Molecular Dynamics Simulations to Evaluate the Effect of Applied Strain on Interstitial Cluster Formation and Orientation Under Collision Cascade Damage

Author(s):  
Satoshi Miyashiro ◽  
Satoshi Fujita ◽  
Mitsuhiro Itakura ◽  
Taira Okita

We conducted molecular dynamics (MD) simulations to analyze the strain influence on defect formation and orientation. Collision cascade damage was initiated under uniaxial applied strain with a PKA energy of 10 keV. The number of residual defects increased with applied strain because of the enhanced formation of larger defect cluster. We also applied uniaxial strain to the simulation cell which included an interstitial cluster and detected the change in its direction. The probability of a change in the defect cluster direction was significantly higher under strain. Results further showed that the probability of the change in direction is higher with smaller defect clusters, and that it is extremely low with clusters larger than a certain size.

Author(s):  
Toshihiro Horinouchi ◽  
Satoshi Miyashiro ◽  
Mitsuhiro Itakura ◽  
Taira Okita

The influence of applied strain on the defect production rate during a cascade process was evaluated for several FCC metals with different Stacking Fault Energy by the method of molecular dynamics. It was found that applied strain increases the number of surviving defects, which is caused by the enhanced formation of larger clusters. It was also found that the number of defects is almost independent of Stacking Fault Energy even under applied strain.


1999 ◽  
Vol 584 ◽  
Author(s):  
T. Motooka ◽  
S. Munetoh ◽  
K. Nisihira ◽  
K. Moriguchi ◽  
A. Shintani

AbstractWe have investigated crystal growth and defect formation processes during solid phase epitaxy (SPE) of Si in the [001] direction based on molecular dynamics (MD) simulations using the Tersoff potential. From the Arrhenius plot of the growth rates obtained by MD simulations, we have found that the activation energy of SPE at lower temperatures is in good agreement with the experimental value, approximately 2.7 eV, while it becomes lower at higher temperatures. This can be attributed to the difference in the amorphous/crystalline (a/c) interface structure. In the low temperature region, the a/c interface is essentially (001) and the rate-limiting step is two-dimensional nucleation on the (001) a/c interface. On the other hand, the a/c interface becomes rough due to (111) facets formation in the high temperature region and the rate-limiting step is presumably a diffusion process of Si to be trapped at the kink sites associated with these facets. Defect formation is found to be initiated by 5-membered rings created at the a/c interface. These mismatched configurations at the interface give rise to (111) stacking faults during further SPE growth.


2019 ◽  
Vol 16 (3) ◽  
pp. 291-300
Author(s):  
Saumya K. Patel ◽  
Mohd Athar ◽  
Prakash C. Jha ◽  
Vijay M. Khedkar ◽  
Yogesh Jasrai ◽  
...  

Background: Combined in-silico and in-vitro approaches were adopted to investigate the antiplasmodial activity of Catharanthus roseus and Tylophora indica plant extracts as well as their isolated components (vinblastine, vincristine and tylophorine). </P><P> Methods: We employed molecular docking to prioritize phytochemicals from a library of 26 compounds against Plasmodium falciparum multidrug-resistance protein 1 (PfMDR1). Furthermore, Molecular Dynamics (MD) simulations were performed for a duration of 10 ns to estimate the dynamical structural integrity of ligand-receptor complexes. </P><P> Results: The retrieved bioactive compounds viz. tylophorine, vinblastin and vincristine were found to exhibit significant interacting behaviour; as validated by in-vitro studies on chloroquine sensitive (3D7) as well as chloroquine resistant (RKL9) strain. Moreover, they also displayed stable trajectory (RMSD, RMSF) and molecular properties with consistent interaction profile in molecular dynamics simulations. </P><P> Conclusion: We anticipate that the retrieved phytochemicals can serve as the potential hits and presented findings would be helpful for the designing of malarial therapeutics.


Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1711
Author(s):  
Mohamed Ahmed Khaireh ◽  
Marie Angot ◽  
Clara Cilindre ◽  
Gérard Liger-Belair ◽  
David A. Bonhommeau

The diffusion of carbon dioxide (CO2) and ethanol (EtOH) is a fundamental transport process behind the formation and growth of CO2 bubbles in sparkling beverages and the release of organoleptic compounds at the liquid free surface. In the present study, CO2 and EtOH diffusion coefficients are computed from molecular dynamics (MD) simulations and compared with experimental values derived from the Stokes-Einstein (SE) relation on the basis of viscometry experiments and hydrodynamic radii deduced from former nuclear magnetic resonance (NMR) measurements. These diffusion coefficients steadily increase with temperature and decrease as the concentration of ethanol rises. The agreement between theory and experiment is suitable for CO2. Theoretical EtOH diffusion coefficients tend to overestimate slightly experimental values, although the agreement can be improved by changing the hydrodynamic radius used to evaluate experimental diffusion coefficients. This apparent disagreement should not rely on limitations of the MD simulations nor on the approximations made to evaluate theoretical diffusion coefficients. Improvement of the molecular models, as well as additional NMR measurements on sparkling beverages at several temperatures and ethanol concentrations, would help solve this issue.


CrystEngComm ◽  
2021 ◽  
Author(s):  
Andrey Sarikov ◽  
Anna Marzegalli ◽  
Luca Barbisan ◽  
Massimo Zimbone ◽  
Corrado Bongiorno ◽  
...  

In this work, annihilation mechanism of stacking faults (SFs) in epitaxial 3C-SiC layers grown on Si(001) substrates is studied by molecular dynamics (MD) simulations. The evolution of SFs located in...


Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 347
Author(s):  
Wenlin Zhang ◽  
Lingyi Zou

We apply molecular dynamics (MD) simulations to investigate crystal nucleation in incompatible polymer blends under deep supercooling conditions. Simulations of isothermal nucleation are performed for phase-separated blends with different degrees of incompatibility. In weakly segregated blends, slow and incompatible chains in crystallizable polymer domains can significantly hinder the crystal nucleation and growth. When a crystallizable polymer is blended with a more mobile species in interfacial regions, enhanced molecular mobility leads to the fast growth of crystalline order. However, the incubation time remains the same as that in pure samples. By inducing anisotropic alignment near the interfaces of strongly segregated blends, phase separation also promotes crystalline order to grow near interfaces between different polymer domains.


2016 ◽  
Vol 18 (37) ◽  
pp. 25806-25816 ◽  
Author(s):  
Carlos Navarro-Retamal ◽  
Anne Bremer ◽  
Jans Alzate-Morales ◽  
Julio Caballero ◽  
Dirk K. Hincha ◽  
...  

Unfolding of intrinsically unstructured full-length LEA proteins in a differentially crowded environment can be modeled by 30 ns MD simulations in accordance with experimental data.


1995 ◽  
Vol 396 ◽  
Author(s):  
M. tang ◽  
L. colombo ◽  
T. Diaz De La Rubia

AbstractTight-binding molecular dynamics (TBMD) simulations are performed (i) to evaluate the formation and binding energies of point defects and defect clusters, (ii) to compute the diffusivity of self-interstitial and vacancy in crystalline silicon, and (iii) to characterize the diffusion path and mechanism at the atomistic level. In addition, the interaction between individual defects and their clustering is investigated.


Symmetry ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1259
Author(s):  
Maksymilian Dziura ◽  
Basel Mansour ◽  
Mitchell DiPasquale ◽  
P. Charukeshi Chandrasekera ◽  
James W. Gauld ◽  
...  

In this review, we delve into the topic of the pulmonary surfactant (PS) system, which is present in the respiratory system. The total composition of the PS has been presented and explored, from the types of cells involved in its synthesis and secretion, down to the specific building blocks used, such as the various lipid and protein components. The lipid and protein composition varies across species and between individuals, but ultimately produces a PS monolayer with the same role. As such, the composition has been investigated for the ways in which it imposes function and confers peculiar biophysical characteristics to the system as a whole. Moreover, a couple of theories/models that are associated with the functions of PS have been addressed. Finally, molecular dynamic (MD) simulations of pulmonary surfactant have been emphasized to not only showcase various group’s findings, but also to demonstrate the validity and importance that MD simulations can have in future research exploring the PS monolayer system.


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