Atomic-scale models of early-stage alkali depletion and SiO2-rich gel formation in bioactive glasses

2015 ◽  
Vol 17 (4) ◽  
pp. 2696-2702 ◽  
Author(s):  
Antonio Tilocca
Keyword(s):  
Molecular Dynamics ◽  
Early Stage ◽  
Atomic Scale ◽  
Gel Formation ◽  
Gel Structure ◽  
Bioactive Glasses ◽  
Direct Mechanism ◽  
Scale Models ◽  
Dynamics Simulations ◽  
45S5 Bioglass

Molecular dynamics simulations of Na+/H+-exchanged 45S5 Bioglass® reveal the co-existence of bonded and non-bonded hydroxyls, suggesting a direct mechanism for forming a silica-rich gel structure upon the initial ion exchange.

Atomic-Scale Probing of Defect-Assisted Ga Intercalation Through Graphene Using ReaxFF Molecular Dynamics Simulations

2021 ◽  
Author(s):  
Nadire Nayir ◽  
Mert Y. Sengul ◽  
Anna L. Costine ◽  
Petra Reinke ◽  
Siavash Rajabpour ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Atomic Scale ◽  
Dynamics Simulations

Structure and dynamics of gold nanoparticles decorated with chitosan–gentamicin conjugates: ReaxFF molecular dynamics simulations to disclose drug delivery

2019 ◽  
Vol 21 (24) ◽  
pp. 13099-13108 ◽  
Author(s):  
Susanna Monti ◽  
Jiya Jose ◽  
Athira Sahajan ◽  
Nandakumar Kalarikkal ◽  
Sabu Thomas
Keyword(s):  
Drug Delivery ◽  
Molecular Dynamics ◽  
Gold Nanoparticles ◽  
Molecular Dynamics Simulations ◽  
Atomic Scale ◽  
Functionalized Gold Nanoparticles ◽  
Structure And Dynamics ◽  
Antibiotic Drug ◽  
Dynamics Simulations

Functionalized gold nanoparticles for antibiotic drug delivery: from the nanoscale to the atomic scale.

scholarly journals Role of Internal Stress in the Early-Stage Nucleation of Amorphous Calcium Carbonate Gels

2020 ◽  
Vol 10 (12) ◽  
pp. 4359 ◽  
Author(s):  
Qi Zhou ◽  
Tao Du ◽  
Lijie Guo ◽  
Gaurav Sant ◽  
Mathieu Bauchy
Keyword(s):  
Molecular Dynamics ◽  
Calcium Carbonate ◽  
Driving Force ◽  
Early Stage ◽  
Local Stress ◽  
Amorphous Calcium Carbonate ◽  
Local Coordination ◽  
Dynamics Simulations ◽  
Over Time

Although calcium carbonate (CaCO3) precipitation plays an important role in nature, its mechanism remains only partially understood. Further understanding the atomic driving force behind the CaCO3 precipitation could be key to facilitate the capture, immobilization, and utilization of CO2 by mineralization. Here, based on molecular dynamics simulations, we investigate the mechanism of the early-stage nucleation of an amorphous calcium carbonate gel. We show that the gelation reaction manifests itself by the formation of some calcium carbonate clusters that grow over time. Interestingly, we demonstrate that the gelation reaction is driven by the existence of some competing local molecular stresses within the Ca and C precursors, which progressively get released upon gelation. This internal molecular stress is found to originate from the significantly different local coordination environments exhibited by Ca and C atoms. These results highlight the key role played by the local stress acting within the atomic network in governing gelation reactions.

Impact of Molecular Dynamics Simulations on Research and Development of Semiconductor Materials

MRS Advances ◽  
2019 ◽  
Vol 4 (61-62) ◽  
pp. 3381-3398
Author(s):  
Xiaowang Zhou
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Recent Progress ◽  
Defect Formation ◽  
Atomic Scale ◽  
Semiconductor Materials ◽  
Formation Mechanisms ◽  
Graphene Growth ◽  
First Case ◽  
Dynamics Simulations

ABSTRACTAtomic scale defects critically limit performance of semiconductor materials. To improve materials, defect effects and defect formation mechanisms must be understood. In this paper, we demonstrate multiple examples where molecular dynamics simulations have effectively addressed these issues that were not well addressed in prior experiments. In the first case, we report our recent progress on modelling graphene growth, where we found that defects in graphene are created around periphery of islands throughout graphene growth, not just in regions where graphene islands impinge as believed previously. In the second case, we report our recent progress on modelling TlBr, where we discovered that under an electric field, edge dislocations in TlBr migrate in both slip and climb directions. The climb motion ejects extensive vacancies that can cause the rapid aging of the material seen in experiments. In the third case, we discovered that the growth of InGaN films on (0001) surfaces suffers from a serious polymorphism problem that creates enormous amounts of defects. Growth on ($11\bar{2}0$) surfaces, on the other hand, results in single crystalline wurtzite films without any of these defects. In the fourth case, we first used simulations to derive dislocation energies that do not possess any noticeable statistical errors, and then used these error-free methods to discover possible misuse of misfit dislocation theory in past thin film studies. Finally, we highlight the significance of molecular dynamics simulations in reducing defects in the design space of nanostructures.

Experimental Studies and Molecular Dynamics Simulations of the Sliding Contact of Metallic Glass

2000 ◽  
Vol 644 ◽  
Author(s):  
Xi-Yong Fu ◽  
Michael L. Falk ◽  
David A. Rigney
Keyword(s):  
Molecular Dynamics ◽  
Metallic Glass ◽  
Molecular Dynamics Simulations ◽  
Bulk Metallic Glass ◽  
Amorphous Material ◽  
Experimental Studies ◽  
Sliding Contact ◽  
Atomic Scale ◽  
Sliding Interface ◽  
Dynamics Simulations

AbstractTribological properties of bulk metallic glass Zr41.2Ti13.8Cu12.5Ni10.0Be22.5 were studied experimentally using a pin/disk geometry without lubrication. Experimental observations were compared with 2D molecular dynamics simulations of amorphous material in sliding contact. The friction coefficient and the wear rate of bulk metallic glass (BMG) depend on normal load and test environment. The sliding of annealed BMG re-amorphizes devitrified material. A mechanically mixed layer is generated during sliding; this layer has enhanced oxygen content if the sliding is in air. The MD simulations show that atomic scale mixing occurs across the sliding interface. The growth kinetics of the mixing process scales with the square root of time. In the simulations, a low density region is generated near the sliding interface; it corresponds spatially to the softer layer detected in experiments. Subsurface displacement profiles produced by sliding and by simulation are very similar and are consistent with the flow patterns expected from a simple Navier-Stokes analysis when the stress state involves both compression and shear.

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