4,477 research outputs found
Formation of Hydrogenated Graphene Nanoripples by Strain Engineering and Directed Surface Self-assembly
We propose a new class of semiconducting graphene-based nanostructures:
hydrogenated graphene nanoripples (HGNRs), based on continuum-mechanics
analysis and first principles calculations. They are formed via a two-step
combinatorial approach: first by strain engineered pattern formation of
graphene nanoripples, followed by a curvature-directed self-assembly of H
adsorption. It offers a high level of control of the structure and morphology
of the HGNRs, and hence their band gaps which share common features with
graphene nanoribbons. A cycle of H adsorption/desorption at/from the same
surface locations completes a reversible metal-semiconductor-metal transition
with the same band gap.Comment: 11 pages, 5 figure
An Optimal Binding Number Condition for Bipancyclism
published_or_final_versio
Cascaded channel estimation technique for massive MIMO relay system
© Published under licence by IOP Publishing Ltd. This paper concerns with the cascaded channel estimation of massive multiple-input multiple-output (MIMO) relay system. In order to meet the increasing demands for high-speed wireless communication networks, massive MIMO has been recognized as one of the key technologies for the future fifth generation (5G) cellular networks. It is an advanced MIMO technique consists of a very large number of antennas at the base station and serves a smaller number of single-antenna users simultaneously. Basically, the idea of massive MIMO technique is to harvest all the advantages of conventional MIMO system in a much larger scale. To reap the benefits of massive MIMO in practice, an accurate estimation of the channel state information (CSI) is needed. In this paper, the relaying technique has been incorporated with massive MIMO system in order to increase system throughput and improve the coverage in cell-edge users. A relay node is placed in between transmitter and receiver to reduce the path loss and improve the spectral efficiency of massive MIMO system. Cascaded channel estimation technique for massive MIMO relay system is developed in this paper. The mean squared error (MSE) of the cascaded channel estimation for massive MIMO relay sytem is optimized to obtain accurate CSI
Mathematics simulation and experiments of continuous casting with strip feeding in mold
Steel strip feeding technology can reduce the degree of superheat of the molten steel, change the solidification order of the molten steel; raise the equiaxed crystal rate of the slab and improve the continuous casting quality. The paper establishes the mathematical model of heat transfer and temperature field of casting billet of steel strip feeding in continuous casting mold. Results show that if Plate Billet is 1 000 mm × 220 mm and the steel strip is 100 mm × 3 mm, feeding position of parallel is 250 mm from the narrow side. When the feeding speed is 3,6 m/min, the superheat degree can be reduced by 5 °C, and the solidification length can be reduced by 2,9 m. When the feeding speed is 6 m/min, the superheat degree can be reduced by about 9 °C, and the solidification length can be reduced by 3,7 m. The results of the test in a steel plant are in good agreement with the experimental results
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