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510 results on '"Lei, X. L."'

164. Linear magnetotransport in monolayer MoS2.

Author

Wang, C. M. and Lei, X. L.

Subjects
*MONOMOLECULAR films, *MOLYBDENUM, *SHUBNIKOV-de Haas effect, *MAGNETOPHONON effects, *MAGNETORESISTANCE, *MAGNETIC field effects, *PHONONS
Abstract

A momentum balance equation is developed to investigate the magnetotransport properties in monolayer molybdenum disulphide when a strong perpendicular magnetic field and a weak in-plane electric field are applied simultaneously. At low temperature, in the presence of intravalley impurity scattering, Shubnikov–de Haas oscillation shows up accompanied by a beating pattern arising from large spin splitting and its period may halve due to the high-order oscillating term at large magnetic field for samples with ultrahigh mobility. In the case of intervalley disorders, there exists a magnetic-field range where the magnetoresistivity almost vanishes. For a low-mobility layer, a phase inversion of oscillating peaks is acquired in accordance with recent experiment. At high temperature when Shubnikov–de Haas oscillation is suppressed, the magnetophonon resonances induced by both optical phonons (mainly due to homopolar and Frohlich modes) and acoustic phonons (mainly due to intravalley transverse and longitudinal acoustic modes) emerge for a suspended system with high mobility. For the single layer on a substrate, another resonance due to surface optical phonons may occur, resulting in a complex behavior of the total magnetoresistance. The beating pattern of magnetophonon resonance due to optical phonons can also be observed. However, for a nonsuspended layer with low mobility, the magnetoresistance oscillation almost disappears and the resistivity increases with field monotonically. [ABSTRACT FROM AUTHOR]

Published
2015
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188. Numerical Simulation of the Behavior of Falling Films on Horizontal Plain Tubes.

Author

Lei, X. L. and Li, H. X.

Subjects
*COMPUTER simulation, *SIMULATION methods & models, *MATHEMATICAL models, *EVAPORATION (Chemistry), *ELECTROMECHANICAL analogies
Abstract

In this paper, a numerical simulation is performed in order to reveal the evaporation heating transfer mechanism of the falling-film of water on the outer wall of horizontal tubes, and the influence of gas-water-solid contact angles on the film distribution on the tube is mainly addressed. The simulation is performed by solving the motion equation of the fluid on fixed three-dimensional (3D) grid systems, and the so-called volume of fluid (VOF) method is employed to handle the movement of interface between the liquid and the vapor phase. The numerical results are compared with that of a simplified model and also with the experimental recordings obtained in visualization experiments conducted with tubes made of different materials, and it is shown that the numerical results are in very good agreement with the experimental observation of the falling films, indicating that the numerical methods applied in the present study is correct and accurate. Based on the numerical results, effects of the contact angle, the flow rate, the tube diameter and the liquid feeder height on the falling film behavior are discussed. Generally, the film width increases along with the increase of flow rate or the liquid feeder height, while variation of the film thickness exhibits different features at different conditions, and the contact angle is one of the major factors governing the behavior of the falling films. [ABSTRACT FROM AUTHOR]

Published
2010
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