Molecular dynamics simulation of the impact behaviour of various hydrocarbon species on DLC

Author(s):  
E. Neyts ◽  
A. Bogaerts ◽  
R. Gijbels ◽  
J. Benedikta ◽  
M.C.M. van de Sanden
2012 ◽  
Vol 500 ◽  
pp. 696-701
Author(s):  
Ying Zhu ◽  
Sen Song ◽  
Ling Ling Xie ◽  
Shun He Qi ◽  
Qian Qian Liu

This method of parallel computing into nanoindentation molecular dynamics simulation (MDS), the author uses a nine-node parallel computer and takes the single crystal aluminum as the experimental example, to implement the large-scale process simulation of nanoindentation. Compared the simulation results with experimental results is to verify the reliability of the simulation. The method improves the computational efficiency and shortens the simulation time and the expansion of scale simulation can significantly reduce the impact of boundary conditions, effectively improve the accuracy of the molecular dynamics simulation of nanoindentation.


Minerals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 162 ◽  
Author(s):  
Qiu ◽  
Liu ◽  
Jiang ◽  
Chen ◽  
Wang ◽  
...  

At monolayer hydration state, the spatial distribution of H2O and Na+ in the interlayer of Na-montmorillonite (Na-MT) with different crystal chemistry properties was investigated by the molecular dynamics simulation method. The simulation results show that when layer charge density increases, H2O will move and form hydrogen bonds with O in tetrahedral surfaces (Ot) at a distance of 1.676 ± 0.043 Å. The impact of isomorphic substitution on the relative concentration of H2O depends largely on the layer charge density of Na-MT, when layer charge density is high, H2O move obviously to both sides of Na-MT sheets with the increase of octahedral substitution ratio. Nevertheless, Na+ coordinate with Ot at a distance of 2.38 Å, and the effect of isomorphic substitution ratio on the diffusion of Na+ is opposite to that of H2O. The mobility of both H2O and Na+ decreases with the increase of layer charge density or tetrahedral substitution ratio. The radial distribution function of Na-Ow (O in H2O) shows that the coordination strength between Na+ and Ow decreases with the increase of layer charge density or tetrahedral substitution ratio, and Na+ are hydrated by four H2O at a Van der Waals radius of 2.386 ± 0.004 Å. The research results can provide a theoretical basis for the efficient application of Na-MT at the molecular and atomic levels.


Biopolymers ◽  
2015 ◽  
Vol 104 (6) ◽  
pp. 703-706 ◽  
Author(s):  
Stephan Niebling ◽  
Emma Danelius ◽  
Ulrika Brath ◽  
Sebastian Westenhoff ◽  
Máté Erdélyi

2002 ◽  
Vol 16 (26) ◽  
pp. 3971-3978 ◽  
Author(s):  
A. J. DU ◽  
Z. Y. PAN ◽  
Z. HUANG ◽  
Z. J. LI ◽  
Q. WEI ◽  
...  

In this paper, the initial stage of films assembled by energetic C 36 fullerenes on diamond (001)–(2 × 1) surface at low-temperature was investigated by molecular dynamics simulation using the Brenner potential. The incident energy was first uniformly distributed within an energy interval 20–50 eV, which was known to be the optimum energy range for chemisorption of single C 36 on diamond (001) surface. More than one hundred C 36 cages were impacted one after the other onto the diamond surface by randomly selecting their orientation as well as the impact position relative to the surface. The growth of films was found to be in three-dimensional island mode, where the deposited C 36 acted as building blocks. The study of film morphology shows that it retains the structure of a free C 36 cage, which is consistent with Low Energy Cluster Beam Deposition (LECBD) experiments. The adlayer is composed of many C 36-monomers as well as the covalently bonded C 36 dimers and trimers which is quite different from that of C 20 fullerene-assembled film, where a big polymerlike chain was observed due to the stronger interaction between C 20 cages. In addition, the chemisorption probability of C 36 fullerenes is decreased with increasing coverage because the interaction between these clusters is weaker than that between the cluster and the surface. When the incident energy is increased to 40–65 eV, the chemisorption probability is found to increased and more dimers and trimers as well as polymerlike- C 36 were observed on the deposited films. Furthermore, C 36 film also showed high thermal stability even when the temperature was raised to 1500 K.


Author(s):  
Beibei Zhu ◽  
Hongtao Gao

In order to investigate the effect of n-decanol, a kind of alcohol surfactants, on the absorption of water vapor into lithium bromide aqueous solution, this study focused on microscopic structure of the liquid-vapor interface of the electrolyte solution, the impact of n-decanol molecules on the interfacial properties and the absorption dynamic process employing the method of molecular dynamics simulation. The liquid-vapor configuration of lithium bromide aqueous solution added with four concentration of n-decanol can be analyzed by examining the density profile, the radial distribution functions and orientational order parameter. The computed results revealed that n-decanol molecules tended to adsorb at the interface with the methyl group pointing into the vapor phase and hydrophilic hydroxyl group pointing into the liquid phase which do much help to form a hydrogen bond network with water, and the tendency of this kind of preferred orientation became distinct with the increase of the amount of n-decanol. The hydrocarbon chains of n-decanol molecules were inclined to close to stay upright near the interface while the monolayer of n-decanol came into being near the interface. Ions were repelled from the surface. The direct interactions between hydroxyl hydrogen of n-decanol and anion exist, and there are much stronger electrostatic interactions between oxygen of n-decanol and cation. The dynamic process of the absorption of water into aqueous electrolyte solution with or without n-decanol was explored by molecular dynamics simulation under non equilibrium conditions. The simulation results showed that in comparison to the lithium bromide aqueous solution without n-decanol, the electrolyte aqueous solution with n-decanol can absorb more water molecules distinctly for 100 ps.


Author(s):  
Hong Gao ◽  
Liangju Zhao ◽  
Danling Zeng ◽  
Lijuan Gao

Cold gas spray is a relatively new coating technique by which coatings can be formed without significant heating of the sprayed powder. In contrast to the conventional thermal spray processes, such as flame, arc, and plasma spraying, in cold spraying there is no melting of particles prior to impact on the substrate. In cold spray, particles are accelerated to a very high velocity by a flowing gas with supersonic speed and the temperature of spray particles is much lower than its melting point. However, being accomplished in so short an interval, the impact and deposition processes are difficult to be observed by experimental ways. Using molecular dynamics simulation, the deposition of nano-scale Au clusters on Au (001) surface was studied. The many-body potential is used to simulate the interatomic force between the atoms. By taking “snapshot”, the impact, deposition process and the final appearances of the cluster and the substrate were observed directly. It is found that both the substrate and the cluster deform and lose the crystalline structure. But after reconstruction and relaxation, both of them recover the crystalline structure. By calculating the temperatures of the substrate and the local area influenced by impinging, it is found that the melt phenomenon occurs during impact and deposition, whereas the temperature of the rest region of the substrate is still below the melt point. In addition, the influence factors on deposition, such as incident velocity and the size of the cluster, are discussed in the paper. Simulation results show that the higher incident velocity or the larger size of the cluster could result in stronger interaction between the substrate and the cluster owing to the higher kinetic energy of the cluster.


2021 ◽  
pp. 115914
Author(s):  
Reza Yekta ◽  
Leila Sadeghi ◽  
Sohrab Ahmadi-Kandjani ◽  
Pouriya Naziri ◽  
Mohammad-Reza Rashidi ◽  
...  

2021 ◽  
Author(s):  
Mehran Vaezi ◽  
Ahmad Movahedpour ◽  
Mortaza Taheri-Anganeh ◽  
Mehrdad Ameri

Abstract We investigated the encapsulation of small interfering RNA (siRNA) in carbon nanotube (CNT) using molecular dynamics simulation. siRNAs can be used to silence specific genes effectively if they remain intact while they are delivered to their target cells. Along with the various drug delivery systems designed for this purpose, CNTs are a promising one. Based on their shape, siRNA can encapsulate inside CNTs and protect them from degradation. However, several factors can affect siRNA encapsulation inside CNTs including temperature and CNT diameter. Herein, we conducted a simulation study to evaluate the impact of these factors in the placement of siRNA. Our results can be considered in designing further experimental siRNA delivery systems using carbon nanotubes.


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