bluuebunny/crossref_metadata_2025_split huggingface dataset:
Susceptibility Study of Site Selective Doped Fullerenes - K2RbC60, Rb3C60, K2CsC60, and Rb2CsC60
Authors: Baenitz M. , Heinze M. , Lüders K. , Werner H. , Schlögl R. 
Published: April 2011

ABSTRACTThe superconducting properties of several binary and ternary fullerene compounds are investigated by means of ac susceptibility technique. The susceptibility X = X'-iX” is observed as a function of temperature for different magnetic field amplitudes (0.01 G - 20 G). The samples are characterized by X-ray diffraction (XRD) analysis and the fcc-lattice constants a0 are determined. Furthermore the influence of the preparation procedure, especially the treatment of the C60 starting material on the superconducting properties is discussed.
Plasma Potential Measurements and Strain Effects in Epitaxial GAN Grown on AlN Buffered Si(111) by Radio Frequency Reactive Sputtering
Authors: Meng W. J. , Perry T. A. 
Published: April 2011

AbstractWe have grown epitaxial GaN thin films on A1N buffered Si(lll) by radio frequency glow discharge sputtering. GaN growth direction strains and GaN E2 optical phonon energies are measured. At the same growth temperature, plasma potentials of the radio frequency glow discharge in which GaN is grown, GaN growth rate, and strain in GaN increase systematically as a function of increasing input power. The measured GaN E2 optical phonon energy scales with GaN lattice strain. Our results indicate the presence of significant intrinsic stresses in epitaxial GaN films and point to the importance of plasma characteristics in controlling the physical properties during plasma assisted thin film deposition.
Determining Interfacial Free Energies from Creep Experiments on Silver-Iron Multilayers
Authors: Josell D. , Wang Z.L. 
Published: April 2011

AbstractExperiments were conducted on multilayer thin films to determine the free energies associated with silver/iron interfaces. Creep studies determined the loads for which the multilayers neither shrank nor stretched over time. Microstructural data was used with the zero creep loads in a model for grain boundary diffusion controlled creep in multilayers to determine the interfacial free energy.
Mechanical Properties of Ag/Cr Multilayered Epitaxial thin Films
Authors: English Gerald R. , Simenson Glenn F. , Clemens Bruce M. , Nix William D. 
Published: April 2011

AbstractMetallic multilayer thin film structures exhibit very high hardnesses. The epitaxial Ag/Cr system was chosen to investigate the mechanisms responsible for these high hardnesses. The interfaces of this multilayer structure are expected to be chemically abrupt since silver and chromium are nearly immiscible and do not form intermetallic compounds. The crystallographic structure formed by epitaxial growth isolates the slip systems of each layer.The samples were deposited on (001) MgO substrates by sputter deposition at room temperature. The bilayer spacing of the samples ranges from 1 nm to 20 nm. X-ray diffraction results indicate that the multilayer films exhibit the rotated (001) crystal structure. Hardness and indentation modulus were measured by depth-sensing indentation experiments using a Nanoindenter. The maximum hardness is roughly four times the weighted average of the single component films. The indentation modulus at small bilayer periods varies by ±15% from the value at large bilayer periods, but all of the values fall between the moduli measured for the single component films.Decreasing the bilayer period increases the hardness. At bilayer spacings smaller than 4 nm, the hardness remains constant. Decreasing the thickness of the Cr layer while keeping the thickness of the Ag layer at 5 nm, increases the strength of the multilayered film. At Cr thicknesses smaller than 5 nm, the hardness decreases as the Cr thickness decreases. The effect of the volume fraction of Cr on film strength was also studied.The results are discussed in the context of a deformation model in which the dislocations responsible for deformation are constrained to move in the individual layers. From this model, a lower bound on the strength of the multilayered film can be calculated if plastic deformation occurs in only one layer. An upper bound can be calculated if plastic deformation occurs in both layers. The data fall between the upper and lower bounds and lie closer to the lower bound.
Measurement of the Dependence of Stress and Strain on Crystallographic Orientation in Cu and Al thin Films
Authors: Zielinski E. M. , Vinci R. P. , Bravman J. C. 
Published: April 2011

AbstractThe orientational dependence of stress and strain was measured for (111) and (110) oriented grains in an Al thin film which hillocked upon heating, and (111) and (100) oriented grains in Cu thin films, one of which exhibits abnormal (100) grain growth. Results from the Al thin film were inconclusive in the evaluation of the Sanchez model for hillocking, however they indicate that the Nix model for the orientational dependence of yield stress is not applicable to individual grains at room temperature. Results from the Cu thin films suggest that suppression of (100) abnormal grain growth is due to isostress averaging among the grains of varying orientation.
Stress Relaxation in Al-Si-Cu Thin Films and Lines
Authors: Witvrouw A. , Proost J. , Deweerdt B. , Roussel Ph. , Maex K. 
Published: April 2011

AbstractSubstrate curvature measurements were used to study stress relaxation in Al-Si-Cu films at temperatures between 45 and 165 °C. Dislocation glide with an average activation energy, resp. athermal flow stress of 1.7 ± 0.2 eV, resp. 600 ± 200 MPa could describe the relaxation data for temperatures up to 120 °C well. Stress relaxation at 92 °C was found to progress much slower in 1 μm wide nitride passivated lines than in thin films or unpassivated lines.
The Effect of Intrinsic Passivation Stress on Stress in Encapsulated Interconnect Lines
Authors: Mack Anne Sauter , Flinn Paul 
Published: April 2011

AbstractThe stress in an encapsulated metal line has been calculated using the finite element technique for two passivation stress conditions. It is found that the stress-state in the passivation has a negligible effect on the stress in the metal line. The dominant factors affecting metal line stress are the passivation temperature, the thermal expansion coefficient difference between the metal line and the substrate, and the passivation modulus.
Elastic Properties and Stresses in Polyimide thin Films and Coatings
Authors: Sheth Kapil C. , Chen Michael , Farris Richard J. 
Published: April 2011

AbstractPolyimide thin films and coatings (< 20μm) for electronic applications have been fully characterized. Analysis of residual stresses and determination of all 21 anisotropic constants are necessary for a better understanding of these coatings in complex geometries. The residual stresses have been measured by a real-time vibrational holographic interferometry technique. The number of elastic constants is reduced to 9 independent constants by finding the orthotopic axes. All the 9 orthotropic constants - 3 normal compliances, 3 shear compliances and 3 independent Poisson’s ratios - have been determined. Moisture diffusion constants have also been measured.
Development of A Technique for the In-Situ Measurement of the Mechanical Properties of Ultra-Thin Interfacially Polymerized Films
Authors: Greenberg Alan R. , Khare Vivek P. , Krantz William B. 
Published: April 2011

AbstractCrosslinked polyamide barrier layers made by a self-limiting interfacial polymerization (IP) process are extremely thin (= 1000 Å), relatively defect-free and possess excellent perm selective properties which enable their commercial application in thin film composite (TFC) membranes. Little information has been reported in the open literature concerning the physical as well as mechanical properties of these polyamide IP films due to the substantial difficulties in making direct measurements on such thin crosslinked materials. Consequently, the development of IP-TFC membranes for commercial separations has been largely a trial-and-error process.We are developing a novel experimental technique, Pendant Drop Mechanical Analysis (PDMA) that utilizes the capabilities of the pendant-drop tensiometer for in-situ measurements of the mechanical behavior of the IP films. The current effort focuses on relating the mechanical behavior of the IP films to their structure, which in turn will be related to the permselective performance. Preliminary PDMA results indicate significant differences in the mechanical behavior of the IP films as a function of composition and contact time. These differences can be related to changes in the network characteristics.
Measurements of Elastic Modulus Using Laser-Induced Surface Waves
Authors: Chang D. J. , Amimoto S. T. , Gross R. W. , Glenn T. S. 
Published: April 2011

AbstractMeasurements of the elastic modulus of fused silica, 6061-T6 and 7075-T651 aluminum alloys, GaAs, Ge, and Si samples are reported. A pulsed laser is used to generate surface acoustic waves in a sample and the wave velocity is measured using a knife-edge detection method. From the velocity of the surface waves the elastic modulus can be calculated.[1] Extension of this work to thin films is discusssed.
Photoacoustic Method for Obtaining Strength Characteristics of Thin Films
Authors: Konovalov I. A. , Sklyarenko S. K. 
Published: April 2011

AbstractLocal thermoelastic stresses appear in the surface layers of materials under pulsed laser irradiation. Changes in the amplitude and shape of acoustic signals with laser pulse intensity were studied. Changes corresponding to a transition from purely elastic to elastoplastic deformation in the zone of interaction between the radiation and surface have been registered. Measurement of the absorbed energy radiation which causes these threshold phenomena makes it possible to estimate the yield limit for plastic materials and strength limit for brittle ones.
Studies of Ultra Micro Indented Multilayered Sol-Gel Zirconia Films
Authors: Jômting Å. , Ben-Nissan B. , Ashcroft I. , Swain M. V. , Bell J. M. 
Published: April 2011

AbstractThe deformation behavior of sol-gel derived zirconia films during ultra micro indentation has been investigated. The sol-gel films were deposited using a multiple stage coating procedure onto stainless steel substrates. The indentation process was carried out using both pointed indenters, such as a Berkovich, as well as spherical indenters. The use of different indenter types enables the determination of hardness, elastic modulus as well as the elastic-plastic or elastic-brittle transition of the films. The mechanical behavior of thin films is strongly influenced by the interaction between the substrate and the film. In brittle materials, the stress singularities induced by the indentation process cannot readily be reduced by long range plastic flow and may cause cracking. Therefore, a great deal of attention has been paid to post-indentation observations of the films, in particular examinations of the surface morphology for visible traces of the film behavior during indentation.
A Tem Investigation of the Effects of Tensile Stress on Thin Film Microstructure and Surface Morphology
Authors: Harris Karen E. , King Alexander H. 
Published: April 2011

AbstractWe have studied the microscopic effects of tensile stress on film thickness and grain growth in gold thin films of 25nm nominal thickness using transmission electron microscopy. Free-standing films were annealed at 150°C resulting in films with columnar grains and 〈111〉 fiber texture. After repeated anneals, tensile stresses caused by grain growth became large enough to cause cracks to form and propagate diffusively. While tensile stress must eventually result in an overall decrease in film thickness, local specimen thickening in front of crack tips is observed. The tensile stress also profoundly affected grain growth in these films. Grains near crack tips are larger than grains 400nm away from the tips, and elongated grains with axial ratios greater than 15 have been observed in cracked regions of the films.
Evaluation of the Mechanical Properties of Tribochemical Films on Alumina
Authors: Gee M. G. , Jennett N. M. 
Published: April 2011

AbstractThis paper presents the results of the mechanical characterisation, by a mechanical properties microprobe or nanoindenter, of tribochemical films produced by the sliding wear of alumina in a humid environment.It was found that the tribochemical films were softer than the remnant alumina on the worn surfaces, and were liable to fracture and cracking under the indenter.
Amorphous Magnetoelastic Materials
Authors: Savage H. T. , Wun-Fogle Marilyn 
Published: April 2011

AbstractThe outstanding feature of amorphous magnetoelastic alloys is the controllability of the magnetic anisotropy energy, Curie point, magnetostriction and magnetic moment. This control of material characteristics, achieved by magnetic and stress annealing plus changes incomposition, is impossible in crystalline materials. The control allows the design of tactile and magnetic field sensors with special features and very high sensitivity. The materials discussed are prepared by rapid solidification through melt spinning in ribbon and wire geometries and magnetron sputtering onto substrates. As an example of the advantagesof sputtered material, an accelerometer on silicon micro-cantilevers is shown. I-t has nocoils. The basic magnetoelastic theory that governs tactile sensors is shown. Low-noise magnetic field sensors with novel twist anisotropies and Barkhausen instabilities in wiresare discussed.
Correlations Between the Bipolar- and Unipolar-Electric Field Induced Strain in Pb(Mg1/3Nb2/3)O3-PbTiO3 Ceramics
Authors: Park Jae-Hwan , Kim Byung-Kook , Park Soon Ja 
Published: April 2011

AbstractCorrelations between the strains induced by a unipolar-electric field and the strains induced by a bipolar-electric field were investigated for Pb(Mg1/3Nb2/3)O3 (PMN) and 0.9{Pb(Mg1/3Nb2/3)O3}-0.1PbTiO3 (0.9PMN- 0.1PT) relaxor ferroelectric ceramics in the temperature range of −50°C ∼ 150°C. The magnitudes of the unipolarly induced-strains are almost the same as the differences between the bipolarly induced-strains and the residual strains, which were attributed to the absence of change of spontaneous polarization direction when the unipolar-electric field is applied.
Ligand-Receptor Contact Interactions Using Self-Assembled Bilayer Lipid Membranes
Authors: Ottova A. Leitmannova , Tien H. Ti 
Published: April 2011

AbstractBiological membranes play a crucial role in signal transduction and information processing as well as in energy conversion. This is owing to the fact that most physiological activities involve some kind of lipid bilayer-based receptor-ligand contact interactions. There are many outstanding examples such as ion sensing, antigen-antibody binding, and ligand/voltage--gated channels, to name a few. One approach to study these interactions in vitro is facilitated by employing artificial bilayer lipid membranes (BLMs). We have focused the efforts on ion and/or molecular selectivity and specificity using newly available self-assembled BLMs on solid support (i.e., s-BLMs), whose enhanced stability greatly aids in research areas of membrane biochemistry, biophysics and cell biology as well as in biosensor designs and molecular devices development. In this paper, our current work along with the experiments carried out in close collaboration with others on s-BLMs will be presented.
A Theoretical Examination of Mems Microactuator Responses with an Emphasis on Materials and Fabrication
Authors: Glumac D.E. , Cooney T.G. , Francis L.F. , Robbins W.P. 
Published: April 2011

AbstractA free standing cantilever beam consisting of a support structural material (polysilicon/silicon nitride), a piezoelectric PZT ceramic layer, and metal electrode layers has been analyzed. Beam theory and finite element analysis were used to model the electric field induced deflections of this structure, and provided information as to how material choices influenced actuator function. Both support material and PZT thicknesses varied from 0-1.0 gim, and bulk piezoelectric coefficients and elastic moduli were assumed. The beam theory uses known (or assumed) material properties to predict actuator responses. Conversely, if device responses can be measured, material properties may be inferred from the theory. For a PZT thickness of 0.3 μm, a core layer thickness of 0.13 μm was found to maximize displacement. Also, the force output was found to be more dependent on the core thickness than that of the PZT. This information can then be used to predict the response of a more complex microactuator.
Fabrication and Characterization of Barium Strontium Titanate and Non-Ferroelectric Oxide Composites
Authors: Ngo E. , Stowell S. , Sengupta L.C. , O'day M.E. , Lancto R 
Published: April 2011

AbstractVarious composites of BSTO combined with other nonelectrically active oxide ceramics have been formulated. In general, the composites have adjustable electronic properties which can be tailored for use in various electronic devices. Two applications, which are of interest in regard to the composites being discussed here, are phased array antennas and capacitor-varistor monolithic devices. For the phased array antennas, these properties include reduced dielectric constants, ε′, where ε = ε′ - iε″, and loss tangents, tan δ. The reduction of the dielectric constant and lowering of the loss tangents reditce the overall impedance mismatch and the insertion loss of the device. In addition, the overall tunability, change in the dielectric constant with applied voltage, is maintained at a sufficiently high level for all dielectric constants of interest. Another application (for one of the composite materials) is a combined capacitorvaristor device. In general, this would be used to protect against spurious voltage surges and voltage transients in electronic micro-circuits. The microstructures, including grain size and phase analysis, have been examined using SEM and X-ray diffraction.
Some Durability Issues Associated with the Use of Shapememory Alloy 'Smart' Composites
Authors: Friend Clifford M. , Morgan Neil B. , Wise Vivienne D. 
Published: April 2011

AbstractThis paper presents the results from an experimental study on the durability of embedded Shape-Memory Alloy (SMA) hybrid composites. It shows that the cyclic actuation of such composites can be degraded due to the accumulation of internal damage within the host composite structure. This damage results from thermal effects within the host composite, and from mismatch in the strain capacities of the actuators and structural composite. The implications of this data for the design of embedded SMA actuator 'smart' composites is discussed.
Oxidation Resistance of TiAl Intermetallics Improved by Vacuum Aluminizing
Authors: Hsu I-Chung , Wu Shyi-Kaan , Yang Lin Ray 
Published: April 2011

AbstractTiAl binary intermetallics were aluminized in a vacuum system in order to improve their oxidation resistance. From the observations of optical microscopy and EPMA line scan, several different reaction layers were observed to be formed on respective substrates: pure Ti, Ti-32at.%Al, Ti-50at.%Al. From the results of the X-ray diffraction, the primary reaction layers were identified as TiAl3 structure in these three substrates This reacted layer grows with preferred orientation having [002] axis of TiAl3 perpendicular to the substrate surface from XRD experiments. High temperature oxidation tests revealed that vacuum aluminized layer was responsible for remarkable improvement on the oxidation resistance.
Effect of Forging Temperature on Microstructure and Tensile Properties in Fe3Al-Based Alloy
Authors: Yang Y. , Yan W. , Liu J. N. , Hanada S. 
Published: April 2011

AbstractForging processes at two different temperatures are performed to examine the relation between the microstructure and room temperature tensile properties in a Ce doped Fe3Al-based alloy. Results show that the microstructure and the ductility are sensitive to the forging temperature before annealing treatment. Higher yield strength and ductility can be obtained through forging at a relatively low temperature of 750°C followed by annealing at 800°C and 500°C. It is suggested that the formation of non-equilibrium grain boundaries and banded subgrains within carbide-free areas along grain boundaries enhances the local plastic deformation and results in the improvement of ductility. During the initial deformation at room temperature <111> slip is predominant for both microstructures.
Solid-Solution Strengthening Effect of Vanadium Addition to Iron-Modified L12 Titanium Trialuminides
Authors: Takahashi Tohru , Hasegawa Tadashi 
Published: April 2011

AbstractTwo types of aluminum–titanium–iron–vanadium ( Al–Ti–Fe–V ) quarternary intermetallic compounds have been prepared by arc melting under argon atmosphere. Their compositions were nominally Al66Ti25Fe6V3 and Al66Ti25Fe3V6. These alloys are based on the iron–modified titanium trialuminide with L12 cubic structure. Vanadium addition up to about 6 mol% did not destroy the cubic symmetry, and L12 solid solution compounds were produced in these two Al–Ti–Fe–V quarternary alloys. Microstructure and mechanical properties have been investigated. It has been demonstrated that vanadium addition to iron–modified L12 titanium trialuminides can enhance their strength.
High Temperature Deformation of a Nb-Ti-Al Alloy With σ+γ Microstructure
Authors: Ebrahimi Fereshteh , DeAragao Bernardo J. G. 
Published: April 2011

AbstractAn alloy with composition 27Nb-33Ti-40Al (at. %) was heat treated to produce a fine two-phase microstructure of σ (Nb2Al) and γ (TiAl) phases. This microstructure exhibited a peak in the flow curves obtained in the strain rate range 5 × 10−4 to 5 × 10−6s−1 at 1000°C, with a stress exponent of 3. The deformation occurred by dislocation activity and twinning accompanied by dynamic recrystallization of the γ-phase and extensive grain boundary sliding of the σ-phase, which resulted in the separation and fragmentation of the latter phase.
The Effect of Various Oxide Dispersions on the Oxidation Resistance of Fe3Al
Authors: Pint B. A. , Alexander K. B. , Tortorelli P. F. 
Published: April 2011

AbstractOxide-dispersed Fe-28at.%Al-2%Cr alloys were produced by a powder metallurgy technique followed by hot extrusion. Yttria and ceria were added to the base alloy to assess the effect of these dopants on the oxidation behavior. The amount of dopant was varied from 0.05–0.5 at.% Y in a series of Y2O2-dispersed alloys. Isothermal and cyclic oxidation testing was conducted at temperatures from 800˚ to 1300˚C. A Ce02 addition was detrimental to the oxidation behavior. The Y2O3 improved the (α-Al2O3 scale adhesion relative to an undoped alloy, but was not as effective as similar additions to an oxide-dispersed FeCrAl alloy.
Fatigue Crack Growth In Niobium Aluminide Intermetallics
Authors: Dipasquale Jeff , Gahutu David , Konitzer Doug , Soboyejo Wole 
Published: April 2011

AbstractThe results of a recent study of the fatigue crack growth in a new class of niobium aluminide (Nb3Al) intermetallics alloyed with various levels of Ti are presented. The alloys studied have the following nominal compositions (note that all compositions are quoted in atomic &): Nb-15Al-10Ti(10Ti alloy), Nb-15Al-25Ti(25Ti alloy), Nb-15Al-40Ti(40Ti alloy) and Nb-12.5A1–41Ti-1.5Mo(41Ti alloy). Fatigue crack growth behavior was studied at room-temperature in all the alloys. Fracture mechanisms were determined by inspection of SEM images of fracture surfaces. Faceted cleavage fracture modes were apparent on the lOTi and 25Ti alloys. The 40Ti and 41Ti alloys exhibited clear evidence of ductile dimpled fracture. The ductile 40Ti and 41Ti alloys are shown to have comparable or better fatigue crack growth resistance than mill annealed Ti-6A1–4V. The effects of crack orientation (relative to elongated grains) on the fatigue crack growth behavior of the 41Ti alloy are also discussed.