Yang Y.,Wuhan University of Technology |
Zhang G.,Wuhan University of Technology |
Xu W.,Ship Research Institute
Journal of Colloid and Interface Science | Year: 2012
In this study, we prepared a new visible light induced plasmonic photocatalyst AgAgClTiO 2/rectorite using a facile deposition-photoreduction method. The catalysts were characterized using X-ray diffraction (XRD), UV-visible diffused reflectance spectra (UV-vis DRS), Raman spectra, high-resolution transmission electron microscopy (HRTEM), and X-ray photoelectron spectroscopy (XPS). The as-prepared AgAgClTiO 2/rectorite powders exhibited an efficient photocatalytic activity for the degradation of acid orange (ARG) and 4-nitrophenol (4-NP) under visible light irradiation (λ>400nm). Moreover, the mechanism suggested that the high photocatalytic activity is due to the charge separation and the surface plasmon resonance of metallic Ag particles in the region of visible light. The active species measurements suggested that HO is not the dominant photooxidant. Direct hole transfers and O2- were involved as the active species in the photocatalytic reaction. © 2012 Elsevier Inc.
Zhang G.,Wuhan University of Technology |
He Z.,Wuhan University of Technology |
Xu W.,Ship Research Institute
Chemical Engineering Journal | Year: 2012
In this work, the sorption of fluoride on a novel zirconium-modified-Na-attapulgite (Zr-A) adsorbent was studied. The adsorbent was characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM) with EDAX analysis, X-ray photoelectron spectroscopy (XPS) and pH ZPC measurement. Physico-chemical parameters such as adsorbent dose, pH, initial fluoride concentration, temperature, equilibrium contact time and co-existing anions were studied in a series of batch adsorption experiments. The fluoride adsorption by the Zr-A adsorbent agreed well with the Langmuir model. The maximum adsorption capacity of the adsorbent is about 24.55mg/g. The fluoride adsorption kinetics over the adsorbents was well described by the pseudo-second-order kinetic model. After six regeneration cycles, the Zr-A adsorbent still showed high adsorption capacity. Finally, possible defluoridation and regeneration mechanisms were proposed. © 2011 Elsevier B.V.
Li M.-H.,Central China Normal University |
Yang H.-L.,Central China Normal University |
Hou X.-W.,Central China Normal University |
Tian Y.,Huazhong University of Science and Technology |
Hou D.-Y.,Ship Research Institute
Progress in Electromagnetics Research | Year: 2010
In this paper, we present the design, simulation, and measurement of a dual-band metamaterial absorber in the microwave region. Simulated and experimental results show that the absorber has two perfect absorption points near 11.15GHz and 16.01GHz. Absorptions under different polarizations of incident EM waves are measured with magnitude of over 97% at low-frequency peak and 99% at high-frequency peak respectively. Current distribution at the dual absorptive peaks is also given to study the physical mechanism of power loss. Moreover, it is verified by experiment that the absorptions of this kind of metamaterial absorber remain over 90% at the low-frequency peak and 92% at the high-frequency peak with wide incident angles ranging from 0° to 60° for both transverse electric wave and transverse magnetic wave.
Zhang A.-M.,Harbin Engineering University |
Yang W.-S.,Ship Research Institute |
Huang C.,China Academy of Engineering Physics |
Ming F.-R.,Harbin Engineering University
Computers and Fluids | Year: 2013
Underwater explosion detonated by column charge can generate exceedingly high-pressure shock wave, bubble pulsing and high-speed jet formed by bubble. Its physical course involves many complicated problems such as transient state, high temperature and high pressure, large distortion and multi-medium flow. For this reason, axisymmetric Smoothed Particle Hydrodynamics (SPHs) numerical model was established combined with Boundary Element Method (BEM) to simulate the whole process of underwater explosion detonated by column charge in this paper. Calculation results of various phases such as shock wave propagation, bubble pulsing and jet formation agree well with the experiment values. In this study, column charge detonation and bubble jet are successfully simulated via axisymmetric SPH method. The calculation results are still of highly precise at the symmetrical axis, verifying the feasibility of the axisymmetric SPH method established in this paper in the computation of three-dimensional underwater explosion, bubble jet and other physical problems. Meanwhile, axisymmetric SPH method and BEM are successfully combined in this paper to fully utilize their advantages, which is favorable in the solution of other hydrodynamic problems. © 2012 Elsevier Ltd.
Wu T.,Ship Research Institute |
Cheng K.,Brunel University
International Journal of Advanced Manufacturing Technology | Year: 2014
In an effort to prolong the tool life and improve the tooling performance in micro cutting, it is attractive and promising to apply diamond-like carbon (DLC) coatings on micro tools. Comprehensive understandings of micro cutting performance under various coating circumstances are essential for choosing optimum coating conditions so as for potentially improving cutting tool designs. In the study, the cutting characteristics of a DLC-coated tool has been extensively evaluated and compared with those of an uncoated tool under constant and various uncut chip thickness (UCT) using 2D plane-strain finite element method (FEM). The thermo-mechanical modelling approach has been validated at different UCT in micro milling. Besides, the influence of coating friction coefficient, coating thickness as well as UCT on the cutting forces and tool temperatures has been determined and analysed through design of experiment. It is found that appropriate UCT in micro cutting is of the greatest importance for achieving desirable coating performance of micro tools. © 2014 Springer-Verlag London.
A-man Z.,Harbin Engineering University |
A-man Z.,University College London |
Wen-shan Y.,Ship Research Institute |
Xiong-liang Y.,Harbin Engineering University
Applied Ocean Research | Year: 2012
Underwater contact explosion involves lots of complex issues such as high speed, strong compression, large deformation and density ratio, multi-phase flow, etc., which makes the numerical simulation extremely difficult. In this paper, a modified SPH approach based on volume approximation is applied and the entire process of shock wave propagation and structure destruction is successfully simulated. Results show that the modified method remains effective at interfaces with high density ratio, with no distortion of physical quantities. Therefore, the method has advantages of solving problems involving high speed, strong compression and high density ratio. In addition, shock wave propagation characteristics and a steel failure mode are found with simulation, which can be valuable reference for structural design of naval architecture and engineering of underwater explosion. © 2011 Elsevier Ltd.
Zhang A.M.,Harbin Engineering University |
Liu Y.L.,Ship Research Institute
Journal of Computational Physics | Year: 2015
Some new theoretical and numerical techniques are adopted in an improved 3D bubble dynamics model based on Boundary Element Method. Firstly, a numerical model under the incompressible potential assumption is established for 3D bubble dynamics, and the traditional technique for the vortex ring induced potential at the reference point in axisymmetric model is extended to arbitrary location in 3D model. Then, to homogenize the boundaries' mesh density, new Density Potential Method is put forward inspired by the Elastic Mesh Technique. It's combined together with the topology optimization based on edge swapping procedure to maintain a desirable mesh for the large deformation problem. Through the verification and the comparison by simulating a benchmark case, the improved model demonstrates good accuracy and stability. Particularly, more toroidal bubble evolution detailed features are captured which are in accordance with the axisymmetric model. Finally, bubble dynamics under different circumstances are simulated with the improved 3D numerical model presented in this paper, which shows that the improved model is also robust. © 2015 Elsevier Inc.
Du Z.H.,Ship Research Institute
Advanced Materials Research | Year: 2014
Compared with a great deal of traditional desulphurization crafts, the catalytic reduction of SO2 with CO to elemental sulfur is considered to be the best technology for the removal of SO2 from flue gas. Adding rare earth oxide CeO2 with variable valences to La2O3 formed a mixture of rare earth oxides. By means of dipping CeO2, La2O3 and their mixture, whose carriers are allγ-Al2O3, are used as the catalyst for the reduction of SO2 by CO. The activation process of this catalyst without O2 was investigated. The result shows that the rare earth oxide mixture composing of CeO2 and La2O3, as the catalyst for the reduction of SO2 by CO, can remove SO2 mostly without O2. © (2014) Trans Tech Publications, Switzerland.
Gangyi H.,Ship Research Institute |
Fei X.,Ship Research Institute |
Jun L.,Ship Research Institute
Composite Structures | Year: 2010
An approximation solution is introduced for the dynamic response of a two-layered cylindrical shell of circular cross-section subjected to an underwater explosive shock wave. The solution is obtained within the framework of the Flugge thin shell theory and the reflected-afterflow-virtual-source (RAVS) method is used to account for the fluid-structure interaction. Detailed numerical computations are carried out, in dimensionless form, for the cases of infinitely long two-layered cylindrical shells. Time histories of nondimensional radial velocity, mid-surface strain, 0th mode radial displacement and 1st mode radial velocity are presented in graphical form and the effects of elastic modulus, shell radius and thickness on the transient response characteristics of the shells are investigated. © 2009 Elsevier Ltd. All rights reserved.
Chen C.,Ship Research Institute
2014 17th IEEE International Conference on Intelligent Transportation Systems, ITSC 2014 | Year: 2014
As one important step of area-coordination in traffic management systems, the technology of network zoning is indispensable. On this topic, this paper introduces our work to reduce the burden of engineers on this problem. Firstly, inspired by the pros and cons of previous researches, we found three principles of zoning. Then, one model is proposed to measure the relationship between intersections for automatic identification of hierarchical characteristic of traffic network and adapt to the alternating busy-idle traffic environment. Under one certain traffic scene, a higher score of model means that two intersections have closer relationship and the related link has a higher coordination priority. Hence, using this model, we can rank the coordination priority of links in the network. Lastly, considering traffic network is one kind of directed spatial network, one network zoning method based on community detection is detailed to handel the characteristics of traffic network. We use a series of experiments on the traffic network in Tianhe area of Guangzhou to illustrate the effectiveness of this method and can be employed to handle large scale traffic networks. © 2014 IEEE.