Recently, a two-dimensional (2D) oxocarbon monolayer, graphether, is arousing extensive attentions owing to the excellent electrical properties. In this work, we calculate lattice thermal conductivities (k) of graphether and graphene...

Recently, two-dimensional transition metal dichalcogenide (TMDC) monolayers have stirred much attention owing to their excellent physical properties. In the present study, we systematically investigate the thermoelectric properties of different WS2-WSe2...

This paper presents an exDerimental study on pioelining of Shanjiasi heavy crude oil as oil-in-water emulsions. Viscosity reductions of more than three orders of magnitude were achieved in laboratory by emulsification. Field trials were then made in three 4-in. gathering lines 101, 160 and 241 meters long respectively. A chemical solution was injected into the gathering line at the wellhead. Drag reductions of 40-80% were achieved provided that the formed emulsions had an injected water fraction of 0.2-0.4 and the chemical concentration was at 0.35-0.5% (based on injected water). It was also found that drag reduction was more significant at a low temperature and for a highly viscous heavy oil. A big difference existed between rheologi" cal data obtained from the field trials and those from laboratory experiments, and possible reasons were discussed.

Recently, two-dimensional (2D) group III monolayer XP3 (X = Al, Ga, and In) have attracted great attention due to their excellent physical properties. We systematically investigate the thermoelectric (TE) properties of monolayer XP3 by combining first-principles calculations and Boltzmann transport theory. It can be confirmed that monolayer XP3 are dynamically stable structures and semiconductors with indirect band gaps. The carrier mobilities of monolayer XP3 are calculated by using the deformation potential theory. Besides, at 300 K, the power factors of n-type doping AlP3, GaP3, and InP3 are 35.51, 12.47, and 18.41 mW m−1 K−2, respectively. Moreover, the phononic transport properties of all monolayers are evaluated, and lattice thermal conductivities of AlP3, GaP3, and InP3 are 0.60, 4.47, and 1.93 W m−1 K−1 at 300 K, respectively, which can be explained by small phonon group velocity and ultra-low phonon lifetime. Finally, the outstanding TE figure of merits (ZT) of AlP3, GaP3, and InP3 with n-type doping are 8.33, 2.09, and 4.22 at 700 K, respectively, which establishes a new record of TE performance of 2D materials. Our work clearly shows the prominent properties of novel 2D material XP3 and will further promote technological development in the TE field.

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