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An ionic liquid-assisted strategy for enhanced anticorrosion of low-energy PEO coatings on magnesium–lithium alloy

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Journal of Magnesium and Alloys 2024年第6期12卷 2380-2396页

作者： You Zhang Chuping Chen Haoyue Tian Shuqi Wang Chen Wen Fei Chen College of New Materials and Chemical Engineering Hydrogen Energy Research CentreBeijing Institute of Petrochemical TechnologyBeijing 102617China Key laboratory of Advanced Structure-Function Integrated Materials and Green Manufacturing Technology Harbin Institute of TechnologyHarbin 150001China Beijing spacecrafts China Academy of Space TechnologyBeijing 100190China

A low-energy plasma electrolytic oxidation(LePEO)technique is developed to simultaneously improve energy efficiency and *** liquids(1-butyl-3-methylimidazole tetrafluoroborate(BmimBF_(4)))as sustainable corrosion inhibitors are chosen to investigate the corrosion inhibition behavior of ionic liquid(ILs)during the LePEO process for LA91 magnesium-lithium(Mg-Li)*** show that the ionic liquid BmimBF_(4)participates in the LePEO coating formation process,causing an increment in coating thickness and surface *** low conductivity of the ionic liquid is responsible for the voltage and breakdown voltage increases during the LePEO with IL process(LePEO-IL).After adding BmimBF_(4),corrosion current density decreases from 1.159×10^(−4)A·cm^(−2)to 8.143×10^(−6)A·cm^(−2).The impedance modulus increases to 1.048×10^(4)·cm^(−2)and neutral salt spray remains intact for 24 *** superior corrosion resistance of the LePEO coating assisted by ionic liquid could be mainly attributed to its compact and thick barrier layer and physical absorption of ionic *** ionic liquid-assisted LePEO technique provides a promising approach to reducing energy consumption and improving film performance.

关键词： Magnesium-lithium alloy Plasma electrolytic oxidation Low energy Ionic liquid Corrosion resistance

Evidence of guide field magnetic reconnection in flapping current sheets

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Earth and Planetary Physics 2024年第4期8卷 650-658页

作者： YunTian Hou SuPing Duan Lei Dai Chi Wang State Key laboratory of space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China Key laboratory of Solar Activity and space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China

Based on current sheet flapping motion on 27 August 2018 in the dusk flank magnetotail,as recorded by instruments aboard Magnetospheric Multiscale(MMS)spacecraft,we present the first study of guide field reconnection observed in the flux rope embedded in kink-like flapping current sheets near the dusk-side flank of the *** more common magnetotail reconnections,which are symmetric,these asymmetric small-scale(λ_(i)~650 km)reconnections were found in the highly twisted current sheet when the direction normal to the sheet changes from the Z direction into the Y *** unique feature of this unusual reconnection is that the reconnection jets are along the Z direction-different from outflow in the X direction,which is the more usual *** vertical reconnection jet is parallel or antiparallel to the up-and-down motion of the tail’s current *** normalized reconnection rate R is estimated to be~*** results indicate that such asymmetric reconnections can significantly enlarge current sheet flapping,with large oscillation *** letter presents direct evidence of guide field reconnection in a highly twisted current sheet,characterized by enlarged current sheet flapping as a consequence of the reconnection outflow.

关键词： magnetic reconnection magnetotail current sheet

Study on the Performance of the GRANDProto300 Particle Detector Array by Simulation

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research in Astronomy and Astrophysics 2024年第1期24卷 173-177页

作者： Fu-Lin Dai Quan-Bu Gou Xiaoyuan Huang Yi-Qing Guo Key laboratory of Dark Matter and space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210023China School of Astronomy and space Science University of Science and Technology of ChinaHefei 230026China Key laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China University of Chinese Academy of Sciences Beijing 100049China

The Giant Radio Array for Neutrino Detection(GRAND)is a proposed large-scale observatory designed to detect cosmic rays,gamma-rays,and neutrinos with energies exceeding 100 Pe *** GRANDProto300 experiment is proposed as the early stage of the GRAND project,consisting of a hybrid array of radio antennas and scintillator *** latter,as a mature and traditional detector,is used to cross-check the nature of the candidate events selected from radio *** this study,we developed a simulation software called G4GRANDProto300,based on the Geant4 software package,to optimize the spacing of the scintillator detector array and to investigate its effective *** analysis was conducted at various zenith angles under different detector spacings,including 300,500,600,700,and 900 *** results indicate that,for large zenith angles used to search for cosmic-ray in the GRAND project,the optimized effective area is with a detector spacing of 500 *** G4GRANDProto300 software that we developed could be used to further optimize the layout of the particle detector array in future work.

关键词： astroparticle physics instrumentation:detectors (ISM:)cosmic rays

Investigations of nuclear chirality at iThemba LABS

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Frontiers of physics 2024年第2期19卷 7-38页

作者： R.A.Bark E.A.Lawrie C.Liu S.Y.Wang iThemba laboratory for Accelerator Based Sciences National Research FoundationP.O.Box 722Somerset-West 7129South Africa Department of Physics University of the Western CapePrivate Bag X177535BellvilleSouth Africa Shandong Provincial Key laboratory of Optical Astronomy and Solar-Terrestrial Environment Institute of Space SciencesShandong UniversityWeihai 264209China

Progress in the studies of chirality in atomic nuclei at iThemba LABS is *** regions of chirality,around mass 80 and 190 have been discovered using the AFRODITE array,specifically in the nuclei^(74)As,^(78,80,82)Br,^(81)Kr,and^(193,194,198)*** phenomena have been observed,including multiple chiral bands in the same nucleus,the coexistence of octupole correlations and nuclear chirality,and the coexistence of pseudo spin and nuclear *** best example of chiral degeneracy to date was found in ^(194)*** level scheme of ^(106)Ag has been revisited and interpreted in terms of two-and four-quasiparticle *** using the particle-rotor model have shown that the fingerprints of chirality in the two-quasiparticle system only can occur in an idealised model *** systems with a higher number of quasiparticles,the calculations showed that nuclear chirality can persist.

关键词： chirality high-spin states particle-rotor model

Thiamine-modified metabolic reprogramming of human pluripotent stem cell-derived cardiomyocyte under space microgravity

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Signal Transduction and Targeted Therapy 2024年第5期9卷 2132-2142页

作者： Xinglong Han Lina Qu Miao Yu Lingqun Ye Liujia Shi Guangfu Ye Jingsi Yang Yaning Wang Hao Fan Yong Wang Yingjun Tan Chunyan Wang Qi Li Wei Lei Jianghai Chen Zhaoxia Liu Zhenya Shen Yinghui Li Shijun Hu Department of Cardiovascular Surgery of the First Affiliated Hospital&Institute for Cardiovascular Science State Key Laboratory of Radiation Medicine and ProtectionSuzhou Medical CollegeSoochow UniversitySuzhouChina State Key laboratory of space Medicine China Astronaut Research and Training CenterBeijingChina Department of Hand Surgery Union HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina

During spaceflight,the cardiovascular system undergoes remarkable adaptation to microgravity and faces the risk of cardiac ***,the effects and mechanisms of microgravity on cardiac morphology,physiology,metabolism,and cellular biology need to be further *** China started constructing the China space Station(CSS)in 2021,we have taken advantage of the Shenzhou-13 capsule to send human pluripotent stem cell-derived cardiomyocytes(hPSC-CMs)to the Tianhe core module of the *** this study,hPSC-CMs subjected to space microgravity showed decreased beating rate and abnormal intracellular calcium *** and transcriptomic analyses revealed a battery of metabolic remodeling of hPSC-CMs in spaceflight,especially thiamine *** microgravity condition blocked the thiamine intake in *** decline of thiamine utilization under microgravity or by its antagonistic analog amprolium affected the process of the tricarboxylic acid *** decreased ATP production,which led to cytoskeletal remodeling and calcium homeostasis imbalance in *** importantly,in vitro and in vivo studies suggest that thiamine supplementation could reverse the adaptive changes induced by simulated *** study represents the first astrobiological study on the China space Station and lays a solid foundation for further aerospace biomedical *** data indicate that intervention of thiamine-modified metabolic reprogramming in human cardiomyocytes during spaceflight might be a feasible countermeasure against microgravity.

关键词： programming battery modified

The anisotropy of suprathermal electrons in the Martian ionosphere

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Earth and Planetary Physics 2024年第3期8卷 459-471页

作者： YuTian Cao Jun Cui XiaoShu Wu WenJun Liang RuiQi Fu HaoYu Lu Planetary Environmental and Astrobiological research laboratory(PEARL) School of Atmospheric SciencesSun Yat-sen UniversityZhuhai 519082China Key laboratory of Geospace Environment University of Science&Technology of ChinaChinese Academy of SciencesHefei 230026China Center for Excellence in Comparative Planetology Chinese Academy of SciencesHefei 230026China School of space and Environment Beihang UniversityBeijing 102206China

Suprathermal electrons are an important population of the Martian ionosphere, either produced by photoionization of atmospheric neutrals or supplied from the Solar Wind (SW). This study is dedicated to an in-depth investigation of the pitch angle distribution of suprathermal electrons at two representative energies, 19−55 eV and 124−356 eV, using the extensive measurements made by the Solar Wind Electron Analyzer on board the Mars Atmosphere and Volatile Evolution. Throughout the study, we focus on the overall degree of anisotropy, defined as the standard deviation of suprathermal electron intensity among different directions which is normalized by the mean omni-directional intensity. The available data reveal the following characteristics: (1) In general, low energy electrons are more isotropic than high energy electrons, and dayside electrons are more isotropic than nightside electrons;(2) On the dayside, the anisotropy increases with increasing altitude at low energies but remains roughly constant at high energies, whereas on the nightside, the anisotropy decreases with increasing altitude at all energies;(3) Electrons tend to be more isotropic in strongly magnetized regions than in weakly magnetized regions, especially on the nightside. These observations indicate that the anisotropy is a useful diagnostic of suprathermal electron transport, for which the conversion between the parallel and perpendicular momenta as required by the conservation of the first adiabatic invariant, along with the atmospheric absorption at low altitudes, are two crucial factors modulating the observed variation of the anisotropy. Our analysis also highlights the different roles on the observed anisotropy exerted by suprathermal electrons of different origins.

关键词： Mars ionosphere suprathermal electron pitch angle distribution

Optical system for extremely large spectroscopic survey telescope

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Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 158-174页

作者： Ding-qiang Su Hua Bai Xiangyan Yuan Xiangqun Cui Key laboratory of the Ministry of Education School of Astronomy and Space ScienceNanjing UniversityNanjing 210023China Nanjing Institute of Astronomical Optics and Technology(NIAOT) Chinese Academy of SciencesNanjing 210042China University of Chinese Academy of Sciences Nanjing 211135China School of Astronomy and space Science University of Chinese Academy of SciencesBeijing 101408China

This article presents research work on a spectroscopic survey *** idea is as follows:for such a telescope,a pure reflecting optical system is designed,which should have an aperture and a field of view(FOV)both as large as possible and excellent image quality,and then a strip lensm(lens-prism)atmospheric dispersion corrector(S-ADC)is added,only for correcting the atmospheric *** the fund limitation and the simplicity of scaling up,some 12-m telescopes are designed as ***,Korsch,and Meinel put forward the four-mirror Nasmyth systems I and II,which are used in this *** of 1.5°,2°,and 2.5°are *** all systems,the image qualities are *** the S-ADC relaxes the optical glass size restriction,this 12-m telescope with a FOV of 2.5°can be magnified in proportion to a 16-m *** etendue(from Frenchétendue)and focal surface will now be the largest in the *** such a telescope,a pure reflecting optical system can also be obtained.A subsequent coudésystem is designed with excellent image quality.

关键词： telescopes spectroscopic survey

V0405 Dra:A New Deep and Low Mass Ratio Contact Binary with Extremely Fast Decrease in the Orbital Period

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research in Astronomy and Astrophysics 2024年第6期24卷 287-293页

作者： Chao-Yue Li Lin-Qiao Jiang Jie Zheng Yi-Man Liu Xiao-Yu Long Min Sun Han-Lu Zhang Xiao-Man Tian School of Science Leshan Normal UniversityLeshan 614000China Center for Applied Optics research Leshan Normal UniversityLeshan 614000China Key laboratory of Detection and Application of space Effect in Southwest Sichuan Leshan 614000China CAS Key laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China School of Aeronautics Shandong Jiaotong UniversityJinan 250000China

V0405 Dra is a W UMa-type binary *** on the TESS data,we have conducted an orbital period study and performed a light curve analysis for the *** orbital period study reveals that the O-C curve for V0405 Dra exhibits secular decrease at an extremely high rate of d P/dt=-2.71×10^(-6)day year^(-1),along with periodic variations characterized by an amplitude of A_(3)=0.0032 day and a period of P_(3)=1.413 *** orbital periodic change is possibly due to the light-travel time effect resulting from an additional third body in the system,for which we estimate a minimum mass of M_(3)=0.77M_(⊙).By employing the 2013 version of the Wilson-Devinney(W-D)method to synthesize a light curve,we derived photometric solutions indicating that V0405 Dra is a new deep(f=68.7%)and low-mass ratio(q=0.175)contact *** fast decrease in its orbital period is likely caused by mass transfer from the more massive primary star to the less massive secondary star,or due to angular momentum *** further mass transfer and loss of angular momentum,the binary will gradually evolve into a tighter contact configuration,eventually leading to a merger into a single star,following the evolutionary paths suggested for such deep and low mass ratio contact binaries.

关键词： (stars:)binaries(including multiple):close (stars:)binaries:eclipsing stars:individual(V0405 Dra)

Assessment of corrected time-step method for nominal ionospheric gradient calculation: A comparative analysis with spatial approaches

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Earth and Planetary Physics 2024年第4期8卷 641-649页

作者： Slamet Supriadi Prayitno Abadi Susumu Saito Harry Bangkit Dwiko Unggul Prabowo Adi Purwono Ginaldi Ari Nugroho research Center for Smart Mechatronics National Research and Innovation Agency(BRIN)BandungIndonesia research Center for Climate and Atmosphere BRINBandungIndonesia School of Electrical Engineering Telkom UniversityKab.BandungIndonesia Electronic Navigation research Institute National Institute of MaritimePort and Aviation TechnologyTokyoJapan research Center for space BRINBandungIndonesia

The effect of ionospheric delay on the ground-based augmentation system under normal conditions can be mitigated by determining the value of the nominal ionospheric gradient(σvig).The nominal ionospheric gradient is generally obtained from Continuously Operating Reference Stations data by using the spatial single-difference method(mixed-pair,station-pair,or satellite-pair)or the temporal single-difference method(time-step).The time-step method uses only a single receiver,but it still contains ionospheric temporal *** introduce a corrected time-step method using a fixed-ionospheric pierce point from the geostationary equatorial orbit satellite and test it through simulations based on the global ionospheric *** also investigate the effect of satellite paths on the corrected time-step method in the region of the equator,which tends to be in a more north–south direction and to have less coverage for the east–west ionospheric *** study also addresses the limitations of temporal variation correction coverage and recommends using only the correction from *** processes are developed under simulations because observational data are still difficult to *** findings demonstrate that the corrected time-step method yieldsσvig values consistent with other approaches.

关键词： ground-based augmentation system nominal ionospheric gradient time-step correction global ionospheric model