scholarly journals Characterization of Atomic Surface Roughness in Nanometric Machining Molecular Dynamics (MD) Simulations

2016 ◽  
Vol 13 (1) ◽  
pp. 31-39 ◽  
Author(s):  
Akinjide Olufemi Oluwajobi ◽  
Xun Chen
2016 ◽  
Vol 686 ◽  
pp. 194-199
Author(s):  
Akinjide O. Oluwajobi ◽  
Xun Chen

There is a need to choose appropriate interatomic empirical potentials for the molecular dynamics (MD) simulation of nanomachining, so as to represent chip formation and other cutting processes reliably. Popularly applied potentials namely; Lennard-Jones (LJ), Morse, Embedded Atom Method (EAM) and Tersoff were employed in the molecular dynamics simulation of nanometric machining of copper workpiece with diamond tool. The EAM potentials were used for the modelling of the copper-copper atom interactions. The pairs of EAM-Morse and EAM-LJ were used for the workpiece-tool (copper-diamond) atomic interface. The Tersoff potential was used for the carbon-carbon interactions in the diamond tool. Multi-pass simulations were carried out and it was observed that the EAM-LJ and the EAM-Morse pair potentials with the tool modelled as deformable with Tersoff potential were best suitable for the simulation. The former exhibit the lowest cutting forces and the latter has the lowest potential energy.


RSC Advances ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 1341-1353 ◽  
Author(s):  
Qihong Fang ◽  
Yuanyuan Tian ◽  
Jia Li ◽  
Qiong Wang ◽  
Hong Wu

The nanometric machining of Cu/Ag bilayers and pure Cu film is performed using molecular dynamics (MD) simulations.


Author(s):  
Bo Qiu ◽  
Lin Sun ◽  
Xiulin Ruan

In this paper, by employing the previously developed two-body interatomic potentials for bismuth telluride, molecular dynamics (MD) simulations are used to describe the thermoelectric properties, namely the lattice thermal conductivity, of Bi2Te3 nanowires. Cylindrical nanowires with both smooth surface and sawtooth surface roughness are studied, aiming at revealing the effects of phonon confinement in 1-D structures, phonon boundary scatterings and surface roughness on the lattice thermal conductivity of Bi2Te3 nanowires. In the end, the influence of various phonon scattering mechanisms on the nanostructures under study are summarized, possible paths to reduce lattice thermal conductivity in nanostructured Bi2Te3, which is favorable for enhancing thermoelectric performance, are pointed out.


2020 ◽  
Vol 36 (11) ◽  
pp. 3576-3577 ◽  
Author(s):  
Marcelo D Polêto ◽  
Bruno I Grisci ◽  
Marcio Dorn ◽  
Hugo Verli

Abstract Motivation The conformational space of small molecules can be vast and difficult to assess. Molecular dynamics (MD) simulations of free ligands in solution have been applied to predict conformational populations, but their characterization is often based on clustering algorithms or manual efforts. Results Here, we introduce ConfID, an analytical tool for conformational characterization of small molecules using MD trajectories. The evolution of conformational sampling and population frequencies throughout trajectories is calculated to check for sampling convergence while allowing to map relevant conformational transitions. The tool is designed to track conformational transition events and calculate time-dependent properties for each conformational population detected. Availability and implementation Toolkit and documentation are freely available at http://sbcb.inf.ufrgs.br/confid Contact [email protected] or [email protected] Supplementary information Supplementary data are available at Bioinformatics online.


Author(s):  
R. Promyoo ◽  
H. El-Mounayri ◽  
X. Yang

Molecular Dynamics (MD) simulations of nanometric machining of single-crystal copper were conducted at a conventional cutting speed (5m/s) and different depths of cut (0.724 – 2.172 nm). The simulations were carried out to predict cutting forces and investigate the mechanism of chip formation at the nano level. The effect of tool rake angles and depths of cut on the mechanism of chip formation were also investigated. Tools with different rake angles, namely 0°, 5°, 10°, 15°, 30°, and 45°, were used. It was found that the cutting force, thrust force, and the ratio of the thrust force to cutting force decrease with increasing rake angle. However, the ratio of the thrust force to the cutting force is found to be independent of the depth of cut.


2000 ◽  
Vol 653 ◽  
Author(s):  
Celeste Sagui ◽  
Thoma Darden

AbstractFixed and induced point dipoles have been implemented in the Ewald and Particle-Mesh Ewald (PME) formalisms. During molecular dynamics (MD) the induced dipoles can be propagated along with the atomic positions either by interation to self-consistency at each time step, or by a Car-Parrinello (CP) technique using an extended Lagrangian formalism. The use of PME for electrostatics of fixed charges and induced dipoles together with a CP treatment of dipole propagation in MD simulations leads to a cost overhead of only 33% above that of MD simulations using standard PME with fixed charges, allowing the study of polarizability in largemacromolecular systems.


Author(s):  
Tian Lu ◽  
Qinxue Chen ◽  
Zeyu Liu

Although cyclo[18]carbon has been theoretically and experimentally investigated since long time ago, only very recently it was prepared and directly observed by means of STM/AFM in condensed phase (Kaiser et al., <i>Science</i>, <b>365</b>, 1299 (2019)). The unique ring structure and dual 18-center π delocalization feature bring a variety of unusual characteristics and properties to the cyclo[18]carbon, which are quite worth to be explored. In this work, we present an extremely comprehensive and detailed investigation on almost all aspects of the cyclo[18]carbon, including (1) Geometric characteristics (2) Bonding nature (3) Electron delocalization and aromaticity (4) Intermolecular interaction (5) Reactivity (6) Electronic excitation and UV/Vis spectrum (7) Molecular vibration and IR/Raman spectrum (8) Molecular dynamics (9) Response to external field (10) Electron ionization, affinity and accompanied process (11) Various molecular properties. We believe that our full characterization of the cyclo[18]carbon will greatly deepen researchers' understanding of this system, and thereby help them to utilize it in practice and design its various valuable derivatives.


Author(s):  
Tian Lu ◽  
Qinxue Chen ◽  
Zeyu Liu

Although cyclo[18]carbon has been theoretically and experimentally investigated since long time ago, only very recently it was prepared and directly observed by means of STM/AFM in condensed phase (Kaiser et al., <i>Science</i>, <b>365</b>, 1299 (2019)). The unique ring structure and dual 18-center π delocalization feature bring a variety of unusual characteristics and properties to the cyclo[18]carbon, which are quite worth to be explored. In this work, we present an extremely comprehensive and detailed investigation on almost all aspects of the cyclo[18]carbon, including (1) Geometric characteristics (2) Bonding nature (3) Electron delocalization and aromaticity (4) Intermolecular interaction (5) Reactivity (6) Electronic excitation and UV/Vis spectrum (7) Molecular vibration and IR/Raman spectrum (8) Molecular dynamics (9) Response to external field (10) Electron ionization, affinity and accompanied process (11) Various molecular properties. We believe that our full characterization of the cyclo[18]carbon will greatly deepen researchers' understanding of this system, and thereby help them to utilize it in practice and design its various valuable derivatives.


2020 ◽  
Author(s):  
Matías R. Machado ◽  
Sergio Pantano

<p> Despite the relevance of properly setting ionic concentrations in Molecular Dynamics (MD) simulations, methods or practical rules to set ionic strength are scarce and rarely documented. Based on a recently proposed thermodynamics method we provide an accurate rule of thumb to define the electrolytic content in simulation boxes. Extending the use of good practices in setting up MD systems is promptly needed to ensure reproducibility and consistency in molecular simulations.</p>


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.


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