Composition Dependent Ionic Conductivity in ß''-Alumina

1990 ◽  
Vol 210 ◽  
Author(s):  
C. Lane Rohrer ◽  
G. C. Farrington

AbstractMolecular dynamics simulations were carried out in an attempt to reproduce and explain the differing composition dependencies of the ionic conductivities of Na(I)-Ba(II)- and Na(I)-Sr(II)- ß' '-alumina. Impedance spectroscopy measurements of Na1.67-2xBaxMg0.67Al10.33O17, where x = 0.0 - 0.835, showed a distinct minimum in the conductivity when x = 0.67, or 80% exchange of Ba(II) for Na(I). Evidence for mobile cation ordering at that composition was seen in the simulation results and the general change in conductivity with Ba(II) content was reproduced rather well. The results of a similar experimental study of Na(I)-Sr(II)-ß' '-alumina did not show a minimum in the conductivity, but our simulations incorrectly predicted the Sr(II) system to behave in the same fashion as the Ba(II) system. Possible reasons for this discrepancy are suggested, including problems with transferring potentials between oxides and the influence of absorbed water on the experimental results.

2012 ◽  
Vol 1407 ◽  
Author(s):  
Andrew L. J. Pang ◽  
Viacheslav Sorkin ◽  
Yong-Wei Zhang

ABSTRACTWe studied the self-assembly mechanisms of Graphene Nanoribbon (GNR) with unsaturated edges and demonstrated the ability of GNR to self-assemble into novel stable structures. We proposed three mechanisms which dictate the self-assembly evolution of GNR with unsaturated edges. Using the Adaptive Intermolecular Reactive Empirical Bond-Order (AIREBO) potential, we performed molecular dynamics simulations on initially-planar GNRs with unsaturated edges. The simulation results showed that the self-assembly mechanisms and final conformations of the GNRs correlate well with the proposed GNR self-assembly mechanisms. Furthermore, the simulations also showed the ability of a narrow GNR to self-assemble into various nanostructures, such as tapered graphene nano-rings and graphene nanoscrolls with an embedded nanotube.


Polymer ◽  
2017 ◽  
Vol 113 ◽  
pp. 39-45 ◽  
Author(s):  
Alina A. Sofronova ◽  
Diana B. Evstafyeva ◽  
Vladimir A. Izumrudov ◽  
Vladimir I. Muronetz ◽  
Pavel I. Semenyuk

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Enrique Lima ◽  
María Elena Villafuerte-Castrejón ◽  
José Saniger ◽  
Victor Lara ◽  
Jorge E. Sánchez-Sánchez ◽  
...  

X-ray diffraction,27Al MAS NMR, and FTIR spectra along with results of molecular dynamics simulations were used to characterise LaxEu1−xAlO3perovskites forx=0.3,  0.1. Experimental and simulation results show that local changes in the perovskite-like structure can be achieved as lanthanum ions substitute europium ones. The introduction of La3+ions in the EuAlO3parent causes an increase in the mobility of oxygen network.


2020 ◽  
Vol 127 (14) ◽  
pp. 145304 ◽  
Author(s):  
Q. Bizot ◽  
O. Politano ◽  
A. A. Nepapushev ◽  
S. G. Vadchenko ◽  
A. S. Rogachev ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document