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Viscous Modified Chaplygin Gas in Classical and Loop Quantum Cosmology

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Chinese Physics Letters 2017年第6期34卷 139-143页

作者： D. Aberkane N. Mebarki S. Benchikh laboratoire de Physique Mathematique et Subatomique Mentouri University Constantine 25000 Algeria

We investigate the cosmological model of viscous modified Chaplygin gas （VMCG） in classical and loop quantum cosmology （LQC）. Firstly, we constrain its equation of state parameters in the framework of standard cosmology from Union 2.1 SNe Ia data. Then, we probe the dynamical stability of this model in a universe filled with VMCG and baryonic fluid in LQC background. It is found that the model is very suitable with （χ2/d.o.f = 0.974） and gives a good prediction of the current values of the deceleration parameter q0 =∈ （-0.60, -0.57） and the effective state parameter ωeff∈ （-0.76, -0.74） that is consistent with the recent observational data. The model can also predict the time crossing when （ρDE ≈ Pmatter） at z = 0.75 and can solve the coincidence problem. In LQC background, the Big Bang singularity found in classical cosmology ceases to exist and is replaced by a bounce when the Hubble parameter vanishes at ρtot≈ρc.

关键词： Viscous Modified Chaplygin Gas in Classical and Loop Quantum Cosmology

Unified treatment of the bound states of the Schioberg and the Eckart potentials using Feynman path integral approach

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Chinese Physics B 2015年第2期24卷 39-45页

作者： A.Diaf laboratoire de l'nergie et des Systemes Intelligents Université de Khemis Miliana

We obtain analytical expressions for the energy eigenvalues of both the Schioberg and Eckart potentials using an approximation of the centrifugal term. In order to determine the l-states solutions, we use the Feynman path integral approach to quantum mechanics. We show that by performing nonlinear space-time transformations in the radial path integral, we can derive a transformation formula that relates the original path integral to the Green function of a new quantum solvable system. The explicit expression of bound state energy is obtained and the associated eigenfunctions are given in terms of hypergeometric functions. We show that the Eckart potential can be derived from the Schioberg potential. The obtained results are compared to those produced by other methods and are found to be consistent.

关键词： path integrals l-states Schioberg potential Eckart potential

Performance of PI controller for control of active and reactive power in DFIG operating in a grid-connected variable speed wind energy conversion system

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Frontiers in Energy 2014年第3期8卷 371-378页

作者： Azzouz TAMAARAT Abdelhamid BENAKCHA laboratoire LGEB Biskra University Biskra City 07000 Algeria

Due to several factors, wind energy becomes an essential type of electricity generation. The share of this type of energy in the network is becoming increasingly important. The objective of this work is to present the modeling and control strategy of a grid connected wind power generation scheme using a doubly fed induction generator （DFIG） driven by the rotor. This paper is to present the complete modeling and simulation of a wind turbine driven DFIG in the second mode of operating （the wind turbine pitch control is deactivated）. It will introduce the vector control, which makes it possible to control independently the active and reactive power exchanged between the stator of the generator and the grid, based on vector control concept （with stator flux or voltage orientation） with classical PI controllers. Various simula- tion tests are conducted to observe the system behavior and evaluate the performance of the control for some optimization criteria （energy efficiency and the robustness of the control）. It is also interesting to play on the quality of electric power by controlling the reactive power exchanged with the grid, which will facilitate making a local correction of power factor.

关键词： wind power doubly fed induction generator(DFIG) vector control active power reactive power,maximum power point tracking (MPPT)

Anaerobic Removal of Trace Organic Contaminants in Sewage Sludge: 15 Years of Experience

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Pedosphere 2012年第4期22卷 508-517页

作者： M. BARRET L. DELGADILLO-MIRQUEZ E. TRABLY N. DELGENES F. BRAUN G. CEA-BARCIA J. P. STEYER D. PATUREAU INRA UR0050 Laboratoire de Biotechnologie de l'Environnement

Trace organic contaminants (TOCs) correspond to a broad range of molecules generated either directly or indirectly by human activity. Even though TOCs are found at low concentrations in the environment, they often accumulate by biomagnification and bioaccumulation into biological organisms and cause irreversible damages in biological systems through direct or indirect toxic effects such as endocrine disruption and tumour initiation. This manuscript presents the main findings of over fifteen years of research focusing on biological removal of various TOCs found in sewage sludge from urban treatment plants. A special focus of the research was made on microbial processes in complex anaerobic ecosystems. Four families of compounds mostly retrieved in urban plants were studied: the polycyclic aromatic hydrocarbons (PAHs), the polychlorobiphenyls (PCBs), the phthalic acid esters (PAEs), and the nonylphenol ethoxylates (NPEs). It was observed that the microbial capability for removing low amounts of TOCs required a long adaptation time and was often limited by the bioavailability of these compounds. In fact, the overall biodegradation resulted from the numerous interactions existing between the matrix (organic matter) and the microbial ecosystems according to the physico-chemical sorption properties of these compounds. Mechanistic aspects were also tackled in depth and specific models were developed for better understanding the network of interactions between TOCs, microorganisms, and organic matter. These findings could be extrapolated to other ecosystems such as soils and sediments. Finally, it was shown that microbial cometabolism was essential for TOC removal, and the concept of bioavailability was not only dependent on the nature, the level, and the sorption properties of TOCs but was also strongly dependent on the nature and the concentration of the sludge organic matter. Specific parameters were proposed for better evaluating the fate of TOCs in microbial anaerobic

关键词： anaerobic digestion bioavailability biodegradation microbial cometabolism organic matter

Surface morphology and electrochemical characterization of electrodeposited Ni-Mo nanocomposites as cathodes for hydrogen evolution

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Chinese Physics B 2015年第10期24卷 559-563页

作者： Elhachmi Guettaf Temam Hachemi Ben Temam Said Benramache laboratoire de Physique des Couches Minces et Applications Université de Biskra

In this work, we study the influences of current density on surface morphology and electrochemical characterization of electrodeposited Ni-Mo. The Ni-Mo composite coatings are deposited on pretreated copper substrates by electrolytic deposition. The Ni-Mo solution is taken from nickel sulfate fluid and ammonium heptamolybdate with 10 g/l. The Ni-Mo composite coatings are deposited at a temperature of 303 K with an applied current density of j dep= 10 A/dm2-30 A/*** find that the corrosion resistance is improved by incorporating Mo particles into Ni matrix in 0.6-M Na Cl solution. From the potentiodynamic polarization curve of electrodeposited Ni-Mo it is confirmed that the corrosion resistance decreases with increasing applied current density. The x-ray diffraction（XRD） analyses of Ni-Mo coatings indicate three phases of Mo Ni4, Mo1.24Ni0.76, and Ni3 Mo phases crystallites of nickel and molybdenum. The scanning electronic microscopy（SEM） tests indicate that Ni-Mo coatings present cracks and pores.

关键词： Ni-Mo electrolytic deposition corrosion resistance potentiodynamic polarization plating current density

Electrical model parameters identification of radiofrequency discharge in argon through 1D3V/PIC-MC model

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Plasma Science and Technology 2018年第9期20卷 106-113页

作者： Mohamed MOSTAFAOUI Djilali BENYOUCEF laboratoire Génie Electrique et Energies Renouvelables Université Hassiba Benbouali de Chlef

This work represents a contribution to the modeling of a radiofrequency（RF） discharge in argon at low pressure（from 25 to 200 mTorr）.It is started by the validation of the collision cross sections used in the particle model through a comparison between the transport coefficients calculated by these data and the measurements of the transport coefficients already exist in the literature,the particle model is also validated by a comparison between the calculated plasma density and that measured in the *** electrical model proposed in this work consists of replacing the RF discharge by a passive circuit（resistance in series with a capacitor）,where the resistance represents the plasma medium and the obstruction of the passage of the electronic current,and the capacitor represents the sheaths and the appearance of the displacement current in these *** parameters of the electrical model are obtained through particle *** electrical model presented accurately reproduces the current of the discharge,but without considering the phenomenon of *** total harmonic distortion rate follows the variation of the plasma density;its maximum value is 5.75% at 100 mTorr.

关键词： electrical model least square method particle model radiofrequency discharge static parameters identification

Late Quaternary sinistral slip rate along the Altyn Tagh fault and its structural transformation model

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Science China Earth Sciences 2005年第3期48卷 384-397页

作者： P. Tapponnier J. Van Der Woerd F. J. Ryerson A.S. Meriaux laboratoire de Tectonique Institut de Physique du Globe de Paris FranceLaboratoire de Tectonique Institut de Physique du Globe de Paris FranceIGPP Lawrence Livermore Laboratory Livermore CA 94550 USALaboratoire de Tectonique Institut de Physique du Globe de Paris France

Based on technical processing of high-resolution SPOT images and aerophotos, detailed mapping of offset landforms in combination with field examination and displacement measurement, and dating of offset geomorphic surfaces by using carbon fourteen (14C), cos- mogenic nuclides (10Be+26Al) and thermoluminescence (TL) methods, the Holocene sinistral slip rates on different segments of the Altyn Tagh Fault (ATF) are obtained. The slip rates reach 17.5 ±2 mm/a on the central and western segments west of Aksay Town, 11±3.5 mm/a on the Subei-Shibaocheng segment, 4.8±1.0 mm/a on the Sulehe segment and only 2.2±0.2 mm/a on the Kuantanshan segment, an easternmost segment of the ATF. The sudden change points for loss of sinistral slip rates are located at the Subei, Shibaocheng and Shulehe triple junctions where NW-trending active thrust faults splay from the ATF and propagate southeastward. Slip vector analyses indicate that the loss of the sinistral slip rates from west to east across a triple junction has structurally transformed into local crustal shortening perpendicular to the active thrust faults and strong uplifting of the thrust sheets to form the NW-trending Danghe Nanshan, Daxueshan and Qilianshan Ranges. Therefore, the eastward extrusion of the northern Qing- hai-Tibetan Plateau is limited and this is in accord with “the imbricated thrusting transforma- tion-limited extrusion model”.

关键词： Altyn Tagh Fault, sinistral strike-slip rate, structural transformation, extrusion tectonics.

Optical Constant and Electrical Resistivity of Annealed Sn3Sb2S6 Thin Films

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Acta Metallurgica Sinica(English Letters) 2016年第3期29卷 287-294页

作者： Y.Fadhli A.Rabhi M.Kanzari laboratoire de Photovoltaique et Materiaux Semi-conducteurs-ENIT BP 37 Le belvedere 1002 Tunis Tunisia laboratoire de Photovoltaiques et Materiaux Semi-conducteurs-ENIT-IPEITunis Montfleury Universite de Tunis Tunis Tunisia

In this study,we report the annealing effects on the physical properties of Sn_3Sb_2S_6 thin ***_3Sb_2S_6 thin films were prepared onto non-heated glass substrates via thermal evaporation *** as-deposited films were annealed in air for 1 h in the temperature range from 100 to 300 °C.X-ray diffraction results show that the crystallinity of the thin films increased after *** microstructure parameters crystallite size,dislocation density,lattice strain and stacking fault probability were *** optical properties were obtained from the analysis of the experimental recorded transmittance and reflectance spectral data over the wavelength range 300–1800 *** absorption coefficient（10~5cm^（-1）） reached to the visible and near-IR spectral range.A decrease in optical band gap from 1.92 to 1.71 e V by increasing the air annealing temperature was *** energy E_o and dispersion energy E_d of the films after annealing were estimated according to the model of Wemple–Di Domenico single ***–Fan model was applied to determine the electron free carrier susceptibility and the ratio of carrier concentration to the effective *** layers annealed at temperatures 〉150 ℃ undergo abrupt changes in their electrical properties and exhibit a resistive hysteresis *** properties confer to the material interest perspectives for its application in diverse advanced technologies such as photovoltaic applications and optical storage.

关键词： Thin films Sn_3Sb_2S_6 Optical constants Resistivity Hysteresis

Effect of Scanning Beam Profile to Fabricate Fused Fiber Tapers by CO_2 Laser Irradiation Method

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光学学报 2003年第S1期23卷 121-122页

作者： Bayle Fabien Luo Aiping Marin Emmanuel Meunier Jean-Pierre laboratoire TSI UMR CNRS 5516 Saint Etienne FranceLaboratoire TSI UMR CNRS 5516 Saint Etienne FranceLaboratoire TSI UMR CNRS 5516 Saint Etienne FranceLaboratoire TSI UMR CNRS 5516 Saint Etienne France

Beam uniformity is a crucial building block of CO2 experiments aimed at fusing and stretching optical fibers in a lossless manner. When the irradiation beam is expanded through a galvanometer mirror, ways to achieve b... 详细信息

关键词： of in on as it by Effect of Scanning Beam Profile to Fabricate Fused Fiber Tapers by CO2 Laser Irradiation Method