UNT Theses and Dissertations - 10 Matching Results

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Accelerator Mass Spectrometry Studies of Highly Charged Molecular Ions

Description: The existence of singly, doubly, and triply charged diatomic molecular ions was observed by using an Accelerator Mass Spectrometry (AMS) technique. The mean lifetimes of 3 MeV boron diatomic molecular ions were measured. No isotopic effects on the mean lifetimes of boron diatomic molecules were observed for charge state 3+. Also, the mean lifetime of SiF^3+ was measured.
Date: December 1994
Creator: Kim, Yong-Dal
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Experimental Synchronization of Chaotic Attractors Using Control

Description: The focus of this thesis is to theoretically and experimentally investigate two new schemes of synchronizing chaotic attractors using chaotically operating diode resonators. The first method, called synchronization using control, is shown for the first time to experimentally synchronize dynamical systems. This method is an economical scheme which can be viably applied to low dimensional dynamical systems. The other, unidirectional coupling, is a straightforward means of synchronization which ca… more
Date: December 1994
Creator: Newell, Timothy C. (Timothy Charles)
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Partner: UNT Libraries
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The Stopping Power of Amorphous and Channelled Silicon at All Energies as Computed with the Binary Encounter Approximation

Description: This thesis utilizes the binary encounter approximation to calculate the stopping power of protons penetrating silicon. The main goal of the research was to make predictions of the stopping power of silicon for low-energy and medium-energy channelled protons, in the hope that this will motivate experiments to test the theory developed below. In attaining this goal, different stopping power theories were compared and the binary encounter approach was applied to random (non-channelled) and high-e… more
Date: December 1994
Creator: Bickel, David, 1970-
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Charge State Dependence of M-Shell X-Ray Production in 67Ho by 2-12 MeV Carbon Ions

Description: The charge state dependence of M-shell x-ray production cross sections of 67HO bombarded by 2-12 MeV carbon ions with and without K-vacancies are reported. The experiment was performed using an NEC 9SDH-2 tandem accelerator at the Ion Beam Modification and Analysis Laboratory of the University of North Texas. The high charge state carbon ions were produced by a post-accelerator stripping gas cell. Ultra-clean holmium targets were used in ion-atom collision to generate M-shell x rays at energies… more
Date: August 1994
Creator: Sun, Hsueh-Li
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Partner: UNT Libraries
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Dielectric Relaxation of Aqueous Solutions at Microwave Frequencies for 335 GHz. Using a Loaded Microwave Cavity Operating in the TM010 Mode

Description: The frequency dependence and temperature dependence of the complex dielectric constant of water is of great interest. The temperature dependence of the physical properties of water given in the literature, specific heat, thermal conductivity, electric conductivity, pH, etc. are compared to the a. c. (microwave) and d. c. conductivity of water with a variety of concentration of different substances such as HC1, NaCl, HaS04, etc. When each of these properties is plotted versus inverse absolute te… more
Date: August 1994
Creator: Wang, Henry F. S. (Henry Fu-Sen)
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Diffusion Kinetics and Microstructure of Eutectic and Composite Solder/Copper Joints

Description: Sn/Pb solders are widely used by the electronics industry to provide both mechanical and electrical interconnections between electronic components and printed circuit boards. Solders with enhanced mechanical properties are required for high reliability for Surface Mount Technology (SMT) applications. One approach to improve the mechanical properties of solder is to add metallic or intermetallic particles to eutectic 63Sn/37Pb solder to form composite solders. Cu6Sn5 and Cu3Sn form and grow at t… more
Date: May 1994
Creator: Wu, Yujing
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Nonlinear Dynamics of Semiconductor Device Circuits and Characterization of Deep Energy Levels in HgCdTe by Using Magneto-Optical Spectroscopy

Description: The nonlinear dynamics of three physical systems has been investigated. Diode resonator systems are experimentally shown to display a period doubling route to chaos, quasiperiodic states, periodic locking states, and Hopf bifurcation to chaos. Particularly, the transition from quasiperiodic states to chaos in line-coupled systems agrees well with the Curry-Yorke model. The SPICE program has been modified to give realistic models for the diode resonator systems.
Date: May 1994
Creator: Yü, Chi
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Scaling Behaviors and Mechanical Properties of Polymer Gels

Description: Polymer gels undergo a volume phase transition in solvent in response to an infinitesimal environmental change. This remarkable phenomenon has resulted in many potential applications of polymer gels. The understanding of its mechanical properties has both scientific and technological importance. For this purpose, we have developed a novel method for measuring Poisson's ratio, which is one of the most important parameters determining the mechanical property of gels. Using this method, Poisson's … more
Date: May 1994
Creator: Li, Chʻun-fang
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Transport Processes in Synchrotrons

Description: This thesis examines the evolution of beams in synchrotrons. Following an introduction to accelerator physics in Chapter 1, in Chapter 2 I describe the Fermilab E778 'diffusion' experiment. Families of sextupoles were powered to drive the 2/5 resonance, and a beam was then kicked to populate a nonlinear region of the transverse phase space. The beam was then observed over periods of approximately 30 minutes for a variety of kick amplitudes and physical apertures. In Chapter 3 comments about the… more
Date: May 1994
Creator: Cole, Benjamin H. (Benjamin Holland)
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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