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Sequestration of helium and xenon via iron-halide compounds in early Earth 被引量:1
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作者 Jurong Zhang Hanyu Liu +1 位作者 Changfeng Chen Yanming Ma 《Matter and Radiation at Extremes》 SCIE EI CSCD 2024年第3期83-88,共6页
The terrestrial abundance anomalies of helium and xenon suggest the presence of deep-Earth reservoirs of these elements,which has led to great interest in searching for materials that can host these usually unreactive... The terrestrial abundance anomalies of helium and xenon suggest the presence of deep-Earth reservoirs of these elements,which has led to great interest in searching for materials that can host these usually unreactive elements.Here,using an advanced crystal structure search approach in conjunction with first-principles calculations,we show that several Xe/He-bearing iron halides are thermodynamically stable in a broad region of P–T phase space below 60 GPa.Our results present a compelling case for sequestration of He and Xe in the early Earth and may suggest their much wider distribution in the present Earth than previously believed.These findings offer insights into key material-based and physical mechanisms for elucidating major geological phenomena. 展开更多
关键词 HALIDE SEARCHING INSIGHT
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Isochrone Fitting of Galactic Globular Clusters—Ⅵ.High-latitude Clusters NGC 5024 (M53),NGC 5053,NGC 5272 (M3),NGC 5466,and NGC7099 (M30)
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作者 G.A.Gontcharov S.S.Savchenko +7 位作者 A.A.Marchuk C.J.Bonatto O.S.Ryutina M.Yu.Khovritchev V.B.Il'in A.V.Mosenkov D.M.Poliakov A.A.Smirnov 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第6期170-190,共21页
We fit various color–magnitude diagrams(CMDs) of the high-latitude Galactic globular clusters NGC 5024(M53),NGC 5053,NGC 5272(M3),NGC 5466,and NGC 7099(M30) by isochrones from the Dartmouth Stellar Evolution Database... We fit various color–magnitude diagrams(CMDs) of the high-latitude Galactic globular clusters NGC 5024(M53),NGC 5053,NGC 5272(M3),NGC 5466,and NGC 7099(M30) by isochrones from the Dartmouth Stellar Evolution Database and Bag of Stellar Tracks and Isochrones for α–enrichment [α/Fe] = +0.4.For the CMDs,we use data sets from Hubble Space Telescope,Gaia,and other sources utilizing,at least,25 photometric filters for each cluster.We obtain the following characteristics with their statistical uncertainties for NGC 5024,NGC 5053,NGC 5272,NGC 5466,and NGC 7099,respectively:metallicities [Fe/H] =-1.93 ± 0.02,-2.08 ± 0.03,-1.60 ± 0.02,-1.95 ± 0.02,and-2.07 ± 0.04 dex with their systematic uncertainty 0.1 dex;ages 13.00 ± 0.11,12.70 ± 0.11,11.63 ± 0.07,12.15 ± 0.11,and 12.80 ± 0.17 Gyr with their systematic uncertainty 0.8 Gyr;distances(systematic uncertainty added) 18.22 ± 0.06 ± 0.60,16.99 ± 0.06 ± 0.56,10.08 ± 0.04 ± 0.33,15.59 ±0.03 ± 0.51,and 8.29 ± 0.03 ± 0.27 kpc;reddenings E(B-V) = 0.023 ± 0.004,0.017 ± 0.004,0.023 ± 0.004,0.023 ± 0.003,and 0.045 ± 0.002 mag with their systematic uncertainty 0.01 mag;extinctions AV= 0.08 ± 0.01,0.06 ± 0.01,0.08 ± 0.01,0.08 ± 0.01,and 0.16 ± 0.01 mag with their systematic uncertainty 0.03 mag,which suggest the total Galactic extinction AV= 0.08 across the whole Galactic dust to extragalactic objects at the North Galactic Pole.The horizontal branch morphology difference of these clusters is explained by their different metallicity,age,mass-loss efficiency,and loss of low-mass members in the evolution of the core-collapse cluster NGC 7099 and loose clusters NGC 5053 and NGC 5466. 展开更多
关键词 (stars:)Hertzsprung Russell and C-M diagrams (ISM:)dust extinction (Galaxy:)globular clusters:general (Galaxy:)globular clusters:individual(NGC 5024 NGC 5053 NGC 5272 NGC 5466 NGC7099)
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Impact of initial fluctuations and nuclear deformations in isobar collisions
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作者 Jian-Fei Wang Hao-Jie Xu Fu-Qiang Wang 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第6期155-162,共8页
Relativistic isobar^(96)_(44)Ru+^(96)_(44)Ru and^(96)_(40)Zr+^(96)_(40)Zrcollisions have revealed intricate differences in their nuclear size and shape,inspiring unconventional studies of nuclear structure using relat... Relativistic isobar^(96)_(44)Ru+^(96)_(44)Ru and^(96)_(40)Zr+^(96)_(40)Zrcollisions have revealed intricate differences in their nuclear size and shape,inspiring unconventional studies of nuclear structure using relativistic heavy ion collisions.In this study,we investigate the relative differences in the mean multiplicityR_(<Nch>)and the secondR_(ε2)and third-order eccentricityR_(ε3)between isobar collisions using initial state Glauber models.It is found that initial fluctuations and nuclear deformations have negligible effects on R_(<Nch>)in most central collisions,while both are important for the R_(ε2)and R_(ε3),the degree of which is sensitive to the underlying nucleonic or sub-nucleonic degree of freedom.These features,compared to real data,may probe the particle production mechanism and the physics underlying nuclear structure. 展开更多
关键词 Relativistic isobar collisions Initial fluctuations Nuclear deformation
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The circuitry landscape of perovskite solar cells:An in-depth analysis
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作者 Siddhi Vinayak Pandey Daniel Prochowicz +4 位作者 Apurba Mahapatra Saravanan Pandiaraj Abdullah N.Alodhayb Seckin Akin Pankaj Yadav 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第7期393-413,共21页
The extensive research and development in perovskite solar cells (PSCs) have rekindled the hopes of converting solar energy into electricity.An elusive understanding of underlying mechanisms is required for the develo... The extensive research and development in perovskite solar cells (PSCs) have rekindled the hopes of converting solar energy into electricity.An elusive understanding of underlying mechanisms is required for the development of efficient PSCs.Over the years,Impedance Spectroscopy (IS) characterization,along with complementary techniques,has proven to be an effective way to understand and analyze the charge transport and recombination at interface and bulk of PSCs.The IS of PSCs have been analyzed,interpreted,and improvised continuously,revealing intricate details about the work.However,there is a lack of centralized source of these details,which make it tougher to account for the generalized approach to understand the device properties.The present work is focused on compiling the research done on various PSC device architectures via IS to construct a comprehensive foundation of information on impedance plots,equivalent circuits,and associated processes. 展开更多
关键词 Impedance Spectroscopy Perovskite solar cells Equivalent Circuits
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Confirmation of a Sub-Saturn-size Transiting Exoplanet Orbiting a G Dwarf:TOI-1194 b and a Very Low Mass Companion Star: TOI-1251 B from TESS
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作者 Jia-Qi Wang Xiao-Jun Jiang +18 位作者 Jie Zheng Hanna Kellermann Arno Riffeser Liang Wang Karen A.Collins Allyson Bieryla Lars A.Buchhave Steve B.Howell Elise Furlan Eric Girardin Joao Gregorio Eric Jensen Felipe Murgas Mesut Yilmaz Sam Quinn Xing Gao Ruo-Yu Zhou Frank Grupp Hui-Juan Wang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第3期129-143,共15页
We report the confirmation of a sub-Saturn-size exoplanet,TOI-1194 b,with a mass of about 0.456+0.055-0.051M_(J),and a very low mass companion star with a mass of about 96.5±1.5 MJ,TOI-1251 B.Exoplanet candidates... We report the confirmation of a sub-Saturn-size exoplanet,TOI-1194 b,with a mass of about 0.456+0.055-0.051M_(J),and a very low mass companion star with a mass of about 96.5±1.5 MJ,TOI-1251 B.Exoplanet candidates provided by the Transiting Exoplanet Survey Satellite(TESS)are suitable for further follow-up observations by ground-based telescopes with small and medium apertures.The analysis is performed based on data from several telescopes worldwide,including telescopes in the Sino-German multiband photometric campaign,which aimed at confirming TESS Objects of Interest(TOIs)using ground-based small-aperture and medium-aperture telescopes,especially for long-period targets.TOI-1194 b is confirmed based on the consistent periodic transit depths from the multiband photometric data.We measure an orbital period of 2.310644±0.000001 days,the radius is 0.767+0.045-0.041RJ and the amplitude of the RV curve is 69.4_(-7.3)^(+7.9)m s^(-1).TOI-1251 B is confirmed based on the multiband photometric and high-resolution spectroscopic data,whose orbital period is 5.963054+0.000002-0.000001days,radius is 0.947+0.035-0.033 R_(J) and amplitude of the RV curve is 9849_(-40)^(+42)ms^(-1). 展开更多
关键词 planets and satellites fundamental parameters-planets and satellites gaseous planets-stars fundamental parameters-stars low-mass-methods data analysis-techniques photometric-techniques spectroscopic
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The ALMA-QUARKS Survey.Ⅱ.The ACA 1.3 mm Continuum Source Catalog and the Assembly of Dense Gas in Massive Star-Forming Clumps
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作者 许峰玮 Ke Wang +30 位作者 Tie Liu Lei Zhu Guido Garay Xunchuan Liu Paul Goldsmith Qizhou Zhang Patricio Sanhueza Shengli Qin Jinhua He Mika Juvela Anandmayee Tej Hongli Liu Shanghuo Li Kaho Morii Siju Zhang Jianwen Zhou Amelia Stutz Neal JEvans Kee-Tae Kim Shengyuan Liu Diego Mardones Guangxing Li Leonardo Bronfman Ken’ichi Tatematsu Chang Won Lee Xing Lu Xiaofeng Mai Sihan Jiao James O.Chibueze Keyun Su Viktor L.Tóth 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第6期119-139,共21页
Leveraging the high resolution,sensitivity,and wide frequency coverage of the Atacama Large Millimeter/submillimeter Array(ALMA),the QUARKS survey,standing for“Querying Underlying mechanisms of massive star formation... Leveraging the high resolution,sensitivity,and wide frequency coverage of the Atacama Large Millimeter/submillimeter Array(ALMA),the QUARKS survey,standing for“Querying Underlying mechanisms of massive star formation with ALMA-Resolved gas Kinematics and Structures”,is observing 139 massive starforming clumps at ALMA Band 6(λ~1.3 mm).This paper introduces the Atacama Compact Array(ACA)7 m data of the QUARKS survey,describing the ACA observations and data reduction.Combining multiwavelength data,we provide the first edition of QUARKS atlas,offering insights into the multiscale and multiphase interstellar medium in high-mass star formation.The ACA 1.3 mm catalog includes 207 continuum sources that are called ACA sources.Their gas kinetic temperatures are estimated using three formaldehyde transitions with a non-LTE radiation transfer model,and the mass and density are derived from a dust emission model.The ACA sources are massive(16–84 percentile values of 6–160 M_(⊙)),gravity-dominated(M∝R^(1.1))fragments within massive clumps,with supersonic turbulence(M>1)and embedded star-forming protoclusters.We find a linear correlation between the masses of the fragments and the massive clumps,with a ratio of 6%between the two.When considering fragments as representative of dense gas,the ratio indicates a dense gas fraction(DGF)of 6%,although with a wide scatter ranging from 1%to 10%.If we consider the QUARKS massive clumps to be what is observed at various scales,then the size-independent DGF indicates a self-similar fragmentation or collapsing mode in protocluster formation.With the ACA data over four orders of magnitude of luminosity-to-mass ratio(L/M),we find that the DGF increases significantly with L/M,which indicates clump evolutionary stage.We observed a limited fragmentation at the subclump scale,which can be explained by a dynamic global collapse process. 展开更多
关键词 stars:formation ISM:kinematics and dynamics ISM:clouds stars:protostars
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Extinction of Light in the Galactic Halo: First Observational Evidence of the Interaction of Light and Dark Matter
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作者 Charles H. McGruder III 《Journal of Modern Physics》 2024年第8期1144-1198,共55页
We study the distribution of quasars on the celestial sphere according to ground-based SDSS and space-based WISE and Gaia observations. All distributions as a function of galactic latitude, b, exhibit a decrease in qu... We study the distribution of quasars on the celestial sphere according to ground-based SDSS and space-based WISE and Gaia observations. All distributions as a function of galactic latitude, b, exhibit a decrease in quasar frequency well outside the dust in and near the galactic plane. We prove that the observed decrease in quasar frequency at high galactic latitudes is not accompanied by reddening, meaning that it can not be caused by dust. The scattering of light by the circumgalactic gas is negligible because the Thomson scattering cross section is very small. We conclude the observed scattering of light must be caused by dark matter in the galactic halo. We determine the mass and charge of dark matter particles. If the dark matter particle is a fermion its mass, mDMand charge eDM=δe, where e is the elementary charge are: mDM=3.2×10−2eV and δ=3.856×10−5. If however the dark matter particle is spinless then: mDM=0.511eV and δ=2.132×10−4. These values for the charge of a dark matter particle are orders of magnitude higher than the upper limit of the neutrino charge according to laboratory experiments. Consequently, dark matter particles are not charged neutrinos. Since dark matter particles are charged, they must emit and absorb electromagnetic radiation. However, PDM~δ2, or: PDM~1.487×10−9Pe, where Peis the power output of a single electron. 展开更多
关键词 Milky Way Dark Matter Halo (1049)
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Trimming the Degrees of Freedom via a K^(+) Flux Rectifier for Safe and Long‑Life Potassium‑Ion Batteries 被引量:1
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作者 Xianhui Yi Apparao MRao +1 位作者 Jiang Zhou Bingan Lu 《Nano-Micro Letters》 SCIE EI CAS CSCD 2023年第11期157-171,共15页
High degrees of freedom(DOF)for K^(+)movement in the electrolytes is desirable,because the resulting high ionic conductivity helps improve potassium-ion batteries,yet requiring support from highly free and flammable o... High degrees of freedom(DOF)for K^(+)movement in the electrolytes is desirable,because the resulting high ionic conductivity helps improve potassium-ion batteries,yet requiring support from highly free and flammable organic solvent molecules,seriously affecting battery safety.Here,we develop a K^(+)flux rectifier to trim K ion’s DOF to 1 and improve electrochemical properties.Although the ionic conductivity is compromised in the K^(+)flux rectifier,the overall electrochemical performance of PIBs was improved.An oxidation stability improvement from 4.0 to 5.9 V was realized,and the formation of dendrites and the dissolution of organic cathodes were inhibited.Consequently,the K||K cells continuously cycled over 3,700 h;K||Cu cells operated stably over 800 cycles with the Coulombic efficiency exceeding 99%;and K||graphite cells exhibited high-capacity retention over 74.7%after 1,500 cycles.Moreover,the 3,4,9,10-perylenetetracarboxylic diimide organic cathodes operated for more than 2,100 cycles and reached year-scale-cycling time.We fabricated a 2.18 Ah pouch cell with no significant capacity fading observed after 100 cycles. 展开更多
关键词 Electrolytes Degrees of freedom SAFE Coulombic efficiency Potassium-ion batteries
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X-ray imaging of 30 year old wine grape wood reveals cumulative impacts of rootstocks on scion secondary growth and Ravaz index 被引量:1
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作者 ZoëMigicovsky Michelle Y.Quigley +18 位作者 Joey Mullins Tahira Ali Joel F.Swift Anita Rose Agasaveeran Joseph D.Dougherty Brendan Michael Grant Ilayda Korkmaz Maneesh Reddy Malpeddi Emily L.McNichol Andrew W.Sharp Jackie L.Harris Danielle R.Hopkins Lindsay M.Jordan Misha T.Kwasniewski R.Keith Striegler Asia L.Dowtin Stephanie Stotts Peter Cousins Daniel H.Chitwood 《Horticulture Research》 SCIE CSCD 2023年第1期31-44,共14页
Annual rings from 30 year old vines in a California rootstock trial were measured to determine the effects of 15 different rootstocks on Chardonnay and Cabernet Sauvignon scions.Viticultural traits measuring vegetativ... Annual rings from 30 year old vines in a California rootstock trial were measured to determine the effects of 15 different rootstocks on Chardonnay and Cabernet Sauvignon scions.Viticultural traits measuring vegetative growth,yield,berry quality,and nutrient uptake were collected at the beginning(1995 to 1999)and end(2017 to 2020)of the lifetime of a vineyard initially planted in 1991 and removed in 2021.X-ray Computed Tomography(CT)was used to measure ring widths in 103 vines.Ring width was modeled as a function of ring number using a negative exponential model.Early and late wood ring widths,cambium width,and scion trunk radius were correlated with 27 traits.Modeling of annual ring width shows that scions alter the width of the first rings but that rootstocks alter the decay of later rings,consistently shortening ring width throughout the lifetime of the vine.Ravaz index,juice pH,photosynthetic assimilation and transpiration rates,and instantaneous water use efficiency are correlated with scion trunk radius.Ultimately,our research indicates that rootstocks modulate secondary growth over years,altering physiology and agronomic traits.Rootstocks act in similar but distinct ways from climate to modulate ring width,which borrowing techniques from dendrochronology,can be used to monitor both genetic and environmental effects in woody perennial crop species. 展开更多
关键词 RINGS LIFETIME removed
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New Cases of Superflares on Slowly Rotating Solar-type Stars and Large Amplitude Superflares in G-and M-type Main Sequence Stars
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作者 A.K.Althukair D.Tsiklauri 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2023年第10期308-323,共16页
In our previous work,we searched for superflares on different types of stars while focusing on G-type dwarfs using entire Kepler data to study statistical properties of the occurrence rate of superflares.Using these n... In our previous work,we searched for superflares on different types of stars while focusing on G-type dwarfs using entire Kepler data to study statistical properties of the occurrence rate of superflares.Using these new data,as a byproduct,we found 14 cases of superflare detection on 13 slowly rotating Sun-like stars with rotation periods of24.5–44 days.This result supports the earlier conclusion by others that the Sun may possibly undergo a surprise superflare.Moreover,we found 12 and seven new cases of detection of exceptionally large amplitude superflares on six and four main sequence stars of G-and M-type,respectively.No large-amplitude flares were detected in A,F or K main sequence stars.Here we present preliminary analysis of these cases.The superflare detection,i.e.,an estimation of flare energy,is based on a more accurate method compared to previous studies.We fit an exponential decay function to flare light curves and study the relation between e-folding decay time,τ,versus flare amplitude and flare energy.We find that for slowly rotating Sun-like stars,large values ofτcorrespond to small flare energies and small values ofτcorrespond to high flare energies considered.Similarly,τis large for small flare amplitudes andτis small for large amplitudes considered.However,there is no clear relation between these parameters for large amplitude superflares in the main sequence G-and M-type stars,as we could not establish clear functional dependence between the parameters via standard fitting algorithms. 展开更多
关键词 stars:activity stars:flare stars:rotation stars:solar-type stars:statistics Sun:flares
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Prediction of Short Stellar Activity Cycles using Derived and Established Empirical Relations between Activity and Rotation Periods
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作者 A.K.Althukair D.Tsiklauri 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2023年第11期125-135,共11页
In our previous work,we investigated the occurrence rate of super-flares on various types of stars and their statistical properties,with a particular focus on G-type dwarfs,using entire Kepler data.The said study also... In our previous work,we investigated the occurrence rate of super-flares on various types of stars and their statistical properties,with a particular focus on G-type dwarfs,using entire Kepler data.The said study also considered how the statistics change with stellar rotation period,which in turn,had to be determined.Using such new data,as a by-product,we found 138 Kepler IDs of F-and G-type main sequence stars with rotation periods less than a day(P_(rot)<1 day).On one hand,previous studies have revealed short activity cycles in F-type and G-type stars and the question investigated was whether or not short-term activity cycles are a common phenomenon in these stars.On the other hand,extensive studies exist which establish an empirical connection between a star's activity cycle and rotation periods.In this study,we compile all available Kepler data with P_(rot)<1 day,and rely on an established empirical relation between P_(cyc)and P_(rot)with the aim to provide predictions for very short 5.09≤P_(cyc)≤38.46 day cases in a tabular form.We propose an observation to measure P_(cyc)using a monitoring program of stellar activity(e.g.,activity-related chromospheric emission S-index)or a similar means for the Kepler IDs found in this study in order put the derived empirical relations between P_(cyc)and P_(rot)derived here to the test.We also propose an alternative method for measuring very short P_(cyc),using flare-detection algorithms applied to future space mission data. 展开更多
关键词 stars:activity stars:flare stars:rotation stars:solar-type stars:statistics Sun:flares
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Estimating the subsolar magnetopause position from soft X-ray images using a low-pass image filter 被引量:1
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作者 Hyangpyo Kim Hyunju K.Connor +9 位作者 Jaewoong Jung Brian M.Walsh David Sibeck Kip D.Kuntz Frederick S.Porter Catriana K.Paw U Rousseau A.Nutter Ramiz Qudsi Rumi Nakamura Michael Collier 《Earth and Planetary Physics》 EI CSCD 2024年第1期173-183,共11页
The Lunar Environment heliospheric X-ray Imager(LEXI)and Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)missions will image the Earth’s dayside magneto pause and cusps in soft X-rays after their respective l... The Lunar Environment heliospheric X-ray Imager(LEXI)and Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)missions will image the Earth’s dayside magneto pause and cusps in soft X-rays after their respective launches in the near future,to specify glo bal magnetic reconnection modes for varying solar wind conditions.To suppo rt the success of these scientific missions,it is critical to develop techniques that extract the magnetopause locations from the observed soft X-ray images.In this research,we introduce a new geometric equation that calculates the subsolar magnetopause position(RS)from a satellite position,the look direction of the instrument,and the angle at which the X-ray emission is maximized.Two assumptions are used in this method:(1)The look direction where soft X-ray emissions are maximized lies tangent to the magnetopause,and(2)the magnetopause surface near the subsolar point is almost spherical and thus RSis nea rly equal to the radius of the magneto pause curvature.We create synthetic soft X-ray images by using the Open Geospace General Circulation Model(OpenGGCM)global magnetohydrodynamic model,the galactic background,the instrument point spread function,and Poisson noise.We then apply the fast Fourier transform and Gaussian low-pass filte rs to the synthetic images to re move noise and obtain accurate look angles for the soft X-ray pea ks.From the filte red images,we calculate RS and its accuracy for different LEXI locations,look directions,and solar wind densities by using the OpenGGCM subsolar magnetopause location as ground truth.Our method estimates RS with an accuracy of<0.3 RE when the solar wind density exceeds>10 cm-3.The accuracy improves for greater solar wind densities and during southward interplanetary magnetic fields.The method ca ptures the magnetopause motion during southwa rd interplaneta ry magnetic field turnings.Consequently,the technique will enable quantitative analysis of the magnetopause motion and help reveal the dayside reconnection modes for dynamic solar wind conditions.This technique will suppo rt the LEXI and SMILE missions in achieving their scientific o bjectives. 展开更多
关键词 soft X-ray MAGNETOPAUSE RECONNECTION low-pass filter LEXI SMILE
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Discrimination of pp solar neutrinos and^(14)C double pile-up events in a large-scale LS detector
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作者 Guo-Ming Chen Xin Zhang +5 位作者 Ze-Yuan Yu Si-Yuan Zhang Yu Xu Wen-Jie Wu Yao-Guang Wang Yong-Bo Huang 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2023年第9期69-81,共13页
As a unique probe,the precision measurement of pp solar neutrinos is important for studying the sun’s energy mechanism as it enables monitoring the thermodynamic equilibrium and studying neutrino oscillations in the ... As a unique probe,the precision measurement of pp solar neutrinos is important for studying the sun’s energy mechanism as it enables monitoring the thermodynamic equilibrium and studying neutrino oscillations in the vacuum-dominated region.For a large-scale liquid scintillator detector,a bottleneck for pp solar neutrino detection is the pile-up events of intrinsic14C decay.This paper presents a few approaches to discriminating between pp solar neutrinos and ^(14)C pile-up events by considering the differences in their time and spatial distributions.In this study,a Geant4-based Monte Carlo simulation is conducted.Multivariate analysis and deep learning technology are adopted to investigate the capability of ^(14)C pile-up reduction.The BDTG (boosted decision trees with gradient boosting) model and VGG network demonstrate good performance in discriminating pp solar neutrinos and ^(14)C double pile-up events.Under the ^(14)C concentration assumption of 5×10-18g/g,the signal significance can achieve 10.3 and 15.6 using the statistics of only one day.In this case,the signal efficiency for discrimination using the BDTG model while rejecting 99.18% ^(14)C double pile-up events is 51.1%,and that for the case where the VGG network is used while rejecting 99.81%of the ^(14)C double pile-up events is 42.7%. 展开更多
关键词 Liquid scintillator detector pp solar neutrinos 14C pile-up Multivariate analysis Deep learning
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In-plane uniaxial-strain tuning of superconductivity and charge-density wave in CsV_(3)Sb_(5)
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作者 杨晓冉 唐绮 +8 位作者 周秋韵 王怀平 李意 付雪 张加文 宋宇 袁辉球 戴鹏程 鲁兴业 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第12期468-473,共6页
The kagome superconductor CsV_(3)Sb_(5) with exotic electronic properties has attracted substantial research interest,and the interplay between the superconductivity and the charge-density wave is crucial for understa... The kagome superconductor CsV_(3)Sb_(5) with exotic electronic properties has attracted substantial research interest,and the interplay between the superconductivity and the charge-density wave is crucial for understanding its unusual electronic ground state.In this work,we performed resistivity and AC magnetic susceptibility measurements on CsV_(3)Sb_(5) single crystals uniaxially-strained along[100]and[110]directions.We find that the uniaxial-strain tuning effect of T_(c)(dT_(c)/dε)and T_(CDW)(dT_(CDW)/dε)are almost identical along these distinct high-symmetry directions.These findings suggest the in-plane uniaxial-strain-tuning of T_(c) and T_(CDW)in CsV_(3)Sb_(5) are dominated by associated c-axis strain,whereas the response to purely in-plane strains is likely small. 展开更多
关键词 kagome metal SUPERCONDUCTIVITY charge-density wave uniaxial-strain
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Electrical geophysical evaluation of susceptibility to flooding in University of Nigeria, Nsukka main campus and its environs, Southeastern Nigeria
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作者 Daniel Nnaemeka Obiora Johnson Cletus Ibuot 《Journal of Groundwater Science and Engineering》 2023年第4期422-434,共13页
Flooding occurs when rainfall exceeds the absorption capacity of soil and causes significant environmental consequences.In this study,electrical resistivity techniques were employed to assess the flood susceptibility ... Flooding occurs when rainfall exceeds the absorption capacity of soil and causes significant environmental consequences.In this study,electrical resistivity techniques were employed to assess the flood susceptibility of the study area by examining variations in electrical properties.Prior to flooding,Vertical Electrical Sounding(VES)and Electrical Resistivity Tomography(ERT)profiles were conducted to determine the variations in resistivity within subsurface lithologies exposed to the injected current.The injected current penetrated the subsurface units characterised by resistivity ranging from 190.5Ω·m to 6,775.7Ω·m,42.3Ω·m to 7,297.4Ω·m,and 320.2Ω·m to 24,433.3Ω·m in the first,second and third layers,respectively.These layers were identified as lateritic topsoil,medium-coarse brownish grained sand,and coarse pebbly blackish sand,respectively.The calculated reflection coefficients between layers 1,2,and 3 reveal alternation in layers with values ranging from−0.04 to 0.66 and 0.36 to 0.95 for and,respectively.The transverse resistivity,longitudinal resistivity and anisotropy ranged from 243.59Ω·m to 24,115.42Ω·m,199.61Ω·m to 14,950.76Ω·m,and 1.02 to 2.14.Models derived from the ERT profiles reveal variations in resistivity,pinpointing areas of low resistivity which correspond to waterlogged and impermeable layers.The result of this study underscores the importance of integrated resistivity techniques in the study of floods,as it provides valuable insights into flood behaviour,and subsurface dynamics. 展开更多
关键词 Anisotropy Vertical electrical sounding Electrical resistivity tomography Geoelectric layer Permeability
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Classifying Globular Clusters and Applying them to Estimate the mass of the Milky Way
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作者 GuangChen Sun Yougang Wang +3 位作者 Chao Liu Richard J.Long Xuelei Chen Qi Gao 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2023年第1期127-152,共26页
We combine the kinematics of 159 globular clusters(GCs) provided by the Gaia Early Data Release 3(EDR3) with other observational data to classify the GCs,and to estimate the mass of the Milky Way(MW).We use the agemet... We combine the kinematics of 159 globular clusters(GCs) provided by the Gaia Early Data Release 3(EDR3) with other observational data to classify the GCs,and to estimate the mass of the Milky Way(MW).We use the agemetallicity relation,integrals of motion,action space and the GC orbits to identify the GCs as either formed in situ(Bulge and Disk) or ex situ(via accretion).We find that 45.3% have formed in situ,while 38.4% may be related to known merger events:Gaia-Sausage-Enceladus,the Sagittarius dwarf galaxy,the Helmi streams,the Sequoia galaxy and the Kraken galaxy.We also further identify three new sub-structures associated with the Gaia-Sausage-Enceladus.The remaining 16.3% of GCs are unrelated to the known mergers and thought to be from small accretion events.We select 46 GCs which have radii 8.0 <r<37.3 kpc and obtain the anisotropy parameter β=0.315_(-0.049)^(+0.055),which is lower than the recent result using the sample of GCs in Gaia Data Release 2,but still in agreement with it by considering the error bar.By using the same sample,we obtain the MW mass inside the outermost GC as M(<37.3 kpc)=0.423_(-0.02)^(+0.02)×10^(12)M_(⊙),and the corresponding M_(200)=1.11_(-0.18)^(+0.25)×10^(12)M_(⊙).The estimated mass is consistent with the results in many recent studies.We also find that the estimated β and mass depend on the selected sample of GCs.However,it is difficult to determine whether a GC fully traces the potential of the MW. 展开更多
关键词 GALAXY kinematics and dynamics-Galaxy fundamental parameters-Galaxy halo-(Galaxy:)globular clusters general
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Ground-based and additional science support for SMILE 被引量:2
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作者 J.A.Carter M.Dunlop +46 位作者 C.Forsyth K.Oksavik E.Donovon A.Kavanagh S.E.Milan T.Sergienko R.C.Fear D.G.Sibeck M.Connors T.Yeoman X.Tan M.G.G.T.Taylor K.McWilliams J.Gjerloev R.Barnes D.D.Billet G.Chisham A.Dimmock M.P.Freeman D.-S.Han M.D.Hartinger S.-Y.W.Hsieh Z.-J.Hu M.K.James L.Juusola K.Kauristie E.A.Kronberg M.Lester J.Manuel J.Matzka I.McCrea Y.Miyoshi J.Rae L.Ren F.Sigernes E.Spanswick K.Sterne A.Steuwer T.Sun M.-T.Walach B.Walsh C.Wang J.Weygand J.Wild J.Yan J.Zhang Q.-H.Zhang 《Earth and Planetary Physics》 EI CSCD 2024年第1期275-298,共24页
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
关键词 MAGNETOSPHERE IONOSPHERE magnetosphere-ionosphere coupling ground-based experimentation SMILE CONJUNCTIONS MISSIONS
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Nonstandard Unitary Transformations of Quantum States
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作者 Gombojav O. Ariunbold 《Journal of Applied Mathematics and Physics》 2023年第9期2568-2575,共8页
In quantum optics, unitary transformations of arbitrary states are evaluated by using the Taylor series expansion. However, this traditional approach can become cumbersome for the transformations involving non-commuti... In quantum optics, unitary transformations of arbitrary states are evaluated by using the Taylor series expansion. However, this traditional approach can become cumbersome for the transformations involving non-commuting operators. Addressing this issue, a nonstandard unitary transformation technique is highlighted here with new perspective. In a spirit of “quantum” series expansions, the transition probabilities between initial and final states, such as displaced, squeezed and other nonlinearly transformed coherent states are obtained both numerically and analytically. This paper concludes that, although this technique is novel, its implementations for more extended systems are needed. 展开更多
关键词 Taylor Series Unitary Transformation Temporal Evolution Displaced State Coherent State Squeezed State Two-Mode Squeezed State Holstein-Primakoff State
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Hawking Temperature and the Quantum Pressure of the Schwarzschild Black Hole
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作者 Kapil P. Chandra 《Journal of High Energy Physics, Gravitation and Cosmology》 CAS 2023年第2期515-518,共4页
There is no term for pressure ( P∇V) in the first law of black hole thermodynamics. To address this question, we study the first law of black hole thermodynamics and derive an expression for it. We report that this pr... There is no term for pressure ( P∇V) in the first law of black hole thermodynamics. To address this question, we study the first law of black hole thermodynamics and derive an expression for it. We report that this pressure corresponds to the Hawking temperature and is inversely proportional to the quartic of the Schwarzschild radius. It implies that a lighter and smaller black hole exerts more pressure on its surrounding environment. It might shed light on the other thermodynamic aspects of the black hole. 展开更多
关键词 Hawking Temperature Black Hole Thermodynamics Black Holes
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Machine learning in metal-ion battery research: Advancing material prediction, characterization, and status evaluation
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作者 Tong Yu Chunyang Wang +1 位作者 Huicong Yang Feng Li 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第3期191-204,I0006,共15页
Metal-ion batteries(MIBs),including alkali metal-ion(Li^(+),Na^(+),and K^(3)),multi-valent metal-ion(Zn^(2+),Mg^(2+),and Al^(3+)),metal-air,and metal-sulfur batteries,play an indispensable role in electrochemical ener... Metal-ion batteries(MIBs),including alkali metal-ion(Li^(+),Na^(+),and K^(3)),multi-valent metal-ion(Zn^(2+),Mg^(2+),and Al^(3+)),metal-air,and metal-sulfur batteries,play an indispensable role in electrochemical energy storage.However,the performance of MIBs is significantly influenced by numerous variables,resulting in multi-dimensional and long-term challenges in the field of battery research and performance enhancement.Machine learning(ML),with its capability to solve intricate tasks and perform robust data processing,is now catalyzing a revolutionary transformation in the development of MIB materials and devices.In this review,we summarize the utilization of ML algorithms that have expedited research on MIBs over the past five years.We present an extensive overview of existing algorithms,elucidating their details,advantages,and limitations in various applications,which encompass electrode screening,material property prediction,electrolyte formulation design,electrode material characterization,manufacturing parameter optimization,and real-time battery status monitoring.Finally,we propose potential solutions and future directions for the application of ML in advancing MIB development. 展开更多
关键词 Metal-ion battery Machine learning Electrode materials CHARACTERIZATION Status evaluation
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