bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Thickness Dependence of Oxygen Permeability in Sol-Gel Derived Ce0.8Gd0.2O2-&#948;-CoFe2O4Thin Films on Porous Ceramic Substrates: A Sputtered “Blocking Layer” for Thickness Control
Authors: Brinkman Kyle S. , Iijima Takashi , Takamura Hitoshi 
Published: February 2009

AbstractMixed conductive oxides are a topic of interest for applications in oxygen separation membranes as well as use in producing hydrogen fuel through the partial oxidation of methane. The oxygen flux through the membranes is governed both by the oxygen ionic conductivity as well as the material's electronic conductivity; composite membranes like Ce0.8Gd0.2O2-δ(CGO)-CoFe2O4 (CFO) use gadolinium doped ceria oxides as the ionic conducting material combined with cobalt iron spinel which serves as the electronic conductor. In this study we employ ˜ 50 nm sputtered CeO2layers on the surface of porous CGO ceramic substrates which serve as solution ‘blocking’ layers during the thin film fabrication process facilitating the control of film thickness. Films with thickness of ˜ 2 and 4 microns were prepared by depositing 40 and 95 separate sol-gel layers respectively. Oxygen flux measurements indicated that the permeation increased with decreasing membrane thickness; thin film membrane with thickness on the micron level showed flux values an order of magnitude greater (0.03μmol/cm2s) at 800oC as compared to 1mm thick bulk ceramic membranes (0.003 μmol/cm2).
Ink-jet printed carbon-based micro-supercapacitor for mobile self-powered modules
Authors: Brunet Magali , Taberna Pierre-Louis , Simon Patrice , Fabre Norbert , Conédéra Véronique , Mesnilgrente Fabien , Durou Hugo , Rossi Carole 
Published: February 2009

ABSTRACTCarbon-based micro-supercapacitors dedicated to energy storage in self-powered modules were fabricated with inkjet printing technology on silicon substrate. The ink containing activated carbon with particles size ranging from 1 μm to 10 μm, mixed with PTFE and glycol was stabilised with a surfactant, Triton X100. After functionalising the electrodes surroundings with octadecyltrichlorosilane (OTS), the ink was deposited by inkjet on the electrodes with the substrate heated at 140°C in order to assure a good homogeneity. The resulting structures have a resolution of 10 μm. Micro-supercapacitors with the carbon electrodes were tested in acetonitrile and Et4NBF4 dried salts: the capacitance density obtained was 50 μF.cm−2. The newly developed technology will allow the integration of the storage device as close as possible as the MEMS-based energy harvesting device, minimising power losses through connections.
Solidification of TiAl-based alloys
Authors: Hecht Ulrike , Daloz D. , Lapin J. , Drevermann A. , Witusiewicz V.T. , Zollinger J. 
Published: February 2009

AbstractTitanium aluminides containing high niobium additions emerged as an attractive alloy family for automotive and aero-engine applications. Their processing by near net shape casting is rather demanding, not only due to easy contamination but also due to the fact that microstructure formation during solidification and subsequent solid state transformations sensitively depends on alloy composition and the applied processing conditions. The sequence of phase formation during solidification of the ternary alloy Ti-45Al-8Nb was analyzed based on non-equilibrium thermodynamic calculations and solidification experiments. This alloy solidifies completely via the β(Ti) phase, because the nucleation undercooling for the α(Ti) phase is high enough to prevent its formation. Thermodynamic calculations and experiments are shown to converge at last, with only minor improvements being necessary to correctly describe the metastable eutectic reaction “Liquid → β(Ti) + γ-TiAl” that occurs at the end of the solidification path.
Crystal Structure and Thermoelectric Properties of Mn-Substituted Ru2Si3 with the Chimney-Ladder Structure
Authors: Koyama Tatsuya , Okamoto Norihiko L. , Kishida Kyosuke , Tanaka Katsushi , Inui Haruyuki 
Published: February 2009

AbstractChimney-ladder compounds with the general chemical formula of Mn X2n-m (n, m: integers) possess tetragonal crystal structures which consist of two types of subcells; one composed of transition metal atoms (M) with the γÀ-Sn structure and the other composed of group 13 or 14 atoms (X) with a helical arrangement along the tetragonal c-axis. Since the chimney-ladder compounds generally exhibit very low thermal conductivity, presumably due to its long periodicity along the c-axis, they have been extensively investigated as promising thermoelectric materials. The high-temperature (HT) phase of Ru2Si3 is one of the chimney-ladder compounds with n=2 and m=1. Recently we have found that the HT-Ru2Si3 phase is stabilized by substituting Ru with Re so as to exist even at low temperatures in a wide compositional range of the Re content (Re: 14 to 73%), and that the thermoelectric power factor for alloys with high Re contents increases with the Re content and the highest value was obtained for the alloy with the highest Re content (73%), which is the solubility limit of Re in the chimney-ladder phase. In order to further enhance the thermoelectric properties, another ternary element which extends the solid solubility region of the HT-Ru2Si3 phase is favorable. We have chosen Mn as the ternary element because Mn4Si7 with the chimney-ladder structure exists as a counterpart of HT-Ru2Si3 in the Ru2Si3 -Mn4Si7 pseudo-binary system so that the solid solubility region of the chimney-ladder phase is anticipated to extend in a wider composition range than the Re case. Our study, in fact, shows that the Mn-substitution stabilizes the HT-Ru2Si3 phase in a wide compositional range of the Mn content; 12 to 100%. Compositional analyses indicate that the Si/M ratio gradually increases as the Mn content increases. This is considered to be due to the addition of Si atoms in the Si subcell in order to compensate the decrease in the valence electron concentrations (VEC) per M atom by the substitution of Ru (group 8) with Mn (group 7) with fewer valence electrons. The Seebeck coefficient and electrical resistivity of the Mn-substituted Ru2Si3 are explained in terms of the VEC deviation from the idealized value, 14, which is expected for intrinsic semiconductors with the chimney-ladder structure. The highest dimensionless thermoelectric figure of merit (ZT=0.76) is obtained for 90%Mn-substituted alloy. The relationships between the microstructure and thermoelectric properties will be discussed.
Consolidation and Mechanical Properties of Mechanically Alloyed Al-Mg Powders
Authors: Sakaliyska Mira , Scudino Sergio , Nguyen Hoang Viet , Surreddi Kumar Babu , Bartusch Birgit , Ali Fahad , Kim Ji Soon , Eckert Jürgen 
Published: February 2009

AbstractNanostructured Al-Mg bulk samples with compositions in the range of 10 – 40 at.% Mg have been produced by consolidation of mechanical alloyed powders. Powders with composition Al90Mg10and Al80Mg20were consolidated into highly dense specimens by hot extrusion. Room temperature compression tests for the Al90Mg10specimen reveal interesting mechanical properties, namely, a high strength of 630 MPa combined with a plastic strain of about 4 %. The increase of the Mg content to 20 at.% increases the strength by about 100 MPa but it suppresses plastic deformation. The Al60Mg40powder was consolidated at different temperatures by spark plasma sintering and the effect of the sintering temperature on microstructure, density and hardness have been studied. The results reveal that both density and hardness of the consolidated samples increase with increasing sintering temperature, while retaining a nanocrystalline structure. These results indicate that powder metallurgy is a suitable processing route for the production of nanocrystalline Al-Mg alloys with promising mechanical properties.
Role of the Microstructure on the Deformation Behavior in Mg12ZnY with a Long-Period Stacking Ordered Structure
Authors: Hagihara Koji , Yokotani Naoyuki , Kinoshita Akihito , Sugino Yuya , Yamamoto Hiroyuki , Yamasaki Michiaki , Kawamura Yoshihito , Umakoshi Yukichi 
Published: February 2009

AbstractThe influence of a heat-treatment on the plastic deformation behavior in Mg12ZnY with a long-period stacking ordered (LPSO) structure was investigated by using crystals grown by the Bridgman method. Annealing of the crystal at 798 K for 3 days induced the change in the crystal structure of Mg12ZnY from the 18-fold rhombohedral structure (18R) to the 14-fold hexagonal structure (14H). The plastic behavior of those LPSO crystals showed a large variation depending on the loading axis in both crystals, because of the limitation of operative deformation modes in them. The change in the stacking sequence in the LPSO crystals did not show a large influence on the plastic deformation behavior at room temperature.
Thin-Film Synthesis and Cyclic Oxidation Behavior of B2-RuAl
Authors: Woll Karsten , Chinnam Rama , Mücklich Frank 
Published: February 2009

AbstractB2-RuAl as a potential intermetallic for thin-film applications at high temperatures is studied with respect to thin-film synthesis and cyclic oxidation behaviour. Using the multilayer approach, single phase RuAl thin films were fabricated. The phase sequence from the elements Ru and Al goes through RuAl6 to the final product RuAl. To understand the reaction mechanism calorimetric as well as kinetic experiments were performed. The cyclic oxidation behavior is characterized at 1200 °C up to 47 h. The morphology of the grown alumina shows no cracks or regions of spallation which indicates the good cyclic oxidation behavior. Compressive stresses in the oxidation scale of about 1.2 GPa at maximum were determined.
The European ULTMAT Project: Properties of New Mo- and Nb-Silicide Based Materials
Authors: Drawin Stefan 
Published: February 2009

AbstractThe development, in the frame of the European ULTMAT project, of alloys offering at least 150°C surface temperature increase above the Ni-based superalloys' capability is presented. The expected achievement of the project is a thorough evaluation of the capability of refractory metal (Nb and Mo) silicide based multiphase materials to withstand enhanced temperature turbine service conditions (up to 1300°C). This is based on microstructural, mechanical, physical and environmental investigations in close connection with industrial scale material processing and component fabrication technologies. The paper presents an overview of the project results. Base materials are the metal/intermetallic ductile/brittle composites in the Nb-Nb5Si3 and Mo-Si-B systems. Improvements in high temperature creep resistance (up to 1300°C) as well as oxidation resistance (700°C to 1300°C) have been obtained. Processing routes have been developed (ingot and powder metallurgy) that allowed the manufacture of complex shaped parts.
Metastable Hexagonal Modifications of the NbCr2 Laves Phase as Function of Cooling Rate
Authors: Aufrecht Jochen , Leineweber Andreas , Mittemeijer Eric Jan 
Published: February 2009

AbstractIn as-cast ingots produced by arc-melting, several metastable polytypic modifications of NbCr2 were found additional to the cubic C15 phase stable at room temperature: C14, C36 and 6H-type structures, often highly faulted and/or intergrown. Strikingly, these phases had formed at locations of the specimen which had experienced a relatively low cooling rate, whereas the C15 phase was formed preferentially in regions which had experienced the highest cooling rates.
Phase Equilibria in the Ternary Nb-Cr-Al System and Site Occupation in the Hexagonal C14 Laves Phase Nb(AlxCr1-x)2
Authors: Prymak Oleg , Stein Frank , Kerkau Alexander , Ormeci Alim , Kreiner Guido Michael , Frommeyer Georg , Raabe Dierk 
Published: February 2009

AbstractThe ternary Nb-Cr-Al phase diagram exhibits extended phase fields of the cubic C15 and the hexagonal C14 Laves phases Nb(AlxCr1-x)2. A number of Nb-Cr-Al alloys were prepared by levitation melting and annealed at temperatures between 1150 and 1450 °C for up to 1500 h. Isothermal sections of the ternary Nb-Cr-Al phase diagram at 1150, 1300 and 1450 °C were obtained from electron probe microanalysis, X-ray powder diffraction and metallographic investigations in order to study the effect of Al on the stability and structure of the Laves phases. The C14 Laves phase in the Nb-Cr-Al system can dissolve up to 45 at.% Al by substituting Cr with Al on the two different crystallographic B-sites 2a and 6h of the C14 AB2 unit cell. The site occupations of the Al and Cr atoms on these two B-sites were determined by Rietveld analysis using the program FullProf. The experimental site occupation factors were compared to site occupation factors computed by a statistical mechanics approach based on first-principles electronic structure calculations. The experimental as well as the calculated site occupation factors indicate a preferred occupation of the 2a site by Al.
Variable Thickness IPMC: Capacitance Effect on Energy Harvesting
Authors: Tiwari Rashi , Kim Sang-Mun , Kim Kwang 
Published: February 2009

AbstractIonic Polymer Metal Composites (IPMCs) are manufactured by electroless deposition of metal on Nafion. This deposition method results in the IPMCs with thickness between 0.17mm to 0.20mm with the electrode thickness of around a few &#61549;m each. It is now generally accepted that on mechanical deformation IPMC produces charge thus making these materials potentially suitable for energy harvesting applications. Due to thin metal plating and inherited flexibility of the Nafion film the IPMCs suffer in stiffness that may be required for some energy harvesting applications. Also earlier works have shown that 0.20mm thick IPMC produce better battery charging than 0.17mm thick one. Hot pressing, using metal mold, Nafion films was employed to produce thicker and comparatively stiffer IPMCs electroded with Palladium metal. Palladium was used because of shorter manufacturing time. This IPMC shows improved energy harvesting. Due to the increased thickness these IPMCs also function as better capacitors than their conventional counterparts. On application of voltage, these IPMCs show charging and discharging effects of a capacitor. This property of IPMC may be useful for storing charge.
Electrical and Optical Properties of Gold-strontium Titanate Nano-composite Thin Films
Authors: Ganti S , Dhopade Y , Gupta R K , Ghosh K , Kahol P K 
Published: February 2009

AbstractThin films based on nano-composites have attracted considerable attention for their possible applications in devices and sensors. These nano-composite thin films are formed by embedding metal or semiconductor nano-particles in a host material and they exhibit interesting electrical transport properties. Using pulsed laser deposition technique, we have prepared nano-composite thin films of gold-strontium titanate on quartz substrate. Gold and strontium titanate were used as targets for pulsed laser deposition. Thin films having different compositions were grown. The effect of different composition on their electrical and optical properties has been studied in details. The structural characterizations of the films were done by x-ray diffraction, transmission electron microscopy, scanning electron microscopy, and atomic force microscopy. Transmission electron microscopy as well as atomic force microscopy shows the presence of gold nano-particles in these films. X-ray diffraction and energy dispersive x-ray spectroscopy shows the existence of strontium titanate and gold. Current-voltage characteristics and temperature dependent resistivity measurements were made to characterize electrical properties of these films. Electrical properties can be manipulated from metal to insulator through semiconductor by varying the composition. In addition, it is observed that the absorption of visible light increases with increase in gold percentage. This indicates that these nano-composites could also use as active materials for many electronic as well as optical sensors.
Thermal, Mechanical, and Electric Properties of Exfoliated Graphite Nanoplate Reinforced Poly(vinylidene fluoride) Nanocomposites
Authors: He Fuan , Fan Jintu 
Published: February 2009

AbstractPoly(vinylidene fluoride) (PVDF)/exfoliated graphite nanoplate (xGnP) nanocomposites were prepared by a solution mixing method for the first time. The thermal, mechanical and electric properties of these nanocomposites were studied by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and an impedance analyzer, respectively. The DSC results indicated that xGnP might act as the nucleating agents and accelerated the overall non-isothermal crystallization process of PVDF. Meanwhile, the incorporation of xGnP also significantly improved the storage modulus and conductivity of the PVDF/xGnP nanocomposites with an increment in the graphite nanoplate content, respectively.
Mechanical Characteristics of Al-Si-Cu Structural Films by Uniaxial Tensile Test with Elongation Measurement Image Analysis
Authors: Fujii Hiroki , Namazu Takahiro , Tomizawa Yasushi , Inoue Shozo 
Published: February 2009

AbstractThis paper presents mechanical characteristics of sputtered Al-Si-Cu film used as a structural material in microelectromechanical systems (MEMS). Novel tensile test technique with an elongation measurement image analysis system has been developed. Uniaxial tensile tests were conducted at temperatures ranging from room temperature (R.T.) to 358 K. No specimen-size effect on Young's modulus, yield stress, and fracture strength, was found, whereas the annealing and temperature effects were clearly observed. To study mechanical degradation mechanism, cyclic loading tests were conducted under constant stress- and strain-amplitude modes. In constant stress-amplitude mode, stain amplitude increased with an increase of loading cycles due to creep-like deformation. Almost of the specimens fractured during the tests. Meanwhile, in constant strain-amplitude mode, stress amplitude gradually decreased with increasing cycles due to stress-relaxation, but no fatigue failure was observed.
Optical Fiber Microarrays for Chemical and Biological Measurements
Authors: Walt David R , LaFratta Christopher , Webb Michael , Li Zhaohui , Gorris Hans-Heiner , Hayman Ryan 
Published: February 2009

Abstract
We have used coherent imaging fiber arrays as a platform for preparing chemical sensors and biosensors. Sensors can be made with spatially-discrete sensing sites for multi-analyte determinations. Micrometer sized sensors have been fabricated by etching the cores of an optical imaging fiber to create microwells and loading them with microspheres. These arrays possess both high sensitivity and reproducibility and can be used for making thousands of measurements simultaneously such as for genetic analysis or for the analysis of complex biological fluids. Both optical and optoelectrochemical arrays have been used for multiplexed sensing. In another scheme, the arrays can be used for single molecule detection. In this format, individual molecules, such as enzymes, can be trapped in the microwells by sealing each microwell with a silicone gasket. The enzyme molecules catalyze the formation of a fluorescent product that can be detected readily. The kinetic properties of hundreds to thousands of single enzyme molecules can be monitored simultaneously using this format. By observing the stochastic nature of the single molecule responses, new mechanistic insights into the fundamental nature of the enzymes can be obtained.
Photonic crystals: A platform for label-free and enhanced fluorescence biomolecular and cellular assays
Authors: Cunningham Brian T. , Chan Leo , Mathias Patrick C. , Ganesh Nikhil , George Sherine , Lidstone Erich , Heeres James , Hergenrother Paul J. 
Published: February 2009

Abstract
Photonic crystal surfaces represent a class of resonant optical structures that are capable of supporting high intensity electromagnetic standing waves with near-field and far-field properties that can be exploited for high sensitivity detection of biomolecules and cells. While modulation of the resonant wavelength of a photonic crystal by the dielectric permittivity of adsorbed biomaterials enables label-free detection, the resonance can also be tuned to coincide with the excitation wavelength of common fluorescent tags - including organic molecules and semiconductor quantum dots. Photonic crystals are also capable of efficiently channeling fluorescent emission into a preferred direction for enhanced extraction efficiency. Photonic crystals can be designed to support multiple resonant modes that can perform label free detection, enhanced fluorescence excitation, and enhanced fluorescence extraction simultaneously on the same device. Because photonic crystal surfaces may be inexpensively produced over large surface areas by nanoreplica molding processes, they can be incorporated into disposable labware for applications such as pharmaceutical high throughput screening. In this talk, the optical properties of surface photonic crystals will be reviewed and several applications will be described, including results from screening a 200,000-member chemical compound library for inhibitors of protein-DNA interactions, gene expression microarrays, and high sensitivity of protein biomarkers.
Surface Plasmon Enhanced Transmission with Self-assembled Hexagonal Nanohole Arrays
Authors: Lou Yi , Westcott Nathan , McGlade John , Muth John F. , Yousaf Muhammad 
Published: February 2009

Abstract
The optical properties of hexagonal nanohole arrays in gold films are investigated. Nanosphere lithography combined with reactive ion etching has been applied as a low cost method to fabricate nanohole arrays with hexagonal symmetry where the size and spacing of the holes can be independently controlled. In this study, the spacing between the nanoholes is 600 nm with the hole diameter varied between 450 and 250 nm. The transmission spectra of the surface patterns with different film thickness are collected with normally incident light. The color of the reflected light from the nanohole array was found to change from green to red as the diameter of the holes was reduced. One application of these films is to study cell adhesion to small areas with controlled size. We explore the possibility of making isolated cell adhesion dots by chemically modifying the nanohole area. Swiss 3T3 cells were adhered onto the patterned surface and imaged using environmental SEM and fluorescent microscopy.
Interplay Between Surface Chemistry and Optical Behavior of Semiconductor-biomolecule Functionalized Sensing Systems: An Optical Investigation by Spectroscopic Ellipsometry
Authors: Losurdo Maria , Wolters Scott D , Giangregorio Maria M , Lisco Fabiana , Angelo Michael , Lampert William , Bruno Giovanni , Brown April 
Published: February 2009

Abstract
Chemical functionalization of bio-molecules, including hemin (an iron porphyrin) and bovine albumin onto Si (100) and GaAs (100) surfaces is reported. Spectroscopic ellipsometry analysis on the optical response of functionalized surfaces provides information on molecular coverage and effective thickness as well as the kinetics of surface attachment. Topographic features of the chemically functionalized surfaces are investigated by atomic force microscopy
Molecular Adsorption and Fragmentation of Bromoform on Polyvinylidene Fluoride with Trifluoroethylene
Authors: Ilie Carolina C. , Xiao Jie , Dowben Peter 
Published: February 2009

AbstractBromoform absorption on crystalline polyvinylidene fluoride with 30% of trifluoroethylene, P(VDF-TrFE 70:30) was investigated by photoemission and inverse photoemission and found to be associative and reversible. Molecular bromoform adsorption appears to be an activated process at 120 K with enhanced adsorption following the initial adsorption of bromoform. Strong intermolecular interactions are also implicated in the presence of a weak shake off or screened photoemission final state.