bluuebunny/crossref_metadata_2025 huggingface dataset:
The Seismic Response Analysis of Isolation Structure with Shape Memory Alloy Re-Centring Dampers
Authors: Miao Xiao Yu , Wang She Liang , Fan Yu Jiang
Published: September 2011

Shape memory alloy (SMA) is provided with preferable damp capacity at pseudo-elasticity state, applying this property, a SMA re-centring damper is introduced by some scholars. In this paper, the new isolation system combining the above damper with laminated rubber bearing is proposed, so as to obtain preferable isolation character and re-centring capacity. To illustrate the feasibility and effectiveness of the proposed system, the following work is done: First, according the constitution model of SMA at pseudo-elasticity state the program is compiled, then the mechanical behavior of damper is simulated and the hysteretic curve is obtained. Based on the above, a linear restoring model for SMA re-centring damper is put forward. And then, the program based on the theory of story model for shear tape is compiled to conduct elasto-plastic time history analysis of practical structure examples, According to the results, the seismic response of structure is significantly reduced, and the fully re-centring capacity after earthquake is obtained by this isolation system.
Preparation and Properties of PS-OMMT/SBS Composite Modified Asphalt
Authors: Zhou De Jie , Han Nian Feng , Tang Xin De
Published: September 2011

The polystyrene modified organophilic montmorillonite clays (PS-OMMT) were preparation through intercalating styrene monomer into the layer of OMMT by in-situ polymerization. Composite modified asphalts with PS-OMMT and SBS were prepared by melt blending. Results showed the interlayer spacing of OMMT was increased by the intercalated polymerization reaction of styrene. The modified OMMT and SBS homogeneously disperse in the base asphalt, which lead to an improvement in terms of toughness, strength, and thermal stability. Impact of the PS-OMMT on the properties of SBS modified asphalt appears as a decreasing penetration, an increasing softening point, and a decreasing ductility. Compared with that of SBS modified asphalt, the anti-aging property of PS-OMMT /SBS modified asphalt was greatly improved.
A Study on the Influencing Factors on the Dry-Shrinkage Performance of Phosphate Cement
Authors: Tang Chun Ping
Published: September 2011

Aiming at the characteristics of phosphate repairing materials, the influences of retarder, specific surface area of magnesium oxide and content of fly ash on the dry-shrinkage performance of phosphate cement were studied in this paper. The results showed that greater content of retarder would result in greater dry-shrinkage value within a certain range, greater specific area of magnesium oxide would result in greater dry-shrinkage value while the increase of content of fly ash would cause the dry-shrinkage value to be decreased correspondingly within a certain range.
Electronic Market Credit Risk Evaluation for Agricultural Products Based on Analytic Hierarchy Process
Authors: Li You Zhu , He De Hua
Published: September 2011

In the study, electronic market credit risk evaluation for agricultural products based on analytic hierarchy process is proposed.Firstly, the evaluation indexes are analyzed and the hierarchic tree is formulated based on the evaluation indexes.Then, pairwise comparison matrix is established,and the consistency of discriminant matrix is judged.When the consistency of discriminant matrix is satisfied,the weight vector of the indexes which are used to establish the pairwise comparison matrix are obtained. And weight of each index is obtained.Finally,final decision making is obtained. The experimental results show that the evaluation of electronic market credit risk evaluation for agricultural products based on analytic hierarchy process is effective.
Experimental Research on Osmotic Coefficient of Gangue Concrete
Authors: Guo Jin Min , Song Shuai Qi , Zhu Ling Li
Published: September 2011

Permeability of concrete was an important part of durability. Osmotic coefficient of gangue concrete was studied by orthogonal test. The test analyzed the influence of coal gangue, fly ash and slag in place of aggregate and cement on osmotic coefficient of concrete. The results showed that compression strength was highest and osmotic coefficient was lowest when gangue was in place of 30% aggregate, fly ash was instead of 20% cement, slag took the place of 20% cement. And gangue in place of some aggregate had biggest influence on the osmotic coefficient in coal gangue concrete. At the same time, its mechanical properties and permeability were controlled in a good condition. Finally, the results could provide useful technical reference to exploit the green building material from gangue.
Method for Determining Deep Ground Thermal Properties Based on Solid Cylindrical heat Source Model
Authors: Yu Ming Zhi , Yu Xiao Fei , Zhang Lei , Fang Zhao Hong
Published: September 2011

A method is proposed to determine deep ground thermal properties at worksites using one-dimensional ground heat exchanger solid cylindrical heat source model together with parameters estimation method. The ground thermal properties of an actual project were measured and analyzed by this method, and the results show that this method can get credible ground thermal properties, which can be used for engineering design.
Ø100mm SHPB Equipment and its Application
Authors: Zhang Zhi Gang , Li Meng Shen , Wang Xiao Long , Zhong Xiao Lei , Li Qing
Published: September 2011

Hopkinson Pressure Bar (HPB) is one of the main sets to study material dynamic mechanic properties. Large diameter HPB is mainly used for nonhomogeneous materials. In this paper the properties of Split Hopkinson Pressure Bar (SHPB) of Ø100mm are introduced, including its structure and performance index. The main problems of large diameter SHPB are analyzed. The further development and application of SHPB are also explored.
Application of Automatic Assembly Technology Based on BRep on Inventor
Authors: Yin Wei Bo , Wei Lu Shuang , Wei Qun
Published: September 2011

A new method of automatic assembly technology (AAT )is proposed on 3D design platform, which marks the primitives by BRep and save the data into the Xdata by BRep, then gets the elements by indexing the Xdata and assemblies them through assembly relationships in assembly, which is adopt in secondary development of Autodesk Inventor with better effort.
Study on Large Wind Power Tower Structure Concept Optimization
Authors: Shao Lian Fen , Zheng Rui Jie
Published: September 2011

This paper establishes the prestressed wind power tower model and studies on large wind power tower structure concept optimization for wind power development trends and problems. The results show that, no matter how weight of steel tower, or the amount of base concrete earthwork, the prestressed wind power tower has the potential to reduce the construction cost with good prospects. And the conclusions can provide a useful reference for the wind power constructions.
Reinforcement Mechanism of Cement/Lime-Fly Ash Treated Sediments as Road Construction Materials
Authors: Wang Dong Xing , Wang Hong Xing , Chen Wen Zhao
Published: September 2011

Solidified dredged materials as environment-friendly materials in construction domain are increasingly popular because of their better mechanical performance and low pollution. Based on the physical characteristic of dredged marine sediments, a series of tests, such as unconfined compressive strength test and tensile strength test, were performed to explore the mechanical properties of cement/lime-fly ash treated sediments for the beneficial use in road construction. Finally, the reinforcement mechanism of solidified sediments was explored by SEM tests from the point of view of the formation of CSH phases and the change in microstructure.
Study on the Method of Making Road-Base-Map of Traffic Accident Scene
Authors: Chen Su Zhen , Yao Lian Bi , Wu Hang Bin , Ji Hui Li , Men Mao Lin
Published: September 2011

There are two elements in road traffic accident scene graph, base map and other elements in the site of traffic accident. The base map mainly includes traffic sings and traffic markings. Drawing traffic accident scene graph is a necessary link during disposing road traffic accident, while drawing the base map costs most of the time of drawing traffic accident scene. In order to save processing time of dealing with the traffic accident, the concept of road base map is proposed. The symbol design and data organization of the base map are analyzed. All this provides a new way to make the traffic accident scene graph.
Factors Affecting the Compressive Strength of Class C Fly Ash Geopolymer
Authors: Li Xue Ying , Zheng En Zu , Ma Chun Long
Published: September 2011

The compressive strength of geopolymer prepared from a class C fly ash (CFA) at different curing conditions and mass ratio of water to fly ash were investigated. The geopolymer was activated with a mixed solution of sodium hydroxide (NaOH) and sodium silicate. The results revealed that the obtained compressive strength was in the range of 11.7~61.9MPa and the compressive strength decreased with the increment of the mass ratio of water to CFA (W/F). The geopolymer samples with the highest strength were obtained when W/F was 0.30 with proper delay time 1d before being demoulded and then followed by curing at 60°C for 24h. For geopolymer with lower W/F (0.30), its optimum curing temperature was better not higher than 60°C, however, for the higher W/F, the curing temperature was suit to more than 70°C.
Performance Research of Strain Hardening Cementitious Composites (SHCC) under Uniaxial Tensile Load
Authors: Hu Chun Hong , Zhao Tie Jun , Rong Tao
Published: September 2011

Strain Hardening Cementitious Composites (SHCC) varied with mixture proportion was preparated with normal engineering materials in our area, tensile performance of dumbbell specimens under uniaxial tensile load was experimentally investigated in this paper, and tensile stress versus strain curves as well as crack development of SHCC with different mixture proportion were obtained. The results showed that all specimens had strain-hardening and multiple-cracking characteristics obviously, among them, ultimate tensile strain of No.A and C series could exceed 3%. SHCC with excellent stable tensile performance was preparated based on normal river sand but not quartz sand, which can reduce project cost and promote the application and development of SHCC in practical engineering.
Effect of Deposition Time on Physical Properties of Nanocrystallized SnS Zinc Blend Thin Films Grown by Chemical Bath Deposition
Authors: Akkari Anis , Regima Meriem , Guasch Cathy , Kamoun Turki Najoua
Published: September 2011

Abstract. Zinc blend tin sulphide thin films have been successfully prepared on Pyrex substrates using low cost chemical bath depositiontechnique. In this work, we study the effect of time deposition on the physical properties of SnS thin film. A 200 nm thick layer is obtained as an optimum value for deposition time td equal to four hours. X-Ray diffraction study shows that SnS exhibits a zinc blend structure with preferential orientations (111)ZB and (200)ZB. Optical analyses by means of transmission T(λ) and reflection R(λ) measurements allow to determine the direct band gap energy value ≈1.7 eV. Thin layers of tin sulphide exhibit a high absorption coefficient up to 1.5×106 cm-1 in the visible domain, indicating that SnS compound has absorbing properties favorable for applications in solar cell devices.
Influence of Experimental Parameters on the Synthesis of Gold Nanoparticles by Electroless Deposition
Authors: Bechelany Mikhael , Elias Jamil , Hankache Jihane , Brodard Pierre , Philippe Laetitia , Michler Johann
Published: September 2011

We report a simple synthetic route based on electroless deposition (galvanic displacement) and natural lithography to synthesize organized Au nanoparticles (NPs). We will study the influence of different experimental parameters (time, temperature, pH and additives) on the synthetic process. We show for the first time the formation of organized extended domains of Au nanorings using gelatin as an additive. A wide range of applications can be envisaged for these nanostructures, as for instance chemical- and bio-sensors using the SERS effect.
Effect of Surface Structure on Heteroepitaxial Growth of Silver Nanoparticles on WO3 Thin Films
Authors: Al Mohammad Ahmad , Alsous Mohamad B.
Published: September 2011

The effect of surface structures of annealed WO3 thin films on heteroepitaxial growth of molecular beam epitaxy (MBE) deposited silver nanoparticles (Ag NPs) has been investigated. Hexagonal WO3 (h-WO3) and monoclinic WO3 (m-WO3) thin films were used in (1x1) stoichiometric forms. The structure, the density, the particle size and the morphology of Ag NPs on WO3 films were determined by transmission electron microscope (TEM) and selected area electron diffraction (SAEC). Ag NPs on the m-WO3 surface created the (111)Ag//(001)m-WO3 interface without preferred orientations while the epitaxial relationships between Ag NPs and the h-WO3 films were formed as (111)Ag//(0001)h-WO3 and Ag[01-1]//[21-30]h-WO3. It was observed that the particle density, the mean size and the size dispersion of Ag NPs were controlled by either atom diffusion or by particle migration on the substrates. The maximum cluster density method and the Lifethenz theory of Van der Waals energy were used to investigate the Ag NP morphology and Ag//WO3 interface parameters at saturation particle density of NPs.
Investigation of the Formation Mechanisms of Pd Nanoclusters Produced Using a Magnetron Sputtering Source
Authors: Ayesh Ahmad I. , Thaker Saleh , Qamhieh Naser , Ghamlouche Hassan
Published: September 2011

We report on the fabrication of palladium (Pd) nanoclusters using a dc magnetron sputtering source. The sputtering source produces ionized nanoclusters that enable the study of the nanoclusters’ size distribution using a quadrupole mass filter. In this work, the dependence of Pd nanoclusters’ size distribution on various source parameters, such as the inert gas flow rate, and aggregation length have been investigated in details. This work demonstrates the ability of tuning the palladium nanoclusters’ size by proper optimization of the source operation conditions.
Effect of Oxygen and Water in the CO Photocatalytic Oxidation with TiO2
Authors: Youssef Carlos , Puzenat Eric , Najm Samir , Jaffrezic-Renault Nicole , Guillard Chantal
Published: September 2011

TiO2 P25 catalyst was used to study the photocatalytic oxidation of CO to CO2 at 288K. Two parameters, O2 and H2O were used to study its effect on the photocatalytic process. The dependency of the reaction rate on the CO concentration and water vapor was explained in terms of Langmuir-Hinshelwood mechanism. The presence of a high concentration of water vapor inhibits the CO photocatalytic oxidation at low oxygen concentration. We have noted an adsorption competition between CO and H2O on the TiO2 active sites.
The Performance of the Cu-Zn/CeO2 Catalysts in the Steam Reforming of Methanol Reaction
Authors: Mrad Mary , Gennequin Cédric , Aboukaïs Antoine , Abi-Aad Edmond
Published: September 2011

The performances of different xCu10Ce and xZn10Ce (x = 1, 3, and 5) catalysts prepared by impregnation method then pelletised, were investigated in the steam reforming of methanol (SRM) under a GHSV = 15500 h-1 with H2O/CH3OH = 2. The impregnation of copper over ceria supports shows better results than that of zinc. The catalytic activity in the Cu-based depends on the dispersion of the copper species. The methanol conversion rate is related to the formation of an optimum content of reduced copper species.
Influence of Shaping on Pd and Pt/TiO2 Catalysts in Total Oxidation of VOCs
Authors: Barakat Tarek , Finne Gauthier , Franco Manuel , Cousin Renaud , Giraudon Jean Marc , Lamonier Jean François , Thomas Diane , Decroly André , Deweireld Guy , Siffert Stéphane
Published: September 2011

The catalytic performance of a commercial TiO2 was investigated towards the total oxidation of toluene. A variety of two titania supports was used in this work, shaped (pellets) and non-shaped (powder) materials. 0.5wt% Pd or Pt were impregnated onto both types of titania supports using the wet impregnation method. A decrease in the surface area of the obtained catalysts was noticed after the catalytic test, although it was still much higher than that of classical titania supports. The catalysts were tested in the total oxidation of toluene, and a major decrease in activity was noticed for Pt impregnated “shaped” supports.
Kinetics of Ion-Pair Effect of Aquation of Bromopentaammine Cobalt(III) Complex in Different Dicarboxylate Media
Authors: Zeitouni Farah , El-Subruiti Gehan , Younes Ghassan , Amira Mohammad
Published: September 2011

The rate of aquation of bromopentaammine cobalt(III) ion in the presence of different types of dicarboxylate solutions containing tert-butanol (40% V/V) have been measured spectrophotometrically at different temperatures (30-600°C) in the light of the effects of ion-pairing on reaction rates and mechanism. The thermodynamic and extrathermodynamic parameters of activation have been calculated and discussed in terms of solvent effect on the ion-pair aquation reaction. The free energy of activation ∆Gip* is more or less linearly varied among the studied dicarboxylate ion-pairing ligands indicating the presence of compensation effect between ∆Hip* and ∆Sip*. Comparing the kip values with respect of different buffers at 40% of ter-butanol is introduced.
Spectrophotometric Study of Cobalt (II) Chlorocomplexes in Methanol in the Visible Domain
Authors: Boulefred Soumia , Chiboub Fellah Abdelghani , Chiboub-Fellah Fatema Zohra , Khan Mustayeen Ahmed
Published: September 2011

Cobalt(II) chlorocomplexes were studied in a polar protic solvent namely methanol at 25°C. The spectrophotometric technique in the visible region was used. The studied equilibrium is: Co2+ + j Cl- CoClj ↔ (j-2)-. Formation of three chlorocomplexes and a structural modification (Oh → Td) were obtained from recorded spectra analysis. The stability of CoCl+ was studied by the graphical method of Kruh and the overall stability constants were calculated with the SIRKO program based on the least-square method. Different models were tested and the model was retained for which the best values are: log β1 = 0.92, log β2 = 1.31 and log β3 = 1.08.
Mechanical Study of Copper Bonded at Low Temperature Using Spark Plasma Sintering Process
Authors: Mouawad Bassem , Soueidan Maher , Fabrègue Damien , Buttay Cyril , Bley Vincent , Allard Bruno
Published: September 2011

Bonding of high purity polished copper was investigated using the Spark Plasma Sintering technique (SPS) showing the effect of SPS parameters (surface roughness, time, temperature and pressure) on the bonding strength behaviour. Mechanical characterization of the bonded samples was performed at room temperature using tensile test. Two surfaces roughnesses were studied (un-polished and polished samples). It was found that the bonding strength varied from 50 MPa to 233 MPa for un-polished and polished surfaces respectively The tensile strength of the used bulk copper-rod was found to be 365 MPa, while most results are over 122 MPa (a third of the bulk value).
Evaluation of Longitudinal and Transversal Young’s Moduli for Unidirectional Composite Material with Long Fibers
Authors: Hallal Ali , Fardoun Farouk , Younes Rafic , Hage Chehade Fadi
Published: September 2011

This work represents a comparative study of available analytical micromechanical models used to evaluate the elastic properties of unidirectional (UD) composite material with long fibers (where the ratio Length/Diameter of the fibers is considered to be infinite). The objective of this work is to find the appropriate model, to be used with different volume fractions of fibers, to determine the micromechanical elastic properties. This study is carried out due to the importance of using the suitable micromechanical model, when modeling bi-dimensional and tridimensional composite materials. The models are divided into two different categories: rheological, and inclusion models. The UD composite material represents a transversely isotropic material composed of two phases: the reinforcement phase and the matrix phase. Isotropic fibers (e.g. glass fibers) or anisotropic fibers (e.g. carbon fibers) represent the reinforcement phase while an isotropic material (e.g. epoxy) represents the matrix phase. In this study only longitudinal and transversal Young’s moduli are discussed. Analytical and Finite element modeling is made for a carbon fiber/epoxy UD composite. The obtained analytical results are compared to those obtained numerically and to the available experimental data. The analytical results are evaluated for different values of fiber volume fraction Vf ranging from 0 to 1.
Modeling Shock Induced Plasticity in Copper Single Crystal: Numerical and Strain Localization Issues
Authors: Shehahdeh Mutasem
Published: September 2011

Multiscale dislocation dynamics plasticity (MDDP) simulations are carried out to address the following issues in modeling shock-induced plasticity: 1- the effect of finite element (FE) boundary conditions on shock wave characteristics and wave-dislocation interaction, 2- the effect of the evolution of the dislocation microstructure on lattice rotation and strain localization. While uniaxial strain is achieved with high accuracy using confined boundary condition, periodic boundary condition yields a disturbed wave profile due the edge effect. Including lattice rotation in the analysis leads to higher dislocation density and more localized plastic strain.
The Crystal Structure of Dibromonitrotoluen (DBNT) C7Br2H5 NO2
Authors: Medjroubi Mohamed Larbi , Brihi Ouarda , Hamdouni Noudjoud , Boudjada Ali , Meinnel Jean
Published: September 2011

The crystal structure of Dibromonitrotoluen (DBNT) obtained at the ambient temperature 293k from the X-ray diffraction crystallizes in the space group P-1 with 2 molecules by mesh. The crystal growth is made along the a axis. In parallel with this study, a theoretical calculation of molecular conformation from the density functional theory (DFT) carried out using the Gaussian03 chain program in the case of isolated molecule, led to results of Optimization very close to the experiment. The molecular conformation calculations were made from two different functional the B3LYP and MPW1PW91. The values of bond lengths obtained from the functional MPW1PW91 and base set 6-311G are very close to the experiment with a gap of 1.25% (2.14% for the B3LYP) while for bond angles, calculation results are better for functional B3LYP (Lan2DZ) 0.95% and 1.02% for MPW1PW91.In this work a study of internal modes of Dibromonitrotoluen (DBNT) is presented, while comparing the infrared spectroscopic experimental results and the DFT studies of the isolated molecule. This material is a good probe to test the model precision and the calculated methods used to interpret dynamic properties by experimental spectroscopy.
Investigation of Thermo-Oxidative Polyimide Thin Film Aging at High Temperature
Authors: Khazaka Rabih , Locatelli Marie Laure , Diaham Sombel , Schlegel Benoit
Published: September 2011

Polyimides (PIs) are widely used in electronics wherein high temperature (HT) insulating layers are needed. Like other polymers used in HT and in ambient atmosphere, polyimides are subject to the thermal and thermo-oxidative degradations. The thermo-oxidative aging can lead to the material dielectric properties degradation and then to the device failure. Therefore, it is important to study the thermo-oxidative aging effect on the dielectric properties of PI thin films, in order to predict their lifetime. During the thermo-oxidative aging of PI films deposited on stainless steel substrate at 300 °C in air, electrical (dielectric loss, DC conductivity, breakdown voltage), physical (thickness and surface profile) and physicochemical (FTIR) properties, have been monitored for different film thicknesses. Results are analyzed and discussed in order to choose the suitable life end point criterion, and to estimate the mean time to reach it in such aging conditions.
Nonlinear Electrodynamic and Optical Properties of Graphene
Authors: Mikhailov Sergey A.
Published: September 2011

Graphene is a recently discovered new material with unique physical properties. In this paper we discuss its electrodynamic and optical properties. It is shown that the electromagnetic response of graphene to the external radiation is strongly nonlinear and such phenomena as the frequency harmonics generation and frequency mixing effects can be observed in it. The nonlinear susceptibility of graphene is higher than that of many other materials.We predict that under certain conditions the plasmon enhanced second harmonic generation can be observed in graphene.
Electrical and Optical Properties of Indium-Modified SeSbTe Thin Films for Low Power Memory Devices
Authors: Ghamlouche Hassan , Mahmoud Saleh Thaker , Qamhieh Naser , Ayesh Ahmad I.
Published: September 2011

The electrical and optical characteristics of indium doped Se2Sb2Te6 phase-change alloy are studied. It is found that adding indium to Se2Sb2Te6 alloy (In0.3Se2Sb2Te6) increased the crystallization temperature and reduced the electrical conduction activation energy. The capacitance-temperature measurements showed a drastic change in the capacitance of the modified film when the temperature approaches the crystallization temperature, and eventually the capacitance becomes negative and nonlinear. The negativity and nonlinearity in the capacitancevoltage dependence can be attributed to the growth of conductive crystalline islands by increasing the temperature.
Structural, Optical and Electrical Properties of ZnO Sprayed Thin Films Doped with Fluorine
Authors: Douayar A. , Diaz Raquel , Prieto P. , Abd-Lefdil Mohammed
Published: September 2011

F-doped ZnO films (FZO) of about 400 nm thicknesses were prepared on glass substrates by the chemical spray pyrolysis technique. X-ray diffraction patterns showed that the undoped and F-doped ZnO films exhibit the hexagonal wurtzite crystal structure with a preferential orientation along [002] direction. No secondary phase is observed in F-doped ZnO films. All films exhibit a transmittance around 80% in the visible range. Photoluminescence spectra at room temperature of undoped and F doped ZnO thin films are presented. The wide PL bands centered at 510 and 680 nm are characteristic of deep levels of oxygen vacancies in the ZnO matrix, and zinc interstitial position. The FZO films are degenerate and exhibit n-type electrical conductivity. The lowest electrical resistivity was 7.6 10−3 Ω cm.
Segregation and Clustering Effects on Complex Boron Redistribution in Strongly Doped Polycrystalline-Silicon Layers
Authors: Abadli Salah , Mansour Farida
Published: September 2011

This work deals with the investigation of the complex phenomenon of boron (B) transient enhanced diffusion (TED) in strongly implanted silicon (Si) layers. It concerns the instantaneous influences of the strong B concentrations, the Si layers crystallization, the clustering and the B trapping/segregation during thermal post-implantation annealing. We have used Si thin layers obtained from disilane (Si2H6) by low pressure chemical vapor deposition (LPCVD) and then B implanted with a dose of 4×1015 atoms/cm2 at an energy of 15 keV. To avoid long redistributions, thermal annealing was carried out at relatively low-temperatures (700, 750 and 800 °C) for various short-times ranging between 1 and 30 minutes. To investigate the experimental secondary ion mass spectroscopy (SIMS) doping profiles, a redistribution model well adapted to the particular structure of Si-LPCVD layers and to the effects of strong-concentrations has been established. The good adjustment of the simulated profiles with the experimental SIMS profiles allowed a fundamental understanding about the instantaneous physical phenomena giving and disturbing the TED process in strongly doped Si-LPCVD layers. It was found that boron TED is strongly affected by the simultaneous complex kinetics of clustering, crystallization, trapping and segregation during annealing. The fast formation of small Si–B clusters enhances the B diffusivity whereas the evolution of the clusters and segregation reduce this enhancement.
Implantation of Nitrogen Atoms in 4H-SiC Epitaxial Layers: A Comparison between Standard and Plasma Immersion Processes
Authors: Ottaviani Laurent , Biondo Stéphane , Kazan Michel , Palais Olivier , Duchaine Julian , Milesi Frédéric , Daineche Rachid , Courtois Blandine , Torregrosa Frank
Published: September 2011

This paper focuses on the formation of thin n+p junctions in p-type Silicon Carbide (SiC) epitaxial layers using two kinds of Nitrogen implantations. The standard beam ion implantations and PULSIONTM processes were performed at two distinct energies (700 eV and 7 keV), and the subsequent annealing was held at 1600°C in a resistive furnace specifically adapted to SiC material. No measurable electrical activity was obtained for both implantations performed at 700 eV, due to some outdiffusion of N dopants during the annealing despite a low surface roughness (rms ~ 1.4 nm) and no residual damage detected by RBS/C. A higher sheet resistance was measured in plasma-implanted samples at 7 keV (in comparison with beam-line implanted samples), which is partly related to N outdiffusion. The profiles of N atoms beam-implanted at 7 keV are not affected by the annealing. The corresponding electrical activation is fully completed.
Analytical Method to Calibrate Cylindrical LaBr3(Ce) Scintillation Detector
Authors: Abbas Mahmoud Ibrahim
Published: September 2011

A new analytical method of efficiency calibration is proposed for cylindrical lanthanum bromide (LaBr3:Ce) scintillation detectors. The cerium-doped lanthanum halide crystals have gained special interest due to their high density and atomic number, which results in excellent scintillation properties and higher detection efficiencies in comparison to NaI(Tl). The comparisons with the experimental and Monte Carlo method data reported in the literature indicate that the present method is useful in the efficiency calibration of the cylindrical lanthanum bromide scintillation detectors.
High Frequency Ultrasound, a Tool for Elastic Properties Measurement of Thin Films Fabricated on Silicon
Authors: Campistron Pierre , Carlier Julien , Saad Nadine , Gao Jamin , Toubal Malika , Dupont Lucie , Nassar Georges , Nongaillard Bertrand
Published: September 2011

The main goal of this work is to develop an ultrasonic high frequency method for characterization of thin layers. The development of high frequency acoustic transducers for longitudinal waves and shear waves on silicon has enabeled the characterization of thin films deposited on this substrate. Three types of transducers have been achieved : (i) single crystal LiNbOSubscript text3 Y+163° for shear waves generation, and (ii) Y+36° for longitudinal waves, bonded and thinned on silicon substrate to achieve ultrasonic transducers in the frequency range 300-600 MHz ; (iii) thin films ZnO transducers were realized due to sputtering technologies working in the frequency range 1 GHz- 2.5 GHz. Using an inversion method and a network analyser which provide the scattering S11 parameter of the transducer versus the frequency we deduce the elastic properties of films deposited on the wafer surface. Thanks to these transducers the acoustic properties of thin films such as SU-8 based nanocomposites (doped with TiO2 , SrTiO3 or W nanoparticles) will be presented. In order to achieve mechanical impedance matching between silicon and water we control the mass of the embedded particles which provide a way to adjust the elastic properties of the characterized material. In another application an Indium metallic layer have been characterized in the high frequency range. We also use this method to characterize dielectric permittivity of the ZnO transducers.
The Low-Lying Excited Electronic States of an Alkali-Earth Compounds
Authors: Korek Mahmoud , Razzouk Hadeel , Abou Arkoub Rasha , El Atwani Sara
Published: September 2011

Since there is lack in the excited electronic states of alkaline earth compound, candidate for ultracold investigation, and by using an ab initio calculation the potential energy curves have been obtained for the lowest electronic states in the 2s+1Λ(±) representation below 53000 cm-1 along with the harmonic frequency we, the internuclear distance re, the rotational constant Be, and the electronic energy with respect to the ground state Te. The comparison of these values to the theoretical and experimental results available in the literature shows a good agreement
Magnetic Behavior of Barium Hexaferrite Nanoparticles
Authors: Boyajian Taline , Vincent Didier , Le Berre Martine , Neveu Sophie
Published: September 2011

An analysis of the magnetic behavior of Barium Hexaferrite nanoparticles is presented in this paper. The particles’ average size is around 200 nm. The SU-8 photoresist is used as dielectric host matrix in which the particles are embedded. The volume fraction of magnetic particles reached is around 10%. Microwave characterizations show the properties of the resulting nanocomposite. The external applied magnetic field plays the main role in orienting these magnetic particles in the composite. Coplanar CPW lines were used to investigate the magnetic material’s efficiency by its non-reciprocal effects. Magnetic nanocomposites seem promising material for future applications. Thus, higher magnetic particle volume fractions and better orientation are required.
Determination of Initial Magnetic Permeability of YIG Thin Films Using the Current Sheet Method
Authors: Siblini Ali , Khalil Ismaïl , Chatelon Jean Pierre , Rousseau Jean Jacques
Published: September 2011

Abstract. A new technique of inductive measure to determine the initial magnetic permeability (r) of Yttrium Iron Garnet (YIG) thin films has been conceived and developed in our laboratory. The magnetic material is deposited by radio-frequency sputtering between two copper thin layers on alumina substrate. Because the as-deposited films are amorphous and non magnetic, thermal annealing is necessary to make the films crystallize and to obtain satisfactory magnetic properties. After different tests considering the geometrical, morphological and magnetic properties, we have established a protocol permitting to manufacture a prototype in an original design. The performance of the fabricated micro-inductor has been checked using a physical-chemistry characterization. To obtain accurate measurements, we have used a four-point probe test bench and a precision LCR meter. The current sheet method has been validated with thick layers of commercial YIG. The results obtained for thick and thin films of YIG have been compared to the simulation and theoretical ones. Several tests, made for different thickness and different number of loops, have permitted us to evaluate the magnetic permeability of YIG thin films to 32 ± 4.
Recent Developments in Nanoscience and Nanotechnology
Authors: Pépin Anne , Bernier Patrick , Lannoo Michel
Published: September 2011

This talk is intended to give an overview of research in Nanoscience and Nanotechnology (N&N) in France and especially at the French National Center for Scientific Research (CNRS), which has made research in N&N one of its five priorities. In the first part we list the main scientific issues at stake, as they were identified in a recent scientific workshop held at CNRS. In the second part we present the French organization of research in N&N and give comparative estimates of the funding in France, Europe, USA and Japan. We end up by summarizing some elements of CNRS strategy in the field.
On the Characterization of Ultra Thin Al Films Deposited onto SiC Substrate Using PIXE Technique
Authors: Younes Ghassan , Soueidan Maher , Ferro Gabriel , Zahraman Khaled , Nsouli Bilal
Published: September 2011

In this work the capability of the proton induced X-ray emission (PIXE) technique to monitor a rapid, non-destructive and accurate quantification of Al on or inside SiC is discussed. Optimization of PIXE acquisition parameters was performed using as reference, a thin Al film (2.5 nm) thermally evaporated onto silicon carbide substrate. In order to improve the sensitivity for Al detection and quantitative determination, a systematic study was undertaken using proton ion beam at different energies (from 0.2 to 3 MeV) with a different tilting angle (0°, 60°, and 80°). The limit of detection (LOD) was found to be lower than 0.02 nm. The optimum PIXE conditions (energy, angle) were applied for determining the Al doping concentration in thin (1 µm) 4H-SiC homoepitaxial layer. The Al concentration as determined by PIXE was found to be 3.9x1020 at/cm3 in good agreement with SIMS measurements, and the LOD was estimated to be 6x1018 at/cm3.
On the Characterization of Boron in BGaAs Nano-Films Using IBA Techniques
Authors: Abboudy Sayed , Soueidan Maher , Al Asaad Qassem , Auvray Laurent , Ferro Gabriel , Roumie Mohamad , Nsouli Bilal
Published: September 2011

In this work, the capability of the proton Induced γ-ray Emission (PIGE) technique to monitor a rapid, nondestructive and quantification of Boron in ultra-thin films of BxGa1-xAs deposited on GaAs substrate using MOCVD is discussed. In order to improve the sensitivity for B detection, a systematic study was undertaken using proton induced beam at three different energies (from 1.7, 2.4 and 3 MeV) with different tilting angles (0, 60° and 80°). Best conditions were found to be at 1.7 MeV and at 80° for proton energy and tilting angle within ten minutes of acquisition time.
LIBS for the Analysis of Metallurgical and Solar Grade Silicon
Authors: Darwiche Sarah , Benmansour Malek , Eliezer Nir , Morvan Daniel
Published: September 2011

Laser-induced breakdown spectroscopy (LIBS) has been employed for the fast and reliable chemical characterization of silicon used for the photovoltaic industry. Silicon for photovoltaic panels is subject to certain constraints on its purity, and notably must contain low concentration of boron. The use of LIBS could be advantageous because it allows rapid and simultaneous multi-elemental chemical analysis of silicon without any sample preparation. LIBS was applied to boron analysis and a detection limit of 0.23 ppmw was found for optimized gas and pressure conditions.
Analyses of under Pressure Polyacetylene Conductivity
Authors: Saidi Mohamed , Beldjilali Abdeselem , Saidi-Amroun Nadia
Published: September 2011

Electrical measurements under increasing hydrostatic pressure (1–4000 [bar]) have shown that electrical conductivity is closely related to the iodine doping rate (0–14%) of polyacetylene (PA) films. In pristine PA, conductivity increases with pressure while in 14% iodinedoped PA it decreases. A most important result is noticed for an intermediate doping rate (1.5%). In fact, for sweeping of the range of pressure, conductivity decreases in the beginning and then increases with pressure augmentation. This change is located at a critical pressure Pc. An empirical formula was proposed to describe this behaviour. The aim of this work is to contribute to the greater understanding of the pressure effect on the transport mechanism and/or the nature of charge carriers.
New Type of Lime Plaster with Pozzolana Admixture for Renewal of Historical Buildings
Authors: Pavlík Zbyšek , Pavlíková Milena , Maděra Jiří , Černý Robert
Published: September 2011

Lime plaster modified with pozzolana based on calcined kaoline mixed with mudstone and reference lime plaster are studied in the paper. For the studied materials, determination of bulk density, matrix density and total open porosity is done first. Then, specific attention is paid to the assessment of moisture diffusivity and chloride diffusion coefficient that are considered as decisive parameters for the materials’ durability. The measured data are used as input parameters for computational modeling of studied materials’ performance using computer code TRANSMAT 6.2 based on finite element computer simulation tool. On the basis of measured and calculated results, the applicability of newly developed plaster for renewal of historical buildings is discussed.
Durability of Self-Compacting Concrete
Authors: Benmarce Abdelaziz , Boudjehem Hocine , Bendjhaiche Robila
Published: September 2011

Abstract. Self compacting concrete (SCC) seem to be a very promising materials for construction thanks to their properties in a fresh state. Studying of the influence of the parameters of specific designed mixes to their mechanical, physical and chemical characteristics in a state hardened is an important stage so that it can be useful for new-to-the-field researchers and designers (worldwide) beginning studies and work involving self compacting concrete. The objective of this research is to study the durability of self compacting concrete. The durability of concrete depends very much on the porosity; the latter determines the intensity of interactions with aggressive agents. The pores inside of concrete facilitate the process of damage, which began generally on the surface. We are interested to measure the porosity of concrete on five SCC with different compositions (w/c, additives) and vibrated concrete to highlight the influence of the latter on the porosity, thereafter on the compressive strength and the transfer properties (oxygen permeability, chloride ion diffusion, capillary absorption).
Interaction Deep Excavation – Adjacent Structure: Numerical Two and Three Dimensional Modeling
Authors: Abdallah M. , Hage Chehade Fadi , Chehade Walid , Fawaz A.
Published: September 2011

Urban development often requires the construction of deep excavations near to buildings or other structures. We have to study complex material structure interactions where we should take into consideration several particularities. In this paper, we perform a numerical modeling with the finite element method, using PLAXIS software, of the interaction deep excavation-diaphragm wall-soil-structure in the case of non linear soil behavior. We focus our study on a comparison of the results given respectively by two and three dimensional modelings. This allows us to give some recommendations concerning the validity of twodimensional study. We perform a parametric study according to the initial loading on the structure and the struts number.
Numerical Analysis of Slopes Stability and Shallow Foundations Behavior at Crest under Real Seismic Loading - Reinforcement Effect
Authors: Mekdash Hani , Hage Chehade Fadi , Sadek Marwan , Massih Dalia Abdel , El Hachem Elie , Youssef Emile
Published: September 2011

The aim of this paper is to analyze the slopes stability under seismic loading using a global numerical dynamic approach. This approach allows important parameters that are generally ignored by traditional engineering methods such as the soil deformability, the dynamic amplification, non linear soil behavior, the spatial and temporal variability of the seismic loading and the reinforcement element… The present study is conducted by using measures recorded during real earthquakes (Turkey, 1999) & (Lebanon, 2008). Elastoplastic soil behavior analysis leads to monitor the evolution of the slope state after an earthquake and to clarify the most probable failure circles. A parametric study according to the reinforcement length, position, inclination and the number of elements has been studied in order to define the optimal reinforcement scheme for slopes under seismic loading. This study contains also the stability analysis of an existing foundation near the slope’s crest. It will focus on the reinforcement in order to give recommendation for the most appropriate scheme that minimize the settlement of the foundation due to earthquake effect.
Prediction of Creep Behaviour of the Hybrid Composite Material Using the Accelerated Characterisation Method
Authors: Larbi Said , Berradj Mohamed , Djebbar Arezki , Bilek Ali
Published: September 2011

We present in this study a creep behavior in flexure of a hybrid composite consisting of a polyester matrix containing methyl methacrylate reinforced by two bidirectional fabrics. The first one is made with E-glass fibers and the second one is made of a knitted polyamide 66. The mass fractions are 13% for the glass fabric and 9% for the polyamide fabric. The specimens, of dimensions (L = 60, l = 15 and h = 2.3 mm) containing 06 alternating layers (2P/2V/2P) were fabricated by using the vacuum bag molding method. Bending tests performed at different temperatures allowed us first to determine the load levels for the creep tests. Creep tests at different loads (5 to 43 MPa) and different temperatures (23 ° to 80 ° C) show a noticeable increase of creep deformation for both tests under the same load and different temperatures just as those carried out at different loads under the same temperature. The initial deformation varies significantly with the load but very little with temperature. The application of the Findley model shows good correlation with experimental results. Model parameters were identified. Creep deformation satisfies the principle of superposition time-temperature-stress (TTSSP). Findley's model has subsequently been coupled with the principle of superposition of time-temperature-stress to plot master curves at different stresses and temperatures; this enables prediction of creep deformation in the long term.
Conception and Construction of Biaxial Apparatus for Identification of Axial Orthotropic Material
Authors: El Ghoche Haissam
Published: September 2011

Plastbloc is a new process. Its principle is to use compressed and ligatured blocks made of plastic materials. These blocks could be used to build lightweight embankments, to minimize loads on underground pipes and behind retaining walls. Because the compressing during the making of blocks is unidirectional, this material is made up of stake of layers. In this case, it has an axial orthotropy. With the purpose to study the rheological behavior of this material, a large number of simple compression tests were carried out. But the identification of all parameters is possible by realization of biaxial tests. A biaxial apparatus conceived specially for this type of material was built. Preliminary studies showed the good function of this apparatus. Then, biaxial tests were carried out and the characteristic functions were identified.
Linearization of a Viscoelastic Model for Light-Weight Embankment
Authors: El Ghoche Haissam
Published: September 2011

A new process of light-weight embankment by using parallelepipedal blocks which made up of plastic films in order to obtain a density of 0.4, 0.5 or 0.6. The experimental and theoretical studies of this material enabled us to elaborate a nonlinear viscoelastic model. It shows clearly the real behavior, but it needs the identification of a great number of parameters. The purpose of this paper is to simplify the model by linearzing it. This linearization was carried out for a specific density (0.6) in two ways: - Adoption of linear forms of the elastic and delayed deformations according to the stress. - Adoption of a linear form of the elastic deformation and a constant delayed one (linear viscoelasticity). The comparison between experience and theory shows that the linear model describes the reality in a field of stresses which can reach 200 kPa.
Innovative Lime-Pozzolana Renders for Reconstruction of Historical Buildings
Authors: Vejmelková Eva , Máca Petr , Konvalinka Petr , Černý Robert
Published: September 2011

Bulk density, matrix density, open porosity, compressive strength, bending strength, water sorptivity, moisture diffusivity, water vapor diffusion coefficient, thermal conductivity, specific heat capacity and thermal diffusivity of two innovative renovation renders on limepozzolana basis are analyzed. The obtained results are compared with reference lime plaster and two commercial renovation renders, and conclusions on the applicability of the particular renders in practical reconstruction works are drawn.