matter in strong-field gravity.In addition to investigating fundamental physics,the eXTP mission is poised to become a leading observatory for time-domain and multi-messenger astronomy in the 2030s,as well as providing observations of unprecedented quality on a variety of galactic and extragalactic objects.After briefly introducing the history and a summary of the scientific objectives of the eXTP mission,this paper presents a comprehensive overview of:(1)the cutting-edge technology,technical specifications,and anticipated performance of the mission’s scientific instruments;(2)the full mission profile,encompassing spacecraft design,operational capabilities,and ground segment infrastructure.展开更多
Background The Einstein probe(EP)is an X-ray astronomical satellite dedicated to time-domain astronomy and high-energy astrophysics.Initiated at the end of 2017,it was successfully launched on January 9,2024.The follo...Background The Einstein probe(EP)is an X-ray astronomical satellite dedicated to time-domain astronomy and high-energy astrophysics.Initiated at the end of 2017,it was successfully launched on January 9,2024.The follow-up X-ray telescope(FXT)is a key payload on the EP satellite.The FXT employs PNCCD as its focal plane detector.Its electronic components include the electronic control box(EC-Box),the detector electronics boxes(DE-Box),the refrigerator controller,the movement mechanisms controller,and the temperature control instrument.Methods The FXT conducted functional performance tests in-orbit as planned,including three operating modes of the detector,energy detection range,and energy resolution.Results Since FXT became operational in orbit,all electronic equipment has been working stably.The FXT has an energy detection range of 0.3-10 keV,with an energy resolution of approximately 92 eV@1.25 keV,and an electronic noise of about 3.3e^(-).展开更多
Purpose:Mini-magnets of FXT are designed to deflect low-energy electrons that are incident into the camera aperture area,preventing them from reaching the focal plane detector and thereby reducing the noises they gene...Purpose:Mini-magnets of FXT are designed to deflect low-energy electrons that are incident into the camera aperture area,preventing them from reaching the focal plane detector and thereby reducing the noises they generate.Methods:By employing a combination of theoretical calculations and experimental measurements,the parameters of the FXT mini-magnets were obtained,including magnetic field distributions,magnetic moment results,and electron deflection efficiency.Results:The structural and magnetic models of the optimized mini-magnets are presented.Distributions of magnetic field intensity on different planes within the camera aperture are compared with the measured results from the FXT flight models(FMs).The results for the total and separated magnetic moment of two sets of FMs are also provided.Additionally,the deflection efficiency for 25 keV electrons is calculated under various incident conditions.Conclusion:The FMs of mini-magnets show good performance,with the measured values of magnetic field distributions being highly consistent with the theoretical values.A perfect result for total magnetic moment of less than 10mA·m^(2)has been achieved,far better than requirement of 100mA·m^(2).The calculated electron deflection efficiency reached over 99.88%,effectively fulfilling the objective of deflecting electrons in space.展开更多
We report the discovery of a peculiar X-ray transient,EP240408a,by Einstein Probe(EP)and follow-up studies made with EP,Swift,NICER,GROND,ATCA and other ground-based multiwavelength telescopes.The new transient was fi...We report the discovery of a peculiar X-ray transient,EP240408a,by Einstein Probe(EP)and follow-up studies made with EP,Swift,NICER,GROND,ATCA and other ground-based multiwavelength telescopes.The new transient was first detected with Wide-field X-ray Telescope(WXT)on board EP on April 8th,2024,manifested in an intense yet brief X-ray flare lasting for 12 s.The flare reached a peak flux of 3:9×10^(−9) erg cm^(−2) s^(−1) in 0.5-4 keV,∼300 times brighter than the underlying X-ray emission detected throughout the observation.Rapid and more precise follow-up observations by EP/FXT,Swift and NICER confirmed the finding of this new transient.Its X-ray spectrum is non-thermal in 0.5-10 keV,with a power-law photon index varying within 1.8-2.5.The X-ray light curve shows a plateau lasting for∼4 d,followed by a steep decay till becoming undetectable∼10 d after the initial detection.Based on its temporal property and constraints from previous EP observations,an unusual timescale in the range of 7-23 d is found for EP240408a,which is intermediate between the commonly found fast and long-term transients.No counterparts have been found in optical and near-infrared,with the earliest observation at 17 h after the initial X-ray detection,suggestive of intrinsically weak emission in these bands.We demonstrate that the remarkable properties of EP240408a are inconsistent with any of the transient types known so far,by comparison with,in particular,jetted tidal disruption events,gamma-ray bursts,X-ray binaries and fast blue optical transients.The nature of EP240408a thus remains an enigma.We suggest that EP240408a may represent a new type of transients with intermediate timescales of the order of∼10 d.The detection and follow-ups of more of such objects are essential for revealing their origin.展开更多
In order to induce the associative classical Yang-Baxter equations of any weight,we present the notion of an antisymmetric infinitesimal(ASI)bialgebra of weightλ,extending the ASI bialgebras to any weight.Meanwhile,w...In order to induce the associative classical Yang-Baxter equations of any weight,we present the notion of an antisymmetric infinitesimal(ASI)bialgebra of weightλ,extending the ASI bialgebras to any weight.Meanwhile,we consider the BiHomdeformation of the bialgebra above,which leads to the major research object that we need:nonhomogeneous associative BiHom-classical Yang-Baxter equations(abhcYBes).Subsequently,we focus on the characterizations and constructions of abhcYBes from generalized O-operators and weighted Rota-Baxter operators,which can be seen as a generalization of the main results in[Adv.Theor.Math.Phys.26(2022)19652009].展开更多
Purpose Design and implement a system within the detector electronic box of the FXT payload on the EP satellite to read out and acquire data from the pnCCD module of the focal plane detector.Methods The pnCCD module i...Purpose Design and implement a system within the detector electronic box of the FXT payload on the EP satellite to read out and acquire data from the pnCCD module of the focal plane detector.Methods The pnCCD module is complex to control,has a high data throughput,and poses challenges during readout.This paper presents the design and implementation of a data acquisition system specifically for pnCCD and its readout ASIC,CAMEX.The DAQ includes a dedicated front-end module for signal conversion,a control module for powering the pnCCD on and off and managing its sequence,and a signal preprocessing module that performs real-time corrections for offset and common mode on signals acquired by the ADC.Additionally,the offset module allows for in-orbit calculation and updating of the offset.Results The DAQ operates stably in orbit and functions normally,accurately recording the amplitude,position,and arrival time of signals.This capability enables the production of images and energy spectra,which provide robust support for scientific data analysis on the ground.Conclusion The DAQ has achieved readout and data acquisition for the pnCCD module of the focal plane detector,meeting the requirements of the EP satellite’s FXT payload and operating well in orbit.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
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
The Low Energy X-ray telescope(LE) is one of the three main instruments of the Insight-Hard X-ray Modulation Telescope(Insight-HXMT). It is equipped with Swept Charge Device(SCD) sensor arrays with a total geometrical...The Low Energy X-ray telescope(LE) is one of the three main instruments of the Insight-Hard X-ray Modulation Telescope(Insight-HXMT). It is equipped with Swept Charge Device(SCD) sensor arrays with a total geometrical area of 384 cm^2 and an energy band from 0.7 to 13 ke V. In order to evaluate the particle induced X-ray background and the cosmic X-ray background simultaneously, LE adopts collimators to define four types of Field Of Views(FOVs), i.e., 1.6°×6°, 4°×6°, 50°-60°×2°-6 oand the blocked ones which block the X-ray by an aluminum cover. LE is constituted of three detector boxes(LEDs) and an electric control box(LEB) and achieves a good energy resolution of 140 e V@5.9 ke V, an excellent time resolution of 0.98 ms, as well as an extremely low pileup(<1%@18000 cts/s). Detailed performance tests and calibration on the ground have been performed,including energy-channel relation, energy response, detection efficiency and time response.展开更多
As the world's biggest carbon dioxide(CO_(2))emitter and the largest developing country,China faces daunting challenges to peak its emissions before 2030 and achieve carbon neutrality within 40 years.This study fu...As the world's biggest carbon dioxide(CO_(2))emitter and the largest developing country,China faces daunting challenges to peak its emissions before 2030 and achieve carbon neutrality within 40 years.This study fully considered the carbon-neutrality goal and the temperature rise constraints required by the Paris Agreement,by developing six long-term development scenarios,and conducting a quantitative evaluation on the carbon emissions pathways,energy transformation,technology,policy and investment demand for each scenario.This study combined both bottom-up and top-down methodologies,including simulations and analyses of energy consumption of end-use and power sectors(bottom-up),as well as scenario analysis,investment demand and technology evaluation at the macro level(top-down).This study demonstrates that achieving carbon neutrality before 2060 translates to significant efforts and overwhelming challenges for China.To comply with the target,a high rate of an average annual reduction of CO_(2) emissions by 9.3%from 2030 to 2050 is a necessity,which requires a huge investment demand.For example,in the 1.5℃ scenario,an investment in energy infrastructure alone equivalent to 2.6%of that year's GDP will be necessary.The technological pathway towards carbon neutrality will rely highly on both conventional emission reduction technologies and breakthrough technologies.China needs to balance a long-term development strategy of lower greenhouse gas emissions that meets both the Paris Agreement and the long-term goals for domestic economic and social development,with a phased implementation for both its five-year and long-term plans.展开更多
基金supported by Strategic Priority Program on Space Science of Chinese Academy of Sciences,in collaboration with ESA,MPE and CNES(grant Nos.XDA15310303,XDA15310103 and XDA15052100)。
文摘The in-flight instrumental background of the Follow-up X-ray Telescope(FXT)onboard Einstein Probe mis sion is analysed in this work by utilizing observations collected during the performance verification phase and subsequent dedicated filter wheel closed observations.The instrumental backgrounds of the two FXT modules are consistent with each other,with an average rate of~4×10^(-2)counts s^(-1)keV^(-1)in the 0.5-10 keV band for each module.The background is nearly uniformly distributed across the detector area,with a minor increase(<8%)observed along rows.The spatial distribution shows significant modulation by the geomagnetic field.The spectral shapes remain unchanged in 0.5-10 keV at different rates.The long-term temporal variation indicates a periodic change associated with the orbital precession(~57 days).The innovative design of FXT full-frame readout mode enables simultaneous recording of events in both the imaging area(IMG)and the frame store area(FSA)of the pnCCD.FSA event rates show a strong linear correlation with the IMG,based on which the IMG instrumental background modeling is established.
基金supported by the Strategic Priority Research Program on Space Science,the Chinese Academy of Sciences,grant No.XDA15310103.
文摘The Follow-up X-ray Telescope(FXT)is one of the main scientific instruments on board the Einstein Probe astronomical satellite,which was launched in 2024 January.FXT consists of two Wolter I type nested telescopes(FXT-A and FXT-B)with a focal length of 1600 mm.The focal plane detector employs a PNCCD with 384×384 pixels.The timing mode of FXT serves as the primary operating mode for fast X-ray timing observations.To evaluate and validate the timing performance of FXT prior to launch,a comprehensive timing calibration was performed at the 100 m X-ray test facility.By simulating various periodic Crab-like profiles using the Grid Controlled X-ray Tube(GCXT)in conjunction with a pulsar simulation module,it was verified that the relative time accuracy of FXT exceeds 5×10^(−9).Furthermore,employing GCXT with a voltage pulse generation module enabled the determination of the time resolutions for FXT-A and FXT-B,recorded as 45.6±2.7μs and 47.1±2.8μs,respectively.An absolute timing calibration for FXT-B was carried out using the GCXT and a time interval analyzer,revealing a measured time delay of 3.9±2.1μs for FXT-B.
基金Thanks for the support of the Special Fund for Global Green Development and Climate Change of Tsinghua University Education Foundation and the Energy Foundation.
文摘1.Introduction 2020 is an unusual year in which the COVID-19 pandemic has raged through the globe,infecting tens of millions of people and killing hundreds of thousands.The pandemic has not only wreaked havoc on public health systems,economic activities,and people's lives,but also has greatly affected and will continue to reshape the world's political,economic,and trade patterns.
基金supported in part by the grant from National Natural Science Foundation of China(82171818,81703048,82041019,and 82101919)the grant from Defense Industrial Technology Development Program of China(JCKY2020802B001)Beijing Municipal Science and Technology Commission(Z201100005420024)。
文摘Recombinant adenovirus serotype 5(Ad5)vector has been widely applied in vaccine development targeting infectious diseases,such as Ebola virus disease and coronavirus disease 2019(COVID-19).However,the high prevalence of preexisting anti-vector immunity compromises the immunogenicity of Ad5-based vaccines.Thus,there is a substantial unmet need to minimize preexisting immunity while improving the insert-induced immunity of Ad5 vectors.Herein,we address this need by utilizing biocompatible nanoparticles to modulate Ad5–host interactions.We show that positively charged human serum albumin nanoparticles((+)HSAnp),which are capable of forming a complex with Ad5,significantly increase the transgene expression of Ad5 in both coxsackievirus–adenovirus receptor-positive and-negative cells.Furthermore,in charge-and dose-dependent manners,Ad5/(+)HSAnp complexes achieve robust(up to227-fold higher)and long-term(up to 60 days)transgene expression in the lungs of mice following intranasal instillation.Importantly,in the presence of preexisting anti-Ad5 immunity,complexed Ad5-based Ebola and COVID-19 vaccines significantly enhance antigen-specific humoral response and mucosal immunity.These findings suggest that viral aggregation and charge modification could be leveraged to engineer enhanced viral vectors for vaccines and gene therapies.
基金Supported by the National Natural Science Foundation of China(Grant No.12001174)the Natural Science Foundation of Shandong Province(Grant No.ZR2023MA008)。
文摘In this paper,we introduce the notion of a generalized weak group-like algebra which is designed to cover finite groupoid algebras and group-like algebras.Then we construct a list of examples and show that a generalized weak group-like algebra can be regarded as a generalized weak bi-Frobenius algebra.Moreover,we discuss when a generalized weak bi-Frobenius algebra is a groupoid algebra.Finally,we give the classifications of low-dimensional generalized weak group-like algebras.
基金supported by the Strategic Priority Research Program on Space Science,the Chinese Academy of Sciences(Grant No.XDA 15310103).
文摘Background:The Einstein Probe mission is an astronomical satellite developed in China,focusing on time-domain astronomy in the soft X-ray energy band.A key payload of this mission is the follow-up X-ray telescope(FXT),which is the result of international collaboration between China and Europe.The FXT features gold-coated nickel Wolter-I-type focusing mirrors and utilizes PNCCD detectors for imaging and spectroscopy in the focal plane.Methods:We reviewed the seven-year development history of the FXT.Initially,the configuration of the FXT consisted of a single telescope unit in 2017,but it later evolved into a dual-unit setup.Building on the successful design of eROSITA,the FXT team has innovatively introduced new operational modes for the PNCCD.FXT team also developed an ultra-compact helium pulse tube refrigerator,which cools the PNCCD down to-90℃.Additionally,various passive shielding measures have been implemented to protect against high-energy charged particles and enhance radiation resistance.These advancements have significantly improved the overall performance and reliability of the FXT.Results and conclusion:The ground calibrations and tests of the FXT demonstrate that its primary performance meets the established design goals.The FXT has exhibited outstanding performance in orbit,establishing itself as one of the space X-ray telescopes with considerable international influence.
基金This research was supported by the Ministry of Science and Technology of the People’s Republic of China[Grant number.2018YFC 1509001]the National Natural Science Foundation of China[Grant number.72174105]by Tsinghua University-INDITEX Sustainable Development Fund[Grant number.TISD201909].
文摘Presently,the full implementation of the negotiations and collaborations under the Paris Agreement faces new key problems and severe challenges.These problems and challenges include the following:how to honor the principle of“common but differentiated responsibilities”to facilitate a comprehensive,balanced,and effective implementation of the key elements of the Paris Agreement,such as adaptation,mitigation,finance,technology,capacity building,and transparency;how to uphold and maintain the status of China and other emerging countries as developing countries in light of the requirements of the United Nations Framework Convention on Climate Change and the historical responsibilities of these countries;and how to assess the goal of limiting the global temperature increase to 1.5℃and what constitutes an equitable carbon mitigation pathway for different types of countries.Developed countries and developing countries have drastically diverging views on carbon border adjustment measures for trade with developing countries proposed by several developed countries such as the European Union.Developed countries have demonstrated obvious intentions and actions designed to weaken and neglect the principle of“common but differentiated responsibilities”,to impose mitigation pressure on developing countries,to shift the responsibilities for emissions onto others,and to pass on the costs of mitigation.The maneuvering among different types of countries and interest groups has become increasingly intense.In response,China must maintain its strategic focus,adhere to the goals and principles established by the Paris Agreement,stick to its strategic positioning as a developing country,solidify strategic support from the developing world,and safeguard the legitimate rights and interests of developing countries.China played a conducive role in facilitating the Paris Agreement and has become an active participant,contributor,and leader in global climate governance.China must continue to follow Xi Jinping Thought on Socialism with Chinese Characteristics for a New Era and its conception of ecological civilization and the concept of building a community of common destiny,to actively lead the cooperation process in the construction of a global climate governance system characterized by equity,justice,and win-win collaborations,and to promote compliance with the Paris Agreement.At the same time,China should accelerate the green,low-carbon,circular transformation of its economy;accelerate the coordinated governance of the economy,environment,and climate change;and formulate and implement a long-term low-carbon development strategy.By the middle of the 21st century,while achieving the goal of building a great modern socialist country,China can also achieve a deep decarbonization development path that is in line with the goal of limiting the global temperature increase to well below 2°C and pursuing efforts to limit the increase to 1.5℃.
基金supported by the Einstein-Probe(EP)Program which is funded by the Strategic Priority Research Program of the Chinese Academy of Sciences Grant No.XDA15310103.
文摘Purpose The follow-up X-ray telescope(FXT)is one of the two payloads of the Einstein Probe(EP),consisting of the upper composite with the X-ray mirror module as the core,the lower composite with the pnCCD module as the core,and the interface structure.The FXT thermal control subsystem is responsible for the thermal design,thermal implementations,and testing of the entire FXT payload thermal control.Methods A design approach is adopted with passive thermal control technology as the main method and active thermal control technology as a supplement for common components.The X-ray mirror modules are high-precision optical components,utilizing active closed-loop temperature control to ensure high precision and stability.The pnCCD detectors operate at a stable low temperature,with refrigerators used to cool the detector houses,ensuring they can operate under stable low-temperature conditions.The hot ends of the refrigerators are connected to the external radiator panels through heat pipes for heat dissipation.Results The thermal control subsystem of FXT is operating properly in-orbit.All component temperatures meet the design requirements.Conclusion After multiple rounds of design and test verification,FXT was successfully launched with EP and completed in-orbit testing.During the in-orbit testing phase of EP,the function of the FXT thermal control subsystem works well.The temperatures of the components and units are normal.This paper introduces the design of FXT thermal control and the in-orbit performance of the thermal control subsystem.
基金supported by the Strategic Priority Research Program on Space Science,the Chinese Academy of Sciences(Grant No.XDA 15310103).
文摘Purpose The Einstein Probe(EP)satellite is a space X-ray satellite for time-domain astronomy and high-energy astrophysics.The precision control of the optical structure directly affects the imaging quality and positioning accuracy of the Follow-up X-ray Telescope(FXT),playing a crucial role in achieving the on-orbit scientific objectives of the FXT.Higher positioning accuracy makes it easier to identify corresponding bodies for the discovery and positioning of transient sources.Accurate positioning is beneficial for follow-up observations in other bands,such as optical spectroscopy.Methods This article mainly introduces the precision control methods and processes of the FXT optical structure,which have been tested and verified through satellite test.The on-orbit source positioning accuracy of the FXT telescope is within 20 arcseconds(90% confidence level),meeting the requirements of the FXT mission.Results and Conclusion To ensure the accuracy of the EP satellite’s FXT optical structure,measures such as component processing control,installation control,and posttest adjustments are taken on the ground to ensure that the detector mounting position,optical axis deviation,and other precision indicators before and after the satellite lever test meet the design requirements.After a successful launch,through on-orbit calibration,the FXT-A and FXT-B optical axis pointing direction deviation is 39 arcseconds,and the source positioning error is better than 3'' at 68% confidence level.FXT optical structure meets all the requirements from design,processing,installation,etc.,successfully meeting scientific needs.
基金supported by the Strategic Priority Research Program on Space Science,the Chinese Academy of Sciences(Grant No.XDA 15310103).
文摘Purpose The Einstein Probe(EP)is an X-ray astronomical satellite designed for time-domain astronomy.The Follow-up X-ray Telescope(FXT)is an important payload on the EP.The FXT’s detector utilizes a pn-junction charge-coupled device(pnCCD),which is currently the fastest-readout X-ray CCD worldwide.The design and implementation of a dedicated power-supply and monitoring module constitute a key aspect in the development of the detector system.Methods The FXT comprises several components,including the electric control box(EC-Box),the detector electronics box(DE-Box),and the focusing camera.The detector module of the focusing camera consists of two primary components:the pnCCD and the multi-channel analog signal processing chip known as the CAMEX(CMOS amplifier and multiplexer)ASIC.The CAMEX ASIC is used for the readout of the pnCCD signals.The operation of the detector module requires a sophisticated power-supply module.This paper details the design and implementation of a dedicated power-supply and monitoring module for the detector module.Based on the voltage requirements of the detector module,the power-supply module has been designed to include switchable,adjustable,and programmable functions.The monitoring module includes voltage,current,and temperature monitoring based on the different types of monitoring.Results The power-supply and monitoring module operates reliably and performs effectively in orbit,meeting the requirements of the FXT payload on the EP satellite.Conclusion The power-supply and monitoring module has successfully provided a stable power-supply and monitoring module for the detector module.It operates effectively in orbit,ensuring that the detector system achieves optimal performance.
基金the support of the National Natural Science Foundation of China(Grant No.12333007)the International Partnership Program of Chinese Academy of Sciences(Grant No.113111KYSB20190020)+4 种基金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 n.2017-14-H.O.by INAF and INFN under project REDSOXsupport from the Deutsche Zentrum für Luft-und Raumfahrt,the German Aerospace Center(DLR)support from MINECO grant ESP2017-82674-R and FEDER funds.
文摘In this paper,we present the current status of the enhanced X-ray Timing and Polarimetry mission,which has been fully approved for launch in 2030.eXTP is a space science mission designed to study fundamental physics under extreme conditions of matter density,gravity,and magnetism.The mission aims at determining the equation of state of matter at supra-nuclear density,measuring the effects of quantum electro-dynamics,and understanding the dynamics of matter in strong-field gravity.In addition to investigating fundamental physics,the eXTP mission is poised to become a leading observatory for time-domain and multi-messenger astronomy in the 2030s,as well as providing observations of unprecedented quality on a variety of galactic and extragalactic objects.After briefly introducing the history and a summary of the scientific objectives of the eXTP mission,this paper presents a comprehensive overview of:(1)the cutting-edge technology,technical specifications,and anticipated performance of the mission’s scientific instruments;(2)the full mission profile,encompassing spacecraft design,operational capabilities,and ground segment infrastructure.
基金supported by the Strategic Priority Research Program on Space Science,the Chinese Academy of Sciences Grant No.XDA15310103.
文摘Background The Einstein probe(EP)is an X-ray astronomical satellite dedicated to time-domain astronomy and high-energy astrophysics.Initiated at the end of 2017,it was successfully launched on January 9,2024.The follow-up X-ray telescope(FXT)is a key payload on the EP satellite.The FXT employs PNCCD as its focal plane detector.Its electronic components include the electronic control box(EC-Box),the detector electronics boxes(DE-Box),the refrigerator controller,the movement mechanisms controller,and the temperature control instrument.Methods The FXT conducted functional performance tests in-orbit as planned,including three operating modes of the detector,energy detection range,and energy resolution.Results Since FXT became operational in orbit,all electronic equipment has been working stably.The FXT has an energy detection range of 0.3-10 keV,with an energy resolution of approximately 92 eV@1.25 keV,and an electronic noise of about 3.3e^(-).
基金supported by the Einstein-Probe(EP)Program which is funded by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA1531010301).
文摘Purpose:Mini-magnets of FXT are designed to deflect low-energy electrons that are incident into the camera aperture area,preventing them from reaching the focal plane detector and thereby reducing the noises they generate.Methods:By employing a combination of theoretical calculations and experimental measurements,the parameters of the FXT mini-magnets were obtained,including magnetic field distributions,magnetic moment results,and electron deflection efficiency.Results:The structural and magnetic models of the optimized mini-magnets are presented.Distributions of magnetic field intensity on different planes within the camera aperture are compared with the measured results from the FXT flight models(FMs).The results for the total and separated magnetic moment of two sets of FMs are also provided.Additionally,the deflection efficiency for 25 keV electrons is calculated under various incident conditions.Conclusion:The FMs of mini-magnets show good performance,with the measured values of magnetic field distributions being highly consistent with the theoretical values.A perfect result for total magnetic moment of less than 10mA·m^(2)has been achieved,far better than requirement of 100mA·m^(2).The calculated electron deflection efficiency reached over 99.88%,effectively fulfilling the objective of deflecting electrons in space.
基金based on data obtained with Einstein Probe,a space mission supported by Strategic Priority Program on Space Science of Chinese Academy of Sciences,in collaboration with ESA,MPE and CNES(Grant No.XDA15310000)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB0550200)+5 种基金the National Key R&D Program of China(Grant No.2022YFF0711500)the support by the National Natural Science Foundation of China(Grant Nos.12333004,12321003,12103065,12373040,12021003,12025303,12393814,and 12203071)the China Manned Space Project(Grant Nos.CMS-CSST-2021-A13,and CMS-CSST-2021-B11)the Youth Innovation Promotion Association of the Chinese Academy of Sciencessupported by a Ramón y Cajal fellowship(Grant No.RYC2021-030888-I)financial support from AGAUR,CSIC,MCIN and AEI 10.13039/501100011033(Grant Nos.PID2023-151307NB-I00,PIE 20215AT016,CEX2020-001058-M,and 2021-SGR-01270)。
文摘We report the discovery of a peculiar X-ray transient,EP240408a,by Einstein Probe(EP)and follow-up studies made with EP,Swift,NICER,GROND,ATCA and other ground-based multiwavelength telescopes.The new transient was first detected with Wide-field X-ray Telescope(WXT)on board EP on April 8th,2024,manifested in an intense yet brief X-ray flare lasting for 12 s.The flare reached a peak flux of 3:9×10^(−9) erg cm^(−2) s^(−1) in 0.5-4 keV,∼300 times brighter than the underlying X-ray emission detected throughout the observation.Rapid and more precise follow-up observations by EP/FXT,Swift and NICER confirmed the finding of this new transient.Its X-ray spectrum is non-thermal in 0.5-10 keV,with a power-law photon index varying within 1.8-2.5.The X-ray light curve shows a plateau lasting for∼4 d,followed by a steep decay till becoming undetectable∼10 d after the initial detection.Based on its temporal property and constraints from previous EP observations,an unusual timescale in the range of 7-23 d is found for EP240408a,which is intermediate between the commonly found fast and long-term transients.No counterparts have been found in optical and near-infrared,with the earliest observation at 17 h after the initial X-ray detection,suggestive of intrinsically weak emission in these bands.We demonstrate that the remarkable properties of EP240408a are inconsistent with any of the transient types known so far,by comparison with,in particular,jetted tidal disruption events,gamma-ray bursts,X-ray binaries and fast blue optical transients.The nature of EP240408a thus remains an enigma.We suggest that EP240408a may represent a new type of transients with intermediate timescales of the order of∼10 d.The detection and follow-ups of more of such objects are essential for revealing their origin.
基金supported by National Natural Science Foundation of China(Nos.12471033,12201188,12001174)Natural Science Foundation of Henan Province(No.242300421389)+1 种基金China Postdoctoral Science Foundation(No.2022M711076)Postdoctoral Research Grant in Henan Province(No.202103090).
文摘In order to induce the associative classical Yang-Baxter equations of any weight,we present the notion of an antisymmetric infinitesimal(ASI)bialgebra of weightλ,extending the ASI bialgebras to any weight.Meanwhile,we consider the BiHomdeformation of the bialgebra above,which leads to the major research object that we need:nonhomogeneous associative BiHom-classical Yang-Baxter equations(abhcYBes).Subsequently,we focus on the characterizations and constructions of abhcYBes from generalized O-operators and weighted Rota-Baxter operators,which can be seen as a generalization of the main results in[Adv.Theor.Math.Phys.26(2022)19652009].
基金supported by the Strategic Priority Research Program on Space Science,the Chinese Academy of Sciences(Grant No.XDA 1531010301).
文摘Purpose Design and implement a system within the detector electronic box of the FXT payload on the EP satellite to read out and acquire data from the pnCCD module of the focal plane detector.Methods The pnCCD module is complex to control,has a high data throughput,and poses challenges during readout.This paper presents the design and implementation of a data acquisition system specifically for pnCCD and its readout ASIC,CAMEX.The DAQ includes a dedicated front-end module for signal conversion,a control module for powering the pnCCD on and off and managing its sequence,and a signal preprocessing module that performs real-time corrections for offset and common mode on signals acquired by the ADC.Additionally,the offset module allows for in-orbit calculation and updating of the offset.Results The DAQ operates stably in orbit and functions normally,accurately recording the amplitude,position,and arrival time of signals.This capability enables the production of images and energy spectra,which provide robust support for scientific data analysis on the ground.Conclusion The DAQ has achieved readout and data acquisition for the pnCCD module of the focal plane detector,meeting the requirements of the EP satellite’s FXT payload and operating well in orbit.
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the Strategic Priority Research Program on Space Science,the Chinese Academy of Sciences(Grant No.XDA040102).
文摘The Low Energy X-ray telescope(LE) is one of the three main instruments of the Insight-Hard X-ray Modulation Telescope(Insight-HXMT). It is equipped with Swept Charge Device(SCD) sensor arrays with a total geometrical area of 384 cm^2 and an energy band from 0.7 to 13 ke V. In order to evaluate the particle induced X-ray background and the cosmic X-ray background simultaneously, LE adopts collimators to define four types of Field Of Views(FOVs), i.e., 1.6°×6°, 4°×6°, 50°-60°×2°-6 oand the blocked ones which block the X-ray by an aluminum cover. LE is constituted of three detector boxes(LEDs) and an electric control box(LEB) and achieves a good energy resolution of 140 e V@5.9 ke V, an excellent time resolution of 0.98 ms, as well as an extremely low pileup(<1%@18000 cts/s). Detailed performance tests and calibration on the ground have been performed,including energy-channel relation, energy response, detection efficiency and time response.
文摘As the world's biggest carbon dioxide(CO_(2))emitter and the largest developing country,China faces daunting challenges to peak its emissions before 2030 and achieve carbon neutrality within 40 years.This study fully considered the carbon-neutrality goal and the temperature rise constraints required by the Paris Agreement,by developing six long-term development scenarios,and conducting a quantitative evaluation on the carbon emissions pathways,energy transformation,technology,policy and investment demand for each scenario.This study combined both bottom-up and top-down methodologies,including simulations and analyses of energy consumption of end-use and power sectors(bottom-up),as well as scenario analysis,investment demand and technology evaluation at the macro level(top-down).This study demonstrates that achieving carbon neutrality before 2060 translates to significant efforts and overwhelming challenges for China.To comply with the target,a high rate of an average annual reduction of CO_(2) emissions by 9.3%from 2030 to 2050 is a necessity,which requires a huge investment demand.For example,in the 1.5℃ scenario,an investment in energy infrastructure alone equivalent to 2.6%of that year's GDP will be necessary.The technological pathway towards carbon neutrality will rely highly on both conventional emission reduction technologies and breakthrough technologies.China needs to balance a long-term development strategy of lower greenhouse gas emissions that meets both the Paris Agreement and the long-term goals for domestic economic and social development,with a phased implementation for both its five-year and long-term plans.
