Front Matter,
2013
SUNY Stony Brook
Front Matter, Konstantin Likharev
Essential Graduate Physics
Includes: Copyright and License; Preface; Disclaimer; Versions, Corrections, and Acknowledgments; Solution Request Templates; Notation; General Table of Contents
Correlating Fiber Quality Assurance Tests For The Nova Far Detector Modules,
2013
Linfield College
Correlating Fiber Quality Assurance Tests For The Nova Far Detector Modules, Amanda K. Bowers
Senior Theses
In an effort to better understand the most fundamental units of matter, physicists are drawn to study the elusive neutrino. Measuring various parameters of neutrinos resulting from their oscillations between three different flavor states can lead to an explanation for the asymmetry between matter and antimatter in the universe. Because they are massless and weakly interacting, detecting these leptons has been a challenging feat. However, large-scale collaborations, such as NOvA, are now able to build detectors that capture information about a neutrino's interaction with atomic matter. During their propagation through space, neutrinos oscillate between various flavor states. Physicists are …
A First Search For Coincident Gravitational Waves And High Energy Neutrinos Using Ligo, Virgo And Antares Data From 2007,
2013
Polytechnic University of Valencia
A First Search For Coincident Gravitational Waves And High Energy Neutrinos Using Ligo, Virgo And Antares Data From 2007, S. Adrián-Martínez, I. Al Samarai, A. Albert, M. André, M. Anghinol, G. Anton, S. Anvar, Marc Favata, Shaon Ghosh, Rodica Martin
Department of Physics and Astronomy Faculty Scholarship and Creative Works
We present the results of the first search for gravitational wave bursts associated with high energy neutrinos. Together, these messengers could reveal new, hidden sources that are not observed by conventional photon astronomy, particularly at high energy. Our search uses neutrinos detected by the underwater neutrino telescope ANTARES in its 5 line configuration during the period January - September 2007, which coincided with the fifth and first science runs of LIGO and Virgo, respectively. The LIGO-Virgo data were analysed for candidate gravitational-wave signals coincident in time and direction with the neutrino events. No significant coincident events were observed. We place …
A Gtc Study Of The Afterglow And Host Galaxy Of The Short-Duration Grb 100816a,
2013
Boise State University
A Gtc Study Of The Afterglow And Host Galaxy Of The Short-Duration Grb 100816a, J. P. Norris
Physics Faculty Publications and Presentations
We present the results from an optical monitoring campaign aimed at studying the afterglow properties of the short GRB 100816A. We implemented a new way of processing the Swift-BAT data, and based on it we reclassified this burst as short, discarding the initial classification as long. Observations were carried out mainly with the GTC Telescope within the four following days after the burst to investigate the optical photometry of its afterglow, and a year later to localize the host. We completed the optical imaging with the 1.23 m and 3.5 m CAHA Telescopes. We built and fitted the nIR-optical …
Hydroxyl-Decorated Graphene Systems As Candidates For Organic Metal-Free Ferroelectrics, Multiferroics, And High-Performance Proton Battery Cathode Materials,
2013
Virginia Commonwealth University
Hydroxyl-Decorated Graphene Systems As Candidates For Organic Metal-Free Ferroelectrics, Multiferroics, And High-Performance Proton Battery Cathode Materials, Menghao Wu, J. D. Burton, Evgeny Y. Tsymbal, Xiao Cheng Zeng, Puru Jena
Physics Publications
Using a first-principles method we show that graphene based materials, functionalized with hydroxyl groups, constitute a class of multifunctional, lightweight, and nontoxic organic materials with functional properties such as ferroelectricity, multiferroicity, and can be used as proton battery cathode materials. For example, the polarizations of semihydroxylized graphane and graphone, as well as fully hydroxylized graphane, are much higher than any organic ferroelectric materials known to date. Further, hydroxylized graphene nanoribbons with proton vacancies at the end can have much larger dipole moments. They may also be applied as high-capacity cathode materials with a specific capacity that is six times larger …
The Effect Of Sulfur Covalent Bonding On The Electronic Shells Of Silver Clusters,
2013
Virginia Commonwealth University
The Effect Of Sulfur Covalent Bonding On The Electronic Shells Of Silver Clusters, Anthony F. Pedicini, Arthur C. Reber, Shiv N. Khanna
Physics Publications
The nature of the bonding in Ag n S m 0/− clusters, n = 1–7; m = 1–4, has been analyzed to understand its effect on the electronic shell structure of silver clusters. First-principle investigations reveal that the sulfur atoms prefer 2 or 3-coordinate sites around a silver core, and that the addition of sulfur makes the planar structures compact. Molecular orbital analysisfinds that the 3p orbitals of sulfur form a bonding orbital and two weakly bonding lone pairs withsilver. We examine the electronic shell structures of Ag 6Sm, which are two electrons deficient of a spherical closed electronic shell …
Communication: In Search Of Four-Atom Chiral Metal Clusters,
2013
Johns Hopkins University
Communication: In Search Of Four-Atom Chiral Metal Clusters, Xinxing Zhang, Bradley Visser, Martin Tschurl, Evan Collins, Yi Wang, Qian Wang, Yawei Li, Qiang Sun, Puru Jena, Gerd Gantefoer, Ulrich Boesl, Ulrich Heiz, Kit H. Bowen Jr.
Physics Publications
A combined study utilizing anion photoelectron spectroscopy and density functional theory was conducted to search for four-atom, chiral, metal, and mostly metal clusters. The clusters considered were AuCoMnBi−/0, AlAuMnO−/0, AgMnOAl−/0, and AuAlPtAg−/0, where the superscripts, −/0, refer to anionic and neutral cluster species, respectively. Based on the agreement of experimentally and theoretically determined values of both electron affinities and vertical detachment energies, the calculated cluster geometries were validated and examined for chirality. Among both anionic and neutral clusters, five structures were identified as beingchiral.
Unusually Large Spin Polarization And Magnetoresistance In A Femg8-Femg8 Superatomic Dimer,
2013
Virginia Commonwealth University, Huazhong University of Science and Technology
Unusually Large Spin Polarization And Magnetoresistance In A Femg8-Femg8 Superatomic Dimer, Lin Zhu, Meichun Qian, Shiv N. Khanna
Physics Publications
Electronic transport across a FeMg8 magnetic superatom and its dimer has been investigated using a density functional theory combined with Keldysh nonequilibrium Green's-function formalism. For a single cluster, our studies for the cluster supported in various orientations on a Au(100) surface show that the transport is sensitive to the contact geometry. Investigations covering the cases where the axes of Mg square antiprism are 45°, perpendicular, and parallel to the transport direction, show that the equilibrium conductance, transferred charge, and currentpolarizations can all change significantly with orientation. Our studies on the transport across a magnetic superatom dimer FeMg8–FeMg8 focus on the …
Magnetic Properties Of Co2-Xtmxc And Co3-Xtmxc Nanoparticles,
2013
Virginia Commonwealth University
Magnetic Properties Of Co2-Xtmxc And Co3-Xtmxc Nanoparticles, Meichun Qian, Shiv N. Khanna
Physics Publications
Using synthetic chemical approaches, it is now possible to synthesize transition metal carbides nanoparticles with morphology, where the transition metal layers are embedded with intervening layers of carbon atoms. A composite material consisting of Co2C and Co3C nanoparticles has been found to exhibit unusually large coercivity and energy product. Here, we demonstrate that the magnetic moments and the anisotropy can be further enhanced by using a combination of Co and other transition metals (TM). Our studies are based on mixednanoparticles Co2−x TM xC and Co3−x TM xC, in which selected Co sites are replaced with 3d transition elements Cr, Mn, …
Structure And Properties Of Mn4cl9: An Antiferromagnetic Binary Hyperhalogen,
2013
Peking University
Structure And Properties Of Mn4cl9: An Antiferromagnetic Binary Hyperhalogen, Yawei Li, Shunhong Zhang, Qian Wang, Puru Jena
Physics Publications
Calculations based on density functional theory show that the structure of Mn4Cl9 anion is that of a Mn atom at the core surrounded by three MnCl3 moieties. Since Mn is predominantly divalent and MnCl3 is known to be a superhalogen with a vertical detachment energy (VDE) of 5.27 eV, Mn4Cl9 can be viewed as a hyperhalogen with the formula unit Mn(MnCl3)3. Indeed, the calculated VDE of Mn4Cl9 anion, namely 6.76 eV, is larger than that of MnCl3 anion. More importantly, unlike previously discovered hyperhalogens, …
An All-Electron Density Functional Theory Study Of The Structure And Properties Of The Neutral And Singly Charged M-12 And M-13 Clusters: M = Sc-Zn,
2013
Florida A&M University
An All-Electron Density Functional Theory Study Of The Structure And Properties Of The Neutral And Singly Charged M-12 And M-13 Clusters: M = Sc-Zn, G. L. Gutsev, C. W. Weatherford, K. G. Belay, B. R. Ramachandran, P. Jena
Physics Publications
The electronic and geometrical structures of the M 12 and M 13 clusters where M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn along with their singly negatively and positively charged ions are studied using all-electron density functional theory within the generalized gradient approximation. The geometries corresponding to the lowest total energy states of singly and negatively charged ions of V13, Mn12, Co12, Ni 13, Cu 13, Zn 12, and Zn 13 are found to be different from the geometries of the corresponding neutral parents. The computed …
Tunable Thermal Quenching Of Photoluminescence In Mg-Doped P-Type Gan,
2013
Virginia Commonwealth University
Tunable Thermal Quenching Of Photoluminescence In Mg-Doped P-Type Gan, Michael A. Reshchikov, J. D. Mcnamara, S. Fernández-Garrido, R. Calarco
Physics Publications
We have studied the thermal quenching of the ultraviolet luminescence band with a maximum at about 3.25 eV in p-type Mg-doped GaN. The characteristic temperature of the thermal quenching of photoluminescence (PL) gradually shifted to higher temperatures with increasing excitation intensity. This effect is explained by a population inversion of charge carriers at low temperatures, which suddenly converts into a quasiequilibrium population as the temperature increases above the characteristic value. Tunable quenching of PL has been observed only in some of the GaN:Mg samples. The absence of the tunable quenching of PL in another group of GaN:Mg samples is preliminarily …
"Semiconductor Nanoparticles (Or Quantum Dots) In Thin Films Have Been Identified As Possible Sensors…",
2013
University of Alabama in Huntsville
"Semiconductor Nanoparticles (Or Quantum Dots) In Thin Films Have Been Identified As Possible Sensors…", Josiah Mullins
Summer Community of Scholars Posters (RCEU and HCR Combined Programs)
No abstract provided.
Observations Of Quantized Conductance Over Nanowires,
2013
University of Puget Sound
Observations Of Quantized Conductance Over Nanowires, Nick Davenport
Summer Research
Nanowires are conductive wires that have a constrictive width that is only a few atoms across. Scientists are just now starting to look deeper into the properties of nanowires and how they can be useful in the construction of nanostructures. In order to gain a better understanding the properties of nanowires, I will be conducting an experiment that examines how the diameter of the wire compares with its electrical conductive properties, once the wire has been etched down to an atomic level. This process involves using a very controlled method of creating a nanowire. I can use a dilute nitric …
Magnetism Of Films,
2013
University of Nebraska-Lincoln
Magnetism Of Films, Yi Liu, David J. Sellmyer
David Sellmyer Publications
Films of L10-structure Fe50–xCoxPt50 films are synthesized by co-sputtering Fe, Co, and Pt on (001) MgO substrates and Si substrates with in-situ heating at 830°C. The nanostructures and magnetic properties of the films are characterized by X-ray diffraction, transmission electron microscopy, and SQUID. The compositions of the samples Fe50–xCoxPt50 are designed to maintain an atomic (Fe+Co):Pt ratio of 50:50 while increasing the Co content in each successive sample. In all samples, the X-ray diffraction patterns from samples on MgO substrate exhibit three strong peaks, namely L10Fe50–xCoxPt50 (001), (002), and MgO (002). The X-ray and electron diffraction patterns from …
Structural And Magnetic Properties Of Pr-Alloyed Mnbi Nanostructures,
2013
University of Nebraska-Lincoln
Structural And Magnetic Properties Of Pr-Alloyed Mnbi Nanostructures, Parashu Kharel, Shah R. Valloppilly, Xingzhong Li, Wenyong Zhang, Ralph Skomski, Jeffrey E. Shield, David J. Sellmyer
David Sellmyer Publications
The structural and magnetic properties of Pr-alloyed MnBi (short MnBi-Pr) nanostructures with a range of Pr concentrations are investigated. The nanostructures include thin films having Pr concen-trations 0, 2, 3, 5, and 9 at.% and melt-spun ribbons having Pr concentrations 0%, 2%, 4%, and 6%, respectively. Addition of Pr into the MnBi lattice has produced a significant change in the magnetic properties of these nanostructures, including an increase in coercivity and structural phase transition temperature, and a decrease in saturation magnetization and anisotropy energy. The highest value of coercivity measured in the films is 23 kOe and in the ribbons …
Low Temperature Ordering And High (001) Orientation Of [Fe/Pt/Cu]18 Multilayer Films,
2013
Jilin University
Low Temperature Ordering And High (001) Orientation Of [Fe/Pt/Cu]18 Multilayer Films, Yongsheng Yu, Xingzhong Li, T A. George, W D. Fei, Haibo Li, David J. Sellmyer
David Sellmyer Publications
[Fe/Pt/Cu]18 multilayer films with different Cu thicknesses were prepared on thermally oxidized Si (111) substrates at room temperature using dc- and rf-magnetron sputtering. The magnetic proper-ties and microstructure of [Fe/Pt/Cu]18 multilayer films annealed at various temperatures have been investigated. Compared with pure [Fe/Pt]18 multilayer films low-temperature ordering and (001) ori-entation in the annealed films with Cu volume concentration below 20% can be obtained. During annealing process Cu atoms diffused into FePt lattice which enhanced the diffusion of Fe and Pt atoms and the grain growth of the films. The perpendicular anisotropy and hard magnetic properties of the …
One-Pot Synthesis Of Urchin-Like Fepd−Fe3O4 And Their Conversion Into Exchange-Coupled L10−Fepd−Fe Nanocomposite Magnets,
2013
Brown University
One-Pot Synthesis Of Urchin-Like Fepd−Fe3O4 And Their Conversion Into Exchange-Coupled L10−Fepd−Fe Nanocomposite Magnets, Yongsheng Yu, Kewei Sun, Yuan Tian, Xingzhong Li, Matthew J. Kramer, David J. Sellmyer, Jeffrey E. Shield, Shouheng Sun
David Sellmyer Publications
We report a one-pot synthesis of urchin-like FePd−Fe3O4 nanocomposites, spherical clusters of FePd nanoparticles (NPs) with spikes of Fe3O4 nanorods (NRs), via controlled thermal decomposition of Fe(CO)5 and reduction of Pd(acac)2. The FePd NPs with sizes between 6 and 9 nm self-aggregate into 60 nm superparticles (SPs), and Fe3O4 NRs grow on the surface of these SPs. Reductive annealing at 500°C converts the FePd−Fe3O4 into exchange-coupled nanocomposites L10−FePd−Fe with their Hc tunable from 0.8 to 2.6 kOe and Ms controlled from 90 to …
Proton Transfer In Surface-Stabilized Chiral Motifs Of Croconic Acid,
2013
University of Nebraska-Lincoln
Proton Transfer In Surface-Stabilized Chiral Motifs Of Croconic Acid, Donna A. Kunkel, James Hooper, Scott Simpson, Geoffrey Rojas, Stephen Ducharme, Timothy Usher, Eva Zurek, Axel Enders
Stephen Ducharme Publications
The structure and cooperative proton ordering of two-dimensional sheets of croconic acid were studied with scanning tunneling microscopy and first-principles calculations. Unlike in the crystalline form, which exhibits a pleated, densely packed polar sheet structure, the confinement of the molecules to the surface results in hydrogenbonded chiral clusters and networks. First-principles calculations suggest that the surface stabilizes networks of configurational isomers, which arise from direct hydrogen transfer between their constituent croconic acid monomers. Some of these configurations have a net polarization. It is demonstrated through constrained molecular dynamics simulations that simultaneous proton transfer between any two molecules can occur spontaneously. …
Optically Pumped Spin-Exchange Polarized-Electron Source,
2013
University of Nebraska
Optically Pumped Spin-Exchange Polarized-Electron Source, Munir Pirbhai, J. Knepper, E. T. Litaker, D. Tupa, Timothy J. Gay
Timothy J. Gay Publications
We describe the operation of a prototype polarized-electron source. Rubidium vapor, contained in a cell, is optically pumped in the presence of a buffer gas. Unpolarized electrons from a tungsten filament are injected into the cell and extracted after undergoing spin exchange with the Rb atoms. We compare the performance of the source when different buffer gases are used. We measure a decrease in electron polarization as their injection energy increases, but find an unexpected regime at higher injection energies yielding increased electron polarization accompanied by a 40-fold increase in current, suggesting the production of slow secondary electrons in the …
