bluuebunny/crossref_metadata_2025_split huggingface dataset:
Immobilized Low-Activity Waste Performance Assessment:2001 Version
Authors: Manna Frederick M. , Puighb Raymond J. , Finfrockb S.H. , Khaleelb R. , Baconc D.H. , Bergeronc M.P. , McGrailc B.P. , Wurstnerc S.K. 
Published: April 2011

ABSTRACTThe Hanford Immobilized Low-Activity Waste Performance Assessment[1] examines the longterm environmental and human health effects associated with the planned disposal of the vitrified low-activity fraction of waste presently contained in Hanford Site tanks. The tank waste is the byproduct of separating special nuclear materials from irradiated nuclear fuels over the past 50 years. This waste is stored in underground single- and double-shell tanks. The tank waste is to be retrieved, separated into low-activity and high-level fractions, and then immobilized by vitrification. The U.S. Department of Energy (DOE) plans to dispose of the low-activity fraction in the Hanford Site 200 East Area. The high-level fraction will be stored at the Hanford Site until a national repository is approved.This report provides the site-specific long-term environmental information needed by the DOE to modify the current Disposal Authorization Statement for the Hanford Site[2]. The original Disposition Authorization Statement was based on the 1998 version[3] of this performance assessment, which was conditionally accepted by DOE [4].The calculations in this performance assessment show that a “reasonable expectation” exists that the disposal of the immobilized low-level fraction of tank waste from the Hanford Site can meet environmental and health performance objectives. As shown by the sensitivity studies, this conclusion remains valid despite the conceptual designs of the disposal facility and the ILAW packaging having undergone changes.
Characterisation of the Barrier Performance of Cements
Authors: Glasser F. P. 
Published: April 2011

ABSTRACTPortland and modified Portland cements are useful matrices for solidification and storage of wastes. Concrete containing cement is likely to be introduced into the repository. The further use of cement as an engineered barrier reduces materials incompatibility problems. Cement has a high internal pH and maintains a high buffering reserve of alkalinity. This in turn, reduces the solubility of many radionuclides. The source of the immobilisation (chemical, physical) is sensitive to nuclide species: sorption and precipitation are the main binding mechanisms. The conditioning action of cement could affect the performance of other engineered barriers. The deterioration of cements is discussed. Areas of research needs are highlighted.
Laser-Induced Photochemical Surface Modification of Intraocular Lens for Blocking After-Cataract
Authors: Tanizawa Katsuya , Murahara Masataka 
Published: April 2011

ABSTRACTThe central part of polymethylmethacrylate (PMMA) lens was modified to be hydrophobic and the peripheral part, to be hydrophilic by photochemical reaction with ArF excimer laser and chemicals. PMMA has a high–transmittance property in the visible light and has been used as an intraocular lens. However, protein and fat are stuck onto the lens surface after a long-term insertion, which makes the surface get opaque; that is the after-cataract.Accordingly, the central part of the lens was modified to be hydrophobic in order to protect the PMMA lens from fat and protein. And, the peripheral part was modified to be hydrophilic to develop an affinity for the tissue. Firstly, the central part of the lens was irradiated with ArF laser (147kcal/mol) in the presence of fluorine oil (perfluoropolyether) or CFn gas ambience. By this photochemical reaction, the CF3 functional group was substituted on the PMMA surface. Secondly, the peripheral part of the lens was irradiated with ArF laser (147kcal/mol) in the presence of water. By this photochemical reaction, the OH functional group was substituted on the PMMA.The contact angle with the physiological salt solution was measured. The contact angle of the non-treatment sample was 83 degrees. The one treated with perfluoropolyether was 117 degrees at the laser shot number of 5000 and the laser fluence of 25 mJ/cm2. When using CBrF3 and CClF 3, the contact angles were both 91 degrees at the laser shot number of 5 and the laser fluence of 20 mJ/cm2. And, the one using the water was 14 degrees, less than the contact angle of the non-treatment sample.It was confirmed that the exposure part of the PMMA surface with the laser was modified into hydrophobic or hydrophilic by the existence of oil and water. In conclusion, our study successfully demonstrated the production of the ideal intraocular lens.
Simulation of chiral liquid crystal self-assembly: analogies with the structural formation of biological fibrous composites
Authors: Luca Gino De , Rey Alejandro D. 
Published: April 2011

ABSTRACTThe wide majority of biological fibrous composites exhibit twisted plywood architectures (planar or cylindrical) for mechanical reasons [1–5]. These supramolecular organizations originate from the passage of the extracellular matrix (surrounding the chiral fibrous molecules) trough a lyotropic cholesteric liquid crystalline mesophase during the structure formation process [1–5]. In this work, we used the well-established Landau-de Gennes theory of liquid crystals in order to develop a fundamental understanding of the supramolecular self-assembly process leading to the planar monodomain (defect-free) twisted plywood architecture [6]. Simulations illustrate the importance of constraining surface in the formation of defect-free (mechanically effective) composites. These results provide a better understanding of tissue morphogenesis which is highly desirable for the development of new bio-inspired synthetic composites.
Amorphous Silicon Thin Film Transistors on Kapton Fibers
Authors: Bonderover Eitan , Wagner Sigurd , Suo Zhigang 
Published: April 2011

ABSTRACTThe textile industry uses weaving to create very large quantities of fabric very quickly. The goal of our research is to use this well established technology to create complex large-area circuits quickly and efficiently. In our laboratory we have previously shown that amorphous silicon (a-Si) can be used to make thin-Film transistors (TFTs) on Kapton (a highly temperature-resistant polyimide from DuPont). We also previously showed that these TFTs can survive mechanical loads. A process has been designed to make “TFT fibers” by fabricating a-Si TFTs on Kapton. A special TFT geometry has also been developed. The structure consists of 3 large gold contact pads – one for each terminal of the TFT – running along the fiber. These contact pads allow connections to be made between TFT fibers using conductor fibers – Kapton fibers coated only with gold. The TFT fabrication process is based on a low temperature (150°C) Plasma Enhanced Chemical Vapor Deposition (PECVD) process. The TFTs are fabricated on a Kapton sheet from which flat fibers are made by the slit film technique. So far the best method for cutting a Kapton sheet into fibers has been plasma etching. We will describe the electronic characteristics of these TFTs as well as the electrical characteristics of the contacts between TFT fibers.
Preparation and Characterization of Nanometer-scale Polycarbonate Fibers: Bead Formation
Authors: Shawon Jamila , Sung Changmo 
Published: April 2011

ABSTRACTElectrospinning is a superior process compared to other conventional spinning methods for the production of fibers in the sub-micron to nanometer scales. Such fiber membranes have exceptionally large surface areas and small pore sizes. The process requires an electrostatic force, which induces charges on the liquid droplet of the polymer solution or melts and therefore overcomes the surface tension and viscoelasticity forces to create an electrically charged jet. When the jet dries or solidifies, an electrically charged fiber remains, which can be directed or accelerated by the electrical forces and then collected in non-woven fiber membrane or other useful shapes. The present research work demonstrates the electrospinning of polycarbonate solution with solvent mixtures THF (Tetrahydrofuran) and DMF (Di-methyl formamide) to produce nanometer scale polycarbonate fibers. The solvent mixture of THF and DMF was the major parameter for producing nano-polycarbonate fibers along with the formation of byproducts beads. The electrostatic voltage, viscosity and surface tension also showed significant effect on bead formation and bead density. The microstructures of the polycarbonate beads were quantitvely investigated by Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM).
Electrotextiles - Present and Future
Authors: Natarajan Karthikeyan , Dhawan Anuj , Seyam Abdelfattah M. , Ghosh Tushar K. , Muth John F. 
Published: April 2011

ABSTRACTElectrotextiles have attracted increasing attention in recent years. The combinations of textile structures that are lightweight, flexible, conformable, and strong, with electronics have aroused keen interest from many disciplines. With technological innovations appearing in both textile and electronics, integration of these has started giving benefits. Innovations like the sensate liner, soft switches and smart composites have found many applications in sports, healthcare, military, aerospace engineering, civil engineering and many other fields. The purpose of this paper is to provide an overview of various electrotextile products available and explain their functionality. Additionally, the paper provides a review of future electrotextile products, which are in the developmental phase, and the challenges that need to be addressed by researchers and industry.
Thin-Film Solid-State Lithium Battery for Body Worn Electronics
Authors: McDermott Joseph , Brantner Paul C. 
Published: April 2011

ABSTRACTInfinite Power Solutions manufactures a flexible rechargeable micro ampere-hour solidstate battery based on thin-film Lithium technology where the battery can be engineered into the product for life as a cost effective solution with “the battery that never needs to be replaced”. The performance characteristics of the battery combined with low power electronic textile applications will require “A Different Way of Thinking About Batteries” relative to battery management and innovative methods of recharging the battery (such as charging the battery whenever the materials are washed and dryed). This paper will review the characteristics of the battery specifically in relation to power generation for flexible electronic materials and the integration issues for a thin-film battery for flexible electronic materials.
Synthesis of Semi-Conducting Nanoparticles within a Protein Template
Authors: Wong Kim K. W. , Mayes Eric L. 
Published: April 2011

ABSTRACTThe ability to synthesise and tune photoresponsive and photoredox II-VI semi-conductor nanoparticles by quantum confinement is a continuously and rapidly developing area. Chemical methods are useful in producing dispersions of nanoparticles of uniform size in many organic solvents. Such synthetic methods employ the use of reverse micelles [1,2], phospholipid vesicles[3,4] or capping agents[5,6]to restrict particle size and growth to the nanometre regime.The production of super lattice assemblies, through, for example the use of controlled crystallisation [7], Langmuir monolayers[8], Langmuir Blogget films[9], and self assembled short chain dithiol monolayers[10] on gold substrates has also received attention in the past. This latter approach potentially opens the way for self assembled electro-luminescent devices[11].The ability to couple organic self assembly and inorganic nano-synthesis could also provide a route toward the chemical synthesis of an organised array of quantum-confined semiconductors. An aspect of this synthesis with construction approach is the possible coupling of biological templating systems to produce biomimetic materials [12,13]. In fact, an example would be the stabilised CdS nanoparticles in yeast binding to phytochelatin peptides which are secreted in response to metal toxicification [14].
The Role of Nanoscale Silicon in Optical Interconnects
Authors: Fauchet Philippe M. 
Published: April 2011

ABSTRACTThe semiconductor industry association roadmap has identified interconnects as a major barrier to progress starting in 2010. Optical interconnects (OI) offer an attractive solution for chip-to-chip communications, however there is no general agreement on how to design them. Eventually, OI may also perform a large amount of intra-chip clocking and signaling, which implies that any chip-to-chip OI system must be designed to be compatible with intra-chip OI, from the points of view of manufacturability, architecture, and device design. We are exploring the use of nanoscale silicon for OI. This paper reports progress toward the demonstration of two basic building blocks of an OI system, namely a Si laser and a Si-based modulator.
Polymorphous silicon nanowires synthesized by plasma-enhanced chemical vapor deposition
Authors: Zeng X.B. , Liao X.B. , Diao H.W. , Hu Z.H. , Xu Y.Y. , Zhang S.B. , Chen C.Y. , Chen W.D. , Kong G.L. 
Published: April 2011

ABSTRACTPolymorphous Si nanowires (SiNWS) have been successfully synthesized on Si wafer by plasma enhanced chemical vapor deposition (PECVD) at 440°C, using silane as the Si source and Au as the catalyst. To grow the polymorphous SiNWS preannealing the Si substrate with Au film at 1100 °C is needed. The diameters of Si nanowires range from 15 to 100 nm. The structure, morphology and chemical composition of the SiNWS have been characterized by high resolution x-ray diffraction, scanning electron microscopy, transmission electron microscopy, as well as energy dispersive x-ray spectroscopy. A few interesting nanowires with Au nanoclusters uniformly distributed in the body of the wire were also produced by this technique.
Fabrication of Ordered Metallic Nanocluster Arrays Using a Focused Ion Beam
Authors: McMahon Matthew D. , Hmelo Anthony B. , Lopez Rene , Ryle Wesley T. , Newton Allen T. , Haglund Richard F. , Feldman Leonard C. , Weller Robert A. , Magruder Robert H. 
Published: April 2011

ABSTRACTWe have fabricated ordered arrays of gold nanocrystals on FIB-processed silicon substrates using electroless deposition. We have also fabricated ordered arrays of silver nanocrystals on silicon with diameters 40–60 nm separated by 180 nm center-to-center, using pulsed-laser deposition (PLD) to deposit silver on the substrate. The metal nanocrystal arrays are characterized using SEM as well as AFM and energy dispersive x-ray (EDX) analysis. AFM confirms particle sizes measured in SEM, and EDX analysis demonstrates that Ag preferentially clusters at sites that have been damaged by the ion beam. These results suggest that the FIB-PLD combination can be used to create ordered arrays of Ag nanocrystals with diameters of 10 nm or less.
Proton Induced Structuring of a Photostructurable Glass
Authors: Abraham Meg , Gomez-Morilla Inmaculada , Marsh Mike , Grime Geoff 
Published: April 2011

ABSTRACTThe use of photons to create intricate three-dimensional and buried structures [1] in photo-structurable glass has been well demonstrated at several institutions [2]. In these instances the glass used whether it be Foturan™, made by the Schott Group or a similar product made by Corning Glass, forms a silver nucleation sites on exposure to intense UV laser light via a two-photon process. Subsequent annealing causes a localized crystal growth to form a meta-silicate phase which can be etched in dilute hydrofluoric acid at rates of 20 to 50 times that of the unprocessed glass. The same formulation of glass can be “exposed” using a particle beam to create the nucleation site. In the case of particle beam exposure, experiments have shown that the mechanisms that cause this initial nucleation and eventual stochiometric transformation, after annealing, depend largely on the beam energy.
DFB Structures in Electroactive Conjugated Polymers realized by Soft Lithography
Authors: Moderegger Erik , Gaal Martin , Gadermaier Christoph , Plank Harald , List Emil J.W. , Pogantsch Alexander , Güntner Roland , Scherf Ullrich , Leising Günther 
Published: April 2011

ABSTRACTThe realization of a polymeric injection laser diode is an important aim in organic electronics. A crucial step towards this goal lies in the understanding and fabrication of feedback structures for lasers. Such feedback structures may be fabricated either in the substrate or directly in the active polymer layer.Soft Lithography has proven itself as a useful tool to pattern a wide variety of materials. Typically one uses elastomeric molds (stamps) to pattern materials and structures whereby dimensions as low as 30 nm can be achieved.Different types of Soft Lithographic processes are applied to produce optical feedback structures for optically pumped laser arrays.
Influence of low-energy electron beam irradiation on defects in activated Mg-doped GaN
Authors: Gelhausen O. , Phillips M. R. , Klein H. N. , Goldys E. M. 
Published: April 2011

ABSTRACTCL spectroscopy studies at varying temperatures and excitation power densities as well as depth-resolved CL imaging were conducted to investigate the impact of low energy electron beam irradiation (LEEBI) on native defects and residual impurities in metal-organic vapor phase epitaxy (MOVPE) grown Mg-doped p-type GaN. Due to the dissociation of (Mg-H)0 complexes, LEEBI significantly increases the (e,Mg0) emission (3.26 eV) at 300 K and substantially decreases the H-Mg donor-acceptor-pair (DAP) emission (3.27 eV) at 80 K. In-plane and depth-resolved CL imaging indicates that hydrogen dissociation results from electron-hole recombination at H-defect complexes rather than heating by the electron beam. The dissociated hydrogen atoms associate with nitrogen vacancies, forming a deeper donor, i.e. a (H-VN) complex. The corresponding deeper DAP emission with Mg centered at 3.1 eV is clearly observed between 160 and 220 K. Moreover, a broad yellow luminescence (YL) band centered at 2.2 eV is observed in MOVPE-grown Mg-doped GaN after LEEBI-treatment. It is suggested that a combination of LEEBI-induced Fermi-level downshift due to Mg-acceptor activation and simultaneous dissociation of gallium vacancy-impurity complexes, i.e. (VGa-H), is responsible for the observed YL.
ZnO and ZnMgO Growth by Molecular Beam Epitaxy
Authors: Yano Mitsuaki , Ogata Ken-ichi , Yan FengPing , Koike Kazuto , Sasa Shigehiko , Inoue Masataka 
Published: April 2011

ABSTRACTCharacteristics of the ZnO and ZnMgO films grown by radical-source molecular beam epitaxy are reported. The ZnO films on a-plane sapphire substrates had a superior quality in crystallographic, optical and electrical properties, and n-type doping with Al was successfully performed up to 1020 cm–3. The Mg-content of ZnMgO alloys was found to be controlled by a simple growth mechanism as a function of Mg-cell temperature. The alloying in the ZnO-rich region resulted in single-crystalline growth although the photoluminescence characteristics at x = 0.22 suggested the presence of microscopic phase separation. Single-crystalline growth was also achieved on Si (111) substrates by using a CaF2 buffer layer to protect the Si-surface from oxidation.
Effect of Remote Hydrogen Plasma Treatment on ZnO Single Crystal Surfaces
Authors: Strzhemechny Yuri M. , Nemergut John , Bae Junjik , Look David C. , Brillson Leonard J. 
Published: April 2011

ABSTRACTWe have studied the effects of hydrogen plasma treatment on the defect characteristics in single crystal ZnO grown at Eagle-Picher by chemical vapor transport. Depth-dependent cathodoluminescence (CL) spectra, temperature-dependent (9–300 K) and excitation intensity-dependent photoluminescence (PL) spectra reveal significant changes resulting from unannealed exposure of n-type ZnO to a remote hydrogen plasma. Low temperature PL spectra show that this hydrogen exposure effectively suppresses the free-exciton transition and redistributes intensities in the bound-exciton line set and two-electron satellites with their phonon replicas. The resultant spectra after hydrogenation exhibit a new peak feature at 3.366 eV possibly related to a neutral donor bound exciton. A simple thermal analysis of the activation energy for the 3.366 eV line yields 5–10 meV. Hydrogenation also produces a violet 100 meV-wide peak centered at 3.16 eV. Remote plasma hydrogenation produces similar changes in room-temperature CL spectra: near-band edge emission intensity increases with hydrogenation. Furthermore, this new emission increases with proximity to the free ZnO surfaces, i.e., with decreasing the energy of the incident electron beam from 3.0 down to 0.5 keV. Subsequent annealing at 450 °C completely restores both the PL and CL spectra in the sub-band gap range. The appearance of a new bound-exciton feature at 3.366 eV with H plasma exposure, the near-surface nature of the spectral changes, and the reversibility of spectral features with annealing indicate a direct link between H indiffusion and appearance of a shallow donor.
Far-infrared magnetooptical generalized ellipsometry determination of free-carrier parameters in semiconductor thin film structures
Authors: Hofmann Tino , Grundmann Marius , Herzinger Craig M. , Schubert Mathias , Grill Wolfgang 
Published: April 2011

ABSTRACTIn accord with the Drude model, the free-carrier contribution to the dielectric function at infrared wavelengths is proportional to the ratio of the free-carrier concentration N and the effective mass m*, and the product of the optical mobility μ and m*. Typical infrared optical experiments are therefore sensitive to the free-carrier mass, but determination of m* from the measured dielectric function requires an independent experiment, such as an electrical Hall-effect measurement, which provides either N or μ. Highly-doped zincblende III-V-semiconductors exposed to a strong external magnetic field exhibit non-symmetric magnetooptical birefringence, which is inversely proportional to m*. If the spectral dependence of the magnetooptical dielectric function tensor is known, the parameters N, m* and μ can be determined independently from optical measurements alone. Generalized ellipsometry measures three complex-valued ratios of normalized Jones matrix elements, from which the individual tensor elements of the dielectric function of arbitrarily anisotropic materials in layered samples can be reconstructed. We present the application of generalized ellipsometry to semiconductor layer structures at far-infrared wavelengths, and determine the magnetooptical dielectric function for n-GaAs and n-AlGaInP for wavelengths from 100 μm to 15 μm. We obtain the effective electron mass and mobility results of GaAs in excellent agreement with results obtained from Hall-effect and Shubnikov-de-Haas experiments. The effective electron mass in disordered n-AlGaInP obtained here is in very good agreement with previous k·p calculations. (Far)-infrared magnetooptic generalized ellipsometry may open up new avenues for non-destructive characterization of free-carrier properties in complex semiconductor heterostructures.
MOCVD Growth and Characterization of InNAs/GaAs Quantum Wells
Authors: El-Emawy Abdel-Rahman A. , Nuntawong Noppadon , Cao Hongjun , Liu Chiyu , Xu Huifang , Osiński Marek 
Published: April 2011

ABSTRACTInNAs/GaAs multiple-quantum-wells were grown by MOCVD on (100) SI-GaAs substrates using trimethylindium, tertiarybutylarsine, and 95–97.5% of dimethylhydrazine (DMHy) in the vapor phase. The crystalline quality and solid phase composition were evaluated using highresolution x-ray diffraction analysis. Nitrogen content in InNAs wells was determined to be 28%. Electron energy loss spectroscopy was used to confirm the presence of nitrogen in quantum wells. Surface morphology was investigated by atomic force microscopy (AFM) and field emission microscopy (FEM).