Thesis (Ph. D.)--University of Washington, 1997. / Vita. Includes bibliographical references (leaves [214]-219).

Thesis (Ph. D.)--University of Washington, 2004. / Vita. Includes bibliographical references (leaves 139-146).

La cavitation acoustique (formation, croissance et effondrement de bulles de gaz dans un liquide soumis aux ultrasons) est à l'origine de réactions chimiques (sonochimie) via la génération de conditions extrêmes lors de l'effondrement des bulles. Des températures de 103-104K et des pressions de l'ordre de 1000 atm sont atteintes au cœur des bulles [1]. Dans ces conditions, les liaisons chimiques des molécules volatiles présentes dans les bulles peuvent être rompues, formant, dans le cas de solutions aqueuses, des radicaux OH et H. Par ailleurs, l'effondrement violent des bulles de cavitation peut être accompagné par l'émission de lumière, sonoluminescence (SL), qui est le sujet d'étude de ce travail. Cette émission lumineuse est formée d'un continuum, de l'UV au proche IR, similaire à l'émission d'un corps noir, sur lequel peuvent se superposer des lignes d'émission atomiques ou moléculaires.On distingue deux types de SL: la SL mono-bulle (SBSL) et la SL multibulle (MBSL). En général, les spectres de MBSL se différencient de ceux de SBSL par la présence de lignes d'émission (d'atomes alcalins, de radicaux hydroxy… [2]), si bien que les mécanismes d'émission ainsi que la nature des conditions à l'intérieur des bulles lors de leur effondrement ont longtemps été considérés comme différents pour les systèmes mono- et multi-bulles. Un pont a été érigé entre les deux systèmes par le travail de Liang et al. [3] qui mit en évidence les conditions expérimentales permettant l'apparition de lignes dans le spectre de SBSL. Dans ce contexte, l'objectif de ce travail était de comparer les émissions de SBSL (27 kHz) et MBSL à haute et basse fréquences (20, 203, 607 kHz) pour différentes solutions aqueuses. Un sonoréacteur monobulle a été développé, dans lequel la température, la nature et la pression de gaz dissous ainsi que la pression acoustique sont contrôlés. Les électrolytes étudiés étaient : NaCl et les chlorures de lanthanides luminescents Ce3+, Tb3+, Eu3+ et Gd3+. Ces derniers peuvent être excités soit par absorption de photons dans l'UV soit par collisions avec des particules énergétiques [4].Dans la première partie de ce travail, les conditions à l'intérieur d'une monobulle lors de son effondrement ont été estimées via un fit du continuum par l'équation de Planck du corps noir. Les températures du corps noir obtenues sont de l'ordre de 104K, en accord avec des études précédentes. Elles sont indépendantes de la présence de NaCl et de la pression acoustique alors que l'intensité de SL y est très sensible. Les résultats obtenus remettent en question l'utilisation du modèle du corps noir en SL. Des lignes d'émission atomique et moléculaire se superposent parfois au continuum de SL : en MBSL, et en SBSL dans certaines conditions particulières (pression d'argon suffisante, faible pression acoustique) [3, 5]. Ce travail met en évidence la similarité entre la forme de l'émission de OH en SBSL et en MBSL à 20kHz, ce qui indique des conditions intrabulles très proches dans les conditions expérimentales étudiées [6]. En SBSL sous 70mbar d'Ar, l'intensité des lignes diminue lorsque la pression acoustique augmente, jusqu'à leur disparition dans le continuum. Cette évolution peut apparaître comme un lien entre SBSL et MBSL.Par ailleurs, cette étude confirme que la concentration en sodium à l'interface bulle-liquide, qui peut être enrichie par l'utilisation d'un contre-ion tensioactif, est le paramètre clé de l'observation de l'émission du sodium en SBSL, suggérant que l'excitation du sodium a lieu soit à l'interface de la bulle, soit en son cœur, après injection de gouttelettes. La seconde partie de cette étude concerne l'effet de la fréquence ultrasonore et de la puissance acoustique sur l'intensité de luminescence des ions lanthanides en MBSL. La luminescence des ions Tb3+, Ce3+ et Eu3+ est ainsi observée. La comparaison des rendements de SL et de photoluminescence indique qu'à l'exception de Ce3+, l'excitation par photons est min / The importance of acoustic cavitation, i.e., the formation, growth and collapse of gaseous cavities in liquid exposed to ultrasound, in sonochemistry is based on the generation of extreme conditions upon bubble collapse. Temperatures and pressures inside the collapsing bubble are approximated to reach 104 K and 1000 atm, respectively [suslick-1999]. Under such conditions chemical bonds of the solvent vapour or volatile solutes present in the bubble core are easily cleaved, which in the case of aqueous systems, leads to the formation of chemically reactive OH and H radicals. These primary radicals either recombine leading to chemiluminescence, or diffuse into solution, where they are liable to react with other species. Of particular importance in this work is the light emission that accompanies cavitation, termed sonoluminescence (SL). This emission is a broad continuum ranging from 200nm to 900 nm, resembling the emission of a blackbody, which can be superimposed with atomic or molecular emission lines comparable to bremsstrahlung. It is necessary to distinguish two forms of SL, single-bubble (SBSL) and multibubble (MBSL). In general, MBSL spectra differ from SBSL spectra in that they contain emission lines, e.g., from alkali atoms or hydroxyl radicals [matula-1995]. Consequently, it was, until recently considered that the mechanisms of light emission, and the nature of the bubble interior upon collapse were fundamentally different for the single and multibubble systems. Considering that MBSL is a cloud of single bubbles a bridging theory is desired.With this background the objective of the present work was to conduct a comparative spectroscopic analysis of SBSL, driven at 27 kHz, and MBSL generated from low and high ultrasonic frequencies (20, 203 and 607 kHz) of aqueous electrolyte solutions. Therefore a single bubble sonoreactor was developed, where the temperature, gas content and type, as well as the acoustic pressure could be controlled. The electrolytes of choice were: sodium chloride and chlorides of the luminescent lanthanide ions, Ce3+, Tb3+, Eu3+ and Gd3+, which can be excited by UV light absorption and collisions with energetic particles [kulmala-1995]. In the first part of this work the conditions upon bubble collapse were approximated by fitting the broad-band continuum of SBSL spectra of water with 70 mbar of argon and a 0.5 M NaCl solution with 70 mbar of argon using Planck's law of blackbody radiation. The obtained blackbody temperatures are in the range of 104 K, which is in good agreement with previous studies, but with the discrepancy of being independent of the presence of NaCl and the acoustic pressure, whereas the SL intensity increased by a factor of more than 10 upon increased acoustic pressure. The different trends followed by SL intensity and blackbody temperatures question the blackbody model. Another observation questioning the blackbody model is the appearance of atomic and molecular emission lines in MBSL and as recently observed also in SBSL [liang-2007, young-2001]. The present work proofed that the key factors for line emission in SBSL are small amounts of argon and low acoustic pressure. Moreover, the work revealed that the shape of the OH• radical emission is very similar to that in MBSL spectra, indicating the strong similarity of intrabubble conditions in MBSL and SBSL under certain experimental conditions [schneider-2011]. An increase of the acoustic pressure caused the continuum to overlap the lines until they become indistinguishable giving the usually in SBSL observed featureless continuum. This advance is a big step toward bridging the gap between SBSL and MBSL. Furthermore this study reveals that the concentration of the sodium ion at the interface of a single bubble can be enriched with a surface active counterion and the concentration is crucial for the observation of the sodium line in SBSL, suggesting that excitation of sodium either takes place at the interface of the

Cette thèse présente les études de sonoluminescence multibulle (MBSL) effectuées à l’ICSM pour compléter de précédents résultats ayant mis en évidence la formation d’un plasma hors équilibre au cours de la cavitation multibulle dans l'eau. La sonoluminescence et la réactivité sonochimique de l’eau sous flux continu de mélanges gaz rare et N2 et d’une solution aqueuse d’ammoniaque sous flux continu de gaz rare sont étudiées par plusieurs techniques expérimentales. Nous avons observé, en plus de l’émission de OH (A2Σ+-X2Πi) et du continuum typique de SL, pour la première fois la sonoluminescence de NH (A3Π – X3Σ-). Les spectres de sonoluminescence, le suivi des rendements de formation des produits de la sonolyse et les résultats de fits de NH (A3Π- X3Σ-) et OH (A2Σ+-X2Πi) en utilisant le logiciel Specair confirment l’atteinte de conditions plus extrêmes au moment de l’implosion des bulles à haute fréquence ultrasonore. D’autre part, ces résultats indiquent clairement l’absence d’équilibre thermique à l’intérieur des bulles de cavitation au moment de l’implosion (Tv > Tr) quelles que soient les conditions expérimentales, et que la température vibrationnelle est plus élevée à haute fréquence US ce qui conduit au non suivi de la loi de Boltzmann des populations des niveaux vibrationnels et/ou rotationnels. En parallèle, l’évolution de la taille des bulles de cavitation a été mesurée par une technique d’ultrasons pulsés, dans le cadre d’une collaboration entre l’ICSM/LSFC et l’université de Melbourne en Australie. Nous avons en particulier mis en évidence un problème de coalescence des bulles sous flux continu de gaz, qui complique grandement l’interprétation des résultats de taille des bulles. Une autre observation est que la présence d’azote dans l’argon conduit à une diminution de la taille des bulles. / This thesis presents the studies on multibubble sonoluminescence (MBSL) performed at ICSM to complete previous results that have shown the formation of a non-equilibrium plasma in the multibubble cavitation in water. Sonoluminescence and sonochemical reactivity of water under continuous flow of noble gas and N2 mixtures and of aqueous ammonia solutions under continuous flow of noble gas are studied by several experimental techniques. In addition to OH (A2Σ+-X2Πi) band and continuum emission usually observed in the SL spectra of water in the presence of noble gases, the sonoluminescence of NH (A3Π) radicals was observed for the first time. Spectroscopy of sonoluminescence, the follow up of the sonochemical products and the spectral fits of NH (A3Π- X3Σ-) and OH (A2Σ+-X2Πi) systems using Specair software indicate more drastic conditions at high US frequency. On the other hand, NH* and OH* radicals generated inside the cavitation bubbles are far from equilibrium (Tv > Tr) whatever the experimental conditions and the vibrational temperatures at high frequency ultrasound are much higher compared to 20 kHz ultrasound which leads to strong deviation from the equilibrium (non-Boltzmann behavior). In parallel, the evolution of the bubble size is measured by a pulsed ultrasound technique, in the framework of a collaboration between ICSM / LSFC and the University of Melbourne in Australia. The problem of the coalescence of bubbles under continuous flow of gas was identified, which greatly complicates the interpretation of results of bubble size. Another interesting observation is that the presence of nitrogen in argon leads to a strong reduction in bubble size.

by Ho Yum Bun. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 93-94). / Text in English; abstracts in English and Chinese. / by Ho Yum Bun. / List of Figures --- p.3 / Abstract --- p.9 / Chinese Abstract --- p.10 / Acknowledgement --- p.11 / Chapter 1 --- Introduction --- p.12 / Chapter 1.1 --- Motivation --- p.12 / Chapter 1.2 --- What is Sonoluminescence? --- p.13 / Chapter 1.3 --- The Main Task of this Project --- p.13 / Chapter 1.4 --- Organization of this Thesis --- p.13 / Chapter 2 --- Reviews on One-dimensional Dynamical Cavity Problem --- p.15 / Chapter 2.1 --- Introduction --- p.15 / Chapter 2.2 --- Formulation --- p.15 / Chapter 2.3 --- Moore's R Function Method --- p.18 / Chapter 2.4 --- Mode Expansion Method --- p.19 / Chapter 2.5 --- Transformation method --- p.20 / Chapter 2-6 --- Summary --- p.21 / Chapter 3 --- Numerical Results For One-dimensional Dynamical Cavity Prob- lem --- p.22 / Chapter 3.1 --- Introduction --- p.22 / Chapter 3.2 --- Evolution of a Cavity System --- p.23 / Chapter 3.3 --- Motion of the Moving Mirror --- p.23 / Chapter 3.4 --- R(z) Function --- p.24 / Chapter 3.4.1 --- Construction of R(z) Function --- p.24 / Chapter 3.4.2 --- Numerical R(z) Function --- p.27 / Chapter 3.5 --- Results --- p.27 / Chapter 3.5.1 --- Results with Moore's R(z) Function Method --- p.27 / Chapter 3.5.2 --- Results with the Mode Expansion Method --- p.29 / Chapter 3.5.3 --- Results with the Transformation Method --- p.36 / Chapter 3.6 --- Summary --- p.36 / Chapter 4 --- Spherical Dynamical Cavity Problem --- p.37 / Chapter 4.1 --- Introduction --- p.37 / Chapter 4.2 --- Formulation --- p.37 / Chapter 4.3 --- Motion of a Moving Spherical Mirror --- p.39 / Chapter 4.4 --- Summary --- p.40 / Chapter 5 --- The G(z) Function Method --- p.41 / Chapter 5.1 --- Introduction --- p.41 / Chapter 5.2 --- G(z) Function --- p.42 / Chapter 5.2.1 --- Ideas of Deriving the G(z) Function --- p.42 / Chapter 5.2.2 --- Formalism --- p.42 / Chapter 5.2.3 --- Initial G(z) Function --- p.45 / Chapter 5.3 --- Construction of the G(z) Function --- p.46 / Chapter 5.3.1 --- Case I : l=0 --- p.46 / Chapter 5.3.2 --- Case II : l > 0 --- p.49 / Chapter 5.4 --- Asymptotic Series Solution of G(z) --- p.50 / Chapter 5.5 --- Application to Resonant Mirror Motion --- p.52 / Chapter 5.6 --- Regularization of G(z) --- p.58 / Chapter 5.7 --- Behaviors of the Fields --- p.58 / Chapter 5.7.1 --- z vs tf Graph --- p.61 / Chapter 5.7.2 --- Case 1: l= 0 --- p.61 / Chapter 5.7.3 --- "Case2: l= 1,2" --- p.62 / Chapter 5.7.4 --- Case 3: l= 3 --- p.73 / Chapter 5.7.5 --- Section Summary --- p.73 / Chapter 5.8 --- Summary --- p.73 / Chapter 6 --- Three-dimensional Mode Expansion Method and Transforma- tion Method --- p.75 / Chapter 6.1 --- Introduction --- p.75 / Chapter 6.2 --- Mode Expansion Method --- p.75 / Chapter 6.2.1 --- Formalism --- p.75 / Chapter 6.2.2 --- Application of Floquet's Theory --- p.78 / Chapter 6.2.3 --- Results --- p.80 / Chapter 6.3 --- The Transformation Method --- p.80 / Chapter 6.3.1 --- The Method --- p.80 / Chapter 6.3.2 --- Numerical Schemes --- p.86 / Chapter 6.3.3 --- Results --- p.89 / Chapter 6.4 --- Summary --- p.89 / Chapter 7 --- Conclusion --- p.90 / Chapter 7.1 --- The One-dimensional Dynamical Cavity Problem --- p.90 / Chapter 7.2 --- The Dynamical Spherical Cavity Problem --- p.91 / Chapter 7.3 --- Numerical Methods --- p.91 / Chapter 7.4 --- Further Investigation --- p.92 / Bibliography --- p.93

Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves 152-156).

In integrated circuit (IC) manufacturing, particulate contamination from hundreds of processe steps is a major cause of yield loss. The removal of particles is typically achieved through liquid chemical formulations aided by a sound field in the MHz frequency range. When liquid is irradiated with megasonic waves, dissolved gases play an important role in particle removal and feature damage. To take the advantage of the beneficial effect of CO₂ (aq.), this thesis describes the development and optimization of a megasonic cleaning process using a chemical system containing NH₄OH and NH₄HCO₃ at an alkaline pH in which a specific amount of aqueous CO₂ can be maintained to minimize feature damage. In addition, certain etching effects at a slightly alkaline pH were supported for achieving high particle removal. Sonoluminescence (SL) data were collected from these cleaning solutions and correlated with the cleaning performance. The intensity of SL is believed to be a sensitive indicator of transient cavitation during megasonic irradiation, which is thought to be responsible for fragile feature damage. To further analyze the SL signal with respect to the emission from hydroxyl radicals, single-band filters were used to collect the SL signal in different wavelength ranges. The study of particle removal and feature damage was performed using a single-wafer cleaning tool, MegPie® (ProSys, Inc.), which provided acoustic irradiation at a frequency of 0.925 MHz. Commercially available SiO₂ slurry with 200 ± 20 nm particles was used for particle contamination. Particle removal was investigated on both blanket SiO₂ samples and patterned samples. Feature damage studies were conducted on patterned samples by examining the number of line breakages per unit area. By adjusting the pH in NH₄OH/NH₄HCO₃ solutions from 7.8 to 8.5, the amount of CO₂ (aq.) was varied. At a pH of 8.2 with ~ 320 ppm CO₂ (aq.) in the cleaning solution, a high particle removal efficiency was achieved (> 90%) at an acoustic power intensity of 1 W/cm² for an exposure time of 60 s, and the feature damage was reduced by > 50%. For SL signal analysis, band filters in the wavelength range of (i) 280 – 305.5 nm, (ii) 300 – 340 nm, (iii) 335 – 375 nm, and (iv) 374.5 – 397.5 nm were used to resolve the SL spectrum in these wavelength ranges. The filters were sandwiched, one at a time, between the optical window and the photomultiplier tube (PMT) in the Cavitation Threshold (CT) cell. Air-, Ar-, and CO₂-containing DI water (at pH 4.53 with ~ 90 ppm aqueous CO₂) was pumped through the cell at a flow rate of 130 ml/min. The acoustic power was ramped from 0.1 to 4 W/cm² at an acoustic frequency of 0.925 MHz. The SL signal intensity showed the highest value in the ranges of 300 – 340 and 335 – 375 nm in air- and Ar-saturated DI water, which is due to the emission from excited hydroxyl radicals. These results are consistent with an SL spectrum analysis performed using expensive optical set-ups. In CO₂-containing DI water, the SL signal intensity was suppressed by a factor of 100. The methodology reported in this work is simple, inexpensive, and capable of capturing SL spectral features due to hydroxyl radicals.

No description available.

Ng, Siu Fai = 溫暖稠密物質及高能量密度物理的研究 / 吳肇輝. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 126-133). / Abstracts also in Chinese. / Ng, Siu Fai = Wen nuan chou mi wu zhi ji gao neng liang mi du wu li de yan jiu / Wu Zhaohui. / Chapter 1 --- Introduction --- p.16 / Chapter 1.1 --- General review of high energy density physics --- p.16 / Chapter 1.2 --- General review of warm dense matter --- p.20 / Chapter 1.2.1 --- Physics of warm dense matter --- p.20 / Chapter 1.2.2 --- Uncertainties of warm dense matter --- p.23 / Chapter 1.2.3 --- Challenges of warm dense matter studies --- p.25 / Chapter 1.3 --- Use of intense heavy ion beam --- p.27 / Chapter 1.4 --- Motivation and structure of this thesis --- p.32 / Chapter 2 --- Hydrodynamic simulations --- p.34 / Chapter 2.1 --- Lagrangian hydrodynamic code --- p.34 / Chapter 2.2 --- Hydrodynamic equations --- p.35 / Chapter 2.3 --- Artificial viscosity --- p.36 / Chapter 3 --- Equations of state --- p.38 / Chapter 3.1 --- Van der Waals' equation of state --- p.39 / Chapter 3.2 --- Quotidian equation of state --- p.41 / Chapter 3.3 --- Saha-based equation of state --- p.41 / Chapter 3.4 --- Inverse power potentials equation of state --- p.48 / Chapter 3.5 --- Gruneisen-type equation of state --- p.53 / Chapter 3.6 --- Discussion --- p.59 / Chapter 4 --- Single bubble sonoluminescence --- p.63 / Chapter 4.1 --- Introduction --- p.63 / Chapter 4.2 --- Theory of sonoluminescence --- p.65 / Chapter 4.2.1 --- Bubble wall dynamics --- p.66 / Chapter 4.2.2 --- Radiation transport --- p.67 / Chapter 4.2.3 --- Diffusive stability --- p.68 / Chapter 4.3 --- Numerical simulation --- p.68 / Chapter 4.3.1 --- Determination of the ambient radius --- p.69 / Chapter 4.3.2 --- Simulations using SEOS --- p.70 / Chapter 4.3.3 --- Simulations using QEOS --- p.77 / Chapter 4.4 --- Conclusion --- p.82 / Chapter 5 --- Collapsing bubble in ion-beam-heated metal --- p.83 / Chapter 5.1 --- Introduction --- p.83 / Chapter 5.2 --- Bubble collapse --- p.86 / Chapter 5.2.1 --- First step of collapse --- p.88 / Chapter 5.2.2 --- Stagnation point and bubble size --- p.89 / Chapter 5.2.3 --- Outer boundary and metal thickness --- p.91 / Chapter 5.2.4 --- Metal layer just outside bubble --- p.93 / Chapter 5.3 --- Effect of equation of state used --- p.95 / Chapter 5.3.1 --- Inverse power potentials equation of state --- p.95 / Chapter 5.3.2 --- Effect of ionization --- p.97 / Chapter 5.3.3 --- Effect of hard core --- p.97 / Chapter 5.3.4 --- Effect of EOS for metal --- p.97 / Chapter 5.4 --- Effect of proposed experimental parameters --- p.102 / Chapter 5.4.1 --- Initial gas density --- p.102 / Chapter 5.4.2 --- Energy deposition rate --- p.102 / Chapter 5.5 --- Conclusion and discussion --- p.105 / Chapter 6 --- High coupling efficiency compression by intense ion beams --- p.108 / Chapter 6.1 --- Introduction --- p.108 / Chapter 6.2 --- Ion stopping formulation --- p.111 / Chapter 6.3 --- Numerical simulation --- p.112 / Chapter 6.3.1 --- Lithium hydride target --- p.112 / Chapter 6.3.2 --- Underdense aluminum foam --- p.118 / Chapter 6.4 --- Conclusion --- p.119 / Chapter 7 --- Conclusion --- p.121 / Chapter 7.1 --- Summary --- p.121 / Chapter 7.2 --- Suggestions for future work --- p.123 / Bibliography --- p.126

The dissolution of quantum sized CdS and MnO2 particles in water was conducted using 20 kHz ultrasound. CdS particles were found to dissolve chemically via an oxidation process while MnO2 particles dissolved via a reductive process. It was found that the dissolution of the colloids could be controlled via the addition of surface active chemicals to solution and by varying the saturation gas type. In the presence of Na2S or propan-2-ol and argon gas, the dissolution of CdS was inhibited, whereas the addition of alcohols (methanol, ethanol, propan-2-ol, butan-1-ol and pentan-1-ol) to the MnO2 system led to an increase in the amount of dissolution for a given time of sonication. This increase in dissolution was found to be dependent on the ability of the surface active radical scavenger to accumulate around the bubble interface during the cavitation process. Eventually, at higher alcohol concentration there was a plateau or a limiting value reached for the efficiency of colloid dissolution which was common for each alcohol. (For complete abstract open document)