scholarly journals Analysis of Pd-Ni Nanobelts Melting Process Using Molecular Dynamics Simulation

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Chen Gang ◽  
Zhang Peng ◽  
Liu HongWei
Keyword(s):  
Md Simulation ◽  
Melting Process ◽  
Pure Metal ◽  
Dynamics Simulation ◽  
Analysis Method ◽  
Melting Points ◽  
Index Pair ◽  
Ni Alloy ◽  
Increasing Temperature ◽  
Pair Analysis

The melting process of Pd-Ni alloy nanobelts with different Ni atom content has been simulated by molecular dynamic (MD) method. The radial distribution function, the Lindemann index, and pair analysis method were used to characterize Pd-Ni nanobelt models in simulation. The results indicate that the melting temperature of Pd-Ni nanobelt with composition far from pure metal was lower than that of other models, and the breaking point of the nanobelt can be illustrated by the Lindemann index. Pair analysis indicates that the number of FCC pairs will decrease and almost disappear at melting point with increasing temperature. The melting points of Pd-Ni alloy nanobelts were also calculated by thermodynamic method, and the results were close to that obtained by MD simulation.

Molecular dynamics simulation of the coalescence and melting process of Au and Cu nano-clusters

2018 ◽  
Vol 32 (06) ◽  
pp. 1850061
Author(s):  
Gang Chen ◽  
Chuan Jie Wang ◽  
Peng Zhang
Keyword(s):  
Shear Deformation ◽  
Melting Process ◽  
Dynamics Simulation ◽  
Particle Rotation ◽  
Interface Diffusion ◽  
Surface And Interface ◽  
Simulation Procedure ◽  
Increasing Temperature ◽  
Deformation Surface ◽  
Cu Nanoclusters

Molecular dynamic (MD) method is used to study the coalescence and fusing process of Au and Cu nanoclusters. The results show that shear deformation, surface and interface diffusion play important role in different stages of all simulation procedure. In most cases, shear deformation produces the twin boundary or/and stacking fault in particles by particle rotation and slide. The angle between the {111} of Au and Cu particles decrease with increasing temperature, which promotes the formation of the stable interface. Furthermore, the coalescence point and melting temperature increase as cluster diameter increases. For the other cases, there are no particle rotation and slide phenomenon in the elevating temperature process because the stable interface can be formed by forming twin boundaries once two particles contact.

PHASE CHANGES IN ICOSAHEDRAL 54-, 55-, 56-ATOM PLATINUM CLUSTERS

2004 ◽  
Vol 15 (07) ◽  
pp. 981-988 ◽  
Author(s):  
ALI SEBETCI ◽  
ZIYA B. GÜVENÇ ◽  
HATICE KÖKTEN
Keyword(s):  
Global Minimum ◽  
Melting Process ◽  
Melting Behavior ◽  
Phase Changes ◽  
Dynamics Simulation ◽  
Analysis Method ◽  
Embedded Atom ◽  
Platinum Clusters ◽  
Specific Temperature ◽  
Physical Quantities

Using the Voter and Chen version of an embedded-atom model, derived by fitting simultaneously to experimental data both the diatomic molecule and bulk platinum, we have studied the melting behavior of free, icosahedral, 54-, 55- and 56-atom platinum clusters in the molecular dynamics simulation technique. We present an atom-resolved analysis method that includes physical quantities such as the root-mean-square bond-length fluctuation and coordination number for individual atoms as functions of temperature. The effect of a central atom in the icosahedral structure to the melting process is discussed. The results show that the global minimum structures of the 54-, 55- and 56-atom Pt clusters do not melt at a specific temperature, rather, melting processes take place over a finite temperature range. The heat capacity peaks are not δ-functions, but instead remain finite. An ensemble of clusters in the melting region is a mixture of solid-like and liquid-like clusters.

Study of Helium Bubble Induced Hardening in BCC-Fe by Molecular Dynamics Simulation

2019 ◽  
Vol 944 ◽  
pp. 378-386
Author(s):  
Li Xia Jia ◽  
Xin Fu He ◽  
Shi Wu ◽  
Dong Jie Wang ◽  
Han Cao ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Edge Dislocation ◽  
Reasonable Agreement ◽  
Md Simulation ◽  
Md Simulations ◽  
Defect Size ◽  
Dynamics Simulation ◽  
Helium Bubble ◽  
Increasing Temperature ◽  
Critical Resolved Shear Stress

The interaction between an moving edge dislocation and helium bubble was studied in BCC-Fe using Molecular dynamics（MD）simulation. Edge dislocation passed the bubble via cut mechanism. A step with a length of b is left on both sides of the bubble after dislocation left away. The influence of simulation temperature, defect size and He/V ratio in bubble on critical resolved shear stress (CRSS) for dislocation to shear bubble were investigated. The CRSS increases with increasing defect sizes, and decreases with increasing temperature. When He/V ratio is at the range of 0-1, CRSS depends weakly on the He/V ratio. The estimated obstacle strength of helium bubble based on MD simulations is acceptable and reasonable agreement with one deduced from the dispersion barrier-hardening model applied to experimental results.

scholarly journals Molecular Dynamics Simulation of Solidification of Pd-Ni Clusters with Different Nickel Content

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Chen Gang ◽  
Zhang Peng ◽  
Liu Hongwei
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Nickel Content ◽  
Solidification Process ◽  
Amorphous Structure ◽  
Pure Metal ◽  
Dynamics Simulation ◽  
Alloy Nanoparticles ◽  
Formation Enthalpies ◽  
Ni Alloy

Molecular dynamics simulation has been performed for investigating the glass transition of Pd-Ni alloy nanoparticles in the solidification process. The results showed that the Pd-Ni nanoparticles with composition far from pure metal should form amorphous structure more easily, which is in accordance with the results of the thermodynamic calculation. There are some regular and distorted fivefold symmetry in the amorphous Pd-Ni alloy nanoparticles. The nanoclusters with bigger difference value between formation enthalpies of solutions and glasses will transform to glass more easily than the other Pd-Ni alloy nanoclusters.

Structure prediction of SPAK C-terminal domain and analysis of its binding to RFXV/I motifs by homology modelling, docking, and molecular dynamics simulation studies

2020 ◽  
Vol 16 ◽  
Author(s):  
Mubarak A. Alamri ◽  
Ahmed D. Alafnan ◽  
Obaid Afzal ◽  
Alhumaidi B. Alabbas ◽  
Safar M. Alqahtani
Keyword(s):  
Molecular Dynamic ◽  
Dynamic Stability ◽  
Md Simulation ◽  
Homology Modelling ◽  
Antihypertensive Agents ◽  
Structure And Function ◽  
Dynamics Simulation ◽  
Dimensional Structure ◽  
Terminal Domain ◽  
And Function

Background: The STE20/SPS1-related proline/alanine-rich kinase (SPAK) is a component of WNKSPAK/OSR1 signaling pathway that plays an essential role in blood pressure regulation. The function of SPAK is mediated by its highly conserved C-terminal domain (CTD) that interacts with RFXV/I motifs of upstream activators, WNK kinases, and downstream substrate, cation-chloride cotransporters. Objective: To determine and validate the three-dimensional structure of the CTD of SPAK and to study and analyze its interaction with the RFXV/I motifs. Methods: A homology model of SPAK CTD was generated and validated through multiple approaches. The model was based on utilizing the OSR1 protein kinase as a template. This model was subjected to 100 ns molecular dynamic (MD) simulation to evaluate its dynamic stability. The final equilibrated model was used to dock the RFQV-peptide derived from WNK4 into the primary pocket that was determined based on the homology sequence between human SPAK and OSR1 CTDs. The mechanism of interaction, conformational rearrangement and dynamic stability of the binding of RFQV-peptide to SPAK CTD were characterized by molecular docking and molecular dynamic simulation. Results: The MD simulation suggested that the binding of RFQV induces a large conformational change due to the distribution of salt bridge within the loop regions. These results may help in understanding the relation between the structure and function of SPAK CTD and to support drug design of potential SPAK kinase inhibitors as antihypertensive agents. Conclusion: This study provides deep insight into SPAK CTD structure and function relationship.

scholarly journals Molecular dynamics simulation of sI methane hydrate under compression and tension

2020 ◽  
Vol 18 (1) ◽  
pp. 69-76
Author(s):  
Qiang Wang ◽  
Qizhong Tang ◽  
Sen Tian
Keyword(s):  
Molecular Dynamics ◽  
Methane Hydrate ◽  
Fracture Process ◽  
Md Simulation ◽  
Maximum Stress ◽  
Dynamics Simulation ◽  
Tensile Fracture ◽  
Maximum Compressive Stress ◽  
Motion State ◽  
Stress States

AbstractMolecular dynamics (MD) analysis of methane hydrate is important for the application of methane hydrate technology. This study investigated the microstructure changes of sI methane hydrate and the laws of stress–strain evolution under the condition of compression and tension by using MD simulation. This study further explored the mechanical property and stability of sI methane hydrate under different stress states. Results showed that tensile and compressive failures produced an obvious size effect under a certain condition. At low temperature and high pressure, most of the clathrate hydrate maintained a stable structure in the tensile fracture process, during which only a small amount of unstable methane broke the structure, thereby, presenting a free-motion state. The methane hydrate cracked when the system reached the maximum stress in the loading process, in which the maximum compressive stress is larger than the tensile stress under the same experimental condition. This study provides a basis for understanding the microscopic stress characteristics of methane hydrate.

Reaction Heat of High Alkali Aluminosilicate Glass Batches in Melting Process

2014 ◽  
Vol 852 ◽  
pp. 71-75 ◽  
Author(s):  
Ying Liang Tian ◽  
Jin Shu Cheng ◽  
Jing Zhang ◽  
Yan Li Shao ◽  
Xiao Li
Keyword(s):  
Raw Materials ◽  
Melting Process ◽  
Aluminosilicate Glass ◽  
Heating Process ◽  
Analysis Method ◽  
Optimization Scheme ◽  
Reaction Heat ◽  
Significant Difference ◽  
Carbonate Decomposition ◽  
High Alkali

High alkali aluminosilicate glass batches were prepared by five different raw materials, reaction heat of which in melting process was studied by means of DSC thermal analysis method. The results show that reaction heat of batches in the heating process of 25-1600°C exists a significant difference, and which is among 4396.38 J/g-5311.14 J/g, moreover the least is the batches using petalite, while the most is spodumene. In the whole heating process, 380-800°C is carbonate decomposition stage, which accounts for 42-46% of the total absorbed heat; and 800-1200°C is silicate reaction stage, 40-50%; and 1200-1600°C is glass clarify and homogenization phase , 6%-16%. Therefore, carbonate decomposition and silicate reaction is the main part of batches heat consumption, the optimization scheme for materials has a significant effect on energy saving and emission reduction.

Sputtering of Graphite by Hydrogen Isotopes in the Fusion Environment: A Molecular Dynamics Simulation Study

2018 ◽  
Vol 4 (4) ◽  
Author(s):  
Qiang Zhao ◽  
Yang Li ◽  
Zheng Zhang ◽  
Xiaoping Ouyang
Keyword(s):  
Molecular Dynamics ◽  
Incident Energy ◽  
Large Scale ◽  
Incident Angle ◽  
Hydrogen Isotopes ◽  
Dynamics Simulation ◽  
Calculation Results ◽  
Sputtering Yield ◽  
Increasing Temperature ◽  
Sputtering Yields

The sputtering of graphite due to the bombardment of hydrogen isotopes is crucial to successfully using graphite in the fusion environment. In this work, we use molecular dynamics to simulate the sputtering using the large-scale atomic/molecular massively parallel simulator (lammps). The calculation results show that the peak values of the sputtering yield are between 25 eV and 50 eV. When the incident energy is greater than the energy corresponding to the peak value, a lower carbon sputtering yield is obtained. The temperature that is most likely to sputter is approximately 800 K for hydrogen, deuterium, and tritium. Below the 800 K, the sputtering yields increase with temperature. By contrast, above the 800 K, the yields decrease with increasing temperature. Under the same temperature and incident energy, the sputtering rate of tritium is greater than that of deuterium, which in turn is greater than that of hydrogen. When the incident energy is 25 eV, the sputtering yield at 300 K increases below an incident angle at 30 deg and remains steady after that.

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