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An Investigation on γ induced activation reactions on human essential elements

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Nuclear Science and Techniques 2015年第3期26卷 86-89页

作者：吕翠娟马春旺刘一璞张文岗左嘉旭 Institute of Particle and Nuclear Physics Henan Normal University College of Physics and Electronic Engineering Henan Normal University Department of Nuclear and Radiation Safety Research Nuclear and Radiation Safety Center (MEP)

In radiotherapy, the energy of the γ rays used could be larger than 10 Me V, which would potentially activate stable nucleus into a radioactive one. The γ induced reactions on some of the human essential elements are studied to show the probability of changes of nuclei. The Talys 1.4 toolkit was adopted as the theoretical model for calculation. The reactions investigated include the(γ, n) and(γ, p) channels for the stable Na, Mg, Cl,K, Ca, and Fe isotopes, with the incident energy of γ ranging from 1 to 30 Me V. It was found that the cross sections for the reactions are very low, and the maximum cross section is no larger than 100 mb. By considering the threshold energy of the channel, the half-life time of the residue nucleus, and the percentage of the element accounting for the weight and its importance in the body, it is suggested to track the radioactive nuclei22 Na,41Ca, and42,43 K after γ therapy. The results might be useful for medical diagnosis and disease treatment.

关键词：活化反应必需元素诱导反应能量范围放射治疗铁同位素阈值能量疾病治疗

Residue Coulomb Interaction Among Isobars and Its Influence in Symmetry Energy of Neutron-Rich Fragment

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Communications in Theoretical Physics 2015年第9期64卷 334-340页

作者：马春旺王闪闪张艳丽赵艺龙魏慧玲 Institute of Particle and Nuclear Physics Henan Normal University Shanghai Institute of Applied Physics Chinese Academy of Sciences College of Physics and Electronic Engineering Henan Normal University

The residue Coulomb interaction(RCI), which affects the result of symmetry-energy coefficient of neutronrich nucleus in isobaric yield ratio(IYR) method, is difficult to be determined. Four RCI approximations are investigated:(i) The M1–RCI adopting the ac/T(the ratio of Coulomb energy coefficient to temperature) determined from the IYR of mirror-nucleus fragments;(ii) The M2–RCI by fitting the difference between IYRs;(iii) The M3–RCI adopting the standard Coulomb energy at a temperature T = 2 Me V; and(iv) Neglecting the RCI among isobars. The M1–, M2– and M3–RCI are no larger than 0.4. In particular, the M2–RCI is very close to zero. The effects of RCI in asym/T of fragment are also studied. The M1– and M4–asym/T are found to be the lower and upper limitations of asym/T, respectively. The M2–asym/T overlaps the M4–asym/T, which indicates that the M2–RCI is negligible in the IYR method, and the RCI among the three isobars can be neglected. The relative consistent low values of M3–asym/T(7.5 ± 2.5) are found in very neutron-rich isobars.

关键词： isobaric yield ratio residue Coulomb interaction s

A nuclear density probe:isobaric yield ratio difference

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Nuclear Science and Techniques 2015年第2期26卷 83-88页

作者：于勉段坤杰王闪闪张艳丽马春旺 Xinxiang Medical university Institute of Particle and Nuclear Physicshenan normal university henan university of Urban Construction Shanghai Institute of Applied PhysicsChinese Academy of Sciences

We report our recent progress on the nuclear symmetry energy probe,which is called the isobaric yield ratio difference(IBD),and its application in neutron density determination in *** results obtained by the IBD,from which the isobaric yields in the measured 140 A MeV ^(40.48)Ca + ~9Be and ^(58.64)Ni + ~9Be reactions,and the calculated 80 A MeV ^(38-52)Ca +^(12)C reactions by using a modified statistical abrasion-ablation model,show the sensitivity of the IBD to the density differences between reactions.

关键词：等压探头屈强比核密度测定实验 IBD 中子密度密度差异

First principle study on the elastic and thermodynamic properties of TiB_2 crystal under high temperature

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Chinese Physics B 2009年第3期18卷 1248-1252页

作者：王春雷余本海霍海亮陈东孙海滨 College of Physics and Electronic Engineering Xinyang Normal University Discipline Inspection Commission Xinyang Normal University

This paper predicts the elastic and thermodynamic characteristics of TiB2 crystal through the method of density functional theory within the generalized gradient approximation （GGA）. The five independent elastic constants （Cij）, the bulk modulus （B0）, the dependence of bulk modulus （B0） on temperature T and pressure P and the coefficient of thermal expansion （αL） at various temperatures have been evaluated and discussed. According to calculation, the bulk modulus will increase with increasing pressure while decrease with the increasing temperature. The coefficient of thermal expansion is consistent with the famous Griineisen＇s law when the temperature is not too high. The obtained results agree well with the experimental and other theoretical results.

关键词： titanium diboride density functional calculations bulk modulus coefficient of heat expansion

First-principle study on the physical properties of ultra-incompressible ReB_2

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Acta Metallurgica Sinica(English Letters) 2009年第4期22卷 284-290页

作者： Chunlei WANG Qiuju SUN Xuanyu SONG Benhai YU College of Physics and Electronic Engineering Xinyang Normal University Xinyang 464000 China

The elastic and physical characteristics of ReB2 crystal have been predicted through a method of density functional theory within the generalized gradient approximation （GGA）. Five independent elastic constants are C11=662 GPa, C12=150 GPa, C13=146 GPa, C33=1090 GPa and Caa=263 GPa. The bulk modulus （B）, shear modulus （G）, young＇s modulus （E）, Poisson＇s ratio （γ） and the ratio of linear com- pressibility coefficient along the a- and c-axis crystal direction （Ka/Kc） are 356 GPa, 305 GPa, 711 GPa, 0.167 and 1.758, respectively. In addition, the dependence of bulk modulus （B） on temperature （T） and pressure （p） as well as the coefficient of thermal expansion （αL） at various temperatures are evaluated and discussed. The coefficient of thermal expansion is consistent with the famous Grüneisen＇s law when the temperature is less than 1500 K. Our results agree well with the other experimental results.

关键词： Rhenium diboride Density functional calculations Bulk modulus Coefficient of thermal expansion

Symmetry energy from neutron-rich fragments in heavy-ion collisions,and its dependence on incident energy,and impact parameters

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Chinese Physics C 2013年第2期37卷 19-25页

作者：马春旺宋恒利普洁张同林张莎王闪闪赵新丽陈丽 Department of Physics Henan Normal University Department of Nuclear Physics Shanghai Institute of Applied Physics

The yields of fragments produced in the ^60Ni＋ ^12C reactions at 80 A and 140 A MeV, and with maximum impact parameters of 1.5, 2 and 7.3 fm at 80 A MeV are calculated by the statistical abrasion-ablation model. The yields of fragments are analyzed by the isobaric yield ratio （IYR） method to extract the coefficient of symmetry energy to temperature （asym/T ）. The incident energy is found to influence asym/T very little. It’s found that asym/T of fragments with the same neutron-excess I = N-Z increases when A increases, while asym/T of isobars decreases when A increases. The asym/T of prefragments is rather smaller than that of the final fragments, and the asym/T of fragments in small impact parameters is smaller than that of the larger impact parameters, which both indicate that asym/T decreases when the temperature increases. The choice of the reference IYRs is found to have influence on the extracted a sym /T of fragments, especially on the results of the more neutron-rich fragments. The surface-symmetry energy coefficient （bs/T ） and the volume-symmetry energy coefficient （bv/T） are also extracted, and the bs/bv is found to coincide with the theoretical results.

关键词： symmetry energy isobaric yield ratio neutron-rich nucleus heavy-ion collisions

Investigation of neutron induced reactions on ^(23)Na by using Talys 1.4

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Chinese Physics C 2014年第10期38卷 15-17页

作者：马春旺景瑞轶冯晓曹喜光吕翠娟王宏伟 Institute of Particle and Nuclear Physics Henan Normal University Department of Nuclear Physics Shanghai Institute of Applied PhysicsChinese Academy of Sciences

The neutron induced reactions on ^23Na are investigated by using the Talys1.4 program. The calculated results for the ^23Na（n, 2n）22Na reaction are found to agree with the experimental results. The cross sections of the residues of the（n, n）,（n, γ）,（n, p）, and（n, np） channels in the reactions are presented, and at the same time, the neutron induced reactions on22 Ne are also investigated.

关键词： neutron activation, ^23Na(n 2n)^22Na, ^23Na(n np)^22Ne, ^22Ne(n x)

Phase Transition Characters and Thermodynamics Modeling of the Newly-Discovered wⅡ- and Post-Spinel Si_3N_4 Polymorphs: A First-Principles Investigation

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Acta Metallurgica Sinica(English Letters) 2013年第2期26卷 131-136页

作者： Benhai YU Dong CHEN College of Physics and Electronic Engineering Xinyang Normal University

The equilibrium lattice constants, elastic constants and elastic moduli of wll- and post-spinel Si3Na have been investigated in the pressure ranges of 0-40 GPa and 160-240 GPa, respectively. These two phases are found to be dynamically stable. The post-spinel phase is one of the strongest materials yet investigated under extreme compressions. Some fundamental properties and phase transition characters are evaluated from the quasi-harmonic approximation. The transition pressures from the γ phase to the post-spinel phase are 152.5 GPa （at 300 K） and 181.8 GPa （at 1500 K）. The phase transition pressures of theβ→wll and γ→postspinel transitions increase with the rise of temperature; hence, at higher temperature it requires higher pressure to synthesize post-spinel Si3Na. The heat capacity, thermal expansion and bulk modulus of the new phases are computed as functions of pressure and temperature. The heat capacity of post-spinel Si3Na is large at high temperature and only weakly pressure dependent.

关键词： First-principles Nitride Elastic constant Phase transition

Surface and Volume Symmetry Energy Coefficients of a Neutron-Rich Nucleus

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Chinese Physics Letters 2012年第9期29卷 32-35页

作者： MA Chun-Wang YANG Ju-Bao YU Mian PU Jie WANG Shan-Shan WEI Hui-Ling Department of Physics Henan Normal UniversityXinxiang 453007 Department of Life Sciences and Technology Xinxiang Medical UniversityXinxiang 453003 Department of Nuclear Physics Shanghai Institute of Applied PhysicsChinese Academy of SciencesShanghai 201800

Using an isobaric method,the symmetry-energy coefficient(asym)of a neutron-rich nucleus is obtained from experimental binding *** shell effects are shown in a^(*)_(sym)/A≡4asym/A of nuclei.A(sub)magic neutron magic number N=40 is suggested in a very neutron-rich nucleus,and a^(*)_(sym)/A of a nucleus is found to decrease when its mass *** a^(*)_(sym)/A of a very neutron-rich nucleus with large mass *** volume-symmetry coefficients(b_(v))and surface-symmetry coefficients(b_(s))of a neutron-rich nucleus are extracted from a sym*/A by a correlation a^(*)_(sym)/A=bv/A-b s/A^(4/3).It is found that bv and bs decrease when the nucleus becomes more neutron-rich,and tend to saturate in the very neutron-rich nucleus.A linear correlation between b v and bs is obtained in nuclei with different neutron-excess I,and bv of I>7 nuclei is found to coincide with the results of infinite nuclear matter a sym=32±4 MeV,and bs/bv of the nucleus is found to coincide with the results of the finite-range liquid-drop model results.

关键词： symmetry infinite coincide