Wuhan University of Science and Technology is a public, comprehensive, research university located in Wuhan, the capital of Hubei province, China. It is a key university co-administered by the Chinese Ministry of Education and Hubei province. Wikipedia.
Li X.H.,Wuhan University of Science and Technology |
Hong S.H.,Hanyang University
Energy | Year: 2014
Demand response algorithms can cut peak energy use, driving energy conservation and enabling renewable energy sources, as well as reducing greenhouse-gas emissions. The use of these technologies is becoming increasingly popular, especially in smart-grid scenarios. We describe a home-to-grid demand response algorithm, which introduces a UEP ("user-expected price") as an indicator of differential pricing in dynamic domestic electricity tariffs, and exploits the modern smart-grid infrastructure to respond to these dynamic pricing structures. By comparing the UEP with real-time utility price data, the algorithm can discriminate high-price hours and low-price hours, and automatically schedule the operation of home appliances, as well as control an energy-storage system to store surplus energy during low-price hours for consumption during high-price hours. The algorithm uses an exponential smoothing model to predict the required energy of appliances, and uses Bayes' theorem to calculate the probability that appliances will demand power at a given time based on historic energy-usage data. Simulation results using pricing structures from the Ameren Illinois power company show that the proposed algorithm can significantly reduce or even eliminate peak-hour energy consumption, leading to a reduction in the overall domestic energy costs of up to 39%. © 2013 Elsevier Ltd.
Hu J.,Wuhan University of Science and Technology |
Zhu Z.Q.,University of Sheffield
IEEE Transactions on Power Electronics | Year: 2011
This paper investigates the switching patterns of direct power control (DPC) strategies for three-phase grid-connected voltage-sourced dc-ac converters. The instantaneous variation rates of active and reactive powers by applying each converter voltage vector in 12 different sectors are deduced. In terms of hysteresis look-up-table DPC, based on the power variation rates, modified switching tables are presented to alleviate the active power pulsations, and an asymmetrical hysteresis controller is proposed for active power control to eliminate its steady-state errors. As to predictive DPC, according to the power variation rates, the cause is identified to that the values of the predicted duration times for the auxiliary active voltage vector become negative. Consequently, to solve this problem, two new alternative vector sequences are proposed and compared. A simple compensation method is further added to the basic control scheme of predictive DPC to deal with grid voltage unbalances. Experimental results on a 1.5-kVA grid-connected dc-ac converter are presented to validate the feasibility of the improved switching patterns and the unbalanced compensation method on the DPC strategies for dc-ac converters. © 2006 IEEE.
Deng C.,Wuhan University of Science and Technology
Journal of Alloys and Compounds | Year: 2013
Monophase Al4O4C ceramic powder was synthesized using a mixture of a-alumina, carbon black and aluminum powders as raw materials. The effects of different starting compositions and raw materials ratio on the phase transformation and micromorphology of Al4O4C were investigated. The results indicated that a-alumina, carbon black and aluminum powders was more appropriate as raw materials, and 20 mol% excess of aluminum resulted in single phase Al4O4C. Al2OC would occur if excessive carbon black was used. The Al content was found to have a significant effect on the microstructure of synthesized Al4- O 4C. Al4O4C added to the MgO-C refractory initially reacts with CO to form Al2O3 and C. After the reaction, the formed Al2O3 will further react with MgO to form MgAl2O4. The above reaction processes can form protective layers on the surfaces of the refractories, which inhibit the oxidation of the refractories. © 2013 Elsevier B.V. All rights reserved.
Yu X.-X.,Wuhan University of Science and Technology |
Wang Y.-H.,Wuhan University of Science and Technology
Optics Express | Year: 2014
Silver nanoparticles synthesized in a synthetic sapphire matrix were fabricated by ion implantation using the metal vapor vacuum arc ion source. The optical absorption spectrum of the Ag: Al2O3 composite material has been measured. The analysis of the supercontinuum spectrum displayed the nonlinear refractive property of this kind of sample. Nonlinear optical refraction index was identified at 800 nm excitation using the Kerrlens autocorrelation (KLAC) technique. The spectrum showed that the material possessed self-defocusing property (n2 = -1.1 × 10 -15 cm2/W). The mechanism of nonlinear refraction has been discussed. © 2014 Optical Society of America.
Li F.,Wuhan University of Science and Technology
International Journal of Sensor Networks | Year: 2011
In this paper, the uplink scenario of multi-user cooperative network is considered, in which the resource is allocated to the users with the balance of the trade-off between system capacity and user fairness. Proportional fairness was considered, which imposed a set of nonlinear constraints into the optimisation problem. We show that the optimisation problem is formulated as a mixed binary integer programming problem, which is hard to find the global optimum in terms of computational complexity. For practise implementation, we decomposed the optimisation problem into two sub-problems of opportunistic relaying strategy and power allocation. First, the opportunistic relay selection strategy is given by making use of the equivalent channel power gain. Second, a low-complexity power allocation scheme is proposed. The simulation result shows that the proposed scheme can both improve the system throughput and ensure the fairness. © 2011 Inderscience Enterprises Ltd.
Lu J.-D.,Wuhan University of Science and Technology
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2010
We report on a theoretical study of spin-dependent electron transport in a magnetic nanostructure with the δ-doping. It is revealed that the transmission probability, the electron conductance and the spin-polarization obviously depend on the weight of the δ-doping. It is also revealed that the transmission probability and the spin-polarization (PT) both show a periodic profile with the increase of the length L2. These interesting phenomena will be more helpful for understanding the experimental physical phenomena in δ-doping and for making new types of devices. © 2010.
Ye H.,Wuhan University of Science and Technology
Zeitschrift fur Angewandte Mathematik und Physik | Year: 2015
In this paper, we study the existence of critical points for the following functional constrained on (Formula Presented.),where N = 1, 2, 3 and a, b > 0 are constants. The constraint problem is L2-critical. We showed that I(u) has a constraint critical point with a mountain pass geometry on Sc if (Formula Presented.), where Q is the unique positive radial solution of (Formula Presented.), I(u) has no critical point on Sc, and we proved the existence of minimizers for a new perturbation functional on Sc:(Formula Presented.). © 2014, Springer Basel.
Hou T.P.,Wuhan University of Science and Technology |
Wu K.M.,Wuhan University of Science and Technology
Acta Materialia | Year: 2013
The influence of a high magnetic field on carbide precipitation during the tempering of a 2.25 Cr-Mo steel was investigated by means of transmission electron microscopy. As-quenched specimens were tempered at 200, 550 and 700 °C for various times in the absence and presence of a 12 T magnetic field. Experimental results indicate that the applied high magnetic field effectively promotes the precipitation of M23C6 carbides at low temperature (200 °C) and M7C3 and M23C 6 carbides at intermediate temperature (550 °C). The increased Fe content in the M23C6 and M7C3 carbide significantly increases the magnetization. The magnetic Gibbs free energy, which influenced the alloy carbide precipitation behavior, was considered to be mainly determined by the intrinsic magnetization energy for M23C6 and M7C3 carbides. With the increase of the tempering temperature (700 °C), there was no pronounced effect of the high magnetic field on the precipitation sequence and the concentration of substitutional solute atoms in paramagnetic carbides. The investigation of alloy carbide precipitation under high magnetic fields could contribute to a better understanding of phase transformation of alloy carbides and to the heat treatment and fabrication of heat-resistant steels. © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Fang Y.,Wuhan University of Science and Technology
Advances in Information Sciences and Service Sciences | Year: 2011
In this paper, we investigate the multiple attribute group decision making (MAGDM) problems for for evaluating the E-commerce risk with uncertain linguistic information. We utilize the uncertain linguistic weighted averaging (ULWA) operator to aggregate the uncertain linguistic information corresponding to each alternative and get the overall value of the alternatives, then rank the alternatives and select the most desirable one(s) by using the formula of the degree of possibility for the comparison between two uncertain linguistic variables. Finally, an illustrative example is given.
Tian J.,Wuhan University of Science and Technology |
Chen L.,Wuhan University of Science and Technology
Signal Processing | Year: 2012
Multi-focus image fusion aims to combine a set of images that are captured from the same scene but with different focuses for producing another sharper image. The critical issue in the design of multi-focus image fusion algorithms is to evaluate the local content information of the input images. Motivated by the observation that the marginal distribution of the wavelet coefficients is different for images with different focus levels, a new statistical sharpness measure is proposed in this paper by exploiting the spreading of the wavelet coefficients distribution to measure the degree of the images blur. Furthermore, the wavelet coefficients distribution is evaluated using a locally adaptive Laplacian mixture model. The proposed sharpness measure is then exploited to perform adaptive image fusion in wavelet domain. Extensive experiments are conducted using three sets of test images under three objective metrics to demonstrate the superior performance of the proposed approach. © 2012 Elsevier B.V. All rights reserved.