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Three different low-temperature plasma-based methods for hydrophilicity improvement of polyethylene films at atmospheric pressure

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Chinese Physics B 2013年第11期22卷 411-417页

作者：陈光良郑旭黄俊司晓蕾陈致力薛飞 Sylvain massey Key Laboratory of Advanced Textile materials and manufacturing Technology and Engineering Research Center for Eco-Dyeing & Finishing of Textiles Ministry of Education Zhejiang Sci-Tech University Groupe en sciences des Radiations Faculte' de me'decine et des Sciences de la Sant Universite' de Sherbrooke

Three different low-temperature plasma-based methods were used to improve the surface hydrophilicity of polyethy- lene （PE） films, and all the modification processes were carried out by employing an atmospheric pressure plasma jet （APPJ） system. （a） PE films were directly modified by APPJ using a gas mixture of He and 02. （b） Acrylic acid （AA） was introduced into the system and a polymer acrylic acid （PAA） coating was deposited onto the PE films. （c） AA was grafted onto the PE surface activated by plasma pre-treatment. It was found that the hydrophilicity of the PE films was significantly improved for all the three methods. However, the samples modified by Process （a） showed hydrophobicity recovery after a storage time of 20 days while no significant change was found in samples modified by Process （b） and Process （c）. The Fourier transform infrared spectroscopy （FTIR） results indicated that the most intensive C=O peak was detected on the PE surface modified by Process （c）. According to the X-ray photoelectron spectroscopy （XPS） analysis, the ratios of oxygen-containing polar groups for samples modified by Process （b） and Process （c） were higher than that modified by Process （a）.

关键词： atmospheric pressure plasma jet plasma modification acrylic acid hydrophilicity improvement

Surface Effects on Wannier Excitons in Superlattices:monte Carlo Simulation

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Chinese Physics Letters 2002年第8期19卷 1164-1167页

作者： K. Afif, A. Benyoussef and J. Diouri Laboratoire de magnetisme Faculte des Sciences Groupe d"Electronique et de Physique du Solide Faculte des Science

Using a monte Carlo quadrature, we calculate by a variational method the binding energy Eb of Wannier excitons in N-period m-CdmnTe/n-CdTe superlattices, including or not including the step discontinuity in the potential barrier at the interface, and with varying N as well as well width. The calculation is performed in the framework of the effective mass approximation for both heavy-hole and light-hole excitons. The degree of exciton localization dependence on these parameters is accurately illustrated.

关键词： monte Carlo methods

Satellite monitoring of land-use and land-cover changes in northern Togo protected areas

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Journal of Forestry Research 2014年第2期25卷 385-392页

作者： Fousseni Folega Chun-yu Zhang Xiu-hai Zhao Kperkouma Wala Komlan Batawila Hua-guo Huang marra Dourma Koffi Akpagana The Key Laboratory for Silviculture and Conservation of ministry of Education Beijing Forestry University Université de Lomé Laboratoire de botanique et écologie végétaleFaculté des sciences

Remote-sensing data for protected areas in northern Togo, obtained in three different years （2007, 2000, and 1987）, were used to assess and map changes in land cover and land use for this drought prone zone. The normalized difference vegetation index （NDVI） was applied to the images to map changes in vegetation. An unsupervised classification, followed by classes recoding, filtering, identifications, area computing and post-classification process were applied to the composite of the three years of NDVI images. maximum likelihood classification was applied to the 2007 image （etm＋2007） using a supervised classification process. Seven vegetation classes were defined from training data sets. The seven classes included the following biomes： riparian forest, dry forest, flooded vegetation, wooded savanna, fallows, parkland, and water. For these classes, the overall accuracy and the overall kappa statistic for the classi- fied map were 72.5% and 0.67, respectively. Data analyses indicated a great change in land resources; especially between 1987 and 2000 proba- bly due to the impact of democratization process social, economic, and political disorder from 1990. Wide-scale loss of vegetation occurred during this period. However, areas of vegetation clearing and regrowth were more visible between 2000 and 2007. The main source of confusion in the contingency matrix was due to heterogeneity within certain classes. It could also be due to spectral homogeneity among the classes. This research provides a baseline for future ecological landscape research and for the next management program in the area.

关键词： land change NDVI land cover protected areas Northern Togo

monte Carlo study of nanowire magnetic properties

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Chinese Physics B 2013年第5期22卷 514-518页

作者： R. masrour L. Bahmad A. Benyoussef Laboratoire de magnétisme et Physique des Hautes Energies URAC 12Université Mohammed V-AgdalFaculté des Sciences Laboratory of materials ProcessEnvironment and QualityCady Ayyad UniversityNational School of Applied Sciences

In this work, we use monte Carlo simulations to study the magnetic properties of a nanowire system based on a honeycomb lattice, in the absence as well as in the presence of both an external magnetic field and crystal field. The system is formed with NL layers having spins that can take the values σ= ± 1/2 and S =±1,0. The blocking temperature is deduced, for each spin configuration, depending on the crystal field A. The effect of the exchange interaction coupling Jp between the spin configurations σ and S is studied for different values of temperature at fixed crystal field. The established ground-state phase diagram, in the plane （Jp, △）, shows that the only stable configurations are：（1/2,0）, （1/2, ＋1）, and （1/2,- 1）. The thermal magnetization and susceptibility are investigated for the two spin configurations, in the absence as well as in the presence of a crystal field. Finally, we establish the hysteresis cycle for different temperature values, showing that there is almost no remaining magnetization in the absence of the external magnetic field, and that the studied system exhibits a super-paramagnetic behavior.

关键词： monte Carlo simulations nanowire magnetic field crystal field

Natural frequencies of composite beams with a variable fiber volume fraction including rotary inertia and shear deformation

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Applied mathematics and mechanics(English Edition) 2009年第6期30卷 717-726页

作者： Y. Bedjilili A. Tounsi H. m. Berrabah I. mechab E. A. Adda Bedia S. Benaissa Université de Tlemcen Faculté des Sciences de l'ingénieurDépartement de Génie MécaniqueAlgérie Laboratoire des matériaux et Hydrologie Université de Sidi Bel AbbesAlgérie Laboratoire de mathématiques Université de Sidi Bel AbbesAlgérie

The present study is concerned with the vibration analysis of symmetric composite beams with a variable fiber volume fraction through thickness. First-order shear deformation and rotary inertia have been included in the analysis. The solution procedure is applicable to arbitrary boundary conditions. Continuous gradation of the fiber volume fraction is modeled in the form of an m-th power polynomial of the coordinate axis in the thickness direction of the beam. By varying the fiber volume fraction within the symmetric composite beam to create a functionally graded material （FGm）, certain vibration characteristics are affected. Results are presented to demonstrate the effects of shear deformation, fiber volume fraction, and boundary conditions on the natural frequencies and mode shapes of composite beams.

关键词： free vibration functionally graded materials first-order shear deformationtheory

biomechanical models and Experi ments in Bone Tissue Engineering

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生物医学工程学杂志 2005年第S1期22卷 11-12页

作者： Christian ODDOU Julien PIERRE Karim OUDINA Hervé PetITE faculté des sciences Université Paris 12 61 av. Général de Gaulle CRETEIL CedexFranceFaculté des Sciences Université Paris 12 61 av. Général de Gaulle CRETEIL CedexFranceFaculté de Médecine Université Paris 7 10 av .de Verdun PARIS FranceFaculté de Médecine Université Paris 7 10 av .de Verdun PARIS France

On the Equivalence of Weyl Theorem and Generalized Weyl Theorem

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Acta mathematica Sinica,English Series 2007年第1期23卷 103-110页

作者： m.BERKANI Grouped'Analyse et Théorie des Opérateurs(G.A.T.O.) Département de MathématiquesUniversitéMohammed ⅠFaculté des SciencesOujda 60000Morocco

We know that an operator T acting on a Banach space satisfying generalized Weyl＇s theorem also satisfies Weyl＇s theorem. Conversely we show that if all isolated eigenvalues of T are poles of its resolvent and if T satisfies Weyl＇s theorem, then it also satisfies generalized Weyl＇s theorem. We give also a sinlilar result for the equivalence of a-Weyl＇s theorem and generalized a-Weyl＇s theorem. Using these results, we study the case of polaroid operators, and in particular paranormal operators.

关键词： B-Fredholm operator Weyl's theorem generalized Weyl's theorem a-Weyl's theorem,generalized a-Weyl's theorem poles

Generalized Coherent States of a Particle in a Time-dependent Linear Potential

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Chinese Physics Letters 2009年第7期26卷 36-39页

作者： L. Krache m. maamache Y. Saadi A. Beniaiche Lab PQSD Faculté des Sciences Université Ferhat Abbas de Sétif Sétif 19000 Algeria Lab SPONL Faculté des Sciences de l'Ingénieur Université Ferhat Abbas de Sétif Sétif 19000 Algeria

We derive, with an invariant operator method and unitary transformation approach, that the Schr6dinger equation with a time-dependent linear potential possesses an infinite string of shape-preseving wave-packet states 1φ,λ （t） having classical motion. The qualitative properties of the invariant eigenvalue spectrum （discrete or continuous） are described separately for the different values of the frequency ω of a harmonic oscillator. It is also shown that, for a discrete eigenvalue spectrum, the states 1φ,λ （t） could be obtained from the coherent state 1φ,λ （t）.

关键词： mathematical physics Quantum information and quantum mechanics

Adsorption properties of Rosmarinus officinalis oil as green corrosion inhibitors on C38 steel in 0.5 m H_2SO_4

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Acta metallurgica Sinica(English Letters) 2010年第1期23卷 13-20页

作者： E.El Ouariachi J.Paolini m.Bouklah A.Elidrissi A.Bouyanzer B.Hammouti J-m.desjobert J.Costa Laboratoire de Chimie Appliqu'ee et Environnement Facult'e des SciencesUniversit'e Mohamed PremierBP71760000 OujdaMorocco UmR CNRS 6134 Laboratoire de Chimie des Produits NaturelsUniversit'e de CorseFrance

Rosmarinus officinalis essential oil obtained by hydrodistillation was tested as corrosion inhibitor of steel in 0.5 m H2SO4 using weight loss measurements, and electrochemical .polarisation methods. Results obtained indicate that the corrosion rate is reduced and R. officinalis oil adsorbs on the metal surface and then inhibits corrosion process. Its inhibition efficiency increases with oil increasing content to reach 61% at 1 g/L. Polarisation curves indicate that RO acts as a cathodic inhibitor. The inhibition efficiency of naturally oil remains slightly constant with the rise of temperature. Chemical analysis of R. officinalis essential oil was carried out using capillary GC and GC/mS. The oil composition was characterized by high amount of oxygenated monoterpene （77%） with 1,8-cineol （52.1%） as main component. Discussion of adsorption was investigated on the the isotherm adsorption of essential oil on basis of essential oil composition. Finally the steel has been also reported.

关键词： Rosmarinus officinalis oil Adsorption Corrosion Inhibition Steel 1,8-cineol