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一般流体及含超临界组元混合物表面张力的密度梯度理论模型 被引量:1
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作者 闵琪 林鸿 +1 位作者 段远源 宋艺新 《工程热物理学报》 EI CAS CSCD 北大核心 2007年第z1期65-68,共4页
表面张力是非常重要的物性参数之一,特别对于沸腾和凝结换热的计算是必不可少的。但目前的研究成果主要集中于纯物质,对有重要工程应用前景的混合工质研究还很少。本文应用密度梯度理论,结合比容平移后的Peng-Robinson方程建立了混合物... 表面张力是非常重要的物性参数之一,特别对于沸腾和凝结换热的计算是必不可少的。但目前的研究成果主要集中于纯物质,对有重要工程应用前景的混合工质研究还很少。本文应用密度梯度理论,结合比容平移后的Peng-Robinson方程建立了混合物的表面张力模型,该模型不含有任何需要表面张力实验数据回归确定的经验可调系数。计算结果表明,本文建立的模型具有很好的通用性和计算精度,能在广泛的温度范围内较好地再现一般流体混合物和含超临界组元混合物的表面张力数据。 展开更多
关键词 表面张力 密度梯度理论 二元混合物 状态方程
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含醇二元体系表面张力预测模型
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作者 闵琪 段远源 +1 位作者 林鸿 宋艺新 《工程热物理学报》 EI CAS CSCD 北大核心 2009年第1期21-25,共5页
表面张力是重要的物性参数之一,与人们的生产生活密切相关。醇类及其混合物具有重要的工业应用价值。含醇混合物作为特殊的缔合体系,由于氢键的存在,性质复杂。本文应用密度梯度理论结合比容平移后的Peng-Robinson状态方程,回归了醇、... 表面张力是重要的物性参数之一,与人们的生产生活密切相关。醇类及其混合物具有重要的工业应用价值。含醇混合物作为特殊的缔合体系,由于氢键的存在,性质复杂。本文应用密度梯度理论结合比容平移后的Peng-Robinson状态方程,回归了醇、水纯净物的作用因子关联式系数,建立了混合物的表面张力预测模型,计算了含醇二元缔合体系的表面张力,该模型不含有任何需要混合物表面张力实验数据回归确定的经验可调参数,对绝大多数含醇混合物具有很好的通用性和计算精度。 展开更多
关键词 表面张力 密度梯度理论 二元混合物
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Chemical bonding and elastic properties of quaternary arsenide oxides YZnAsO and LaZnAsO investigated by first principles
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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
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脂肪酸酯类表面张力的模型研究
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作者 王晓雷 张瑶 商巧燕 《聊城大学学报(自然科学版)》 2019年第6期54-58,共5页
生物柴油具有良好的可再生能力、可降解性和环境友好性,其在发动机缸内的喷雾燃烧过程是生物柴油应用的关键步骤,雾化过程中形成液滴的大小与表面张力密切相关.因此,表面张力是生物柴油应用前景的关键参数,脂肪酸酯是生物柴油的主要成分... 生物柴油具有良好的可再生能力、可降解性和环境友好性,其在发动机缸内的喷雾燃烧过程是生物柴油应用的关键步骤,雾化过程中形成液滴的大小与表面张力密切相关.因此,表面张力是生物柴油应用前景的关键参数,脂肪酸酯是生物柴油的主要成分.本研究通过查阅大量国内外文献,分析整理了19种脂肪酸酯的表面张力实验数据.采用密度梯度理论和Peng-Robinson(PR)状态方程结合,提出表面张力的估算模型,该模型的提出将为生物柴油表面张力的预测提供理论依据. 展开更多
关键词 生物柴油 脂肪酸酯 表面张力 密度梯度理论 状态方程
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Electronic Structure Magnetic Properties and Optical Properties of Co-doped AIN from First Principles 被引量:2
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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
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First principles study on electronic structure and optical properties of novel Na-hP4 high pressure phase 被引量:1
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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
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First principles study on electronic structure and optical properties of quaternary arsenide oxides YZnAsO and LaZnAsO 被引量:1
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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
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Electronic Structure and Optical Properties of Antimony-Doped SnO_2 from First-Principle Study 被引量:2
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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
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Physical Properties of Ⅲ-Antiminodes—a First Principles Study 被引量:4
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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
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Photoabsorption Spectra of Si_n and Si_nO (n ≤ 5)
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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
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Magnetism and Sound Velocities of Iron Carbide (Fe3C) under Pressure
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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
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First principles calculation on electronic structure,chemical bonding,elastic and optical properties of novel tungsten triboride
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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
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HCs/HCs和HCs/CO_2二元体系表面张力的预测
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作者 朱君悦 段远源 +1 位作者 闵琪 林鸿 《工程热物理学报》 EI CAS CSCD 北大核心 2012年第6期925-928,共4页
表面张力是非常重要的物性之一,本文将比容平移后的PR状态方程和密度梯度理论结合,建立了不依赖于混合物表面张力和气液相平衡实验数据的二元混合物表面张力的纯预测模型。对碳氢/碳氢和碳氢/二氧化碳二元体系的表面张力进行了预测,结... 表面张力是非常重要的物性之一,本文将比容平移后的PR状态方程和密度梯度理论结合,建立了不依赖于混合物表面张力和气液相平衡实验数据的二元混合物表面张力的纯预测模型。对碳氢/碳氢和碳氢/二氧化碳二元体系的表面张力进行了预测,结果表明,本文模型对两组元碳原子数相差不大或者两组元分子结构满足链状和环状或环状和环状组合的碳氢/碳氢二元体系有较高的预测精度,同时模型对碳氢/二氧化碳二元体系表面张力也有较好的预测能力。 展开更多
关键词 表面张力 密度梯度理论 二元混合物 碳氢化合物 二氧化碳
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CO_2-甲醇和CO_2-乙醇体系的界面性质
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作者 付东 《中国科学:化学》 CAS CSCD 北大核心 2011年第5期821-827,共7页
在交叉缔合的均相状态方程的基础上,结合密度梯度理论(density gradient theory,DGT),建立了适用于CO2-甲醇和CO2-乙醇二元体系界面性质研究的状态方程,对CO2-乙醇体系表面张力的关联结果与实验值吻合良好.阐明了CO2分子与甲醇分子和乙... 在交叉缔合的均相状态方程的基础上,结合密度梯度理论(density gradient theory,DGT),建立了适用于CO2-甲醇和CO2-乙醇二元体系界面性质研究的状态方程,对CO2-乙醇体系表面张力的关联结果与实验值吻合良好.阐明了CO2分子与甲醇分子和乙醇分子之间的交叉缔合作用对二元体系表面张力计算结果的影响,以及界面相中CO2与醇羟基之间的交叉缔合与温度和压力之间的关系. 展开更多
关键词 CO2-甲醇 CO2-乙醇 交叉缔合 密度梯度理论 界面性质
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First-principles investigation of the effects of B impurities on the mechanical properties of NiAl intermetallics 被引量:4
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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
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A first-principles study of the structural,electronic and elastic properties of solid nitromethane under pressure 被引量:4
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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
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Hydrostatic pressure influence on magnetic phase diagram and structural parameters of SrTcO_3 from first-principles calculations 被引量:2
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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
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