Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 29 for “"energy relaxation"”.
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Vibrational Energy Relaxation in Liquids
This research was supported by U.S. Army Research Office contract DAAH04-96-1-0038 and Air Force Office of Scientific Research contract F49620-97-1-0056. Partial support is acknowledged from National Science Foundation grant DMR-9714843. I wish to also acknowledge support from AASERT fellowships …
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Internal energy relaxation in nitrogen plasmas
… at NASA Ames Research Center is used to study energy transfers and population distribution of nitrogen molecules due to collisions with atoms. An ab-initio model developed at the University College London (UCL) is used to study electron impact excitation. Initially, the chemical reactor is …
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Energy relaxation and thermal rectification in carbon devices
… a deeper understanding of power dissipation and energy efficiency at the individual device level could have a global impact, affecting all future electronics. In general, power in electronic devices is dissipated in the form of heat and is slowly lost to the environment. Given that all integrated …
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Determining Energy Relaxation Length Scales in Two-Dimensional Electron Gases
… high and the thermal broad- ening of quantised energy levels is minimised. 4.2 K, the temperature of liquid helium, is thought of as relatively warm. Temperatures of 300 mK and below are readily accessible with sorption-pumped helium-3 and 3He/4He dilution refrigerators. At such low tempera- …
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Energy relaxation in disordered insulators irradiated by ultrafast protons: a multiscale approach
In this thesis, we probe energy relaxation of the electron-hole plasma in disordered insulators irradiated with a burst of ultrafast protons using a multiscale approach. We begin with a phenomenological extension of the two-temperature model, which characterises the relaxation using two …
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Infrared Laser Excitation and Fluorescence Spectra: A Study of Intramolecular Vibrational Energy Relaxation
… or absence of intramolecular vibrational relaxation (or more precisely state mixing) from an excited C-H stretch in twenty three representative molecules varying in size from methane to norbornene. Included are aliphatic hydrocarbons, aromatic molecules, ethers, and ketones, including …
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Investigations Into the Physical Mechanisms That Facilitate Transformation Hysteresis in Shape Memory Alloys
Influences of energy dissipative mechanisms are rationalized using a theoretical approach which combines micro-mechanics and thermodynamics into a thermo-mechanical framework. Models are formulated for the thermal and stress hysteresis based on a thermo-mechanical framework so as to shed light into …
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Photo-produced phonons in semiconductors
… may rapidly thermalize the excess carrier energy without optical phonon emission. The heated carrier distribution can directly emit low-$\nu$ acoustic phonons. The cross-over in energy relaxation mechanisms depends upon the continued production of high-$\nu$ phonons in the presence of a …
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Engineering Noise-Protected Superconducting Qubits
… of transmons, which is often dominated by energy relaxation. Here we study the zero-pi qubit, the superconducting circuit-based qubit that can provide simultaneous protection against dephasing and relaxation. Although the noise-protection property of the zero-pi qubit is appealing, it has …
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ΟΛΟΚΛΗΡΩΜΕΝΟΣ ΣΧΕΔΙΑΣΜΟΣ ΔΙΚΤΥΩΝ ΕΝΑΛΛΑΓΗΣ ΘΕΡΜΟΤΗΤΑΣ
… AND AT LAST A NEW METHOD IS SUGGESTED FOR "THE ENERGY RELAXATION" OFMAXIMUM ENERGY RECOVERY NETWORKS. THE STUDY PROVIDES A TOOL TO THE DESIGN ENGINEER FOR THE DEVELOPMENT OF HEAT EXCHANGER NETWORKS WITH MAXIMUM ENERGY RECOVERY.
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Exciton transport and thermodynamics in gallium arsenide quantum wells
… in understanding the spatial transport and energy relaxation of excitons in quantum well systems. I discuss the mechanism of carrier-induced changes in the absorption spectrum of a 210A GaAs multiple quantum well, and show that at moderate densities, the enhanced transmission at the …
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Molecular Dynamics Simulation Studies on Interfacial Dynamics of Proteins
… Subsequent quantum mechanical studies on energy relaxation in proteins GFP and PYP provide insights into the microenvironment of the chromophore and identify energy flow channels that may mediate the kinetics of photochemical reactions such as charge transfer and conformational …
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Fabrication and measurement of a niobium persistent current qubit
… Microwave spectroscopy was used to map the energy level separation between macroscopic quantum states of the qubit system. We measured the intrawell energy relaxation time [tau]d between quantum levels in this particular device. The intrawell relaxation measurements are important in …
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Dynamic imaging of nanoparticles on femtoseconds to minutes time scale at atomic resolution
… technique are the imaging and manipulating of energy transfer in PbS quantum dots, the imaging of polarization-dependent plasmons on gold nanoislands, and the unraveling of the carbon dot's fluorescence mechanism. Building on this success, a femtosecond time-resolved optical setup has been …
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Characterizing Ultrafast Equilibrium Dynamics Using Third-Order Nonlinear Mid-Infrared Spectroscopies
… thermal equilibrium. In this thesis, vibrational energy relaxation and orientational relaxation dynamics were extracted from polarization-dependent pump probe spectroscopy and local environment dynamics surrounding a vibrational probe were detected using two-dimensional infrared …
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The distribution of local enhancement factors in surface enhanced Raman-active substrates and the vibrational dynamics in the liquid phase
… state-resolved measurements of vibrational energy flow in molecules, vibrational energy transfer (VET) and vibrational relaxation (VR) processes are disclosed. Previously our group focused on nontoxic pure liquids, but now we are able to study aqueous solutions and precious or toxic liquids …
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Metastability of Magnetic Nanoparticles in Magnetization Relaxation with Different Dynamics and Distributions of Magnetic Anisotropy
… average lifetime of the magnetization relaxation using kinetic Monte Carlo simulations with the advanced algorithms. We also calculate the lifetime using the absorbing Markov chains method for analytical results. Our results show that the lifetime of the metastable state follows a …
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Vibrational energy transfer in condensed high explosives: Nitromethane
Molecular mechanical energy transfer in energetical materials is investigated because of the likely possibility of a relationship between energy transfer rates and impact sensitivities. Picosecond coherent Raman scattering, and anti-Stokes Raman spectroscopy following an ultrafast temperature and …
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Ultra-low energy electronics for synthetic biological sensors
… tract. First, we present in vivo measurements of energy-harvesting in the gastrointestinal tract in order to set a power budget for the proposed ingestible sensor. The harvester is based on metal electrodes that react with the stomach contents to generate energy. Here we demonstrate 0.23 [mu]W of …
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