Digital Commons Network^™

Optical Implementation Of The Wavelet Transform By Using A Bacteriorhodopsin Film As An Optically Addressed Spatial Light Modulator, Joby Joseph, F. J. Aranda, D.V.G.L.N. Rao, B. S. Decristofano, B. R. Kimball, M. Nakashima

Physics Faculty Publications

An optical system utilizing the photoinduced dichroism in a bacteriorhodopsin film has been demonstrated for the optical implementation of wavelet transforms. The dichroism, induced by the image of a wavelet filter on a bacteriorhodopsin film leads to polarization rotation of the Fourier components of an image. The polarization-rotated Fourier components of an input scene are analyzed with a polarizer to give the wavelet transform components. The dichroism is induced with beams whose profiles are determined by wavelet filters in order to perform the optical wavelet transform.

Continuum Charged D* Spin Alignment At √S =10.5 Gev, G. Brandenburg, Kenneth A. Bloom, Cleo Collaboration

Kenneth Bloom Publications

A measurement of the spin alignment of charged D* mesons produced in continuum e⁺e^- → cc̅ events at √s = 10.5 GeV is presented. This study using 4.72 fb^-1 of CLEO II data shows that there is little evidence of any D* spin alignment.

Hadronic Transitions Υ(2S)→Υ(1S), J. P. Alexander, Kenneth A. Bloom, Cleo Collaboration

Kenneth Bloom Publications

Using a 73.6 pb^-1 data sample of Υ(2S) events collected with the CLEO II detector at the Cornell Electron Storage Ring, we have investigated the hadronic transitions between the Υ(2S) and the Υ(1S). The dipion transition Υ(2S) → Υ(1S) π⁺π^- was studied using two different analysis techniques. Selecting events in which Υ(1S) → e⁺e^-, μ⁺μ^- (‘‘exclusive’’ analysis), and using the Υ(1S) leptonic branching fractions world averages from the PDG review, we obtained Ɓ(Υ(2S) …

Protein Fragmentation Due To Slow Highly Charged Ion Impact, Christiane Ruehlicke, Dieter Schneider, Markus Schneider, Robert D. Dubois, Rod Balhorn

Physics Faculty Research & Creative Works

We present first results of experiments on the fragmentation of biomolecules using highly charged heavy ions. Fragmentation and modification of oligopeptides, such as dimerization and attachment of ionic salt components, have been observed by means of mass spectrometry. Plasmid DNA molecules were imaged with an atomic force microscope after ion irradiation and profound molecular damage was found.

Optimal Atmospheric Compensation For Anisoplanatism In Adaptive-Optical Systems, Matthew R. Whiteley

Theses and Dissertations

Anisoplanatism in adaptive optics (AO) systems is a performance-degrading effect that arises whenever light from the wave-front sensor beacon and light from the object of interest sample different volumes of optical turbulence. This effect occurs if there is either a spatial separation between the object and the beacon, or a spatial separation between the wave-front sensor and phase-compensation aperture, or if both types of separation are present in the AO system. Anisoplanatism results in an increased value of the aperture-averaged residual phase variance after AO compensation, which causes an exponential decrease in system performance. This dissertation offers a theoretical framework …

Measurement Of The Branching Ratios For The Decays Of DS+ To Ηπ+, Η′Π+, Ηρ+, And Η′Ρ+, C. P. Jessop, Kenneth A. Bloom, Cleo Collaboration

Kenneth Bloom Publications

Using a data sample with an integrated luminosity of 3.9 fb^-1 collected in e⁺e^- annihilation with the CLEO-II detector at the Cornell Electron Storage Ring, we have measured the branching ratios for the decay modes D_s⁺ → (η, η′)π⁺ and D_s⁺ → (η, η′)ρ⁺ relative to D_s⁺ → φπ⁺. These decay modes are among the most common hadronic decays of the D_s⁺, and can be related by factorization to the semileptonic decays D_s⁺ → (η, η′)ℓ⁺ν₁ . …

Water Balloon Rupture In Low‐G, Mark M. Weislogel, S. Lichter

Mechanical and Materials Engineering Faculty Publications and Presentations

A qualitative study of the bursting of water balloons in a simulated low-gravity environment was conducted aboard NASA Lewis’s DC-9 aircraft.

The tests were performed to develop techniques to rapidly deploy large liquid drops in a microgravity environment.

Observation Of High Momentum Η′ Production In B Decays, T. E. Browder, Kenneth A. Bloom, Cleo Collaboration

Kenneth Bloom Publications

We report the first observation of B→ η′X transitions with high momentum η′ mesons. We observe 39.0 ± 11.6 B decay events with 2.0 < Pη′ < 2.7 GeV/c, the high momentum region where background from b → c processes is suppressed. We discuss the physical interpretation of the signal, including the possibility that it is due to b → sg* transitions. Given that interpretation, we find Ɓ(B →η′X_s) = [6.2 ± 1.6(stat) ± 1.3(syst) _-1.5^+0.0(bkg)] X 10^-4 for 2.0 < Pη′ < 2.7 GeV/c.

Search For Selectron And Squark Production In E+P Collisions At Hera, J. Breitweg, M. Derrick, D. Krakauer, S. Magill, D. Mikunas, B. Musgrave, J. Repond, R. Stanek, R. L. Talaga, R. Yoshida, H. Zhang, Margarita C. K. Mattingly, F. Anselmo, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, N. Coppola, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, G. Laurenti

Faculty Publications

We have searched for the production of a selectron and a squark in e+p collisions at a center-of-mass energy of 300 GeV using the ZEUS detector at HERA. The selectron and squark are sought in the direct decay into the lightest neutralino in the framework of supersymmetric extensions to the Standard Model which conserve R-parity. No evidence for the production of supersymmetric particles has been found in a data sample corresponding to 46.6 pb-1 of integrated luminosity. We express upper limits on the product of the cross section times the decay branching ratios as excluded regions in the parameter space …

Ultrafast Phenomena: A Laboratory Experiment For Undergraduates, T. D. Donnelly, Carl H. Grossman

Physics & Astronomy Faculty Works

We present a set of experiments that introduce students to ultrafast science. We discuss the relationship between the description of an ultrashort laser pulse in the frequency domain and the time domain. Using experimental results we demonstrate that this relationship is constrained by the lower limit of the Heisenberg uncertainty principle. Students carrying out the experiments will become familiar with ultrafast techniques, such as autocorrelation and laser cavity design, as well as various other concepts such as dispersion, Fourier transformation, interference, and nonlinear optics. (C) 1998 American Association of Physics Teachers.

Ultrafast Phenomena: A Laboratory Experiment For Undergraduates, Thomas D. Donnelly, Carl Grossman

All HMC Faculty Publications and Research

We present a set of experiments that introduce students to ultrafast science. We discuss the relationship between the description of an ultrashort laser pulse in the frequency domain and the time domain. Using experimental results we demonstrate that this relationship is constrained by the lower limit of the Heisenberg uncertainty principle. Students carrying out the experiments will become familiar with ultrafast techniques, such as autocorrelation and laser cavity design, as well as various other concepts such as dispersion, Fourier transformation, interference, and nonlinear optics.

Improved Measurement Of The Pseudoscalar Decay Constant FDS, M. Chada, Kenneth A. Bloom, Cleo Collaboration

Kenneth Bloom Publications

We present a new determination of f_Ds using 5 million e⁺e^- → cc̅ events obtained with the CLEO II detector. Our value is derived from our new measured ratio Γ(D_s⁺ → μ⁺ν)/Γ(D_s⁺ → φ π ⁺) = 0.173±0.023 ±0.035. Using Ɓ(D_s⁺ → φ π ⁺) = (3.6±0.9)%, we extract f_Ds = (280±19±28±34) MeV. We compare this result with various model calculations.

Electric Potential In The Classical Hall Effect: An Unusual Boundary-Value Problem, Matthew J. Moelter, James Evans, Greg Elliot, Martin Jackson

Physics

The classical Hall effect presents a surprisingly unusual and challenging problem in electrostatics, with boundary conditions that are not of Dirichlet, Neumann, or of mixed Dirichlet and Neumann type. These unusual boundary conditions create several difficulties not normally encountered in standard problems, and ultimately lead to expansion of the electric potential in a nonorthogonal basis set. We derive the boundary conditions for the potential in a rectangular geometry, construct a solution for the potential, and discuss the relation between this problem and problems of the standard mixed type. We also address a commonly encountered misconception about the current distribution.

40th Rocky Mountain Conference On Analytical Chemistry

Rocky Mountain Conference on Magnetic Resonance

Final program, abstracts, and information about the 40th annual meeting of the Rocky Mountain Conference on Analytical Chemistry, co-sponsored by the Colorado Section of the American Chemical Society and the Rocky Mountain Section of the Society for Applied Spectroscopy. Held in Denver, Colorado, July 25 - August 1, 1998.

Observation Of B+→ΩK+ And Search For Related B Decays Modes, T. Bergfeld, Kenneth A. Bloom, Cleo Collaboration

Kenneth Bloom Publications

We have searched for two-body charmless decays of B mesons to purely hadronic exclusive final states including ω or φ mesons using data collected with the CLEO II detector. With this sample of 6.6 X 10⁶ B mesons we observe a signal for the ωK⁺ final state, and measure a branching fraction of Ɓ(B⁺→ωK⁺) = (1.5_-0.6^+0.7 ± 0.2) X 10^-5. We also observe some evidence for the φK* final state, and upper limits are given for 22 other decay modes. These results provide the opportunity …

Low Energy Electron Gun Power Control Unit, Chad Fish, Jr Dennison

Senior Theses and Projects

Near-Earth orbiting spacecraft are subject to a variety of physical environmental elements. Of these, natural space plasma and solar radiation produce spacecraft charging. Spacecraft charging consists of surface (external) and deep (internal) dielectric charging.

Natural space plasma is composed of electrons and positively charged atoms called ions. The plasma is generated by energy from solar radiation and high energy particles emitted by geomagnetic storms. The electrons produce a negative current and the ions produce a positive current. Positive photoelectron currents produced by solar radiation of spacecraft surfaces also add to the electrical fluxesⁱ.

As spacecraft move through the …

Magnetic And Magneto-Optic Study Of A Layered Co/Pt - Dysprosium-Iron-Garnet System, J.M. Meldrim, Roger D. Kirby, M.J. Devries, John A. Woollam, David J. Sellmyer

Department of Physics and Astronomy: Faculty Publications

Abstract-We have studied the effects of placing Co/Pt multilayers on dysprosium-iron-garnet doped with bismuth and aluminum. The garnet was deposited by RF-magnetron sputtering and crystallized by rapid thermal annealing. The Co/Pt multilayers were then deposited by DC-magnetron sputtering. The garnet thickness was held constant at lOOO Å while the ColPt multilayer had the form of [3 Å Co/9 Å Pt]_n with n ranging from 1 to 16. Coercivities of the samples ranged from about 300 to 2000 Oe. Kerr rotations were as high as 1.8° and ellipticities up to 2° depending upon the wavelength of light and the number …

Experimental Investigations Of Wavelength And Angular Errors In Holographic Gratings With Non-Bragg-Matched Read Beams, Monish Ranjan Chatterjee, Vivek Ray

Electrical and Computer Engineering Faculty Publications

Perfect Bragg matching is generally desirable for accurate optical interconnections with holographic gratings. In reality, however, gratings may be illuminated by READ beams with non-Bragg-matched angles, or wavelengths, or both. In such cases, the scattered beams are generally misdirected, and may suffer loss of efficiency and possibly more serious errors such as crosstalk noise or missed connections. A conventional wave-vector triad method of analyzing the scattered beam errors leads readily to near-Bragg estimates of the output angular misalignment. However, the READ wave-vector triads appear to indicate a possible wavelength shift in the output beam even with a Bragg-matched READ wavelength, …

Electrical Characteristics And Parallel Operation Of Microhollow Cathode Discharges, Wenhui Shi

Electrical & Computer Engineering Theses & Dissertations

This thesis describes the electrical properties of microhollow cathode discharges with argon as filling gas. The appearance and current-voltage characteristics of microhollow cathode discharges have been recorded. Three kinds of discharge modes (predischarge, hollow cathode discharge and abnormal discharge) have been observed. The range of operation of the hollow cathode discharge has been found to be 0.5 < pD & 5 Torr cm in argon. By reducing the hole diameter to 100 pm, we were able to operate the discharge to atmospheric pressure in a dc mode. The possibility of dc parallel operation of microhollow cathode discharges was explored. Parallel operation could be obtained without individual ballast for discharges with a positive I-V slope greater than 10 V/mA over a voltage range of more than 5 % of the sustaining voltage. For parallel operation outside the range the ballasting is required. This model was explored by using a segmented anode model. The result of the simple calculation coincides well with the experiment result, where a semi-insulator silicon was used as distributed ballast.

Nonlinear Field Dependence Of The Mobility Of A Charge Subjected To A Superposition Of Dichotomous Stochastic Potentials, A. M. Kenkre, Marek Kus, David H. Dunlap, Paul Ernest Parris

Physics Faculty Research & Creative Works

A general prescription is presented to address a large variety of forms of the nonlinear dependence of the static charge mobility on the applied electric field. The system consists of a classical charge subjected to an arbitrarily strong steady state electric field and to a stochastic potential consisting of a linear superposition of an unlimited number of dichotomous potentials in one-dimensional space. It is shown that the nonlinear mobility can be calculated for arbitrary forms of the density function of the individual dichotomous components of the stochastic potential. Specific cases of physical interest are analyzed. One of them provides a …

Reactions Of Oxygen And Nitric Oxide In A Microhollow Electrode Discharge, Joseph L. Desormeaux Jr.

Electrical & Computer Engineering Theses & Dissertations

Microhollow electrode discharges have been developed and researched in the Physical Electronics Research Institute Laboratories. This discharge typically operates in direct current mode. Microhollow electrode discharges are non-thermal discharges that produce electrons with energies greater than 10 electron volts. Passing gas mixtures through non-equilibrium discharges invokes excitation or dissociation of gas molecules.

The scope of my research was to study the effect of the discharge on the chemistry of two gases, oxygen and nitric oxide in nitrogen mixture. Initial experiments were performed in an effort to produce ozone near atmospheric pressure. This seemed possible since the discharge has a high-energy …

Coupled Electrodynamic-Monte Carlo Simulations Of Nanoscale Gaas Terahertz Optical Mixers, Jiang Li

Electrical & Computer Engineering Theses & Dissertations

The concept of mixing or heterodyning has traditionally been used for microwaves and for radio frequency communications. However, the concept can easily be extended into the optical frequency regime. By doing so, the photomixing process can serve as a very versatile tool for both the generation of ultrahigh frequency (terahertz) and the detection of weak optical signals.

The aim of this thesis is to perform a theoretical study of the photomixing process inside GaAs devices as the non-linear elements. A coupled approach which combines the Monte Carlo simulation scheme for the carrier transport, with Maxwell's equation for the electrodynamics, has …

An Injection Modelocked Titanium-Sapphire Laser, James C. Hovater

Electrical & Computer Engineering Theses & Dissertations

I have investigated the possibility of using an injection modelocked Ti-sapphire laser as a illumination source for GaAs photocathodes. A commercial Ti-sapphire laser was modified to accept a seed pulse from a gain-switched diode laser. Modelocked operation was obtained through gain modulation within the Ti-sapphire crystal as a result of injection seeding with a modelocked pulse train from a gain-switched diode laser. The Ti-sapphire laser essentially becomes a pulse amplifier for the diode laser. Unlike conventional modelocked lasers, the pulse repetition rate of this laser can be discretely varied by setting the seed laser repetition rate equal to multiples of …

Vortex Wake And Exhaust Plume Interaction, Including Ground Effect, Ihab Gaber Adam

Mechanical & Aerospace Engineering Theses & Dissertations

Computational modeling and studies of the near-field wake-vortex turbulent flows, far-field turbulent wake-vortex/exhaust-plume interaction for subsonic and High Speed Civil Transport (HSCT) airplane, and wake-vortex/exhaust-plume interaction with the ground are carried out. The three-dimensional, compressible Reynolds-Averaged Navier-Stokes (RANS) equations are solved using the implicit, upwind, Roe-flux-differencing, finite-volume scheme. The turbulence models of Baldwin and Lomax, one-equation model of Spalart and Allmaras and two-equation shear stress transport model of Menter are implemented with the RANS solver for turbulent-flow modeling.

For the near-field study, computations are carried out on a fine grid for a rectangular wing with a NACA-0012 airfoil section and …

High Pressure Radio-Frequency Microhollow Cathode Discharges, Anja Annett Muller

Electrical & Computer Engineering Theses & Dissertations

A new field of microhollow cathode discharges is represented by the RF microhollow cathode discharge. So far, the behavior and related physical processes of the RF microhollow cathode discharge are not well investigated.

RF microhollow discharges in air at high pressures were investigated under different experimental conditions. The geometry was changed by reducing the cathode hole diameter and the dielectric spacer thickness. By adding a noble gas to air, the influence of additive gases was explored. Additionally, the parallel operation of RF microhollow discharges was investigated.

It was shown that stable RF microhollow cathode discharges could only be sustained up …

First Observation Of The Cabibbo Suppressed Decay B+ → D̅0K+, M. Athanas, Kenneth A. Bloom, Cleo Collaboration

Kenneth Bloom Publications

We have observed the decay B⁺ → D̅⁰K⁺, using 3.3 X 10⁶ BB̅ pairs collected with the CLEO II detector at the Cornell Electron Storage Ring. We find the ratio of branching fractions R ≡ Ɓ(B⁺ → D̅⁰K⁺)/Ɓ(B⁺ →D̅⁰π⁺) = 0.055 ± 0.014 ± 0.005.

Phase Formation And Magnetic Properties Of Co-Rare Earth Magnetic Films, Yi Liu, Richard A. Thomas, S.S. Malhotra, Z.S. Shan, Sy_Hwang Liou, David J. Sellmyer

Sy-Hwang Liou Publications

Co–Sm and Co–Pr films were deposited by dc magnetron sputtering. Transmission electron microscopy and magnetic measurement were used to study the microstructure and magnetic property relationship. The nanostructure of the as-deposited Co 19 at. % Sm films consists of two phases: the amorphous phase and the crystallite phase. Upon annealing at 600 °C, the Co₅Sm phase with the Cu₅Ca structure, having grain size of about 20 nm, is obtained along with high coercivity (45 kOe). The as-deposited Co 22 at. % Sm films also have nanostructure similar to the Co 19 at. % films except the …

Coercivity And Exchange Coupling In Prco:Co Nanocomposite Films, J. Ping Liu, Yi Liu, David J. Sellmyer

David Sellmyer Publications

Magnetic hysteresis and intergrain exchange coupling in nanostructured PrCo:Co composite films have been investigated. The composite thin films were made by multilayer sputtering and subsequent annealing. It is found that the coercivity mechanism is related to film morphology, especially the Co phase fraction. Evidence for the hard-soft-phase exchange coupling has been found and high energy products have been obtained.

Nanostructured Ndfeb Films Processed By Rapid Thermal Annealing, M. Yu, Yi Liu, Sy_Hwang Liou, David J. Sellmyer

Sy-Hwang Liou Publications

Nanostructured NdFeB films were prepared by magnetron sputtering followed by rapid thermal annealing at a ramp rate of 200 °C/s. Isotropically oriented Nd₂Fe₁₄B crystallites were formed in the films and coercivities up to 20 kOe and remanence ratios up to 0.8 were obtained. Transmission electron microscopy analysis shows that the majority phase of the magnetic layer in the high coercivity films consists of Nd₂Fe₁₄B nanocrystallites with an average size of about 50 nm. These nanocrystallites are believed to be single-domain particles, which are responsible for the high coercivities. MFM measurements show that …

Pressure Ionization And Line Merging In Strongly Coupled Plasmas Produced By 100-Fs Laser Pulses, M. Nantel, G. Ma, S. Gu, C.Y. Côté, J. Itatani, Donald Umstadter

Donald Umstadter Publications

Time- and space-resolved extreme ultraviolet spectra of carbon plasmas, created with 100-fs laser pulses, are obtained with the novel technique of picosecond jitter-free streak-camera averaging. Spectroscopic diagnostics indicate electron densities and temperatures evolving from 10²³ to 10²¹ cm^-3 and 80 to 50 eV, respectively, implying less than one particle in a Debye sphere at early times. The emission reveals conditions of extreme pressure ionization and line merging. Comparisons of the experimental spectra with numerical simulations validate the use of the Inglis-Teller limit for line merging, and confirm that pressure ionization models based on the Debye-Huckel potential are …