Prof.Wing-Huen Ip,a world-renown scientist in cometary physics,planetary science,solar system evolution and exoplanets,took the post of the Executive Director of the International Space Science Institute一Beijing(ISSI...Prof.Wing-Huen Ip,a world-renown scientist in cometary physics,planetary science,solar system evolution and exoplanets,took the post of the Executive Director of the International Space Science Institute一Beijing(ISSI-BJ)in June.As the only partner of the well-known International Space Science Institute(ISSI)in Bern outside Switzerland,ISSI-BJ has adopted the same tools as ISSI to facilitate international cooperation and academic exchanges:workshops,forums,and others that rely on in-person communications.展开更多
Space weathering is an important surface process that occurs on the Moon and other airless bodies, especially those that have no magnetic field. The optical effects of the Moon's space weathering have largely been...Space weathering is an important surface process that occurs on the Moon and other airless bodies, especially those that have no magnetic field. The optical effects of the Moon's space weathering have largely been investigated in the laboratory for lunar samples and lunar analogues. However, duplication of pristine regolith on Earth is not possible. Here we report on space weathering from the unique perspective of the "Yutu" rover, which was part of the Chang'e-3(CE-3) mission, building on our previous work.Measurement of the visually undisturbed uppermost regolith as well as locations that have been affected by rocket exhaust from the spacecraft by the Visible-Near Infrared Spectrometer(VNIS) revealed that the returned samples provide biased information about the pristine lunar regolith. The uppermost surficial regolith is much more weathered than the regolith immediately below, and the finest fraction is rich in space weathered products. These materials are very dark and attenuated throughout the visible and near-infrared(VNIR) wavelengths, hence reducing the reflectance and masking the absorption features. The effects on the spectral slope caused by space weathering are wavelength-dependent: the visible and near-infrared continuum slope(VNCS) increases while the visible slope(VS) decreases. In the visible wavelengths, the optical effects of space weathering and Ti O_2 are identical: both reduce albedo and blue the spectra. This suggests that a new Ti O_2 abundance algorithm is needed. Optical maturity indices are related to composition and hence only locally meaningful. Since optical remote sensing can only sense the uppermost few microns of regolith and since this surface tends to be very weathered, the interpretation of surface composition using optical remote sensing data needs to be carefully evaluated. Sampling the uppermost surface is suggested.展开更多
With Venus Express magnetic field measurements at 32 Hz from 2006 to 2012, we investigate statistically the magnetic fluctuations in the near-Venusian space. The global spatial distribution of their spectral scaling f...With Venus Express magnetic field measurements at 32 Hz from 2006 to 2012, we investigate statistically the magnetic fluctuations in the near-Venusian space. The global spatial distribution of their spectral scaling features is presented in MHD and kinetic regimes. It can be observed that turbulence is a common phenomenon in the solar wind in both regimes. The solar wind MHD turbulence is modified at the Venusian bow shock;MHD turbulence is absent in the Venusian magnetosheath but present at the magnetosheath boundary layer. Pre-existing kinetic turbulence from the far upstream solar wind is modified in the near solar wind region, while kinetic turbulence can be extensively observed throughout the Venusian magnetosheath and in some regions of the induced magnetosphere. Our results reveal that, in the near-Venusian space, energy cascade can be developed at the boundary between magnetosheath and wake, and the turbulence-related dissipation of magnetic energy occurs extensively in the magnetosheath and the induced magnetosphere.展开更多
In this report, we summarize the needs of space weather models, and recommend that developing operational prediction models, rather than transitioning from research to operation, is a more feasible and critical way fo...In this report, we summarize the needs of space weather models, and recommend that developing operational prediction models, rather than transitioning from research to operation, is a more feasible and critical way for space weather services in the near future. Operational models for solar wind speed, geomagnetic indices, magnetopause, plasma sheet energetic electrons, inner boundary of ion plasma sheet, energetic electrons in outer radiation belt, and thermospheric density at low Earth orbit, have been developed and will be introduced briefly here. Their applications made a big progress in space weather services during the past two years in China.展开更多
As the role of missions and experiments carried out in outer space becomes more and more essential in our understanding of many earthly problems,such as resource management,environmental problems,and disaster manageme...As the role of missions and experiments carried out in outer space becomes more and more essential in our understanding of many earthly problems,such as resource management,environmental problems,and disaster management,as well as space science questions,thanks to their lower cost and faster development process CubeSats can benefit humanity and therefore,young scientists and engineers have been motivated to research and develop new CubeSat missions.Not very long after their inception,CubeSats have evolved to become accepted platforms for scientific and commercial applications.The last couple of years showed that they are a feasible tool for conducting scientific experiments,not only in the Earth orbit but also in the interplanetary space.For many countries,a CubeSat mission could prompt the community and young teams around the world to build the national capacity to launch and operate national space missions.This paper presents an overview of the key scientific and engineering gateways opened up to the younger scientific community by the advent and adaptation of new technology into CubeSat missions.The role of cooperation and the opportunities for capacity-building and education are also explored.Thus,the present article also aims to provide useful recommendations to scientists,early-career researchers,engineers,students,and anyone who intends to explore the potential and opportunities offered by CubeSats and CubeSats-based missions.展开更多
The joint European Space Agency and Chinese Academy of Sciences Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)mission will explore global dynamics of the magnetosphere under varying solar wind and interplane...The joint European Space Agency and Chinese Academy of Sciences Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)mission will explore global dynamics of the magnetosphere under varying solar wind and interplanetary magnetic field conditions,and simultaneously monitor the auroral response of the Northern Hemisphere ionosphere.Combining these large-scale responses with medium and fine-scale measurements at a variety of cadences by additional ground-based and space-based instruments will enable a much greater scientific impact beyond the original goals of the SMILE mission.Here,we describe current community efforts to prepare for SMILE,and the benefits and context various experiments that have explicitly expressed support for SMILE can offer.A dedicated group of international scientists representing many different experiment types and geographical locations,the Ground-based and Additional Science Working Group,is facilitating these efforts.Preparations include constructing an online SMILE Data Fusion Facility,the discussion of particular or special modes for experiments such as coherent and incoherent scatter radar,and the consideration of particular observing strategies and spacecraft conjunctions.We anticipate growing interest and community engagement with the SMILE mission,and we welcome novel ideas and insights from the solar-terrestrial community.展开更多
Space science offers a unique opportunity to open dialogue between countries,independently of their political system. In the early 1990s,Dr. Roger-Maurice Bonnet,Director of the Science Program of ESA received a lette...Space science offers a unique opportunity to open dialogue between countries,independently of their political system. In the early 1990s,Dr. Roger-Maurice Bonnet,Director of the Science Program of ESA received a letter from a group of Chinese scientists in response to an invitation,to cooperate on the ESA CLUSTER mission. That event marked the initiation of space cooperation between ESA and China. He is very disappointed about that the partners of the International Space Station(USA,Russia,Europe,Japan,Canada) would not agree on accepting China as one of their partners,and China has to develop its own space station with its own means.展开更多
Vast magnetospheric regions are mapped along the field lines to the narrow latitudinal band of the polar/auroral regions. Therefore monitoring of solar wind energy dissipation into the ionosphere at auroral latitudes ...Vast magnetospheric regions are mapped along the field lines to the narrow latitudinal band of the polar/auroral regions. Therefore monitoring of solar wind energy dissipation into the ionosphere at auroral latitudes gives unique opportunities to study geomagnetic disturbances in their complexity from a relatively well-localized vantage point. Here we introduce and present the current state of a recently proposed science project for coordinated monitoring of high-latitude activity with the EISCAT (European Incoherent Scatter) radar array supported by ground-based magnetometer and optical data and ENA (Energetic Neutral Atom) observation from the CINEMA (Cube-Sat for Ions, Neutrals, Electrons and Magnetic field) satellite system.展开更多
Within the context of the proton-neutron quasi-particle random phase approximation(pn-QRPA)model and TALYS v1.96 code,the radiative capture(^(99)Tc(n,γ)^(100)Tc)and stellar weak interaction(^(99)Tc→^(99)Ru+e^(−)+ν_...Within the context of the proton-neutron quasi-particle random phase approximation(pn-QRPA)model and TALYS v1.96 code,the radiative capture(^(99)Tc(n,γ)^(100)Tc)and stellar weak interaction(^(99)Tc→^(99)Ru+e^(−)+ν_(e))rates were computed during thermal pulses operating in asymptotic giant branch stars.The Maxwellian average cross-section(MACS)and neutron capture rates for the^(99)Tc(n,γ)^(100)Tc process are analyzed within the context of statistical code TALYS v1.96.The effect of nuclear level density(NLD)andγ-strength functions on MACS and neutron capture rates has been examined.The model-based computations for MACS provided an insightful contrast to prior investigated findings.The sensitivity of stellar weak interaction rates to different densities and temperatures is investigated using the pn-QRPA model.The impact of thermally populated excited states on electron emission(β^(−))rates in^(99)Tc is extensively examined.Additionally,a comparison is made between the study of the stellarβ^(−)decay rates and the thermal neutron capture rates.It is found that at T_(9)=0.26 the thermal neutron capture rates(λ_((n,γ)))and the temperature dependent stellarβ^(−)decay rates( λ_(β-))cross each other.However,at higher temperatures,theλ(n,γ)are found to be higher than λ_(β-).展开更多
Theβ-decay properties of^(67-80)As nuclei have been investigated within the framework of the proton-neutron quasi-particle random phase approximation(pn-QRPA)model.The nuclear deformation obtained from the finite ran...Theβ-decay properties of^(67-80)As nuclei have been investigated within the framework of the proton-neutron quasi-particle random phase approximation(pn-QRPA)model.The nuclear deformation obtained from the finite range droplet model is used as an input parameter in the pn-QRPA model for the analysis ofβ-decay properties including Gamow-Teller strength distributions,log ft,β-decay half-lives and stellarβ^(±)decay rates.The predicted log ft values were fairly consistent with the observed data.The computedβ-decay half-lives matched the measured values by a factor of 10.The stellar rates were compared with the shell model outcomes.At high densities and temperatures,theβ^(+)and electron capture rates had a finite contribution.However,theβ^(-)and positron capture rates are only significant at high temperatures and low densities.The pn-QRPA rates outperformed the shell model rates by a factor of 22 or more.展开更多
The nuclear ground state properties of even-even^(106-120)Zr nuclei have been investigated within the framework of the relativistic mean field(RMF)approach.The RMF model with density-dependent DDME2 and DDPC1 interact...The nuclear ground state properties of even-even^(106-120)Zr nuclei have been investigated within the framework of the relativistic mean field(RMF)approach.The RMF model with density-dependent DDME2 and DDPC1 interactions is utilized for the calculation of potential energy curves,the nuclear ground-state deformation parameters(β_(2)),neutron separation energies(S_(n)and S_(2n))and neutron skin thickness(rnp)of selected Zr isotopes.Later,theβ-decay properties of Zr isotopes were studied using the proton-neutron quasi-particle random phase approximation(pn-QRPA)model.These include Gamow-Teller strength distributions,β-decay half-lives and stellar electron emission/positron capture rates.Theβ2 values computed from the RMF model were employed in the pn-QRPA model as an input parameter for the calculations ofβ-decay properties for even-even 106-120Zr nuclei.The stellar rates were computed using the pn-QRPA framework with three different types of deformation parameters.Only at high temperature(T_(9)≥2)and low density(ρYe≤10^(7)g cm^(−3))values,the sum of electron emission and positron capture rates has a sizeable contribution(with positive exponents)to the stellar rates.展开更多
We present the first theoretical study on heavy-flavor jet angularities(λ_(α)^(κ))in Pb+Pb collisions at√SNN=5.02 Te V.The initial production of heavy-flavor jets was carried out using the POWHEG+PYTHIA8 prescript...We present the first theoretical study on heavy-flavor jet angularities(λ_(α)^(κ))in Pb+Pb collisions at√SNN=5.02 Te V.The initial production of heavy-flavor jets was carried out using the POWHEG+PYTHIA8 prescription.In contrast,the SHELL transport model describes jet evolution in the quark-gluon plasma(QGP).In p+p collisions,we observed narrower angularity distributions for D ^(0)-tagged jets than for inclusive jets,consistent with the ALICE preliminary results.We then demonstrate that jet quenching in the QGP slightly widens the angularity distribution of D ^(0)-tagged jets in Pb+Pb collisions relative to that in p+p collisions for a jet transverse momentum of 10<pch/T,jet<20 Ge V/c.In contrast,the angularity distributions of the inclusive and D ^(0)-tagged jets become narrower in Pb+Pb collisions relative to p+p atpch/T,jet>20 Ge V/c because of the strong influence of selection bias.Additionally,by comparing the average angularities<λ_(α)^(κ)>of the inclusive,D ^(0)-tagged,and B ^(0)-tagged jets with varyingαandκ,we show that the larger the quark mass,the lower the jet’s<λ_(α)^(κ)>values are.As a result of the slenderer initial distribution,we predict that compared with inclusive jets,heavy-flavor jets,especially B~0-tagged ones,will suffer stronger modifications of<λ_(α)^(κ)>in Pb+Pb relative to p+p at 10<pch/T,jet<20 Ge V/c.For a larger jet radius,a more significant broadening of the jet angularities was predicted because of the enhanced contribution of the wide-angle particles.展开更多
A novel automatic seamless stitching method is presented. Compared to the traditional method, it can speed the processing and minimize the utilization of human resources to produce global lunar map. Meanwhile, a new g...A novel automatic seamless stitching method is presented. Compared to the traditional method, it can speed the processing and minimize the utilization of human resources to produce global lunar map. Meanwhile, a new global image map of the Moon with spatial resolution of -120 m has been completed by the proposed method from Chang＇E-1 CCD image data.展开更多
P-wave and S-wave receiver function analyses have been performed along a profile consisted of 27 broadband seismic stations to image the crustal and upper mantle discontinuities across Northeast China. The results sho...P-wave and S-wave receiver function analyses have been performed along a profile consisted of 27 broadband seismic stations to image the crustal and upper mantle discontinuities across Northeast China. The results show that the average Moho depth varies from about 37 km beneath the Daxing＇anling orogenic belt in the west to about 33 km beneath the Songliao Basin, and to about 35 km beneath the Changbai mountain region in the east. Our results reveal that the Moho is generally flat beneath the Daxing＇anling region and a remarkable Moho offset （about 4 km） exists beneath the basin-mountain boundary, the Daxing＇anling-Taihang Gravity Line. Beneath the Tanlu faults zone, which seperates the Songliao Basin and Changbai region, the Moho is uplift and the crustal thick- ness changes rapidly. We interpret this feature as that the Tanlu faults might deeply penetrate into the upper mantle, and facilitate the mantle upwelling along the faults during the Cenozoic era. The average depth of the lithosphereasthenosphere boundary （LAB） is - 80 km along the profile which is thinner than an average thickness of a continental lithosphere. The LAB shows an arc-like shape in the basin, with the shallowest part approximately beneath the center of the basin. The uplift LAB beneath the basin might be related to the extensive lithospheric stretching in the Mesozoic. In the mantle transition zone, a structurally complicated 660 km discontinuity with a maximum 35 km depression beneath the Changbai region is observed. The 35 km depression is roughly coincident with the location of the stagnant western pacific slab on top of the 660 km discontinuity revealed by the recent P wave tomography.展开更多
Climate change may affect water resources by altering various processes in natural ecosystems. Dynamic and statistical downscaling methods are commonly used to assess the impacts of climate change on water resources. ...Climate change may affect water resources by altering various processes in natural ecosystems. Dynamic and statistical downscaling methods are commonly used to assess the impacts of climate change on water resources. Objectively, both methods have their own advantages and disadvantages. In the present study, we assessed the impacts of climate change on water resources during the future periods (2020–2029 and 2040–2049) in the upper reaches of the Kaidu River Basin, Xinjiang, China, and discussed the uncertainties in the research processes by integrating dynamic and statistical downscaling methods (regional climate models (RCMs) and general circulation modes (GCMs)) and utilizing these outputs. The reference period for this study is 1990–1999. The climate change trend is represented by three bias-corrected RCMs (i.e., Hadley Centre Global Environmental Model version 3 regional climate model (HadGEM3-RA), Regional Climate Model version 4 (RegCM4), and Seoul National University Meso-scale Model version 5 (SUN-MM5)) and an ensemble of GCMs on the basis of delta change method under two future scenarios (RCP4.5 and RCP8.5). We applied the hydrological SWAT (Soil and Water Assessment Tool) model which uses the RCMs/GCMs outputs as input to analyze the impacts of climate change on the stream flow and peak flow of the upper reaches of the Kaidu River Basin. The simulation of climate factors under future scenarios indicates that both temperature and precipitation in the study area will increase in the future compared with the reference period, with the largest increase of annual mean temperature and largest percentage increase of mean annual precipitation being of 2.4°C and 38.4%, respectively. Based on the results from bias correction of climate model outputs, we conclude that the accuracy of RCM (regional climate model) simulation is much better for temperature than for precipitation. The percentage increase in precipitation simulated by the three RCMs is generally higher than that simulated by the ensemble of GCMs. As for the changes in seasonal precipitation, RCMs exhibit a large percentage increase in seasonal precipitation in the wet season, while the ensemble of GCMs shows a large percentage increase in the dry season. Most of the hydrological simulations indicate that the total stream flow will decrease in the future due to the increase of evaporation, and the maximum percentage decrease can reach up to 22.3%. The possibility of peak flow increasing in the future is expected to higher than 99%. These results indicate that less water is likely to be available in the upper reaches of the Kaidu River Basin in the future, and that the temporal distribution of flow may become more concentrated.展开更多
文摘Prof.Wing-Huen Ip,a world-renown scientist in cometary physics,planetary science,solar system evolution and exoplanets,took the post of the Executive Director of the International Space Science Institute一Beijing(ISSI-BJ)in June.As the only partner of the well-known International Space Science Institute(ISSI)in Bern outside Switzerland,ISSI-BJ has adopted the same tools as ISSI to facilitate international cooperation and academic exchanges:workshops,forums,and others that rely on in-person communications.
基金supported by the Key Research Program of the Chinese Academy of Sciences (XDPB11)the Strategic Priority Research Program on Space Science of the Chinese Academy of Sciences (XDA15020302)+2 种基金the National Natural Science Foundation of China (41422110)the Macao Science and Technology Development Fund (103/2017/A and 119/2017/A3)Minor Planet Foundation of Purple Mountain Observatory
文摘Space weathering is an important surface process that occurs on the Moon and other airless bodies, especially those that have no magnetic field. The optical effects of the Moon's space weathering have largely been investigated in the laboratory for lunar samples and lunar analogues. However, duplication of pristine regolith on Earth is not possible. Here we report on space weathering from the unique perspective of the "Yutu" rover, which was part of the Chang'e-3(CE-3) mission, building on our previous work.Measurement of the visually undisturbed uppermost regolith as well as locations that have been affected by rocket exhaust from the spacecraft by the Visible-Near Infrared Spectrometer(VNIS) revealed that the returned samples provide biased information about the pristine lunar regolith. The uppermost surficial regolith is much more weathered than the regolith immediately below, and the finest fraction is rich in space weathered products. These materials are very dark and attenuated throughout the visible and near-infrared(VNIR) wavelengths, hence reducing the reflectance and masking the absorption features. The effects on the spectral slope caused by space weathering are wavelength-dependent: the visible and near-infrared continuum slope(VNCS) increases while the visible slope(VS) decreases. In the visible wavelengths, the optical effects of space weathering and Ti O_2 are identical: both reduce albedo and blue the spectra. This suggests that a new Ti O_2 abundance algorithm is needed. Optical maturity indices are related to composition and hence only locally meaningful. Since optical remote sensing can only sense the uppermost few microns of regolith and since this surface tends to be very weathered, the interpretation of surface composition using optical remote sensing data needs to be carefully evaluated. Sampling the uppermost surface is suggested.
基金supported by NSFC grants 41904156, 41974205, 41774171, 41574173, 41774167 and 41804157the Science and Technology Development Fund of Macao SAR (008/2016/A1 and 039/2013/A2)+3 种基金the China Postdoctoral Science Foundation (2019M651271)the financial support of the Shenzhen Science and Technology Research Program (JCYJ20170811154933612 and JCYJ20180306171918617)the 111 Project (B18017)supported by CAS Center for Excellence in Comparative Planetology
文摘With Venus Express magnetic field measurements at 32 Hz from 2006 to 2012, we investigate statistically the magnetic fluctuations in the near-Venusian space. The global spatial distribution of their spectral scaling features is presented in MHD and kinetic regimes. It can be observed that turbulence is a common phenomenon in the solar wind in both regimes. The solar wind MHD turbulence is modified at the Venusian bow shock;MHD turbulence is absent in the Venusian magnetosheath but present at the magnetosheath boundary layer. Pre-existing kinetic turbulence from the far upstream solar wind is modified in the near solar wind region, while kinetic turbulence can be extensively observed throughout the Venusian magnetosheath and in some regions of the induced magnetosphere. Our results reveal that, in the near-Venusian space, energy cascade can be developed at the boundary between magnetosheath and wake, and the turbulence-related dissipation of magnetic energy occurs extensively in the magnetosheath and the induced magnetosphere.
文摘In this report, we summarize the needs of space weather models, and recommend that developing operational prediction models, rather than transitioning from research to operation, is a more feasible and critical way for space weather services in the near future. Operational models for solar wind speed, geomagnetic indices, magnetopause, plasma sheet energetic electrons, inner boundary of ion plasma sheet, energetic electrons in outer radiation belt, and thermospheric density at low Earth orbit, have been developed and will be introduced briefly here. Their applications made a big progress in space weather services during the past two years in China.
文摘As the role of missions and experiments carried out in outer space becomes more and more essential in our understanding of many earthly problems,such as resource management,environmental problems,and disaster management,as well as space science questions,thanks to their lower cost and faster development process CubeSats can benefit humanity and therefore,young scientists and engineers have been motivated to research and develop new CubeSat missions.Not very long after their inception,CubeSats have evolved to become accepted platforms for scientific and commercial applications.The last couple of years showed that they are a feasible tool for conducting scientific experiments,not only in the Earth orbit but also in the interplanetary space.For many countries,a CubeSat mission could prompt the community and young teams around the world to build the national capacity to launch and operate national space missions.This paper presents an overview of the key scientific and engineering gateways opened up to the younger scientific community by the advent and adaptation of new technology into CubeSat missions.The role of cooperation and the opportunities for capacity-building and education are also explored.Thus,the present article also aims to provide useful recommendations to scientists,early-career researchers,engineers,students,and anyone who intends to explore the potential and opportunities offered by CubeSats and CubeSats-based missions.
基金supported by Royal Society grant DHFR1211068funded by UKSA+14 种基金STFCSTFC grant ST/M001083/1funded by STFC grant ST/W00089X/1supported by NERC grant NE/W003309/1(E3d)funded by NERC grant NE/V000748/1support from NERC grants NE/V015133/1,NE/R016038/1(BAS magnetometers),and grants NE/R01700X/1 and NE/R015848/1(EISCAT)supported by NERC grant NE/T000937/1NSFC grants 42174208 and 41821003supported by the Research Council of Norway grant 223252PRODEX arrangement 4000123238 from the European Space Agencysupport of the AUTUMN East-West magnetometer network by the Canadian Space Agencysupported by NASA’s Heliophysics U.S.Participating Investigator Programsupport from grant NSF AGS 2027210supported by grant Dnr:2020-00106 from the Swedish National Space Agencysupported by the German Research Foundation(DFG)under number KR 4375/2-1 within SPP"Dynamic Earth"。
文摘The joint European Space Agency and Chinese Academy of Sciences Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)mission will explore global dynamics of the magnetosphere under varying solar wind and interplanetary magnetic field conditions,and simultaneously monitor the auroral response of the Northern Hemisphere ionosphere.Combining these large-scale responses with medium and fine-scale measurements at a variety of cadences by additional ground-based and space-based instruments will enable a much greater scientific impact beyond the original goals of the SMILE mission.Here,we describe current community efforts to prepare for SMILE,and the benefits and context various experiments that have explicitly expressed support for SMILE can offer.A dedicated group of international scientists representing many different experiment types and geographical locations,the Ground-based and Additional Science Working Group,is facilitating these efforts.Preparations include constructing an online SMILE Data Fusion Facility,the discussion of particular or special modes for experiments such as coherent and incoherent scatter radar,and the consideration of particular observing strategies and spacecraft conjunctions.We anticipate growing interest and community engagement with the SMILE mission,and we welcome novel ideas and insights from the solar-terrestrial community.
文摘Space science offers a unique opportunity to open dialogue between countries,independently of their political system. In the early 1990s,Dr. Roger-Maurice Bonnet,Director of the Science Program of ESA received a letter from a group of Chinese scientists in response to an invitation,to cooperate on the ESA CLUSTER mission. That event marked the initiation of space cooperation between ESA and China. He is very disappointed about that the partners of the International Space Station(USA,Russia,Europe,Japan,Canada) would not agree on accepting China as one of their partners,and China has to develop its own space station with its own means.
基金supported by the BK21 Plus program through the National Research Foundation(NRF)funded by the Ministry of Education of Korea.
文摘Vast magnetospheric regions are mapped along the field lines to the narrow latitudinal band of the polar/auroral regions. Therefore monitoring of solar wind energy dissipation into the ionosphere at auroral latitudes gives unique opportunities to study geomagnetic disturbances in their complexity from a relatively well-localized vantage point. Here we introduce and present the current state of a recently proposed science project for coordinated monitoring of high-latitude activity with the EISCAT (European Incoherent Scatter) radar array supported by ground-based magnetometer and optical data and ENA (Energetic Neutral Atom) observation from the CINEMA (Cube-Sat for Ions, Neutrals, Electrons and Magnetic field) satellite system.
基金the financial support of the Higher Education Commission Pakistan through project number 20-15394/NRPU/R&D/HEC/2021.
文摘Within the context of the proton-neutron quasi-particle random phase approximation(pn-QRPA)model and TALYS v1.96 code,the radiative capture(^(99)Tc(n,γ)^(100)Tc)and stellar weak interaction(^(99)Tc→^(99)Ru+e^(−)+ν_(e))rates were computed during thermal pulses operating in asymptotic giant branch stars.The Maxwellian average cross-section(MACS)and neutron capture rates for the^(99)Tc(n,γ)^(100)Tc process are analyzed within the context of statistical code TALYS v1.96.The effect of nuclear level density(NLD)andγ-strength functions on MACS and neutron capture rates has been examined.The model-based computations for MACS provided an insightful contrast to prior investigated findings.The sensitivity of stellar weak interaction rates to different densities and temperatures is investigated using the pn-QRPA model.The impact of thermally populated excited states on electron emission(β^(−))rates in^(99)Tc is extensively examined.Additionally,a comparison is made between the study of the stellarβ^(−)decay rates and the thermal neutron capture rates.It is found that at T_(9)=0.26 the thermal neutron capture rates(λ_((n,γ)))and the temperature dependent stellarβ^(−)decay rates( λ_(β-))cross each other.However,at higher temperatures,theλ(n,γ)are found to be higher than λ_(β-).
基金funded by Taif University,Saudi Arabia,Project No.(TU-DSPP-2024-33)。
文摘Theβ-decay properties of^(67-80)As nuclei have been investigated within the framework of the proton-neutron quasi-particle random phase approximation(pn-QRPA)model.The nuclear deformation obtained from the finite range droplet model is used as an input parameter in the pn-QRPA model for the analysis ofβ-decay properties including Gamow-Teller strength distributions,log ft,β-decay half-lives and stellarβ^(±)decay rates.The predicted log ft values were fairly consistent with the observed data.The computedβ-decay half-lives matched the measured values by a factor of 10.The stellar rates were compared with the shell model outcomes.At high densities and temperatures,theβ^(+)and electron capture rates had a finite contribution.However,theβ^(-)and positron capture rates are only significant at high temperatures and low densities.The pn-QRPA rates outperformed the shell model rates by a factor of 22 or more.
基金funded by Taif University,Saudi Arabia,Project No.(TU-DSPP-2024-33).
文摘The nuclear ground state properties of even-even^(106-120)Zr nuclei have been investigated within the framework of the relativistic mean field(RMF)approach.The RMF model with density-dependent DDME2 and DDPC1 interactions is utilized for the calculation of potential energy curves,the nuclear ground-state deformation parameters(β_(2)),neutron separation energies(S_(n)and S_(2n))and neutron skin thickness(rnp)of selected Zr isotopes.Later,theβ-decay properties of Zr isotopes were studied using the proton-neutron quasi-particle random phase approximation(pn-QRPA)model.These include Gamow-Teller strength distributions,β-decay half-lives and stellar electron emission/positron capture rates.Theβ2 values computed from the RMF model were employed in the pn-QRPA model as an input parameter for the calculations ofβ-decay properties for even-even 106-120Zr nuclei.The stellar rates were computed using the pn-QRPA framework with three different types of deformation parameters.Only at high temperature(T_(9)≥2)and low density(ρYe≤10^(7)g cm^(−3))values,the sum of electron emission and positron capture rates has a sizeable contribution(with positive exponents)to the stellar rates.
基金supported by the Guangdong Major Project of Basic and Applied Basic Research(Grant No.2020B0301030008)the National Natural Science Foundation of China(Grant Nos.11935007 and 12035007)+1 种基金supported by the Open Foundation of the Key Laboratory of Quark and Lepton Physics(MOE)(Grant No.QLPL2023P01)the Talent Scientific Star-up Foundation of the China Three Gorges University(CTGU)(Grant No.2024RCKJ013)。
文摘We present the first theoretical study on heavy-flavor jet angularities(λ_(α)^(κ))in Pb+Pb collisions at√SNN=5.02 Te V.The initial production of heavy-flavor jets was carried out using the POWHEG+PYTHIA8 prescription.In contrast,the SHELL transport model describes jet evolution in the quark-gluon plasma(QGP).In p+p collisions,we observed narrower angularity distributions for D ^(0)-tagged jets than for inclusive jets,consistent with the ALICE preliminary results.We then demonstrate that jet quenching in the QGP slightly widens the angularity distribution of D ^(0)-tagged jets in Pb+Pb collisions relative to that in p+p collisions for a jet transverse momentum of 10<pch/T,jet<20 Ge V/c.In contrast,the angularity distributions of the inclusive and D ^(0)-tagged jets become narrower in Pb+Pb collisions relative to p+p atpch/T,jet>20 Ge V/c because of the strong influence of selection bias.Additionally,by comparing the average angularities<λ_(α)^(κ)>of the inclusive,D ^(0)-tagged,and B ^(0)-tagged jets with varyingαandκ,we show that the larger the quark mass,the lower the jet’s<λ_(α)^(κ)>values are.As a result of the slenderer initial distribution,we predict that compared with inclusive jets,heavy-flavor jets,especially B~0-tagged ones,will suffer stronger modifications of<λ_(α)^(κ)>in Pb+Pb relative to p+p at 10<pch/T,jet<20 Ge V/c.For a larger jet radius,a more significant broadening of the jet angularities was predicted because of the enhanced contribution of the wide-angle particles.
基金supported by the Science and Technology Development Fund of Macao (Nos. 004/2011/A1 and 015/2010/A)the National High Technology Research and Development Program (No. 2010AA122202)
文摘A novel automatic seamless stitching method is presented. Compared to the traditional method, it can speed the processing and minimize the utilization of human resources to produce global lunar map. Meanwhile, a new global image map of the Moon with spatial resolution of -120 m has been completed by the proposed method from Chang＇E-1 CCD image data.
文摘P-wave and S-wave receiver function analyses have been performed along a profile consisted of 27 broadband seismic stations to image the crustal and upper mantle discontinuities across Northeast China. The results show that the average Moho depth varies from about 37 km beneath the Daxing＇anling orogenic belt in the west to about 33 km beneath the Songliao Basin, and to about 35 km beneath the Changbai mountain region in the east. Our results reveal that the Moho is generally flat beneath the Daxing＇anling region and a remarkable Moho offset （about 4 km） exists beneath the basin-mountain boundary, the Daxing＇anling-Taihang Gravity Line. Beneath the Tanlu faults zone, which seperates the Songliao Basin and Changbai region, the Moho is uplift and the crustal thick- ness changes rapidly. We interpret this feature as that the Tanlu faults might deeply penetrate into the upper mantle, and facilitate the mantle upwelling along the faults during the Cenozoic era. The average depth of the lithosphereasthenosphere boundary （LAB） is - 80 km along the profile which is thinner than an average thickness of a continental lithosphere. The LAB shows an arc-like shape in the basin, with the shallowest part approximately beneath the center of the basin. The uplift LAB beneath the basin might be related to the extensive lithospheric stretching in the Mesozoic. In the mantle transition zone, a structurally complicated 660 km discontinuity with a maximum 35 km depression beneath the Changbai region is observed. The 35 km depression is roughly coincident with the location of the stagnant western pacific slab on top of the 660 km discontinuity revealed by the recent P wave tomography.
基金supported by the Natural Science Foundation of Xinjiang Uygur Autonomous Region (2015211B031)the Coordinated Regional Downscaling Experiment-East Asia (CORDEX-EA) projectthe Coupled Model Inter-comparison Project Phase 5 (CMIP5) project for providing dynamic downscaling RCMs and GCMs data free of charge
文摘Climate change may affect water resources by altering various processes in natural ecosystems. Dynamic and statistical downscaling methods are commonly used to assess the impacts of climate change on water resources. Objectively, both methods have their own advantages and disadvantages. In the present study, we assessed the impacts of climate change on water resources during the future periods (2020–2029 and 2040–2049) in the upper reaches of the Kaidu River Basin, Xinjiang, China, and discussed the uncertainties in the research processes by integrating dynamic and statistical downscaling methods (regional climate models (RCMs) and general circulation modes (GCMs)) and utilizing these outputs. The reference period for this study is 1990–1999. The climate change trend is represented by three bias-corrected RCMs (i.e., Hadley Centre Global Environmental Model version 3 regional climate model (HadGEM3-RA), Regional Climate Model version 4 (RegCM4), and Seoul National University Meso-scale Model version 5 (SUN-MM5)) and an ensemble of GCMs on the basis of delta change method under two future scenarios (RCP4.5 and RCP8.5). We applied the hydrological SWAT (Soil and Water Assessment Tool) model which uses the RCMs/GCMs outputs as input to analyze the impacts of climate change on the stream flow and peak flow of the upper reaches of the Kaidu River Basin. The simulation of climate factors under future scenarios indicates that both temperature and precipitation in the study area will increase in the future compared with the reference period, with the largest increase of annual mean temperature and largest percentage increase of mean annual precipitation being of 2.4°C and 38.4%, respectively. Based on the results from bias correction of climate model outputs, we conclude that the accuracy of RCM (regional climate model) simulation is much better for temperature than for precipitation. The percentage increase in precipitation simulated by the three RCMs is generally higher than that simulated by the ensemble of GCMs. As for the changes in seasonal precipitation, RCMs exhibit a large percentage increase in seasonal precipitation in the wet season, while the ensemble of GCMs shows a large percentage increase in the dry season. Most of the hydrological simulations indicate that the total stream flow will decrease in the future due to the increase of evaporation, and the maximum percentage decrease can reach up to 22.3%. The possibility of peak flow increasing in the future is expected to higher than 99%. These results indicate that less water is likely to be available in the upper reaches of the Kaidu River Basin in the future, and that the temporal distribution of flow may become more concentrated.
