Molecular Dynamics Simulation of the Sputtering of Graphite due to Bombardment With Deuterium and Tritium in Fusion Environment

2017 ◽  
Author(s):  
Qiang Zhao ◽  
Yang Li ◽  
Zheng Zhang ◽  
Xiaoping Ouyang
Keyword(s):  
Molecular Dynamics ◽  
Temperature Increase ◽  
Incident Energy ◽  
Dynamics Simulation ◽  
Critical Issues ◽  
Calculation Results ◽  
Hydrogen Deuterium ◽  
Sputtering Yield ◽  
Dynamics Method ◽  
Lower Carbon

The sputtering of graphite due to the bombardment of hydrogen isotopes is one of the critical issues in successfully using graphite in the fusion environment. In this work, we use molecular dynamics method to simulate the sputtering by using the LAMMPS. Calculation results show that the peak values of the sputtering yield are located between 25 eV to 50 eV. After the energy of 25 eV, the higher incident energy cause the lower carbon sputtering yield. The temperature which is most likely to sputter is about 800 K for hydrogen, deuterium and tritium. Before the 800 K, the sputtering rates increase when the temperature increase. After the 800 K, they decrease with the temperature increase. Under the same temperature and energy, the sputtering rate of tritium is bigger than that of deuterium, the sputtering rate of deuterium is bigger than that of hydrogen.

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.

Molecular Dynamics Simulation of Microcrack Healing in Copper Nano-Plate

2012 ◽  
Vol 531-532 ◽  
pp. 454-457
Author(s):  
Mei Fen Wang ◽  
Guo Jun Du ◽  
Dong Yu Xia
Keyword(s):  
Molecular Dynamics ◽  
Critical Temperature ◽  
Molecular Dynamics Simulation ◽  
Temperature Increase ◽  
Healing Time ◽  
Dynamics Simulation ◽  
Crack Healing ◽  
Slip Bands ◽  
Round Shape ◽  
Dynamics Method

The molecular dynamics method is used to simulate microcrack healing in copper nano-plate during heating. During microcrack healing, the tip of microcrack is blunted and deforms to round shape, the microcrack becomes smaller and smaller until it is healed through slip bands emitting from the pre-crack tip and expanding to the top and bottom of the copper nano-plate. The healing time is different in different temperature. The healing processes in different temperature present different slip bands for crack healing. When temperature is below 650K, the healing time decreases dramatically with temperature increase. When temperature is above 650K, the healing time decreases smoothly with temperature increase. The critical temperature of microcrack healing in copper nano-plate without pre-existing dislocations is about 400K.

Cooling rate dependence of solidification for liquid aluminium: a large-scale molecular dynamics simulation study

2016 ◽  
Vol 18 (26) ◽  
pp. 17461-17469 ◽  
Author(s):  
Z. Y. Hou ◽  
K. J. Dong ◽  
Z. A. Tian ◽  
R. S. Liu ◽  
Z. Wang ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Cooling Rate ◽  
Simulation Study ◽  
Large Scale ◽  
Solidification Process ◽  
Molecular Dynamics Method ◽  
Dynamics Simulation ◽  
Liquid Aluminium ◽  
Dynamics Method

The effect of the cooling rate on the solidification process of liquid aluminium is studied using a large-scale molecular dynamics method.

scholarly journals A Molecular Dynamics Simulation of the Tensile Behavior of Y-Branched-CNT/SiC Nanocomposite

2019 ◽  
Vol 804 ◽  
pp. 7-10
Author(s):  
Guo Bin Zheng ◽  
Hideaki Sano ◽  
Osamu Nakagoe ◽  
Shuji Tanabe
Keyword(s):  
Molecular Dynamics ◽  
Simulation Method ◽  
Ceramic Materials ◽  
Nanocomposite Materials ◽  
Dynamics Simulation ◽  
Uniaxial Tensile ◽  
Direct Knowledge ◽  
Uniaxial Tensile Stress ◽  
Dynamics Method ◽  
Insight Into

The purpose of incorporating CNTs into ceramic materials is to enhance the toughness of ceramic materials, in which the interface plays a key role. Due to the nanoscale of nanocomposites, however, it is not easy to acquire a direct knowledge of the interface behavior. In this research, we simulated the dynamics of CNT/SiC and branched CNT/SiC under uniaxial tensile stress using molecular dynamics method (LAMMPS). The simulation method using molecular dynamics provide an insight into designing an effectively toughened ceramic nanocomposite materials.

The Nano-Cutting Mechanism Research of Polysilicon Based on Molecular Dynamics

2013 ◽  
Vol 690-693 ◽  
pp. 2559-2562
Author(s):  
Ying Zhu ◽  
Shun He Qi ◽  
Zhi Xiang ◽  
Ling Ling Xie
Keyword(s):  
Molecular Dynamics ◽  
Potential Energy ◽  
Cutting Force ◽  
Cutting Process ◽  
Dynamics Simulation ◽  
Cutting Mechanism ◽  
Nanometric Cutting ◽  
Mechanism Research ◽  
Atom Position ◽  
Dynamics Method

Molecular dynamics model of the polysilicon material under the micro/nanoscale is established by using molecular dynamics method, make variety of the typical defects distribute to the polysilicon model reasonable and relax the simulation model, obtain the system potential energy curves in the relaxation process and the atomic location figure after the relaxation. Conduct molecular dynamics simulation of nanometric cutting process relying on the development of simulation program, get instant atom position image and draw the cutting force curve. Discusses the typical defects impact on the polycrystalline silicon nanometric cutting process, those mainly include cutting force changes in the cutting process, potential energy changes and processed surface quality etc.

Effect of Temperature on Rheology and Nanoparticle Movements of Water Based Nanofluids by Molecular Dynamics Simulation

2016 ◽  
Author(s):  
Wenzheng Cui ◽  
Zhaojie Shen ◽  
Jianguo Yang ◽  
Shaohua Wu
Keyword(s):  
Heat Transfer ◽  
Molecular Dynamics ◽  
Cooling System ◽  
Combustion Engine ◽  
Dynamics Simulation ◽  
Effect Of Temperature ◽  
Water Based ◽  
Apparent Reason ◽  
Transfer Properties ◽  
Dynamics Method

Employing nanofluids is an innovative way to enhance heat transfer in cooling system of internal combustion engine. the reasons for the significantly enhanced heat transfer properties of nanofluids are various. On one hand, the markedly increased thermal conductivity is the most apparent reason; on the other hand, the changed rheology properties of base fluid due to the disordered movements of countless nanoparticles is even more important. Because the size scale of nanoparticles is too small, in some cases of computational simulations nanofluids is simplified as single-phase fluids. However, the influence of nanoparticles for flow behaviors of base fluids distinctly should not be ignored. By means of molecular dynamics method, a nano-scale simulation on the rheology of nanofluids could be conducted, therefore the movements of nanoparticles could be directly observed, which is conducive to reveal the influence of movements of nanoparticles for rheology of nanofluids. The present work is intended to perform a molecular dynamic simulation on the rheology of water based nanofluids. By applying temperature difference, the velocity and temperature distribution of fluid zone are calculated to evaluate heat transfer through nanofluids. Moreover, the influence of temperature for the movements of nanoparticle is discussed.

Investigation on Structures of Aluminum Melts Containing Small Amount of Silicon Element

2016 ◽  
Vol 850 ◽  
pp. 271-280
Author(s):  
Xin Yu Lv ◽  
Jun Wang ◽  
Da Shu ◽  
Bao De Sun
Keyword(s):  
Molecular Dynamics ◽  
Simulation Method ◽  
Dynamics Simulation ◽  
Silicon Concentration ◽  
Structure Stability ◽  
Aluminum Melt ◽  
Melt Structures ◽  
And Diffusion ◽  
Silicon Silicon ◽  
Dynamics Method

Aluminum melt structures play significant roles in process of impurity element eliminations. In order to investigate the aluminum melt structures containing small amount of silicon element, several compositions of aluminum melts were simulated. Molecular dynamics simulation method was employed to investigate the melt structures, concentration profiles and diffusion properties. For purpose of studying structure stability, related calculations were performed by first principles molecular dynamics method. The calculated results suggest that silicon concentration has obvious influence on silicon-silicon radial distribution function; silicon element segregates in local zone in each concentration of aluminum; there is no obvious relationship between silicon concentration and silicon diffusion coefficient; the stable Al-Si phase is formed by substitution lattice point or interstitial space; and position of Fermi energy of the stable structure corresponds to the valley of density of states.

Multi-nanoparticle model simulations of the porosity effect on sintering processes in Ni/YSZ and Ni/ScSZ by the molecular dynamics method

2015 ◽  
Vol 3 (43) ◽  
pp. 21518-21527 ◽  
Author(s):  
Jingxiang Xu ◽  
Shandan Bai ◽  
Yuji Higuchi ◽  
Nobuki Ozawa ◽  
Kazuhisa Sato ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Simulation Method ◽  
Molecular Dynamics Method ◽  
Dynamics Simulation ◽  
Model Simulations ◽  
Porosity Effect ◽  
Sintering Processes ◽  
Dynamics Method

The effects of the ceramic type and porosity on the sintering and degradation in Ni/YSZ and Ni/ScSZ anodes are unveiled by a recently developed multi-nanoparticle sintering simulation method based on molecular dynamics simulation.

scholarly journals A Study on Sputtering of Copper Seed Layer for Interconnect Metallization via Molecular Dynamics Simulation

2021 ◽  
Vol 11 (20) ◽  
pp. 9702
Author(s):  
Cheng-Hsuan Ho ◽  
Cha’o-Kuang Chen ◽  
Chieh-Li Chen
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Substrate Temperature ◽  
Deposition Rate ◽  
Process Parameters ◽  
Seed Layer ◽  
Incident Energy ◽  
Incident Angle ◽  
Dynamics Simulation ◽  
Copper Seed Layer

Interconnects are significant elements in integrated circuits (ICs), as they connect individual components of the circuit into a functioning whole. To form a void-free interconnect, a thin and uniform copper seed layer must be deposited as a basis for electroplating. In this paper, process parameters of sputtering including incident energy, incident angle, substrate temperature, and deposition rate were studied to form a uniform copper seed layer. Different liner/barrier materials and properties including crystal planes were also studied to enhance the quality of the copper seed layer. The study was carried out by molecular dynamics simulation. It revealed that increasing the incident energy and substrate temperature during the sputtering process increases their diffusivity but results in poorer uniformity and larger alloy percentage. By decreasing the deposition rate, the Ostwald ripening effect becomes dominant and increases the uniformity. An adequate incident angle could increase necking and uniformity. Among the sputtering process parameters and material properties discussed in this study, surface diffusion barrier energy of different crystal planes is the most decisive factor, which leads to good uniformity.

scholarly journals Cluster Evolution in Thermal Decomposition of CL-20/TNT Co-Crystal in Compressed State:A ReaxFF Reactive Molecular Dynamics Simulation Study

2021 ◽  
Author(s):  
Yan Li ◽  
Wen-li Yu ◽  
Huang Huang ◽  
Min Zhu
Keyword(s):  
Molecular Dynamics ◽  
Thermal Decomposition ◽  
Atmospheric Pressure ◽  
Product Formation ◽  
Decomposition Process ◽  
Dynamics Simulation ◽  
Thermal Decomposition Process ◽  
Reactive Molecular Dynamics ◽  
Cluster Evolution ◽  
Dynamics Method

Abstract The thermal decomposition process of CL-20/TNT co-crystal in different compression states is simulated by ReaxFF reactive molecular dynamics method. Co-crystals models with different degrees of compression are obtained under four pressures of atmospheric pressure, 4.6GPa, 9.2GPa and 18.4GPa. The potential energy evolution, product formation and cluster evolution in the process are analyzed. We find that the formation of clusters is the key to the decomposition process. When the system is compressed, there will be more clusters which can bind the free atoms, resulting in the reaction to be inhibited. Other evolution information conforms this.

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