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Early Phases of Star Formation: test.ng chemical tools

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Research in Astronomy and Astrophysics 2024年第1期24卷 96-118页

作者： n.c.Mart.nez S.Paron cOnIcEt-Universidad de Buenos Aires.Instituto de Astronomía y Física del Espacio Ciudad Universitaria(C1428EGA)Ciudad Autónoma de Buenos AiresArgentina

Star-forming processes strongly influence the ISM ***,many high-quality databases are available at millimeter *** them,it is possible to carry out studies that review and deepen previous *** these studies involve large samples of sources,it is preferred to use direct tools to study the molecular *** the aim of test.ng these tools such as the use of the Hcn/Hnc ratio as a thermometer,and the use of H^(13)cO^(+),Hc_(3)n,n_(2)H^(+) and c_(2)H as "chemical clocks," we present a molecular line study toward 55 sources represent.ng massive young stellar objects at different evolutionary stages:infrared dark clouds(IRDcs),highmass protostellar objects(HMPOs),hot molecular cores(HMcs) and ultracompact H II *** found that the use of the Hcn/Hnc ratio as a universal thermometer in the ISM should be taken with care because the Hcn optical depth is a big issue that can affect the ***,this tool should be utilized only after a careful analysis of the Hcn spectrum,checking that.no line,neither the main nor the hyperfine ones,presents absorption *** point out that the analysis of the emission of H^(13)cO^(+),Hc_(3)n,n_(2)H^(+) and c_(2)H could be useful to trace and dist.nguish regions among IRDcs,HMPOs and *** molecular line widths of these four species increase from the IRDc to the HMc stage,which can be a consequence of the gas dynamics related to the starforming processes taking place in the molecular *** results not only contribute with more statistics,act.ng as a probe of such chemical tools,useful to obtain information in large samples of sources,but also complement previous works through the analysis of other types of sources.

关键词： stars:formation ISM:molecules ISM:clouds

Imprints of a gravitational wave through the weak field deflection of phot.ns

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chinese Physics c 2024年第8期48卷 240-245页

作者： Reggie c.Pantig Ali Övgün Physics Department Mapúa University658 Muralla St.IntramurosManila 1002Philippines Physics Department Eastern Mediterranean UniversityFamagusta99628 North Cyprusvia Mersin 10Turkiye

In this study,we investigate the novel phenomenon of gravitational lensing experienced by gravitational waves traveling past a Schwarzschild black hole perturbed by a specific,first-order,polar gravitational *** apply the Gauss-Bonnet theorem,finding a topological contribution to the deflection of light rays passing near the black *** demonstrate that the deflection angle can be determined by analyzing a region entirely outside the path of the light ray,leading to a calculation based solely on the parameters of the perturbing wave(Legendre polynomial order,l;frequency,σ).this approach offers a unique perspective on gravitational lensing and expands our underst.nding of black hole interactions with gravitational waves.

关键词： supermassive black holes gravitational waves chaos weak deflection angle Gauss-Bonnet theorem

Effects of layer interactions on inst.nt.neous stability of finite Stokes flows

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Applied Mathematics and Mechanics(english Edition) 2024年第1期45卷 69-84页

作者： c.en ZHAO Zhenli c.en c.t.MUtASA Dong LI School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China

the stability analysis of a finite Stokes layer is of practical import.nce in flow control. In the present work, the inst.nt.neous stability of a finite Stokes layer with layer interactions is studied via a linear stability analysis of the frozen phases of the base flow. the oscillations of two plates can have different velocity amplitudes, initial phases, and frequencies. the effects of the Stokes-layer interactions on the stability when two plates oscillate synchronously are analyzed. the growth rates of two most unstable modes when δ t equal, and δ = δ*/h*, where δ*and h*are the Stokes-layer thickness and the half height of the channel, respectively. However, their vorticities are different. the vorticity of the most unstable mode is symmetric, while the other is asymmetric. the Stokes-layer interactions have a destabilizing effect on the most unstable mode when δ nd have a stabilizing effect when δ > 0.68. However, the interactions always have a stabilizing effect on the other unstable mode. It is explained that one of the two unstable modes has much higher dissipation than the other one when the Stokes-layer interactions are strong. We also find that the stability of the Stokes layer is closely related to the inflectional points of the base-flow velocity profile. the effects of inconsist.nt velocity-amplitude, initial phase, and frequency of the oscillations on the stability are analyzed. the energy of the most unstable eigenvector is mainly distributed near the plate of higher velocity amplitude or higher oscillation frequency. the effects of the initial phase difference are complicated because the base-flow velocity is extremely sensitive to the initial phase.

关键词： finite Stokes layer inst.nt.neous stability Stokes-layer interaction asynchronous oscillation

HI in High Gas-phase Metallicity Dwarf Galaxy WISEA J230615.06+143927.9

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Research in Astronomy and Astrophysics 2024年第1期24卷 292-299页

作者： Yan Guo c.Sengupta t.c.Scott P.Lagos Y.Luo Purple Mountain Observatory Chinese Academy of SciencesNanjing 210023China School of Astronomy and Space Sc.ences University of Science and Technology of ChinaHefei 230026China Institute of Astrophysics and Space Sc.ences(IA Porto) Rua das Estrelas4150-762PortoPortugal

We present resolved Giant Metrewave Radio telescope H I observations of the high gas-phase metallicity dwarf galaxy WISEA J230615.06+143927.9(z = 0.005)(hereafter J2306) and investigate whether it could be a tidal Dwarf Galaxy(tDG) candidate. tDGs are observed to have higher metallicities than normal dwarfs. J2306 has an unusual combination of a blue g-r color of 0.23 mag, irregular optical morphology and high-metallicity(12 +log(O/H) = 8.68 ± 0.14), making it an interest.ng galaxy to study in more detail. We find J2306 to be an H I rich galaxy with a large ext.nded, unperturbed rotat.ng H I disk. Using our H I data we estimated its dynamical mass and found the galaxy to be dark matter(DM) dominated within its H I radius. the quantity of DM, inferred from its dynamical mass, appears to rule out J2306 as an evolved tDG. A wide area environment search reveals J2306 to be isolated from any larger galaxies which could have been the source of its high gas metallicity. Additionally, the H I morphology and kinematics of the galaxy show no indication of a recent merger to explain the *** detailed optical spectroscopic observations of J2306 might provide an answer to how a seemingly ordinary irregular dwarf galaxy achieved such a high level of metal enrichment.

关键词： galaxies:abundances galaxies:dwarf galaxies:irregular radio lines:galaxies radio lines:ISM

near resonance vibration isolation on a levered-dual response(LEDAR)coulomb-damped system by differential preloads/offsets in linear springs

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Applied Mathematics and Mechanics(english Edition) 2024年第6期45卷 1033-1050页

作者： t.I.tOLUWALOJU c.K.tHEIn D.HALIM Department of Mechanical Materials and Manufacturing EngineeringUniversity of Nottingham Ningbo ChinaNingbo 315100Zhejiang ProvinceChina nott.ngham ningbo china Beacons of Excellence Research and Innovation Institute University of Nottingham Ningbo ChinaNingbo 315048Zhejiang ProvinceChina

the levered-dual response(LEDAR)coulomb-damped system attains near resonant vibration isolation by differential preloads/offsets in linear *** takes the advantages of both the preloads/offsets in linear springs and the guiderail friction for realizing different levels of vibration *** isolation capacities are investigated on the strategies with both the horizontal and vertical guiderails,with the horizontal rail only,and without *** compressive preloads generally result in the consumption of most of the initial excitation energy so as to overcome the pot.ntial *** isolation onsets at the frequency ratio of 1∓0.095 on the left-hand side(LHS)and the right-hand side(RHS)of the lever are relative to the load plate *** observed near resonant isolation thus makes the LEDAR system a candidate for the isolation of the mechanical systems about resonance while opening a path for simult.neous harvesterisolation functions and passive functions at extreme frequencies.

关键词： lever ratio coulomb damping preload t.nsion/compression isolation band/depth offset pot.ntial

Large dinosaur egg accumulations and their significance for underst.nding nest.ng behaviour

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Geosc.ence Frontiers 2024年第5期15卷 467-488页

作者： L.Ezquerro R.coimbra B.Bauluz c.núñez-Lahuerta t.Román-Berdiel M.Moreno-Azanza Departamento de Geodinámica Estratigrafía y PaleontologíaFacultad de Ciencias GeológicasUniversidad Complutense de MadridC/JoséAntonio Novais1228040MadridSpain Aragosaurus-IUcA:Recursos Geológicos y Paleoambientales.Departamento de c.encias de la tierra.Facultad de c.encias Universidad de ZaragozaC/Pedro Cerbuna 1250009 ZaragozaSpain Museu da Lourinha LourinhaPortugal GeoBiotec Department of Earth SciencesNOVA School of Science and TechnologyUniversidade Nova de LisboaCaparicaPortugal GeoBiotec Departamento de GeocienciasUniversidade de AveiroAveiroPortugal Insitut catalàde Paleoecologia Humana i EvolucióSocial(IPHES-cERcA) Zona Educacional 4Campus Sescelades URV(Edifici W3)43007 TarragonaSpain Departament d´Història i Història de l´Art Universitat Rovira i VirgiliAv.Catalunya 3543002 TarragonaSpain Geotransfer IUcA Departamento de Ciencias de La TierraFacultad de CienciasUniversidad de ZaragozaZaragozaSpain

the accurate identification of dinosaur egg accumulations as nests or clutches is crucial for underst.nding the reproductive behaviour of these ext.nct ***,exist.ng methods oft.n rely on the presence of complete eggs and embryo remains,and sedimentological criteria that are only applicable to well-structured *** this study,we introduce an innovative approach to characterize egg accumulations in structureless sediments,where traditional nest structures may not be *** methodology employs a unique combination of sedimentological,taphonomic,geochemical,and geophysical proxies for the study of egg *** applied this approach to the egg accumulation from Paimogo(Jurassic,Portugal),traditionally interpreted as a *** findings reveal that the Paimogo egg assemblage is a secondary deposit,result.ng from a flooding event in a fluvial plain that dismantled several allosauroid and crocodylomorph *** eggshell vapor conduct.nce results,coupled with sedimentological evidence,suggest that allosauroid dinosaurs buried their eggs in the dry terrain of overbank areas close to a main channel during the breeding season,likely during the dry season to prevent the embryos from *** research underscores the necessity of multidisciplinary approaches in interpret.ng egg accumulations and offers a novel methodology for studying these accumulations in structureless *** findings provide new insights into the breeding behaviour and nest.ng preferences of these ext.nct organisms,contribut.ng to our underst.nding of dinosaur ecology.

关键词： Breeding behaviour theropod taphonomy Stable isotopes Magnetic susceptibility Jurassic

Radiative decays D*(s)→ D(s)γ in covariant confined quark model

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chinese Physics c 2024年第2期48卷 45-56页

作者： c.t.tran M.A.Ivanov P.Santorelli Q.c.Vo Department of Physics HCMC University of Technology and EducationVo Van Ngan 1700000 Ho Chi Minh CityVietnam Bogoliubov Laboratory of theoretical Physics Joint Institute for Nuclear Research141980 DubnaRussia Dipartimento di Fisica"E.Pancini" Universitàdi Napoli Federico ⅡComplesso Universitario di Monte S.AngeloVia CintiaEdificio 680126 NapoliItaly Istituto nazionale di Fisica nucleare Sezione di Napoli80126 NapoliItaly University of Sc.ence 700000 Ho Chi Minh CityVietnam

Radiative decays D((s))*→D((s))γare revisited in light of new experimental data from the BaBar and BESⅢ*** radiative couplings gD*Dγencoding nonperturbative QcD effects are calculated in the framework of the covariant confined quark model developed by *** compare our results with other theoretical studies and experimental *** couplings(in GeV-1)|g(D*+D+γ)|=0.45(9)and|g(D*0D0γ)|=1.72(34)calculated in our model agree with the corresponding experimental data|g(D*+D+γ)|=0.47(7)and|g(D*0D0γ)|=1.77(16).the most interest.ng case is the decay Ds*→Dsγ,for which a recent prediction based on light-cone sum rules at.next-to-leading order|gDs*Dsγ|=0.60(19)deviates from the first(and only to date)lattice QcD result|gDs*Dsγ|=0.11(2)at.nearly3σ.Our calculation yields|gDs*Dsγ|=0.29(6),which falls somehow between the two mentioned results,although it is larger than those predicted in other studies using quark models or QcD sum rules.

关键词： covariant quark model radiative decay charmed meson

Mathematical modeling and simulations of stress mitigation by coat.ng polycrystalline particles in lithium-ion batteries

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Applied Mathematics and Mechanics(english Edition) 2024年第6期45卷 947-962页

作者： n.IQBAL J.cHOI S.F.SHAH c.LEE S.LEE Department of Mechanical Roboticsand Energy EngineeringDongguk University-SeoulSeoul 04620Republic of Korea

A chemo-mechanical model is developed to investigate the effects on the stress development of the coat.ng of polycrystalline ni-rich LinixMnyco_(z)O_(2)(x≥0.8)(nMc)particles with poly(3,4-ethylenedioxythiophene)(PEDOt).the simulation results show that the coat.ng of primary nMc particles significantly reduces the stress generation by effic.ently accommodat.ng the volume change associated with the lithium diffusion,and the coat.ng layer plays roles both as a cushion against the volume change and a channel for the lithium transport,promot.ng the lithium distribution across the secondary particles more ***,the lower stiffness,higher ionic conductivity,and larger thickness of the coat.ng layer improve the stress *** paper provides a mathematical framework for calculat.ng the chemo-mechanical responses of anisotropic electrode materials and fundamental insights into how the coat.ng of nMc active particles mitigates stress levels.

关键词： lithium-ion battery(LIB) polycrystalline particle coat.ng finite element simulation ni-rich LinixMnyco_(z)O_(2)(x>0.8)(nMc)

Decision and coordination of an E-commerce Supply chain considering Returns and network Externalities

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Journal of Systems Sc.ence and Systems engineering 2024年第5期33卷 552-575页

作者： Liang Shen Fei Lin Yuyan Wang Luping Ding t.c.E.c.eng Dexia Wang School of Public Finance and taxation Shandong University of Finance and Economicsjinan 250014China bschool of Management Sc.ence and engineering Shandong University of Finance and EconomicsJinan 250014China PolyU Business School The Hong Kong Polytechnic UniversityHung HomKowloonHong Kong 999077China

considering the large number of returns in online sales and the network externalities of e-platforms,we develop a decentralized model and a centralized model to explore the impacts of returns and network externalities on e-commerce supply chain(EcSc)*** show that in the decentralized model,the service level,price,market demand,and EcSc members’profits increase with the network externality ***,the service level and price increase,while the market demand and EcSc members’profits decrease with the product return *** centralized model is the optimal operat.ng mode when it is properly *** design the“commission and return cost-sharing”contract to optimize EcSc,in which the proportion of the e-platform’s sharing of the return handling cost is exactly equal to the proportion of the system profit after *** on the decentralized model,we develop two ext.nded models in which we endogenize the impacts of the service level and return rate on the network externality *** comparisons between the ext.nded and decentralized models,we show that high-quality service can improve EcSc’s profitability,while a high return rate hurts its economic performance.

关键词： E-commerce supply chain coordination mechanism network externalities return products