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Two-way coupling model for shock-induced laminar boundary-layer flows of a dusty gas

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Acta Mechanica Sinica 2005年第6期21卷 557-563页

作者： Boyi Wang yi xiong A.N. Osiptsov LNM Institute of Mechanics Chinese Academy of SciencesBeijing 100080 China Institute of Mechanics Moscow State University119899 Moscow Russia

The present paper describes a numerical two-way coupling model for shock-induced laminar boundary-layer flows of a dust-laden gas and studies the transverse migration of fine particles under the action of Saffman lift force. The governing equations are formulated in the dilute twophase continuum framework with consideration of the finiteness of the particle Reynolds and Knudsen numbers. The full Lagrangian method is explored for calculating the dispersedphase flow fields （including the number density of particles） in the regions of intersecting particle trajectories. The computation results show a significant reaction of the particles on the two-phase boundary-layer structure when the mass loading ratio of particles takes finite values.

关键词： Shock wave Dusty gas Two-phase boundary layer Two-way coupling Numerical modeling

Exploratory study of logistics service quality scale based on online shopping malls

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第6期8卷 926-931页

作者： FENG yi-xiong ZHENG Bing TAN Jian-rong State Key Lab. of CAD ＆ CG Zhejiang University Hangzhou 310027 China College of Economics ＆ Management Dalian University Dalian 116622 China

Online shopping has already become the new mode that a lot of customers try to adopt. At the same time, the online shopping could not be successfully completed without logistics service. Logistics service quality (LSQ) has significant impact on revenue and profitability. This paper presents the issue from the perspective of the customer, and explores the initial factors of LSQ based on the online shopping through in-depth interview and the Delphi method. The survey uses a standard 7-point Likert-type scale to measure the LSQ. Empirical research results are shown in detail to confirm seven LSQ dimensions with Chinese characteristics, including timeliness quality, personal contact quality, order quality, order discrepancy handling, order condition and convenience. Statistical analyses of the investigation were conducted to test the reliability and validity of the LSQ evaluation model.

关键词： Online shopping Logistics service Logistics service quality (LSQ) Dimensions of LSQ

Joining of C_f/SiBCN composite with two Ni-based brazing fillers and interfacial reactions

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Journal of Materials Science & Technology 2017年第5期33卷 487-491页

作者： Wenwen Li Bo Chen yi xiong Huaping xiong Yaoyong Cheng Wenjiang Zou Welding and Plastic Forming Division Beijing Institute of Aeronautical Materials School of Materials University of Manchester

G/SiBCN ceramic composite was joined using Ni-19Cr-10Si （BNi5） and Ni-33Cr-24Pd-3.5Si-0.5B filler alloys at 1170 ℃ for 10 min. Two kinds of Ni-based filler alloys exhibited good wettability on the CdSiBCN com- posite, with a contact angle of 13° and 4°, respectively, The microstructures of the brazed joints were investigated by electron-probe microanalysis （EPMA）, and three-point bend test was conducted for the joints at room temperature. When being brazed with BNi5 filler alloy, no evident reaction layer was ob- served at the surface of the joined composite, and the joint microstructure was characterized by Ni2Si matrix with scatteringly distributing mixture compounds of Cr23C6, Ni2Si and CrB. While Ni-Cr-Pd（Si,B） brazing alloy was used, a Cr23C6 reaction layer with a thickness of 11 μm was formed at the surface of the base composite. In the central part of the brazed joint, the phases were composed of Ni（Cr, Si） solid solution and complex compounds including Pd2Si, （Ni,Pd）2Si and Ni-B. The strength of Cf/SiBCN joint brazed with BNi5 filler alloy was 62.9 MPa at room temperature, whereas that with Ni-Cr-Pd（Si,B） filler alloy was at the same level.

关键词： Cf/SiBCN composite Brazing Microstructure Joint strength Interracial reaction

A comparative study of fuzzy weights of evidence and random forests for mapping mineral prospectivity for skarn-type Fe deposits in the southwestern Fujian metallogenic belt, China

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Science China Earth Sciences 2016年第3期59卷 556-572页

作者： ZHANG Zhen Jie ZUO Ren Guang xiong yi Hui School of Earth Sciences and Resources China University of Geosciences State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences

Recent studies have pointed out that the widespread iron deposits in southwestern Fujian metallogenic belt(SFMB)(China) are skarn-type deposits associated with the Yanshanian granites. There is still excellent potential for mineral exploration because large areas in this belt are covered by forest. A new predictive model for mapping skarn-type Fe deposit prospectivity in this belt was developed and focused on in this study, using five criteria as evidence:(1) the contact zones of Yanshanian granites(GRANITE);(2) the contact zones within the late Paleozoic marine sedimentary rocks and the carbonate formations(FORMATION);(3) the NE-NNE-trending faults(FAULT);(4) the zones of skarn alterations(SKARN); and(5) the aeromagnetic anomaly(AEROMAGNETIC). The fuzzy weights of evidence(FWof E) method, developed from the classical weights of evidence(Wof E) and based on fuzzy sets and fuzzy probabilities, could provide smaller variances and more accurate posterior probabilities and could effectively minimize the uncertainty caused by omitted or wrongly assigned data and be more flexible than the Wof E. It is an efficient and widely used method for mineral potential mapping. Random forests(RF) is a new and useful method for data-driven predictive mapping of mineral prospectivity method, and needs further scrutiny. Both prospectivity results respectively using the FWof E and RF methods reveal that the prediction model for the skarn-type Fe deposits in the SFMB is successful and efficient. Both methods suggested that the GRANITE and FORMATION are the most valuable evidence maps, followed by SKARN, AEROMAGNETIC, and FAULT. This is coincident with the skarn-type Fe deposit mineral model in the SFMB. The unstable performance experienced when FORMATION was omitted might indicate that the highest uncertainty and risk in follow-up exploration is related to the sequences. In addition, the performance of the RF method for the skarn-type Fe deposits prospectivity in the SFMB is better than

关键词： Mineral prospectivity mapping Fuzzy weights of evidence Random forest Skarn-type Fe Makeng deposit

Bio-synthesized palladium nanoparticles using alginate for catalytic degradation of azo-dyes

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Chinese Journal of Chemical Engineering 2020年第5期28卷 1334-1343页

作者： yi xiong Liping Huang Sakil Mahmud Feng Yang Huihong Liu College of Chemistry and Chemical Engineering Hubei Key Laboratory of Biomass Fibers and Eco-dyeing&FinishingWuhan Textile UniversityWuhan 430200China Ningbo Institute of Materials Technology and Engineering Chinese Academy of SciencesNingbo 315201China University of Chinese Academy of Sciences Beijing 100049China

Palladium nanoparticles(PdNPs)were synthesized in a green way using sodium alginate functioning as both reductant and *** formation of as-synthesized Pd NPs was supervised by Ultraviolet–visible(UV–Vis)spectroscopy and confirmed by the surface plasmon resonance(SPR)*** effect of several synthesis factors such as precursor ratio,solution p H,reaction time,and temperature were investigated by the factorial design of experiments in order to optimize the experimental *** optimal synthesis parameters were achieved by heating 1.0 ml of 1.0%sodium alginate(SA),3.0 ml of 10-2 mol·L-1 H2PdCl4 at 80°C for a period of 30 min in a neutral reaction medium(pH=6).High-resolution transmission electron microscope(HRTEM),energy dispersive X-ray(EDX)spectroscopy,selected area electron diffraction(SAED)pattern,X-ray powder diffraction(XRD),and dynamic light scattering(DLS)were used to confirm the uniform spherical shapes and high crystallinity of Pd NPs with average particle size of(2.12±1.42)*** SEM images show the distribution of Pd NPs presented among the *** spectra indicate that SA is a good capping agent to stabilize Pd NPs for a long *** catalytic degradation of model azo-dyes such as mono-azo(Cibacron Yellow FN–2R)and di-azo(Cibacron Deep Red S–B)were confirmed the catalytic activity of Pd *** Pd NPs can accelerate the degradation rate by more than 80 and 10 times respectively as confirmed by kinetics constant(k)values.

关键词： Palladium nanoparticles sodium alginate Green synthesis Azo dyes Catalysis

Silica optical fiber integrated with two-dimensional materials:towards opto-electro-mechanical technology

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Light(Science & Applications) 2021年第5期10卷 767-784页

作者： Jin-hui Chen yi-feng xiong Fei Xu Yan-qing Lu Institute of Electromagnetics and Acoustics Xiamen UniversityXiamen 361005China College of Engineering and Applied Sciences National Laboratory of Solid State Microstructures and Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China

In recent years,the integration of graphene and related two-dimensional(2D)materials in optical fbers have stimulated signifcant advances in ll-fber photonics and *** conventional passive silia fiber devices with 2D materials are empowered for enhancing light-matter interactions and are applied for manipulating light beams in respect of their polarization,phase,intensity and frequency,and even realizing the active photo-electric conversion and electro-optic modulation,which paves a new route to the integrated multifunctional ll-fber optoelectronic *** article reviews the fast-progress field of hybrid 2D-materials-optical fiber for the opto-electro-mechanical *** challenges and opportunities in this field for future development are discussed.

关键词： fiber optical polarization

Video coding using geometry based block partitioning and reordering discrete cosine transform

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Journal of Zhejiang University-Science C(Computers and Electronics) 2012年第1期13卷 71-82页

作者： yi-xiong ZHANG Jiang-hong SHI Wei-dong WANG Department of Communication Engineering Xiamen University Xiamen 361005 China Department of information Science and Electronic Engineering Zhejiang University Hangzhou 310027 China

Geometry based block partitioning （GBP） has been shown to achieve better performance than the tree structure based block partitioning （TSBP） of H.264. However, the residual blocks of GBP mode after motion compensation still present some non-vertical/non-horizontal orientations, and the conventional discrete cosine transform （DCT） may generate many high-frequency coefficients. To solve this problem, in this paper we propose a video coding approach by using GBP and reordering DCT （RDCT） techniques. In the proposed approach, GBP is first applied to partition the macroblocks. Then, before performing DCT, a reordering operation is used to adjust the pixel positions of the residual macroblocks based on the partition information. In this way, the partition information of GBP can be used to represent the reordering information of RDCT, and the bitrate can be reduced. Experimental results show that, compared to H.264/AVC, the proposed method achieves on average 6.38% and 5.69% bitrate reductions at low and high bitrates, respectively.

关键词： Geometry based block partitioning Reordering DCT Motion compensation Video coding

Frame rate up-conversion using multiresolution critical point filters with occlusion refinement

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第12期9卷 1621-1630页

作者： yi-xiong ZHANG Wei-dong WANG Peng LIU Qing-dong YAO Department of Information Science and Electronic Engineering Zhejiang University Hangzhou 310027 China

In this paper, multiresolution critical-point filters （CPFs） are employed to image matching for frame rate up-conversion （FRUC）. By CPF matching, the dense motion field can be obtained for representing object motions accurately. However, the elastic motion model does not hold in the areas of occlusion, thus resulting in blur artifacts in the interpolated frame. To tackle this problem, we propose a new FRUC scheme using an occlusion refined CPF matching interpolation （ORCMI）. In the proposed approach, the occlusion refinement is based on a bidirectional CPF mapping. And the intermediate frames are generated by the bidirectional interpolation for non-occlusion pixels combined with unidirectional projection for the occlusion pixels. Ex- perimental results show that ORCMI improves the visual quality of the interpolated frames, especially at the occlusion regions. Compared to the block matching based FRUC algorithm, ORCM1 can achieve 1-2 dB PSNR gain for standard video sequences.

关键词： Frame rate up-conversion Multiresolution critical-point filters Occlusion refinement

Nonlinear Trajectory SAR Imaging Algorithms:Overview and Experimental Comparison

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Journal of Beijing Institute of Technology 2023年第6期32卷 653-669页

作者： yi xiong Buge Liang Ning Wang Jianlai Chen School of Automation Central South UniversityChangsha 410083China Laboratory of Pinghu Shenzhen 518100China

The nonlinear characteristics of the motion trajectory of the synthetic aperture radar(SAR)flight platform can lead to severe two-dimensional space-variance characteristics of the signal,greatly affecting the imaging quality,and are currently considered as one of the difficulties in the field of SAR *** paper first discusses the nonlinear trajectory SAR model and its space-variance characteristics and then discusses algorithms such as scaling-based algorithms,interpolation-based algorithms,time-domain algorithms,and hybrid *** relative merits and applicability of each algorithm are ***,computer simulation and actual data validation are conducted.

关键词： two-dimensional space-variance nonlinear synthetic aperture radar(NL-SAR) slant range model