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Batch synthesis of transfer-free graphene with wafer-scale uniformity

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Nano Research 2020年第6期13卷 1564-1570页

作者： Bei Jiang Qiyue Zhao Zhepeng Zhang Bingzhi Liu Jingyuan Shan Liang Zhao Mark H.Rümmeli Xuan Gao Yanfeng Zhang Tongjun Yu Jingyu Sun Zhongfan Liu Center for Nanochemistry(CNC) Beijing Science and Engineering Center for NanocarbonsCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing100871China State Key Laboratory for Artificial Microstructures and Mesoscopic Physics School of PhysicsPeking UniversityBeijing100871China College of Energy Soochow Institute for Energy and Materials Innovations(SIEMIS)Key Laboratory of Advanced Carbon Materials and Wearable Energy Technologies of Jiangsu ProvinceSoochow UniversitySuzhou215006China Beijing Graphene Institute(BGI) Beijing100095China

Scalable synthesis of transfer-free graphene over insulators offers exciting opportunity for next-generation electronics and ***,rational design of synthetic protocols to harvest wafer-scale production of directly grown graphene still remains a daunting *** we explore a batch synthesis of large-area graphene with wafer-scale uniformity by virtue of direct chemical vapor deposition(CVD)on *** a controllable CVD approach allows to synthesize 30 pieces of 4-inch graphene wafers in one batch,affording a low fluctuation of optical and electrical *** fluid dynamics simulations reveal the mechanism of uniform growth,indicating thermal field and confined flow field play leading roles in attaining the batch *** resulting wafer-scale graphene enables the direct utilization as key components in optical *** method is applicable to other types of insulating substrates(e.g.,sapphire,SiO2/Si,Si3N4),which may open a new avenue for direct manufacture of graphene wafers in an economic fashion.

关键词： graphene batch synthesis direct chemical vapor deposition(CVD) uniformity wafer-scale confined flow

STUDIES ON THE LAW OF LAMINAR HELICAL flow OF POWER-LAW FLUID IN ECCENTRIC ANNULI

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Applied Mathematics and Mechanics(English Edition) 1993年第7期14卷 627-634页

作者：李帮达刘永健张景富 Daqing Petroluem Institute Anda Helongjiang

The flow of mud under a constant axial pressure gradient in eccentric annuli was studied extensively in this paper. Assumed that the inner wall was rotating at a constant angular velocity, then the constitutive equation of power law fluid and the equation of motion were given. The expressions of apparent viscosity, velocity, flow rate and pressure loss were obtained. In Some numerical results were given by alternation-substitution method. The conclusions are that the viscosity difference between wide and narrow clearance is reduced with increasing the rotation of inner cylinder and/or decreasing the eccentric distance. The flow rate will be increased with increasing the rotation of inner cylinder and eccentric distance, etc.. The pressure loss in eccentric flow is quite large than in concentric axial flow. The results are useful for calculating hydraulic parameters in drilling engineering.

关键词： confined flow Laminar flow Well drilling

ANALYTICAL SOLUTIONS OF THE HELICAL flow OF NONNEWTONIAN FLUID IN ECCENTRIC ANNULAR SPACE

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Applied Mathematics and Mechanics(English Edition) 1994年第7期15卷 657-670页

作者：张海桥吴继周 The Department of Basic Courses Daging Petroleum Institute Heilongjiang

Many problems in petroleum and chemical industry can be reduced to the solution of the helical flow of non-Newtonian fluid in eccentric annular space. The laminar helical flows of the power law fluid and Bingham fluid in eccentric annular space were studied. An approximate analytical solution was obtained by the infinite subdivision method, namely, the eccentric flow was replaced by the infinite concentric flows. Then, the expressions for apparent viscosity distribution, velocity distribution and the flow rate were derived for the power law fluid and the Bingham fluid respectively. In addition, the expressions for pressure drop and stability parameter were also given. It is concluded that this method is much easier to use and more accurate than the method which solves the equations directly. The results are useful for the drilling technology of oil industry, etc.

关键词： Boundary value problems confined flow Differential equations Laminar flow Non Newtonian liquids

SHEARING flow NEAR A BYPASS WITH A BALL IN IT

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Applied Mathematics and Mechanics(English Edition) 1996年第1期17卷 25-28页

作者：陈耀松马新民梁国平戴民 Dept. of Mechanics Peking Univ. Beijing P. R. China Inst. of Math. Academia Sinica Beijing P. R. China

This article contributes to the variation of a shearing flow near the entrance of a bypass with a ball in it. It was assumed that the fluid is incompressible, the flow is steady with small Reynolds number, and at a distance far from the entrance there is an uniform shearing flow. In order to fit in with a more complicated geometry, the finite element method was used. Especially, the automatic FEM Code Composition System was used. This method reduces computing work tremendously.

关键词： confined flow Filtration Finite element method Laminar flow