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1: Mass asymmetric fission barriers for {sup 98}Mo; 2: Synthesis and characterization of actinide-specific chelating agents

Description: Excitation functions have been measured for complex fragment emission from the compound nucleus {sup 98}Mo, produced by the reaction of {sup 86}Kr with {sup 12}C. Mass asymmetric fission barriers have been obtained by fitting the excitation functions with a transition state formalism. The extracted barriers are {approximately} 5.7 MeV higher, on average, than the calculations of the Rotating Finite Range Model (RFRM). These data clearly show an isospin dependence of the conditional barriers whe… more
Date: August 1, 1996
Creator: Veeck, A. C.
open access

1. Mono((8)annulene)Uranium(4) half-sandwich complexes, 2. Novel syntheses of symmetrically substituted cyclooctatetetraenes

Description: A reproducible, high-yield synthesis of mono((8)annulene)uranium(4)dichloride (1) is reported, along with the X-ray crystal structural of the bis(pyridine) adduct. Metathesis reactions of the half-sandwich complex 1 with a variety of simple alkyl and alkoxy reagents failed to generate any isolable mono-ring complexes. Reactions of 1 with polydentate, delocalized anions did produce stable derivatives, including mono((8)annulene)uranium(4)bis(acetylacetonate) (4). An X-ray crystal structure of 4 … more
Date: October 1991
Creator: Boussie, Thomas Richard
open access

1. Mono([8]annulene)Uranium(4) half-sandwich complexes, 2. Novel syntheses of symmetrically substituted cyclooctatetetraenes

Description: A reproducible, high-yield synthesis of mono([8]annulene)uranium(4)dichloride (1) is reported, along with the X-ray crystal structural of the bis(pyridine) adduct. Metathesis reactions of the half-sandwich complex 1 with a variety of simple alkyl and alkoxy reagents failed to generate any isolable mono-ring complexes. Reactions of 1 with polydentate, delocalized anions did produce stable derivatives, including mono([8]annulene)uranium(4)bis(acetylacetonate) (4). An X-ray crystal structure of 4 … more
Date: October 1, 1991
Creator: Boussie, T. R.
open access

1: Redox chemistry of bimetallic fulvalene complexes; 2: Oligocyclopentadienyl complexes

Description: The electrochemistry of the heterobimetallic complexes (fulvalene)WFe(CO){sub 5} (30) and (fulvalene)WRu(CO){sub 5} (31) has been investigated. Compound 30 is reduced in two one-electron processes, and this behavior was exploited synthetically to prepare a tetranuclear dimer by selective metal reduction. Complex 31 displayed a distinction between the metals upon reoxidation of the dianion, allowing the formation of a dimer by selective metal anion oxidation. The redox behavior of 30 led to an i… more
Date: November 1, 1993
Creator: Brown, D. S.
open access

A 3% Measurement of the Beam Normal Single Spin Asymmetry in Forward Angle Elastic Electron-Proton Scattering using the Qweak Setup

Description: The beam normal single spin asymmetry generated in the scattering of transversely polarized electrons from unpolarized nucleons is an observable of the imaginary part of the two-photon exchange process. Moreover, it is a potential source of false asymmetry in parity violating electron scattering experiments. The Q{sub weak} experiment uses parity violating electron scattering to make a direct measurement of the weak charge of the proton. The targeted 4% measurement of the weak charge of the pro… more
Date: August 1, 2013
Creator: Waidyawansa, Dinayadura Buddhini
open access

10 microsecond time resolution studies of Cygnus X-1

Description: Time variability analyses have been applied to data composed of event times of X-rays emitted from the binary system Cygnus X-1 to search for unique black hole signatures. The X-ray data analyzed was collected at ten microsecond time resolution or better from two instruments, the High Energy Astrophysical Observatory (HEAO) A-1 detector and the Rossi X-ray Timing Explorer (XTE) Proportional Counter Array (PCA). HEAO A-1 and RXTE/PCA collected data from 1977--79 and from 1996 on with energy sens… more
Date: June 1, 1997
Creator: Wen, H.C.
open access

The ^2H(e,e'p)n Reaction at High Four-Momentum Transfer

Description: This dissertation presents the highest four-momentum transfer, Q^2,quasielastic (x_Bj = 1) results from Experiment E01-020 which systematically explored the 2He(e,e'p)n reaction ("Electro-disintegration" of the deuteron) at three different four-momentum transfers, Q^2 = 0.8, 2.1, and 3.5 GeV^2 and missing momenta, P_miss = 0, 100, 200, 300, 400, and 500 GeV including separations of the longitudinal-transverse interference response function, R_LT, and extractoin of the longitudinal-transverse as… more
Date: December 31, 2006
Creator: Ibrahim, Hassan
open access

A15 superconductors through direct solid-state precipitation: V/sub 3/Ga and Nb/sub 3/Al

Description: A solid-state precipitation process was used to prepare superconducting tapes containing an A15 phase, V/sub 3/Ga or Nb/sub 3/Al, in a ductile niobium or vanadium containing BCC matrix. Ingots weighing as large as 30 to 50 gms of V-(14 approx. 19 at. %) Ga and Nb-(13 approx. 22 at. %) Al were prepared by arc-melting, homogenized, quenched, warm-rolled over 99% into tape, and aged at temperatures in the range 600/sup 0/C to 1000/sup 0/C to precipitate the superconducting A15 phase. The features … more
Date: September 1, 1980
Creator: Hong, M.
open access

Ab initio effective core potentials including relativistic effects and their application to the electronic structure calculations of heavy atoms and molecules

Description: The effects of the 4f shell of electrons and the relativity of valence electrons are compared. The effect of 4f shell (lanthanide contraction) is estimated from the numerical Hartree-Fock (HF) calculations of pseudo-atoms corresponding to Hf, Re, Au, Hg, Tl, Pb and Bi without 4f electrons and with atomic numbers reduced by 14. The relativistic effect estimated from the numerical Dirac-Hartree-Fock (DHF) calculations of those atoms is comparable in the magnitude with that of the 4f shell of elec… more
Date: November 1, 1977
Creator: Lee, Y. S.
open access

Absorption and emission properties of photonic crystals and metamaterials

Description: We study the emission and absorption properties of photonic crystals and metamaterials using Comsol Multiphysics and Ansoft HFSS as simulation tools. We calculate the emission properties of metallic designs using drude model and the results illustrate that an appropriate termination of the surface of the metallic structure can significantly increase the absorption and therefore the thermal emissivity. We investigate the spontaneous emission rate modifications that occur for emitters inside two-… more
Date: August 3, 2007
Creator: Peng, Lili
open access

Absorption, distribution and excretion of inhaled hydrogen fluoride in the rat

Description: Rats were subjected to whole body HF exposure for 6 hrs or to nose-only HF exposure for 1 hr. Total and/or ionic fluoride concentrations in selected tissues were determined at various times following exposure. In rats sacrificed 6 hrs after whole body exposure, dose-dependent increases in lung, plasma, and kidney total and ionic fluoride concentration occurred. Rats excreted more fluoride in the urine after whole body exposure than could be explained by the amount of HF inhaled. Considerable ev… more
Date: January 1, 1979
Creator: Morris, J. B.
open access

AC microcalorimetry of adsorbates on evaporated metal films: Orientational ordering of H₂ multilayers

Description: We have improved and extended a novel ac calorimetric technique for measuring the heat capacity of adsorbates on evaporated metal films. Metallic substrates are of particular interest in current studies of the thermodynamics of adsorbed molecules. The method described in the present work is only calorimetric technique which allows measurements of molecules on simple metallic surfaces. Among other improvements, we have achieved significant progress in the preparation and characterization of the … more
Date: November 1, 1991
Creator: Phelps, R.B.
open access

AC microcalorimetry of adsorbates on evaporated metal films: Orientational ordering of H₂ multilayers

Description: We have improved and extended a novel ac calorimetric technique for measuring the heat capacity of adsorbates on evaporated metal films. Metallic substrates are of particular interest in current studies of the thermodynamics of adsorbed molecules. The method described in the present work is only calorimetric technique which allows measurements of molecules on simple metallic surfaces. Among other improvements, we have achieved significant progress in the preparation and characterization of the … more
Date: November 1, 1991
Creator: Phelps, R. B.
open access

ac power control in the Core Flow Test Loop

Description: This work represents a status report on a development effort to design an ac power controller for the Core Flow Test Loop. The Core Flow Test Loop will be an engineering test facility which will simulate the thermal environment of a gas-cooled fast-breeder reactor. The problems and limitations of using sinusoidal ac power to simulate the power generated within a nuclear reactor are addressed. The transformer-thyristor configuration chosen for the Core Flow Test Loop power supply is presented. T… more
Date: January 1, 1980
Creator: McDonald, D.W.
open access

Accelerated hygrothermal stabilization of composite materials

Description: Experimentation validated a simple moisture conditioning scheme to prepare Gr/Ep composite parts for precision applications by measuring dimensional changes over 90 days. It was shown that an elevated temperature moisture conditioning scheme produced a dimensionally stable part from which precision structures could be built/machined without significant moisture induced dimensional changes after fabrication. Conversely, that unconditioned Gr/Ep composite panels exhibited unacceptably large dimen… more
Date: May 1, 1994
Creator: Gale, J. A.
open access

Accelerating the Loop Expansion

Description: This thesis introduces a new non-perturbative technique into quantum field theory. To illustrate the method, I analyze the much-studied phi/sup 4/ theory in two dimensions. As a prelude, I first show that the Hartree approximation is easy to obtain from the calculation of the one-loop effective potential by a simple modification of the propagator that does not affect the perturbative renormalization procedure. A further modification then susggests itself, which has the same nice property, and w… more
Date: July 29, 1986
Creator: Ingermanson, R.
open access

Acceleration of electrons using an inverse free electron laser auto- accelerator

Description: We present data from our study of a device known as the inverse free electron laser. First, numerical simulations were performed to optimize the design parameters for an experiment that accelerates electrons in the presence of an undulator by stimulated absorption of radiation. The Columbia free electron laser (FEL) was configured as an auto-accelerator (IFELA) system; high power (MW`s) FEL radiation at {approximately}1.65 mm is developed along the first section of an undulator inside a quasi-o… more
Date: July 1, 1992
Creator: Wernick, I. K. & Marshall, T. C.
open access

Accelerator Mass Spectrometry Measurements of Plutonium in Sediment and Seawater from the Marshall Islands

Description: During the summer 2000, I was given the opportunity to work for about three months as a technical trainee at Lawrence Livermore National Laboratory, or LLNL as I will refer to it hereafter. University of California runs this Department of Energy laboratory, which is located 70 km east of San Francisco, in the small city of Livermore. This master thesis in Radioecology is based on the work I did here. LLNL, as a second U.S.-facility for development of nuclear weapons, was built in Livermore in t… more
Date: August 1, 2001
Creator: Leisvik, M & Hamilton, T
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