bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the Origin of Iabmella-Like Inhmog Ities in Owupled Laser-Semiccnducior Interacticns
Authors: Sipe J.E. , Youn Jeff F. , Van Driel H.M. 
Published: March 2011

ABSTRACTNear the threshold for laser-induced melting of semiconductors like Si and Ge, the resulting surface morphology is characterized by spatial inhcaogeneities. For cw illumination, several authors have observed the formation of randan, microscopic lamellae interspersed with molten regions, for incident fluences between threshold and approximately twice threshold.We demonstrate experimentally that such lamellae also form under pulsed conditions for 20nsec, 1.06μ pulses incident on Ge.Theoretically, we consider the simpler case of cw illumination on a bulk sample: We show that, although in principle it should be possible to form uniform melt layers of arbitrarily small thickness, for melt depths less than the skin depth of the radiation in the liquid any spatial modulation of the liquid-solid interface leads to instabilities in the coupled laser-material system.These instabilities would result in runaway inhamogeneous heat flow and hence to the formation of lamellae.Three distinct types of instabilities are identified for melt-front penetrations of less than ∼l000Å in Ge.
Laser Direct Write Technologies as Tools for Gate-Array Development*
Authors: Silversmith D. J. , Ehrlich D. J. , Tsao J. Y. , Mountain R. W. , Sedlacek J. H. C. 
Published: March 2011

ABSTRACTUsing CMOS, poly-Si gate, single-level metal, gate-array chips, techniques have been developed to reconfigure the interconnect metallization on individual circuits without degradation of device or circuit performance. These techniques involve a laser-assisted capillary wet-etch process for highly selective removal of Al-alloy interconnects and laser CVD of doped poly-Si links. This technique may be useful for prototyping, testing and optimization of gate-array and standard-cell designs and layouts.
Uv Laser-Initiated Deposition of Al2O3 Films: The Effect of Surface Irradiation
Authors: Deutsch T. F. , Silversmith D. J. , Mountain R. W. 
Published: March 2011

ABSTRACTThe effects of 193 and 248 nm UV surface irradiation on the properties of Al2O3 films produced by UV laser-initiated deposition have been investigated using ellipsometry and electrical measurements. The UV irradiated region shows a higher refractive index than the unirradiated regions, indicating that densification has occurred. Energy fluences as low as 1 mJ/cm2, too low to cause significant transient heating, produce measurable effects. The results suggest that UV irradiation may be used to obtain lower deposition temperatures in a variety of deposition systems.
Interfacial Effect in Water-Infiltrated Nanoporous Media
Authors: Chen Zhongshan , Jiang Fangxing , Li J. C. M. 
Published: March 2011

AbstractWater infiltrated nanoporous glasses have a damping peak at about 1 Hz (4.6 nm pore size) and 6 Hz (8.8 nm pore size) at room temperature; their relaxation strengths are consistent with the damping mechanism in which water flows from the regions of compression to those of tension. However, the damping peaks disappear when water content is below 60% for the 4.6 urn pore size glass and 40% for the 8.8 urn pore size glass. These water contents correspond to about a 0.85 and 1.0 urn thick interfacial water layer on the internal surfaces of the nanoporous glasses. The adsorbed layer contributes only to the damping background. Finally, dependencies of relaxation time on sample thickness, bulk modulus and viscosity agree well with the predictions of the model.
Esm Method and Laplace Transform of Klafter-Bluken Equation for Det Analysis in Polyker Blend Like Naterials.
Authors: Pekcan önder 
Published: March 2011

AbstractFluorescence decay curves from particles composed of poly(vinyl acetate) (PVAc) and naphthalene (N) labelled poly (2-ethylhexyl methacrylate) (PEHMA) were analyzed for Direct Energy Transfer (DET) from N to anthracene by the exponential series method(ESM). An averaged apparent dimension of d=2.0 were observed. The Laplace transformed Klafter-Blumen(KB) equation for the lifetime distribution was used to interpret these dimensions. Additional fluorescence experiments were carried out on Polymer films composed of the same material above. Exposure of the films to a pentane solution of 9-anthrylmethyl pivalete (AMP) transferred the AMP molecules exclusively to the PEHMA phase of the material. ESM analysis together with transformed KB equation showed that PEHMA thread has a unique dimension of 1.3 in PVAc matrix of this polymer film.
A New Mechanism for Lubrication in Liquid Crystals
Authors: Bruinsma Robijn F. , Safinya Cyrus R. 
Published: March 2011

AbstractRecent synchrotron X-ray scattering studies on the thermotropic liquid crystal lubricant 8CB under shear flow have shown that for high shear rates the smectic layers are oriented perpendicular to the orientation assumed by conventional solid layered lubricants. This result invalidates existing theories of the lubrication mechanism of these materials. We show that the new orientation is the result of flow deformation of thermal fluctuations. This same mechanism is found to create a “normal stress” lift-force which we propose as the new lubrication mechanism.
The Influence of Local Magnetization on Transport in Cd0.91Mn0.09Te:In
Authors: Molnar S. Von , Penney T. , Terry I. , Becla P. 
Published: March 2011

AbstractWe describe the influence of local magnetization on electron localization and transport properties on the insulating side of the metal insulator transition in the dilute magnetic persistent photoconductor Cd0.091Mn0.09Te:ln. Measurements of both the temperature dependence of the transport properties, and also the dielectric constant, are reported for just one sample in which the carrier concentration n was varied by photodoping. From these results we are able to extract the carrier concentration dependence of the localization length and the permitivity of the electrons. We also report onl a new transport effect which occurs at ultra low temperatures and/or carrier concentrations very close to the metal insulator transition. We find that this mechanism is totally magnetic in origin and are able to explain it in terms of the well devewloped ideas of magnetic polarons in magnetic semiconductors.
Phasie Transitions in Confined Molecularly-Thin Films
Authors: Cushman John H. , Diestler D. J. , Schoin M. K. 
Published: March 2011

AbstractPhase changes in Lennard-Jones (IJ) and Stockmayer fluids confined between two parallel fcc (100) planes of rigidly fixed IJ atoms are studied by means of mixed isostress-isostrain canonical and isostrain grand-canonical Monte Carlo methods, and a microcanonical ensemble molecular dynamics technique. A nonequilibrium continuum thermodynamic derivation of the constitutive laws for the basic slit-pore model is developed and an equilibrium statistical thermodynamics anolog is reviewed. Independent constitutive parameters are chosen from the list T, μ, Ēv or their thermodynamic duals μ, N, Tij where T is absolute temperature, μ is the chemical potential, Ēv is the infinitesimal strain tensor, N is the particle number, μ is the entropy and Tij is the Piola stress tensor.Relaxation in monolayer films is studied via mean square displacement of an atom. The vicinal atoms are found to diffuse anomolously slow in accordance with a power-law relation.
Biomimetic Process for Preparing Magnetite Fibers
Authors: Lawton Carl W. , Shields Christopher S. 
Published: March 2011

AbstractTwo different biomimetic strategies were utilized in the formation of magnetite fibers. The first strategy utilized natural (Sphaerotilus natans sheaths) or synthetic (hollow fibers) matrices for magnetite formation. The second strategy made use of an iron-hydroxide intermediate that was subsequently chemically converted to magnetite within the biomimetic matrix. The formation of magnetite was determined by both visual and x-ray diffraction analysis. This process has advantages over conventional routes because of the expense and handling problems associated with the production of ceramic whiskers and fibers. The magnetite formed by this process may prove to have unique properties due to its unusual fiber structure.
Comparison of Single and Double Stranded Dna Binding to Polypyrrole.
Authors: Pande Rajiv , Lim Jeong - Ok , Marx Kenneth A. , Tripathy Sukant K. , Kaplan David L. 
Published: March 2011

AbstractThe polycation conducting polymer, oxidized polypyrrole (PPy), possesses the ability to form complexes with DNA. Our previously proposed diffusion limited binding model for double helical DNA was also found to be applicable to single stranded DNA in this study. Single stranded DNA was found to bind PPy at a nearly identical level to that of double helical DNA. An investigation of electropolymerized PPy film morphology using SEM revealed two distinctly differing surface morphologies for the Platinum (Pt) electrode face (smooth) and polymeric growth face (rough). The DNA uptake levels were found to be consistently different on either surface, being higher on the rough surface. DNA penetrated into the disk interior with increasing time periods of exposure while a similar phenomenon but to a lesser extent was observed for single stranded DNA.
The Enzymatic Mediated Polymerization of Phenol and Aniline Derivatives on a Langmuir Trough
Authors: Bruno Ferdinando F. , Akkara Joseph A. , Samuelson Lynne A. , Kaplan David L. , Marx Kenneth A. , Tripathy Sukant K. 
Published: March 2011

AbstractEnzymatic polymerization of a number of monomers in an ordered lattice on a Langmuir trough (L-T) was investigated. The assembly and polymerization of two mixed monomeric systems consisting of 4-tetradecyloxyphenol (C14PP) with phenol, and 4-hexadecylaniline (C16PA) with aniline, in various ratios were carried out. Polymerization was obtained with C14PP and phenol (in the ratio 1:10), and C16PA and aniline (in the ratio 1:2) on buffered MilliQ water (pH 7.5) using the enzyme horseradish peroxidase (HRP) at 20°C. Polymerized monolayers were then transferred to appropriate substrates for UV-Vis, third order non linear optical (NLO) properties, and thickness measurements. Thermogravimetric analysis (TGA) was performed on the final polymers. Results suggest that the lattice controlled polymerization results in highly ordered conjugated polymers with improved functional, electronic, NLO and processability properties, which form a basis for intelligent materials design and applications.
Formation of Silk Monolayers
Authors: Muller Wayne S. , Samuelson Lynne A. , Fossey Stephen A. , Kaplan David L. 
Published: March 2011

AbstractCast silk membranes exhibit useful properties. However, there is limited control over the molecular architecture in these structures. The Langmuir-Blodgett technique can enhance the control of the membrane structure and allow improved control over membrane properties. We have formed natural silk monolayers using the Langmuir technique. Silk fibroin, regenerated from Bombvx mori cocoons, formed stable monolayers evident from pressure/area isotherms. Multilayers of the silk fibroin monolayers were deposited on a number of substrates and characterized. Transmission Electron Microscopy (TEM) and ellipsometry data provide basic information about the physical characteristics of the monolayer. Preliminary analysis of electron diffraction data of the monolayer indicate polycrystalline structure, consistent with the known structure of silk. Infrared spectrometric analysis of the monolayer using Attenuated Total Reflectance (ATR) gave wavenumbers for Amide I, II, III and V bands which compare with the silk II conformation reported for cast silk membranes.
The Physical Properties of a Hyaluronic Acid Based Bioresorbable Membrane for the Prevention of postsurgical Adhesions
Authors: Greenawalt K. , Masi L. , Muir C. , Burns J. 
Published: March 2011

AbstractWe have evaluated the physical properties and animal efficacy of a hyaluronic acid (HA) based bioresorbable membrane for the prevention of post-surgical adhesions. Test methods were developed to measure the dry and wet tensile properties and ia Xilm tissue adhesiveness of the membranes. The thin membranes were found to have sufficient strength and flexibility in the dry state for surgical handling. When hydrated in buffered saline, the membranes became weaker and more elastic. The membranes exhibited a high degree of tissue adhesiveness and significantly reduced adhesion formation in a rat cecal abrasion model.
Preliminary Characterization of Resilin Isolated from the Cockroach,Periplaneta Americana
Authors: Lombardi Elizabeth Craig , Kaplan David L. 
Published: March 2011

AbstractWe would like to mimic the mechanical properties of animal systems for the development of novel materials. Insect cuticle serves as one source of inspiration for the design of these materials. Cuticle is composed of chitin embedded in a protein matrix which may also contain plasticizers, fillers, crosslinkers, and minerals. The specific properties of the cuticle depend on the type, amount and interactions between each component. We are renewing the investigation of the elastic cuticle, resilin. Resilin, a protein-based elastomer first described in the early 1960s, has properties which have been reported to be most like those of ideal rubbers. We have examined resilin isolated from the prealar arms of the cockroach,Periplaneta americana. The results of amino acid analysis are in good agreement with earlier data reported for resilin. A series of tryptic fragments have been isolated and sequenced. These peptides have been used for the design of oligonucleotide probes for the identification of the gene(s) from a teneral cockroach cDNA library. A biopolymer, based on one tryptic fragment, has been designed and synthesized. We are continuing to treat resilin with residue specific proteases in order to map the resilin protein.
The Adhesive Glycoprotein of the Orb Web ofArgiope Aurantia(Araneae, Araneidae)
Authors: Tillinghast Edward K. , Townley Mark A. , Wight Thomas N. , Uhlenbruck Gerhard , Janssen Eveline 
Published: March 2011

AbstractA phosphorylated, glycoprotein preparation has been obtained from orb webs of the araneid spiderArgiope aurantia. This preparation probably contains proteins from more than one gland type, but resolution of these proteins has not yet been achieved. Nevertheless, a major component appears to be the adhesive glycoprotein(s) from the adhesive spiral. A product of the aggregate glands, this glycoprotein(s) occurs as discrete nodules along the core fibers of the adhesive spiral, within the viscid, aqueous droplets.The glycoprotein preparation has a high apparent molecular weight (> 200 kDa) and is polydisperse. The only monosaccharide constituent identified by gas-liquid chromatography or in lectin studies isN-acetylgalactosamine and this is at least primarilyO-linked to threonine. By electron microscopy, linear, unbranched and apparently flexible filaments are observed. Phosphorylated serine and threonine residues are present in the preparation and glycine, proline and threonine together account for about 57 mole % of the preparation's amino acid content. Thus, in some, but not all, respects, this glycoprotein preparation is reminiscent of a secretory mucin.
Luminescent Properties of Polymer Electrolytes Modified by a Rare-Earth Salt
Authors: Carlos L.D. , AssunÇĀO M. , Abrantes T.M. , Alcacer L. 
Published: March 2011

AbstractThe excitation and fluorescence spectra of PEOx EuBr3 (x=8, 16, 20, 24, 32) and PPO32 EuBr3 were recorded and analyzed in terms of the barycenters of each level of the ground septet of Eu3+. The site symmetry of the Europium ion is tentatively assigned to the C1,2, C5 or C2v cases. The maximum fluorescence intensity for each composition, together with the measured values for the lifetimes, suggest the possibility of these two polymeric electrolytes being used as fluorescent materials.
Concerted Ion and Electron Transfer Across Electronically Conductive Polymer Membranes
Authors: Martin Charles R. , Lawson Del R. , Liang Wenbin 
Published: March 2011

AbstractWe describe in this paper an experiment involving an electronically conductive polymer (ECP) which, to our knowledge, has not been described previously. A free-standing ECP (polypyrrole)-based membrane separates a solution of an electron donor from a solution of an electron acceptor. Because the ECP is both electronically and anionically conductive, the membrane can transport electrons from the donor solution to the acceptor solution, and anions in the opposite direction, such that a sustainable electron-transfer reaction is driven across the ECP membrane. We demonstrate such transmembrane electron/ion-transfer processes using both an inorganic and a biochemical electron donor/acceptor system. The biochemical case is of particular interest because we show that the reduced form of the enzyme glucose oxidase can give its electrons directly to the synthetic metal. Direct electron transfer is usually not possible at inorganic metals.
Cell Attachment and Protein Adsorption to Polypyrrole thin Films
Authors: Wong Joyce Y. , Langer Robert S. , Ingber Donald E. 
Published: March 2011

AbstractThin films of polypyrrole were synthesized using both chemical oxidative and electrochemical methods. The resulting oxidized films were characterized by UV/VIS spectroscopy, contact angle and conductivity measurements. In vitro studies suggest that extracellular matrix molecules, such as fibronectin, adsorb efficiently onto polypyrrole thin films and that 3T3 Balb/c mouse fibroblasts attach and spread normally on polypyrrole.
Voltammetric Studies of Poly(carbon disulfide)
Authors: Geng L. , Lee H.S. , Xu J. , McBreen J. , Prasad Sathya , Skotheim T.A. 
Published: March 2011

AbstractPoly(carbon disulfide) was studied by cyclic voltammetry using glassy carbon and platinum macro- and microdisk electrodes. The electron transfer kinetic is significantly faster at glassy carbon electrodes than at Pt electrodes. It is chemically reversible with moderate electron transfer rates. Voltammetric results of poly(carbon disulfide) are in good agreement with our battery testing data. The k0 value measured at a Pt microdisk electrode is 7×10−3 cm/sec. Electrochemical data suggest that PCS can be a potential cathode material for low current density lithium batteries.
Decomposition of Universal AC Ionic Conductivity Response into Two Ranges with Constant Exponents
Authors: Lim B.S. , Nowick A.S. 
Published: March 2011

AbstractMany disordered materials both crystalline and glasses show universal dynamic response [1], which is characterized by appropriate power-laws. The ac-conductivity as a function of frequency, is given by: σ(ω)=σ(0)+ Aωs where σ(0) is the dc-conductivity and the exponent s (≤1) generally decreases with increasing temperature. In previous work on ionically conducting crystals and glasses, we have observed two ranges in which s = constant, independent of temperature: at high temperatures, s=so (a value between 0.5 and 0.6) and, at low temperatures, s = 1. Further for the s = so region, the parameter A is activated with activation energy related to that of σ(0), while for the s = 1 region, A varies only slowly with temperature. For the cases of borate and silicate glasses as well as for crystalline CaTiO3 doped with 30% A13+, careful analysis was carried out over the region in which the effective s falls from 1.0 to so. The results show that this region can be described by the relation: σ(ω)= σ(0) + Aωs0 + A'ωl.0 with parameters A and A’ consistent with those obtained from the high and low- temperature regions, respectively. Thus, we conclude that two separate types of universal behavior are superimposed throughout the entire temperature region; each is described by a constant value of s, and is due to an independent mechanism of non-Debye relaxational behavior.
Molecular Dynamics Simulation of Aerogel Silica on Parallel Computers
Authors: Nakano Aiichiro , Kalia Rajiv K. , Vashishta Priya 
Published: March 2011

AbstractMolecular dynamics (MD) simulations of porous silica, in the density range 2.2 - 0.1 g/cm3, are carried out on a 41,472 particle system using two- and three-body interatomic potentials. Calculated results for fractal dimension and small-angle neutron scattering data are in good agreement with neutron scattering experiments. Results for structural correlations reveal crossovers from the short- to intermediate range (< 8 Å) and fractal to large-scale regime (10 ∼ 100 Å).The MD program simulations are carried out on distributed-memory MIMD computers using a domain-decomposition algorithm. The algorithm employs the linked-celllist method and separable three-body force calculation. The force calculation is accelerated by the multiple-time-step method. The parallel algorithm is highly efficient (parallel efficiency = 0.974), as it involves only 3 % communication overhead.
Is the Rigid-Band Model Applicable in Lithium Intercalation Compounds?
Authors: Julien C. , Balkanski M. 
Published: March 2011

AbstractNumerous layered compounds are interesting materials in which lithium intercalation occurs primarily without destruction of the host lattice. In many cases a rigid-band model is a useful first approximation for describing the changes in electronic properties of the host material with intercalation. This paper presents some recent experimental results obtained on transition-metal chalcogenide compounds and on transition-metal oxides as well. We shall observe, nevertheless, that the rigid-band model is not applicable to all of the intercalated materials. The applicability of the rigid-band model may be used as a test for the most desirable properties of a good intercalation material. This needs to be more extensively documented for their possible applications as insertion electrodes in solid state batteries.
Nafion® Membranes: Molecular Diffusion, Proton Conductivity and Proton Conduction Mechanism
Authors: Kreuer Klaus-Dieter , Dippel Thomas , Meyer Wolfgang , Maier Joachim 
Published: March 2011

AbstractH-PFG-NMR diffusion and proton conductivity data for NAFION® 117 is presented as a function of temperature and water content. From this, H2O diffusion on a molecular scale is concluded to be similar to the one in bulk water. But “geometrical” restrictions of diffusion lead to a decreasing pre-exponential factor, i.e. decreasing macroscopic diffusion coefficient with decreasing water content. It is shown that proton conductivity is correlated with water diffusion for low degrees of hydration (vehicle mechanism). With increasing hydration there is an increasing contribution from “structure diffusion” culminating in an amplification factor of A = 2.5 for fully hydrated protonic NAFION® 117 at room temperature. The bonding of water in NAFION® as well as the local environment (hydration) of the acidic proton are concluded to be similar as in acidic aqueous solutions.
Proton Conducting Solid Electrolytes for High Temperature Humidity Sensing
Authors: Greenblatt Martha , Feng Shouhua 
Published: March 2011

AbstractThe properties of various proton conducting solid electrolytes were investigated by electrochemical galvanic cell and ac impedance type measurements for applications as high temperature (T>200°C) humidity sensors. The basic characteristics of proton conductors required for humidity sensing are reviewed. Results of ionic conductivity and EMF measurements and their implications for the mechanism of ion transport are discussed for two prototype ceramic humidity sensors: β-Ca(PO3)2 and a NASICON-type ceramic composite, HZr2P3O12/ZrP2O7.