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Dynamics of neutrino-driven winds:inclusion of accurate weak interaction rates in strong magnetic fields

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Research in Astronomy and Astrophysics 2013年第2期13卷 207-214页

作者： men-Quan liu Zhong-Xiang Wang Shanghai Astronomical Observatory Chinese Academy of Sciences Institute of Theoretical Physics China West Normal University

Solving Newtonian steady-state wind equations while considering the ac- curate weak interaction rates and magnetic fields （MFs） of young neutron stars, we study the dynamics and nucleosynthesis of neutrino-driven winds （NDWs） from proto neutron stars （PNSs）. For a typical 1.4 Mo PNS model, we find that the nucleosyn- thesis products are closely related to the luminosity of neutrinos and anti-neutrinos. The lower the luminosity is, the larger is the effect on the NDWs caused by weak in- teractions and MFs. At a high anti-neutrino luminosity of typically 8 × 1051 erg s-1, neutrinos and anti-neutrinos dominate the processes in an NDW and the MFs hardly change the wind＇s properties. But at a low anti-neutrino luminosity of 1051 erg s-1 at the late stage of an NDW the mass of the product and process of nucleosynthesis are changed significantly in strong MFs. Therefore, in most of the models considered for the NDWs from PNSs, based on our calculations, the influences of MFs and the net weak interactions on the nucleosynthesis are not significant.

关键词： nuclear reactions, nucleosynthesis, abundances -- hydrodynamics --stars neutrons

A new estimation of manganese distribution for local dwarf spheroidal galaxies

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Research in Astronomy and Astrophysics 2016年第9期16卷 137-144页

作者： men-Quan liu Zhong-Xiang Wang School of Physics and Space Science China West Normal University Shanghai Astronomical Observatory Chinese Academy of Sciences

The distribution of abundance for iron-peak elements in dwarf spheroidal galaxies （dSphs） is important for galaxy evolution and supernova （SN） nucleosynthesis. Nowadays, manganese （Mn） is one of the most observed iron-peak elements in local dSphs. Studies of its distributions allow us to derive and understand the evolution history of these dSphs. We improve a phenomenological model by a two-curve model including a new initial condition, that includes detailed calculations of SN explosion rates and yields. We compare the results with the observed Mn distribution data for three dSphs： Fornax, Sculpture and Sextans. We find that the model can describe the observed Fe and Mn distributions well simultaneously for the three dSphs. The results also indicate that the initial conditions should be determined by the low metallicity sam- ples in the beginning time of the galaxies and the previous assumption of metellicity-dependant Mn yield of SNIa is not needed when a wide mass range of core-collapse SNe is included. Our method is applicable to the chemical evolution of other iron-peak elements in dSphs and can be modified to provide more detailed processes for the evolution of dSphs.

关键词： galaxies dwarf-- galaxies individual (Fornax, Sculptor, Sextans) -- galaxies evolution --supernovae general

Magnetic Field Effect on β^＋ Decay in the Crusts of Accreting Neutron Stars

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Communications in Theoretical Physics 2007年第4期47卷 765-768页

作者： ZHANG Jie liu men-Quan LUO Zhi-Quan Institute of Physics and Electron Information China West Normal University Nanchong 637002 China

Based on shell model of nuclei, the influence of a high magnetic field on β^＋ decay in the crusts of accreting neutron stars is analyzed. The magnetic field effect on 54 Mn is discussed. The results show that a weak magnetic field makes little effect on β^＋ decay but a strong magnetic field （B 〉 10^11 G） improves β^＋ decay rates obviously. The conclusion derived will benefit to develop further research on nuclear astrophysics in the future.

关键词： β^+ decay strong magnetic field neutron star

Collapse Velocity and Prompt Explosion for the Presupernova Model Ws15M_⊙

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Chinese Journal of Astronomy and Astrophysics 2006年第4期6卷 455-460页

作者： Zhi-Quan Luo men-Quan liu Qiu-He Peng Zuo-Heng Xie Institute of Theoretical Physics China West Normal University Nanchong 637002 Department of Physics Sichuan University Chengdu 610065 Department of Astronomy Nanjing University Nanjing 210093 Institute of Applied Mathematics Chinese Academy of Sciences Beijing 100080

For the presupernova modelWs15M⊙, we re-calculate the electron capture （EC） timescale and hydrodynamical （HD） timescale. We found that the EC timescale can be smaller than the HD timescale in the inner region of the collapse iron core at the moment immediately before the shock wave bounce. The change in these two timescales at the late stage of core collapse is expected to affect the collapse velocity. If the late-time collapse velocity is artificially increased by a small quantity, then prompt explosion of the supernova may happen. Further calculations are still needed to check the plausibility of the acceleration mechanism caused by the faster EC process.

关键词： star: supernova-- nuclear reaction -- nucleosynthesis

Equilibrium and mechanism studies of gold(Ⅰ)extraction from alkaline aurocyanide solution by using fluorine-free ionic liquids

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Rare Metals 2021年第7期40卷 1987-1994页

作者： Ya-Ting Wang men liu Nian Tang Sheng-Jian Li Yan Sun Shi-Xiong Wang Xiang-Jun Yang Key Laboratory of Medicinal Chemistry for Natural Resource(Yunnan University) Ministry EducationSchool of Chemical Science and TechnologyYunnan UniversityKunming 650091China

Solvent extraction based on ionic liquids is generally considered to be an environmentally benign and effective technology for gold(Ⅰ)*** aim of this work is to study gold(Ⅰ)extraction from aurocyanide solution using fluorine-free ionic liquids[A336][SCN],[A336][MTBA]and[A336][Mal].Various factors that affect gold(Ⅰ)extraction(including concentration of ionic liquids,equilibrium pH,concentration of the modifier tributyl phosphate(TBP),reaction time and initial concentration of gold in an aqueous solution)were studied and *** results indicate that the three Aliquat336-based ionic liquids all exhibit excellent behaviors for gold(Ⅰ)*** than 99.8%of gold(Ⅰ)can be extracted from the aqueous phase into the ionic liquid *** gold-loaded ionic liquids were characterized using infrared spectroscopy and mass spectrometry to study the extraction mechanism of gold(Ⅰ).The results revealed that extraction of gold(Ⅰ)into the ionic liquid phase was based on an exchange reaction between the anion Au(CN)2-in aqueous solution and the anion SCN-in ionic liquid[A336][SCN].The logarithmic relationship between distribution coefficient and TBP concentration indicates that two TBP molecules are involved in the formation of the extracted *** extracted complex was determined to be A336^(+)·Au(CN)_(2)^(-)·2 *** addition,the gold(Ⅰ)-loaded ionic liquids can be efficiently stripped using NH4 SCN,2-methylthiobenzoic acid and methyl *** results establish that Aliquat 336-based ionic liquids have potential application prospects in gold(Ⅰ)recovery from cyanide solutions.

关键词： Gold(Ⅰ) Solvent extraction Ionic liquid Alkaline aurocyanide solution

Tailoring thermal behavior and luminous performance in LuAG:Ce films via thickness control for high-power laser lighting applications

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Rare Metals 2024年第12期43卷 6537-6548页

作者： Shao-Hong liu Bing-Guo Xue Li-Min Zhou Hao Cui Man-men liu Li Chen Ming Wen Hai-Gang Dong Feng liu Wei Wang Song Li Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education) School of Materials Science and EngineeringNortheastern University State Key Laboratory of Advanced Technologies for Comprehensive Utilization of Platinum Metals Yunnan Precious Metals Laboratory Co.Ltd Sino-Platinum Metals Semiconductor Materials (Yunnan) Co Ltd

Lutetium aluminum garnet doped with cerium（LuAG:Ce） thin films have been identified as a promising material for high-power laser-driven lighting *** this study,spray pyrolysis we employed to fabricate LuAG:Ce films on sapphire substrates and the impact of film thickness on thermal management and light emission efficiency was *** results show that,regardless of thickness,LuAGiCe films exhibit impressive internal quantum efficiencies（IQE） exceeding 83.2% and external quantum efficiencies（EQE） surpassing 56.4%,with minimal alteration of luminescent ***,thinner films facilitate more efficient heat dissipation to the underlying sapphire substrate,resulting in superior thermal management and outstanding luminous performance under high-power laser ***,the thinnest LuAG:Ce film（15.79 μm） exhibited rapid thermal stabilization（～130℃ within 30 s） and maintained stability during continuous irradiation lasting 30 min,with a corresponding decrease in luminous flux to 87.9% of its initial value within the first 60 *** film also demonstrated relatively high and stable conversion efficiency and luminous efficiency,achieving higher saturation thresholds(15 W·mm-2) and luminous flux（1070 lm）.In contrast,thicker films exhibited a shift in the saturation point toward lower power *** findings provide valuable insights for the practical implementation of LuAG:Ce films in advanced lighting technologies.

关键词： Heat dissipation Laser lighting LuAG:Ce Luminescence saturation Phosphor converter

Concurrent toughening and hardening in AgMgNi alloys by internal oxidation

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Rare Metals 2024年第12期43卷 6625-6638页

作者： Bing-Rui liu Hai-Cheng Zhu Shao-Hong liu Li-Min Zhou Hao Cui Man-men liu Li Chen Ming Wen Hai-Gang Dong Feng liu Wei Wang Song Li Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education) School of Materials Science and EngineeringNortheasterm University State Key Laboratory of Advanced Technologies for Comprehensive Utilization of Platinum Metals Yunnan Precious Metals Laboratory Co.Ltd Sino-Platinum Metals Semiconductor Materials (Yunnan) Co. Ltd

Enhancing the ductility of internally oxidized AgMg alloys has posed a longstanding challenge.A new method to achieve simultaneous hardening and toughening of AgMgNi alloys is presented by means of internal *** influence of Ni content on the internal oxidation process and the mechanical behavior of AgMgNi alloys is systematically *** is found that Ni addition induces grain refinement by forming nanoscale Ni particles,which act as heterogeneous nucleation sites and inhibit grain growth during internal *** enhances the plasticity and toughness of the alloys via the Hall-Petch *** alloys exhibit a conductivity of ～42 MS·m-1and surface hardness of ～HV125,which are insensitive to the variation of Ni content within 0 wt%-2 wt%.The optimal range of Ni content for achieving the best combination of hardness,strength and toughness is0.15 wt%-0.3 wt%,corresponding to alloys with a tensile strength above 300 MPa and a toughness surpassing3300 MJ·*** Ni contents reduce the internal oxidation depth（from about 340.6 to about 238.4 μm） and the tensile strength（from about 342.1 to about 230.1 MPa）of the alloys by generating micrometer-sized Ni-rich particles in the matrix,which consume oxygen,obstruct some of the oxygen diffusion channels and impede the oxidation front *** non-oxidized region,which does not benefit from oxidation strengthening,diminishes the overall strength of the *** results reveal the crucial role of Ni in regulating the internal oxidation dynamics and microstructure evolution of AgMgNi alloys,and suggest a novel approach for designing high-performance alloys with concurrent hardening and toughening.

关键词： AgMgNi alloy Grain refinement Hardening Internal oxidation Toughening

Controlled synthesis of monodispersed spherical ruthenium powders

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Rare Metals 2023年第12期42卷 4246-4254页

作者： Feng-Shuo Xu Hao Cui Man-men liu Jia-Lin Chen Ming Wen Chuan-Jun Wang Wei Wang Song Li Xu-Dong Sun Shao-Hong liu Key Laboratory for Anisotropy and Texture of Materials(Ministry of Education) School of Materials Science and EngineeringNortheastern UniversityShenyang 110819China State Key Laboratory of Advanced Technologies for Comprehensive Utilization of Platinum Metals Yunnan Precious Metals Laboratory Co.Ltd.Kunming 650106China

Monodispersed spherical Ru powders are essential for fabricating high-performance Ru sputtering targets,which have applications in very-large-scale integration circuits and magnetic recording ***,the synthesis of such powders remains a major ***,we reported the synthesis of monodispersed spherical Ru powders through controlling the molar ratio of SO_(4)^(2-)to Ru^(3+)in urea homogeneous precipitation solution and the annealing *** the addition of(NH4)2SO_(4)into the reaction solution,only gel-like precipitation particles were *** introducing(NH_(4))_(2)SO_(4) into the reaction solution and controlling the molar ratio of SO_(4)^(2-)to Ru3+between 0.50 and 1.00,monodispersed spherical precursor powders were *** nucleation and growth of monodispersed spherical precursor particles in solution were found to conform to LaMer's *** controlled annealing at 450℃in a hydrogen atmosphere,the obtained metallic Ru powder with an average particle size of 135 nm inherited the spherical morphology and excellent dispersity from the monodispersed spherical precursor *** results and findings would deepen the understanding of the preparation of monodispersed Ru and Ru-like powders.

关键词： Ruthenium Sputtering target Spherical powder Integration circuits Magnetic recording

Microstructure and properties of continuous casting Ag-28Cu-8Sn alloy fabricated by dieless drawing

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Rare Metals 2020年第3期39卷 279-288页

作者： Ji-Heng Fang Ming Xie Ji-Ming Zhang You-Cai Yang Yong-Tai Chen Song Wang Man-men liu Jie-Qiong Hu State Key Laboratory of Advanced Technologies for Comprehensive Utilization of Platinum Metal Kunming650106China

Ag-28Cu-8Sn(wt%)alloy is a widely used brittle silver-based brazing filler *** wire of brazing filler metal was prepared by continuous casting process and dieless drawing *** phase structure was measured by X-ray diffraction(XRD),and the microstructure of wetting interface,cast states,processing states and fracture morphologies were characterized by the optical microscopy(OM)and scanning electron microscopy(SEM),*** electrical conductivity,hardness,tensile strength and elongation rate were tested as ***,the solid-liquid phase temperature was measured by a differential scanning calorimeter(DSC),and the wettability of brazing filler metal was tested by spreading *** outcomes obtained show that the as-cast microstructure is a typical three-zone structure,including region of surface fine grain,zone of columnar grain and region of center equiaxed ***-28Cu-8Sn alloy is mainly composed of Ag-rich a-phase,Cu-rich pphase and intermediate *** refinement appears in the cross section,as for grains of the longitudinal section,the shape is changed from ribbon to fiber to form a silk *** strength and hardness improve with the increase in the true strain,while the conductivity and elongation are ***,the solid-phase temperature is 605.9℃,and the liquid-phase temperature is 725.1℃.The spreading area of Ag-28Cu-8Sn brazing filler metal is 174 mm^2,and the metallurgical bonding occurs between Ag-28Cu-8Sn brazing filler metal and Cu *** addition,compared with cold drawing process,there are not any microcracks at the fracture morphology for the alloy fabricated by dieless *** dieless drawing process overcomes some processing defects of traditional cold drawing,and the processing performance of Ag-28Cu-8Sn alloy is improved.

关键词： Continuous casting Cold drawing Dieless drawing Microstructure Properties