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1

Probing Ultrafast Solvation Dynamics with High Repetition-Rate...  

NLE Websites -- All DOE Office Websites (Extended Search)

Highlights rss feed Probing Ultrafast Solvation Dynamics with High Repetition-Rate LaserX-ray Methodologies FEBRUARY 11, 2012 Bookmark and Share X-ray absorption, emission...

2

Ultrafast Dynamics of Pyrrolidinium Ionic Liquids  

NLE Websites -- All DOE Office Websites (Extended Search)

Ultrafast Dynamics of Pyrrolidinium Cation Ionic Liquids Hideaki Shirota, Alison M. Funston, James F. Wishart, Edward W. Castner, Jr. J. Chem. Phys. 122, 184512 (2005). Find paper...

3

Intermolecular Dynamics, Interactions and Solvation in Ionic Liquids  

NLE Websites -- All DOE Office Websites (Extended Search)

Dynamics, Interactions and Solvation in Ionic Liquids Dynamics, Interactions and Solvation in Ionic Liquids Edward W. Castner, Jr., James F. Wishart, and Hideaki Shirota Acc. Chem. Res. 40, 1217-1227 (2007). [Find paper at ACS Publications] Abstract: Ionic liquids can simultaneously assume multiple solvent roles, because they are strongly polar and polarizable solvents and binary solutions and frequently contain very hydrophobic components. When the cation and anion functional groups are tuned appropriately, ionic liquids can be used as designer solvents for a broad range of applications. In this Account, we discuss our spectroscopic studies on the intermolecular interactions, dynamics, solvation, transport, and friction in ionic liquids, as compared with information obtained from macroscopic experiments including viscometry

4

Dynamic Protonation Equilibrium of Solvated Acetic Acid  

Science Conference Proceedings (OSTI)

For the first time, the dynamic protonation equilibrium between an amino acid side chain analogue and bulk water as well as the diffusion properties of the excess proton were successfully reproduced through unbiased computer simulations. During a 50 ns Q-HOP MD simulation, two different regimes of proton transfer were observed. Extended phases of frequent proton swapping between acetic acid and nearby water were separated by phases where the proton freely diffuses in the simulation box until it is captured again by acetic acid. The pKa of acetic acid was calculated around 3.0 based on the relative population of protonated and deprotonated states and the diffusion coefficient of excess proton was computed from the average mean squared displacement in the simulation. Both calculated values agree well with the experimental measurements.

Gu, Wei; Frigato, Tomaso; Straatsma, TP; Helms, Volkhard H.

2007-04-13T23:59:59.000Z

5

Ultrafast photoinduced electron transfer reactions in supramolecular arrays: Studies of electronic coupling and solvation  

DOE Green Energy (OSTI)

Research in our laboratory focuses on developing supramolecular arrays that produce long-lived charge separation by limiting the electronic coupling between the separated charges, and on the role of solvation in determining the rates and energetics of photoinitiated electron transfer reactions. Arrays have been developed that closely mimic the electronic coupling that was observed only for long-lived radical pairs produced in photosynthetic glassy solids. A series of 36 fixed-distance donor-acceptor molecules using porphyrin donors, triptycene spacers, and 9 different acceptors has been prepared; these are used to probe the dependence of photoinduced charge separation rates on free energy of reaction as a function of solvent both in liquid and solid solution. Data were obtained on rates of charge separation in dioxane, MTHF, butyronitrile, toluene, chlorobenzene, and benzonitrile.

Wasielewski, M.R.; Wiederrecht, G.P.; Svec, W.A.

1993-01-01T23:59:59.000Z

6

Ultrafast photoinduced electron transfer reactions in supramolecular arrays: Studies of electronic coupling and solvation  

DOE Green Energy (OSTI)

Research in our laboratory focuses on developing supramolecular arrays that produce long-lived charge separation by limiting the electronic coupling between the separated charges, and on the role of solvation in determining the rates and energetics of photoinitiated electron transfer reactions. Arrays have been developed that closely mimic the electronic coupling that was observed only for long-lived radical pairs produced in photosynthetic glassy solids. A series of 36 fixed-distance donor-acceptor molecules using porphyrin donors, triptycene spacers, and 9 different acceptors has been prepared; these are used to probe the dependence of photoinduced charge separation rates on free energy of reaction as a function of solvent both in liquid and solid solution. Data were obtained on rates of charge separation in dioxane, MTHF, butyronitrile, toluene, chlorobenzene, and benzonitrile.

Wasielewski, M.R.; Wiederrecht, G.P.; Svec, W.A.

1993-05-01T23:59:59.000Z

7

Ultrafast Core-Hole Induced Dynamics in Water  

NLE Websites -- All DOE Office Websites (Extended Search)

Ultrafast Core-Hole Induced Ultrafast Core-Hole Induced Dynamics in Water Ultrafast Core-Hole Induced Dynamics in Water Print Wednesday, 22 February 2006 00:00 A thorough understanding of the chemical processes that are initiated when radiation interacts with aqueous systems is essential for many diverse fields, from condensed matter physics to medicine to environmental science. An incoming photon with enough energy to produce a core hole in a water molecule sets off motions that can affect bonding configurations, which in turn affect subsequent chemical-reaction pathways. However, it is a fundamental challenge for the radiation chemistry community to unravel the early time dynamics of electronically excited states in water because their short (femtosecond) time scales are difficult to access directly with pump-probe measurements. Using a combination of isotope substitution experiments and molecular dynamics simulations, researchers from Sweden, Germany, and the U.S. have shown that the ultrafast (0- to 10-fs) dissociation dynamics of liquid water can be successfully probed with x-ray emission spectroscopy.

8

Ultrafast Core-Hole Induced Dynamics in Water  

NLE Websites -- All DOE Office Websites (Extended Search)

Ultrafast Core-Hole Induced Dynamics in Water Print Ultrafast Core-Hole Induced Dynamics in Water Print A thorough understanding of the chemical processes that are initiated when radiation interacts with aqueous systems is essential for many diverse fields, from condensed matter physics to medicine to environmental science. An incoming photon with enough energy to produce a core hole in a water molecule sets off motions that can affect bonding configurations, which in turn affect subsequent chemical-reaction pathways. However, it is a fundamental challenge for the radiation chemistry community to unravel the early time dynamics of electronically excited states in water because their short (femtosecond) time scales are difficult to access directly with pump-probe measurements. Using a combination of isotope substitution experiments and molecular dynamics simulations, researchers from Sweden, Germany, and the U.S. have shown that the ultrafast (0- to 10-fs) dissociation dynamics of liquid water can be successfully probed with x-ray emission spectroscopy.

9

Ultrafast Core-Hole Induced Dynamics in Water  

NLE Websites -- All DOE Office Websites (Extended Search)

Ultrafast Core-Hole Induced Dynamics in Water Print Ultrafast Core-Hole Induced Dynamics in Water Print A thorough understanding of the chemical processes that are initiated when radiation interacts with aqueous systems is essential for many diverse fields, from condensed matter physics to medicine to environmental science. An incoming photon with enough energy to produce a core hole in a water molecule sets off motions that can affect bonding configurations, which in turn affect subsequent chemical-reaction pathways. However, it is a fundamental challenge for the radiation chemistry community to unravel the early time dynamics of electronically excited states in water because their short (femtosecond) time scales are difficult to access directly with pump-probe measurements. Using a combination of isotope substitution experiments and molecular dynamics simulations, researchers from Sweden, Germany, and the U.S. have shown that the ultrafast (0- to 10-fs) dissociation dynamics of liquid water can be successfully probed with x-ray emission spectroscopy.

10

Ultrafast Core-Hole Induced Dynamics in Water  

NLE Websites -- All DOE Office Websites (Extended Search)

Ultrafast Core-Hole Induced Dynamics in Water Print Ultrafast Core-Hole Induced Dynamics in Water Print A thorough understanding of the chemical processes that are initiated when radiation interacts with aqueous systems is essential for many diverse fields, from condensed matter physics to medicine to environmental science. An incoming photon with enough energy to produce a core hole in a water molecule sets off motions that can affect bonding configurations, which in turn affect subsequent chemical-reaction pathways. However, it is a fundamental challenge for the radiation chemistry community to unravel the early time dynamics of electronically excited states in water because their short (femtosecond) time scales are difficult to access directly with pump-probe measurements. Using a combination of isotope substitution experiments and molecular dynamics simulations, researchers from Sweden, Germany, and the U.S. have shown that the ultrafast (0- to 10-fs) dissociation dynamics of liquid water can be successfully probed with x-ray emission spectroscopy.

11

Ultrafast dynamic ellipsometry and spectroscopy of laser shocked materials  

SciTech Connect

Shock waves create extreme states of matter with very high pressures, temperatures, and volumetric compressions, at an exceedingly rapid rate of change. We review how to use a beamsplitter and a note card to turn a typical chirp pulse amplified femtosecond laser system into an ultrafast shock dynamics machine. Open scientific questions that can be addressed with such an apparatus are described. We report on the development of several single shot time resolved diagnostics needed to answer these questions. These single shot diagnostics are expected to be broadly applicable to other types of laser ablation experiments. Experimental results measured from shocked material dynamics of several systems are detailed. Finally, we report on progress towards using transient absorption as a measure of electronic excitation and coherent Raman as a picosecond probe of temperature in shock compressed condensed matter.

Mcgrane, Shawn David [Los Alamos National Laboratory; Bolme, Cindy B [Los Alamos National Laboratory; Whitley, Von H [Los Alamos National Laboratory; Moore, David S [Los Alamos National Laboratory

2010-01-01T23:59:59.000Z

12

Optical Nonlinearities and Ultrafast Carrier Dynamics in Semiconductor Quantum Dots  

SciTech Connect

Low-dimensional semiconductors have attracted great interest due to the potential for tailoring their linear and nonlinear optical properties over a wide-range. Semiconductor nanocrystals (NC's) represent a class of quasi-zero-dimensional objects or quantum dots. Due to quantum cordhement and a large surface-to-volume ratio, the linear and nonlinear optical properties, and the carrier dynamics in NC's are significantly different horn those in bulk materials. napping at surface states can lead to a fast depopulation of quantized states, accompanied by charge separation and generation of local fields which significantly modifies the nonlinear optical response in NC's. 3D carrier confinement also has a drastic effect on the energy relaxation dynamics. In strongly confined NC's, the energy-level spacing can greatly exceed typical phonon energies. This has been expected to significantly inhibit phonon-related mechanisms for energy losses, an effect referred to as a phonon bottleneck. It has been suggested recently that the phonon bottleneck in 3D-confined systems can be removed due to enhanced role of Auger-type interactions. In this paper we report femtosecond (fs) studies of ultrafast optical nonlinearities, and energy relaxation and trap ping dynamics in three types of quantum-dot systems: semiconductor NC/glass composites made by high temperature precipitation, ion-implanted NC's, and colloidal NC'S. Comparison of ultrafast data for different samples allows us to separate effects being intrinsic to quantum dots from those related to lattice imperfections and interface properties.

Klimov, V.; McBranch, D.; Schwarz, C.

1998-08-10T23:59:59.000Z

13

Solvation Thermodynamics  

Science Conference Proceedings (OSTI)

... a consistent, high-quality compilation of solvation thermodynamics data for a ... the solvation process to permit solvation thermodynamic quantities to ...

2013-02-26T23:59:59.000Z

14

Free energy of solvation from molecular dynamics simulation applying Voronoi-Delaunay triangulation to the cavity creation  

Science Conference Proceedings (OSTI)

The free energy of solvation for a large number of representative solutes in various solvents has been calculated from the polarizable continuum model coupled to molecular dynamics computer simulation. A new algorithm based on the Voronoi-Delaunay triangulation of atom-atom contact points between the solute and the solvent molecules is presented for the estimation of the solvent-accessible surface surrounding the solute. The volume of the inscribed cavity is used to rescale the cavitational contribution to the solvation free energy for each atom of the solute atom within scaled particle theory. The computation of the electrostaticfree energy of solvation is performed using the Voronoi-Delaunay surface around the solute as the boundary for the polarizable continuum model. Additional short-range contributions to the solvation free energy are included directly from the solute-solvent force field for the van der Waals-type interactions. Calculated solvation free energies for neutral molecules dissolved in benzene

Paulo F. B. Goncalves; Hubert Stassen

2005-01-01T23:59:59.000Z

15

Ultrafast time dynamics studies of periodic lattices with free electron laser radiation  

Science Conference Proceedings (OSTI)

It has been proposed that radiation from free electron laser (FEL) at Hamburg (FLASH) can be used for ultrafast time-resolved x-ray diffraction experiments based on the near-infrared (NIR) pump/FEL probe scheme. Here, investigation probing the ultrafast structural dynamics of periodic nano-crystalline organic matter (silver behenate) with such a scheme is reported. Excitation with a femtosecond NIR laser leads to an ultrafast lattice modification which time evolution has been studied through the scattering of vacuum ultraviolet FEL pulses. The found effect last for 6 ps and underpins the possibility for studying nanoperiodic dynamics down to the FEL source time resolution. Furthermore, the possibility of extending the use of silver behenate (AgBh) as a wavelength and temporal calibration tool for experiments with soft x-ray/FEL sources is suggested.

Quevedo, W.; Busse, G.; Hallmann, J.; More, R.; Petri, M.; Rajkovic, I. [Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Goettingen (Germany); Krasniqi, F.; Rudenko, A. [Max Planck Advanced Study Group at CFEL, Notkestrasse 85, 22607 Hamburg (Germany); Tschentscher, T. [European XFEL GmbH, Albert-Einstein-Ring 19, 22671 Hamburg (Germany); Stojanovic, N.; Duesterer, S.; Treusch, R.; Tolkiehn, M. [HASYLAB at DESY, Notkestrasse 85, 22607 Hamburg (Germany); Techert, S. [Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Goettingen (Germany); Max Planck Advanced Study Group at CFEL, Notkestrasse 85, 22607 Hamburg (Germany)

2012-11-01T23:59:59.000Z

16

Coherent exciton dynamics in supramolecular light-harvesting nanotubes revealed by ultrafast quantum process tomography  

E-Print Network (OSTI)

Long-lived exciton coherences have been recently observed in photosynthetic complexes via ultrafast spectroscopy, opening exciting possibilities for the study and design of coherent exciton transport. Yet, ambiguity in the spectroscopic signals has led to arguments for interpreting them in terms of the exciton dynamics, demanding more stringent tests. We propose a novel strategy, Quantum Process Tomography (QPT) for ultrafast spectroscopy, to reconstruct the evolving quantum state of excitons in double-walled supramolecular light-harvesting nanotubes at room temperature. The protocol calls for eight transient grating experiments with varied pulse spectra. Our analysis reveals unidirectional energy transfer from the outer to the inner wall excitons, absence of nonsecular processes, and an unexpected coherence between those two states lasting about 150 femtoseconds, indicating weak electronic coupling between the walls. Our work constitutes the first experimental QPT in a 'warm' and complex system, and provides an elegant scheme to maximize information from ultrafast spectroscopy experiments.

Joel Yuen-Zhou; Dylan H. Arias; Dorthe M. Eisele; Colby P. Steiner; Jacob J. Krich; Moungi Bawendi; Keith A. Nelson; Alán Aspuru-Guzik

2013-08-19T23:59:59.000Z

17

Structural aspects of the solvation shell of lysine and acetylated lysine: A Car-Parrinello and classical molecular dynamics investigation  

Science Conference Proceedings (OSTI)

Lysine acetylation is a post-translational modification, which modulates the affinity of protein-protein and/or protein-DNA complexes. Its crucial role as a switch in signaling pathways highlights the relevance of charged chemical groups in determining the interactions between water and biomolecules. A great effort has been recently devoted to assess the reliability of classical molecular dynamics simulations in describing the solvation properties of charged moieties. In the spirit of these investigations, we performed classical and Car-Parrinello molecular dynamics simulations on lysine and acetylated-lysine in aqueous solution. A comparative analysis between the two computational schemes is presented with a focus on the first solvation shell of the charged groups. An accurate structural analysis unveils subtle, yet statistically significant, differences which are discussed in connection to the significant electronic density charge transfer occurring between the solute and the surrounding water molecules.

Carnevale, V. [Department of Chemistry, Center for Molecular Modeling, University of Pennsylvania, Philadelphia, Pennsylvania, 19104-6323 (United States); Raugei, S. [International School for Advanced Studies (SISSA) and CNR-INFM Democritos, Via Beirut 2, Trieste I-34014 Italy, Trieste (Italy)

2009-12-14T23:59:59.000Z

18

Ultrafast Dynamic Metallization of Dielectric Nanofilms by Strong Single-Cycle Optical Fields  

E-Print Network (OSTI)

We predict a dynamic metallization effect where an ultrafast (single-cycle) optical pulse with a field less or on the order of 1 V/Angstrom causes plasmonic metal-like behavior of a dielectric film with a few-nm thickness. This manifests itself in plasmonic oscillations of polarization and a significant population of the conduction band evolving on a femtosecond time scale. These phenomena are due a combination of both adiabatic (reversible) and diabatic (for practical purposes irreversible) pathways.

Durach, Maxim; Kling, Matthias F; Stockman, Mark I

2011-01-01T23:59:59.000Z

19

Ultrafast dynamics of Coulomb correlated excitons in GaAs quantum wells  

Science Conference Proceedings (OSTI)

The author measures the transient nonlinear optical response of room temperature excitons in gallium arsenide quantum wells via multi-wave mixing experiments. The dynamics of the resonantly excited excitons is directly reflected by the ultrafast decay of the induced nonlinear polarization, which radiates the detected multi-wave mixing signal. She characterizes this ultrafast coherent emission in both amplitude and phase, using time- and frequency-domain measurement techniques, to better understand the role of Coulomb correlation in these systems. To interpret the experimental results, the nonlinear optical response of a dense medium is calculated using a model including Coulomb interaction. She contributes three new elements to previous theoretical and experimental studies of these systems. First, surpassing traditional time-integrated measurements, she temporally resolves the amplitude of the ultrafast coherent emission. Second, in addition to measuring the third-order four-wave mixing signal, she also investigates the fifth-order six-wave mixing response. Third, she characterizes the ultrafast phase dynamics of the nonlinear emission using interferometric techniques with an unprecedented resolution of approximately 140 attoseconds. The author finds that effects arising from Coulomb correlation dominate the nonlinear optical response when the density of excitons falls below 3 {times} 10{sup 11} cm{sup {minus}2}, the saturation density. These signatures of Coulomb correlation are investigated for increasing excitation density to gradually screen the interactions and test the validity of the model for dense media. The results are found to be qualitatively consistent with both the predictions of the model and with numerical solutions to the semiconductor Bloch equations. Importantly, the results also indicate current experimental and theoretical limitations, which should be addressed in future research.

Mycek, M.A. [Univ. of California, Berkeley, CA (United States). Dept. of Physics]|[Lawrence Berkeley National Lab., CA (United States). Materials Sciences Div.

1995-12-01T23:59:59.000Z

20

Ultrafast Core-Hole Induced Dynamics in Water  

NLE Websites -- All DOE Office Websites (Extended Search)

molecular level, you will find a surprisingly turbulent, dynamic universe. The water molecules constantly form and break bonds under the influence of several weak interactions,...

Note: This page contains sample records for the topic "ultrafast solvation dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Ultrafast structural dynamics and isomerization in Rydberg-exited Quadricyclane  

SciTech Connect

The quadricyclane - norbornadiene system is an important model for the isomerization dynamics between highly strained molecules. In a breakthrough observation for a polyatomic molecular system of that complexity, we follow the photoionization from Rydberg states in the time-domain to derive a measure for the time-dependent structural dynamics and the time-evolving structural dispersion even while the molecule is crossing electronic surfaces. The photoexcitation to the 3s and 3p Rydberg states deposits significant amounts of energy into vibrational motions. We observe the formation and evolution of the vibrational wavepacket on the Rydberg surface and the internal conversion from the 3p Rydberg states to the 3s state. In that state, quadricyclane isomerizes to norbornadiene with a time constant of {tau}{sub 2} = 136(45) fs. The lifetime of the 3p Rydberg state in quadricyclane is {tau}{sub 1} = 320(31) and the lifetime of the 3s Rydberg state in norbornadiene is {tau}{sub 3} = 394(32).

Rudakov, Fedor M [ORNL

2012-01-01T23:59:59.000Z

22

Ultrafast intramolecular relaxation dynamics of Mg- and Zn-bacteriochlorophyll a  

SciTech Connect

Ultrafast excited-state dynamics of the photosynthetic pigment (Mg-)bacteriochlorophyll a and its Zn-substituted form were investigated by steady-state absorption/fluorescence and femtosecond pump-probe spectroscopic measurements. The obtained steady-state absorption and fluorescence spectra of bacteriochlorophyll a in solution showed that the central metal compound significantly affects the energy of the Q{sub x} state, but has almost no effect on the Q{sub y} state. Photo-induced absorption spectra were recorded upon excitation of Mg- and Zn-bacteriochlorophyll a into either their Q{sub x} or Q{sub y} state. By comparing the kinetic traces of transient absorption, ground-state beaching, and stimulated emission after excitation to the Q{sub x} or Q{sub y} state, we showed that the Q{sub x} state was substantially incorporated in the ultrafast excited-state dynamics of bacteriochlorophyll a. Based on these observations, the lifetime of the Q{sub x} state was determined to be 50 and 70 fs for Mg- and Zn-bacteriochlorophyll a, respectively, indicating that the lifetime was influenced by the central metal atom due to the change of the energy gap between the Q{sub x} and Q{sub y} states.

Kosumi, Daisuke [Osaka City University Advanced Research Institute for Natural Science and Technology, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 (Japan); CREST/JST, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); Nakagawa, Katsunori; Sakai, Shunsuke [Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Nagaoka, Yuya; Maruta, Satoshi; Sugisaki, Mitsuru [CREST/JST, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); Department of Physics, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 (Japan); Dewa, Takehisa [Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); PRESTO/JST, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); Nango, Mamoru [The Osaka City University Advanced Research Institute for Natural Science and Technology, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 (Japan); CREST/JST, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Hashimoto, Hideki [The Osaka City University Advanced Research Institute for Natural Science and Technology, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 (Japan); CREST/JST, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); Department of Physics, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 (Japan)

2013-07-21T23:59:59.000Z

23

Synthesis, Characterization, and Ultrafast Dynamics of Metal, Metal Oxide, and Semiconductor Nanomaterials  

E-Print Network (OSTI)

EM) and PL Measurements……….472 Femtosecond Laser System andlaser System and Transient Absorption Measurements UltrafastSystem: Ultrafast transient bleach measurements were conducted using an amplified femtosecond Ti-sapphire laser

Wheeler, Damon Andreas

2013-01-01T23:59:59.000Z

24

Structure and energetics of solvated ferrous and ferric ions: Car-Parrinello molecular dynamics in the DFT+U formalism  

E-Print Network (OSTI)

We implemented a rotationally-invariant Hubbard U extension to density-functional theory in the Car-Parrinello molecular dynamics framework, with the goal of bringing the accuracy of the DFT+U approach to finite-temperature simulations, especially for liquids or solids containing transition-metal ions. First, we studied the effects on the Hubbard U on the static equilibrium structure of the hexa-aqua ferrous and ferric ions, and the inner-sphere reorganization energy for the electron-transfer reaction between aqueous ferrous and ferric ions. It is found that the reorganization energy is increased, mostly as a result of the Fe-O distance elongation in the hexa-aqua ferrous ion. Second, we performed a first-principles molecular dynamics study of the solvation structure of the two aqueous ferrous and ferric ions. The Hubbard term is found to change the Fe-O radial distribution function for the ferrous ion, while having a negligible effect on the aqueous ferric ion. Moreover, the frequencies of vibrations between Fe and oxygen atoms in the first-solvation shell are shown to be unaffected by the Hubbard corrections for both ferrous and ferric ions.

P. H. -L. Sit; Matteo Cococcioni; Nicola Marzari

2007-01-12T23:59:59.000Z

25

Ultrafast X-Ray Spectroscopy as a Probe of Nonequilibrium Dynamics in  

NLE Websites -- All DOE Office Websites (Extended Search)

The Electronic Origin of Photoinduced Strain The Electronic Origin of Photoinduced Strain Modifying Proteins to Combat Disease Higher Temperature at the Earth's Core Clues about Rheumatoid Arthritis Damage Science Highlights Archives: 2013 | 2012 | 2011 | 2010 2009 | 2008 | 2007 | 2006 2005 | 2004 | 2003 | 2002 2001 | 2000 | 1998 | Subscribe to APS Science Highlights rss feed Ultrafast X-Ray Spectroscopy as a Probe of Nonequilibrium Dynamics in Ruthenium Complexes FEBRUARY 8, 2013 Bookmark and Share Copyright © 2012 Elsevier B.V. All rights reserved. Exciting the atoms or molecules of a substance via the use of visible light, or photoexcitation, can play a significant role in a range of energy-conversion processes, such as natural photosynthesis (oxygen from water) and manmade solar cells (electricity from sunlight). But a better

26

Development of laser-plasma diagnostics using ultrafast atomic-scale dynamics. 96-ERD-046 final report  

Science Conference Proceedings (OSTI)

Ultrashort laser pulse systems allow examination of intense, ultrafast laser-plasma interactions. More specifically, intense laser irradiation can induce short xuv/x-ray bursts from the surface of condensed phase targets. Ultrafast xuv/x-ray detection is needed to understand laser-plasma interactions in this dynamic regime. Support of the Stockpile Stewardship and Management Program requires this critical understanding. Our effort here has been to extend understanding of atomic-scale dynamics in such environments with the goal of developing next generation ultrafast xuv/x-ray diagnostics where the sensors will be the atoms and ions themselves and the time resolution will approach that of the induced atomic transitions ({approx} a few femtoseconds). Pivotal contributions to the rapidly developing field of highly nonperturbative interactions of ultrashort pulse lasers with atoms/ions have been made at this laboratory. In the visible/infrared wavelength regions the temporal and spectral content of ultrashort laser pulses are now reliably monitored within a single pulse using frequency resolved optical gating (FROG) which is based on rapid nonlinear optical processes such as the Kerr effect. New applications of this basic concept are still being developed. Corresponding detection for the xuv/x-ray wavelengths does not exist and is urgently needed in many laboratory programs. The FROG technique cannot be applied in the xuv/x-ray region. Current x-ray streak camera technology is limited to {approx}0.5 picosecond resolution.

Bolton, P.R.; Kulander, K.C. [Lawrence Livermore National Lab., CA (United States); Boreham, B.W. [Central Queensland Univ., Rockhampton, QLD (Australia). Dept. of Applied Physics

1997-03-01T23:59:59.000Z

27

Biomolecular electrostatics and solvation: a computational perspective  

Science Conference Proceedings (OSTI)

An understanding of molecular interactions is essential for insight into biological systems at the molecular scale. Among the various components of molecular interactions, electrostatics are of special importance because of their long-range nature and their influence on polar or charged molecules, including water, aqueous ions, proteins, nucleic acids, carbohydrates, and membrane lipids. In particular, robust models of electrostatic interactions are essential for understanding the solvation properties of biomolecules and the effects of solvation upon biomolecular folding, binding, enzyme catalysis and dynamics. Electrostatics, therefore, are of central importance to understanding biomolecular structure and modeling interactions within and among biological molecules. This review discusses the solvation of biomolecules with a computational biophysics view towards describing the phenomenon. While our main focus lies on the computational aspect of the models, we summarize the common characteristics of biomolecular solvation (e.g., solvent structure, polarization, ion binding, and nonpolar behavior) in order to provide reasonable backgrounds to understand the solvation models.

Ren, Pengyu; Chun, Jaehun; Thomas, Dennis G.; Schnieders, Michael; Marucho, Marcelo; Zhang, Jiajing; Baker, Nathan A.

2012-11-01T23:59:59.000Z

28

Ultrafast dynamics of liquid water: Frequency fluctuations of the OH stretch and the HOH bend  

SciTech Connect

Frequency fluctuations of the OH stretch and the HOH bend in liquid water are reported from the third-order response function evaluated using the TTM3-F potential for water. The simulated two-dimensional infrared (IR) spectra of the OH stretch are similar to previously reported theoretical results. The present study suggests that the frequency fluctuation of the HOH bend is faster than that of the OH stretch. The ultrafast loss of the frequency correlation of the HOH bend is due to the strong couplings with the OH stretch as well as the intermolecular hydrogen bond bend.

Imoto, Sho; Xantheas, Sotiris S.; Saito, Shinji

2013-07-28T23:59:59.000Z

29

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

SciTech Connect

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.

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

2012-07-25T23:59:59.000Z

30

Advances in Computational Solvation Thermodynamics.  

E-Print Network (OSTI)

??The aim of this thesis is to develop improved methods for calculating the free energy, entropy and enthalpy of solvation from molecular simulations. Solvation thermodynamics… (more)

Wyczalkowski, Matthew

2009-01-01T23:59:59.000Z

31

Synthesis, Characterization, and Ultrafast Dynamics of Metal, Metal Oxide, and Semiconductor Nanomaterials  

E-Print Network (OSTI)

Dynamics in Type II CdSe/CdTe Tetrapod Heteronanostructures.Hole Dynamics in Core/Shell CdSe/CdS Dot/Rod Nanocrystals.to Rock Salt Transformation in CdSe Nanocrystals. 1994, 265,

Wheeler, Damon Andreas

2013-01-01T23:59:59.000Z

32

Magnetooptical Kerr effect measurements of ultrafast spin dynamics in cobalt nanodots  

Science Conference Proceedings (OSTI)

We present our magnetooptical Kerr effect (MOKE) studies on picosecond spin dynamics in closely spaced rectangular Co dots with sizes ranging from 2×6 ?m2 down to 100 × 300 nm2 under in-plane, picosecond, ... Keywords: Coherent spin dynamics, Kerr effect, femtosecond optical pulses, magnetic nanodots, magnetooptics, picosecond magnetic transients, spintronics

D. Wang; A. Verevkin; R. Sobolewski; R. Adam; A. van der Hart; R. Franchy

2005-07-01T23:59:59.000Z

33

Dynamics of water and aqueous protons studied using ultrafast multi-dimensional infrared spectroscopy  

E-Print Network (OSTI)

Liquid water consists of a highly dynamic network of hydrogen bonds, which evolves on timescales ranging from tens of femtoseconds to a few picoseconds. The fast structural evolution of water's hydrogen bond network is at ...

Ramasesha, Krupa

2013-01-01T23:59:59.000Z

34

Single shot ultrafast dynamic ellipsometry (UDE) of laser-driven shocks in single crystal explosives  

SciTech Connect

We report on the first experiments to measure states in shocked energetic single crystals with dynamic ellipsometry. We demonstrate that these ellipsometric techniques can produce reasonable Hugoniot values using small amounts of crystalline RDX and PETN. Pressures, particle velocities and shock velocities obtained using shocked ellipsometry are comparable to those found using gas-gun flyer plates and molecular dynamics calculations. The adaptation of the technique from uniform thin films of polymers to thick non-perfect crystalline materials was a significant achievement. Correct sample preparation proved to be a crucial component. Through trial and error, we were able to resolve polishing issues, sample quality problems, birefringence effects and mounting difficulties that were not encountered using thin polymer films.

Whitley, Von H [Los Alamos National Laboratory; Mcgrane, Shawn D [Los Alamos National Laboratory; Moore, David S [Los Alamos National Laboratory; Eakins, Dan E [Los Alamos National Laboratory; Bolme, Cindy A [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

35

Ultrafast probing of ejection dynamics of Rydberg atoms and molecular fragments from electronically excited helium nanodroplets  

SciTech Connect

The ejection dynamics of Rydberg atoms and molecular fragments from electronically excited helium nanodroplets are studied with time-resolved extreme ultraviolet ion imaging spectroscopy. At excitation energies of 23.6 {+-} 0.2 eV, Rydberg atoms in n= 3 and n= 4 states are ejected on different time scales and with significantly different kinetic energy distributions. Specifically, n= 3 Rydberg atoms are ejected with kinetic energies as high as 0.85 eV, but their appearance is delayed by approximately 200 fs. In contrast, n= 4 Rydberg atoms appear within the time resolution of the experiment with considerably lower kinetic energies. Major features in the Rydberg atom kinetic energy distributions for both principal quantum numbers can be described within a simple elastic scattering model of localized perturbed atomic Rydberg atoms that are expelled from the droplet due to their repulsive interaction with the surrounding helium bath. Time-dependent kinetic energy distributions of He{sub 2}{sup +} and He{sub 3}{sup +} ions are presented that support the formation of molecular ions in an indirect droplet ionization process and the ejection of neutral Rydberg dimers on a similar time scale as the n= 3 Rydberg atoms.

Buenermann, Oliver; Kornilov, Oleg; Neumark, Daniel M. [Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Department of Chemistry, University of California, Berkeley, California 94720 (United States); Haxton, Daniel J.; Gessner, Oliver [Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Leone, Stephen R. [Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Department of Chemistry, University of California, Berkeley, California 94720 (United States); Department of Physics, University of California, Berkeley, California 94720 (United States)

2012-12-07T23:59:59.000Z

36

A New Material for Warm-White LEDs | Advanced Photon Source  

NLE Websites -- All DOE Office Websites (Extended Search)

Probing Ultrafast Solvation Dynamics with High Repetition-Rate LaserX-ray Methodologies Ultrafast X-Ray Spectroscopy as a Probe of Nonequilibrium Dynamics in Ruthenium Complexes...

37

Ultrafast nonlinear optical properties of passive and active semiconductor devices  

E-Print Network (OSTI)

Nonlinear optical properties and ultrafast carrier dynamics of slab-coupled optical waveguide amplifiers, silicon nanowaveguides, and III-V semiconductor saturable Bragg reflectors are studied. The limits imposed by two ...

Motamedi, Ali Reza

2011-01-01T23:59:59.000Z

38

Excited state carrier dynamics in CdS{sub x}Se{sub 1-x} semisconductor alloys as studied by ultrafast fluorescence spectroscopy  

Science Conference Proceedings (OSTI)

This dissertation discusses studies of the electron-hole pair dynamics of CdS{sub x}Se{sub 1-x} semiconductor alloys for the entire compositional range from x = 1 to x = 0 as examined by the ultrafast fluorescence techniques of time correlated single photon counting and fluorescence upconversion. Specifically, samples with x = 1, .75, .5, .25, and 0 were studied each at a spread of wavelengths about its respective emission maximum which varies according to {lambda} = 718nm - 210x nm. The decays of these samples were found to obey a Kohlrausch distribution, exp [(t/{tau}){sup {beta}}], with the exponent 3 in the range .5-.7 for the alloys. These results are in agreement with those expected for localization due to local potential variations resulting from the random distribution of sulfur and selenium atoms on the element VI A sub-lattice. This localization can be understood in terms of Anderson localization of the holes in states whose energy distribution tails into the forbidden energy band-gap. Because these states have energy dependent lifetimes, the carriers can decay via many parallel channels. This distribution of channels is the ultimate source of the Kohlrausch form of the fluorescence decays.

Gadd, S.E.

1995-08-01T23:59:59.000Z

39

Ultrafast Accelerators for Pulse Radiolysis  

NLE Websites -- All DOE Office Websites (Extended Search)

in this area agreed that it would be useful to organize a specialist's conference on ultrafast accelerators for pulse radiolysis, to discuss the common experiences and problems...

40

Ultrafast supercontinuum fiber-laser based pump-probe scanning MOKE microscope for the investigation of electron spin dynamics in semiconductors at cryogenic temperatures with picosecond time and micrometer spatial resolution  

E-Print Network (OSTI)

We describe a two-color pump-probe scanning magneto-optical Kerr effect (MOKE) microscope which we have developed to investigate electron spin phenomena in semiconductors at cryogenic temperatures with picosecond time and micrometer spatial resolution. The key innovation of our microscope is the usage of an ultrafast `white light' supercontinuum fiber-laser source which provides access to the whole visible and near-infrared spectral range. Our Kerr microscope allows for the independent selection of the excitation and detection energy while avoiding the necessity to synchronize the pulse trains of two separate picosecond laser systems. The ability to independently tune the pump and probe wavelength enables the investigation of the influence of excitation energy on the optically induced electron spin dynamics in semiconductors. We demonstrate picosecond real-space imaging of the diffusive expansion of optically excited electron spin packets in a (110) GaAs quantum well sample to illustrate the capabilities of t...

Henn, T; Ossau, W; Molenkamp, L W; Biermann, K; Santos, P V

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "ultrafast solvation dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Plasmonic enhanced ultrafast switch.  

Science Conference Proceedings (OSTI)

Ultrafast electronic switches fabricated from defective material have been used for several decades in order to produce picosecond electrical transients and TeraHertz radiation. Due to the ultrashort recombination time in the photoconductor materials used, these switches are inefficient and are ultimately limited by the amount of optical power that can be applied to the switch before self-destruction. The goal of this work is to create ultrafast (sub-picosecond response) photoconductive switches on GaAs that are enhanced through plasmonic coupling structures. Here, the plasmonic coupler primarily plays the role of being a radiation condenser which will cause carriers to be generated adjacent to metallic electrodes where they can more efficiently be collected.

Subramania,Ganapathi Subramanian; Reno, John Louis; Passmore, Brandon Scott; Harris, Tom.; Shaner, Eric Arthur; Barrick, Todd A.

2009-09-01T23:59:59.000Z

42

Ultrafast electron beam imaging of femtosecond laser-induced plasma  

NLE Websites -- All DOE Office Websites (Extended Search)

Ultrafast electron beam imaging of femtosecond laser-induced plasma Ultrafast electron beam imaging of femtosecond laser-induced plasma dynamics Title Ultrafast electron beam imaging of femtosecond laser-induced plasma dynamics Publication Type Journal Article Year of Publication 2010 Authors Li, Junjie, Xuan Wang, Zhaoyang Chen, Richard Clinite, Samuel S. Mao, Pengfei Zhu, Zhengming Sheng, Jie Zhang, and Jianming Cao Journal Journal of Applied Physics Volume 107 Issue 8 Date Published 03/2010 Keywords copper, electron beam applications, high-speed optical techniques, laser ablation, plasma diagnostics, plasma production by laser Abstract Plasma dynamics in the early stage of laser ablation of a copper target are investigated in real time by making ultrafast electron shadow images and electron deflectometry measurements. These complementary techniques provide both a global view and a local perspective of the associated transient electric field and charge expansion dynamics. The results reveal that the charge cloud above the target surface is composed predominantly of thermally ejected electrons and that it is self-expanding, with a fast front-layer speed exceeding 107 m/s. The average electric field strength of the charge cloud induced by a pump fluence of 2.2 J/cm2 is estimated to be ∼ 2.4×105 V/m.

43

Lithium Ion Solvation: Amine and Unsaturated Hydrocarbon Solvates of Lithium Hexamethyldisilazide (LiHMDS)  

E-Print Network (OSTI)

Lithium Ion Solvation: Amine and Unsaturated Hydrocarbon Solvates of Lithium Hexamethyldisilazide, and 13C NMR spectroscopic studies of 6Li-15N labeled lithium hexamethyldisilazide ([6Li,15N]- Li ligand structure and lithium amide aggregation state is a complex and sensitive function of amine alkyl

Collum, David B.

44

Ultrafast scanning probe microscopy  

DOE Patents (OSTI)

An ultrafast scanning probe microscopy method for achieving subpicosecond-temporal resolution and submicron-spatial resolution of an observation sample. In one embodiment of the present claimed invention, a single short optical pulse is generated and is split into first and second pulses. One of the pulses is delayed using variable time delay means. The first pulse is then directed at an observation sample located proximate to the probe of a scanning probe microscope. The scanning probe microscope produces probe-sample signals indicative of the response of the probe to characteristics of the sample. The second pulse is used to modulate the probe of the scanning probe microscope. The time delay between the first and second pulses is then varied. The probe-sample response signal is recorded at each of the various time delays created between the first and second pulses. The probe-sample response signal is then plotted as a function of time delay to produce a cross-correlation of the probe sample response. In so doing, the present invention provides simultaneous subpicosecond-temporal resolution and submicron-spatial resolution of the sample.

Weiss, Shimon (El Cerrito, CA); Chemla, Daniel S. (Kensington, CA); Ogletree, D. Frank (El Cerrito, CA); Botkin, David (San Francisco, CA)

1995-01-01T23:59:59.000Z

45

Ultrafast scanning probe microscopy  

DOE Patents (OSTI)

An ultrafast scanning probe microscopy method is described for achieving subpicosecond-temporal resolution and submicron-spatial resolution of an observation sample. In one embodiment of the present claimed invention, a single short optical pulse is generated and is split into first and second pulses. One of the pulses is delayed using variable time delay means. The first pulse is then directed at an observation sample located proximate to the probe of a scanning probe microscope. The scanning probe microscope produces probe-sample signals indicative of the response of the probe to characteristics of the sample. The second pulse is used to modulate the probe of the scanning probe microscope. The time delay between the first and second pulses is then varied. The probe-sample response signal is recorded at each of the various time delays created between the first and second pulses. The probe-sample response signal is then plotted as a function of time delay to produce a cross-correlation of the probe sample response. In so doing, the present invention provides simultaneous subpicosecond-temporal resolution and submicron-spatial resolution of the sample. 6 Figs.

Weiss, S.; Chemla, D.S.; Ogletree, D.F.; Botkin, D.

1995-05-16T23:59:59.000Z

46

Fast Molecular Solvation Energetics and Forces Computation  

Science Conference Proceedings (OSTI)

The total free energy of a molecule includes the classical molecular mechanical energy (which is understood as the free energy in vacuum) and the solvation energy, which is caused by the change of the environment of the molecule (solute) from vacuum ... Keywords: error analysis, fast summation, generalized Born, molecular surface

Chandrajit Bajaj; Wenqi Zhao

2009-11-01T23:59:59.000Z

47

Reactions of Solvated Ions Final Report  

DOE R&D Accomplishments (OSTI)

Brief summaries are presented on isotopic dilution studies on salts dissolved in CH{sub 3}OH, studies on metal and metal salts in solvents of the amine type, and studies on phosphato complexes of the pentammine Co(III) series. A list of papers published on reactions of solvated ions is included. (N.W.R.)

Taube, H.

1962-09-24T23:59:59.000Z

48

Time-frequency resolved ultrafast spectroscopy techniques using wavelet analysis  

E-Print Network (OSTI)

New experimental techniques based on non-linear ultrafast spectroscopies have been developed over the last few years, and have been demonstrated to provide powerful probes of quantum dynamics in different types of molecular aggregates, including both natural and artificial light harvesting complexes. Fourier transform-based spectroscopies have been particularly successful, yet 'complete' spectral information normally necessitates the loss of all information on the temporal sequence of events in a signal. This information though is particularly important in transient or multi-stage processes, in which the spectral decomposition of the data evolves in time. By going through several examples of ultrafast quantum dynamics, we demonstrate that the use of wavelets provide an efficient and accurate way to simultaneously acquire both temporal and frequency information about a signal, and argue that this greatly aids the elucidation and interpretation of physical process responsible for non-stationary spectroscopic features, such as those encountered in coherent excitonic energy transport.

Javier Prior; Enrique Castro; Alex W. Chin; Javier Almeida; Susana F. Huelga; Martin B. Plenio

2013-08-21T23:59:59.000Z

49

Watching a Protein as it Functions | Advanced Photon Source  

NLE Websites -- All DOE Office Websites (Extended Search)

of Light Elements in the Earth's Core A New Material for Warm-White LEDs Probing Ultrafast Solvation Dynamics with High Repetition-Rate LaserX-ray Methodologies Ultrafast...

50

The ALS X-Ray Streak Camera: Bringing the Ultrafast and Ultrasmall into  

NLE Websites -- All DOE Office Websites (Extended Search)

The ALS X-Ray Streak Camera: Bringing the Ultrafast and Ultrasmall into Focus Print The ALS X-Ray Streak Camera: Bringing the Ultrafast and Ultrasmall into Focus Print Studying the world of the ultrasmall and the ultrafast is at the frontier of scientific research. Two x-ray approaches can be used for ultrafast examinations. The first entails developing sources that have short x-ray pulses such as free-electron lasers and slicing sources, which will provide the ultrafast temporal information. The other approach is to develop a detector that is fast enough to resolve the ultrafast details of the dynamical processes. ALS researchers are taking the second path but adding a spatial resolution capability; that is, they are developing a high-speed x-ray streak camera with high spatial resolution to watch, in real time, the motion of the atoms in materials. So far, a temporal resolution of 233 fs and a spatial resolution of 10 mm have been demonstrated. This is the first time that such a high temporal resolution has been combined with high spatial resolution in a streak camera.

51

The ALS X-Ray Streak Camera: Bringing the Ultrafast and Ultrasmall into  

NLE Websites -- All DOE Office Websites (Extended Search)

The ALS X-Ray Streak Camera: Bringing the Ultrafast and Ultrasmall into Focus Print The ALS X-Ray Streak Camera: Bringing the Ultrafast and Ultrasmall into Focus Print Studying the world of the ultrasmall and the ultrafast is at the frontier of scientific research. Two x-ray approaches can be used for ultrafast examinations. The first entails developing sources that have short x-ray pulses such as free-electron lasers and slicing sources, which will provide the ultrafast temporal information. The other approach is to develop a detector that is fast enough to resolve the ultrafast details of the dynamical processes. ALS researchers are taking the second path but adding a spatial resolution capability; that is, they are developing a high-speed x-ray streak camera with high spatial resolution to watch, in real time, the motion of the atoms in materials. So far, a temporal resolution of 233 fs and a spatial resolution of 10 mm have been demonstrated. This is the first time that such a high temporal resolution has been combined with high spatial resolution in a streak camera.

52

The ALS X-Ray Streak Camera: Bringing the Ultrafast and Ultrasmall into  

NLE Websites -- All DOE Office Websites (Extended Search)

The ALS X-Ray Streak Camera: Bringing the Ultrafast and Ultrasmall into Focus Print The ALS X-Ray Streak Camera: Bringing the Ultrafast and Ultrasmall into Focus Print Studying the world of the ultrasmall and the ultrafast is at the frontier of scientific research. Two x-ray approaches can be used for ultrafast examinations. The first entails developing sources that have short x-ray pulses such as free-electron lasers and slicing sources, which will provide the ultrafast temporal information. The other approach is to develop a detector that is fast enough to resolve the ultrafast details of the dynamical processes. ALS researchers are taking the second path but adding a spatial resolution capability; that is, they are developing a high-speed x-ray streak camera with high spatial resolution to watch, in real time, the motion of the atoms in materials. So far, a temporal resolution of 233 fs and a spatial resolution of 10 mm have been demonstrated. This is the first time that such a high temporal resolution has been combined with high spatial resolution in a streak camera.

53

Anomalous Adsorption of Ultrafast Laser Irradiation in Glass ...  

Science Conference Proceedings (OSTI)

Presentation Title, Anomalous Adsorption of Ultrafast Laser Irradiation in Glass ... and is driven by the stress induced by absorption of ultrafast light in glass.

54

Laser wavelength effects in ultrafast near-field laser nanostructuring...  

NLE Websites -- All DOE Office Websites (Extended Search)

Laser wavelength effects in ultrafast near-field laser nanostructuring of Si Title Laser wavelength effects in ultrafast near-field laser nanostructuring of Si Publication Type...

55

Microsoft Word - Ultrafast symposium agenda7.doc  

NLE Websites -- All DOE Office Websites (Extended Search)

Wishart, BNL 8:55 Design and construction of ultrafast pulse radiolysis system using laser photocathode rf-gun combined with fs laser, University of Tokyo, Yusa Muroya,...

56

Solvation and Ionic Transport in Polymer Electrolyte Membranes  

DOE Green Energy (OSTI)

We developed a general theoretical framework to study the problem of proton solvation and transport in Nafion{reg_sign} and related materials.

Zawodzinski, T.A., Jr.; Paddison, S.J.; Reagor, D.; Pratt, L.R.

1999-06-03T23:59:59.000Z

57

Lithium Diisopropylamide Solvated by Hexamethylphosphoramide: Substrate-Dependent  

E-Print Network (OSTI)

Lithium Diisopropylamide Solvated by Hexamethylphosphoramide: Substrate-Dependent Mechanisms-1301 Received February 9, 2006; E-mail: dbc6@cornell.edu Abstract: Lithium diisopropylamide of lithium-ion solvation at a molecular level of resolution.5 Our interest in HMPA stems from studies

Collum, David B.

58

Lithium Hexamethyldisilazide: A View of Lithium Ion Solvation  

E-Print Network (OSTI)

Lithium Hexamethyldisilazide: A View of Lithium Ion Solvation through a Glass-Bottom Boat BRETT L and reactivities, we were drawn to lithium hexamethyldisilazide (LiHMDS; (Me3Si)2NLi) by its promi- nence principles of lithium ion coordination chemistry.2 Understanding how solvation influences organolithium

Collum, David B.

59

NANO EXPRESS Open Access Ultrafast nano-oscillators based on interlayer-  

E-Print Network (OSTI)

NANO EXPRESS Open Access Ultrafast nano-oscillators based on interlayer- bridged carbon nanoscrolls nano-oscillators based on carbon nanoscrolls (CNSs) using molecular dynamics simulations. Initiated of gigahertz. We demonstrate an effective strategy to reduce the dissipation of the CNS-based nano

Li, Teng

60

Ultrafast Enhancement of Ferromagnetism via Photoexcited Holes inGaMnAs  

SciTech Connect

We report on the observation of ultrafast photo-enhanced ferromagnetism in GaMnAs. It is manifested as a transient magnetization increase on a 100-ps time scale, after an initial sub-ps demagnetization. The dynamic magnetization enhancement exhibits a maximum below the Curie temperature {Tc} and dominates the demagnetization component when approaching {Tc}. We attribute the observed ultrafast collective ordering to the p-d exchange interaction between photoexcited holes and Mn spins, leading to a correlation-induced peak around 20K and a transient increase in {Tc}.

Wang, J.; Cotoros, I.; Dani, K.M.; Liu, X.; Furdyna, J.K.; Chemla, D.S.

2007-02-17T23:59:59.000Z

Note: This page contains sample records for the topic "ultrafast solvation dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Experimental demonstration of high quality MeV ultrafast electron diffraction  

SciTech Connect

The simulation optimization and an experimental demonstration of improved performances of mega-electron-volt ultrafast electron diffraction (MeV UED) are reported in this paper. Using ultrashort high quality electron pulses from an S-band photocathode rf gun and a polycrystalline aluminum foil as the sample, we experimentally demonstrated an improved spatial resolution of MeV UED, in which the Debye-Scherrer rings of the (111) and (200) planes were clearly resolved. This result showed that MeV UED is capable to achieve an atomic level spatial resolution and a -100 fs temporal resolution simultaneously, and will be a unique tool for ultrafast structural dynamics studies.

Li, R.; Tang, C., Du, Y., Huang, W., Du, Q., Shi, J., Yan, L., Wang, X.

2009-08-18T23:59:59.000Z

62

A coupled RISM/MD or MC simulation methodology for solvation free energies  

E-Print Network (OSTI)

A coupled RISM/MD or MC simulation methodology for solvation free energies Holly Freedman, Thanh N methods for determination of solvation free energies. We employ the RISM formulation of solvation free-netted chain equations. We apply this approach to determining free energies of solvation for several small

Truong, Thanh N.

63

Ultrafast dynamics of electrons at interfaces  

Science Conference Proceedings (OSTI)

Electronic states of a thin layer of material on a surface possess unique physical and chemical properties. Some of these properties arise from the reduced dimensionality of the thin layer with respect to the bulk or the properties of the electric field where two materials of differing dielectric constants meet at an interface. Other properties are related to the nature of the surface chemical bond. Here, the properties of excess electrons in thin layers of Xenon, Krypton, and alkali metals are investigated, and the bound state energies and effective masses of the excess electrons are determined using two-photon photoemission. For Xenon, the dependence of bound state energy, effective mass, and lifetime on layer thickness from one to nine layers is examined. Not all quantities were measured at each coverage. The two photon photoemission spectra of thin layers of Xenon on a Ag(111) substrate exhibit a number of sharp, well-defined peaks. The binding energy of the excess electronic states of Xenon layers exhibited a pronounced dependence on coverage. A discrete energy shift was observed for each additional atomic layer. At low coverage, a series of states resembling a Rydberg series is observed. This series is similar to the image state series observed on clean metal surfaces. Deviations from image state energies can be described in terms of the dielectric constant of the overlayer material and its effect on the image potential. For thicker layers of Xe (beyond the first few atomic layers), the coverage dependence of the features begins to resemble that of quantum well states. Quantum well states are related to bulk band states. However, the finite thickness of the layer restricts the perpendicular wavevector to a discrete set of values. Therefore, the spectrum of quantum well states contains a series of peaks which correspond to the various allowed values of the perpendicular wavevector. Analysis of the quantum well spectrum yields electronic band structure information. In this case, the quantum well states examined are derived from the Xenon conduction band. Measurements of the energies as a function of coverage yield the dispersion along the axis perpendicular to the surface while angle-resolved two-photon photoemission measurements yield information about dispersion along the surface parallel. The relative importance of the image potential and the overlayer band structure also depends on the quantum number and energy of the state. Some members of the image series may have an energy which is in an energy gap of the layer material, therefore such states may tend to remain physically outside the layer and retain much of their image character even at higher coverages. This is the case for the n = 1 image state of the Xe/Ag(111) system. The energies of image states which are excluded from the layer have a complex dependence on the thickness of the layer and its dielectric constant. The population decay kinetics of excited electronic states of the layer were also determined. Lifetimes are reported for the first three excited states for 1-6 atomic layers of Xe on Ag(111). As the image states evolve into quantum well states with increasing coverage, the lifetimes undergo an oscillation which marks a change in the spatial extent of the state. For example, the n = 2 quantum well state decreases substantially at 3-5 layers as the electron probability density in the layer increases. The lifetime data are modeled by extending the two-band nearly-free-electron approximation to account for the insulating Xe layer.

McNeill, Jason D.

1999-05-03T23:59:59.000Z

64

4th-International Symposium on Ultrafast Surface Science - Final Report  

SciTech Connect

The 4-th International Symposium on Ultrafast Surface Dynamics (UDS4) was held at the Telluride Summer Research Center on June 22-27, 2003. The International Organizing Committee consisting of Hrvoje Petek (USA), Xiaoyang Zhu (USA), Pedro Echenique (Spain) and Maki Kawai (Japan) brought together a total of 51 participants 16 of whom were from Europe, 10 from Japan, and 25 from the USA. The focus of the conference was on ultrafast electron or light induced processes at well-defined surfaces. Ultrafast surface dynamics concerns the transfer of charge and energy at solid surfaces on the femtosecond time scale. These processes govern rates of fundamental steps in surface reactions, interfacial electron transfer in molecular electronics, and relaxation in spin transport. Recent developments in femtosecond laser technology make it possible to measure by a variety of nonlinear optical techniques directly in the time domain the microscopic rates underlying these interfacial processes. Parallel progress in scanning probe microscopy makes it possible at a single molecular level to perform the vibrational and electronic spectroscopy measurements, to induce reactions with tunneling electrons, and to observe their outcome. There is no doubt that successful development in the field of ultrafast surface dynamics will contribute to many important disciplines.

Hrvoje Petek

2005-01-26T23:59:59.000Z

65

Solvation and Solvatochromism in CO2-Expanded Liquids. 3. The Dynamics of Nonspecific Preferential Solvation  

E-Print Network (OSTI)

applications in the area of design (Kubic and Stein, 1988; Tarifa and Chiotti, 1995). Majozi and Zhu (2001

Maroncelli, Mark

66

Multibounce light transport analysis using ultrafast imaging for material acquisition  

E-Print Network (OSTI)

This thesis introduces a novel framework for analysis of multibounce light transport using time-of-flight imaging for the applications of ultrafast reflectance acquisition and imaging through scattering media. Using ultrafast ...

Naik, Nikhil, S.M. Massachusetts Institute of Technology

2012-01-01T23:59:59.000Z

67

SLIDER - Rapid Optical Deflector for Recording Ultrafast Signals  

home \\ technologies \\ slider. Technologies: Ready-to-Sign Licenses: Software: Patents: SLIDER - Rapid Optical Deflector for Recording Ultrafast Signals. Contact.

68

Atomic Resolution Coherent Diffractive Imaging and Ultrafast Science  

Science Conference Proceedings (OSTI)

A major scientific challenge is determining the 3-D atomic structure of small nanostructures, including single molecules. Coherent diffractive imaging (CDI) is a promising approach. Recent progress has demonstrated coherent diffraction patterns can be recorded from individual nanostructures and phased to reconstruct their structure. However, overcoming the dose limit imposed by radiation damage is a major obstacle toward the full potential of CDI. One approach is to use ultrafast x-ray or electron pulses. In electron diffraction, amplitudes recorded in a diffraction pattern are unperturbed by lens aberrations, defocus, and other microscope resolution-limiting factors. Sub-A signals are available beyond the information limit of direct imaging. Significant contrast improvement is obtained compared to high-resolution electron micrographs. progress has also been made in developing time-resolved electron diffraction and imaging for the study of ultrafast dynamic processes in materials. This talk will cover these crosscutting issues and the convergence of electron and x-ray diffraction techniques toward structure determination of single molecules.

Zuo, Jian-min [University of Illinois

2011-01-12T23:59:59.000Z

69

Ultrafast Spectroscopy of Warm Dense Matter  

NLE Websites -- All DOE Office Websites (Extended Search)

Ultrafast Spectroscopy of Warm Dense Matter Print Ultrafast Spectroscopy of Warm Dense Matter Print Being neither solid, liquid, gas, nor plasma, warm dense matter (WDM) occupies a no man's land in the map of material phases. Its temperature can range between that of planetary cores (tens of thousands K) to that of stellar cores (hundreds of thousands K). Not only is it prevalent throughout the universe, it is relevant to inertial confinement fusion (ICF) and material performance under extreme conditions. However, because of its extreme temperatures and pressures, WDM tends to be drastically transient and thus difficult to study in the laboratory. Now, researchers have set up ultrafast x-ray absorption spectroscopy at the ALS to measure the electronic structure of WDMs, demonstrating that fast-changing electron temperatures of matter under extreme conditions can be determined with picosecond resolution.

70

SISGR: Linking Ion Solvation and Lithium Battery Electrolyte Properties  

DOE Green Energy (OSTI)

The solvation and phase behavior of the model battery electrolyte salt lithium trifluoromethanesulfonate (LiCF3SO3) in commonly used organic solvents; ethylene carbonate (EC), gamma-butyrolactone (GBL), and propylene carbonate (PC) was explored. Data from differential scanning calorimetry (DSC), Raman spectroscopy, and X-ray diffraction were correlated to provide insight into the solvation states present within a sample mixture. Data from DSC analyses allowed the construction of phase diagrams for each solvent system. Raman spectroscopy enabled the determination of specific solvation states present within a solvent-Ã?Â?Ã?Â?salt mixture, and X-ray diffraction data provided exact information concerning the structure of a solvates that could be isolated Thermal analysis of the various solvent-salt mixtures revealed the phase behavior of the model electrolytes was strongly dependent on solvent symmetry. The point groups of the solvents were (in order from high to low symmetry): C2V for EC, CS for GBL, and C1 for PC(R). The low symmetry solvents exhibited a crystallinity gap that increased as solvent symmetry decreased; no gap was observed for EC-LiTf, while a crystallinity gap was observed spanning 0.15 to 0.3 mole fraction for GBL-LiTf, and 0.1 to 0.33 mole fraction for PC(R)-LiTf mixtures. Raman analysis demonstrated the dominance of aggregated species in almost all solvent compositions. The AGG and CIP solvates represent the majority of the species in solutions for the more concentrated mixtures, and only in very dilute compositions does the SSIP solvate exist in significant amounts. Thus, the poor charge transport characteristics of CIP and AGG account for the low conductivity and transport properties of LiTf and explain why is a poor choice as a source of Li+ ions in a Li-ion battery.

Trulove, Paul C; Foley, Matthew P

2013-03-14T23:59:59.000Z

71

Studies of cosolvent systems in supercritical ethane using solvated electrons.  

DOE Green Energy (OSTI)

In this paper, pulse-radiolytic studies of the methanol-ethane cosolvent system are carried out. Our results show that at temperatures below approximately 110 C, there are high local concentrations of alcohols (clusters) that are capable of solvating an electron, suggesting a size of approximately 4-5 methanol molecules at approximately 0.15 mole fraction alcohol. Reactions have been carried out between these solvated electrons and silver ions that are (presumably) dissolved in other small clusters of alcohols. These results show that the reaction between species in two different clusters is approximately 2 orders of magnitude slower than diffusion-controlled reactions.

Dimitrijevic, N. M.; Bartels, D. M.; Jonah, C. D.; Takahashi, K.

2000-11-14T23:59:59.000Z

72

Microscopic linear liquid streams in vacuum: Injection of solvated biological samples into X-ray free electron lasers  

SciTech Connect

Microscopic linear liquid free-streams offer a means of gently delivering biological samples into a probe beam in vacuum while maintaining the sample species in a fully solvated state. By employing gas dynamic forces to form the microscopic liquid stream (as opposed to a conventional solid-walled convergent nozzle), liquid free-streams down to 300 nm diameter have been generated. Such 'Gas Dynamic Virtual Nozzles' (GDVN) are ideally suited to injecting complex biological species into an X-ray Free Electron Laser (XFEL) to determine the structure of the biological species via Serial Femtosecond Crystallography (SFX). GDVN injector technology developed for this purpose is described.

Doak, R. B.; DePonte, D. P.; Nelson, G.; Camacho-Alanis, F.; Ros, A.; Spence, J. C. H.; Weierstall, U. [Arizona State University, Tempe, AZ 85287-1504 (United States); Centre for Free-Electron Laser Science, DESY, D-22607 Hamburg (Germany); Arizona State University, Tempe, AZ 85287-1504 (United States)

2012-11-27T23:59:59.000Z

73

Two New Types of Ultrafast Aircraft Thermometer  

Science Conference Proceedings (OSTI)

A new version of an ultrafast aircraft resistance thermometer (UFT-F) with a time constant of the order 10?4 s,for use in both cloudy and cloudless air, is described. It evolved from an earlier version (UFT-S). Its sensing element is similar to ...

Krzysztof E. Haman; Szymon P. Malinowski; Bo?ena D. Stru?; Reinhold Busen; Andrzej Stefko

2001-02-01T23:59:59.000Z

74

Ultrafast three-dimensional x-ray computed tomography  

SciTech Connect

X-ray computed tomography (CT) is a well established visualization technique in medicine and nondestructive testing. However, since CT scanning requires sampling of radiographic projections from different viewing angles, common CT systems with mechanically moving parts are too slow for dynamic imaging, for instance of multiphase flows or live animals. Here, we introduce an ultrafast three-dimensional x-ray CT method based on electron beam scanning, which achieves volume rates of 500 s{sup -1}. Primary experiments revealed the capability of this method to recover the structure of phase boundaries in gas-solid and gas-liquid two-phase flows, which undergo three-dimensional structural changes in the millisecond scale.

Bieberle, Martina; Barthel, Frank; Hampel, Uwe [Institute of Safety Research, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden (Germany); Menz, Hans-Juergen; Mayer, Hans-Georg [Institute of Nuclear Technology and Energy Systems, University of Stuttgart, 70569 Stuttgart (Germany)

2011-01-17T23:59:59.000Z

75

The Effects of Interfaces on the Ultrafast Irradiation of Thin Films  

Science Conference Proceedings (OSTI)

Presentation Title, The Effects of Interfaces on the Ultrafast Irradiation of Thin Films ... Abstract Scope, The ultrafast laser irradiation of bulk materials is a ...

76

Ultrafast thin-film laser-induced breakdown spectroscopy of doped...  

NLE Websites -- All DOE Office Websites (Extended Search)

Ultrafast thin-film laser-induced breakdown spectroscopy of doped oxides Title Ultrafast thin-film laser-induced breakdown spectroscopy of doped oxides Publication Type Journal...

77

Femtosecond Lattice Dynamics in Photoexcited Bismuth  

NLE Websites -- All DOE Office Websites (Extended Search)

Lattice Dynamics in Photoexcited Bismuth One of the grand challenges of ultrafast science is to follow directly atomic motion of a photo-induced reaction on the fastest time-scales...

78

Effects of Ultrafast Laser Micromachining on Structure and ...  

Science Conference Proceedings (OSTI)

Presentation Title, Effects of Ultrafast Laser Micromachining on Structure and Mechanical Properties of 316 LVM Stainless Steel. Author(s), Hossein Lavvafi, ...

79

Ultra-Fast Calorimetry for Studies of Crystallization in ...  

Science Conference Proceedings (OSTI)

Presentation Title, Ultra-Fast Calorimetry for Studies of Crystallization in Chalcogenides for Phase-Change Memory. Author(s), A. L. Greer. On-Site Speaker ...

80

INTERNATIONAL SYMPOSIUM ON ULTRAFAST ACCELERATORS FOR PULSE RADIOLYSIS  

NLE Websites -- All DOE Office Websites (Extended Search)

and poster set-up 8:20 Introductory remarks (J. F. Wishart, J. R. Miller) Session I: Ultrafast radiolysis facilities: Photocathode systems (Including accelerator system designs...

Note: This page contains sample records for the topic "ultrafast solvation dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Probing surface chemistry using 'Operando' and 'Ultrafast' soft...  

NLE Websites -- All DOE Office Websites (Extended Search)

Probing surface chemistry using 'Operando' and 'Ultrafast' soft x-ray spectroscopies Wednesday, December 18, 2013 - 3:00pm SLAC, Redtail Hawk Conference Room 108A Hirohito...

82

Argonne CNM Highlight: Award for Ultrafast Imaging of Solar Energy...  

NLE Websites -- All DOE Office Websites (Extended Search)

CNM's Nanophotonics Group and Argonne Chemical Sciences and Engineering's (CSE's) Photosynthesis Group, presented her poster, "Ultrafast Imaging of Solar Energy Flow in...

83

Ultra-fast framing camera tube  

DOE Patents (OSTI)

An electronic framing camera tube features focal plane image dissection and synchronized restoration of the dissected electron line images to form two-dimensional framed images. Ultra-fast framing is performed by first streaking a two-dimensional electron image across a narrow slit, thereby dissecting the two-dimensional electron image into sequential electron line images. The dissected electron line images are then restored into a framed image by a restorer deflector operated synchronously with the dissector deflector. The number of framed images on the tube's viewing screen is equal to the number of dissecting slits in the tube. The distinguishing features of this ultra-fast framing camera tube are the focal plane dissecting slits, and the synchronously-operated restorer deflector which restores the dissected electron line images into a two-dimensional framed image. The framing camera tube can produce image frames having high spatial resolution of optical events in the sub-100 picosecond range.

Kalibjian, Ralph (1051 Batavia Ave., Livermore, CA 94550)

1981-01-01T23:59:59.000Z

84

Relativistic ultrafast rendering using time-of-flight imaging  

Science Conference Proceedings (OSTI)

We capture ultrafast movies of light in motion and synthesize physically valid visualizations. The effective exposure time for each frame is under two picoseconds (ps). Capturing a 2D video with this time resolution is highly challenging, given the low ... Keywords: relativistic effects, streak sensor, time-resolved imaging, ultrafast optics

Andreas Velten; Di Wu; Adrian Jarabo; Belen Masia; Christopher Barsi; Everett Lawson; Chinmaya Joshi; Diego Gutierrez; Moungi G. Bawendi; Ramesh Raskar

2012-08-01T23:59:59.000Z

85

A recirculating linac-based facility for ultrafast X-ray science  

SciTech Connect

We present an updated design for a proposed source of ultra-fast synchrotron radiation pulses based on a recirculating superconducting linac, in particular the incorporation of EUV and soft x-ray production. The project has been named LUX - Linac-based Ultrafast X-ray facility. The source produces intense x-ray pulses with duration of 10-100 fs at a 10 kHz repetition rate, with synchronization of 10 s fs, optimized for the study of ultra-fast dynamics. The photon range covers the EUV to hard x-ray spectrum by use of seeded harmonic generation in undulators, and a specialized technique for ultra-short-pulse photon production in the 1-10 keV range. High-brightness rf photocathodes produce electron bunches which are optimized either for coherent emission in free-electron lasers, or to provide a large x/y emittance ration and small vertical emittance which allows for manipulation to produce short-pulse hard x-rays. An injector linac accelerates the beam to 120 MeV, and is followed by four passes through a 600-720 MeV recirculating linac. We outline the major technical components of the proposed facility.

Corlett, J.N; Barletta, W.A.; DeSantis, S.; Doolittle, L.; Fawley, W.M.; Green, M.A.; Heimann, P.; Leone, S.; Lidia, S.; Li, D.; Ratti, A.; Robinson, K.; Schoenlein, R.; Staples, J.; Wan, W.; Wells, R.; Wolski, A.; Zholents, A.; Placidi, M.; Pirkl, W.; Parmigiani, F.

2003-05-06T23:59:59.000Z

86

Temperature-Dependent Dynamics and Friction in IL Local Environments  

NLE Websites -- All DOE Office Websites (Extended Search)

Wishart, and E. W. Castner, Jr. J. Phys. Chem. B 111, 4963-4977 (2007). Find paper at ACS Publications or use ACS Articles on Request Abstract: The solvation dynamics and local...

87

Aqueous Solvation Free Energies of Ions and Ion?Water Clusters Based on an Accurate Value for the Absolute Aqueous Solvation Free Energy of the Proton  

E-Print Network (OSTI)

TITLE RUNNING HEAD: Aqueous solvation free energies of ions and ion?water clusters Abstract: Thermochemical cycles that involve pKa, gas-phase acidities, aqueous solvation free energies of neutral species, and gas-phase clustering free energies have been used with the cluster pair approximation to determine the absolute aqueous solvation free energy of the proton. The best value obtained in this work is in good agreement with the value reported by Tissandier et al. (Tissandier, M. D.; Cowen, K. A.;

Christopher J. Cramer; Donald G. Truhlar

2006-01-01T23:59:59.000Z

88

Bond-valence methods for pKa prediction. II. Bond-valence, electrostatic, molecular geometry, and solvation effects  

DOE Green Energy (OSTI)

In a previous contribution, we outlined a method for predicting (hydr)oxy-acid and oxide surface acidity constants based on three main factors: bond valence, Me?O bond ionicity, and molecular shape. Here electrostatics calculations and ab initio molecular dynamics simulations are used to qualitatively show that Me?O bond ionicity controls the extent to which the electrostatic work of proton removal departs from ideality, bond valence controls the extent of solvation of individual functional groups, and bond valence and molecular shape controls local dielectric response. These results are consistent with our model of acidity, but completely at odds with other methods of predicting acidity constants for use in multisite complexation models. In particular, our ab initio molecular dynamics simulations of solvated monomers clearly indicate that hydrogen bonding between (hydr)oxo-groups and water molecules adjusts to obey the valence sum rule, rather than maintaining a fixed valence based on the coordination of the oxygen atom as predicted by the standard MUSIC model.

Bickmore, Barry R.; Rosso, Kevin M.; Tadanier, Christopher J.; Bylaska, Eric J.; Doud, Darrin

2006-08-15T23:59:59.000Z

89

Dielectric Boundary Force in Molecular Solvation with the PoissonBoltzmann Free Energy: A Shape  

E-Print Network (OSTI)

Dielectric Boundary Force in Molecular Solvation with the Poisson­Boltzmann Free Energy: A Shape boundary force acting on such a boundary is the negative first variation of the elec- trostatic free energy [17,18,35,43,44]. Such a predefined interface is used to compute the solvation free energy as the sum

Li, Bo

90

Computing Relative Free Energies of Solvation Using Single Reference Thermodynamic Integration Augmented  

E-Print Network (OSTI)

Computing Relative Free Energies of Solvation Using Single Reference Thermodynamic Integration relative transformation free energies in a series of molecules with respect to a single reference state of the SR-TI variant is demonstrated in calculations of relative solvation free energies for a series

91

Time scales and pathways for kinetic energy relaxation in solvated proteins: Application to carbonmonoxy myoglobin  

E-Print Network (OSTI)

of ki- netic energy equipartitioning compared to that of the hydro- gen atoms. These backbone atomsTime scales and pathways for kinetic energy relaxation in solvated proteins: Application, the rates of kinetic energy partitioning for various elements of solvated carboxy-myoglobin were calculated

Straub, John E.

92

Apparatus and method for characterizing ultrafast polarization varying optical pulses  

DOE Patents (OSTI)

Practical techniques are described for characterizing ultrafast potentially ultraweak, ultrashort optical pulses. The techniques are particularly suited to the measurement of signals from nonlinear optical materials characterization experiments, whose signals are generally too weak for full characterization using conventional techniques.

Smirl, Arthur (1020 Cherry La. Northwest, Iowa City, IA 52240); Trebino, Rick P. (425 Mulqueeny St., Livermore, CA 94550)

1999-08-10T23:59:59.000Z

93

Nucleation and Growth Observed by Ultrafast SAXS and WAXS  

Science Conference Proceedings (OSTI)

To access these early stages of particle formation we have undertaken ultrafast SAXS and WAXS measurements in the free jet at the exit of a micro-T-mixer ...

94

Ultrafast Imaging of Electron Waves in Graphene | Advanced Photon...  

NLE Websites -- All DOE Office Websites (Extended Search)

| Subscribe to APS Science Highlights rss feed Ultrafast Imaging of Electron Waves in Graphene NOVEMBER 9, 2010 Bookmark and Share A frame from one of the electron-motion movies...

95

High-performance laser processing using manipulated ultrafast laser pulses  

Science Conference Proceedings (OSTI)

We employ manipulated ultrafast laser pulses to realize microprocessing with high-performance. Efficient microwelding of glass substrates by irradiation by a double-pulse train of ultrafast laser pulses is demonstrated. The bonding strength of two photostructurable glass substrates welded by double-pulse irradiation was evaluated to be 22.9 MPa, which is approximately 22% greater than that of a sample prepared by conventional irradiation by a single pulse train. Additionally, the fabrication of hollow microfluidic channels with a circular cross-sectional shape embedded in fused silica is realized by spatiotemporally focusing the ultrafast laser beam. We show both theoretically and experimentally that the spatiotemporal focusing of ultrafast laser beam allows for the creation of a three-dimensionally symmetric spherical peak intensity distribution at the focal spot.

Sugioka, Koji; Cheng Ya; Xu Zhizhan; Hanada, Yasutaka; Midorikawa, Katsumi [RIKEN - Advanced Science Institute, Wako, Saitama 351-0198 (Japan); State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences (China); RIKEN - Advanced Science Institute, Wako, Saitama 351-0198 (Japan)

2012-07-30T23:59:59.000Z

96

The ALS X-Ray Streak Camera: Bringing the Ultrafast and Ultrasmall...  

NLE Websites -- All DOE Office Websites (Extended Search)

The ALS X-Ray Streak Camera: Bringing the Ultrafast and Ultrasmall into Focus The ALS X-Ray Streak Camera: Bringing the Ultrafast and Ultrasmall into Focus Print Wednesday, 26...

97

An ultrafast x-ray detector system at an elliptically polarizing undulator beamline  

E-Print Network (OSTI)

has been developed at the ALS for the study of ultrafastAdvanced Light Source (ALS). A streak camera is a detector2 Experimental setup The ALS ultrafast x-ray detector system

2008-01-01T23:59:59.000Z

98

Ultrafast optical pulse manipulation in three dimensional-resolved microscope imaging and microfabrication  

E-Print Network (OSTI)

The availability of lasers with femtosecond, ultrafast light pulses provides new opportunities and challenges in instrument design. This thesis addresses three aspects of utilizing ultrafast light pulses in two-photon ...

Kim, Daekeun, Ph. D. Massachusetts Institute of Technology

2009-01-01T23:59:59.000Z

99

Fast Calculations of Electrostatic Solvation Free Energy from Reconstructed Solvent Density Using Proximal Radial Distribution Functions  

SciTech Connect

Although detailed atomic models may be applied for a full description of solvation, simpler phenomenologicalmodels are particularly useful to interpret the results for scanning many large, complex systems, where a full atomic model is too computationally expensive to use. Among the most costly are solvation free-energy evaluations by simulation. Here we develop a fast way to calculate electrostatic solvation free energy while retaining much of the accuracy of explicit solvent free-energy simulation. The basis of our method is to treat the solvent not as a structureless dielectric continuum but as a structured medium by making use of universal proximal radial distribution functions. Using a deca-alanine peptide as a test case, we compare the use of our theory with free-energy simulations and traditional continuum estimates of the electrostatic solvation free energy.

Lin, Bin; Wong, Ka-Yiu; Hu, Char Y.; Kokubo, Hironori; Pettitt, Bernard M.

2011-07-07T23:59:59.000Z

100

PUBLICATIONS "Ultrafast Photoluminescence Dynamics Of Nitride Passivated Silicon  

E-Print Network (OSTI)

as psychological differences between individuals are not ad- dressed (Hulin, 1971). Efforts focused primarily.V. (1959). The motivation to work. New York: Wiley. Hulin, C.L. (1971). Individual differences and job-Bass. Renwick, P.A. (1975). Perception and management of superior­subordinate conflict. Organiza- tional

Fauchet, Philippe

Note: This page contains sample records for the topic "ultrafast solvation dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Ultrafast Electron Diffraction Studies of Lattice Dynamics in Thin ...  

Science Conference Proceedings (OSTI)

What Can we Learn from Atomic Scale Calculations of Grain Boundary Properties? What Can We Learn from Measurements of Li-ion Battery Single Particles?

102

Calculation of the Gibbs Free Energy of Solvation and Dissociation of HCl in Water via Monte Carlo Simulations and Continuum Solvation Models  

Science Conference Proceedings (OSTI)

The free energy of solvation and dissociation of hydrogen chloride in water is calculated through a combined molecular simulation quantum chemical approach at four temperatures between T = 300 and 450 K. The free energy is first decomposed into the sum of two components: the Gibbs free energy of transfer of molecular HCl from the vapor to the aqueous liquid phase and the standard-state free energy of acid dissociation of HCl in aqueous solution. The former quantity is calculated using Gibbs ensemble Monte Carlo simulations using either Kohn-Sham density functional theory or a molecular mechanics force field to determine the system’s potential energy. The latter free energy contribution is computed using a continuum solvation model utilizing either experimental reference data or micro-solvated clusters. The predicted combined solvation and dissociation free energies agree very well with available experimental data. CJM was supported by the US Department of Energy,Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy.

McGrath, Matthew; Kuo, I-F W.; Ngouana, Brice F.; Ghogomu, Julius N.; Mundy, Christopher J.; Marenich, Aleksandr; Cramer, Christopher J.; Truhlar, Donald G.; Siepmann, Joern I.

2013-08-28T23:59:59.000Z

103

Ultrafast laser induced breakdown spectroscopy of electrode/electrolyte  

NLE Websites -- All DOE Office Websites (Extended Search)

Ultrafast laser induced breakdown spectroscopy of electrode/electrolyte Ultrafast laser induced breakdown spectroscopy of electrode/electrolyte interfaces Title Ultrafast laser induced breakdown spectroscopy of electrode/electrolyte interfaces Publication Type Journal Article Year of Publication 2012 Authors Zormpa, Vasileia, Jaroslaw Syzdek, Xianglei Mao, Richard E. Russo, and Robert Kostecki Journal Applied Physics Letters Volume 100 Issue 23 Date Published 05-2012 ISSN 0003-6951 Keywords electrochemical electrodes, graphite, high-speed optical techniques, laser beam effects, organic compounds, pyrolysis, solid electrolytes Abstract Direct chemical analysis of electrode/electrolyte interfaces can provide critical information on surface phenomena that define and control the performance of Li-based battery systems. In this work, we introduce the use of ex situ femtosecond laser induced breakdown spectroscopy to probe compositional variations within the solid electrolyte interphase (SEI) layer. Nanometer-scale depth resolution was achieved for elemental and molecular depth profiling of SEI layers formed on highly oriented pyrolytic graphite electrodes in an organic carbonate-based electrolyte. This work demonstrates the unique ability of ultrafast laser spectroscopy as a highly versatile, light element-sensitive technique for direct chemical analysis of interfacial layers in electrochemical energy storage systems.

104

Apparatus and method for characterizing ultrafast polarization varying optical pulses  

DOE Patents (OSTI)

Practical techniques are described for characterizing ultrafast potentially ultraweak, ultrashort optical pulses. The techniques are particularly suited to the measurement of signals from nonlinear optical materials characterization experiments, whose signals are generally too weak for full characterization using conventional techniques. 2 figs.

Smirl, A.; Trebino, R.P.

1999-08-10T23:59:59.000Z

105

Ultrafast Control of Magnetism in Ferromagnetic Semiconductors via Photoexcited Transient Carriers  

SciTech Connect

The field of spintronics offers perspectives for seamless integration of coupled and inter-tunable electrical and magnetic properties in a single device. For integration of the spin degree of freedom with current electronic technology, new semiconductors are needed that show electrically-tunable magnetic properties at room temperature and above. Dilute magnetic semiconductors derived from III-V compounds, like GaMnAs and InMnAs, show coupled and tunable magnetic, transport, and optical properties, due to the fact that their ferromagnetism is hole-mediated. These unconventional materials are ideal systems for manipulating the magnetic order by changing the carrier polarization, population density, and energy band distribution of the complementary subsystem of holes. This is the main theme we cover in this thesis. In particular, we develop a unique setup by use of ultraviolet pump, near-infrared probe femtosecond laser pulses, that allows for magneto-optical Kerr effect (MOKE) spectroscopy experiments. We photo-excite transient carriers in our samples, and measure the induced transient magnetization dynamics. One set of experiments performed allowed us to observe for the first time enhancement of the ferromagnetic order in GaMnAs, on an ultrafast time scale of hundreds of picoseconds. The corresponding transient increase of Curie temperature (Tc, the temperature above which a ferromagnetic material loses its permanent magnetism) of about 1 K for our experimental conditions is a very promising result for potential spintronics applications, especially since it is seconded by observation of an ultrafast ferromagnetic to paramagnetic phase transition above Tc. In a different set of experiments, we"write" the magnetization in a particular orientation in the sample plane. Using an ultrafast scheme, we alter the distribution of holes in the system and detect signatures of the particular memory state in the subsequent magnetization dynamics, with unprecedented hundreds of femtosecond detection speed. The femtosecond cooperative magnetic phenomena presented here further our understanding of Mn-hole correlations in III-V dilute magnetic semiconductors, and may well represent universal principles of a large class of carrier-mediated ferromagnetic materials. Thus they offer perspectives for future terahertz (1012 Hz) speed"spintronic" functional devices.

Cotoros, Ingrid A.

2008-12-12T23:59:59.000Z

106

Ultrafast charge separation in organic photovoltaics enhanced by charge delocalization and vibronically hot exciton dissociation  

E-Print Network (OSTI)

In organic photovoltaics, the mechanism by which free electrons and holes are generated overcoming the Coulomb attraction is a currently much debated topic. To elucidate this mechanism at a molecular level, we carried out a combined electronic structure and quantum dynamical analysis that captures the elementary events from the exciton dissociation to the free carrier generation at polymer/fullerene donor-acceptor heterojunctions. Our calculations show that experimentally observed efficient charge separations can be explained by a combination of two effects: First, the delocalization of charges which substantially reduces the Coulomb barrier, and second, the vibronically hot nature of the charge transfer state which promotes charge dissociation beyond the barrier. These effects facilitate an ultrafast charge separation even at low-band-offset heterojunctions.

Tamura, Hiroyuki

2013-01-01T23:59:59.000Z

107

Solvation Free Energy of Biomacromolecules: Parameters for a Modified Generalized Born Model Consistent with the AMBER Force Field  

E-Print Network (OSTI)

Solvation Free Energy of Biomacromolecules: Parameters for a Modified Generalized Born Model provides rapid estimates of the electrostatic free energies of solvation for diverse molecules of parameters compatible with the AMBER force field is described. The method is used to estimate free energies

Jayaram, Bhyravabotla

108

Ultrafast X-ray and 2-dimensional UV Spectroscopy of TiO2 ...  

Science Conference Proceedings (OSTI)

Presentation Title, Ultrafast X-ray and 2-dimensional UV Spectroscopy of TiO2 Nanoparticles. Author(s), Majed Chergui. On-Site Speaker (Planned), Majed ...

109

Lithium Phenolates Solvated by Tetrahydrofuran and 1,2-Dimethoxyethane: Structure Determination Using the  

E-Print Network (OSTI)

Lithium Phenolates Solvated by Tetrahydrofuran and 1,2-Dimethoxyethane: Structure Determination: The method of continuous variation in conjunction with 6 Li NMR spectroscopy was used to characterize lithium substrate- and solvent-dependent combinations of lithium phenolate monomers, dimers, trimers, tetramers

Collum, David B.

110

Lithium Diisopropylamide Solvated by Monodentate and Bidentate Ligands: Solution Structures and Ligand Binding  

E-Print Network (OSTI)

Lithium Diisopropylamide Solvated by Monodentate and Bidentate Ligands: Solution Structures, 1997X Abstract: 6Li and 15N NMR spectroscopic studies of lithium diisopropylamide ([6Li]LDA and [6Li,15 are correlated with those obtained previously for lithium hexamethyldisilazide. Introduction Despite

Collum, David B.

111

Solvation Phenomena in Dilute Solutions: Formal, Experimental Evidence, and Modeling Implications  

Science Conference Proceedings (OSTI)

We review the fundamentals underlying a general molecular-based formalism for the microscopic interpretation of the solvation phenomena involving sparingly soluble solutes in compressible media, an approach that hinges around the unambiguous splitting of the species correlation function integrals into short-(finite) and long-ranged (diverging) contributions at infinite dilution, where this condition is taken as the reference system for the derivation of composition expansions. Then, we invoke the formalism (a) to illustrate the well-behaved nature of the solvation contributions to the mechanical partial molecular properties of solutes at infinite dilution, (b) to guide the development of, and provide molecular-based support to, the macroscopic modeling of high-temperature dilute aqueous-electrolyte solutions, (c) to study solvation effects on the kinetic rate constants of reactions in near-critical solvents in an attempt to understand from a microscopic perspective the macroscopic evidence regarding the thermodynamic pressure effects, and (d) to interpret the microscopic mechanism behind synergistic solvation effects involving either co-solutes or co-solvents, and provide a molecular argument on the unsuitability of the van der Waals one-fluid (vdW-1f) mixing rules for the 2 description of weakly attractive solutes in compressible solvents. Finally, we develop thermodynamically consistent perturbation expansions, around the infinite dilution reference, for the species residual properties in binary and ternary mixtures, and discuss the theoretical and modeling implications behind ad hoc first-order truncated expansions.

Chialvo, Ariel A [ORNL

2013-01-01T23:59:59.000Z

112

Dynamic  

Office of Legacy Management (LM)

Dynamic Dynamic , and Static , Res.ponse of the Government Oil Shale Mine at ' , . , Rifle, Colorado, to the Rulison Event. , . ; . . DISCLAIMER Portions of this document may be illegible in electronic image products. Images are produced from the best available original document. p ( y c - - a 2-1 0 -4- REPORT AT (29-2) 914 USBM 1 0 0 1 UNITED STATES DEPARTMENT O F THE I NTERIOR BUREAU OF MINES e s.09 P. L. R U S S E L L RESEARCH D l RECTOR Februory 2, lB7O DYNAMIC AND STATIC RESPONSE 'OF THE GOVERNMENT OIL SHALE MINE A T RIFLE, COLORADO, T O THE, RULISON EVENT ORDER FROM CFSTl A S ~ B ~ &J C / This page intentionally left blank CONTENTS Page . . . . . . . . . . . . . . . . . . . . . . . . . H i s t o r i c . a l Des c r i p t i o n 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Summary 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Introduction 3

113

Ultrafast terahertz probes of transient conducting and insulating phases in an electron-hole gas  

DOE Green Energy (OSTI)

Many-body systems in nature exhibit complexity and self-organization arising from seemingly simple laws. The long-range Coulomb interaction between electrical charges generates a plethora of bound states in matter, ranging from the hydrogen atom to complex biochemical structures. Semiconductors form an ideal laboratory for studying many-body interactions of quasi-particles among themselves and with lattice vibrations and light. Oppositely charged electron and hole quasi-particles can coexist in an ionized but correlated plasma, or form bound hydrogen-like pairs called excitons which strongly affect physical properties. The pathways between such states however remain elusive in near-visible optical experiments that detect a subset of excitons with vanishing center-of-mass momenta. In contrast, transitions between internal exciton levels which occur in the far-infrared at terahertz (10 s) frequencies are in dependent of this restriction suggesting their use as a novel pro be of pair dynamics. Here, we employ an ultrafast terahertz probe to directly investigate the dynamical interplay of optically-generated excitons and unbound electron-hole pairs in GaAs quantum wells. Our observations witness an unexpected quasi-instantaneous excitonic enhancement, reveal formation of insulating excitons on a hundred picosecond timescale and manifest conditions under which excitonic populations prevail.

Kaindl, Robert A.; Carnahan, Marc A.; Hagele, Daniel; Lovenich, Reinhold; Chemla, Daniel S.

2003-04-10T23:59:59.000Z

114

Ultrafast pulsed laser utilizing broad bandwidth laser glass  

DOE Patents (OSTI)

An ultrafast laser uses a Nd-doped phosphate laser glass characterized by a particularly broad emission bandwidth to generate the shortest possible output pulses. The laser glass is composed primarily of P{sub 2}O{sub 5}, Al{sub 2}O{sub 3} and MgO, and possesses physical and thermal properties that are compatible with standard melting and manufacturing methods. The broad bandwidth laser glass can be used in modelocked oscillators as well as in amplifier modules. 7 figs.

Payne, S.A.; Hayden, J.S.

1997-09-02T23:59:59.000Z

115

Ultrafast pulsed laser utilizing broad bandwidth laser glass  

DOE Patents (OSTI)

An ultrafast laser uses a Nd-doped phosphate laser glass characterized by a particularly broad emission bandwidth to generate the shortest possible output pulses. The laser glass is composed primarily of P.sub.2 O.sub.5, Al.sub.2 O.sub.3 and MgO, and possesses physical and thermal properties that are compatible with standard melting and manufacturing methods. The broad bandwidth laser glass can be used in modelocked oscillators as well as in amplifier modules.

Payne, Stephen A. (Castro Valley, CA); Hayden, Joseph S. (Clarks Summit, PA)

1997-01-01T23:59:59.000Z

116

Rise time measurement for ultrafast X-ray pulses  

Science Conference Proceedings (OSTI)

A pump-probe scheme measures the rise time of ultrafast x-ray pulses. Conventional high speed x-ray diagnostics (x-ray streak cameras, PIN diodes, diamond PCD devices) do not provide sufficient time resolution to resolve rise times of x-ray pulses on the order of 50 fs or less as they are being produced by modern fast x-ray sources. Here, we are describing a pump-probe technique that can be employed to measure events where detector resolution is insufficient to resolve the event. The scheme utilizes a diamond plate as an x-ray transducer and a p-polarized probe beam.

Celliers, Peter M. (Berkeley, CA); Weber, Franz A. (Oakland, CA); Moon, Stephen J. (Tracy, CA)

2005-04-05T23:59:59.000Z

117

Rise Time Measurement for Ultrafast X-Ray Pulses  

DOE Patents (OSTI)

A pump-probe scheme measures the rise time of ultrafast x-ray pulses. Conventional high speed x-ray diagnostics (x-ray streak cameras, PIN diodes, diamond PCD devices) do not provide sufficient time resolution to resolve rise times of x-ray pulses on the order of 50 fs or less as they are being produced by modern fast x-ray sources. Here, we are describing a pump-probe technique that can be employed to measure events where detector resolution is insufficient to resolve the event. The scheme utilizes a diamond plate as an x-ray transducer and a p-polarized probe beam.

Celliers, Peter M.; Weber, Franz A.; Moon, Stephen J.

2005-04-05T23:59:59.000Z

118

Dynamics  

NLE Websites -- All DOE Office Websites (Extended Search)

Hydration Hydration Water on Rutile Studied by Backscattering Neutron Spectroscopy and Molecular Dynamics Simulation E. Mamontov,* ,† D. J. Wesolowski, ‡ L. Vlcek, § P. T. Cummings, §,| J. Rosenqvist, ‡ W. Wang, ⊥ and D. R. Cole ‡ Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6473, Chemical Sciences DiVision, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6110, Department of Chemical Engineering, Vanderbilt UniVersity, NashVille, Tennessee 37235-1604, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6496, and EnVironmental Sciences DiVision, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6036 ReceiVed: December 20, 2007; ReVised Manuscript ReceiVed: June 4, 2008 The high energy resolution, coupled with the wide dynamic range, of the new backscattering

119

Kinetic solvation pressure: a measure of environmental effects on reaction rates. 1. Application to hydrophobic systems  

SciTech Connect

A quantity termed kinetic solvation pressure is defined as (/partial derivative//Delta/G/sup /double dagger////partial derivative//anti/V)/sub T/, where /anti/V is the reactant molar volume. It is identified with the difference in the amount of isothermal work, per unit volume expansion necessary to create a solvation cavity in a particular medium, upon transition-state complex formation. The quantity was evaluated for the hydrolysis of carboxylic esters mediated by different hydrophobic catalysts and was found to be equal to +26 J cm/sup /minus/3/ for the acid-catalyzed hydrolysis of n-alkyl acetates in water solvent; but it becomes negative when macro- or supramolecular acids were used as catalysts: /minus/16 J cm/sup /minus/3/ for Dowex 50W-X2, /minus/43J cm/sup /minus/3/ for poly(styrenesulfonic acid), /minus/64 J cm/sup /minus/3/ for dodecylsulfuric acid micelles. These results suggest the action of hydrophobic forces in enhancing the catalytic power of the supermolecules, relative to aqueous hydrogen ion. No such effect is seen in aqueous acetone or when more hydrophilic acetates are used as substrates. Kinetic solvation pressure for enzyme-catalyzed ester hydrolysis is five times more negative than for the resin system, indicating the full action of hydrophobic forces in the catalytic process.

Mata-Segreda, J.F.

1988-08-31T23:59:59.000Z

120

UPGRADING METHANE USING ULTRA-FAST THERMAL SWING ADSORPTION  

SciTech Connect

The purpose of this project is to design and demonstrate an approach to upgrade low-BTU methane streams from coal mines to pipeline-quality natural gas. The objective of Phase I of the project was to assess the feasibility of upgrading low-Btu methane streams using ultra-fast thermal swing adsorption (TSA) using Velocys' modular microchannel process technology. The project is on schedule and under budget. For Task 1.1, the open literature, patent information, and vendor contacts were surveyed to identify adsorbent candidates for experimental validation and subsequent demonstration in an MPT-based ultra-fast TSA separation for methane upgrading. The leading candidates for preferential adsorption of methane over nitrogen are highly microporous carbons. A Molecular Gate{trademark} zeolite from Engelhard Corporation has emerged as a candidate. For Task 1.2, experimental evaluation of adsorbents was initiated, and data were collected on carbon (MGN-101) from PICA, Inc. This carbon demonstrated a preferential capacity for methane over nitrogen, as well as a reasonable thermal swing differential capacity for a 90% methane and 10% nitrogen mixture. A similar methane swing capacity at 2 psig was measured. The mixture composition is relevant because gob gas contains nearly 85% methane and must be purified to 97% methane for pipeline quality.

Anna Lee Tonkovich

2004-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "ultrafast solvation dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Development of ZnO:Ga as an Ultrafast Scintillator  

DOE Green Energy (OSTI)

We report on several methods for synthesizing the ultra-fast scintillator ZnO(Ga), and measurements of the resulting products. This material has characteristics that make it an excellent alpha detector for tagging the time and direction of individual neutrons produced by t-d and d-d neutron generators (associated particle imaging). The intensity and decay time are strongly dependent on the method used for dopant incorporation. We compare samples made by diffusion of Ga metal to samples made by solid state reaction between ZnO and Ga2O3 followed by reduction in hydrogen. The latter is much more successful and has a pure, strong near-band-edge fluorescence and an ultra-fast decay time of the x-ray-excited luminescence. The luminescence increases dramatically as the temperature is reduced to 10K. We also present results of an alternate low-temperature synthesis that produces luminescent particles with a more uniform size distribution. We examine possible mechanisms for the bright near-band-edge scintillation and favor the explanation that it is due to the recombination of Ga3+ donor electrons with ionization holes trapped on H+ ion acceptors.

Bourret-Courchesne, E.D.; Derenzo, S.E.; Weber, M.J.

2008-12-10T23:59:59.000Z

122

Ab initio study of the structure and dynamics of solvated highly charged metal ions  

E-Print Network (OSTI)

autocorrelation function, RTD(t) computed for each value ofautocorrelation function, RTD(t), as described by Brunne et.of window size, t, for RTD(t) and HB(t) autocorrelation

Bogatko, Stuart A.

2008-01-01T23:59:59.000Z

123

Ultrafast Laser Induced Thermo-Elasto-Visco-Plastodynamics in Single Crystalline Silicon  

E-Print Network (OSTI)

A comprehensive model for describing the fundamental mechanism dictating the interaction of ultrafast laser pulse with single crystalline silicon wafer is formulated. The need for establishing the feasibility of employing lasers of subpicosecond pulse width in Laser Induced Stress Waves Thermometry (LISWT) for single crystalline silicon processing motivated the work. The model formulation developed is of a hyperbolic type capable of characterizing non-thermal melting and thermo-elastoviscoplastic deformation as functions of laser input parameters and ambient temperature. A plastic constitutive law is followed to describe the complex elasto-viscoplastic responses in silicon undergoing Rapid Thermal Processing (RTP) annealing at elevated temperatures. A system of nine first-order hyperbolic equations applicable to describing 3-D elasto-viscoplastic wave motions in silicon is developed. The group velocities of certain selected frequency components are shown to be viable thermal indicators, thus establishing the feasibility of exploiting nanosecond laser induced propagating stress waves for the high-resolution thermal profiling of silicon wafers. Femtosecond laser induced transport dynamics in silicon is formulated based on the relaxation-time approximation of the Boltzmann equation. Temperature-dependent multi-phonons, free-carrier absorptions, and the recombination and impact ionization processes governing the laser model and carrier numbers are considered using a set of balance equations. The balance equation of lattice energy and equations of motion of both parabolic and hyperbolic types are derived to describe the complex thermo-elastoplastodynamic behaviors of the material in response to ultrafast laser pulsing. The solution strategy implemented includes a multi-time scale axisymmetric model of finite geometry and a staggered-grid finite difference scheme that allows both velocity and stress be simultaneously determined without having to solve for displacements. Transport phenomena initiated by femtosecond pulses including the spatial and temporal evolutions of electron and lattice temperatures, along with electron-hole carrier density, are found to be functions of laser fluence and pulse width. The femtosecond laser heating model that admits hyperbolic energy transport is shown to remedy the dilemma that thermal disturbances propagate with infinite speed. Non-thermal melting fluence is examined favorably against published experimental data. That it is feasible to explore femtosecond laser induced displacement and stress components for 1K resolution thermal profiling is one of the conclusions reached.

Qi, Xuele

2009-12-01T23:59:59.000Z

124

Cd1-xMnxTe semimagnetic semiconductors for ultrafast spintronics and magnetooptics  

Science Conference Proceedings (OSTI)

We present ultrafast optical characterization of Cd1-xMnxTe single crystals with high (x>0.5-Mn) concentration, studied by magnetooptical sampling and time-resolved magnetization modulation spectroscopy. We have demonstrated that ...

R. Rey-de-Castro; Daozhi Wang; A. Verevkin; A. Mycielski; R. Sobolewski

2005-01-01T23:59:59.000Z

125

Studies of third-order nonlinearities in materials and devices for ultrafast lasers  

E-Print Network (OSTI)

Recent developments in telecommunications, frequency metrology, and medical imaging have motivated research in ultrafast optics. Demand exists for broadband components and sources as well as highly nonlinear fibers and ...

Gopinath, Juliet Tara, 1976-

2005-01-01T23:59:59.000Z

126

Electromagnetically-driven ultra-fast tool servos for diamond turning  

E-Print Network (OSTI)

This thesis presents the design, implementation, and control of a new class of fast tool servos (FTS). The primary thesis contributions include the design and experimental demonstration of: novel ultra-fast electromagnetic ...

Lu, Xiaodong, Ph. D. Massachusetts Institute of Technology

2005-01-01T23:59:59.000Z

127

Ultrafast laser ablation of gold thin film targets  

Science Conference Proceedings (OSTI)

Ultrafast laser ablation of a gold thin film is studied and compared with that of a bulk target, with particular emphasis given to the process of nanoparticles generation. The process is carried out in a condition where a single laser shot removes all the irradiated film spot. The experimental results evidence interesting differences and, in particular, a reduction of the nanoparticles size, and a narrowing of a factor two of their size distribution in the case of ablation of a thin film target, a feature which we relate to a more uniform heating of the target material. We thus show that ultrashort laser ablation of thin films provides a promising way of controlling plume features and nanoparticles size.

Amoruso, S.; Ausanio, G.; Bruzzese, R. [Dipartimento di Scienze Fisiche, Universita degli Studi di Napoli Federico II, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Napoli (Italy); CNR-SPIN, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Napoli (Italy); Nedyalkov, N. N.; Atanasov, P. A. [Institute of Electronics, Bulgarian Academy of Sciences, 72 Tsaridradsko shose Boulevard, Sofia 1784 (Bulgaria); Wang, X. [CNR-SPIN, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Napoli (Italy)

2011-12-15T23:59:59.000Z

128

Calculation of Solvation Free Energies of Charged Solutes Using Mixed Cluster/Continuum Vyacheslav S. Bryantsev, Mamadou S. Diallo,, and William A. Goddard III*,  

E-Print Network (OSTI)

Calculation of Solvation Free Energies of Charged Solutes Using Mixed Cluster/Continuum Models methodologies make systematic errors in the computed free energies because of the incorrect accounting consideration. We analyze two different thermodynamic cycles for calculating the solvation free energies

Goddard III, William A.

129

J. Phys. Chem. 1994, 98, 5113-5111 5773 Free Energy of Solvation, Interaction, and Binding of Arbitrary Charge Distributions Imbedded in  

E-Print Network (OSTI)

J. Phys. Chem. 1994, 98, 5113-5111 5773 Free Energy of Solvation, Interaction, and Binding in a continuum solvent. Background Attempts seeking analytical solutions to the hydration free energies solvation free energies of arbitrary charge distributions with an overall spherical symmetry. This theory

Jayaram, Bhyravabotla

130

A QM/MM Study on the Aqueous Solvation of the Tetrahydroxouranylate [UO?(OH)?]²? Complex Ion  

SciTech Connect

We report a QM augmented QM/MM study on the coordination of the tetrahydroxouranylate ion in aqueous solution. QM/MM geometry optimizations followed by full QM single-point calculations on the optimized structures show that a hexa-coordinated structure is more stable than the hepta-coordinated structure by 43 kJ/mol. Charge transfer of the tetrahydroxouranylate to the solvating water molecules is relatively modest, and can be modeled by including a solvation layer consisting of 12 explicit water molecules.

Infante, Ivan A.; van Stralen, Bas; Visscher, Lucas

2006-01-01T23:59:59.000Z

131

Upgrading Methane Using Ultra-Fast Thermal Swing Adsorption  

Science Conference Proceedings (OSTI)

The purpose of this project is to design and demonstrate an approach to upgrade low-BTU methane streams from coal mines to pipeline-quality natural gas. The objective of Phase I of the project was to assess the technical feasibility and cost of upgrading low-BTU methane streams using ultra-fast thermal swing adsorption (TSA) using Velocys modular microchannel process technology. The objective of Phase II is to demonstrate the process at the bench-scale. Natural gas upgrading systems have six main unit operations: feed compressor, dehydration unit, nitrogen rejection unit, deoxygenator, carbon dioxide scrubber, and a sales compressor. The NRU is the focus of the development program, and a bench-scale demonstration has been initiated. The Velocys NRU system targets producing methane with greater than 96% purity and at least 90% recovery for final commercial operation. A preliminary cost analysis of the methane upgrading system, including the Velocys NRU, suggests that costs below $2.00 per million (MM) BTU methane may be achieved. The cost for a conventional methane upgrading system is well above $2.30 per MM BTU, as benchmarked in an Environmental Protection Agency study. The project is on schedule and on budget. Task 4, a bench-scale demonstration of the ultra-fast TSA system is complete. Rapid thermal swing of an adsorbent bed using microchannels has been successfully demonstrated and the separation of a 70% methane and 30% nitrogen was purified to 92% methane. The bench-scale demonstration unit was small relative to the system dead volume for the initial phase of experiments and a purge step was added to sweep the dead volume prior to desorbing the bed and measuring purity. A technical and economic feasibility assessment was completed in Task 3. The proposed Velocys technology appears feasible for the methane upgrading market. Evaluated categories include adsorbent selection, rapid-cycle valve selection, microchannel manufacturability assessment, and system design and cost. The selected adsorbent, granular microporous carbon from either Barnaby-Sutcliffe or Calgon, experimentally demonstrated sufficient methane capacity under differential temperature at 100 pounds per square inch gauge. Several valve options were identified, including candidates that can operate millions of cycles between refurbishment. The microchannel adsorber and desorber designs were made using internal Velocys manufacturability standards, and the associated costs are acceptable as included with the complete nitrogen rejection unit (NRU) cost projection. A system design and cost estimate was completed for the NRU section of the methane upgrading system. As integrated into the complete system, the cost is in line with the market requirement.

Anna Lee Tonkovich

2005-07-01T23:59:59.000Z

132

Analytical free energy second derivatives with respect to nuclear coordinates: Complete formulation for electrostatic continuum solvation models  

Science Conference Proceedings (OSTI)

We present the theory and the implementation of analytical free energy second derivatives with respect to nuclear displacements for a molecular solute described within the framework of the polarizable continuum model. The formulation applies to a cavity with an accurately modeled molecular shape and it permits a complete consideration of all aspects of the solvation model. In particular

B. Mennucci; R. Cammi; J. Tomasi

1999-01-01T23:59:59.000Z

133

Towards understanding initiation reactions of explosives via ultrafast laser quantum control  

SciTech Connect

Optimal control can be utilized to control the initiation reaction of explosives, where time dependent phase shaped electric fields drive the chemical systems towards a desired state. For quantum controlled initiation (QCI) of explosives a pulse is created which seeks to achieve initiation by employing shaped ultraviolet light. QCI will enhance the understanding of energetic material reactions by yielding insight into the characteristics, such as critical 'hot spot' size and reaction dynamics, necessary for initiation. Quantum control experiments require the ability to: (1) phase and amplitude shape an ultrafast laser pulse, (2) measure the effect of pulse shape, and (3) optimize the desired outcome. Pulse shaping is performed with a 4-focal length dispersed fused silica acousto-optic modulator (AOM) at 400 nm in the ultraviolet (UV). Transient absorption spectroscopy is used to measure the pulse shape effects. Both global and local optimization search routines such as genetic algorithm, differential evolution, and downhill simplex are used to search for the optimal pulse shape. Hexanitroazobenzene (HNAB), Trinitroanaline (TNA) and Diaminoazozyfurazan (DAAF) are excited to the first electronic state with 400 nm light. Our initiation experiments are studying the effect of phase shaped 400 nm pulses on HNAB, TNA and DAAF. Novel transient absorption spectra for each material have been obtained and note worthy regions further investigated with single parameter control (second order spectral phase and energy). Many systems have simple intensity control such as that shown by DAAF. TNA and HNAB have spectral features that are not single parameter driven and are being further investigated with complex control.

Greenfield, Margo T [Los Alamos National Laboratory; Mc Grane, Shawn D [Los Alamos National Laboratory; Moore, David S [Los Alamos National Laboratory; Scharff, R. Jason [Los Alamos National Laboratory

2010-12-08T23:59:59.000Z

134

Extension - Upgrading Methane Using Ultra-Fast Thermal Swing Adsorption  

Science Conference Proceedings (OSTI)

The need for cost effective technologies for upgrading coal mine methane to pipeline quality natural gas is becoming ever greater. The current work presents and investigates a new approach to reduce the impact of the most costly step in the conventional technology, nitrogen rejection. The proposed approach is based on the Velocys microchannel platform, which is being developed to commercialize compact and cost efficient chemical processing technology. For this separation, ultra fast thermal swing sorption is enabled by the very high rates of heat and mass transfer inherent in microchannel processing. In a first phase of the project solid adsorbents were explored. Feasibility of ultrafast thermal swing was demonstrated but the available adsorbents had insufficient differential methane capacity to achieve the required commercial economics. In a second phase, ionic liquids were adopted as absorbents of choice, and experimental work and economic analyses, performed to gauge their potential, showed promise for this novel alternative. Final conclusions suggest that a combination of a required cost target for ionic liquids or a methane capacity increase or a combination of both is required for commercialization.

Anna Lee Tonkovich

2008-08-11T23:59:59.000Z

135

Ultrafast x-ray diagnostics for laser fusion experiments  

SciTech Connect

Temporally, spectrally, and spatially resolved x-ray emission diagnostics are important tools in the study of the heating and compression of laser fusion targets by sub-nanosecond laser pulses. The use of the Livermore 15 psec resolution x-ray streak camera to make such measurements is reviewed. Temporal histories of spectrally resolved x-ray emission in the 1 to 10 keV range have been obtained. These data have served to further define the x-ray streak camera as a quantative diagnostic tool and have also provided data relating to the absorption and compression phases of laser heating. The x-ray streak camera has been used in conjunction with a specially designed pinhole imaging system to temporally record images of laser compressed targets with a spatial resolution of approximately 6 ..mu..m. Implosion characteristics are presented for experiments with glass microshell targets. The concept, development, and testing of an ultrafast framing camera for full two-dimensional time resolved imaging is discussed. A prototype camera, based on the image dissection-restoration concept, has achieved an approximately 200 psec frame period with a resolution of 50 ..mu..m.

Coleman, L.W.

1976-08-16T23:59:59.000Z

136

Ultrafast optical manipulation of atomic arrangements in chalcogenide alloy memory materials  

E-Print Network (OSTI)

A class of chalcogenide alloy materials that shows significant changes in optical properties upon an amorphous-to-crystalline phase transition has lead to development of large data capacities in modern optical data storage. Among chalcogenide phase-change materials, Ge2Sb2Te5 (GST) is most widely used because of its reliability. We use a pair of femtosecond light pulses to demonstrate the ultrafast optical manipulation of atomic arrangements from tetrahedral (amorphous) to octahedral (crystalline) Ge-coordination in GST superlattices. Depending on the parameters of the second pump-pulse, ultrafast nonthermal phase-change occurred within only few-cycles (~ 1 ps) of the coherent motion corresponding to a GeTe4 local vibration. Using the ultrafast switch in chalcogenide alloy memory could lead to a major paradigm shift in memory devices beyond the current generation of silicon-based flash-memory.

Makino, Kotaro; Hase, Muneaki

2011-01-01T23:59:59.000Z

137

Ultrafast Supercontinuum Spectroscopy of Carrier Multiplication and Biexcitonic Effects in Excited States of PbS Quantum Dots  

SciTech Connect

We examine the population dynamics of multiple excitons in PbS quantum dots using spectrally resolved ultrafast supercontinuum transient absorption (SC-TA) measurements. We simultaneously probe the first three excitonic transitions. The transient spectra show the presence of bleaching of absorption for the 1S{sub h}-1S{sub e} transition, as well as transients associated with the 1P{sub h}-1P{sub e} transition. We examine signatures of carrier multiplication (multiple excitons arising from a single absorbed photon) from analysis of the bleaching features in the limit of low absorbed photon numbers (dynamics shows that bleaching associated with biexciton population is red shifted with respect to the single exciton feature, which is in accordance with a positive binding energy for the biexciton.

Sfeir M. Y.; Gesuele, F.; Koh, W.-K.; Murray, C.B.; Heinz, T.F.; Wong, C.W.

2012-06-01T23:59:59.000Z

138

Solvated electron yields in liquid and supercritical ammonia-A statistical mechanical treatment  

Science Conference Proceedings (OSTI)

Earlier the geminate recombination of ions and solvated electrons, produced by ionizing radiation or laser light, was theoretically treated by a model which consisted of a Rydberg atom interacting with the thermodynamic fluctuations of the medium [R. Schiller, J. Chem. Phys. 92, 5527 (1990)]. The theory was applied to liquid-to-supercritical water [R. Schiller and A. Horvath, J. Chem. Phys. 135, 084510 (2011)]. Now it is compared with recent experiments performed on liquid-to-supercritical ammonia [J. Urbanek, A. Dahmen, J. Torres-Alacan, P. Koenigshoven, J. Lindner, and P. Voehringer, J. Phys. Chem. B 116, 2223 (2012)]. The agreement between theory and experiment seems to be reasonable. The treatment is critically assessed.

Schiller, Robert; Horvath, Akos [Centre for Energy Research, P.O.B. 49, Budapest H-1525 (Hungary)

2012-12-07T23:59:59.000Z

139

Population-split genetic algorithm for retrieval of ultrafast laser parameters  

Science Conference Proceedings (OSTI)

Authors modify the traditional or standard genetic algorithm by splitting the initial population. This crucial step is an imitation of sexual and asexual reproduction mechanism in the life cycle of many plants or animals. Asexual reproduction shall happen ... Keywords: frequency resolved optical gating, genetic algorithm, pulse retrieving, ultrafast lasers

S. F. Shu; C. L. Pan; C. T. Sun

2003-09-01T23:59:59.000Z

140

Simulations of ultra-fast precessional switching of AFC thin film storage media  

Science Conference Proceedings (OSTI)

Micromagnetic simulations of the application of perpendicular field pulses to in-plane antiferromagnetically coupled (AFC) thin film disk media have been performed. Starting from a thermally relaxed state, application of a perpendicular field pulse to ... Keywords: Antiferromagnetically coupled media, Magnetic recording, Micromagnetic simulation, Ultrafast magnetization reversal

James J. Jin; David McA. McKirdy; Jim J. Miles; Roy W. Chantrell

2006-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "ultrafast solvation dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

A graph theoretic approach to ultrafast information distribution: Borel Cayley graph resizing algorithm  

Science Conference Proceedings (OSTI)

A graph theoretic approach is proposed to formulate communication graphs that enable ultrafast information distribution. In our earlier work, we reported that Borel Cayley graph (BCG) is a promising candidate as a logical topology for fast information ... Keywords: Borel Cayley graph, Cayley graph, Graph theory, Interconnection networks, Network modeling

Jaewook Yu; Eric Noel; K. Wendy Tang

2010-11-01T23:59:59.000Z

142

Ultrafast shift and injection currents observed in wurtzite semiconductors via emitted terahertz radiation  

E-Print Network (OSTI)

and injection currents have been generated in bulk GaAs and strained GaAs quantum wells QWs , respectivelyUltrafast shift and injection currents observed in wurtzite semiconductors via emitted terahertz; published online 18 November 2005 Shift and injection currents are generated in the wurtzite semiconductors

Van Driel, Henry M.

143

Theoretical and Experimental Characterization of the Ultrafast Aircraft Thermometer: Reduction of Aerodynamic Disturbances and Signal Processing  

Science Conference Proceedings (OSTI)

The ultrafast aircraft thermometer, built for measuring temperature in clouds at flight speeds up to 100 m?s?1, employs a 2.5-?m-thick platinum-coated tungsten wire as a sensing element. When temperature increases, the wire resistance increases. ...

Bogdan Rosa; Konrad Bajer; Krzysztof E. Haman; Tomasz Szoplik

2005-07-01T23:59:59.000Z

144

DEVELOPMENT OF NEW MID-INFRARED ULTRAFAST LASER SOURCES FOR COMPACT COHERENT X-RAY SOURCES  

SciTech Connect

In this project, we proposed to develop laser based mid-infrared lasers as a potentially robust and reliable source of ultrafast pulses in the mid-infrared region of the spectrum, and to apply this light source to generating bright, coherent, femtosecond-to-attosecond x-ray beams.

Sterling Backus

2012-05-14T23:59:59.000Z

145

Ultrafast tracking electronics for the ATLAS trigger at the CERN Large Hadron Collider  

E-Print Network (OSTI)

FTK Ultrafast tracking electronics for the ATLAS trigger at the CERN Large Hadron Collider Italy challenge at a hadron collider is determining what a new phenomenon is. Higgs, SUSY, KK excitations, Z of decay products multiple decay modes couplings to other particles · For each of these, large samples

146

Upgrading Methane Using Ultra-Fast Thermal Swing Adsorption  

Science Conference Proceedings (OSTI)

The purpose of this project is to design and demonstrate an approach to upgrade low-BTU methane streams from coal mines to pipeline-quality natural gas. The objective of Phase I of the project was to assess the technical feasibility and cost of upgrading low-BTU methane streams using ultra-fast thermal swing adsorption (TSA) using Velocys modular microchannel process technology. The objective of Phase II is to demonstrate the process at the bench scale. The project is on schedule and on budget. A technical and economic feasibility assessment was completed in Task 3. The proposed Velocys technology appears feasible for the methane upgrading market. Evaluated categories include adsorbent selection, rapid-cycle valve selection, microchannel manufacturability assessment, and system design and cost. The selected adsorbent, granular microporous carbon from either Barnaby-Sutcliffe or Calgon, experimentally demonstrated sufficient methane capacity under differential temperature at 100 pounds per square inch gauge. Several valve options were identified, including candidates that can operate millions of cycles between refurbishment. The microchannel adsorber and desorber designs were made using internal Velocys manufacturability standards, and the associated costs are acceptable as included with the complete nitrogen rejection unit (NRU) cost projection. A system design and cost estimate was completed for the NRU section of the methane upgrading system. As integrated into the complete system, the cost is in line with the market requirement. The system has six main unit operations: feed compressor, dehydration unit, nitrogen rejection unit, deoxygenator, carbon dioxide scrubber, and a sales compressor. The NRU is the focus of the development program, and a bench-scale demonstration will be initiated in the next fiscal year. The Velocys NRU system targets producing methane with greater than 96% purity and at least 90% recovery for final commercial operation. A preliminary cost analysis of the methane upgrading system, including the Velocys NRU, suggests that costs below $2.00 per million (MM) BTU methane may be achieved. The cost for a conventional methane upgrading system is well above $2.30 per MM BTU, as benchmarked in an Environmental Protection Agency study.

Anna Lee Tonkovich

2004-07-01T23:59:59.000Z

147

Time-domain sampling of x-ray pulses using an ultrafast sample response  

Science Conference Proceedings (OSTI)

We employ the ultrafast response of a 15.4 nm thin SrRuO{sub 3} layer grown epitaxially on a SrTiO{sub 3} substrate to perform time-domain sampling of an x-ray pulse emitted from a synchrotron storage ring. Excitation of the sample with an ultrashort laser pulse triggers coherent expansion and compression waves in the thin layer, which turn the diffraction efficiency on and off at a fixed Bragg angle during 5 ps. This is significantly shorter than the duration of the synchrotron x-ray pulse of 100 ps. Cross-correlation measurements of the ultrafast sample response and the synchrotron x-ray pulse allow to reconstruct the x-ray pulse shape.

Gaal, P.; Shayduk, R. [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Wilhelm-Conrad-Roentgen Campus, BESSY II, Albert-Einstein-Str. 15, 12489 Berlin (Germany); Schick, D.; Herzog, M.; Bojahr, A.; Goldshteyn, J.; Navirian, H. A.; Leitenberger, W. [Institut fuer Physik und Astronomie, Universitaet Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam (Germany); Vrejoiu, I. [Max-Planck-Institut fuer Mikrostrukturphysik, Weinberg 2, 06120 Halle (Germany); Khakhulin, D.; Wulff, M. [European Synchrotron Radiation Facility (ESRF), 6 rue Jules Horowitz, 38000 Grenoble (France); Bargheer, M. [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Wilhelm-Conrad-Roentgen Campus, BESSY II, Albert-Einstein-Str. 15, 12489 Berlin (Germany); Institut fuer Physik und Astronomie, Universitaet Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam (Germany)

2012-12-10T23:59:59.000Z

148

DeepNet: An Ultrafast Neural Learning Code for Seismic Imaging  

SciTech Connect

A feed-forward multilayer neural net is trained to learn the correspondence between seismic data and well logs. The introduction of a virtual input layer, connected to the nominal input layer through a special nonlinear transfer function, enables ultrafast (single iteration), near-optimal training of the net using numerical algebraic techniques. A unique computer code, named DeepNet, has been developed, that has achieved, in actual field demonstrations, results unattainable to date with industry standard tools.

Barhen, J.; Protopopescu, V.; Reister, D.

1999-07-10T23:59:59.000Z

149

Potential for ultrafast dynamic chemical imaging with few-cycle infrared lasers  

E-Print Network (OSTI)

We studied the photoelectron spectra generated by an intense few-cycle infrared laser pulse. By focusing on the angular distributions of the back rescattered high energy photoelectrons, we show that accurate differential elastic scattering cross sections of the target ion by free electrons can be extracted. Since the incident direction and the energy of the free electrons can be easily changed by manipulating the laser's polarization, intensity, and wavelength, these extracted elastic scattering cross sections, in combination with more advanced inversion algorithms, may be used to reconstruct the effective single-scattering potential of the molecule, thus opening up the possibility of using few-cycle infrared lasers as powerful table-top tools for imaging chemical and biological transformations, with the desired unprecedented temporal and spatial resolutions.

Morishita, T; Chen, Z; Lin, C D

2007-01-01T23:59:59.000Z

150

Ultrafast Strong-Field Vibrational Dynamics Studied by Femtosecond Extreme-Ultraviolet Transient Absorption Spectroscopy  

E-Print Network (OSTI)

difference in dispersion caused by the inert gas between thespectral dispersion employing the VCR semi-infinite gasspectral dispersion employing the VCR semi-infinite gas

Hosler, Erik Robert

2013-01-01T23:59:59.000Z

151

Synthesis, Characterization, and Ultrafast Dynamics of Metal, Metal Oxide, and Semiconductor Nanomaterials  

E-Print Network (OSTI)

application in the lithium ion battery, and magnetic andApplication in the Lithium Ion Battery, and Magnetic and

Wheeler, Damon Andreas

2013-01-01T23:59:59.000Z

152

Ultrafast dynamics of excitons and charges in organic materials and semiconductor nanocrystals  

E-Print Network (OSTI)

and electronic properties that are of interest for applications in e.g. solar cells, photodiodes, light- emitting diodes, field-effect transistors and nanoscale molecular electronics. We studied the mechanism of charge

Schuster, Assaf

153

Real-Time Observation of Cuprates Structural Dynamics by Ultrafast Electron Crystallography  

E-Print Network (OSTI)

The phonon-mediated attractive interaction between carriers leads to the Cooper pair formation in conventional superconductors. Despite decades of research, the glue holding Cooper pairs in high-temperature superconducting ...

Carbone, F.

154

Particle beam dynamics | Princeton Plasma Physics Lab  

NLE Websites -- All DOE Office Websites (Extended Search)

Particle beam dynamics Particle beam dynamics Subscribe to RSS - Particle beam dynamics The study of the physics of charged particle beams and the accelerators that produce them. This cross-disciplinary area intersects with fields such as plasma physics, high-energy density science, and ultra-fast lasers. Premiere issue of "Quest" magazine details PPPL's strides toward fusion energy and advances in plasma science Quest Magazine Summer 2013 Welcome to the premiere issue of Quest, the annual magazine of the U.S. Department of Energy's Princeton Plasma Physics Laboratory (PPPL). Read more about Premiere issue of "Quest" magazine details PPPL's strides toward fusion energy and advances in plasma science Ronald C Davidson Ronald Davidson heads PPPL research on charged particle beam dynamics and

155

The Behavior of Hydrogen Under Extreme Conditions on Ultrafast Timescales (A "Life at the Frontiers of Energy Research" contest entry from the 2011 Energy Frontier Research Centers (EFRCs) Summit and Forum)  

DOE Green Energy (OSTI)

'The Behavior of Hydrogen Under Extreme Conditions on Ultrafast Timescales ' was submitted by the Center for Energy Frontier Research in Extreme Environments (EFree) to the 'Life at the Frontiers of Energy Research' video contest at the 2011 Science for Our Nation's Energy Future: Energy Frontier Research Centers (EFRCs) Summit and Forum. Twenty-six EFRCs created short videos to highlight their mission and their work. EFree is directed by Ho-kwang Mao at the Carnegie Institute of Washington and is a partnership of scientists from thirteen institutions.The Office of Basic Energy Sciences in the U.S. Department of Energy's Office of Science established the 46 Energy Frontier Research Centers (EFRCs) in 2009. These collaboratively-organized centers conduct fundamental research focused on 'grand challenges' and use-inspired 'basic research needs' recently identified in major strategic planning efforts by the scientific community. The overall purpose is to accelerate scientific progress toward meeting the nation's critical energy challenges. The mission of Energy Frontier Research in Extreme Environments is 'to accelerate the discovery and creation of energy-relevant materials using extreme pressures and temperatures.' Research topics are: catalysis (CO{sub 2}, water), photocatalysis, solid state lighting, optics, thermelectric, phonons, thermal conductivity, solar electrodes, fuel cells, superconductivity, extreme environment, radiation effects, defects, spin dynamics, CO{sub 2} (capture, convert, store), greenhouse gas, hydrogen (fuel, storage), ultrafast physics, novel materials synthesis, and defect tolerant materials.

Mao, Ho-kwang (Director, Center for Energy Frontier Research in Extreme Environments); EFree Staff

2011-05-01T23:59:59.000Z

156

The H2O2+OH ? HO2+H2O reaction in aqueous solution from a charge-dependent continuum model of solvation  

Science Conference Proceedings (OSTI)

We applied our recently developed protocol of the conductor-like continuum model of solvation to describe the title reaction in aqueous solution. The model has the unique feature of the molecular cavity being dependent on the atomic charges in the solute, and can be extended naturally to transition states and reaction pathways. It was used to calculate the reaction energetics and reaction rate in solution for the title reaction. The rate of reaction calculated using canonical variational transition state theory CVT in the context of the equilibrium solvation path (ESP) approximation, and including correction for tunneling through the small curvature approximation (SCT) was found to be 3.6 106 M-1 s-1, in very good agreement with experiment, These results suggest that the present protocol of the conductor-like continuum model of solvation with the charge-dependent cavity definition captures accurately the solvation effects at transition states and allows for quantitative estimates of reaction rates in solutions. This work was supported by the U.S. Department of Energy's (DOE) Office of Basic Energy Sciences, Chemical Sciences program. The Pacific Northwest National Laboratory is operated by Battelle for DOE.

Ginovska, Bojana; Camaioni, Donald M.; Dupuis, Michel

2008-07-07T23:59:59.000Z

157

Microsoft PowerPoint - WishartUltrafastAccelFinal.ppt [Read-Only]  

NLE Websites -- All DOE Office Websites (Extended Search)

June 25-28, 2004 Chemistry Department Brookhaven National Laboratory LEAF LEAF Office of Basic Energy Sciences U.S. Department of Energy Advanced Energy Systems 2 Tabata Meeting and Satellite Symposia March 10 and 11, 2000 "New Applications and Facilities of Radiation on Radiation Chemistry, Material Science, And Radiation Biology for Future Radiation Science and Technology" Osaka University Institute of Scientific and Industrial Research, Osaka March 13 - 17, 2000 "International Symposium on Prospects for Application of Radiation Towards the 21st Century" Waseda University, Tokyo March 20, 2000 "Development of Ultrafast Detection Systems for Radiation Chemistry" Univ. of Tokyo Nuclear Engineering Research Laboratory in Tokai-Mura The Brookhaven LEAF

158

Polymer–Graphene Nanocomposites as Ultrafast-Charge and -Discharge Cathodes for Rechargeable Lithium Batteries  

Science Conference Proceedings (OSTI)

Electroactive polymers are a new generation of 'green' cathode materials for rechargeable lithium batteries. We have developed nanocomposites combining graphene with two promising polymer cathode materials, poly(anthraquinonyl sulfide) and polyimide, to improve their high-rate performance. The polymer-graphene nanocomposites were synthesized through a simple in-situ polymerization in the presence of graphene sheets. The highly dispersed graphene sheets in the nanocomposite drastically enhanced the electronic conductivity and allowed the electrochemical activity of the polymer cathode to be efficiently utilized. This allows for ultrafast charging and discharging - the composite can deliver more than 100 mAh/g within just a few seconds.

Song, Zhiping; Xu, Terrence (Tianren); Gordin, Mikhail; Jiang, Yingbing; Bae, In-Tae; Xiao, Qiangfeng; Zhan, Hui; Liu, Jun; Wang, Donghai

2012-05-09T23:59:59.000Z

159

Ultrafast laser based coherent control methods for explosives detection  

SciTech Connect

The detection of explosives is a notoriously difficult problem, especially at stand-off, due to their (generally) low vapor pressure, environmental and matrix interferences, and packaging. We are exploring Optimal Dynamic Detection of Explosives (ODD-Ex), which exploits the best capabilities of recent advances in laser technology and recent discoveries in optimal shaping of laser pulses for control of molecular processes to significantly enhance the standoff detection of explosives. The core of the ODD-Ex technique is the introduction of optimally shaped laser pulses to simultaneously enhance sensitivity to explosives signatures while dramatically improving specificity, particularly against matrix materials and background interferences. These goals are being addressed by operating in an optimal non-linear fashion, typically with a single shaped laser pulse inherently containing within it coherently locked control and probe subpulses. Recent results will be presented.

Moore, David Steven [Los Alamos National Laboratory

2010-12-06T23:59:59.000Z

160

Magnetic soft x-ray microscopy-imaging fast spin dynamics inmagnetic nanostructures  

SciTech Connect

Magnetic soft X-ray microscopy combines 15nm spatial resolution with 70ps time resolution and elemental sensitivity. Fresnel zone plates are used as X-ray optics and X-ray magnetic circular dichroism serves as magnetic contrast mechanism. Thus scientifically interesting and technologically relevant low dimensional nanomagnetic systems can be imaged at fundamental length and ultrafast time scales in a unique way. Studies include magnetization reversal in magnetic multilayers, nanopatterned systems, vortex dynamics in nanoelements and spin current induced phenomena.

Fischer, Peter; Kim, Dong-Hyun; Mesler, Brooke L.; Chao, Weilun; Sakdinawat, Anne E.; Anderson, Erik H.

2007-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "ultrafast solvation dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

H.sub.2O doped WO.sub.3, ultra-fast, high-sensitivity hydrogen sensors  

DOE Patents (OSTI)

An ultra-fast response, high sensitivity structure for optical detection of low concentrations of hydrogen gas, comprising: a substrate; a water-doped WO.sub.3 layer coated on the substrate; and a palladium layer coated on the water-doped WO.sub.3 layer.

Liu, Ping (Denver, CO); Tracy, C. Edwin (Golden, CO); Pitts, J. Roland (Lakewood, CO); Lee, Se-Hee (Lakewood, CO)

2011-03-22T23:59:59.000Z

162

2011 Dynamics at Surfaces Gordon Research Conference (August 7-12, 2011, Salve Regina University, Newport, Rhode Island)  

SciTech Connect

The 2011 Gordon Conference on Dynamics at Surfaces is the 32nd anniversary of a meeting held every two years that is attended by leading researchers in the area of experimental and theoretical dynamics at liquid and solid surfaces. The conference focuses on the dynamics of the interaction of molecules with either liquid or solid surfaces, the dynamics of the outermost layer of liquid and solid surfaces and the dynamics at the liquid-solid interface. Specific topics that are featured include state-to-state scattering dynamics, chemical reaction dynamics, non-adiabatic effects in reactive and inelastic scattering of molecules from surfaces, single molecule dynamics at surfaces, surface photochemistry, ultrafast dynamics at surfaces, and dynamics at water interfaces. The conference brings together investigators from a variety of scientific disciplines including chemistry, physics, materials science, geology, biophysics, and astronomy.

Greg Sitz

2011-08-12T23:59:59.000Z

163

Princeton Plasma Physics Lab - Particle beam dynamics  

NLE Websites -- All DOE Office Websites (Extended Search)

particle-beam-dynamics The study of particle-beam-dynamics The study of the physics of charged particle beams and the accelerators that produce them. This cross-disciplinary area intersects with fields such as plasma physics, high-energy density science, and ultra-fast lasers. en Premiere issue of "Quest" magazine details PPPL's strides toward fusion energy and advances in plasma science http://www.pppl.gov/news/2013/09/premiere-issue-quest-magazine-details-pppls-strides-toward-fusion-energy-and-advances-0

164

Final Report: X-ray Studies of Materials Dynamics at MHATT-CAT Sector 7 , Advanced Photon Source  

SciTech Connect

This Final Report describes the scientific accomplishments that have been achieved with support from grant DE-FG02-03ER46023 during the period 12/01/02 ? 11/30/05. The funding supported a vigorous scientific program allowing the PI to achieve leadership in a number of important areas. In particular, research carried out during this period has opened way to ultrafast dynamics studies of materials by combining the capabilities of synchrotron radiation with those of ultrafast lasers. This enables the initiation of laser-induced excitations and studies of their subsequent dynamics using laser-pump/x-ray probe techniques. Examples of such excitations include phonons, shock waves, excitons, spin-waves, and polaritons. The breadth of phenomena that can now be studied in the time-domain is very broad, revealing new phenomena and mechanisms that are critical to many applications of materials.

Roy Clarke

2006-04-25T23:59:59.000Z

165

Ultrafast effective multi-level atom method for primordial hydrogen recombination  

E-Print Network (OSTI)

Cosmological hydrogen recombination has recently been the subject of renewed attention because of its importance for predicting the power spectrum of cosmic microwave background anisotropies. It has become clear that it is necessary to account for a large number n >~ 100 of energy shells of the hydrogen atom, separately following the angular momentum substates in order to obtain sufficiently accurate recombination histories. However, the multi-level atom codes that follow the populations of all these levels are computationally expensive, limiting recent analyses to only a few points in parameter space. In this paper, we present a new method for solving the multi-level atom recombination problem, which splits the problem into a computationally expensive atomic physics component that is independent of the cosmology, and an ultrafast cosmological evolution component. The atomic physics component follows the network of bound-bound and bound-free transitions among excited states and computes the resulting effectiv...

Ali-Haïmoud, Yacine

2010-01-01T23:59:59.000Z

166

An ultrafast angle-resolved photoemission apparatus for measuring complex materials  

Science Conference Proceedings (OSTI)

We present technical specifications for a high resolution time- and angle-resolved photoemission spectroscopy setup based on a hemispherical electron analyzer and cavity-dumped solid state Ti:sapphire laser used to generate pump and probe beams, respectively, at 1.48 and 5.93 eV. The pulse repetition rate can be tuned from 209 Hz to 54.3 MHz. Under typical operating settings the system has an overall energy resolution of 23 meV, an overall momentum resolution of 0.003 A{sup -1}, and an overall time resolution of 310 fs. We illustrate the system capabilities with representative data on the cuprate superconductor Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}}. The descriptions and analyses presented here will inform new developments in ultrafast electron spectroscopy.

Smallwood, Christopher L.; Lanzara, Alessandra [Department of Physics, University of California, Berkeley, California 94720 (United States); Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Jozwiak, Christopher [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Zhang Wentao [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

2012-12-15T23:59:59.000Z

167

Observing Structure and Motion in Molecules with Ultrafast Strong Field and Short Wavelength Laser Radiation  

SciTech Connect

The term "molecular movie" has come to describe efforts to track and record Angstrom-scale coherent atomic and electronic motion in a molecule. The relevant time scales for this range cover several orders of magnitude, from sub-femtosecond motion associated with electron-electron correlations, to 100-fs internal vibrations, to multi-picosecond motion associated with the dispersion and quantum revivals of molecular reorientation. Conventional methods of cinematography do not work well in this ultrafast and ultrasmall regime, but stroboscopic "pump and probe" techniques can reveal this motion with high fidelity. This talk will describe some of the methods and recent progress in exciting and controlling this motion, using both laboratory lasers and the SLAC Linac Coherent Light Source x-ray free electron laser, and will further try to relate the date to the goal of molecular movies.

Bucksbaum, Philip H

2011-04-13T23:59:59.000Z

168

Evidence for ultra-fast heating in intense-laser irradiated reduced-mass targets  

Science Conference Proceedings (OSTI)

We report on an experiment irradiating individual argon droplets of 20 {mu}m diameter with laser pulses of several Joule energy at intensities of 10{sup 19} W/cm{sup 2}. K-shell emission spectroscopy was employed to determine the hot electron energy fraction and the time-integrated charge-state distribution. Spectral fitting indicates that bulk temperatures up to 160 eV are reached. Modelling of the hot-electron relaxation and generation of K-shell emission with collisional hot-electron stopping only is incompatible with the experimental results, and the data suggest an additional ultra-fast (sub-ps) heating contribution. For example, including resistive heating in the modelling yields a much better agreement with the observed final bulk temperature and qualitatively reproduces the observed charge state distribution.

Neumayer, P.; Gumberidze, A.; Hochhaus, D. C. [ExtreMe Matter Institute EMMI and Research Division, GSI Helmholtzzentrum fuer Schwerionenforschung, 64291 Darmstadt (Germany); Frankfurt Institute for Advanced Studies FIAS, 60438 Frankfurt am Main (Germany); Aurand, B.; Stoehlker, T. [Helmholtzzentrum fuer Schwerionenforschung GSI, 64291 Darmstadt (Germany); Helmholtz Institute Jena, 07743 Jena (Germany); Costa Fraga, R. A.; Kalinin, A. [Institut fuer Kernphysik, J. W. Goethe University Frankfurt, 60438 Frankfurt am Main (Germany); Ecker, B. [Johannes Gutenberg University Mainz, 55099 Mainz (Germany); Helmholtz Institute Jena, 07743 Jena (Germany); Grisenti, R. E. [Institut fuer Kernphysik, J. W. Goethe University Frankfurt, 60438 Frankfurt am Main (Germany); Helmholtzzentrum fuer Schwerionenforschung GSI, 64291 Darmstadt (Germany); Kaluza, M. C. [Helmholtz Institute Jena, 07743 Jena (Germany); IOQ Institute of Optics and Quantum Electronics, University of Jena (Germany); Kuehl, T. [Johannes Gutenberg University Mainz, 55099 Mainz (Germany); Helmholtzzentrum fuer Schwerionenforschung GSI, 64291 Darmstadt (Germany); Helmholtz Institute Jena, 07743 Jena (Germany); Polz, J. [IOQ Institute of Optics and Quantum Electronics, University of Jena (Germany); Reuschl, R. [ExtreMe Matter Institute EMMI and Research Division, GSI Helmholtzzentrum fuer Schwerionenforschung, 64291 Darmstadt (Germany); Winters, D.; Winters, N.; Yin, Z. [Helmholtzzentrum fuer Schwerionenforschung GSI, 64291 Darmstadt (Germany)

2012-12-15T23:59:59.000Z

169

Isolated sub-100-attosecond pulse generation via controlling electron dynamics  

E-Print Network (OSTI)

A new method to coherently control the electron dynamics is proposed using a few-cycle laser pulse in combination with a controlling field. It is shown that this method not only broadens the attosecond pulse bandwidth, but also reduces the chirp, then an isolated 80-as pulse is straightforwardly obtained and even shorter pulse is achievable by increasing the intensity of the controlling field. Such ultrashort pulses allow one to investigate ultrafast electronic processes which have never be achieved before. In addition, the few-cycle synthesized pulse is expected to manipulate a wide range of laser-atom interactions.

Lan, Pengfei; Cao, Wei; Li, Yuhua; Wang, Xinlin

2007-01-01T23:59:59.000Z

170

Proceedings of "Optical Probes of Dynamics in Complex Environments"  

Science Conference Proceedings (OSTI)

This document contains the proceedings from the symposium on Optical Probes of Dynamics in Complex Environments, which organized as part of the 235th National Meeting of the American Chemical Society in New Orleans, LA from April 6 to 10, 2008. The study of molecular dynamics in chemical reaction and biological processes using time ���������������resolved spectroscopy plays an important role in our understanding of energy conversion, storage, and utilization problems. Fundamental studies of chemical reactivity, molecular rearrangements, and charge transport are broadly supported by the DOE Office of Science because of their role in the development of alternative energy sources, the understanding of biological energy conversion processes, the efficient utilization of existing energy resources, and the mitigation of reactive intermediates in radiation chemistry. In addition, time resolved spectroscopy is central to all of DOEs grand challenges for fundamental energy science. This symposium brought together leaders in the field of ultrafast spectroscopy, including experimentalists, theoretical chemists, and simulators, to discuss the most recent scientific and technological advances. DOE support for this conference was used to help young US and international scientists travel to the meeting. The latest technology in ultrafast infrared, optical, and xray spectroscopy and the scientific advances that these methods enable were covered. Particular emphasis was placed on new experimental methods used to probe molecular dynamics in liquids, solids, interfaces, nanostructured materials, and biomolecules.

Sension, R; Tokmakoff, A

2008-04-01T23:59:59.000Z

171

Extended Field of View Soft X-Ray Fourier Transform Holography: Toward Imaging Ultrafast Evolution in a Single Shot  

Science Conference Proceedings (OSTI)

Panoramic full-field imaging is demonstrated by applying spatial multiplexing to Fourier transform holography. Multiple object and reference waves extend the effective field of view for lensless imaging without compromising the spatial resolution. In this way, local regions of interest distributed throughout a sample can be simultaneously imaged with high spatial resolution. A method is proposed for capturing multiple ultrafast images of a sample with a single x-ray pulse.

Schlotter, W.F.; /Stanford U., Appl. Phys. Dept. /SLAC, SSRL; Luening, J.; /Paris, Lab Chim. Quantique /SOLEIL, Saint-Aubin /BESSY, Berlin; Rick, R.; Chen, K.; /Stanford U., Appl. Phys. Dept. /SLAC, SSRL; Scherz, A.; /SLAC, SSRL; Eisebitt, S.; Guenther, C.M.; Eberhardt, W.; /BESSY, Berlin; Hellwig, O.; /Hitachi Global Stor. Tech., San Jose; Stohr, J.; /SLAC, SSRL

2009-04-29T23:59:59.000Z

172

Ultrafast nanolaser device for detecting cancer in a single live cell.  

Science Conference Proceedings (OSTI)

Emerging BioMicroNanotechnologies have the potential to provide accurate, realtime, high throughput screening of live tumor cells without invasive chemical reagents when coupled with ultrafast laser methods. These optically based methods are critical to advancing early detection, diagnosis, and treatment of disease. The first year goals of this project are to develop a laser-based imaging system integrated with an in- vitro, live-cell, micro-culture to study mammalian cells under controlled conditions. In the second year, the system will be used to elucidate the morphology and distribution of mitochondria in the normal cell respiration state and in the disease state for normal and disease states of the cell. In this work we designed and built an in-vitro, live-cell culture microsystem to study mammalian cells under controlled conditions of pH, temp, CO2, Ox, humidity, on engineered material surfaces. We demonstrated viability of cell culture in the microsystem by showing that cells retain healthy growth rates, exhibit normal morphology, and grow to confluence without blebbing or other adverse influences of the material surfaces. We also demonstrated the feasibility of integrating the culture microsystem with laser-imaging and performed nanolaser flow spectrocytometry to carry out analysis of the cells isolated mitochondria.

Gourley, Paul Lee; McDonald, Anthony Eugene

2007-11-01T23:59:59.000Z

173

Velocity measurements in the near field of a diesel fuel injector by ultrafast imagery  

E-Print Network (OSTI)

This paper examines the velocity profile of fuel issuing from a high-pressure single-orifice diesel injector. Velocities of liquid structures were determined from time-resolved ultrafast shadow images, formed by an amplified two-pulse laser source coupled to a double-frame camera. A statistical analysis of the data over many injection events was undertaken to map velocities related to spray formation near the nozzle outlet as a function of time after start of injection. These results reveal a strong asymmetry in the liquid profile of the test injector, with distinct fast and slow regions on opposite sides of the orifice. Differences of ~100 m/s can be observed between the 'fast' and 'slow' sides of the jet, resulting in different atomization conditions across the spray. On average, droplets are dispersed at a greater distance from the nozzle on the 'fast' side of the flow, and distinct macrostructure can be observed under the asymmetric velocity conditions. The changes in structural velocity and atomization b...

Sedarsky, David

2013-01-01T23:59:59.000Z

174

Quantum Chemical Analysis of the Excited State Dynamics of Hydrated Electrons  

E-Print Network (OSTI)

Quantum calculations are performed for an anion water cluster representing the first hydration shell of the solvated electron in solution. The absorption spectra from the ground state, the instant excited states and the relaxed excited states are calculated including CI-SD interactions. Analytic expressions for the nonadiabatic relaxation are presented. It is shown that the 50fs dynamics recently observed after s->p excitation is best accounted for if it is identified with the internal conversion, preceded by an adiabatic relaxation within the excited p state. In addition, transient absorptions found in the infrared are qualitatively reproduced by these calculations .

P. O. J. Scherer; Sighart F. Fischer

2006-02-01T23:59:59.000Z

175

Probing nonequilibrium dynamics with white-light femtosecond pulses  

Science Conference Proceedings (OSTI)

Femtosecond pulsed lasers have become an invaluable tool for examining ultrafast nonequilibrium dynamics. With pulsewidths of a few hundred femtoseconds (fs) to less than 10 fs, these lasers can clearly provide unprecedented temporal resolution. By amplifying ultrashort laser pulses to sufficient levels of energy per pulse, it is possible to exploit the nonlinear optical properties of certain materials to generate extremely broadband pulses. These pulses retain the time structure of the incident pulse, but contain a spectral bandwidth extending from the infrared to as far as the ultraviolet. By generating white-light pulses, it becomes possible to probe ultrafast nonlinear processes over a large range of energies. In this paper, the process of generating white-light ultrashort pulses will be presented, along with a discussion of different probing techniques and procedures necessary for modeling the transient optical data. Finally, results from pump–probe measurements using a white-light probe on indium phosphide (InP) films will be presented as a demonstration of this technique.

John Klopf; Pam Norris

2007-05-01T23:59:59.000Z

176

Studying Nanoscale Magnetism and its Dynamics with Soft X-ray Microscopy  

Science Conference Proceedings (OSTI)

Magnetic soft X-ray microscopy allows for imaging magnetic structures at a spatial resolution down to 15nm and a time resolution in the sub-100ps regime. Inherent elemental specificity can be used to image the magnetic response of individual components such as layers in multilayered systems. This review highlights current achievements and discusses the future potential of magnetic soft X-ray microscopy at fsec X-ray sources where snapshot images of ultrafast spin dynamics with a spatial resolution below 10nm will become feasible.

Mccall, Monnikue M; Fischer, Peter

2008-05-01T23:59:59.000Z

177

The Influence of Chain Dynamics on the Far Infrared Spectrum of Liquid Methanol-Water Mixtures  

DOE Green Energy (OSTI)

Far-infrared absorption spectroscopy has been used to study the low frequency ({center_dot} 100 cm{sup -1}) intermolecular modes of methanol in mixtures with water. With the aid of a first principles molecular dynamics simulation on an equivalent system, a detailed understanding about the origin of the low frequency IR modes has been established. The total dipole spectrum from the simulation suggests that the bands appearing in the experimental spectra at approximately 55 cm{sup -1} and 70 cm{sup -1} in methanol and methanol-rich mixtures arise from both fluctuations and torsional motions occurring within the methanol hydrogen-bonded chains. The influence of these modes on both the solvation dynamics and the relaxation mechanisms in the liquid are discussed within the context of recent experimental and theoretical results that have emerged from studies focusing on the short time dynamics in the methanol hydrogen bond network.

Woods, K.N.; /Stanford U., Phys. Dept.; Wiedemann, H.; /SLAC, SSRL

2005-07-12T23:59:59.000Z

178

Applications of Ultrafast Terahertz Pulses for Intra-ExcitonicSpectroscopy of Quasi-2D Electron-Hole Gases  

Science Conference Proceedings (OSTI)

Excitons are of fundamental interest and of importance foropto-electronic applications of bulk and nano-structured semiconductors.This paper discusses the utilization of ultrafast terahertz (THz) pulsesfor the study of characteristic low-energy excitations of photoexcitedquasi 2D electron-hole (e-h) gases. Optical-pump THz-probe spectroscopyat 250-kHz repetition rate is employed to detect characteristic THzsignatures of excitons and unbound e-h pairs in GaAs quantum wells.Exciton and free-carrier densities are extracted from the data using atwo-component model. We report the detailed THz response and pairdensities for different photoexcitation energies resonant to heavy-holeexcitons, light-hole excitons, or the continuum of unbound pairs. Suchexperiments can provide quantitative insights into wavelength, time, andtemperature dependence of the low-energy response and composition ofoptically excited e-h gases in low-dimensionalsemiconductors.

Kaindl, Robert A.; Carnahan, Marc A.; Hagele, Daniel; Chemla, D.S.

2006-09-02T23:59:59.000Z

179

System and method for ultrafast optical signal detecting via a synchronously coupled anamorphic light pulse encoded laterally  

DOE Patents (OSTI)

In one general embodiment, a method for ultrafast optical signal detecting is provided. In operation, a first optical input signal is propagated through a first wave guiding layer of a waveguide. Additionally, a second optical input signal is propagated through a second wave guiding layer of the waveguide. Furthermore, an optical control signal is applied to a top of the waveguide, the optical control signal being oriented diagonally relative to the top of the waveguide such that the application is used to influence at least a portion of the first optical input signal propagating through the first wave guiding layer of the waveguide. In addition, the first and the second optical input signals output from the waveguide are combined. Further, the combined optical signals output from the waveguide are detected. In another general embodiment, a system for ultrafast optical signal recording is provided comprising a waveguide including a plurality of wave guiding layers, an optical control source positioned to propagate an optical control signal towards the waveguide in a diagonal orientation relative to a top of the waveguide, at least one optical input source positioned to input an optical input signal into at least a first and a second wave guiding layer of the waveguide, and a detector for detecting at least one interference pattern output from the waveguide, where at least one of the interference patterns results from a combination of the optical input signals input into the first and the second wave guiding layer. Furthermore, propagation of the optical control signal is used to influence at least a portion of the optical input signal propagating through the first wave guiding layer of the waveguide.

Heebner, John E. (Livermore, CA)

2010-08-03T23:59:59.000Z

180

Teasing Out the Nature of Structural Instabilities in Ceramic Compounds |  

NLE Websites -- All DOE Office Websites (Extended Search)

Doubling Estimates of Light Elements in the Earth's Core Doubling Estimates of Light Elements in the Earth's Core A New Material for Warm-White LEDs Probing Ultrafast Solvation Dynamics with High Repetition-Rate Laser/X-ray Methodologies Ultrafast X-Ray Spectroscopy as a Probe of Nonequilibrium Dynamics in Ruthenium Complexes The Electronic Origin of Photoinduced Strain Science Highlights Archives: 2013 | 2012 | 2011 | 2010 2009 | 2008 | 2007 | 2006 2005 | 2004 | 2003 | 2002 2001 | 2000 | 1998 | Subscribe to APS Science Highlights rss feed Teasing Out the Nature of Structural Instabilities in Ceramic Compounds MARCH 12, 2013 Bookmark and Share The simple perovskite structure of EuTiO3 illustrated above shows the essential competing structural instabilities. At the center of the figure is the oxygen cage rotation, and to the right is the central titanium

Note: This page contains sample records for the topic "ultrafast solvation dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Using the economics of platforms to understand the broadband-based market formation in the New Zealand Ultra-Fast Broadband Network  

Science Conference Proceedings (OSTI)

The government of New Zealand is currently building a nation-wide fibre-optics network, a project known as the Ultra-Fast Broadband (UFB) initiative. The UFB network will cover 75 percent of New Zealanders over 10 years and will cost NZD $1.5 billion ... Keywords: Cross-network effects, Layer-1 services, New Zealand broadband national initiative, Open access platform, Price structure, Two-sided platforms, Wholesale layer-2 services

Fernando BeltráN

2012-10-01T23:59:59.000Z

182

Ordered water structure at hydrophobic graphite interfaces observed by 4D, ultrafast  

E-Print Network (OSTI)

ice-substrate structure and dynamics nonequilibrium phase transition Water at interfaces femtosecond pulse, the interfacial ice assembly goes through nonequilibrium phase transformation point'' in the diffraction profiles. The ice ``melting'' time is 10 ps and the new phase grows in 20 ps

La Rosa, Andres H.

183

Water adsorption, solvation and deliquescence of alkali halide thin films on SiO2 studied by ambient pressure X-ray photoelectron spectroscopy  

Science Conference Proceedings (OSTI)

The adsorption of water on KBr thin films evaporated onto SiO2 was investigated as a function of relative humidity (RH) by ambient pressure X-ray photoelectron spectroscopy. At 30percent RH adsorbed water reaches a coverage of approximately one monolayer. As the humidity continues to increase, the coverage of water remains constant or increases very slowly until 60percent RH, followed by a rapid increase up to 100percent RH. At low RH a significant number of the Br atoms are lost due to irradiation damage. With increasing humidity solvation increases ion mobility and gives rise to a partial recovery of the Br/K ratio. Above 60percent RH the increase of the Br/K ratio accelerates. Above the deliquescence point (85percent RH), the thickness of the water layer continues to increase and reaches more than three layers near saturation. The enhancement of the Br/K ratio at this stage is roughly a factor 2.3 on a 0.5 nm KBr film, indicating a strong preferential segregation of Br ions to the surface of the thin saline solution on SiO2.

Arima, Kenta; Jiang, Peng; Deng, Xingyi; Bluhm, Henrik; Salmeron, Miquel

2010-03-31T23:59:59.000Z

184

Molecular Dynamics Simulation on the Surface Melting and ...  

Science Conference Proceedings (OSTI)

Abstract Scope, Thermal and non-thermal ultra-fast laser induced surface melting and nanojoining of Ag nanoparticles and nanowires were investigated ...

185

Optical manipulation of ultrafast electron and nuclear motion on metal surfaces  

SciTech Connect

We study the unoccupied electronic structure and dynamics of chemisorbed atoms and molecules on metal surfaces by time resolved two-photon photoemission (TR-2PP). spectroscopy, low temperature scanning tunneling microscopy (LT-STM), and theory. Our research concerns simple atomic adsorbates such as alkali and alkaline earth atoms, which provide fundamentally important models for adsorbate-surface interactions, and more complex adsorbates such as fullerenes on noble metals, which illustrate emergent interfacial properties that derive from intrinsic molecular attributes, and moleculemolecule and molecule-surface interactions. Our goal is to understand how these interactions contribute to formation of the interfacial electronic structure, and how thus formed electronic properties affect interfacial phenomena of importance to energy transduction and storage. Moreover, we explore how the interfacial electronic excitation drives dynamical phenomena such as charge transfer and surface femtochemistry.

Petek, Hrvoje

2009-12-02T23:59:59.000Z

186

Proton- and x-ray beams generated by ultra-fast CO(2) lasers for medical applications  

DOE Green Energy (OSTI)

Recent progress in using picosecond CO{sub 2} lasers for Thomson scattering and ion-acceleration experiments underlines their potentials for enabling secondary radiation- and particle-sources. These experiments capitalize on certain advantages of long-wavelength CO{sub 2} lasers, such as higher number of photons per energy unit, and favorable scaling of the electrons ponderomotive energy and critical plasma density. The high-flux x-ray bursts produced by Thomson scattering of the CO{sub 2} laser off a counter-propagating electron beam enabled high-contrast, time-resolved imaging of biological objects in the picosecond time frame. In different experiments, the laser, focused on a hydrogen jet, generated monoenergetic proton beams via the radiation-pressure mechanism. The strong power-scaling of this regime promises realization of proton beams suitable for laser-driven proton cancer therapy after upgrading the CO{sub 2} laser to sub-PW peak power. This planned improvement includes optimizing the 10-{mu}m ultra-short pulse generation, assuring higher amplification in the CO{sub 2} gas under combined isotopic- and power-broadening effects, and shortening the postamplification pulse to a few laser cycles (150-200 fs) via chirping and compression. These developments will move us closer to practical applications of ultra-fast CO{sub 2} lasers in medicine and other areas.

Pogorelsky, I.; Polyanskiy, M.; Yakimenko, V.; Ben-Zvi, I.; Shkolnikov, P. Najmudin, Z.; Palmer, C.A.J.; Dover, N.P.; Oliva, P; Carpinelli, M.

2011-07-01T23:59:59.000Z

187

Nonlinear Ultrafast Spectroscopy of Electron and Energy Transfer in Molecule Complexes  

DOE Green Energy (OSTI)

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.

Mukamel, Shaul

2006-02-09T23:59:59.000Z

188

Dislocation Dynamics  

Science Conference Proceedings (OSTI)

Mar 7, 2013 ... Recent Progress in Dislocation Dynamics: Sylvie Aubry1; Athanasios Arsenlis1; Wei Cai2; Steve Fitzgerald3; 1LLNL; 2Stanford University; ...

189

Photo-Induced Spin-State Conversion in Solvated Transition Metal Complexes Probed via Time-Resolved Soft X-ray Spectroscopy  

SciTech Connect

Solution-phase photoinduced low-spin to high-spin conversion in the FeII polypyridyl complex [Fe(tren(py)3)]2+ (where tren(py)3 is tris(2-pyridylmethyliminoethyl)amine) has been studied via picosecond soft X-ray spectroscopy. Following 1A1 --> 1MLCT (metal-to-ligand charge transfer) excitation at 560 nm, changes in the iron L2- and L3-edges were observed concomitant with formation of the transient high-spin 5T2 state. Charge-transfer multiplet calculations coupled with data acquired on low-spin and high-spin model complexes revealed a reduction in ligand field splitting of 1 eV in the high-spin state relative to the singlet ground state. A significant reduction in orbital overlap between the central Fe-3d and the ligand N-2p orbitals was directly observed, consistent with the expected ca. 0.2 Angstrom increase in Fe-N bond length upon formation of the high-spin state. The overall occupancy of the Fe-3d orbitals remains constant upon spin crossover, suggesting that the reduction in sigma-donation is compensated by significant attenuation of pi-back-bonding in the metal-ligand interactions. These results demonstrate the feasibility and unique potential of time-resolved soft X-ray absorption spectroscopy to study ultrafast reactions in the liquid phase by directly probing the valence orbitals of first-row metals as well as lighter elements during the course of photochemical transformations.

Huse, Nils; Kim, Tae Kyu; Jamula, Lindsey; McCusker, James K.; de Groot, Frank M. F.; Schoenlein, Robert W.

2010-04-30T23:59:59.000Z

190

Electron-nuclear correlations for photo-induced dynamics in molecular dimers  

E-Print Network (OSTI)

Ultrafast photoinduced dynamics of electronic excitation in molecular dimers is drastically affected by the dynamic reorganization of inter- and intra- molecular nuclear configuration modeled by a quantized nuclear degree of freedom [Cina et. al, J. Chem Phys. {118}, 46 (2003)]. The dynamics of the electronic population and nuclear coherence is analyzed by solving the chain of coupled differential equations for %mean coordinate, population inversion, electron-vibrational correlation, etc. [Prezhdo, Pereverzev, J. Chem. Phys. {113} 6557 (2000)]. Intriguing results are obtained in the approximation of a small change of the nuclear equilibrium upon photoexcitation. In the limiting case of resonance between the electronic energy gap and the frequency of the nuclear mode these results are justified by comparison to the exactly solvable Jaynes-Cummings model. It is found that the photoinduced processes in the model dimer are arranged according to their time scales: (i) fast scale of nuclear motion, (ii) intermediate scale of dynamical redistribution of electronic population between excited states as well as growth and dynamics of electron-nuclear correlation, (iii) slow scale of electronic population approach to the quasi-equilibrium distribution, decay of electron-nuclear correlation, and decrease of the amplitude of mean coordinate oscillation. The latter processes are accompanied by a noticeable growth of the nuclear coordinate dispersion associated with the overall nuclear wavepacket width. The demonstrated quantum relaxation features of the photoinduced vibronic dynamics in molecular dimers are obtained by a simple method, applicable to systems with many degrees of freedom.

Dmitri S. Kilin; Yuri V. Pereversev; Oleg V. Prezhdo

2004-03-13T23:59:59.000Z

191

Dynamics of water in the amphiphilic pore of amyloid β fibrils  

NLE Websites -- All DOE Office Websites (Extended Search)

water water in the amphiphilic pore of amyloid b fibrils q Pavan K. GhattyVenkataKrishna a,⇑ , Barmak Mostofian b a Computational Biology and Bioinformatics Group and BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA b UT/ORNL Center for Molecular Biophysics, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA a r t i c l e i n f o Article history: Available online 19 July 2013 a b s t r a c t Alzheimers disease related amyloid peptide, Ab, forms a fibrillar structure through aggregation. The aggregate is stabilized by a salt bridge that is responsible for the formation of an amphiphilic pore that can accommodate water molecules. None of the reported structures of Ab, however, contain water. We present results from molecular dynamics simulations on dimeric Ab fibrils solvated in water. Water pen- etrates and fills the amphiphilic pore increasing its volume.

192

Time-resolved resonance and linewidth of an ultrafast switched GaAs/AlAs microcavity  

E-Print Network (OSTI)

We explore a planar GaAs/AlAs photonic microcavity using pump-probe spectroscopy. Free carriers are excited in the GaAs with short pump pulses. The time-resolved reflectivity is spectrally resolved short probe pulses. We show experimentally that the cavity resonance and its width depend on the dynamic refractive index of both the lambda-slab and the lambda/4 GaAs mirrors. We clearly observe a double exponential relaxation of both the the cavity resonance and its width, which is due to the different recombination timescales in the lambda-slab and the mirrors. In particular, the relaxation time due to the GaAs mirrors approaches the photon storage time of the cavity, a regime for which nonlinear effects have been predicted. The strongly non-single exponential behavior of the resonance and the width is in excellent agreement to a transfer-matrix model taking into account two recombination times. The change in width leads to a change in reflectivity modulation depth. The model predicts an optimal cavity Q for any...

Harding, Philip J; Hartsuiker, Alex; Nowicki-Bringuier, Yoanna-Reine; Gerard, Jean-Michel; Vos, Willem L

2009-01-01T23:59:59.000Z

193

Single-event dynamics of high-performance HBTs and GaAs MESFETs  

SciTech Connect

Picosecond charge-collection transients measured for GaAs/AlGaAs HBTs following 3.0 MeV [alpha]-particle and 620 nm picosecond laser excitation reveal charge-collection efficiencies up to twenty-eight times smaller than for GaAs MESFETs, with [approximately]90% of the charge collected within 75 ps of the ionizing event. The small charge-collection efficiency of the HBTs is a consequence of the ultrafast charge-collection dynamics in these devices. The authors show that picosecond laser excitation reproduces nicely the ion-induced transients, providing a valuable tool for the investigation of charge-collection and SEU phenomena in these devices.

McMorrow, D.; Melinger, J.S.; Campbell, A.B. (Naval Research Lab., Washington, DC (United States)); Weatherford, T.; Knudson, A.R.; Tran, L.H.

1993-12-01T23:59:59.000Z

194

Ultrafast optical pump-probe spectroscopy is used to reveal the coexistence of coupled antiferromagnetic (AFM)/ferroelectric (FE) and ferromagnetic (FM) orders in multiferroic TbMnO3 films, which can guide researchers in creating new kinds of multiferroic materials.  

Science Conference Proceedings (OSTI)

Multiferroic materials have attracted much interest in the past decade, due not only to their novel device applications, but also their manifestations of coupling and interactions between different order parameters (particularly electric polarization and magnetic order). Recently, much attention has been focused on perovskite manganites, RMnO{sub 3} (R = rare earth ions), due to the discovery of a large magnetoelectric effect in these materials. The first member of this family to be discovered was TbMnO{sub 3} (TMO), which is now well established as a typical magnetoelectric multiferroic. Extensive experimental and theoretical studies have already been done on single crystal TMO (SC-TMO). In brief, SC-TMO, with a distorted orthorhombic perovskite structure, has an antiferromagnetic (AFM) phase transition at T{sub N} {approx}40 K with sinusoidally ordered Mn moments. Below T{sub FE} {approx} 28 K, ferroelectric (FE) order develops owing to the appearance of cycloidal spiral spin structure. In contrast, there are relatively few reports describing the properties of TMO thin films (typically grown on SrTiO{sub 3} (STO) substrates). In general, thin films can enable new functionality in materials, as their physical parameters can be changed by modifying their structure via strain imposed by the substrate. Strain in particular has the potential to directly couple FE and FM orders, which is very rare. This could benefit electronic device applications by providing low power consumption, high speed operation, and greater electric/magnetic field controllability. Previous investigations of magnetic properties in TMO films revealed an unexpected ferromagnetic (FM) order, in contrast to SC-TMO. However, several important questions regarding these films are still unanswered for instance: (1) What mechanism induces FM order? (2) Can FM, sinusoidal AFM and spiral AFM (or FE) orders coexist? (3) Can FM order be coupled to FE order? To fully understand these unique materials, experimental techniques capable of dynamically unraveling the interplay between these degrees of freedom on an ultrafast timescale are needed. Here, we use ultrafast optical pump-probe spectroscopy to reveal coexisting coupled magnetic orders in epitaxial TMO thin films grown on (001)-STO, which were not observed in previous work. Our temperature (T)-dependent transient differential reflectivity ({Delta}R/R) measurements show clear signatures of sinusoidal AFM, spiral AFM (FE) and FM phases developing as the film thickness changes. We carry out first-principle density functional theory (DFT) calculations to explain the coupling between AFM/FE and FM orders. These results reveal that the coupling between different magnetic orders observed in our multiferroic TMO thin films may offer greater control of functionality as compared to bulk single crystal multiferroics.

Qi, Jingbo [Los Alamos National Laboratory; Zhu, Jianxin [Los Alamos National Laboratory; Trugman, Stuart A. [Los Alamos National Laboratory; Taylor, Antoinette [Los Alamos National Laboratory; Jia, Quanxi [Los Alamos National Laboratory; Prasankumar, Rohit [Los Alamos National Laboratory

2012-07-06T23:59:59.000Z

195

Dynamic tariffs  

SciTech Connect

The general theoretical models of dynamic tariffs, such as spot pricing, are extended in this paper to include the issues of optimal response of industrial consumers and the effect of large scale penetration of these tariffs on the utility load curve. If such tariffs are to serve their purpose consumers need to acquire the ability for flexible and dynamic response. While the hardware for this is readily available the theoretical models and software systems are not. These issues are examined and correlated with industrial site studies. A systematic analysis of the effect of significant consumer response on the system load curve is next undertaken. A methodologically sound approach to system load and price forecasting is presented.

David, A.K.; Lee, Y.C.

1989-08-01T23:59:59.000Z

196

Ultrafast neutron detector  

DOE Patents (OSTI)

A neutron detector of very high temporal resolution is described. It may be used to measure distributions of neutrons produced by fusion reactions that persist for times as short as about 50 picoseconds.

Wang, C.L.

1985-06-19T23:59:59.000Z

197

Ultrafast neutron detector  

DOE Patents (OSTI)

The invention comprises a neutron detector (50) of very high temporal resolution that is particularly well suited for measuring the fusion reaction neutrons produced by laser-driven inertial confinement fusion targets. The detector comprises a biased two-conductor traveling-wave transmission line (54, 56, 58, 68) having a uranium cathode (60) and a phosphor anode (62) as respective parts of the two conductors. A charge line and Auston switch assembly (70, 72, 74) launch an electric field pulse along the transmission line. Neutrons striking the uranium cathode at a location where the field pulse is passing, are enabled to strike the phosphor anode and produce light that is recorded on photographic film (64). The transmission line may be variously configured to achieve specific experimental goals.

Wang, Ching L. (Livermore, CA)

1987-01-01T23:59:59.000Z

198

Excited State Structural Dynamics of Carotenoids and ChargeTransfer Systems  

Science Conference Proceedings (OSTI)

This dissertation describes the development andimplementation of a visible/near infrared pump/mid-infrared probeapparatus. Chapter 1 describes the background and motivation ofinvestigating optically induced structural dynamics, paying specificattention to solvation and the excitation selection rules of highlysymmetric molecules such as carotenoids. Chapter 2 describes thedevelopment and construction of the experimental apparatus usedthroughout the remainder of this dissertation. Chapter 3 will discuss theinvestigation of DCM, a laser dye with a fluorescence signal resultingfrom a charge transfer state. By studying the dynamics of DCM and of itsmethyl deuterated isotopomer (an otherwise identical molecule), we areable to investigate the origins of the charge transfer state and provideevidence that it is of the controversial twisted intramolecular (TICT)type. Chapter 4 introduces the use of two-photon excitation to the S1state, combined with one-photon excitation to the S2 state of thecarotenoid beta-apo-8'-carotenal. These 2 investigations show evidencefor the formation of solitons, previously unobserved in molecular systemsand found only in conducting polymers Chapter 5 presents an investigationof the excited state dynamics of peridinin, the carotenoid responsiblefor the light harvesting of dinoflagellates. This investigation allowsfor a more detailed understanding of the importance of structuraldynamics of carotenoids in light harvesting.

Van Tassle, Aaron Justin

2006-09-01T23:59:59.000Z

199

Pulsed Power for a Dynamic Transmission Electron Microscope  

Science Conference Proceedings (OSTI)

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.

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

200

SciDAC Advances and Applications in Computational Beam Dynamics  

E-Print Network (OSTI)

codes have been used to model the SNS, LCLS, and ALS.Examples related to the LCLS injector and to the designan ultrafast streak camera for LCLS are shown in Figure 4.

2005-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "ultrafast solvation dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Reversibility, Water-Mediated Switching, and Directed Cell Dynamics  

E-Print Network (OSTI)

Reversible switching of the complex network dynamics of proteins is mimicked in selected network glasses and compacted small carbohydrate molecules. Protein transitions occur on long time scales ~ us -ms, evocative of the exponentially large viscosities found in glass-forming supercooled liquids just above the glass transition; in searching for mechanisms for reversibly slowed "geared activation", Kauzmann was led from proteins to glasses. I show here that selected network glasses and small carbohydrate molecules can be used to model such transitions, and elucidate in particular some universal aspects of tandem repeats. The human ankyrin tandem repeat D34, with a superhelical "coiled spring" structure which has 426 residues, folds reversibly and plastically. Such molecules are too large for present transition-state numerical simulations, currently limited to ~ 100 residues solvated by ~ 3000 water molecules for times ~ ns. The transition states of D34 exhibit a surprisingly simple collective ("geared") pattern when studied by fluorescence near its center, in samples modified mutageneously along its 12 helical repeats. One can understand this "plastic" pattern by taking advantage of a symmetric 45-atom carbohydrate molecular bridge to "cross over" from proteins to inorganic network glasses. There one easily identifies gears, and can show that the collective pattern is the signature of nonlocal, water-mediated [hydro(phobic/philic)] switching. Details of the transition patterns emerge from analyzing the amino acid alpha helical repeat sequences with water-only hydrophobicity scales. Freezing and melting of monolayer water films at physiological temperatures can enable ankyrin repeats to direct cell dynamics in muscles, membranes and cytoskeletons.

J. C. Phillips

2008-03-02T23:59:59.000Z

202

Systematic examination of dynamically driven organic reactions via kinetic isotope effects  

E-Print Network (OSTI)

Organic reactions are systematically examined experimentally and theoretically to determine the role dynamics plays in the outcome of the reaction. It is shown that trajectory studies are of vital importance in understanding reactions influenced by dynamical motion. This dissertation discusses how a combination of kinetic isotope effects, theoretical calculations, and quasiclassical dynamics trajectories aid in the understanding of the solvolysis of p-tolyldiazonium cation in water, the cycloadditions of cyclopentadiene with diphenylketene and dichloroketene, and the cycloaddition of 2- methyl-2-butene with dichloroketene. In the solvolysis of p-tolyldiazonium cation, significant 13C kinetic isotope effects are qualitatively consistent with a transition state leading to formation of an aryl cation, but on a quantitative basis, the isotope effects are not adequately accounted for by simple SN1 heterolysis to the aryl cation. The best predictions of the 13C isotope effects for the heterolytic process arise from transition structures solvated by clusters of water molecules. Dynamic trajectories starting from these transition structures afford products very slowly. The nucleophilic displacement process for aryldiazonium ions in water is determined to be at the boundary of the SN2Ar and SN1 mechanisms. The reaction of cyclopentadiene with diphenylketene affords both [4 + 2] and [2 + 2] cycloadducts directly. This is surprising. There is only one low-energy transition structure for adduct formation. Investigation of this reaction indicates that quasiclassical trajectories started from a single transition structure afford both [4 + 2] and [2 + 2] products. Overall, an understanding of the products, rates, selectivities, isotope effects, and mechanism in these reactions requires the explicit consideration of dynamic trajectories.

Ussing, Bryson Richard

2006-12-01T23:59:59.000Z

203

Excursions in Chemical Dynamics  

E-Print Network (OSTI)

2009). [118] F. A. Cotton, Chemical Applications of GroupExcursions in Chemical Dynamics by Shervin Fatehi AFall 2010 Excursions in Chemical Dynamics Copyright 2010 by

Fatehi, Shervin

2010-01-01T23:59:59.000Z

204

Evidence for ultra-fast outflows in radio-quiet AGNs: II - detailed photo-ionization modeling of Fe K-shell absorption lines  

E-Print Network (OSTI)

X-ray absorption line spectroscopy has recently shown evidence for previously unknown Ultra-fast Outflows (UFOs) in radio-quiet AGNs. In the previous paper of this series we defined UFOs as those absorbers with an outflow velocity higher than 10,000km/s and assessed the statistical significance of the associated blueshifted FeK absorption lines in a large sample of 42 local radio-quiet AGNs observed with XMM-Newton. In the present paper we report a detailed curve of growth analysis and directly model the FeK absorbers with the Xstar photo-ionization code. We confirm that the frequency of sources in the radio-quiet sample showing UFOs is >35%. The outflow velocity distribution spans from \\sim10,000km/s (\\sim0.03c) up to \\sim100,000km/s (\\sim0.3c), with a peak and mean value of \\sim42,000km/s (\\sim0.14c). The ionization parameter is very high and in the range log\\xi 3-6erg s^{-1} cm, with a mean value of log\\xi 4.2 erg s^{-1} cm. The associated column densities are also large, in the range N_H\\sim10^{22}-10^{24...

Tombesi, F; Reeves, J N; Palumbo, G G C; Braito, V; Dadina, M

2011-01-01T23:59:59.000Z

205

2012 ATOMIC AND MOLECULAR INTERACTIONS GORDON RESEARCH CONFERENCE AND GORDON RESEARCH SEMINAR, JULY 15-20, 2012  

SciTech Connect

At the 2012 Atomic and Molecular Interactions Gordon Conference, there will be talks in several broadly defined and partially overlapping areas: ? Intramolecular and single-collision reaction dynamics; ? Photophysics and photochemistry of excited states; ? Clusters, aerosols and solvation; ? Interactions at interfaces; ? Conformations and folding of large molecules; ? Interactions under extreme conditions of temperature and pressure. The theme of the Gordon Research Seminar on Atomic & Molecular Interactions, in keeping with the tradition of the Atomic and Molecular Interactions Gordon Research Conference, is far-reaching and involves fundamental research in the gas and condensed phases along with application of these ideas to practical chemical fields. The oral presentations, which will contain a combination of both experiment and theory, will focus on four broad categories: ? Ultrafast Phenomena; ? Excited States, Photoelectrons, and Photoions; ? Chemical Reaction Dynamics; ? Biomolecules and Clusters.

Zwier, Timothy

2012-07-20T23:59:59.000Z

206

Identification and Characterization of Defects in Functional Materials  

Science Conference Proceedings (OSTI)

Ultrafast Electron Diffraction Studies of Lattice Dynamics in Thin Bismuth Films · Ultrafine and Smooth Full Metal Nanostructures for Plasmonics · Understanding ...

207

Keith Gilmore  

Science Conference Proceedings (OSTI)

... Current research: Calculation of optical constants and dielectric response Ultrafast electron dynamics Spin-transfer torque. Previous publications: ...

2010-10-05T23:59:59.000Z

208

Computation of methodology-independent single-ion solvation properties from molecular simulations. IV. Optimized Lennard-Jones interaction parameter sets for the alkali and halide ions in water  

Science Conference Proceedings (OSTI)

The raw single-ion solvation free energies computed from atomistic (explicit-solvent) simulations are extremely sensitive to the boundary conditions and treatment of electrostatic interactions used during these simulations. However, as shown recently [M. A. Kastenholz and P. H. Huenenberger, J. Chem. Phys. 124, 224501 (2006); M. M. Reif and P. H. Huenenberger, J. Chem. Phys. 134, 144103 (2010)], the application of appropriate correction terms permits to obtain methodology-independent results. The corrected values are then exclusively characteristic of the underlying molecular model including in particular the ion-solvent van der Waals interaction parameters, determining the effective ion size and the magnitude of its dispersion interactions. In the present study, the comparison of calculated (corrected) hydration free energies with experimental data (along with the consideration of ionic polarizabilities) is used to calibrate new sets of ion-solvent van der Waals (Lennard-Jones) interaction parameters for the alkali (Li{sup +}, Na{sup +}, K{sup +}, Rb{sup +}, Cs{sup +}) and halide (F{sup -}, Cl{sup -}, Br{sup -}, I{sup -}) ions along with either the SPC or the SPC/E water models. The experimental dataset is defined by conventional single-ion hydration free energies [Tissandier et al., J. Phys. Chem. A 102, 7787 (1998); Fawcett, J. Phys. Chem. B 103, 11181] along with three plausible choices for the (experimentally elusive) value of the absolute (intrinsic) hydration free energy of the proton, namely, {Delta}G{sub hyd} {sup O-minus} [H{sup +}]=-1100, -1075 or -1050 kJ mol{sup -1}, resulting in three sets L, M, and H for the SPC water model and three sets L{sub E}, M{sub E}, and H{sub E} for the SPC/E water model (alternative sets can easily be interpolated to intermediate {Delta}G{sub hyd} {sup O-minus} [H{sup +}] values). The residual sensitivity of the calculated (corrected) hydration free energies on the volume-pressure boundary conditions and on the effective ionic radius entering into the calculation of the correction terms is also evaluated and found to be very limited. Ultimately, it is expected that comparison with other experimental ionic properties (e.g., derivative single-ion solvation properties, as well as data concerning ionic crystals, melts, solutions at finite concentrations, or nonaqueous solutions) will permit to validate one specific set and thus, the associated {Delta}G{sub hyd} {sup O-minus} [H{sup +}] value (atomistic consistency assumption). Preliminary results (first-peak positions in the ion-water radial distribution functions, partial molar volumes of ionic salts in water, and structural properties of ionic crystals) support a value of {Delta}G{sub hyd} {sup O-minus} [H{sup +}] close to -1100 kJ{center_dot}mol{sup -1}.

Reif, Maria M.; Huenenberger, Philippe H. [Laboratory of Physical Chemistry, ETH Zuerich, CH-8093 Zuerich (Switzerland)

2011-04-14T23:59:59.000Z

209

Drum-boiler dynamics  

Science Conference Proceedings (OSTI)

A nonlinear dynamic model for natural circulation drum-boilers is presented. The model describes the complicated dynamics of the drum, downcomer, and riser components. It is derived from first principles, and is characterized by a few physical parameters. ...

K. J. íStröM; R. D. Bell

2000-03-01T23:59:59.000Z

210

Dynamic Residential Window prototype  

NLE Websites -- All DOE Office Websites (Extended Search)

to have dynamic seasonal solar control: high solar gains in the winter with high insulation and low solar gains in the summer. Dynamic, high performance products can be based...

211

General Dynamics, Electric Boat  

Science Conference Proceedings (OSTI)

General Dynamics, Electric Boat. NVLAP Lab Code: 100560-0. Address and Contact Information: 75 Eastern Point Road ...

2013-08-16T23:59:59.000Z

212

NIST Photovoltaic carrier dynamics  

Science Conference Proceedings (OSTI)

... carrier dynamics in novel electronic photovoltaic materials being considered and developed for future solar cell and energy capture applications. ...

2013-04-01T23:59:59.000Z

213

How trehalose protects DNA in the dry state: a molecular dynamics simulation  

E-Print Network (OSTI)

Molecular dynamics simulations were conducted on a system consisting of a decamer DNA solvated by trehalose and water (molecular ratio= 1:2), to mimic a relatively dry state for the DNA molecule. Simulations were performed at two different temperatures, 300 K and 450 K. The B-form DNA structure was shown to be stable at both temperatures. The analysis of hydrogen bonds between trehalose/water and DNA revealed that trehalose and backbone DNA formed the largest number of hydrogen bonds and thus constituted the major effect of structural protection for DNA. The number of hydrogen bonds formed by each OH group of trehalose with the backbone DNA was compared. Different types of trehalose-DNA interactions were analyzed, with no prevalent pattern recognized. Diffusion constants for trehalose and water were also calculated, suggesting a glassy/viscose state of the simulation system. It is believed that trehalose protects DNA in the dry state through the network of hydrogen bonds built by the sugars, which reduces the structural fluctuations of DNA and prevents its denaturation.

Fu, Xuebing

2008-08-01T23:59:59.000Z

214

Mesoscale Structures at Complex Fluid-Fluid Interfaces: a Novel Lattice Boltzmann / Molecular Dynamics Coupling  

E-Print Network (OSTI)

Complex fluid-fluid interfaces featuring mesoscale structures with adsorbed particles are key components of newly designed materials which are continuously enriching the field of soft matter. Simulation tools which are able to cope with the different scales characterizing these systems are a fundamental requirement for efficient theoretical investigations. In this paper we present a novel simulation method, based on the approach of Ahlrichs and D\\"unweg [Ahlrichs and D\\"unweg, Int. J. Mod. Phys. C, 1998, 9, 1429], that couples the "Shan-Chen" multicomponent Lattice Boltzmann technique to off-lattice molecular dynamics. We demonstrate how this approach can be used to solve a wide class of challenging problems. Several examples are given, with an accent on bicontinuous phases formation in polyelectrolyte solutions and ferrofluid emulsions. We show also that the introduction of solvation free energies in the particle-fluid interaction unveils the hidden, multiscale nature of the particle-fluid coupling, allowing to treat symmetrically (and interchangeably) the on-lattice and off-lattice components of the system.

Marcello Sega; Mauro Sbragaglia; Sofia Sergeevna Kantorovich; Alexey Olegovich Ivanov

2013-06-04T23:59:59.000Z

215

Langevin molecular dynamics derived from Ehrenfest dynamics  

E-Print Network (OSTI)

Stochastic Langevin molecular dynamics for nuclei is derived from quantum classical molecular dynamics, also called Ehrenfest dynamics, at positive temperature, assuming that the molecular bulk system is in equilibrium and that the initial data for the electrons is stochastically perturbed from the ground state. The initial electron probability distribution is derived from the Liouville equilibrium solution generated by the nuclei acting as a heat bath for the electrons. The diffusion and friction coefficients in the Langevin equation satisfy Einstein's fluctuation-dissipation relation. The fluctuating initial data yields, in addition to the fluctuating diffusion terms, also a contribution to the drift, modifying the standard ab initio Born-Oppenheimer solution at zero temperature, where the electrons are in their ground state for the current nuclear configuration. The dissipative friction mechanism comes from the evolution of the electron ground state, due to slow dynamics of the nuclei, while the modified d...

Szepessy, Anders

2007-01-01T23:59:59.000Z

216

AVESTAR® - Dynamic Modeling  

NLE Websites -- All DOE Office Websites (Extended Search)

Dynamic Modeling Dynamic Modeling The AVESTAR team is pursuing research on the dynamic modeling and simulation of advanced energy systems ranging from power plants to power grids. Dynamic models provide a continuous view of energy systems in action by calculating their transient behavior over time. Plant-wide Models For power plants, dynamic models are used to analyze a wide variety of operating scenarios, including normal base load operation, startup, shutdown, feedstock switchovers, cycling, and load-following. Dynamic process and control models are also essential for analyzing plant responses to setpoint changes and disturbances, as well as malfunctions and abnormal situations. Other applications of plant-wide dynamic models include controllability and operational flexibility analyses, environmental studies, safety evaluations, and risk mitigation.

217

Influence of Domain Wall Pinning on the Dynamic Behavior of Magnetic  

NLE Websites -- All DOE Office Websites (Extended Search)

Influence of Domain Wall Pinning on the Dynamic Behavior of Magnetic Vortices Print Influence of Domain Wall Pinning on the Dynamic Behavior of Magnetic Vortices Print Soft magnetic, micron-sized thin-film structures with magnetic vortices are intriguing systems that may one day be used in ultrafast computer memories. In such systems, the otherwise in-plane magnetization turns perpendicular to the plane at the center of the vortex, forming the vortex core. Because such a core has two possible polarizations (up or down) and can be switched between these two states by a small alternating magnetic field, it could serve as a memory bit in future magnetic memory devices. However, these magnetic structures often contain numerous imperfections such as domain wall pinning sites, which have to be taken into account for the practical application of such systems. To study how these defects affect the dynamics of magnetic vortices, researchers from Belgium, Germany, and the United States investigated square-shaped and disk-shaped thin-film structures with artificially introduced imperfections in the form of nanometer-sized holes. They used time-resolved scanning transmission x-ray microscopy (STXM) at ALS Beamline 11.0.2 to determine the frequency at which these vortices vibrate (their eigenfrequency). The imperfections were found to cause a higher vibrational frequency in square-shaped structures, but did not influence the disk-shaped structures. Knowledge of the frequency is crucial for vortex-based memories, since the electric signal for writing data needs to be precisely tuned to it.

218

Influence of Domain Wall Pinning on the Dynamic Behavior of Magnetic  

NLE Websites -- All DOE Office Websites (Extended Search)

Influence of Domain Wall Pinning on the Dynamic Behavior of Magnetic Vortices Print Influence of Domain Wall Pinning on the Dynamic Behavior of Magnetic Vortices Print Soft magnetic, micron-sized thin-film structures with magnetic vortices are intriguing systems that may one day be used in ultrafast computer memories. In such systems, the otherwise in-plane magnetization turns perpendicular to the plane at the center of the vortex, forming the vortex core. Because such a core has two possible polarizations (up or down) and can be switched between these two states by a small alternating magnetic field, it could serve as a memory bit in future magnetic memory devices. However, these magnetic structures often contain numerous imperfections such as domain wall pinning sites, which have to be taken into account for the practical application of such systems. To study how these defects affect the dynamics of magnetic vortices, researchers from Belgium, Germany, and the United States investigated square-shaped and disk-shaped thin-film structures with artificially introduced imperfections in the form of nanometer-sized holes. They used time-resolved scanning transmission x-ray microscopy (STXM) at ALS Beamline 11.0.2 to determine the frequency at which these vortices vibrate (their eigenfrequency). The imperfections were found to cause a higher vibrational frequency in square-shaped structures, but did not influence the disk-shaped structures. Knowledge of the frequency is crucial for vortex-based memories, since the electric signal for writing data needs to be precisely tuned to it.

219

Influence of Domain Wall Pinning on the Dynamic Behavior of Magnetic  

NLE Websites -- All DOE Office Websites (Extended Search)

Influence of Domain Wall Pinning on the Dynamic Behavior of Magnetic Vortices Print Influence of Domain Wall Pinning on the Dynamic Behavior of Magnetic Vortices Print Soft magnetic, micron-sized thin-film structures with magnetic vortices are intriguing systems that may one day be used in ultrafast computer memories. In such systems, the otherwise in-plane magnetization turns perpendicular to the plane at the center of the vortex, forming the vortex core. Because such a core has two possible polarizations (up or down) and can be switched between these two states by a small alternating magnetic field, it could serve as a memory bit in future magnetic memory devices. However, these magnetic structures often contain numerous imperfections such as domain wall pinning sites, which have to be taken into account for the practical application of such systems. To study how these defects affect the dynamics of magnetic vortices, researchers from Belgium, Germany, and the United States investigated square-shaped and disk-shaped thin-film structures with artificially introduced imperfections in the form of nanometer-sized holes. They used time-resolved scanning transmission x-ray microscopy (STXM) at ALS Beamline 11.0.2 to determine the frequency at which these vortices vibrate (their eigenfrequency). The imperfections were found to cause a higher vibrational frequency in square-shaped structures, but did not influence the disk-shaped structures. Knowledge of the frequency is crucial for vortex-based memories, since the electric signal for writing data needs to be precisely tuned to it.

220

Influence of Domain Wall Pinning on the Dynamic Behavior of Magnetic  

NLE Websites -- All DOE Office Websites (Extended Search)

Influence of Domain Wall Pinning on the Dynamic Behavior of Magnetic Vortices Print Influence of Domain Wall Pinning on the Dynamic Behavior of Magnetic Vortices Print Soft magnetic, micron-sized thin-film structures with magnetic vortices are intriguing systems that may one day be used in ultrafast computer memories. In such systems, the otherwise in-plane magnetization turns perpendicular to the plane at the center of the vortex, forming the vortex core. Because such a core has two possible polarizations (up or down) and can be switched between these two states by a small alternating magnetic field, it could serve as a memory bit in future magnetic memory devices. However, these magnetic structures often contain numerous imperfections such as domain wall pinning sites, which have to be taken into account for the practical application of such systems. To study how these defects affect the dynamics of magnetic vortices, researchers from Belgium, Germany, and the United States investigated square-shaped and disk-shaped thin-film structures with artificially introduced imperfections in the form of nanometer-sized holes. They used time-resolved scanning transmission x-ray microscopy (STXM) at ALS Beamline 11.0.2 to determine the frequency at which these vortices vibrate (their eigenfrequency). The imperfections were found to cause a higher vibrational frequency in square-shaped structures, but did not influence the disk-shaped structures. Knowledge of the frequency is crucial for vortex-based memories, since the electric signal for writing data needs to be precisely tuned to it.

Note: This page contains sample records for the topic "ultrafast solvation dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Time-resolved infrared studies of the dynamics of ligand binding to cytochrome c oxidase  

DOE Green Energy (OSTI)

Time-resolved infrared spectroscopy (TRIRS) has been employed to study the reactions of small molecules with the cytochrome a{sub 3}-Cu{sub B} site of cytochrome c oxidase (CcO). All phases of these reactions have been investigated, from ultrafast phenomena (hundreds of femtoseconds) to relatively slow processes (milliseconds). The ligation dynamics immediately following photodissociation have been studied using a TRIR technique with time resolution of less than 1 ps. The rate of photoinitiated transfer of CO from Fe{sub a3}{sup 2+} to Cu{sub B}{sup +} was measured directly by monitoring the development of the transient Cu{sub B}{sup +}-CO absorption. The development of a stationary Cu{sub B}{sup +}-CO spectrum which is constant until the CO dissociates from Cu{sub B}{sup +} occurs in less than 1 ps, indicating that the photoinitiated transfer of CO is remarkably fast. This unprecedented ligand transfer rate has profound implications with regard to the structure and dynamics of the cytochrome a{sub 3}-Cu{sub B} site, the functional architecture of the protein and coordination dynamics in general. The photodissociation and recombination of Cn{sup {minus}} has also been studied using a real-time TRIR technique. The CN{sup {minus}} recombination rate of 430 s{sup {minus}1} is consistent with a recombination pathway similar to the one they have previously proposed for CO. The authors suggest the rate determining step for CN{sup {minus}} recombination is the thermal dissociation of the Fe{sub a3}{sup 2+}-L bond. 25 refs., 7 figs.

Dyer, R.B.; Peterson, K.A.; Stoutland, P.O.; Woodruff, W.H.

1991-01-01T23:59:59.000Z

222

Progresses in Ab Initio QM/MM Free Energy Simulations of Electrostatic Energies in Proteins: Accelerated QM/MM Studies of pKa, Redox Reactions and Solvation Free Energies  

Science Conference Proceedings (OSTI)

Hybrid quantum mechanical / molecular mechanical (QM/MM) approaches have been used to provide a general scheme for chemical reactions in proteins. However, such approaches still present a major challenge to computational chemists, not only because of the need for very large computer time in order to evaluate the QM energy but also because of the need for propercomputational sampling. This review focuses on the sampling issue in QM/MM evaluations of electrostatic energies in proteins. We chose this example since electrostatic energies play a major role in controlling the function of proteins and are key to the structure-function correlation of biological molecules. Thus, the correct treatment of electrostatics is essential for the accurate simulation of biological systems. Although we will be presenting here different types of QM/MM calculations of electrostatic energies (and related properties), our focus will be on pKa calculations. This reflects the fact that pKa of ionizable groups in proteins provide one of the most direct benchmarks for the accuracy of electrostatic models of macromolecules. While pKa calculations by semimacroscopic models have given reasonable results in many cases, existing attempts to perform pKa calculations using QM/MM-FEP have led to large discrepancies between calculated and experimental values. In this work, we accelerate our QM/MM calculations using an updated mean charge distribution and a classical reference potential. We examine both a surface residue (Asp3) of the bovine pancreatic trypsin inhibitor, as well as a residue buried in a hydrophobic pocket (Lys102) of the T4-lysozyme mutant. We demonstrate that by using this approach, we are able to reproduce the relevant sidechain pKas with an accuracy of 3 kcal/mol. This is well within the 7 kcal/mol energy difference observed in studies of enzymatic catalysis, and is thus sufficient accuracy to determine the main contributions to the catalytic energies of enzymes. We also provide an overall perspective of the potential of QM/MM calculations in general evaluations of electrostatic free energies, pointing out that our approach should provide a very powerful and accurate tool to predict the electrostatics of not only solution but also enzymatic reactions, as well as the solvation free energies of even larger systems, such as nucleic acid bases incorporated into DNA.

Kamerlin, Shina C. L.; Haranczyk, Maciej; Warshel, Arieh

2009-03-01T23:59:59.000Z

223

Chemical Structure and Dynamics  

NLE Websites -- All DOE Office Websites (Extended Search)

2154-3 2154-3 UC-400 Annual Report 2000 Chemical Structure and Dynamics Steven D. Colson, Associate Director Robin S. McDowell, Program Manager and the Staff of the Chemical Structure and Dynamics Program April 2001 Prepared for the U.S. Department of Energy under Contract DE-AC06-76RL01830 Chemical Structure and Dynamics 2000 Annual Report Contents Chemical Structure and Dynamics 2000 Annual Report Chemical Structure and Dynamics 2000 Annual Report 1. Introduction Chemical Structure and Dynamics Program......................................................... 1-3 2. Reaction Mechanisms at Liquid Interfaces Structure and Reactivity of Ice Surfaces and Interfaces G. A. Kimmel, Z. Dohnálek, K. P. Stevenson, R. S. Smith,

224

Influence of Domain Wall Pinning on the Dynamic Behavior of Magnetic...  

NLE Websites -- All DOE Office Websites (Extended Search)

us closer to the use of these ultrasmall structures in ultrafast computers. Top: Scanning Electron Microscope (SEM) images of a square- and a disk-shaped structure, with four...

225

Dynamic Instruction Fusion  

E-Print Network (OSTI)

SANTA CRUZ DYNAMIC INSTRUCTION FUSION A thesis submitted in4 2.2 Instruction Fusion & Complex10 3.1 Fusion Selection

Lee, Ian

2012-01-01T23:59:59.000Z

226

Fundamentals of Dynamic Behavior  

Science Conference Proceedings (OSTI)

Feb 28, 2011 ... Atomistically-Informed Dislocation Dynamics Simulations of High Rate Deformation of Single fcc Crystals: Zhiqiang Wang1; 1University of North ...

227

Dynamic Windows.pdf  

NLE Websites -- All DOE Office Websites (Extended Search)

including products with improved fixed or static properties and products with dynamic solar heat gain proper- ties. Nine representative window products are examined in eight...

228

Partial Dynamical Symmetry and Mixed Dynamics  

E-Print Network (OSTI)

Partial dynamical symmetry describes a situation in which some eigenstates have a symmetry which the quantum Hamiltonian does not share. This property is shown to have a classical analogue in which some tori in phase space are associated with a symmetry which the classical Hamiltonian does not share. A local analysis in the vicinity of these special tori reveals a neighbourhood of phase space foliated by tori. This clarifies the suppression of classical chaos associated with partial dynamical symmetry. The results are used to divide the states of a mixed system into ``chaotic'' and ``regular'' classes.

A. Leviatan; N. D. Whelan

1996-08-24T23:59:59.000Z

229

A High-Energy, Ultrashort-Pulse X-Ray System for the Dynamic Study of Heavy, Dense Materials  

Science Conference Proceedings (OSTI)

Thomson-scattering based x-ray radiation sources, in which a laser beam is scattered off a relativistic electron beam resulting in a high-energy x-ray beam, are currently being developed by several groups around the world to enable studies of dynamic material properties which require temporal resolution on the order of tens of femtoseconds to tens of picoseconds. These sources offer pulses that are shorter than available from synchrotrons, more tunable than available from so-called Ka sources, and more penetrating and more directly probing than ultrafast lasers. Furthermore, Thomson-scattering sources can scale directly up to x-ray energies in the few MeV range, providing peak brightnesses far exceeding any other sources in this regime. This dissertation presents the development effort of one such source at Lawrence Livermore National Laboratory, the Picosecond Laser-Electron InterAction for the Dynamic Evaluation of Structures (PLEIADES) project, designed to target energies from 30 keV to 200 keV, with a peak brightness on the order of 10{sup 18} photons {center_dot} s{sup -1} {center_dot} mm{sup -2} {center_dot} mrad{sup -2} {center_dot} 0.01% bandwidth{sup -1}. A 10 TW Ti:Sapphire based laser system provides the photons for the interaction, and a 100 MeV accelerator with a 1.6 cell S-Band photoinjector at the front end provides the electron beam. The details of both these systems are presented, as is the initial x-ray production and characterization, validating the theory of Thomson scattering. In addition to the systems used to enable PLEIADES, two alternative systems are discussed. An 8.5 GHz X-Band photoinjector, capable of sustaining higher accelerating gradients and producing lower emittance electron beams in a smaller space than the S-Band gun, is presented, and the initial operation and commissioning of this gun is presented. Also, a hybrid chirped-pulse amplification system is presented as an alternative to the standard regenerative amplifier technology in high-power ultrafast laser systems. This system combines an optical-parametric chirped-pulse amplification (OPCPA) system with a titanium:sapphire-based four-pass amplifier to provide the high pre-pulse contrast and ease of assembly of an OPCPA using a commercial pump laser while avoiding the loss of efficiency such a system would normally entail.

Gibson, D J

2004-09-17T23:59:59.000Z

230

Towards dynamic collaboration architectures  

Science Conference Proceedings (OSTI)

In this paper, we introduce the concept of dynamically changing between centralized, replicated, and hybrid collaboration architectures. It is implemented by providing users a function that dynamically changes the mapping between user-interface and program ... Keywords: ad-hoc collaboration, application sharing, collaboration architecture, latecomers, mobile collaboration

Goopeel Chung; Prasun Dewan

2004-11-01T23:59:59.000Z

231

Langevin molecular dynamics derived from Ehrenfest dynamics  

E-Print Network (OSTI)

Stochastic Langevin molecular dynamics for nuclei is derived from the Ehrenfest Hamiltonian system (also called quantum classical molecular dynamics) in a Kac-Zwanzig setting, with the initial data for the electrons stochastically perturbed from the ground state and the ratio, $M$, of nuclei and electron mass tending to infinity. The Ehrenfest nuclei dynamics is approximated by the Langevin dynamics with accuracy $o(M^{-1/2})$ on bounded time intervals and by $o(1)$ on unbounded time intervals, which makes the small $\\mathcal{O}(M^{-1/2})$ friction and $o(M^{-1/2})$ diffusion terms visible. The initial electron probability distribution is a Gibbs density at low temperture, derived by a stability and consistency argument: starting with any equilibrium measure of the Ehrenfest Hamiltonian system, the initial electron distribution is sampled from the equilibrium measure conditioned on the nuclei positions, which after long time leads to the nuclei positions in a Gibbs distribution (i.e. asymptotic stability); by consistency the original equilibrium measure is then a Gibbs measure.The diffusion and friction coefficients in the Langevin equation satisfy the Einstein's fluctuation-dissipation relation.

Anders Szepessy

2007-12-21T23:59:59.000Z

232

Solvation Effects in Self-Assembled Systems  

SciTech Connect

Many types of self-assembly can be found in nature. They include crystallization, the formation of micelles, and the folding of proteins. Recently there has been much interest in pursuing nano-to-microscopically engineered materials by way of self-assembly on imprinted or templated surfaces. In all of these diverse cases, wetting plays a critical role in the assembly process. Wetting involves the interactions of the substrate or amphiphilic molecule or macromolecule with a solvent. In many self-assembled systems we find that the critical feature of the system is a substrate! or macromolecule with a both hydrophilic and hydrophobic nature. In this paper we discuss the wetting properties of a striped surface where the stripes represent alternating chemical characteristics. We show how the chemical heterogeneity affects the wetting properties of the surface (e.g. the static contact angle), and discuss the length limitations on the soft lithography approach. In this paper, the wetting of a chemically heterogeneous surface is studied using a nonlocal Density Functional Theory (DFT). The results for the heterogeneous surface model we discuss have immediate implications for soft-lithography by self-assembly. It also lends fundamental insight into the mechanisms controlling self-assembly of macromolecules. We present the results of nonlocal 2D DFT calculations on the wetting properties of chemically heterogeneous surfaces. These calculations showed complex density distributions and phase behavior as a result of the heterogeneity. The location of the wetting transition are found to be strongly dependent on the extent and strength of the heterogeneity, and complete wetting was suppressed altogether if the hydrophobic parts of the surface were large enough. In these cases, the condensed nanophase may crystallize if the hydrophilic surface-fluid interactions are strong enough. By exploring the phase space including strength of hydrophilic interactions and extent of chemical heterogeneity, an operational phase diagram was established that could be used for designing nanoscopically tailored devices and materials.

Frink, L.J.D.

1998-11-10T23:59:59.000Z

233

Solar Dynamics | Open Energy Information  

Open Energy Info (EERE)

Dynamics Jump to: navigation, search Name Solar Dynamics Place Ottumwa, Iowa Zip IA 52501 Sector Solar Product Solar Dynamics is a US-based solar powered attic roof vents...

234

Dynamic Behavior of Materials V  

Science Conference Proceedings (OSTI)

Dynamic Characterization of Cast and Wrought Uranium-Niobium Metals · Dynamic Deformation Response of High-Strength Ni-Containing Steels.

235

LUSI :: LCLS Ultrafast Science Instruments  

NLE Websites -- All DOE Office Websites (Extended Search)

Go Home Project Pages LUSI Instruments Uniqueness of FEL X-rays X-ray FEL Science About LCLS Science with LCLS Calendar & Meetings Contact Us Office of ScienceU.S. DOE Current...

236

Modeling the Nanophase Structural Dynamics of Phenylated Sulfonated Poly Ether Ether Ketone Ketone (Ph-SPEEKK) Membranes as a Function of Hydration  

DOE Green Energy (OSTI)

Solvated phenylated sulfonated poly ether ether ketone ketone (Ph-SPEEKK) membranes in the presence of hydronium ions were modeled by classical molecular dynamics simulations. The characterization of the nanophase structure and dynamics of such membranes was carried out as a function of the water content lambda, where lambda is the number of water molecules per sulfonate group, for lambda values of 3.5, 6, 11, 25, and 40. Analysis of pair correlation functions supports the experimental observation of membrane swelling upon hydration as well the increase in water and hydronium ion diffusion with increasing lambda. While the average number of hydrogen bonds between hydronium ions and sulfonate groups is dramatically affected by the hydration level, the average lifetime of the hydrogen bonds remains essentially constant. The membrane is found to be relatively rigid and its overall flexibility shows little dependence on water content. Compared to Nafion, water and ion diffusion coefficients are considerably smaller at lower hydration levels and room temperature. However, at higher lambda values of 25 and 40 these coefficients are comparable to those in Nafion at a lambda value of 16. This study also shows that water diffusion in Ph-SPEEKK membranes at low hydration levels can be significantly improved by raising the temperature with important implications for proton conductivity.

Lins, Roberto D.; Devanathan, Ramaswami; Dupuis, Michel

2011-03-03T23:59:59.000Z

237

Cirrus Outflow Dynamics  

Science Conference Proceedings (OSTI)

Cirrus outflow from deep convection are analyzed as dynamically and thermodynamically active systems. The initial outflow is considered as an analog to wake collapse, in which a neutrally buoyant flow intrusion is flattened and stretched by its ...

Douglas K. Lilly

1988-05-01T23:59:59.000Z

238

WORKSHOP ON NUCLEAR DYNAMICS  

E-Print Network (OSTI)

Complete Events in Medium-Energy Nuclear Collisions" C-Y.+ corrections. (A) The nuclear potential-energy problem isquantum dynamics in high-energy nuclear collisions. We have

Myers, W.D.

2010-01-01T23:59:59.000Z

239

Optical dynamic circuit services  

Science Conference Proceedings (OSTI)

IP service, leased-line service and POTS service have been the three long-standing communication service offerings of providers. Recently, both commercial and research-andeducation network providers have started offering optical dynamic circuit services. ...

Malathi Veeraraghavan; Mark Karol; George Clapp

2010-11-01T23:59:59.000Z

240

A Molecular Dynamics Simulation  

Science Conference Proceedings (OSTI)

Ab Initio Local Energy and Local Stress Calculations: Applications to Materials ... Computational Fluid Dynamics and Experimental Results for the Horizontal .... Films and Applications to a New Generation of Multifunctional Devices/Systems.

Note: This page contains sample records for the topic "ultrafast solvation dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

A Molecular Dynamics  

Science Conference Proceedings (OSTI)

A Tale of Two States and More: Modeling of New Generation of Lattice Stability from Zero ... Analysis of Nano Fluid Using CFD-A Hybrid Approach for Cooling Purpose ... Molecular Dynamics Simulations of Grain Boundary Free Energy and

242

A Molecular Dynamic Study  

Science Conference Proceedings (OSTI)

A Tale of Two States and More: Modeling of New Generation of Lattice Stability from Zero ... Analysis of Nano Fluid Using CFD-A Hybrid Approach for Cooling Purpose ... Molecular Dynamics Simulations of Grain Boundary Free Energy and

243

Frontal Geostrophic Dynamics  

Science Conference Proceedings (OSTI)

From the primitive equations simplified dynamics are derived that apply to frontal situations in which interface slopes are important. The formalism, which eliminates inertial motions, is not Unlike the derivation of the quasi-geostrophic ...

Benoit Cushman-Roisin

1986-01-01T23:59:59.000Z

244

Dynamic manipulability of multifingered grasping  

Science Conference Proceedings (OSTI)

In this paper, we extend the concept of dynamic manipulability to evaluate the dynamic property of multifingered grasping systems consisting of amultifingered hand and a grasped object, and propose a measure of dynamic manipulability of multifingered ... Keywords: dynamic manipulability, grasping, internal force, multifingered hand, omnidirectionality

Yasuyoshi Yokokohji; Jose San Martin; Masaki Fujiwara

2009-08-01T23:59:59.000Z

245

The Dynamical Discrete Web  

E-Print Network (OSTI)

The dynamical discrete web (DDW), introduced in recent work of Howitt and Warren, is a system of coalescing simple symmetric one-dimensional random walks which evolve in an extra continuous dynamical parameter s. The evolution is by independent updating of the underlying Bernoulli variables indexed by discrete space-time that define the discrete web at any fixed s. In this paper, we study the existence of exceptional (random) values of s where the paths of the web do not behave like usual random walks and the Hausdorff dimension of the set of such exceptional s. Our results are motivated by those about exceptional times for dynamical percolation in high dimension by H\\"aggstrom, Peres and Steif, and in dimension two by Schramm and Steif. The exceptional behavior of the walks in DDW is rather different from the situation for dynamical random walks of Benjamini, H\\"aggstrom, Peres and Steif. In particular, we prove that there are exceptional values of s for which the walk from the origin S^s(n) has limsup S^s(n)/\\sqrt n \\leq K with a nontrivial dependence of the Hausdorff dimension on K. We also discuss how these and other results extend to the dynamical Brownian web, a natural scaling limit of DDW. The scaling limit is the focus of a paper in preparation; it was studied by Howitt and Warren and is related to the Brownian net of Sun and Swart.

L. R. G. Fontes; C. M. Newman; K. Ravishankar; E. Schertzer

2007-04-20T23:59:59.000Z

246

A First Principles Molecular Dynamics Study Of Calcium Ion In Water  

SciTech Connect

In this work we report on Car-Parrinello simulations of the divalent calcium ion in water, aimed at understanding the structure of the hydration shell and at comparing theoretical results with a series of recent experiments. Our paper shows some of the progress in the investigation of aqueous solutions brought about by the advent of ab initio molecular dynamics and highlights the importance of accessing subtle details of ion-water interactions from first-principles. Calcium plays a vital role in many biological systems, including signal transduction, blood clotting and cell division. In particular, calcium ions are known to interact strongly with proteins as they tend to bind well to both negatively charged (e.g. in aspartate and glutamate) and uncharged oxygens (e.g. in main-chain carbonyls). The ability of calcium to coordinate multiple ligands (from 6 to 8 oxygen atoms) with an asymmetric coordination shell enables it to cross-link different segments of a protein and induce large conformational changes. The great biochemical importance of the calcium ion has led to a number of studies to determine its hydration shell and its preferred coordination number in water. Experimental studies have used a variety of techniques, including XRD, EXAFS, and neutron diffraction to elucidate the coordination of Ca{sup 2+} in water. The range of coordination numbers (n{sub C}) inferred by X-ray diffraction studies varies from 6 to 8, and is consistent with that reported in EXAFS experiments (8 and 7.2). A wider range of values (6 to 10) was found in early neutron diffraction studies, depending on concentration, while a more recent measurement by Badyal, et al. reports a value close to 7. In addition to experimental measurements, many theoretical studies have been carried out to investigate the solvation of Ca{sup 2+} in water and have also reported a wide range of coordination numbers. Most of the classical molecular dynamics (MD) and QM/MM simulations report n{sub C} in the range of 8 to 10; in general, n{sub C} appears to be highly sensitive to the choice of the ion-water potential used in the calculations. Even ab initio MD simulations have so far obtained conflicting values for n{sub C}. For the structure of the first salvation shell Naor, et al. found n{sub C} = 7 to 8 and a Ca{sup 2+} - oxygen average distance (r{sub Ca-O}) of 2.64 {angstrom}, while Bako, et al. found n{sub C} = 6 and r{sub Ca-O} = 2.45 {angstrom}. In view of the existing controversies, we have carried out extensive Car-Parrinello simulations of Ca{sup 2+} solvation in water, using both a rigid and a flexible water model, up to time scales of 40 ps. Our simulations show variations of coordination numbers from 6, 7 and 8 occurring over intervals of {approx} 0.3/0.4 exchanges/ps, and yielding average coordination numbers of 6.2 and 7 for flexible and rigid water models, respectively. These results are consistent with those reported in recent EXAFS and neutron diffraction experiments. In addition, our calculations show an asymmetric coordination of Ca{sup 2+} to oxygen, similar to the case of Mg{sup 2+}.

Lightstone, F; Schwegler, E; Allesch, M; Gygi, F; Galli, G

2005-01-28T23:59:59.000Z

247

Surface Chemical Dynamics  

NLE Websites -- All DOE Office Websites (Extended Search)

Surface Chemical Dynamics Surface Chemical Dynamics The goal of the Surface Chemical Dynamics Program is to elucidate the underlying physical processes that determine the products (selectivity) and yield (efficiency) of chemical transformations relevant to energy-related chemistry on catalytic and nanostructured surfaces. Achieving this end requires understanding the evolution of the reactant-molecule/surface complex as molecules adsorb, bonds dissociate, surface species diffuse, new bonds form and products desorb. The pathways and time scales of these processes are ultimately determined by a multidimensional potential energy surface that is a function of the geometric and electronic structures of the surface and the reactant, product, intermediate and transition-state molecular and atomic species.

248

MAX Fluid Dynamics facility  

NLE Websites -- All DOE Office Websites (Extended Search)

MAX Fluid Dynamics facility MAX Fluid Dynamics facility Capabilities Engineering Experimentation Reactor Safety Testing and Analysis Overview Nuclear Reactor Severe Accident Experiments MAX NSTF SNAKE Aerosol Experiments System Components Laser Applications Robots Applications Other Facilities Other Capabilities Work with Argonne Contact us For Employees Site Map Help Join us on Facebook Follow us on Twitter NE on Flickr MAX Fluid Dynamics facility Providing high resolution data for development of computational tools that model fluid flow and heat transfer within complex systems such as the core of a nuclear reactor. 1 2 3 4 5 Hot and cold air jets are mixed within a glass tank while laser-based anemometers and a high-speed infrared camera characterize fluid flow and heat transfer behavior. Click on image to view larger size image.

249

Time-resolved THz studies of carrier dynamics in semiconductors, superconductors, and strongly-correlated electron materials  

Science Conference Proceedings (OSTI)

Perhaps the most important aspect of contemporary condensed matter physics involves understanding strong Coulomb interactions between the large number of electrons in a solid. Electronic correlations lead to the emergence of new system properties, such as metal-insulator transitions, superconductivity, magneto-resistance, Bose-Einstein condensation, the formation of excitonic gases, or the integer and fractional Quantum Hall effects. The discovery of high-Tc superconductivity in particular was a watershed event, leading to dramatic experimental and theoretical advances in the field of correlated-electron systems. Such materials often exhibit competition between the charge, lattice, spin, and orbital degrees of freedom, whose cause-effect relationships are difficult to ascertain. Experimental insight into the properties of solids is traditionally obtained by time-averaged probes, which measure e.g., linear optical spectra, electrical conduction properties, or the occupied band structure in thermal equilibrium. Many novel physical properties arise from excitations out of the ground state into energetically higher states by thermal, optical, or electrical means. This leads to fundamental interactions between the system's constituents, such as electron-phonon and electron-electron interactions, which occur on ultrafast timescales. While these interactions underlie the physical properties of solids, they are often only indirectly inferred from time-averaged measurements. Time-resolved spectroscopy, consequently, is playing an ever increasing role to provide insight into light-matter interaction, microscopic processes, or cause-effect relationships that determine the physics of complex materials. In the past, experiments using visible and near-infrared femtosecond pulses have been extensively employed, e.g. to follow relaxation and dephasing processes in metals and semiconductors. However, many basic excitations in strongly-correlated electron systems and nanoscale materials occur at lower energies. The terahertz (THz) regime is particularly rich in such fundamental resonances. This includes ubiquitous lattice vibrations and low-energy collective oscillations of conduction charges. In nanoscale materials, band structure quantization also yields novel infrared and THz transitions, including intersubband absorption in quantum wells. The formation of excitons in turn leads to low-energy excitations analogous to inter-level transitions in atoms. In transition-metal oxides, fundamental excitation gaps arise from charge pairing into superconducting condensates and other correlated states. This motivates the use of ultrafast THz spectroscopy as a powerful tool to study light-matter interactions and microscopic processes in nanoscale and correlated-electron materials.A distinct advantage of coherent THz pulses is that the amplitude and phase of the electric field can be measured directly, as the THz fields are coherent with the fs pulses from which they are generated. Using THz time-domain spectroscopy (THz-TDS), both the real and imaginary parts of the response functions (such as the dielectric function) are obtained directly without the need for Kramers?Kronig transforms. The THz response can also be expressed in terms of absorption and refractive index, or as the optical conductivity. The optical conductivity describes the current response of a many-body system to an electric field, an ideal tool to study conducting systems. A second important advantage is the ultrafast time resolution that results from the short temporal duration of the THz time-domain sources. In particular, optical-pump THz-probe spectroscopy enables a delicate probe of the transient THz conductivity after optical photoexcitation. These experiments can provide insight into quasiparticle interactions, phase transitions, or nonequilibrium dynamics. In this chapter we will provide many such examples. Since THz spectroscopy of solids is a quickly expanding field

Kaindl, Robert A.; Averitt, Richard D.

2006-11-14T23:59:59.000Z

250

Substructured multibody molecular dynamics.  

SciTech Connect

We have enhanced our parallel molecular dynamics (MD) simulation software LAMMPS (Large-scale Atomic/Molecular Massively Parallel Simulator, lammps.sandia.gov) to include many new features for accelerated simulation including articulated rigid body dynamics via coupling to the Rensselaer Polytechnic Institute code POEMS (Parallelizable Open-source Efficient Multibody Software). We use new features of the LAMMPS software package to investigate rhodopsin photoisomerization, and water model surface tension and capillary waves at the vapor-liquid interface. Finally, we motivate the recipes of MD for practitioners and researchers in numerical analysis and computational mechanics.

Grest, Gary Stephen; Stevens, Mark Jackson; Plimpton, Steven James; Woolf, Thomas B. (Johns Hopkins University, Baltimore, MD); Lehoucq, Richard B.; Crozier, Paul Stewart; Ismail, Ahmed E.; Mukherjee, Rudranarayan M. (Rensselaer Polytechnic Institute, Troy, NY); Draganescu, Andrei I.

2006-11-01T23:59:59.000Z

251

Introduction to Accelerated Molecular Dynamics  

SciTech Connect

Molecular Dynamics is the numerical solution of the equations of motion of a set of atoms, given an interatomic potential V and some boundary and initial conditions. Molecular Dynamics is the largest scale model that gives unbiased dynamics [x(t),p(t)] in full atomistic detail. Molecular Dynamics: is simple; is 'exact' for classical dynamics (with respect to a given V); can be used to compute any (atomistic) thermodynamical or dynamical properties; naturally handles complexity -- the system does the right thing at the right time. The physics derives only from the interatomic potential.

Perez, Danny [Los Alamos National Laboratory

2012-07-10T23:59:59.000Z

252

Introduction to Accelerated Molecular Dynamics  

SciTech Connect

Molecular Dynamics is the numerical solution of the equations of motion of a set of atoms, given an interatomic potential V and some boundary and initial conditions. Molecular Dynamics is the largest scale model that gives unbiased dynamics [x(t),p(t)] in full atomistic detail. Molecular Dynamics: is simple; is 'exact' for classical dynamics (with respect to a given V); can be used to compute any (atomistic) thermodynamical or dynamical properties; naturally handles complexity -- the system does the right thing at the right time. The physics derives only from the interatomic potential.

Perez, Danny [Los Alamos National Laboratory

2012-07-10T23:59:59.000Z

253

An Ocean Dynamical Thermostat  

Science Conference Proceedings (OSTI)

The role of ocean dynamics in the regulation of tropical sea surface temperatures (SSTs) is investigated using the Zebiak-Cane coupled occan-atmosphere model. The model is forced with a uniform heating, or cooling, varying between ±40 W m?2 into ...

Amy C. Clement; Richard Seager; Mark A. Cane; Stephen E. Zebiak

1996-09-01T23:59:59.000Z

254

Neutron Scattering and Dynamics  

Science Conference Proceedings (OSTI)

... "Molecule" H2O (N2)0.8(O2)0.2 Al Cd sigma_s barn 168.3 20.1 1.5 6.5 ... 31 Collective dynamics Animation courtesy of A. Zheludev (ORNL) ...

2009-09-15T23:59:59.000Z

255

Tropical Cyclone Eye Dynamics  

Science Conference Proceedings (OSTI)

A new perspective of the dynamics of a tropical cyclone eye is given in which eye subsidence and the adiabatic warming accompanying it are accounted for directly from the equations of motion. Subsidence is driven by an adverse, axial gradient of ...

R. K. Smith

1980-06-01T23:59:59.000Z

256

Bütschli dynamic droplet system  

Science Conference Proceedings (OSTI)

Dynamical oil-water systems such as droplets display lifelike properties and may lend themselves to chemical programming to perform useful work, specifically with respect to the built environment. We present Bütschli water-in-oil droplets as a model ... Keywords: Otto Bütschli, architecture, droplet, living technology, olive oil, origins of life

Rachel Armstrong; Martin Hanczyc

2013-10-01T23:59:59.000Z

257

BLOWER SYSTEM DYNAMICS  

SciTech Connect

An analysis is presented of the dynamics of a turboblower acting together with its connecting circuit. This is to be distinguished from the aero- thermodynamics involved in the design of the blower itself. The effect on system stability of blower and circuit characteristics is discussed. (auth)

Furgerson, W.T.

1958-04-16T23:59:59.000Z

258

Entanglement dynamics during decoherence  

Science Conference Proceedings (OSTI)

The evolution of the entanglement between oscillators that interact with the same environment displays highly non-trivial behavior in the long time regime. When the oscillators only interact through the environment, three dynamical phases were identified ... Keywords: 03.65.Yz, 03.67.Bg, 03.67.Mn, 05.40.Jc, Decoherence, Entanglement, Quantum Brownian Motion

Juan Pablo Paz; Augusto J. Roncaglia

2009-12-01T23:59:59.000Z

259

Probing the hydration structure of polarizable halides: a multi-edge XAFS and molecular dynamics study of the iodide anion.  

DOE Green Energy (OSTI)

A comprehensive analysis of the H2O structure about aqueous iodide (I-) is reported from molecular dynamics (MD) simulation and x-ray absorption fine structure (XAFS) measurements. XAFS spectra from the iodide K-, L1-, and L3- edges were co-refined to establish the complete structure of the first hydration shell about aqueous I-. The results show approximately 6.3 water molecules located at I-H and I-O distances of 2.65 Å and 3.50 Å, respectively. Whereas the I-O bond is moderately disordered (Debye Waller factor, ?2 = 0.017 Å2) due to the relatively low charge-to-ion radius ratio, the I-H interaction shows even higher disorder (?2 = 0.036 Å2) due to the variable angular orientation of water at the ion surface. Molecular dynamics simulations employing both DFT (+dispersion) and classical potentials generate quite similar structures and they both agree to a large extent with the structure from the experimental XAFS. However the DFT-MD simulations provide a description of molecular structure that is more consistent with the XAFS experiment data. We employ a molecular anaylsis in which we incrementally evaluate the structural contributions from each of the nearest-neighbor water molecules about the iodide to provide a clear picture of the hydrated structure. For the DFT description of molecular interaction, a water molecule in the first shell has more freedom to rotate about the O atom when compared to motions resulting from a classical potential. Further, the hydrogen bonding of first-shell water with the second shell water establishes an strong ordering of the water about I- surface leading to characteristic O-I-O angles of 79 and 142°. This ordering, in addition to the higher coordination number leads to a more symmetric solvation from the DFT-MD configurations relative to the classical potential simulation.

Fulton, John L.; Schenter, Gregory K.; Baer, Marcel; Mundy, Christopher J.; Dang, Liem X.; Balasubramanian, Mahalingam

2010-10-14T23:59:59.000Z

260

Cloud computing for dynamic systems  

Science Conference Proceedings (OSTI)

Cloud computing is a fast emerging model for enabling dynamic on-demand computing and IT-based services. It promotes dynamic properties and characteristics such as scalability, agility, flexibility, virtualised and distributed on-demand computing. However, ...

Khaled Sabry

2011-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "ultrafast solvation dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Dynamic Scaling of Manipulator Trajectories  

E-Print Network (OSTI)

A fundamental time-scaling property of manipulator dynamics has been identified that allows modification of movement speed without complete dynamics recalculation. By exploiting this property, it can be determined ...

Hollerbach, John M.

1983-01-01T23:59:59.000Z

262

NETL: Energy System Dynamics Focus Area  

NLE Websites -- All DOE Office Websites (Extended Search)

Energy System Dynamics Onsite Research Energy System Dynamics Energy System Dynamics (ESD) is a focus area of the National Energy Technology Laboratory's Office of Research and...

263

Shared and Dynamic Libraries on Edison  

NLE Websites -- All DOE Office Websites (Extended Search)

Shared and Dynamic Libraries Shared and Dynamic Libraries The Edison system can support applications that use dynamic shared libraries (DSL) on the compute nodes. Some...

264

Dynamic Worldwide Solar Energy | Open Energy Information  

Open Energy Info (EERE)

Dynamic Worldwide Solar Energy Jump to: navigation, search Name Dynamic Worldwide Solar Energy Sector Solar Product US-based solar developer and financer. References Dynamic...

265

Cell Dynamics and Process Control  

Science Conference Proceedings (OSTI)

ALUMINIUM REDUCTION TECHNOLOGY VII: Cell Dynamics And Process ... WITH RELEVANS TO POINT FEEDING ALUMINIUM CELL: Ove Kobbeltvedt, ...

266

Dynamic Behavior of Materials VI  

Science Conference Proceedings (OSTI)

Capturing Microstructural Features Related to Dynamic Damage Nucleation ... Structural Alumina during Low Velocity Impact Used in Protective Systems.

267

Interaction between economic dynamical systems  

Science Conference Proceedings (OSTI)

The paper considers economic dynamical systems, the state spaces being the Riemannian manifolds. Between two economic dynamical systems, global feedforward and the feedback interaction is defined and the connection between their linearization and prolongation ... Keywords: economic dynamical system, economic flow, feedback, feedforward, linearization, prolongation by derivation

Constantin Patrascoiu

2009-07-01T23:59:59.000Z

268

Accelerated Molecular Dynamics Methods  

NLE Websites -- All DOE Office Websites (Extended Search)

Dynamics Methods Dynamics Methods for Infrequent Events Arthur F. Voter Theoretical Division Los Alamos National Laboratory Los Alamos, New Mexico U.S. Department of Energy Theory Focus Session on Hydrogen Storage Materials Crystal City, VA May 18, 2006 Los Alamos Acknowledgments Blas P. Uberuaga (LANL, MST-8) Francesco Montalenti (U. Milano-Bicocca) Graeme Henkelman (U. Texas at Austin) Timothy C. Germann (LANL, X-7) James A. Sprague (NRL) Mads Sorensen (Novo Nordisk A/S, Copenhagen) Sriram Swaminarayan (LANL, MST-8) Steve Stuart (Clemson) David Sholl (Carnegie Mellon) John Hamilton (Sandia) Wolfgang Windl (Ohio State) Roger Smith (U. Loughborough) Robin Grimes (Imperial College) Kurt Sickafus (LANL, MST-8) Jacques Amar (U. Toledo) DOE Office of Basic Energy Sciences Motorola Intel Los Alamos Outline

269

Critical dynamics and decoherence  

SciTech Connect

We study dynamics of decoherence in a generic model where the environment is driven and undergoes a quantum phase transition. We model the environment by the Ising chain in the transverse field, and assume that the decohering system is a central spin-1/2. We found that when the environment is quenched slowly through the critical point, the decoherence factor of the central spin undergoes rapid decay that encodes the critical exponents of the environment. We also found that decoherence in a non-equilibrated, kink-contaminated, environment can be stronger than in a vacuum one. We derived a remarkably simple analytical expression that describes post-transition decoherence and predicts periodicities involving all system parameters. This research connects the fields of decoherence, quantum phase transitions, and Kibble-Zurek non-equilibrium dynamics.

Damski, Bogdan [Los Alamos National Laboratory; Quan, Haitao T [Los Alamos National Laboratory; Zurek, Wojciech H [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

270

Social Dynamics of Science  

E-Print Network (OSTI)

The birth and decline of disciplines are critical to science and society. However, no quantitative model to date allows us to validate competing theories of whether the emergence of scientific disciplines drives or follows the formation of social communities of scholars. Here we propose an agent-based model based on a \\emph{social dynamics of science,} in which the evolution of disciplines is guided mainly by the social interactions among scientists. We find that such a social theory can account for a number of stylized facts about the relationships between disciplines, authors, and publications. These results provide strong quantitative support for the key role of social interactions in shaping the dynamics of science. A "science of science" must gauge the role of exogenous events, such as scientific discoveries and technological advances, against this purely social baseline.

Sun, Xiaoling; Milojevi?, Staša; Flammini, Alessandro; Menczer, Filippo

2013-01-01T23:59:59.000Z

271

Dynamic radioactive particle source  

SciTech Connect

A method and apparatus for providing a timed, synchronized dynamic alpha or beta particle source for testing the response of continuous air monitors (CAMs) for airborne alpha or beta emitters is provided. The method includes providing a radioactive source; placing the radioactive source inside the detection volume of a CAM; and introducing an alpha or beta-emitting isotope while the CAM is in a normal functioning mode.

Moore, Murray E.; Gauss, Adam Benjamin; Justus, Alan Lawrence

2012-06-26T23:59:59.000Z

272

KHALIL AMINE, PH  

NLE Websites -- All DOE Office Websites (Extended Search)

Reactive and Solvation Dynamics and their Critical Tests at American Chemical Society (ACS) 195th National Meeting, Boston (1990) Graduate Student Teaching Award (1987, 1989)...

273

Meeting Residential Ventilation Standards Through Dynamic Control...  

NLE Websites -- All DOE Office Websites (Extended Search)

Meeting Residential Ventilation Standards Through Dynamic Control of Ventilation Systems Title Meeting Residential Ventilation Standards Through Dynamic Control of Ventilation...

274

Atomistic Time-Domain Simulations of Light-Harvesting and Charge-Transfer Dynamics in Novel Nanoscale Materials for Solar Hydrogen Production.  

Science Conference Proceedings (OSTI)

Funded by the DOE grant (i) we continued to study and analyze the atomistic detail of the electron transfer (ET) across the chromophore-TiO2 interface in Gratzel cell systems for solar hydrogen production. (ii) We extensively investigated the nature of photoexcited states and excited state dynamics in semiconductor quantum dots (QD) designed for photovoltaic applications. (iii) We continued a newly initiated research direction focusing on excited state properties and electron-phonon interactions in nanoscale carbon materials. Over the past year, the results of the DOE funded research were summarized in 3 review articles. 12 original manuscripts were written. The research results were reported in 28 invited talks at conferences and university seminars. 20 invitations were accepted for talks in the near future. 2 symposia at national and international meetings have being organized this year on topics closely related to the DOE funded project, and 2 more symposia have been planned for the near future. We summarized the insights into photoinduced dynamics of semiconductor QDs, obtained from our time-domain ab initio studies. QDs exhibit both molecular and bulk properties. Unlike either bulk or molecular materials, QD properties can be modified continuously by changing QD shape and size. However, the chemical and physical properties of molecular and bulk materials often contradict each other, which can lead to differing viewpoints about the behavior of QDs. For example, the molecular view suggests strong electron-hole and charge-phonon interactions, as well as slow energy relaxation due to mismatch between electronic energy gaps and phonon frequencies. In contrast, the bulk view advocates that the kinetic energy of quantum confinement is greater than electron-hole interactions, that charge-phonon coupling is weak, and that the relaxation through quasi-continuous bands is rapid. By synthesizing the bulk and molecular viewpoints, we clarified the controversies and provided a unified atomistic picture of the nature and dynamics of photoexcited states in semiconductor QDs. We also summarized our recent findings about the photoinduced electron dynamics at the chromophore-semiconductor interfaces from a time-domain ab initio perspective. The interface provides the foundation for a new, promising type of solar cell and presents a fundamentally important case study for several fields, including photo-, electro- and analytical chemistries, molecular electronics, and photography. Further, the interface offers a classic example of an interaction between an organic molecular species and an inorganic bulk material. Scientists employ different concepts and terminologies to describe molecular and solid states of matter, and these differences make it difficult to describe the interface with a single model. At the basic atomistic level of description, however, this challenge can be largely overcome. Recent advances in non-adiabatic molecular dynamics and time-domain density functional theory have created a unique opportunity for simulating the ultrafast, photoinduced processes on a computer very similar to the way that they occur in nature. These state-of-the-art theoretical tools offered a comprehensive picture of a variety of electron transfer processes that occur at the interface, including electron injection from the chromophore to the semiconductor, electron relaxation and delocalization inside the semiconductor, back-transfer of the electron to the chromophore and to the electrolyte, and regeneration of the neutral chromophore by the electrolyte. The ab initio time-domain modeling is particularly valuable for understanding these dynamic features of the ultrafast electron transfer processes, which cannot be represented by a simple rate description. We demonstrated using symmetry adapted cluster theory with configuration interaction (SAC-CI) that charging of small PbSe nanocrystals (NCs) greatly modifies their electronic states and optical excitations. Conduction and valence band transitions that are not available in neutral NCs dominate

Prezhdo, Oleg V.

2012-03-22T23:59:59.000Z

275

Atomistic Time-Domain Simulations of Light-Harvesting and Charge-Transfer Dynamics in Novel Nanoscale Materials for Solar Hydrogen Production.  

DOE Green Energy (OSTI)

Funded by the DOE grant (i) we continued to study and analyze the atomistic detail of the electron transfer (ET) across the chromophore-TiO2 interface in Gratzel cell systems for solar hydrogen production. (ii) We extensively investigated the nature of photoexcited states and excited state dynamics in semiconductor quantum dots (QD) designed for photovoltaic applications. (iii) We continued a newly initiated research direction focusing on excited state properties and electron-phonon interactions in nanoscale carbon materials. Over the past year, the results of the DOE funded research were summarized in 3 review articles. 12 original manuscripts were written. The research results were reported in 28 invited talks at conferences and university seminars. 20 invitations were accepted for talks in the near future. 2 symposia at national and international meetings have being organized this year on topics closely related to the DOE funded project, and 2 more symposia have been planned for the near future. We summarized the insights into photoinduced dynamics of semiconductor QDs, obtained from our time-domain ab initio studies. QDs exhibit both molecular and bulk properties. Unlike either bulk or molecular materials, QD properties can be modified continuously by changing QD shape and size. However, the chemical and physical properties of molecular and bulk materials often contradict each other, which can lead to differing viewpoints about the behavior of QDs. For example, the molecular view suggests strong electron-hole and charge-phonon interactions, as well as slow energy relaxation due to mismatch between electronic energy gaps and phonon frequencies. In contrast, the bulk view advocates that the kinetic energy of quantum confinement is greater than electron-hole interactions, that charge-phonon coupling is weak, and that the relaxation through quasi-continuous bands is rapid. By synthesizing the bulk and molecular viewpoints, we clarified the controversies and provided a unified atomistic picture of the nature and dynamics of photoexcited states in semiconductor QDs. We also summarized our recent findings about the photoinduced electron dynamics at the chromophore-semiconductor interfaces from a time-domain ab initio perspective. The interface provides the foundation for a new, promising type of solar cell and presents a fundamentally important case study for several fields, including photo-, electro- and analytical chemistries, molecular electronics, and photography. Further, the interface offers a classic example of an interaction between an organic molecular species and an inorganic bulk material. Scientists employ different concepts and terminologies to describe molecular and solid states of matter, and these differences make it difficult to describe the interface with a single model. At the basic atomistic level of description, however, this challenge can be largely overcome. Recent advances in non-adiabatic molecular dynamics and time-domain density functional theory have created a unique opportunity for simulating the ultrafast, photoinduced processes on a computer very similar to the way that they occur in nature. These state-of-the-art theoretical tools offered a comprehensive picture of a variety of electron transfer processes that occur at the interface, including electron injection from the chromophore to the semiconductor, electron relaxation and delocalization inside the semiconductor, back-transfer of the electron to the chromophore and to the electrolyte, and regeneration of the neutral chromophore by the electrolyte. The ab initio time-domain modeling is particularly valuable for understanding these dynamic features of the ultrafast electron transfer processes, which cannot be represented by a simple rate description. We demonstrated using symmetry adapted cluster theory with configuration interaction (SAC-CI) that charging of small PbSe nanocrystals (NCs) greatly modifies their electronic states and optical excitations. Conduction and valence band transitions that are not available in neutral NCs dominate

Prezhdo, Oleg V.

2012-03-22T23:59:59.000Z

276

Definition: Dynamic Interchange Schedule Or Dynamic Schedule | Open Energy  

Open Energy Info (EERE)

Schedule Or Dynamic Schedule Schedule Or Dynamic Schedule Jump to: navigation, search Dictionary.png Dynamic Interchange Schedule Or Dynamic Schedule A telemetered reading or value that is updated in real time and used as a schedule in the AGC/ACE equation and the integrated value of which is treated as a schedule for interchange accounting purposes. Commonly used for scheduling jointly owned generation to or from another Balancing Authority Area.[1] Related Terms balancing authority, balancing authority area, smart grid References ↑ Glossary of Terms Used in Reliability Standards An in LikeLike UnlikeLike You like this.Sign Up to see what your friends like. line Glossary Definition Retrieved from "http://en.openei.org/w/index.php?title=Definition:Dynamic_Interchange_Schedule_Or_Dynamic_Schedule&oldid=502492

277

Heat transfer dynamics  

Science Conference Proceedings (OSTI)

As heat transfer technology increases in complexity, it becomes more difficult for those without thermal dynamics engineering training to choose between competitive heat transfer systems offered to meet their drying requirements. A step back to the basics of heat transfer can help professional managers and papermakers make informed decisions on alternative equipment and methods. The primary forms of heat and mass transfer are reviewed with emphasis on the basics, so a practical understanding of each is gained. Finally, the principles and benefits of generating infrared energy by combusting a gaseous hydrocarbon fuel are explained.

Smith, T.M. (Marsden, Inc., Pennsauken, NJ (United States))

1994-08-01T23:59:59.000Z

278

Dynamic Chirality in Nuclei  

SciTech Connect

The possible chiral interpretation of twin bands in odd-odd nuclei was investigated in the Interacting Boson Fermion-Fermion Model. The analysis of the wave functions has shown that the possibility for angular momenta of the valence proton, neutron and core to find themselves in the favorable, almost orthogonal geometry is present, but not dominant. Such behaviour is found to be similar in nuclei where both the level energies and the electromagnetic decay properties display the chiral pattern, as well as in those where only the energies of the corresponding levels in the twin bands are close together. The difference in the structure of the two types of chiral candidates nuclei can be attributed to different beta and gamma fluctuations, induced by the exchange boson-fermion interaction of the Interacting Boson Fermion-Fermion Model. In both cases the chirality is weak and dynamic. The existence of doublets of bands in {sup 134}Pr can be attributed to dynamic chirality dominated by shape fluctuations.

Tonev, D. [Institute for Nuclear Research and Nuclear Energy, BAS, 1784 Sofia (Bulgaria); INFN, Laboratori Nazionali di Legnaro, 35020 Legnaro (Italy); Angelis, G. de [INFN, Laboratori Nazionali di Legnaro, 35020 Legnaro (Italy); Brant, S. [Department of Physics, Faculty of Science, University of Zagreb, 10000 Zagreb (Croatia); Petkov, P. [Institute for Nuclear Research and Nuclear Energy, BAS, 1784 Sofia (Bulgaria); Ventura, A. [ENEA, 40129 Bologna and INFN, Sezione di Bologna (Italy)

2009-08-26T23:59:59.000Z

279

Gas-Phase Molecular Dynamics  

NLE Websites -- All DOE Office Websites (Extended Search)

Gas-Phase Molecular Dynamics Gas-Phase Molecular Dynamics The Gas-Phase Molecular Dynamics Group is dedicated to developing and applying spectroscopic and theoretical tools to challenging problems in chemical physics related to reactivity, structure, dynamics and kinetics of transient species. Recent theoretical work has included advances in exact variational solution of vibrational quantum dynamics, suitable for up to five atoms in systems where large amplitude motion or multiple strongly coupled modes make simpler approximations inadequate. Other theoretical work, illustrated below, applied direct dynamics, quantum force trajectory calculations to investigate a series of reactions of the HOCO radical. The potential energy surface for the OH + CO/ H + CO2 reaction, showing two barriers (TS1 and TS2) and the deep HOCO well along the minimum energy pathway. The inset figure shows the experimental and calculated reactivity of HOCO with selected collision partners. See J.S. Francisco, J.T. Muckerman and H.-G. Yu, "HOCO radical chemistry,"

280

Prokaryotic Gene Finding Based on Physicochemical Characteristics of Codons Calculated from Molecular Dynamics Simulations  

E-Print Network (OSTI)

calculated solvation energies and flexibility of codon sequences as well as codon usage in genes and amino are typically very small in prokaryotic genomes. Usage of a genome-specific plane as opposed to a common energy, the base pair stacking energy, and an index of the propensity of a codon for protein-nucleic acid

Jayaram, Bhyravabotla

Note: This page contains sample records for the topic "ultrafast solvation dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
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281

Particle Dynamics And Emergent Gravity  

E-Print Network (OSTI)

The emergent gravity proposal is examined within the framework of noncommutative QED/gravity correspondence from particle dynamics point of view.

Amir H. Fatollahi

2008-05-08T23:59:59.000Z

282

Nuclear Matter and Nuclear Dynamics  

E-Print Network (OSTI)

Highlights on the recent research activity, carried out by the Italian Community involved in the "Nuclear Matter and Nuclear Dynamics" field, will be presented.

M Colonna

2009-02-26T23:59:59.000Z

283

Beamline 6.0.1  

NLE Websites -- All DOE Office Websites (Extended Search)

1 Print Ultrafast Femtosecond Dynamics Hard X Ray GENERAL BEAMLINE INFORMATION Operational Yes Proposal cycle Proposals for General Sciences Beamlines (6-month cycle) Source...

284

4D Functional Materials Science with X-ray Microscopy  

Science Conference Proceedings (OSTI)

Ultrafast Electron Diffraction Studies of Lattice Dynamics in Thin Bismuth Films · Understanding Fatigue and Corrosion-Fatigue Behavior by In Situ 3D X-ray ...

285

Beamline 6.0.1  

NLE Websites -- All DOE Office Websites (Extended Search)

0.1 Print Ultrafast Femtosecond Dynamics Hard X Ray GENERAL BEAMLINE INFORMATION Operational Yes Proposal cycle Proposals for General Sciences Beamlines (6-month cycle) Source...

286

Ligand Rearrangement Reactions of Cr(CO)6 in Alcohol Solutions:Experiment and Theory  

SciTech Connect

The ligand rearrangement reaction of Cr(CO)6 is studied in a series of alcohol solutions using ultrafast, infrared spectroscopy and Brownian dynamics simulations.

Shanoski, Jennifer E.; Glascoe, Elizabeth A.; Harris, Charles B.

2005-09-24T23:59:59.000Z

287

Chemical Sciences Division: Introduction: Organization Chart  

NLE Websites -- All DOE Office Websites (Extended Search)

Chart Ultrafast X-Ray Science Laboratory ALS-MES Beamline Actinde Science Chemical Dynamics Beamline Centers Programs Chemical Physics The Glenn T. Seaborg Center...

288

CFN | Video Library  

NLE Websites -- All DOE Office Websites (Extended Search)

for Academia and High Tech Industry. 357 Chee Wei Wong Ultrafast Dynamics in Graphene & Nanomaterials Joint Workshop on Nanoscience and Nanotechnology Opportunities for...

289

and Industry Dynamics  

E-Print Network (OSTI)

We assess the long-run dynamic implications of market-based regulation of carbon dioxide emissions in the US Portland cement industry. We consider several alternative policy designs, including mechanisms that use production subsidies to partially offset compliance costs and border tax adjustments to penalize emissions associated with foreign imports. Our results highlight two general countervailing market distortions. First, following Buchanan (1969), reductions in product market surplus and allocative inefficiencies due to market power in the domestic cement market counteract the social benefits of carbon abatement. Second, tradeexposure to unregulated foreign competitors leads to emissions “leakage ” which offsets domestic emissions reductions. Taken together, these forces result in social welfare losses under policy regimes that fully internalize the emissions externality. In contrast, market-based policies that incorporate design features to mitigate the exercise of market power and emissions leakage can deliver welfare gains. 1

Meredith Fowlie; Mar Reguant; Stephen P. Ryan; Meredith Fowlie; Mar Reguant; Stephen P. Ryan

2013-01-01T23:59:59.000Z

290

Dynamic Radiographic Imaging  

Science Conference Proceedings (OSTI)

A radiographic system recently developed by American and Russian collaborators is designed to capture multiple images of a dynamic event lasting less than 10 microseconds. Various optical and electro-optical components were considered and their performance compared. The final system employed a solid crystal of lutetium oxyorthosilicate doped with cerium (LSO:Ce or LSO) for X-ray-to-light conversion with a coherent fiber optic bundle to relay the scintillator image to a streak camera with charge coupled device (CCD) readout. Resolution and sensitivity studies were carried out for this system on two different sources of X-rays: a 20 MeV microtron and a 70 MeV betatron.

Volkov, A.; Turley, D.; Veeser, L.; Lukyanov, N.; Yegorov, N.; Baker, S.A.; Mirenko, V.; Lewis, W.; Kuropatkin, Y.

1999-06-01T23:59:59.000Z

291

Dynamic Vnodes - design and implementation  

Science Conference Proceedings (OSTI)

Dynamic vnodes make the UNIX kernel responsive to a varying demand for vnodes, without a need to rebuild the kernel. It also optimizes the usage of memory by deallocating excess vnodes. This paper describes the design and implementation of dynamic vnodes ...

Aju John

1995-01-01T23:59:59.000Z

292

Dynamic model for hydraulic dissipators  

Science Conference Proceedings (OSTI)

The authors propose a mathematical model of a hydraulic link with energy dissipation, the device working reversibly to the alternative traction and compression movement. The dynamic behavior of the energy hydraulic dissipater depends on the instantaneous ... Keywords: dissipater's control, dynamic behavior, hydraulic dissipater, mathematical model

Adrian S. Axinti; Gavril Axinti

2009-03-01T23:59:59.000Z

293

Fluctuations in molecular dynamics simulations  

Science Conference Proceedings (OSTI)

Statistical fluctuations of a system about its equilibrium state, monitored in a molecular dynamics simulation, are an effective means of computing the thermodynamic and kinetic properties of interfaces in metals and alloys. In this work, three applications ... Keywords: Fluctuations, Grain boundaries, Interfaces, Interfacial free energy, Mobility, Molecular dynamics

J. J. Hoyt; Z. T. Trautt; M. Upmanyu

2010-03-01T23:59:59.000Z

294

Dynamic spectrum management using GA  

Science Conference Proceedings (OSTI)

Thousands of equipments of the wireless network and the mobile devices are widely used and the demand of dynamic spectrum resources is significantly growing. How to maximize the social utility in modern technique becomes an important issue. In this paper, ... Keywords: Shannon utility, background interference, crosstalk, dynamic spectrum management, genetic algorithm

Ping-Liang Chen; Chia-Liang Peng; Shin-Jia Chen; Yu-Cheng Lin

2011-12-01T23:59:59.000Z

295

Periodicity estimation of Dynamic Textures  

Science Conference Proceedings (OSTI)

Dynamic Textures (DTs) are image sequences of natural events like fire, smoke, water etc., that possesses regular motion patterns. Periodicity is a widely used tool to analyse regular structures of periodic one dimensional signals as well as two dimensional ... Keywords: co-occurrence matrix, dynamic textures, image sequences, image texture analysis, motion patterns, natural events, periodicity estimation, temporal textures

Khalid Zaman Bijon; Ahmed Hasan; Ashfaqur Rahman; Manzur Murshed

2008-03-01T23:59:59.000Z

296

A Generic Dynamic Emulator  

E-Print Network (OSTI)

In applied sciences, we often deal with deterministic simulation models that are too slow for simulation-intensive tasks such as calibration or real-time control. In this paper, an emulator for a generic dynamic model, given by a system of ordinary non-linear differential equations, is developed. The non-linear differential equations are linearized and Gaussian white noise is added to account for the non-linearities. The resulting linear stochastic system is conditioned on a set of solutions of the non-linear equations that have been calculated prior to the emulation. A path-integral approach is used to derive the Gaussian distribution of the emulated solution. The solution reveals that most of the computational burden can be shifted to the conditioning phase of the emulator and the complexity of the actual emulation step only scales like $\\mathcal O(Nnm^2)$, where $N$ is the number of time-points at which the solution is to be emulated, $n$ the number of solutions the emulator is conditioned on and $m$ the n...

Albert, Carlo

2011-01-01T23:59:59.000Z

297

Dynamic Fault Detection Chassis  

Science Conference Proceedings (OSTI)

Abstract The high frequency switching megawatt-class High Voltage Converter Modulator (HVCM) developed by Los Alamos National Laboratory for the Oak Ridge National Laboratory's Spallation Neutron Source (SNS) is now in operation. One of the major problems with the modulator systems is shoot-thru conditions that can occur in a IGBTs H-bridge topology resulting in large fault currents and device failure in a few microseconds. The Dynamic Fault Detection Chassis (DFDC) is a fault monitoring system; it monitors transformer flux saturation using a window comparator and dV/dt events on the cathode voltage caused by any abnormality such as capacitor breakdown, transformer primary turns shorts, or dielectric breakdown between the transformer primary and secondary. If faults are detected, the DFDC will inhibit the IGBT gate drives and shut the system down, significantly reducing the possibility of a shoot-thru condition or other equipment damaging events. In this paper, we will present system integration considerations, performance characteristics of the DFDC, and discuss its ability to significantly reduce costly down time for the entire facility.

Mize, Jeffery J [ORNL

2007-01-01T23:59:59.000Z

298

ICFA Beam Dynamics Newsletter  

SciTech Connect

The Collider-Accelerator Department at Brookhaven National Laboratory is building a high-brightness 500 mA capable Energy Recovery Linac (ERL) as one of its main R&D thrusts towards eRHIC, the polarized electron - hadron collider as an upgrade of the operating RHIC facility. The ERL is in final assembly stages, with injection commisioning starting in October 2012. The objective of this ERL is to serve as a platform for R&D into high current ERL, in particular issues of halo generation and control, Higher-Order Mode (HOM) issues, coherent emissions for the beam and high-brightness, high-power beam generation and preservation. The R&D ERL features a superconducting laser-photocathode RF gun with a high quantum efficiency photoccathode served with a load-lock cathode delivery system, a highly damped 5-cell accelerating cavity, a highly flexible single-pass loop and a comprehensive system of beam instrumentation. In this ICFA Beam Dynamics Newsletter article we will describe the ERL in a degree of detail that is not usually found in regular publications. We will discuss the various systems of the ERL, following the electrons from the photocathode to the beam dump, cover the control system, machine protection etc and summarize with the status of the ERL systems.

Ben-Zvi I.; Kuczewski A.; Altinbas, Z.; Beavis, D.; Belomestnykh,; Dai, J. et al

2012-07-01T23:59:59.000Z

299

Fermionic Molecular Dynamics for nuclear dynamics and thermodynamics  

E-Print Network (OSTI)

A new Fermionic Molecular Dynamics (FMD) model based on a Skyrme functional is proposed in this paper. After introducing the basic formalism, some first applications to nuclear structure and nuclear thermodynamics are presented

K. H. O. Hasnaoui; Ph. Chomaz; F. Gulminelli

2008-12-02T23:59:59.000Z

300

The solvent dependent shift of the amide I band of a fully solvated peptide in methanol/water mixtures as a local probe for the solvent composition in the peptide/solvent interface  

DOE Green Energy (OSTI)

We determine the shift and line-shape of the amide I band of a model AK-peptide from molecular dynamics (MD) simulations of the peptide dissolved in methanol/water mixtures with varying composition. The IR-spectra are determined from a transition dipole coupling exciton model. A simplified empirical model Hamiltonian is employed, taking both the effect of hydrogen bonding, as well as intramolecular vibrational coupling into account. We consider a single isolated AK-peptide in a mostly helical conformation, while the solvent is represented by 2600 methanol or water molecules, simulated for a pressure of 1 bar and a temperature of 300 K. Over the course of the simulations minor reversible conformational changes at the termini are observed, which are found to only slightly affect the calculated spectral properties. Over the entire composition range, varying from pure water to the pure methanol solvent, a monotonous blue-shift of the IR amide I band of about 8 wavenumbers is observed. The shift is found to be caused by two counter-compensating effects: An intramolecular red-shift of about 1.2 wavenumbers, due to stronger intramolecular hydrogen-bonding in a methanol-rich environment. Dominating, however, is the intermolecular solvent-dependent blue-shift of about 10 wavenumbers, being attributed to the less effective hydrogen bond donor capabilities of methanol compared to water. The importance of solvent-contribution to the IR-shift, as well as the significantly different hydrogen formation capabilities of water and methanol make the amide I band sensitive to composition changes in the local environment close the peptide/solvent interface. This allows, in principle, an experimental determination of the composition of the solvent in close proximity to the peptide surface. For the AK-peptide case they observe at low methanol concentrations a significantly enhanced methanol concentration at the peptide/solvent-interface, supposedly promoted by the partially hydrophobic character of the AK-peptide's solvent accessible surface.

Gnanakaran, S [Los Alamos National Laboratory

2008-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "ultrafast solvation dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Complex Crystallization Dynamics in Amorphous Germanium ...  

Science Conference Proceedings (OSTI)

We used dynamic transmission electron microscopy [2] to study in situ this fast dynamics ... of Magnetism in Multiferroic Heterostructures and Low-power Devices ...

302

16.07 Dynamics, Fall 2004  

E-Print Network (OSTI)

Dynamics starts with fundamentals of Newtonian mechanics. Further topics include kinematics, particle dynamics, motion relative to accelerated reference frames, work and energy, impulse and momentum, systems of particles ...

Peraire, Jaume

303

Molecular dynamics simulations and drug discovery  

E-Print Network (OSTI)

JE: On the determination of molecular fields. II. From thescalability for parallel molecular dynamics. J Comput PhysKale L, Schulten K: Scalable molecular dynamics with NAMD. J

Durrant, Jacob D; McCammon, J Andrew

2011-01-01T23:59:59.000Z

304

Dynamic stall on wind turbine blades  

DOE Green Energy (OSTI)

Dynamic loads must be predicted accurately in order to estimate the fatigue life of wind turbines operating in turbulent environments. Dynamic stall contributes to increased dynamic loads during normal operation of all types of horizontal-axis wind turbine (HAWTs). This report illustrates how dynamic stall varies throughout the blade span of a 10 m HAWT during yawed and unyawed operating conditions. Lift, drag, and pitching moment coefficients during dynamics stall are discussed. Resulting dynamic loads are presented, and the effects of dynamic stall on yaw loads are demonstrated using a yaw loads dynamic analysis (YAWDYN). 12 refs., 22 figs., 1 tab.

Butterfield, C.P.; Simms, D.; Scott, G. [National Renewable Energy Lab., Golden, CO (United States)] [National Renewable Energy Lab., Golden, CO (United States); Hansen, A.C. [Utah Univ., Salt Lake City, UT (United States)] [Utah Univ., Salt Lake City, UT (United States)

1991-12-01T23:59:59.000Z

305

Femtosecond photoelectron spectroscopy: a new tool for the study of anion dynamics  

SciTech Connect

A new experimental technique for the time-resolved study of anion reactions is presented. Using femtosecond laser pulses, which provide extremely fast ({approx} 100 fs) time resolution, in conjunction with photoelectron spectroscopy, which reveals differences between anion and neutral potential energy surfaces, a complex anion reaction can be followed from its inception through the formation of asymptotic products. Experimental data can be modeled quantitatively using established theoretical approaches, allowing for the refinement of potential energy surfaces as well as dynamical models. After a brief overview, a detailed account of the construction of the experimental apparatus is presented. Documentation of the data acquisition program is contained in the Appendix. The first experimental demonstration of the technique is then presented for I{sub 2}{sup -} photodissociation, modeled using a simulation program which is also detailed in the Appendix. The investigation of I{sub 2}{sup -} photodissociation in several size-selected I{sub 2}{sup -}(Ar){sub n} (n = 6-20) and I{sub 2}{sup -}(CO{sub 2}){sub n} (n = 4-16) clusters forms the heart of the dissertation. In a series of chapters, the numerous effects of solvation on this fundamental bond-breaking reaction are explored, the most notable of which is the recombination of I{sub 2}{sup -} on the ground {tilde X}({sup 2}{Sigma}{sub u}{sup +}) state in sufficiently large clusters. Recombination and trapping of I{sub 2}{sup -} on the excited {tilde A}({sup 2}{Pi}{sub 3/2,g}) state is also observed in both types of clusters. The studies have revealed electronic state transitions, the first step in recombination, on a {approx}500 fs to {approx}10 ps timescale. Accompanying the changes in electronic state is solvent reorganization, which occurs on a similar timescale. Over longer periods ({approx}1 ps to >200 ps), energy is transferred from vibrationally excite d I{sub 2}{sup -} to modes of the solvent, which in turn leads to solvent evaporation. These effects become more important as cluster size increases. In addition, differences in timescale and mechanism are observed between clusters of Ar, which binds to I{sup -} and I{sub 2}{sup -} rather weakly, and CO{sub 2}, whose large quadruple moment allows substantially stronger binding to these anions.

Greenblatt, B.J.

1999-02-01T23:59:59.000Z

306

The power of dynamic pricing  

SciTech Connect

Using data from a generic California utility, it can be shown that it is feasible to develop dynamic pricing rates for all customer classes. These rates have the potential to reduce system peak demands from 1 to 9 percent. (author)

Faruqui, Ahmad; Hledik, Ryan; Tsoukalis, John

2009-04-15T23:59:59.000Z

307

Dynamical Predictability of Monthly Means  

Science Conference Proceedings (OSTI)

We have attempted to determine the theoretical upper limit of dynamical predictability of monthly means for prescribed nonfluctuating external forcings. We have extended the concept of “classical” predictability, which primarily refers to the ...

J. Shukla

1981-12-01T23:59:59.000Z

308

LANL | Physics | Dynamic Plutonium Experiments  

NLE Websites -- All DOE Office Websites (Extended Search)

Dynamic plutonium experiments Dynamic plutonium experiments Since the end of nuclear testing the nation has had to rely on sophisticated computer models to ensure the safety and reliability of the nuclear weapons stockpile. This program is known as science-based stockpile stewardship. Despite possessing the world's fastest computers and most advanced modeling capability, the behavior of materials under dynamic loads that occur in a nuclear weapon are difficult to accurately model. The Dynamic Plutonium experimental program carries out experiments at the Nevada National Security Site on plutonium driven by high explosives. These experiments are needed to measure and understand the behavior of plutonium under extreme conditions. Physics Division has unique capabilities in high-speed x-ray imaging and velocimetry (measuring the

309

Stochastic Dynamics of Baroclinic Waves  

Science Conference Proceedings (OSTI)

The maintenance of variance and attendant heat flux in linear, forced, dissipative baroclinic shear flows subject to stochastic excitation is examined. The baroclinic problem is intrinsically nonnormal and its stochastic dynamics is found to ...

Brian F. Farrell; Petros J. Ioannou

1993-12-01T23:59:59.000Z

310

Essays on dynamic sales mechanisms  

E-Print Network (OSTI)

This thesis is a collection of three essays on dynamic sales mechanisms. The first chapter analyzes the Name Your Own Price (NYOP) mechanism adopted by Priceline.com. Priceline.com, a website helping travelers obtain ...

Chen, Chia-Hui, Ph. D. Massachusetts Institute of Technology

2009-01-01T23:59:59.000Z

311

Dynamical Processes of Block Evolution  

Science Conference Proceedings (OSTI)

The dynamical processes associated with block evolution are investigated by analyzing a GCM run, forced with perpetual January conditions. The core of the analysis lies on the temporal evolution of the blocks and on vorticity budget terms ...

Benjamin A. Cash; Sukyoung Lee

2000-10-01T23:59:59.000Z

312

Ensemble Dynamics and Bred Vectors  

Science Conference Proceedings (OSTI)

The new concept of an ensemble bred vector (EBV) algorithm is introduced to assess the sensitivity of model outputs to changes in initial conditions for weather forecasting. The new algorithm is based on collective dynamics in essential ways. As ...

Nusret Balci; Anna L. Mazzucato; Juan M. Restrepo; George R. Sell

2012-07-01T23:59:59.000Z

313

Dynamic Pricing: A learning Approach  

E-Print Network (OSTI)

We present an optimization approach for jointly learning the demand as a functionof price, and dynamically setting prices of products in an oligopoly environment in order to maximize expected revenue. The models we consider ...

Bertsimas, Dimitris J.

314

Dynamic Mercury Cycling Model Upgrade  

Science Conference Proceedings (OSTI)

This technical update describes the status of activities to upgrade the Dynamic Mercury Cycling Model (D-MCM), an EPRI simulation model that predicts mercury cycling and bioaccumulation in lakes.

2008-12-17T23:59:59.000Z

315

Adding dynamic types to C  

Science Conference Proceedings (OSTI)

Developers using statically typed languages such as C? and Java are increasingly having to interoperate with APIs and object models defined in dynamic languages. This impedance mismatch results in code that is difficult to understand, awkward to ...

Gavin Bierman; Erik Meijer; Mads Torgersen

2010-06-01T23:59:59.000Z

316

Dynamic Graphics Using Quasi Parallelism  

E-Print Network (OSTI)

Dynamic computer graphics is best represented as several processes operating in parallel. Full parallel processing, however, entails much complex mechanism making it difficult to write simple, intuitive programs for ...

Kahn, Kenneth M.

1978-06-01T23:59:59.000Z

317

Theoretical Experiments on Cumulus Dynamics  

Science Conference Proceedings (OSTI)

The sensitivity of a two-dimensional cloud model to changes in microphysical characteristics was examined using two soundings. The dynamical evolution of clouds having relatively warm bases was controlled more by rapidity of the production of ...

L. Randall Koenig; Francis W. Murray

1983-05-01T23:59:59.000Z

318

Quasigeostrophic Dynamics of the Tropopause  

Science Conference Proceedings (OSTI)

The dynamical properties of potential temperature anomalies on the tropopause are analyzed for quasigeo-strophic flow on an f plane. The potential vorticity is taken to he piecewise constant, with a single discontinuity at the tropopause. The ...

Martin Juckes

1994-10-01T23:59:59.000Z

319

THz Dynamic Nuclear Polarization NMR  

E-Print Network (OSTI)

Dynamic nuclear polarization (DNP) increases the sensitivity of nuclear magnetic resonance (NMR) spectroscopy by using high frequency microwaves to transfer the polarization of the electrons to the nuclear spins. The ...

Nanni, Emilio Alessandro

320

EPRI Power System Dynamics Tutorial  

Science Conference Proceedings (OSTI)

Operation of today's increasingly complex power systems requires comprehensive training of system operators and operations engineers. By increasing their awareness and understanding of dynamic phenomena, the EPRI Power System Dynamics Tutorial can improve an operator's ability to take effective actioneither preventive or corrective. This latest version of the tutorial represents an update of key topics to reflect industry restructuring under the vision of the Federal Energy Regulatory Commission (FERC) a...

2009-07-27T23:59:59.000Z

Note: This page contains sample records for the topic "ultrafast solvation dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Dynamic modeling of power systems  

Science Conference Proceedings (OSTI)

Morgantown Energy Technology Center`s (METC) Process and Project Engineering (P&PE) personnel continue to refine and modify dynamic modeling or simulations for advanced power systems. P&PE, supported by Gilbert/Commonwealth, Inc. (G/C), has adapted PC/TRAX commercial dynamic software to include equipment found in advanced power systems. PC/TRAX`s software contains the equations that describe the operation of standard power plant equipment such as gas turbines, feedwater pumps, and steam turbines. The METC team has incorporated customized dynamic models using Advanced Continuous Simulation Language (ACSL) code for pressurized circulating fluidized-bed combustors, carbonizers, and other components that are found in Advanced Pressurized Fluidized-Bed Combustion (APFBC) systems. A dynamic model of a commercial-size APFBC power plant was constructed in order to determine representative operating characteristics of the plant and to gain some insight into the best type of control system design. The dynamic model contains both process and control model components. This presentation covers development of a model used to describe the commercial APFBC power plant. Results of exercising the model to simulate plant performance are described and illustrated. Information gained during the APFBC study was applied to a dynamic model of a 1-1/2 generation PFBC system. Some initial results from this study are also presented.

Reed, M.; White, J.

1995-12-01T23:59:59.000Z

322

HAWT performance with dynamic stall  

DOE Green Energy (OSTI)

In this report we calculated the effects of flow nonuniformities (wing shear, tower wake, yaw, and large-scale turbulence) on the performance of a horizontal axis wind turbine, accounting for dynamic stall. We modified the PROP program to incorporate and compare these effects with the uniform flow case. The MIT model, which predicts dynamic lift coefficients substantially higher than the static maximum values and includes a crude model of the vortex roll-off phenomenon, represented dynamic stall. As associated model for drag was also used. The dynamic stall model was tested against experimental data for three typical reduced frequencies. Good instantaneous correlation was obtained. The effects of nonuniformities with and without the dynamic stall were calculated using the Westinghouse Mod O and Enertech 44/25 turbines. Modeling the dynamic stall has little effect on performance. Furthermore, the performance with nonuniform flow differed only slightly from the uniform flow case. Thus the now PROP model provides a powerful general capability to handle nonuniform flows.

Hibbs, B.D.

1986-02-01T23:59:59.000Z

323

Projected dynamical systems in a complementarity formalism  

Science Conference Proceedings (OSTI)

Projected dynamical systems have been introduced by Dupuis and Nagurney as dynamic extensions of variational inequalities. In the systems and control literature, complementarity systems have been studied as input/output dynamical systems whose inputs ... Keywords: Complementarity, Discontinuous dynamical systems, Optimization, Systems theory, Variational inequalities

W. P. M. H. Heemels; J. M. Schumacher; S. Weiland

2000-09-01T23:59:59.000Z

324

Simple Dynamic Gasifier Model That Runs in Aspen Dynamics  

SciTech Connect

Gasification (or partial oxidation) is a vital component of 'clean coal' technology. Sulfur and nitrogen emissions can be reduced, overall energy efficiency is increased, and carbon dioxide recovery and sequestration are facilitated. Gasification units in an electric power generation plant produce a fuel for driving combustion turbines. Gasification units in a chemical plant generate gas, which can be used to produce a wide spectrum of chemical products. Future plants are predicted to be hybrid power/chemical plants with gasification as the key unit operation. The widely used process simulator Aspen Plus provides a library of models that can be used to develop an overall gasifier model that handles solids. So steady-state design and optimization studies of processes with gasifiers can be undertaken. This paper presents a simple approximate method for achieving the objective of having a gasifier model that can be exported into Aspen Dynamics. The basic idea is to use a high molecular weight hydrocarbon that is present in the Aspen library as a pseudofuel. This component should have the same 1:1 hydrogen-to-carbon ratio that is found in coal and biomass. For many plantwide dynamic studies, a rigorous high-fidelity dynamic model of the gasifier is not needed because its dynamics are very fast and the gasifier gas volume is a relatively small fraction of the total volume of the entire plant. The proposed approximate model captures the essential macroscale thermal, flow, composition, and pressure dynamics. This paper does not attempt to optimize the design or control of gasifiers but merely presents an idea of how to dynamically simulate coal gasification in an approximate way.

Robinson, P.J.; Luyben, W.L. [Lehigh University, Bethlehem, PA (United States). Dept. of Chemical Engineering

2008-10-15T23:59:59.000Z

325

DYNAMIC SCREENING IN SOLAR PLASMA  

Science Conference Proceedings (OSTI)

In the hot, dense plasma of solar and stellar interiors, Coulomb potentials are screened, resulting in increased nuclear reaction rates. Although Salpeter's approximation for static screening is widely accepted and used in stellar modeling, the question of screening in nuclear reactions has been revisited. In particular, the issue of dynamic effects has been raised by Shaviv and Shaviv who apply the techniques of molecular dynamics to the conditions in the Sun's core in order to numerically determine the effect of screening. By directly calculating the motion of ions and electrons due to Coulomb interactions, the simulations are used to compute the effect of screening without the mean field assumption inherent in Salpeter's approximation. In this paper, we reproduce their numerical analysis of the screening energy in the plasma of the solar core and conclude that the effects of dynamic screening are relevant and should be included when stellar nuclear reaction rates are computed.

Mao, Dan; Daeppen, Werner [Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089 (United States); Mussack, Katie [Institute of Astronomy, University of Cambridge, Cambridge CB3 0HA (United Kingdom)], E-mail: mussack@ast.cam.ac.uk

2009-08-20T23:59:59.000Z

326

Nonlinear Fluid Dynamics from Gravity  

E-Print Network (OSTI)

Black branes in AdS5 appear in a four parameter family labeled by their velocity and temperature. Promoting these parameters to Goldstone modes or collective coordinate fields -- arbitrary functions of the coordinates on the boundary of AdS5 -- we use Einstein's equations together with regularity requirements and boundary conditions to determine their dynamics. The resultant equations turn out to be those of boundary fluid dynamics, with specific values for fluid parameters. Our analysis is perturbative in the boundary derivative expansion but is valid for arbitrary amplitudes. Our work may be regarded as a derivation of the nonlinear equations of boundary fluid dynamics from gravity. As a concrete application we find an explicit expression for the expansion of this fluid stress tensor including terms up to second order in the derivative expansion.

Sayantani Bhattacharyya; Veronika E Hubeny; Shiraz Minwalla; Mukund Rangamani

2007-12-14T23:59:59.000Z

327

Ab-Initio Molecular Dynamics  

E-Print Network (OSTI)

Computer simulations and molecular dynamics in particular, is a very powerful method to provide detailed and essentially exact informations of classical many-body problems. With the advent of \\textit{ab-initio} molecular dynamics, where the forces are computed on-the-fly by accurate electronic structure calculations, the scope of either method has been greatly extended. This new approach, which unifies Newton's and Schr\\"odinger's equations, allows for complex simulations without relying on any adjustable parameter. This review is intended to outline the basic principles as well as a survey of the field. Beginning with the derivation of Born-Oppenheimer molecular dynamics, the Car-Parrinello method as well as novel hybrid scheme that unifies best of either approach are discussed. The predictive power is demonstrated by a series of applications ranging from insulators to semiconductors and even metals in condensed phases.

Kühne, Thomas D

2012-01-01T23:59:59.000Z

328

Dynamic screening in solar plasma  

E-Print Network (OSTI)

In the hot, dense plasma of solar and stellar interiors, Coulomb potentials are screened, resulting in increased nuclear reaction rates. Although Salpeter's approximation for static screening is widely accepted and used in stellar modeling, the question of screening in nuclear reactions has been revisited. In particular the issue of dynamic effects has been raised by Shaviv and Shaviv who apply the techniques of molecular dynamics to the conditions in the Sun's core in order to numerically determine the effect of screening. By directly calculating the motion of ions and electrons due to Coulomb interactions, the simulations are used to compute the effect of screening without the mean-field assumption inherent in Salpeter's approximation. In this paper we reproduce their numerical analysis of the screening energy in the plasma of the solar core and conclude that the effects of dynamic screening are relevant and should be included when stellar nuclear reaction rates are computed.

Mao, Dan; Däppen, Werner

2009-01-01T23:59:59.000Z

329

A multipulsed dynamic moire interferometer  

DOE Patents (OSTI)

An improved dynamic moire interferometer is described that is comprised of a lasing medium providing a plurality of beams of coherent light, a multiple q-switch producing multiple trains of 100,000 or more pulses per second, a combining means collimating multiple trains of pulses into substantially a single train and directing beams to specimen gratings affixed to a test material, and a controller, triggering and sequencing the emission of the pulses with the occurrence and recording of a dynamic loading event. 5 figs.

Deason, V.A.

1989-06-10T23:59:59.000Z

330

Fairness and dynamic pricing: comments  

Science Conference Proceedings (OSTI)

In ''The Ethics of Dynamic Pricing,'' Ahmad Faruqui lays out a case for improved efficiency in using dynamic prices for retail electricity tariffs and addresses various issues about the distributional effects of alternative pricing mechanisms. The principal contrast is between flat or nearly constant energy prices and time-varying prices that reflect more closely the marginal costs of energy and capacity. The related issues of fairness criteria, contracts, risk allocation, cost allocation, means testing, real-time pricing, and ethical policies of electricity market design also must be considered. (author)

Hogan, William W.

2010-07-15T23:59:59.000Z

331

Nonlinear manifold learning for dynamic shape and dynamic appearance  

Science Conference Proceedings (OSTI)

Our objective is to learn representations for the shape and the appearance of moving (dynamic) objects that support tasks such as synthesis, pose recovery, reconstruction, and tracking. In this paper, we introduce a framework that aims to learn landmark-free ... Keywords: Appearance-based vision, Gait analysis, Human motion analysis, Manifold learning, Motion analysis, Shape analysis

Ahmed Elgammal; Chan-Su Lee

2007-04-01T23:59:59.000Z

332

Proceedings of the Seventeenth DOE Solar Photochemistry Research Conference  

DOE Green Energy (OSTI)

The Seventeenth DOE Solar Photochemistry Research Conference sponsored by the Division of Chemical Sciences, Office of Basic Energy Sciences, is being held June 6--10, 1993, at Cragun`s Lodge and Conference Center, Brainerd, Minnesota The meeting is hosted this year by the Ames Laboratory of Iowa State University. The purpose of the meeting is to foster cooperation, collaboration, and exchange of current research ideas among grantees and contractors of the DOE Division of Chemical Sciences engaged in fundamental research on solar photochemical energy conversion. This conference provides a special opportunity for interaction among investigators from diverse traditional chemistry disciplines who share the common good of providing the knowledge and concepts needed for production of low cost fuels and chemicals or electricity by photochemical conversion of solar energy. Our special guest plenary lecturer is Professor Graham Fleming, of the University of Chicago, who will speak on ultrafast spectroscopic studies of molecular dynamics in the condensed phase. The remaining presentations on Monday will feature further investigations of ultrafast phenomena in solvation, electron transfer, and charge separation at interfaces. These will lead into the topical sessions which follow on photosynthesis, molecular models, photoinduced charge transfer in homogeneous and heterogeneous solutions, inorganic photochemistry, and photoelectrochemistry. As an added feature, the photoelectrochemistry session will include six short introductory lectures for the benefit of nonspecialists on outstanding issues and problems in that field. In this volume may be found a copy of the program, the abstracts of 28 formal presentations and 59 posters, as well as an address listing of the 114 participants.

Not Available

1993-12-31T23:59:59.000Z

333

Observation of a remarkable temperature effect in the hydrogen bonding structure and dynamics of the CN-(H2O) cluster  

DOE Green Energy (OSTI)

The CN-(H2O) cluster represents a model diatomic monohydrate with multiple solvation sites. We report joint experimental and theoretical studies of its structure and dynamics using temperature-controlled photoelectron spectroscopy (PES) and ab-initio electronic structure calculations. The observed PES spectra of CN-(H2O) display a remarkable temperature effect, namely that the T=12 K spectrum shows an unexpectedly large blue shift of 0.25 eV in the electron binding energy relative to the Room Temperature (RT) spectrum. Extensive theoretical analysis of the potential energy function (PEF) of the cluster at the CCSD(T) level of theory reveal the existence of two nearly isoenergetic isomers corresponding to H2O forming a H-bond with either the C or the N atom, respectively. This results in four topologically distinct minima, i.e., CN-(HaOHb), CN-(HbOHa), NC-(HaOHb) and NC-(HbOHa). There are two main pathways connecting these minima: (i) CN- tumbling relative to water and (ii) water rocking relative to CN-. The relative magnitude of the barriers associated with these two motions reverses between low [pathway (i) is preferred] and high [pathway (ii) is preferred] temperatures. As a result, at T=12 K the cluster adopts a structure that is close to the minimum energy CN-(H2O) configuration, while at RT it can effectively access regions of the PEF close to the transition state for pathway (ii), explaining the surprisingly large spectral shift between the 12 K and RT PES spectra. This work was supported by the Division of Chemical Sciences, Geosciences and Biosciences, Office of Basic Energy Sciences, US Department of Energy. Battelle operates Pacific Northwest National Laboratory for the US Department of Energy.

Wang, Xue B.; Werhahn, Jasper C.; Wang, Lai S.; Kowalski, Karol; Laubereau, Alfred; Xantheas, Sotiris S.

2009-09-03T23:59:59.000Z

334

Dynamic Scheduling via Polymatroid Optimization  

Science Conference Proceedings (OSTI)

Dynamic scheduling of multi-class jobs in queueing systems has wide ranging applications, but in general is a very difficult control problem. Here we focus on a class of systems for which conservation laws hold. Consequently, the performance space becomes ...

David D. Yao

2002-01-01T23:59:59.000Z

335

Environmental design using dynamic insulation  

SciTech Connect

In conventional airtight buildings, the architect has considerable freedom to decide how much the external environment will influence the internal heating, cooling, and ventilation loads. The services engineer provides the plant and equipment required to deal with these loads. This division of labor could lead to undesirable consequences in the case of dynamic insulation, a form of air permeable construction where bulk air flow through the building envelope may be used to either enhance or restrict the conductive heat and mass diffusion fluxes. Small changes in temperature (indoor and out) and wind speed and direction will influence the behavior of a dynamically insulated envelope since the internal and external environments are much more intimately coupled. Buildings employing dynamic insulation thus require good environmental design principles to be applied. The objective of this paper is to lay down rigorous principles that will form the basis of guidelines to architects and building services engineers on how to take account of the ever changing external environment when designing durable and comfortable buildings employing dynamic insulation.

Taylor, B.J.; Imbabi, M.S.

2000-07-01T23:59:59.000Z

336

Conspicuous Consumption and Dynamic Pricing  

Science Conference Proceedings (OSTI)

How do firms develop marketing strategy when consumers seek to satisfy both quality and status-related considerations? We develop an analytical model to study this issue, examining both pricing and product management decisions in markets for conspicuous ... Keywords: conspicuous consumption, durable goods, dynamic pricing, game theory, status

Raghunath Singh Rao, Richard Schaefer

2013-09-01T23:59:59.000Z

337

Dynamical genetic programming in xcsf  

Science Conference Proceedings (OSTI)

A number of representation schemes have been presented for use within learning classifier systems, ranging from binary encodings to artificial neural networks. This paper presents results from an investigation into using a temporally dynamic symbolic ... Keywords: Graph-based genetic programming, XCSF, learning classifier systems, multistep-ahead prediction, reinforcement learning, self-adaptation, symbolic regression

Richard J. Preen, Larry Bull

2013-09-01T23:59:59.000Z

338

Dynamic virtual credit card numbers  

Science Conference Proceedings (OSTI)

Theft of stored credit card information is an increasing threat to e-commerce.We propose a dynamic virtual credit card number scheme that reduces the damage caused by stolen credit card numbers. A user can use an existing credit card account to generate ... Keywords: credit card theft, e-commerce

Ian Molloy; Jiangtao Li; Ninghui Li

2007-02-01T23:59:59.000Z

339

Ultrafast Spectroscopy of Warm Dense Matter  

NLE Websites -- All DOE Office Websites (Extended Search)

of planet formation and structures as well as the evolution of an imploding inertial fusion capsule depends on our understanding of matter in the complex warm dense matter...

340

NIST Ultrafast Terahertz Spectroscopy and Imaging  

Science Conference Proceedings (OSTI)

... THz spectrometer for spectral determinations of samples (0.2 to 10 THz) and transient spectroscopy of bimolecular, photovoltaic, and materials ...

2013-09-20T23:59:59.000Z

Note: This page contains sample records for the topic "ultrafast solvation dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Ultrafast optics For optics and photonics course,  

E-Print Network (OSTI)

techniques or mode locking methods, 4/12/2012 2Liquid Crystal Institute #12;· Light bulbs, lasers lets some light out. R = 100% R #12;· Laser cavity modes: · Although laser light is perhaps the purest form of light

Palffy-Muhoray, Peter

342

Ultrafast thermal cycling of solar panels  

SciTech Connect

Two new cyclers that utilize a novel hybrid approach to perform fast thermal cycling of solar panels have been built and are now operational in the Mechanics and Materials Technology Center at The Aerospace Corporation. These cyclers are part of a continuing effort to minimize solar cell life test durations by accelerating the cycling rates. These fully automated cyclers, which provide continuous unmanned cycling in a gaseous nitrogen atmosphere, can execute 5 min cycles, thus yielding in excess of 100,000 cycles per year. They also have a unique capability of verifying solar panel functionality without interruption of cycling, so that cycling doesn`t continue on nonfunctioning panels.

Wall, T.S.; Valenzuela, P.R.; Sue, C.

1998-08-15T23:59:59.000Z

343

AN ULTRAFAST FOURIER TRANSFORM PARALLEL PROCESSOR  

E-Print Network (OSTI)

that uses the UFTPP 2-D processor of Filtered Projectionsprojections algorithm are The cited. be Assisted operation.Image Reconstruction from Projections Conclusion REFERENCES

Greenberg, W.L.

2013-01-01T23:59:59.000Z

344

The Reorientation Mechanism of Hydroxide Ions in Water: A Molecular Dynamics Study  

DOE Green Energy (OSTI)

simulations with polarizable potential models. Two major solvation structures of OH- were suggested by our study. One of which has four accepted hydrogen bonds from water and the other has five accepted hydrogen bonds. A weak hydrogen bond donated by the hydroxide ion was observed in our simulations. The simulated reorientation relaxation times of OH- are in qualitative agreement with CTTS experiments. We propose a two-step mechanism for the reorientation of hydroxide ions in water. First, the reorientation of OH- is initiated by the coupled translation with water molecules in its first solvation shell. Second, the OH- hydrogen relaxes to the minimum energy state. The rate-limiting step in this mechanism is the first step, translation diffusion of the first solvation shell water molecules. The activation energies of reorientation of OH- and translation of H2O determined from our simulations are 22.5 and 18.5 kJ/mol, respectively. These values fall in the range of the measured data. This work was supported by the US Department of energy's Office of Basic Energy Sciences, Chemical Sciences program. Pacific Northwest national Laboratory is operated by Battelle for the US Department of Energy.

Sun, Xiuquan; Yoo, Soohaeng; Xantheas, Sotiris S.; Dang, Liem X.

2009-10-19T23:59:59.000Z

345

NIST Quantum Physics Division - 2005-2007: Strategic Focus ...  

Science Conference Proceedings (OSTI)

... Third. Ultrafast Science - to advance ultrafast science. ... Ultrafast Science: to advance ultrafast science. INTENDED OUTCOME AND BACKGROUND. ...

346

Efficient Multiagent Coordination in Dynamic Environments  

Science Conference Proceedings (OSTI)

Agent coordination is a fundamental task in designing and operating multiagent systems. However, in dynamically changing environments, coordination must balance proactive and reactive behaviors in order to enable efficient operations while retaining ... Keywords: multiagent coordination, dynamics, adaption, social order generation

Jan Ole Berndt; Otthein Herzog

2011-08-01T23:59:59.000Z

347

A dynamic semantics of intentional identity  

Science Conference Proceedings (OSTI)

This paper will propose a new version of Dynamic Modal Predicate Logic (DMPL) to treat dynamics of intentional identity [1] and other similar notions such as weak intentional identity and multiple intentional identity by revising the DMPL of modal subordination ...

Norihiro Ogata

2006-06-01T23:59:59.000Z

348

System dynamics simulation of the telecom industry  

E-Print Network (OSTI)

The primary goal of this research effort was to integrate several pieces of relatively simple dynamics simulations into a full blown system dynamics simulation of the telecom industry. The economic simulation model was ...

Shapira, Gil, 1971-

2004-01-01T23:59:59.000Z

349

Dynamic archive evolution strategy for multiobjective optimization  

Science Conference Proceedings (OSTI)

This paper proposes a new multiobjective evolutionary approach—the dynamic archive evolution strategy (DAES) to investigate the adaptive balance between proximity and diversity. In DAES, a novel dynamic external archive is proposed to store elitist ...

Yang Shu Min; Shao Dong Guo; Luo Yang Jie

2005-03-01T23:59:59.000Z

350

A generative model for dynamic canvas motion  

Science Conference Proceedings (OSTI)

We present techniques for constructing realistic canvas and paper models and for enabling interactive dynamic canvas motion. Dynamic canvas motion means that there is a correspondence between the motion of canvas features and the motion of the models ...

Matthew Kaplan; Elaine Cohen

2005-05-01T23:59:59.000Z

351

Mathematics 658 Nonlinear Dynamics and Mechanics  

E-Print Network (OSTI)

Mathematics 658 Nonlinear Dynamics and Mechanics Instructor: Anthony M. Bloch. Office: 4842 East differential equations and dynamical systems, with applications to various mechanical and physical systems, nonlinear stability theory, Lagrangian and Hamiltonian mechanics, integrable systems, reduction

Bloch, Anthony

352

Lab experiences for teaching undergraduate dynamics  

E-Print Network (OSTI)

This thesis describes several projects developed to teach undergraduate dynamics and controls. The materials were developed primarily for the class 2.003 Modeling Dynamics and Control I. These include (1) a set of ActivLab ...

Lilienkamp, Katherine A. (Katherine Ann), 1969-

2003-01-01T23:59:59.000Z

353

A Nonlinear Dynamical Perspective on Climate Prediction  

Science Conference Proceedings (OSTI)

A nonlinear dynamical perspective on climate prediction is outlined, based on a treatment of climate as the attractor of a nonlinear dynamical system D with distinct quasi-stationary regimes. The main application is toward anthropogenic climate ...

T. N. Palmer

1999-02-01T23:59:59.000Z

354

DYNAMIC APERTURE OF THE ALS BOOSTER SYNCHROTRON  

E-Print Network (OSTI)

Nelson, "Magnetic Properties of the ALS noosler Synchrotron23,1989 Dynamic Aperture of the ALS Booster Synchrotron C.H.DYNAMIC APERTURE OF TIlE ALS BOOSTER SYNCIIROlRON· CharI""

Kim, C.H.

2010-01-01T23:59:59.000Z

355

Dynamic Demand Input Preparation for Planning Applications  

E-Print Network (OSTI)

model to the ground truth Table 3-2 summarizes the Meanground truth and in preparing the seed dynamic OD table inground truth and the one in preparing seed dynamic OD tables

Jintanakul, Klayut

2009-01-01T23:59:59.000Z

356

Optimization of naïve dynamic binary instrumentation Tools/  

E-Print Network (OSTI)

The proliferation of dynamic program analysis tools has done much to ease the burden of developing complex software. However, creating such tools remains a challenge. Dynamic binary instrumentation frameworks such as ...

Kleckner, Reid (Reid N.)

2011-01-01T23:59:59.000Z

357

Bayesian inference of stochastic dynamical models  

E-Print Network (OSTI)

A new methodology for Bayesian inference of stochastic dynamical models is developed. The methodology leverages the dynamically orthogonal (DO) evolution equations for reduced-dimension uncertainty evolution and the Gaussian ...

Lu, Peter Guang Yi

2013-01-01T23:59:59.000Z

358

Ocean dynamics and thermodynamics in the tropical Indo- Pacific region  

E-Print Network (OSTI)

Ocean dynamics and thermodynamics in the tropical Indo-Ocean dynamics and thermodynamics in the tropical Indo-affect the dynam- ics and thermodynamics of the upper ocean.

Drushka, Kyla

2011-01-01T23:59:59.000Z

359

Forecasting with Dynamic Microsimulation: Design, Implementation, and Demonstration  

E-Print Network (OSTI)

Goulias Page 84 Forecasting with Dynamic Microsimulation:Goulias Page 80 Forecasting with Dynamic Microsimulation:L. Demographic Forecasting with a Dynamic Stochastic

Ravulaparthy, Srinath; Goulias, Konstadinos G.

2011-01-01T23:59:59.000Z

360

Iterated dynamical maps in an ion trap  

E-Print Network (OSTI)

Iterated dynamical maps offer an ideal setting to investigate quantum dynamical bifurcations and are well adapted to few-qubit quantum computer realisations. We show that a single trapped ion, subject to periodic impulsive forces, exhibits a rich structure of dynamical bifurcations derived from the Jahn-Teller Hamiltonian flow model. We show that the entanglement between the oscillator and electronic degrees of freedom reflects the underlying dynamical bifurcation in a Floquet eigenstate.

M. Duncan; J. Links; G. J. Milburn

2007-11-16T23:59:59.000Z

Note: This page contains sample records for the topic "ultrafast solvation dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Dynamic Measurement of Hydraulic Parameters Under Liquid ...  

Search PNNL. PNNL Home; About; Research; Publications; Jobs; News; Contacts; Dynamic Measurement of Hydraulic Parameters Under Liquid Unsaturated Flow ...

362

Dynamic Links and Distributed Computing - CECM  

E-Print Network (OSTI)

Dynamic Links and Distributed Computing ... Next: Advanced Collaboration via Up: InternetExecutable Content, Previous: The Third-Generation Internet ...

363

Information Relaxations, Duality, and Convex Dynamic Programs  

E-Print Network (OSTI)

Oct 15, 2013 ... Abstract: We consider the information relaxation approach for calculating performance bounds for stochastic dynamic programs (DPs), ...

364

Molecular Dynamics Simulations of Thermoset Polymers for ...  

Science Conference Proceedings (OSTI)

Materials Genomics Past & Future: From CALPHAD to Flight · Modelling the Properties of Multi-Component Commercial Alloys · Molecular Dynamics ...

365

Risk-Averse Stochastic Dual Dynamic Programming  

E-Print Network (OSTI)

Feb 27, 2013 ... dynamic programming for hydroelectricity generation, Technical report, Electric Power Opti- mization Centre, University of Auckland, ...

366

PUBSAT and NERVA launcher fuel sloshing dynamics  

Science Conference Proceedings (OSTI)

Structural dynamics of the NERVA orbital launcher and of the PUBSAT nanosatellite is presented, with emphasize on loading definition including dynamic effects of liquid sloshing phenomena in the propellant tanck. Mainly subjected to considerable longitudinal ... Keywords: flight control, flight dynamics, fuel sloshing, satellites launcher, stability of motion

Radu D. Rugescu; Ion Predoiu; Sorin Aldea

2008-06-01T23:59:59.000Z

367

Stochastic Event-Driven Molecular Dynamics  

Science Conference Proceedings (OSTI)

A novel Stochastic Event-Driven Molecular Dynamics (SEDMD) algorithm is developed for the simulation of polymer chains suspended in a solvent. SEDMD combines event-driven molecular dynamics (EDMD) with the Direct Simulation Monte Carlo (DSMC) method. ... Keywords: Complex flow, DSMC, Event-driven molecular dynamics, Polymer suspension

Aleksandar Donev; Alejandro L. Garcia; Berni J. Alder

2008-02-01T23:59:59.000Z

368

Predicting locality phases for dynamic memory optimization  

Science Conference Proceedings (OSTI)

Dynamic data, cache, and memory adaptation can significantly improve program performance when they are applied on long continuous phases of execution that have dynamic but predictable locality. To support phase-based adaptation, this paper defines the ... Keywords: Dynamic optimization, Locality analysis and optimization, Phase hierarchy, Program phase prediction, Reconfigurable architecture

Xipeng Shen; Yutao Zhong; Chen Ding

2007-07-01T23:59:59.000Z

369

A thread calculus with molecular dynamics  

Science Conference Proceedings (OSTI)

We present a theory of threads, interleaving of threads, and interaction between threads and services with features of molecular dynamics, a model of computation that bears on computations in which dynamic data structures are involved. Threads can interact ... Keywords: Molecular dynamics, Projective limit model, Restriction, Thread algebra, Thread calculus

J. A. Bergstra; C. A. Middelburg

2010-07-01T23:59:59.000Z

370

Classification with dynamic reducts and belief functions  

Science Conference Proceedings (OSTI)

In this paper, we propose two approaches of classification namely, Dynamic Belief Rough Set Classifier (D-BRSC) and Dynamic Belief Rough Set Classifier based on Generalization Distribution Table (D-BRSC-GDT). Both the classifiers are induced from uncertain ... Keywords: belief function theory, classification, dynamic reduct, generalization distribution table, rough sets, uncertainty

Salsabil Trabelsi; Zied Elouedi; Pawan Lingras

2011-01-01T23:59:59.000Z

371

Dynamical instability of collapsing radiating fluid  

SciTech Connect

We take the collapsing radiative fluid to investigate the dynamical instability with cylindrical symmetry. We match the interior and exterior cylindrical geometries. Dynamical instability is explored at radiative and non-radiative perturbations. We conclude that the dynamical instability of the collapsing cylinder depends on the critical value {gamma} < 1 for both radiative and nonradiative perturbations.

Sharif, M., E-mail: msharif.math@pu.edu.pk; Azam, M., E-mail: azammath@gmail.com [University of the Punjab, Department of Mathematics (Pakistan)

2013-06-15T23:59:59.000Z

372

Unwinding relaxation dynamics of polymers  

E-Print Network (OSTI)

The relaxation dynamics of a polymer wound around a fixed obstacle constitutes a fundamental instance of polymer with twist and torque and it is of relevance also for DNA denaturation dynamics. We investigate it by simulations and Langevin equation analysis. The latter predicts a relaxation time scaling as a power of the polymer length times a logarithmic correction related to the equilibrium fluctuations of the winding angle. The numerical data support this result and show that at short times the winding angle decreases as a power-law. This is also in agreement with the Langevin equation provided a winding-dependent friction is used, suggesting that such reduced description of the system captures the basic features of the problem.

Jean-Charles Walter; Marco Baiesi; Gerard Barkema; Enrico Carlon

2013-01-13T23:59:59.000Z

373

Dynamic load balancing of applications  

DOE Patents (OSTI)

An application-level method for dynamically maintaining global load balance on a parallel computer, particularly on massively parallel MIMD computers. Global load balancing is achieved by overlapping neighborhoods of processors, where each neighborhood performs local load balancing. The method supports a large class of finite element and finite difference based applications and provides an automatic element management system to which applications are easily integrated.

Wheat, Stephen R. (Albuquerque, NM)

1997-01-01T23:59:59.000Z

374

Dynamic load balancing of applications  

DOE Patents (OSTI)

An application-level method for dynamically maintaining global load balance on a parallel computer, particularly on massively parallel MIMD computers is disclosed. Global load balancing is achieved by overlapping neighborhoods of processors, where each neighborhood performs local load balancing. The method supports a large class of finite element and finite difference based applications and provides an automatic element management system to which applications are easily integrated. 13 figs.

Wheat, S.R.

1997-05-13T23:59:59.000Z

375

Limit Cycle and Conserved Dynamics  

E-Print Network (OSTI)

We demonstrate that a potential coexists with limit cycle. Here the potential determines the final distribution of population. Our demonstration consists of three steps: We first show the existence of limit from a typical physical sciences setting: the potential is a type of Mexican hat type, with the strength of a magnetic field scale with the strength the potential gradient near the limit cycle, and the friction goes to zero faster than the potential near the limit cycle. Hence the dynamics at the limit cycle is conserved. The diffusion matrix is nevertheless finite at the limit cycle. Secondly, we construct the potential in the dynamics with limit cycle in a typical dynamical systems setting. Thirdly, we argue that such a construction can be carried out in a more general situation based on a method discovered by one of us. This method of dealing with stochastic differential equation is in general different from both Ito and Stratonovich calculus. Our result may be useful in many related applications, such as in the discussion of metastability of limit cycle and in the construction of Hopfield potential in the neural network computation.

X. -M. Zhu; L. Yin; P. Ao

2004-12-21T23:59:59.000Z

376

Turbo Dynamics | Open Energy Information  

Open Energy Info (EERE)

Turbo Dynamics Turbo Dynamics Jump to: navigation, search Name Turbo Dynamics Address 3235 River rd. Place Toledo, Ohio Zip 43614 Sector Biomass, Buildings, Efficiency, Renewable Energy, Services, Solar Product Agriculture; Consulting;Energy audits/weatherization; Engineering/architectural/design;Installation; Maintenance and repair;Manufacturing; Research and development;Retail product sales and distribution;Trainining and education Phone number 419-382-7287 Website http://www.turbodradial.com Coordinates 41.607247°, -83.591719° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":41.607247,"lon":-83.591719,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

377

Dynamical 3-Space: Emergent Gravity  

E-Print Network (OSTI)

The laws of gravitation devised by Newton, and by Hilbert and Einstein, have failed many experimental and observational tests, namely the bore hole g anomaly, flat rotation curves for spiral galaxies, supermassive black hole mass spectrum, uniformly expanding universe, cosmic filaments, laboratory G measurements, galactic EM bending, precocious galaxy formation,.. The response has been the introduction of the new epicycles: ``dark matter", ``dark energy", and others. To understand gravity we must restart with the experimental discoveries by Galileo, and following a heuristic argument we are led to a uniquely determined theory of a dynamical 3-space. That 3-space exists has been missed from the beginning of physics, although it was 1st directly detected by Michelson and Morley in 1887. Uniquely generalising the quantum theory to include this dynamical 3-space we deduce the response of quantum matter and show that it results in a new account of gravity, and explains the above anomalies and others. The dynamical theory for this 3-space involves G, which determines the dissipation rate of space by matter, and alpha, which experiments and observation reveal to be the fine structure constant. For the 1st time we have a comprehensive account of space and matter and their interaction - gravity.

Reginald T Cahill

2011-02-16T23:59:59.000Z

378

Earth materials and earth dynamics  

Science Conference Proceedings (OSTI)

In the project ''Earth Materials and Earth Dynamics'' we linked fundamental and exploratory, experimental, theoretical, and computational research programs to shed light on the current and past states of the dynamic Earth. Our objective was to combine different geological, geochemical, geophysical, and materials science analyses with numerical techniques to illuminate active processes in the Earth. These processes include fluid-rock interactions that form and modify the lithosphere, non-linear wave attenuations in rocks that drive plate tectonics and perturb the earth's surface, dynamic recrystallization of olivine that deforms the upper mantle, development of texture in high-pressure olivine polymorphs that create anisotropic velocity regions in the convecting upper mantle and transition zone, and the intense chemical reactions between the mantle and core. We measured physical properties such as texture and nonlinear elasticity, equation of states at simultaneous pressures and temperatures, magnetic spins and bonding, chemical permeability, and thermal-chemical feedback to better characterize earth materials. We artificially generated seismic waves, numerically modeled fluid flow and transport in rock systems and modified polycrystal plasticity theory to interpret measured physical properties and integrate them into our understanding of the Earth. This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL).

Bennett, K; Shankland, T. [and others

2000-11-01T23:59:59.000Z

379

Dynamical aspects of isotopic scaling  

E-Print Network (OSTI)

Investigation of the effect of the dynamical stage of heavy-ion collisions indicates that the increasing width of the initial isospin distributions is reflected by a significant modification of the isoscaling slope for the final isotopic distributions after de-excitation. For narrow initial distributions, the isoscaling slope assumes the limiting value of the two individual initial nuclei while for wide initial isotopic distributions the slope for hot fragments approaches the initial value. The isoscaling slopes for final cold fragments increase due to secondary emissions. The experimentally observed evolution of the isoscaling parameter in multifragmentation of hot quasiprojectiles at E$_{inc}$=50 AMeV, fragmentation of $^{86}$Kr projectiles at E$_{inc}$=25 AMeV and multifragmentation of target spectators at relativistic energies was reproduced by a simulation with the dynamical stage described using the appropriate model (deep inelastic transfer and incomplete fusion at the Fermi energy domain and spectator-participant model at relativistic energies) and the de-excitation stage described with the statistical multifragmentation model. In all cases the isoscaling behavior was reproduced by a proper description of the dynamical stage and no unambiguous signals of the decrease of the symmetry energy coefficient were observed.

M. Veselsky

2006-07-17T23:59:59.000Z

380

Spectrum and Reactivity of the Solvated Electron in the Ionic...  

NLE Websites -- All DOE Office Websites (Extended Search)

F. Wishart and Pedatsur Neta J. Phys. Chem. B 107, 7261-7267 (2003). Find paper at ACS Publications or use ACS Articles on Request Abstract: Fast pulse radiolysis transient...

Note: This page contains sample records for the topic "ultrafast solvation dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Drag reduction and solvation in polymer solutions Witold Brostow*1  

E-Print Network (OSTI)

with low MDF for: oil well operations; crude oil trans- port; fire fighting; high sewer throughput in a variety of applications1, 2) : oil well operations,crude oil transport, fire fighting,increasing sewer, none of them generally accepted. One of us developed a model of the DR mechanism already in 19835

North Texas, University of

382

Free Energy of Solvation in the Energetic Perspective  

Science Conference Proceedings (OSTI)

The theory of solutions in the energy representation is reformulated in the form of density?functional theory. The Kirkwood charging formula is provided in the energy representation and the density?functional defined over the energy distribution function is introduced through the Legendre transform. The general property of the density functional is then pointed out

Nobuyuki Matubayasi

2007-01-01T23:59:59.000Z

383

Hydration, Solvation and Hydrolysis of Multicharged Metal Ions  

E-Print Network (OSTI)

with than uranium, neptunium and plutonium. 2 The behavior of thorium(IV) in aqueous solution can serve be used in the 232 Th- 233 U cycle which produces much less plutonium and minor actinoids (neptunium solution was stirred #12;32 on a magnetic stirrer for about five hours at 40 C. Ascorbic acid was added

384

Solvation characteristics of a model water-soluble polymer  

Science Conference Proceedings (OSTI)

... in mixtures of d-water (deuterated water) and d-alco- hols (deuterated ... The identification of any commercial product or trade name does not imply ...

2011-02-28T23:59:59.000Z

385

Scalability of Dynamic Storage Allocation Algorithms  

E-Print Network (OSTI)

Dynamic storage allocation has a significant impact on computer performance. A dynamic storage allocator manages space for objects whose lifetimes are not known by the system at the time of their creation. A good dynamic storage allocator should utilize storage efficiently and satisfy requests in as few instructions as possible. A dynamic storage allocator on a multiprocessor should have the ability to satisfy multiple requests concurrently. This paper examines parallel dynamic storage allocation algorithms and how performancescales with increasing numbers of processors. The highest throughputs and lowest instruction counts are achieved with multiple free list fit I. The best memory utilization is achieved using a best fit system.

Arun Iyengar

1996-01-01T23:59:59.000Z

386

Behavior of Laminate Reactive Materials under Dynamic Loading ...  

Science Conference Proceedings (OSTI)

Presentation Title, Behavior of Laminate Reactive Materials under Dynamic Loading ... Atomistically-Informed Dislocation Dynamics Simulations of High Rate  ...

387

Dynamic Pressure Sensing during Rapid Combustion of Metal ...  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, 2011 TMS Annual Meeting & Exhibition. Symposium , Dynamic Behavior of Materials V. Presentation Title, Dynamic Pressure ...

388

Beamline 6.0.2  

NLE Websites -- All DOE Office Websites (Extended Search)

2 Beamline 6.0.2 Print Tuesday, 20 October 2009 08:40 UltrafastFemtosecond Dynamics Soft X Ray Scientific disciplines: Chemical dynamics, materials science, surfaces, interfaces...

389

Dynamic reduction, Version 1. 0  

SciTech Connect

This report describes the theoretical background of the EPRI Dynamic Reduction DYNRED V 1.0. EPRI initiated research under project RP763 to develop the original reduction program DYNEQU. This program was the first to be based on the concept of aggregating of coherent groups of synchronous generators into a single equivalent generator model. While technically advanced, DYNEQU proved difficult to use. Since then, the stability problems encountered in power system planning and operations have changed. The emphasis on first swing transient stability has been replaced by emphasis on inter-area oscillations and voltage stability. The method of identification of coherent generators used in DYNEQU is based on the comparison of rotor angle swings, in a linearized system model, following a fault. It has been shown that this method of coherency identification is good for first swing stability. For inter-area oscillation studies, this method of generator aggregation is less accurate. Far better, are identification methods based on the structure of the power system. Because of these changes in the requirements for reduced order power system models, a new dynamic reduction program (DYNRED) has been developed under EPRI project RP2447-1. It is coherency based, as is DYNEQU, but it has structurally based coherency identification methods in addition to the method used in DYNEQU. This report describes the techniques used in DYNRED, that is: Coherency Identification; Network Reduction; Method of Aggregation, Generator Aggregation, Excitation Aggregation, Primemover/Governor Aggregation. An example of the application of DYNRED to the reduction of a large interconnected power system model is also presented. DYNRED uses the special modeling and network solution techniques developed to enable systems having up to 12,000 bus to be studied. Dynamic data is completely compatible between MASS, PEALS, and the EPRI Extended Transient Midterm Stability Program (ETMSP).

Rogers, G.J.; Wong, D.Y.; Ottevangers, J.; Wang, L. (Ontario Hydro, Toronto, ON (Canada))

1993-04-01T23:59:59.000Z

390

Dynamic Safety Systems (DSS) Technology  

Science Conference Proceedings (OSTI)

This report considers several aspects of Dynamic Safety System (DSS) technology and its use in United States (U.S.) light-water reactor (LWR) safety systems. The topics include: the capability of DSS technology to function in an LWR protection system, the feasibility of licensing DSS technology under Code of Federal Regulations 10 CFR 50.59 for use in a reactor protection system (RPS), and the possibility of extending the automatic self-testing regime to include the front-end neutron sensors that feed si...

1998-05-27T23:59:59.000Z

391

From Fundamentals to Nanoscale Dynamics  

Science Conference Proceedings (OSTI)

This text book gives a comprehensive account of magnetism, one of the oldest yet most vibrant fields of physics. It spans the historical development, the physical foundations and the continuing research underlying the subject. The book covers both the classical and quantum mechanical aspects of magnetism and novel experimental techniques. Perhaps uniquely, it discusses spin transport and magnetization dynamics phenomena associated with atomically and spin engineered nano-structures against the backdrop of spintronics and magnetic storage and memory applications. The book is for students, and serves as a reference for scientists in academia and research laboratories.

Stohr, J.; Siegmann, H.C.

2007-08-08T23:59:59.000Z

392

System D: Dependent Dynamic Dictionaries  

E-Print Network (OSTI)

We present System D, a novel dependent refinement type system that intermingles (semantic) logical refinement predicates and (syntactic) types in order to statically type dictionaries. Specifically, System D shows how McCarthy's theory of arrays can be used to precisely describe dictionary bindings, and uninterpreted predicate symbols can be used to embed classical type constructors (e.g. type variables, arrows, collections) into a decidable refinement logic. As a result, System D decomposes subtyping into a combination of SMT queries and classical syntactic subtyping, thereby enabling, for the first time, static type checking for programs that use dynamic dictionaries with polymorphic, higher-order functions.

Chugh, Ravi; Jhala, Ranjit

2011-01-01T23:59:59.000Z

393

Dynamical polarization in pionic atoms  

SciTech Connect

Dynamical nuclear polarization occurs in pionic atoms when a nuclear excitation of appropriate multipolarity is nearly degenerate with de-excitation of a pion atomic level. This phenomenon has been studied in several nuclei, one goal being to test the pion optical potential for pion atomic states normally ''hidden'' because of pion absorption. We find that, in addition to Coulomb mixing of the atomic and nuclear levels, strong interaction mixing and nuclear excitations above the lowest collective quadrupole mode are important for understanding the experimental results. All cases except /sup 110/Pd can then be understood. For /sup 110/Pd, additional nuclear structure information is needed to determine whether or not the conventional pion optical potential will suffice again. We discuss the sensitivity of dynamical polarization measurements to the parameters of the optical potential and to various aspects of nuclear structure. In particular, we find that pionic /sup 150/Sm provides a test of the interacting boson model and that the difference in neutron and proton radii predicted by Hartree-Fock calculations affects the mixing appreciably.

Dubach, J.F.; Moniz, E.J.; Nixon, G.D.

1979-08-01T23:59:59.000Z

394

Radiation in molecular dynamic simulations  

DOE Green Energy (OSTI)

Hot dense radiative (HDR) plasmas common to Inertial Confinement Fusion (ICF) and stellar interiors have high temperature (a few hundred eV to tens of keV), high density (tens to hundreds of g/cc) and high pressure (hundreds of Megabars to thousands of Gigabars). Typically, such plasmas undergo collisional, radiative, atomic and possibly thermonuclear processes. In order to describe HDR plasmas, computational physicists in ICF and astrophysics use atomic-scale microphysical models implemented in various simulation codes. Experimental validation of the models used to describe HDR plasmas are difficult to perform. Direct Numerical Simulation (DNS) of the many-body interactions of plasmas is a promising approach to model validation but, previous work either relies on the collisionless approximation or ignores radiation. We present a new numerical simulation technique to address a currently unsolved problem: the extension of molecular dynamics to collisional plasmas including emission and absorption of radiation. The new technique passes a key test: it relaxes to a blackbody spectrum for a plasma in local thermodynamic equilibrium. This new tool also provides a method for assessing the accuracy of energy and momentum exchange models in hot dense plasmas. As an example, we simulate the evolution of non-equilibrium electron, ion, and radiation temperatures for a hydrogen plasma using the new molecular dynamics simulation capability.

Glosli, J; Graziani, F; More, R; Murillo, M; Streitz, F; Surh, M

2008-10-13T23:59:59.000Z

395

Dynamical symmetry breaking in geometrodynamics  

E-Print Network (OSTI)

We are going to analyze through a first order perturbative formulation the local loss of symmetry when a source of electromagnetic and gravitational field interacts with an agent that perturbes the original geometry associated to the source. As the symmetry in Abelian or even non-Abelian field structures in four dimensional Lorentzian spacetimes is displayed through the existence of local planes of symmetry that we previously called blades one and two, the loss of symmetry will be manifested by the tilting of these planes under the influence of the external agent. In this strict sense the original local symmetry will be lost. But we will prove that the new blades at the same point will correspond after the tilting generated by perturbation to a new symmetry. The point of this note is to prove that the geometrical manifestation of local gauge symmetries is dynamic. The local original symmetries will be lost, nonetheless new symmetries will arise. There is a dynamic evolution of local symmetries.

Alcides Garat

2013-06-03T23:59:59.000Z

396

Reaction Dynamics with Exotic Beams  

E-Print Network (OSTI)

We review the new possibilities offered by the reaction dynamics of asymmetric heavy ion collisions, using stable and unstable beams. We show that it represents a rather unique tool to probe regions of highly Asymmetric Nuclear Matter ($ANM$) in compressed as well as dilute phases, and to test the in-medium isovector interaction for high momentum nucleons. The focus is on a detailed study of the symmetry term of the nuclear Equation of State ($EOS$) in regions far away from saturation conditions but always under laboratory controlled conditions. Thermodynamic properties of $ANM$ are surveyed starting from nonrelativistic and relativistic effective interactions. In the relativistic case the role of the isovector scalar $\\delta$-meson is stressed. The qualitative new features of the liquid-gas phase transition, "diffusive" instability and isospin distillation, are discussed. The results of ab-initio simulations of n-rich, n-poor, heavy ion collisions, using stochastic isospin dependent transport equations, are analysed as a function of beam energy and centrality. The isospin dynamics plays an important role in all steps of the reaction, from prompt nucleon emissions to the final fragments. The isospin diffusion is also of large interest, due to the interplay of asymmetry and density gradients. In relativistic collisions, the possibility of a direct study of the covariant structure of the effective nucleon interaction is shown. Results are discussed for particle production, collective flows and iso-transparency. Perspectives of further developments of the field, in theory as well as in experiment, are presented.

V. Baran; M. Colonna; V. Greco; M. Di Toro

2004-12-15T23:59:59.000Z

397

GAS-PHASE MOLECULAR DYNAMICS: VIBRATIONAL DYNAMICS OF POLYATOMIC MOLECULES  

SciTech Connect

The goal of this research is the understanding of elementary chemical and physical processes important in the combustion of fossil fuels. Interest centers on reactions and properties of short-lived chemical intermediates. High-resolution, high-sensitivity, laser absorption methods are augmented by high-temperature, flow-tube reaction kinetics studies with mass-spectrometric sampling. These experiments provide information on the energy levels, structures and reactivity of molecular free radical species and, in turn, provide new tools for the study of energy flow and chemical bond cleavage in radicals involved in chemical systems. The experimental work is supported by theoretical studies using time-dependent quantum wavepacket calculations, which provide insight into energy flow among the vibrational modes of polyatomic molecules and interference effects in multiple-surface dynamics.

MUCKERMAN,J.T.

1999-06-09T23:59:59.000Z

398

Gas-Phase Molecular Dynamics: Vibrational Dynamics of Polyatomic Molecules  

SciTech Connect

The goal of this research is the understanding of elementary chemical and physical processes important in the combustion of fossil fuels. Interest centers on reactions and properties of short-lived chemical intermediates. High-resolution, high-sensitivity, laser absorption methods are augmented by high- temperature, flow-tube reaction kinetics studies with mass-spectrometic sampling. These experiments provide information on the energy levels, structures and reactivity of molecular free radical species and in turn, provide new tools for the study of energy flow and chemical bond cleavage in the radicals involved in chemical systems. The experimental work is supported by theoretical studies using time-dependent quantum wavepacket calculations, which provide insight into energy flow among the vibrational modes of polyatomic molecules and interference effects in multiple-surface dynamics.

Muckerman, J.T.

1999-05-21T23:59:59.000Z

399

Dynamic Evolution for Risk-Neutral Densities  

E-Print Network (OSTI)

We solved the scaled formulation for problems (7) and (10) and obtained the dynamic evolution for the densities (see Figure 1). For this data set, we.

400

Microstructure and Dynamic Deformation Behavior of Nanometer ...  

Science Conference Proceedings (OSTI)

Dynamic deformation behavior at strain rates of around 103 s-1 was performed using split Hopkinson bar technique. The results show that, the flow stress ...

Note: This page contains sample records for the topic "ultrafast solvation dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Understanding the Dynamic Indentation Behaviour of Metallic ...  

Science Conference Proceedings (OSTI)

In contrast, the dynamic indentation hardness behaviour of metallic materials, characterized by ultra-high strain rate plastic deformation under adiabatic ...

402

A Dynamic Platform for Runtime Adaptation  

E-Print Network (OSTI)

We present a middleware platform for assembling pervasive applications that demand fault-tolerance and adaptivity in distributed, dynamic environments. Unlike typical adaptive middleware approaches, in which sophisticated ...

Pham, Hubert

403

Available Technologies: Dynamic Solar Glare Blocking System  

Dynamic Solar Glare Blocking System IB-2415. APPLICATIONS OF TECHNOLOGY: ... U.S. DEPARTMENT OF ENERGY • OFFICE OF SCIENCE • UNIVERSITY OF CALIFORNIA.

404

Continuous Dynamic Constrained Optimisation – The Challenges  

E-Print Network (OSTI)

May 24, 2012 ... cs.bham.ac.uk). Abstract: Many real-world dynamic problems have constraints, and in certain cases not only the objective function changes ...

405

EMSL: Science: Biological Interactions and Dynamics  

NLE Websites -- All DOE Office Websites (Extended Search)

Biological Interactions and Dynamics Cryo-transmission electron microscope image of Shewanella oneidensis MR-1. Understanding and optimizing the response of organisms and...

406

On the Dynamic Stability of Electricity Markets  

E-Print Network (OSTI)

Electricity market models have become an indispensable tool for analyzing and pre- dicting the impact of diverse dynamic drivers (e.g., weather, load, fuel prices  ...

407

Mathematical modeling of irreversible dynamic deformation, micro...  

National Nuclear Security Administration (NNSA)

proceed in deformable solids under intensive dynamic loading, consist of mechanical, thermal and structural ones, which correlate themselves. The structural processes involve the...

408

Optimal control of leukemic cell population dynamics  

E-Print Network (OSTI)

Sep 5, 2013 ... This issue can be formulated as an optimal control problem. The dynamics of leukemic cell populations in culture is given by age-structured ...

409

Convergence and Perturbation Resilience of Dynamic String ...  

E-Print Network (OSTI)

Jun 1, 2012 ... Optimization Online. Convergence and Perturbation Resilience of Dynamic String-Averaging Projection Methods. Yair Censor(yair ***at*** ...

410

The Dynamics of Moonlighting in Pakistan  

E-Print Network (OSTI)

of Sciences and Technology, Pakistan January 2011 10945 LeDynamics of Moonlighting in Pakistan Asma Hyder and Ather18 March, 2010 Islamabad, Pakistan Institute of Development

Hyder, Asma; Ahmed, Ather Maqsood

2011-01-01T23:59:59.000Z

411

NREL: Continuum Magazine - Sustainability through Dynamic Energy...  

NLE Websites -- All DOE Office Websites (Extended Search)

Magazine - Clean Energy Innovation at NREL Search Home About Archives Subscribe Sustainability through Dynamic Energy Management Issue 4 Print Version Share this resource...

412

Molecular Dynamics of Martenstic Phase Transitions  

Science Conference Proceedings (OSTI)

Presentation Title, Kinetics of martensitic phase transformation: Molecular Dynamics of Martenstic ... A Comparison of Coulombic and Plastic Shear Faults in Ice.

413

MML Leads Discussion of Dynamic Fracture Testing  

Science Conference Proceedings (OSTI)

Dynamic Fracture in Steel. ... More recently, the pipeline industry has been adopting the CTOA ... fatigue characteristics of new pipeline steels, as these ...

2012-10-15T23:59:59.000Z

414

Quantum relaxation dynamics using Bohmian trajectories  

Science Conference Proceedings (OSTI)

We present a new Bohmian trajectory based treatment of quantum dynamics suitable for dissipative systems. Writing the density matrix in complex-polar form

Jeremy B. Maddox; Eric R. Bittner

2001-01-01T23:59:59.000Z

415

A Recursive Lagrangian Formulation of Manipulator Dynamics  

E-Print Network (OSTI)

An efficient Lagrangian formulation of manipulator dynamics has been developed. The efficiency derives from recurrence relations for the velocities, accelerations, and generalized forces. The number of additions and ...

Hollerbach, John M.

1980-06-01T23:59:59.000Z

416

ORNL DAAC for Biogeochemical Dynamics  

NLE Websites -- All DOE Office Websites (Extended Search)

Home Home Welcome about us image About Us Provides detailed information about the ORNL DAAC. projects image About Data Lists the data products available from the ORNL DAAC. access image Get Data Guides you through the steps needed to acquire the data. tools image Data Tools Some tools to help you work with the data. uso image Help Need assistance? Our staff is happy to help. ORNL DAAC The Oak Ridge National Laboratory Distributed Active Archive Center (ORNL DAAC) for biogeochemical dynamics is one of the National Aeronautics and Space Administration (NASA) Earth Observing System Data and Information System (EOSDIS) data centers managed by the Earth Science Data and Information System (ESDIS) Project. The ORNL DAAC archives data produced by NASA's Terrestrial Ecology Program. The DAAC provides data and information

417

Dynamical failure of Turing patterns  

E-Print Network (OSTI)

The emergence of stable disordered patterns in reactive system on spatially homogenous substrate is studied in the context of vegetation patterns in the semi-arid climatic zone. It is shown that reaction-diffusion systems that allow for Turing instability may exhibit heterogeneous "glassy" steady state, with no characteristic wavelength, if the diffusion rate associated with the "slow" reactant is very small. Upon decreasing the diffusion constant of the slow reactant three phases are identified: strong diffusion yields a stable homogenous phase, intermediate diffusion implies Turing (crystal like) patterns while in the slow diffusion limit the glassy state is the generic stable solution. In this disordered phase the dynamics is of crucial importance, with strong differences between local and global initiation.

Alon Manor; Nadav M. Shnerb

2005-08-08T23:59:59.000Z

418

Quantum dynamics in dual spaces  

Science Conference Proceedings (OSTI)

Quantum mechanics gives us information about spectra of dynamical variables and transition rates including scattering cross sections. They can be exhibited as spectral information in analytically continued spaces and their duals. Quantum mechanics formulated in these generalized spaces is used to study scattering and time evolution. It is shown that the usual asymptotic condition is inadequate to deal with scattering of composite or unstable particles. Scattering theory needs amendment when the interacting system is not isospectral with the free Hamiltonian, and the amendment is formulated. Perturbation theory in generalized spaces is developed and used to study the deletion and augmentation of the spectrum of the Hamiltonian. A complete set of algebraically independent constants for an interacting system is obtained. The question of the breaking of time symmetry is discussed.

Sudarshan, E.C.G.

1993-12-31T23:59:59.000Z

419

Fluid dynamics of bacterial turbulence  

E-Print Network (OSTI)

Self-sustained turbulent structures have been observed in a wide range of living fluids, yet no quantitative theory exists to explain their properties. We report experiments on active turbulence in highly concentrated 3D suspensions of Bacillus subtilis and compare them with a minimal fourth-order vector-field theory for incompressible bacterial dynamics. Velocimetry of bacteria and surrounding fluid, determined by imaging cells and tracking colloidal tracers, yields consistent results for velocity statistics and correlations over two orders of magnitude in kinetic energy, revealing a decrease of fluid memory with increasing swimming activity and linear scaling between energy and enstrophy. The best-fit model parameters allow for quantitative agreement with experimental data.

Jörn Dunkel; Sebastian Heidenreich; Knut Drescher; Henricus H. Wensink; Markus Bär; Raymond E. Goldstein

2013-02-21T23:59:59.000Z

420

Efficiency of the dynamical mechanism  

E-Print Network (OSTI)

The most extreme starbursts occur in galaxy mergers, and it is now acknowledged that dynamical triggering has a primary importance in star formation. This triggering is due partly to the enhanced velocity dispersion provided by gravitational instabilities, such as density waves and bars, but mainly to the radial gas flows they drive, allowing large amounts of gas to condense towards nuclear regions in a small time scale. Numerical simulations with several gas phases, taking into account the feedback to regulate star formation, have explored the various processes, using recipes like the Schmidt law, moderated by the gas instability criterion. May be the most fundamental parameter in starbursts is the availability of gas: this sheds light on the amount of external gas accretion in galaxy evolution. The detailed mechanisms governing gas infall in the inner parts of galaxy disks are discussed.

F. Combes

2004-11-15T23:59:59.000Z

Note: This page contains sample records for the topic "ultrafast solvation dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Shock dynamics of phase diagrams  

E-Print Network (OSTI)

A thermodynamic phase transition denotes a drastic change of state of a physical system due to a continuous change of thermodynamic variables, as for instance pressure and temperature. The classical van der Waals equation of state is the simplest model that predicts the occurrence of a critical point associated with the gas-liquid phase transition. Nevertheless, below the critical temperature, theoretical predictions of the van der Waals theory significantly depart from the observed physical behaviour. We develop a novel approach to classical thermodynamics based on the solution of Maxwell relations for a generalised family of nonlocal entropy functions. This theory provides an exact mathematical description of discontinuities of the order parameter within the phase transition region, it explains the universal form of the equations of state and the occurrence of triple points in terms of the dynamics of nonlinear shock wave fronts.

Antonio Moro

2013-07-29T23:59:59.000Z

422

Reaction Dynamics with Exotic Beams  

E-Print Network (OSTI)

We review the new possibilities offered by the reaction dynamics of asymmetric heavy ion collisions, using stable and unstable beams. We show that it represents a rather unique tool to probe regions of highly Asymmetric Nuclear Matter ($ANM$) in compressed as well as dilute phases, and to test the in-medium isovector interaction for high momentum nucleons. The focus is on a detailed study of the symmetry term of the nuclear Equation of State ($EOS$) in regions far away from saturation conditions but always under laboratory controlled conditions. Thermodynamic properties of $ANM$ are surveyed starting from nonrelativistic and relativistic effective interactions. In the relativistic case the role of the isovector scalar $\\delta$-meson is stressed. The qualitative new features of the liquid-gas phase transition, "diffusive" instability and isospin distillation, are discussed. The results of ab-initio simulations of n-rich, n-poor, heavy ion collisions, using stochastic isospin dependent transport equations, are ...

Baran, V; Greco, V; Di Toro, M

2004-01-01T23:59:59.000Z

423

Microtubule catastrophe from protofilament dynamics  

E-Print Network (OSTI)

The disappearance of the guanosine triphosphate (GTP)-tubulin cap is widely believed to be the forerunner event for the growth-shrinkage transition (`catastrophe') in microtubule filaments in eukaryotic cells. We study a discrete version of a stochastic model of the GTP cap dynamics, originally proposed by Flyvbjerg, Holy and Leibler (Flyvbjerg, Holy and Leibler, Phys. Rev. Lett. 73, 2372, 1994). Our model includes both spontaneous and vectorial hydrolysis, as well as dissociation of a non-hydrolyzed dimer from the filament after incorporation. In the first part of the paper, we apply this model to a single protofilament of a microtubule. A catastrophe transition is defined for each protofilament, similar to the earlier one-dimensional models, the frequency of occurrence of which is then calculated under various conditions, but without explicit assumption of steady state conditions. Using a perturbative approach, we show that the leading asymptotic behavior of the protofilament catastrophe in the limit of large growth velocities is remarkably similar across different models. In the second part of the paper, we extend our analysis to the entire filament by making a conjecture that a minimum number of such transitions are required to occur for the onset of microtubule catastrophe. The frequency of microtubule catastrophe is then determined using numerical simulations, and compared with analytical/semi-analytical estimates made under steady state/quasi-steady state assumptions respectively for the protofilament dynamics. A few relevant experimental results are analyzed in detail, and compared with predictions from the model. Our results indicate that loss of GTP cap in 2-3 protofilaments is necessary to trigger catastrophe in a microtubule.

Jemseena V.; Manoj Gopalakrishnan

2013-08-27T23:59:59.000Z

424

Dynamic Response Analysis of Underground Powerhouse Structures Considering Coupling Effects of Hydraulic Impulse and Dynamic Loads  

Science Conference Proceedings (OSTI)

When accident takes place in hydropower generator units, they transit from normal working condition to accident working condition. During this period, the generator pier structures bear coupling effect of dynamic load from the units and hydraulic impulse ... Keywords: underground powerhouse structure, unit dynamic load, hydraulic impulse, coupling effect, dynamic analysis

Li Xiaoli; Yuan Chaoqing; Li Ke; Li Yujie

2012-05-01T23:59:59.000Z

425

Stability boundary analysis of the dynamic voltage restorer in weak systems with dynamic loads  

Science Conference Proceedings (OSTI)

In this contribution, a stability analysis for a dynamic voltage restorer (DVR) connected to a weak ac system containing a dynamic load is presented using continuation techniques and bifurcation theory. The system dynamics are explored through the continuation ... Keywords: DVR, Floquet multiplier, active filter, continuation techniques, iterative map, point common coupling, power converter, stability regions, switching process

Juan Segundo-Ramírez; Aurelio Medina; Arindam Ghosh; Gerard Ledwich

2012-06-01T23:59:59.000Z

426

Idealized Test Cases for Dynamical Core Experiments  

E-Print Network (OSTI)

Idealized Test Cases for Dynamical Core Experiments Christiane Jablonowski (University of Michigan-13/2006 #12;Motivation · Test cases for 3D dynamical cores on the sphere ­ are hard to find in the literature groups ­ lack standardized & easy-to-use analysis techniques · Idea: Establish a collection of test cases

Jablonowski, Christiane

427

Spin dynamics in (110)-oriented quantum wells  

Science Conference Proceedings (OSTI)

Quantum structures of III-V semiconductors grown on (110)-oriented substrates are promising for spintronic applications because they allow us to engineer and control spin dynamics of electrons. We summarise the theoretical ideas, which are the basis ... Keywords: Quantum wells, Spin dynamics, Spintronics

R. T. Harley; O. Z. Karimov; M. Henini

2006-12-01T23:59:59.000Z

428

Dynamic detection of nuclear reactor core incident  

Science Conference Proceedings (OSTI)

Surveillance, safety and security of evolving systems are a challenge to prevent accident. The dynamic detection of a hypothetical and theoretical blockage incident in the Phenix nuclear reactor is investigated. Such an incident is characterized by abnormal ... Keywords: Contrast, Dynamic detection of perturbations, Evolving system, Fast-neutron reactor, Neighbourhood, Noise

Laurent Hartert; Danielle Nuzillard; Jean-Philippe Jeannot

2013-02-01T23:59:59.000Z

429

NON-LINEAR DYNAMICS IDENTIFICATION USING  

E-Print Network (OSTI)

to be identified and extracted from the data. The above work is applied to a real physical wind turbine data 143 5 Case Study: Identification of Wind Turbine Dynamics Using Gaussian Processes 145 5 Turbine Dynamics 147 5.3.1 About the Data 148 5.3.2 Cleaning Up Raw Data (Phase 1) 152 5.3.3 Nonlinear

Duffy, Ken

430

Carbon and Nitrogen Dynamics in Agricultural Soils  

E-Print Network (OSTI)

Carbon and Nitrogen Dynamics in Agricultural Soils Model Applications at Different Scales in Time Print: SLU Service/Repro, Uppsala 2012 #12;Carbon and Nitrogen Dynamics in Agricultural Soils. Model Applications at Different Scales in Time and Space Abstract An understanding of soil organic carbon (C

431

Dynamic substructure method for elastic fractal structures  

Science Conference Proceedings (OSTI)

We investigate the fractal properties on the distribution of natural frequencies of elastic structures. We use the multi-level-multi-scale dynamic substructure method so that we need only to eliminate a few nodes in advancing a fractal level. We shall ... Keywords: Dynamic condensation, Elastic fractal structures, Frequency power laws, Multi-level-multi-scale

A. Y. T. Leung

2011-02-01T23:59:59.000Z

432

Dynamic Pricing and Learning in Electricity Markets  

Science Conference Proceedings (OSTI)

We analyze the price-formation process in an infinite-horizon oligopoly model where hydroelectric generators engage in dynamic price-based competition. The analysis focuses on the role of "indifference" prices, i.e., prices that equate the gains from ... Keywords: Dynamic auctions, Economics, Games: stochastic, Natural resources: energy, Noncooperative, Restructured electricity markets, Water resources

Alfredo Garcia; Enrique Campos-Nañez; James Reitzes

2005-03-01T23:59:59.000Z

433

Quantifying Dynamic Stability of Genetic Memory Circuits  

Science Conference Proceedings (OSTI)

Bistability/Multistability has been found in many biological systems including genetic memory circuits. Proper characterization of system stability helps to understand biological functions and has potential applications in fields such as synthetic biology. ... Keywords: Dynamic stability, genetic memory, gene circuit, dynamic noise margin.

Yong Zhang; Peng Li; Garng Huang

2012-05-01T23:59:59.000Z

434

Brain dynamics promotes function Carlos Lourenco  

E-Print Network (OSTI)

dynamics? At this point in brain research, we are happy if we can at least provide a partial answer. Key. Natural scientists look for correlations between measured electrical signals and behavior or mental states by considering the so-called dynamical complex- ity as revealed e.g. by the measurement of the brain's electrical

435

Module Allocation for Dynamically Reconfigurable Systems  

Science Conference Proceedings (OSTI)

The synthesis of dynamically reconfigurable systems poses some new challenges for high-level synthesis tools. In this paper, we deal with the task of module allocation as this step has a direct influence on the performance of the dynamically reconfigudreasbiglne. ...

Xue-Jie Zhang; Kam-Wing Ng

2000-05-01T23:59:59.000Z

436

MATHEMATICS Price dynamics in political prediction markets  

E-Print Network (OSTI)

- gate the price dynamics of prediction markets with the goal of developing methods to identify the trulyAPPLIED MATHEMATICS POLITICAL SCIENCES Price dynamics in political prediction markets Saikat Ray City, IA 52242; and d Department Chemical and Biological Engineering, Northwestern University, Evanston

Amaral, Luis A.N.

437

Dynamic field theory and embodied communication  

Science Conference Proceedings (OSTI)

Dynamical Field Theory is a neurally based approach to embodied and situated cognition, in which information is represented in continuous activation fields defined over metric spaces. The temporal evolution of activation patterns under the influence ... Keywords: embodied cognition, modelling, neural dynamics, turn taking

Yulia Sandamirskaya; Gregor Schöner

2006-04-01T23:59:59.000Z

438

Chemical mechanical planarization operation via dynamic programming  

Science Conference Proceedings (OSTI)

In this paper, the impact on non-planarization index by the down force and rotational speed during a SiO"2 or Cu CMP process was investigated. Since the magnitudes of down force and rotational speed have limits, we choose the dynamic programming approach ... Keywords: Chemical mechanical planarization, Copper dishing, Dynamic programming, Non-planarization index, Oxide erosion

Chia-Shui Lin; Yung-Chou Lee

2007-12-01T23:59:59.000Z

439

Dynamic computation migration in DSM systems  

Science Conference Proceedings (OSTI)

We describe dynamic computation migration, the runtime choice between computation and data migration. Dynamic computation migration is useful for concurrent data structures with unpredictable read/write patterns. We implemented it in MCRL, a multithreaded ... Keywords: computation migration, data migration, replication, coherence

Wilson C. Hsieh; M. Frans Kaashoek; William E. Weihl

1996-11-01T23:59:59.000Z

440

Stability issues for dynamic traffic assignment  

Science Conference Proceedings (OSTI)

This paper explores stability issues for operational route guidance control strategies for vehicular traffic networks equipped with advanced information systems, and develops a general procedure for the stability analysis of the associated dynamic traffic ... Keywords: Dynamical systems, Feedback control, Lyapunov methods, Stability analysis

S. Peeta; T. -H. Yang

2003-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "ultrafast solvation dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Information sharing and security in dynamic coalitions  

Science Conference Proceedings (OSTI)

Today, information sharing is critical to almost every institution. There is no more critical need for information sharing than during an international crisis, when international coalitions dynamically form. In the event of a crisis, whether it is humanitarian ... Keywords: access control, distributed systems, dynamic coalitions, information security

Charles E. Phillips, Jr.; T.C. Ting; Steven A. Demurjian

2002-06-01T23:59:59.000Z

442

Power minimization for dynamically reconfigurable FPGA partitioning  

Science Conference Proceedings (OSTI)

Dynamically reconfigurable FPGA (DRFPGA) implements a given circuit system by partitioning it into stages and then executing each stage sequentially. Traditionally, the number of communication buffers is minimized. In this article, we study the partitioning ... Keywords: Dynamically reconfigurable FPGA, power optimization, reconfigurable computing, temporal partitioning

Tzu-Chiang Tai; Yen-Tai Lai

2013-03-01T23:59:59.000Z

443

Dynamic positioning systems: usability and interaction styles  

Science Conference Proceedings (OSTI)

This paper describes the first steps of a research project directed towards human computer interaction (HCI) within the maritime environment and on maritime equipment. The focus is at this stage mainly on interaction with Dynamic Positioning Systems ... Keywords: bi-manual interaction, dynamic positioning, gestures, graphical user interface, maritime environment, multi-touch, safety critical situations

Frøy Birte Bjørneseth; Mark D. Dunlop; Jann Peter Strand

2008-10-01T23:59:59.000Z

444

Generativity and dynamic opacity for abstract types  

Science Conference Proceedings (OSTI)

The standard formalism for explaining abstract types is existential quantification. While it provides a sufficient model for type abstraction in entirely statically typed languages, it proves to be too weak for languages enriched with forms of dynamic ... Keywords: abstract types, dynamic typing, encapsulation, existential types, generativity, opacity

Andreas Rossberg

2003-08-01T23:59:59.000Z

445

An Infrastructure for Adaptive Dynamic Optimization  

E-Print Network (OSTI)

and can be used for instru- mentation, profiling, dynamic translation, etc. To demonstrate the usefulnessRIO performance is 12%. 1 Introduction The power and reach of static analysis is diminishing for modern software, which heavily utilizes dynamic class loading, shared libraries, and runtime binding. Not only

Amarasinghe, Saman

446

Cytoskeleton dynamics: Fluctuations within the network  

Science Conference Proceedings (OSTI)

Out-of-equilibrium systems, such as the dynamics of a living cytoskeleton (CSK), are inherently noisy with fluctuations arising from the stochastic nature of the underlying biochemical and molecular events. Recently, such fluctuations within the cell were characterized by observing spontaneous nano-scale motions of an RGD-coated microbead bound to the cell surface [Bursac et al., Nat. Mater. 4 (2005) 557-561]. While these reported anomalous bead motions represent a molecular level reorganization (remodeling) of microstructures in contact with the bead, a precise nature of these cytoskeletal constituents and forces that drive their remodeling dynamics are largely unclear. Here, we focused upon spontaneous motions of an RGD-coated bead and, in particular, assessed to what extent these motions are attributable to (i) bulk cell movement (cell crawling), (ii) dynamics of focal adhesions, (iii) dynamics of lipid membrane, and/or (iv) dynamics of the underlying actin CSK driven by myosin motors.

Bursac, Predrag [Molecular and Integrative Physiological Sciences, Department of Environmental Health, Harvard School of Public Health, Boston, MA 02115 (United States); Sports Medicine Group, Regeneration Technologies Inc., Alachua, FL 32616 (United States); Fabry, Ben [Department of Physics, Erlangen University, Erlangen (Germany); Trepat, Xavier [Molecular and Integrative Physiological Sciences, Department of Environmental Health, Harvard School of Public Health, Boston, MA 02115 (United States); Lenormand, Guillaume [Molecular and Integrative Physiological Sciences, Department of Environmental Health, Harvard School of Public Health, Boston, MA 02115 (United States); Butler, James P. [Molecular and Integrative Physiological Sciences, Department of Environmental Health, Harvard School of Public Health, Boston, MA 02115 (United States); Wang, Ning [Molecular and Integrative Physiological Sciences, Department of Environmental Health, Harvard School of Public Health, Boston, MA 02115 (United States); Fredberg, Jeffrey J. [Molecular and Integrative Physiological Sciences, Department of Environmental Health, Harvard School of Public Health, Boston, MA 02115 (United States); An, Steven S. [Molecular and Integrative Physiological Sciences, Department of Environmental Health, Harvard School of Public Health, Boston, MA 02115 (United States); Division of Physiology, Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205 (United States); E-mail: san@jhsph.edu

2007-04-06T23:59:59.000Z

447

Dynamic Whitelist Generation for Automated Response  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Methodology Methodology Results Dynamic Whitelist Generation for Automated Response Chris Strasburg, Josh Adams Ames Laboratory, US DOE cstras@ameslab.gov, jadams@ameslab.gov The Ames Laboratory, US DOE 1 Dynamic Whitelist Generation for Automated Response Introduction Methodology Results Outline 1 Introduction About Ames Laboratory Motivation 2 Methodology Data Classifiers Experiments 3 Results The Ames Laboratory, US DOE 2 Dynamic Whitelist Generation for Automated Response Introduction Methodology Results About Ames Laboratory Motivation Ames Physical Environment The Ames Laboratory, US DOE 3 Dynamic Whitelist Generation for Automated Response Introduction Methodology Results About Ames Laboratory Motivation Ames Network Environment The Ames Laboratory, US DOE 4 Dynamic Whitelist Generation for Automated Response Introduction Methodology Results About Ames

448

Dynamism in the solar core  

E-Print Network (OSTI)

Recent results of a mixed shell model heated asymmetrically by transient increases in nuclear burning indicate the transient generation of small hot spots inside the Sun somewhere between 0.1 and 0.2 solar radii. These hot bubbles are followed by a nonlinear differential equation system with finite amplitude non-homologous perturbations which is solved in a solar model. Our results show the possibility of a direct connection between the dynamic phenomena of the solar core and the atmospheric activity. Namely, an initial heating about DQ_0 ~ 10^{31}-10^{37} ergs can be enough for a bubble to reach the outer convective zone. Our calculations show that a hot bubble can arrive into subphotospheric regions with DQ_final ~ 10^{28} - 10^{34} ergs with a high speed, up to 10 km s-1, approaching the local sound speed. We point out that the developing sonic boom transforms the shock front into accelerated particle beam injected upwards into the top of loop carried out by the hot bubble above its forefront traveling fro...

Grandpierre, Attila

2010-01-01T23:59:59.000Z

449

The Dynamics of Price Discovery ?  

E-Print Network (OSTI)

When arbitrage related prices share the same underlying asset, there are multiple channels to incorporate new information on the fundamental value of the asset. In this paper, we present an empirical microstructure model to characterize each channel’s price discovery speed. We identify the information sources of price adjustments to separate price discovery from the market responses to liquidity shocks. We assess market efficiency of price discovery visually, by the time paths of price convergence toward the new fundamental value, and numerically, by the magnitude of pricing errors during the price discovery process. We also use our price discovery model to illustrate the structural determinants of two often used price discovery measures: the information share and component share. We show that two measures are static and unable to reveal the underlying price discovery dynamics between markets. Applying our new measures to quotes from spot foreign exchange rates, we find that substantial price discovery of the yen/euro exchange rate occurs through the US dollar. The dollar’s price discovery contribution is positively related to the relative liquidity of the dollar markets versus the cross rate market, and reaches a minimum during the European business hours.

Bingcheng Yan; Eric Zivot

2004-01-01T23:59:59.000Z

450

Dynamic deformation of advanced materials  

SciTech Connect

This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The objective of this project was to provide high-quality experimental measurements on composite materials and to develop computational models describing the deformation response of these materials. Specifically, the authors studied the influence of strain rate and shock loading on the deformation and fracture response of a 6061-T6 Al-50 vol.% Al{sub 2}O{sub 3} continuous fiber-reinforced composite as a function of composite orientation. The stress-strain response was found to vary substantially as a function of loading orientation with the quasi-static yield changing from nominally 300 MPa transverse to the fibers to {approximately}1,000 MPa parallel to the fibers. Transverse VISAR wave profile and spall measurements revealed a small, well-defined elastic precursor followed by a reasonably sharp shock rise. The failure response of the composite transverse to the fibers, under both uniaxial stress (quasi-static and dynamic) and uniaxial strain loading, displays a protracted but substantial load drop after yield followed by continued degradation in load carrying capacity. Lack of ideal parallel fiber construction leads to systematic bending failure of the alumina fibers through the sample under uniaxial stress and slow spallation kinetics as various fibers fail and pull out of the matrix across the spall plane.

Gray, G.T. III; Johnson, J.N.; Hixson, R.S.; Albert, D.E.; Song, S.

1996-04-01T23:59:59.000Z

451

Metadata driven memory optimizations in dynamic binary translator  

Science Conference Proceedings (OSTI)

A dynamic binary translator offers solutions for translating and running source architecture binaries on target architecture at runtime. Regardless of its growing popularity, practical dynamic binary translators usually suffer from the limited optimizations ... Keywords: dynamic binary translator, memory optimizations, metadata

Chaohao Xu; Jianhui Li; Tao Bao; Yun Wang; Bo Huang

2007-06-01T23:59:59.000Z

452

Molecular Dynamics Study of Krypton Isotopes Physisorbed on Graphite  

E-Print Network (OSTI)

Equations of Motion in Molecular Dynamics” Lecture Notes,OF CALIFORNIA RIVERSIDE Molecular Dynamics Study of Krypton2.5 Choice of Time step in Molecular Dynamics 2.6 Desorption

Bader, Karson

2012-01-01T23:59:59.000Z

453

Proceedings of the 2007 symposium on Dynamic languages  

Science Conference Proceedings (OSTI)

The Dynamic Languages Symposium (DLS) is a forum for discussion of dynamic languages, their implementation and application. While mature dynamic languages including Smalltalk, Lisp, Scheme, Self, and Prolog continue to grow and inspire new converts, ...

Pascal Costanza; Robert Hirschfeld

2007-10-01T23:59:59.000Z

454

A dynamic adjustment strategy for file transformation in data grids  

Science Conference Proceedings (OSTI)

In this paper, we propose a dynamic file transfer scheme with coallocation architecture, called Dynamic Adjustment Strategy, a dynamic file transfer scheme with co-allocation architecture that reduce the file transfer times and improves the performance ...

Chao-Tung Yang; Shih-Yu Wang; Chun-Pin Fu

2007-09-01T23:59:59.000Z

455

Dynamic stall of small wind systems  

SciTech Connect

Aerospace Systems, Inc. (ASI) conducted a study of dynamic stall in order to define its influence on the airfoil force and moment coefficients so that these effects can be included in the calculation of small wind energy conversion system (SWECS) loads and response. The effort includes a review of past work to determine its applicability to SWECS requirements, a definition of a dynamic stall theory for use in SWECS design, and computer implementation of the theory in SWECS loads and dynamic response analyses. Sample calculations are made for representative vertical-axis (VAWT) and horizontal-axis (HAWT) wind turbines. The basic results for the fixed-pitch HAWT show that dynamic stall effects may increase normal loads and moments by about ten percent. For the cyclic pitch VAWT, the peak normal load may be slightly underestimated but the peak moment may be significantly underestimated. The consequences of dynamic stall may be a change in performance with resultant mismatch of selected components or a reduction in the fatigue life of the SWECS structure. Semiempirical methods are used for the practical estimation of the forces and moments on oscillating airfoils or airfoils in an oscillating airstream. The dynamic stall method presented in this report is applicable primarily to large amplitude oscillations of the airfoil. Fully-developed dynamic stall is presumed and, therefore, the method may not be adequate for predicting aerodynamic loads and moments for incipient or light stall.

Noll, R.B.; Ham, N.D.

1983-02-01T23:59:59.000Z

456

TRACKING CODE DEVELOPMENT FOR BEAM DYNAMICS OPTIMIZATION  

SciTech Connect

Dynamic aperture (DA) optimization with direct particle tracking is a straight forward approach when the computing power is permitted. It can have various realistic errors included and is more close than theoretical estimations. In this approach, a fast and parallel tracking code could be very helpful. In this presentation, we describe an implementation of storage ring particle tracking code TESLA for beam dynamics optimization. It supports MPI based parallel computing and is robust as DA calculation engine. This code has been used in the NSLS-II dynamics optimizations and obtained promising performance.

Yang, L.

2011-03-28T23:59:59.000Z

457

Regional Dynamics Model (REDYN) | Open Energy Information  

Open Energy Info (EERE)

Regional Dynamics Model (REDYN) Regional Dynamics Model (REDYN) Jump to: navigation, search Tool Summary Name: REDYN Agency/Company /Organization: Regional Dynamics Inc. Sector: Energy Phase: Determine Baseline, "Evaluate Options and Determine Feasibility" is not in the list of possible values (Bring the Right People Together, Create a Vision, Determine Baseline, Evaluate Options, Develop Goals, Prepare a Plan, Get Feedback, Develop Finance and Implement Projects, Create Early Successes, Evaluate Effectiveness and Revise as Needed) for this property., Develop Goals Topics: Market analysis, Policies/deployment programs, Co-benefits assessment, - Macroeconomic Resource Type: Software/modeling tools User Interface: Desktop Application Website: www.regionaldynamics.com/

458

Chaotic dynamics in accelerator physics. Progress report  

SciTech Connect

Substantial progress was in several areas of accelerator dynamics. For developing understanding of longitudinal adiabatic dynamics, and for creating efficiency enhancements of recirculating free-electron lasers, was substantially completed. A computer code for analyzing the critical KAM tori that bound the dynamic aperture in circular machines was developed. Studies of modes that arise due to the interaction of coating beams with a narrow-spectrum impedance have begun. During this research educational and research ties with the accelerator community at large have been strengthened.

Cary, J.R.

1992-11-30T23:59:59.000Z

459

Dynamic Operational Risk Assessment with Bayesian Network  

E-Print Network (OSTI)

Oil/gas and petrochemical plants are complicated and dynamic in nature. Dynamic characteristics include ageing of equipment/components, season changes, stochastic processes, operator response times, inspection and testing time intervals, sequential dependencies of equipment/components and timing of safety system operations, all of which are time dependent criteria that can influence dynamic processes. The conventional risk assessment methodologies can quantify dynamic changes in processes with limited capacity. Therefore, it is important to develop method that can address time-dependent effects. The primary objective of this study is to propose a risk assessment methodology for dynamic systems. In this study, a new technique for dynamic operational risk assessment is developed based on the Bayesian networks, a structure optimal suitable to organize cause-effect relations. The Bayesian network graphically describes the dependencies of variables and the dynamic Bayesian network capture change of variables over time. This study proposes to develop dynamic fault tree for a chemical process system/sub-system and then to map it in Bayesian network so that the developed method can capture dynamic operational changes in process due to sequential dependency of one equipment/component on others. The developed Bayesian network is then extended to the dynamic Bayesian network to demonstrate dynamic operational risk assessment. A case study on a holdup tank problem is provided to illustrate the application of the method. A dryout scenario in the tank is quantified. It has been observed that the developed method is able to provide updated probability different equipment/component failure with time incorporating the sequential dependencies of event occurrence. Another objective of this study is to show parallelism of Bayesian network with other available risk assessment methods such as event tree, HAZOP, FMEA. In this research, an event tree mapping procedure in Bayesian network is described. A case study on a chemical reactor system is provided to illustrate the mapping procedure and to identify factors that have significant influence on an event occurrence. Therefore, this study provides a method for dynamic operational risk assessment capable of providing updated probability of event occurrences considering sequential dependencies with time and a model for mapping event tree in Bayesian network.

Barua, Shubharthi

2012-08-01T23:59:59.000Z

460

Swarm Intelligence for Urban Dynamics Modelling  

Science Conference Proceedings (OSTI)

In this paper, we propose swarm intelligence algorithms to deal with dynamical and spatial organization emergence. The goal is to model and simulate the developement of spatial centers using multi-criteria. We combine a decentralized approach based on emergent clustering mixed with spatial constraints or attractions. We propose an extension of the ant nest building algorithm with multi-center and adaptive process. Typically, this model is suitable to analyse and simulate urban dynamics like gentrification or the dynamics of the cultural equipment in urban area.

Ghnemat, Rawan; Bertelle, Cyrille [LITIS-University of Le Havre 25 rue Philippe Lebon-BP 540 76058 Le Havre cedex (France); Duchamp, Gerard H. E. [LIPN-University of Paris XIII 99 avenue Jean-Baptiste Clement 93430 Villetaneuse (France)

2009-04-16T23:59:59.000Z

Note: This page contains sample records for the topic "ultrafast solvation dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Dynamical conformal transformation and classical Euclidean wormholes  

E-Print Network (OSTI)

We investigate the necessary condition for the existence of classical Euclidean wormholes in a conformally non-invariant gravitational model minimally coupled to an scalar field. It is shown that while the original Ricci tensor with positive eigenvalues does not allow the Euclidean wormholes to occur, under dynamical conformal transformations the Ricci tensor, with respect to the original metric, is dynamically coupled with the conformal field and its eigenvalues may become negative allowing the Euclidean wormholes to occur. Therefore, it is conjectured that dynamical conformal transformations may provide us with {\\it effective} forms of matter sources leading to Euclidean wormholes in conformally non-invariant systems.

F. Darabi

2010-12-05T23:59:59.000Z

462

The Dynamic Constitutive Response of Four Light Metals: Al 7039 ...  

Science Conference Proceedings (OSTI)

Presentation Title, The Dynamic Constitutive Response of Four Light Metals: Al 7039, ... Atomistically-Informed Dislocation Dynamics Simulations of High Rate ...

463

Laboratory Equipment - DynaPro NanoStar Dynamic Light ...  

Science Conference Proceedings (OSTI)

DynaPro NanoStar Dynamic Light Scattering. Description: Location: E136. The DynaPro NanoStar is a dynamic light scattering ...

2012-10-31T23:59:59.000Z

464

Open Automated Demand Response Dynamic Pricing Technologies and Demonstration  

E-Print Network (OSTI)

left) and High (right) Electricity Price References..32 Listin response to dynamic electricity prices using the Opena variety of dynamic electricity price structures. In this

Ghatikar, Girish

2010-01-01T23:59:59.000Z

465

Chemical Dynamics, Molecular Energetics, and Kinetics at the Synchrotron  

E-Print Network (OSTI)

novel measurements of chemical dynamics for clusters, Chemical Dynamics, Molecular Energetics, and Kinetics at theUniversity of California Chemical Sciences Division,

Leone, Stephen R.

2010-01-01T23:59:59.000Z

466

NETL: Methane Hydrates - ANS Research Project - Modular Dynamics...  

NLE Websites -- All DOE Office Websites (Extended Search)

Modular Formation Dynamics Tester (MDT) Tool The scientific plan for the Mt. Elbert Prospect includes multiple tests using Schlumbergers Modular Formation Dynamics Tester (MDT)...

467

Integrated Dynamic Electron Solutions, Inc. | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Integrated Dynamic Electron Solutions, Inc. America's Next Top Energy Innovator Challenge 333 likes Integrated Dynamic Electron Solutions, Inc. Lawrence Livermore National...

468

Dynamic Pricing, Advanced Metering, and Demand Response in Electricity Markets  

E-Print Network (OSTI)

as Large Comm. Interval metering system with monthly dataDynamic Pricing, Advanced Metering and Demand Response inE Dynamic Pricing, Advanced Metering, and Demand Response in

Borenstein, Severin; Jaske, Michael; Rosenfeld, Arthur

2002-01-01T23:59:59.000Z

469

A first-generation prototype dynamic residential window  

E-Print Network (OSTI)

Prototype Dynamic Residential Window Christian Kohler, HowdyGoudey, and Dariush Arasteh Windows and Daylighting Grouphighly efficient dynamic window that maximizes solar heat

Kohler, Christian; Goudey, Howdy; Arasteh, Dariush

2004-01-01T23:59:59.000Z

470

Quantum dynamics of elementary reactions in the gas phase and...  

NLE Websites -- All DOE Office Websites (Extended Search)

Quantum dynamics of elementary reactions in the gas phase and on surfaces Quantum Dynamics of Elementary Reactions in the Gas Phase and on Surfaces Key Challenges: This research...

471

Dynamic Reduction of a CH4/Air Chemical Mechanism Appropriate...  

NLE Websites -- All DOE Office Websites (Extended Search)

Dynamic Reduction of a CH4Air Chemical Mechanism Appropriate for Investigating Vortex Flame Interactions Title Dynamic Reduction of a CH4Air Chemical Mechanism Appropriate for...

472

Nuclear chiral dynamics and thermodynamics  

E-Print Network (OSTI)

This presentation reviews an approach to nuclear many-body systems based on the spontaneously broken chiral symmetry of low-energy QCD. In the low-energy limit, for energies and momenta small compared to a characteristic symmetry breaking scale of order 1 GeV, QCD is realized as an effective field theory of Goldstone bosons (pions) coupled to heavy fermionic sources (nucleons). Nuclear forces at long and intermediate distance scales result from a systematic hierarchy of one- and two-pion exchange processes in combination with Pauli blocking effects in the nuclear medium. Short distance dynamics, not resolved at the wavelengths corresponding to typical nuclear Fermi momenta, are introduced as contact interactions between nucleons. Apart from a set of low-energy constants associated with these contact terms, the parameters of this theory are entirely determined by pion properties and low-energy pion-nucleon scattering observables. This framework (in-medium chiral perturbation theory) can provide a realistic description of both isospin-symmetric nuclear matter and neutron matter. The importance of three-body forces is emphasized, and the role of explicit Delta(1232)-isobar degrees of freedom is investigated in detail. Nuclear chiral thermodynamics is developed and a calculation of the nuclear phase diagram is performed. This includes a successful description of the first-order phase transition from a nuclear Fermi liquid to an interacting Fermi gas and the coexistence of these phases below a critical temperature T_c. Density functional methods for finite nuclei based on this approach are also discussed. Effective interactions, their density dependence and connections to Landau Fermi liquid theory are outlined. Finally, the density and temperature dependence of the chiral (quark) condensate is investigated.

J. W. Holt; N. Kaiser; W. Weise

2013-04-23T23:59:59.000Z

473

Studies in Chaotic adiabatic dynamics  

Science Conference Proceedings (OSTI)

Chaotic adiabatic dynamics refers to the study of systems exhibiting chaotic evolution under slowly time-dependent equations of motion. In this dissertation the author restricts his attention to Hamiltonian chaotic adiabatic systems. The results presented are organized around a central theme, namely, that the energies of such systems evolve diffusively. He begins with a general analysis, in which he motivates and derives a Fokker-Planck equation governing this process of energy diffusion. He applies this equation to study the {open_quotes}goodness{close_quotes} of an adiabatic invariant associated with chaotic motion. This formalism is then applied to two specific examples. The first is that of a gas of noninteracting point particles inside a hard container that deforms slowly with time. Both the two- and three-dimensional cases are considered. The results are discussed in the context of the Wall Formula for one-body dissipation in nuclear physics, and it is shown that such a gas approaches, asymptotically with time, an exponential velocity distribution. The second example involves the Fermi mechanism for the acceleration of cosmic rays. Explicit evolution equations are obtained for the distribution of cosmic ray energies within this model, and the steady-state energy distribution that arises when this equation is modified to account for the injection and removal of cosmic rays is discussed. Finally, the author re-examines the multiple-time-scale approach as applied to the study of phase space evolution under a chaotic adiabatic Hamiltonian. This leads to a more rigorous derivation of the above-mentioned Fokker-Planck equation, and also to a new term which has relevance to the problem of chaotic adiabatic reaction forces (the forces acting on slow, heavy degrees of freedom due to their coupling to light, fast chaotic degrees).

Jarzynski, C.

1994-01-01T23:59:59.000Z

474

Frontiers in Chemical Physics and Analysis Seminar Series  

E-Print Network (OSTI)

Frontiers in Chemical Physics and Analysis Seminar Series Aqueous Solvation in Extreme Conditions the application of classical chemical dynamics simulations possible for a broad range of problems. However, since

475

Microscopic Description of Nuclear Fission Dynamics  

E-Print Network (OSTI)

We discuss possible avenues to study fission dynamics starting from a time-dependent mean-field approach. Previous attempts to study fission dynamics using the time-dependent Hartree-Fock (TDHF) theory are analyzed. We argue that different initial conditions may be needed to describe fission dynamics depending on the specifics of the fission phenomenon and propose various approaches towards this goal. In particular, we provide preliminary calculations for studying fission following a heavy-ion reaction using TDHF with a density contraint. Regarding prompt muon-induced fission, we also suggest a new approach for combining the time-evolution of the muonic wave function with a microscopic treatment of fission dynamics via TDHF.

A. S. Umar; V. E. Oberacker; J. A. Maruhn; P. -G. Reinhard

2010-03-22T23:59:59.000Z

476

Phonostat: Thermostatting phonons in molecular dynamics simulations  

E-Print Network (OSTI)

Thermostat algorithms in a molecular dynamics simulation maintain an average temperature of a system by regulating the atomic velocities rather than the internal degrees of freedom. Herein, we present a “phonostat” algorithm ...

Raghunathan, Rajamani

477

The Dynamics of Warm and Cold Climates  

Science Conference Proceedings (OSTI)

The atmospheric dynamics of five different climate simulations with the GISS GCM are compared to investigate the changes that occur as climate warms or cools. There are two ice age simulations, the current and doubled CO2 climates, and a ...

D. Rind

1986-01-01T23:59:59.000Z

478

Dynamic LES Modeling of a Diurnal Cycle  

Science Conference Proceedings (OSTI)

The diurnally varying atmospheric boundary layer observed during the Wangara (Australia) case study is simulated using the recently proposed locally averaged scale-dependent dynamic subgrid-scale (SGS) model. This tuning-free SGS model enables ...

Sukanta Basu; Jean-François Vinuesa; Andrew Swift

2008-04-01T23:59:59.000Z

479

Dynamic Phase Transitions in Coupled Motor Proteins  

E-Print Network (OSTI)

The effect of interactions on dynamics of coupled motor proteins is investigated theoretically. A simple stochastic discrete model, that allows to calculate explicitly the dynamic properties of the system, is developed. It is shown that there are two dynamic regimes, depending on the interaction between the particles. For strong interactions the motor proteins move as one tight cluster, while for weak interactions there is no correlation in the motion of the proteins, and the particle separation increases steadily with time. The boundary between two dynamic phases is specified by a critical interaction that has a non-zero value only for the coupling of the asymmetric motor proteins, and it depends on the temperature and the transitions rates. At the critical interaction there is a change in a slope for the mean velocities and a discontinuity in the dispersions of the motor proteins as a function of the interaction energy.

Evgeny B. Stukalin; Anatoly B. Kolomeisky

2005-09-16T23:59:59.000Z

480

Cyclotron Resonances in Electron Cloud Dynamics  

Science Conference Proceedings (OSTI)

A new set of resonances for electron cloud dynamics in the presence of a magnetic field has been found. For short beam bunch lengths and low magnetic fields where lbstripes" found for non-resonant cases. Simulations with the 2D computer code POSINST, as well as a single-particle tracking code, were used to elucidate the physics of the dynamics. The existence of the resonances has been confirmed in experiments at PEP-II. The resonances are expected to affect the electron cloud dynamics in the fringe fields of conventional lattice magnets and in wigglers, where the magnetic fields are low. Results of the simulations and experimental observations, the reason for the bunch-length dependence, and details of the dynamics are discussed here.

Celata, C. M.; Furman, Miguel A.; Vay, J.-L.; Ng, J. S.T.; Grote, D. P.; Pivi, M. T. F.; Wang, L. F.

2009-04-29T23:59:59.000Z

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481

Cyclotron Resonances in Electron Cloud Dynamics  

Science Conference Proceedings (OSTI)

A new set of resonances for electron cloud dynamics in the presence of a magnetic field has been found. For short beam bunch lengths and low magnetic fields where l{sub b} stripes' of multipactoring found for non-resonant cases. Simulations with the 2D computer code POSINST, as well as a single-particle tracking code, were used to elucidate the physics of the dynamics. The resonances are expected to affect the electron cloud dynamics in the fringe fields of conventional lattice magnets and in wigglers, where the magnetic fields are low. Results of the simulations, the reason for the bunch-length dependence, and details of the dynamics will be discussed.

Celata, C M; Furman, M A; Vay, J L; Grote, D P; Ng, J T; Pivi, M F; Wang, L F

2009-05-05T23:59:59.000Z

482

Probing the Environment with Galaxy Dynamics  

E-Print Network (OSTI)

I present various projects to study the halo dynamics of elliptical galaxies. This allows one to study the outer mass and orbital distributions of ellipticals in different environments, and the inner distributions of groups and clusters themselves.

Aaron J. Romanowsky

2006-05-02T23:59:59.000Z

483

Definition: Dynamic Pricing Program | Open Energy Information  

Open Energy Info (EERE)

Pricing Program Pricing Program Jump to: navigation, search Dictionary.png Dynamic Pricing Program Dynamic pricing refers to the family of rates that offer customers time-varying electricity prices on a day-ahead or real-time basis.[1] Related Terms electricity generation References ↑ https://www.smartgrid.gov/category/technology/dynamic_pricing_program [[C LikeLike UnlikeLike You like this.Sign Up to see what your friends like. ategory: Smart Grid Definitionssmart grid,smart grid, |Template:BASEPAGENAME]]smart grid,smart grid, Retrieved from "http://en.openei.org/w/index.php?title=Definition:Dynamic_Pricing_Program&oldid=502620" Category: Definitions What links here Related changes Special pages Printable version Permanent link Browse properties 429 Throttled (bot load)

484

Dynamic Glazing from a Material Science Perspective  

NLE Websites -- All DOE Office Websites (Extended Search)

Dynamic Glazing from a Material Science Perspective Dynamic Glazing from a Material Science Perspective Speaker(s): Sunnie Lim Date: February 16, 2012 - 12:00pm Location: 90-3122 Seminar Host/Point of Contact: Dragan Charlie Curcija Advanced window technology has been identified as a component which can greatly reduce the energy consumption of the building envelope. The next generation of advanced windows will involve a "smart-coating" technology where the optical and solar properties can be dynamically controlled. The performance of such coating is ultimately linked to its materials properties such as chemical composition and microstructure. These properties are directly influenced by the deposition process conditions. A promising dynamic windows technology is based upon the electrochromism process. An electrochromic window system consists of a sandwich of

485

A Dynamic Model of Thundercloud Electric Fields  

Science Conference Proceedings (OSTI)

A dynamic interactive computer model of the electrical behavior of a thundercloud surrounded by the distributed atmosphere, earth, ionosphere circuit is described. The electrification mechanisms in the model are represented by current or voltage ...

John S. Nisbet

1983-12-01T23:59:59.000Z

486

Multi-dimensional Dynamic Knowledge Representation  

Science Conference Proceedings (OSTI)

According to Dynamic Logic Programming (DLP), knowledge may be given by a sequence of theories (encoded as logic programs) representing different states of knowledge. These may represent time (e.g. in updates), specificity (e.g. in taxonomies), strength ...

João Alexandre Leite; José Júlio Alferes; Luís Moniz Pereira

2001-09-01T23:59:59.000Z

487

Flexible dynamics of floating wind turbines  

E-Print Network (OSTI)

This work presents Tower Flex, a structural dynamics model for a coupled analysis of offshore floating wind turbines consisting of a tower, a floating platform and a mooring system. In this multi-body, linear frequency-domain ...

Luypaert, Thomas (Thomas J.)

2012-01-01T23:59:59.000Z

488

System dynamics, market microstructure and asset pricing  

E-Print Network (OSTI)

Traditional asset pricing approaches are not able to explain extreme volatility