Sample records for transfer electronic transmission

  1. Ponderomotive phase plate for transmission electron microscopes

    DOE Patents [OSTI]

    Reed, Bryan W. (Livermore, CA)

    2012-07-10T23:59:59.000Z

    A ponderomotive phase plate system and method for controllably producing highly tunable phase contrast transfer functions in a transmission electron microscope (TEM) for high resolution and biological phase contrast imaging. The system and method includes a laser source and a beam transport system to produce a focused laser crossover as a phase plate, so that a ponderomotive potential of the focused laser crossover produces a scattering-angle-dependent phase shift in the electrons of the post-sample electron beam corresponding to a desired phase contrast transfer function.

  2. Scanning Transmission Electron Microscopy for Nanostructure

    E-Print Network [OSTI]

    Pennycook, Steve

    152 6 Scanning Transmission Electron Microscopy for Nanostructure Characterization S. J. Pennycook. Introduction The scanning transmission electron microscope (STEM) is an invaluable tool atom. The STEM works on the same principle as the normal scanning electron microscope (SEM), by forming

  3. Scanning/Transmission Electron Microscopes

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOnItemResearch > TheNuclearHomeland andEffectsScanning/Transmission Electron Microscopes

  4. In Situ Electrochemical Transmission Electron Microscopy for...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    for Battery Research. Abstract: The recent development of in situ liquid stages for (scanning) transmission electron microscopes now makes it possible for us to study the details...

  5. Proton-Coupled Electron Transfer

    SciTech Connect (OSTI)

    Weinberg, Dave; Gagliardi, Christopher J.; Hull, Jonathan F; Murphy, Christine Fecenko; Kent, Caleb A.; Westlake, Brittany C.; Paul, Amit; Ess, Daniel H; McCafferty, Dewey Granville; Meyer, Thomas J

    2012-01-01T23:59:59.000Z

    Proton-Coupled Electron Transfer (PCET) describes reactions in which there is a change in both electron and proton content between reactants and products. It originates from the influence of changes in electron content on acid?base properties and provides a molecular-level basis for energy transduction between proton transfer and electron transfer. Coupled electron?proton transfer or EPT is defined as an elementary step in which electrons and protons transfer from different orbitals on the donor to different orbitals on the acceptor. There is (usually) a clear distinction between EPT and H-atom transfer (HAT) or hydride transfer, in which the transferring electrons and proton come from the same bond. Hybrid mechanisms exist in which the elementary steps are different for the reaction partners. EPT pathways such as PhO•/PhOH exchange have much in common with HAT pathways in that electronic coupling is significant, comparable to the reorganization energy with H{sub DA} ~ ?. Multiple-Site Electron?Proton Transfer (MS-EPT) is an elementary step in which an electron?proton donor transfers electrons and protons to different acceptors, or an electron?proton acceptor accepts electrons and protons from different donors. It exploits the long-range nature of electron transfer while providing for the short-range nature of proton transfer. A variety of EPT pathways exist, creating a taxonomy based on what is transferred, e.g., 1e{sup -}/2H{sup +} MS-EPT. PCET achieves “redox potential leveling” between sequential couples and the buildup of multiple redox equivalents, which is of importance in multielectron catalysis. There are many examples of PCET and pH-dependent redox behavior in metal complexes, in organic and biological molecules, in excited states, and on surfaces. Changes in pH can be used to induce electron transfer through films and over long distances in molecules. Changes in pH, induced by local electron transfer, create pH gradients and a driving force for long-range proton transfer in Photosysem II and through other biological membranes. In EPT, simultaneous transfer of electrons and protons occurs on time scales short compared to the periods of coupled vibrations and solvent modes. A theory for EPT has been developed which rationalizes rate constants and activation barriers, includes temperature- and driving force (?G)-dependences implicitly, and explains kinetic isotope effects. The distance-dependence of EPT is dominated by the short-range nature of proton transfer, with electron transfer being far less demanding.Changes in external pH do not affect an EPT elementary step. Solvent molecules or buffer components can act as proton donor acceptors, but individual H2O molecules are neither good bases (pK{sub a}(H{sub 3}O{sup +}) = ?1.74) nor good acids (pK{sub a}(H{sub 2}O) = 15.7). There are many examples of mechanisms in chemistry, in biology, on surfaces, and in the gas phase which utilize EPT. PCET and EPT play critical roles in the oxygen evolving complex (OEC) of Photosystem II and other biological reactions by decreasing driving force and avoiding high-energy intermediates.

  6. Scanning Transmission Electron Microscopy Investigations of Complex...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Scanning Transmission Electron Microscopy Investigations of Complex Oxides Monday, May 23, 2011 - 3:30pm SSRL Conference room 137-322 Professor Tom Vogt, NanoCenter & Department of...

  7. Transmission electron microscope CCD camera

    DOE Patents [OSTI]

    Downing, Kenneth H. (Lafayette, CA)

    1999-01-01T23:59:59.000Z

    In order to improve the performance of a CCD camera on a high voltage electron microscope, an electron decelerator is inserted between the microscope column and the CCD. This arrangement optimizes the interaction of the electron beam with the scintillator of the CCD camera while retaining optimization of the microscope optics and of the interaction of the beam with the specimen. Changing the electron beam energy between the specimen and camera allows both to be optimized.

  8. In-situ Transmission Electron Microscopy and Spectroscopy Studies...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Transmission Electron Microscopy and Spectroscopy Studies of Interfaces in Li-ion Batteries: Challenges and In-situ Transmission Electron Microscopy and Spectroscopy Studies of...

  9. CFN | Hitachi HD2700C Scanning Transmission Electron Microscope

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Hitachi HD2700C Scanning Transmission Electron Microscope Contacts: Dong Su | Lihua Zhang | Huolin Xin The Hitachi 2700C is a dedicated Scanning Transmission Electron Microscope...

  10. Engineering nanocarbon interfaces for electron transfer

    E-Print Network [OSTI]

    Hilmer, Andrew J. (Andrew Joseph)

    2013-01-01T23:59:59.000Z

    Electron-transfer reactions at nanometer-scale interfaces, such as those presented by single-walled carbon nanotubes (SWCNTs), are important for emerging optoelectronic and photovoltaic technologies. Electron transfer also ...

  11. Nonlinear transmission line based electron beam driver

    SciTech Connect (OSTI)

    French, David M.; Hoff, Brad W.; Tang Wilkin; Heidger, Susan; Shiffler, Don [Directed Energy Directorate, Air Force Research Laboratory, Kirtland AFB, New Mexico 87117 (United States); Allen-Flowers, Jordan [Program in Applied Mathematics, University of Arizona, Tucson, Arizona 85721 (United States)

    2012-12-15T23:59:59.000Z

    Gated field emission cathodes can provide short electron pulses without the requirement of laser systems or cathode heating required by photoemission or thermionic cathodes. The large electric field requirement for field emission to take place can be achieved by using a high aspect ratio cathode with a large field enhancement factor which reduces the voltage requirement for emission. In this paper, a cathode gate driver based on the output pulse train from a nonlinear transmission line is experimentally demonstrated. The application of the pulse train to a tufted carbon fiber field emission cathode generates short electron pulses. The pulses are approximately 2 ns in duration with emission currents of several mA, and the train contains up to 6 pulses at a frequency of 100 MHz. Particle-in-cell simulation is used to predict the characteristic of the current pulse train generated from a single carbon fiber field emission cathode using the same technique.

  12. In-Situ Transmission Electron Microscopy Probing of Native Oxide...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Probing of Native Oxide and Artificial Layers on Silicon Nanoparticles for Lithium Ion In-Situ Transmission Electron Microscopy Probing of Native Oxide and Artificial...

  13. New Developments in Transmission Electron Microscopy for Nanotechnology**

    E-Print Network [OSTI]

    Wang, Zhong L.

    New Developments in Transmission Electron Microscopy for Nanotechnology** By Zhong Lin Wang* 1. Electron Microscopy and Nanotechnology Nanotechnology, as an international initiative for science manufacturing are the foundation of nanotechnology. Tracking the historical background of why nanotechnology

  14. Vectorial electron transfer in spatially ordered arrays

    SciTech Connect (OSTI)

    Fox, M.A.

    1993-02-01T23:59:59.000Z

    Progress was made on synthesis of new materials for directional electron transfer (block copolymers and helical oligopeptides), preparation and characterization of anisotropic composites bearing organics and inorganics, electrocatalysis (redox-activated catalysts), and surface modifications of metals and semiconductors.

  15. Molecular Dynamics Investigation of Ferrous-Ferric Electron Transfer...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Electron Transfer in a Hydrolyzing Aqueous Solution: Calculation of the pH Molecular Dynamics Investigation of Ferrous-Ferric Electron Transfer in a Hydrolyzing Aqueous Solution:...

  16. Redox-linked conformation change and electron transfer between...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    processes, including electron transfer from dissimilatory metal-reducing bacteria to minerals. One of the pathways that could trigger electron transfer between proteins and...

  17. Intermittent Single-Molecule Interfacial Electron Transfer Dynamics...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Intermittent Single-Molecule Interfacial Electron Transfer Dynamics. Intermittent Single-Molecule Interfacial Electron Transfer Dynamics. Abstract: We report on single molecule...

  18. Single Molecule Spectroscopy of Electron Transfer

    SciTech Connect (OSTI)

    Michael Holman; Ling Zang; Ruchuan Liu; David M. Adams

    2009-10-20T23:59:59.000Z

    The objectives of this research are threefold: (1) to develop methods for the study electron transfer processes at the single molecule level, (2) to develop a series of modifiable and structurally well defined molecular and nanoparticle systems suitable for detailed single molecule/particle and bulk spectroscopic investigation, (3) to relate experiment to theory in order to elucidate the dependence of electron transfer processes on molecular and electronic structure, coupling and reorganization energies. We have begun the systematic development of single molecule spectroscopy (SMS) of electron transfer and summaries of recent studies are shown. There is a tremendous need for experiments designed to probe the discrete electronic and molecular dynamic fluctuations of single molecules near electrodes and at nanoparticle surfaces. Single molecule spectroscopy (SMS) has emerged as a powerful method to measure properties of individual molecules which would normally be obscured in ensemble-averaged measurement. Fluctuations in the fluorescence time trajectories contain detailed molecular level statistical and dynamical information of the system. The full distribution of a molecular property is revealed in the stochastic fluctuations, giving information about the range of possible behaviors that lead to the ensemble average. In the case of electron transfer, this level of understanding is particularly important to the field of molecular and nanoscale electronics: from a device-design standpoint, understanding and controlling this picture of the overall range of possible behaviors will likely prove to be as important as designing ia the ideal behavior of any given molecule.

  19. Group transfer and electron transfer reactions of organometallic complexes

    SciTech Connect (OSTI)

    Atwood, J.D.

    1994-12-01T23:59:59.000Z

    During 1994, despite the disruptions, the authors have made progress in several aspects of their research on electron transfer reactions between organometallic complexes. This summary covers three areas that are relatively complete: (1) reactions between metal carbonyl anions and metal carbonyl halides, (2) reactions of hydrido- and alkyl-containing anions (RFe(CO){sup {minus}}{sub 4} and RW (CO){sub 5}{sup {minus}}) with metal carbonyl cations and (3) reactions of a seventeen-electron complex (Cp{asterisk}Cr(CO){sub 3}{lg_bullet}) with metal carbonyl derivatives. Two areas of examination that have just begun (possible carbene transfer and the possible role of metal carbonyl anions in carbon-hydrogen bond activation) will also be described.

  20. Image Resolution in Scanning Transmission Electron Microscopy

    SciTech Connect (OSTI)

    Pennycook, S. J.; Lupini, A.R.

    2008-06-26T23:59:59.000Z

    Digital images captured with electron microscopes are corrupted by two fundamental effects: shot noise resulting from electron counting statistics and blur resulting from the nonzero width of the focused electron beam. The generic problem of computationally undoing these effects is called image reconstruction and for decades has proved to be one of the most challenging and important problems in imaging science. This proposal concerned the application of the Pixon method, the highest-performance image-reconstruction algorithm yet devised, to the enhancement of images obtained from the highest-resolution electron microscopes in the world, now in operation at Oak Ridge National Laboratory.

  1. Power electronics in electric utilities: HVDC power transmission systems

    SciTech Connect (OSTI)

    Nozari, F.; Patel, H.S.

    1988-04-01T23:59:59.000Z

    High Voltage Direct Current (HVDC) power transmission systems constitute an important application of power electronics technology. This paper reviews salient aspects of this growing industry. The paper summarizes the history of HVDC transmission and discusses the economic and technical reasons responsible for development of HVDC systems. The paper also describes terminal design and basic configurations of HVDC systems, as well as major equipments of HVDC transmission system. In this regard, the state-of-the-art technology in the equipments constructions are discussed. Finally, the paper reviews future developments in the HVDC transmission systems, including promising technologies, such as multiterminal configurations, Gate Turn-Off (GTO) devices, forced commutation converters, and new advances in control electronics.

  2. Photoinduced electron transfer reactions in zeolite cages

    SciTech Connect (OSTI)

    Dutta, P.K.

    1992-01-01T23:59:59.000Z

    This report summarizes work in the two areas of zeolites and layered double hydroxides. Results of studies on structural aspects of Ru(bpy)[sub 3][sup 2+]-zeolite Y are summarized. Photoinduced electron transfer between entrapped Ru(bpy)[sub 3][sup 2+] and methylviologen (MV) in neighboring supercages was examined. Benzylviologen was also used. Since molecules larger than 13 [angstrom] cannot be accomodated in zeolite cages, the layered double metal hydroxides (LDH) LiAl[sub 2](OH)[sub 6][sup +]X[sup [minus

  3. Complex modes and new amplification regimes in periodic multi transmission lines interacting with an electron beam

    E-Print Network [OSTI]

    Othman, Mohamed; Capolino, Filippo

    2014-01-01T23:59:59.000Z

    We show the existence of a new regime of operation for travelling wave tubes (TWTs) composed of slow-wave periodic structures that support two or more electromagnetic modes, with at least two synchronized with an electron beam. The interaction between the slow-wave structure and an electron beam is quantified using a multi transmission line approach (MTL) and transfer matrix analysis leading to the identification of modes with complex Bloch wavenumber. In particular, we report a new operation condition for TWTs based on an electron beam synchronous to two modes exhibiting a degeneracy condition near a band edge in a MTL slow-wave periodic structure. We show a phenomenological change in the band structure of periodic TWT where we observe at least two growing modal cooperating solutions as opposed to a uniform MTL interacting with an electron beam where there is strictly only one growing mode solution.

  4. Transmission of High-Power Electron Beams Through Small Apertures

    SciTech Connect (OSTI)

    Tschalaer, Christoph [MIT Bates Linear Accelerator; Alarcon, Ricardo O.; Balascuta, S.; Benson, Stephen V. [JLAB; Bertozzi, William; Boyce, James R. [College of William and Mary; Cowan, Ray Franklin [MIT; Douglas, David R. [JLAB; Evtushenko, Pavel [JLAB; Fisher, Peter H.; Ihloff, Ernest E. [MIT Bates Linear Accelerator; Kalantarians, Narbe [Unversity of Texas; Kelleher, Aidan Michael [MIT Bates Linear Accelerator; Legg, Robert A. [JLAB; Milner, Richard; Neil, George R. [JLAB; Ou, Longwu [MIT; Schmookler, Barak Abraham [MIT; Tennant, Christopher D. [JLAB; Williams, Gwyn P. [JLAB; Zhang, Shukui [JLAB

    2013-11-01T23:59:59.000Z

    Tests were performed to pass a 100 MeV, 430 kWatt c.w. electron beam from the energy-recovery linac at the Jefferson Laboratory's FEL facility through a set of small apertures in a 127 mm long aluminum block. Beam transmission losses of 3 p.p.m. through a 2 mm diameter aperture were maintained during a 7 hour continuous run.

  5. Pulsed Power for a Dynamic Transmission Electron Microscope

    SciTech Connect (OSTI)

    dehope, w j; browning, n; campbell, g; cook, e; king, w; lagrange, t; reed, b; stuart, b; Shuttlesworth, R; Pyke, B

    2009-06-25T23:59:59.000Z

    Lawrence Livermore National Laboratory (LLNL) has converted a commercial 200kV transmission electron microscope (TEM) into an ultrafast, nanoscale diagnostic tool for material science studies. The resulting Dynamic Transmission Electron Microscope (DTEM) has provided a unique tool for the study of material phase transitions, reaction front analyses, and other studies in the fields of chemistry, materials science, and biology. The TEM's thermionic electron emission source was replaced with a fast photocathode and a laser beam path was provided for ultraviolet surface illumination. The resulting photoelectron beam gives downstream images of 2 and 20 ns exposure times at 100 and 10 nm spatial resolution. A separate laser, used as a pump pulse, is used to heat, ignite, or shock samples while the photocathode electron pulses, carefully time-synchronized with the pump, function as probe in fast transient studies. The device functions in both imaging and diffraction modes. A laser upgrade is underway to make arbitrary cathode pulse trains of variable pulse width of 10-1000 ns. Along with a fast e-beam deflection scheme, a 'movie mode' capability will be added to this unique diagnostic tool. This talk will review conventional electron microscopy and its limitations, discuss the development and capabilities of DTEM, in particularly addressing the prime and pulsed power considerations in the design and fabrication of the DTEM, and conclude with the presentation of a deflector and solid-state pulser design for Movie-Mode DTEM.

  6. Comparing the Primary Electron Transfer Process in Organic Photovoltai...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Comparing the Primary Electron Transfer Process in Organic Photovoltaic Heterojunctions with Photosynthetic Reaction Centers October 4, 2011 at 3pm36-428 Garry Rumbles National...

  7. Exploring Electron Transfer in Organic Semiconductors | MIT-Harvard...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Electron Transfer in Organic Semiconductors January 28, 2009 at 3pm36-428 Troy Van Voorhis Department of Chemistry, Massachusetts Institute of Technology vanvoorhis2000 abstract:...

  8. Electron transfer reactions in microporous solids

    SciTech Connect (OSTI)

    Mallouk, T.E.

    1992-05-01T23:59:59.000Z

    We have studied electron transfer quenching of the excited state of Ru(bpy){sub 3}{sup 2+} in aqueous suspensions of zeolites Y, L, and mordenite. The internal pore network of the zeolite is ion-exchanged with methylviologen cations, which quench the excited state of the surface-bound sensitizer. A detailed study of the quenching and charge recombination kinetics, using time-resolved luminescence quenching and transient diffuse reflectance spectroscopies, shows to remarkable effects: first, the excited state quenching is entirely dynamic is large-pore zeolites (L and Y), even when they are prepared as apparently dry'' powders (which still contain significant amounts of internally sited water). Second, a lower limit for the diffusion coefficient of the MV{sup 2+} ion in these zeolites, determined by this technique, is 10{sup {minus}7} cm{sup 2}sec, i.e., only about one order of magnitude slower than a typical ion in liquid water, and 2--3 orders of magnitude faster than charge transfer diffusion of cations in polyelectrolyte films or membranes such as Nafion. Surface sensitization of internally platinized layered oxide semiconductors such as K{sub 4-x}H{sub x}Nb{sub 6}O{sub 17}{center dot}nH{sub 2}O (x {approx} 2.5) yields photocatalysts for the production of H{sub 2} and I{sub 3{minus}} in aqueous iodide solutions. Layered alkali niobates and titanates form a class of zeolitic wide-bandap semiconductors, and are the first examples of photocatalysts that evolve hydrogen from an electrochemically reversible (i.e., non-sacrificial) electron donor with visible light excitation.

  9. Precision electron flow measurements in a disk transmission line.

    SciTech Connect (OSTI)

    Clark, Waylon T.; Pelock, Michael D.; Martin, Jeremy Paul; Jackson, Daniel Peter Jr.; Savage, Mark Edward; Stoltzfus, Brian Scott; Mendel, Clifford Will, Jr.; Pointon, Timothy David

    2008-01-01T23:59:59.000Z

    An analytic model for electron flow in a system driving a fixed inductive load is described and evaluated with particle in cell simulations. The simple model allows determining the impedance profile for a magnetically insulated transmission line given the minimum gap desired, and the lumped inductance inside the transition to the minimum gap. The model allows specifying the relative electron flow along the power flow direction, including cases where the fractional electron flow decreases in the power flow direction. The electrons are able to return to the cathode because they gain energy from the temporally rising magnetic field. The simulations were done with small cell size to reduce numerical heating. An experiment to compare electron flow to the simulations was done. The measured electron flow is {approx}33% of the value from the simulations. The discrepancy is assumed to be due to a reversed electric field at the cathode because of the inductive load and falling electron drift velocity in the power flow direction. The simulations constrain the cathode electric field to zero, which gives the highest possible electron flow.

  10. Photocathode Optimization for a Dynamic Transmission Electron Microscope: Final Report

    SciTech Connect (OSTI)

    Ellis, P; Flom, Z; Heinselman, K; Nguyen, T; Tung, S; Haskell, R; Reed, B W; LaGrange, T

    2011-08-04T23:59:59.000Z

    The Dynamic Transmission Electron Microscope (DTEM) team at Harvey Mudd College has been sponsored by LLNL to design and build a test setup for optimizing the performance of the DTEM's electron source. Unlike a traditional TEM, the DTEM achieves much faster exposure times by using photoemission from a photocathode to produce electrons for imaging. The DTEM team's work is motivated by the need to improve the coherence and current density of the electron cloud produced by the electron gun in order to increase the image resolution and contrast achievable by DTEM. The photoemission test setup is nearly complete and the team will soon complete baseline tests of electron gun performance. The photoemission laser and high voltage power supply have been repaired; the optics path for relaying the laser to the photocathode has been finalized, assembled, and aligned; the internal setup of the vacuum chamber has been finalized and mostly implemented; and system control, synchronization, and data acquisition has been implemented in LabVIEW. Immediate future work includes determining a consistent alignment procedure to place the laser waist on the photocathode, and taking baseline performance measurements of the tantalum photocathode. Future research will examine the performance of the electron gun as a function of the photoemission laser profile, the photocathode material, and the geometry and voltages of the accelerating and focusing components in the electron gun. This report presents the team's progress and outlines the work that remains.

  11. Transmission Services WIST Task Force Dynamic Transfer Capability...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    WIST Task Force Dynamic Transfer Capability Report - Phase I BPA is an active participant in the Wind Integration Study Team (WIST), especially the Task Force looking at DTC study...

  12. Electron transfer and protein engineering studies of the soluble methane monooxygenase from Methylococcus capsulatus (Bath)

    E-Print Network [OSTI]

    Blazyk, Jessica L. (Jessica Lee), 1974-

    2003-01-01T23:59:59.000Z

    Chapter 1. Introduction: Electron Transfer in Biological Systems In many biological processes, including oxidative phosphorylation and photosynthesis, electron transfer reactions play vital roles. Electrons must be transported ...

  13. In-Situ Electrochemical Transmission Electron Microscopy for Battery Research

    SciTech Connect (OSTI)

    Mehdi, Beata L [Pacific Northwest National Laboratory (PNNL)] [Pacific Northwest National Laboratory (PNNL); Gu, Meng [Pacific Northwest National Laboratory (PNNL)] [Pacific Northwest National Laboratory (PNNL); Parent, Lucas [Pacific Northwest National Laboratory (PNNL)] [Pacific Northwest National Laboratory (PNNL); Xu, WU [Pacific Northwest National Laboratory (PNNL)] [Pacific Northwest National Laboratory (PNNL); Nasybulin, Eduard [Pacific Northwest National Laboratory (PNNL)] [Pacific Northwest National Laboratory (PNNL); Chen, Xilin [Pacific Northwest National Laboratory (PNNL)] [Pacific Northwest National Laboratory (PNNL); Unocic, Raymond R [ORNL] [ORNL; Xu, Pinghong [University of California, Davis] [University of California, Davis; Welch, David [Pacific Northwest National Laboratory (PNNL)] [Pacific Northwest National Laboratory (PNNL); Abellan, Patricia [Pacific Northwest National Laboratory (PNNL)] [Pacific Northwest National Laboratory (PNNL); Zhang, Ji-Guang [Pacific Northwest National Laboratory (PNNL)] [Pacific Northwest National Laboratory (PNNL); Liu, Jun [Pacific Northwest National Laboratory (PNNL)] [Pacific Northwest National Laboratory (PNNL); Wang, Chongmin [Pacific Northwest National Laboratory (PNNL)] [Pacific Northwest National Laboratory (PNNL); Arslan, Ilke [Pacific Northwest National Laboratory (PNNL)] [Pacific Northwest National Laboratory (PNNL); Evans, James E [Pacific Northwest National Laboratory (PNNL)] [Pacific Northwest National Laboratory (PNNL); Browning, Nigel [Pacific Northwest National Laboratory (PNNL)] [Pacific Northwest National Laboratory (PNNL)

    2014-01-01T23:59:59.000Z

    The recent development of in-situ liquid stages for (scanning) transmission electron microscopes now makes it possible for us to study the details of electrochemical processes under operando conditions. As electrochemical processes are complex, care must be taken to calibrate the system before any in-situ/operando observations. In addition, as the electron beam can cause effects that look similar to electrochemical processes at the electrolyte/electrode interface, an understanding of the role of the electron beam in modifying the operando observations must also be understood. In this paper we describe the design, assembly, and operation of an in-situ electrochemical cell, paying particular attention to the method for controlling and quantifying the experimental parameters. The use of this system is then demonstrated for the lithiation/delithiation of silicon nanowires.

  14. Transmission electron microscopy of undermined passive films on stainless steel

    SciTech Connect (OSTI)

    Isaacs, H.S.; Zhu, Y.; Sabatini, R.L. [Brookhaven National Lab., Upton, NY (United States). Dept. of Applied Science; Ryan, M.P. [Imperial Coll. of Science, Technology and Medicine, London (United Kingdom). Dept. of Materials

    1999-06-01T23:59:59.000Z

    A study has been made of the passive film remaining over pits on stainless steel using a high resolution transmission electron microscope. Type 305 stainless steel was passivated in a borate buffer solution and pitted in ferric chloride. Passive films formed at 0.2 V relative to a saturated calomel electrode were found to be amorphous. Films formed at higher potentials showed only broad diffraction rings. The passive film was found to cover a remnant lacy structure formed over pits passivated at 0.8 V. The metallic strands of the lace were roughly hemitubular in shape with the curved surface facing the center of the pit.

  15. Combined Scanning Transmission Electron Microscopy Tilt- and Focal Series

    SciTech Connect (OSTI)

    Dahmen, Tim [German Research Center for Artificial Intelligence (DFKI), Germany] [German Research Center for Artificial Intelligence (DFKI), Germany; Baudoin, Jean-Pierre G [ORNL] [ORNL; Lupini, Andrew R [ORNL] [ORNL; Kubel, Christian [Karlsruhe Institute of Technology, Leopoldshafen, Germany] [Karlsruhe Institute of Technology, Leopoldshafen, Germany; Slusallek, Phillip [German Research Center for Artificial Intelligence (DFKI), Germany] [German Research Center for Artificial Intelligence (DFKI), Germany; De Jonge, Niels [ORNL] [ORNL

    2014-01-01T23:59:59.000Z

    In this study, a combined tilt- and focal series is proposed as a new recording scheme for high-angle annular dark-field scanning transmission electron microscopy (STEM) tomography. Three-dimensional (3D) data were acquired by mechanically tilting the specimen, and recording a through-focal series at each tilt direction. The sample was a whole-mount macrophage cell with embedded gold nanoparticles. The tilt focal algebraic reconstruction technique (TF-ART) is introduced as a new algorithm to reconstruct tomograms from such combined tilt- and focal series. The feasibility of TF-ART was demonstrated by 3D reconstruction of the experimental 3D data. The results were compared with a conventional STEM tilt series of a similar sample. The combined tilt- and focal series led to smaller missing wedge artifacts, and a higher axial resolution than obtained for the STEM tilt series, thus improving on one of the main issues of tilt series-based electron tomography.

  16. Frontier orbital symmetry control of intermolecular electron transfer. Final report, September 15, 1988--December 31, 1994

    SciTech Connect (OSTI)

    Stevens, B.

    1997-07-01T23:59:59.000Z

    This report discusses the following topics: the recovery of intermolecular transfer parameters from fluorescence quenching in liquids; photoinduced intramolecular electron transfer in flexible donor/space/acceptor systems containing an extended unsaturated spacer; electron transfer sensitized reaction; the recovery of solute and fractal dimensions from electron transfer quenching data; and frontier orbital symmetry control of back electron transfer.

  17. Global electronic funds transfer between small and medium sized companies

    E-Print Network [OSTI]

    Stovall, Shawn Eric

    2006-01-01T23:59:59.000Z

    Cross-border electronic funds transfer is a rapidly expanding field for business and consumer payments. Large multi-national corporations have been able to invest the capital necessary to create infrastructures or work ...

  18. Monitoring Long-Range Electron Transfer Pathways in Proteins...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    structure and should offer a novel window for long-range ET. Citation: Zhang Y, J Biggs, N Govind, and S Mukamel.2014."Monitoring Long-Range Electron Transfer Pathways in...

  19. Transmission electron microscopy of whiskers and hillocks formed on Al films deposited onto a glass

    SciTech Connect (OSTI)

    Saka, H.; Fujino, S.; Kuroda, K. [Department of Quantum Engineering, Nagoya University, Nagoya 464-01 (Japan); Tsujimoto, K.; Tsuji, S. [Display Technology, IBM Japan, Ltd., Shimotsuruma, Yamato, Kanagawa 242 (Japan); Takatsuji, H. [Display Technology, IBM Japan, Ltd., Ichimiyake, Yasu-gun, Shiga 520-23 (Japan)

    1998-01-05T23:59:59.000Z

    Whiskers and hillocks formed on an Al film deposited onto a glass substrate have been observed by means of a variety of transmission electron microscopy technique.

  20. Dynamic studies of catalysts for biofuel synthesis in an Environmental Transmission Electron Microscope

    E-Print Network [OSTI]

    Dunin-Borkowski, Rafal E.

    Dynamic studies of catalysts for biofuel synthesis in an Environmental Transmission Electron@cen.dtu.dk Keywords: Biofuel, catalysis, environmental TEM The development of transportation fuels from sustainable

  1. Amyloid Structure and Assembly: Insights from Scanning Transmission Electron Microscopy

    SciTech Connect (OSTI)

    Goldsbury, C.; Wall, J.; Baxa, U.; Simon, M. N.; Steven, A. C.; Engel, A.; Aebi, U.; Muller, S. A.

    2011-01-01T23:59:59.000Z

    Amyloid fibrils are filamentous protein aggregates implicated in several common diseases such as Alzheimer's disease and type II diabetes. Similar structures are also the molecular principle of the infectious spongiform encephalopathies such as Creutzfeldt-Jakob disease in humans, scrapie in sheep, and of the so-called yeast prions, inherited non-chromosomal elements found in yeast and fungi. Scanning transmission electron microscopy (STEM) is often used to delineate the assembly mechanism and structural properties of amyloid aggregates. In this review we consider specifically contributions and limitations of STEM for the investigation of amyloid assembly pathways, fibril polymorphisms and structural models of amyloid fibrils. This type of microscopy provides the only method to directly measure the mass-per-length (MPL) of individual filaments. Made on both in vitro assembled and ex vivo samples, STEM mass measurements have illuminated the hierarchical relationships between amyloid fibrils and revealed that polymorphic fibrils and various globular oligomers can assemble simultaneously from a single polypeptide. The MPLs also impose strong constraints on possible packing schemes, assisting in molecular model building when combined with high-resolution methods like solid-state nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR).

  2. Electron Transfer DOI: 10.1002/anie.200603822

    E-Print Network [OSTI]

    Borguet, Eric

    to areas such as molecular electronics, electro- chemistry, biology, catalysis, information storage, and solar- energy conversion.[1­4] Therefore, understanding interfacial electron transfer between molecules electrode. [*] Y. He, Prof. E. Borguet Department of Chemistry Temple University Philadelphia, PA 19122 (USA

  3. Dislocation mobility in gum metal -titanium alloy studied via in situ transmission electron microscopy

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Dislocation mobility in gum metal -titanium alloy studied via in situ transmission electron in a transmission electron microscope were carried out on a "Gum Metal" titanium alloy. Conventional dislocation and the variation in energy due to the core structure of screw dislocations were measured and compared

  4. TRANSMISSION ELECTRON MICROSCOPY STUDY OF HELIUM BEARING FUSION WELDS

    SciTech Connect (OSTI)

    Tosten, M; Michael Morgan, M

    2008-12-12T23:59:59.000Z

    A transmission electron microscopy (TEM) study was conducted to characterize the helium bubble distributions in tritium-charged-and-aged 304L and 21Cr-6Ni-9Mn stainless steel fusion welds containing approximately 150 appm helium-3. TEM foils were prepared from C-shaped fracture toughness test specimens containing {delta} ferrite levels ranging from 4 to 33 volume percent. The weld microstructures in the low ferrite welds consisted mostly of austenite and discontinuous, skeletal {delta} ferrite. In welds with higher levels of {delta} ferrite, the ferrite was more continuous and, in some areas of the 33 volume percent sample, was the matrix/majority phase. The helium bubble microstructures observed were similar in all samples. Bubbles were found in the austenite but not in the {delta} ferrite. In the austenite, bubbles had nucleated homogeneously in the grain interiors and heterogeneously on dislocations. Bubbles were not found on any austenite/austenite grain boundaries or at the austenite/{delta} ferrite interphase interfaces. Bubbles were not observed in the {delta} ferrite because of the combined effects of the low solubility and rapid diffusion of tritium through the {delta} ferrite which limited the amount of helium present to form visible bubbles.

  5. Electron transfer reactions in microporous solids

    SciTech Connect (OSTI)

    Mallouk, T.E.

    1993-01-01T23:59:59.000Z

    Basic thrust the research program involves use of microporous solids (zeolites, clays, layered and tunnel structure oxide semiconductors) as organizing media for artificial photosynthetic systems. Purpose of the microporous solid is twofold. First, it induces spatial organization of photoactive and electroactive components (sensitizers, semiconductor particles, electron relays, and catalysts) at the solid-solution interface, enhancing the quantum efficiency of charge separation and separating physically the ultimate electron donor and acceptor in the electron transport chain. Second, since the microcrystalline solid admits only molecules of a certain charge and size, it is possible to achieve permanent charge separation by sieving chemical photoproducts (e.g., H[sub 2] and I[sub 3][sup [minus

  6. Photoinduced electron transfer processes in homogeneous and microheterogeneous solutions

    SciTech Connect (OSTI)

    Whitten, D.G.

    1992-12-01T23:59:59.000Z

    The studies have focused on rapid, efficient bond-fragmentation reactions initiated through photoinduced electron transfer. Electron transfer induced fragmentation of a number of donors have been examined, especially 1,2 diamines and related compounds. Two of the amines fragment with rate constants of 3 [times] 10[sup 8] to 2 [times] 10[sup 9] M[sup [minus]1]sec[sup [minus]1]. A series of amino-substituted pinacols and related compounds have also been examined; they undergo similar but slower fragmentation processes when converted to their cation radicals by photoinduced electron transfer. The studies with linked and polymeric electron donor- electron acceptor coupled molecules have also progressed. Several polymers containing diamine repeat units and anthraquinone or nitroaromatic acceptors have also been prepared that can be photoactivated by visible irradiation; they fragment efficiently in solution and photodegrade even in the solid state. The studies of singlet oxygen initiated fragmentation reactions of diamines, amino alcohols, and aminoketones have nearly been completed. Attention have been turned to fragmentable electron acceptors such as p- cyanobenzyl bromide; irradiation of electron donors such as methyl- or methoxy-naphthalenes can initiate efficient fragmentation of the electron deficient bromide.

  7. Photoinduced electron transfer processes in homogeneous and microheterogeneous solutions

    SciTech Connect (OSTI)

    Whitten, D.G.

    1991-10-01T23:59:59.000Z

    The focus of the work described in this report is on single electron transfer reactions of excited states which culminate in the formation of stable or metastable even electron species. For the most part the studies have involved even electron organic substrates which are thus converted photochemically to odd electron species and then at some stage reconvert to even electron products. These reactions generally fall into two rather different categories. In one set of studies we have examined reactions in which the metastable reagents generated by single electron transfer quenching of an excited state undergo novel fragmentation reactions, chiefly involving C-C bond cleavage. These reactions often culminate in novel and potentially useful chemical reactions and frequently have the potential for leading to new chemical products otherwise unaffordable by conventional reaction paths. In a rather different investigation we have also studied reactions in which single electron transfer quenching of an excited state is followed by subsequent reactions which lead reversibly to metastable two electron products which, often stable in themselves, can nonetheless be reacted with each other or with other reagents to regenerate the starting materials with release of energy. 66 refs., 9 figs., 1 tab.

  8. Electron Transfer Between Colloidal ZnO Nanocrystals

    SciTech Connect (OSTI)

    Hayoun, Rebecca; Whitaker, Kelly M.; Gamelin, Daniel R.; Mayer, James M.

    2011-03-30T23:59:59.000Z

    Colloidal ZnO nanocrystals capped with dodecylamine and dissolved in toluene can be charged photochemically to give stable solutions in which electrons are present in the conduction bands of the nanocrystals. These conduction-band electrons are readily monitored by EPR spectroscopy, with g* values that correlate with the nanocrystal sizes. Mixing a solution of charged small nanocrystals (e{sub CB}{sup -}:ZnO-S) with a solution of uncharged large nanocrystals (ZnO-L) caused changes in the EPR spectrum indicative of quantitative electron transfer from small to large nanocrystals. EPR spectra of the reverse reaction, e{sub CB}{sup -}:ZnO-L + ZnO-S, showed that electrons do not transfer from large to small nanocrystals. Stopped-flow kinetics studies monitoring the change in the UV bandedge absorption showed that reactions of 50 {micro}M nanocrystals were complete within the 5 ms mixing time of the instrument. Similar results were obtained for the reaction of charged nanocrystals with methyl viologen (MV{sup 2+}). These and related results indicate that the electron-transfer reactions of these colloidal nanocrystals are quantitative and very rapid, despite the presence of {approx}1.5 nm long dodecylamine capping ligands. These soluble ZnO nanocrystals are thus well-defined redox reagents suitable for studies of electron transfer involving semiconductor nanostructures.

  9. Vectorial electron transfer in spatially ordered arrays

    SciTech Connect (OSTI)

    Fox, M.A.

    1992-01-01T23:59:59.000Z

    Progress has been made in four areas: the synthesis of new materials for directional electron; the preparation and characterization of anisotropic composites bearing organic and inorganic components; the elaboration of mechanisms of electrocatalysis; and the development of new methods for surface modification of metals and semiconductors.

  10. Long-distance photoinitiated electron transfer through polyene molecular wires

    SciTech Connect (OSTI)

    Wasielewski, M.R.; Johnson, D.G.; Svec, W.A.; Kersey, K.M.; Cragg, D.E.; Minsek, D.W.

    1988-01-01T23:59:59.000Z

    Long-chain polyenes can be used as molecular wires to facilitate electron transfer between a photo-excited donor and an acceptor in an artificial photosynthetic system. The authors present data here on two Zn-porphyrin-polyene-anthraquinone molecules possessing either 5 or 9 all trans double bonds between the donor and acceptor, 1 and 2. The center-to-center distances between the porphyrin and the quinone in these relatively rigid molecules are 25 A for 1 and 35 A for 2. Selective picosecond laser excitation of the Zn-porphyrin in 1 and 2 results in the very rapid transfer of an electron to the anthraquinone in < 2 ps and 10 ps, respectively. The resultant radical ion pairs recombine with tau = 10 ps for 1 and tau = 25 ps for 2. The electron transfer rates remain remarkably rapid over these long distances. The involvement of polyene radical cations in the mechanism of the radical ion pair recombination reaction is clear from the transient absorption spectra of 1 and 2, which show strong absorbances in the near-infrared. The strong electronic coupling between the Zn-porphyrin and the anthraquinone provided by low-lying states of the polyene make it possible to transfer an electron rapidly over very long distances.

  11. Shewanella secretes flavins that mediate extracellular electron transfer

    E-Print Network [OSTI]

    Weiblen, George D

    to the electrode. A combination of methods identified a mixture of ribofla- vin and riboflavin-5 -phosphate in supernatants from biofilm reac- tors, with riboflavin representing the dominant component during sustained incubations (>72 h). Removal of riboflavin from biofilms reduced the rate of electron transfer to electrodes

  12. FLUID MECHANICS AND HEAT TRANSFER OF ELECTRON FLOW IN SEMICONDUCTORS

    E-Print Network [OSTI]

    Sen, Mihir

    = heat, f = LO-mode, g = LO, h = LA-mode, i = negligible, j = remote heat sink 7/ 70 #12;Heat conductionFLUID MECHANICS AND HEAT TRANSFER OF ELECTRON FLOW IN SEMICONDUCTORS Mihir Sen Department · Shallow water analogy · Vorticity dynamics · Linear stability analysis · Numerical simulations of heat

  13. Interfacial Electron Transfer into Functionalized Crystalline Polyoxotitanate Nanoclusters

    E-Print Network [OSTI]

    Coppens, Philip

    processes in a dye-sensitized solar cell. Theoretical simulations of the electron transfer of molecular adsorption are precisely defined. INTRODUCTION Dye-sensitized solar cells (DSSC) promise the dye sensitizer into the conduction band of the semiconductor substrate. Naturally, the interfaces

  14. CORRELATING ELECTRONIC AND VIBRATIONAL MOTIONS IN CHARGE TRANSFER SYSTEMS

    SciTech Connect (OSTI)

    Khalil, Munira

    2014-06-27T23:59:59.000Z

    The goal of this research program was to measure coupled electronic and nuclear motions during photoinduced charge transfer processes in transition metal complexes by developing and using novel femtosecond spectroscopies. The scientific highlights and the resulting scientific publications from the DOE supported work are outlined in the technical report.

  15. Electronic Coupling Dependence of Ultrafast Interfacial Electron Transfer

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power AdministrationField Campaign:INEAWater UseC Supports - Energy3Electron-Stateon

  16. Mechanistic studies of photo-induced proton-coupled electron transfer and oxygen atom transfer reactions in model systems

    E-Print Network [OSTI]

    Hodgkiss, Justin M. (Justin Mark), 1978-

    2007-01-01T23:59:59.000Z

    Time-resolved optical spectroscopy has been employed for mechanistic studies in model systems designed to undergo photo-induced proton-coupled electron transfer (PCET) and oxygen atom transfer (OAT) reactions, both of which ...

  17. Spectroscopic investigation of photo-induced proton-coupled electron transfer and Dexter energy transfer in model systems

    E-Print Network [OSTI]

    Young, Elizabeth R. (Elizabeth Renee), 1980-

    2009-01-01T23:59:59.000Z

    Spectroscopic investigations of systems designed to advance the mechanistic interrogation of photo-induced proton coupled electron transfer (PCET) and proton-coupled (through-bond) energy transfer (PCEnT) are presented. ...

  18. Inclusive electron - nucleus scattering at large momentum transfer

    SciTech Connect (OSTI)

    J. Arrington; C. S. Armstrong; T. Averett; O. K. Baker; L. de Bever; C. W. Bochna; W. Boeglin; B. Bray; R. D. Carlini; G. Collins; C. Cothran; D. Crabb; D. Day; J. A. Dunne; D. Dutta; R. Ent; B. W. Filippone; A. Honegger; E. W. Hughes; J. Jensen; J. Jourdan; C. E. Keppel; D. M. Koltenuk; R. Lindgren; A. Lung; D. J. Mack; J. McCarthy; R. D. McKeown; D. Meekins; J. H. Mitchell; H. G. Mkrtchyan; G. Niculescu; I. Niculescu; T. Petitjean; O. Rondon; I. Sick; C. Smith; B. Terburg; W. F. Vulcan; S. A. Wood; C. Yan; J. Zhao; and B. Zihlmann

    1999-03-01T23:59:59.000Z

    Inclusive electron scattering is measured with 4.045 GeV incident beam energy from C, Fe, and Au targets. The measured energy transfers and angles correspond to a kinematic range for Bjorken x>1 and momentum transfers from Q2 = 1-7 (GeV/c)2. When analyzed in terms of the y-scaling function the data show for the first time an approach to scaling for values of the initial nucleon momenta significantly greater than the nuclear matter Fermi momentum (i.e., >0.3 GeV/c).

  19. Probing Electron Transfer Dynamics at MgO Surfaces by Mg-Atom...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Electron Transfer Dynamics at MgO Surfaces by Mg-Atom Desorption. Probing Electron Transfer Dynamics at MgO Surfaces by Mg-Atom Desorption. Abstract: Desorption of a weakly bound...

  20. The electron transfer system of syntrophically grown Desulfovibrio vulgaris

    SciTech Connect (OSTI)

    Walker, C.B.; He, Z.; Yang, Z.K.; Ringbauer, Jr., J.A.; He, Q.; Zhou, J.; Voordouw, G.; Wall, J.D.; Arkin, A.P.; Hazen, T.C.; Stolyar, S.; Stahl, D.A.

    2009-05-01T23:59:59.000Z

    Interspecies hydrogen transfer between organisms producing and consuming hydrogen promotes the decomposition of organic matter in most anoxic environments. Although syntrophic couplings between hydrogen producers and consumers are a major feature of the carbon cycle, mechanisms for energy recovery at the extremely low free energies of reactions typical of these anaerobic communities have not been established. In this study, comparative transcriptional analysis of a model sulfate-reducing microbe, Desulfovibrio vulgaris Hildenborough, suggested the use of alternative electron transfer systems dependent upon growth modality. During syntrophic growth on lactate with a hydrogenotrophic methanogen, D. vulgaris up-regulated numerous genes involved in electron transfer and energy generation when compared with sulfate-limited monocultures. In particular, genes coding for the putative membrane-bound Coo hydrogenase, two periplasmic hydrogenases (Hyd and Hyn) and the well-characterized high-molecular weight cytochrome (Hmc) were among the most highly expressed and up-regulated. Additionally, a predicted operon coding for genes involved in lactate transport and oxidation exhibited up-regulation, further suggesting an alternative pathway for electrons derived from lactate oxidation during syntrophic growth. Mutations in a subset of genes coding for Coo, Hmc, Hyd and Hyn impaired or severely limited syntrophic growth but had little affect on growth via sulfate-respiration. These results demonstrate that syntrophic growth and sulfate-respiration use largely independent energy generation pathways and imply that understanding of microbial processes sustaining nutrient cycling must consider lifestyles not captured in pure culture.

  1. The Electron Transfer System of Syntrophically Grown Desulfovibrio vulgaris

    SciTech Connect (OSTI)

    PBD; ENIGMA; GTL; VIMSS; Walker, Christopher B.; He, Zhili; Yang, Zamin K.; Ringbauer Jr., Joseph A.; He, Qiang; Zhou, Jizhong; Voordouw, Gerrit; Wall, Judy D.; Arkin, Adam P.; Hazen, Terry C.; Stolyar, Sergey; Stahl, David A.

    2009-06-22T23:59:59.000Z

    Interspecies hydrogen transfer between organisms producing and consuming hydrogen promotes the decomposition of organic matter in most anoxic environments. Although syntrophic couplings between hydrogen producers and consumers are a major feature of the carbon cycle, mechanisms for energy recovery at the extremely low free energies of reactions typical of these anaerobic communities have not been established. In this study, comparative transcriptional analysis of a model sulfate-reducing microbe, Desulfovibrio vulgaris Hildenborough, suggested the use of alternative electron transfer systems dependent upon growth modality. During syntrophic growth on lactate with a hydrogenotrophic methanogen, D. vulgaris up-regulated numerous genes involved in electron transfer and energy generation when compared with sulfate-limited monocultures. In particular, genes coding for the putative membrane-bound Coo hydrogenase, two periplasmic hydrogenases (Hyd and Hyn) and the well-characterized high-molecular weight cytochrome (Hmc) were among the most highly expressed and up-regulated. Additionally, a predicted operon coding for genes involved in lactate transport and oxidation exhibited up-regulation, further suggesting an alternative pathway for electrons derived from lactate oxidation during syntrophic growth. Mutations in a subset of genes coding for Coo, Hmc, Hyd and Hyn impaired or severely limited syntrophic growth but had little affect on growth via sulfate-respiration. These results demonstrate that syntrophic growth and sulfate-respiration use largely independent energy generation pathways and imply that understanding of microbial processes sustaining nutrient cycling must consider lifestyles not captured in pure culture.

  2. DNA Damage Induced by Low-Energy Electrons: Electron Transfer and Diffraction

    SciTech Connect (OSTI)

    Zheng Yi; Wagner, J. Richard; Sanche, Leon [Groupe de Recherche en Sciences des Radiations, Faculte de Medecine, Universite de Sherbrooke, Sherbrooke, QC J1H 5N4 (Canada)

    2006-05-26T23:59:59.000Z

    Thin films of the short single strand of DNA, GCAT, in which guanine (G) or adenine (A) have been removed, were bombarded under vacuum by 4 to 15 eV electrons. The fragments corresponding to base release and strand breaks (SB) were analyzed by high performance liquid chromatography and their yields compared with those obtained from unmodified GCAT. From such a comparison, it is shown that, using GCAT as a model system (1) most SB result from electron capture by DNA bases followed by electron transfer to the phosphate group and (2) the initial capture probability depends on the coherence of the electron wave within the tetramer.

  3. Transmission of Megawatt Relativistic Electron Beams through Millimeter Apertures

    E-Print Network [OSTI]

    Alarcon, R.

    High-power, relativistic electron beams from energy-recovering linacs have great potential to realize new experimental paradigms for pioneering innovation in fundamental and applied research. A major design consideration ...

  4. Reduced density matrix hybrid approach: Application to electronic energy transfer

    SciTech Connect (OSTI)

    Berkelbach, Timothy C.; Reichman, David R. [Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027 (United States); Markland, Thomas E. [Department of Chemistry, Stanford University, 333 Campus Drive, Stanford, California 94305 (United States)

    2012-02-28T23:59:59.000Z

    Electronic energy transfer in the condensed phase, such as that occurring in photosynthetic complexes, frequently occurs in regimes where the energy scales of the system and environment are similar. This situation provides a challenge to theoretical investigation since most approaches are accurate only when a certain energetic parameter is small compared to others in the problem. Here we show that in these difficult regimes, the Ehrenfest approach provides a good starting point for a dynamical description of the energy transfer process due to its ability to accurately treat coupling to slow environmental modes. To further improve on the accuracy of the Ehrenfest approach, we use our reduced density matrix hybrid framework to treat the faster environmental modes quantum mechanically, at the level of a perturbative master equation. This combined approach is shown to provide an efficient and quantitative description of electronic energy transfer in a model dimer and the Fenna-Matthews-Olson complex and is used to investigate the effect of environmental preparation on the resulting dynamics.

  5. Reduced density matrix hybrid approach: Application to electronic energy transfer

    E-Print Network [OSTI]

    Timothy C. Berkelbach; Thomas E. Markland; David R. Reichman

    2011-11-21T23:59:59.000Z

    Electronic energy transfer in the condensed phase, such as that occurring in photosynthetic complexes, frequently occurs in regimes where the energy scales of the system and environment are similar. This situation provides a challenge to theoretical investigation since most approaches are accurate only when a certain energetic parameter is small compared to others in the problem. Here we show that in these difficult regimes, the Ehrenfest approach provides a good starting point for a dynamical description of the energy transfer process due to its ability to accurately treat coupling to slow environmental modes. To further improve on the accuracy of the Ehrenfest approach, we use our reduced density matrix hybrid framework to treat the faster environmental modes quantum mechanically, at the level of a perturbative master equation. This combined approach is shown to provide an efficient and quantitative description of electronic energy transfer in a model dimer and the Fenna-Matthews-Olson complex and is used to investigate the effect of environmental preparation on the resulting dynamics.

  6. Transmission of Megawatt Relativistic Electron Beams Through Millimeter Apertures

    SciTech Connect (OSTI)

    Arizona State University; Arizona State University; JLAB; MIT; College of William and Mary, JLAB; MIT; JLAB; JLAB; MIT; MIT; Hampton University; MIT; JLAB; MIT; JLAB; MIT; MIT; JLAB; MIT; JLAB; JLAB

    2013-10-01T23:59:59.000Z

    High power, relativistic electron beams from energy recovery linacs have great potential to realize new experimental paradigms for pioneering research in fundamental and applied research. A major design consideration for these new generation of experimental capabilities is the understanding of the halo associated with these bright, intense beams. In this Letter, we report on measurements performed using the 100 MeV, 430 kWatt CW electron beam from the energy recovery linac at the Jeff#11;erson Laboratory's Free Electron Laser facility as it traversed a set of small apertures in a 127 mm long aluminum block. Thermal measurements of the block together with neutron measurements near the beam-target interaction point yielded a consistent understanding of the beam losses. These were determined to be 3 ppm through a 2 mm diameter aperture and were maintained during a 7 hour continuous run.

  7. Modeling biofilms with dual extracellular electron transfer mechanisms

    SciTech Connect (OSTI)

    Renslow, Ryan S.; Babauta, Jerome T.; Kuprat, Andrew P.; Schenk, Jim; Ivory, Cornelius; Fredrickson, Jim K.; Beyenal, Haluk

    2013-11-28T23:59:59.000Z

    Electrochemically active biofilms have a unique form of respiration in which they utilize solid external materials as their terminal electron acceptor for metabolism. Currently, two primary mechanisms have been identified for long-range extracellular electron transfer (EET): a diffusion- and a conduction-based mechanism. Evidence in the literature suggests that some biofilms, particularly Shewanella oneidensis, produce components requisite for both mechanisms. In this study, a generic model is presented that incorporates both diffusion- and conduction-based mechanisms and allows electrochemically active biofilms to utilize both simultaneously. The model was applied to Shewanella oneidensis and Geobacter sulfurreducens biofilms using experimentally generated data found the literature. Our simulation results showed that 1) biofilms having both mechanisms available, especially if they can interact, may have metabolic advantage over biofilms that can use only a single mechanism; 2) the thickness of Geobacter sulfurreducens biofilms is likely not limited by conductivity; 3) accurate intrabiofilm diffusion coefficient values are critical for current generation predictions; and 4) the local biofilm potential and redox potential are two distinct measurements and cannot be assumed to have identical values. Finally, we determined that cyclic and squarewave voltammetry are currently not good tools to determine the specific percentage of extracellular electron transfer mechanisms used by biofilms. The developed model will be a critical tool in designing experiments to explain EET mechanisms.

  8. Measurements of electron cloud density in the CERN Super Proton Synchrotron with the microwave transmission method

    E-Print Network [OSTI]

    Federmann, S; Mahner, E

    2011-01-01T23:59:59.000Z

    The electron cloud effect can pose severe performance limitations in high-energy particle accelerators as the CERN Super Proton Synchrotron (SPS). Mitigation techniques such as vacuum chamber thin film coatings with low secondary electron yields (SEY < 1.3) aim to reduce or even suppress this effect. The microwave transmission method, developed and first applied in 2003 at the SPS, measures the integrated electron cloud density over a long section of an accelerator. This paper summarizes the theory and measurement principle and describes the new SPS microwave transmission setup used to study the electron cloud mitigation of amorphous carbon coated SPS dipole vacuum chambers. Comparative results of carbon coated and bare stainless steel dipole vacuum chambers are given for the beam with nominal LHC 25 ns bunch-to-bunch spacing in the SPS and the electron cloud density is derived.

  9. Light induced electron transfer reactions of metal complexes

    SciTech Connect (OSTI)

    Sutin, N.; Creutz, C.

    1980-01-01T23:59:59.000Z

    Properties of the excited states of tris(2,2'-bipyridine) and tris(1,10-phenanthroline) complexes of chromium(III), iron(II), ruthenium(II), osmium(II), rhodium(III), and iridium(III) are described. The electron transfer reactions of the ground and excited states are discussed and interpreted in terms of the driving force for the reaction and the distortions of the excited states relative to the corresponding ground states. General considerations relevant to the conversion of light into chemical energy are presented and progress in the use of polypyridine complexes to effect the light decomposition of water into hydrogen and oxygen is reviewed.

  10. Photoinduced electron transfer in perylene-TiO2 nanoassemblies

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)IntegratedSpeeding accessPeptoid NanosheetsStudying thePhotoinduced electron transfer

  11. The influence of diffusion on photoinduced electron transfer and geminate recombination

    E-Print Network [OSTI]

    Fayer, Michael D.

    in some electron transfer reactions).' Many bio- chemical charge-transfer reactions take place in fluid media whose properties govern life processes.' Before current can flow in a fuel cell, the fuel has to diffuse to an electrode for electron transfer to occur and the spent fuel must diffuse away

  12. Determination of the electronics transfer function for current transient measurements

    E-Print Network [OSTI]

    Christian Scharf; Robert Klanner

    2014-10-02T23:59:59.000Z

    We describe a straight-forward method for determining the transfer function of the readout of a sensor for the situation in which the current transient of the sensor can be precisely simulated. The method relies on the convolution theorem of Fourier transforms. The specific example is a planar silicon pad diode connected with a 50 $\\Omega $ cable to an amplifier followed by a 5 GS/s sampling oscilloscope. The charge carriers in the sensor were produced by picosecond lasers with light of wavelengths of 675 and 1060 nm. The transfer function is determined from the 1060 nm data with the pad diode biased at 1000 V. It is shown that the simulated sensor response convoluted with this transfer function provides an excellent description of the measured transients for the laser light of both wavelengths, at voltages 50 V above the depletion voltage of about 90 V up to the maximum applied voltage of 1000 V. The method has been developed for the precise measurement of the dependence of the drift velocity of electrons and holes in high-ohmic silicon on crystal orientation, electric field and temperature. It can also be applied for the analysis of transient-current measurements of radiation-damaged solid state sensors, as long as sensors properties, like high-frequency capacitance, are not too different.

  13. Aqueous systems from first-principles : structure, dynamics and electron-transfer reactions

    E-Print Network [OSTI]

    Sit, Patrick Hoi Land

    2006-01-01T23:59:59.000Z

    In this thesis, we show for the first time how it is possible to calculated fully from first-principles the diabatic free-energy surfaces of electron-transfer reactions. The excitation energy corresponding to the transfer ...

  14. Proton-coupled electron transfer reactions in solution: Molecular dynamics with quantum transitions for model systems

    E-Print Network [OSTI]

    Hammes-Schiffer, Sharon

    Proton-coupled electron transfer reactions in solution: Molecular dynamics with quantum transitions A general minimal model for proton-coupled electron transfer PCET reactions in solution is presented. This model consists of three coupled degrees of freedom that represent an electron, a proton, and a solvent

  15. Noise-assisted quantum electron transfer in photosynthetic complexes

    E-Print Network [OSTI]

    Alexander I. Nesterov; Gennady P. Berman; José Manuel Sánchez Martínez; Richard T. Sayre

    2013-04-30T23:59:59.000Z

    Electron transfer (ET) between primary electron donors and acceptors is modeled in the photosystem II reaction center (RC). Our model includes (i) two discrete energy levels associated with donor and acceptor, interacting through a dipole-type matrix element and (ii) two continuum manifolds of electron energy levels ("sinks"), which interact directly with the donor and acceptor. Namely, two discrete energy levels of the donor and acceptor are embedded in their independent sinks through the corresponding interaction matrix elements. We also introduce classical (external) noise which acts simultaneously on the donor and acceptor (collective interaction). We derive a closed system of integro-differential equations which describes the non-Markovian quantum dynamics of the ET. A region of parameters is found in which the ET dynamics can be simplified, and described by coupled ordinary differential equations. Using these simplified equations, both sharp and flat redox potentials are analyzed. We analytically and numerically obtain the characteristic parameters that optimize the ET rates and efficiency in this system.

  16. Method and apparatus for a high-resolution three dimensional confocal scanning transmission electron microscope

    DOE Patents [OSTI]

    de Jonge, Niels (Oak Ridge, TN) [Oak Ridge, TN

    2010-08-17T23:59:59.000Z

    A confocal scanning transmission electron microscope which includes an electron illumination device providing an incident electron beam propagating in a direction defining a propagation axis, and a precision specimen scanning stage positioned along the propagation axis and movable in at least one direction transverse to the propagation axis. The precision specimen scanning stage is configured for positioning a specimen relative to the incident electron beam. A projector lens receives a transmitted electron beam transmitted through at least part of the specimen and focuses this transmitted beam onto an image plane, where the transmitted beam results from the specimen being illuminated by the incident electron beam. A detection system is placed approximately in the image plane.

  17. Nonadiabatic dynamics for processes involving multiple avoided curve crossings: Double proton transfer and proton-coupled electron transfer

    E-Print Network [OSTI]

    Hammes-Schiffer, Sharon

    Nonadiabatic dynamics for processes involving multiple avoided curve crossings: Double proton transfer and proton-coupled electron transfer reactions Jian-Yun Fang and Sharon Hammes June 1997; accepted 26 August 1997 The extension of the surface hopping method ``molecular dynamics

  18. Photoinitiated proton-coupled electron transfer and radical transport kinetics in class la ribonucleotide reductase

    E-Print Network [OSTI]

    Pizano, Arturo A. (Arturo Alejandro)

    2013-01-01T23:59:59.000Z

    Proton-coupled electron transfer (PCET) is a critical mechanism in biology, underpinning key processes such as radical transport, energy transduction, and enzymatic substrate activation. Ribonucleotide reductases (RNRs) ...

  19. Structural Fluctuations, Spin, Reorganization Energy, and Tunneling Energy Control of Intramolecular Electron Transfer

    E-Print Network [OSTI]

    Kurnikova, Maria

    calculations of electronic couplings, molecular dynamics simulations of molecular geometries, and Poisson exists to interpret electron-transfer (ET) reactions and their dependence upon molecular structure.1Structural Fluctuations, Spin, Reorganization Energy, and Tunneling Energy Control

  20. Thermal transfer structures coupling electronics card(s) to coolant-cooled structure(s)

    DOE Patents [OSTI]

    David, Milnes P; Graybill, David P; Iyengar, Madhusudan K; Kamath, Vinod; Kochuparambil, Bejoy J; Parida, Pritish R; Schmidt, Roger R

    2014-12-16T23:59:59.000Z

    Cooling apparatuses and coolant-cooled electronic systems are provided which include thermal transfer structures configured to engage with a spring force one or more electronics cards with docking of the electronics card(s) within a respective socket(s) of the electronic system. A thermal transfer structure of the cooling apparatus includes a thermal spreader having a first thermal conduction surface, and a thermally conductive spring assembly coupled to the conduction surface of the thermal spreader and positioned and configured to reside between and physically couple a first surface of an electronics card to the first surface of the thermal spreader with docking of the electronics card within a socket of the electronic system. The thermal transfer structure is, in one embodiment, metallurgically bonded to a coolant-cooled structure and facilitates transfer of heat from the electronics card to coolant flowing through the coolant-cooled structure.

  1. On the efficient electron transfer through GEM C.Richter a, #

    E-Print Network [OSTI]

    of the GEM element and the process of electron transport in the gas volume preceding the GEM. The last. In applications where a relatively large number of primary electrons are deposited within the gas volume preceding Abstract The absolute electron transfer efficiency of a gas electron multiplier (GEM) was systematically

  2. A stochastic reorganizational bath model for electronic energy transfer

    E-Print Network [OSTI]

    Takatoshi Fujita; Joonsuk Huh; Alan Aspuru-Guzik

    2014-06-06T23:59:59.000Z

    The fluctuations of optical gap induced by the environment play crucial roles in electronic energy transfer dynamics. One of the simplest approaches to incorporate such fluctuations in energy transfer dynamics is the well known Haken-Strobl-Reineker model, in which the energy-gap fluctuation is approximated as a white noise. Recently, several groups have employed molecular dynamics simulations and excited-state calculations in conjunction to take the thermal fluctuation of excitation energies into account. Here, we discuss a rigorous connection between the stochastic and the atomistic bath models. If the phonon bath is treated classically, time evolution of the exciton-phonon system can be described by Ehrenfest dynamics. To establish the relationship between the stochastic and atomistic bath models, we employ a projection operator technique to derive the generalized Langevin equations for the energy-gap fluctuations. The stochastic bath model can be obtained as an approximation of the atomistic Ehrenfest equations via the generalized Langevin approach. Based on the connection, we propose a novel scheme to correct reorganization effects within the framework of stochastic models. The proposed scheme provides a better description of the population dynamics especially in the regime of strong exciton-phonon coupling. Finally, we discuss the effect of the bath reorganization in the absorption and fluorescence spectra of ideal J-aggregates in terms of the Stokes shifts. For this purpose, we introduce a simple relationship that relates the reorganization contribution to the Stokes shifts - the reorganization shift - to three parameters: the monomer reorganization energy, the relaxation time of the optical gap, and the exciton delocalization length. This simple relationship allows one to classify the origin of the Stokes shifts in molecular aggregates.

  3. 5342 J. Am. Chem. SOC.1993, 115, 5342-5343 Observationof Photoinduced Electron Transfer at a

    E-Print Network [OSTI]

    ) in an aqueous medium can inhibit the back reaction in a photoinduced electron- transfer process: trans-1 not soluble in water.24 Liquid-liquid interfaces were prepared by vigorously mixing a 1 mM solution of l+-BPh4, H., Sigel, A., Eds.; Dekker: New York, 1991; Vol. 27. (6) Electron Transfer in Biology and the Solid

  4. Control of Electron Transfer Rates in Liquid Crystalline Media Mark Lilichenko and Dmitry V. Matyushov*

    E-Print Network [OSTI]

    Matyushov, Dmitry

    The biological environment for photosynthetic charge separa- tion1 and media employed for solar energy conversionControl of Electron Transfer Rates in Liquid Crystalline Media Mark Lilichenko and Dmitry V; In Final Form: December 17, 2002 The solvent reorganization energy of electron-transfer reactions

  5. Thermally Activated, Inverted Interfacial Electron Transfer Kinetics: High Driving Force Reactions between Tin Oxide Nanoparticles and

    E-Print Network [OSTI]

    between Tin Oxide Nanoparticles and Electrostatically-Bound Molecular Reactants Dennis A. Gaal and Joseph: The kinetics and mechanism of fast electron transfer (ET) between tin oxide nanoparticles and electrostatically-order studies establish that, at least in the short time regime, electrons are transferred directly from the tin

  6. Electron Transfer Catalyzed [2 + 2] Cycloreversion of Benzene G. Devi Reddy and Olaf Wiest*

    E-Print Network [OSTI]

    Hudlicky, Tomas

    Electron Transfer Catalyzed [2 + 2] Cycloreversion of Benzene Dimers G. Devi Reddy and Olaf Wiest, Florida 32611-7200 Received December 8, 1998 The catalysis of the [2 + 2] cycloreversion of the anti-o,o-benzene dimer 1 and the syn-o,o- naphthalene-benzene dimer 2 through thermal and photoinduced electron transfer

  7. Reliable strain measurement in transistor arrays by robust scanning transmission electron microscopy

    SciTech Connect (OSTI)

    Kim, Suhyun; Kim, Joong Jung; Jung, Younheum; Lee, Kyungwoo; Byun, Gwangsun; Hwang, KyoungHwan; Lee, Sunyoung; Lee, Kyupil [Memory Analysis Science and Engineering Group, Samsung Electronics, San 16, Hwasung City, Gyeonggi-Do 445-701 (Korea, Republic of)] [Memory Analysis Science and Engineering Group, Samsung Electronics, San 16, Hwasung City, Gyeonggi-Do 445-701 (Korea, Republic of)

    2013-09-15T23:59:59.000Z

    Accurate measurement of the strain field in the channels of transistor arrays is critical for strain engineering in modern electronic devices. We applied atomic-resolution high-angle annular dark-field scanning transmission electron microscopy to quantitative measurement of the strain field in transistor arrays. The quantitative strain profile over 20 transistors was obtained with high reliability and a precision of 0.1%. The strain field was found to form homogeneously in the channels of the transistor arrays. Furthermore, strain relaxation due to the thin foil effect was quantitatively investigated for thicknesses of 35 to 275 nm.

  8. Extension of Pierce model to multiple transmission lines interacting with an electron beam

    E-Print Network [OSTI]

    Tamma, Venkata Ananth

    2013-01-01T23:59:59.000Z

    A possible route towards achieving high power microwave devices is through the use of novel slow-wave structures employing multiple coupled transmission lines (MTLs) whose behavior when coupled to electron beams have not been sufficiently explored. We present the extension of the one-dimensional linearized Pierce theory to MTLs coupled to a single electron beam. We develop multiple formalisms to calculate the k-{\\omega} dispersion relation of the system and find that the existence of a growing wave solution is always guaranteed if the electron propagation constant is larger than or equal to the largest propagation constant of the MTL system. We verify our findings with illustrative examples which bring to light unique properties of the system in which growing waves were found to exist within finite bands of the electron propagation constant and discuss possible approach to improve the gain. By treating the beam-MTL interaction as distributed dependent current generators in the MTL, we derive relations charact...

  9. The application of Graphene as a sample support in Transmission Electron Microscopy

    E-Print Network [OSTI]

    Pantelic, R S; Kaiser, U; Stahlberg, H

    2012-01-01T23:59:59.000Z

    Transmission electron microscopy has witnessed rampant development and surging point resolution over the past few years. The improved imaging performance of modern electron microscopes shifts the bottleneck for image contrast and resolution to sample preparation. Hence, it is increasingly being realized that the full potential of electron microscopy will only be realized with the optimization of current sample preparation techniques. Perhaps the most recognized issues are background signal and noise contributed by sample supports, sample charging and instability. Graphene provides supports of single atom thickness, extreme physical stability, periodic structure, and ballistic electrical conductivity. As an increasing number of applications adapting graphene to their benefit emerge, we discuss the unique capabilities afforded by the use of graphene as a sample support for electron microscopy.

  10. A Comparison of Electron-Transfer Dynamics inIonic Liquids and Neutral Solvents

    SciTech Connect (OSTI)

    Wishart J. F.; Lee, H.Y.; Issa, J.B.; Isied, S.S.; Castner, Jr., E.W.; Pan, Y.; Hussey, C.L.; Lee, K.S.

    2012-03-01T23:59:59.000Z

    The effect of ionic liquids on photoinduced electron-transfer reactions in a donor-bridge-acceptor system is examined for two ionic liquid solvents, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide and tributylmethylammonium bis(trifluoromethylsulfonyl)amide. The results are compared with those for the same system in methanol and acetonitrile solution. Electron-transfer rates were measured using time-resolved fluorescence quenching for the donor-bridge-acceptor system comprising a 1-N,1-N-dimethylbenzene-1,4-diamine donor, a proline bridge, and a coumarin 343 acceptor. The photoinduced electron-transfer processes are in the inverted regime (-{Delta}G > {lambda}) in all four solvents, with driving forces of -1.6 to -1.9 eV and estimated reorganization energies of about 1.0 eV. The observed electron-transfer kinetics have broadly distributed rates that are generally slower in the ionic liquids compared to the neutral solvents, which also have narrower rate distributions. To describe the broad distributions of electron-transfer kinetics, we use two different models: a distribution of exponential lifetimes and a discrete sum of exponential lifetimes. Analysis of the donor-acceptor electronic coupling shows that for ionic liquids this intramolecular electron-transfer reaction should be treated using a solvent-controlled electron-transfer model.

  11. Photoinduced bimolecular electron transfer kinetics in small unilamellar vesicles

    SciTech Connect (OSTI)

    Choudhury, Sharmistha Dutta; Kumbhakar, Manoj; Nath, Sukhendu; Pal, Haridas [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)

    2007-11-21T23:59:59.000Z

    Photoinduced electron transfer (ET) from N,N-dimethylaniline to some coumarin derivatives has been studied in small unilamellar vesicles (SUVs) of the phospholipid, DL-{alpha}-dimyristoyl-phosphatidylcholine, using steady-state and time-resolved fluorescence quenching, both below and above the phase transition temperature of the vesicles. The primary interest was to examine whether Marcus inversion [H. Sumi and R. A. Marcus, J. Chem. Phys. 84, 4894 (1986)] could be observed for the present ET systems in these organized assemblies. The influence of the topology of SUVs on the photophysical properties of the reactants and consequently on their ET kinetics has also been investigated. Absorption and fluorescence spectral data of the coumarins in SUVs and the variation of their fluorescence decays with temperature indicate that the dyes are localized in the bilayer of the SUVs. Time-resolved area normalized emission spectra analysis, however, reveals that the dyes are distributed in two different microenvironments in the SUVs, which we attribute to the two leaflets of the bilayer, one toward bulk water and the other toward the inner water pool. The microenvironments in the two leaflets are, however, not indicated to be that significantly different. Time-resolved anisotropy decays were biexponential for all the dyes in SUVs, and this has been interpreted in terms of the compound motion model according to which the dye molecules can experience a fast wobbling-in-cone type of motion as well as a slow overall rotating motion of the cone containing the molecule. The expected bimolecular diffusion-controlled rates in SUVs, as estimated by comparing the microviscosities in SUVs (determined from rotational correlation times) and that in acetonitrile solution, are much slower than the observed fluorescence quenching rates, suggesting that reactant diffusion (translational) does not play any role in the quenching kinetics in the present systems. Accordingly, clear inversions are observed in the correlation of the fluorescence quenching rate constants k{sub q} with the free energy change, {delta}G{sup 0} of the reactions. However, the coumarin dyes, C152 and C481 (cf. Scheme 1), show unusually high k{sub q} values and high activation barriers, which is not expected from Marcus ET theory. This unusual behavior is explained on the basis of participation of the twisted intramolecular charge transfer states of these two dyes in the ET kinetics.

  12. Coherent transfer of light polarization to electron spins in a semiconductor

    E-Print Network [OSTI]

    Hideo Kosaka; Hideki Shigyou; Yasuyoshi Mitsumori; Yoshiaki Rikitake; Hiroshi Imamura; Takeshi Kutsuwa; Koichiro Arai; Keiichi Edamatsu

    2007-10-20T23:59:59.000Z

    We demonstrate that the superposition of light polarization states is coherently transferred to electron spins in a semiconductor quantum well. By using time-resolved Kerr rotation we observe the initial phase of Larmor precession of electron spins whose coherence is transferred from light. To break the electron-hole spin entanglement, we utilized the big discrepancy between the transverse g-factors of electrons and light holes. The result encourages us to make a quantum media converter between flying photon qubits and stationary electron spin qubits in semiconductors.

  13. Study of intermediates from transition metal excited-state electron-transfer reactions

    SciTech Connect (OSTI)

    Hoffman, M.Z.

    1992-07-31T23:59:59.000Z

    Conventional and fast-kinetics techniques of photochemistry, photophysics, radiation chemistry, and electrochemistry were used to study the intermediates involved in transition metal excited-state electron-transfer reactions. These intermediates were excited state of Ru(II) and Cr(III) photosensitizers, their reduced forms, and species formed in reactions of redox quenchers and electron-transfer agents. Of particular concern was the back electron-transfer reaction between the geminate pair formed in the redox quenching of the photosensitizers, and the dependence of its rate on solution medium and temperature in competition with transformation and cage escape processes. (DLC)

  14. THE JOURNAL OF CHEMICAL PHYSICS 138, 114105 (2013) Reorganization energy of electron transfer processes in ionic fluids

    E-Print Network [OSTI]

    Song, Xueyu

    2013-01-01T23:59:59.000Z

    solutions. Thus any reliable theoretical understanding of electron transfer reactions in ionic fluidsTHE JOURNAL OF CHEMICAL PHYSICS 138, 114105 (2013) Reorganization energy of electron transfer; published online 15 March 2013) The reorganization energy of electron transfer processes in ionic fluids

  15. Model Proton-Coupled Electron Transfer Reactions in Solution: Predictions of Rates, Mechanisms, and Kinetic Isotope Effects

    E-Print Network [OSTI]

    Hammes-Schiffer, Sharon

    Model Proton-Coupled Electron Transfer Reactions in Solution: Predictions of Rates, Mechanisms isotope effects for proton-coupled electron transfer (PCET) reactions. These studies are based, the solvent is represented as a dielectric continuum, and the active electrons and transferring protons

  16. Gas mixing system for imaging of nanomaterials under dynamic environments by environmental transmission electron microscopy

    SciTech Connect (OSTI)

    Akatay, M. Cem [School of Materials Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States)] [School of Materials Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States); Zvinevich, Yury; Ribeiro, Fabio H., E-mail: fabio@purdue.edu, E-mail: estach@bnl.gov [Forney Hall of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Baumann, Philipp [Computer Sciences, University of Applied Sciences of Northeastern Switzerland, 4132 Muttenz, Switzerland and Department of Physics, Yeshiva University, New York, New York 10016 (United States)] [Computer Sciences, University of Applied Sciences of Northeastern Switzerland, 4132 Muttenz, Switzerland and Department of Physics, Yeshiva University, New York, New York 10016 (United States); Stach, Eric A., E-mail: fabio@purdue.edu, E-mail: estach@bnl.gov [Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973 (United States)

    2014-03-15T23:59:59.000Z

    A gas mixing manifold system that is capable of delivering a stable pressure stream of a desired composition of gases into an environmental transmission electron microscope has been developed. The system is designed to provide a stable imaging environment upon changes of either the composition of the gas mixture or upon switching from one gas to another. The design of the system is described and the response of the pressure inside the microscope, the sample temperature, and sample drift in response to flow and composition changes of the system are reported.

  17. Structural defects in GaN revealed by Transmission Electron Microscopy

    SciTech Connect (OSTI)

    Liliental-Weber, Zuzanna

    2014-04-18T23:59:59.000Z

    This paper reviews the various types of structural defects observed by Transmission Electron Microscopy in GaN heteroepitaxial layers grown on foreign substrates and homoepitaxial layers grown on bulk GaN substrates. The structural perfection of these layers is compared to the platelet self-standing crystals grown by High Nitrogen Pressure Solution. Defects in undoped and Mg doped GaN are discussed. Some models explaining the formation of inversion domains in heavily Mg doped layers that are possible defects responsible for the difficulties of p-doping in GaN are also reviewed.

  18. Gene expression and deletion analysis of mechanisms for electron transfer from electrodes to Geobacter sulfurreducens

    E-Print Network [OSTI]

    Lovley, Derek

    transfer to electrodes. Keywords: microbial fuel cell, Geobacter sulfurreducens, cathode, electron donor. Surprisingly, genes for putative cell-electrode connections, such as outer-surface cytochromes and pili, which emerging area in microbe-electrode interactio

  19. Vectorial electron transfer in spatially ordered arrays. Progress report, January 1992--January 1993

    SciTech Connect (OSTI)

    Fox, M.A.

    1993-02-01T23:59:59.000Z

    Progress was made on synthesis of new materials for directional electron transfer (block copolymers and helical oligopeptides), preparation and characterization of anisotropic composites bearing organics and inorganics, electrocatalysis (redox-activated catalysts), and surface modifications of metals and semiconductors.

  20. Nonadiabatic electron transfer in the condensed phase, via semiclassical and Langevin equation approach

    E-Print Network [OSTI]

    Song, XiaoGeng, Ph. D. Massachusetts Institute of Technology

    2009-01-01T23:59:59.000Z

    In this dissertation, we discuss two methods developed during my PhD study to simulate electron transfer systems. The first method, the semi-classical approximation, is derived from the stationary phase approximation to ...

  1. Room-Temperature Gas Sensing Based on Electron Transfer between Discrete Tin Oxide Nanocrystals and

    E-Print Network [OSTI]

    Chen, Junhong

    Room-Temperature Gas Sensing Based on Electron Transfer between Discrete Tin Oxide Nanocrystals and the response time. Rutile-structured tin oxide (SnO2) is an n-type semiconducting material widely used in gas

  2. Ultrafast Energy-Electron Transfer Cascade in a Multichromophoric Light-Harvesting Molecular Square

    E-Print Network [OSTI]

    van Stokkum, Ivo

    and electron-transfer pathways, and chromophoric heterogeneity. Temperature-dependent time-resolved emission in the fields of molecular recognition,9,10 sensing,6,9 catalysis,11 and electrochemical or photochemical

  3. Photochemical ribonucleotide reductase for the study of proton-coupled electron transfer

    E-Print Network [OSTI]

    Reece, Steven Y., 1980-

    2007-01-01T23:59:59.000Z

    Charge transport and catalysis in enzymes often rely on amino acid radicals as intermediates. The generation and transport of these radicals are synonymous with proton-coupled electron transfer (PCET), which intrinsically ...

  4. Proton-coupled electron transfer : from basic principles to small molecule activation

    E-Print Network [OSTI]

    Rosenthal, Joel, 1979-

    2007-01-01T23:59:59.000Z

    Proton-coupled electron transfer (PCET) is the basic mechanism for bioenergetic conversion. Hallmark examples of such reactivities include water oxidation which is coupled to photosynthesis and oxygen reduction which is ...

  5. The Roles of Outer Membrane Cytochromes of Shewanella and Geobacter in Extracellular Electron Transfer

    SciTech Connect (OSTI)

    Shi, Liang; Richardson, David; Wang, Zheming; Kerisit, Sebastien N.; Rosso, Kevin M.; Zachara, John M.; Fredrickson, Jim K.

    2009-08-01T23:59:59.000Z

    As key components of the electron transfer (ET) pathways used for dissimilatory reduction of solid iron [Fe(III)] and manganese [Mn(IV)] (hydr)oxides, outer membrane cytochromes MtrC and OmcA of Shewanella oneidensis MR-1 and OmcE and OmcS of Geobacter sulfurreducens mediate ET reactions extracellularly. Cell surface-exposed MtrC and OmcA can transfer electrons directly to the metal oxides. S. oneidensis MR-1 cells also secrete flavins that can facilitate ET to the oxides. The secreted flavins are thought to serve either as chelators that form soluble Fe(III)/Mn(IV)-flavin complexes or as electron shuttles that ferry the electrons from cell-associated ET proteins to the metal oxides. Cell-surface localization may also permit MtrC and OmcA to transfer electrons extracellularly to either flavin-chelated Fe(III)/Mn(IV) or oxidized flavins. OmcE and OmcS are proposed to be located on the Geobacter cell surface where they are believed to function as the intermediates to relay electrons to type IV pili, which are then hypothesized to transfer electrons directly to the metal oxides. Thus, cell surface-localization positions these outer membrane cytochromes to transfer electrons to Fe(III)/Mn(IV) oxides external to the bacterial cells either directly, indirectly, or both, demonstrating a common strategy shared by Shewanella and Geobacter for extracellular reduction of the oxides.

  6. Exciton/Charge-transfer Electronic Couplings in Organic Semiconductors

    E-Print Network [OSTI]

    Difley, Seth

    Charge transfer (CT) states and excitons are important in energy conversion processes that occur in organic light emitting devices (OLEDS) and organic solar cells. An ab initio density functional theory (DFT) method for ...

  7. Microscopic mechanism of electron transfer through the hydrogen bonds between carboxylated alkanethiol molecules connected to gold electrodes

    SciTech Connect (OSTI)

    Li, Yang; Tu, Xingchen; Wang, Minglang; Wang, Hao; Hou, Shimin, E-mail: smhou@pku.edu.cn [Centre for Nanoscale Science and Technology, Key Laboratory for the Physics and Chemistry of Nanodevices, Department of Electronics, Peking University, Beijing 100871 (China); Sanvito, Stefano [School of Physics, AMBER and CRANN Institute, Trinity College, Dublin 2 (Ireland)

    2014-11-07T23:59:59.000Z

    The atomic structure and the electron transfer properties of hydrogen bonds formed between two carboxylated alkanethiol molecules connected to gold electrodes are investigated by employing the non-equilibrium Green's function formalism combined with density functional theory. Three types of molecular junctions are constructed, in which one carboxyl alkanethiol molecule contains two methylene, –CH{sub 2}, groups and the other one is composed of one, two, or three –CH{sub 2} groups. Our calculations show that, similarly to the cases of isolated carboxylic acid dimers, in these molecular junctions the two carboxyl, –COOH, groups form two H-bonds resulting in a cyclic structure. When self-interaction corrections are explicitly considered, the calculated transmission coefficients of these three H-bonded molecular junctions at the Fermi level are in good agreement with the experimental values. The analysis of the projected density of states confirms that the covalent Au–S bonds localized at the molecule-electrode interfaces and the electronic coupling between –COOH and S dominate the low-bias junction conductance. Following the increase of the number of the –CH{sub 2} groups, the coupling between –COOH and S decreases deeply. As a result, the junction conductance decays rapidly as the length of the H-bonded molecules increases. These findings not only provide an explanation to the observed distance dependence of the electron transfer properties of H-bonds, but also help the design of molecular devices constructed through H-bonds.

  8. Building model systems to understand Proton-Coupled Electron Transfer in heme : spectroscopic investigation of charge transfer to axially bound diimide acceptors

    E-Print Network [OSTI]

    Hanson, Christina J

    2013-01-01T23:59:59.000Z

    Proton-Coupled Electron Transfer (PCET) is an important mechanistic motif in chemistry, which allows for efficient charge transport in many biological systems. We seek to understand how the proton and electron motions are ...

  9. Intramolecular, photoinduced electron transfer in ruthenium(II) bipyridine-quinone complexes

    SciTech Connect (OSTI)

    Opperman, K.A.; Mecklenburg, S.L.; Meyer, T.J. [Univ. of North Carolina, Chapel Hill, NC (United States)

    1994-11-09T23:59:59.000Z

    Adsorption spectroscopy and transient emission spectroscopy were used to follow intramolecular electron transfer quenching after metal-to-ligand charge transfer (MLCT) excitation of Ru(II)bipyridine-quinone complexes. Studies of various N-((4{prime}methyl-2-2{prime}-bipyridyl)-4-methyl)-9,10-anthraquinone-2-carboxamide (bpy-AQ) complexes, revealed that these complexes quench by rapid electron transfer from ligand radical excited states to the metal center. A donor-chromophore-acceptor complex with the bpy-AQ ligand and the (10-[4({prime}-methyl-2,2{prime}-bipyridin-4-yl)methylphenothiazine)] (bpy-PTZ) ligand displays redox separation on excitation.

  10. One-Electron-Transfer Reactions of Polychlorinated Ethylenes...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ab initio electronic structure methods, by providing experimentally inaccessible thermodynamics properties and activation energies, are able to sort out possible reactions...

  11. Modeling biofilms with dual extracellular electron transfer mechanisms...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    a unique form of respiration in which they utilize solid external materials as their terminal electron acceptor for metabolism. Currently, two primary mechanisms have been...

  12. Non-adiabatic molecular dynamics simulation of ultrafast solar cell electron transfer

    E-Print Network [OSTI]

    confinement devices [1­5]. Solar cells of the Graetzel type [6,7] are based on dye sensitized nanocrystalline in solar cells, photocatalysis and photoelectrolysis. The electronic structure of the dye cell; Ultrafast electron transfer; Non-adiabatic molecular dynamics simulation; Dye sensitized titanium

  13. Long-Range Electronic-to-Vibrational Energy Transfer from Nanocrystals to Their Surrounding Matrix Environment

    E-Print Network [OSTI]

    Rabani, Eran

    for the analysis, control, and optimization of energy storage and disposal in chemistry, physics, material sci radiationless electronic-to-vibrational energy conversion and vibrational energy exchange, which are centralLong-Range Electronic-to-Vibrational Energy Transfer from Nanocrystals to Their Surrounding Matrix

  14. Energetics of Electron-Transfer Reactions in Soft Condensed

    E-Print Network [OSTI]

    Matyushov, Dmitry

    scales. Thermodynamics of activation is related to the length scale of microscopic interactions reflected barrier when the time scale of the reaction is comparable to the relaxation time of the solvent-transfer reactions (see reviews in refs 1-4). Recent advances in spectroscopic techniques examining the dynamics

  15. Transmission electron microscopy investigation of acicular ferrite precipitation in {gamma}'-Fe{sub 4}N nitride

    SciTech Connect (OSTI)

    Xiong, X.C., E-mail: xiaochuan.xiong@sjtu.edu.cn [Shanghai Key Laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Institut Jean Lamour, UMR 7198 CNRS, Nancy-Universite, UPV-Metz, Ecole des Mines de Nancy, Parc de Saurupt CS 14234, F-54042 Nancy Cedex (France); Redjaimia, A. [Institut Jean Lamour, UMR 7198 CNRS, Nancy-Universite, UPV-Metz, Ecole des Mines de Nancy, Parc de Saurupt CS 14234, F-54042 Nancy Cedex (France); Goune, M. [Institut Jean Lamour, UMR 7198 CNRS, Nancy-Universite, UPV-Metz, Ecole des Mines de Nancy, Parc de Saurupt CS 14234, F-54042 Nancy Cedex (France); ArcelorMittal SA, Voie Romaine, BP 30320, F-57283 Maizieres-les-Metz (France)

    2010-11-15T23:59:59.000Z

    Acicular-shaped crystals precipitate from {gamma}'-Fe{sub 4}N nitride in an iron-nitrogen alloy and were identified by electron microdiffraction as {alpha}-ferrite. Acicular ferrite develops both the Nishiyama-Wassermann and the Kurdjumov-Sachs orientation relationships with {gamma}'-Fe{sub 4}N nitride. These orientation relationships were discussed in terms of the symmetry theory. The driving force for acicular ferrite formation was related to the increasing nitrogen content of {gamma}'-Fe{sub 4}N, in equilibrium with {alpha}-ferrite, with decreasing temperature. The passage from lamellar to acicular structure in Fe-N system was proposed. - Research Highlights: {yields} Acicular crystals precipitate from pearlitic{gamma}'-Fe{sub 4}N nitride in an iron-nitrogen alloy and were identified by electron microdiffraction as acicular ferrite. {yields} The crystal structure, orientation relationships with the matrix and morphologies of acicular ferrite, were studied by transmission electron microscopy. {yields} The driving force for the formation of acicular ferrite is related to the temperature dependence of nitrogen content of {gamma}'-Fe{sub 4}N, in equilibrium with ferrite. {yields} The passage from the pearlitic structure to the acicular structure in the present iron-nitrogen alloy was proposed.

  16. Measured Radiation and Background Levels During Transmission of Megawatt Electron Beams Through Millimeter Apertures

    E-Print Network [OSTI]

    Alarcon, R; Benson, S V; Bertozzi, W; Boyce, J R; Cowan, R; Douglas, D; Evtushenko, P; Fisher, P; Ihloff, E; Kalantarians, N; Kelleher, A; Kossler, W J; Legg, R; Long, E; Milner, R G; Neil, G R; Ou, L; Schmookler, B; Tennant, C; Tschalaer, C; Williams, G P; Zhang, S

    2013-01-01T23:59:59.000Z

    We report measurements of photon and neutron radiation levels observed while transmitting a 0.43 MW electron beam through millimeter-sized apertures and during beam-off, but accelerating gradient RF-on, operation. These measurements were conducted at the Free-Electron Laser (FEL) facility of the Jefferson National Accelerator Laboratory (JLab) using a 100 MeV electron beam from an energy-recovery linear accelerator. The beam was directed successively through 6 mm, 4 mm, and 2 mm diameter apertures of length 127 mm in aluminum at a maximum current of 4.3 mA (430 kW beam power). This study was conducted to characterize radiation levels for experiments that need to operate in this environment, such as the proposed DarkLight Experiment. We find that sustained transmission of a 430 kW continuous-wave (CW) beam through a 2 mm aperture is feasible with manageable beam-related backgrounds. We also find that during beam-off, RF-on operation, multipactoring inside the niobium cavities of the accelerator cryomodules is ...

  17. Measured Radiation and Background Levels During Transmission of Megawatt Electron Beams Through Millimeter Apertures

    SciTech Connect (OSTI)

    Alarcon, Ricardo [Arizona State University, Glendale, AZ (United States); Balascuta, S. [Arizona State University, Glendale, AZ (United States); Benson, Stephen V. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Bertozzi, William [Massachusetts Institute of Technology, Cambridge, MA (United States); Boyce, James R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Cowan, Ray [Massachusetts Institute of Technology, Cambridge, MA (United States); Douglas, David R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Evtushenko, Pavel [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Fisher, P. [Massachusetts Institute of Technology, Cambridge, MA (United States); Ihloff, Ernest E. [Hampton University, Hampton, VA (United States); Kalantarians, Narbe [Hampton University, Hampton, VA (United States); Kelleher, Aidan Michael [Massachusetts Institute of Technology, Cambridge, MA (United States); Krossler, W. J. [William and Mary College, Williamsburg, VA (United States); Legg, Robert A. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Long, Elena [University of New Hampshire, Durham, NH (United States); Milner, Richard [Massachusetts Institute of Technology, Cambridge, MA (United States); Neil, George R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Ou, Longwu [Massachusetts Institute of Technology, Cambridge, MA (United States); Schmookler, Barack Abraham [Massachusetts Institute of Technology, Cambridge, MA (United States); Tennant, Christopher D. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Tschalar, C. [Massachusetts Institute of Technology, Cambridge, MA (United States); Williams, Gwyn P. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Zhang, Shukui [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2013-11-01T23:59:59.000Z

    We report measurements of photon and neutron radiation levels observed while transmitting a 0.43 MW electron beam through millimeter-sized apertures and during beam-off, but accelerating gradient RF-on, operation. These measurements were conducted at the Free-Electron Laser (FEL) facility of the Jefferson National Accelerator Laboratory (JLab) using a 100 MeV electron beam from an energy-recovery linear accelerator. The beam was directed successively through 6 mm, 4 mm, and 2 mm diameter apertures of length 127 mm in aluminum at a maximum current of 4.3 mA (430 kW beam power). This study was conducted to characterize radiation levels for experiments that need to operate in this environment, such as the proposed DarkLight Experiment. We find that sustained transmission of a 430 kW continuous-wave (CW) beam through a 2 mm aperture is feasible with manageable beam-related backgrounds. We also find that during beam-off, RF-on operation, multipactoring inside the niobium cavities of the accelerator cryomodules is the primary source of ambient radiation when the machine is tuned for 130 MeV operation.

  18. Rendering graphene supports hydrophilic with non-covalent aromatic functionalization for transmission electron microscopy

    SciTech Connect (OSTI)

    Pantelic, Radosav S., E-mail: pantelic@imbb.forth.gr [National Cancer Institute, 50 South Drive, Building 50, Room 4306, Bethesda, Maryland 20892 (United States); Fu, Wangyang; Schoenenberger, Christian [Department of Physics, University of Basel, Klingelbergstrasse 82, Basel CH-4056 (Switzerland); Stahlberg, Henning [Center for Cellular Imaging and NanoAnalytics, Biozentrum, University of Basel, Mattenstrasse 26, WRO-1058, Basel CH-4058 (Switzerland)

    2014-03-31T23:59:59.000Z

    Amorphous carbon films have been routinely used to enhance the preparation of frozen-hydrated samples for transmission electron microscopy (TEM), either in retaining protein concentration, providing mechanical stability or dissipating sample charge. However, strong background signal from the amorphous carbon support obstructs that of the sample, and the insulating properties of thin amorphous carbon films preclude any efficiency in dispersing charge. Graphene addresses the limitations of amorphous carbon. Graphene is a crystalline material with virtually no phase or amplitude contrast and unparalleled, high electrical carrier mobility. However, the hydrophobic properties of graphene have prevented its routine application in Cryo-TEM. This Letter reports a method for rendering graphene TEM supports hydrophilic—a convenient approach maintaining graphene's structural and electrical properties based on non-covalent, aromatic functionalization.

  19. (Formation of fuel via photochemical electron transfer). Annual report

    SciTech Connect (OSTI)

    Jones, G.

    1985-03-04T23:59:59.000Z

    Accomplishments for the past year are reported under the following three main headings, in addition to several other related studies: (1) heterocyclic sulfur compounds which display unusual properties as electron relays which may be important in chemical or fuel forming reactions; (2) cationic dyes which tend to aggregate in interesting ways when bound to polyanion in water; and (3) photochemistry of viologen or pyridinium ions which are complexed or ion-paired with electron donors. A publications update is appended with references cited in this report.

  20. Intramolecular photo-induced electron transfer in a rigid anthracene-N, N-dimethylaniline system

    SciTech Connect (OSTI)

    Minsek, D.W.; Yang, N.C. Yang (Chicago Univ., IL (United States). Dept. of Chemistry); Niemczyk, M.P.; Svec, W.A.; Wasielewski, M.R. (Argonne National Lab., IL (United States))

    1992-01-01T23:59:59.000Z

    2-(N,N-Dimethylamino)-5, 14-ethanopentacene (1) was synthesized and spectroscopic behaviors investigated. Results suggest that 1 undergoes photoinduced electron transfer (PET) in solvents more polar than saturated hydrocarbons. The resulting charge-transfer (CT) state undergoes CT fluorescence efficiently in solvents of low dielectric constants. Fluorescence excitation studies of the CT emission reveal the existence of an EDA interaction in the ground state. The implications of these results are discussed.

  1. Intramolecular photo-induced electron transfer in a rigid anthracene-N, N-dimethylaniline system

    SciTech Connect (OSTI)

    Minsek, D.W.; Yang, N.C. Yang [Chicago Univ., IL (United States). Dept. of Chemistry; Niemczyk, M.P.; Svec, W.A.; Wasielewski, M.R. [Argonne National Lab., IL (United States)

    1992-12-31T23:59:59.000Z

    2-(N,N-Dimethylamino)-5, 14-ethanopentacene (1) was synthesized and spectroscopic behaviors investigated. Results suggest that 1 undergoes photoinduced electron transfer (PET) in solvents more polar than saturated hydrocarbons. The resulting charge-transfer (CT) state undergoes CT fluorescence efficiently in solvents of low dielectric constants. Fluorescence excitation studies of the CT emission reveal the existence of an EDA interaction in the ground state. The implications of these results are discussed.

  2. Study of intermediates from transition metal excited-state electron-transfer reactions

    SciTech Connect (OSTI)

    Hoffman, M.Z.

    1991-12-31T23:59:59.000Z

    During this period, conventional and fast-kinetics techniques of photochemistry, photophysics, radiation chemistry, and electrochemistry were used for the characterization of the intermediates that are involved in transition metal excited-state electron-transfer reactions. The intermediates of interest were the excited states of Ru(II) and Cr(III) photosensitizers, their reduced forms, and the species formed in the reactions of redox quenchers and electron-transfer agents. Of particular concern has been the back electron-transfer reaction between the geminate pair formed in the redox quenching of the photosensitizers, and the dependence of its rate on solution medium and temperature in competition with transformation and cage escape processes.

  3. Photoinduced intramolecular electron transfer in bisviologen-linked porphyrin in acetonitrile

    SciTech Connect (OSTI)

    Hirota, Junji; Okura, Ichiro (Tokyo Inst. of Technology, Yokohama (Japan))

    1993-07-01T23:59:59.000Z

    Bisviologen-linked porphyrin (p-PC[sub 4]V[sub A]C[sub 4]V[sub B]), in which two viologens are connected with porphyrin through methylene chain ([minus](CH[sub 2])[sub 4][minus]) was prepared, and photoinduced singlet state of the porphyrin was quenched by the bonded viologen due to photoinduced intramolecular electron transfer from the photoexcited singlet state of porphyrin in the bonded viologen. The rate constant of the intramolecular electron transfer was 3.10 [times] 10[sup 8] s[sup [minus]1]. The photoexcited triplet state was also quenched by the bonded viologen. The rate constant of intramolecular electron transfer via the photoexcited triplet state was 2.19 [times] 10[sup 5] s[sup [minus]1]. 23 refs., 5 figs., 5 tabs.

  4. Microstructure of highly strained BiFeO{sub 3} thin films: Transmission electron microscopy and electron-energy loss spectroscopy studies

    SciTech Connect (OSTI)

    Heon Kim, Young, E-mail: young.h.kim@kriss.re.kr [Max Planck Institute of Microstructure Physics, Weinberg 2, D-06120 Halle (Germany); Korea Research Institute of Standards and Science (KRISS), Daejeon 305-340 (Korea, Republic of); Bhatnagar, Akash; Pippel, Eckhard; Hesse, Dietrich [Max Planck Institute of Microstructure Physics, Weinberg 2, D-06120 Halle (Germany); Alexe, Marin [Max Planck Institute of Microstructure Physics, Weinberg 2, D-06120 Halle (Germany); University of Warwick, Coventry CV4 7AL, West Midlands (United Kingdom)

    2014-01-28T23:59:59.000Z

    Microstructure and electronic structure of highly strained bismuth ferrite (BiFeO{sub 3}) thin films grown on lanthanum aluminate substrates are studied using high-resolution transmission and scanning transmission electron microscopies and electron energy loss spectroscopy (EELS). Monoclinic and tetragonal phases were observed in films grown at different temperatures, and a mix of both phases was detected in a film grown at intermediate temperature. In this film, a smooth transition of the microstructure was found between the monoclinic and the tetragonal phases. A considerable increase in the c-axis parameters was observed in both phases compared with the rhombohedral bulk phase. The off-center displacement of iron (Fe) ions was increased in the monoclinic phase as compared with the tetragonal phase. EEL spectra show different electronic structures in the monoclinic and the tetragonal phases. These experimental observations are well consistent with the results of theoretical first-principle calculations performed.

  5. The First Events in Photosynthesis: Electronic Coupling and Energy Transfer Dynamics in the Photosynthetic Reaction Center from Rhodobacter sphaeroides

    E-Print Network [OSTI]

    Scherer, Norbert F.

    The First Events in Photosynthesis: Electronic Coupling and Energy Transfer Dynamics in photosynthesis. The reaction center contains six chlorophyll-like pigments arranged with approximate C2 symmetry

  6. STRUCTURAL AND CHEMICAL STUDIES ON CdTe/CdS THIN FILM SOLAR CELLS WITH ANALYTICAL TRANSMISSION ELECTRON MICROSCOPY

    E-Print Network [OSTI]

    Romeo, Alessandro

    at 430 C for 30 min. The cells exhibit an ef£ciency of 12.4 % with a short circuit current density of 23 mA/cm2 and an open circuit voltage of 800 mV. For transmission electron microscopy (TEM) studies

  7. DFT and time-resolved IR investigation of electron transfer between photogenerated 17- and 19-electron organometallic radicals

    SciTech Connect (OSTI)

    Cahoon, James B.; Kling, Matthias F.; Sawyer, Karma R.; Andersen, Lars K.; Harris, Charles B.

    2008-04-30T23:59:59.000Z

    The photochemical disproportionation mechanism of [CpW(CO){sub 3}]{sub 2} in the presence of Lewis bases PR{sub 3} was investigated on the nano- and microsecond time-scales with Step-Scan FTIR time-resolved infrared spectroscopy. 532 nm laser excitation was used to homolytically cleave the W-W bond, forming the 17-electron radicals CpW(CO){sub 3} and initiating the reaction. With the Lewis base PPh{sub 3}, disproportionation to form the ionic products CpW(CO){sub 3}PPh{sub 3}{sup +} and CpW(CO){sub 3}{sup -} was directly monitored on the microsecond time-scale. Detailed examination of the kinetics and concentration dependence of this reaction indicates that disproportionation proceeds by electron transfer from the 19-electron species CpW(CO){sub 3}PPh{sub 3} to the 17-electron species CpW(CO){sub 3}. This result is contrary to the currently accepted disproportionation mechanism which predicts electron transfer from the 19-electron species to the dimer [CpW(CO){sub 3}]{sub 2}. With the Lewis base P(OMe){sub 3} on the other hand, ligand substitution to form the product [CpW(CO){sub 2}P(OMe){sub 3}]{sub 2} is the primary reaction on the microsecond time-scale. Density Functional Theory (DFT) calculations support the experimental results and suggest that the differences in the reactivity between P(OMe){sub 3} and PPh{sub 3} are due to steric effects. The results indicate that radical-to-radical electron transfer is a previously unknown but important process for the formation of ionic products with the organometallic dimer [CpW(CO){sub 3}]{sub 2} and may also be applicable to the entire class of organometallic dimers containing a single metal-metal bond.

  8. Rudolph A. Marcus and His Theory of Electron Transfer Reactions

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Scienceand Requirements RecentlyElectronicResources ResourcesRobust,RomanRoy Primus Roy

  9. SF 9424-EFT;Electronic Funds Transfer Agreement

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Scienceand Requirements RecentlyElectronicResourcesjobs RunningSEAB ReportsFESF/2015)9424-EFT

  10. Electronic Funds Transfer Authorization Form 4/2014

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625govInstrumentstdmadapInactiveVisitingContractElectron-State Hybridization in Heavy-Fermion Systems

  11. Factors influencing quantitative liquid (scanning) transmission...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Factors influencing quantitative liquid (scanning) transmission electron microscopy. Factors influencing quantitative liquid (scanning) transmission electron microscopy. Abstract:...

  12. Laser pulse control of ultrafast heterogeneous electron transfer: A computational study

    E-Print Network [OSTI]

    Röder, Beate

    Laser pulse control of ultrafast heterogeneous electron transfer: A computational study Luxia Wang on ultrafast HET given in Refs. 14­16. In the following we will focus on the case where a tailored laser pulse, Germany Received 31 March 2004; accepted 30 July 2004 Laser pulse control of the photoinduced 90 fs charge

  13. Towards new model systems for the study of proton-coupled electron transfer

    E-Print Network [OSTI]

    Yang, Jay Lee

    2009-01-01T23:59:59.000Z

    Two new model systems for the study of orthogonal proton-coupled electron transfer (PCET) have been developed. The first model system is based on Ru"(HzO)(tpy)(bpy) (tpy = 2,2';6',2"terpyridine, bpy = 2,2'-bipyridine) where ...

  14. Distance Dependence of Electron Transfer in DNA: The Role of the Reorganization Energy and Free Energy

    E-Print Network [OSTI]

    Fayer, Michael D.

    Distance Dependence of Electron Transfer in DNA: The Role of the Reorganization Energy and Free of the solvent reorganization energy and free energy in the heterogeneous DNA environment. DNA is modeled represents water. Model calculations show the importance of including the reorganization energy and the free

  15. Modeling the free energy surfaces of electron transfer in condensed phases

    E-Print Network [OSTI]

    Matyushov, Dmitry

    PROOF COPY 509037JCP Modeling the free energy surfaces of electron transfer in condensed phases analytical solution for the ET free energy surfaces demonstrates the following features: i the range of ET reaction coordinates is limited by a one-sided fluctuation band, ii the ET free energies are infinite

  16. Nonadiabatic electron transfer at the nanoscale tin-oxide semiconductor/aqueous solution interface

    E-Print Network [OSTI]

    published as an Advance Article on the web 28th January 2004 Photo-excitation of chromophoric metal forward and back electron transfer reactions involving molecular dyes and wide bandgap semiconductors words, electro- nic coupling rather than nuclear motion appears to govern the reaction dynamics

  17. Oxygen Isotope Effects as Probes of Electron Transfer Mechanisms and Structures of

    E-Print Network [OSTI]

    Roth, Justine P.

    Oxygen Isotope Effects as Probes of Electron Transfer Mechanisms and Structures of Activated O2, Maryland 21218 RECEIVED ON JULY 26, 2008 C O N S P E C T U S Competitively determined oxygen (18 O) isotope effects can be power- ful probes of chemical and biological transformations involving molec- ular oxygen

  18. Electron-Transfer Studies of a Peroxide Dianion Andrew M. Ullman,

    E-Print Network [OSTI]

    Müller, Peter

    of the ET chemistry of a free peroxide dianion will be useful in studies of metal-air batteries and the use or metal-ion association. This feature has allowed the electron-transfer (ET) kinetics of isolated peroxide or metal ions, and the anion exhibits reversible ET behavior; accordingly, the outer-sphere oxidation

  19. High resolution transmission electron microscopy of melamine-formaldehyde aerogels and silica aerogels

    SciTech Connect (OSTI)

    Ruben, G.C. (Dartmouth Coll., Hanover, NH (United States). Dept. of Biological Sciences)

    1991-09-01T23:59:59.000Z

    The goal of the high resolution transmission electron microscopy (HRTEM) was to image the structure of two tetramethyl orthosilicate (TMOS) and two melamine-formaldehyde (MF) aerogels at the single polymer chain level{sup 1,2}. With this level of structural resolution we hoped to interrelate each aerogel's structure with its physical properties and its method of synthesis. Conventional single-step base catalysed TMOS aerogels show strings of spheroidal particles linked together with minimal necking. The spheroidal particles range from 86--132 {Angstrom} and average 113{plus minus}10 {Angstrom} in diameter{sup 2}. In contrast the TMOS aerogels reported on here were made by a two step method. After extended silica chains are grown in solution under acidic conditions with a substoichiometric amount of water, the reaction is stopped and the methanol hydrolysed from TMOS is removed. Then base catalysis and additional water are added to cause gel formation is a nonalcoholic solvent. The MF aerogels were prepared for HRTEM by fracturing them on a stereo microscope stage with razor knife so that fractured pieces with smooth flat surfaces could be selected for platinum-carbon replication. The two silica (TMOS) aerogels were both transparent and difficult to see. These aerogels were fractured on a stereo microscope stage with tweezers. 6 refs., 4 figs.

  20. TRANSMISSION ELECTRON MICROSCOPY OF Al-RICH SILICATE STARDUST FROM ASYMPTOTIC GIANT BRANCH STARS

    SciTech Connect (OSTI)

    Vollmer, Christian [Institute for Mineralogy, University of Muenster, Correnssstr. 24, D-48149 Muenster (Germany); Hoppe, Peter [Max Planck Institute for Chemistry, Particle Chemistry Department, Hahn-Meitner-Weg 1, D-55128 Mainz (Germany); Brenker, Frank E., E-mail: christian.vollmer@wwu.de [Institute of Geoscience/Mineralogy, Goethe-University Frankfurt, Altenhoeferallee 1, D-60438 Frankfurt (Germany)

    2013-05-20T23:59:59.000Z

    We report on transmission electron microscopy (TEM) investigations of two mineralogically unusual stardust silicates to constrain their circumstellar condensation conditions. Both grains were identified by high spatial resolution nano secondary ion mass spectrometry (NanoSIMS) in the Acfer 094 meteorite, one of the most pristine carbonaceous chondrites available for study. One grain is a highly crystalline, highly refractory (Fe content < 0.5 at%), structurally undisturbed orthopyroxene (MgSiO{sub 3}) with an unusually high Al content (1.8 {+-} 0.5 at%). This is the first TEM documentation of a single crystal pyroxene within the complete stardust silicate data set. We interpret the microstructure and chemistry of this grain as being a direct condensate from a gas of locally non-solar composition (i.e., with a higher-than-solar Al content and most likely also a lower-than-solar Mg/Si ratio) at (near)-equilibrium conditions. From the overabundance of crystalline olivine (six reported grains to date) compared to crystalline pyroxene (only documented as a single crystal in this work) we infer that formation of olivine over pyroxene is favored in circumstellar environments, in agreement with expectations from condensation theory and experiments. The second stardust silicate consists of an amorphous Ca-Si rich material which lacks any crystallinity based on TEM observations in which tiny (<20 nm) hibonite nanocrystallites are embedded. This complex assemblage therefore attests to the fast cooling and rapidly changing chemical environments under which dust grains in circumstellar shells form.

  1. Real-time studies of battery electrochemical reactions inside a transmission electron microscope.

    SciTech Connect (OSTI)

    Leung, Kevin; Hudak, Nicholas S.; Liu, Yang; Liu, Xiaohua H.; Fan, Hongyou; Subramanian, Arunkumar; Shaw, Michael J.; Sullivan, John Patrick; Huang, Jian Yu

    2012-01-01T23:59:59.000Z

    We report the development of new experimental capabilities and ab initio modeling for real-time studies of Li-ion battery electrochemical reactions. We developed three capabilities for in-situ transmission electron microscopy (TEM) studies: a capability that uses a nanomanipulator inside the TEM to assemble electrochemical cells with ionic liquid or solid state electrolytes, a capability that uses on-chip assembly of battery components on to TEM-compatible multi-electrode arrays, and a capability that uses a TEM-compatible sealed electrochemical cell that we developed for performing in-situ TEM using volatile battery electrolytes. These capabilities were used to understand lithiation mechanisms in nanoscale battery materials, including SnO{sub 2}, Si, Ge, Al, ZnO, and MnO{sub 2}. The modeling approaches used ab initio molecular dynamics to understand early stages of ethylene carbonate reduction on lithiated-graphite and lithium surfaces and constrained density functional theory to understand ethylene carbonate reduction on passivated electrode surfaces.

  2. Mechanisms of photoinduced electron transfer: Final report, July 1, 1977-September 30, 1987

    SciTech Connect (OSTI)

    Jones, G. II

    1987-12-01T23:59:59.000Z

    Work which has been conducted under Department of Energy sponsorship over the past ten years at Boston University is described. A general theme for projects which are summarized involves photochemically induced electron transfer reactions for organic compounds. Early studies in the series were directed to the development of new mechanisms for driving isomerization processes which store light energy as latent heat. Other investigations were devoted to an understanding of the dynamics of charge separation for photoexcited (charge-transfer) complexes or ion-pairs. Recent studies focused on the development of charge relays such as dithioethers and viologen or pyridinium ions, the electron transfer photochemistry of high potential quinones, and the photophysical properties of organic dyes bound to water-soluble polymers. 9 figs.

  3. Transmission electron microscopic study of pyrochlore to defect-fluorite transition in rare-earth pyrohafnates

    SciTech Connect (OSTI)

    Karthik, Chinnathambi, E-mail: Karthikchinnathambi@boisestate.edu [Department of Materials Science and Engineering, Boise State University, 1910 University drive, Boise, ID 83725 (United States) [Department of Materials Science and Engineering, Boise State University, 1910 University drive, Boise, ID 83725 (United States); Center for Advanced Energy Studies, 995 University Blvd, Idaho Falls, ID 83415 (United States); Anderson, Thomas J. [Department of Materials Science and Engineering, Boise State University, 1910 University drive, Boise, ID 83725 (United States)] [Department of Materials Science and Engineering, Boise State University, 1910 University drive, Boise, ID 83725 (United States); Gout, Delphine [Oak Ridge National Lab, Neutron Scattering Science Division, Oak Ridge, TN (United States)] [Oak Ridge National Lab, Neutron Scattering Science Division, Oak Ridge, TN (United States); Ubic, Rick [Department of Materials Science and Engineering, Boise State University, 1910 University drive, Boise, ID 83725 (United States) [Department of Materials Science and Engineering, Boise State University, 1910 University drive, Boise, ID 83725 (United States); Center for Advanced Energy Studies, 995 University Blvd, Idaho Falls, ID 83415 (United States)

    2012-10-15T23:59:59.000Z

    A structural transition in rare earth pyrohafnates, Ln{sub 2}Hf{sub 2}O{sub 7} (Ln=Y, La, Pr, Nd, Tb, Dy, Yb and Lu), has been identified. Neutron diffraction showed that the structure transforms from well-ordered pyrochloric to fully fluoritic through the lanthanide series from La to Lu with a corresponding increase in the position parameter x of the 48f (Fd3{sup Macron }m) oxygen site from 0.330 to 0.375. As evidenced by the selected area electron diffraction, La{sub 2}Hf{sub 2}O{sub 7}, Pr{sub 2}Hf{sub 2}O{sub 7} and Nd{sub 2}Hf{sub 2}O{sub 7} exhibited a well-ordered pyrocholoric structure with the presence of intense superlattice spots, which became weak and diffuse (in Dy{sub 2}Hf{sub 2}O{sub 7} and Tb{sub 2}Hf{sub 2}O{sub 7}) before disappearing completely as the series progressed towards the Lu end. High resolution electron microscopic studies showed the breakdown of the pyrochlore ordering in the form of antiphase domains resulting in diffused smoke-like superlattice spots in the case of Dy{sub 2}Hf{sub 2}O{sub 7} and Tb{sub 2}Hf{sub 2}O{sub 7}. - Graphical abstract: Transmission electron microscopic studies showed the ordered pyrochlore to defect fluorite transition in rare-earth pyrohafnates to occur via the formation of anti-phase domains to start with. Highlights: Black-Right-Pointing-Pointer Pyrochlore to fluorite structural transition in rare earth pyrohafnates. Black-Right-Pointing-Pointer La{sub 2}Hf{sub 2}O{sub 7}, Pr{sub 2}Hf{sub 2}O{sub 7} and Nd{sub 2}Hf{sub 2}O{sub 7} showed well ordered pyrochlore structure. Black-Right-Pointing-Pointer Short range ordering in Dy{sub 2}Hf{sub 2}O{sub 7} and Tb{sub 2}Hf{sub 2}O{sub 7}. Black-Right-Pointing-Pointer Break down of pyrochlore ordering due to antiphase boundaries. Black-Right-Pointing-Pointer Rest of the series showed fluoritic structure.

  4. Reorganization Energy of Electron Transfer in Viscous Solvents above the Glass Transition Pradip K. Ghorai and Dmitry V. Matyushov*

    E-Print Network [OSTI]

    Matyushov, Dmitry

    Reorganization Energy of Electron Transfer in Viscous Solvents above the Glass Transition Pradip K-Einstein relation. The change in the reorganization energy at the transition temperature reflects the dynamical reorganization energy of electron transfer in supercooled water. We observe a sharp decrease

  5. Solvent Reorganization Energy and Free Energy Change for Donor/Acceptor Electron Transfer at Micelle Surfaces: Theory and Experiment

    E-Print Network [OSTI]

    Fayer, Michael D.

    Solvent Reorganization Energy and Free Energy Change for Donor/Acceptor Electron TransferVed: April 7, 1998 Theories are presented for calculating the solvent reorganization energy and the free region, and the surrounding water. The free energy change accompanying electron transfer can

  6. Theory of ultrafast photoinduced electron transfer from a bulk semiconductor to a quantum dot

    SciTech Connect (OSTI)

    Rasmussen, Andrew M., E-mail: andyras@gmail.com; Ramakrishna, S.; Weiss, Emily A.; Seideman, Tamar, E-mail: t-seideman@northwestern.edu [Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113 (United States)] [Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113 (United States)

    2014-04-14T23:59:59.000Z

    This paper describes analytical and numerical results from a model Hamiltonian method applied to electron transfer (ET) from a quasicontinuum (QC) of states to a set of discrete states, with and without a mediating bridge. Analysis of the factors that determine ET dynamics yields guidelines for achieving high-yield electron transfer in these systems, desired for instance for applications in heterogeneous catalysis. These include the choice of parameters of the laser pulse that excites the initial state into a continuum electronic wavepacket and the design of the coupling between the bridge molecule and the donor and acceptor. The vibrational mode on a bridging molecule between donor and acceptor has an influence on the yield of electron transfer via Franck-Condon factors, even in cases where excited vibrational states are only transiently populated. Laser-induced coherence of the initial state as well as energetic overlap is crucial in determining the ET yield from a QC to a discrete state, whereas the ET time is influenced by competing factors from the coupling strength and the coherence properties of the electronic wavepacket.

  7. Direct Visualization of Dendrite Nucleation and Growth Kinetics during Lithium Deposition with in situ Electrochemical Transmission Electron Microscopy

    SciTech Connect (OSTI)

    Sacci, Robert L [ORNL; Dudney, Nancy J [ORNL; More, Karren Leslie [ORNL; Browning, Nigel [Pacific Northwest National Laboratory (PNNL); Unocic, Raymond R [ORNL

    2014-01-01T23:59:59.000Z

    Formation of Li dendrites is a major safety concern existing in Li-ion secondary batteries. A quantitative electrochemistry method to investigate the dendrite nucleation and growth mechanisms at high spatial is presented. Cyclic voltammetry, in combination with in situ electrochemical transmission electron microscopy (in situ ec-TEM), was used to quantitatively characterize dendrite nucleation and growth mechanisms from a Au working electrode and within a 1.2M LiPF6 EC:DMC electrolyte.

  8. Electron transfer reactions in microporous solids. Progress report, September 1990--January 1993

    SciTech Connect (OSTI)

    Mallouk, T.E.

    1993-01-01T23:59:59.000Z

    Basic thrust the research program involves use of microporous solids (zeolites, clays, layered and tunnel structure oxide semiconductors) as organizing media for artificial photosynthetic systems. Purpose of the microporous solid is twofold. First, it induces spatial organization of photoactive and electroactive components (sensitizers, semiconductor particles, electron relays, and catalysts) at the solid-solution interface, enhancing the quantum efficiency of charge separation and separating physically the ultimate electron donor and acceptor in the electron transport chain. Second, since the microcrystalline solid admits only molecules of a certain charge and size, it is possible to achieve permanent charge separation by sieving chemical photoproducts (e.g., H{sub 2} and I{sub 3}{sup {minus}}, or H{sub 2} and O{sub 2)} from each other. Spectroscopic and electrochemical methods are used to study the kinetics of electron transfer reactions in these hybrid molecular/solid state assemblies.

  9. Manipulation of the distance of light-induced electron transfer within a semi-rigid donor(amine)/acceptor(terpyridine) assembly via

    E-Print Network [OSTI]

    structure calculations qualitatively reproduce the experimental observations. From the calculations interest in the kinetics and dynamics of electron transfer (ET) reac- tions, including reactions kinetics and dynamics studies: `how far is the electron transferred?' At first glance, this would appear

  10. Photoinduced Electron Transfer in Ordered Macromolecular Assemblies. Final report for May 1, 1988 - June 30, 2002

    SciTech Connect (OSTI)

    Jones, G.

    2005-02-11T23:59:59.000Z

    The final report describes studies over a 13 year period having to do with photoinduced electron transfer for active chromophores and redox agents, including assembly of the components in water soluble polymers or polypeptides. The findings include observation of long range charge separation and electron transport using laser phototransient spectroscopy. The systems targeted in these studies include peptide assemblies for which helical conformations and aggregation are documented. Oligomeric peptides modified with non-native redox active groups were also selected for investigation. Highly charged polymers or peptides were investigated as host agents that resemble proteins. The overall goal of these investigations focused on the design and characterization of systems capable of artificial photosynthesis.

  11. Vectorial electron transfer in spatially ordered arrays. Progress report, January 1991--January 1994

    SciTech Connect (OSTI)

    Fox, M.A.

    1994-01-01T23:59:59.000Z

    Objective was to find methods for rapid, controlled placement of light absorbers, relays, and multi-electron catalysts at defined sites with respect to a semiconductor or metal surface and thus to develop methods for preparing chemically modified photoactive surfaces as artificial photosynthetic units. Progress has been made in four areas: synthesis of new materials for directional electron transfer, preparation and characterization of anisotropic composites containing organic and inorganic components, elaboration of mechanisms of electrocatalysis, and development of new methods for surface modification of metals and semiconductors.

  12. Electron Transfer

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power AdministrationField Campaign:INEAWater UseC Supports - Energy3 Pierre Kennepohl1,2 and

  13. Nonlinear Ultrafast Spectroscopy of Electron and Energy Transfer in Molecule Complexes

    SciTech Connect (OSTI)

    Mukamel, Shaul

    2006-02-09T23:59:59.000Z

    The proposed research program will focus on the development of a unified dynamical theoretical framework for calculating the optical response of molecular assemblies and applying it towards studying the interplay of energy and charge transfer in artificial chromophore-aggregate complexes. Applications will be made to poly (p phenylene vinylene), (PPV) oligomers, several families of stilbenoid aggregates with stacking through a cyclophane group, coupled porphyrin arrays, and energy funneling in phenylacetylene dendrimers. The approach is based on formulating the problem using the density- matrix and developing Liouville-space techniques which provide physical insight and are particularly suitable for computing both coherent and incoherent transport. A physical picture based on collective electronic normal modes which represent the dynamics of the optically-driven reduced single electron density matrix will be established. Femtosecond signals and optical properties will be directly related to the motions of electron-hole pairs in real space, completely avoiding the calculation of many-electron excited-state wavefunctions, thus, considerably reducing computational effort. Vibrational and solvent effects will be incorporated. Guidelines for the synthesis of new donor/bridge/acceptor molecules with desired properties such as carrier transport, optical response time scales and fluorescence quantum yields will be developed. The analogy with Thz emission spectroscopy which probes charge carrier dynamic is in semiconductor superlattices will be explored. A systematic procedure for identifying the electronic coherence sizes which control the transport and optical properties will be developed. Localization of electronic transition density matrices of large molecules will be used to break the description of their optical response into coupled chromophores. The proposal is divided into four parts: (i) Collective-Oscillator Representation of Electronic Excitations in Molecular Assemblies; (ii) Nonlinear Optical Spectroscopy of Coupled Chromophores; (iii) Long-Range Electron Transfer and Transport in Solvents with Complex Spectral Densities; (iv) Probing Exciton-Migration by Coherent Femtosecond Spectroscopies.

  14. Vectorially photoinduced electron-transfer processes across water-in-oil interfaces of microemulsions

    SciTech Connect (OSTI)

    Willner, I.; Otvos, J.W.; Calvin, M.

    1980-07-01T23:59:59.000Z

    Artificial photosynthetic devices are potential fuel sources. The basic idea in the design of such devices is a photosensitized electron-transfer that yields chemical species capable of reducing and oxidizing water to hydrogen and oxygen. A fundamental difficulty in effecting this transfer is the thermodynamically favored back reactions of the intermediary redox species. An interfacial model composed of a water-in-oil microemulsion is suggested to provide the separation of these redox species, thereby preventing back-reactions. This model is designed to accomplish the photodecomposition of water in two separate water-in-oil microemulsions coupled by a redox reaction. Phase-transfer of one of the redox products from the water-in-oil interface to the continuous organic phase is the principle by which separation is achieved. The oxidation and reduction sites of the general model have been constructed. One system includes the photosensitized oxidation of a donor, EDTA, solubilized in the water pool, benzylnicotinamide acts as a primary acceptor that mediates by the phase transfer principle the reduction of a secondary acceptor, dimethylamino-azobenzene, solubilized in the continuous organic phase. In system two, involving the photosensitized reduction of methyl viologen, by tris(2,2'bipyridine)Ru(2+), thioophenol is used as the donor and its oxidation product is phase transferred to the continuous organic phase. The photoinduced processes accomplished in the two systems proceed along an uphill gradient of free energy. Two water soluble zinc-porphyrins can substitute for the Ru(2+) complex in the second system. As the two Zn-porphyrins are oppositely charged, the effect of electrostatic interactions on the quantum yields of viologen reduction could be evaluated. The results suggest that the surface charge of the wateroil interface strongly influences the efficiency of electron-transfer.

  15. Metal complex-based electron-transfer mediators in dye-sensitized solar cells

    DOE Patents [OSTI]

    Elliott, C. Michael (Fort Collins, CO); Sapp, Shawn A. (Broomfield, CO); Bignozzi, Carlo Alberto (Ferrara, IT); Contado, Cristiano (Legnago, IT); Caramori, Stefano (Viconovo, IT)

    2006-03-28T23:59:59.000Z

    This present invention provides a metal-ligand complex and methods for using and preparing the same. In particular, the metal-ligand complex of the present invention is of the formula: L.sub.a-M-X.sub.b where L, M, X, a, and b are those define herein. The metal-ligand complexes of the present invention are useful in a variety of applications including as electron-transfer mediators in dye-sensitized solar cells and related photoelectrochromic devices.

  16. 2. The TEM and its Optics 2.1 Introduction to the Transmission Electron

    E-Print Network [OSTI]

    -loss spectrometry (EELS), energy losses of the electrons are measured after the high-energy electrons have traversed, the high-energy electrons in TEM cause electronic excitations of the atoms in the specimen. Two important spectroscopic techniques make use of these excitations. · In energy-dispersive x-ray spectrometry (EDS), an x

  17. Transmission-mode imaging in the environmental scanning electron microscope (ESEM)

    E-Print Network [OSTI]

    Staniewicz, Lech Thomas Leif

    2012-02-07T23:59:59.000Z

    to convert mov- ing electrons into visible light or by photographic plates for image recording. This type of electron microscope has been retrospectively called a transmis- sion electron microscope, or TEM - this is in contrast to other methods of electron... -built devices, but they are not used in SEMs and as such will not be detailed here. 1.2.3 Electron Sources There are two main types of electron sources - thermionic and field-emission. They differ in the manner by which they produce free electrons - thermionic...

  18. In Search of the Inverted Region: Chromophore-Based Driving Force Dependence of Interfacial Electron Transfer Reactivity at the Nanocrystalline Titanium Dioxide

    E-Print Network [OSTI]

    Electron Transfer Reactivity at the Nanocrystalline Titanium Dioxide Semiconductor/Solution Interface Susan: June 20, 2000 Intentional variations of the driving force for back electron transfer from titanium electron transfer for several variants of the classic tris polypyridyl ruthenium/nanocrystalline titanium

  19. Electrostatic models of electron-driven proton transfer across a lipid membrane

    E-Print Network [OSTI]

    Anatoly Yu. Smirnov; Lev G. Mourokh; Franco Nori

    2010-11-29T23:59:59.000Z

    We present two models for electron-driven uphill proton transport across lipid membranes, with the electron energy converted to the proton gradient via the electrostatic interaction. In the first model, associated with the cytochrome c oxidase complex in the inner mitochondria membranes, the electrostatic coupling to the site occupied by an electron lowers the energy level of the proton-binding site, making the proton transfer possible. In the second model, roughly describing the redox loop in a nitrate respiration of E. coli bacteria, an electron displaces a proton from the negative side of the membrane to a shuttle, which subsequently diffuses across the membrane and unloads the proton to its positive side. We show that both models can be described by the same approach, which can be significantly simplified if the system is separated into several clusters, with strong Coulomb interaction inside each cluster and weak transfer couplings between them. We derive and solve the equations of motion for the electron and proton creation/annihilation operators, taking into account the appropriate Coulomb terms, tunnel couplings, and the interaction with the environment. For the second model, these equations of motion are solved jointly with a Langevin-type equation for the shuttle position. We obtain expressions for the electron and proton currents and determine their dependence on the electron and proton voltage build-ups, on-site charging energies, reorganization energies, temperature, and other system parameters. We show that the quantum yield in our models can be up to 100% and the power-conversion efficiency can reach 35%.

  20. Interfacial electron transfer dynamics of ru(II)-polypy6ridine sensitized TiO2

    SciTech Connect (OSTI)

    Jakubikova, Elena [Los Alamos National Laboratory; Martin, Richard L [Los Alamos National Laboratory; Batista, Enrique R [Los Alamos National Laboratory; Snoeberger, Robert C [YALE UNIV.; Batista, Victor S [YALE UNIV.

    2009-01-01T23:59:59.000Z

    Quantum dynamics simulations combined with density functional theory calculations are applied to study interfacial electron transfer (IET) from pyridine-4-phosphonic acid, [Ru(tpy)(tpy(PO{sub 3}H{sub 2}))]{sup 2+} and [Ru(tpy)(bpy)(H{sub 2}O)-Ru(tpy)(tpy(PO{sub 3}H{sub 2}))]{sup 4+} into the (101) surface of anatase TiO{sub 2}. IET rate from pyridine-4-phosphonic acid attached to the nanoparticle in bidentate mode ({tau} {approx} 100 fs) is an order of magnitude faster than the IET rate of the adsorbate attached in the monodentate mode ({tau} {approx} 1 ps). Upon excitation with visible light, [Ru(tpy)(tpy(PO{sub 3}H{sub 2}))]{sup 2+} attached to TiO{sub 2} in bidentate binding mode will undergo IET with the rate of {approx} 1-10 ps, which is competitive with the excited state decay into the ground state. The probability of electron injection from [Ru(tpy)(bpy)(H{sub 2}O)-Ru(tpy)(tpy(PO{sub 3}H{sub 2}))]{sup 4+} is rather low, as the excitation with visible light localizes the excited electron in the tpy-tpy bridge, which does not have favorable coupling with the TiO{sub 2} nanoparticle. The results are relevant to better understanding of the adsorbate features important for promoting efficient interfacial electron transfer into the semiconductor.

  1. Surface residues dynamically organize water bridges to enhance electron transfer between proteins

    E-Print Network [OSTI]

    de la Lande, Aurélien; ?ezá?, Jan; Sanders, Barry C; Salahub, Dennis R; 10.1073/pnas.0914457107

    2010-01-01T23:59:59.000Z

    Cellular energy production depends on electron transfer (ET) between proteins. In this theoretical study, we investigate the impact of structural and conformational variations on the electronic coupling between the redox proteins methylamine dehydrogenase and amicyanin from Paracoccus denitrificans. We used molecular dynamics simulations to generate configurations over a duration of 40ns (sampled at 100fs intervals) in conjunction with an ET pathway analysis to estimate the ET coupling strength of each configuration. In the wild type complex, we find that the most frequently occurring molecular configurations afford superior electronic coupling due to the consistent presence of a water molecule hydrogen-bonded between the donor and acceptor sites. We attribute the persistence of this water bridge to a "molecular breakwater" composed of several hydrophobic residues surrounding the acceptor site. The breakwater supports the function of nearby solvent-organizing residues by limiting the exchange of water molecul...

  2. A parametric study of shock jump chemistry, electron temperature, and radiative heat transfer models in hypersonic flows

    E-Print Network [OSTI]

    Greendyke, Robert Brian

    1988-01-01T23:59:59.000Z

    A PARAMETRIC STUDY OF SHOCK JUMP CHEMISTRY, ELECTRON TEMPERATURE, AND RADIATIVE HEAT TRANSFER MODELS IN HYPERSONIC FLOWS A Thesis by ROBERT BRIAN GREENDYKE Submitted to the Graduate College of Texas A&M University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE August 1988 Major Subject: Aerospace Engineering A PARAMETRIC STUDY OF SHOCK JUMP CHEMISTRY, ELECTRON TEMPERATURE, AND RADIATIVE HEAT TRANSFER MODELS IN HYPERSONIC FLOWS A Thesis by ROBERT BRIAN...

  3. Largely defocused probe scanning transmission electron microscopy for imaging local modulation of strain field in a hetero interface

    SciTech Connect (OSTI)

    Kim, Suhyun, E-mail: u98kim@surface.phys.titech.ac.jp; Jung, Younheum; Kim, Joong Jung; Lee, Sunyoung; Lee, Haebum [Memory Analysis Science and Engineering Group, Samsung Electronics, San #16 Hwasung-City, Gyeonggi-Do 445-701 (Korea, Republic of); Oshima, Yoshifumi [School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292 (Japan)

    2014-10-13T23:59:59.000Z

    We present an innovative method for characterizing the strain field in three dimensions in a hetero interface. Largely defocused probe scanning transmission electron microscopy (LDP-STEM) was employed for imaging the inhomogeneous strain field in a germanium (Ge) layer deposited on a silicon (Si) substrate. In the LDP-STEM image, Ge-atomic columns that are relaxed or strained to the Si substrate in the Si/Ge hetero interface were observed to be distinguishable, allowing for the qualitative characterization of the coherency of the crystal growth. Our results revealed that the strain field is locally modulated along the in-plane direction in the Si/Ge hetero interface.

  4. In situ transmission electron microscopy investigation of the interfacial reaction between Ni and Al during rapid heating in a nanocalorimeter

    SciTech Connect (OSTI)

    Grapes, Michael D., E-mail: mgrapes1@jhu.edu, E-mail: david.lavan@nist.gov, E-mail: weihs@jhu.edu [Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Material Measurement Laboratory, Materials Measurement Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); LaGrange, Thomas; Reed, Bryan W.; Campbell, Geoffrey H. [Lawrence Livermore National Laboratory, Materials Science and Technology Division, Livermore, California 94550 (United States); Woll, Karsten [Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Institute of Applied Materials, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen (Germany); LaVan, David A., E-mail: mgrapes1@jhu.edu, E-mail: david.lavan@nist.gov, E-mail: weihs@jhu.edu [Material Measurement Laboratory, Materials Measurement Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Weihs, Timothy P., E-mail: mgrapes1@jhu.edu, E-mail: david.lavan@nist.gov, E-mail: weihs@jhu.edu [Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States)

    2014-11-01T23:59:59.000Z

    The Al/Ni formation reaction is highly exothermic and of both scientific and technological significance. In this report, we study the evolution of intermetallic phases in this reaction at a heating rate of 830 K/s. 100-nm-thick Al/Ni bilayers were deposited onto nanocalorimeter sensors that enable the measurement of temperature and heat flow during rapid heating. Time-resolved transmission electron diffraction patterns captured simultaneously with thermal measurements allow us to identify the intermetallic phases present and reconstruct the phase transformation sequence as a function of time and temperature. The results show a mostly unaltered phase transformation sequence compared to lower heating rates.

  5. Direct imaging of light elements by annular dark-field aberration-corrected scanning transmission electron microscopy

    SciTech Connect (OSTI)

    Lotnyk, Andriy, E-mail: andriy.lotnyk@iom-leipzig.de; Poppitz, David; Gerlach, Jürgen W.; Rauschenbach, Bernd [Leibniz Institute of Surface Modification, Permoserstr. 15, D-04318 Leipzig (Germany)

    2014-02-17T23:59:59.000Z

    In this report, we show that an annular dark-field detector in an aberration-corrected scanning transmission electron microscope allows the direct observation of light element columns in crystalline lattices. At specific imaging conditions, an enhancement of the intensities of light element columns in the presence of heavy element columns is observed. Experimental results are presented for imaging the nitrogen and carbon atomic columns at the GaN-SiC interface and within the GaN and SiC compounds. The crystal polarity of GaN at the interface is identified. The obtained findings are discussed and are well supported by image simulations.

  6. In situ Regeneration of NADH via Lipoamide Dehydrogenase-catalyzed Electron Transfer Reaction Evidenced by Spectroelectrochemistry

    SciTech Connect (OSTI)

    Tam, Tsz Kin; Chen, Baowei; Lei, Chenghong; Liu, Jun

    2012-08-01T23:59:59.000Z

    NAD/NADH is a coenzyme found in all living cells, carrying electrons from one reaction to another. We report on characterizations of in situ regeneration of NADH via lipoamide dehydrogenase (LD)-catalyzed electron transfer reaction to regenerate NADH using UV-vis spectroelectrochemistry. The Michaelis-Menten constant (Km) and maximum velocity (Vmax) of NADH regeneration were measured as 0.80 {+-} 0.15 mM and 1.91 {+-} 0.09 {micro}M s-1 in a 1-mm thin-layer spectroelectrochemical cell using gold gauze as the working electrode at the applied potential -0.75 V (vs. Ag/AgCl). The electrocatalytic reduction of the NAD system was further coupled with the enzymatic conversion of pyruvate to lactate by lactate dehydrogenase to examine the coenzymatic activity of the regenerated NADH. Although the reproducible electrocatalytic reduction of NAD into NADH is known to be difficult compared to the electrocatalytic oxidation of NADH, our spectroelectrochemical results indicate that the in situ regeneration of NADH via LD-catalyzed electron transfer reaction is fast and sustainable and can be potentially applied to many NAD/NADH-dependent enzyme systems.

  7. Can direct extracellular electron transfer occur in the absence of outer membrane cytochromes in Desulfovibrio vulgaris?

    SciTech Connect (OSTI)

    Elias, Dwayne A [ORNL] [ORNL; Zane, Mr. Grant M. [University of Missouri, Columbia] [University of Missouri, Columbia; Auer, Dr. Manfred [Lawrence Berkeley National Laboratory (LBNL)] [Lawrence Berkeley National Laboratory (LBNL); Fields, Dr. Matthew Wayne [Montana State University] [Montana State University; Wall, Judy D. [University of Missouri] [University of Missouri; Gorby, Dr. Yuri A. [J. Craig Venter Institute] [J. Craig Venter Institute

    2010-01-01T23:59:59.000Z

    Extracellular electron transfer has been investigated over several decades via forms of soluble electron transfer proteins that are exported for extracellular reoxidation. More recently, several organisms have been shown to reduce extracellular metals via the direct transfer of electron through appendages; also known as nanowires. They have been reported most predominantly in Shewanella and Geobacter. While the relevancy and composition of these structures in each genus has been debated, both possess outer membrane cytochrome complexes that could theoretically come into direct contact with solid phase oxidized metals. Members of the genus Desulfovibrio apparently have no such cytochromes although similar appendages are present, are electrically conductive, and are different from flagella. Upon U(VI)-reduction, the structures in Desulfovibrio become coated with U(IV). Deletion of flagellar genes did not alter soluble or amorphous Fe(III) or U(VI) reduction, or appendage appearance. Removal of the chromosomal pilA gene hampered amorphous Fe(III)-reduction by ca. 25%, but cells lacking the native plasmid, pDV1, reduced soluble Fe(III) and U(VI) at ca. 50% of the wild type rate while amorphous Fe(III)-reduction slowed to ca. 20% of the wild type rate. Appendages were present in all deletions as well as pDV1, except pilA. Gene complementation restored all activities and morphologies to wild type levels. This suggests that pilA encodes the structural component, whereas genes within pDV1 may provide the reactive members. How such appendages function without outer membrane cytochromes is under investigation.

  8. Electronic and vibronic properties of a discotic liquid-crystal and its charge transfer complex

    SciTech Connect (OSTI)

    Haverkate, Lucas A.; Mulder, Fokko M. [Reactor Institute Delft, Faculty of Applied Sciences, Delft University of Technology, Mekelweg 15, 2629JB Delft (Netherlands)] [Reactor Institute Delft, Faculty of Applied Sciences, Delft University of Technology, Mekelweg 15, 2629JB Delft (Netherlands); Zbiri, Mohamed, E-mail: zbiri@ill.fr; Johnson, Mark R. [Institut Laue Langevin, 38042 Grenoble Cedex 9 (France)] [Institut Laue Langevin, 38042 Grenoble Cedex 9 (France); Carter, Elizabeth [Vibrational Spectroscopy Facility, School of Chemistry, The University of Sydney, NSW 2008 (Australia)] [Vibrational Spectroscopy Facility, School of Chemistry, The University of Sydney, NSW 2008 (Australia); Kotlewski, Arek; Picken, S. [ChemE-NSM, Faculty of Chemistry, Delft University of Technology, 2628BL/136 Delft (Netherlands)] [ChemE-NSM, Faculty of Chemistry, Delft University of Technology, 2628BL/136 Delft (Netherlands); Kearley, Gordon J. [Bragg Institute, Australian Nuclear Science and Technology Organisation, Menai, NSW 2234 (Australia)] [Bragg Institute, Australian Nuclear Science and Technology Organisation, Menai, NSW 2234 (Australia)

    2014-01-07T23:59:59.000Z

    Discotic liquid crystalline (DLC) charge transfer (CT) complexes combine visible light absorption and rapid charge transfer characteristics, being favorable properties for photovoltaic (PV) applications. We present a detailed study of the electronic and vibrational properties of the prototypic 1:1 mixture of discotic 2,3,6,7,10,11-hexakishexyloxytriphenylene (HAT6) and 2,4,7-trinitro-9-fluorenone (TNF). It is shown that intermolecular charge transfer occurs in the ground state of the complex: a charge delocalization of about 10{sup ?2} electron from the HAT6 core to TNF is deduced from both Raman and our previous NMR measurements [L. A. Haverkate, M. Zbiri, M. R. Johnson, B. Deme, H. J. M. de Groot, F. Lefeber, A. Kotlewski, S. J. Picken, F. M. Mulder, and G. J. Kearley, J. Phys. Chem. B 116, 13098 (2012)], implying the presence of permanent dipoles at the donor-acceptor interface. A combined analysis of density functional theory calculations, resonant Raman and UV-VIS absorption measurements indicate that fast relaxation occurs in the UV region due to intramolecular vibronic coupling of HAT6 quinoidal modes with lower lying electronic states. Relatively slower relaxation in the visible region the excited CT-band of the complex is also indicated, which likely involves motions of the TNF nitro groups. The fast quinoidal relaxation process in the hot UV band of HAT6 relates to pseudo-Jahn-Teller interactions in a single benzene unit, suggesting that the underlying vibronic coupling mechanism can be generic for polyaromatic hydrocarbons. Both the presence of ground state CT dipoles and relatively slow relaxation processes in the excited CT band can be relevant concerning the design of DLC based organic PV systems.

  9. Photochemical charge separation in zeolites: Electron transfer dynamics, nanocrystals and zeolitic membranes. Final technical report

    SciTech Connect (OSTI)

    Dutta, Prabir K.

    2001-09-30T23:59:59.000Z

    Aluminosilicate zeolites provide an excellent host for photochemical charge separation. Because of the constraints provided by the zeolite, the back electron transfer from the reduced acceptor to the oxidized sensitizer is slowed down. This provides the opportunity to separate the charge and use it in a subsequent reaction for water oxidation and reduction. Zeolite-based ruthenium oxide catalysts have been found to be efficient for the water splitting process. This project has demonstrated the usefulness of zeolite hosts for photolytic splitting of water.

  10. Electron transfer in a two-level system within a Cole-Davidson vitreous bath

    SciTech Connect (OSTI)

    Zarea, Mehdi, E-mail: m-zarea@northwestern.edu; Ratner, Mark A.; Wasielewski, Michael R. [Argonne-Northwestern Solar Energy Research (ANSER) Center, Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113 (United States)] [Argonne-Northwestern Solar Energy Research (ANSER) Center, Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113 (United States)

    2014-01-14T23:59:59.000Z

    We study electron transfer (ET) in a two level quantum system coupled to a glassy viscous bath. The bath is modeled by the Cole-Davidson (CD) spectral density. The ET in this model is compared to the ET in a normal Drude-Debye (DD) model. It is shown that at low temperatures and when the coupling to the bath is weak, the viscous bath preserves the quantum coherence for a longer time. However in the strong coupling regime, the tunneling rate is higher in the CD. In the classical high temperature limit the difference between the CD and DD models is negligible.

  11. Transmission electron microscopy assisted in-situ joule heat dissipation study of individual InAs nanowires

    SciTech Connect (OSTI)

    Xu, T. T.; Wei, X. L., E-mail: weixl@pku.edu.cn, E-mail: qingchen@pku.edu.cn; Shu, J. P.; Chen, Q., E-mail: weixl@pku.edu.cn, E-mail: qingchen@pku.edu.cn [Key Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics, Peking University, Beijing 100871 (China)

    2013-11-04T23:59:59.000Z

    Managing heat transport at nanoscale is an important and challenging task for nanodevice applications and nanostructure engineering. Herein, through in-situ engineering nanowire (NW)-electrode contacts with electron beam induced carbon deposition in a transmission electron microscope, Joule heat dissipation along individual suspended Indium Arsenide NWs is well managed to obtain pre-designed temperature profiles along NWs. The temperature profiles are experimentally determined by the breakdown site of NWs under Joule heating and breakdown temperature measurement. A model with NW-electrode contacts being well considered is proposed to describe heat transport along a NW. By fitting temperature profiles with the model, thermal conductance at NW-electrode contacts is obtained. It is found that, the temperature profile along a specific NW is mainly governed by the relative thermal conductance at the two NW-electrode contacts, which is engineered in experiments.

  12. Fragment transition density method to calculate electronic coupling for excitation energy transfer

    SciTech Connect (OSTI)

    Voityuk, Alexander A., E-mail: alexander.voityuk@icrea.cat [Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain and Institut de Química Computacional i Catàlisi (IQCC), Universitat de Girona 17071 Girona (Spain)

    2014-06-28T23:59:59.000Z

    A general approach, the Fragment Transition Density (FTD) scheme, is introduced to estimate electronic coupling for excitation energy transfer in a molecular system. Within this method, the excitation energies and transition densities of the system are used to derive the coupling matrix element. The scheme allows one to treat systems where exciton donor and acceptor are close together and their exchange interaction and orbital overlap are significant. The FTD method can be applied in combination with any quantum mechanical approach to treat excited states of general nature including single-, double-, and higher excitations. Using FTD approach, we derive excitonic couplings for several systems computed with the CIS, TD DFT and MS-CASPT2 methods. In particular, it is shown that the estimated coupling values in DNA ?-stacks are strongly affected by the short-range electronic interaction of adjacent nucleobases.

  13. Coupled electron-nuclear dynamics: Charge migration and charge transfer initiated near a conical intersection

    SciTech Connect (OSTI)

    Mendive-Tapia, David; Vacher, Morgane; Bearpark, Michael J.; Robb, Michael A. [Department of Chemistry, Imperial College London, London SW7 2AZ (United Kingdom)] [Department of Chemistry, Imperial College London, London SW7 2AZ (United Kingdom)

    2013-07-28T23:59:59.000Z

    Coupled electron-nuclear dynamics, implemented using the Ehrenfest method, has been used to study charge migration with fixed nuclei, together with charge transfer when nuclei are allowed to move. Simulations were initiated at reference geometries of neutral benzene and 2-phenylethylamine (PEA), and at geometries close to potential energy surface crossings in the cations. Cationic eigenstates, and the so-called sudden approximation, involving removal of an electron from a correlated ground-state wavefunction for the neutral species, were used as initial conditions. Charge migration without coupled nuclear motion could be observed if the Ehrenfest simulation, using the sudden approximation, was started near a conical intersection where the states were both strongly coupled and quasi-degenerate. Further, the main features associated with charge migration were still recognizable when the nuclear motion was allowed to couple. In the benzene radical cation, starting from the reference neutral geometry with the sudden approximation, one could observe sub-femtosecond charge migration with a small amplitude, which results from weak interaction with higher electronic states. However, we were able to engineer large amplitude charge migration, with a period between 10 and 100 fs, corresponding to oscillation of the electronic structure between the quinoid and anti-quinoid cationic electronic configurations, by distorting the geometry along the derivative coupling vector from the D{sub 6h} Jahn-Teller crossing to lower symmetry where the states are not degenerate. When the nuclear motion becomes coupled, the period changes only slightly. In PEA, in an Ehrenfest trajectory starting from the D{sub 2} eigenstate and reference geometry, a partial charge transfer occurs after about 12 fs near the first crossing between D{sub 1}, D{sub 2} (N{sup +}-Phenyl, N-Phenyl{sup +}). If the Ehrenfest propagation is started near this point, using the sudden approximation without coupled nuclear motion, one observes an oscillation of the spin density – charge migration – between the N atom and the phenyl ring with a period of 4 fs. When the nuclear motion becomes coupled, this oscillation persists in a damped form, followed by an effective charge transfer after 30 fs.

  14. Xenotransplantation of mitochondrial electron transfer enzyme, Ndi1, treats myocardial reperfusion injury

    E-Print Network [OSTI]

    Perry, Cynthia Nicole

    2011-01-01T23:59:59.000Z

    Transfer Enzyme, Ndi1, Treats Myocardial Reperfusion InjuryTransfer Enzyme, Ndi1, Treats Myocardial Reperfusion Injury

  15. Monday, 14 July, 2008 Radiation belt electron precipitation by manmade VLF transmissions1

    E-Print Network [OSTI]

    Otago, University of

    -like enhancements produced by the transmitter NPM, despite its low-latitude location and30 relatively high output-generated wisps and the lack of NPM-generated wisps.33 1. Introduction34 The behavior of high energy electrons

  16. Atomic-scale and three-dimensional transmission electron microscopy of nanoparticle morphology

    E-Print Network [OSTI]

    Leary, Rowan Kendall

    2015-02-03T23:59:59.000Z

    nanoparticles with reactive concave surfaces. A compressed sensing-electron tomography (CS-ET) approach. Nano Letters, 11(11): 4666-4673, 2011. Peer reviewed conference proceedings R. Leary, Z. Saghi, P.A. Midgley, and D.J. Holland. Compressed Sensing Electron... algorithms, precision in component fabrication and stability of electrical components that AC optics yielded performance improvements in practice. First generation AC optics have addressed the major limiting aberration, third-order spherical aberration. In a...

  17. Impact of environmentally induced fluctuations on quantum mechanically mixed electronic and vibrational pigment states in photosynthetic energy transfer and 2D electronic spectra

    E-Print Network [OSTI]

    Fujihashi, Yuta; Ishizaki, Akihito

    2015-01-01T23:59:59.000Z

    Recently, nuclear vibrational contribution signatures in 2D electronic spectroscopy have attracted considerable interest, in particular as regards interpretation of the oscillatory transients observed in light-harvesting complexes. These transients have dephasing times that persist for much longer than theoretically predicted electronic coherence lifetime. As a plausible explanation for this long-lived spectral beating in 2D electronic spectra, quantum-mechanically mixed electronic and vibrational states (vibronic excitons) were proposed by Christensson et al. [J. Phys. Chem. B 116, 7449 (2012)] and have since been explored. In this work, we address a dimer which produces little beating of electronic origin in the absence of vibronic contributions, and examine the impact of protein-induced fluctuations upon electronic-vibrational quantum mixtures by calculating the electronic energy transfer dynamics and 2D electronic spectra in a numerically accurate manner. It is found that, at cryogenic temperatures, the e...

  18. Structural and orientation effects on electronic energy transfer between silicon quantum dots with dopants and with silver adsorbates

    SciTech Connect (OSTI)

    Vinson, N.; Freitag, H.; Micha, D. A., E-mail: micha@qtp.ufl.edu [Quantum Theory Project, Departments of Chemistry and Physics, University of Florida, Gainesville, Florida 32611 (United States)

    2014-06-28T23:59:59.000Z

    Starting from the atomic structure of silicon quantum dots (QDs), and utilizing ab initio electronic structure calculations within the Förster resonance energy transfer (FRET) treatment, a model has been developed to characterize electronic excitation energy transfer between QDs. Electronic energy transfer rates, K{sub EET}, between selected identical pairs of crystalline silicon quantum dots systems, either bare, doped with Al or P, or adsorbed with Ag and Ag{sub 3}, have been calculated and analyzed to extend previous work on light absorption by QDs. The effects of their size and relative orientation on energy transfer rates for each system have also been considered. Using time-dependent density functional theory and the hybrid functional HSE06, the FRET treatment was employed to model electronic energy transfer rates within the dipole-dipole interaction approximation. Calculations with adsorbed Ag show that: (a) addition of Ag increases rates up to 100 times, (b) addition of Ag{sub 3} increases rates up to 1000 times, (c) collinear alignment of permanent dipoles increases transfer rates by an order of magnitude compared to parallel orientation, and (d) smaller QD-size increases transfer due to greater electronic orbitals overlap. Calculations with dopants show that: (a) p-type and n-type dopants enhance energy transfer up to two orders of magnitude, (b) surface-doping with P and center-doping with Al show the greatest rates, and (c) K{sub EET} is largest for collinear permanent dipoles when the dopant is on the outer surface and for parallel permanent dipoles when the dopant is inside the QD.

  19. Dynamic Processes in Biology, Chemistry, and Materials Science: Opportunities for UltraFast Transmission Electron Microscopy - Workshop Summary Report

    SciTech Connect (OSTI)

    Kabius, Bernd C.; Browning, Nigel D.; Thevuthasan, Suntharampillai; Diehl, Barbara L.; Stach, Eric A.

    2012-07-25T23:59:59.000Z

    This report summarizes a 2011 workshop that addressed the potential role of rapid, time-resolved electron microscopy measurements in accelerating the solution of important scientific and technical problems. A series of U.S. Department of Energy (DOE) and National Academy of Science workshops have highlighted the critical role advanced research tools play in addressing scientific challenges relevant to biology, sustainable energy, and technologies that will fuel economic development without degrading our environment. Among the specific capability needs for advancing science and technology are tools that extract more detailed information in realistic environments (in situ or operando) at extreme conditions (pressure and temperature) and as a function of time (dynamic and time-dependent). One of the DOE workshops, Future Science Needs and Opportunities for Electron Scattering: Next Generation Instrumentation and Beyond, specifically addressed the importance of electron-based characterization methods for a wide range of energy-relevant Grand Scientific Challenges. Boosted by the electron optical advancement in the last decade, a diversity of in situ capabilities already is available in many laboratories. The obvious remaining major capability gap in electron microscopy is in the ability to make these direct in situ observations over a broad spectrum of fast (µs) to ultrafast (picosecond [ps] and faster) temporal regimes. In an effort to address current capability gaps, EMSL, the Environmental Molecular Sciences Laboratory, organized an Ultrafast Electron Microscopy Workshop, held June 14-15, 2011, with the primary goal to identify the scientific needs that could be met by creating a facility capable of a strongly improved time resolution with integrated in situ capabilities. The workshop brought together more than 40 leading scientists involved in applying and/or advancing electron microscopy to address important scientific problems of relevance to DOE’s research mission. This workshop built on previous workshops and included three breakout sessions identifying scientific challenges in biology, biogeochemistry, catalysis, and materials science frontier areas of fundamental science that underpin energy and environmental science that would significantly benefit from ultrafast transmission electron microscopy (UTEM). In addition, the current status of time-resolved electron microscopy was examined, and the technologies that will enable future advances in spatio-temporal resolution were identified in a fourth breakout session.

  20. Tailoring of electron flow current in magnetically insulated transmission lines J. P. Martin,2,3

    E-Print Network [OSTI]

    Security Administration's Kansas City Plant, Kansas City, Missouri 64141, USA (Received 16 September 2008) flowing electrons generally do not deliver energy to (or even reach) most loads, and thus constitute a balance of the two. While magnetically insulated systems are generally forgiving, there are times when

  1. Photoinduced electron transfer processes in homogeneous and microheterogeneous solutions. Progress report, April 16, 1992--December 1, 1992

    SciTech Connect (OSTI)

    Whitten, D.G.

    1992-12-01T23:59:59.000Z

    The studies have focused on rapid, efficient bond-fragmentation reactions initiated through photoinduced electron transfer. Electron transfer induced fragmentation of a number of donors have been examined, especially 1,2 diamines and related compounds. Two of the amines fragment with rate constants of 3 {times} 10{sup 8} to 2 {times} 10{sup 9} M{sup {minus}1}sec{sup {minus}1}. A series of amino-substituted pinacols and related compounds have also been examined; they undergo similar but slower fragmentation processes when converted to their cation radicals by photoinduced electron transfer. The studies with linked and polymeric electron donor- electron acceptor coupled molecules have also progressed. Several polymers containing diamine repeat units and anthraquinone or nitroaromatic acceptors have also been prepared that can be photoactivated by visible irradiation; they fragment efficiently in solution and photodegrade even in the solid state. The studies of singlet oxygen initiated fragmentation reactions of diamines, amino alcohols, and aminoketones have nearly been completed. Attention have been turned to fragmentable electron acceptors such as p- cyanobenzyl bromide; irradiation of electron donors such as methyl- or methoxy-naphthalenes can initiate efficient fragmentation of the electron deficient bromide.

  2. Combining nanocalorimetry and dynamic transmission electron microscopy for in situ characterization of materials processes under rapid heating and cooling

    SciTech Connect (OSTI)

    Grapes, Michael D., E-mail: mgrapes1@jhu.edu [Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); LaGrange, Thomas; Reed, Bryan W.; Campbell, Geoffrey H. [Condensed Matter and Materials Division, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Friedman, Lawrence H.; LaVan, David A., E-mail: david.lavan@nist.gov [Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Weihs, Timothy P., E-mail: weihs@jhu.edu [Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States)

    2014-08-15T23:59:59.000Z

    Nanocalorimetry is a chip-based thermal analysis technique capable of analyzing endothermic and exothermic reactions at very high heating and cooling rates. Here, we couple a nanocalorimeter with an extremely fast in situ microstructural characterization tool to identify the physical origin of rapid enthalpic signals. More specifically, we describe the development of a system to enable in situ nanocalorimetry experiments in the dynamic transmission electron microscope (DTEM), a time-resolved TEM capable of generating images and electron diffraction patterns with exposure times of 30 ns–500 ns. The full experimental system consists of a modified nanocalorimeter sensor, a custom-built in situ nanocalorimetry holder, a data acquisition system, and the DTEM itself, and is capable of thermodynamic and microstructural characterization of reactions over a range of heating rates (10{sup 2} K/s–10{sup 5} K/s) accessible by conventional (DC) nanocalorimetry. To establish its ability to capture synchronized calorimetric and microstructural data during rapid transformations, this work describes measurements on the melting of an aluminum thin film. We were able to identify the phase transformation in both the nanocalorimetry traces and in electron diffraction patterns taken by the DTEM. Potential applications for the newly developed system are described and future system improvements are discussed.

  3. Hot-electron-driven charge transfer processes on O2 Pt,,111... surface probed by ultrafast extreme-ultraviolet pulses

    E-Print Network [OSTI]

    Bauer, Michael

    it with an ultrafast laser pulse, charge transfer induced changes in the platinum-oxygen bond were observedHot-electron-driven charge transfer processes on O2 Ã?Pt,,111... surface probed by ultrafast extreme-ultraviolet pulses C. Lei,1, * M. Bauer,2 K. Read,1 R. Tobey,1 Y. Liu,3 T. Popmintchev,1 M. M. Murnane,1 and H. C

  4. Ultrafast single-electron transfer in coupled quantum dots driven by a few-cycle chirped pulse

    SciTech Connect (OSTI)

    Yang, Wen-Xing, E-mail: wenxingyang2@126.com [Department of Physics, Southeast University, Nanjing 210096 (China); Institute of Photonics Technologies, National Tsing-Hua University, Hsinchu 300, Taiwan (China); Chen, Ai-Xi [Department of Applied Physics, School of Basic Science, East China Jiaotong University, Nanchang 330013 (China); Bai, Yanfeng [Department of Physics, Southeast University, Nanjing 210096 (China); Lee, Ray-Kuang [Institute of Photonics Technologies, National Tsing-Hua University, Hsinchu 300, Taiwan (China)

    2014-04-14T23:59:59.000Z

    We theoretically study the ultrafast transfer of a single electron between the ground states of a coupled double quantum dot (QD) structure driven by a nonlinear chirped few-cycle laser pulse. A time-dependent Schrödinger equation without the rotating wave approximation is solved numerically. We demonstrate numerically the possibility to have a complete transfer of a single electron by choosing appropriate values of chirped rate parameters and the intensity of the pulse. Even in the presence of the spontaneous emission and dephasing processes of the QD system, high-efficiency coherent transfer of a single electron can be obtained in a wide range of the pulse parameters. Our results illustrate the potential to utilize few-cycle pulses for the excitation in coupled quantum dot systems through the nonlinear chirp parameter control, as well as a guidance in the design of experimental implementation.

  5. Resolution of electron and proton transfer events in the electrochromism associated with quinone reduction in bacterial reaction centers.

    SciTech Connect (OSTI)

    Tiede, D. M.; Utschig, L.; Gallo, D. M.; Hanson, D. K.; Augustana Coll.

    1998-01-01T23:59:59.000Z

    We have measured the electrochromic response of the bacteriopheophytin, BPh, and bacteriochlorophyll, BChl, cofactors during the Q{sub A} {sup -}Q{sub B} {yields} Q{sub A}Q{sub B}{sup -} electron transfer in chromatophores of Rhodobacter (Rb.) capsulatus and Rb. sphaeroides. The electrochromic response rises faster in chromatophores and is more clearly biexponential than it is in isolated reaction centers. The chromatophore spectra can be interpreted in terms of a clear kinetic separation between fast electron transfer and slower non-electron transfer events such as proton transfer or protein relaxation. The electrochromic response to electron transfer exhibits rise times of about 4 {micro}s (70%) and 40 {micro}s (30%) in Rb. capsulatus and 4 {micro}s (60%) and 80 {micro}s (40%) in Rb. sphaeroides. The BPh absorption band is shifted to nearly equivalent positions in the Q{sub A}{sup -} and nascent Q{sub B}{sup -} states, indicating that the electrochromic perturbation of BPh absorption from the newly formed Q{sub B}{sup -} state is comparable to that of Q{sub A}{sup -} . Subsequently, partial attenuation of the Q{sub B}{sup -} electrochromism occurs with a time constant on the order of 200 {micro}s. This can be attributed to partial charge compensation by H{sup +} (or other counter ion) movement into the Q{sub B} pocket. Electron transfer events were found to be slower in detergent isolated RCs than in chromatophores, more nearly monoexponential, and overlap H{sup +} transfer, suggesting that a change in rate-limiting step has occurred upon detergent solubilization.

  6. Optimal experimental design for the detection of light atoms from high-resolution scanning transmission electron microscopy images

    SciTech Connect (OSTI)

    Gonnissen, J.; De Backer, A.; Martinez, G. T.; Van Aert, S., E-mail: Sandra.VanAert@uantwerpen.be [Electron Microscopy for Materials Science, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp (Belgium); Dekker, A. J. den [iMinds-Vision Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk (Belgium); Delft Center for Systems and Control, Delft University of Technology, Mekelweg 2, 2628 CD Delft (Netherlands); Rosenauer, A. [Institute of Solid State Physics, University of Bremen, Otto-Hahn-Allee NW1, 28359 Bremen (Germany); Sijbers, J. [iMinds-Vision Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk (Belgium)

    2014-08-11T23:59:59.000Z

    We report an innovative method to explore the optimal experimental settings to detect light atoms from scanning transmission electron microscopy (STEM) images. Since light elements play a key role in many technologically important materials, such as lithium-battery devices or hydrogen storage applications, much effort has been made to optimize the STEM technique in order to detect light elements. Therefore, classical performance criteria, such as contrast or signal-to-noise ratio, are often discussed hereby aiming at improvements of the direct visual interpretability. However, when images are interpreted quantitatively, one needs an alternative criterion, which we derive based on statistical detection theory. Using realistic simulations of technologically important materials, we demonstrate the benefits of the proposed method and compare the results with existing approaches.

  7. Hot-stage transmission electron microscopy study of (Na, K)NbO{sub 3} based lead-free piezoceramics

    SciTech Connect (OSTI)

    Lu, Shengbo, E-mail: shengbo.lu@yahoo.com [Department of Physics and Materials Science, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon (Hong Kong); Department of Applied Physics and Materials Research Centre, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); Xu, Zhengkui [Department of Physics and Materials Science, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon (Hong Kong); Kwok, K. W.; Chan, Helen L. W. [Department of Applied Physics and Materials Research Centre, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong)

    2014-07-28T23:59:59.000Z

    Hierarchical nanodomains assembled into micron-sized stripe domains, which is believed to be associated with outstanding piezoelectric properties, were observed at room temperature in a typical lead free piezoceramics, (Na{sub 0.52}K{sub 0.48?x})(Nb{sub 0.95?x}Ta{sub 0.05})-xLiSbO{sub 3}, with finely tuned polymorphic phase boundaries (x?=?0.0465) by transmission electron microscopy. The evolution of domain morphology and crystal structure under heating and cooling cycles in the ceramic was investigated by in-situ hot stage study. It is found that the nanodomains are irreversibly transformed into micron-sized rectangular domains during heating and cooling cycles, which lead to the thermal instability of piezoelectric properties of the materials.

  8. Controlled polarity of sputter-deposited aluminum nitride on metals observed by aberration corrected scanning transmission electron microscopy

    SciTech Connect (OSTI)

    Harumoto, T. [Department of Metallurgy and Ceramics Science, Tokyo Institute of Technology, 2-12-1-S8-6 O-okayama, Meguro-ku, Tokyo 152-8552 (Japan); Department of Materials Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510 (Japan); Sannomiya, T.; Matsukawa, Y.; Muraishi, S.; Shi, J.; Nakamura, Y. [Department of Metallurgy and Ceramics Science, Tokyo Institute of Technology, 2-12-1-S8-6 O-okayama, Meguro-ku, Tokyo 152-8552 (Japan); Sawada, H. [Japan Electron Optics Laboratory (JEOL) Ltd., 3-1-2 Musashino, Akishima, Tokyo 196-8558 (Japan); Tanaka, T.; Tanishiro, Y.; Takayanagi, K. [Department of Physics, Tokyo Institute of Technology, 2-12-1-H-51 O-okayama, Meguro-ku, Tokyo 152-8551 (Japan)

    2013-02-28T23:59:59.000Z

    The polarity determination process of sputter-deposited aluminum nitride (AlN) on metals has been analyzed using aberration corrected atomic resolution scanning transmission electron microscope. Direct growth of c-axis orientated AlN on face centered cubic metals (fcc) (111) with the local epitaxy has been observed, and the polarity was determined at the AlN/metal interface. We found that the AlN polarity can be controlled by the base metal layer: N-polarity AlN grows on Pt(111) while Al-polarity AlN forms on Al(111). Based on these results, the growth mechanism of AlN on metals is discussed.

  9. Ultrafast transmission electron microscopy on dynamic process of a CDW transition in 1T-TaSe2

    E-Print Network [OSTI]

    Sun, Shuaishuai; Li, Zhongwen; Cao, Gaolong; Liu, Y; Lu, W J; Sun, Y P; Tian, Huanfang; HuaixinYang,; Li, Jianqi

    2015-01-01T23:59:59.000Z

    Four-dimensional ultrafast transmission electron microscopy (4D-UTEM) measurements reveal a rich variety of structural dynamic phenomena at a phase transition in the charge-density-wave (CDW) 1T-TaSe2. Through the photoexcitation, remarkable changes on both the CDW intensity and orientation are clearly observed associated with the transformation from a commensurate (C) into an incommensurate (IC) phase in a time-scale of about 3 ps. Moreover, the transient states show up a notable "structurally isosbestic point" at a wave vector of qiso where the C and IC phases yield their diffracting efficiencies in an equally ratio. This fact demonstrates that the crystal planes parallel to qiso adopts visibly common structural features in these two CDW phases. The second-order characters observed in this nonequilibrium phase transition have been also analyzed based on the time-resolved structural data.

  10. In situ observation on hydrogenation of Mg-Ni films using environmental transmission electron microscope with aberration correction

    SciTech Connect (OSTI)

    Matsuda, Junko, E-mail: junko.matsuda@i2cner.kyushu-u.ac.jp [International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Yoshida, Kenta [Institute for Advanced Research, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Nanostructures Research Laboratory, The Japan Fine Ceramics Center, 2-4-1 Mutsuno, Atsuta-ku, Nagoya 456-8587 (Japan); Sasaki, Yukichi [Nanostructures Research Laboratory, The Japan Fine Ceramics Center, 2-4-1 Mutsuno, Atsuta-ku, Nagoya 456-8587 (Japan); Uchiyama, Naoki [ATSUMITEC CO., LTD., Ubumi 7111, Yuto-cho, Nishi-ku, Hamamatsu 431-0192 (Japan); Akiba, Etsuo [International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Department of Mechanical Engineering, Faculty of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan)

    2014-08-25T23:59:59.000Z

    In situ transmission electron microscopy (TEM) was performed to observe the hydrogenation of Mg-Ni films in a hydrogen atmosphere of 80–100?Pa. An aberration-corrected environmental TEM with a differential pumping system allows us to reveal the Angstrom-scale structure of the films in the initial stage of hydrogenation: first, nucleation and growth of Mg{sub 2}NiH{sub 4} crystals with a lattice spacing of 0.22?nm in an Mg-rich amorphous matrix of the film occurs within 20 s after the start of the high-resolution observation, then crystallization of MgH{sub 2} with a smaller spacing of 0.15?nm happens after approximately 1?min. Our in situ TEM method is also applicable to the analysis of other hydrogen-related materials.

  11. Direct Visualization of Solid Electrolyte Interphase Formation in Lithium-Ion Batteries with In Situ Electrochemical Transmission Electron Microscopy

    SciTech Connect (OSTI)

    Unocic, Raymond R [ORNL] [ORNL; Sun, Xiao-Guang [ORNL] [ORNL; Sacci, Robert L [ORNL] [ORNL; Adamczyk, Leslie A [ORNL] [ORNL; Alsem, Daan Hein [Hummingbird Scientific] [Hummingbird Scientific; Dai, Sheng [ORNL] [ORNL; Dudney, Nancy J [ORNL] [ORNL; More, Karren Leslie [ORNL] [ORNL

    2014-01-01T23:59:59.000Z

    Complex, electrochemically driven transport processes form the basis of electrochemical energy storage devices. The direct imaging of electrochemical processes at high spatial resolution and within their native liquid electrolyte would significantly enhance our understanding of device functionality, but has remained elusive. In this work we use a recently developed liquid cell for in situ electrochemical transmission electron microscopy to obtain insight into the electrolyte decomposition mechanisms and kinetics in lithium-ion (Li-ion) batteries by characterizing the dynamics of solid electrolyte interphase (SEI) formation and evolution. Here we are able to visualize the detailed structure of the SEI that forms locally at the electrode/electrolyte interface during lithium intercalation into natural graphite from an organic Li-ion battery electrolyte. We quantify the SEI growth kinetics and observe the dynamic self-healing nature of the SEI with changes in cell potential.

  12. Electron line shape and transmission function of the KATRIN monitor spectrometer

    SciTech Connect (OSTI)

    Slezák, M. [Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 12116 Prague, Czech Republic and Nuclear Physics Institute, Academy of Sciences of the Czech Republic, Hlavní 130, 25068 ?ež (Czech Republic)

    2013-12-30T23:59:59.000Z

    Knowledge of the neutrino mass is of particular interest in modern neutrino physics. Besides the neutrinoless double beta decay and cosmological observation information about the neutrino mass is obtained from single beta decay by observing the shape of the electron spectrum near the endpoint. The KATRIN ? decay experiment aims to push the limit on the effective electron antineutrino mass down to 0.2 eV/c{sup 2}. To reach this sensitivity several systematic effects have to be under control. One of them is the fluctuations of the absolute energy scale, which therefore has to be continuously monitored at very high precision. This paper shortly describes KATRIN, the technique for continuous monitoring of the absolute energy scale and recent improvements in analysis of the monitoring data.

  13. Recent Progress in Chromatic Aberration Corrected High-Resolution and Lorentz Transmission Electron Microscopy

    E-Print Network [OSTI]

    Dunin-Borkowski, Rafal E.

    80 and 65 pm detail at 80 and 300 kV, respectively. Figure 2 shows CC and CS corrected energy. 58 (2009) 147. [3] R. Leary and R. Brydson. Advances in Imaging and Electron Physics 165 (2011) 73. The smallest detected image spacing at 80 kV (left) is ~80 pm and at 300 kV (right) is ~65 pm. FIG. 2. Atomic

  14. Photoinduced electron transfer reactions in zeolite cages. Progress report, January 15, 1990--August 1, 1992

    SciTech Connect (OSTI)

    Dutta, P.K.

    1992-12-31T23:59:59.000Z

    This report summarizes work in the two areas of zeolites and layered double hydroxides. Results of studies on structural aspects of Ru(bpy){sub 3}{sup 2+}-zeolite Y are summarized. Photoinduced electron transfer between entrapped Ru(bpy){sub 3}{sup 2+} and methylviologen (MV) in neighboring supercages was examined. Benzylviologen was also used. Since molecules larger than 13 {angstrom} cannot be accomodated in zeolite cages, the layered double metal hydroxides (LDH) LiAl{sub 2}(OH){sub 6}{sup +}X{sup {minus}} is being investigated. Organized assemblies of hydrophobic domains are made by introducing into the interlayer long-chain carboxylic acids R(CH{sub 2}){sub n}COOH. Zinc tetraphenylporphyrin sulfonate (ZnTPPS) is introduced into myristate-LiAl-LDH; photolysis of ZnTPPS-AiAl-LDH with MV{sup 2+} in solution was examined.

  15. Free energy, entropy and volume of activation for electron transfer reactions in a polar solvent

    SciTech Connect (OSTI)

    Manjari, Swati R.; Kim, Hyung J. [Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States)

    2006-07-07T23:59:59.000Z

    A continuum theory with account of cavity size fluctuations is employed to study free energy, volume and entropy of activation for nonadiabatic electron transfer (ET) reactions in polar solvents. By using a two-sphere cavity description, model calculations are performed for charge separation and recombination processes in acetonitrile under ambient conditions. It is found that the cavity size at the transition state varies with the free energy of reaction as well as with the thermodynamic conditions. In contrast to the Marcus theory predictions, the volume and entropy of activation show a monotonic behavior with the free energy of reaction and a strong correlation with each other. For example, for a given ET process, the volume and entropy of activation have the same sign. Their values for the charge separation and recombination processes are opposite in sign. These findings are in good qualitative agreement with measurements.

  16. Unusual mechanism for the short-range electron transfer within gold-alkanethiol-ionic-liquid films of subnanometer thickness

    SciTech Connect (OSTI)

    Khoshtariya, Dimitri E. [Department of Physics and Institute for Biophysics and Bionanosciences, I. Javakhishvili Tbilisi State University, I. Chavchavadze Avenue 3, 0128 Tbilisi, Georgia (United States); Department of Chemistry and Pharmacy, University of Erlangen-Nuernberg, Egerlandstrasse 1, 91058 Erlangen (Germany); Institute of Molecular Biology and Biophysics and Institute of Inorganic Chemistry and Electrochemistry, Gotua 12, 0160 Tbilisi, Georgia (United States); Dolidze, Tina D. [Department of Chemistry and Pharmacy, University of Erlangen-Nuernberg, Egerlandstrasse 1, 91058 Erlangen (Germany); Institute of Molecular Biology and Biophysics and Institute of Inorganic Chemistry and Electrochemistry, Gotua 12, 0160 Tbilisi, Georgia (United States); Eldik, Rudi van [Department of Chemistry and Pharmacy, University of Erlangen-Nuernberg, Egerlandstrasse 1, 91058 Erlangen (Germany)

    2009-12-15T23:59:59.000Z

    Exploiting nanoscopically tunable composite gold-alkanethiol-ionic-liquid/ferrocene self-assembled systems with tunable electron transfer distance, we discovered in the case of thinner alkanethiol films a thermally activated electron transfer pattern totally controlled by the viscosity-related slow relaxation mode(s) of the ionic liquid acting as the reactant's fluctuating environment. This pattern manifested through the activation enthalpy and volume parameters that are identical to those for viscous flow was explained in terms of the extreme adiabatic mechanism with a vanishing Marcus barrier (via the exponential Franck-Condon-like term approaching unity).

  17. Electron transfer reactions in microporous solids. Progress report, June 1991--May 1992

    SciTech Connect (OSTI)

    Mallouk, T.E.

    1992-05-01T23:59:59.000Z

    We have studied electron transfer quenching of the excited state of Ru(bpy){sub 3}{sup 2+} in aqueous suspensions of zeolites Y, L, and mordenite. The internal pore network of the zeolite is ion-exchanged with methylviologen cations, which quench the excited state of the surface-bound sensitizer. A detailed study of the quenching and charge recombination kinetics, using time-resolved luminescence quenching and transient diffuse reflectance spectroscopies, shows to remarkable effects: first, the excited state quenching is entirely dynamic is large-pore zeolites (L and Y), even when they are prepared as apparently ``dry`` powders (which still contain significant amounts of internally sited water). Second, a lower limit for the diffusion coefficient of the MV{sup 2+} ion in these zeolites, determined by this technique, is 10{sup {minus}7} cm{sup 2}sec, i.e., only about one order of magnitude slower than a typical ion in liquid water, and 2--3 orders of magnitude faster than charge transfer diffusion of cations in polyelectrolyte films or membranes such as Nafion. Surface sensitization of internally platinized layered oxide semiconductors such as K{sub 4-x}H{sub x}Nb{sub 6}O{sub 17}{center_dot}nH{sub 2}O (x {approx} 2.5) yields photocatalysts for the production of H{sub 2} and I{sub 3{minus}} in aqueous iodide solutions. Layered alkali niobates and titanates form a class of zeolitic wide-bandap semiconductors, and are the first examples of photocatalysts that evolve hydrogen from an electrochemically reversible (i.e., non-sacrificial) electron donor with visible light excitation.

  18. Cs-Exchange in Birnessite: Raction Mechanisms Inferred from Time-Resolved X-ray Diffraction and Transmission Electron Microscopy

    SciTech Connect (OSTI)

    Lopano, C.; Heaney, P; Post, J

    2009-01-01T23:59:59.000Z

    We have explored the exchange of Cs for interlayer Na in birnessite using several techniques, including transmission electron microscopy (TEM) and time-resolved synchrotron X-ray diffraction (XRD). Our goal was to test which of two possible exchange mechanisms is operative during the reaction: (1) diffusion of cations in and out of the interlayer or (2) dissolution of Na-birnessite and reprecipitation of Cs-birnessite. The appearance of distinct XRD peaks for Na- and Cs-rich phases in partially exchanged samples offered support for a simple diffusion model, but it was inconsistent with the compositional and crystallographic homogeneity of (Na,Cs)-birnessite platelets from core to rim as ascertained by TEM. Time-resolved XRD revealed systematic changes in the structure of the emergent Cs-rich birnessite phase during exchange, in conflict with a dissolution and reprecipitation model. Instead, we propose that exchange occurred by sequential delamination of Mn oxide octahedral sheets. Exfoliation of a given interlayer region allowed for wholesale replacement of Na by Cs and was rapidly followed by reassembly. This model accounts for the rapidity of metal exchange in birnessite, the co-existence of distinct Na- and Cs-birnessite phases during the process of exchange, and the uniformly mixed Na- and Cs-compositions ascertained from point analyses by selected area electron diffraction and energy dispersive spectroscopy of partially exchanged grains.

  19. In-situ Study of Dynamic Phenomena at Metal Nanosolder Interfaces Using Aberration Corrected Scanning Transmission Electron Microcopy.

    SciTech Connect (OSTI)

    Lu, Ping

    2014-10-01T23:59:59.000Z

    Controlling metallic nanoparticle (NP) interactions plays a vital role in the development of new joining techniques (nanosolder) that bond at lower processing temperatures but remain viable at higher temperatures. The pr imary objective of this project is t o develop a fundamental understanding of the actual reaction processes, associated atomic mechanisms, and the resulting microstructure that occur during thermally - driven bond formation concerning metal - metal nano - scale (<50nm) interfaces. In this LDRD pr oject, we have studied metallic NPs interaction at the elevated temperatures by combining in - situ transmission electron microscopy (TEM ) using an aberration - corrected scanning transmission electron microscope (AC - STEM) and atomic - scale modeling such as m olecular dynamic (MD) simulations. Various metallic NPs such as Ag, Cu and Au are synthesized by chemical routines. Numerous in - situ e xperiments were carried out with focus of the research on study of Ag - Cu system. For the first time, using in - situ STEM he ating experiments , we directly observed t he formation of a 3 - dimensional (3 - D) epitaxial Cu - Ag core - shell nanoparticle during the thermal interaction of Cu and Ag NPs at elevated temperatures (150 - 300 o C). The reaction takes place at temperatures as low as 150 o C and was only observed when care was taken to circumvent the effects of electron beam irradiation during STEM imaging. Atomic - scale modeling verified that the Cu - Ag core - shell structure is energetically favored, and indicated that this phenomenon is a nano - scale effect related to the large surface - to - volume ratio of the NPs. The observation potentially can be used for developing new nanosolder technology that uses Ag shell as the %22glue%22 that stic ks the particles of Cu together. The LDRD has led to several journal publications and numerous conference presentations, and a TA. In addition, we have developed new TEM characterization techniques and phase - field modeling tools that can be used for future materials research at Sandia. Acknowledgeme nts This work was supported by the Laboratory Directed Research and Development (LDRD) program of Sandia National Laboratories. Sandia National Laboratories is a multi - program laboratory managed and operated by Sandia Corporation, a wholly owned subsidia ry of Lockheed Martin Corporation, for the US Department of Energy's National Nuclear Security Administration under contract DE - AC04 - 94AL85000.

  20. Electron-transfer photochemistry of thianthrene. Nucleophile-assisted photooxidation to sulfoxide

    SciTech Connect (OSTI)

    Jones, G. II; Huang, B.; Griffin, S.F. (Boston Univ., MA (United States))

    1993-04-09T23:59:59.000Z

    The photochemistry of thianthrene (1) in the presence of a variety of electron acceptors in acetonitrile/water has been investigated. Diffusion-limited rates of fluorescence quenching were observed on excitation of 1 (with fumaronitrile and with methyl phthalate). Alternatively, addition of 1 led to quenching of the fluorescence emission of ketones, biacetyl, and fluorenone and to the quenching of the excited triplet states of quinones such as 2,5-dichloro-p-benzoquinone (5) and 9,10-anthraquinone (3). Steady irradiation of 1 with selected acceptors results in photooxidation yielding the sulfoxide (2) and the expected photoreduction products. The electron-transfer mechanisms were further studied by laser flash photolysis. The quenching of ketone triplets by 1 resulted in formation of the radical cation of 1([lambda][sub max]540 nm). The decay of this species and its dependence on the concentration of water present were determined; the bimolecular rate constant for trapping of 1[sup [center dot]+] by water in acetonitrile-water solution is 4.9 x 10[sup 4] M[sup [minus]1]s[sup [minus]1] under conditions in which 5 acts as a sensitizer. The nucleophilic trapping of the 1 radical cation by imidazole ([kappa] = 3.6 x 10[sup 7] M[sup [minus]1] s[sup [minus]1]) was also investigated. The mechanism of photoinduced two-electron oxidation of 1 and the role played by nucleophiles in facilitating the reaction are discussed in detail. 37 refs., 9 figs., 2 tabs.

  1. Characterization of host phases for actinides in simulated metallic waste forms by transmission electron microscopy.

    SciTech Connect (OSTI)

    Janney, D. E.

    2005-11-21T23:59:59.000Z

    Argonne National Laboratory has developed an electrometallurgical process for conditioning spent sodium-bonded metallic reactor fuel prior to disposal. A waste stream from this process consists of stainless steel cladding hulls that contain undissolved metal fission products such as Tc, Ru, Rh, Pd, and Ag; a small amount of undissolved actinides (U, Np, Pu) also remains with the hulls. These wastes will be immobilized in a waste form whose baseline composition is stainless steel alloyed with 15 wt% Zr (SS-15Zr). Scanning electron microscope (SEM) observations of simulated metal waste forms (SS-15Zr with added actinides) show eutectic intergrowths of iron solid-solution (''steel'') and Fe-Zr-Cr-Ni (''intermetallic'') materials. The actinide elements are almost entirely in the intermetallic materials, where they occur in concentrations as high as 20 at%. Neutron- and electron-diffraction studies of the simulated waste forms show materials with structures similar to those of Fe{sub 2}Zr and Fe{sub 23}Zr{sub 6}. New TEM observations of simulated waste form samples with compositions SS-15Zr-2Np, SS-15Zr-5U, SS-15Zr-11U-0.6Ru-0.3Tc-0.1Pd, and SS-15Zr-10Pu suggest that the major U- and Pu-bearing phase has a structure similar to that of the C15 (cubic, MgCu{sub 2}-type) polymorph of Fe{sub 2}Zr. Materials with this structure exhibit significant variability in chemical compositions and actinide concentrations up to 20 at% (normalized so that atomic fractions of Cr, Ni, Fe, and Zr add up to 1). A U-bearing material similar to the C36 (dihexagonal, MgNi{sub 2}-type) polymorph of Fe{sub 2}Zr was also observed. Chemical variability in materials with the C36 Fe{sub 2}Zr structure is smaller than in those with the C15 Fe{sub 2}Zr structure, and U concentrations are less than 5 at%. Uranium concentrations up to 5 at.% were observed in materials with the Fe{sub 23}Zr{sub 6} (cubic, Mn{sub 23}Th{sub 6}-type) structure. Microstructures similar to those produced during experimental deformation of Fe-10 at% Zr alloys were observed in intermetallic materials in all of the simulated waste form samples. Stacking faults and associated dislocations are common in samples with U, but rarely observed in those with Np and Pu, while twins occur in all samples. Previously reported differences in dissolution behavior between samples with different actinides may be related to increased defect-assisted dissolution in samples with U.

  2. 1856 IEEE TRANSACTIONS ON ELECTRON DEVICES, VOL. 57, NO. 8, AUGUST 2010 Harvesting and Transferring Vertical Pillar Arrays of

    E-Print Network [OSTI]

    Islam, M. Saif

    1856 IEEE TRANSACTIONS ON ELECTRON DEVICES, VOL. 57, NO. 8, AUGUST 2010 Harvesting and Transferring Vertical Pillar Arrays of Single-Crystal Semiconductor Devices to Arbitrary Substrates Logeeswaran VJ, Aaron M. Katzenmeyer, and M. Saif Islam Abstract--Development of devices that can be fabricated

  3. Inner-Sphere Electron-Transfer Single Iodide Mechanism for Dye Regeneration in Dye-Sensitized Solar Cells

    E-Print Network [OSTI]

    Goddard III, William A.

    the regeneration of the oxidized dye in dye-sensitized solar cells, the redox couple of I- /I3 - reduces the photo dye- sensitized solar cell (DSSC) in 1991,1 DSSCs have been considered as promising alternativesInner-Sphere Electron-Transfer Single Iodide Mechanism for Dye Regeneration in Dye-Sensitized Solar

  4. Evidence of electron-transfer in the SERS spectra of a single iron-protoporphyrin IX molecule

    E-Print Network [OSTI]

    Tuscia, Università Degli Studi Della

    cooperating mechanisms: the electromagnetic enhancement (EM) ef- fect associated with an enhanced local field Raman mechanisms and the interfacial electron transfer in hybrid systems. Ó 2004 Elsevier B.V. All- action with the surrounding environment, might be used to locally monitor specific processes at molecular

  5. Ultrafast heterogeneous electron transfer reactions: Comparative theoretical studies on time- and frequency-domain data

    SciTech Connect (OSTI)

    Wang Luxia; Willig, Frank; May, Volkhard [Institut fuer Physik, Humboldt-Universitaet zu Berlin, Newtonstrasse 15, D-12489 Berlin (Germany); Hahn-Meitner-Institut, Abteilung Dynamik von Genzflaechenreaktionen, Glienicker Strasse 100, 14109 Berlin (Germany); Institut fuer Physik, Humboldt-Universitaet zu Berlin, Newtonstrasse 15, D-12489 Berlin (Germany)

    2006-01-07T23:59:59.000Z

    Recent theoretical studies on linear absorption spectra of dye-semiconductor systems [perylene attached to nanostructured TiO{sub 2}, L. Wang et al., J. Phys. Chem. B 109, 9589 (2005)] are extended here in different respects. Since the systems show ultrafast photoinduced heterogeneous electron transfer the time-dependent formulation used to compute the absorbance is also applied to calculate the temporal evolution of the sub-100 fs charge injection dynamics after a 10 fs laser-pulse excitation. These studies complement our recent absorption spectra fit for two perylene bridge-anchor group TiO{sub 2} systems. Moreover, the time-dependent formulation of the absorbance is confronted with a frequency-domain description. The latter underlines the central importance of the self-energy caused by the coupling of the dye levels to the semiconductor band continuum. The used model is further applied to study the effect of different parameters such as (1) the dependence on the reorganization energies of the involved intramolecular transitions, (2) the effect of changing the transfer integral which couples the excited dye state with the band continuum, and (3) the effect of the concrete form of the semiconductor band density of states. Emphasis is also put on the case where the charge injection level of the dye is near or somewhat below the band edge. This nicely demonstrates the change from a structureless absorption to a well-resolved vibrational progression including characteristic shifts of the absorption lines which are a direct measure for the dye-semiconductor coupling.

  6. Monitoring Long-Range Electron Transfer Pathways in Proteins by Stimulated Attosecond Broadband X-ray Raman Spectroscopy

    SciTech Connect (OSTI)

    Zhang, Yu; Biggs, Jason; Govind, Niranjan; Mukamel, Shaul

    2014-10-09T23:59:59.000Z

    Long-range electron transfer (ET) plays a key role in many biological energy conversion and synthesis processes. We show that nonlinear spectroscopy with attosecond X-ray pulses provides a real time movie of the evolving oxidation states and electron densities around atoms, and can probe these processes with high spatial and temporal resolution. This is demonstrated in a simulation study of the stimulated X-ray Raman (SXRS) signals in Re-modified azurin, which had long served as a benchmark for long-range ET in proteins. Nonlinear SXRS signals are sensitive to the local electronic structure and should offer a novel window for long-range ET.

  7. Proton-coupled electron transfer at the Qo-site of the bc1 complex controls the rate of ubihydroquinone oxidation.

    E-Print Network [OSTI]

    Crofts, Antony R.

    1 Proton-coupled electron transfer at the Qo-site of the bc1 complex controls the rate transfer; proton transfer; bc1 complex; Qo-site; Marcus theory; ES-complex Abbreviations: bc1 complex of the transmembrane proton gradient is positive or negative, respectively; PDB#, Protein Data Bank identifier; Q

  8. Abstract--The increase in use of power electronics in transmission and distribution applications is the driving

    E-Print Network [OSTI]

    Tolbert, Leon M.

    is the driving force for development of high power devices. Utility applications like FACTS and HVDC require cost and compared for SiC and Si devices. These loss models are integrated with an HVDC transmission system to study of the systems. High Voltage DC (HVDC) transmission and Flexible AC Transmission Systems (FACTS) are the widely

  9. Surface plasmon enhanced interfacial electron transfer and resonance Raman, surface-enhanced resonance Raman studies of cytochrome C mutants

    SciTech Connect (OSTI)

    Zheng, Junwei

    1999-11-08T23:59:59.000Z

    Surface plasmon resonance was utilized to enhance the electron transfer at silver/solution interfaces. Photoelectrochemical reductions of nitrite, nitrate, and CO{sub 2} were studied on electrochemically roughened silver electrode surfaces. The dependence of the photocurrent on photon energy, applied potential and concentration of nitrite demonstrates that the photoelectrochemical reduction proceeds via photoemission process followed by the capture of hydrated electrons. The excitation of plasmon resonances in nanosized metal structures resulted in the enhancement of the photoemission process. In the case of photoelectrocatalytic reduction of CO{sub 2}, large photoelectrocatalytic effect for the reduction of CO{sub 2} was observed in the presence of surface adsorbed methylviologen, which functions as a mediator for the photoexcited electron transfer from silver metal to CO{sub 2} in solution. Photoinduced reduction of microperoxidase-11 adsorbed on roughened silver electrode was also observed and attributed to the direct photoejection of free electrons of silver metal. Surface plasmon assisted electron transfer at nanostructured silver particle surfaces was further determined by EPR method.

  10. Photofragmentation in linked donor-acceptor molecules. Intramolecular single electron transfer induced cleavage of a 1,2-diamine

    SciTech Connect (OSTI)

    Leon, J.W.; Whitten, D.G. (Univ. of Rochester, NY (United States))

    1993-09-08T23:59:59.000Z

    Two intramolecular donor-acceptor molecules which fragment by a single electron transfer initiated cation radical carbon-carbon bond cleavage have been synthesized and their photoreactivity studied. The intramolecular [open quotes]diads[close quotes] consist of a 1,2-diamine linked via an ester bond to either an anthraquinone or a 9,10-dicyanoanthracene electron-acceptor chromophore. As the covalent linkage between the donor and acceptor chromophores prevents solvent separation of the photogenerated radical ion pair, these systems provide a [open quotes]clock[close quotes] to examine directly competition between fragmentation and back electron transfer. The linked anthraquinone molecule fragments efficiently, with quantum yields approaching 80%, despite the inability of the photoproduced radical ions to separate. These high yields may be attributed to a slow, spin-forbidden back electron transfer and a rapid fragmentation. In contrast, the quantum yields for the dicyanoanthracene diad (reactive singlet) are markedly lower, less than 0.001 in benzene. The reactivity of comparable intermolecular donor-acceptor combinations is also reported. 54 refs., 3 figs., 2 tabs.

  11. Transmission Workshop

    Broader source: Energy.gov (indexed) [DOE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOn April 23,EnergyChicopeeTechnologyfact sheetTransferring the Wayne,TRANSMISSION WORKSHOP

  12. Electron Transfer to SF6 and Oriented CH3Br Sean A. Harris, Susan D. Wiediger, and Philip R. Brooks*

    E-Print Network [OSTI]

    Brooks, Philip R.

    ARTICLES Electron Transfer to SF6 and Oriented CH3Br Sean A. Harris, Susan D. Wiediger, and Philip in collisions of unoriented SF6 and oriented CH3Br. For lab energies 5-30 eV, Br- is the only ion observed from the same energetic threshold for forming Br- . SF5 - , SF6 - , and F- ions are observed from SF6 and O2

  13. Transmission electron microscopy (TEM) investigations of Mn-oxide rich cathodic material from spent disposable alkaline batteries

    SciTech Connect (OSTI)

    Krekeler, Mark P.S. [Department of Environmental Science and Policy, George Mason University, Fairfax, VA 22030 (United States)], E-mail: mark.krekeler@gmail.com

    2008-11-15T23:59:59.000Z

    Transmission electron microscopy (TEM) techniques were used to investigate the spent cathodic material of a single common brand of disposable alkaline batteries. Mn-oxide particles are anhedral and irregular in shape and compose an estimated 99-95% of the <10 {mu}m size fraction of sample material. Diameters of particles vary widely and typically are between 50 nm and 3 {mu}m; however, most particles are approximately 200-400 nm in diameter. Chemical composition varies for Mn-oxide particles with concentrations being SiO{sub 2} (0.00-1.52 wt%), TiO{sub 2} (0.49-4.58 wt%), MnO (65.85-92.06 wt%), ZnO (1.00-7.53 wt%), K{sub 2}O (4.97-20.48 wt%) and SO{sub 3} (0.43-2.21 wt%). Discrete prismatic zinc crystals occur and vary from a maximum of approximately 0.8 {mu}m long x 0.15 {mu}m wide, to 100 nm long x 20 nm wide. Titanium metal was also observed in samples and composes approximately 0.25-1.0% of the <10 {mu}m size fraction of sample material. Results of this study suggest that battery components may be recycled in some special applications. Examples are low energy-low material requirement products such as paint pigments and Zn nanoparticles. This investigation provides detailed constraints on the nature of spent cathodic materials to improve existing recycling methods and develop new technologies.

  14. Rapid Laser Induced Crystallization of Amorphous NiTi Films Observed by Nanosecond Dynamic Transmission Electron Microscopy (DTEM)

    SciTech Connect (OSTI)

    LaGrange, T; Campbell, G H; Browning, N D; Reed, B W; Grummon, D S

    2010-03-01T23:59:59.000Z

    The crystallization processes of the as-deposited, amorphous NiTi thin films have been studied in detail using techniques such as differential scanning calorimetry and, in-situ TEM. The kinetic data have been analyzed in terms of Johnson-Mehl-Avrami-Kolomogrov (JMAK) semi-empirical formula. The kinetic parameters determined from this analysis have been useful in defining process control parameters for tailoring microstructural features and shape memory properties. Due to the commercial push to shrink thin film-based devices, unique processing techniques have been developed using laser-based annealing to spatially control the microstructure evolution down to sub-micron levels. Nanosecond, pulse laser annealing is particularly attractive since it limits the amount of peripheral heating and unwanted microstructural changes to underlying or surrounding material. However, crystallization under pulsed laser irradiation can differ significantly from conventional thermal annealing, e.g., slow heating in a furnace. This is especially true for amorphous NiTi materials and relevant for shape memory thin film based microelectromechanical systems (MEMS) applications. There is little to no data on the crystallization kinetics of NiTi under pulsed laser irradiation, primarily due to the high crystallization rates intrinsic to high temperature annealing and the spatial and temporal resolution limits of standard techniques. However, with the high time and spatial resolution capabilities of the dynamic transmission electron microscope (DTEM) constructed at Lawrence Livermore National Laboratory, the rapid nucleation events occurring from pulsed laser irradiation can be directly observed and nucleation rates can be quantified. This paper briefly explains the DTEM approach and how it used to investigate the pulsed laser induced crystallization processes in NiTi and to determine kinetic parameters.

  15. Application of Momentum Transfer Theory for Ion and Electron Transport in Pure Gases and in Gas Mixtures

    SciTech Connect (OSTI)

    Jovanovic, J.V. [Institute of Physics, P.O.Box 68, 11080 Zemun, Belgrade (Serbia and Montenegro); Faculty of Mechanical Engineering, 11000 Belgrade (Serbia and Montenegro); Vrhovac, S. B. [Institute of Physics, P.O.Box 68, 11080 Zemun, Belgrade (Serbia and Montenegro)

    2004-12-01T23:59:59.000Z

    In this paper we have presented two applications of Momentum Transfer Theory (MTT), which were both aimed at obtaining reliable data for modeling of non-equilibrium plasma. Transport properties of ion swarms in presence of Resonant Charge Transfer (RCT) collisions are studied using Momentum Transfer Theory (MTT). Using the developed MTT we tested a previously available anisotropic set of cross-sections for Ar++Ar collisions bay making the comparisons with the available data for the transverse diffusion coefficient. We also developed an anisotropic set of Ne++Ne integral cross-sections based on the available data for mobility, longitudinal and transverse diffusion. Anisotropic sets of cross-sections are needed for Monte Carlo simulations of ion transport and plasma models. Application of Blanc's Law for drift velocities of electrons and ions in gas mixtures at arbitrary reduced electric field strengths E/n0 was studied theoretically and by numerical examples. Corrections for Blanc's Law that include effects of inelastic collisions were derived. In addition we have derived the common mean energy procedure that was proposed by Chiflikian in a general case both for ions and electrons. Both corrected common E/n0 and common mean energy procedures provide excellent results even for electrons at moderate E/n0 where application of Blanc's Law was regarded as impossible. In mixtures of two gases that have negative differential conductivity (NDC) even when neither of the two pure gases show NDC the Blanc's Law procedure was able to give excellent predictions.

  16. Transmission electron microscopy study on Co/Fe interdiffusion in SmCo5/Fe and Sm2Co7/Fe/Sm2Co7 thin films

    E-Print Network [OSTI]

    Liu, J. Ping

    Transmission electron microscopy study on Co/Fe interdiffusion in SmCo5/Fe and Sm2Co7/Fe/Sm2Co7 at the interface of an as-deposited SmCo5/Fe bilayer, while annealing results in measurable Co/Fe interdiffusion near the boundary. For the annealed SmCo5/Fe bilayer, phase separation occurs within the bcc

  17. Study of intermediates from transition metal excited-state electron-transfer reactions. [Annual] progress report, August 1, 1989--July 31, 1992

    SciTech Connect (OSTI)

    Hoffman, M.Z.

    1992-07-31T23:59:59.000Z

    Conventional and fast-kinetics techniques of photochemistry, photophysics, radiation chemistry, and electrochemistry were used to study the intermediates involved in transition metal excited-state electron-transfer reactions. These intermediates were excited state of Ru(II) and Cr(III) photosensitizers, their reduced forms, and species formed in reactions of redox quenchers and electron-transfer agents. Of particular concern was the back electron-transfer reaction between the geminate pair formed in the redox quenching of the photosensitizers, and the dependence of its rate on solution medium and temperature in competition with transformation and cage escape processes. (DLC)

  18. Solid State Electron Transfer via Bacterial Nanowires: Contributions Toward a Mechanistic Understanding of Geophysical Response of Biostimulated Subsurface

    SciTech Connect (OSTI)

    Estella Atekwana

    2012-05-08T23:59:59.000Z

    The degradation of organic matter by microorganisms provides a source of electrical potential or so-called 'self potential' (SP) that can be measured by using a voltmeter. During this process electrons are being produced as a waste-product and bacterial cells have to dispose of these to allow for the complete biodegradation of organic matter. Especially in anaerobic microbial communities, exo-cellular electron transfer is the most important driving force behind this process and organisms have developed different, but also similar, ways to transfer electrons to other microorganisms. Recently, it has been postulated that direct electron transfer from cell-to-cell is actually done by 'hard-wired' microorganisms. This shuttling of electrons is most likely done by certain c-type cytochromes that form the functional part of electrically conductive nanowires. In this study we investigated if nanowires can explain the geoelectrical (self potential and spectral induced polarization) signals observed at some biostimulated environments such as DOE sites. The objectives of our project are to: (1) investigate any temporal changes in the geophysical signatures (Self Potential (SP) and Induced Polarization (IP)) associated with nanowires of the bacterium Shewanella oneidensis MR-1, wild type and mtrc/omcA deletion mutant, (2) demonstrate that mutant strains of bacteria that produce nonconductive nanowires do not contribute to geoelectrical responses. We accomplished the following: (1) Provided training to students and a postdoctoral fellow that worked on the project, (2) Conducted several SP & IP measurements correlating the distribution of nanowires and SIP/SP signals in partial fulfillment of object No. 1 and 2. On the following we will report and discuss the results of our last experiment with some emphasis on the source mechanisms of both SP and IP associated with Shewanella oneidensis MR-1, wild type in sand columns.

  19. Kinetics and mechanism of bimolecular electron transfer reaction in quinone-amine systems in micellar solution

    SciTech Connect (OSTI)

    Kumbhakar, Manoj; Nath, Sukhendu; Mukherjee, Tulsi; Pal, Haridas [Radiation Chemistry and Chemical Dynamics Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)

    2005-02-22T23:59:59.000Z

    Photoinduced electron transfer (ET) reactions between anthraquinone derivatives and aromatic amines have been investigated in sodium dodecyl sulphate (SDS) micellar solutions. Significant static quenching of the quinone fluorescence due to high amine concentration in the micellar phase has been observed in steady-state measurements. The bimolecular rate constants for the dynamic quenching in the present systems k{sub q}{sup TR}, as estimated from the time-resolved measurements, have been correlated with the free energy changes {delta}G{sup 0} for the ET reactions. Interestingly it is seen that the k{sub q}{sup TR} vs {delta}G{sup 0} plot displays an inversion behavior with maximum k{sub q}{sup TR} at around 0.7 eV, a trend similar to that predicted in Marcus ET theory. Like the present results, Marcus inversion in the k{sub q}{sup TR} values was also observed earlier in coumarin-amine systems in SDS and TX-100 micellar solutions, with maximum k{sub q}{sup TR} at around the same exergonicity. These results thus suggest that Marcus inversion in bimolecular ET reaction is a general phenomenon in micellar media. Present observations have been rationalized on the basis of the two-dimensional ET (2DET) theory, which seems to be more suitable for micellar ET reactions than the conventional ET theory. For the quinone-amine systems, it is interestingly seen that k{sub q}{sup TR} vs {delta}G{sup 0} plot is somewhat wider in comparison to that of the coumarin-amine systems, even though the maxima in the k{sub q}{sup TR} vs {delta}G{sup 0} plots appear at almost similar exergonicity for both the acceptor-donor systems. These observations have been rationalized on the basis of the differences in the reaction windows along the solvation axis, as envisaged within the framework of the 2DET theory, and arise due to the differences in the locations of the quinones and coumarin dyes in the micellar phase.

  20. Effect of micellar environment on Marcus correlation curves for photoinduced bimolecular electron transfer reactions

    SciTech Connect (OSTI)

    Kumbhakar, Manoj; Nath, Sukhendu; Mukherjee, Tulsi; Pal, Haridas [Radiation Chemistry and Chemical Dynamics Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)

    2005-07-15T23:59:59.000Z

    Photoinduced electron transfer (ET) between coumarin dyes and aromatic amine has been investigated in two cationic micelles, namely, cetyltrimethyl ammonium bromide (CTAB) and dodecyltrimethyl ammonium bromide (DTAB), and the results have been compared with those observed earlier in sodium dodecyl sulphate (SDS) and triton-X-100 (TX-100) micelles for similar donor-acceptor pairs. Due to a reasonably high effective concentration of the amines in the micellar Stern layer, the steady-state fluorescence results show significant static quenching. In the time-resolved (TR) measurements with subnanosecond time resolution, contribution from static quenching is avoided. Correlations of the dynamic quenching constants (k{sub q}{sup TR}), as estimated from the TR measurements, show the typical bell-shaped curves with the free-energy changes ({delta}G{sup 0}) of the ET reactions, as predicted by the Marcus outersphere ET theory. Comparing present results with those obtained earlier for similar coumarin-amine systems in SDS and TX-100 micelles, it is seen that the inversion in the present micelles occurs at an exergonicity (-{delta}G{sup 0}>{approx}1.2-1.3 eV) much higher than that observed in SDS and TX-100 micelles (-{delta}G{sup 0}>{approx}0.7 eV), which has been rationalized based on the relative propensities of the ET and solvation rates in different micelles. In CTAB and DTAB micelles, the k{sub q}{sup TR} values are lower than the solvation rates, which result in the full contribution of the solvent reorganization energy ({lambda}{sub s}) towards the activation barrier for the ET reaction. Contrary to this, in SDS and TX-100 micelles, k{sub q}{sup TR} values are either higher or comparable with the solvation rates, causing only a partial contribution of {lambda}{sub s} in these cases. Thus, Marcus inversion in present cationic micelles is inferred to be the true inversion, whereas that in the anionic SDS and neutral TX-100 micelles are understood to be the apparent inversion, as envisaged from two-dimensional ET theory.

  1. Electron Transport and Scattering in Graphene Devices Transferred to SrTiO3 Substrates

    E-Print Network [OSTI]

    Sachs, Raymond

    2013-01-01T23:59:59.000Z

    graphene device on SiO 2 (left) and STO (right). 5.6 PreparationGraphene Field-Effect Transistor Devices . 67 5.4 Measurement Setup . 68 5.5 Device Transfer Technique .. 70 5.6 Preparation

  2. United States-Mexico electricity transfers: Of alien electrons and the migration of undocumented environmental burdens

    SciTech Connect (OSTI)

    Gandara, A. [Univ. of California, Davis, CA (United States)

    1995-08-01T23:59:59.000Z

    This article intends to set forth the necessity for reform in the United States policy and procedures regarding approval of power transfers between the United States and Mexico. In order to do this, the article will review the history of electrical power transfers between the United States and Mexico (Part II), analyze recent regulatory changes in the United States and Mexico which may result in increased power exports to Mexico (Part III), evaluate the extent to which the present permit and authorization system in the United States considers the increased environmental burden of such power transfers (Part IV), and, where appropriate, propose some procedural and policy reforms that could take into account the environmental burdens generated by the production of power destined for transfer across the United States-Mexico border (Part V).

  3. Development of a Proteoliposome Model to Probe Transmembrane Electron-Transfer Reactions

    SciTech Connect (OSTI)

    White, Gaye F.; Shi, Zhi; Shi, Liang; Dohnalkova, Alice; Fredrickson, Jim K.; Zachara, John M.; Butt, Julea N.; Richardson, David J.; Clarke, Thomas

    2012-12-01T23:59:59.000Z

    The mineral respiring bacterium Shewanella oneidensis uses a protein complex, MtrCAB, composed of two decaheme cytochromes brought together inside a transmembrane porin to transport electrons across the outer membrane to a variety of mineral-based electron acceptors. A proteoliposome system has been developed that contains methyl viologen (MV) as an internalised electron acceptor and valinomycin (V) as a membrane associated cation exchanger. These proteoliposomes can be used as a model system to investigate MtrCAB function.

  4. A trans-outer membrane porin-cytochrome protein complex for extracellular electron transfer by Geobacter sulfurreducens PCA

    SciTech Connect (OSTI)

    Liu, Yimo; Wang, Zheming; Liu, Juan; Levar, Caleb; Edwards, Marcus; Babauta, Jerome T.; Kennedy, David W.; Shi, Zhi; Beyenal, Haluk; Bond, Daniel R.; Clarke, Thomas A.; Butt, Julea N.; Richardson, David J.; Rosso, Kevin M.; Zachara, John M.; Fredrickson, Jim K.; Shi, Liang

    2014-09-24T23:59:59.000Z

    The multiheme, outer membrane c-type cytochrome (c-Cyt) OmcB of Geobacter sulfurreducens was previously proposed to mediate electron transfer across the outer membrane. However, the underlying mechanism has remained uncharacterized. In G. sulfurreducens, the omcB gene is part of two tandem four-gene clusters, each is predicted to encode a transcriptional factor (OrfR/OrfS), a porin-like outer membrane protein (OmbB/OmbC), a periplasmic c-type cytochrome (OmaB/OmaC), and an outer membrane c-Cyt (OmcB/OmcC), respectively. Here we showed that OmbB/OmbC, OmaB/OmaC and OmcB/OmcC of G. sulfurreducens PCA formed the porin-cytochrome (Pcc) protein complexes, which were involved in transferring electrons across the outer membrane. The isolated Pcc protein complexes reconstituted in proteoliposomes transferred electrons from reduced methyl viologen across the lipid bilayer of liposomes to Fe(III)-citrate and ferrihydrite. The pcc clusters were found in all eight sequenced Geobacter and 11 other bacterial genomes from six different phyla, demonstrating a widespread distribution of Pcc protein complexes in phylogenetically diverse bacteria. Deletion of ombB-omaB-omcB-orfS-ombC-omaC-omcC gene clusters had no impact on the growth of G. sulfurreducens PCA with fumarate, but diminished the ability of G. sulfurreducens PCA to reduce Fe(III)-citrate and ferrihydrite. Complementation with the ombB-omaB-omcB gene cluster restored the ability of G. sulfurreducens PCA to reduce Fe(III)-citrate and ferrihydrite.

  5. High-Affinity Binding and Direct Electron Transfer to Solid Metals...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    been suggested to function in concert with other membrane proteins as one of the terminal electron donors in the metal reductase protein complex of Shewanella oneidensis...

  6. Chemical Bonding: The Classical Description sharing or transferring electrons between atoms

    E-Print Network [OSTI]

    Ihee, Hyotcherl

    new arrangements of electrons with lower total potential energy than isolated atoms covalent ionic, actinides, metal, non-metal, semi-metal #12;IONIZATION ENERGY : a measure of the stability of the electron Existence of the SHELLExistence of the SHELL 3.2 Ionization Energies and the Shell Model of Atom #12

  7. Photoinduced Electron Transfer and Solvation in Iodide-doped Acetonitrile Clusters Oli T. Ehrler, Graham B. Griffin, Ryan M. Young, and Daniel M. Neumark*

    E-Print Network [OSTI]

    Neumark, Daniel M.

    Photoinduced Electron Transfer and Solvation in Iodide-doped Acetonitrile Clusters Oli T. Ehrler acetonitrile clusters I- (CH3CN)n with n ) 5-10. Strong modulations of vertical detachment energies were of the I atom leaving the cavity and rearrangement of the acetonitrile molecules to solvate the electron

  8. Blinking suppression of CdTe quantum dots on epitaxial graphene and the analysis with Marcus electron transfer

    SciTech Connect (OSTI)

    Hirose, Takuya; Tamai, Naoto, E-mail: tamai@kwansei.ac.jp [Department of Chemistry, School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo 669-1337 (Japan); Kutsuma, Yasunori; Kurita, Atsusi; Kaneko, Tadaaki [Department of Physics, School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo 669-1337 (Japan)

    2014-08-25T23:59:59.000Z

    We have prepared epitaxial graphene by a Si sublimation method from 4H-SiC. Single-particle spectroscopy of CdTe quantum dots (QDs) on epitaxial graphene covered with polyvinylpyrrolidone (PVP) or polyethylene glycol (PEG) showed the suppression of luminescence blinking and ?10 times decreased luminescence intensity as compared with those on a glass. The electronic coupling constant, H{sub 01}, between CdTe QDs and graphene was calculated to be (3.3?±?0.4)?×?10{sup 2?}cm{sup ?1} in PVP and (3.7?±?0.8)?×?10{sup 2?}cm{sup ?1} in PEG based on Marcus theory of electron transfer and Tang-Marcus model of blinking with statistical distribution.

  9. Nano-scale luminescence characterization of individual InGaN/GaN quantum wells stacked in a microcavity using scanning transmission electron microscope cathodoluminescence

    SciTech Connect (OSTI)

    Schmidt, Gordon, E-mail: Gordon.Schmidt@ovgu.de; Müller, Marcus; Veit, Peter; Bertram, Frank; Christen, Jürgen [Institute of Experimental Physics, Otto-von-Guericke-University Magdeburg, 39106 Magdeburg (Germany); Glauser, Marlene; Carlin, Jean-François; Cosendey, Gatien; Butté, Raphaël; Grandjean, Nicolas [Institute of Condensed Matter Physics, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland)

    2014-07-21T23:59:59.000Z

    Using cathodoluminescence spectroscopy directly performed in a scanning transmission electron microscope at liquid helium temperatures, the optical and structural properties of a 62 InGaN/GaN multiple quantum well embedded in an AlInN/GaN based microcavity are investigated at the nanometer scale. We are able to spatially resolve a spectral redshift between the individual quantum wells towards the surface. Cathodoluminescence spectral linescans allow directly visualizing the critical layer thickness in the quantum well stack resulting in the onset of plastic relaxation of the strained InGaN/GaN system.

  10. pH-Dependent Reduction Potentials and Proton-Coupled Electron Transfer Mechanisms in Hydrogen-Producing Nickel Molecular Electrocatalysts

    SciTech Connect (OSTI)

    Horvath, Samantha; Fernandez, Laura; Appel, Aaron M.; Hammes-Schiffer, Sharon

    2013-04-01T23:59:59.000Z

    The nickel-based Ph Bz 2 2 P N electrocatalysts, which are comprised of a nickel atom and two 1,5-dibenzyl-3,7-diphenyl-1,5-diaza-3,7-diphosphacyclooctane ligands, have been shown to effectively catalyze H2 production in acetonitrile. Recent electrochemical experiments revealed a linear dependence of the NiII/I reduction potential on pH, suggesting a proton-coupled electron transfer (PCET) reaction. In the proposed mechanism, the catalytic cycle begins with a PCET process involving electrochemical electron transfer to the nickel center and intermolecular proton transfer from an acid to the pendant amine ligand. This paper presents quantum mechanical calculations of this PCET process to examine the thermodynamics of the sequential mechanisms, in which either the electron or the proton transfers first (ET–PT and PT–ET, respectively), and the concerted mechanism (EPT). The favored mechanism depends on a balance among many factors, including the acid strength, association free energy for the acid–catalyst complex, PT free energy barrier, and ET reduction potential. The ET reduction potential is less negative after PT, favoring the PT–ET mechanism, and the association free energy is less positive after reduction, favoring the ET–PT mechanism. The calculations, along with analysis of the experimental data, indicate that the sequential ET–PT mechanism is favored for weak acids because of the substantial decrease in the association free energy after reduction. For strong acids, however, the PT–ET mechanism may be favored because the association free energy is somewhat smaller and PT is more thermodynamically favorable. The concerted mechanism could also occur, particularly for intermediate acid strengths. In the context of the entire catalytic cycle for H2 production, the initial PCET process involving intermolecular PT has a more negative reduction potential than the subsequent PCET process involving intramolecular PT. As a result, the second PCET should occur spontaneously, which is consistent with cyclic voltammogram experiments. This research was supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences.

  11. Final Report: The Impact of Carbonate on Surface Protonation, Electron Transfer and Crystallization Reactions in Iron Oxide Nanoparticles and Colloids

    SciTech Connect (OSTI)

    Dixon, David Adams [The University of Alabama

    2013-07-02T23:59:59.000Z

    This project addresses key issues of importance in the geochemical behavior of iron oxides and in the geochemical cycling of carbon and iron. For Fe, we are specifically studying the influence of carbonate on electron transfer reactions, solid phase transformations, and the binding of carbonate to reactive sites on the edges of particles. The emphasis on carbonate arises because it is widely present in the natural environment, is known to bind strongly to oxide surfaces, is reactive on the time scales of interest, and has a speciation driven by acid-base reactions. The geochemical behavior of carbonate strongly influences global climate change and CO{sub 2} sequestration technologies. Our goal is to answer key questions with regards to specific site binding, electron transfer reactions, and crystallization reactions of iron oxides that impact both the geochemical cycling of iron and CO{sub 2} species. Our work is focused on the molecular level description of carbonate chemistry in solution including the prediction of isotope fractionation factors. We have also done work on critical atmospheric species.

  12. Excited states and electron transfer in solution : models based on density functional theory

    E-Print Network [OSTI]

    Kowalczyk, Timothy Daniel

    2012-01-01T23:59:59.000Z

    Our understanding of organic materials for solar energy conversion stands to benefit greatly from accurate, computationally tractable electronic structure methods for excited states. Here we apply two approaches based on ...

  13. Theoretical and simulation tools for electron transfer and chain reactions in single walled carbon nanotubes

    E-Print Network [OSTI]

    Nair, Nitish

    2009-01-01T23:59:59.000Z

    Single walled carbon nanotubes (SWNT) are cylindrical sheets of graphene whose electronic structures and diameters are determined by their chiralities. Current synthetic methods produce batches of nanotubes containing a ...

  14. Photoelectrochemistry in particulate systems. 7. Electron-transfer reactions of indium sulfide semiconductor colloids

    SciTech Connect (OSTI)

    Kamat, P.V.; Dimitrijevic, N.M.; Fessenden, R.W.

    1988-04-21T23:59:59.000Z

    Small semiconductor colloids of In/sub 2/S/sub 3/ have been prepared in aqueous and nonaqueous media and their absorption properties characterized. A transient photobleaching and formation of S/sup .-/ and S/sub 2/H/sub 2//sup .-/ radicals have been observed upon laser pulse (355 nm) excitation of these colloids. With the aid of transient absorption spectra, the anodic corrosion process in these semiconductor colloids has been elucidated by using laser flash photolysis and pulse radiolysis techniques. With the use of a zwitterionic viologen compound, the interfacial charge-transfer process at the semiconductor surface has been studied. The quantum yield for the reduction of zwitterionic viologen was 0.07, which is similar to the value obtained with other metal chalcogenide semiconductor colloids. The microenvironment of the stabilizer (Nafion) influenced the charge-transfer process between the semiconductor and the redox decay.

  15. Nanowires, Capacitors, and Other Novel Outer-Surface Components Involved in Electron Transfer to Fe(III) Oxides in Geobacter Species

    SciTech Connect (OSTI)

    Lovley, Derek, R.

    2008-12-22T23:59:59.000Z

    The overall goal of this project was to better understand the mechanisms by which Geobacter species transfer electrons outside the cell onto Fe(III) oxides. The rationale for this study was that Geobacter species are often the predominant microorganisms involved in in situ uranium bioremediation and the growth and activity of the Geobacter species during bioremediation is primarily supported by electron transfer to Fe(III) oxides. These studies greatly expanded the understanding of electron transfer to Fe(III). Novel concepts developed included the potential role of microbial nanowires for long range electron transfer in Geobacter species and the importance of extracytoplasmic cytochromes functioning as capacitors to permit continued electron transfer during the hunt for Fe(III) oxide. Furthermore, these studies provided target sequences that were then used in other studies to tract the activity of Geobacter species in the subsurface through monitoring the abundance of gene transcripts of the target genes. A brief summary of the major accomplishments of the project is provided.

  16. High resolution low dose transmission electron microscopy real-time imaging and manipulation of nano-scale objects in the electron beam

    DOE Patents [OSTI]

    Brown, Jr., R. Malcolm (Austin, TX); Barnes, Zack (Austin, TX); Sawatari, Chie (Shizuoka, JP); Kondo, Tetsuo (Kukuoka, JP)

    2008-02-26T23:59:59.000Z

    The present invention includes a method, apparatus and system for nanofabrication in which one or more target molecules are identified for manipulation with an electron beam and the one or more target molecules are manipulated with the electron beam to produce new useful materials.

  17. Tunable transfer | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    July 29, 2013 Scientists gain first quantitative insights into electron transfer from minerals to microbes Scientists have gained the first quantitative insights into electron...

  18. Uncertain Power Flows and Transmission Planning

    E-Print Network [OSTI]

    capability and quantifying transmission revenues under uncertainty. Illustrative analyses demonstrated potential uses in transmission planning. Part I:Stochastic-Algebraic Evaluation of Available Transfer using a deterministic model for a given system state specified by given loads, generation, line

  19. Power Electronics for Distributed Energy Systems and Transmission and Distribution Applications: Assessing the Technical Needs for Utility Applications

    SciTech Connect (OSTI)

    Tolbert, L.M.

    2005-12-21T23:59:59.000Z

    Power electronics can provide utilities the ability to more effectively deliver power to their customers while providing increased reliability to the bulk power system. In general, power electronics is the process of using semiconductor switching devices to control and convert electrical power flow from one form to another to meet a specific need. These conversion techniques have revolutionized modern life by streamlining manufacturing processes, increasing product efficiencies, and increasing the quality of life by enhancing many modern conveniences such as computers, and they can help to improve the delivery of reliable power from utilities. This report summarizes the technical challenges associated with utilizing power electronics devices across the entire spectrum from applications to manufacturing and materials development, and it provides recommendations for research and development (R&D) needs for power electronics systems in which the U.S. Department of Energy (DOE) could make a substantial impact toward improving the reliability of the bulk power system.

  20. Vectorial electron transfer in spatially ordered arrays. Progress report, January 1991--December 1991

    SciTech Connect (OSTI)

    Fox, M.A.

    1992-01-01T23:59:59.000Z

    Progress has been made in four areas: the synthesis of new materials for directional electron; the preparation and characterization of anisotropic composites bearing organic and inorganic components; the elaboration of mechanisms of electrocatalysis; and the development of new methods for surface modification of metals and semiconductors.

  1. Comparison of Interfacial Electron Transfer through Carboxylate and Phosphonate Anchoring Groups

    E-Print Network [OSTI]

    in many molecule-based devices such as molecular electronics1 and dye-sensitized solar cells.2 Although of anchoring group on the efficiency of dye-sensitized solar cells (DSSCs) has also been investigated. So far) was found to be 30% less.8 In the latter cells, the sensitizer molecules wer

  2. Nonadiabatic Molecular Dynamics Study of Electron Transfer from Alizarin to the Hydrated Ti4+ Ion

    E-Print Network [OSTI]

    The dye-sensitized nanocrystalline solar cell, also known as the Gra¨tzel cell, is a promising alternative that forms the basis of the Gra¨tzel type solar cell. The experimental data and electronic structure to the more costly traditional solar cell.1-5 It employs organic or transition-metal- based chromophores

  3. Electron Transfer Reactivity Patterns at Chemically Modified Electrodes: Fundamentals and Application to the Optimization of Redox Recycling Amplification Systems

    SciTech Connect (OSTI)

    Adam Johan Bergren

    2006-05-01T23:59:59.000Z

    Electroanalytical chemistry is often utilized in chemical analysis and Fundamental studies. Important advances have been made in these areas since the advent of chemically modified electrodes: the coating of an electrode with a chemical film in order to impart desirable, and ideally, predictable properties. These procedures enable the exploitation of unique reactivity patterns. This dissertation presents studies that investigate novel reaction mechanisms at self-assembled monolayers on gold. In particular, a unique electrochemical current amplification scheme is detailed that relies on a selective electrode to enable a reactivity pattern that results in regeneration of the analyte (redox recycling). This regenerating reaction can occur up to 250 times for each analyte molecule, leading to a notable enhancement in the observed current. The requirements of electrode selectivity and the resulting amplification and detection limit improvements are described with respect to the heterogeneous and homogeneous electron transfer rates that characterize the system. These studies revealed that the heterogeneous electrolysis of the analyte should ideally be electrochemically reversible, while that for the regenerating agent should be held to a low level. Moreover, the homogeneous reaction that recycles the analyte should occur at a rapid rate. The physical selectivity mechanism is also detailed with respect to the properties of the electrode and redox probes utilized. It is shown that partitioning of the analyte into/onto the adlayer leads to the extraordinary selectivity of the alkanethiolate monolayer modified electrode. Collectively, these studies enable a thorough understanding of the complex electrode mechanism required for successful redox recycling amplification systems, Finally, in a separate (but related) study, the effect of the akyl chain length on the heterogeneous electron transfer behavior of solution-based redox probes is reported, where an odd-even oscillation (with respect to the number of methylene units in the alkyl chain) was observed. Characterization of the adlayers by infrared reflection spectroscopy, ellipsometry, and wetting revealed odd-even effects in the orientation of the terminal methyl group and hydrophobic character of the adlayers. Using these structural characterizations as a basis, several possible mechanisms that can account for the odd-even effect in the heterogeneous electron transfer rates of solution-based redox couples are discussed.

  4. Study of intermediates from transition metal excited-state electron-transfer reactions. Progress report, August 1, 1989--December 31, 1991

    SciTech Connect (OSTI)

    Hoffman, M.Z.

    1991-12-31T23:59:59.000Z

    During this period, conventional and fast-kinetics techniques of photochemistry, photophysics, radiation chemistry, and electrochemistry were used for the characterization of the intermediates that are involved in transition metal excited-state electron-transfer reactions. The intermediates of interest were the excited states of Ru(II) and Cr(III) photosensitizers, their reduced forms, and the species formed in the reactions of redox quenchers and electron-transfer agents. Of particular concern has been the back electron-transfer reaction between the geminate pair formed in the redox quenching of the photosensitizers, and the dependence of its rate on solution medium and temperature in competition with transformation and cage escape processes.

  5. Reorganization asymmetry of electron transfer in ferroelectric media and principles of artificial photosynthesis

    E-Print Network [OSTI]

    Dmitry V. Matyushov

    2006-03-24T23:59:59.000Z

    This study considers electronic transitions within donor-acceptor complexes dissolved in media with macroscopic polarization. The change of the polarizability of the donor-acceptor complex in the course of electronic transition couples to the reaction field of the polar environment and the electric field created by the macroscopic polarization. An analytical theory developed to describe this situation predicts a significant asymmetry of the reorganization energy between charge separation and charge recombination transitions. This result is proved by Monte Carlo simulations of a model polarizable diatomic dissolved in a ferroelectric fluid of soft dipolar spheres. The ratio of the reorganization energies for the forward and backward reactions up to a factor of 25 is obtained in the simulations. This result, as well as the effect of the macroscopic electric field, is discussed in application to the design of efficient photosynthetic devices.

  6. Electron Transfer within Self-Assembling Cyclic Tetramers Using Chlorophyll-Based Donor?Acceptor Building Blocks

    SciTech Connect (OSTI)

    Gunderson, Victoria L.; Smeigh, Amanda L.; Kim, Chul Hoon; Co, Dick T.; Wasielewski, Michael R. (NWU)

    2012-05-09T23:59:59.000Z

    The synthesis and photoinduced charge transfer properties of a series of Chl-based donor-acceptor triad building blocks that self-assemble into cyclic tetramers are reported. Chlorophyll a was converted into zinc methyl 3-ethylpyrochlorophyllide a (Chl) and then further modified at its 20-position to covalently attach a pyromellitimide (PI) acceptor bearing a pyridine ligand and one or two naphthalene-1,8:4,5-bis(dicarboximide) (NDI) secondary electron acceptors to give Chl-PI-NDI and Chl-PI-NDI2. The pyridine ligand within each ambident triad enables intermolecular Chl metal-ligand coordination in dry toluene, which results in the formation of cyclic tetramers in solution, as determined using small- and wide-angle X-ray scattering at a synchrotron source. Femtosecond and nanosecond transient absorption spectroscopy of the monomers in toluene-1% pyridine and the cyclic tetramers in toluene shows that the selective photoexcitation of Chl results in intramolecular electron transfer from 1*Chl to PI to form Chl+{lg_bullet}-PI-{lg_bullet}-NDI and Chl+{lg_bullet}-PI-{lg_bullet}-NDI2. This initial charge separation is followed by a rapid charge shift from PI-{lg_bullet} to NDI and subsequent charge recombination of Chl+{lg_bullet}-PI-NDI-{lg_bullet} and Chl+{lg_bullet}-PI-(NDI)NDI-{lg_bullet} on a 5-30 ns time scale. Charge recombination in the Chl-PI-NDI2 cyclic tetramer ({tau}CR = 30 {+-} 1 ns in toluene) is slower by a factor of 3 relative to the monomeric building blocks ({tau}CR = 10 {+-} 1 ns in toluene-1% pyridine). This indicates that the self-assembly of these building blocks into the cyclic tetramers alters their structures in a way that lengthens their charge separation lifetimes, which is an advantageous strategy for artificial photosynthetic systems.

  7. An analysis of crystal structure of selected rare earth fluorides by means of electron diffraction and transmission 

    E-Print Network [OSTI]

    Barr, Dennis Brannon

    1967-01-01T23:59:59.000Z

    many par- ticles that were several xnicrons in breadth. When bombarded with a beam of electrons intense enough to allow critical focusing of the microscope, these "larger" particles became very agitated. Since temperatures reached by specimens... in an electron micro- 6 scope xnay be as high as 200-300' C, the agitation of the particles could be related to a thermal motion. Accompanying this motion was what appeared to be a "melting" of the i'ormvar support film. When a thin carbon film was used...

  8. Watching Electrons Transfer from Metals to Insulators using Two Photon Photoemission

    SciTech Connect (OSTI)

    Johns, James E.

    2010-05-01T23:59:59.000Z

    Ultrafast angle-resolved two photon photoemission was used to study the dynamics and interfacial band structure of ultrathin films adsorbed onto Ag(111). Studies focused on the image potential state (IPS) in each system as a probe for measuring changes in electronic behavior in differing environments. The energetics and dynamics of the IPS at the toluene/Ag(111) interface are strongly dependent upon coverage. For a single monolayer, the first IPS is bound by 0.81 eV below the vacuum level and has a lifetime of 50 femtoseconds (fs). Further adsorption of toluene creates islands of toluene with an exposed wetting layer underneath. The IPS is then split into two peaks, one corresponding to the islands and one corresponding to the monolayer. The wetting layer IPS shows the same dynamics as the monolayer, while the lifetime of the islands increases exponentially with increasing thickness. Furthermore, the island IPS transitions from delocalized to localized within 500 fs, and electrons with larger parallel momenta decay much faster. Attempts were made using a stochastic model to extract the rates of localization and intraband cooling at differing momenta. In sexithiophene (6T) and dihexyl-sexithiophene (DH6T), the IPS was used as a probe to see if the nuclear motion of spectating side chains can interfere with molecular conduction. The energy and band mass of the IPS was measured for 6T and two geometries of DH6T on Ag(111). Electrons injected into the thicker coverages of DH6T grew exponentially heavier until they were completely localized by 230 fs, while those injected into 6T remained nearly free electron like. Based off of lifetime arguments and the density of defects, the most likely cause for the mass enhancement of the IPS in this system is small polaron formation caused by coupling of the electron to vibrations of the alkyl substituents. The energetic relaxation of the molecular adsorbate was also measured to be 20 meV/100 fs for the DH6T, and 0 meV/100 fs for the 6T. This relaxation is consistent with the localization of the charge creating a barrier for it moving from one lattice site to a neighboring one. Finally, the IPS was used to study the evolution of the surface band gap at the Mg/Ag(111) interface. The Mg(0001) surface band gap lies 1.6 eV below the Fermi level, and consequently shows no peak in the projected density of states for the IPS. A method for creating layer by layer growth of Mg on Ag(111) was determined using Auger Spectroscopy and low energy electron diffraction. By monitoring the decay of the intensity of the IPS versus coverage, it was determined that four layers of magnesium on Ag(111) is sufficient to completely eliminate the surface band gap

  9. Measurements of electron transfer from C0? and H? atoms to C²? and C?? ions

    E-Print Network [OSTI]

    Flowers-Cha?vez, Stephen

    1988-01-01T23:59:59.000Z

    was to attempt to more effectively drive out the C . C +, and C + ions. These ions were thought to contribute to the creation of Cz+. This was done by lowering the B field to 0. 52 T, lower than for the previous runs, and increasing the external driving signal... showing the split ring electrode, the external magnetic field, and the ion detection system. 2. Typical spectrum obtained from the analog plotter which was connected to the multichannel analyzer (MCA). 3. Shown is the electronic timing sequence used...

  10. The role of Shewanella oneidensis MR-1 outer surface structures in extracellular electron transfer

    SciTech Connect (OSTI)

    Bouhenni, Rachida; Vora, Gary J.; Biffinger, Justin C.; Shirodkar, Sheetal; Brockman, K. L.; Ray, Ricky; Wu, Peter; Johnson, Brandy J.; Biddle, E. M.; Marshall, Matthew J.; Fitzgerald, Lisa A.; Little, Brenda; Fredrickson, Jim K.; Beliaev, Alex S.; Ringeisen, Bradley R.; Saffarini, Daad

    2010-04-20T23:59:59.000Z

    Shewanella oneidensis is a facultative anaerobe that uses more than 14 different terminal electron acceptors for respiration. These include metal oxides and hydroxyoxides, and toxic metals such as uranium and chromium. Mutants deficient in metal reduction were isolated using the mariner transposon derivative, minihimar RB1. These included mutants with transposon insertions in the prepilin peptidase and type II secretion system genes. All mutants were deficient in Fe(III) and Mn(IV) reduction, and exhibited slow growth when DMSO was used as the electron acceptor. The genome sequence of S. oneidensis contains one prepilin peptidase gene, pilD. A similar prepilin peptidase that may function in the processing of type II secretion prepilins was not found. Single and multiple chromosomal deletions of four putative type IV pilin genes did not affect Fe(III) and Mn(IV) reduction. These results indicate that PilD in S. oneidensis is responsible for processing both type IV and type II secretion prepilin proteins. Type IV pili do not appear to be required for Fe(III) and Mn(IV) reduction.

  11. THE ROLE OF 4-HYDROXYPHENYLPYRUVATE DIOXYGENASE IN ENHANCEMENT OF SOLID-PHASE ELECTRON TRANSFER BY SHEWANELLA ONEIDENSIS MR-1

    SciTech Connect (OSTI)

    Turick, C; Amy Ekechukwu, A

    2007-06-01T23:59:59.000Z

    While mechanistic details of dissimilatory metal reduction are far from being understood, it is postulated that the electron transfer to solid metal oxides is mediated by outer membrane-associated c-type cytochromes and redox active electron shuttling compounds. This study focuses on the production of homogensitate in Shewanella oneidensis MR-1, an intermediate of tyrosine degradation pathway, which is a precursor of a redox cycling metabolite, pyomelanin. In this study, we determined that two enzymes involved in this pathway, 4-hydroxyphenylpyruvate dioxygenase (4HPPD) and homogentisate 1,2-dioxygenase are responsible for homogentisate production and oxidation, respectively. Inhibition of 4-HPPD activity with the specific inhibitor sulcotrione (2-(2-chloro-4-methane sulfonylbenzoyl)-1,3-cyclohexanedione), and deletion of melA, a gene encoding 4-HPPD, resulted in no pyomelanin production by S. oneidensis MR-1. Conversely, deletion of hmgA which encodes the putative homogentisate 1,2-dioxygenase, resulted in pyomelanin overproduction. The efficiency and rates, with which MR-1 reduces hydrous ferric oxide, were directly linked to the ability of mutant strains to produce pyomelanin. Electrochemical studies with whole cells demonstrated that pyomelanin substantially increases the formal potential (E{sup o}{prime}) of S. oneidensis MR-1. Based on this work, environmental production of pyomelanin likely contributes to an increased solid-phase metal reduction capacity in Shewanella oneidensis.

  12. Electronic couplings for molecular charge transfer: Benchmarking CDFT, FODFT, and FODFTB against high-level ab initio calculations

    SciTech Connect (OSTI)

    Kubas, Adam; Blumberger, Jochen, E-mail: j.blumberger@ucl.ac.uk [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom)] [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Hoffmann, Felix [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom) [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, Universitätsstr. 150, 44801 Bochum (Germany); Heck, Alexander; Elstner, Marcus [Institute of Physical Chemistry, Karlsruhe Institute of Technology, Fritz-Haber-Weg 6, 76131 Karlsruhe (Germany)] [Institute of Physical Chemistry, Karlsruhe Institute of Technology, Fritz-Haber-Weg 6, 76131 Karlsruhe (Germany); Oberhofer, Harald [Department of Chemistry, Technical University of Munich, Lichtenbergstr. 4, 85747 Garching (Germany)] [Department of Chemistry, Technical University of Munich, Lichtenbergstr. 4, 85747 Garching (Germany)

    2014-03-14T23:59:59.000Z

    We introduce a database (HAB11) of electronic coupling matrix elements (H{sub ab}) for electron transfer in 11 ?-conjugated organic homo-dimer cations. High-level ab inito calculations at the multireference configuration interaction MRCI+Q level of theory, n-electron valence state perturbation theory NEVPT2, and (spin-component scaled) approximate coupled cluster model (SCS)-CC2 are reported for this database to assess the performance of three DFT methods of decreasing computational cost, including constrained density functional theory (CDFT), fragment-orbital DFT (FODFT), and self-consistent charge density functional tight-binding (FODFTB). We find that the CDFT approach in combination with a modified PBE functional containing 50% Hartree-Fock exchange gives best results for absolute H{sub ab} values (mean relative unsigned error = 5.3%) and exponential distance decay constants ? (4.3%). CDFT in combination with pure PBE overestimates couplings by 38.7% due to a too diffuse excess charge distribution, whereas the economic FODFT and highly cost-effective FODFTB methods underestimate couplings by 37.6% and 42.4%, respectively, due to neglect of interaction between donor and acceptor. The errors are systematic, however, and can be significantly reduced by applying a uniform scaling factor for each method. Applications to dimers outside the database, specifically rotated thiophene dimers and larger acenes up to pentacene, suggests that the same scaling procedure significantly improves the FODFT and FODFTB results for larger ?-conjugated systems relevant to organic semiconductors and DNA.

  13. More stable hybrid organic solar cells deposited on amorphous Si electron transfer layer

    SciTech Connect (OSTI)

    Samiee, Mehran; Modtland, Brian; Dalal, Vikram L., E-mail: vdalal@iastate.edu [Iowa State University, Dept. of Electrical and Computer Engineering, Ames, Iowa 50011 (United States); Aidarkhanov, Damir [Nazarbayev University, Astana (Kazakhstan)

    2014-05-26T23:59:59.000Z

    We report on defect densities, performance, and stability of organic/inorganic hybrid solar cells produced using n-doped inorganic amorphous silicon-carbide layers as the electron transport layer (ETL). The organic material was poly-3-hexyl-thiophene (P3HT) and heterojunction was formed using phenyl-C{sub 71}-Butyric-Acid-Methyl Ester (PCBM). For comparison, inverted solar cells fabricated using Cs{sub 2}CO{sub 3} as ETL were fabricated. Defect densities and subgap quantum efficiency curves were found to be nearly identical for both types of cells. The cells were subjected to 2xsun illumination and it was found that the cells produced using doped a-Si as ETL were much more stable than the cells produced using Cs{sub 2}CO{sub 3}.

  14. Energetics of Electron Transfer at the Nanocrystalline Titanium Dioxide Semiconductor/ Aqueous Solution Interface: pH Invariance of the Metal-Based Formal Potential of a

    E-Print Network [OSTI]

    Energetics of Electron Transfer at the Nanocrystalline Titanium Dioxide Semiconductor/ Aqueous,4-(CH2PO3)-2,2-bipyridine)3 10-, bound to a nanocrystalline titanium dioxide film shows energy (ECB) of the underlying semiconductor electrode in response to the same environmental

  15. A technique for the observation of rapid solidification and annealing of powders in a transmission electron microscope

    SciTech Connect (OSTI)

    Kaufman, M.J.; Fraser, H.L.

    1983-01-01T23:59:59.000Z

    In the recent past, there has been considerable interest in the general area of rapid solidification processing (RSP). It is highly desirable to be able to make observations of not only the as-solidified microstructure of RSP materials, but also to determine its response to thermal excursions. This paper describes a new technique for in-situ studies of such processes where the electron beam in a TEM is used not only for imaging, diffraction and analytical purposes, but also as a local heating source. Thus, when making observations on submicron powders, produced by electrohydrodynamic atomization (EHD), it is possible to anneal and even melt particulate by focusing the electron beam in a controlled manner. The molten droplets can then be rapidly solidified by occluding the beam from the area of interest. A wide range of cooling rates may be achieved, the maximum being at least as rapid as that estimated for the EHD process, about 10/sup 5/ K/s (dependent on powder size). Two examples of the use of this technique are given. The first involves the melting, rapid solidification and subsequent heat treatment of an AL-4.5wt.%Cu alloy. The second is an example of how this technique may be used in studies of the crystallization of metallic glasses, in this case a Cu-45at.%Zr alloy.

  16. Nonadiabatic dynamics of electron transfer in solution: Explicit and implicit solvent treatments that include multiple relaxation time scales

    SciTech Connect (OSTI)

    Schwerdtfeger, Christine A.; Soudackov, Alexander V.; Hammes-Schiffer, Sharon, E-mail: shs3@illinois.edu [Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801 (United States)] [Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801 (United States)

    2014-01-21T23:59:59.000Z

    The development of efficient theoretical methods for describing electron transfer (ET) reactions in condensed phases is important for a variety of chemical and biological applications. Previously, dynamical dielectric continuum theory was used to derive Langevin equations for a single collective solvent coordinate describing ET in a polar solvent. In this theory, the parameters are directly related to the physical properties of the system and can be determined from experimental data or explicit molecular dynamics simulations. Herein, we combine these Langevin equations with surface hopping nonadiabatic dynamics methods to calculate the rate constants for thermal ET reactions in polar solvents for a wide range of electronic couplings and reaction free energies. Comparison of explicit and implicit solvent calculations illustrates that the mapping from explicit to implicit solvent models is valid even for solvents exhibiting complex relaxation behavior with multiple relaxation time scales and a short-time inertial response. The rate constants calculated for implicit solvent models with a single solvent relaxation time scale corresponding to water, acetonitrile, and methanol agree well with analytical theories in the Golden rule and solvent-controlled regimes, as well as in the intermediate regime. The implicit solvent models with two relaxation time scales are in qualitative agreement with the analytical theories but quantitatively overestimate the rate constants compared to these theories. Analysis of these simulations elucidates the importance of multiple relaxation time scales and the inertial component of the solvent response, as well as potential shortcomings of the analytical theories based on single time scale solvent relaxation models. This implicit solvent approach will enable the simulation of a wide range of ET reactions via the stochastic dynamics of a single collective solvent coordinate with parameters that are relevant to experimentally accessible systems.

  17. Author's Copy: J.B. Bancroft, A. Morrison, G. Lachapelle, Validation of GNSS under 500,000 V Direct Current (DC) transmission lines, Computers and Electronics in Agriculture, Volume 83, April 2012, Pages 58-67, ISSN 0168-1699, 10.1016/j.compag.2012.01.013

    E-Print Network [OSTI]

    Calgary, University of

    masking by the towers. Tests were conducted under a set of three transmission lines, two 500 kV DC lines Current (DC) transmission lines, Computers and Electronics in Agriculture, Volume 83, April 2012, Pages 58 Validation of GNSS under 500,000 Volt Direct Current (DC) Transmission Lines J.B. Bancroft*, A. Morrison

  18. Enrichment and Analysis of Nonenzymatically Glycated Peptides: Boronate Affinity Chromatography Coupled with Electron-Transfer Dissociation Mass Spectrometry

    SciTech Connect (OSTI)

    Zhang, Qibin; Tang, Ning; Brock, Jonathan W.; Mottaz, Heather M.; Ames, Jennifer M.; Baynes, John; Smith, Richard D.; Metz, Thomas O.

    2007-06-01T23:59:59.000Z

    Non-enzymatic glycation of peptides and proteins by D-glucose has important implications in the pathogenesis of diabetes mellitus, particularly in the development of diabetic complications. However, no effective high-throughput methods exist for identifying proteins containing this low abundance post-translational modification in bottom-up proteomic studies. In this report, phenylboronate affinity chromatography was used in a two-step enrichment scheme to selectively isolate first glycated proteins and then glycated, tryptic peptides from human serum glycated in vitro. Enriched peptides were subsequently analyzed by alternating electron transfer dissociation (ETD) and collision induced dissociation (CID) tandem mass spectrometry. It was observed that ETD fragmentation mode resulted in a significantly higher number of glycated peptide identifications (87.6% of all identified peptides) versus CID mode (17.0% of all identified peptides), when utilizing dual glycation enrichment on both the protein and peptide level. This study illustrates that phenylboronate affinity chromatography coupled with LC-MS/MS with ETD as the fragmentation mode is an efficient approach for analyses of glycated proteins and can have broad applications in studies of diabetes mellitus.

  19. Ultra-stable Molecule-Surface Architectures at Metal Oxides: Structure, Bonding, and Electron-transfer Processes

    SciTech Connect (OSTI)

    Hamers, Robert John

    2013-12-07T23:59:59.000Z

    Research funded by this project focused on the development of improved strategies for functionalization of metal oxides to enhance charge?transfer processes relevant to solar energy conversion. Initial studies included Fe2O3, WO3, TiO2, SnO2, and ZnO as model oxide systems; these systems were chosen due to differences in metal oxidation state and chemical bonding types in these oxides. Later studies focused largely on SnO2 and ZnO, as these materials show particularly promising surface chemistry, have high electron mobility, and can be readily grown in both spherical nanoparticles and as elongated nanorods. New molecules were synthesized that allowed the direct chemical assembly of novel nanoparticle ?dyadic? structures in which two different oxide materials are chemically joined, leading to an interface that enhances the separation of of charge upon illumination. We demonstrated that such junctions enhance photocatalytic efficiency using model organic compounds. A separate effort focused on novel approaches to linking dye molecules to SnO2 and ZnO as a way to enhance solar conversion efficiency. A novel type of surface binding through

  20. Electron Microscopy | Center for Functional Nanomaterials

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Capabilities Atomic-resolution imaging of internal materials structure with scanning transmission and transmission electron microscopy Spectroscopic characterization with...

  1. Transmission Services

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Return to Daylight Saving Time Posted: 2232015 Effective Date: 382015 This document provides the procedure for reserving and scheduling transmission that spans the time change...

  2. Theoretical Examination of Transfer Cavities in a Standing-wave Free-electron Laser Two-beam Accelerator

    E-Print Network [OSTI]

    Govil, R.

    2008-01-01T23:59:59.000Z

    Standing-Wave Free-Electron Laser Two-Beam Accelerator",the Standing-Wave Free-Electron Laser Two-Beam Accelerator",A.M. Sessler, "The Free-Electron Laser as a Power Source for

  3. Demonstration of an Electrochemical Liquid Cell for Operando Transmission Electron Microscopy Observation of the Lithiation/Delithiation Behavior of Si Nanowire Battery Anodes

    SciTech Connect (OSTI)

    Gu, Meng; Parent, Lucas R.; Mehdi, Beata L.; Unocic, Raymond R.; Mcdowell, Matthew T.; Sacci, Robert L.; Xu, Wu; Connell, Justin G.; Xu, Pinghong; Abellan Baeza, Patricia; Chen, Xilin; Zhang, Yaohui; Perea, Daniel E.; Evans, James E.; Lauhon, Lincoln; Zhang, Jiguang; Liu, Jun; Browning, Nigel D.; Cui, Yi; Arslan, Ilke; Wang, Chong M.

    2013-12-11T23:59:59.000Z

    Over the last few years, in-situ transmission electron microscopy (TEM) studies of lithium ion batteries using an open-cell configuration have helped us to gain fundamental insights into the structural and chemical evolution of the electrode materials in real time. In the standard open-cell configuration, the electrolyte is either solid lithium oxide or an ionic liquid, which is point-contacted with the electrode. This cell design is inherently different from a real battery, where liquid electrolyte forms conformal contact with electrode materials. The knowledge learnt from open cells can deviate significantly from the real battery, calling for operando TEM technique with conformal liquid electrolyte contact. In this paper, we developed an operando TEM electrochemical liquid cell to meet this need, providing the configuration of a real battery and in a relevant liquid electrolyte. To demonstrate this novel technique, we studied the lithiation/delithiation behavior of single Si nanowires. Some of lithiation/delithation behaviors of Si obtained using the liquid-cell are consistent with the results from the open-cell studies. However, we also discovered new insights different from the open cell configuration - the dynamics of the electrolyte and, potentially, a future quantitative characterization of the SEI layer formation and structural and chemical evolution.

  4. In-situ high resolution transmission electron microscopy observation of silicon nanocrystal nucleation in a SiO{sub 2} bilayered matrix

    SciTech Connect (OSTI)

    Yang, T. C.-J., E-mail: terry.yang@unsw.edu.au; Wu, L.; Lin, Z.; Jia, X.; Puthen-Veettil, B.; Zhang, T.; Conibeer, G.; Perez-Wurfl, I. [School of Photovoltaic and Renewable Engineering, University of New South Wales, Sydney, New South Wales 2052 (Australia); Kauffmann, Y.; Rothschild, A. [Department of Materials Science and Engineering, Technion – Israel Institute of Technology, Technion City, Haifa 32000 (Israel)

    2014-08-04T23:59:59.000Z

    Solid-state nucleation of Si nanocrystals in a SiO{sub 2} bilayered matrix was observed at temperatures as low as 450?°C. This was achieved by aberration corrected high-resolution transmission electron microscopy (HRTEM) with real-time in-situ heating up to 600?°C. This technique is a valuable characterization tool especially with the recent interest in Si nanostructures for light emitting devices, non-volatile memories, and third-generation photovoltaics which all typically require a heating step in their fabrication. The control of size, shape, and distribution of the Si nanocrystals are critical for these applications. This experimental study involves in-situ observation of the nucleation of Si nanocrystals in a SiO{sub 2} bilayered matrix fabricated through radio frequency co-sputtering. The results show that the shapes of Si nanocrystals in amorphous SiO{sub 2} bilayered matrices are irregular and not spherical, in contrast to many claims in the literature. Furthermore, the Si nanocrystals are well confined within their layers by the amorphous SiO{sub 2}. This study demonstrates the potential of in-situ HRTEM as a tool to observe the real time nucleation of Si nanocrystals in a SiO{sub 2} bilayered matrix. Furthermore, ideas for improvements on this in-situ heating HRTEM technique are discussed.

  5. In situ investigation of explosive crystallization in a-Ge: Experimental determination of the interface response function using dynamic transmission electron microscopy

    SciTech Connect (OSTI)

    Nikolova, Liliya; MacLeod, Jennifer M.; Ibrahim, Heide [Centre Énergie, Matériaux, Télécommunications, Institut National de la Recherche Scientifique, 1650 Lionel Boulet boulevard, Varennes, Quebec J3X 1S2 (Canada); Stern, Mark J.; Siwick, Bradley J., E-mail: rosei@emt.inrs.ca, E-mail: lagrange2@llnl.gov, E-mail: bradley.siwick@mcgill.ca [Center for the Physics of Materials, Departments of Physics and Chemistry, McGill University, 801 Sherbrooke St. W., Montreal, Quebec H3A 2K6 (Canada); Reed, Bryan W.; Campbell, Geoffrey H.; LaGrange, Thomas, E-mail: rosei@emt.inrs.ca, E-mail: lagrange2@llnl.gov, E-mail: bradley.siwick@mcgill.ca [Condensed Matter and Materials Division, Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551-0808 (United States); Rosei, Federico, E-mail: rosei@emt.inrs.ca, E-mail: lagrange2@llnl.gov, E-mail: bradley.siwick@mcgill.ca [Centre Énergie, Matériaux, Télécommunications, Institut National de la Recherche Scientifique, 1650 Lionel Boulet boulevard, Varennes, Quebec J3X 1S2 (Canada); Centre for Self-Assembled Chemical Structures, McGill University, 801 Sherbrooke St. W., Montreal, Quebec H3A 2K6 (Canada)

    2014-09-07T23:59:59.000Z

    The crystallization of amorphous semiconductors is a strongly exothermic process. Once initiated the release of latent heat can be sufficient to drive a self-sustaining crystallization front through the material in a manner that has been described as explosive. Here, we perform a quantitative in situ study of explosive crystallization in amorphous germanium using dynamic transmission electron microscopy. Direct observations of the speed of the explosive crystallization front as it evolves along a laser-imprinted temperature gradient are used to experimentally determine the complete interface response function (i.e., the temperature-dependent front propagation speed) for this process, which reaches a peak of 16?m/s. Fitting to the Frenkel-Wilson kinetic law demonstrates that the diffusivity of the material locally/immediately in advance of the explosive crystallization front is inconsistent with those of a liquid phase. This result suggests a modification to the liquid-mediated mechanism commonly used to describe this process that replaces the phase change at the leading amorphous-liquid interface with a change in bonding character (from covalent to metallic) occurring in the hot amorphous material.

  6. Study of intermediates from transition metal excited-state electron-transfer reactions. Progress report, April 1, 1984-March 31, 1985. [EDTA-radicals

    SciTech Connect (OSTI)

    Hoffman, M.Z.

    1985-03-31T23:59:59.000Z

    Excited-state inter- and intramolecular electron-transfer reactions lie at the heart of most photochemical solar energy conversion schemes. Our research, which utilizes the techniques of continuous and pulsed photolysis and radiolysis, has focused on three general aspects of these reactions involving transition metal coordination complexes and electron donor-acceptor complexes: (1) the effect of solution medium on the properties and quenching of the excited states; (2) the control of the quantum yield of formation of redox products; and (3) the mechanisms by which reduced species interact with water to yield H/sub 2/ homogeneously and heterogeneously. Research activities are summarized for the following: (1) reaction of methyl viologen with EDTA-radicals; (2) solution medium control of photoredox yields; (3) photochemistry of methyl viologen charge-transfer complexes; (4) thermal reduction of methyl viologen in alkaline solution; (5) formation of dihydrogen from reduced methyl viologen; and (6) photophysics of Cr(III)-polypyridyl complexes.

  7. Photo-induced water oxidation at the aqueous GaN (101?0) interface: Deprotonation kinetics of the first proton-coupled electron-transfer step

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Ertem, Mehmed Z. [Brookhaven National Lab. (BNL), Upton, NY (United States); Yale Univ., New Haven, CT (United States); Kharche, Neerav [Brookhaven National Lab. (BNL), Upton, NY (United States); Batista, Victor S. [Yale Univ., New Haven, CT (United States); Hybertsen, Mark S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Tully, John C. [Yale Univ., New Haven, CT (United States); Muckerman, James T. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-04-03T23:59:59.000Z

    Photoeclectrochemical water splitting plays a key role in a promising path to the carbon-neutral generation of solar fuels. Wurzite GaN and its alloys (e.g., GaN/ZnO and InGaN) are demonstrated photocatalysts for water oxidation, and they can drive the overall water splitting reaction when coupled with co-catalysts for proton reduction. In the present work, we investigate the water oxidation mechanism on the prototypical GaN (101?0) surface using a combined ab initio molecular dynamics and molecular cluster model approach taking into account the role of water dissociation and hydrogen bonding within the first solvation shell of the hydroxylated surface. The investigation of free-energy changes for the four proton-coupled electron-transfer (PCET) steps of the water oxidation mechanism shows that the first PCET step for the conversion of –Ga-OH to –Ga-O?? requires the highest energy input. We further examine the sequential PCETs, with the proton transfer (PT) following the electron transfer (ET), and find that photo-generated holes localize on surface –NH sites is thermodynamically more favorable than –OH sites. However, proton transfer from –OH sites with subsequent localization of holes on oxygen atoms is kinetically favored owing to hydrogen bonding interactions at the GaN (101?0)–water interface. We find that the deprotonation of surface –OH sites is the limiting factor for the generation of reactive oxyl radical ion intermediates and consequently for water oxidation.

  8. Silver diffusion bonding and layer transfer of lithium niobate to silicon Kenneth Diest,a

    E-Print Network [OSTI]

    Atwater, Harry

    Silver diffusion bonding and layer transfer of lithium niobate to silicon Kenneth Diest,a Melissa J July 2008; accepted 8 August 2008; published online 5 September 2008 A diffusion bonding method has, and upon heating, a diffusion bond was formed. Transmission electron microscopy confirms the interface

  9. Calculations of Nonlinear Wave-Packet Interferometry Signals in the Pump-Probe Limit as Tests for Vibrational Control over Electronic Excitation Transfer

    E-Print Network [OSTI]

    Jason D. Biggs; Jeffrey A. Cina

    2009-10-12T23:59:59.000Z

    The preceding paper describes a strategy for externally influencing the course of short-time electronic excitation transfer (EET) in molecular dimers and observing the process by nonlinear wave-packet interferometry (nl-WPI). Within a sample of isotropically oriented dimers having a specified internal geometry, a vibrational mode internal to the acceptor chromophore can be preferentially driven by electronically nonresonant impulsive stimulated Raman (or resonant infrared) excitation with a short polarized control pulse. A subsequent electronically resonant polarized pump then preferentially excites the donor, and EET ensues. Here we test both the control strategy and its spectroscopic investigation-with some sacrifice of amplitude-level detail-by calculating the pump-probe difference signal. That signal is the limiting case of the control-influenced nl-WPI signal in which the two pulses in the pump pulse-pair coincide, as do the two pulses in the probe pulse-pair. We present calculated pump-probe difference signals for (1) a model excitation-transfer complex in which two equal-energy monomers each support one moderately Franck-Condon active intramolecular vibration; (2) a simplified model of the covalent dimer dithia-anthracenophane, representing its EET dynamics following selective impulsive excitation of the weakly Franck-Condon active anthracene vibration at 385 cm-1; and (3) a model complex featuring moderate electronic-vibrational coupling in which the site energy of the acceptor chromophore is lower than that of the donor.

  10. Transmission Services J7000

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Transmission Business Unit - J7300 CRSP - DSW - RMR Open Access Transmission Tariff Management Transmission Service Requests Interconnection Requests OASIS...

  11. A parametric study of shock jump chemistry, electron temperature, and radiative heat transfer models in hypersonic flows 

    E-Print Network [OSTI]

    Greendyke, Robert Brian

    1988-01-01T23:59:59.000Z

    will examine the radiance model and various step models in order to determine their appropriateness to the flight regime of the AOTV. The final area to be investigated will be the effect of nonequilibrium corrections on the radiative heat transfer models... of T and e T will be valid as long as there is a reasonable amount vNs of nitrogen molecules in the flow. Radiative Heat Transfer Models For this study, four radiative heat transfer models were examined. One of these models is an optically thin radiance...

  12. Direct electron detection in transmission electron microscopy

    E-Print Network [OSTI]

    Jin, Liang

    2009-01-01T23:59:59.000Z

    Duttweiler, J. Bouwer, S. Peltier, M. Ellisman, P. Denes, F.J. C. Bouwer, S. T. Peltier, M. Ellisman and N. -H. Xuong (J. C. Bouwer, S. T. Peltier, M. H. Ellisman and N. H.

  13. Direct electron detection in transmission electron microscopy

    E-Print Network [OSTI]

    Jin, Liang

    2009-01-01T23:59:59.000Z

    overlay on the photo showed how the sensor chip was aligned40. Photo of the EM5 carrier board with mounted sensor40. Photo of the EM5 carrier board with mounted sensor chip.

  14. Direct imaging of crystal structure and defects in metastable Ge{sub 2}Sb{sub 2}Te{sub 5} by quantitative aberration-corrected scanning transmission electron microscopy

    SciTech Connect (OSTI)

    Ross, Ulrich; Lotnyk, Andriy, E-mail: andriy.lotnyk@iom-leipzig.de; Thelander, Erik; Rauschenbach, Bernd [Leibniz Institute of Surface Modification, Permoserstr. 15, D-04318 Leipzig (Germany)

    2014-03-24T23:59:59.000Z

    Knowledge about the atomic structure and vacancy distribution in phase change materials is of foremost importance in order to understand the underlying mechanism of fast reversible phase transformation. In this Letter, by combining state-of-the-art aberration-corrected scanning transmission electron microscopy with image simulations, we are able to map the local atomic structure and composition of a textured metastable Ge{sub 2}Sb{sub 2}Te{sub 5} thin film deposited by pulsed laser deposition with excellent spatial resolution. The atomic-resolution scanning transmission electron microscopy investigations display the heterogeneous defect structure of the Ge{sub 2}Sb{sub 2}Te{sub 5} phase. The obtained results are discussed. Highly oriented Ge{sub 2}Sb{sub 2}Te{sub 5} thin films appear to be a promising approach for further atomic-resolution investigations of the phase change behavior of this material class.

  15. An improved speech transmission index for intelligibility prediction Belinda Schwerin

    E-Print Network [OSTI]

    transmission index; Modulation transfer function; Speech enhancement; Objective evaluation; Speech intelligibility; Short-time modulation spectrum 1. Introduction The enhancement of speech corrupted by noise hasAn improved speech transmission index for intelligibility prediction Belinda Schwerin , Kuldip

  16. Application of High-Angle Annular Dark Field Scanning Transmission

    E-Print Network [OSTI]

    Utsunomiya, Satoshi

    Transmission Electron Microscopy-Energy Dispersive X-ray Spectrometry, and Energy-Filtered Transmission field scanning transmission electron microscopy (HAADF-STEM), STEM-energy-dispersive X-ray spectrometry). Techniquesthatareusefulinanalyzingultrafineatmospheric particles, such as STEM, EELS (electron energy loss spec- trometry), AFM, and mass spectrometry

  17. Electron transfer through a lipid-bilayer-membrane-aqueous-solution interface and kinetics of the oxidation of viologen radicals in homogeneous and vesicular systems

    SciTech Connect (OSTI)

    Shafirovich, V.Ya.; Levin, P.P.; Khannanov, N.K.; Kuz'min, V.A.

    1986-10-10T23:59:59.000Z

    The purpose of the present work was to study the influence of the nature of the oxidizing agent on the rate constant of the oxidation of viologen radicals in homogeneous and vesicular systems by water-soluble oxidizing agents. In this work the authors used the following water-soluble viologens: methyl viologen, sulfoethyl viologen, trimethylaminopropyl viologen, and octadecyl viologen, which is soluble only in a lipid bilayer. The rate constant for the oxidation of a viologen radical cation in a lipid bilayer by electron acceptors in the aqueous phase, in contrast to the homogeneous reaction, is lower than the rate constant of the diffusion-controlled reaction. The rate of electron transfer on the interface is determined by the interaction of the reactants with the lipid bilayer. The rate constant for electron transfer from a viologen radical cation near the inner surface of a lipid bilayer to viologen near the outer surface with the formation of a radical which is available for oxidation in the external aqueous phase has been determined and has been found to be independent of the nature of the oxidizing agent.

  18. Photo-induced water oxidation at the aqueous GaN (101?0) interface: Deprotonation kinetics of the first proton-coupled electron-transfer step

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Ertem, Mehmed Z.; Kharche, Neerav; Batista, Victor S.; Hybertsen, Mark S.; Tully, John C.; Muckerman, James T.

    2015-04-03T23:59:59.000Z

    Photoeclectrochemical water splitting plays a key role in a promising path to the carbon-neutral generation of solar fuels. Wurzite GaN and its alloys (e.g., GaN/ZnO and InGaN) are demonstrated photocatalysts for water oxidation, and they can drive the overall water splitting reaction when coupled with co-catalysts for proton reduction. In the present work, we investigate the water oxidation mechanism on the prototypical GaN (101?0) surface using a combined ab initio molecular dynamics and molecular cluster model approach taking into account the role of water dissociation and hydrogen bonding within the first solvation shell of the hydroxylated surface. The investigation ofmore »free-energy changes for the four proton-coupled electron-transfer (PCET) steps of the water oxidation mechanism shows that the first PCET step for the conversion of –Ga-OH to –Ga-O?? requires the highest energy input. We further examine the sequential PCETs, with the proton transfer (PT) following the electron transfer (ET), and find that photo-generated holes localize on surface –NH sites is thermodynamically more favorable than –OH sites. However, proton transfer from –OH sites with subsequent localization of holes on oxygen atoms is kinetically favored owing to hydrogen bonding interactions at the GaN (101?0)–water interface. We find that the deprotonation of surface –OH sites is the limiting factor for the generation of reactive oxyl radical ion intermediates and consequently for water oxidation.« less

  19. The number of multimedia transmissions over the existing network infrastructure is continually increasing.

    E-Print Network [OSTI]

    ABSTRACT The number of multimedia transmissions over the existing network infrastructure and hence their play- out. We propose a novel feedback controlled multimedia transmission scheme in order are being transferred between remotely situated computers. Multimedia transmissions, especially of a real

  20. An examination of electronic file transfer between host and microcomputers for the AMPMODNET/AIMNET (Army Material Plan Modernization Network/Acquisition Information Management Network) classified network environment

    SciTech Connect (OSTI)

    Hake, K.A.

    1990-11-01T23:59:59.000Z

    This report presents the results of investigation and testing conducted by Oak Ridge National Laboratory (ORNL) for the Project Manager -- Acquisition Information Management (PM-AIM), and the United States Army Materiel Command Headquarters (HQ-AMC). It concerns the establishment of file transfer capabilities on the Army Materiel Plan Modernization (AMPMOD) classified computer system. The discussion provides a general context for micro-to-mainframe connectivity and focuses specifically upon two possible solutions for file transfer capabilities. The second section of this report contains a statement of the problem to be examined, a brief description of the institutional setting of the investigation, and a concise declaration of purpose. The third section lays a conceptual foundation for micro-to-mainframe connectivity and provides a more detailed description of the AMPMOD computing environment. It gives emphasis to the generalized International Business Machines, Inc. (IBM) standard of connectivity because of the predominance of this vendor in the AMPMOD computing environment. The fourth section discusses two test cases as possible solutions for file transfer. The first solution used is the IBM 3270 Control Program telecommunications and terminal emulation software. A version of this software was available on all the IBM Tempest Personal Computer 3s. The second solution used is Distributed Office Support System host electronic mail software with Personal Services/Personal Computer microcomputer e-mail software running with IBM 3270 Workstation Program for terminal emulation. Test conditions and results are presented for both test cases. The fifth section provides a summary of findings for the two possible solutions tested for AMPMOD file transfer. The report concludes with observations on current AMPMOD understanding of file transfer and includes recommendations for future consideration by the sponsor.

  1. Energy transfer and 1.54 m emission in amorphous silicon nitride films S. O. Kucheyev,2

    E-Print Network [OSTI]

    spectrometry RBS and high-resolution transmission electron microscopy HRTEM to quantify the amount of Si, NEnergy transfer and 1.54 m emission in amorphous silicon nitride films S. Yerci,1 R. Li,1 S. O a broad energy spectrum and attributed to disorder-induced localized transitions in amorphous Er

  2. Comparing ultrafast surface and bulk heating using time-resolved electron diffraction

    SciTech Connect (OSTI)

    Streubühr, C.; Kalus, A.; Zhou, P., E-mail: ping.zhou@uni-due.de; Kammler, M.; Linde, D. von der [Faculty of Physics, University of Duisburg-Essen, Duisburg 47057 (Germany); Ligges, M.; Hanisch-Blicharski, A.; Bovensiepen, U.; Horn-von Hoegen, M. [Faculty of Physics, University of Duisburg-Essen, Duisburg 47057 (Germany); CENIDE, Centre for Nano Integration Duisburg Essen, Duisburg 47057 (Germany)

    2014-04-21T23:59:59.000Z

    From measurements of the transient Debye-Waller effect in Bismuth, we determine the buildup time of the random atomic motion resulting from the electronic relaxation after short pulse laser excitation. The surface sensitive reflection high energy electron diffraction and transmission electron diffraction yield a time constant of about 12 ps and 3 ps, respectively. The different energy transfer rates indicate relatively weak coupling between bulk and surface vibrational modes.

  3. Photodegradation of oligomeric polyesters containing anthraquinone and 1,2-diamine units. Single electron transfer induced cation radical bond cleavage in the solid state

    SciTech Connect (OSTI)

    Leon, J.W.; Whitten, D.G. (Univ. of Rochester, NY (United States))

    1995-03-01T23:59:59.000Z

    Oligomeric polyesters containing light-absorbing anthraquinone electron acceptor chromophores and fragmentable 1,2-diamine donors have been synthesized. Irradiation with [lambda] [ge] 340 nm in solution or as solid films results in photooxidative C-C bond cleavage of the 1,2-diamine units yielding essentially the same products in either case. The solid state photodegradation reaction was monitored using size exclusion chromatography and was found to be substantially less efficient than the corresponding solution reaction. This is attributed to an inefficient forward electron transfer step and the possibility of an induced reversibility of the fragmentation. The efficiency of photodegradation is suggested to be dependent on the donor/acceptor orientations in the solid state. 49 refs., 11 figs., 1 tab.

  4. Transmission INTRODUCTION

    E-Print Network [OSTI]

    , to a significant degree, on a well-functioning wholesale power market. The transmission system is integral the consequences of a poorly designed wholesale power market, and the Council does not want to see those Regulatory Commission began taking actions to further facilitate competition in wholesale power supply. Today

  5. Laser-Energy Transfer and Enhancement of Plasma Waves and Electron Beams by Interfering High-Intensity Laser Pulses

    E-Print Network [OSTI]

    Umstadter, Donald

    603, Beijing 100080, People's Republic of China (Received 14 February 2003; published 25 November 2003 the higher-power to the lower-power pulse, increasing the amplitude of the plasma wave propagating- sible for the energy transfer in this case differs from that studied in previous long-pulse and low-power

  6. Photoinduced electron transfer in donor-acceptor aryl dyads based on N,N,N`,N`-tetramethyl-p-phenylenedimine as the donor

    SciTech Connect (OSTI)

    Fossum, R.D.; Fox, M.A. [Univ. of Texas, Austin, TX (United States)] [Univ. of Texas, Austin, TX (United States); Gelormini, A.M.; Pearson, A.J. [Case Western Reserve Univ., Cleveland, OH (United States)] [Case Western Reserve Univ., Cleveland, OH (United States)

    1997-04-03T23:59:59.000Z

    The solution-phase photophysics of several electron transfer donor-donor-acceptor assemblies (2 and 3) incorporating N,N,N`,N`-tetramethyl-p-phenylenediamine (TMPD) derivatized with piperazyl, piperidyl, morpholinyl, and prolinyl groups in the 1- and 4-positions as donors and N,N-dimethyl-4-nitroaniline, anthraquinone, 3,5-dinitrobenzene, and 2,4-dinitrobenzene as acceptors are described. In measurements of the model compounds 1 incorporating only the donor moieties, flash photolysis generated the radical cation and triplet species of TMPD as evidenced by the superposition of their transient absorption spectra. Lifetime measurements reveal, as well, a delayed fluorescence derived from triplet-triplet annihilation. In 2 and 3, electron transfer from the lowest excited singlet state of TMPD to the various acceptors was established by the following: (1) steady-state emission measurements where the fluorescence of TMPD was drastically quenched by the acceptor, (2) the transient absorption spectra of the radical cation and radical anion of the donor and acceptor, and (3) a single-exponential decay profile in 2 and 3, superseding the biexponential decay observed in the model donor. 37 refs., 3 figs., 2 tabs.

  7. Ab initio calculation of proton-coupled electron transfer rates using the external-potential representation: A ubiquinol complex in solution

    SciTech Connect (OSTI)

    Yamamoto, Takeshi; Kato, Shigeki [Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502 (Japan)

    2007-06-14T23:59:59.000Z

    In quantum-mechanical/molecular-mechanical (QM/MM) treatment of chemical reactions in condensed phases, one solves the electronic Schroedinger equation for the solute (or an active site) under the electrostatic field from the environment. This Schroedinger equation depends parametrically on the solute nuclear coordinates R and the external electrostatic potential V. This fact suggests that one may use R and V as natural collective coordinates for describing the entire system, where V plays the role of collective solvent variables. In this paper such an (R,V) representation of the QM/MM canonical ensemble is described, with particular focus on how to treat charge transfer processes in this representation. As an example, the above method is applied to the proton-coupled electron transfer of a ubiquinol analog with phenoxyl radical in acetonitrile solvent. Ab initio free-energy surfaces are calculated as functions of R and V using the reference interaction site model self-consistent field method, the equilibrium points and the minimum free-energy crossing point are located in the (R,V) space, and then the kinetic isotope effects (KIEs) are evaluated approximately. The results suggest that a stiffer proton potential at the transition state may be responsible for unusual KIEs observed experimentally for related systems.

  8. Electron energy loss spectroscopy of gold nanoparticles on graphene

    SciTech Connect (OSTI)

    DeJarnette, Drew [Microelectronics and Photonics Graduate Program, University of Arkansas, Fayetteville, Arkansas 72701 (United States); Roper, D. Keith, E-mail: dkroper@uark.edu [Microelectronics and Photonics Graduate Program, University of Arkansas, Fayetteville, Arkansas 72701 (United States); Department of Chemical Engineering, University of Arkansas, Fayetteville, Arkansas 72701 (United States)

    2014-08-07T23:59:59.000Z

    Plasmon excitation decay by absorption, scattering, and hot electron transfer has been distinguished from effects induced by incident photons for gold nanoparticles on graphene monolayer using electron energy loss spectroscopy (EELS). Gold nano-ellipses were evaporated onto lithographed graphene, which was transferred onto a silicon nitride transmission electron microscopy grid. Plasmon decay from lithographed nanoparticles measured with EELS was compared in the absence and presence of the graphene monolayer. Measured decay values compared favorably with estimated radiative and non-radiative contributions to decay in the absence of graphene. Graphene significantly enhanced low-energy plasmon decay, increasing mode width 38%, but did not affect higher energy plasmon or dark mode decay. This decay beyond expected radiative and non-radiative mechanisms was attributed to hot electron transfer, and had quantum efficiency of 20%, consistent with previous reports.

  9. Transmission Investment: A Primer

    SciTech Connect (OSTI)

    McGarvey, Joe

    2006-10-15T23:59:59.000Z

    This primer highlights recent trends in transmission investment, summarizes the division of jurisdictional authority over transmission, and presents four alternative models for transmission ownership. (author)

  10. Electron-Transfer from H-2 and Ar to Stored Multiply Charged Argon Ions Produced by Synchrotron Radiation 

    E-Print Network [OSTI]

    Kravis, S. D.; Church, David A.; Johnson, B. M.; Meron, M.; Jones, K. W.; Levin, J. C.; Sellin, I. A.; Azuma, Y.; Berrahmansour, N.; Berry, H. G.; Druetta, M.

    1992-01-01T23:59:59.000Z

    -shell photoionization of Ar atoms, using broadband synchrotron x-ray radiation. K-electron removal resulted in vacancy cascading, yielding a distribution of argon-ion charge states peaked near Ar4+. The stored ion gas had an initial temperature near 480 K. The basic...

  11. Electron-Transfer from H-2 and Ar to Stored Multiply Charged Argon Ions Produced by Synchrotron Radiation

    E-Print Network [OSTI]

    Kravis, S. D.; Church, David A.; Johnson, B. M.; Meron, M.; Jones, K. W.; Levin, J. C.; Sellin, I. A.; Azuma, Y.; Berrahmansour, N.; Berry, H. G.; Druetta, M.

    1992-01-01T23:59:59.000Z

    -shell photoionization of Ar atoms, using broadband synchrotron x-ray radiation. K-electron removal resulted in vacancy cascading, yielding a distribution of argon-ion charge states peaked near Ar4+. The stored ion gas had an initial temperature near 480 K. The basic...

  12. Final Report Navajo Transmission Project (NTP)

    SciTech Connect (OSTI)

    Bennie Hoisington; Steven Begay

    2006-09-14T23:59:59.000Z

    The Diné Power Authority is developing the Navajo Transmission Project (NTP) to relieve the constraints on the transmission of electricity west of the Four Corners area and to improve the operation flexibility and reliability of the extra-high-voltage transmission system in the region. The NTP creates the wholesale transmission capacity for more economical power transfers, sales, and purchases in the region. It will facilitate the development of Navajo energy resources, improve economic conditions on the Navajo Nation as well as allow DPA to participate in the western electrical utility industry.

  13. Complex formation between anthraquinone-2,6-disulfonate and a neutral zinc porphyrin. Effects of CTAB micelles on complex stability and photoinduced electron transfer

    SciTech Connect (OSTI)

    Degani, Y.; Willner, I.

    1985-12-19T23:59:59.000Z

    Zinc(II) meso-tetrakis(1-(3-sulfonatopropyl)-4-pyridino), Zn-TPSPyP/sup 0/, forms a complex with anthraquinone-2,6-disulfonate, AQS/sub 2//sup 2 -/. The porphyrin is statically quenched by the quinone acceptor in the complex structure. In the presence of CTAB micelles the complex is separated and AQS/sub 2//sup 2 -/ is bound to the micelles. The excited sensitizer decays to a long-lived triplet state (0.5 ms) and induces the reduction of AQS/sub 2//sup 2 -/. The micelles also function in the charge separation of the electron-transfer products. 22 references, 6 figures, 1 table.

  14. The interaction of flow, heat transfer, and free interfaces in an electron-beam vaporization system for metals

    SciTech Connect (OSTI)

    Westerberg, K.W. [Aspen Technology, Inc., Cambridge, MA (United States); McClelland, M.A. [Lawrence Livermore National Lab., CA (United States); Finlayson, B.A. [Univ. of Washington, Seattle, WA (United States)

    1994-11-01T23:59:59.000Z

    A numerical analysis is made of the liquid flow and energy transport in a system to vaporize metals. The energy from an electron beam heats metal confined in a water-cooled crucible. Metal vaporizes from a hot pool of circulating liquid which is surrounded by a shell of its own solid. Flow in the pool is strongly driven by temperature-induced buoyancy and capillary forces and is located in the transition region between laminar and turbulent flow. At high vaporization rates, the thrust of the departing vapor forms a trench at the beam impact site. A modified finite element method is used to calculate the flow and temperature fields coupled with the interface locations. The mesh is structured with spines that stretch and pivot as the interfaces move. The discretized equations are arranged in an {open_quotes}arrow{close_quotes} matrix and solved using the Newton-Raphson method. The electron-beam power and width are varied for cases involving the high-rate vaporization of aluminum. Attention is focused on the interaction of vaporization, liquid flow, and heat transport in the trench area.

  15. Optical characterization of free electron concentration in heteroepitaxial InN layers using Fourier transform infrared spectroscopy and a 2 Multiplication-Sign 2 transfer-matrix algebra

    SciTech Connect (OSTI)

    Katsidis, C. C. [Department of Materials Science and Technology, University of Crete, P.O. Box 2208, 71003 Heraklion-Crete (Greece); Ajagunna, A. O.; Georgakilas, A. [Microelectronics Research Group, IESL, FORTH, P.O. Box 1385, 71110 Heraklion-Crete (Greece); Physics Department, University of Crete, P.O. Box 2208, 71003 Heraklion-Crete (Greece)

    2013-02-21T23:59:59.000Z

    Fourier Transform Infrared (FTIR) reflectance spectroscopy has been implemented as a non-destructive, non-invasive, tool for the optical characterization of a set of c-plane InN single heteroepitaxial layers spanning a wide range of thicknesses (30-2000 nm). The c-plane (0001) InN epilayers were grown by plasma-assisted molecular beam epitaxy (PAMBE) on GaN(0001) buffer layers which had been grown on Al{sub 2}O{sub 3}(0001) substrates. It is shown that for arbitrary multilayers with homogeneous anisotropic layers having their principal axes coincident with the laboratory coordinates, a 2 Multiplication-Sign 2 matrix algebra based on a general transfer-matrix method (GTMM) is adequate to interpret their optical response. Analysis of optical reflectance in the far and mid infrared spectral range has been found capable to discriminate between the bulk, the surface and interface contributions of free carriers in the InN epilayers revealing the existence of electron accumulation layers with carrier concentrations in mid 10{sup 19} cm{sup -3} at both the InN surface and the InN/GaN interface. The spectra could be fitted with a three-layer model, determining the different electron concentration and mobility values of the bulk and of the surface and the interface electron accumulation layers in the InN films. The variation of these values with increasing InN thickness could be also sensitively detected by the optical measurements. The comparison between the optically determined drift mobility and the Hall mobility of the thickest sample reveals a value of r{sub H} = 1.49 for the Hall factor of InN at a carrier concentration of 1.11 Multiplication-Sign 10{sup 19} cm{sup -3} at 300 Degree-Sign {Kappa}.

  16. Survey of Transmission Cost Allocation Methodologies for Regional Transmission Organizations

    SciTech Connect (OSTI)

    Fink, S.; Porter, K.; Mudd, C.; Rogers, J.

    2011-02-01T23:59:59.000Z

    The report presents transmission cost allocation methodologies for reliability transmission projects, generation interconnection, and economic transmission projects for all Regional Transmission Organizations.

  17. Transmission electron microscopy of RSP Fe/Cr/Mn/Mo/C alloy. [Fe-3 wt % Cr-2 wt % Mn-0. 5 wt % Mo, -0. 3 wt % C

    SciTech Connect (OSTI)

    Rayment, J.J.; Thomas, G.

    1982-03-01T23:59:59.000Z

    Rapid solidification processing (RSP) has been carried out on an Fe/Cr/Mn/Mo/C alloy using both electron-beam melting and piston-and-anvil techniques. Preliminary TEM results show RSP produces a refined duplex microstructure of ferrite and martensite, with a typical ferrite grain size of 0.50 - 3.0 microns. This RSP microstructure is significantly different from that observed in the conventionally austenitized and quenched alloys - a lath martensitic microstructure with thin films of retained interlath austenite. The morphological change produced by RSP is accompanied by an increase in hardness from 48R/sub c/ to 61R/sub c/ (approx. 480 to 720 VHN). It is intended to use electron-beam specimens to examine the potential beneficial effect of RSP upon sliding wear resistance and, by careful TEM studies, it will be possible to characterize the microstructure and its role in the hardness and wear behavior of the RSP alloy.

  18. Merchant transmission investment

    E-Print Network [OSTI]

    Joskow, Paul L.

    2003-01-01T23:59:59.000Z

    We examine the performance attributes of a merchant transmission investment framework that relies on "market driven" transmission investment to provide the infrastructure to support competitive wholesale markets for ...

  19. Water-soluble polystyrene latexes as photoredox media. 1. Interfacial fluorescence quenching and triplet-state electron transfer from pyrene and 1-pyrenebutyric acid

    SciTech Connect (OSTI)

    Hsiao, J.S.; Webber, S.E. (Univ. of Texas, Austin (United States))

    1993-08-05T23:59:59.000Z

    Aromatic chromophores (pyrene and 1-pyrenebutyric acid) have been adsorbed on water-soluble polystyrene latex particles (commercially referred to as microspheres) from the aqueous phase. The fluorescence properties and quenching efficiencies of these chromophores have been measured using a zwitterionic viologen SPV (4,4[prime]-bipyridino-l,l[prime]-bis(propanesulfonate)). The quenching mechanism has been found to be diffusion controlled. The electron-transfer quenching of the triplet state by SPV was characterized. Triplet-state quenching does not occur for pyrene embedded in these polystyrene latexes in aqueous solution, which is attributed to the hydrophobic protection of the pyrene from the approach of water-soluble SPV. On the other hand, the efficiencies of charge separation for l-pyrenebutyric acid both in homogeneous aqueous solution and adsorbed on polystyrene latexes in aqueous solution were found to be high. It is proposed that the amphiphilic l-pyrenebutyric acid molecules prefer to reside at the aqueous interface of the latexes. These results demonstrate that [open quotes]compartmentalization[close quotes] of ion pairs, produced by redox quenching, can be achieved when l-pyrenebutyric acid molecules are located at these interfaces. This provides a strategy for more efficient utilization of excited-state redox processes. 17 refs., 9 figs., 5 tabs.

  20. SUBMITTED TO IEEE TRANSACTIONS ON POWER SYSTEMS, FEBRUARY 2002 1 Quantifying Transmission Reliability Margin

    E-Print Network [OSTI]

    SUBMITTED TO IEEE TRANSACTIONS ON POWER SYSTEMS, FEBRUARY 2002 1 Quantifying Transmission, power transmission reliability, power system security, power system availability I. Introduction Bulk power transfer capability computations have many uses in electric power system operation and planning

  1. Renewable Resource Integration Project - Scoping Study of Strategic Transmission, Operations, and Reliability Issues

    E-Print Network [OSTI]

    Budhraja, Vikram

    2008-01-01T23:59:59.000Z

    for transfer of renewable energy from the L.A.  Basin  Area April 2008.   Renewable Energy Transmission Initiative.  Commission  Competitive Renewable Energy Zones  California 

  2. Giga-bit optical data transmission module for Beam Instrumentation

    E-Print Network [OSTI]

    Roedne, L T; Cenkeramaddi, L R; Jiao, L

    Particle accelerators require electronic instrumentation for diagnostic, assessment and monitoring during operation of the transferring and circulating beams. A sensor located near the beam provides an electrical signal related to the observable quantity of interest. The front-end electronics provides analog-to-digital conversion of the quantity being observed and the generated data are to be transferred to the external digital back-end for data processing, and to display to the operators and logging. This research project investigates the feasibility of radiation-tolerant giga-bit data transmission over optic fibre for beam instrumentation applications, starting from the assessment of the state of the art technology, identification of challenges and proposal of a system level solution, which should be validated with a PCB design in an experimental setup. Radiation tolerance of 10 kGy (Si) Total Ionizing Dose (TID) over 10 years of operation, Bit Error Rate (BER) 10-6 or better. The findings and results of th...

  3. The Role of a Dipeptide Outer-Coordination Sphere on H2 -Production Catalysts: Influence on Catalytic Rates and Electron Transfer

    SciTech Connect (OSTI)

    Reback, Matthew L.; Ginovska-Pangovska, Bojana; Ho, Ming-Hsun; Jain, Avijita; Squier, Thomas C.; Raugei, Simone; Roberts, John A.; Shaw, Wendy J.

    2013-02-04T23:59:59.000Z

    The outer-coordination sphere of enzymes acts to fine-tune the active site reactivity and control catalytic rates, suggesting that incorporation of analogous structural elements into molecular catalysts may be necessary to achieve rates comparable to those observed in enzyme systems at low overpotentials. In this work, we evaluate the effect of an amino acid and dipeptide outer-coordination sphere on [Ni(PPh2NPh-R2)2]2+ hydrogen production catalysts. A series of 12 new complexes containing non-natural amino acids or dipeptides were prepared to test the effects of positioning, size, polarity and aromaticity on catalytic activity. The non-natural amino acid was either 3-(meta- or para-aminophenyl)propionic acid terminated as an acid, an ester or an amide. Dipeptides consisted of one of the non-natural amino acids coupled to one of four amino acid esters: alanine, serine, phenylalanine or tyrosine. All of the catalysts are active for hydrogen production, with rates averaging ~1000 s-1, 40% faster than the unmodified catalyst. Structure and polarity of the aliphatic or aromatic side chains of the C-terminal peptide do not strongly influence rates. However, the presence of an amide bond increases rates, suggesting a role for the amide in assisting catalysis. Overpotentials were lower with substituents at the N-phenyl meta position. This is consistent with slower electron transfer in the less compact, para-substituted complexes, as shown in digital simulations of catalyst cyclic voltammograms and computational modeling of the complexes. Combining the current results with insights from previous results, we propose a mechanism for the role of the amino acid and dipeptide based outer-coordination sphere in molecular hydrogen production catalysts.

  4. Transmission Commercial Project Integration

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Improvement (CBPI) Customer Forum Energy Imbalance Market Generator Interconnection Reform Implementation Network Integration Transmission Service (NT Service) Network Open...

  5. Dynamic Transfer Capability Analysis with Wind Farms and Dynamic Loads

    E-Print Network [OSTI]

    Pota, Himanshu Roy

    . An investigation on the effect of dynamics loads, wind farms and flexible AC transmission system (FACTS) devices capability unnecessarily limits the power transfers and is a costly and inefficient use of a network with increasing loads, the need to transfer power over long transmission lines increases. Deregulation

  6. Automated manual transmission controller

    DOE Patents [OSTI]

    Lawrie, Robert E. (Whitmore Lake, MI); Reed, Jr., Richard G. (Royal Oak, MI); Bernier, David R. (Rochester Hills, MI)

    1999-12-28T23:59:59.000Z

    A powertrain system for a hybrid vehicle. The hybrid vehicle includes a heat engine, such as a diesel engine, and an electric machine, which operates as both an electric motor and an alternator, to power the vehicle. The hybrid vehicle also includes a manual-style transmission configured to operate as an automatic transmission from the perspective of the driver. The engine and the electric machine drive an input shaft which in turn drives an output shaft of the transmission. In addition to driving the transmission, the electric machine regulates the speed of the input shaft in order to synchronize the input shaft during either an upshift or downshift of the transmission by either decreasing or increasing the speed of the input shaft. When decreasing the speed of the input shaft, the electric motor functions as an alternator to produce electrical energy which may be stored by a storage device. Operation of the transmission is controlled by a transmission controller which receives input signals and generates output signals to control shift and clutch motors to effect smooth launch, upshift shifts, and downshifts of the transmission, so that the transmission functions substantially as an automatic transmission from the perspective of the driver, while internally substantially functioning as a manual transmission.

  7. Transmission Rates of Gossypium mustelinum and G. tomentosum SNP Markers in Early-generation Backcrosses to Cotton

    E-Print Network [OSTI]

    Xu, Jiale

    2014-12-03T23:59:59.000Z

    for genetic improvement. Successful interspecific introgression efforts require the transmission of alien genes into the cultivated species and homologous recombination. Transmission distortion can restrict or preclude gene transfer, and reduced rates...

  8. EC Transmission Line Materials

    SciTech Connect (OSTI)

    Bigelow, Tim S [ORNL

    2012-05-01T23:59:59.000Z

    The purpose of this document is to identify materials acceptable for use in the US ITER Project Office (USIPO)-supplied components for the ITER Electron cyclotron Heating and Current Drive (ECH&CD) transmission lines (TL), PBS-52. The source of material property information for design analysis shall be either the applicable structural code or the ITER Material Properties Handbook. In the case of conflict, the ITER Material Properties Handbook shall take precedence. Materials selection, and use, shall follow the guidelines established in the Materials Assessment Report (MAR). Materials exposed to vacuum shall conform to the ITER Vacuum Handbook. [Ref. 2] Commercial materials shall conform to the applicable standard (e.g., ASTM, JIS, DIN) for the definition of their grade, physical, chemical and electrical properties and related testing. All materials for which a suitable certification from the supplier is not available shall be tested to determine the relevant properties, as part of the procurement. A complete traceability of all the materials including welding materials shall be provided. Halogenated materials (example: insulating materials) shall be forbidden in areas served by the detritiation systems. Exceptions must be approved by the Tritium System and Safety Section Responsible Officers.

  9. Directly correlated transmission electron microscopy and atom...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    well-separated oxides (NiAl2O4) precipitated along grain boundaries in the metal. Aluminum was depleted from the grain boundary between oxides and also from one side of the...

  10. Scientific Achievement Analytical Transmission Electron Microscopy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del Sol HomeFacebook Twitter Principalfuel cells"03, 2008Physicsintroduced

  11. Calculation of Ramp Response of Lossy Transmission Lines Using Two-port Network Functions

    E-Print Network [OSTI]

    Pedram, Massoud

    1 Calculation of Ramp Response of Lossy Transmission Lines Using Two-port Network Functions Payam-port representation of the transmission line and accounts for the output resistance of the driver and the line response of lossy transmission line which expands the reciprocal of transfer function of the system

  12. A stochastic framework for uncertainty analysis in electric power transmission systems with wind generation

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    of generating units, the transfer of electric power over networks of transmission lines and, finally1 A stochastic framework for uncertainty analysis in electric power transmission systems with wind an electric transmission network with wind power generation and their impact on its reliability. A stochastic

  13. Threshold Behavior in Electron-Transfer Collisions between Rubidium Atoms and C2F5Cl or C2F5I Molecules

    E-Print Network [OSTI]

    Brooks, Philip R.

    ,5 For example, SF6 attaches electrons to form a metastable SF6 - ion only at zero energy,6 whereas SF6 - (of

  14. Series Transmission Line Transformer

    DOE Patents [OSTI]

    Buckles, Robert A. (Livermore, CA); Booth, Rex (Livermore, CA); Yen, Boris T. (El Cerrito, CA)

    2004-06-29T23:59:59.000Z

    A series transmission line transformer is set forth which includes two or more of impedance matched sets of at least two transmissions lines such as shielded cables, connected in parallel at one end ans series at the other in a cascading fashion. The cables are wound about a magnetic core. The series transmission line transformer (STLT) which can provide for higher impedance ratios and bandwidths, which is scalable, and which is of simpler design and construction.

  15. The Nature of the Intramolecular Charge Transfer Excited State in p-Pyrrolocyanobenzene (PBN) and Other Derivatives of Benzene Substituted by Electron Donor and Acceptor

    E-Print Network [OSTI]

    Haas, Yehuda

    -Pyrrolocyanobenzene (PBN) and Other Derivatives of Benzene Substituted by Electron Donor and Acceptor Groups Shmuel Zilberg analysis of these compounds, in which benzene is substituted by an electron withdrawing group of benzene and is of a covalent nature. Light emission from this state is due to local excitation

  16. 2012 Transmission Rate Schedules

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2014 Transmission, Ancillary, and Control Area Service Rate Schedules and General Rate Schedule Provisions (FY 2014-2015) October 2013 United States Department of Energy...

  17. Electric Transmission Lines (Nebraska)

    Broader source: Energy.gov [DOE]

    The Public Service Commission has jurisdiction over all electricity transmission lines crossing over or under railroad tracks at public highway crossings. This section contains general regulations...

  18. Patterns of transmission investment

    E-Print Network [OSTI]

    Joskow, Paul L.

    2005-01-01T23:59:59.000Z

    This paper examines a number of issues associated with alternative analytical approaches for evaluating investments in electricity transmission infrastructure and alternative institutional arrangements to govern network ...

  19. Collaborative Transmission Technology Roadmap

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    techniques, and tools to analyze data from power quality recorders Size-up demand response opportunities Transmission level monitoring with PMUs is not sufficient and needs to...

  20. Magnetically insulated transmission line oscillator

    DOE Patents [OSTI]

    Bacon, Larry D. (Albuquerque, NM); Ballard, William P. (Albuquerque, NM); Clark, M. Collins (Albuquerque, NM); Marder, Barry M. (Albuquerque, NM)

    1988-01-01T23:59:59.000Z

    A magnetically insulated transmission line oscillator employs self-generated magnetic fields to generate microwave energy. An anode of the oscillator includes slow-wave structures which are formed of a plurality of thin conductive vanes defining cavities therebetween, and a gap is formed between the anode and a cathode of the oscillator. In response to a pulsed voltage applied to the anode and cathode, self-generated magnetic fields arfe produced in a cross-field orientation with respect to the orientation of the electric field between the anode and the cathode. The cross-field magnetic fields insulate the flow of electrons in the gap and confine the flow of electrons within the gap.

  1. Solar light transmission of polymer optical fibers

    SciTech Connect (OSTI)

    Tekelioglu, Murat [Mechanical Engineering Department, University of Nevada, Reno, NV 89557 (United States); Wood, Byard D. [Mechanical and Aerospace Engineering Department, Utah State University, Logan, UT 84322 (United States)

    2009-11-15T23:59:59.000Z

    Light transfer (10 m) has been shown in recent experiments that used large-core optical fibers. Theoretical models are not extensive, however, and a further correlation between the theory and experiments has not been given. In this paper, straight and bent fiber subsystem models are introduced with skew and meridional rays to predict the light transmission of POFs (plastic optical fibers). Such fibers have been realized, for example, in HSL (hybrid solar lighting) systems. The purpose of this paper is to combine the straight and bent fiber subsystems to estimate the light transmission of HSL systems. It is shown that meridional rays, for which the optical-loss parameters were estimated, better represent the experimental results compared to skew rays ({+-}5.3% vs {+-}24.7% of %-difference). Model predictions were compared with the results of a commercial software. Sensitivity analysis on the subsystems indicated the most-to-least significant parameters in light transmission. (author)

  2. Transmission Line Security Monitor

    ScienceCinema (OSTI)

    None

    2013-05-28T23:59:59.000Z

    The Transmission Line Security Monitor is a multi-sensor monitor that mounts directly on high-voltage transmission lines to detect, characterize and communicate terrorist activity, human tampering and threatening conditions around support towers. For more information about INL's critical infrastructure protection research, visit http://www.facebook.com/idahonationallaboratory.

  3. Transmission Line Security Monitor

    SciTech Connect (OSTI)

    None

    2011-01-01T23:59:59.000Z

    The Transmission Line Security Monitor is a multi-sensor monitor that mounts directly on high-voltage transmission lines to detect, characterize and communicate terrorist activity, human tampering and threatening conditions around support towers. For more information about INL's critical infrastructure protection research, visit http://www.facebook.com/idahonationallaboratory.

  4. Transmission Enhancement Technology Report

    E-Print Network [OSTI]

    of Existing Transmission 6 5. Potential New Equipment to Improve Transmission Capability 9 6. Potential New parties for the sites that should be studied as potential locations for new generation and to consult lignite and wind energy. " As per the requirements of the above-referenced Congressional direction

  5. Transmission Cost Allocation Methodologies for Regional Transmission Organizations

    SciTech Connect (OSTI)

    Fink, S.; Rogers, J.; Porter, K.

    2010-07-01T23:59:59.000Z

    This report describes transmission cost allocation methodologies for transmission projects developed to maintain or enhance reliability, to interconnect new generators, or to access new resources and enhance competitive bulk power markets, otherwise known as economic transmission projects.

  6. Electron microscopy and microanalysis Two transmission electron microscopes

    E-Print Network [OSTI]

    distribution (laser scatter- ing) q Powder surface area by gas adsorption (BET) Commercially Available of a failed austenitic stainless steel tube. The failure type is identified as a fatigue failure, due

  7. EC Transmission Line Risk Identification and Analysis

    SciTech Connect (OSTI)

    Bigelow, Tim S [ORNL

    2012-04-01T23:59:59.000Z

    The purpose of this document is to assist in evaluating and planning for the cost, schedule, and technical project risks associated with the delivery and operation of the EC (Electron cyclotron) transmission line system. In general, the major risks that are anticipated to be encountered during the project delivery phase associated with the implementation of the Procurement Arrangement for the EC transmission line system are associated with: (1) Undefined or changing requirements (e.g., functional or regulatory requirements) (2) Underperformance of prototype, first unit, or production components during testing (3) Unavailability of qualified vendors for critical components Technical risks associated with the design and operation of the system are also identified.

  8. Transfer matrix theory of monolayer graphene/bilayer graphene heterostructure superlattice

    SciTech Connect (OSTI)

    Wang, Yu, E-mail: ywang@semi.ac.cn [Department of Physics, Faculty of Science, Kunming University of Science and Technology, Kunming 650500 (China)

    2014-10-28T23:59:59.000Z

    We have formulated a transfer matrix method to investigate electronic properties of graphene heterostructure consisting of monolayer graphene and bilayer counterpart. By evaluating transmission, conductance, and band dispersion, we show that, irrespective of the different carrier chiralities in monolayer graphene and bilayer graphene, superlattice consisting of biased bilayer graphene barrier and monolayer graphene well can mimic the electronic properties of conventional semiconductor superlattice, displaying the extended subbands in the quantum tunneling regime and producing anisotropic minigaps for the classically allowed transport. Due to the lateral confinement, the lowest mode has shifted away from the charge neutral point of monolayer graphene component, opening a sizeable gap in concerned structure. Following the gate-field and geometry modulation, all electronic states and gaps between them can be externally engineered in an electric-controllable strategy.

  9. Fast and efficient single electron transfer between distant quantum dots S. Hermelin, S. Takada, M. Yamamoto, S. Tarucha, A. D. Wieck et al.

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Cooperative Research Project) Quantum Spin Information Project, Atsugi-shi, Kanagawa 243-0198, Japan 5 to manipulate a single electron or its spin quantum coherently.1­5 In addition, double dots--i.e., two dots thanks to surface-acoustic-wave assisted transport. In the context of quantum computing, displaced

  10. Semiconductor-Based Interfacial Electron-Transfer Reactivity: Decoupling Kinetics from pH-Dependent Band Energetics in a Dye-Sensitized Titanium Dioxide/Aqueous Solution

    E-Print Network [OSTI]

    H-Dependent Band Energetics in a Dye-Sensitized Titanium Dioxide/Aqueous Solution System Susan G. Yan and Joseph T energy of the electron in the electrode). The observed insensitivity to large changes in band-functionalized ruthenium bipyridyl complexes to- gether with high-area nanocrystalline titanium dioxide films.2

  11. Designing electricity transmission auctions

    E-Print Network [OSTI]

    Greve, Thomas; Pollitt, Michael G.

    2012-10-26T23:59:59.000Z

    The UK has ambitious plans for exploiting offshore wind for electricity production in order to meet its challenging target under the EU Renewable Energy Directive. This could involve investing up to 20bn in transmission assets to bring electricity...

  12. Transmission Services Bulletin

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Standard Time On the first Sunday in November Transmission Services sets clocks from Daylight Savings Time (PD) back to Standard Time (PS). At 02:00 the time becomes 01:00. In...

  13. Downhole transmission system

    DOE Patents [OSTI]

    Hall, David R. (Provo, UT); Fox, Joe (Spanish Fork, UT)

    2008-01-15T23:59:59.000Z

    A transmission system in a downhole component comprises a data transmission element in both ends of the downhole component. Each data transmission element houses an electrically conducting coil in a MCEI circular trough. An electrical conductor connects both the transmission elements. The electrical conductor comprises at least three electrically conductive elements insulated from each other. In the preferred embodiment the electrical conductor comprises an electrically conducting outer shield, an electrically conducting inner shield and an electrical conducting core. In some embodiments of the present invention, the electrical conductor comprises an electrically insulating jacket. In other embodiments, the electrical conductor comprises a pair of twisted wires. In some embodiments, the electrical conductor comprises semi-conductive material.

  14. Electric Transmission Lines (Iowa)

    Broader source: Energy.gov [DOE]

    Electric transmission lines capable of operating at 69 kV or greater cannot be constructed along, across, or over any public highways or grounds outside of cities without a franchise from the...

  15. Down hole transmission system

    DOE Patents [OSTI]

    Hall, David R. (Provo, UT); Hall, Jr., H. Tracy (Provo, UT)

    2007-07-24T23:59:59.000Z

    A transmission system in a downhole component comprises a data transmission element in both ends of the downhole component. Each data transmission element houses an electrically conducting coil in a MCEI circular trough. The electrically conducting coil comprises at least two generally fractional loops. In the preferred embodiment, the transmission elements are connected by an electrical conductor. Preferably, the electrical conductor is a coaxial cable. Preferably, the MCEI trough comprises ferrite. In the preferred embodiment, the fractional loops are connected by a connecting cable. In one aspect of the present invention, the connecting cable is a pair of twisted wires. In one embodiment the connecting cable is a shielded pair of twisted wires. In another aspect of the present invention, the connecting cable is a coaxial cable. The connecting cable may be disposed outside of the MCEI circular trough.

  16. Flexible Transmission in the Smart Grid

    E-Print Network [OSTI]

    Hedman, Kory Walter

    2010-01-01T23:59:59.000Z

    Planning . 102 vi Transmission Line Maintenance Scheduling 103 Just-in-time Transmission 103 Flexible Transmission in the Smart Grid

  17. Honda Transmission Technical Center

    High Performance Buildings Database

    Russells Point, OH The Honda Transmission Technical Center is located on the Honda of America Manufacturing Plant facility site in Russells Point, Ohio. This facility is used for product engineering and market quality testing and analysis of automatic transmissions. The building contains a large workshop area for ten cars, a future dynamometer, two laboratories, an open office area, three conference rooms, a break room, restrooms, and related support areas.

  18. Bulk Power Transmission Study

    E-Print Network [OSTI]

    John, T.

    BULK POWER TRANSMISSION STUDY TOMMY JOH~ P. E. Manager of Resource Recovery Waste Management of North America, Inc. Houston, Texas Texans now have a choice. We can become more efficient and maintain our standard of living, or we can... continue business as usual and watch our standard of living erode from competition from other regions. In the past, except for improving reliability, there was no need for a strong transmission system. When Texas generation was primarily gas fueled...

  19. Standard Practice for Dosimetry of Proton Beams for use in Radiation Effects Testing of Electronics

    E-Print Network [OSTI]

    McMahan, Margaret A.

    2008-01-01T23:59:59.000Z

    1000 Gy Transmission Ion Chamber (TIC) Secondary ElectronScintillator (SC) Thimble Ion Chamber (IC) Faraday Cup (FC)either a transmission ion chamber [TIC] (usually operated in

  20. Dynamical steering in an electron transfer surface reaction: Oriented NO(v = 3, 0.08 < E{sub i} < 0.89 eV) relaxation in collisions with a Au(111) surface

    SciTech Connect (OSTI)

    Bartels, Nils; Golibrzuch, Kai; Bartels, Christof; Schäfer, Tim, E-mail: tschaef4@gwdg.de [Institute of Physical Chemistry, Georg-August University of Göttingen, Tammannstraße 6, 37077 Göttingen (Germany)] [Institute of Physical Chemistry, Georg-August University of Göttingen, Tammannstraße 6, 37077 Göttingen (Germany); Chen, Li [Department of Dynamics at Surfaces, Max Planck Institute for Biophysical Chemistry, Am Faßberg 11, 37077 Göttingen (Germany)] [Department of Dynamics at Surfaces, Max Planck Institute for Biophysical Chemistry, Am Faßberg 11, 37077 Göttingen (Germany); Auerbach, Daniel J.; Wodtke, Alec M. [Institute of Physical Chemistry, Georg-August University of Göttingen, Tammannstraße 6, 37077 Göttingen (Germany) [Institute of Physical Chemistry, Georg-August University of Göttingen, Tammannstraße 6, 37077 Göttingen (Germany); Department of Dynamics at Surfaces, Max Planck Institute for Biophysical Chemistry, Am Faßberg 11, 37077 Göttingen (Germany)

    2014-02-07T23:59:59.000Z

    We report measurements of the incidence translational energy dependence of steric effects in collisions of NO(v = 3) molecules with a Au(111) surface using a recently developed technique to orient beams of vibrationally excited NO molecules at incidence energies of translation between 0.08 and 0.89 eV. Incidence orientation dependent vibrational state distributions of scattered molecules are detected by means of resonance enhanced multiphoton ionization spectroscopy. Molecules oriented with the N-end towards the surface exhibit a higher vibrational relaxation probability than those oriented with the O-end towards the surface. This strong orientation dependence arises from the orientation dependence of the underlying electron transfer reaction responsible for the vibrational relaxation. At reduced incidence translational energy, we observe a reduced steric effect. This reflects dynamical steering and re-orientation of the NO molecule upon its approach to the surface.

  1. Transfer of a weakly bound electron in collisions of Rydberg atoms with neutral particles. I. Long-range interaction effects in the ionic-covalent coupling

    SciTech Connect (OSTI)

    Lebedev, V. S., E-mail: vlebedev@sci.lebedev.ru; Narits, A. A. [Russian Academy of Sciences, Lebedev Physics Institute (Russian Federation)] [Russian Academy of Sciences, Lebedev Physics Institute (Russian Federation)

    2013-10-15T23:59:59.000Z

    Ion-pair formation processes are studied in collisions of Rydberg atoms with neutral particles possessing small electron affinities. Nonadiabatic transitions from a Rydberg covalent term to an ionic term of a quasi-molecule are considered using the modified Landau-Zener theory supplemented with calculation of survival factors of an anion decaying in the Coulomb field of a positive ion core. Using the technique of irreducible tensor operators and the momentum representation of the wavefunction of a highly excited atom, exact expressions are obtained for transition matrix elements and the ionic-covalent coupling parameter. The approach developed in the paper provides the description beyond the scope of a conventional assumption about a small variation of the wavefunction of the Rydberg atom on the range of electron coordinates determined by the characteristic radius of the wavefunction of the anion. This allows one to correctly consider long-range effects of the interaction between a weakly bound electron and the neutral core of a negative ion in processes under study. It is shown by the example of thermal collisions of Xe(nf) atoms with CH{sub 3}CN molecules that this is very important for a reliable quantitative description of anion formation with a low binding energy. The results are compared with experiments and calculations performed within the framework of a number of approximate methods.

  2. Spring 2014 Heat Transfer -2

    E-Print Network [OSTI]

    Virginia Tech

    Spring 2014 Heat Transfer - 2 A thin electronic chip is in the shape of a square wafer, b = 1 cm surface of the chip with a heat transfer coefficient of h = 100 W/m2 -K. Assume the chip has a uniform per side with a mass of m = 0.3 grams and specific heat of C = 103 J/kg-K. The chip is mounted

  3. PHYSICAL REVIEW B 87, 144301 (2013) Parametric amplification in Josephson junction embedded transmission lines

    E-Print Network [OSTI]

    Friedland, Lazar

    transmission lines O. Yaakobi,1,* L. Friedland,2 C. Macklin,3 and I. Siddiqi3 1 INRS-EMT, 1650 Boul. Lionel; published 1 April 2013) An electronic transmission line that contains an array of nonlinear elements of the node flux along the transmission line is derived. It is shown that due to the nonlinearity

  4. Hybrid Transmission Corridor study

    SciTech Connect (OSTI)

    Clairmont, B.A.; Johnson, G.B.; Zaffanella, L.E. (General Electric Co., Lenox, MA (United States))

    1992-06-01T23:59:59.000Z

    Hybrid Transmission Corridors are areas where High Voltage Alternating Current (HVAC) transmission lines and High Voltage Direct Current (HVDC) transmission lines exist in close proximity of each other. Because of the acceptance of HVDC as a means of transporting electric power over long distances and the difficulties associated with obtaining new right-of-ways, HVDC lines may have to share the same transmission corridor with HVAC lines. The interactions between conductors energized with different types of voltages causes changes in the electrical stresses applied to the conductors and insulators. As a result, corona phenomena, field effects and insulation performance can be affected. This report presents the results of an investigation of the HVAC-HVDC interaction and its effect on corona and AC and DC electric field phenomena. The method of investigation was based on calculation methods developed at the EPRI High Voltage Transmission Research Center (HVTRC) and supported by the results of full and reduced-scale line tests. Also, a survey of existing hybrid corridors is given along with the results of measurements made at one of those corridors. A number of examples in which an existing AC corridor may be transformed into a hybrid corridor are discussed. The main result of the research is an analytical/empirical model for predicting the electrical/environmental performance of hybrid corridors, a definition of ACDC interaction and a set of criteria for specifying when the interaction becomes significant, and a set of design rules.

  5. Analyses of power system vulnerability and total transfer capability

    E-Print Network [OSTI]

    Yu, Xingbin

    2006-04-12T23:59:59.000Z

    limits. Both steady state and dynamic security assessments are included in the process of obtaining total transfer capability. Particularly, the effect of FACTS (Flexible AC Transmission Systems) devices on TTC is examined. FACTS devices have been shown...

  6. Nanowires, Capacitors, and Other Novel Outer-Surface Components Involved in Electron Transfer to Fe(III) Oxides in Geobacter Species

    SciTech Connect (OSTI)

    Lovley, Derek R.

    2005-06-01T23:59:59.000Z

    In the past year studies have primarily focused on elucidating the role of pili in electron transport to Fe(III) oxide in Geobacter sulfurreducens. As summarized in last year's report, it was previously found that pili are specifically expressed during growth on Fe(III) oxide and that Fe(III) oxide reduction is inhibited if the gene for the structural pilin protein is deleted. However, it was also found that a pilin-deficient mutant of G. sulfurreducens could attached to Fe(III) oxide as well as wild type.

  7. Printed circuit dispersive transmission line

    DOE Patents [OSTI]

    Ikezi, H.; Lin-Liu, Y.R.; DeGrassie, J.S.

    1991-08-27T23:59:59.000Z

    A printed circuit dispersive transmission line structure is disclosed comprising an insulator, a ground plane formed on one surface of the insulator, a first transmission line formed on a second surface of the insulator, and a second transmission line also formed on the second surface of the insulator and of longer length than the first transmission line and periodically intersecting the first transmission line. In a preferred embodiment, the transmission line structure exhibits highly dispersive characteristics by designing the length of one of the transmission line between two adjacent periodic intersections to be longer than the other. 5 figures.

  8. Low Frequency Transmission Final Project Report

    E-Print Network [OSTI]

    to HVDC transmission and conventional AC transmission in different configurations. The issue is quite

  9. Efficient performance optimisation of wireless power transmission using

    E-Print Network [OSTI]

    Myung, Noh-Hoon

    Efficient performance optimisation of wireless power transmission using genetic algorithm Junghoon [1], are attracting attention for a mid-range energy transfer because these systems are so useful) to analyse and extract the parameters from the equivalent circuit model and to calculate the optimal values

  10. PLM: Fast Convergence for Cumulative Layered Multicast Transmission Schemes

    E-Print Network [OSTI]

    Legout, Arnaud

    PLM: Fast Convergence for Cumulative Layered Multicast Transmission Schemes A. Legout and E. W- ticast congestion control protocol (called PLM) for audio/video and file transfer applications based PLM for a large variety of scenarios and show that it converges fast to the optimal link utilization

  11. Barriers to innovation transfer in a remote and rural health, social care & housing setting 

    E-Print Network [OSTI]

    Gallimore, Annette

    2011-11-25T23:59:59.000Z

    and insufficient slack resources arising from the rural setting were key reasons for the delay in practice transfer. The project focus shifted from the transfer of electronic single shared assessment to the transfer of improvements to single shared assessment...

  12. Omega Transmission Lines

    E-Print Network [OSTI]

    Vehmas, Joni

    2013-01-01T23:59:59.000Z

    In this paper, we show how bi-anisotropic media with omega-type response can be realized using periodically loaded transmission lines. General conditions for the needed unit cell circuit block are derived. Also, an implementation is shown and analyzed.

  13. Borehole data transmission apparatus

    DOE Patents [OSTI]

    Kotlyar, O.M.

    1993-03-23T23:59:59.000Z

    A borehole data transmission apparatus is described whereby a centrifugal pump impeller(s) is used to provide a turbine stage having substantial pressure characteristics in response to changing rotational speed of a shaft for the pressure pulsing of data from the borehole through the drilling mud to the surface of the earth.

  14. Borehole data transmission apparatus

    DOE Patents [OSTI]

    Kotlyar, Oleg M. (1739 Grandview #2, Idaho Falls, ID 83402)

    1993-01-01T23:59:59.000Z

    A borehole data transmission apparatus whereby a centrifugal pump impeller(s) is used to provide a turbine stage having substantial pressure characteristics in response to changing rotational speed of a shaft for the pressure pulsing of data from the borehole through the drilling mud to the surface of the earth.

  15. Autonomous data transmission apparatus

    DOE Patents [OSTI]

    Kotlyar, Oleg M. (4675 W. 3825 S, Salt Lake City, UT 84120)

    1997-01-01T23:59:59.000Z

    A autonomous borehole data transmission apparatus for transmitting measurement data from measuring instruments at the downhole end of a drill string by generating pressure pulses utilizing a transducer longitudinally responsive to magnetic field pulses caused by electrical pulses corresponding to the measured downhole parameters.

  16. Autonomous data transmission apparatus

    DOE Patents [OSTI]

    Kotlyar, O.M.

    1997-03-25T23:59:59.000Z

    A autonomous borehole data transmission apparatus is described for transmitting measurement data from measuring instruments at the downhole end of a drill string by generating pressure pulses utilizing a transducer longitudinally responsive to magnetic field pulses caused by electrical pulses corresponding to the measured downhole parameters. 4 figs.

  17. Transmission SEAB Presentation | Department of Energy

    Broader source: Energy.gov (indexed) [DOE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOn April 23,EnergyChicopeeTechnologyfact sheetTransferring the Wayne, NJ,Know?'Transmission

  18. Transmission of Serial Data Using Inductive Data Transfer

    E-Print Network [OSTI]

    Wood, Stephen L.

    ,000 ohm 5% 3 22,000 ohm 5% 1 Capacitors .001 micro Farad 2 .1 micro Farad 4 10 micro Farad 2 Integrated Plexiglas 2-inch diameter circle Super glue 1 tube #12;Recommended tools for construction Wire strippers

  19. One-electron-transfer reactions of the couple SO/sub 2//SO/sub 2//sup -/ in aqueous solutions. Pulse radiolytic and cyclic voltametric studies

    SciTech Connect (OSTI)

    Neta, P.; Huie, R.E.; Harriman, A.

    1987-03-12T23:59:59.000Z

    Rate constants for one-electron reduction of SO/sub 2/ by several radicals and for reduction of several compounds by SO/sub 2//sup .-/ radicals were determined by pulse radiolysis at pH 1. SO/sub 2/ is reduced by the (CH/sub 3/)/sub 2/COH radicals with k = 2.1 x 10/sup 9/ M/sup -1/ s/sup -1/ and by viologen radicals and certain porphyrin ..pi..-radical anions with k approx. 10/sup 8/-10/sup 9/ M/sup -1/ s/sup -1/. The SO/sub 2//sup .-/ radical reduces compounds which have reduction potentials more positive than -0.28 V. The rate constants for these reductions vary from < 10/sup 7/ to > 10/sup 9/ M/sup -1/ s/sup -1/ and depend on the redox potentials of the compounds and on other properties such as charge and self-exchange rate. The reduction potentials for SO/sub 2/ and for the porphyrins were determined by cyclic voltametry under identical conditions. These reduction potentials were used along with the rate constants and previously reported self-exchange rates to estimate the self-exchange rate for the couple SO/sub 2//SO/sub 2//sup .-/ in acidic solutions. The calculated values were found to vary over many orders of magnitude, similar to the situation reported before for the O/sub 2//O/sub 2//sup -/ couple.

  20. Free electron laser

    DOE Patents [OSTI]

    Villa, Francesco (Alameda, CA)

    1990-01-01T23:59:59.000Z

    A high gain, single-pass free electron laser formed of a high brilliance electron injector source, a linear accelerator which imparts high energy to the electron beam, and an undulator capable of extremely high magnetic fields, yet with a very short period. The electron injector source is the first stage (gap) of the linear accelerator or a radial line transformer driven by fast circular switch. The linear accelerator is formed of a plurality of accelerating gaps arranged in series. These gaps are energized in sequence by releasing a single pulse of energy which propagates simultaneously along a plurality of transmission lines, each of which feeds the gaps. The transmission lines are graduated in length so that pulse power is present at each gap as the accelerated electrons pass therethrough. The transmission lines for each gap are open circuited at their ends. The undualtor has a structure similar to the accelerator, except that the transmission lines for each gap are substantially short circuited at their ends, thus converting the electric field into magnetic field. A small amount of resistance is retained in order to generate a small electric field for replenishing the electron bunch with the energy lost as it traverses through the undulator structure.

  1. Characterization and Development of Advanced Heat Transfer Technologie...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    May 18-22, 2009 -- Washington D.C. ape11kelly.pdf More Documents & Publications Characterization and Development of Advanced Heat Transfer Technologies Advanced Power Electronics...

  2. Drill string transmission line

    DOE Patents [OSTI]

    Hall, David R. (Provo, UT); Hall, Jr., H. Tracy (Provo, UT); Pixton, David S. (Lehi, UT); Bradford, Kline (Orem, UT); Fox, Joe (Spanish Fork, UT)

    2006-03-28T23:59:59.000Z

    A transmission line assembly for transmitting information along a downhole tool comprising a pin end, a box end, and a central bore traveling between the pin end and the box end, is disclosed in one embodiment of the invention as including a protective conduit. A transmission line is routed through the protective conduit. The protective conduit is routed through the central bore and the ends of the protective conduit are routed through channels formed in the pin end and box end of the downhole tool. The protective conduit is elastically forced into a spiral or other non-linear path along the interior surface of the central bore by compressing the protective conduit to a length within the downhole tool shorter than the protective conduit.

  3. Transmission line: design manual

    SciTech Connect (OSTI)

    Farr, H.H.

    1980-01-01T23:59:59.000Z

    The purpose of this manual is to outline the various requirements for, and the procedures to be followed in the design of power transmission lines by the Bureau of Reclamation, US Department of the Interior. Numerous design studies, which have been made on specific aspects of transmission line design, are included with explanations of their applications. Information is presented concerning such aspects as selection of type of construction, conductor sags and tensions, insulation, lightning protection, clearance patterns, galloping conductors, structure limitation and guying charts, and structure spotting. Structure design examples are limited to wood-pole construction. Interpretations of the National Electrical Safety Code and other codes are made as required. Some of the example problems were developed when the sixth edition of NESC was current, and are so noted; however, most examples use the 1977 edition of NESC.

  4. Patterns of Transmission Investment

    E-Print Network [OSTI]

    Joskow, Paul

    2006-03-14T23:59:59.000Z

    while providing imperfect protection against abusive self-dealing behavior by the TSO. The creation of truly independent TSOs reduces the regulatory burdens and creates entities whose management focuses on the transmission business. 15... of physical components that are to be added to the network or to replace components that are already in the network. They include: a. new relays and switches b. new remote monitoring and control equipment c. transformer upgrades d. substation...

  5. Excitation energy transfer in the photosystem I

    SciTech Connect (OSTI)

    Webber, Andrew N

    2012-09-25T23:59:59.000Z

    Photosystem I is a multimeric pigment protein complex in plants, green alage and cyanobacteria that functions in series with Photosystem II to use light energy to oxidize water and reduce carbon dioxide. The Photosystem I core complex contains 96 chlorophyll a molecules and 22 carotenoids that are involved in light harvesting and electron transfer. In eucaryotes, PSI also has a peripheral light harvesting complex I (LHCI). The role of specific chlorophylls in excitation and electron transfer are still unresolved. In particular, the role of so-called bridging chlorophylls, located between the bulk antenna and the core electron transfer chain, in the transfer of excitation energy to the reaction center are unknown. During the past funding period, site directed mutagenesis has been used to create mutants that effect the physical properties of these key chlorophylls, and to explore how this alters the function of the photosystem. Studying these mutants using ultrafast absorption spectroscopy has led to a better understanding of the process by which excitation energy is transferred from the antenna chlorophylls to the electron transfer chain chlorophylls, and what the role of connecting chlorophylls and A_0 chlorophylls is in this process. We have also used these mutants to investigate whch of the central group of six chlorophylls are involved in the primary steps of charge separation and electron transfer.

  6. Geothermal Resources and Transmission Planning

    Broader source: Energy.gov [DOE]

    This project addresses transmission-related barriers to utility-scale deployment of geothermal electric generation technologies.

  7. Boardman to Hemingway Transmission Project

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Improvement (CBPI) Customer Forum Energy Imbalance Market Generator Interconnection Reform Implementation Network Integration Transmission Service (NT Service) Network Open...

  8. Transmission Issues Policy Steering Committee

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Business Practices CommitteesTeams Joint Operating Committee Transmission Issues Policy Steering Committee Customer Training Interconnection Notices Rates Standards of...

  9. Energetics and Dynamics of Electron Transfer and Proton Transfer...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and MnIII(salen)+ with several angiotensin peptide analogs was studied using a Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS) specially equipped to...

  10. Automated manual transmission clutch controller

    DOE Patents [OSTI]

    Lawrie, Robert E. (9375 Kearney Rd., Whitmore Lake, MI 48189); Reed, Jr., Richard G. (3003 Bembridge, Royal Oak, MI 48073); Rausen, David J. (519 S. Gaylord St., Denver, CO 80209)

    1999-11-30T23:59:59.000Z

    A powertrain system for a hybrid vehicle. The hybrid vehicle includes a heat engine, such as a diesel engine, and an electric machine, which operates as both an electric motor and an alternator, to power the vehicle. The hybrid vehicle also includes a manual-style transmission configured to operate as an automatic transmission from the perspective of the driver. The engine and the electric machine drive an input shaft which in turn drives an output shaft of the transmission. In addition to driving the transmission, the electric machine regulates the speed of the input shaft in order to synchronize the input shaft during either an upshift or downshift of the transmission by either decreasing or increasing the speed of the input shaft. When decreasing the speed of the input shaft, the electric motor functions as an alternator to produce electrical energy which may be stored by a storage device. Operation of the transmission is controlled by a transmission controller which receives input signals and generates output signals to control shift and clutch motors to effect smooth launch, upshift shifts, and downshifts of the transmission, so that the transmission functions substantially as an automatic transmission from the perspective of the driver, while internally substantially functioning as a manual transmission.

  11. Transmission - Contact Information

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del SolStrengthening a solidSynthesisAppliances » DataContact-Information-Transmission

  12. Transmission | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are beingZealand Jump to:Ezfeedflag JumpID-f <MaintainedInformationThePtyTownTrama TecnoTransmission

  13. Transmission | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov YouKizildere IRaghuraji Agro IndustriesTown of Ladoga, Indiana (Utility Company) JumpTradeWindPrepared asTransmission

  14. Initial Studies Toward Real-Time Transmission Path Rating

    SciTech Connect (OSTI)

    Singh, Ruchi; Diao, Ruisheng; Cai, Niannian; Huang, Zhenyu; Tuck, Brian; Guo, Xinxin

    2012-07-26T23:59:59.000Z

    Demand continues to increase while transmission line construction is being constrained by multiple factors— economic, environmental, and political. Effective and efficient utilization of transmission lines is thus of great importance in an open access environment. Large blocks of power are transferred from areas with inexpensive generation to heavy load demand areas or areas with high generation costs. This results in some transmission paths being loaded closer to their path ratings, which limits further power transfer between areas. Traditionally, rating of important paths was determined off line by assuming the worst-case study scenario; once determined, it could be used for years. With increasing uncertainty arising from rapid growth of renewable energy and smart technologies, path rating studies are needed in near-real time to account for the latest system status and support a reliable and economic power grid. This paper adopts a simplified procedure based on standards of the North American Electric Reliability Corporation (NERC) to determine total transfer capability (TTC) or transfer limit for the purpose of demonstrating the benefits and necessity of real-time path rating. Initial studies are conducted to compute TTC of a two-area test system and a 39-bus test system. Results indicate that path rating can be significantly affected by loading conditions, generator schedules, system topology and other factors.

  15. Colorado Electrical Transmission Grid

    SciTech Connect (OSTI)

    Zehner, Richard E.

    2012-02-01T23:59:59.000Z

    Citation Information: Originator: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Originator: Xcel Energy Publication Date: 2012 Title: Colorado XcelEnergy NonXcel Transmission Network Edition: First Publication Information: Publication Place: Earth Science & Observation Center, Cooperative Institute for Research in Environmental Science (CIRES), University of Colorado, Boulder Publisher: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Description: This layer contains transmission network of Colorado Spatial Domain: Extent: Top: 4540689.017558 m Left: 160606.141934 m Right: 758715.946645 m Bottom: 4098910.893397m Contact Information: Contact Organization: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Contact Person: Khalid Hussein Address: CIRES, Ekeley Building Earth Science & Observation Center (ESOC) 216 UCB City: Boulder State: CO Postal Code: 80309-0216 Country: USA Contact Telephone: 303-492-6782 Spatial Reference Information: Coordinate System: Universal Transverse Mercator (UTM) WGS’1984 Zone 13N False Easting: 500000.00000000 False Northing: 0.00000000 Central Meridian: -105.00000000 Scale Factor: 0.99960000 Latitude of Origin: 0.00000000 Linear Unit: Meter Datum: World Geodetic System ’1984 (WGS ’1984) Prime Meridian: Greenwich Angular Unit: Degree Digital Form: Format Name: Shapefile

  16. Manual transmission shift linkage

    SciTech Connect (OSTI)

    Sewell, J.S.

    1991-10-01T23:59:59.000Z

    This patent describes a sliding gear manual transmission (10) for an automotive vehicle including a transmission housing (11), an input shaft (12) journalled in the housing, an output shaft (13) axially aligned with the input shaft and journalled in the housing, a countershaft (15) journalled in the housing and carrying a cluster gear (17) thereon, the input shaft (12) terminating in an input gear (14), a plurality of gears (26,27,28,29,31,31) on the output shaft (13) in meshing engagement with the cluster gear (17), and a plurality of synchronizing clutches (36,38,41,42) on the output shaft and countershaft for engagement of gear ratios of the meshing gears, and an axially movable and rotatable shift rail (81) located in the housing and operatively connected to a shift lever (82) actuated by the vehicle operator, the improvement comprising an auxiliary shift rail (98) located in the housing (11) generally paralleling the first mentioned shift rail (81) to provide for actuation of fifth, sixth and reverse gears the auxiliary shift rail (98) having a 5-6 shift arm (104) journalled thereon for axial movement relative thereto, and a reverse shift arm (99) rotatably mounted thereon for axial movement therewith.

  17. Localized radio frequency communication using asynchronous transfer mode protocol

    DOE Patents [OSTI]

    Witzke, Edward L. (Edgewood, NM); Robertson, Perry J. (Albuquerque, NM); Pierson, Lyndon G. (Albuquerque, NM)

    2007-08-14T23:59:59.000Z

    A localized wireless communication system for communication between a plurality of circuit boards, and between electronic components on the circuit boards. Transceivers are located on each circuit board and electronic component. The transceivers communicate with one another over spread spectrum radio frequencies. An asynchronous transfer mode protocol controls communication flow with asynchronous transfer mode switches located on the circuit boards.

  18. Transmission SEAB Presentation

    Broader source: Energy.gov (indexed) [DOE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOn April 23,EnergyChicopeeTechnologyfact sheetTransferring the Wayne, NJ,Know?'

  19. Application of Electron Transfer Dissociation Mass Spectrometry...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    glycation of peptides and proteins by D-glucose has important implications in diabetes mellitus research, particularly in the context of development of diabetic...

  20. Microsoft Word - Electron transfer.doc

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHighandSWPA / SPRA / USACE SWPAURTeC:8CO 2Dances done atReduced

  1. Transmission Planning | Department of Energy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Improving Performance of Federal Permitting and Review of Infrastructure Projects Energy Corridors on Federal Lands Transmission Projects Proposed Under EPAct Section 1222 Activity...

  2. AGENDA: PETROLEUM PRODUCT TRANSMISSION & DISTRIBUTION

    Broader source: Energy.gov [DOE]

    The agenda for the Quadrennial Energy Review (QER) public stakeholder meeting in New Orleans on petroleum product transmission, distribution, and storage.

  3. Raj JainThe Ohio State University Data TransmissionData TransmissionData Transmission

    E-Print Network [OSTI]

    Jain, Raj

    The Ohio State University 2-14 Bit Error RateBit Error RateBit Error Rate Energy/bit Eb =STb, where TbRaj JainThe Ohio State University 2-1 Data TransmissionData TransmissionData Transmission Raj Jain Professor of CIS The Ohio State University Columbus, OH 43210 Jain@ACM.Org http://www.cis.ohio

  4. HVDC power transmission technology assessment

    SciTech Connect (OSTI)

    Hauth, R.L.; Tatro, P.J.; Railing, B.D. [New England Power Service Co., Westborough, MA (United States); Johnson, B.K.; Stewart, J.R. [Power Technologies, Inc., Schenectady, NY (United States); Fink, J.L.

    1997-04-01T23:59:59.000Z

    The purpose of this study was to develop an assessment of the national utility system`s needs for electric transmission during the period 1995-2020 that could be met by future reduced-cost HVDC systems. The assessment was to include an economic evaluation of HVDC as a means for meeting those needs as well as a comparison with competing technologies such as ac transmission with and without Flexible AC Transmission System (FACTS) controllers. The role of force commutated dc converters was to be assumed where appropriate. The assessment begins by identifying the general needs for transmission in the U.S. in the context of a future deregulated power industry. The possible roles for direct current transmission are then postulated in terms of representative scenarios. A few of the scenarios are illustrated with the help of actual U.S. system examples. non-traditional applications as well as traditional applications such as long lines and asynchronous interconnections are discussed. The classical ``break-even distance`` concept for comparing HVDC and ac lines is used to assess the selected scenarios. The impact of reduced-cost converters is reflected in terms of the break-even distance. This report presents a comprehensive review of the functional benefits of HVDC transmission and updated cost data for both ac and dc system components. It also provides some provocative thoughts on how direct current transmission might be applied to better utilize and expand our nation`s increasingly stressed transmission assets.

  5. Direct current power transmission systems

    SciTech Connect (OSTI)

    Padiyar, K.R.

    1991-01-01T23:59:59.000Z

    This book represents text on HVDC transmission available. It deals with the various aspects of the state of the art in HVDC transmission technology. This book presents many aspects of interactions of AC/DC systems. Modeling and analysis of DC systems are also discussed in detail.

  6. The Cost of Transmission for Wind Energy: A Review of Transmission Planning Studies

    E-Print Network [OSTI]

    Mills, Andrew D.

    2009-01-01T23:59:59.000Z

    Wind Energy Access, Transmission, and Intermittency Really Cost?transmission cost barrier for wind energy. A secondary goalfocus on the cost of transmission for wind energy does not

  7. Key-shift transmission

    SciTech Connect (OSTI)

    Nemoto, S.

    1989-03-07T23:59:59.000Z

    A key-shift transmission is described, characterized by the speed-change shaft being divided into a pair of trough-shaped shaft halves each having an arched inner surface which defines a part of a cylindrical bore extending axially through the speed-change shaft thereby the shaft being formed into a hollow shaft, and by each of the shaft halves including a pair of flattened end surfaces which extend axially of each shaft half at both sides of the inner surface, one of the end surfaces having thereon an axially elongated projection and the other of the end surfaces having herein an axially elongated recess of a depth smaller than the height of the projection. The pair of shaft halves are engaged to each other co-rotatably by fitting the projections of the respective shaft halves into the recesses of the respective shaft halves so as to form in an outer surface of the speed-change shaft a pair of elongated axial grooves which are located radially outwardly of the elongated projections of the respective shaft halves and between the flattened end surfaces of the respective shaft halves. A pair of the shift keys are disposed within the pair of elongated axial grooves.

  8. Regional Transmission Projects: Finding Solutions

    SciTech Connect (OSTI)

    The Keystone Center

    2005-06-15T23:59:59.000Z

    The Keystone Center convened and facilitated a year-long Dialogue on "Regional Transmission Projects: Finding Solutions" to develop recommendations that will help address the difficult and contentious issues related to expansions of regional electric transmission systems that are needed for reliable and economic transmission of power within and across regions. This effort brought together a cross-section of affected stakeholders and thought leaders to address the problem with the collective wisdom of their experience and interests. Transmission owners sat at the table with consumer advocates and environmental organizations. Representatives from regional transmission organizations exchanged ideas with state and federal regulators. Generation developers explored common interests with public power suppliers. Together, the Dialogue participants developed consensus solutions about how to begin unraveling some of the more intractable issues surrounding identification of need, allocation of costs, and reaching consensus on siting issues that can frustrate the development of regional transmission infrastructure. The recommendations fall into three broad categories: 1. Recommendations on appropriate institutional arrangements and processes for achieving regional consensus on the need for new or expanded transmission infrastructure 2. Recommendations on the process for siting of transmission lines 3. Recommendations on the tools needed to support regional planning, cost allocation, and siting efforts. List of Dialogue participants: List of Dialogue Participants: American Electric Power American Transmission Company American Wind Energy Association California ISO Calpine Corporation Cinergy Edison Electric Institute Environmental Defense Federal Energy Regulatory Commission Great River Energy International Transmission Company ISO-New England Iowa Public Utility Board Kanner & Associates Midwest ISO National Association of Regulatory Utility Commissioners National Association of State Utility Consumer Advocates National Grid Northeast Utilities PA Office of Consumer Advocates Pacific Gas & Electric Corporation Pennsylvania Public Utility Commission PJM Interconnection The Electricity Consumers Resource Council U.S. Department of Energy US Department of the Interior Van Ness Feldman Western Interstate Energy Board Wind on the Wires Wisconsin Public Service Commission Xcel Energy

  9. Transferring Data at NERSC

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Data Transferring Data Advice and Overview NERSC provides many facilities for storing data and performing analysis. However, transfering data - whether over the wide area network...

  10. NWCC Transmission Case Study III

    SciTech Connect (OSTI)

    Terry Allison, Steve Wiese

    2000-03-01T23:59:59.000Z

    OAK-B135 Transmission System Improvements for Wind Energy Development in the Upper Midwest and Great Plains: Opportunities and Obstacles. This case study set out to ascertain the validity of three assumptions from the perspectives of stakeholders involved in wind energy and transmission issues in the Upper Midwest and Great Plains. The assumptions, and the stakeholders' reactions to each, are summarized below: Assumption 1--Transmission system improvements would provide significant benefits to the electricity network and its customers. Respondents acknowledge the potential for overall system benefits in the form of reduced line losses, improved grid stability and reliability, and enhanced ability to conduct spot market transactions. They also agree that these benefits relate to specific regional needs. However, there is disagreement over the extent of other benefits such as efficiency gains and cost savings from reduced line losses. Further, environmental and community interest groups point out that none of these benefits are realized without significant financial, environmental and social costs. Assumption 2--The benefits of transmission improvements would be helpful, but not confined, to wind power. All respondents agree that wind energy could benefit from transmission system improvements. But they also acknowledge, reluctantly, in the case of environmental stakeholders, that the benefits of an improved transmission system cannot be limited to environmentally preferable forms of generation. Some environmental and community advocate respondents also feel that transmission system improvement projects can be avoided altogether through energy conservation and efficiency measures, and by substituting wind energy for fossil generation. Assumption 3--Transmission alliances among stakeholders within and external to the wind community can provide benefits in the public interest. The fractured, multi-jurisdictional governance of the regional transmission system, and the distrust and diversity of perspectives among affected stakeholders, may make the formation of multi-stakeholder alliances necessary to accomplishing transmission goals. If the wind industry and utilities want to partner with environmental and community advocate groups in supporting a transmission project, they may have to convince these groups that the project would result in a net environmental benefit. The project proponents would have to make the case that the benefits of the additional wind energy will at least offset the emissions of any additional fossil generation made possible by the transmission project, as well as offset the environmental impact of the transmission project itself.

  11. Energy Transmission and Infrastructure

    SciTech Connect (OSTI)

    Mathison, Jane

    2012-12-31T23:59:59.000Z

    The objective of Energy Transmission and Infrastructure Northern Ohio (OH) was to lay the conceptual and analytical foundation for an energy economy in northern Ohio that will: • improve the efficiency with which energy is used in the residential, commercial, industrial, agricultural, and transportation sectors for Oberlin, Ohio as a district-wide model for Congressional District OH-09; • identify the potential to deploy wind and solar technologies and the most effective configuration for the regional energy system (i.e., the ratio of distributed or centralized power generation); • analyze the potential within the district to utilize farm wastes to produce biofuels; • enhance long-term energy security by identifying ways to deploy local resources and building Ohio-based enterprises; • identify the policy, regulatory, and financial barriers impeding development of a new energy system; and • improve energy infrastructure within Congressional District OH-09. This objective of laying the foundation for a renewable energy system in Ohio was achieved through four primary areas of activity: 1. district-wide energy infrastructure assessments and alternative-energy transmission studies; 2. energy infrastructure improvement projects undertaken by American Municipal Power (AMP) affiliates in the northern Ohio communities of Elmore, Oak Harbor, and Wellington; 3. Oberlin, OH-area energy assessment initiatives; and 4. a district-wide conference held in September 2011 to disseminate year-one findings. The grant supported 17 research studies by leading energy, policy, and financial specialists, including studies on: current energy use in the district and the Oberlin area; regional potential for energy generation from renewable sources such as solar power, wind, and farm-waste; energy and transportation strategies for transitioning the City of Oberlin entirely to renewable resources and considering pedestrians, bicyclists, and public transportation as well as drivers in developing transportation policies; energy audits and efficiency studies for Oberlin-area businesses and Oberlin College; identification of barriers to residential energy efficiency and development of programming to remove these barriers; mapping of the solar-photovoltaic and wind-energy supply chains in northwest Ohio; and opportunities for vehicle sharing and collaboration among the ten organizations in Lorain County from the private, government, non-profit, and educational sectors. With non-grant funds, organizations have begun or completed projects that drew on the findings of the studies, including: creation of a residential energy-efficiency program for the Oberlin community; installation of energy-efficient lighting in Oberlin College facilities; and development by the City of Oberlin and Oberlin College of a 2.27 megawatt solar photovoltaic facility that is expected to produce 3,000 megawatt-hours of renewable energy annually, 12% of the College’s yearly power needs. Implementation of these and other projects is evidence of the economic feasibility and technical effectiveness of grant-supported studies, and additional projects are expected to advance to implementation in the coming years. The public has benefited through improved energydelivery systems and reduced energy use for street lighting in Elmore, Oak Harbor, and Wellington; new opportunities for assistance and incentives for residential energy efficiency in the Oberlin community; new opportunities for financial and energy savings through vehicle collaboration within Lorain County; and decreased reliance on fossil fuels and expanded production of renewable energy in the region. The dissemination conference and the summary report developed for the conference also benefited the public, but making the findings and recommendations of the regional studies broadly available to elected officials, city managers, educators, representatives of the private sector, and the general public.

  12. Multi-ratio transmission

    SciTech Connect (OSTI)

    Polak, J.C.

    1987-07-14T23:59:59.000Z

    A preselected multi-ratio power transmission is described comprising: input means for transmitting drive forces; output means; first, second and third friction clutch means each selectively engageable with the input means for accepting drive forces. First input gear means drivingly connects with the first friction clutch means; second input gear means drivingly connects with the second friction clutch means; third input gear means drivingly connects with the third clutch means; first output gear means drivingly connects with the first input gear means; second output gear means drivingly connects with the first and second input gear means; third output means drivingly connects between the third input gear means and the output means; and one double-acting synchronizer clutch for selectively engaging the first output gear means with the output means and alternately the second output gear means with the output means. The first friction clutch means and the one double-acting synchronizer clutch cooperates during engagement to establish two forward drive ratios between the input and output means. The second friction clutch means and the one double-acting synchronizer clutch cooperates during engagement to establish two other forward drive ratios between the input and output means. The third friction clutch means is engageable to provide another forward drive ratio between the input means and the output means; and the one double-acting synchronizer clutch is relieved of transmitting drive forces during the engagement of the third friction clutch means and being manipulable for alternate connection with either the first output gear or the second output gear while the third friction clutch means is engaged.

  13. Electrical transmission line diametrical retainer

    DOE Patents [OSTI]

    Hall, David R. (Provo, UT); Hall, Jr., H. Tracy (Provo, UT); Pixton, David (Lehi, UT); Dahlgren, Scott (Provo, UT); Sneddon, Cameron (Provo, UT); Briscoe, Michael (Lehi, UT); Fox, Joe (Spanish Fork, UT)

    2004-12-14T23:59:59.000Z

    The invention is a mechanism for retaining an electrical transmission line. In one embodiment of the invention it is a system for retaining an electrical transmission line within down hole components. In accordance with one aspect of the invention, the system includes a plurality of downhole components, such as sections of pipe in a drill string. The system also includes a coaxial cable running between the first and second end of a drill pipe, the coaxial cable having a conductive tube and a conductive core within it. The invention allows the electrical transmission line to with stand the tension and compression of drill pipe during routine drilling cycles.

  14. Midwest Transmission Workshop I Summary

    SciTech Connect (OSTI)

    Kevin Bryan

    2001-05-01T23:59:59.000Z

    OAK-B135 The meeting was opened with a review of the purposes of the workshop: (1) Present and discuss key studies and assessments of transmission upgrades, additions and related issues for the upper Midwest, including work that addresses the full range of views on these topics; (2) Understand the various transmission issues in the upper Midwest and discuss options for addressing the issues; and (3) Identify the decision makers and entities that need to play an active role if transmission issues are to be resolved, and agree on next steps for engaging these individuals and organizations through education, outreach, and information dissemination.

  15. AC and DC power transmission

    SciTech Connect (OSTI)

    Not Available

    1985-01-01T23:59:59.000Z

    The technical and economic assessment of AC and DC transmission systems; long distance transmission, cable transmission, system inter-connection, voltage support, reactive compensation, stabilisation of systems; parallel operation of DC links with AC systems; comparison between alternatives for particular schemes. Design and application equipment: design, testing and application of equipment for HVDC, series and shunt static compensated AC schemes, including associated controls. Installations: overall design of stations and conductor arrangements for HVDC, series and shunt static AC schemes including insulation co-ordination. System analysis and modelling.

  16. BPA Transmission Commercial Project Roadmap

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Commercial Project Roadmap 15-Minute Scheduling Dynamic Transfer Program NT Redispatch WECC-Bal- 002 ST Comp & Preemption ST ATC Method. PCM Monthlyweekly Implementation PCM...

  17. Flexible Transmission in the Smart Grid

    E-Print Network [OSTI]

    Hedman, Kory Walter

    2010-01-01T23:59:59.000Z

    S. S. Oren, “Smart flexible just-in-time transmission andFlexible Transmission in the Smart Grid By Kory WalterAll rights reserved. A BSTRACT Flexible Transmission in the

  18. Wireless Power Transfer

    ScienceCinema (OSTI)

    None

    2013-11-19T23:59:59.000Z

    Wireless Power Transfer is an innovative approach using magnetic resonance coupling of air core transformers designed for today's growing plug-in electric vehicle market. This technology can provide a convenient, safe and flexible means to charge electric vehicles under stationary and dynamic conditions. Plug-in Electric Vehicles (PEV) are burdened by the need for cable and plug charger, galvanic isolation of the on-board electronics, bulk and cost of this charger and the large energy storage system (ESS) packs needed. With a system where you have to physically plug in there are a number of occasions where the owner could very well forget to charge the vehicle. For stationary applications (like charging of a PHEV at home), ORNL's innovative wireless power transfer technology adds a convenience factor compared to actually plugging in which will mean that the vehicle will have a full charge every morning. Electric vehicle charging must be safe, compact and efficient in order to be convenient for customers. By reconfiguring the transformer and altering the resonance frequency, energy is transferred to the battery with lower energy losses and with fewer demands on the primary circuit by the rest of the transformer system. The ORNL discovery shows that sufficient power for the battery can be transferred from the primary to secondary circuits without significant energy losses if the operating frequency is set at 50% to 95% of the resonance frequency of the circuit. The electrical power is then transmitted to the chargeable battery, which is electrically coupled to the secondary circuit through the air core transformer. Some advantages include: Reduced energy losses during transfer of energy to the battery; A charge potential that is relatively unaffected by up to 25% misalignment of vehicle; and Other receiving components draw less power from the primary circuit. These advantages allow wireless power technology applications to expand at the workplace and beyond as the demand for EV rises. For vehicles that operate over a fixed route such as busses and shuttle vehicles, Wireless Power Transfer (WPT) means that a smaller battery pack can be used. In the traditional system, the battery pack is designed to accommodate the needs of the entire route or shift. With WPT the battery can be downsized because it can be charged when the vehicle stops on its route (a rental car shuttle bus, for example, can charge when it waits in the terminal and again when it waits at the rental car place. Thus the battery only needs enough charge to get to the next stop. This decrease in battery size means significant cost savings to electrify the vehicle. This technology enables efficient "opportunity charging stations" for predefined routes and planned stops reducing down time. Charging can occur in minutes. This improvement also eliminates the harmful emissions that occur in garages while buses are at idle during charging. In larger cities, dynamic charging offers an even greater impact utilizing existing infrastructure. As vehicles travel along busy freeways and interstate systems, wireless charging can occur while the vehicle is in motion. With this technology a vehicle essentially has unlimited electric range while using a relatively small battery pack. In-motion charging stations use vehicle sensors to alert the driver. Traveling at normal speeds, sensors establish in-motion charging. WPT transmit pads sequentially energize to the negotiated power level based on vehicle speed and its requested charging energy. Lower power when vehicle speed is slow and much higher power for faster moving vehicles. Vehicle to Infrastructure communications (V2I) coordinates WPT charging level according to on-board battery pack state-of-charge. V2I activates the roadway transmit pads placing them in standby mode and negotiates charging fee based on prevailing grid rate and vehicle energy demand. Dynamic charging would allow electricity to supply a very large fraction of the energy for the transportation sector and reduce greatly petroleum consump

  19. Wireless Power Transfer

    SciTech Connect (OSTI)

    None

    2013-07-22T23:59:59.000Z

    Wireless Power Transfer is an innovative approach using magnetic resonance coupling of air core transformers designed for today's growing plug-in electric vehicle market. This technology can provide a convenient, safe and flexible means to charge electric vehicles under stationary and dynamic conditions. Plug-in Electric Vehicles (PEV) are burdened by the need for cable and plug charger, galvanic isolation of the on-board electronics, bulk and cost of this charger and the large energy storage system (ESS) packs needed. With a system where you have to physically plug in there are a number of occasions where the owner could very well forget to charge the vehicle. For stationary applications (like charging of a PHEV at home), ORNL's innovative wireless power transfer technology adds a convenience factor compared to actually plugging in which will mean that the vehicle will have a full charge every morning. Electric vehicle charging must be safe, compact and efficient in order to be convenient for customers. By reconfiguring the transformer and altering the resonance frequency, energy is transferred to the battery with lower energy losses and with fewer demands on the primary circuit by the rest of the transformer system. The ORNL discovery shows that sufficient power for the battery can be transferred from the primary to secondary circuits without significant energy losses if the operating frequency is set at 50% to 95% of the resonance frequency of the circuit. The electrical power is then transmitted to the chargeable battery, which is electrically coupled to the secondary circuit through the air core transformer. Some advantages include: Reduced energy losses during transfer of energy to the battery; A charge potential that is relatively unaffected by up to 25% misalignment of vehicle; and Other receiving components draw less power from the primary circuit. These advantages allow wireless power technology applications to expand at the workplace and beyond as the demand for EV rises. For vehicles that operate over a fixed route such as busses and shuttle vehicles, Wireless Power Transfer (WPT) means that a smaller battery pack can be used. In the traditional system, the battery pack is designed to accommodate the needs of the entire route or shift. With WPT the battery can be downsized because it can be charged when the vehicle stops on its route (a rental car shuttle bus, for example, can charge when it waits in the terminal and again when it waits at the rental car place. Thus the battery only needs enough charge to get to the next stop. This decrease in battery size means significant cost savings to electrify the vehicle. This technology enables efficient "opportunity charging stations" for predefined routes and planned stops reducing down time. Charging can occur in minutes. This improvement also eliminates the harmful emissions that occur in garages while buses are at idle during charging. In larger cities, dynamic charging offers an even greater impact utilizing existing infrastructure. As vehicles travel along busy freeways and interstate systems, wireless charging can occur while the vehicle is in motion. With this technology a vehicle essentially has unlimited electric range while using a relatively small battery pack. In-motion charging stations use vehicle sensors to alert the driver. Traveling at normal speeds, sensors establish in-motion charging. WPT transmit pads sequentially energize to the negotiated power level based on vehicle speed and its requested charging energy. Lower power when vehicle speed is slow and much higher power for faster moving vehicles. Vehicle to Infrastructure communications (V2I) coordinates WPT charging level according to on-board battery pack state-of-charge. V2I activates the roadway transmit pads placing them in standby mode and negotiates charging fee based on prevailing grid rate and vehicle energy demand. Dynamic charging would allow electricity to supply a very large fraction of the energy for the transportation sector and reduce greatly petroleum consump

  20. Transmission Workshop | Department of Energy

    Energy Savers [EERE]

    - November 1-2, 2012 On November 1-2, 2012, the GTT presented a workshop on grid integration on the transmission system at the DoubleTree Crystal City near Washington, DC. A...

  1. Video transmission over wireless networks 

    E-Print Network [OSTI]

    Zhao, Shengjie

    2005-08-29T23:59:59.000Z

    Compressed video bitstream transmissions over wireless networks are addressed in this work. We first consider error control and power allocation for transmitting wireless video over CDMA networks in conjunction with multiuser detection. We map a...

  2. Video transmission over wireless networks

    E-Print Network [OSTI]

    Zhao, Shengjie

    2005-08-29T23:59:59.000Z

    Compressed video bitstream transmissions over wireless networks are addressed in this work. We first consider error control and power allocation for transmitting wireless video over CDMA networks in conjunction with multiuser detection. We map a...

  3. EIS-0231: Navajo Transmission Project

    Broader source: Energy.gov [DOE]

    This EIS evaluates the environmental impacts of a proposal to by Dine Power Authority, a Navajo Nation enterprise, to construct, operate, and maintain a 500 kilovolt (kV) transmission line planned...

  4. Immunology of naturally transmissible tumours

    E-Print Network [OSTI]

    Siddle, Hannah V.; Kaufman, Jim

    2014-09-04T23:59:59.000Z

    in a graft. These APCs move to the draining lymph nodes of the host, after which primed effector T cells migrate back to the graft site and target foreign cells (reviewed in (10)). Alternatively, T cells can be primed with graft-derived peptides... transmissible venereal tumour at different stages of growth. Vet Immunol Immunopathol. 1998;64(2):133-47. 57. Chandler JP, Yang TJ. Canine transmissible venereal sarcoma: distribution of T and B lymphocytes in blood, draining lymph nodes and tumours...

  5. Transmission Workshop | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn'tOriginEducationVideoStrategic|IndustrialCenter Gets PeopleTransmission Workshop Transmission

  6. Briefing Memo: Petroleum Product Transmission & Distribution...

    Energy Savers [EERE]

    Briefing Memo: Petroleum Product Transmission & Distribution Briefing Memo: Petroleum Product Transmission & Distribution Click below to download a PDF of the briefing memo....

  7. Agenda: Natural Gas: Transmission, Storage and Distribution ...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Natural Gas: Transmission, Storage and Distribution Agenda: Natural Gas: Transmission, Storage and Distribution A Public Meeting on the Quadrennial Energy Review, Hosted by the...

  8. Charge transport in micas: The kinetics of FeII/III electron...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    transport in micas: The kinetics of FeIIIII electron transfer in the octahedral sheet. Charge transport in micas: The kinetics of FeIIIII electron transfer in the octahedral...

  9. Analysis of programmable molecular electronic systems

    E-Print Network [OSTI]

    Ma, Yuefei

    2007-09-17T23:59:59.000Z

    of the programmable molecular array is performed. First, theoretical calculations for single molecules are carried out. The effect of bias voltage on the electron transmission through the molecule is reported. Next, electrical measurements are conducted...

  10. Packaging solution for VLSI electronic photonic chips

    E-Print Network [OSTI]

    Lee, Chieh-feng

    2007-01-01T23:59:59.000Z

    As the demand of information capacity grows, the adoption of optical technology will increase. The issue of resistance and capacitance is limiting the electronic transmission bandwidth while fiber optic delivers data at ...

  11. Revealing the atomic and electronic structure of a SrTiO{sub 3}/LaNiO{sub 3}/SrTiO{sub 3} heterostructure interface

    SciTech Connect (OSTI)

    Zhang, Zaoli, E-mail: zaoli.zhang@oeaw.ac.at [Erich Schmid Institute of Materials Science, Austrian Academy of Sciences, Leoben (Austria); Electron Microscopy Group for Materials Science, University of Ulm, Ulm (Germany); Soltan, S. [Max-Planck Institute for Solid State Research, D-70561 Stuttgart (Germany); Faculty of Science, Helwan University, 11795 Cairo (Egypt); Schmid, H. [INM—Leibniz-Institut für Neue Materialien, 66123 Saarbrücken (Germany); Habermeier, H.-U.; Keimer, B. [Max-Planck Institute for Solid State Research, D-70561 Stuttgart (Germany); Kaiser, U. [Electron Microscopy Group for Materials Science, University of Ulm, Ulm (Germany)

    2014-03-14T23:59:59.000Z

    The atomic structures of SrTiO{sub 3} (STO)/LaNiO{sub 3} (LNO)/STO heterostructure interfaces were investigated by spherical aberration-corrected (C{sub S}) (scanning) transmission electron microscopy. Atomic displacement and lattice distortion measurements and electron energy loss spectroscopy (EELS) were used to quantitatively analyze the distortion of the interfacial octahedra and the bond length at the interfaces. Combined with high-resolution transmission electron microscopy (HRTEM) and scanning transmission electron microscopy analyses, two distinct interfacial atomic terminating layers are unambiguously determined. Ensuing quantitative HRTEM measurements revealed that the Ni-O bond length in the interfacial octahedral is elongated at the bottom interface (–NiO{sub 2}-SrO–). Atomic displacement shows structural relaxation effects when crossing the interfaces and lattice distortions across the interface is more pronounced in LNO than in STO. The Ti/O atomic ratio, La and Ti relative atomic ratio as derived by EELS quantification indicate non-stoichiometric composition at the interfaces. Distinct fine structures of Ti-L{sub 2,3} edge and O-K edge at the bottom and top interfaces are observed. By comparison, we are able to estimate Ti valency at both interfaces. Combining the structural distortions and Ti valency, the polar discontinuity and charge transfer at the interfaces are discussed.

  12. Multi-transmission-line-beam interactive system

    SciTech Connect (OSTI)

    Figotin, Alexander; Reyes, Guillermo [Department of Mathematics, University of California at Irvine, Irvine, California 92697-3875 (United States)] [Department of Mathematics, University of California at Irvine, Irvine, California 92697-3875 (United States)

    2013-11-15T23:59:59.000Z

    We construct here a Lagrangian field formulation for a system consisting of an electron beam interacting with a slow-wave structure modeled by a possibly non-uniform multiple transmission line (MTL). In the case of a single line we recover the linear model of a traveling wave tube due to J. R. Pierce. Since a properly chosen MTL can approximate a real waveguide structure with any desired accuracy, the proposed model can be used in particular for design optimization. Furthermore, the Lagrangian formulation provides: (i) a clear identification of the mathematical source of amplification, (ii) exact expressions for the conserved energy and its flux distributions obtained from the Noether theorem. In the case of uniform MTLs we carry out an exhaustive analysis of eigenmodes and find sharp conditions on the parameters of the system to provide for amplifying regimes.

  13. July 2, 2007 1 Optimal Transmission Switching

    E-Print Network [OSTI]

    Mangasarian, Olvi L.

    d to node n. zk: binary variable indicating whether transmission line k is removed from the system limit on number of open transmission lines Manuscript received July 2, 2007. This work was supported-mail: ferris@cs.wisc.edu). Sets : Set of all transmission lines L: Set of open transmission lines in solution

  14. Transmission Lines Emulating Moving Media

    E-Print Network [OSTI]

    Vehmas, Joni; Tretyakov, Sergei

    2014-01-01T23:59:59.000Z

    In this paper, we show how the electromagnetic phenomena in moving magnetodielectric media can be emulated using artificial composite structures at rest. In particular, we introduce nonreciprocal periodically loaded transmission lines which support waves obeying the same rules as plane electromagnetic waves in moving media. Because the actual physical structure is at rest, in these transmission lines there are no fundamental limitations on the velocity values, which may take values larger than the speed of light or even complex values (considering complex amplitudes in the time-harmonic regime). An example circuit of a unit cell of a "moving" transmission line is presented and analyzed both numerically and experimentally. The special case of composite right/left handed host line is also studied numerically. Besides the fundamental interest, the study is relevant for potential applications in realizing engineered materials for various transformations of electromagnetic fields.

  15. Midwest Transmission Workshop III Summary

    SciTech Connect (OSTI)

    Kevin Bryan

    2003-03-12T23:59:59.000Z

    OAK-B135 On March 12-13, 2002, the National Wind Coordinating Committee (NWCC), in cooperation with regional stakeholders, held a two-day workshop: Planning for Electrical Transmission Needs in the Upper Midwest. The workshop was the outgrowth of an effort to develop a forum and process for consideration of transmission options that strives for equitable allocation of benefits and impacts among all affected parties. The goal of this workshop was to provide a catalyst for an enhanced, inclusive process for transmission planning with participation of and acceptance by all affected stakeholders. Participants in the meeting included representatives of state and regional regulatory agencies, utilities and power generators, the wind industry, environmental and landowner interests, and other interested parties (see Attachment A for a list of meeting participants).

  16. HEAT TRANSFER FLUIDS

    E-Print Network [OSTI]

    Lenert, Andrej

    2012-01-01T23:59:59.000Z

    The choice of heat transfer fluids has significant effects on the performance, cost, and reliability of solar thermal systems. In this chapter, we evaluate existing heat transfer fluids such as oils and molten salts based ...

  17. Transfer and characterization of silicon nanomembrane based photonic devices on flexible polyimide substrate

    E-Print Network [OSTI]

    Texas at Austin, University of

    Transfer and characterization of silicon nanomembrane based photonic devices on flexible polyimide nanomembrane based photonic devices on a Kapton polyimide flexible substrate. Compared with electronic devices

  18. Agenda - Transmission Customer Forum 40

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Dispatch Rachel Dibble 10:30-10:45 Break 10:45-11:00 Generation Interconnection Reform Update GIQ Team 11:00-11:30 Dynamic Transfer Capability Russ Mantifel 11:30-11:45...

  19. Computer controlled synchronous shifting of an automatic transmission

    DOE Patents [OSTI]

    Davis, Roy I. (9214 Abbey La., Ypsilanti, MI 48198); Patil, Prabhakar B. (10294 W. Outer Dr., Detroit, MI 48223)

    1989-01-01T23:59:59.000Z

    A multiple forward speed automatic transmission produces its lowest forward speed ratio when a hydraulic clutch and hydraulic brake are disengaged and a one-way clutch connects a ring gear to the transmission casing. Second forward speed ratio results when the hydraulic clutch is engaged to connect the ring gear to the planetary carrier of a second gear set. Reverse drive and regenerative operation result when an hydraulic brake fixes the planetary and the direction of power flow is reversed. Various sensors produce signals representing the torque at the output of the transmission or drive wheels, the speed of the power source, and the hydraulic pressure applied to a clutch and brake. A control algorithm produces input data representing a commanded upshift, a commanded downshift, a commanded transmission output torque, and commanded power source speed. A microprocessor processes the inputs and produces a response to them in accordance with the execution of a control algorithm. Output or response signals cause selective engagement and disengagement of the clutch and brake at a rate that satisfies the requirements for a short gear ratio change and smooth torque transfer between the friction elements.

  20. Computer controllable synchronous shifting of an automatic transmission

    DOE Patents [OSTI]

    Davis, R.I.; Patil, P.B.

    1989-08-08T23:59:59.000Z

    A multiple forward speed automatic transmission produces its lowest forward speed ratio when a hydraulic clutch and hydraulic brake are disengaged and a one-way clutch connects a ring gear to the transmission casing. Second forward speed ratio results when the hydraulic clutch is engaged to connect the ring gear to the planetary carrier of a second gear set. Reverse drive and regenerative operation result when an hydraulic brake fixes the planetary and the direction of power flow is reversed. Various sensors produce signals representing the torque at the output of the transmission or drive wheels, the speed of the power source, and the hydraulic pressure applied to a clutch and brake. A control algorithm produces input data representing a commanded upshift, a commanded downshift, a commanded transmission output torque, and commanded power source speed. A microprocessor processes the inputs and produces a response to them in accordance with the execution of a control algorithm. Output or response signals cause selective engagement and disengagement of the clutch and brake at a rate that satisfies the requirements for a short gear ratio change and smooth torque transfer between the friction elements. 6 figs.

  1. ITC Transmission | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are8COaBulkTransmissionSitingProcess.pdfGetecGtel JumpCounty, Texas:ITC Transmission Jump to: navigation, search Name:

  2. In Situ Transmission Electron Microscopy Observation of Microstructure...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    in a SnO2 Nanowire during Lithium Abstract: This paper reports development of a lithium-ion battery nanostructure device using a single nanowire for in-stu TEM study of the...

  3. Dynamics of soft Nanomaterials captured by transmission electron...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    water. Citation: Proetto MT, AM Rush, MP Chien, P Abellan Baeza, JP Patterson, MP Thompson, NH Olson, CE Moore, AL Rheingold, C Andolina, J Millstone, SB Howell, ND Browning,...

  4. advanced transmission electron: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Plants Websites Summary: ) establishes a framework for markets based on locational marginal pricing (LMP). The NOPR envisions a critical incentives. G iven the shortcomings of...

  5. analytical transmission electron: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Plants Websites Summary: ) establishes a framework for markets based on locational marginal pricing (LMP). The NOPR envisions a critical incentives. G iven the shortcomings of...

  6. Electronic Transmission of Prescriptions Towards Realising the Dream

    E-Print Network [OSTI]

    Kent, University of

    of one of these health care processes ­ the prescription processing system. The UK NHS came into being.W.Chadwick@salford.ac.uk Abstract: The United Kingdom National Health Service (NHS) is about to commence upon major computerisationD in the field of Internet Security. This has involved research (2000-2003) in the development of secure health

  7. In Situ Transmission Electron Microscopy Characterization of Nanomaterials 

    E-Print Network [OSTI]

    Lee, Joon Hwan 1977-

    2012-11-27T23:59:59.000Z

    .1. Overview .................................................................................................... 1 1.2. Nanomaterials ............................................................................................. 4 1.2.1. Bulk nanostructured... 1.3. Schematic diagram showing different types of nanostructured ceramic materials: a) two-phased nanocomposite material b) inter/intra-granular nanocomposite material c) micro/nanostructured material d) inter- granular nanocomposite material...

  8. In Situ Transmission Electron Microscopy Characterization of Nanomaterials

    E-Print Network [OSTI]

    Lee, Joon Hwan 1977-

    2012-11-27T23:59:59.000Z

    of deformation behavior of Al2O3-ZrO2-MgAl2O4 (AZM) bulk ceramic nanocomposites, strengthening mechanism of twins in YBa2Cu3O7-x (YBCO) thin film, work hardening event in nanocrystalline nickel and deformation of 2wt% Al doped ZnO (AZO) thin film with nanorod...

  9. THE IMPACT OF TRANSMISSION ELECTRON MICROSCOPY IN CERAMICS

    E-Print Network [OSTI]

    Thomas, Gareth

    2010-01-01T23:59:59.000Z

    Turbine Vanes", General Electric Report 74CRD040, Apriland Dr. S. Prochazka of General Electric Corporate Researcha process invented by General Electric Company20,2l in which

  10. Letters to ESEX High resolution transmission electron microscopy

    E-Print Network [OSTI]

    Dorn, Ron

    ), in south-eastern Libya (Haber- land, 1975), on gibbers (Jessup, 1960) and bedrock faces in Australia (Tratebas et al., 2004), and stone monuments (Paradise, 2005) and can act as an agent of rock art stability

  11. Amplitude Contrast High-Resolution Transmission Electron Microscopy...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    for Advanced Materials March 13, 2015 11:00AM to 12:00PM Presenter Jianguo Wen, (EMC) and (CNM) Location Building 203 Type Colloquium Series Physics Division Colloquium...

  12. Transmission Electron Microscopy Study of InN Nanorods

    E-Print Network [OSTI]

    Liliental-Weber, Z.; Li, X.; Kryliouk, Olga; Park, H.J.; Mangum, J.; Anderson, T.

    2008-01-01T23:59:59.000Z

    crystals grown on Si and GaN substrate is different. Theon c-Al 2 O 3, GaN , and Si substrates by non-catalytic,

  13. Scanning Transmission Electron Microscopy Investigations of Complex Oxides

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del Sol HomeFacebook Twitter Principal InvestigatorsSave Energy onofCNMS, SNS launch|

  14. Iran Thomas Auditorium, 8600 Environmental Transmission Electron Microscopy for Catalysis

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12 Investigation Peer Review 2012IowaFebruary 9, 2012 4:00

  15. Heat Transfer Guest Editorial

    E-Print Network [OSTI]

    Kandlikar, Satish

    Journal of Heat Transfer Guest Editorial We are indeed delighted in bringing out this special issue was showcased in diverse areas such as traditional heat and mass transfer, lab-on-chip, sensors, biomedical applica- tions, micromixers, fuel cells, and microdevices. Selected papers in the field of heat transfer

  16. Transmission needs across a fully renewable European power system

    E-Print Network [OSTI]

    Rodriguez, Rolando A; Andresen, Gorm B; Heide, Dominik; Greiner, Martin

    2013-01-01T23:59:59.000Z

    The residual load and excess power generation of 27 European countries with a 100% penetration of variable renewable energy sources are explored in order to quantify the benefit of power transmission between countries. Estimates are based on extensive weather data, which allows for modelling of hourly mismatches between the demand and renewable generation from wind and solar photovoltaics. For separated countries, balancing is required to cover around 24% of the total annual energy consumption. This number can be reduced down to 15% once all countries are networked together with uncon- strained interconnectors. The reduction represents the maximum possible benefit of transmission for the countries. The total Net Transfer Capacity of the unconstrained interconnectors is roughly twelve times larger than current values. However, constrained interconnector capacities six times larger than the current values are found to provide 97% of the maximum possible benefit of cooperation. This motivates a detailed investig...

  17. A Multiple Access Protocol for Multimedia Transmission over Wireless Networks

    E-Print Network [OSTI]

    Yu, Hong

    2012-01-01T23:59:59.000Z

    This paper develops and evaluates the performance of an advanced multiple access protocol for transmission of full complement of multimedia signals consisting of various combinations of voice, video, data, text and images over wireless networks. The protocol is called Advanced Multiple Access Protocol for Multimedia Transmission (AMAPMT) and is to be used in the Data Link Layer of the protocol stack. The principle of operation of the protocol is presented in a number of logical flow charts. The protocol grants permission to transmit to a source on the basis of a priority scheme that takes into account a time-to-live (TTL) parameter of all the transactions, selectable priorities assigned to all the sources and relevant channel state information (CSI) in this order. Performance of the protocol is evaluated in terms of quality of service parameters like packet loss ratio (PLR), mean packet transfer delay (MPTD) and throughput. Using a simulation model based on an OPNET simulation software package does the evalua...

  18. Increasing transmission loadability by the application of shunt capacitors

    SciTech Connect (OSTI)

    Palmer, R.

    1981-05-01T23:59:59.000Z

    The companies located in the eastern portion of the Pennsylvania-New Jersey-Maryland Interconnection (PJM) have installed oil-fired generation to meet strict environmental requirements. In an attempt to reduce the use of oil, PJM has been purchasing energy from systems to the west of PJM where the primary fuel is coal. These west-to-east energy transfers have increased the loading on the 500kV transmission system. The heavy loadings have resulted in voltage limitations on the 500kV system that limit flows to well below the thermal capability. Results of an analysis of this problem and recommendations for removing the voltage limitations are presented. It is primarily recommended to use shunt capacitors to supply the transmission system reactive losses.

  19. INTRAMOLECULAR CHARGE AND ENERGY TRANSFER IN MULTICHROMOPHORIC AROMATIC SYSTEMS

    SciTech Connect (OSTI)

    Edward C. Lim

    2008-09-09T23:59:59.000Z

    A concerted experimental and computational study of energy transfer in nucleic acid bases and charge transfer in dialkylaminobenzonitriles, and related electron donor-acceptor molecules, indicate that the ultrafast photoprocesses occur through three-state conical interactions involving an intermediate state of biradical character.

  20. PLM: Fast Convergence for Cumulative Layered Multicast Transmission Schemes (extended version)

    E-Print Network [OSTI]

    Legout, Arnaud

    PLM: Fast Convergence for Cumulative Layered Multicast Transmission Schemes (extended version) A the properties of a new multicast congestion control protocol (called PLM) for audio/video and file transfer. We evaluated PLM for a large variety of scenarios and show that it converges fast to the optimal link

  1. PLM: Fast Convergence for Cumulative Layered Multicast Transmission Schemes (extended version) \\Lambda

    E-Print Network [OSTI]

    Legout, Arnaud

    PLM: Fast Convergence for Cumulative Layered Multicast Transmission Schemes (extended version the properties of a new multicast congestion control protocol (called PLM) for audio/video and file transfer. We evaluated PLM for a large variety of scenarios and show that it converges fast to the optimal link

  2. Thermal Sciences The thermal sciences area involves the study of energy conversion and transmission, power

    E-Print Network [OSTI]

    New Hampshire, University of

    Thermal Sciences The thermal sciences area involves the study of energy conversion and transmission, power generation, the flow of liquids and gases, and the transfer of thermal energy (heat) by means in virtually all energy conversion devices and systems. One may think of the jet engine as a mechanical device

  3. Information Transfer Fidelity in Networks of Spins

    E-Print Network [OSTI]

    Edmond Jonckheere; Frank Langbein; Sophie Schirmer

    2014-10-05T23:59:59.000Z

    Networks of spins, or spintronic networks, are given an Information Transfer Fidelity (ITF) derived from an upper bound on the probability of transmission of the excitation from one spin to another. It is shown that this theoretical bound can be reached asymptotically in time under certain conditions. The process of achieving maximum transfer probability is given a dynamical model, the translation on the torus, and the time to reach the maximum probability is estimated using the simultaneous Diophantine approximation computationally implemented using a variant of the Lenstra-Lenstra-Lov\\'asz (LLL) algorithm. The ITF induces a prametric on the network. For a ring with homogeneous couplings, it is shown that this prametric satisfies the triangle inequality, opening up the road to an ITF geometry, which turns out to be completely different from the geometry of the physical arrangement of the spin in the spintronic device. It is shown that transfer fidelities and transfer times can be improved by means of simple controls taking the form of strong localized magnetic fields, opening up the possibility for intelligent design of spintronic networks and dynamic routing of information encoded in such networks. The approach is much more flexible than engineering the couplings to favor some transfers.

  4. The Centre for Power Transmission

    E-Print Network [OSTI]

    Burton, Geoffrey R.

    The Centre for Power Transmission and Motion Control Centre for PTMC Department of Mechanical) 1225 38-6371 Email: ptmc@bath.ac.uk Web: http://www.bath.ac.uk/ptmc/ Consultancy Project WAVE POWER SYSTEM SIMULATIONS Power take-off systems Wave power take-off systems are an exciting new development

  5. The Centre for Power Transmission

    E-Print Network [OSTI]

    Burton, Geoffrey R.

    precision and high bandwidth motion control In fluid power systems, seals are typically passive elements Bois) PTO #12;5. Modelling and Development of Low Noise Hydraulic Fluid Power Systems Hydraulic fluidThe Centre for Power Transmission and Motion Control The Centre for PTMC: analytical

  6. Power superconducting power transmission cable

    DOE Patents [OSTI]

    Ashworth, Stephen P. (Cambridge, GB)

    2003-01-01T23:59:59.000Z

    The present invention is for a compact superconducting power transmission cable operating at distribution level voltages. The superconducting cable is a conductor with a number of tapes assembled into a subconductor. These conductors are then mounted co-planarly in an elongated dielectric to produce a 3-phase cable. The arrangement increases the magnetic field parallel to the tapes thereby reducing ac losses.

  7. SLOW DEGRADATION AND ELECTRON INJECTION IN SODIUM-B ALUMINAS

    E-Print Network [OSTI]

    De Jonghe, Lutgard C.

    2013-01-01T23:59:59.000Z

    transfer of 703 XBB 804 4126 Degradation of sulfur side ofsilver staining. The degradation layer becomes more uniformMaterials Science SLOW DEGRADATION AND ELECTRON INJECTION IN

  8. Chemical Distribution and Bonding of Lithium in Intercalated Graphite: Identification with Optimized Electron Energy Loss Spectroscopy

    SciTech Connect (OSTI)

    Wang, Feng; Graetz, Jason; Moreno, M. Sergio; Ma, Chao; Wu, Lijun; Volkov, Vyacheslav; Zhu, Yimei

    2011-01-01T23:59:59.000Z

    Direct mapping of the lithium spatial distribution and the chemical state provides critical information on structure-correlated lithium transport in electrode materials for lithium batteries. Nevertheless, probing lithium, the lightest solid element in the periodic table, poses an extreme challenge with traditional X-ray or electron scattering techniques due to its weak scattering power and vulnerability to radiation damage. Here, we report nanoscale maps of the lithium spatial distribution in electrochemically lithiated graphite using electron energy loss spectroscopy in the transmission electron microscope under optimized experimental conditions. The electronic structure of the discharged graphite was obtained from the near-edge fine structure of the Li and C K-edges and ab initio calculations. A 2.7 eV chemical shift of the Li K-edge, along with changes in the density of states, reveals the ionic nature of the intercalated lithium with significant charge transfer to the graphene sheets. Direct mapping of lithium in graphite revealed nanoscale inhomogeneities (nonstoichiometric regions), which are correlated with local phase separation and structural disorder (i.e., lattice distortion and dislocations) as observed by high-resolution transmission electron microscopy. The surface solid?electrolyte interphase (SEI) layer was also imaged and determined to have a thickness of 10?50 nm, covering both edge and basal planes with LiF as its primary inorganic component. The Li K-edge spectroscopy and mapping, combined with electron microscopy-based structural analysis provide a comprehensive view of the structure-correlated lithium intercalation in graphite and of the formation of the SEI layer.

  9. Chemical Distribution and Bonding of Lithium in Intercalated Graphite: Identification with Optimized Electron Energy Loss Spectroscopy

    SciTech Connect (OSTI)

    Zhu, Y.; Wang, F.; Graetz, J.; Moreno, M.S.; Ma, C.; Wu, L.; Volkov, V.

    2011-02-01T23:59:59.000Z

    Direct mapping of the lithium spatial distribution and the chemical state provides critical information on structure-correlated lithium transport in electrode materials for lithium batteries. Nevertheless, probing lithium, the lightest solid element in the periodic table, poses an extreme challenge with traditional X-ray or electron scattering techniques due to its weak scattering power and vulnerability to radiation damage. Here, we report nanoscale maps of the lithium spatial distribution in electrochemically lithiated graphite using electron energy loss spectroscopy in the transmission electron microscope under optimized experimental conditions. The electronic structure of the discharged graphite was obtained from the near-edge fine structure of the Li and C K-edges and ab initio calculations. A 2.7 eV chemical shift of the Li K-edge, along with changes in the density of states, reveals the ionic nature of the intercalated lithium with significant charge transfer to the graphene sheets. Direct mapping of lithium in graphite revealed nanoscale inhomogeneities (nonstoichiometric regions), which are correlated with local phase separation and structural disorder (i.e., lattice distortion and dislocations) as observed by high-resolution transmission electron microscopy. The surface solid-electrolyte interphase (SEI) layer was also imaged and determined to have a thickness of 10-50 nm, covering both edge and basal planes with LiF as its primary inorganic component. The Li K-edge spectroscopy and mapping, combined with electron microscopy-based structural analysis provide a comprehensive view of the structure-correlated lithium intercalation in graphite and of the formation of the SEI layer.

  10. The Cost of Transmission for Wind Energy: A Review of Transmission Planning Studies

    E-Print Network [OSTI]

    Mills, Andrew D.

    2009-01-01T23:59:59.000Z

    analysis of the difference in transmission costs for wind andour meta-analysis on the unit cost of transmission for windanalysis of these studies reveals considerable differences in the implied unit cost of transmission for wind.

  11. NREL: Transmission Grid Integration - Transmission Planning and Analysis

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible for Renewable Energy: Grid IntegrationReportTransmission Planning and Analysis Thumbnail

  12. Energy transfer kinetics in oxy-fluoride glass and glass-ceramics doped with rare-earth ions

    SciTech Connect (OSTI)

    Sontakke, Atul D.; Annapurna, K. [Glass Science and Technology Section, CSIR-Central Glass and Ceramic Research Institute, 196, Raja S. C. Mullick Road, Kolkata - 700 032 (India)

    2012-07-01T23:59:59.000Z

    An investigation of donor-acceptor energy transfer kinetics in dual rare earths doped precursor oxy-fluoride glass and its glass-ceramics containing NaYF{sub 4} nano-crystals is reported here, using three different donor-acceptor ion combinations such as Nd-Yb, Yb-Dy, and Nd-Dy. The precipitation of NaYF{sub 4} nano-crystals in host glass matrix under controlled post heat treatment of precursor oxy-fluoride glasses has been confirmed from XRD, FESEM, and transmission electron microscope (TEM) analysis. Further, the incorporation of dopant ions inside fluoride nano-crystals has been established through optical absorption and TEM-EDX analysis. The noticed decreasing trend in donor to acceptor energy transfer efficiency from precursor glass to glass-ceramics in all three combinations have been explained based on the structural rearrangements that occurred during the heat treatment process. The reduced coupling phonon energy for the dopant ions due to fluoride environment and its influence on the overall phonon assisted contribution in energy transfer process has been illustrated. Additionally, realization of a correlated distribution of dopant ions causing clustering inside nano-crystals has also been reported.

  13. The Cost of Transmission for Wind Energy: A Review of Transmission Planning Studies

    E-Print Network [OSTI]

    Mills, Andrew D.

    2009-01-01T23:59:59.000Z

    2007. “Inclusion of Wind in the MISO Transmission Expansionhttp://www.jcspstudy.org/ Midwest ISO (MISO). 2007. Midwest+Planning Midwest ISO (MISO). 2003. Midwest Transmission

  14. A CRITICAL REVIEW OF WIND TRANSMISSION COST ESTIMATES FROM MAJOR TRANSMISSION PLANNING EFFORTS

    E-Print Network [OSTI]

    Mills, Andrew; Wiser, Ryan; Porter, Kevin

    2007-01-01T23:59:59.000Z

    A CRITICAL REVIEW OF WIND TRANSMISSION COST ESTIMATES FROMof establishing a wind transmission cost adder with respectthat involve wind and divide the cost by the relative share

  15. A CRITICAL REVIEW OF WIND TRANSMISSION COST ESTIMATES FROM MAJOR TRANSMISSION PLANNING EFFORTS

    E-Print Network [OSTI]

    Mills, Andrew; Wiser, Ryan; Porter, Kevin

    2007-01-01T23:59:59.000Z

    in calculating the unit cost of wind energy transmissionimpacts of the cost of transmission for wind energy. Only inj = Transmission cost per unit of wind energy weighted by

  16. Impact of electron irradiation on electron holographic potentiometry

    SciTech Connect (OSTI)

    Park, J. B.; Niermann, T.; Lehmann, M. [Technische Universität Berlin, Institut für Optik und Atomare Physik, Straße des 17. Juni 135, 10623 Berlin (Germany); Berger, D. [Technische Universität Berlin, Zentraleinrichtung für Elektronenmikroskopie, Strae des 17. Juni 135, 10623 Berlin (Germany); Knauer, A.; Weyers, M. [Ferdinand-Braun-Institut, Leibnitz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Str. 4, 12489 Berlin (Germany); Koslow, I.; Kneissl, M. [Ferdinand-Braun-Institut, Leibnitz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Str. 4, 12489 Berlin (Germany); Technische Universität Berlin, Institut für Festkörperphysik, Hardenbergstr. 36, 10623 Berlin (Germany)

    2014-09-01T23:59:59.000Z

    While electron holography in the transmission electron microscope offers the possibility to measure maps of the electrostatic potential of semiconductors down to nanometer dimensions, these measurements are known to underestimate the absolute value of the potential, especially in GaN. We have varied the dose rates of electron irradiation over several orders of magnitude and observed strong variations of the holographically detected voltages. Overall, the results indicate that the electron beam generates electrical currents within the specimens primarily by the photovoltaic effect and due to secondary electron emission. These currents have to be considered for a quantitative interpretation of electron holographic measurements, as their negligence contributes to large parts in the observed discrepancy between the measured and expected potential values in GaN.

  17. Transmission

    Office of Environmental Management (EM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33Frequently AskedEnergyIssuesEnergy SolarRadioactiveITransactional7AMelissa Howell |

  18. Transmission

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del SolStrengthening a solidSynthesisAppliances » Data ManagementTransit

  19. Fuel transfer system

    DOE Patents [OSTI]

    Townsend, H.E.; Barbanti, G.

    1994-03-01T23:59:59.000Z

    A nuclear fuel bundle fuel transfer system includes a transfer pool containing water at a level above a reactor core. A fuel transfer machine therein includes a carriage disposed in the transfer pool and under the water for transporting fuel bundles. The carriage is selectively movable through the water in the transfer pool and individual fuel bundles are carried vertically in the carriage. In a preferred embodiment, a first movable bridge is disposed over an upper pool containing the reactor core, and a second movable bridge is disposed over a fuel storage pool, with the transfer pool being disposed therebetween. A fuel bundle may be moved by the first bridge from the reactor core and loaded into the carriage which transports the fuel bundle to the second bridge which picks up the fuel bundle and carries it to the fuel storage pool. 6 figures.

  20. Midwest Transmission Workshop II Summary

    SciTech Connect (OSTI)

    Kevin Bryan

    2002-12-05T23:59:59.000Z

    OAK-B135 After introductions of all participants, Abby Arnold, RESOLVE, reviewed the purpose of the meeting and the agenda. The purpose of the workshop was to share the results of the Midwest Independent System Operator (MISO) scenario development for wind and other fuel sources and the corresponding implications for transmission throughout the MISO control area. The workshop agenda is included in Attachment A.

  1. NREL: Transmission Grid Integration - Webinars

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible for Renewable Energy: Grid IntegrationReportTransmission Planning and Analysis

  2. NREL: Transmission Grid Integration - Webmaster

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible for Renewable Energy: Grid IntegrationReportTransmission Planning and AnalysisWebmaster

  3. Grand Coulee Transmission Line Replacement Project

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    by the Bureau of Reclamation to design and construct six new 500-kV overhead transmission lines at Grand Coulee Dam. BPA will replace the existing underground transmission...

  4. Sandia National Laboratories: energy transmission and distribution

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    grid relies on power transmission from the production source-be it a coal-fired plant, solar array, or wind farm-to the consumer. Long-distance transmission results in...

  5. Sandia National Laboratories: transmission grid integration

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    grid relies on power transmission from the production source-be it a coal-fired plant, solar array, or wind farm-to the consumer. Long-distance transmission results in...

  6. Florida Electric Transmission Line Siting Act (Florida)

    Broader source: Energy.gov [DOE]

    The Transmission Line Siting Act (TLSA) is the state’s centralized process for licensing electrical transmission lines which; (a) are 230 kV or larger; (b) cross a county line; and, (c) are 15...

  7. Transmission Issues and Power Exchanges in Texas

    E-Print Network [OSTI]

    Hughes, H. L.

    on the transmission owning utilities by several parties, primary distribution cooperatives, cogenerators, and large industrial customers, to grant wider access to the system. This pressure is coming at a time when transmission lines are becoming increasingly difficult...

  8. Electron radiography

    DOE Patents [OSTI]

    Merrill, Frank E.; Morris, Christopher

    2005-05-17T23:59:59.000Z

    A system capable of performing radiography using a beam of electrons. Diffuser means receive a beam of electrons and diffuse the electrons before they enter first matching quadrupoles where the diffused electrons are focused prior to the diffused electrons entering an object. First imaging quadrupoles receive the focused diffused electrons after the focused diffused electrons have been scattered by the object for focusing the scattered electrons. Collimator means receive the scattered electrons and remove scattered electrons that have scattered to large angles. Second imaging quadrupoles receive the collimated scattered electrons and refocus the collimated scattered electrons and map the focused collimated scattered electrons to transverse locations on an image plane representative of the electrons' positions in the object.

  9. Coiled transmission line pulse generators

    DOE Patents [OSTI]

    McDonald, Kenneth Fox (Columbia, MO)

    2010-11-09T23:59:59.000Z

    Methods and apparatus are provided for fabricating and constructing solid dielectric "Coiled Transmission Line" pulse generators in radial or axial coiled geometries. The pour and cure fabrication process enables a wide variety of geometries and form factors. The volume between the conductors is filled with liquid blends of monomers, polymers, oligomers, and/or cross-linkers and dielectric powders; and then cured to form high field strength and high dielectric constant solid dielectric transmission lines that intrinsically produce ideal rectangular high voltage pulses when charged and switched into matched impedance loads. Voltage levels may be increased by Marx and/or Blumlein principles incorporating spark gap or, preferentially, solid state switches (such as optically triggered thyristors) which produce reliable, high repetition rate operation. Moreover, these Marxed pulse generators can be DC charged and do not require additional pulse forming circuitry, pulse forming lines, transformers, or an a high voltage spark gap output switch. The apparatus accommodates a wide range of voltages, impedances, pulse durations, pulse repetition rates, and duty cycles. The resulting mobile or flight platform friendly cylindrical geometric configuration is much more compact, light-weight, and robust than conventional linear geometries, or pulse generators constructed from conventional components. Installing additional circuitry may accommodate optional pulse shape improvements. The Coiled Transmission Lines can also be connected in parallel to decrease the impedance, or in series to increase the pulse length.

  10. HIGEE Mass Transfer

    E-Print Network [OSTI]

    Mohr, R. J.; Fowler, R.

    HIGEE MASS TRANSFER R.J. Mohr and R. Fowler GLITSCH, INC. Dallas, Texas ABSTRACT Distillation, absorption, and gas stripping have traditionally been performed in tall columns utilizing trays or packing. Columns perform satisfactorily... transfer system which utilizes a rotating bed of packing to achieve high efficiency separations, and consequent reduction in size and weight. INTRODUCTION HIGEE is probably one of the most interesting developments in mass transfer equipment made...

  11. Articles about Grid Integration and Transmission

    Broader source: Energy.gov [DOE]

    Stories about grid integration and transmission featured by the U.S. Department of Energy (DOE) Wind Program.

  12. California - Establishing Transmission Project Review Streamlining...

    Open Energy Info (EERE)

    LibraryAdd to library PermittingRegulatory Guidance - Supplemental Material: California - Establishing Transmission Project Review Streamlining DirectivesPermitting...

  13. Discontinuities in transmission lines and wave guides

    E-Print Network [OSTI]

    Mathis, Harold Fletcher

    1952-01-01T23:59:59.000Z

    DISCONTINUITIES IN TRANSMISSION LINES AND WAVEGUIDES H. F. MATHIS DISCONTINUITIES IN TRANSMISSION LINES AND liVAVNGUIDBS A Thesis By Harola Fletcher htathis Approved as to style and content by: Chairman of Committee DISCONTINUITIES... Subject. Electrical Engineering COHERENT S PAGE I Introduct ion, II Dl. scontlnuit les in Transmission Lines 2 1. Some Seneral char aeter 1 st 1 ca of the transmission lines. . . , . . . , ~ 5 2 ~ 2. Types of dlscontlnuitles ln transmls- sl...

  14. MATERIALS TRANSFER AGREEMENT

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    MTAXX-XXX 1 MATERIAL TRANSFER AGREEMENT for Manufacturing Demonstration Facility and Carbon Fiber Technology Facility In order for the RECIPIENT to obtain materials, the RECIPIENT...

  15. Technology Transfer Reports

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Advanced Research Projects Agency-Energy (ARPA-E) Oil & Gas Technology Transfer Initiatives USEFUL LINKS Association of University Technology Managers (AUTM) Federal Laboratory...

  16. Bus transfer analysis

    SciTech Connect (OSTI)

    Weronick, R.; Hassan, I.D. [Raytheon Engineers and Constructors, Lyndhurst, NJ (United States)

    1996-11-01T23:59:59.000Z

    This paper discusses bus transfer schemes and the methodology used in modeling and analysis. Due to the unavailability of generic acceptance criteria, simulations were performed to analyze the actual fast bus transfer operations at four operating nuclear power generating stations. Sample simulation results illustrating the transient variations in motors currents and torques are included. The analyses were performed to ensure that motors and other rotating parts are not subjected to excessive or accumulated stresses caused by bus transfer operations. A summary of the experience gained in the process of performing this work and suggested bus transfer acceptance criteria are also presented.

  17. Facility Survey & Transfer

    Broader source: Energy.gov [DOE]

    As DOE facilities become excess, many that are radioactively and/or chemically contaminated will become candidate for transfer to DOE-EM for deactivation and decommissioning.

  18. Synthesis and Characterization of Four Consecutive Members of the Five-Member [Fe6S8(PEt3)6]n+ (n ) 0-4) Cluster Electron Transfer Series

    E-Print Network [OSTI]

    2)6]2+ and H2S, to contain face-capped octahedral Fe6S8 cores, and to be components of the five,17 Chemically reversible addition or removal of electrons from clusters can result in measurable changes in core

  19. Proton transfer from the bulk to the bound ubiquinone QB of the reaction center in

    E-Print Network [OSTI]

    Steinhoff, Heinz-Jürgen

    Proton transfer from the bulk to the bound ubiquinone QB of the reaction center in chromatophores, 1999) The mechanism of proton transfer from the bulk into the mem- brane protein interior was studied is accompanied by proton trapping. We used kinetic spec- troscopy to measure (i) the electron transfer to QB (at

  20. Transmission Dr. Sandra Cruz-Pol

    E-Print Network [OSTI]

    Cruz-Pol, Sandra L.

    Transmission Lines Dr. Sandra Cruz-Pol ECE Dept. UPRM Exercise 11.3 n A 40-m long TL has Vg=15 Vrms to electric circuits! cmc kmc GHz Hz 15000,000,2000/ 000,560/ 2 60 == == Transmission Lines I. TL parameters-wave transformer ¨ Slotted line ¨ Single stub VI. Microstrips Transmission Lines (TL) n TL have two conductors

  1. Smart Grid Application of Optimal Transmission Switching

    E-Print Network [OSTI]

    Ferris, Michael C.

    ;6 Introduction continued Electric Transmission Network Flow Problem Optimal Power Flow (OPF) AlternatingSmart Grid Application of Optimal Transmission Switching By, Kory W. Hedman, et al.* University (Professor, UC Berkeley) #12;2 Motivation Co-optimize transmission topology and generation dispatch

  2. A Distributed System for Cooperative MIMO Transmissions

    E-Print Network [OSTI]

    Kalyanaraman, Shivkumar

    a distributed system for facilitating cooperative MIMO transmissions in networks without multiple antenna diversity can be leveraged at the network, link or physical layers to provide energy efficient transmissions for reliable low-power transmissions. The rest of this paper is organized as follows: the proposed system

  3. > MEPS06 Preprint Version Transmission Loss

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    .phulpin@supelec.fr Abstract - In the deregulated electrical power system, the allocation of transmission losses is becoming a key issue. The electric transmission power system is more and more constrained due to the increasing electrical power system, the allocation of transmission losses is becoming a key issue. The electric

  4. Electron Irradiation Induced Changes of the Electrical Transport Properties of Graphene 

    E-Print Network [OSTI]

    Woo, Sung Oh

    2014-08-06T23:59:59.000Z

    This research investigates the effect of electron irradiation on transport properties in graphene Field Effect Transistor (FET) devices. Upon irradiation, graphene is doped with electrons and adsorbs molecules by transfer of accumulated electrons...

  5. Electron Irradiation Induced Changes of the Electrical Transport Properties of Graphene

    E-Print Network [OSTI]

    Woo, Sung Oh

    2014-08-06T23:59:59.000Z

    This research investigates the effect of electron irradiation on transport properties in graphene Field Effect Transistor (FET) devices. Upon irradiation, graphene is doped with electrons and adsorbs molecules by transfer of accumulated electrons...

  6. Integrated Transmission and Distribution Control

    SciTech Connect (OSTI)

    Kalsi, Karanjit; Fuller, Jason C.; Tuffner, Francis K.; Lian, Jianming; Zhang, Wei; Marinovici, Laurentiu D.; Fisher, Andrew R.; Chassin, Forrest S.; Hauer, Matthew L.

    2013-01-16T23:59:59.000Z

    Distributed, generation, demand response, distributed storage, smart appliances, electric vehicles and renewable energy resources are expected to play a key part in the transformation of the American power system. Control, coordination and compensation of these smart grid assets are inherently interlinked. Advanced control strategies to warrant large-scale penetration of distributed smart grid assets do not currently exist. While many of the smart grid technologies proposed involve assets being deployed at the distribution level, most of the significant benefits accrue at the transmission level. The development of advanced smart grid simulation tools, such as GridLAB-D, has led to a dramatic improvement in the models of smart grid assets available for design and evaluation of smart grid technology. However, one of the main challenges to quantifying the benefits of smart grid assets at the transmission level is the lack of tools and framework for integrating transmission and distribution technologies into a single simulation environment. Furthermore, given the size and complexity of the distribution system, it is crucial to be able to represent the behavior of distributed smart grid assets using reduced-order controllable models and to analyze their impacts on the bulk power system in terms of stability and reliability. The objectives of the project were to: • Develop a simulation environment for integrating transmission and distribution control, • Construct reduced-order controllable models for smart grid assets at the distribution level, • Design and validate closed-loop control strategies for distributed smart grid assets, and • Demonstrate impact of integrating thousands of smart grid assets under closed-loop control demand response strategies on the transmission system. More specifically, GridLAB-D, a distribution system tool, and PowerWorld, a transmission planning tool, are integrated into a single simulation environment. The integrated environment allows the load flow interactions between the bulk power system and end-use loads to be explicitly modeled. Power system interactions are modeled down to time intervals as short as 1-second. Another practical issue is that the size and complexity of typical distribution systems makes direct integration with transmission models computationally intractable. Hence, the focus of the next main task is to develop reduced-order controllable models for some of the smart grid assets. In particular, HVAC units, which are a type of Thermostatically Controlled Loads (TCLs), are considered. The reduced-order modeling approach can be extended to other smart grid assets, like water heaters, PVs and PHEVs. Closed-loop control strategies are designed for a population of HVAC units under realistic conditions. The proposed load controller is fully responsive and achieves the control objective without sacrificing the end-use performance. Finally, using the T&D simulation platform, the benefits to the bulk power system are demonstrated by controlling smart grid assets under different demand response closed-loop control strategies.

  7. 1 Copyright 2012 by ASME Proceedings of the ASME 2012 Summer Heat Transfer Conference

    E-Print Network [OSTI]

    Bahrami, Majid

    1 Copyright © 2012 by ASME Proceedings of the ASME 2012 Summer Heat Transfer Conference HT2012 July. INTRODUCTION Passive cooling is a widely preferred method for electronic and power electronic devices since, #12;2 Copyright © 2012 by ASME is convective heat transfer coefficient and is thermal conductivity

  8. Fact #850: December 8, 2014 Automatic Transmissions have closed...

    Broader source: Energy.gov (indexed) [DOE]

    Historically, manual transmissions have delivered better fuel economy than automatic transmissions. However, improvements in the efficiency of automatic transmissions have closed...

  9. Comments of New England Electric Transmission Corporation on...

    Broader source: Energy.gov (indexed) [DOE]

    out of time and comments of New England Electric Transmission Corporation, New England Hydro-Transmission Electric Company, Inc. and New England Hydro-Transmission Corporation and...

  10. Planning considerations for the intermountain HVDC transmission system

    SciTech Connect (OSTI)

    Lee, R.L.; Beshir, M.J.; Gee, J.H.

    1986-01-01T23:59:59.000Z

    Planning of an HVDC transmission system embedded into an existing ac network may require unique control and converter equipment capability in order to satisfy stability requirements of the network. The planning and design of the Intermountain Power Project HVDC transmission system are based on unique control performance features for power transfers during terminal ac faults, rapid power recovery following fault clearing and utilization of exceptionally high transient overload capability of 2 per unit during the post-fault period to maintain system stability. The Department, in its efforts to meet the Western Systems Coordinating Council's (WSCC) reliability criteria, developed and incorporated into its HVDC specifications very rigorous reliability and availability requirements. One objective of this project was to attain the unusually low bipolar converter system outage frequency goal of one outage in five years to achieve a bipole performance rating equivalent to two ac circuits of similar capability. The reliability goals of this project have provided one of the impetus for revisions to the WSCC Reliability Criteria for System Design. The reliability goals and other features adopted for the Intermountain HVDC transmission system are discussed in this paper and study results are included to demonstrate the effectiveness of various controls implemented as stability enhancement techniques.

  11. The Cost of Transmission for Wind Energy in the United States: A Review of Transmission Planning Studies.

    E-Print Network [OSTI]

    Wiser, Ryan

    2014-01-01T23:59:59.000Z

    on U. S . Wind Power Installation, Cost, and Performance30% wind penetration. Wind transmission costs in the severalof Transmission ($/kW-wind) Unit Cost of Transmission ($/

  12. Automated manual transmission mode selection controller

    DOE Patents [OSTI]

    Lawrie, Robert E. (Whitmore Lake, MI)

    1999-11-09T23:59:59.000Z

    A powertrain system for a hybrid vehicle. The hybrid vehicle includes a heat engine, such as a diesel engine, and an electric machine, which operates as both an electric motor and an alternator, to power the vehicle. The hybrid vehicle also includes a manual-style transmission configured to operate as an automatic transmission from the perspective of the driver. The engine and the electric machine drive an input shaft which in turn drives an output shaft of the transmission. In addition to driving the transmission, the electric machine regulates the speed of the input shaft in order to synchronize the input shaft during either an upshift or downshift of the transmission by either decreasing or increasing the speed of the input shaft. When decreasing the speed of the input shaft, the electric motor functions as an alternator to produce electrical energy which may be stored by a storage device. Operation of the transmission is controlled by a transmission controller which receives input signals and generates output signals to control shift and clutch motors to effect smooth launch, upshift shifts, and downshifts of the transmission, so that the transmission functions substantially as an automatic transmission from the perspective of the driver, while internally substantially functioning as a manual transmission.

  13. Automated manual transmission shift sequence controller

    DOE Patents [OSTI]

    Lawrie, Robert E. (Whitmore Lake, MI); Reed, Richard G. (Royal Oak, MI); Rausen, David J. (Denver, CO)

    2000-02-01T23:59:59.000Z

    A powertrain system for a hybrid vehicle. The hybrid vehicle includes a heat engine, such as a diesel engine, and an electric machine, which operates as both, an electric motor and an alternator, to power the vehicle. The hybrid vehicle also includes a manual-style transmission configured to operate as an automatic transmission from the perspective of the driver. The engine and the electric machine drive an input shaft which in turn drives an output shaft of the transmission. In addition to driving the transmission, the electric machine regulates the speed of the input shaft in order to synchronize the input shaft during either an upshift or downshift of the transmission by either decreasing or increasing the speed of the input shaft. When decreasing the speed of the input shaft, the electric motor functions as an alternator to produce electrical energy which may be stored by a storage device. Operation of the transmission is controlled by a transmission controller which receives input signals and generates output signals to control shift and clutch motors to effect smooth launch, upshift shifts, and downshifts of the transmission, so that the transmission functions substantially as an automatic transmission from the perspective of the driver, while internally substantially functioning as a manual transmission.

  14. Reprint of: Regulation of photosynthetic electron transport , Jean-David Rochaix

    E-Print Network [OSTI]

    Halazonetis, Thanos

    , the two light reactions operate in series whereby electrons extracted from water by PSII are transferred Keywords: Electron transport Linear electron ow Cyclic electron ow Photosystem II Photosystem I Light-harvesting with the oxidation of water followed by electron ow along the electron transport chain and concomitant pumping

  15. Pulse shaping with transmission lines

    DOE Patents [OSTI]

    Wilcox, Russell B. (Oakland, CA)

    1987-01-01T23:59:59.000Z

    A method and apparatus for forming shaped voltage pulses uses passive reflection from a transmission line with nonuniform impedance. The impedance of the reflecting line varies with length in accordance with the desired pulse shape. A high voltage input pulse is transmitted to the reflecting line. A reflected pulse is produced having the desired shape and is transmitted by pulse removal means to a load. Light activated photoconductive switches made of silicon can be utilized. The pulse shaper can be used to drive a Pockels cell to produce shaped optical pulses.

  16. Pulse shaping with transmission lines

    DOE Patents [OSTI]

    Wilcox, R.B.

    1985-08-15T23:59:59.000Z

    A method and apparatus for forming shaped voltage pulses uses passive reflection from a transmission line with nonuniform impedance. The impedance of the reflecting line varies with length in accordance with the desired pulse shape. A high voltage input pulse is transmitted to the reflecting line. A reflected pulse is produced having the desired shape and is transmitted by pulse removal means to a load. Light activated photoconductive switches made of silicon can be utilized. The pulse shaper can be used to drive a Pockels cell to produce shaped optical pulses.

  17. Sandia Energy - Transmission Grid Integration

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del Sol Home Distribution GridDocumentsInstituteThree-DimensionalTransmission Grid

  18. Transmission Workshop | Department of Energy

    Energy Savers [EERE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are being directedAnnual Siteof Energy 2, 2015 - JanuaryTankToledo, Ohio,Transmission

  19. POSITION DESCRIPTION 2012 TRANSFER MENTOR

    E-Print Network [OSTI]

    POSITION DESCRIPTION 2012 TRANSFER MENTOR TRANSFER MENTOR AS A STAFF MEMBER Thank you for your interest in the Transfer Mentor position with Orientation and Transition Programs' (OTP) Transfer Mentoring Program. The Transfer Mentor (TM) is a member of the Orientation and Transition Programs' staff

  20. Resolution Limits of Electron-Beam Lithography toward the Atomic Scale

    E-Print Network [OSTI]

    Zhang, Lihua

    We investigated electron-beam lithography with an aberration-corrected scanning transmission electron microscope. We achieved 2 nm isolated feature size and 5 nm half-pitch in hydrogen silsesquioxane resist. We also analyzed ...