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A Voltage Controlled Oscillator for a Phase-Locked Loop Frequency Synthesizer in a Silicon-on-Sapphire Process

Description: Engineers from a government-owned engineering and manufacturing facility were contracted by government-owned research laboratory to design and build an S-band telemetry transmitter using Radio Frequency Integrated Circuit (RFIC) technology packaged in a Low-Temperature Co-fired Ceramic (LTCC) Multi-Chip Module. The integrated circuit technology chosen for the Phase-Locked Loop Frequency Synthesizer portion of the telemetry transmitter was a 0.25 um CMOS process that utilizes a sapphire substrat… more
Date: May 21, 2009
Creator: Garrison, Sean
Partner: UNT Libraries Government Documents Department
open access

Development of extreme ultraviolet and soft x-ray multilayer optics for scientific studies with femtosecond/attosecond sources

Description: The development of multilayer optics for extreme ultraviolet (EUV) radiation has led to advancements in many areas of science and technology, including materials studies, EUV lithography, water window microscopy, plasma imaging, and orbiting solar physics imaging. Recent developments in femtosecond and attosecond EUV pulse generation from sources such as high harmonic generation lasers, combined with the elemental and chemical specificity provided by EUV radiation, are opening new opportunities… more
Date: May 21, 2009
Creator: Aquila, Andrew Lee
Partner: UNT Libraries Government Documents Department
open access

On Decays of B Mesons to a Strange Meson and an Eta or Eta' Meson at Babar

Description: We describe studies of the decays of B mesons to final states {eta}K{sup *}(892), {eta}K{sup *}{sub 0}(S-wave), {eta}K{sup *}{sub 2}(1430), and {eta}'K based on data collected with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collier at the Stanford Linear Accelerator Center. We measure branching fractions and charge asymmetries for the decays B {yields} {eta}K{sup *}, where K{sup *} indicates a spin 0, 1, or 2 K{pi} system, making first observations of decays to final st… more
Date: April 21, 2009
Creator: Hirschauer, James Francis
Partner: UNT Libraries Government Documents Department
open access

Study of Rare B-Meson Decays Related to the CPObservable sin(2beta+gamma) at the BABAR Experiment

Description: This study reports the observation of the decays B{sup 0}{yields}D{sup (*)+}{sub S}{pi}{sup -} and B{sup 0}{yields}D{sup (*)-}K{sup +} in a sample of 230 x 10{sup 6} {Upsilon}(4S) {yields} B{bar B} events collected with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} storage ring, located at the Stanford Linear Accelerator Center. The branching fractions {beta}(B{sup 0} {yields} D{sup +}{sub S}{pi}{sup -}) = (1.3 {+-} 0.3 (stat) {+-} 0.2 (syst)) x 10{sup -5}, {beta}(B{sup 0}… more
Date: August 21, 2007
Creator: Orimoto, Toyoko Jennifer
Partner: UNT Libraries Government Documents Department
open access

Reconstruction of B- to D*0 e- anti_nu_e Decays and Determination of |Vcb|

Description: In this analysis the decay B- {yields} D*{sup 0}e{sup -}{bar {nu}}{sub e} is measured. The underlying data sampel consists of about 226 million B{bar B}-pairs accumulated on the {Upsilon}(4S) resonance by the BABAR detector at the asymmetric e{sup +}e{sup -} collider PEP-II. The reconstruction of the decay uses the channels D*{sup 0}{yields}D{sup 0}{pi}{sup 0}, D{sup 0} {yields} K{sup -}{pi}{sup +} and {pi}{sup 0} {yields} {gamma}{gamma}. The neutrino is not reconstructed. Since the rest frame … more
Date: August 21, 2007
Creator: Schubert, Jens
Partner: UNT Libraries Government Documents Department
open access

GaAs Blocked-Impurity-Band Detectors for Far-Infrared Astronomy

Description: High-purity and doped GaAs films have been grown by Liquid-phase epitaxy (LPE) for development of a blocked impurity band (BIB) detector for far-infrared radiation. The film growth process developed has resulted in the capability to grow GaAs with a net active impurity concentration below 1 x 10{sup 13} cm{sup -3}, ideal for the blocking layer of the BIB detector. The growth of n-type LPE GaAs films with donor concentrations below the metal-insulator transition, as required for the absorbing la… more
Date: December 21, 2004
Creator: Cardozo, Benjamin Lewin
Partner: UNT Libraries Government Documents Department
open access

Aspherical supernovae

Description: Although we know that many supernovae are aspherical, the exact nature of their geometry is undetermined. Because all the supernovae we observe are too distant to be resolved, the ejecta structure can't be directly imaged, and asymmetry must be inferred from signatures in the spectral features and polarization of the supernova light. The empirical interpretation of this data, however, is rather limited--to learn more about the detailed supernova geometry, theoretical modeling must been undertak… more
Date: May 21, 2004
Creator: Kasen, Daniel Nathan
Partner: UNT Libraries Government Documents Department
open access

Development of Trivalent Ytterbium Doped Fluorapatites for Diode-Pumped Laser Applications

Description: One of the major motivators of this work is the Mercury Project, which is a 1 kW scalable diode-pumped solid-state laser system under development at Lawrence Livermore National Laboratory (LLNL). Major goals include 100 J pulses, 10% wallplug efficiency, 10 Hz repetition rate, and a 5 times diffraction limited beam. To achieve these goals the Mercury laser incorporates ytterbium doped Sr{sub 5}(PO{sub 4}){sub 3}F (S-FAP) as the amplifier gain medium. The primary focus of this thesis is a full u… more
Date: June 21, 2000
Creator: Bayramian, A. J.
Partner: UNT Libraries Government Documents Department
open access

Benchmarks and models for 1-D radiation transport in stochastic participating media

Description: Benchmark calculations for radiation transport coupled to a material temperature equation in a 1-D slab and 1-D spherical geometry binary random media are presented. The mixing statistics are taken to be homogeneous Markov statistics in the 1-D slab but only approximately Markov statistics in the 1-D sphere. The material chunk sizes are described by Poisson distribution functions. The material opacities are first taken to be constant and then allowed to vary as a strong function of material tem… more
Date: August 21, 2000
Creator: Miller, D. S.
Partner: UNT Libraries Government Documents Department
open access

Nuclear magnetic resonance studies of quadrupolar nuclei and dipolar field effects

Description: Experimental and theoretical research conducted in two areas in the field of nuclear magnetic resonance (NMR) spectroscopy is presented: (1) studies of the coherent quantum-mechanical control of the angular momentum dynamics of quadrupolar (spin I > 1/2) nuclei and its application to the determination of molecular structure; and (2) applications of the long-range nuclear dipolar field to novel NMR detection methodologies.The dissertation is organized into six chapters. The first two chapters… more
Date: December 21, 2004
Creator: Urban, Jeffry Todd
Partner: UNT Libraries Government Documents Department
open access

Towards Chip Scale Liquid Chromatography and High Throughput Immunosensing

Description: This work describes several research projects aimed towards developing new instruments and novel methods for high throughput chemical and biological analysis. Approaches are taken in two directions. The first direction takes advantage of well-established semiconductor fabrication techniques and applies them to miniaturize instruments that are workhorses in analytical laboratories. Specifically, the first part of this work focused on the development of micropumps and microvalves for controlled f… more
Date: September 21, 2000
Creator: Ni, J.
Partner: UNT Libraries Government Documents Department
open access

Sum-frequency spectroscopic studies: I. Surface melting of ice, II. Surface alignment of polymers

Description: Surface vibrational spectroscopy via infrared-visible sum-frequency generation (SFG) has been established as a useful tool to study the structures of different kinds of surfaces and interfaces. This technique was used to study the (0001) face of hexagonal ice (Ih). SFG spectra in the O-H stretch frequency range were obtained at various sample temperatures. For the vapor(air)/ice interface, the degree of orientational order of the dangling OH bonds at the surface was measured as a function of te… more
Date: December 21, 2000
Creator: Wei, Xing
Partner: UNT Libraries Government Documents Department
open access

Transition Metal Complexes of Cr, Mo, W and Mn Containing {eta}{sup 1}(S)-2,5-Dimethylthiophene, Benzothiophene and Dibenzothiophene Ligands

Description: The UV photolysis of hexanes solutions containing the complexes M(CO){sub 6} (M=Cr, Mo, W) or CpMn(CO){sub 3} (Cp={eta}{sup 5}-C{sub 5}H{sub 5}) and excess thiophene (T{sup *}) (T{sup *}=2,5-dimethylthiophene (2,5-Me{sub 2}T), benzothiophene (BT), and dibenzothiophene (DBT)) produces the {eta}{sup 1}(S)-T{sup *} complexes (CO){sub 5}M({eta}{sup 1}(S)-T{sup *}) 1-8 or Cp(CO){sub 2}Mn({eta}{sup 1}(S)-T{sup *})9-11, respectively. However, when T{sup *}=DBT, and M=Mo, a mixture of two products resu… more
Date: September 21, 2000
Creator: Reynolds, M.
Partner: UNT Libraries Government Documents Department
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