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Dielectrophoresis of nanocolloids: A molecular dynamics study 总被引:1,自引:0,他引:1
Salonen E Terama E Vattulainen I Karttunen M 《The European physical journal. E, Soft matter》2005,18(2):133-142
Dielectrophoresis (DEP), the motion of polarizable particles in non-uniform electric fields, has become an important tool
for the transport, separation, and characterization of microparticles in biomedical and nanoelectronics research. In this
article we present, to our knowledge, the first molecular dynamics simulations of DEP of nanometer-sized colloidal particles.
We introduce a simplified model for a polarizable nanoparticle, consisting of a large charged macroion and oppositely charged
microions, in an explicit solvent. The model is then used to study DEP motion of the particle at different combinations of
temperature and electric field strength. In accord with linear response theory, the particle drift velocities are shown to
be proportional to the DEP force. Analysis of the colloid DEP mobility shows a clear time dependence, demonstrating the variation
of friction under non-equilibrium. The time dependence of the mobility further results in an apparent weak variation of the
DEP displacements with temperature. 相似文献
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《Current Applied Physics》2014,14(9):1216-1227
With the rapid progression of bionanorobotics, manipulation of nano-scale biosamples is becoming increasingly attractive for different biological purposes. Nevertheless, the interaction between a robotic probe and a biological sample is poorly understood and the conditions for appropriate handling is not well-known. Here, we use the molecular dynamics (MD) simulation method to investigate the manipulation process when a nanoprobe tries to move a biosample on a substrate. For this purpose, we have used Ubiquitin (UBQ) as the biomolecule, a single-walled carbon nanotube (SWCNT) as the manipulation probe, and a double-layered graphene sheets as the substrate. A series of simulations were conducted to study the effects of different conditions on the success of the manipulation process. These conditions include the tip diameter, the vertical gap between the tip and substrate, and the initial orientation of the protein. Also we have studied two strategies for the manipulation of the protein by a nano-scale probe that we have named pushing and pulling. Interaction force between carbon nanotube (CNT) tips and the biomolecule, the root-mean-square deviation (RMSD), and the radius of gyration of the protein are monitored for different conditions. We found that larger tip diameters, smaller gaps between tip and substrate, and a pulling strategy increase the chance of a successful manipulation. 相似文献
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We simulate the twist of carbon nanotubes using atomic molecular dynamic simulations. The ultimate twist angle per unit length and the deformation energy are calculated for nanotubes of different geometries. It is found that the thick tube is harder to be twisted while the thin tube exhibits higher ultimate twisting ratio. For multi-walled nanotubes, the zigzag tube is found to be able to stand more deformation than the armchair one. We observed the surface transformation during twisting. Formation of structural defects is observed prior to fracture. 相似文献
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Gülen Ferah Kemal Colakoglu Yasemin Oztekin Ciftci Soner Ozgen Sefa Kazanc 《Central European Journal of Physics》2007,5(2):207-220
In this study, molecular dynamics simulations are performed by using a modified form of Morse potential function in the framework
of the Embedded Atom Method (EAM). Temperature-and pressure-dependent behaviours of bulk modulus, second-order elastic constants
(SOEC), and the linear-thermal expansion coefficient is calculated and compared with the available experimental data. The
melting temperature is estimated from 3 different plots. The obtained results are in agreement with the available experimental
findings for iridium.
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The melting kinetics of bulk SiC is studied by using classical molecular dynamics simulation.The mean square displacement,diffusion coefficient,Lindemann index and non-Gaussian parameter are used to analyze the melt nucleation and macrokinetics in the melting process.Melting occurs when the superheated crystal spontaneously generates many Lindemann particles in which they coalesce together to form melt nucleation inside the crystal.The melting process is similar to the solidification process,but also experiences three processes such as nucleation,growth and relaxation.The melting process can be divided into premelting,accelerated melting and relaxation stages.Using the sectional method can properly reflect the kinetic characteristics of the melting process. 相似文献
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Hirshfeld D Rapaport DC 《Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics》2000,61(1):R21-R24
Molecular dynamics methods have been used in a quantitative study of the growth and decay of Taylor vortices in a fluid confined between concentric cylinders when the rotation of the inner cylinder is instantaneously started or stopped. Analysis of the temporal evolution of the vortex flow fields shows that the behavior of this microscopic system agrees with experiment. In order to make the analysis entirely self-contained, torque measurements have been used to determine the effective viscosity of the fluid. 相似文献
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Molecular dynamics calculations were carried out in order to investigate the hydration structure of uranyl in aqueous solution. The CF1 model of flexible water molecules is used. This model allows one to investigate a hydrolysis reaction for water molecules in the first uranyl hydration shell. Charge redistribution effects on hydrolysis products are also taken into account. We found five ligands in uranyl hydration shell, which is of bipyramidal pentacoordinated structure. The charge redistribution effects resulted in ligands of four water molecules and one hydroxyl, which was found closer to uranium than the other ligands. 相似文献
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The high temperature (T > 0.5Tm) structure of the previously studied fcc (310)[001] Σ = 5 grain boundary is reinvestigated in order to determine the nature of the diffusion mechanism. The obtained results confirm our earlier conclusion that the grain boundary remains crystalline, but highly disordered, up to the melting point. In addition, we explored the diffusion mechanisms in the fcc (210)[001] Σ = 5 grain boundary. As expected, diffusion occurs mainly by the vacancy migration. The jump frequencies determined by the molecular dynamics simulation have been used to evaluate the tracer correlation factor and the anisotropy of the intergranular diffusion coefficient through a random walk model simulation of the vacancy migration. 相似文献
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We have performed molecular dynamics simulations for PtN + PtN → Pt2N (N = 147, 324, 500,792), to investigate the effect of size and substrate on coalescence temperature. Our simulations show that platinum nanoclusters coalesce at the temperatures lower than the cluster melting point. The difference between coalescence and melting temperatures decreases with the increase in cluster size and presence of substrate. These thermal behaviors affect catalytical properties of nanoclusters and the substrate, as an environment, has major effect on activity of metal nanoclusters. 相似文献
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In this work,three-dimensional molecular dynamics simulation is carried out to elucidate the nanoindentation behaviour of single crystal Ni.The substrate indenter system is modelled using hybrid interatomic potentials including the manybody potential(embedded atom method) and two-body Morse potential.The spherical indenter is chosen,and the simulation is performed for different loading rates from 10 m/s to 200 m/s.Results show that the maximum indentation load and hardness of the system increase with the increase of velocity.The effect of indenter size on the nanoindentation response is also analysed.It is found that the maximum indentation load is higher for the large indenter whereas the hardness is higher for the smaller indenter.Dynamic nanoindentation is carried out to investigate the behaviour of Ni substrate to multiple loading-unloading cycles.It is observed from the results that the increase in the number of loading unloading cycles reduces the maximum load and hardness of the Ni substrate.This is attributed to the decrease in recovery force due to defects and dislocations produced after each indentation cycle. 相似文献