scholarly journals The Structure and Crystallizing Process of NiAu Alloy: A Molecular Dynamics Simulation Method

2021 ◽  
Vol 5 (1) ◽  
pp. 18
Author(s):  
Dung Nguyen Trong ◽  
Van Cao Long ◽  
Ştefan Ţălu
Keyword(s):  
Heating Rate ◽  
Atomic Number ◽  
Crystallization Process ◽  
Amorphous State ◽  
Simulation Method ◽  
Dynamics Simulation ◽  
Glass Temperature ◽  
Structural Units ◽  
The Common ◽  
Moving Process

This paper studies the influence of factors such as heating rate, atomic number, temperature, and annealing time on the structure and the crystallization process of NiAu alloy. Increasing the heating rate leads to the moving process from the crystalline state to the amorphous state; increasing the temperature (T) also leads to a changing process into the liquid state; when the atomic number (N), and t increase, it leads to an increased crystalline process. As a result, the dependence between size (l) and atomic number (N), the total energy of the system (Etot) with N as l~N−1/3, and −Etot always creates a linear function of N, glass temperature (Tg) of the NiAu alloy, which is Tg = 600 K. During the study, the number of the structural units was determined by the Common Neighborhood Analysis (CNA) method, radial distribution function (RDF), size (l), and Etot. The result shows that the influencing factors to the structure of NiAu alloy are considerable.

Effect of heating rate, impurity concentration of Cu, atomic number, temperatures, time annealing temperature on the structure, crystallization temperature and crystallization process of Ni1−xCux bulk; x = 0.1, 0.3, 0.5, 0.7

2018 ◽  
Vol 32 (26) ◽  
pp. 1830009 ◽  
Author(s):  
Tran Quoc Tuan ◽  
Nguyen Trong Dung
Keyword(s):  
Heating Rate ◽  
Crystallization Temperature ◽  
Impurity Concentration ◽  
Crystallization Process ◽  
Annealing Temperature ◽  
Structural Characteristics ◽  
Amorphous State ◽  
Atom Number ◽  
Structure Unit ◽  
Temperature Crystallization

This paper studies the effects of heating rate 4 × 10[Formula: see text] K/s, 4 × 10[Formula: see text] K/s, 4 × 10[Formula: see text] K/s; impurity concentration of Cu on Ni[Formula: see text]Cu[Formula: see text] bulk with x = 0.1, x = 0.3, x = 0.5, x = 0.7; atom number (N), N = 4000 atoms, 5324 atoms, 6912 atoms, 8788 atoms at temperatures (T), T = 300 K; N = 6912 atoms at T = 300 K, 400 K, 500 K, 600 K, 700 K, 800 K; N = 6912 atoms at T = 600 K after time annealing temperature (t), t = 500 ps on the structure, crystallization temperature and crystallization process of Ni[Formula: see text]Cu[Formula: see text] bulk by molecular dynamics (MD) method with interactive embedding Sutton–Chen (ST) and periodic boundary conditions. The structural characteristics were analyzed through radial distribution function (RDF), energy total (E[Formula: see text]), size (l) and common neighborhood analysis (CNA) method; temperature (T), crystallization temperature (T[Formula: see text]), crystallization process through relationship between E[Formula: see text], T. The results showed Ni[Formula: see text]Cu[Formula: see text] bulk and links Ni–Ni, Ni–Cu, Cu–Cu always exist in 03 types structures: FCC, HCP, Amor. When time annealing temperature increases then Ni[Formula: see text]Cu[Formula: see text] bulk moves from a crystalline state to an amorphous state. When increases impurity concentration of Cu in Ni[Formula: see text]Cu[Formula: see text] bulk, then the structure unit number FCC, HCP decreases and then increases, structure unit number Amor increases and then decreases. When atom number (N) increases, decreasing T and increasing time annealing temperature lead to structure unit number FCC, HCP increases, Amor decreases and structural, crystallization temperature, crystallization process of Ni[Formula: see text]Cu[Formula: see text] bulk change.

scholarly journals Molecular Dynamics Simulation of Mechanical Deformation of Ultra-Thin Metal and Ceramic Films

1995 ◽  
Vol 389 ◽  
Author(s):  
J. Belak ◽  
J.N. Glosli ◽  
D.B. Boercker ◽  
I.F. Stowers
Keyword(s):  
Molecular Dynamics ◽  
Orthogonal Cutting ◽  
Amorphous State ◽  
Computer Experiment ◽  
Shear Plane ◽  
Simulation Method ◽  
Dynamics Simulation ◽  
Interesting Phenomenon ◽  
Entire Volume ◽  
Embedded Atom

ABSTRACTWe present an overview of the molecular dynamics computer simulation method as employed in the study of the mechanical properties of surfaces at the nanometer scale. The embedded atom method is used to model a clean metal surface and the bond-order model is used to model ceramic surfaces. The computer experiment consists of the indentation and scraping of a hard diamond-like tool into and across the surface. Results are presented for the (111) surface of copper and silver and for the (100) surface of silicon. We explicitly demonstrate in our point indentation simulations that nanoscale plasticity in metals takes place by nondislocation mechanisms, a result suggested by recent nanoindentation experiments. We also observe the surface to accommodate nearly the entire volume of the tip and the annealing out of plastic work as the tip is removed. In our orthogonal cutting simulation, we observe an interesting phenomenon: the system dynamically reorients the grain in front of the tool tip to minimize the work performed on the shear plane (i.e. the shear plane becomes an easy slip plane). Silicon transforms into an amorphous state which then flows plastically.

Femtosecond photoelectron spectroscopy of the I2− anion: A semiclassical molecular dynamics simulation method

1999 ◽  
Vol 110 (8) ◽  
pp. 3736-3747 ◽  
Author(s):  
Victor S. Batista ◽  
Martin T. Zanni ◽  
B. Jefferys Greenblatt ◽  
Daniel M. Neumark ◽  
William H. Miller
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Photoelectron Spectroscopy ◽  
Simulation Method ◽  
Dynamics Simulation

Self-diffusion of lignite/water under different temperatures and pressure: A molecular dynamics study

2016 ◽  
Vol 30 (01) ◽  
pp. 1550253 ◽  
Author(s):  
Xinjian Liu ◽  
Yu Jin ◽  
Congliang Huang ◽  
Jingfeng He ◽  
Zhonghao Rao ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Water System ◽  
Simulation Method ◽  
The Self ◽  
Dynamics Simulation ◽  
Low Rank ◽  
Self Diffusion ◽  
Change Mechanism ◽  
Different Temperatures ◽  
Temperature And Pressure

Temperature and pressure have direct and remarkable implications for drying and dewatering effect of low rank coals such as lignite. To understand the microenergy change mechanism of lignite, the molecular dynamics simulation method was performed to study the self-diffusion of lignite/water under different temperatures and pressure. The results showed that high temperature and high pressure can promote the diffusion of lignite/water system, which facilitates the drying and dewatering of lignite. The volume and density of lignite/water system will increase and decrease with temperature increasing, respectively. Though the pressure within simulation range can make lignite density increase, the increasing pressure showed a weak impact on variation of density.

THE "FOLDING" BEHAVIORS OF HOMOPOLYMERS WITH ONE END FIXED

2004 ◽  
Vol 18 (15) ◽  
pp. 2123-2139 ◽  
Author(s):  
BIN XUE ◽  
JUN WANG ◽  
WEI WANG
Keyword(s):  
Molecular Dynamics ◽  
Chain Length ◽  
Conformational Changes ◽  
Canonical Ensemble ◽  
Interaction Strength ◽  
Simulation Method ◽  
Dynamics Simulation ◽  
Radius Of Gyration ◽  
Native Conformation ◽  
Collapse Temperature

We study the "folding" behaviors of homopolymers with one end fixed. By using canonical ensemble molecular dynamics simulation method, we observe the conformational changes during folding processes. Long chains collapse to the helical nuclei, then regroup to helix from the free-end to form the compact conformations through the middle stages of helix-like coil and helix-like cone, while short chains do not apparently have the above mentioned middle stages. Through simulated annealing, the native conformation of homopolymer chain in our model is found to be helix. We show the relations between specific heat C v (T) and radius of gyration R g (T) as functions of temperature, chain length and the interaction strength, respectively. We find that these two quantities match well and can be combined to interpret the "folding" process of the homopolymer. It is found that the collapse temperature Tθ and the native-like folding temperature T f do not change with the chain length in our model, however the interaction strength affects the values of Tθ and T f .

Molecular dynamics simulation for structural heterogeneity and diffusion process in liquid GeO2

2021 ◽  
Vol 66 (1) ◽  
pp. 42-48
Author(s):  
Kien Pham Huu ◽  
Linh Nguyen Hong ◽  
Hien Pham Xuan ◽  
Linh Nguyen Thi Thuy ◽  
Quang Phan Dinh ◽  
...  
Keyword(s):  
Diffusion Process ◽  
Length Distribution ◽  
Structural Heterogeneity ◽  
Dynamics Simulation ◽  
Angle Distribution ◽  
Structural Units ◽  
Oxide Systems ◽  
Dynamical Heterogeneity ◽  
Liquid Oxide ◽  
And Diffusion

In this paper, we perform a simulation about liquid GeO2. The structure and diffusion process are analyzed through the radial distribution function, the distribution of GeOx (x = 4, 5, 6) structural units, length distribution, angle distribution, and data visualization. Simulation results show that the structure of liquid GeO2 composes clusters of GeO4, GeO5, or GeO6. These clusters have sizes depending on pressure and are distributed heterogeneously in space. This result confirms the origin of dynamical heterogeneity in the liquid oxide systems. In addition, the diffusion coefficient of Ge and O decreases upon pressure. We show that the diffusion relates to the breaking bond Ge-O.

scholarly journals Molecular Dynamics Study on the Mechanism of Nanoscale Jet Instability Reaching Supercritical Conditions

2018 ◽  
Vol 8 (10) ◽  
pp. 1714 ◽  
Author(s):  
Qingfei Fu ◽  
Yunxiao Zhang ◽  
Chaojie Mo ◽  
Lijun Yang
Keyword(s):  
Molecular Dynamics ◽  
Growth Rate ◽  
Theoretical Result ◽  
Molecular Model ◽  
Simulation Method ◽  
Dynamics Simulation ◽  
Jet Instability ◽  
Subcritical Region ◽  
Thermodynamic Conditions ◽  
Spatio Temporal

This paper investigates the characteristics of a nitrogen jet (the thermodynamic conditions ranging from subcritical to supercritical) ejected into a supercritical nitrogen environment using the molecular dynamics (MD) simulation method. The thermodynamic properties of nitrogen obtained by molecular dynamics show good agreement with the Soave-Redlich-Kwong (SRK) equation of state (EOS). The agreement provides validation for this nitrogen molecular model. The molecular dynamics simulation of homogeneous nitrogen spray is carried out in different thermodynamic conditions from subcritical to supercritical, and a spatio-temporal evolution of the nitrogen spray is obtained. The interface of the nitrogen spray is determined at the point where the concentration of ejected fluid component reaches 50%, since the supercritical jet has no obvious vapor-liquid interface. A stability analysis of the transcritical jets shows that the disturbance growth rate of the shear layer coincides very well with the classical theoretical result at subcritical region. In the supercritical region, however, the growth rate obtained by molecular dynamics deviates from the theoretical result.

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