scholarly journals Ideal Oscillation of a Hydrogenated Deformable Rotor in a Gigahertz Rotation–Translation Nanoconverter at Low Temperatures

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 1969
Author(s):  
Bo Song ◽  
Jiao Shi ◽  
Jinbao Wang ◽  
Jianhu Shen ◽  
Kun Cai
Keyword(s):  
Molecular Dynamics ◽  
Low Temperatures ◽  
Rotational Frequency ◽  
The Other ◽  
Present System ◽  
Eccentric Rotation ◽  
Axial Oscillation ◽  
Axial Translation ◽  
Dynamics Simulations ◽  
Thermal Vibrations

It was discovered that large-amplitude axial oscillation can occur on a rotor with an internally hydrogenated deformable part (HDP) in a rotation–translation nanoconverter. The dynamic outputs of the system were investigated using molecular dynamics simulations. When an input rotational frequency (100 GHz > ω > 20 GHz) was applied at one end of the rotor, the HDP deformed under the centrifugal and van der Waals forces, which simultaneously led to the axial translation of the other end of the rotor. Except at too high an input rotational frequency (e.g., >100 GHz), which led to eccentric rotation and even collapse of the system, the present system could generate a periodic axial oscillation with an amplitude above 0.5 nm at a temperature below 50 K. In other ranges of temperature and amplitude, the oscillation dampened quickly due to the drastic thermal vibrations of the atoms. Furthermore, the effects of the hydrogenation scheme and the length of HDP on the equilibrium position, amplitude, and frequency of oscillation were investigated. The conclusions can be applied to the design of an ideal nano-oscillator based on the present rotation–translation converter model.

Rotation-induced axial oscillation of a composite nanoconvertor at low temperature

2020 ◽  
pp. 107754632093711
Author(s):  
Bo Song ◽  
Kun Cai ◽  
Jiao Shi ◽  
Qing-Hua Qin
Keyword(s):  
Molecular Dynamics ◽  
Low Temperature ◽  
Large Amplitude ◽  
Oscillation Amplitude ◽  
Axial Direction ◽  
Axial Vibration ◽  
Axial Oscillation ◽  
Axial Translation ◽  
Vibration Responses ◽  
Dynamics Simulations

We propose a model of a nanostructure which can transform an input rotation into an output oscillation. In the model, the rotor has two identical internally hydrogenated deformable parts. The mechanism is that the rotation-induced centrifugal force and van der Waals force drive the recoverable deformation of the hydrogenated deformable parts, which gives rise to the axial translation of the free end of the rotor. Once the two hydrogenated deformable parts deform periodically, the free end of the rotor oscillates periodically in the axial direction. Molecular dynamics simulations are conducted to reveal the dynamic response of the system at low temperature. Four main types of deformation and the first three orders of vibration responses of the hydrogenated deformable parts are analyzed. Synchronous breathing vibration of the two hydrogenated deformable parts produces ideal oscillation with large amplitude. Asynchronous axial vibration of the hydrogenated deformable parts reduces the oscillation amplitude or produces beat vibration. The way to control the amplitude of the axial oscillation/vibration is given.

scholarly journals Systems with Size and Energy Polydispersity: From Glasses to Mosaic Crystals

Entropy ◽  
2020 ◽  
Vol 22 (5) ◽  
pp. 570
Author(s):  
Itay Azizi ◽  
Yitzhak Rabin
Keyword(s):  
Low Temperatures ◽  
The Other ◽  
Interaction Parameters ◽  
2D Systems ◽  
Small Particles ◽  
Strength Of Interaction ◽  
High Interaction ◽  
Mosaic Crystals ◽  
Dynamics Simulations ◽  
Entropic Effects

We use Langevin dynamics simulations to study dense 2d systems of particles with both size and energy polydispersity. We compare two types of bidisperse systems which differ in the correlation between particle size and interaction parameters: in one system big particles have high interaction parameters and small particles have low interaction parameters, while in the other system the situation is reversed. We study the different phases of the two systems and compare them to those of a system with size but not energy bidispersity. We show that, depending on the strength of interaction between big and small particles, cooling to low temperatures yields either homogeneous glasses or mosaic crystals. We find that systems with low mixing interaction, undergo partial freezing of one of the components at intermediate temperatures, and that while this phenomenon is energy-driven in both size and energy bidisperse systems, it is controlled by entropic effects in systems with size bidispersity only.

scholarly journals Local Structuring of Diketopyrrolopyrrole (DPP)-Based Semiconducting Polymers Using Molecular Dynamics Simulations

2020 ◽  
Author(s):  
Maryam Reisjalali ◽  
Jose Javier Burgos Marmol ◽  
Alessandro Troisi
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Electronic Devices ◽  
Atomic Level ◽  
Semiconducting Polymers ◽  
The Other ◽  
Charge Mobility ◽  
High Charge ◽  
High Performing ◽  
Dynamics Simulations

High performing organic semiconducting polymers show great potentials for use in electronic devices which is greatly dependent on the material crystallinity and packing. A series of short oligomers of the diketopyrrolopyrrole (DPP)-based materials that have shown to have high charge mobility are studied to understand the local structuring at atomic level for these materials. The simulations show that the tendency for this material class to form aggregates is driven by the interaction between DPP fragments, but this is modulated by the other conjugated fragments of the materials which afect the rigidity of the polymer and the ability to form aggregates of larger size.<br>

MOLECULAR DYNAMICS STUDY OF THE COALESCENCE OF EQUAL AND UNEQUAL SIZED Cu NANOPARTICLES

2009 ◽  
Vol 20 (02) ◽  
pp. 179-196 ◽  
Author(s):  
H. H. KART ◽  
G. WANG ◽  
I. KARAMAN ◽  
T. ÇAĞIN
Keyword(s):  
Molecular Dynamics ◽  
Theoretical Calculations ◽  
The Other ◽  
Model Systems ◽  
Heat Of Fusion ◽  
Sintering Process ◽  
Melting Temperatures ◽  
Different Temperatures ◽  
Dynamics Simulations ◽  
Good Agreement

Molecular dynamics simulations technique is used to study the consolidation of two nanoparticles of Cu element. We have studied sintering processes of two nanoparticles at different temperatures. Two model systems with 4 and 10 nm diameter of particles are selected to study the sintering process of the two nanoparticles. Orientation effects on the physical properties of consolidation of two nanoparticles with respect to each other are investigated. Temperature effects on the consolidation of two nanoparticles are also studied. The order of the values obtained in the simulation for the constant volume heat capacity and latent heat of fusion is good agreement with the bulk results. Moreover, we have investigated the size effects on the consolidation of two different sizes of nanoparticles, that is, one particle of diameter with 10 nm is fixed while the other one is changing from 1 to 10 nm. Melting temperatures of the copper nanoparticles are found to be decreased as the size of the particle decreases. It is found that simulation results are compatible with the other theoretical calculations.

Spectroscopic Ellipsometry and Band Structure of Si1–yCy Alloys Grown Pseudomorphically on Si (001)

1995 ◽  
Vol 379 ◽  
Author(s):  
Stefan Zollner ◽  
Craig M. Herzinger ◽  
John A. Woollam ◽  
Subramanian S. Lyer ◽  
Adrian P. Powell ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Shear Stress ◽  
Low Temperatures ◽  
Molecular Beam ◽  
Tight Binding ◽  
Analytical Line ◽  
Virtual Crystal Approximation ◽  
Line Shapes ◽  
Dynamics Simulations ◽  
Derivatives Of

ABSTRACTWe have measured the dielectric functions of three Si1−yCy, alloys layers (y ≤1.4%) grown pseudomorphically on Si (001) substrates using molecular beam epitaxy at low temperatures. From the numerical derivatives of the measured spectra, we determine the critical point energies E′0 and E1 as a function of y (y ≤ 1.4%) using a comparison with analytical line shapes and analyze these energies in terms of the expected shifts and splittings due to negative hydrostatic pressure, shear stress, and alloying. Our data agree well with the calculated shifts for El, but the E′0 energies are lower than expected. We discuss our results in comparison with recent tight-binding molecular dynamics simulations by Demkov and Sankey (Phys. Rev. B 48, 2207, 1993) prediciting a total breakdown of the virtual-crystal approximation for such alloys.

scholarly journals Catalytic Effect of Ti or Pt in a Hexagonal Boron Nitride Surface for Capturing CO2

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 662
Author(s):  
J. M. Ramirez-de-Arellano ◽  
A. Fransuani Jiménez G. ◽  
L. F. Magaña
Keyword(s):  
Molecular Dynamics ◽  
Boron Nitride ◽  
Molecular Dynamics Simulations ◽  
First Principles ◽  
Atmospheric Pressure ◽  
Catalytic Effect ◽  
Hexagonal Boron Nitride ◽  
The Other ◽  
Adsorption Of Co2 ◽  
Dynamics Simulations

We investigated the effect of doping a hexagonal boron nitride surface (hBN) with Ti or Pt on the adsorption of CO2. We performed first-principles molecular dynamics simulations (FPMD) at atmospheric pressure, and 300 K. Pristine hBN shows no interaction with the CO2 molecule. We allowed the Ti and Pt atoms to interact separately, with either a B-vacancy or an N-vacancy. Both Ti and Pt ended chemisorbed on the surface. The system hBN + Ti always chemisorbed the CO2 molecule. This chemisorption happens in two possible ways. One is without dissociation, and in the other, the molecule breaks in CO and O. However, in the case of the Pt atom as dopant, the resulting system repels the CO2 molecule.

Surface Ligand Rigidity Modulates Lipid Raft Affinity of Ultra-small Hydrophobic Nanoparticles: Insights from Molecular Dynamics Simulations

Nanoscale ◽  
2021 ◽  
Author(s):  
Xiaoqian Lin ◽  
Xubo Lin
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Lipid Rafts ◽  
Lipid Raft ◽  
The Other ◽  
Membrane Domains ◽  
Surface Ligand ◽  
Proper Functions ◽  
Dynamics Simulations ◽  
Small Hydrophobic

Differential preferences between lipids and proteins drive the formation of dynamical nanoscale membrane domains (lipid rafts), which play key roles in proper functions of the cell. On the other hand,...

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