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Theoretical Study on Equation of state of Porous Mo and Sn

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Chinese Physics Letters 2014年第1期31卷 132-135页

作者：宋海峰田明锋刘海风宋红州张弓木 Data Center for High Energy Density Physics Institute of Applied Physics and Computational Mathematics Beijing 100088

We present a first-principles scheme to investigate the equation of state （EOS） of porous materials, based on our recently developed modified mean-field potential approach. By taking the effect of the structural parameters on the free energy into account, we calculate the total energy of materials with initial different densities and then study the EOS of porous Mo and Sn as a prototype. The calculated results are in good agreement with the experimental data available, which demonstrates that our scheme is suitable for investigating EOS of porous materials over a wide r^nge of porosities and pressures.

关键词： equations of state

Isospin Effect on Nuclear Stopping in Intermediate Energy Heavy Ion Collisions

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Chinese Physics Letters 2002年第3期19卷 321-323页

作者：李庆峰李祝霞 ChinaInstituteofAtomicEnergy P.O.Box275(18)Beijing102413

By using the isospin-dependent quantum molecular dynamics model, we study the dependence of nuclear stopping QZZ/A and R in intermediate energy heavy ion collisions on system size, initial N/Z, isospin symmetry potential and the medium correction of two-body cross sections. We find the effect of the initial N/Z ratio and isospin symmetry potential on stopping is weak. The excitation function of QZZ/A and R depends on the form of medium correction of two-body cross sections, the equation of state of nuclear matter. Our results show that the behaviour of the excitation function of QZZ/A and R can provide clearer information of the isospin dependence of the medium correction of two-body cross sections.

关键词： equations of state

High-power diode-pumped Yb-doped fiber laser at 1150 nm

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Chinese Optics Letters 2014年第9期12卷 45-48页

作者：苗宇张汉伟肖虎周朴 College of OptoElectric Science and Engineering National University of Defense Technology

A model of steady-state rate equations including amplified spontaneous emission for long-wavelength Yb doped fiber laser is set up, which provides design principle for a practical laser system. We demonstrate a diode-... 详细信息

关键词： equations of state Fiber lasers Fibers Optically pumped lasers Ytterbium

Influence of Different Y-Y Interactions on the Stability of Strange Hadronic Matter

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Chinese Physics Letters 2004年第8期21卷 1483-1486页

作者：宋宏秋苏汝铿钱伟良 ShanghaiInstituteofAppliedPhysics ChineseAcademyofSciencesPOBox800-204Shanghai201800 CCAST(WorldLaboratory) POBox8730Beijing100080 DepartmentofPhysics FudanUniversityShanghai200433

An effective model is used to study the equation of state (EOS) of strange hadronic matter with nucleons, Λ-hyperons and Ξ-hyperons. In the calculation, a newest weak hyperon–hyperon (Y–Y) interaction deduced from the recent observation [Phys. Rev. Lett. 87(2001)212502-1] of a ΛΛ6He double hypernucleus is adopted. The calculated results are compared to those calculated with the strong Y–Y interaction used in previous studies.

关键词： equations of state

Violation of the Weak Energy Condition by the Inflationary Yang—Mills Condensate

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Chinese Physics Letters 2002年第10期19卷 1569-1572页

作者：张杨 AstrophysicsCenter UniversityofScienceandTechnologyofChinaHefei230026NationalAstronomyObservatoryofC

Recent cosmic microwave background data favours a blueshifted primeval perturbation spectrum with an index n>1, which implies that the equation of state of dominant matter should be such that ρ + p < 0 during the inf... 详细信息

关键词： equations of state

Exact Solution for Equilibrium Configurations of Two-Component Plasma Confined between Parallel Plates

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Journal of Applied Mathematics and Physics 2022年第10期10卷 2883-2894页

作者： Michael Grinfeld Pavel Grinfeld The U.S. Army Research Laboratory WMRD Aberdeen Proving Ground USA Department of Mathematics Drexel University Philadelphia USA

It is the fifth part of the study published under the common umbrella of “The Gibbs Variational Method in Thermodynamics of Equilibrium Plasma”. In Parts 1 - 4, we formulated a novel approach to thermodynamics of one- and two-component heterogeneous systems completely or partially filled with a liquid substance in the plasma state. The approach is based on the use of Gibbs variational principles, and it enables efforts to address a variety of problems relating to the equilibrium and stability of such systems. In this fifth part, the results of Parts 1 - 4 are applied to the analysis of equilibrium configurations of a two-component charged plasma trapped between two parallel plates (the geometry often used in various applications).

关键词： Plasma Thermodynamics Gibbs Variational Principles Plasma Stability equations of state

Influences of the bag constant on properties of hybrid stars

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Chinese Physics C 2011年第6期35卷 539-542页

作者：包特木尔巴根李根全王宗昌杨兴强刘广洲 College of Physics and Electronic Engineering Nanyang Normal University College of Physics Jilin University

Influences of the bag constant on the properties of hybrid stars are investigated by using relativistic mean field theory and the MIT bag model to describe the hadron phase and quark phase in the interior of neutron stars, respectively. Our results indicate that the onset of hadron-quark phase transition is put off and the appearance of hyperon species is increased with the increase in bag constant. As a result, the hybrid star equation of state for a mixed phase range stiffens whereas that of the quark phase range softens, and the gravitational mass as well as the corresponding radius of hybrid stars are increased obviously. The gravitational mass of a hybrid star is increased from 1.42 M （M is solar mass） to 1.63M and the corresponding radius is changed from 9.1 km to 12.2 km when the bag constant （B1/4） is increased from 170 MeV to 200 MeV. It is interesting to find that hybrid star equations of state become non-smooth when the TM2 parameter sets in the framework of relativistic mean field theory used to describe the hadronic matter, and consequently, the third family of compact stars appear in the mass-radius relations of hybrid stars in the narrow scope of the bag constant from 175 MeV to 180 MeV. These show that the choice of the bag constant in the MIT bag model has significant influence on the properties of hybrid stars.

关键词： hybrid stars bag constant equations of state mass-radius relations

Properties of hybrid stars in an extended MIT bag model

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Chinese Physics C 2009年第5期33卷 340-344页

作者：包特木尔巴根刘广洲朱明枫 College of Physics and Electronic Engineering Nanyang Normal University College of Physics Jilin University

The properties of hybrid stars are investigated in the framework of the relativistic mean field theory （RMFT） and an MIT bag model with density-dependent bag constant to describe the hadron phase （HP） and quark phase （QP）, respectively. We find that the density-dependent B（p） decreases with baryon density p; this decrement makes the strange quark matter become more energetically favorable than ever, which makes the threshold densities of the hadron-quark phase transition lower than those of the original bag constant case. In this case, the hyperon degrees of freedom can not be considered. As a result, the equations of state of a star in the mixed phase （MP） become softer whereas those in the QP become stiffer, and the radii of the star obviously decrease. This indicates that the extended MIT bag model is more suitable to describe hybrid stars with small radii.

关键词： hybrid stars density-dependent bag constant equations of state mass-radios relations

First-principles study on the electronic,elastic and thermodynamic properties of three novel germanium nitrides

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Journal of Semiconductors 2016年第7期37卷 17-23页

作者：仓玉萍姚晓玲陈东杨帆杨慧明 College of Physics and Electronic Engineering Xinyang Normal UniversityXinyang 464000China School of Architecture and Civil Engineering Xinyang Vocational and Technical CollegeXinyang 464000China

The ultrasoft pseudo-potential plane wave method combined with the quasi-harmonic approach have been used to study the electronic, elastic and thermodynamic properties of the tetragonal, monoclinic and or- thorhombic Ge3N4. The negative formation enthalpies, the satisfactory of Born＇s criteria and the linear variations of elastic constants with pressure indicate that the three polymorphs can retain their stabilities in the pressure range of 0-25 GPa. The three GeaN4 are brittle solids at 0 GPa, while they behave in ductile manners in the pressure range of 5-25 GPa. t- and o-GeaN4 are hard materials but anisotropic, m-Ge3N4 has the largest ductility among the three phases. The results reveal that m-Ge3N4 belongs to an indirect band gap semiconductor, while t- and o-Ge3N4 have direct band gaps. For the thermal properties, several interesting features can be observed above 300 K. o-GeaN4 exhibits the largest heat capacity, while m-Ge3N4 shows the highest Debye temperature. The results predicted in this work can provide reference data for future experiments.

关键词： density functional theory elastic moduli heat capacity equations of state