The Diffusion Isotope Effect and Diffusion Mechanism in Liquid Cu-Ag and Cu-Ni Alloys

2021 ◽  
Vol 413 ◽  
pp. 136-145
Author(s):  
Ujjal Sarder ◽  
Tumpa R. Paul ◽  
Irina V. Belova ◽  
Graeme E. Murch

In this paper, the diffusion isotope effect and diffusion mechanism are investigated by means of molecular dynamics simulations in two liquid alloys, Ni-Ag and Ni-Cu. The values for the diffusion isotope effect parameter allow for the estimate of the number of atoms which are moving cooperatively in a basic diffusion event as experienced by a given atomic species. It is shown that the composition dependence of ND is typically very small. However, the temperature dependence of this parameter is much more pronounced. In addition, it is shown that, on average, in these alloys and temperatures considered, ND is limited to the range: 5<ND<17. This is consistent with results of molecular dynamics simulations on the average coordination number calculations. This would suggest that, together with a given atom, depending on temperature, the neighbouring atoms are all involved in the basic diffusion event.

2020 ◽  
Vol 5 (1) ◽  
pp. 304-316 ◽  
Author(s):  
Jonathan K. Sheavly ◽  
Jake I. Gold ◽  
Manos Mavrikakis ◽  
Reid C. Van Lehn

Molecular dynamics simulations predict the effect of analyte transport on the activation time of chemoresponsive liquid crystal sensors to improve sensor selectivity.


2008 ◽  
Vol 112 (42) ◽  
pp. 13273-13284 ◽  
Author(s):  
Shengting Cui ◽  
Junwu Liu ◽  
Myvizhi Esai Selvan ◽  
Stephen J. Paddison ◽  
David J. Keffer ◽  
...  

2007 ◽  
Vol 121-123 ◽  
pp. 1109-1114
Author(s):  
M.L. Liao ◽  
Shin Pon Ju ◽  
Jenn Sen Lin ◽  
Y.S. Lin

Rheological properties of water films nanoconfined in two parallel Au plates are investigated with the aid of molecular dynamics simulations. The density distribution, velocity profile, and diffusion coefficients of the water film in a Couette flow are studied. Shear viscosity and its dependence on the shear rate of the water film are also examined in the present research. It is found that the density of the water molecules near the plates is much higher than that in the other regions. This indicates that many water molecules are adsorbed by the plates and adsorbed layers are formed in the vicinity of the plates. The diffusion of the whole film increases dramatically as the shear rate becomes greater than 1010 s-1. The shear viscosity decreases as the shear rate increases, especially for the water film with a small thickness, which indicates the shear-thinning behavior for viscosity of the nanoconfined film. Moreover, an increase in shear viscosity with a decrease in the film thickness can also be found in the present study.


Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 344 ◽  
Author(s):  
Qin Qin ◽  
Tingwei Sun ◽  
Hanxiao Wang ◽  
Pascal Brault ◽  
Haojie An ◽  
...  

Carbon honeycomb has a nanoporous structure with good mechanical properties including strength. Here we investigate the adsorption and diffusion of hydrogen in carbon honeycomb via grand canonical Monte Carlo simulations and molecular dynamics simulations including strength. Based on the adsorption simulations, molecular dynamics simulations are employed to study the effect of pressure and temperature for the adsorption and diffusion of hydrogen. To study the effect of pressure, we select the 0.1, 1, 5, 10, 15, and 20 bars. Meanwhile, we have studied the hydrogen storage capacities of the carbon honeycomb at 77 K, 153 K, 193 K, 253 K and 298 K. A high hydrogen adsorption of 4.36 wt.% is achieved at 77 K and 20 bars. The excellent mechanical properties of carbon honeycomb and its unique three-dimensional honeycomb microporous structure provide a strong guarantee for its application in practical engineering fields.


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