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Degradation of direct azo dye by Cucurbita pepo free and immobilized peroxidase

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Journal of Environmental Sciences 2013年第6期25卷 1235-1244页

作者： Nabila Boucherit Mahmoud Abouseoud Lydia Adour Université Mouloud Mammeri laboratoire de Biomatériaux et de Phénomènes deTransports Université Dr.Yahia Fares laboratoire de Biomatériaux et de Phénomènes de Transports Université Dr.Yahia Fares laboratoire de Génie de la Réaction Faculté de Génie Mécanique et Génie des ProcédésUniversité Houari Boumediene laboratoire des Biotechnologies Environnementales et Génie des Procédés

Enzymatic decolourization of the azo dye, Direct Yellow （DY 106） by Cucurbita pepo （courgette） peroxidase （CP） is a complex process, which is greatly affected by pH, temperature, enzyme activity and the concentrations of H202 and dye. Courgette peroxidase was extracted and its performance was evaluated by using the free-CP （FCP） and immobilized-CP （ICP） forms in the decolourization of DY106. Immobilization of peroxidase in calcium alginate beads was performed according to a strategy aiming to minimize enzyme leakage and keep its activity at a maximum value by optimizing sodium alginate content, enzyme loading and calcium chloride concentration. The initial conditions ~it which the highest DY106 decolourization yield was obtained were found at pH 2, temperature 20~C, H202 dose 1 mmol/L （FCP） and 100 mmol/L （ICP）. The highest decolourization rates were obtained for dye concentrations 50 mg/L （FCP） and 80 mg/L （ICP）. Under optimal conditions, the FCP was able to decolorize more than 87% of the dye within 2 min. While with ICP, the decolourization yield was 75% within 15 rain. The decolourization and removal of DY106 was proved by UV-Vis analysis. Fourier transform infrared （FF-IR） spectroscopy analysis was also performed on DY106 and enzymatic treatment precipitated byproduct.

关键词： Cucurbita pepo peroxidase immobilization decolourization azo dye

Capillary effect on the sloshing of a fluid in a rectangular tank submitted to sinusoidal vertical dynamical excitation

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Journal of Hydrodynamics 2014年第2期26卷 326-338页

作者： MEZIANI Bachir OURRAD Ouerdia laboratoire de Physique Théorique Université A. Mira de Bejaia Campus de targua Ouzemour

Surface tension effects on fluid sloshing in a tank subjected to external excitation has been less studied. This work aims at understanding this phenomenon in order to derive practical solutions to problems faced in several engineering. A tank containing a fluid with a free surface is submitted to gravity and capillary forces and subject to external dynamic excitation. Introduction of vertical sinusoidal dynamical excitation leads to a problem of paramtric oscillations governed by the Mathieu equation. Analysis of the Mathieu equation shows the existence of stable and unstable regions in the stability diagram. Some results induced by harmonic excitations on the fluid sloshing are presented. When the external dynamical excitation amplitude ~ is small, periodic solutions appear in stable regions and when e increases, the fluid behavior is not perfectly periodic and the amplitudes are not regular. Nonlinear effects make the behavior of the fluid complicated and render it almost unpredictable. In stable regions, the solution remains bounded at any time. When changing the perturbation parameter 6, the phase difference increases and also with the increase of the surface tension.

关键词： parametric sloshing capillary effects stability

Small dissymmetry, yet large effects on the transport propertiesof electrolytes based on imide salts: Consequences on performancein Li-ion batteries

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Journal of Energy Chemistry 2022年第2期31卷 352-366页

作者： Joseph Chidiac Laure Timperman Mérièm Anouti laboratoire PCM2E Universitéde ToursParc de Grandmont37200 ToursFrance

To gain better insight into the influence of the anion size and symmetry on the transport properties and thermal stability of an electrolyte based on lithium(fluorosulfonyl)(trifluoromethanesulfonyl)-imide(FTFSI)salt,we performed the physical and electrochemical characterization of an electrolyte based on FTFSI incorporated in standard binary(3 EC/7 EMC)and ternary(EC/PC/3 DMC)alkylcarbonate *** applying the Jones-Dole-Kaminsky(JDK),Eyring and Arrhenius empirical models to the electrolyte viscosity we show that the activation enthalpy and entropy energy barriers(ΔH≠,ΔS≠)for viscous flow are between 12 and 15 kJ·mol^(-1).They are strongly dependent on the solvent nature and are significantly lower than their symmetric anions LiFSI and LiTFSI(19-20 kJ·mol^(-1))in the binary ***,the hydrodynamic radius,rs,calculated by JDK,and the ionicity behavior illustrated by the Walden role,showed that the FTFSI anion is outside the solvation sphere(rs>0.6 nm)which is smaller in the case of an EC/EMC solvent *** the 3 EC/7 EMC solvent mixture,LiFTFSI is less conductive than in the ternary mixture i.e.,σ_(max)=8.9 mS cm^(-1) at C_(max)=1.1 mol L^(-1) for 3 EC/7 EMC and,σ_(max)=10.5 mS cm^(-1) at max=0.7 mol L^(-1) for EC/PC/3 DMC,due to a strong solvation and a greater association of FTFSI ions in the binary solvent *** thermal stability of FTFSI based electrolytes was determined by the shift of the evaporation temperature of the volatile solvents(DMC,EMC)in the presence of salt,towards the higher *** feature is visible on the thermograms obtained by DSC both with the liquid electrolyte and with charged LMO cathodes in presence of *** consequences of these properties on the electrochemical behavior of a graphite(Gr)half-cell,a lithium metal(Li)anode and a manganese lithium oxide(LMO)cathode demonstrated on the one hand the formation of a thick solid electrolyte interphase(SEI)on graphite that consumed a significant amou

关键词： LiFTFSI Electrolyte Viscosity Interface Li-ion battery

THz Generation by Optical Rectification and Competition with Other Nonlinear Processes

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Chinese Physics Letters 2008年第5期25卷 1868-1870页

作者：赵振宇 HAMEAU Sophie TIGNON JerSme laboratoire Pierre Aigrain Ecole Normale Supdrieure 24 rue Lhomond F-75005 Paris France

We present a study of the competition between tera-hertz （THz） generation by optical rectification in （110） ZnTe crystals, two-photon absorption, second harmonic generation and free-carrier absorption. The two-photon nonlinear absorption coefficient, second harmonic generation efficiency and free-carrier absorption coefficient in the THz range are measured independently. The incident pump field is shown to be depleted by two-photon absorption and the THz radiation is shown to be reduced, upon focusing, by free-carrier absorption. The reduction of the generated THz radiation upon tight focusing is explained, provided that one also takes into account diffraction effects from the sub-wavelength THz source.

关键词： supernova explosion proto-neutron star shock wave

Numerical Study of Natural Convection in an Inclined Porous Cavity

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Fluid Dynamics & Materials Processing 2022年第5期18卷 1389-1397页

作者： Saad Adjal Sabiha Aklouche-Benouaguef Belkacem Zeghmati laboratoire des Transports Polyphasiques et Milieux Poreux LTPMPALGER16111ALGERIE laboratoire des Mathématiques et Physique des Systèmes LAMPSPerpignan66860France

Two-dimensional transient laminar natural convection in a square cavity containing a porous medium and inclined at an angle of 30°is investigated *** vertical walls are differentially heated,and the horizontal walls are *** effect of Rayleigh number on heat transfer and on the road to chaos is *** natural heat transfer and the Darcy Brinkman equations are solved by using a finite volume method and a Tri Diagonal Matrix Algorithm(TDMA).The results are obtained for a porosity equal to 0.45,a Darcy number and a Prandtl respectively equal to 10^(-3)and 0.71;they are analyzed in terms of streamlines,isotherms,phase portrait,attractors,and spectra amplitude as a function of the Rayleigh *** is found that,as Rayleigh number increases,the natural convection changes from a steady state to a time-periodic state and finally to a chaotic condition.

关键词： Natural convection porous medium finite volumes chaos attractors

Some Uniqueness Results for Functional Damped Semilinear Differential Equations in Fréchet Spaces

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Acta Mathematica Sinica,English Series 2008年第1期24卷 95-106页

作者： Abdelghani OUAHAB laboratoire de Mathématiques Universitéde Sidi Bel Abbès BP 89

A recent nonlinear alternative for contraction maps in Frechet spaces due to Frigon and Granas （Resultats de type Leray-Schauder pour des contractions sur des espaces de Frechet, Ann. Sci. Math. Quebec 22, （2）, 161-168 （1998））, combined with semigroup theory, is used to investigate the existence and uniqueness of mild solutions for first- and second-order functional semi linear and neutral damped differential equations in Frechet space.

关键词： differential equations damped semigroup family cosinus mild solution fixed point uniqueness Frechet spaces contraction

Morphology and geochemistry of zircon: a case study on zircon from the microgranitoid enclaves

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Science China Earth Sciences 1999年第5期42卷 544-552页

作者：汪相 KIENAST Jean-Robert laboratoire de Petrologie Universite de Paris Ⅶ 75252-Paris Cedex 05

There are three types of zircon (i.e. Zircon A, Zircon B and Zircon C) in the microgranitoid enclaves from the Qingtian granite. Zircon A is of the smallest Ipr, Ipy and Iel values with the largest range of variations; Zircon C is of the largest Ipr, Ipy and Iel values with the smallest range of variations; and Zircon B is intermediate among the three types. The microprobe analysis of zircon demonstrates that the contents of trace elements (Hf, U, Y, Th) increase progressively with larger and larger variation from Zircon A through Zircon B to Zircon C. These characters snggest that the three types of zircon in the enclaves may have formed successively during the cooling mess of enclave magma, corresponding to different sites along with the intrusion of enclave magma. Because of positive correlations of the UO2/HfO2ratio with Ipr, the Th02/Y203 ratio with Ipy, and the UO2/(ThO2+Y203) ratio with Iel, it is suggested that the variation in zircon typology is caused by selective substitution of trace elements on different surfaces of zircon. On the basis of enclave petrology and zircon typomorphism, it is believed that the enclave magma may be generated from partial melting of residual materials in deep regions where the granitic magma has been extracted.

关键词： zircon typology trace elements microgranitoid enclaves.

Late Quaternary clay minerals off Middle Vietnam in the western South China Sea: Implications for source analysis and East Asian monsoon evolution

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Science China Earth Sciences 2007年第11期50卷 1674-1684页

作者： Christophe COLIN laboratoire IDES UMR 8148 CNRS Université de Paris XI Orsay 91405 France

High-resolution clay mineral records combined with oxygen isotopic stratigraphy over the past 450 ka during late Quaternary from Core MD05-2901 off Middle Vietnam in the western South China Sea are re-ported to reconstruct a history of East Asian monsoon evolution. Variations in Illite, chlorite, and kaolinite contents indicate a strong glacial-interglacial cyclicity, while changes in smectite content present a higher frequency cyclicity. The provenance analysis indicates a mixture of individual clay minerals from various sources surrounding the South China Sea. Smectite derived mainly from the Sunda shelf and its major source area of the Indonesian islands. Illite and chlorite originated mainly from the Mekong and Red rivers. Kaolinite was provided mainly by the Pearl River. Spectral analysis of the kaolin-ite/(illite+chlorite) ratio displays a strong eccentricity period of 100 ka, implying the ice sheet-forced win-ter monsoon evolution; whereas higher frequency changes in the smectite content show an ice sheet-forced obliquity period of 41 ka, and precession periods of 23 and 19 ka and a semi-precession period of 13 ka as well, implying the tropical-forced summer monsoon evolution. The winter monsoon evolution is generally in coherence with the glacial-interglacial cyclicity, with intensified winter monsoon winds during glacials and weakened winter monsoon winds during interglacials; whereas the summer monsoon evolution provides an almost linear response to the summer insolation of low latitude in the Northern Hemisphere, with strengthened summer monsoon during higher insolation and weakened summer monsoon during lower insolation. The result suggests that the high-latitude ice sheet and low-latitude tropical factor could drive the late Quaternary evolution of East Asian winter and summer monsoons, respectively, implying their diplex and self-contained forcing mechanism.

关键词： clay minerals,provenance,East Asian monsoon,late Quaternary,Middle Vietnam,South China Sea

Zwitterionic and mesoionic liquids:Molecular aggregation in 3-methylsydnone

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Science China Chemistry 2010年第9期53卷 2063-2069页

作者： CASSEL Stéphanie RICO-LATTES Isabelle LATTES Armand laboratoire des IMRCP UMR 5623Université Paul Sabatier

Ionic liquids are green solvents with interesting properties:displaying low melting points and high boiling *** offer a new approach applicable in many ***,the presence of free ions can be a matter in some cases,*** the study of nucleophilic reactions,in electrochemistry,and in each situation where there is a competition between counter ions,as in micellization of ionic *** compounds having formal unit electrical charges of opposite sign,and the same physical properties than ionic liquids would be a nice alternative to these latter *** are two classes of chemical compounds having these characteristics:zwitterionic liquids(with no uncharged canonical representation) and mesoionic liquids(in which the negative and the positive charges are delocalized).In that last class we have chosen to work with 3-methylsydnone in order to examine,in this aprotic solvent,if it was possible to observe aggregation of surfactants in the same manner as in *** all kinds of surfactants studied(ionic,zwitterionic and mesoionic) we have been able to demonstrate the formation of direct micelles:hydrogen bonding is thus not mandatory for molecular *** of the behavior in water and in formamide showed that solvophobic interactions were qualitatively comparable but with a lower intensity.

关键词： ionic liquids zwitterionic liquids mesoionic liquids 3-methylsydnone molecular aggregation micellization solvophobicity