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Graphene Thin Layers Formation on Monocrystalline Ni(111)/MgO(111) by Carbon Implantation and Annealing

Graphene 2015年第2期4卷 21-37页

作者： F. Le Normand M. Benyahia C. Speisser D. Muller F. Aweke G. Gutierrez J. Arabski G. Morvan ICube—Laboratoire des Sciences de l’Ingénieur de l’Informatique et de l’Imagerie Université de Strasbourg Strasbourg Cedex France IPCMS—institut de physique et de Chimie des Matériaux de Strasbourg Strasbourg Cedex France LHyGeS—Laboratoire d’Hydrologie et de Géochimie de Strasbourg Strasbourg Cedex France

The objectives of this study are the elaboration of graphene by 1) carbon implantation at moderate temperature (873 K) into a monodomain epitaxially-grown Ni(111) film deposited on a reusable MgO(111) substrate, followed by 2) carbon surface precipitation by thermal treatment. The growth of the nickel film by molecular beam epitaxy has been monitored by Reflection High Energy Electron Diffraction. The film morphology has been studied by Electron Back-Scattered Diffraction, Atomic Force Microscopy and Rutherford Backscattering Spectroscopy in the tunneling mode. In the optimized conditions corresponding to a germination step at 633 K followed by a step growth at 873 K and a post-annealing treatment at 1023 K monocrystalline Ni(111) //MgO(111) films are prepared, exhibiting monodomain swith high structural and orientation qualities. 13C implantation into these nickel films is subsequently achieved at 873 K with energy within 20 - 50 keV and a carbon dose equivalent to 4 monolayers of graphene (1.4 × 1016 at/cm2). Carbon diffuses mainly towards the surface, forming thin layers graphene. Compared to a Ni polycrystalline film the graphene fragments are larger and better facetted. The carbon amounts inside the nickel films at different steps, as well as the carbon amount at the surface, have been measured by Nuclear Reaction Analysis and X-ray Photoelectron Spectroscopy, respectively. The results show that, in addition to implanted 13C, some amounts of 12C is incorporated at different steps of the process and is involved in the formation of the graphene monolayers, as shown by 13C/12C Raman mappings. We finally discuss different mechanisms for carbon diffusion and surface segregation, considering the size and thickness distributions of the thin-layers graphene.

关键词： Graphene Nickel Monocrystalline Films Ion Implantation Raman Spectroscopy

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Estimation of Methane Emission from Kossihouen Sanitary Landfill and Its Electricity Generation Potential (Côte d’Ivoire)

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Journal of Power and Energy Engineering 2018年第7期6卷 22-31页

作者： Kouakou Adjoumani Rodrigue Kra Essi Kouadio Marc Cyril Trokourey Albert Laboratoire de Chimie physique Université Félix Houphouet-Boigny Abidjan Cote d’Ivoire Laboratoire de Mécanique et des Sciences des Matériaux Institut National Polytechnique Felix Houphouet Boigny (INPHB) Yamous-soukro Cote d’Ivoire

In order to solve the problem of the management of municipal solid waste in Abidjan (Cote d’Ivoire), a sanitary landfill has been designed in Kossihouen. despite the adverse greenhouse effects of the methane, this gas has a potential of electrical energy. The estimation of methane emissions from the waste can be an economic and useful way for more accurate control and management of waste disposal in Kossihouen. Therefore, conducting this study is essential. Methane emissions were estimated based on the methane generation constant K and the methane generation potential L0 using LandGEM 3.02. The results show that the quantity of methane emissions was 7.97E+07 m3/year. Based on this result, the methane content can generate 10% of total electricity consumed in Abidjan in 2026. This paper could serve as a source of scientific information for decision making on environmental sustainability in waste-to-energy projects in Cote d’Ivoire.

关键词： Methane LandGEM Kossihouen Landfill Gas

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A Novel Bow-Tie Antenna with Triple Band-Notched Characteristics for UWB Applications

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Journal of Electromagnetic Analysis and Applications 2016年第12期8卷 271-282页

作者： Abdoulaye Chaibo Assane Ngom Mahamoud Youssouf Khayal Kharouna Talla Aboubaker Chedikh Beye Groupe de Laboratoires de physique des Solides et Science des Matériaux (GLPSSM) Département de Physique Université Cheikh Anta Diop de Dakar Sénégal Département des Télécommunications et Multimédia (DTM) Institut National Supérieur des Sciences et Techniques d’Abéché Tchad Université Cô te d’Azur CNRS LEAT Sophia Antipolis France Centre National de Recherche pour le Développement (CNRD) N’Djamena Tchad

This paper presents the design of a compact bow-tie antenna with triple band notched characteristics for UWB applications. The proposed antenna can operate from 3.1 to 10.6 GHz with VSWR - 8.4 GHz) centered at 8.1 GHz, the CSRR2 rejects the WLAN band (5.15 - 5.85 GHz) centered at 5.6 GHz, and the CSRR3 rejects the band (4.10 - 4.47 GHz) centered at 4.32 GHz. Compared with recent design, this antenna is more compact, and presents better simulation results of its characteristics. Our newly designed antenna is a potential candidate for application in UWB communication systems.

关键词： Bow-Tie Antenna Ultra Wide Band (UWB) Antenna CSRRs Notch Band

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Experimental Alternative to the determination of the Thermal dependence of the Complex Modulus of Asphalt Mixes in Dry Tropical Areas

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Journal of Minerals and Materials Characterization and Engineering 2022年第3期10卷 275-286页

作者： Sidpouita Mathilde Koudougou Guy Christian Tubreoumya David Yemboini Kader Toguyeni Tégawendé Justin Zaida institut de Génie des Systèmes Industrielles de Textiles Ecole Polytechnique de Ouagadougou Ouagadougou Burkina Faso Laboratoire de physique et de Chimie de l’Environnement Ouagadougou Burkina Faso Université Joseph Ki-Zerbo Ouagadougou Burkina Faso

Current pavement design methods do not allow for the reduction of early deformation of the surface layers of bituminous pavements in the city of Ouagadougou. Weather conditions combined with traffic, particularly during heat waves, are factors. The temperature at the surface of the bituminous pavement can reach 62˚C but the complex modulus associated with this temperature is not taken into account in the design, hence the interest in proposing laws of dependence of the complex moduli is taken into account in the maximum temperatures of the pavement surface. The objective of this paper is to propose an experimental method to determine the temperature dependence of the complex moduli of asphalt mixes for temperatures between 40˚C and 70˚C. This experimental method consists of performing axial compression tests on cylindrical asphalt specimens. It was applied to three different formulas of bituminous mixes, intended for the wearing course, obtained from mixes of crushed granites, granular classes 6/10, 4/6 and 0/4, pure bitumens of grade 50/70, 35/50 and modified bitumen of grade 10/65. The comparative study of the experimental results obtained with the results of a semi-empirical methodology revealed a root mean square deviation from the mean of between 6.58% and 14.8% of the norms of the complex moduli (modulus of rigidity) of the asphalt mixes for a fixed frequency of solicitations of 10 Hz. The consistency of these results with data from the literature led to the initial conclusion that asphalt mixes formulated with 35/50 and 10/65 bitumen would have better compressive strength than those formulated with 50/70 bitumen, for exposure temperatures between 40˚C and 70˚C. This experimental approach could be an alternative to the complex modulus test for determining the modulus of rigidity for design purposes under real pavement exposure conditions in the city of Ouagadougou during heat waves.

关键词： Asphalt Mix Complex Modulus Axial Compression Semi-Empirical Methodology

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Comparative Study of the Thermal and Mechanical Properties of Foamed Concrete with Local Materials

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World Journal of Engineering and Technology 2022年第3期10卷 550-564页

作者： Adelaïde Lareba Ouédraogo Sayouba Kabré Etienne Malbila Abdoulaye Compaoré Ramatou Saré Paul Ilboudo Sié Kam Bruno Korgo Dieudonné Joseph Bathiebo Florent P. Kieno Philippe Blanchard Département de physique Laboratoire d’Energies Thermiques Renouvelables (LETRE) Faculté des Sciences Exactes et Appliquées (UFR/SEA) Ecole Doctorale Sciences et Technologies Université Joseph KI-ZERBO Ouagadougou Burkina Faso Département de physique Laboratoire des Matériaux et Environnement (LAME) Faculté des Sciences Exactes et Appliquées (UFR/SEA) Ecole Doctorale Sciences et Technologies Université de Ouagadougou Joseph KI-ZERBO Ouagadougou Burkina Faso Département de physique Université de Fada N’Gourma Fada Burkina Faso Département de physique Chimie Institut de Recherche sur les Céramiques (IRCER) Limoge France

Living in a habitat with comfort is requested by all. Cinder block bricks have poor thermal properties, leading people to use fan heaters and air conditioners to regain comfort. To overcome this problem of thermal discomfort in buildings, we used lightweight concrete such as foamed concrete which is a material that has improved thermal properties for thermal comfort. In addition, this material was compared with local materials used for the construction of buildings such as BTC, adobe and BLT mixed with binders. The results showed that foamed concrete is a material that has good thermal and mechanical properties compared to local materials mixed with binders. The foamed concrete having acceptable thermo-mechanical properties was that having a density of 930 kg/m3. It has a thermal resistance of 0.4 m2·K/W for a thickness of 20 cm. The foamed concrete having acceptable thermo-mechanical properties was that having a density of 930 kg/m3. It has a thermal resistance of 0.4 m2·K/W for a thickness of 20 cm. For sunshine on a daily cycle equal to 12 hours, the characteristic thickness achieved by this material is 7.29 cm. It also has a shallow depth of heat diffusion having a lower thickness than other materials. This shows that foamed concrete is a promising material for the construction of buildings.

关键词： Foamed Concrete Thermo-Mechanical Properties Comparison Local Materi-als

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Optimization of 6,13Bis(triisopropylsilylethynyl)pentacene (TIPS-Pentacene) Organic Field Effect Transistor: Annealing Temperature and Solvent Effects

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Materials Sciences and Applications 2018年第11期9卷 900-912页

作者： Diallo Abdoul Kadri Diallo Abdou Karim Mané Seck Kobor Diouma Pasquinelli Marcel Laboratoire de Chimie et de physique des Matériaux (LCPM) Assane Seck University Ziguinchor Senegal Gaston Berger University Department of Applied Physics Saint Louis Senegal OPTO-PV Group/institut Matériaux Microélectronique Nanosciences de Provence (IM2NP) Marseille France

In this contribution, we report on the effect of solvents with different boiling points and annealing temperature on the performance of TIPS-pentacene transistors. Several solvents have been used for TIPS-pentacene thin film processing: toluene, chlorobenzene and tetrahy-drofuran. To study the influence of solvent and temperature;the electrical parameters of TIPS-pentacene field effect transistor were measured. The highest values of mobilities were 7.1 × 10-3 cm2·V-1·s-1, 4.5 × 10-3?cm2·V-1·s-1 and 1.43 × 10-3 cm2·V-1·s-1 respectively for TIPS-pentacene field effect transistor using chlorobenzene, toluene and tetrahydrofuran and annealed respectively at 120°C, 150°C and 120°C. We have correlated these electrical performances with AFM images in order to point out the role of morphological properties. It is found that the grain size, and roughness highly affect the electrical parameters.

关键词： Tips-Pentacene Transistor Solvent Annealing Temperature

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Reconstruction Method in <i>F(G)</i>Gravity: Stability Study and Inflationary Survey

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Journal of Modern Physics 2021年第6期12卷 781-797页

作者： C. Aï namon M. J. S. Houndjo A. A. L. Ayivi M. G. Ganiou A. Kanfon institut de Mathématiques et de Sciences physiques (IMSP) Porto-Novo Bénin Faculté des Sciences et Techniques de Natitingou Natitingou Bénin Département de physique Université d’Abomey-Calavi Calavi Bénin

The present paper is devoted to reconstruction and cosmological study in modified F(G) theory of gravity. Our reconstruction scheme is based on Friedmann metric induced equations in modified F(G) theory by supposing a power law form for the scale factor of Friedmann metric. Firstly, we deal with the stability study, the obtained model. This survey reveals that for appropriated choice of the reconstructed model parameter, this model is stable under two cosmological evolutions namely the de Sitter and the power law evolutions symbolized by the appropriated scale factor. Secondly, we investigate the inflationary survey by fitting the model with the inflation observables. These observables are determined and their comparison with Planck’s results leads to a special inflationary F(G) model. We prove that this model especially obtained for radiation domination evolution develops an instability, so can fall to ordinary matter domination era or dark energy domination era. This is the key of graceful exit from inflation.

关键词： Modified Gravity Inflation Stability Gauss-Bonnet

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Cr-Doped TiO_(2)Thin Films Prepared by Means of a Magnetron Co-Sputtering Process:Photocatalytic Application

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American Journal of Analytical Chemistry 2014年第8期5卷 473-482页

作者： Anouar Hajjaji Atef Atyaoui Khaled Trabelsi Mosbah Amlouk Latifa Bousselmi Brahim Bessais My Ali El Khakani Mounir Gaidi institut National de la Recherche Scientifique INRS-EnergieMatériaux et TélécommunicationsVarennesCanada Laboratoire de Photovoltaique Centre de Recherches et des Technologies de l’EnergieTechnopole de Borj-CédriaHammam-LifTunisia Laboratoire de Traitement et de Recyclage des Eaux Centre de Recherches et des Technologies des EauxTechnopole de Borj-CedriaHammam-LifTunisia Unitéde physique des DispositifsàSemi-Conducteurs Facultédes Sciences de TunisCampus UniversitaireTunisTunisia department of Applied Physics University of SharjahSharjahUAE

This paper deals with the effect of Cr content on photocatalytic activity of TiO2 thin films deposited on quartz and intrinsic silicon substrates by using the RF magnetron co-sputtering process. Some physical investigations on such sputtered films were made by means of X-ray Diffraction (XRD), atomic force microscopy (AFM), Raman spectroscopy as well as UV-Vis-IR absorption techniques. The heat treatment under oxygen atmosphere at 550°C reveals that the crystalline structure of TiO2: Cr depends on Cr content. Anatase-to-rutile phase transformation occurs at a Cr content of about 7%. On the other hand, the band gap energy value of annealed TiO2: Cr films varies in terms of Cr doping and a transition around 7% of Cr is accrued. The photocatalytic activity of undoped and doped TiO2 films was evaluated by photo-degrading of the amido black under UV light irradiation. Modification of the chemical structure of titanium dioxide by Cr doping allows moving the photocatalytic activity of titanium dioxide towards visible light. The results indicate that films doped with 2% Cr exhibit the highest UV and visible light photocatalytic activity.

关键词： TiO_(2) Cr-Doped TiO_(2) Photocatalysis Opto-Electronic

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Low-strain TiP_(2)O_(7) withthree-dimensionalionchannelsas long-life and high-rate anode material for Mg-ion batteries

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Interdisciplinary Materials 2022年第1期1卷 140-147页

作者： Fangyu Xiong Yalong Jiang Li Cheng Ruohan Yu Shuangshuang Tan Chen Tang Chunli Zuo Qinyou An Yunlong Zhao Jean-Jacques Gaumet Liqiang Mai State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhanChina Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory FoshanChina Advanced Technology institute University of SurreyGuildfordSurreyUK Laboratoire de Chimie et physique:Approche Multi-echelles des Milieux Complexes Institut Jean BarriolUniversitede LorraineMetzFrance

Rechargeable magnesium batteries are identified as a promising next-generation energy storage system,but their development is hindered by the anode−electrolyte−cathode incompatibilities and passivation of magnesium metal *** avoid or alleviate these problems,the exploitation of alternative anode materials is a promising ***,we present titanium pyrophosphate(TiP_(2)O_(7))as anode materials for magnesium-ion batteries(MIBs)and investigate the effect of the crystal phase on its magnesium storage *** with the me-tastable layered TiP_(2)O_(7),the thermodynamically stable cubic TiP_(2)O_(7) displays a better rate capability of 72 mAh g^(−1) at 5000 mA g^(−1).Moreover,cubic TiP_(2)O_(7) exhibits excellent cycling stability with the capacity of 60 mAh g^(−1) after 5000 cycles at 1000 mA g^(−1),which are better than pre-viously reported Ti-based anode materials for *** situ X-ray diffraction technology confirms the single-phase magnesiumion inter-calation/deintercalation reaction mechanism of cubic TiP_(2)O_(7) with a low volume change of 3.2%.In addition,the density functional theory calcu-lation results demonstrate that three-dimensional magnesiumion diffu-sion can be allowed in cubic TiP_(2)O_(7) with a low migration energy barrier of 0.62 *** work demonstrates the promise of TiP_(2)O_(7) as high-rate and long-life anode materials for MIBs and may pave the way for further development of MIBs.

关键词： anode material intercalation low-strain Mg-ion battery TiP_(2)O_(7)

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Biochemical Methane Potential of Food Wastes from Akouedo Landfill, Côte d’Ivoire

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Green and Sustainable Chemistry 2018年第3期8卷 288-293页

作者： Kouadio Marc Cyril Kouakou Adjoumani Rodrigue Kra Essi Trokourey Albert Akichi Agboue Laboratoire de Chimie physique Université Félix Houphou&euml t Boigny Abidjan C&ocirc te d’Ivoire Laboratoire de mécanique et des sciences des matériaux Institut National Polytechniques Felix Houphou&euml t Boigny (INPHB) Yamoussoukro C&ocirc te d’Ivoire

The determination of biochemical methane potential (BMP) is very important for the valorization of food wastes. This study is focused on the evaluation of the theoretical methane production from chemical oxygen demand (COD) of some food wastes, coming out Akouedo landfill. Almost all of the considered samples exhibited methane theoretical yields equal to about 402.5 - 507.8 mLCH4/gVS. These results indicate the suitability of all the studied food wastes from Akouedo landfill to be converted into energy.

关键词： Biochemical Methane Potential Food Wastes Akouedo Landfill Chemical Oxygen demand

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