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Zhang R.,Kaifeng University | Liu N.,Kaifeng University
Mathematical Methods in the Applied Sciences | Year: 2017

Optical vortices as topological objects exist ubiquitously in nature. In this paper, we use the principle of variational method and mountain pass lemma to develop some existence theorems for the stationary vortex wave solution of a coupled nonlinear Schrödinger equations, which describe the possibility of effective waveguiding of a weak probe beam via the cross-phase modulation-type interaction. The main goal is to obtain a positive solution, of minimal action if possible, with all vector components not identically zero. Additionally, as demanded by beam confinement, we prove the exponential decay of the soliton amplitude at infinity. © 2017 John Wiley & Sons, Ltd.


LaFeO3 was synthesized via a simple gel-combustion method at the calcination temperatures of 200-400°C. The X-ray diffraction characterization indicated that the products synthesized at 200-400°C were all pure perovskite phase LaFeO3. The scanning electron microscopy images revealed that the LaFeO3 synthesized at 200°C had a porous nanostructure, but became a solid nanostructure at 400°C. The nitrogen adsorption measurements suggested that the specific surface area of LaFeO3 increased with the lowering of the calcination temperature. The UV-vis diffuse reflection spectra showed that the LaFeO3 synthesized at 200°C exhibited the strongest absorption of visible-light. The photocatalytic experiments demonstrated that as the calcination temperature was lowered, the resultant LaFeO3 exhibited obviously enhanced photocatalytic activity in reduction of Cr(VI) in aqueous solution under visible-light (wavelength longer than 420nm) irradiation. This work can enrich our knowledge on the synthesis and photoabsorption properties of porous nanostructure LaFeO3, and contribute to the application of LaFeO3 nanomaterials in treating the wastewaters contaminated by highly toxic and intractable Cr(VI). © 2017 Elsevier B.V.


Wireless sensor networks with node calculation ability is weak, node power (battery provides) Limited, routing algorithm of wireless sensor networks should be the energy saving and simple algorithm. Ant colony algorithm shows good search results in the discrete solution space. This paper improves the ant colony optimization algorithm. The paper presents analysis of routing protocols for wireless sensor networks based on improved ant colony optimization algorithm, and the simulation results verify the effectiveness of the improved algorithm. © (2014) Trans Tech Publications, Switzerland.


He T.,Sun Yat Sen University | Hu Z.S.,Kaifeng University | Li J.L.,Sun Yat Sen University | Yang G.W.,Sun Yat Sen University
Journal of Physical Chemistry C | Year: 2011

We have presented a comprehensive investigation for the geometric, energetic, and electronic structures of the rutile TiO2 nanowire (NW) and nanotube (NT) by the first-principles calculations accompanied with the crystal orbital overlap population and the wave function analysis. Taking into account the surface interactions, we found that the geometry and stability of TiO2 NWs and NTs greatly depend on the surface structure with the size decreasing, which demonstrates the forming shape and structure. The competition between the surface-bonding effect and the quantum-confinement effect induces the oscillation behavior and the direct-indirect transition of the band gap of TiO2 NWs and NTs. These findings not only provide a new insight into the fundamental understanding of TiO2 nanostructures but also provide useful information to design TiO2 nanostructures for different applications. © 2011 American Chemical Society.


Li J.L.,Sun Yat Sen University | Hu Z.S.,Kaifeng University | Yang G.W.,Sun Yat Sen University
Chemical Physics | Year: 2012

By theoretical analysis, we have explored the feasibility of functionalizing boron fullerene (B 80) by adsorbing Mg atoms for the application as hydrogen storage nanomaterials. Our results show that due to the charge transfer from Mg to B atoms Mg atoms reside above the pentagonal faces of the B 80 cage. The electric field induced around the positive charged Mg atoms polarizes H 2 molecules, and the resulting binding is strong enough to adsorb H 2 without dissociation. Further calculations indicated that the 12Mg-decorated-B 80 has a high hydrogen storage capacity storing up to 96 H 2 molecules with an ideal binding energy of 0.20 eV/H 2 according to the approximation of GGA and 0.5 eV/H 2 according to LDA, corresponding to a hydrogen uptake of 14.2%. This suggested a possible method of engineering new structure for high-capacity hydrogen storage materials with the reversible adsorption and desorption of hydrogen molecules. © 2011 Elsevier B.V. All rights reserved.


Beginning with the increasingly serious situation facing human society, it describes the origin and meaning of ecological circular economy; after that, it focuses on the three main principles of the eco-circular economy, they are reduction, reuse and recycle principles. Then, it analyzes the eco-circular economy further from the angle of industrial technology and economic dimensions, summarizes the barriers to the development of eco-circular economy. Finally, the paper elaborates a number of measures in the establishment of eco-circular economy. © (2012) Trans Tech Publications.


Wang Y.,Henan University | Wang Y.,Kaifeng University | Feng C.,Henan University | Zhang M.,Henan University | And 2 more authors.
Applied Catalysis B: Environmental | Year: 2011

Three kinds of precursors, nanotubular titanic acid (denoted as NTA), raw P25-TiO2 and novel-TiO2, were separately used to prepare visible light active N-doped TiO2 samples by annealing in flowing NH3, aiming to reveal the determinative factors on visible light response. The physicochemical properties of resultant N-doped TiO2 samples were investigated by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), diffuse reflectance spectra (DRS), and electron spin resonance (ESR). The visible light photocatalytic activity of the three kinds of N-doped samples was compared by monitoring the photocatalytic oxidation of propylene. It was found that N-doped TiO2 catalyst obtained by using NTA as the precursor possessed the highest photocatalytic activity. The absorption edge observed in the visible spectral region of 2.34-2.53eV is closely related with single-electron-trapped oxygen vacancy (denoted as SETOV, i.e., F+ color centers), while another absorption edge at 2.95-3.10 is assigned to the intrinsic absorption. The visible light sensitization of N-doped TiO2 was due to the formation of SETOV in NH3-treatment process, and doped-N played a role in preventing photogenerated electrons and holes from recombination, resulting in visible light photocatalytic activity. N-doped TiO2 samples made from different precursors had different concentrations of SETOV and hence different visible light photocatalytic performance. © 2011 Elsevier B.V.


Liu Z.,Kaifeng University
Mathematical Methods in the Applied Sciences | Year: 2016

In this paper, we study the following biharmonic equation Δ2u=K(|y|)up,u>0,inB1(0),u=Δu=0,on∂B1(0), where p=N+4N-4, K(1) > 0,K'(1) > 0, B1(0) is the unit ball in RN(N≥6). We show that the aforementioned problem has infinitely many peak solutions, whose energy can be made arbitrarily large. © 2016 John Wiley & Sons, Ltd.


Gao M.-Y.,Kaifeng University
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2012

Recycling of feedback renewable electricity of braking motors is an important approach to save energy. In this paper, the architecture of an energy storage system is analyzed to get the equivalent circuit firstly. Then, the switching system model is established for the bi-directional DC-DC converter of the energy storage system, and Lyapunov function is constructed to get the system switch rules. Simulation result shows that with the control of the switching rules, the model can fully absorb and utilize the feedback electrical energy of the motor, keep DC bus voltage steady, and save system energy.


Chen Y.,Kaifeng University
WIT Transactions on Information and Communication Technologies | Year: 2014

In this paper, the author gives an introduction to a security system for the student apartment management of higher learning schools. The author carries out a detailed analysis on the control principle of this system as well as its composition modules, and introduces the software design of the system at the same time. This system is reliable, simple, economical, and feasible, and can be applied widely in the student apartment security management of higher learning schools. © 2014 WIT Press.

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