期刊文献+
共找到16篇文章
< 1 >
每页显示 20 50 100
汉密尔顿及其广义适合度理论 被引量:3
1
作者 罗力群 《自然辩证法研究》 CSSCI 北大核心 2016年第2期94-97,共4页
英国进化生物学家汉密尔顿提出的广义适合度理论寓居于自然选择理论框架之内,是解释有机体社会行为进化的一般理论,主要的思想突破在于开辟了基因之眼看世界的风气。该理论是生物学家研究生物社会行为进化的理论基石,也是人类社会行为... 英国进化生物学家汉密尔顿提出的广义适合度理论寓居于自然选择理论框架之内,是解释有机体社会行为进化的一般理论,主要的思想突破在于开辟了基因之眼看世界的风气。该理论是生物学家研究生物社会行为进化的理论基石,也是人类社会行为进化研究的重要理论工具。 展开更多
关键词 汉密尔顿 广义适合理论 社会行为进化 基因之眼看世界
原文传递
具有周期扰动的差分方程的周期解 被引量:1
2
作者 李自强 刘金枝 《邵阳学院学报(自然科学版)》 2005年第3期2-3,共2页
考虑了一类扰动的差分方程:x(n+1)-x(n)=b(n,xn)+f(n,xn).利用广义度理论证明了方程在对应齐次线性方程只有平凡的N周期解的情况下至少存在一个N周期解.应用此结果,得到了周期解的存在唯一性准则.
关键词 广义度理论 差分方程 周期解
下载PDF
Chemical bonding and elastic properties of quaternary arsenide oxides YZnAsO and LaZnAsO investigated by first principles
3
作者 施毅敏 叶绍龙 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第6期1378-1382,共5页
The structural parameters, chemical bonding and elastic properties of the tetragonal phase quaternary arsenide oxides YZnAsO and LaZnAsO were investigated by using density-functional theory (DFT) within generalized ... The structural parameters, chemical bonding and elastic properties of the tetragonal phase quaternary arsenide oxides YZnAsO and LaZnAsO were investigated by using density-functional theory (DFT) within generalized gradient approximation (GGA). The GGA calculated structural parameters are in agreement with the experimental results. Population analysis suggests that the chemical bonding in YZnAsO and LaZnAsO can be classified as a mixture of ionic and covalent characteristic. Single-crystal elastic constants were calculated and the polycrystalline elastic modules were estimated according to Voigt, Reuss and Hill's approximations (VRH). The result shows that both YZnAsO and LaZnAsO are relatively soft materials exhibiting ductile behavior. The calculated polycrystalline elastic anisotropy result shows that LaZnAsO is more anisotropy in compressibility and YZnAsO is more anisotropy in shear. 展开更多
关键词 YZnAsO LaZnAsO chemical bonding elastic properties density-functional theory generalized gradientapproximation Voigt Reuss and Hill's approximations
下载PDF
生物社会视角下的民族问题研究引论
4
作者 罗力群 《社会科学论坛》 2020年第4期187-194,共8页
该文介绍了分子遗传学和进化生物学进路对民族问题的一些经验研究,也介绍了可供民族问题研究者选用的一个理论框架,即现代进化论的框架。生物社会视角下的民族研究可以帮助现有的民族研究澄清一些重要的事实,也可能为我们带来其他一些... 该文介绍了分子遗传学和进化生物学进路对民族问题的一些经验研究,也介绍了可供民族问题研究者选用的一个理论框架,即现代进化论的框架。生物社会视角下的民族研究可以帮助现有的民族研究澄清一些重要的事实,也可能为我们带来其他一些重要的洞见。作者希望能够抛砖引玉,唤起更多学者对此类研究的关注,以期丰富和充实现有的民族研究,为更好地认识民族问题,处理民族关系贡献一份力量。 展开更多
关键词 民族问题研究 生物社会视角 分子遗传学 广义适合理论 民族多样性
下载PDF
First principles study on electronic structure and optical properties of quaternary arsenide oxides YZnAsO and LaZnAsO 被引量:1
5
作者 施毅敏 叶绍龙 《Journal of Central South University》 SCIE EI CAS 2011年第4期998-1003,共6页
The electronic structure and optical properties of the tetragonal phase quaternary arsenide oxides YZnAsO and LaZnAsO were studied using density-functional theory(DFT) within generalized gradient approximation(GGA).Th... The electronic structure and optical properties of the tetragonal phase quaternary arsenide oxides YZnAsO and LaZnAsO were studied using density-functional theory(DFT) within generalized gradient approximation(GGA).The band structure along the higher symmetry axes in the Brillouin zone,the density of states(DOS) and the partial density of states(PDOS) were presented.The calculated energy band structures show that both YZnAsO and LaZnAsO are indirect gap semiconductors with band gap of 1.173 1 eV and 1.166 5 eV,respectively.The DOS and PDOS show the hybridization of Y-O/La-O atom orbits and Zn-As atom orbits.The dielectric function,reflectivity,absorption coefficient,refractive index,electron energy-loss function and optical conductivity were presented in an energy range from 0 to 25 eV for discussing the optical properties of YZnAsO and LaZnAsO. 展开更多
关键词 YZnAsO/LaZnAsO density-functional theory generalized gradient approximation electronic structure optical properties
下载PDF
Electronic Structure Magnetic Properties and Optical Properties of Co-doped AIN from First Principles 被引量:2
6
作者 赵龙 芦鹏飞 +5 位作者 俞重远 郭晓涛 叶寒 袁桂芳 沈阅 刘玉敏 《Communications in Theoretical Physics》 SCIE CAS CSCD 2011年第5期893-900,共8页
The electronic structure, magnetic properties, and optical properties of Co-doped AIN are investigated based upon the Perdew-Burke-Ernzerhof form of generalized gradient approximation within the density functional the... The electronic structure, magnetic properties, and optical properties of Co-doped AIN are investigated based upon the Perdew-Burke-Ernzerhof form of generalized gradient approximation within the density functional theory. The band gaps narrowing of AI1-x Cox N are found with the increase of Co concentrations. The analyses of the band structures and density of states show that AI1-xCoxN alloys exhibit a halfometallie character. Moreover, we have succeeded in demonstrating that Co doped AIN system in x = 0.125 is always antiferromagnetie, which is in good agreement with the experimental results. Besides, it is shown that the insertion of Co atom leads to redshift of the optical absorption edge. Finally, the optical constants of pure A1N and AI1-xCoxN alloy, such as loss function, refractive index and reflectivity, are discussed. 展开更多
关键词 electronic structure magnetic properties optical properties Co-doped A1N first principles
下载PDF
First principles study on electronic structure and optical properties of novel Na-hP4 high pressure phase 被引量:1
7
作者 施毅敏 叶绍龙 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第6期1092-1096,共5页
The electronic structure and optical properties of novel Na-hP4 high pressure phase at different pressures(260,320,400 and 600 GPa)were investigated by the density functional theory(DFT)with the generalized gradient a... The electronic structure and optical properties of novel Na-hP4 high pressure phase at different pressures(260,320,400 and 600 GPa)were investigated by the density functional theory(DFT)with the generalized gradient approximation(GGA)for the exchange and correlation energy.The band structure along the higher symmetry axes in the Brillouin zone,the density of states(DOS) and the partial density of states(PDOS)were presented.The band gap increases and the energy band expands to some extent with the pressure increasing.The dielectric function,reflectivity,energy-loss function,optical absorption coefficient,optical conductivity, refractive index and extinction coefficient were calculated for discussing the optical properties of Na-hP4 high pressure phase at different pressures. 展开更多
关键词 first principles novel Na-hP4 phase high pressure phase density functional theory electronic structure optical properties
下载PDF
Photoabsorption Spectra of Si_n and Si_nO (n ≤ 5)
8
作者 AN Fang-Fang ZHANG Hong CHENG Xin-Lu 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第4期751-755,共5页
The photoabsorption spectra have been calculated for Sis and SilO (n ≤ 5) clusters using time-dependent density-function theory. Our studies suggest that Sin-1 O clusters are relatively stable than those of corresp... The photoabsorption spectra have been calculated for Sis and SilO (n ≤ 5) clusters using time-dependent density-function theory. Our studies suggest that Sin-1 O clusters are relatively stable than those of corresponding Sis clusters. Moreover, substantial differences are observed among the absorption spectra of different molecules in the energy region (0 - 8 eV). Comparing two different exchange-correlation potentials, local-density and generalized-gradient approximations, both calculated optical spectra present the same spectral feature. 展开更多
关键词 Sin clusters SinO clusters TDDFT photoabsorption spectra
下载PDF
First principles calculation on electronic structure,chemical bonding,elastic and optical properties of novel tungsten triboride
9
作者 王一夫 夏庆林 余燕 《Journal of Central South University》 SCIE EI CAS 2014年第2期500-505,共6页
The electronic structures,chemical bonding,elastic and optical properties of the novel hP24 phase WB3 were investigated by using density-functional theory(DFT) within generalized gradient approximation(GGA).The calcul... The electronic structures,chemical bonding,elastic and optical properties of the novel hP24 phase WB3 were investigated by using density-functional theory(DFT) within generalized gradient approximation(GGA).The calculated energy band structures show that the hP24 phase WB3 is metallic material.The density of state(DOS) and the partial density of state(PDOS) calculations show that the DOS near the Fermi level is mainly from the W 5d and B 2p states.Population analysis suggests that the chemical bonding in hP24-WB3 has predominantly covalent characteristics with mixed covalent-ionic characteristics.Basic physical properties,such as lattice constant,bulk modulus,shear modulus and elastic constants Cij were calculated.The elastic modulus E and Poisson ratio υ were also predicted.The results show that hP24-WB3 phase is mechanically stable and behaves in a brittle manner.Detailed analysis of all optical functions reveals that WB3 is a better dielectric material,and reflectivity spectra show that WB3 can be promised as good coating material in the energy regions of 8.5-11.4 eV and 14.5-15.5 eV. 展开更多
关键词 hP24-WB3 first principles calculation electronic structure chemical bonding elastic properties optical properties
下载PDF
Electronic Structure and Optical Properties of Antimony-Doped SnO_2 from First-Principle Study 被引量:2
10
作者 LU Peng-Fei SHEN Yue +5 位作者 YU Zhong-Yuan ZHAO Long LI Qiong-Yao MA Shi-Jia HAN Li-Hong LIU Yu-Min 《Communications in Theoretical Physics》 SCIE CAS CSCD 2012年第1期145-150,共6页
A first-principles study has been performed to calculate the electronic and optical properties of the SbxSn1xO system.The simulations are based upon the method of generalized gradient approximations with the Perdew-Bu... A first-principles study has been performed to calculate the electronic and optical properties of the SbxSn1xO system.The simulations are based upon the method of generalized gradient approximations with the Perdew-Burke-Ernzerhof form in the framework of density functional theory.The supercell structure shows a trend from expanding to shrinking with the increasing Sb concentration.The increasing Sb concentration induces the band gap narrowing.Optical transition has shifted to the low energy range with increasing Sb concentration.Other important optical constants such as the dielectric function,reflectivity,refractive index,and electron energy loss function for Sb-doped SnO2 are discussed.The optical absorption edge of SnO2 doped with Sb also shows a redshift. 展开更多
关键词 first-principle methods Sb-doped SnO2 electronic structure optical properties
下载PDF
Physical Properties of Ⅲ-Antiminodes—a First Principles Study 被引量:4
11
作者 Rashid Ahmed Fazal-e-Aleem +2 位作者 S.Javad Hashemifar Haris Rashid H.Akbarzadeh 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第9期527-533,共7页
A comprehensive first principles study of III-Antimonide binary compounds is hardly found in literature. We report a broad study of structural and electronic properties of boron antimonide (BSb), aluminium antimoni... A comprehensive first principles study of III-Antimonide binary compounds is hardly found in literature. We report a broad study of structural and electronic properties of boron antimonide (BSb), aluminium antimonide (AlSb), gallium antimonide (GaSb) and indium antimonide (InSb) in zineblende phase based on density functional theory (DFT). Our calculations are based on Full-PotentiM Lineaxized Augmented Plane wave plus local orbitals (FP- L(APWq-lo)) method. Different forms of exchange-correlation energy functional and corresponding potential are employed for structural and electronic properties. Our computed results for lattice parameters, bulk moduli, their pressure derivatives, and cohesive energy are consistent with the available experimental data. Boron antimonide is found to be the hardest compound of this group. For band structure calculations, in addition to LDA and GGA, we used GGA-EV, an approximation employed by Engel and Vosko. The band gap results with GGA-EV are of significant improvement over the earlier work. 展开更多
关键词 III-antimonides DFT FPLAPW exchange correlation functional structural properties of solids band structure of crystalline solids
下载PDF
Magnetism and Sound Velocities of Iron Carbide (Fe3C) under Pressure
12
作者 Zhao-yi Zeng Cui-e Hu +1 位作者 Xun Liu Ling-cang Cai 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2014年第3期297-301,共5页
The elastic property and sound velocity of FeaC under high pressure are investigated by using the spin-polarized generalized gradient approximation within density-functional theory. It is found that the magnetic phase... The elastic property and sound velocity of FeaC under high pressure are investigated by using the spin-polarized generalized gradient approximation within density-functional theory. It is found that the magnetic phase transition from the ground ferromagnetic (FM) state to the nonmagnetic (NM) state occurs at ~73 GPa. Based on the predicted Hugoniot of Fe3C, we calculate the sound velocities of FM-Fe3C and NM-Fe3C from elastic constants. Compared with pure iron, NM-FeaC provides a better match of compressional and shear sound velocities with the seismic data of the inner core, supporting carbon as one of the light elements in the inner core. 展开更多
关键词 ALLOY Sound velocity Density functional theory
下载PDF
具有周期扰动的泛函微分方程的周期解 被引量:4
13
作者 马世旺 庾建设 王志成 《科学通报》 EI CAS CSCD 北大核心 1998年第13期1386-1389,共4页
利用广义度理论证明了一类具有周期扰动的泛函微分方程在对应齐次线性方程没有非平凡周期解的情况下至少存在一个周期解 .推广了这方面的已知结果 .
关键词 广义度理论 泛函微分方程 周期解 周期扰动
原文传递
A first-principles study of the structural,electronic and elastic properties of solid nitromethane under pressure 被引量:4
14
作者 CHANG Jing ZHOU XiaoLin +1 位作者 ZHAO GuoPing WANG Li 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2013年第10期1874-1881,共8页
The structural,electronic and elastic properties of solid nitromethane are investigated under pressure by performing first-principles density functional theory(DFT)calculations within the generalized gradient approxim... The structural,electronic and elastic properties of solid nitromethane are investigated under pressure by performing first-principles density functional theory(DFT)calculations within the generalized gradient approximation(GGA)and the local density approximation(LDA).The obtained ground state structure properties are found to be consistent with existing experimental and theoretical results.The pressure-induced variations of structure parameters(a,b,c and V)indicate that the solid nitromethane has an anisotropic compressibility,and the compression along the c direction is more difficult than along a and b directions.From the vibration curves of intermolecular bond length and bond angle,we find that the C—N bond is the most sensitive among these bonds under pressure,suggesting that the C—N bonds may be broken first under external loading.The influence of pressure on the electronic properties of solid NM has been studied,indicating that solid NM is an insulating compound with a large indirect band gap and tends to be a semiconductor with increasing pressure.Finally,we predict the elastic constants and their pressure dependence for the solid NM with the bulk modulus,Young’s modulus,shear modulus and the Poisson’s ratio derived. 展开更多
关键词 density functional theory crystal structure electronic structure elastic constants NITROMETHANE
原文传递
First-principles investigation of the effects of B impurities on the mechanical properties of NiAl intermetallics 被引量:4
15
作者 HU XueLan LIU Xu +2 位作者 XU Zhou LIANG JiaChang WANG TianMin 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2011年第5期809-814,共6页
We have investigated the effects of B impurities on the structure and mechanical properties of NiA1 intermetallics by using a first-principles pseudopotential total-energy method, based on the density functional theor... We have investigated the effects of B impurities on the structure and mechanical properties of NiA1 intermetallics by using a first-principles pseudopotential total-energy method, based on the density functional theory with a generalized gradient approximation. We found that the impurity B atoms can either replace Ni atoms or Al atoms or both, depending on the surround- ing environment. We demonstrated that the presence of B will cause an increase in brittleness and a decrease in the ductility of NiAI for the Al-substitutional case, while causing an increase in the ductility of NiAl for the Ni-subtitutional case, based on the calculated elastic constants and the empirical criterions. This indicates that the effects of B impurities on the mechanical prop- erties of NiAl intermetallics are quite composition-dependent. 展开更多
关键词 NiAl intermetallics B impurity MECHANICAL FIRST-PRINCIPLES
原文传递
Hydrostatic pressure influence on magnetic phase diagram and structural parameters of SrTcO_3 from first-principles calculations 被引量:2
16
作者 MA ChunLan ZANG TaoCheng WANG XiaoDan 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2012年第7期1253-1257,共5页
The effects of hydrostatic pressure of SrWeO3 are investigated by means of generalized gradient approximation (GGA) plus on-site Coulomb interaction corrections (GGA+U) method within the framework of density func... The effects of hydrostatic pressure of SrWeO3 are investigated by means of generalized gradient approximation (GGA) plus on-site Coulomb interaction corrections (GGA+U) method within the framework of density functional theory (DFT). Magnetic phase diagrams and structural parameters of SrTcO3 as a function of pressure are predicted. The magnetic ground state of SrTcO3 is found to keep in a G-type antiferromagnetic (G-AFM) structure under the pressure varying from 0 to 100 GPa. With the increase of the pressure, magnetic exchange energy increases, indicating a higher magnetic ordering temperature for SrTcO3 under a larger pressure. Besides the volume of the unit cell, lattice constants, and the bond length, the angles between typical Tc-O-Tc and Sr-O-Sr also decrease with the pressure, leading to strong structural distortions. Very obvious displace- ments of Sr and O atoms are observed under the pressure. Our work provides necessary understanding on electronic structures of SrTcO3 under high pressures. 展开更多
关键词 crystal structures SEMICONDUCTORS magnetic materials hydrostatic pressure first-principles calculations
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部