Hubei University for Nationalities
Enshi, China

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Ma D.-Z.,Hubei University for Nationalities | Cao Y.,Beijing Normal University | Wu J.-P.,Beijing Normal University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2011

In this Letter we construct the Stückelberg holographic superconductor with Weyl corrections. Under such corrections, the Weyl coupling parameter γ plays an important role in the order of phase transitions and the critical exponents of second order phase transitions. So do the model parameters cα, α and c4. Moreover, we show that the Weyl coupling parameter γ and the model parameters cα, α, c4 which together control the size and strength of the conductivity coherence peak and the ratio of gap frequency over critical temperature ωg/Tc. © 2011 Elsevier B.V.

Zeng X.-X.,Chongqing Jiaotong University | Liu X.-M.,Hubei University for Nationalities | Liu W.-B.,Beijing Normal University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2015

Gravitational collapse of a shell of dust in noncommutative geometry is probed by the renormalized geodesic length, which is dual to probe the thermalization by the two-point correlation function in the dual conformal field theory. We find that the larger the noncommutative parameter is, the longer the thermalization time is, which implies that the large noncommutative parameter delays the thermalization process. We also investigate how the noncommutative parameter affects the thermalization velocity and thermalization acceleration. © 2015 The Authors.

Wu D.,Hubei University for Nationalities | Long M.,Shanghai JiaoTong University
ACS Applied Materials and Interfaces | Year: 2011

The visible-light-induced self-cleaning property of cotton has been realized by coating N-TiO 2 film and loading AgI particles simultaneously. The physical properties were characterized by means of XRD, SEM, TEM, XPS, and DRS techniques. The visible light photocatalytic activities of the materials were evaluated using the degradation of methyl orange. In comparison with TiO 2-cotton, the dramatic enhancement in the visible light photocatalytic performance of the AgI-N-TiO 2-cotton could be attributed to the synergistic effect of AgI and N-TiO 2, including generation of visible light photocatalytic activity and the effective electron-hole separations at the interfaces of the two semiconductors. The photocatalytic activity of the AgI-N-TiO 2-cotton was fully maintained upon several numbers of photodegradation cycles. In addition, according to the XRD patterns of the AgI-N-TiO 2-cotton before and after reaction, AgI was stable in the composites under visible light irradiation. Moreover, a possible mechanism for the excellent and stable photocatalytic activity of AgI-N-TiO 2-cotton under visible light irradiation was also proposed. © 2011 American Chemical Society.

Wu D.,Hubei University for Nationalities | Long M.,Shanghai JiaoTong University
Surface and Coatings Technology | Year: 2012

To extend the application of N-TiO 2 to substrates with low thermal resistance, N-TiO 2 sol has been successfully synthesized at low temperature by reflux method and N-TiO 2 coating on cotton fabrics has been successfully prepared in a dip-coating process. Several characterization tools, such as X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and UV-vis diffuse reflectance spectroscopy, were employed to study the phase structures, morphologies, the chemical states and optical properties of the samples. The photocatalytic properties of the prepared products were measured with the degradation of methyl orange at room temperature under visible light irradiation. In comparison with TiO 2-cotton, the remarkable enhancement in the visible light photocatalytic performance of the N-TiO 2-cotton could be attributed to the existence of N-TiO 2 with narrow band gap. The photocatalytic performances of the N-TiO 2-cotton were maintained for the cycling experiments, indicating that N-TiO 2-cotton could be used as stable and efficient visible-light-induced self-cleaning materials. © 2012 Elsevier B.V.

Li J.,Hubei University for Nationalities
Applied Mechanics and Materials | Year: 2013

For analyzing the multilayer structure of the J2EE, based on Role-Based Access Control, a model of privilege management infrastructure was designed. It was implemented after the discussion of the existing privilege management system. Moreover, the safe authority control was realized with good effect. © (2013) Trans Tech Publications, Switzerland.

In order to sweep completely the obstacle to the whole linearization of photovoltaic (PV) system with non-linear PV cell, in this paper, the voltage-current characteristic of PV cell at the maximum power point (MPP) is linearized and two linear equivalent models including Thevenin equivalent model and Norton equivalent model are proposed. On the basis of this work, the whole linearization of PV system is workable and reasonable, and then the conventional linear theories or laws can be used to study PV system conveniently. Meanwhile, in this work, the direct relationships between three linear model parameters and variable weather parameters (VWP) were found, which ensures the strong adaptation of these proposed models to the varying weather conditions. Finally, some simulation experiments verify that these proposed models are feasible and available in practical application, illustrate that the characteristics of three linear model parameters are influenced by varying weather conditions and unaffected by varying load, and show that PV system using the proposed Thevenin equivalent model has the same maximum power point tacking (MPPT) stead-state performance and similar MPPT transient-state performance with the conventional four-parameter model under fast varying weather conditions. © 2016 Elsevier Ltd

Li S.,Hubei University for Nationalities
Solar Energy | Year: 2014

In this paper, a unified model of three basic DC/DC converters is firstly proposed under certain conditions. This model is named as inductance-capacitor-diode (LCD) circuit and consisted of an inductance, a capacitor and a diode. Based on LCD circuit, a maximum power point tracking (MPPT) control strategy with variable weather parameter is proposed for photovoltaic (PV) generation systems with DC bus. In this strategy, through using LCD circuit instead of DC/DC converter, the MPPT performance of PV system is not influenced by the choice of different DC/DC converter topologies and the configuration of PV system is simplified, which makes the overall cost lower and the system integration, modularization and miniaturization more convenient. Finally, the accuracy of LCD model, and the feasibility and availability of proposed MPPT control strategy are verified by some simulated experiments conducted under random weather conditions; the effect of non-uniform weather on proposed MPPT strategy is tested by some experiments under non-uniform weather conditions; the output transient-state performance of proposed MPPT strategy is analyzed by one experiment under a varying irradiance condition and the performance comparison with conventional P&O method is made by another experiment under a given weather condition. © 2014 Elsevier Ltd.

Study on the temperature controlling optimization problem of a novel microchip level PCR instrument, a compound control scheme based on Smith predictive and adaptive Fuzzy-PID is presented. Because the temperature control system of microchip level PCR instrument is a time-varying, non-linear and pure time delay complex system, to achieve the different temperature zones rapid switching and the temperature precision controlling is easy to be affected by time delay factor, it may encounter problems such as large overshoot, and even poor stability in the control of system with time delay. In this system, Smith predictable compensation control temperature algorithm should be adopted to decrease the overshooting and oscillating, adaptive Fuzzy-PID control temperature algorithm should be adopted to solve the problem of low precision and poor capability because of the fuzzy rules roughness. The simulation results show that the Smith predictive adaptive Fuzzy-PID temperature control algorithm has the fast response, high precision temperature controlling and strong robust properties, and it can provide a reference for the intelligent temperature control system design of microchip level PCR instrument. © (2013) Trans Tech Publications, Switzerland.

Liu H.,Hubei University for Nationalities
Journal of Nanoparticle Research | Year: 2010

Iron phosphate nanorods were synthesized via a novel facile route. The structure, composition, and morphology of the prepared material were characterized by X-ray diffraction (XRD) and transmission electron microscope (TEM), respectively. The diffraction lines were indexed to the hexagonal structure. The diameter of these nanorods is about in the range of 20-30 nm and the length 50-100 nm. The preferential growth direction of the prepared material was the [100]. The reaction mechanism for the synthesis of FePO4 nanorods was also primarily discussed. Compared to the bulky and the irregular nanoparticles, the nanometer ones will be more fascinating for application in many areas. © 2010 Springer Science+Business Media B.V.

To improve the tracking speed of maximum power point (MPP) of photovoltaic (PV) system, some maximum power point tracking (MPPT) algorithms or their improved algorithms have been studied in depth. However, these algorithms are usually the improvement for a certain MPPT method, now there still exists no common method for improving the rapidity of the MPP tracking. To solve this question, in this paper, the conceptions of load-variable-weather-parameter (RVWP) optimization interval and variable-weather-parameter (VWP) optimization interval are proposed. Meanwhile, on the basis of them, a VWP optimization strategy, which can optimize the tracking speed of most MPPT algorithms, is proposed. In this strategy, the control signal of PV system has been quickly contracted within RVWP interval or VWP interval before a MPPT method which will implement the MPP tracking is operated. Therefore, the essence of this strategy is that the MPP tracking speed is increased by contracting the optimizing range-in other words, the global optimization is converted into local optimization. Finally, in this paper, the conventional perturb and observe (P&O) method is selected as the optimized object to study the MPP tracking speed under constant load, changing load, constant weather and changing weather conditions. The results of simulated experiments show that the MPP tracking speed can be greatly optimized by VWP optimization strategy with RVWP interval in any case and can be optimized by VWP optimization strategy with VWP interval in most cases, and that the output power stability can be also optimized by proposed optimization strategy for PV system with output power oscillating. © 2014 Elsevier Ltd.

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