bluuebunny/crossref_metadata_2025_split huggingface dataset:
Increasing the Carrier Mobility in P3HT by Doping for use in Schottky Barrier TFTs
Authors: Lloyd G. C. R. , Sedghi N. , Raja M. , Lucrezia R. Di , Higgins S. , Eccleston W. 
Published: April 2011

ABSTRACTMeasurements and theory are presented examining the relationship between mobility and doping in regioregular poly(3-hexylthiophene) (P3HT). Mobility is found to increase super-linearly with doping and is comparable to models reported for other conjugated polymers. Schottky measurements have been used to calculate the doping density and bulk mobility of regioregular P3HT. Aluminium Schottky contacts showed signs of native oxide disrupting current flow through the device. This effect was observed to degrade further with the introduction of dopant into the polymer. Titanium devices show a general shift of the Schottky characteristic to higher current levels with increased dopant. Field effect mobility of P3HT films was also calculated using thin-film transistor (TFT) structures. The field effect mobility values were observed to be more than two orders of magnitude higher than the bulk mobility value. The addition of dopant also increased gate leakage currents in TFT devices. The increased conductivity in doped polymer can increase off currents in the device; this is avoided by using Schottky contacts as the source and drain. Preliminary results on Schottky contact TFTs are also presented as well as a description of the operation of such a device.
Ab Initio Study of Vibrational Anharmonic Coupling Effects in Oligo(para-phenylenes)
Authors: Heimel G. , Somitsch D. , Knoll P. , Zojer E. 
Published: April 2011

ABSTRACTIn this study we present a theoretical approach to simulate vibrational anharmonic coupling effects seen in the Raman spectra of oligo(para-phenylenes). Quantum chemical ab inito methods are applied to determine anharmonic force constants and energy corrections on the harmonic vibrational frequencies of the isolated molecules. Semiempirical methods are applied to compute Raman intensities of fundamentals and combination bands. This methodology is then used to characterize a previously unassigned Fermi resonance around 1600 cm-1. The evolution of this quantum mechanical resonance with oligomer length and planarity is compared to experimental data.
Effects of Surface Morphology of ITO Thin Film on the Instability of Organic Light Emitting Diodes
Authors: Kim Ki-Beom , Tak Yoon-Heung , Park Hyoung-Guen , Lee Kwang-Ho , Lee Jong-Ram 
Published: April 2011

ABSTRACTSurface roughness of ITO (Indium Tin Oxide) was measured by AFM (Atomic Force Microscope) and the existence of spikes was verified. Then OLED (Organic Light Emitting Diode) devices made from those substrates were fabricated and their electrical properties were measured with an I-V measurement system. There is considerable difference in the reverse leakage current of OLEDs depending on the surface roughness of the substrate. We observed a good correlation of reverse leakage current with Rpv (Peak-to-Valley roughness), but the correlations between reverse leakage current and Ra (Average roughness) and Rrms (Root-Mean-Square roughness) are not as good.
Optical Characterization of Cadmium Telluride Doped Heterostructured Opaline Photonic Crystal
Authors: Solovyev V. G. , Romanov S.G. , Torres C.M. Sotomayor , Gaponik N. , Eychmüller A. , Rogach A. L. 
Published: April 2011

ABSTRACTA double-layer photonic crystal (PhC) possessing incomplete photonic band gap (PBG) has been prepared by successive formation of one opaline film on top of another and subsequent impregnation with CdTe colloidal nanocrystals as the light source. Transmission, reflection and photoluminescence (PL) spectra of this nanocomposite have been measured from 1.8 to 2.5 eV at different angles of the light incidence and detection. The suppression of emission intensity has been found at both stop bands of the PhC heterostructure. Depending on the excitation power, either suppression or enhancement of the emission rate at the stop band has been observed.
Evaluation of The Long-Term Stability of Passive Corrosion On The Drip Shield and Waste Package Under Yucca Mountain Conditions
Authors: Shoesmith D.W. 
Published: April 2011

ABSTRACTPossible long term corrosion scenarios for the engineered barriers proposed for the Yucca Mountain (Nevada, USA) repository are reviewed.Introduction:The materials proposed for the engineered barriers in the Yucca Mountain repository (Nevada, USA), Alloy-22 for the waste packages (WP) and titanium Grade-7 (Ti-7) for the drip shield (DS), appear unlikely to suffer localized corrosion (LC) and have very low passive corrosion (PC) rates (1–3). Since environmental conditions will become more benign as temperatures decline and aqueous environments become more dilute (4), this leads to the prediction of exceedingly long waste package lifetimes. In this review, possible corrosion scenarios are discussed in the context of the anticipated evolution in the repository environment.
Solubility Evaluation for Yucca Mountain TSPA-SR
Authors: Chen Y. , Loch A.R. , Wolery T.J. , Steinborn T.L. , Brady P.V. , Stockman C.T. 
Published: April 2011

ABSTRACTA systematic evaluation of radionuclide solubility has been conducted for the Yucca Mountain Project. The conventional thermodynamic approach was employed and geochemical model calculations were used to estimate radionuclide solubilities for the base case. The study uses the computer code EQ3/6 as the major geochemical modeling tool. The water composition and environmental conditions are based on the results of in-package chemistry and in-drift chemistry studies. Field observations, laboratory measurements, and thermodynamic and kinetic considerations are utilized to ensure the resulting solubilities are conservative. Fourteen radioelements have been studied (U, Np, Pu, Th, Am, Ac, Tc, I, C, Cs, Sr, Ra, Pa, and Pb) and their solubilities are presented as either functions of environmental conditions or statistical distributions. An alternative source term model for Np, which was based on measurements of spent fuel dissolution experiments rather than conventional thermodynamic considerations, was also developed. Comparison of it with the Np base case solubility model suggests that it is necessary to advance our understanding about the behaviors of Np during the process of spent fuel corrosion.
Structural Alterations in Titanate Pyrochlores Induced by Ion Irradiation: Xray Photoelectron Spectrum Interpretation
Authors: Chen J. , Lian J. , Wang L. M. , Ewing R. C. , Farmer J. Matt , Boatner L. A. 
Published: April 2011

ABSTRACTTitanate pyrochlores are candidate host materials for the disposition of plutonium from dismantled nuclear weapons. These pyrochlores also have potential applications as solid electrolytes and oxygen gas sensors. The radiation-induced microstructural evolution of titanate pyrochlores has been characterized using x-ray photoelectron spectroscopy (XPS). XPS analysis of the Ti 2p and O 1s binding energy shifts of REE2Ti2O7 (REE: rare earth) surface layers before and after irradiation shows that the primary manifestations of amorphization are distortions or changes in the coordination number of the titanium polyhedra. A model based on glass network structure was developed, and predictions of the relative susceptibilities for amorphization of the titanate pyrochlores are obtained that are consistent with the experimental results.
Heavy Ion Irradiation of Zirconate Pyrochlores
Authors: Lian J. , Wang L. M. , Chen J. , Ewing R. C. , Kutty K. V. G. 
Published: April 2011

ABSTRACTZirconate pyrochlores, A2Zr2O7, are important potential nuclear waste forms for Puimmobilization. The binary Gd2(Ti2-xZrx)O7 has been shown to have increasing resistance to ionirradiation damage with the increasing Zr content, and Gd2Zr2O7 is radiation resistant to a 1 MeV Kr+ ion irradiation at 25 K to a dose of 5 dpa. In this study, a 1.5 MeV Xe+ irradiation was completed for zirconate pyrochlores A2Zr2O7 (A=La, Nd, Sm, Gd). The radiation resistance decreases with an increase of the ionic radius of A-site cation. La2Zr2O7 is the first zirconate pyrochlore to be amorphized by ion beam irradiation, and the critical amorphization temperature, Tc, is ∼310 K. The susceptibility of La2Zr2O7 to ion beam damage is related to its structure, which shows the largest deviation from the ideal fluorite structure. These results are also consistent with calculations of the cation antisite formation energy in the pyrochlore structure. The ion irradiation-induced pyrochlore-to-fluorite transformation occurred in all of the irradiated zirconate pyrochlore phases. Based on the results for Gd2Ti2-xZrxO7 and A2Zr2O7, the defect fluorite structures are stable when the ionic radii ratio rA/rB≤1.54; beyond this limit, the defect fluorite structure becomes increasingly unstable relative to the amorphous state.
Porous Crystalline Silica (Gubka) as a Inorganic Support Matrix for Novel Sorbents
Authors: Tranter T. J. , Aloy A. S. , Sapozhnikova N. V. , Knecht D. A. , Todd T. A. 
Published: April 2011

ABSTRACTInorganic ion exchange media typically exist as fine powders, making large-scale use impractical, unless the media can be affixed to an appropriate matrix. Likewise, organic chelating agents are typically dissolved in a solvent and absorbed into porous matrices for use in extraction chromatography. The most common matrices utilized in both cases are organic materials, that are not compatible with high radiation fields or acceptable as final waste forms. Recent investigations have shown that ion exchange sorbents can be effectively loaded within a porous crystalline silica (Gubka) matrix. This approach allows for target radionuclides to be adsorbed into a porous micro-crystalline glass matrix which encapsulates the contaminant and becomes the final waste form. Subsequent to adsorption of the radionuclides, the Gubka matrix can be compressed in a hot uniaxial press, resulting in an even greater volume reduction. The porous glass matrix is produced in Russia using fly ash residue from coal combustion power generating plants. It consists of consolidated arrays of hollow glass cenospheres and is termed Gubka which is the Russian word for sponge. This paper describes results of a collaborative research program between the Khlopin Radium Institute, St.Petersburg, Russia, the Institute of Chemistry and Chemical Technologies, Krasnoyarsk, Russia, the Mining and Chemical Combine, Zheleznogorsk, Russia, and the Idaho National Engineering and Environmental Laboratory. Ammonium molybdophosphate (AMP) for the removal of cesium from acidic liquid waste has been successfully incorporated into Gubka matrices. Test results for cesium removal, using AMP-Gubka, are discussed.
Chemical Interactions of UOP IONSIV IE-911 (CST) with SRS Waste Simulants
Authors: Nyman May , Krumhansl James L. , Jove-Colon Carlos , Zhang Pengchu , Nenoff Tina M. , Headley Thomas J. , Su Yali , Li Liyu 
Published: April 2011

ABSTRACTIE-911 is a bound form of cystalline silicotitanate (CST) that was extensively tested for removing 137Cs from the Savannah River Site (SRS) tank wastes. In some simulant tests, column plugging incidents were observed, which led to thorough investigations to determine the causes and to develop protocols to avoid future plugging incidents. A related problem was the apparent decrease in Cs scavenging capability in some long-term tests. Our studies revealed that the interaction of IE-911 with the highly basic, high ionic strength, SRS average salt simulant could result in precipitation of; 1) poorly crystalline Nb-oxide, or 2) aluminosilicate zeolitic phases. The source for the Nb-oxide precipitate was determined to be a minor impurity phase that is a byproduct of CST manufacturing. The mechanisms of dissolution and re-precipitation of this phase in column pretreatment solution were investigated, and a protocol to rid IE-911 of this impurity was devised. The source material for the aluminosilicate zeolite precipitate was determined to be predominantly from the waste solution rather than the IE-911. Solubility experiments coupled with a thermodynamic analysis provided a protocol to predict when aluminosilicate precipitation will and will not occur. Finally, it was also established that aluminosilicate precipitation on the surfaces of the IE-911 granules could also account for an apparent decrease in equilibrium Kd and decrease in kinetics of Cs sorption.
Assessment of the Evolution with Time of the Instant Release Fraction of Spent Nuclear Fuel in Geological Disposal Conditions
Authors: Poinssot Christophe , Lovera Patrick , Faure Marie-Hélène 
Published: April 2011

ABSTRACTUnder the geological disposal conditions, spent nuclear fuel (SNF) is expected to evolve during the first thousands years while being maintained isolated from the biosphere before water comes in. Under those circumstances, several driving forces would lead to the progressive intrinsic SNF transformations within the rod which would basically modify the physical and chemical state of the fuel and the subsequent release of radionuclides in solution. In this paper, we briefly summarize the mechanisms we estimate to be significant and propose a new framework for the quantitative assessment of the radionuclide (RN) inventory we estimate to be associated to the classically referred to “Instant Release Fraction” (IRF). We hence demonstrate that in this framework, significantly high IRF values have to be expected for the long term due mainly to the presence of athermal diffusion processes.
Alteration of a Zirconolite Glass-Ceramic Matrix under Hydrothermal Conditions
Authors: Martin Christelle , Ribet Isabelle , Advocat Thierry 
Published: April 2011

ABSTRACTGlass-ceramic matrices based on zirconolite (CaZrTi2O7) are being considered for specific conditioning of plutonium or the minor actinides. The actinides are distributed throughout the zirconolite crystals and the residual glass phase. Since zirconolite alteration is extremely limited, however, actinide release from the glass-ceramic material is mainly attributable to alteration of the residual glass. Zirconolite glass-ceramic specimens and specimens corresponding to the residual glass phase alone were therefore altered under hydrothermal conditions (150°C) and under initial rate conditions (100°C) to compare their kinetic behavior and estimate the effect of the crystals on material alteration. Under hydrothermal conditions, alteration occurred during the first few days: SEM observations showed greater alteration of the glass-ceramic material due to a phenomenon of preferential glass alteration around the zirconolite crystals; after three days the alteration rate had considerably diminished and both specimens exhibited similar behavior. Under initial rate conditions the initial rates differed due to a variation in the reactive surface area of the glass-ceramic.
Low-Temperature Mobility of Rare Earth Elements (REE), U, and Th at the Olkiluoto Site, SW Finland
Authors: Marcos Nuria 
Published: April 2011

ABSTRACTThis work is a first effort to link hydrogeological measurements to structural modeling by using the mobility of rare earth element (REE), U, and Th at the Olkiluoto site. REE, U and Th concentrations were measured in 5 groundwater samples located at depths varying between 132 and 446 m in three drill holes at the Olkiluoto site. The pH of groundwater samples are all about 8 and Eh(Pt) varies from –50 to –200 mV. Also the REE, U and Th concentrations of rock samples collected from core sections in the vicinity of water conducting fractures were measured to examine rock-water interactions in the system. The rock samples were cut into slices parallel to the fracture surface. An aliquot of each slice was leached with 0.5 N acid nitric to examine the readily leachable REE, U and Th fraction of each slice. The groundwater samples were normalized to each of the analyzed rock samples. Although the REE concentrations of the water samples are overall depleted in all the REEs compared to the rocks and leachates, and whole REE spectra could not be obtained for any of the groundwater samples, enrichment in the intermediate REE (IREE) with respect to the light REE (LREE) is observed.An increasing loss of REE and U from rock matrix towards fracture surface is observed in samples at depths of 141, 159, and 466 m. Loss of U is also observed in a sample at about 246 m depth. Loss of Th is only observed at the depths of 159 and 246 m. The loss of U (readily leachable fraction) in the rock samples was found to be linked to the hydraulic conductivity in the related water-conducting fractures.
Natural Colloids in Groundwater from a Bentonite Mine- Correlation between Colloid Generation and Groundwater Chemistry -
Authors: Kuno Yoshio , Kamei Gento , Ohtani Hiroyuki 
Published: April 2011

ABSTRACTColloids, mainly montmorillonite, generated by erosion of compacted bentonite by groundwater flow might enhance the transport of radionuclides from a radioactive waste repository. The influence of aqueous chemistry (i.e. pH, cation concentration and valence) on the dispersion of montmorillonite colloid was studied. Colloids were flocculated under higher cation concentrations ([Na+] > 10−2 M, [Ca2+] > 10−3 M) and/or under acidic condition (pH = 4) by means of batch-type experiments. Derjaguin-Landau-Verwey-Overbeek (DLVO) theory was applied to estimate the stability of colloidal dispersion and then the limitation of theoretical calculations was pointed out. Groundwater samples were collected from two galleries at different depths of the Tsukinuno bentonite mine (northern Honshu, Japan) and investigated for the populations of colloids. The groundwater flows vertically through Tertiary sedimentary argillaceous rocks and fine tuff beds which are mined for bentonite. Low colloid concentrations were measured in these groundwater samples. This result suggests that the colloids cannot significantly disperse in the groundwaters under higher cation concentration ([Na+] > 10−2 M) or under acidic conditions. This result is consistent with those of the batch-type experiments.
DNA Templating of Ethylene-Oxide-Coated Nanoclusters
Authors: Jhaveri S. , Foos E. E. , Ancona M. G. , Snow A. W. , Twigg M. E. , Chang E. , Pilobello K. , Goldman E. , Lowy D. 
Published: April 2011

ABSTRACTUsing gel electrophoresis we demonstrate the attachment of short ssDNAs to a new type of water-soluble gold nanocluster that is encapsulated with ethylene oxide ligands. Initial experiments indicate that these DNA/nanocluster conjugates can subsequently be hybridized to a longer DNA template suggesting a pathway for nanofabrication of multi-cluster assemblies.
Fabrication and Application of Protein Crystal Microarrays
Authors: Hosokawa Yoichiroh , Matsumura Satoshi , Yoshikawa Hiroshi Y. , Masuhara Hiroshi , Nakamura Ryosuke , Kanematsu Yasuo , Ikeda Keiko , Shimo-oka Ai , Mori Hajime 
Published: April 2011

ABSTRACTWith the aim of fabricating highly integrated protein microarrays, functional proteins were occluded into a protein crystal, consisting of a proteinaceous occlusion body termed polyhedrin, and the crystals were individually fixed onto a polymer film by using laser trapping and bonding techniques. Individual crystals were trapped by the 1064 nm beam of a Nd3+:YAG laser and placed to the film. The bonding to the film was achieved by irradiating with the single shot of the 800 nm beam of a femtosecond Ti:sapphire laser. Enhanced green fluorescent protein (EGFP) was occluded into the polyhedrin crystal and the crystals were patterned and observed by florescence imaging and single crystal florescence spectroscopy. From these experiments, the biological activity of the bonded crystal was confirmed and their potential as element in protein microarrays was discussed.
Manufacturing and Performance Assessments of Several Applications of Electrotextiles and Large-Area Flexible Circuits
Authors: Cadogan David P. , Shook Lauren S. 
Published: April 2011

ABSTRACTNumerous applications of electrotextiles and flexible circuits have been identified that can advance systems performance for many commercial, military, and aerospace devices. Several novel uses of electrotextiles have been developed for lab testing, while others have been utilized in products on the commercial market, as well as items that have flown in space. ILC Dover, Inc. has utilized conductive fibers in various inflatable and tensile structures for signal transmission and electrostatic charge protection. Conductive and pressure sensitive textiles have been incorporated in the advanced development space suit (I-Suit) as switch controls for lights and rovers, and as signal transmission cables. Conductive fibers have been used in several stitched applications for electrostatic charge dissipation. These applications include large pharmaceutical containment enclosures where fine potent powders are being captured for transfer between manufacturing facilities, as well as impact attenuation airbags used in landing spacecraft on the surface of Mars. In both cases, conductive threads are uniquely located in seams and panel locations to gather and direct charge through surface fibers and panel interconnects. Conductive fibers have also been utilized in a conformal Sensate Liner garment for the identification of wound locations and medical sensor signal transmission for soldier health monitoring while on the battlefield. The performance challenges of these structures require a careful, systematic application of electrotextiles because of the flexing, straining, and exposure of the materials to harsh environments. ILC has also been developing “gossamer” spacecraft components utilizing unique materials and multi-functional structures to achieve extremely low mass and low launch volumes. Examples of large deployable structures featuring very thin, large flexible circuits for use in space include synthetic aperture radar (SAR) antennas, communications antenna reflectarrays, and active variable reflectance solar sails. Design and materials challenges of electrotextile and large-area flexible circuit membrane structures as demonstrated in engineered applications will be discussed in this paper.
Tailored Nanofiber Morphologies Using Modulated Electrospinning for Biomedical Applications
Authors: Lin David Y. , Johnson Michael A. , Vohden Richard A. , Chen Deborah , Martin David C. 
Published: April 2011

ABSTRACTThe process of electrostatic fiber formation, or electrospinning, was used to generate polymer filaments with diameters in the 50–200 nm range. We have shown that in addition to process parameters such as solution concentration, spinning voltage, and deposition distance, an oscillating electric field can also influence the morphology of the electrospun nanofibers. Specifically, effects of the oscillating field strength and frequency, spinning voltage, and deposition distance on fiber diameter as well as size and number density of the beaded structures in the fibrous thin films are examined.The results of our study demonstrate that modulated field potential produces more uniform fibers. Increasing either the oscillating field strength or frequency yields more uniform average fiber diameter. Also, for systems with the “beads on a string” fiber morphology, increasing the oscillating field strength produces more uniform bead sizes.The ability to tailor fiber morphology using an oscillating electric field has promising implications in a wide range of applications including controlled-release drug delivery systems and biocompatible implants. We show here the potential of using electrospun nanofibers as a porous template for growing fuzzy conductive polymers to modify the surface of a neural recording microelectrode device. These hairy nanostructures can increase signal transport and mediate the mechanical property differences between the device and the soft brain tissues.