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Free vibration of functionally graded sandwich plates using four-variable refined plate theory

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Applied Mathematics and Mechanics(English Edition) 2011年第7期32卷 925-942页

作者： L.HAdJI H.A.ATMANE A.TOUNSI I.MECHAB E.A.AddA BEdIA Laboratoire des Matériaux et Hydrologie Université de Sidi Bel AbbesSidi Bel Abbes 22000Algérie département de Génie Civil Université Ibn KhaldounTiaret 14000Algérie département de Génie Civil Faculté des Sciences de l'IngénieurUnivesité Hassiba Benbouali de ChlefChlef 02000Algérie

This paper uses the four-variable refined plate theory （RPT） for the free vibration analysis of functionally graded material （FGM） sandwich rectangular plates. Unlike other theories, there are only four unknown functions involved, as compared to five in other shear deformation theories. The theory presented is variationally consistent and strongly similar to the classical plate theory in many aspects. It does not require the shear correction factor, and gives rise to the transverse shear stress variation so that the transverse shear stresses vary parabolically across the thickness to satisfy free surface conditions for the shear stress. Two common types of FGM sandwich plates are considered, namely, the sandwich with the FGM facesheet and the homogeneous core and the sandwich with the homogeneous facesheet and the FGM core. The equation of motion for the FGM sandwich plates is obtained based on Hamilton＇s principle. The closed form solutions are obtained by using the Navier technique. The fundamental frequencies are found by solving the eigenvalue problems. The validity of the theory is shown by comparing the present results with those of the classical, the first-order, and the other higher-order theories. The proposed theory is accurate and simple in solving the free vibration behavior of the FGM sandwich plates.

关键词： functionally graded material (FGM) free vibration sandwich plate refinedplate theory (RPT) Navier solution

Manifolds with Bakry-Emery Ricci Curvature Bounded Below

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Advances in Pure Mathematics 2016年第11期6卷 754-764页

作者： Issa Allassane Kaboye Bazanfaré Mahaman Faculté de Sciences et Techniques Université de Zinder Zinder Niger département de Mathématiques et informatique Université Abdou Moumouni Niamey Niger

In this paper we show that, under some conditions, if M is a manifold with Bakry-émery Ricci curvature bounded below and with bounded potential function then M is compact. We also establish a volume comparison theorem for manifolds with nonnegative Bakry-émery Ricci curvature which allows us to prove a topolological rigidity theorem for such manifolds.

关键词： Bakry Émery Ricci Curvature Myers Theorem Volume Comparison Theorem Topological Rigidity Theorem

On Non-Abelian Extensions of 3-Lie Algebras

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Communications in Theoretical Physics 2018年第4期69卷 347-356页

作者： Li-Na Song Abdenacer Makhlouf Rong Tang department of Mathematics Jilin University Changchun 130012 China University of Haute Alsace Laboratoire de Math~matiques Informatique et Applications Mulhouse France

In this paper, we study non-abelian extensions of 3-Lie algebras through Maurer-Cartan elements. We show that there is a one-to-one correspondence between isomorphism classes of non-abelian extensions of 3-Lie algebras and equivalence classes of Maurer-Cartan elements in a dGLA. The structure of the Leibniz algebra on the space of fundamental objects is also analyzed.

关键词： 3-Lie algebras Leibniz algebra non-abelian extension Maurer-Cartan element

A physically based algorithm for land surface emissivity retrieval from combined mid-infrared and thermal infrared data

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Science China(Technological Sciences) 2000年第S1期43卷 23-33页

作者：李召良张仁华 F.Petitcolin Laboratoire des Sciences de l’Image de l’Informatique et de la Teledetection Illkirch France Institute of Geography Chinese Academy of Sciences Beijing China

On the basis of the concept of the two-channel Temperature-Independent Spectral Indices (TISI), a physically based method is developed to extract the directional emissivities in mid-infrared and thermal infrared channels from day-night space measurements. A phenomenol-ogical model with three parameters is also proposed in this paper to describe the angular variations of the reflectivity (or emissivity). Having applied the proposed method to AVHRR data on an area covering the Iberian Peninsula (rather vegetated) and on a region centered on Tunisia (arid area), one can see from the results that the terrestrial surfaces do not behave as Lambertian reflector and angular variations of bidirectional reflectivity for bare soils appear to be azimuth-independent whereas those for vegetation present a pronounced backscattering effect. As for directional emissivities, values of vegetated areas are found to be higher and remain rather constant whatever the view angle is. On the contrary, on arid areas, values are found to be rather low and present significant angular variations.

关键词： land surface emissivity bidirectional reflectivity TISI.

Morphology and Photoelectrochemical Characterization of MEH-PPV/PCBM Composite Film doped with TiO_2 Nanoparticles

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Acta Metallurgica Sinica(English Letters) 2013年第4期26卷 373-377页

作者： Farid Habelhames Zerguine Wided Leila Lamiri Belkacem Nessark Hassina derbal-Habak Laboratoire d'lectrochimie et matriaux(LEM) Facult de Technologie.Dpartement de gnie des Universit Ferhat Abbas Stif 119000Algrie ECOLE POLYTECHNIQUE LPICM LaboratoryORGATECH Team Route de Saclay ParisFrance

Poly[2-methoxy-5-（20-ethylhexyloxy）-io-phenylenevinylene] （MEH-PPV）, [6,6]-phenyl-C61-butyric acid methyl ester （PCBM） and titanium dioxide （TiO2） nanoparticles （n-type） were dissolved, mixed and deposited by physical methods （spin-coating） on indium tin-oxide （ITO） substrate. The incorporation of the titanium dioxide nanoparticles changed the morphology and increased the roughness of polymers film （MEH-PPV/PCBM）, and the photocurrent density of the composite （MEH-PPV/PCBM ＋n-TiO2） was higher than that of single MEH- PPV/PCBM film. The study showed that the presence of n-TiO2 particles in the polymeric film improves the photoelectrochemical properties of M EH-PPV/PCBM composite.

关键词： Photocurrent density Electrochemical property Hybrid coating Conducting polymer Titanium dioxide Organic nanostructures

Practical stabilization of a class of uncertain time-varying nonlinear delay systems

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控制理论与应用（英文版） 2009年第2期7卷 175-180页

作者： Bassem Ben HAMEd Mohamed Ali HAMMAMI Institut Supérieur des Sciences Appliquées et de Technologie de Gabès Département de MathématiquesRue Amor Ben El Khatab 6029 GabèsTunisia Faculté des Sciences de Sfax Département de Mathématiques BP 802 Route Soukra km 4 Sfax 3018Tunisia

In this paper we deal with a class of uncertain time-varying nonlinear systems with a state delay. Under some assumptions, we construct some stabilizing continuous feedback, i.e. linear and nonlinear in the state, which can guarantee global uniform exponential stability and global uniform practical convergence of the considered system. The quadratic Lyapunov function for the nominal stable system is used as a Lyapunov candidate function for the global system. The results developed in this note are applicable to a class of dynamical systems with uncertain time-delay. Our result is illustrated by a numerical example.

关键词： Nonlinear system Time-delay Feedbacks Practical convergence Lyapunov function

A quantum cascade laser infrared spectrometer for CO_2 stable isotope analysis：Field implementation at a hydrocarbon contaminated site under bio-remediation

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Journal of Environmental Sciences 2016年第2期28卷 60-74页

作者： Christophe Guimbaud Cécile Noel Michel Chartier Valéry Catoire Michaela Blessing Jean Christophe Gourry Claude Robert Laboratoire de Physique et de Chimie de l'Environnement et de l'Espace (LPC2E) CNRS et Universite d'Orleans (UMR 7328)45071 Orleans cedex 2 France Bureau de Recherches Geologiques et Minieres (BRGM) 45060 Orleans cedex 2 France

Real-time methods to monitor stable isotope ratios of CO_2 are needed to identify biogeochemical origins of CO_2 emissions from the soil–air interface. An isotope ratio infra-red spectrometer（IRIS） has been developed to measure CO_2 mixing ratio with δ~13C isotopic signature, in addition to mixing ratios of other greenhouse gases（CH_4, N2_O）. The original aspects of the instrument as well as its precision and accuracy for the determination of the isotopic signature δ~13C of CO_2 are discussed. A first application to biodegradation of hydrocarbons is presented, tested on a hydrocarbon contaminated site under aerobic bio-treatment. CO_2 flux measurements using closed chamber method is combined with the determination of the isotopic signature δ~13C of the CO_2 emission to propose a non-intrusive method to monitor in situ biodegradation of hydrocarbons. In the contaminated area, high CO_2 emissions have been measured with an isotopic signature δ~13C suggesting that CO_2 comes from petroleum hydrocarbon *** first field implementation shows that rapid and accurate measurement of isotopic signature of CO_2 emissions is particularly useful in assessing the contribution of contaminant degradation to the measured CO_2 efflux and is promising as a monitoring tool for aerobic bio-treatment.

关键词： Isotope ratio infrared spectrometry Isotopic signature δ^(13)C of CO_2 Biodegradation monitoring Hydrocarbons BTEX

Utilisation du système d’information géographique et modèle numérique de terrain dans l’analyse des caractéristiques hydro-morphométriques des sous-bassins versants de la rivière Tshopo,République démocratique du Congo Use of Geographic Information System and digital Elevation Model to Analyze the Hydro-Morphometric Characteristics of the Tshopo River Sub-Catchments,democratic Republic of Congo

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Revue Internationale de Géomatique 2023年第1期32卷 99-122页

作者： Faidance Mashauri Mokili Mbuluyo Nsalambi Nkongolo département de Géologie Facultédes Sciences et TechnologiesUniversitéde l’UéléIsiroBP 670République démocratique du Congo département de Sciences du Sol et de l’Eau Institut Facultaire des Sciences Agronomiques(IFA)de YangambiKisanganiBP 1232République démocratique du Congo département de Géologie Facultédes Sciences et TechnologiesUniversitéde KisanganiKisanganiBP 2012République démocratique du Congo Geographic Information Technology Program School of ScienceNavajo Technical UniversityCrownpointNew MexicoUSA

The analysis and quantification of hydro-morphometric characteristics are essential for better management of water resources and more effective planning of hydroelectric projects in the Tshopo ***,few studies have been carried out to assess these characteristics at the scale of this *** methodological approach consists of using Geographic Information System(GIS)software analysis tools applied to the digital Elevation Model(deM)derived from the Advanced Land Observing Satellite(ALOS)World 3d-30m *** enabled us to automatically extract the hydrographic network and generate the Tshopo *** results of this analysis show that the Tshopo catchment area is of the order of magnitude 7.A total of 8 sub-watersheds were identified,covering an area of around 19,335 *** are elongated in shape,with a coefficient of compactness(KG)of between 1.84 and *** slopes are low,ranging from 0.84%to 3.58%.Run-off velocity is generally low,with a velocity range(Ve)of 2.3 to 4.79 km/*** duration of run-off concentration(Tc)varies between 30.2 and 70.2 h in the tributaries of the *** hydrographic network is dense,with drainage densities(dd)ranging from 0.91 to 1.72 km/*** watercourses form a homogeneous dendritic network,but with local *** some places,the network can take on a parallel or rectangular shape.

关键词： Morphometry deM GIS hypsometry hydrographic network sub-catchments Tshopo river

Revealing of major factors in the directional thermal radiation of ground objects——A new way for improving the precision of directional radiant temperature measuring and data analysis

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Science China(Technological Sciences) 2000年第S1期43卷 34-40页

作者：张仁华孙晓敏李召良苏红波唐新斋 M.P.Stoll Institute of Geography Chinese Academy of Sciences Beijing China Laboratoire des Sciences de I’Image de I’Informatique et de la Teledetection Illkrich France

This paper is devoted to eliminating the noise from the measuring of directional thermal radiation for ground objects. Specifically, we think that the noise is mainly due to the variance of components in the field of view of the sensor with the view angle changing and to the heat balance change on the ground during the period of measurement. The authors present two new observation methods named as "constant area method by thermal camera" and "concurrent method by dual sensors" respectively. The experiments show that the data obtained by these methods abide by some regularly directional distribution, which is totally different from the data from the former methods. The analysis of the major factors in the directionality of thermal radiation is also made in the paper.

关键词： radiant temperature directionality constant area method by thermal camera concurrent method by dual sensors.