胡望宇
主要的研究方向有原子尺度材料设计理论,纳米物理,晶体缺陷,表面聚集、吸附与催化,轻元素在金属与合金中的行为和表面涂层。
个性化签名
- 姓名:胡望宇
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学术头衔:
博士生导师, 优秀教师/优秀教育工作者, 教育部“新世纪优秀人才支持计划”入选者
- 职称:-
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学科领域:
材料科学
- 研究兴趣:主要的研究方向有原子尺度材料设计理论,纳米物理,晶体缺陷,表面聚集、吸附与催化,轻元素在金属与合金中的行为和表面涂层。
胡望宇,湖南大学教授,博士生导师, 湖南大学高性能计算中心主任,主要从事材料科学和凝聚态物理方面的研究。民革湖南省委会副主任委员,政协九届湖南省委员会常务委员。1985年毕业于湖南大学,获理学学士学位; 1989年在湖南大学获理论物理理学硕士学位;1996年在中国科学院金属研究所获材料学工学博士学位。1997-1999年在中南大学粉末冶金研究所国家重点实验室作博士后。1999年在湖南大学晋升为教授,同年在英国皇家学会资助下赴英国Liverpool大学原子模拟实验室合作研究3个月。2000年获教育部“跨世纪优秀人才计划培养基金”和“骨干教师资助计划”资助。2001年评为博士生导师。2001年在日本学术振兴会资助下赴日本丰桥技术科学大学合作研究两年。2004年11月以访问教授身份在日本明治大学讲学1个月。讲授过“固体物理”、“金属学”“材料科学基础”等多门课程。主要的研究方向有原子尺度材料设计理论,纳米物理,晶体缺陷,表面聚集、吸附与催化,轻元素在金属与合金中的行为和表面涂层。国家自然科学基金,教育部科学技术基金,回国留学人员基金,博士点基金,湖南省科技厅自然科学基金,湖南省教育厅科学技术基金等评审专家.国内外学术期刊Applied Surface Science, Journal of Molecular Structure, 中国科学, 金属学报, 物理学报, 中国有色金属学报, 化学物理学报等审稿人.围绕分析型嵌入原子模型(EAM)展开了一系列系统而深入的研究工作。发展完成了典型金属的分析型EAM多体势的构筑,模拟研究了多种晶体缺陷的特征,晶格振动和热物性等基本物性,表面振动特性,对典型金属间化合物的缺陷特性和扩散性能,二元合金的热性能,表面聚集和纳米金属与合金等进行了系统的计算。在华夏英才基金资助下,出版了专著《嵌入原子方法理论及其在材料科学中的应用——原子尺度材料设计理论》,获第十四届中国图书奖。先后主持或参加了30余项科研项目, 发表论文170余篇, SCI和EI各收录90余篇次,引用300余次。2次获国家机械工业局科技进步二等奖,1次获机械电子工业部科技进步三等奖。
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718
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成果数
19
【期刊论文】Melting temperature: From nanocrystalline to amorphous phase
胡望宇, Shifang Xiao, Wangyu Hu, Jianyu Yang
THE JOURNAL OF CHEMICAL PHYSICS 125, 184504 (2006),-0001,():
-1年11月30日
By extrapolating the mean grain size of nanocrystal to an infinitesimal value, an amorphous phase has been obtained from the Voronoi construction. The molecular dynamics simulations indicated that for nanocrystal, the grain size variation of melting temperature exhibits two characteristic regions. As mean grain size above about 4 nm for Ag, the melting temperatures decrease with decreasing grain size. However, with grain size further shrinking, the melting temperatures almost keep a constant. This is because the dominant factor on the melting temperature of nanocrystal shifts from grain phase to grain boundary. As a result of fundamental difference in structure, the amorphous phase has a much lower solid-to-liquid transformation temperature than that of nanocrystal.
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【期刊论文】Comparative study of microstructural evolution during melting and crystallization
胡望宇, Shifang Xiao, Wangyu Hu
THE JOURNAL OF CHEMICAL PHYSICS 125, 014503 (2006),-0001,():
-1年11月30日
Molecular dynamics simulations, with the interaction between atoms described by a modified analytic embedded atom method, have been performed to obtain the atomic-scale details of isothermal melting in nanocrystalline Ag and crystallization from supercooled liquid. The radial distribution function and common neighbor analysis provide a visible scenario of structural evolution in the process of phase transition. The results indicate that melting at a fixed temperature in nanocrystalline materials is a continuous process, which originates from the grain boundary network. With the melting developing, the characteristic bond pairs 555 , 433 , and 544 , existing in liquid or liquidlike phase, increase approximately linearly till completely melted. The crystallization from supercooled liquid is characterized by three characteristic stages: nucleation, rapid growth of nucleus, and slow structural relaxation. The homogeneous nucleation occurs at a larger supercooling temperature, which has an important effect on the process of crystallization and the subsequent crystalline texture. The kinetics of transition from liquid to solid is well described by the Johnson-Mehl-Avrami equation.
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【期刊论文】Melting Behaviors of Nanocrystalline Ag
胡望宇, Shifang Xiao, Wangyu Hu, Jianyu Yang
J. Phys. Chem. B 2005, 109, 20339-20342,-0001,():
-1年11月30日
In the atomic scale, the melting behaviors of nanocrystalline Ag with mean grain size ranging from 3.03 to 12.12 nm have been investigated with molecular dynamics simulations, and a method to determine the melting temperatures of the infinite polycrystalline nanostructured materials is presented. It is found that the melting in nanostructured polycrystals starts from their grain boundaries, and the relative numbers of the three typical bonded pairs, (1551), (1431), and (1541), existing in the liquid phase, increase rapidly with the evolvement of melting. The melting temperatures of nanocrystalline Ag decrease with decreasing mean grain size, and it can be estimated from the size-dependent melting temperature of the corresponding nanoparticles.
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【期刊论文】Shell and subshell periodic structures of icosahedral nickel nanoclusters
胡望宇, Zhi Zhang, Wangyu Hu, Shifang Xiao
THE JOURNAL OF CHEMICAL PHYSICS 122, 214501 (2005),-0001,():
-1年11月30日
Using the modified analytic embedded atom method and molecular dynamics, the binding energies and their second order finite differences stability functionsd of icosahedral Ni clusters with shell and subshell periodicity are studied in detail via atomic evolution. The results exhibit shell and sub shell structures of the clusters with atoms from 147 to 250 000, and the atomic numbers corresponding to shell or subshell structures are in good agreement with the experimental magic numbers obtained in time-of-flight mass spectra of threshold photoionization, and Martin’s theoretical proposition of progressive formation of atomic umbrellas. Clusters with size from 147 to 561 atoms are energetically investigated via one-by-one atomic evolution and their magic numbers are theoretically proved. For medium-size Ni clusters with 561 to 2057 atoms, the prediction of magic numbers with atomic numbers is performed on the basis of umbrellalike subshell growth in near face-edge-vertex order. The similarity of the energy curves makes it possible to extend the prediction to even larger Ni nanoclusters in hierarchical Mackay icosahedral configurations.
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胡望宇, Zhi Zhang, , Wangyu Hu, Shifang Xiao
PHYSICAL REVIEW B 73, 125443 (2006),-0001,():
-1年11月30日
The surface premelting, melting behavior, melting competition, and structural transition of shell-closed icosahedral ICO and cuboctahedral CUB nickel clusters with atoms from 309 to 2057 were discussed extensively by using quantitative caloric curves based on the modified analytic embedded atom method and molecular dynamics, qualitative three-dimensional structural visualization of symmetric truncation, and the radial number distribution function. These studies reveal that smaller clusters melt at lower temperatures and a solid-to-solid structural transition occurs from CUB to ICO structure during melting process. The shell-closed ICO clusters could only be preferred until 923 atoms at temperatures no higher than 1380 K, which is in agreement with the experiments. The melting temperature of larger clusters would depend on their starting structures, which can be attributed to surface premelting.
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【期刊论文】Size effect on alloying ability and phase stability of immiscible bimetallic nanoparticles
胡望宇, S. Xiao, W. Hua, W. Luo, Y. Wu, X. Li, and H. Deng
Eur. Phys. J B 54, 479-484 (2006),-0001,():
-1年11月30日
In the present paper, the surface and size effects on the alloying ability and phase stability of immiscible alloy nanoparticles have been studied with calculating the heats of formation of Au-Pt alloy nanoparticles from the single element nanoparticles of their constituents (Au and Pt) with a simple thermodynamic model and an analytic embedded atom method. The results indicated that, besides the similar compositional dependence of heat of formation as in bulk alloys, the heat of formation of alloy nanoparticles exhibits notable size-dependence, and there exists a competition between size effect and compositional effect on the heat of formation of immiscible system. Contrary to the positive heat of formation for bulkimmiscible alloys, a negative heat of formation may be obtained for the alloy nanoparticles with a small size or dilute solute component, which implies a promotion of the alloying ability and phase stability of immiscible system on a nanoscale. The surface segregation results in an extension of the size range of particles with a negative heat of formation. The molecular dynamics simulations have indicated that the structurally and compositionally homogeneous Au Pt nanoparticles tend to form a core-shell structure with temperature increasing.
Nanoscale materials, Solubility,, segregation,, and mixing, phase separation
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胡望宇, Jianyu Yang, Wangyu Hu, Huiqiu Deng, Dongliang Zhao
J. Yang et al. Surface Science 572 (2004) 439-448,-0001,():
-1年11月30日
Using molecular dynamics simulations and a modified analytic embedded-atom method (MAEAM), the relaxations and vibrations of Ni(977) surface are studied in the temperature range of 100–1500K, The calculated results for the temperature dependence of phonon frequencies, line-width and the mean square amplitude show that the anharmonic effects are small for temperatures up to 900K. The calculated interlayer separation for the first and second surface decreases, and the distance along the x direction increases between the topmost and second surface, with increasing temperature. In addition, the calculated layer structure factor indicates that the Ni(977) surface is well ordered and does not premelt up to a temperature of 1700K.
Nickel, Molecular dynamics, Surface relaxation and reconstruction, Vicinal single crystal surfaces, Electron density, excitation spectra calculations
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【期刊论文】Atomistic simulation of the segregation profiles in Mo–Re random alloys
胡望宇, Huiqiu Deng, Wangyu Hu, Xiaolin Shu, Bangwei Zhang,
H. Deng et al. Surface Science 543 (2003) 95-102,-0001,():
-1年11月30日
Simple modified analytic embedded atom method(MAEAM)many-body potentials are constructed for bcc molybdenum and hcp rhenium metal in the present paper. Using the MAEAM and analytic alloy potentials, the segregation profiles for(100)surface in Mo–Re bcc-type random alloys were studied with Monte Carlo simulation technology. The simulation results show that the topmost surface is almost completely enriched with molybdenum, the subsurface is depleted of molybdenum, and the molybdenum concentration oscillates toward the bulk value. The simulation results are in good agreement with available low-energy electron diraction and low-energy ion scattering experiment data, and the calculations from tight-binding Ising model.
Surface segregation, Semi-empirical models and model calculations, Monte Carlo simulations, Alloys, Molybdenum, Rhenium
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【期刊论文】Melting evolution and diffusion behavior of vanadium nanoparticles
胡望宇, Wangyu Hu, Shifang Xiao, Jianyu Yang, and Zhi Zhang
Eur. Phys. J. B 45, 547-554 (2005),-0001,():
-1年11月30日
Molecular dynamics calculations have been performed to study the melting evolution, atomic diffusion and vibrational behavior of bcc metal vanadium nanoparticles with the number of atoms ranging from 537 to 28475 (diameters around 2-9 nm). The interactions between atoms are described using an analytic embedded-atom method. The obtained results reveal that the melting temperatures of nanoparticles are inversely proportional to the reciprocal of the nanoparticle size, and are in good agreement with the predictions of the thermodynamic liquid-drop model. The melting process can be described as occurring in two stages, firstly the stepwise premelting of the surface layer with a thickness of 2-3 times the perfect lattice constant, and then the abrupt overall melting of the whole cluster. The heats of fusion of nanoparticles are also inversely proportional to the reciprocal of the nanoparticle size. The diffusion is mainly localized to the surface layer at low temperatures and increases with the reduction of nanoparticle size, with the temperature being held constant. The radial mean square vibration amplitude (RMSVA) is developed to study the anharmonic effect on surface shells.
Nanoscale materials: clusters,, nanoparticles,, nanotubes,, and nanocrystals, Thermal properties of small particles,, nanocrystals,, nanotubes, Diffusion in nanoscale solids
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【期刊论文】Molecular dynamics simulations of grain growth in nanocrystalline Ag
胡望宇, Shifang Xiao, Wangyu Hu
S. Xiao, W. Hu. Journal of Crystal Growth 286 (2006) 512-517,-0001,():
-1年11月30日
Isothermal grain growth behaviors, including the effect of temperature and mean grain size, of nanocrystalline Ag are investigated using the molecular dynamics simulations with an analytical embedded atom potential. The atomistic simulations provide a level of atomic details on microscopic mechanism and process of grain growth that still remains inaccessible to experiments. The small grain size and high temperature accelerate the grain growth, it is the same as the conventional polycrystalline materials. The grain growth processes of nanocrystalline Ag are well characterized by a power-law growth curve, followed by a linear relaxation stage. Beside grain boundary migration and grain rotation mechanisms, the dislocations(or stacking faults)serve as the intermediate role in the grain growth process.
A1., Analytic embedded atom method, A1., Molecular dynamics, A2., Grain growth, B1., Nanocrystalline Ag
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