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Possible mechanism of the effect of convection over Asian-Australian “land bridge” on the East Asian summer monsoon onset

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Science China Earth Sciences 2006年第11期49卷 1223-1232页

作者： HE Jinhai1, WEN Min2, DING Yihui3.& ZHANG Renhe2 1. Jiangsu key Laboratory of Meteorological Disaster (KLME), Nanjing Institute of Meteorology, Nanjing University of Informa- tion Science and technology, Nanjing 210044, China 2. state key Laboratory of Severe Weather (LaSW), Chinese Academy of Meteorological Sciences, Beijing 100081, China 3. National Climate Center, Chinese Meteorological Administration, Beijing 100081, China 1. Jiangsu key Laboratory of Meteorological Disaster (KLME) Nanjing Institute of Meteorology Nanjing University of Information Science and Technology Nanjing 210044 China 2. state key Laboratory of Severe Weather (LaSW) Chinese Academy of Meteorological Sciences Beijing 100081 China 3. National Climate Center Chinese Meteorological Administration Beijing 100081 China

The Asian-Australian “land bridge” is an area with the most vigorous convection in Asian monsoon region in boreal spring, where the onset and march of convection are well associated with the onset of East Asian summer monsoon. The convection occurs over Indo-China Peninsula as early as mid-April, which exerts critical impact on the evolution of monsoon circulation. Before mid-April there are primarily sensible heatings to the atmosphere over Indo-China Peninsula and Indian Peninsula, so the apparent heating ratios over them decrease with height. However, after mid-April it changes into latent heating over Indo-China Peninsula due to the onset of convection, and the apparent heating ratio increases with height in mid- and lower troposphere. The vertical distribution of heating ratio and its differences between Indo-China Peninsula and Indian Peninsula are the key factors leading to the splitting of boreal subtropical high belt over the Bay of Bengal. Such mechanism is strongly supported by the fact that the evolution of the vertical heating ratio gradient above Indo-China Peninsula leads that of 850 hPa vorticity over the Bay of Bengal. Convections over Indo-China Peninsula and its surrounding areas further increase after the splitting. Since then, there is a positive feedback lying among the convective heating, the eastward retreat of the subtropical high and the march of monsoon, which is a possible mechanism of the advance of summer monsoon and convection from Indo-China Peninsula to South China Sea.

关键词： Asian-Australian 'land bridge', tropical convection, Indo-China Peninsula, the splitting of boreal subtropical high belt, East Asian summer monsoon onset.

Preparation,Structure and Dielectric Properties of Tungsten Bronze Ferroelectrics in SrO-Eu_2O_3.TiO_2-Nb_2O_5 System

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Journal of Wuhan University of technology(Materials Science) 2011年第2期26卷 312-315页

作者：胡长征 state Laboratory Breeding Base of Nonferrous Metals and Specific Materials Processing Guilin University of Technology key Laboratory of Nonferrous Materials and New Processing technology Ministry of EducationGuilin University of Technology state key Laboratory of Advanced technology for Materials Synthesis and Processing Wuhan University of Technology

Compounds Sr4Eu2Ti4Nb6O3. and Sr5EuTi3.b7O3. with filled tetragonal tungsten bronze structure were prepared,and the dielectric characteristics and ferroelectric transition were *** ceramics displayed weak frequency dependence in room temperature dielectric constant,which decreased from 125 to 118 for Sr4Eu2Ti4Nb6O3.,from 206 to 195 for Sr5EuTi3.b7O3. in the frequency range of 10 kHz to 1 *** present ceramics showed a diffuse ferroelectric phase *** frequency independent transition temperature （Tm） indicated the above compounds had no relaxor *** diffuseness （γ） was 1.45 and 1.64 for Sr4Eu2Ti4Nb6O3. and Sr5EuTi3.b7O3. *** weak ferroelectric of the present materials are indicated from the P-E hysteresis loops,and a small 2Pr of 0.596 μC/cm2 and 0.068 μC/cm2 were observed for Sr4Eu2Ti4Nb6O3. and Sr5EuTi3.b7O3. respectively.

关键词： tungsten bronze dielectric properties X-ray diffraction phase transition

Surface roughness and removal rate in magnetorheological finishing of a subsurface damage free surface

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Progress in Natural Science:Materials International 2005年第6期15卷 538-544页

作者： CHENG Haobo1*, WANG Yingwei2, FENG Zhijing1 and CHENG Kai3.1. state key Laboratory of Tribiology, Tsinghua University, Beijing 100084, China 2. Department of Material Sciences, Changchun University of Science and technology, Changchun 13.021, China 3. Faculty of Information and Engineering Systems, City Campus, Leeds LS1 3.E, UK) state key Laboratory of Tribiology Tsinghua University Beijing 100084 China Department of Material Sciences Changchun University of Science and Technology Changchun 130021 China Faculty of Information and Engineering Systems City Campus Leeds LS1 3HE UK

Based on computer-controlled optical surfacing, a new technique called magnetorheological finishing (MRF), is presented. The new technique combines the features of conventional loose abrasive machining with a wheel shaped polishing tool. The tool incorporates a host of features and has unprecedented fabricating versatility. The pre-polishing and fine polishing processes can be performed only by adjusting different parameters. The material removal function is studied theoretically and the results of simulation present a Gaussian distribution feature. Based on the established theoretical model, material removal rate experiments involving a parabolic mirror are designed and carried out to determine the effect of controllable parameters on size of the gap between the workpiece and the polishing wheel, rotating speed of the polishing wheel, concentration of volume fraction of non-magnetic particles and polishing time. Further experiments are carried out on the surface microstructure of the workpiece, the final surface roughness with an initial value of 10.98 nm reaches 1.22 nm root mean square (RMS) after 20 min of polishing. The subsurface damage experiment and the atomic force microscopy (AFM) measurement on the polished surface can also verify the feasibility of the MRF technique.

关键词： magnetorheological finishing surface roughness computer controlled optical surfacing subsurface damage removal function.

An adaptive version of ghost-cell immersed boundary method for incompressible flows with complex stationary and moving boundaries

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Science China(Physics,Mechanics & Astronomy) 2010年第5期53卷 923-932页

作者： WANG Liang1 & WU ChuiJie2,3.1 School of Science,PLA University of Science and technology,Nanjing 211101,China 2 state key Laboratory of Structural Analysis for Industrial Equipment,Dalian University of technology,Dalian 116024,China 3.School of Aeronautics and Astronautics,Dalian University of technology,Dalian 116024,China 1. School of Science PLA University of Science and Technology Nanjing 211101 China2. State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology Dalian 116024 China3. School of Aeronautics and Astronautics Dalian University of Technology Dalian 116024 China

An adaptive version of immersed boundary method for simulating flows with complex stationary and moving boundaries is *** method employs a ghost-cell methodology which allows for a sharp representation of the immersed *** simplify the implementation of the methodology,a volume-of-fluid method is introduced to identify the immersed *** addition,the domain is spatially discretized using a tree-based discretization which is relatively simple to implement a fully flexible adaptive refinement ***,the methodology is validated by comparing it with numerical and experimental results on three cases:(1) the flow passing a circular cylinder at Re=40 and Re=100,(2) a periodic oscillation of a circular cylinder in fluid at rest and(3. the self-propelled fish-like swimming at Re=6400.

关键词： adaptive mesh refinement ghost-cell immersed boundary method moving boundaries

A novel quantum information hiding protocol based on entanglement swapping of high-level Bell states

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Chinese Physics B 2015年第5期24卷 231-238页

作者：徐淑奖陈秀波王连海钮心忻杨义先 Shandong Provincial key Laboratory of Computer Networks Shandong Computer Science Center (National Supercomputer Center in Jinan) Information Security Center State Key Laboratory of Networking and Switching TechnologyBeijing University of Posts and Telecommunications state key Laboratory of Information Security Institute of Information Engineering Chinese Academy of Sciences

Using entanglement swapping of high-level Bell states, we first derive a covert layer between the secret message and the possible output results of the entanglement swapping between any two generalized Bell states, and then propose a novel high-efficiency quantum information hiding protocol based on the covert layer. In the proposed scheme, a covert channel can be built up under the cover of a high-level quantum secure direct communication （QSDC） channel for securely transmitting secret messages without consuming any auxiliary quantum state or any extra communication resource. It is shown that this protocol not only has a high embedding efficiency but also achieves a good imperceptibility as well as a high security.

关键词： quantum information hiding quantum covert'channel entanglement swapping high-level Bell states

The Research on Audio Information Hiding technology

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ZTE Communications 2007年第4期5卷 6-9页

作者： Yuan Kaiguo Yang Yu Yang Yixian (state key Laboratory of networking and {3. technology, Beijing University of Posts and Telecommunications, Beijing 100876, China)

Audio information hiding technology is an important branch of stenography. This article introduces the basic concepts, principles, characteristics and the typical models of the audio information hiding. It then classifies the audio information hiding methods, according to the domain used by them including time, frequency, Discrete Cosine Transform (DCT), Discrete Wavelet Transform (DWT) and the compressed., and discusses several mainstream algorithms in various domains. It finally points out that the audio information hiding technology cannot solve the problem of re-record attacks, but it also brings forward the possible solutions to this problem.

关键词： The Research on Audio Information Hiding technology LSB DCT IEEE

Fractal Analysis of Gas Diffusion Layer in PEM Fuel Cells

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Journal of Wuhan University of technology(Materials Science) 2006年第1期21卷 22-25页

作者：石英肖金生 state key Laboratory of Advanced technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070ChinaSchool of Automation Wuhan University of Technology Wuhan 430070 China state key Laboratory of Advanced technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070ChinaSchool of Automotive EngineeringWuhan University of Technology Wuhan 430070China

The aim of this study is to show how fractal analysis can be effectively used to characterize the texture of porous solids. The materials under study were carbon papers, the backing material of the gas diffusion layer （GDL） in Proton Exchange Membrane Fuel Cell （PEMFC）. The fractal dimensions were calculated by analyzing data from mercury porosimetry. The polytotrafluoroethylene （PTFE） treated carbon paper shows a significantly high fractal dimension value than pare sample, and the high fractal dimension signifies that the physical complexity of the pore surface is enhanced. The fractal dimension can be used as a valid parameter to monitor the textural evolution of the samples as the treatment progresses, as this behaves in a similar way to other textural parameters. The use of fractal analysis in conjunction with the results of classical characterization methods leads to a better understanding of textural modificatious in the processing of materials.

关键词： PEMFC gas diffusion layer fractal dimension mewury porosimetry

A modified method for simulating non-stationary multi-point earthquake ground motion

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Earthquake Engineering and Engineering Vibration 2010年第2期9卷 201-211页

作者： Li Minggao,Li Xin and Zhou Jing state key Laboratory of Coastal and Offshore Engineering,Dalian University of technology,Dalian 116024,China state key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116024 China

A spectral-representation-based algorithm is proposed to simulate non-stationary and stochastic processes with evolutionary power,according to a prescribed non-stationary cross-spectral density matrix. Non-stationary multi-point seismic ground motions at different locations on the ground surface are generated for use in engineering applications. First,a modified iterative procedure is used to generate uniformly modulated non-stationary ground motion time histories which are compatible with the prescribed power spectrum. Then,ground motion time histories are modeled as a non-stationary stochastic process with amplitude and frequency modulation. The characteristic frequency and damping ratio of the Clough-Penzien acceleration spectrum are considered as a function of time in order to study the frequency time variation. Finally,two numerical examples are presented to validate the efficiency of the proposed method,and the results show that this method can be effectively applied to the dynamic seismic analysis of long and large scale structures.

关键词： multi-support excitation spatial correlation power spectrum-compatibility non-stationary ground motion simulation

Removal of elemental mercury by iodine-modified rice husk ash sorbents

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Journal of Environmental Sciences 2010年第10期22卷 1629-1636页

作者： Pengfei Zhao,Xin Guoff,Chuguang Zheng state key Laboratory of Coal Combustion,Huazhong University of Science and technology,Wuhan 43.074,China [a] state key Laboratory of Coal Combustion Huazhong University of Science technology Wuhan 430074 China

Iodine-modified calcium-based rice husk ash sorbents （I2/CaO/RHA） were synthesized and characterized by X-ray diffraction, X-ray fluorescence, and N2 isotherm adsorption/desorption. Adsorption experiments of vapor-phase elemental mercury （Hg^0） were performed in a laboratory-scale fixed-bed reactor. I2/CaO/RHA performances on Hg^0 adsorption were compared with those of modified Cabased fly ash sorbents （I2/CaO/FA） and modified fly ash sorbents （I2/FA）. Effects of oxidant loading, supports, pore size distribution, iodine impregnation modes, and temperature were investigated as well to understand the mechanism in capturing Hg^0. The modified sorbents exhibited reasonable efficiency for Hg^0 removal under simulated flue gas. The surface area, pore size distribution, and iodine impregnation modes of the sorbents did not produce a strong effect on Hg^0 capture efficiency, while fair correlation was observed between Hg^0 uptake capacity and iodine concentration. Therefore, the content of 12 impregnated on the sorbents was identified as the most important factor influencing the capacity of these sorbents for Hg^0 uptake. Increasing temperature in the range of 80-140℃ caused a rise in Hg^0 removal. A reaction mechanism that may explain the experimental results was presumed based on the characterizations and adsorption study.

关键词： mercury sorbents fly ash rice husk ash iodine impregnation