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Chinese Physics B 2020年第4期29卷 179-189页

作者： S M Ngounou f B Pelap Unite de Recherche de Mecanique et de Modelisation des Systèmes Physiques(UR-2 MSP) Faculte des SciencesUniversite de DschangBP 69 DschangCameroun Unite de Recherche de Matiere Condensee d'Electronique et de Traitement du Signal(UR-MACETS) Faculte des SciencesUniversite de DschangBP 67 DschangCameroun

The dynamics of modulated waves in a nonlinear bi-inductance transmission line with dissipative elements are *** show the existence of two frequency modes and carry out intensive investigations on the low frequency *** to the multiple scales method,the behavior of these waves is investigated and the dissipative effects are *** appears that the dissipation coefficient increases with the carrier wave *** the continuous approximation,we derive that the propagation of these waves is governed by the complex Ginzburg-Landau equation instead of the Korteweg-de-Vries equation as previously *** studies of the dynamics of plane waves in the line reveal the existence of three additional regions in the dispersion curve where the modulational phenomenon is *** the low frequency mode,we demonstrate that the network allows the propagation of dark and bright *** findings are in perfect agreement with the analytical predictions.

关键词： dissipative bi-inductance network low frequency mode continuous approximation complex Ginzburg-Landau equation

Effect of electrical discharge in water on concentration of nitrate solution

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Chinese Physics B 2017年第2期26卷 305-312页

作者： f Sohbatzadeh H Bagheri R Safari Department of Atomic and Molecular Physics Faculty of Basic Sciences University of Mazandaran Babolsar lra

In this work, the effect of electrical discharge on nitrate concentration is considered in aqueous solution. The atmospheric pressure plasma was produced by a high-voltage power supply at 27 k Hz using pin-to-pin configuration. Air, argon,and argon/methane mixture were used to study the working gas effect. UV-VIS spectroscopy and ion chromatography were used to analyze the effect of the electrical discharge on nitrate concentration in deionized water. Optical emission spectroscopy（OES） was applied to diagnose active species inside and on the surface of the deionized water solution. The results of the present work showed that the atmospheric pressure electric discharge with air increases nitrate concentration while it remains constant using argon and argon/methane electrical discharges. It was also revealed that in the presence of air, the electrical discharge reduces p H, acidifying the solution and increasing solution conductivity due to production of extra nitrate ions. On the other hand, argon electrical discharge increases p H and conductivity due to production of OHion in water.

关键词： electric discharge nitrate solution optical spectroscopy

Photocurrent improvement of an ultra-thin silicon solar cell using the localized surface plasmonic effect of clustering nanoparticles

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Chinese Physics B 2020年第6期29卷 532-537页

作者： f Sobhani H Heidarzadeh H Bahador Department of Electrical and Computer Engineering University of Mohaghegh ArdabiliArdabilIran

The cluster-shaped plasmonic nanostructures are used to manage the incident light inside an ultra-thin silicon solar *** we simulate spherical,conical,pyramidal,and cylindrical nanoparticles in a form of a cluster at the rear side of a thin silicon cell,using the finite difference time domain(fDTD)*** calculating the optical absorption and hence the photocurrent,it is shown that the clustering of nanoparticles significantly improves *** photocurrent enhancement is the result of the plasmonic effects of clustering the *** comparison,first a cell with a single nanoparticle at the rear side is *** four smaller nanoparticles are put around it to make a *** photocurrents of 20.478 mA/cm2,23.186 mA/cm2,21.427 mA/cm2,and 21.243 mA/cm2 are obtained for the cells using clustering conical,spherical,pyramidal,cylindrical NPs at the backside,*** values are 13.987 mA/cm2,16.901 mA/cm2,16.507 mA/cm2,17.926 mA/cm2 for the cell with one conical,spherical,pyramidal,cylindrical NPs at the backside,***,clustering can significantly improve the ***,the distribution of the electric field and the generation rate for the proposed structures are calculated.

关键词： clustering nanoparticles plasmonic solar cell localized surface plasmon resonance photocurrent finite difference time domain(fDTD)method light management

Dynamics of high-frequency modulated waves in a nonlinear dissipative continuous bi-inductance network

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Chinese Physics B 2021年第6期30卷 193-205页

作者： S M Ngounou f B Pelap Unitéde Recherche de Mécanique et de Modélisation des Systèmes Physiques(UR-2 MSP) Facultédes SciencesUniversitéde DschangBP 69 DschangCameroun Unitéde Recherche de Matière Condensée d'Electronique et de Traitement du Signal(UR-MACETS) Facultédes SciencesUniversitéde DschangBP 67 DschangCameroun

This paper presents intensive investigation of dynamics of high frequency nonlinear modulated excitations in a damped bimodal lattice. The effects of the dissipation are considered through a linear dissipation coefficient whose evolution in terms of the carrier wave frequency is checked. There appears that the dissipation coefficient increases with the carrier wave frequency. In the linear limit and for high frequency waves, study of the asymptotic behavior of plane waves reveals the existence of two additional regions in the dispersion curve where the modulational phenomenon is observed compared to the lossless line. Based on the multiple scales method exploited in the continuum approximation using an appropriate decoupling ansatz for the voltage of the two different cells, it appears that the motion of modulated waves is described by a dissipative complex Ginzburg–Landau equation instead of a Korteweg–de Vries equation. We also show that this amplitude wave equation admits envelope and hole solitons in the high frequency mode. from basic sources, we design a programmable electronic generator of complex signals with desired characteristics, which delivers signals exploited as input waves for all our numerical simulations. These simulations are performed in the LTspice software that uses realistic components and give the results that corroborate perfectly our analytical predictions.

关键词： dissipative bi-inductance network high-frequency mode continuous approximation dissipative complex Ginzburg–Landau equation programmable electronic generator LT-Pspice observations

Building geospatial infrastructure

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Geo-Spatial Information Science 2020年第1期23卷 1-9页

作者： Jack Dangermond Michael f.Goodchild Esri RedlandsCAUSA Department of Geography University of CaliforniaSanta BarbaraCAUSA

Many visions for geospatial technology have been advanced over the past half *** researchers saw the handling of geospatial data as the major problem to be *** vision of geographic information systems arose as an early international *** visions included spatial data infrastructure,Digital Earth,and a nervous system for the *** accelerating advances in information technology,a new vision is needed that reflects today’s focus on open and multimodal access,sharing,engagement,the Web,Big Data,artificial intelligence,and data *** elaborate on the concept of geospatial infrastructure,and argue that it is essential if geospatial technology is to contribute to the solution of problems facing humanity.

关键词： Spatial data handling National Spatial Data Infrastructure Digital Earth Big Data citizen engagement

Review on supercapacitors:Technologies and performance evaluation

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Journal of Energy Chemistry 2021年第8期30卷 276-291,I0006页

作者： Jingyuan Zhao Andrew f.Burke Institute of Transportation Studies University of California-Davis95616 DavisUSA Computer Science and Technology Shenzhen Institutes of Advanced TechnologyChinese Academy of Sciences518118 ShenzhenChina

The development of electrochemical capacitors(***)have attracted a lot of attention in recent years because of the increasing demand for efficient,high-power energy *** capacitors(ECs)are particularly attractive for transportation and renewable energy generation applications,taking advantage of their superior power capability and outstanding cycle *** the past decade,various advanced electrode materials and cell design are being studied to improve the energy density of *** Li-ion capacitors and pseudo-capacitors that utilize fast surface redox reactions of metal oxide and doped polymers are the prime candidates being *** paper is concerned with the metrics being used to describe the performance of ECs and how the metrics are evaluated by testing devices and how the data from the testing are best *** is on relating testing of advanced ECs using materials more complex than activated carbons to testing electric double-layer capacitors(EDLCs)using carbon in both electrodes.A second focus of the paper is projecting the potential of the advanced materials and ionic liquid electrolytes for the development of complete EC cells having an energy density more than a factor of ten greater the energy density of the EDLC devices currently on the *** potential was evaluated by calculating the performance(energy and power)of a series of ECs that utilize the advanced materials that have been studied by electrochemists over the past 10-15 *** capacitance and resistance of the advanced ECs were calculated utilizing specific capacitance(f/g or f/cm^(3))and porosity data for the electrode materials and ionic conductivity of the *** was concluded that hybrid ECs can be developed with energy densities of at least 50 Wh/kg,70 Wh/L with efficient power greater than 3 k W/*** research on micro-porous carbons with specific capacitance of 200 f/g and greater is *** achieve th

关键词： Electrochemical capacitors Metrics Evaluation Cell design Applications

Integrated Low-cost Wastewater Treatment for Reuse in Irrigation

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Biomedical and Environmental Sciences 2000年第1期13卷 37-43页

作者： f.A.EL-GOHARY f.A.NASR R.A.WAHAAB Water Pollution Control Dept. National Research CentreTahreer St.DokkiCairoEgypt

for sustainable wastewater management in developing countries, the implementation of low\|cost, simple treatment systems should be encouraged. In this study, the performance of three treatment schemes was evaluated. The first step in all schemes was upflow anaerobic sludge blanket (UASB). The post treatment was either Algal Pond (AP). Lemna Pond (LP) or Rotating Biological Contactor (RBC). The results show that the performance of the UASB was satisfactory. Mean COD and BOD removal values were 78% and 85% respectively. The combination of UASB with an AP achieved significant improvement in the microbiological quality of the effluent. The geometric mean of fecal coliform in the effluent was 1.3×10 3 MPN/100ml. Residual COD was 143 mg O\-2/L. This relatively high value was due to the presence of algae in the AP effluent. The use of the LP as a post treatment achieved better quality effluent. As indicated by the physico\|chemical characteristics. However, fecal coliform removal was less by one log as compared to the AP effluent. When the RBC was used as a second stage. COD and BOD removal rates were 47% and 66% respectively. Also complete nitrification took place. fecal coliform density declined by 5 logs.

关键词： Water Supply Agriculture Algae Developing Countries Enterobacteriaceae Humans Sewage Waste Disposal, fluid Water Pollutants, Chemical

Predictions of decreased surface roughness after shot peening using controlled media dimensions

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Journal of Materials Science & Technology 2020年第23期58卷 120-129页

作者： Siavash Ghanbari David f.Bahr School of Materials Engineering Purdue UniversityWest LafayetteIN47907USA

Shot peening induces residual compressive stresses on metallic substrates, often used to decrease fatigue crack growth. The relationship between surface roughness and the magnitude of the stress can be affected by peening media size or the extent of peening. Generally, an ideal condition from shot peening would be a high compressive residual stress and a low surface roughness, but these tend to be inversely *** study proposes a method for decreasing roughness and increasing residual stress concurrently using a distribution of shot sizes in a single shot peening passage based on finite element modeling that has been calibrated using by experimental results. Numerical models predict mixed shot sizes will create a smoother surface than using monodispersed shot at 100 % coverage. The residual stress profile for mixed shot sizes showed a broad range of compressive residual stresses in comparison with the largest impact ball size. This newly proposed method can improve the surface quality and the extent of the compressive residual stresses in a single-shot peening passage.

关键词： Numerical analysis Shot peening Roughness

Effect of drainage on CO_2, CH_4, and N_2O fluxes from aquaculture ponds during winter in a subtropical estuary of China

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Journal of Environmental Sciences 2018年第3期30卷 72-82页

作者： Ping Yang Derrick Y.f Lai Jia f.Huang Chuan Tong School of Geographical Sciences Fujian Normal University Key Laboratory of Humid Sub-tropical Eco-geographical Process of Ministry of Education of China Fujian Normal University Department of Geography and Resource Management and Centre for Environmental Policy and Resource ManagementThe Chinese University of Hong Kong

Aquaculture ponds are dominant features of the landscape in the coastal zone of ***,aquaculture ponds are drained during the non-culture period in ***,the effects of such drainage on the production and flux of greenhouse gases（GHGs）from aquaculture ponds are largely *** the present study,field-based research was performed to compare the GHG fluxes between one drained pond（DP,with a water depth of 0.05 m）and one undrained pond（UDP,with a water depth of 1.16 m）during one winter in the Min River estuary of southeast *** the entire study period,the mean CO2flux in the DP was（0.75±0.12）mmol/（m^2·hr）,which was significantly higher than that in the UDP of（-0.49±0.09）mmol/（m^2·hr）（p0.01）.This indicates that drainage drastically transforms aquaculture ponds from a net sink to a net source of CO2in *** CH4and N2O emissions were significantly higher in the DP compared to those in the UDP（CH4=（0.66±0.31）vs.（0.07±0.06）mmol/（m^2·hr）and N2O=（19.54±2.08）vs.（0.01±0.04）μmol/（m^2·hr））（p〈0.01）,suggesting that drainage would also significantly enhance CH4and N2O *** in environmental variables（including sediment temperature,p H,salinity,redox status,and water depth）contributed significantly to the enhanced GHG emissions following pond ***,analysis of the sustained-flux global warming and cooling potentials indicated that the combined global warming potentials of the GHG fluxes were significantly higher in the DP than in the UDP（p〈0.01）,with values of739.18 and 26.46 mg CO2-eq/（m^2·hr）,*** findings suggested that drainage of aquaculture ponds can increase the emissions of potent GHGs from the coastal zone of China to the atmosphere during winter,further aggravating the problem of global warming.

关键词： Aquaculture pond Drainage management Greenhouse gas flux Global warming Min River estuary

Impact of discretization methods on the rough set-based classification of remotely sensed images

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International Journal of Digital Earth 2011年第4期4卷 330-346页

作者： Y.Ge f.Cao R.f.Duan State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences&Natural Resources ResearchChinese Academy of SciencesBeijing 100101P.R.China

In recent years,the rough set(RS)method has been in common use for remotesensing classification,which provides one of the techniques of information extraction for Digital *** discretization of remotely sensed data is an important data preprocessing approach in classical RS-based remote-sensing *** discretization methods can improve the adaptability of the classification rules and increase the accuracy of the remote-sensing *** assess the performance of discretization methods this article adopts three indicators,which are the compression capability indicator(CCI),consistency indicator(CI),and number of the cut points(NCP).An appropriate discretization method for the RS-based classification of a given remotely sensed image can be found by comparing the values of the three indicators and the classification accuracies of the discretized remotely sensed images obtained with the different discretization *** investigate the effectiveness of our method,this article applies three discretization methods of the Entropy/MDL,Naive,and SemiNaive to a TM image and three indicators for these discretization methods are then *** comparing the three indicators and the classification accuracies of the discretized remotely sensed images,it has been found that the SemiNaive method significantly reduces large quantities of data and also keeps satisfactory classification accuracy.

关键词： remote sensing classification rough set discretization image processing data mining