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Dou C.-X.,Yanshan University | Liu B.,Hunan University of Technology | Liu B.,Australian National University
IEEE Transactions on Smart Grid | Year: 2013

This paper studies the smart control issue for an autonomous microgrid in order to maintain the secure voltages as well as maximize economic and environmental benefits. A control scheme called as multi-agent based hierarchical hybrid control is proposed versus the hierarchical control requirements and hybrid dynamic behaviors of the microgrid. The control scheme is composed of an upper level energy management agent, several middle level coordinated control agents and many lower level unit control agents. The goals of smart control are achieved by designed control strategies. The simulations are given to demonstrate the effectiveness of proposed smart control for an autonomous microgrid. © 2010-2012 IEEE.

Chen Z.,Hunan University of Technology
Neural Computing and Applications | Year: 2013

In this paper, a shunting inhibitory cellular neural network with leakage delays and continuously distributed delays of neutral type is considered. Some sufficient conditions are established to ensure that all solutions of the networks converge exponentially to zero point, which are new and complement of previously known results. © 2012 Springer-Verlag London.

Dou C.-X.,Yanshan University | Liu B.,University of Sydney | Liu B.,Hunan University of Technology
International Journal of Electrical Power and Energy Systems | Year: 2014

Due to an increased penetration of distributed energy resources, as well as more uncertain operating environment, etc., present distribution power system is facing many challenges. For improving the performance regarding dynamic stability, self-healing, security, as well as economical and environmental benefit, this paper proposes a hierarchical management and control strategy for the high-penetrated distribution grid based on multi-agent systems structure via intelligent switching of operating mode. Corresponding to the complex hybrid behaviors, the hierarchical control scheme is designed as a three-level decentralized coordinated hybrid control. The simulation studies certify that the hierarchical hybrid control is effective and feasible to deal with comprehensive problems of high-penetrated distribution grids. © 2013 Elsevier Ltd. All rights reserved.

Zeng L.,Jiangxi science and Technology Normal College | Liu G.,Jiangxi science and Technology Normal College | Yang D.,Hunan University of Technology | Ji X.,Doppler Electronic Technologies Company Ltd
Optics Express | Year: 2012

We present a 3D-visual laser-diode-based photoacoustic imaging (LD-PAI) system with a pulsed semiconductor laser source, which has the properties of being inexpensive, portable, and durable. The laser source was operated at a wavelength of 905 nm with a repetition rate of 0.8 KHz. The energy density on the sample surface is about 2.35 mJ/cm2 with a pulse energy as low as 5.6 μJ. By raster-scanning, preliminary 3D volumetric renderings of the knotted and helical blood vessel phantoms have been visualized integrally with an axial resolution of 1.1 mm and a lateral resolution of 0.5 mm, and typical 2D photoacoustic image slices with different thickness and orientation were produced with clarity for detailed comparison and analysis in 3D diagnostic visualization. In addition, the pulsed laser source was integrated with the optical lens group and the 3D adjustable rotational stage, with the result that the compact volume of the total radiation source is only 10 × 3 × 3 cm3. Our goal is to significantly reduce the costs and sizes of the deep 3D-visual PAI system for future producibility. © 2012 Optical Society of America.

Xie Z.-X.,Hunan University of Technology | Chen K.-Q.,Hunan University of Technology | Duan W.,Tsinghua University
Journal of Physics Condensed Matter | Year: 2011

The thermal transport properties by phonons in zigzag graphene nanoribbons with structural defects are investigated by using nonequilibrium phonon Green's function formalism. We find that the combined effect of the edge and local defect plays an important role in determining the thermal transport properties. In the limit T → 0, the thermal conductance approaches the universal quantum value 3K0(K0 = π2k2 B T/3h) even when structural defects are presented in graphene nanoribbons. The thermal transport shows a noticeable transformation from quantum to classical features with increasing temperature in the system. A suggestion to tune the thermal conductance by modulating structural defects and the ribbon width in graphene nanoribbons is presented. © 2011 IOP Publishing Ltd.

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