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Chinese Physics B 2018年第11期27卷 300-304页

作者：汪姚岑张岩 Yoshiyuki Kawazoe 沈军曹崇德 School of Natural and Applied Sciences Northwestern Polytechnical University Research & Development Institute of Northwestern Polytechnical University in Shenzhen Institute for Materials Research Tohoku University New Industry Creation Hatchery Center Tohoku University School of Materials Science and Engineering Tongji University

The addition of early transition metals（ETMs） into Fe-based amorphous alloys is practically found to be effective in reducing the α-Fe grain size in crystallization process. In this paper, by using ab initio molecular dynamics simulations, the mechanism of the effect of two typical ETMs（Nb and W） on nano-crystallization is studied. It is found that the diffusion ability in amorphous alloy is mainly determined by the bonding energy of the atom rather than the size or weight of the atom. The alloying of B dramatically reduces the diffusion ability of the ETM atoms, which prevents the supply of Fe near the grain surface and consequently suppresses the growth of α-Fe grains. Moreover, the difference in grain refining effectiveness between Nb and W could be attributed to the larger bonding energy between Nb and B than that between W and B.

关键词： ab initio molecular dynamics Fe-based amorphous alloys nano-crystallization atomic diffusion

Simulation of ab initio molecular dynamics of Shock Wave on Copper

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Chinese Physics Letters 2003年第12期20卷 2091-2093页

作者：张林蔡灵仓向士凯经福谦陈栋泉 LaboratoryforShockWaveandDetonationPhysicsResearch InstituteofFluidPhysicsPOBox919-102Mianyang621900 InstituteofAppliedPhysicsandComputationalMathematics POBox8009Beijing100088

The relation between particle velocity Up, up to 4km/s, and shock wave velocity Us in copper has been simulated with ab initio molecular dynamics. The simulated relationship without considering the correction of zero-point and finite temperature effects is Us = 4.23+1.53Up. After considering the correction the relation becomes Us = 4.08+1.53Up, which is consistent with the experimental result.

关键词： Simulation ab initio molecular dynamics Shock Wave Copper

Dissociation of liquid water on defective rutile TiO2 （110） surfaces using ab initio molecular dynamics simulations

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Frontiers of physics 2018年第3期13卷 53-59页

作者：王会丽胡振芃李晖 School of Physics Nankai University Tianjin 300071 China Beijing Advanced Innovation Center for Soft Matter Science and Engineering Beijing University of Chemical Technology Beijing 100029 China Institute of Physics Chinese Academy of Sciences Beijing 100190 China

In order to obtain a comprehensive understanding of both thermodynamics and kinetics of water dissociation on TiO2, the reactions between liquid water and perfect and defective rutile TiO2 （110） surfaces were investigated using ab initio molecular dynamics simulations. The results showed that the free-energy barrier （-4.4 kcal/mol） is too high for a spontaneous dissociation of water on the perfect rutile （110） surface at a low temperature. The most stable oxygen vacancy （VOl） on the rutile （110） surface cannot promote the dissociation of water, while other unstable oxygen vacancies can significantly enhance the water dissociation rate. This is opposite to the general understanding that Vol defects are active sites for water dissociation. Furthermore, we reveal that water dissociation is an exothermic reaction, which demonstrates that the dissociated state of the adsorbed water is thermodynamically favorable for both perfect and defective futile （110） surfaces. The dissociation adsorption of water can also increase the hydrophilicity of TiO2.

关键词： ab initio molecular dynamics rutile (110) free energy barrier spontaneous reaction exothermic reaction

Hydrogen Diffusion in Aluminum Melts: An ab initio molecular dynamics Study

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Journal of Wuhan University of Technology(Materials Science) 2012年第3期27卷 560-567页

作者：柳洋孙宝德 State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University

The diffusion process of hydrogen in aluminum melts was investigated by molecular dynamics simulation. The pair correlation function, first peak position, and coordination number was calculated and differences in the structural properties among Al-H, Cl-H, and Al-Cl pair were examined. The mechanism of chlorine on improving hydrogen diffusion was discussed. From an ab initio molecular dynamics calculations, the diffusivity of hydrogen in liquid aluminum as D（T）=（0.118×10-4 m2/s）exp（-0.316 eV/kT） is obtained, which is in good agreement with the experimental data. Correspondingly the diffusivity with presence of chlorine is promoted as D（T）=（0.09×10-4 m2/s）exp（-0.251 eV/kT）. It can be concluded that the diffusion of hydrogen in aluminum melts can be enhanced in the presence of chlorine.

关键词： ab initio molecular dynamics hydrogen in aluminum melts chlorine diffusion coefficient activation energy barrier

ab initio molecular dynamics Study of Polydimethylsiloxane Under Electric Field

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Ab Initio Molecular Dynamics Study of Polydimethylsiloxane U...

Zero-point fluctuation of hydrogen bond in water dimer from ab initio molecular dynamics

四川成都辐射研究与辐射工艺研讨会

作者： Chen Xiaojun,Luo Shunzhong, Huang Wei,Xu Yunshu (China Academy of Engineering Physics, P.O. Box. 919-214, Mianyang, Sichuan 621900, China)

Polydimethylsiloxane(PDMS) is a kind of main structure molecular of silicon rubber foam, which is widely used in sealing, vibration-absorption, heat insulation and acoustic insulation, owing to its go

关键词： PDMS ab initio molecular dynamics PBC

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Chinese Physics B 2020年第10期29卷 202-213页

作者：姜万润王瑞任雪光张志远李丹慧王志刚 Institute of Atomic and molecular Physics Jilin UniversityChangchun 130012China School of Science Xi'an Jiaotong UniversityXi'an 710049China

Dynamic nature of hydrogen bond (H-bond) is central in molecular science of substance transportation, energy transfer, and phase transition in H-bonding networks diversely expressed as solution, crystal, and interfacial systems, thus attracting the state-of-the-art revealing of its phenomenological edges and sophisticated causes. However, the current understanding of the ground-state fluctuation from zero-point vibration (ZPV) lacks a firm quasi-classical base, concerning three basic dimensions as geometry, electronic structure, and interaction energy. Here, based on the ab initio molecular dynamics simulation of a ground-state water dimer, temporally separated fluctuation features in the elementary H-bond as the long-time weakening and the minor short-time strengthening are respectively assigned to two low-frequency intermolecular ZPV modes and two O–H stretching ones. Geometrically, the former modes instantaneously lengthen H-bond up to 0.2 Å whose time-averaged effect coverages to about 0.03 Å over 1-picosecond. Electronic-structure fluctuation crosses criteria' borders, dividing into partially covalent and noncovalent H-bonding established for equilibrium models, with a 370% amplitude and the district trend in interaction energy fluctuation compared with conventional dragging models using frozen monomers. Extended physical picture within the normal-mode disclosure further approaches to the dynamic nature of H-bond and better supports the upper-building explorations towards ultrafast and mode-specific manipulation.

关键词： zero-point vibration hydrogen bond normal mode ab initio molecular dynamics

Local atomic structure evolution of liquid gadolinium and yttrium during solidification:An ab initio study

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Journal of Rare Earths 2023年第8期41卷 1265-1271,I0006页

作者： Qinghe Zheng Tao Hu Sébastien Le Roux Musen Li Chaoyue Chen Jianbo Yu Jiang Wang Wei Ren Zhongming Ren State Key Laboratory of Advanced Special Steels School of Materials Science and EngineeringDepartment of PhysicsInternational Center of Quantum and Molecular StructuresShanghai UniversityShanghai200444China University of Strasbourg Institut de Physique et Chimie des Matériaux de StrasbourgCNRSUMR 750423 rue du LoessStrasbourgF-67034France

Local atomic structure evolution of pure gadolinium(Gd)and yttrium(Y)during solidification was investigated by using ab initio molecular dynamics(AIMD)*** calculated results indicate that the local short-range order(SRO)in liquid Gd and Y is similar to some transitional metals with an asymmetric shape of the second peak in static structure ***,the formation of icosahedral local motifs as a function of temperature decreases the diffusivity,which explains the connection between structure evolution and dynamic *** examining the topological structures of both systems,we demonstrate that small atomic displacement leads to two different types of topological sixfold rings in liquid and solid *** analyses yield a systematic study about rare earth metals Gd and Y at the atomic level.

关键词： Atomic structure evolution Rare earth ab initio molecular dynamics Solidification

How water molecules occupying the active site of a single-atom catalyst affect the electrochemical reduction of carbon dioxide

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Nano Research 2023年第7期16卷 9091-9098页

作者： Jia Zhao Di Liu Fenfei Wei Weng Fai Ip Hui Pan Sen Lin State Key Laboratory of Photocatalysis on Energy and Environment College of ChemistryFuzhou UniversityFuzhou 350002China Institute of Applied Physics and Materials Engineering University of MacaoTaipa 999078MacaoChina Department of Physics and Chemistry Faculty of Science and TechnologyUniversity of MacaoTaipa 999078MacaoChina

In single-atom catalysts(SACs),the single atoms are often exposed as protrusions above the *** solvent molecules in the electrocatalytic environment can interact or even bind to these coordination-unsaturated single atoms and thus influence the reaction process,but this has not been studied in *** this work,we systematically investigate the thermodynamics of CO_(2)reduction reaction(CO_(2)RR)to CO over MoS_(2)-supported single metal atom catalysts(TM@MoS_(2),TM=transition metal)under vacuum and explicit solvent environments using density functional *** addition,the ab initio molecular dynamics results show that explicit H_(2)O molecules can coordinate to the TM site and undergo competitive adsorption with the CO_(2)RR intermediates,which significantly affects the energy and conformation of the CO_(2)RR *** structure analysis reveals that the occupying H_(2)O molecules change the electronic state of single atom and further influence the adsorption strength of different CO_(2)RR *** work shows that water molecules can not only act as ligands to influence the electronic state of TM,but also affect the energy and conformation of CO_(2)RR intermediates,which highlights the important role of occupying H_(2)O molecules at the single-atom sites in CO_(2)RR and provides useful insights for the design of SACs for efficient CO_(2)RR.

关键词： electrocatalytic CO_(2)reduction solvent effect single-atom catalysis density functional theory ab initio molecular dynamics

Static and dynamic evolution of CO adsorption onγ-U(100)surface with different levels of Mo doping using DFT and AIMD calculations

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Nuclear Science and Techniques 2023年第9期34卷 142-154页

作者： Jun-Wei Li Wei-Min Jia Chong Liu Sha-Sha Lv Jin-Tao Wang Zheng-Cao Li Key Lab of Advanced Materials(MOE) School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China Xi’an Research Institute of High-Technology Xi’an 710025China Key Laboratory of Beam Technology(MOE) College of Nuclear Science and TechnologyBeijing Normal UniversityBeijing 100875China

Alloys of uranium and molybdenum are considered as the future of nuclear fuel and defense ***,surface corrosion is a fundamental problem in practical applications and *** this study,the static and dynamic evolution of carbon monoxide(CO)adsorption and dissociation onγ-U(100)surface with different Mo doping levels was investigated based on density functional theory and ab initio molecular *** the static calculation phase,parameters,such as adsorption energy,configuration,and Bader charge,were evaluated at all adsorption ***,the time-dependent behavior of CO molecule adsorption were investigated at the most favorable *** minimum energy paths for CO molecu-lar dissociation and atom migration were investigated using the transition state search *** results demonstrated that the CO on the uranium surface mainly manifests as chemical adsorption before dissociation of the CO *** CO molecule exhibited a tendency to rotate and tilt upright ***,it is difficult for CO adsorption on the surface in one of the configurations with CO molecule in vertical direction but oxygen(O)is closer to the *** charge illustrates that the charge transfers from slab atoms to the 2π*antibonding orbital of CO molecule and particularly occurs in carbon(C)*** time is less than 100 fs for the adsorptions that forms embryos with tilt upright in dynamics *** density of states elucidates that the overlapping hybridization of C and O 2p orbitals is mainly formed via the d orbitals of uranium and molybdenum(Mo)atoms in the dissociation and re-adsorption of CO *** conclusion,Mo doping of the surface can decelerate the adsorption and dissociation of CO molecules.A Mo-doped surface,created through ion injection,enhanced the resistance to uranium-induced surface corrosion.

关键词： Adsorption and dissociation Uranium CO molecule Density functional theory ab initio molecular dynamics

molecular understanding of cation effects on double layers and their significance to CO-CO dimerization

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National Science Review 2023年第9期10卷 125-135页

作者： Jia-Bo Le Ao Chen Yongbo Kuang Jun Cheng Key Laboratory of Advanced Fuel Cells and Electrolyzers Technology of Zhejiang Province Ningbo Institute of Materials Technology and EngineeringChinese Academy of Sciences State Key Laboratory of Physical Chemistry of Solid Surfaces iChEM College of Chemistry and Chemical EngineeringXiamen University Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province(IKKEM)

Cation effects have been shown in numerous experiments to play a significant role in electro *** understand these effects at the molecular level,we systematically investigate the structures and capacitances of electric double layers with a variety of cations as counter charges at Pt(111)-COad/water interfaces with ab initio molecular *** is encouraging to find that the computed Helmholtz capacitances for different cations are in quantitative agreement with experiments,and that the trend of cation effects on capacitances shows clear correlation with the structures of interface cations of differing sizes and hydration *** importantly,we demonstrate the Helmholtz capacitance as the key descriptor for measuring the activity of CO-CO dimerization,the rate-determining step for C2+formation in electroreduction of CO and *** work provides atomistic insights into cation effects on electric double layers and electrocatalysis that are crucial for optimizing electrode and electrolyte materials.

关键词： cation effect electrocatalysis electric double layer CO-CO dimerization ab initio molecular dynamics