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1
Content available remote Dispersion calculation method based on S-transform and coordinate rotation for Love channel waves with two components
Feng L., Zhang Y.
Acta Geophysica
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2017
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Vol. 65, no. 4
757--764
EN
Dispersion analysis is an important part of in-seam seismic data processing, and the calculation accuracy of the dispersion curve directly influences pickup errors of channel wave travel time. To extract an accurate channel wave dispersion curve from in-seam seismic two-component signals, we proposed a time–frequency analysis method based on single-trace signal processing; in addition, we formulated a dispersion calculation equation, based on S-transform, with a freely adjusted filter window width. To unify the azimuth of seismic wave propagation received by a two-component geophone, the original in-seam seismic data undergoes coordinate rotation. The rotation angle can be calculated based on P-wave characteristics, with high energy in the wave propagation direction and weak energy in the vertical direction. With this angle acquisition, a two-component signal can be converted to horizontal and vertical directions. Because Love channel waves have a particle vibration track perpendicular to the wave propagation direction, the signal in the horizontal and vertical directions is mainly Love channel waves. More accurate dispersion characters of Love channel waves can be extracted after the coordinate rotation of two-component signals.
2
Content available Adsorption mechanism of sodium oleate on titanium dioxide coated sensor surface using quartz crystal microbalance with dissipation
Fan G., Liu J., Cao Y., Feng L., Xu H.
Physicochemical Problems of Mineral Processing
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2016
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Vol. 52, iss. 2
597--608
EN
Quartz Crystal Microbalance with Dissipation (QCM-D) was firstly applied to investigate the adsorption mechanism of sodium oleate on TiO2 coated sensor surface. The effects of pH value, sodium oleate concentration, and temperature on TiO2 coated sensor surface were evaluated systematically using the QCM-D technique. Zeta potential, surface tension, adsorption isotherms, and adsorption thermodynamics were employed to characterize the adsorption process. The results showed the advantages of QCM-D on the investigation of the adsorption process. Additionally, the electrostatic equilibrium adsorption data was well matched to the Langmuir isotherm. Based on the thermodynamic analysis, adsorption was a spontaneous and endothermic physisorption process.
3
Content available Endogenous timing in a vertically differentiated mixed duopoly with Cournot competition
Feng L., Gu M.
Archives of Control Sciences
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2016
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Vol. 26, no. 2
161--175
EN
This paper compares the equilibrium outcomes under simultaneous and sequential output setting in a mixed duopoly in a vertically differentiated market. When the timing of the output game is determined endogenously, it is shown that simultaneous play in the quality stage with the public firm acting as the high-quality producer and simultaneous play in the second period in the output stage turn out to be the unique subgame perfect Nash equilibrium, which contrasts with the endogenous timing in a purely private duopoly.
4
Content available remote Output Characteristics and MPPT Research for PV Array dunder Partially Shaded Conditions
Jia L., Chen K., Li G., Feng L., Jiang X.
Przegląd Elektrotechniczny
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2013
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R. 89, nr 1b
279--283
EN
MPPT(maximum power point tracking) has been one of the hot issues in PV power system all the time. At present, most of MPPT methods are very efficient only under uniform irradiance. However, the output power-voltage curve presents multi-peak characteristics under PSCs (partially shaded conditions), which is one challenge of the MPPT technology. In this paper, the segment characteristics of PV array, which is made by PV modules in series-parallel (SP) connection, was analyzed in details under PSCs. And then a GMPPT (global maximum power point tracking) algorithm was proposed based on the segment model. The MPPT controller using this algorithm can rapidly locate the segment where the GMPP(Global Maximum Power Point) is in and then converges the working point to GMPP using an improved InC (Incremental Conductance) method. A Matlab/SIMULINK model verifies that the proposed algorithm is efficient under both uniform irradiance and PSCs.
PL
System śledzenia warunków maksymalnej mocy MPPT jest powszechnie stosowany w systemach fotowoltaicznych. Systemy te w większości działają w warunkach jednorodnego nasłonecznienia. W artykule zaproponowano system śledzenia mocy w warunkach częściowego nasłonecznienia.
5
Content available Peripheral challenge by Small and Medium Sized Ports (SMPs) in Multi-Port Gateway Regions: the case study of northeast of China
Feng L., Notteboom T.
Polish Maritime Research
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2013
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S 1
55--66
EN
This paper focuses on the role of small and medium-sized ports (SMPs) in enhancing the competitiveness and logistics performance of multi-port gateway regions and associated inland logistics systems. The concepts developed will be applied to the ports in the northeast of China, a multi-port gateway region around the Bohai Sea Economic Rim (BER). Port competition is analyzed by multi-variable methodology and generalized common characteristics of SMPs compared to gateway ports, and the similarities of SMPs and SMEs are also compared. Later in this paper, we analyze the role of a SMP in such region in different variables: (a) cargo volume and market share; (b) international connectivity; (c) relative cluster position; (d) port city and hinterland connection; and (e) logistics and distribution function. The five-dimension analysis combined with in-depth cases study of typical Yingkou port describes a profile of SMPs in the BER and provides future study possibility for more SMPs cases worldwide.
6
Content available remote Structural, electrical and optical properties of AZO/SiO2/p-Si SIS heterojunction prepared by magnetron sputtering
Bo H., Ma Z. Q., Jing X., Lei Z., Sheng Z. N., Feng L., Cheng S., Ling S., Jie M. X., Yue Z. C., Shan Y. Z., Ting Y. Y.
Optica Applicata
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2010
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Vol. 40, nr 1
15--24
EN
ZnO thin films doped with aluminum (AZO) were deposited on silicon dioxide covered type texturized Si substrates by radio frequency magnetron sputtering, to fabricate AZO/SiO2/p-Si heterojunction, as an absorber for ultraviolet cell. The microstructure, optical and electrical properties of the Al-doped ZnO films were characterized by XRD, SEM, UV-VIS spectrophotometer, current-voltage measurement, and four point probe technique, respectively. The results show that AZO films are of good quality. The electrical junction properties were investigated by I-V measurement, which reveals that the heterojunction shows rectifying behavior under a dark condition. The ideality factor and the saturation current of this diode are 24.42 and 8.92×10-5 A, respectively. And the values of IF/IR (IF and IR stand for forward and reverse current, respectively) at 10 V are found to be as high as 38. It shows fairly good rectifying behavior indicating formation of a diode between AZO and p-Si.
7
Content available remote Fabrication and photoelectrical properties of a novel violet and blue enhanced SINP silicon photovoltaic device
Bo H., Ma Z. Q., Jing X., Lei Z., Sheng Z. N., Feng L., Feng L., Cheng S., Ling S., Jie M. X., Jie M. X., Yue Z. C., Shan Y. Z.., Ting Y. Y.
Optica Applicata
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2009
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Vol. 39, nr 3
547-560
EN
A novel ITO/SiO2/np-silicon violet and blue enhanced photovoltaic device with SINP structure has been fabricated by thermal diffusion of phosphorus. The shallow junction was formed to enhance the spectral responsivity within the wavelength range of 400-600 nm. An ultrathin silicon dioxide was thermally grown at low temperature and RF sputtering of ITO antireflection coating to reduce the reflected light and enhance the sensitivity. The crystalline structure, optical and electric properties of ITO film were determined by an XRD, UV-VIS spectrophotometer, a four point probe and the Hall effect measurement, respectively. The results show that ITO film has high quality. The current-voltage (I-V) characteristics, spectral response and responsivity of the photovoltaic device with high quantum efficiency of violet SINP and deep junction SINP structure were calculated and analyzed in detail.
8
Content available remote Improved RoI-based remote sensing image compression
Feng L., Jiaxiong P.
Image Processing & Communications
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2003
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Vol. 9, no 1-2
3-15
EN
The paper proposes an improved version of Rol - based coding for compressing remote sensing images. A fully automatic background - clustering algorithm is used based on some features which have fully considered the characteristics of region of interest - based image compression scheme. The new model has three advantages: allowing near-lossless Rol segmentation; reducing the ambiguity of reconstructed Rol edge; enhancing intelligibility for Rol in reconstructed image. The paper also introduce Wold feature. The feature can capture random texture as well as structural texture, and hence is better than other purely stochastic texture features. Some results on remote sensing images arę presented.
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