The authors measure the time-dependent CP asymmetry parameters in B{sup 0} {yields} K{sup +}K{sup -}K{sup 0} based on a data sample of approximately 277 million B-meson pairs recorded at the {Upsilon}(4S) resonance with the BABAR detector at the PEP-II B-meson Factory at SLAC. They reconstruct two-body B{sup 0} decays to {phi}(1020)K{sub s}{sup 0} and {phi}(1020)K{sub L}{sup 0}. Using a time-dependent maximum-likelihood fit, they measure sin2{beta}{sub eff}({phi}K{sup 0}) = 0.48 {+-} 0.28 {+-} 0.10, and C({phi}K{sup 0}) = 0.16 {+-} 0.25 {+-} 0.09, where the first error is statistical, and the second is systematic. They also present measurements of the CP-violating asymmetries in the decay B{sup 0} {yields} f{sub 0}({yields} {pi}{sup +}{pi}{sup -})K{sub s}{sup 0}. The results are obtained from a data sample of 209 x 10{sup 6} {Upsilon}(4S) {yields} B{bar B} decays, also collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. From a time-dependent maximum-likelihood fit they measure the mixing-induced CP violation parameter S(f{sub 0}(980)K{sub S}{sup 0}) = - sin 2{beta}{sub eff}f{sub 0}(980)K{sub S}{sup 0} = -0.95{sub -0.23}{sup +0.32} {+-} 0.10 and the direct CP violation parameter C(f{sub 0}(980)K{sub S}{sup 0}) = - 0.24 {+-} 0.31 {+-} 0.15, where the first errors are statistical and …

Despite more than thirty years having elapsed since the discovery of CP violation, our understanding about the source and the nature of this phenomenon is still very limited. In the standard model of particle physics, CP violation is due to the presence of an non-irreducible weak phase in the Cabibbo-Kabayashi-Maskawa(CKM) matrix. Up to now, all the experimental results are in good agreement with the standard model. However, it is important for us to over-constrain the CKM quark-mixing matrix and explore the possibility of new physics beyond the standard model. The B meson provides an ideal place to measure CP violation due to its heavy mass and potentially large CP-violating effects. In particular, the angle {gamma} of the Unitary Triangle relating the elements of the CKM matrix is extremely crucial in terms of CP violation and constraints on the new physics models. Various methods using B{sup -} {yields} D{sup 0}K{sup -} decays have been proposed to measure based on the interference between the V{sub cb} and V{sub ub} amplitudes. Despite the simple concept, the measurement turns out to be experimentally challenging due to the small branching fraction and the small value of {tau}{sub B}, the amplitude ratio between the two contributing …

The relation of structure to lack of superconductivity in Pr-Ba-Cu-O was systematically investigated. First, the phase equilibria of this system was studied to find the processing parameters which maximize the cation-site ordering between Pr and Ba ions. Second, a comparative study between superconducting Nd-Ba-Cu-0 and non- superconducting Pr-Ba-Cu-0 was performed by forming solid-solution Nd- Pr-Ba-Cu-0. The relation between structure and superconductivity in Nd{sub 1{minus}x}Pr{sub x}Ba{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} is investigated. {Tc} decreases monotonically with increasing {times} and superconductivity disappears at around x=0.3-0.4. {Tc} is enhanced by 10K when the sample is processed at an oxygen partial pressure (PO{sub 2}) of 0.01 atm, followed by oxygenation at 450C. Depression of {Tc} as a function of {times} and PO {sub 2} is explained in terms of a charge-transfer model. It is suggested that destruction of superconductivity in the RE{sub 1{minus}x}Pr{sub x}Ba{sub 2}CU{sub 3}O{sub 7{minus}{delta}} (RE=rare-earth) system can be viewed as disruption of four-fold planar coordinated Cu ions in the chain-site due to permanent occupation of extra Pr ions on Ba sites.

Kinetic data for elimination of silylene supports formation of a ``tighter`` transition state, indicating a silacyclopropene intermediate. This extends the silacyclopropene mechanism to the cyclicdialkyne system and validates the consistency of the mechanism for silylakynes, in general. Investigation into the other possible silacyclopropene product established the instability of the product. The work with silylketenes proved that an inherent difference exists between reactivity of monosilyl-substituted ketenes and polysilyl-substituted ketenes. Although the mechanism for thermal decomposition of bis(silyl)ketenes can be modified to account for the unexpected silylene elimination products, reasons for the difference are limited to speculation. The photochemistry of silylketenes has not been previously studied, so a model system does not exist for comparison with our polysilylketene work. The photochemical experimentation suggests that the photochemistry and thermochemistry of polysilylketenes is not the same. A more extensive study of the mechanism of the systems covered in this research as well as with monosilyl-substituted systems is needed.

Mechanisms and associated energetics for adatom diffusion on the (100) and (110) surfaces of Ni, Cu, Rh, Pd, and Ag are investigated. Self-diffusion was studied on (100) and (I 10) surfaces of Ni, Cu, Pd and Ag using corrected effective medium method (CEM) and approximation to CEM used for molecular dynamics and Monte Carlo studies (MD/MC-CEM). Self-diffusion on Pd(100), Ag(100), Ni(110), Cu(110), Pd(110), and Ag(110) is accomplished by classical diffusion: the adatom hops from its equilibrium adsorption site over an intervening bridge site to an adjacent equilibrium site. Self-diffusion on Ni(100) and Cu(100) proceeds by atomic-exchange diffusion: the adatom on the surface displaces an atom in the first surface layer. Aside from explicit inclusion of the kinetic-exchange-correlation energy, it is critical to include enough movable atoms in the calculation to insure correct energetics. Distortions induced by these diffusion mechanisms, especially atomic exchange, are long ranged in surface plane, owing to small distortions of many atoms being energetically favored over large distortions of few atoms. Energetics and rates of heterogeneous adatom diffusion on the (100) surfaces of Ni, Cu, Rh, Pd, and Ag show that the final state energies differ due to variation of metallic bonding with coordination for different types …

Role of H spillover to the silica support was studied using chemisorption; a strongly bound component of spilled over H was found in the silica support which interfered with accurate measurements of active metal sites via volumetric strong H chemisorption. The volumetric chemisorption technique was modified so that measurement times were reduced from 12--36 h to 1 h. The active Ru surface was characterized means of changes in proton spin counts and NMR Knight shifts vs alkali loading. Na, K blocked the active surface of Ru metal, but Cs was pushed off by H chemisorption. The alkali promoters restricted H mobility on both metal surface and at the metal support interfaces; this is consistent with effects on Fischer-Tropsch synthesis. {sup 1}H NMR was used to study the effect of the active metal and promoter on support hydroxyl groups. The OH group density in the silica support decreased with metal and/or promoter loading, but not on a one-to-one basis; the exchange efficiency of the hydroxyls decreased with atomic size of the alkali metal. An additional downfield proton resonance was detected which was assigned to the alkali hydroxide species in the support.

Millions of people suffering from diseases such as retinitis pigmentosa and macular degeneration are legally blind due to the loss of photoreceptor function. Fortunately a large percentage of the neural cells connected to the photoreceptors remain viable, and electrical stimulation of these cells has been shown to result in visual perception. These findings have generated worldwide efforts to develop a retinal prosthesis device, with the hope of restoring vision. Advances in microfabrication, integrated circuits, and wireless technologies provide the means to reach this challenging goal. This dissertation describes the development of innovative silicone-based microfabrication techniques for producing an implantable microelectrode array. The microelectrode array is a component of an epiretinal prosthesis being developed by a multi-laboratory consortium. This array will serve as the interface between an electronic imaging system and the human eye, directly stimulating retinal neurons via thin film conducting traces. Because the array is intended as a long-term implant, vital biological and physical design requirements must be met. A retinal implant poses difficult engineering challenges due to the size of the intraocular cavity and the delicate retina. Not only does it have to be biocompatible in terms of cytotoxicity and degradation, but it also has to be structurally …

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Scene reconstruction from video sequences has become a prominent computer vision research area in recent years, due to its large number of applications in fields such as security, robotics and virtual reality. Despite recent progress in this field, there are still a number of issues that manifest as incomplete, incorrect or computationally-expensive reconstructions. The engine behind achieving reconstruction is the matching of features between images, where common conditions such as occlusions, lighting changes and texture-less regions can all affect matching accuracy. Subsequent processes that rely on matching accuracy, such as camera parameter estimation, structure computation and non-linear parameter optimization, are also vulnerable to additional sources of error, such as degeneracies and mathematical instability. Detection and correction of errors, along with robustness in parameter solvers, are a must in order to achieve a very accurate final scene reconstruction. However, error detection is in general difficult due to the lack of ground-truth information about the given scene, such as the absolute position of scene points or GPS/IMU coordinates for the camera(s) viewing the scene. In this dissertation, methods are presented for the detection, factorization and correction of error sources present in all stages of a scene reconstruction pipeline from video, in the …

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This dissertation describes a measurement of the rate ofnuclear muon capture by the proton, performed by the MuCap Collaborationusing a new technique based on a time projection chamber operating inultraclean, deuterium-depleted hydrogen gas at room temperature and 1 MPapressure. The hydrogen target's low gas density of 1 percent compared toliquid hydrogen is key to avoiding uncertainties that arise from theformation of muonic molecules. The capture rate was obtained from thedifference between the mu- disappearance rate in hydrogen--as determinedfrom data collected in the experiment's first physics run in fall2004--and the world averagefor the mu+ decay rate. After combining theresults of my analysis with the results from another independent analysisof the 2004 data, the muon capture rate from the hyperfine singlet groundstate of the mu-p atom is found to be Lambda_S = 725.0 +- 17.4 1/s, fromwhich the induced pseudoscalar coupling of the nucleon, gP(q2 = -0.88m2mu)= 7.3 +- 1.1, is extracted. This result for gP is consistent withtheoretical predictions that are based on the approximate chiral symmetryof QCD.

Over the last few years, the B factories have established the Cabbibo-Kobayashi-Maskawa mechanism of CP violation in the Standard Model through the study of the decays of B mesons. The focus of Belle and BaBar has now expanded to the search for signatures of new physics beyond the Standard Model, particularly through examination of flavor-changing neutral-current transitions, which proceed through diagrams involving virtual loops. These decays are suppressed in the Standard Model, increasing sensitivity to new-physics effects but decreasing branching fractions. Exploiting large and growing datasets, BaBar and Belle have made many measurements in loop decays where a b quark transitions to an s quark, observing hints of possible deviations from Standard Model expectations in CP-violating measurements.

A sample of 2500 {Xi}{sup -} and 500 {Xi}{sup 0} hyperons, produced in {Xi}K, {Xi}K{pi}, and {Xi}K{pi}{pi} final states by K{sup -} (in H{sub 2}) at incident momenta of 1.7 to 2.7 BeV/c, has been analyzed. The data are from an exposure (K-63) of 26 events/{mu}b in the 72-inch bubble chamber; approximately 85% of the {Xi}{sup -} events and 60% of the {Xi}{sup 0} events have been analyzed. For the {Xi}, they determine the spin and decay parameters a{sub {Xi}} and {Phi}{sub {Xi}} = tan{sup -1} ({beta}{sub {Xi}}/{Gamma}{sub {Xi}}). Combining their data with 900 {Xi}{sup -} and 150 {Xi}{sup 0} events from an earlier experiment (K-72), they obtain the following results: (1) {Xi} spin - J = 1/2 favored over J = 3/2 by {approx} 2.5 standard deviations; (2) {Xi} decay parameters (assuming a{sub {Lambda}} = 0.647 {+-} 0.048) - a{sub {Xi}{sup -}} = -0.398 {+-} 0.041, {Phi}{sub {Xi}{sup -}} = 9.8{sup o} {+-} 9.0{sup o}; a{sub {Xi}{sup 0}} = -0.413 {+-} 0.104. They observe {Xi}*(1530) and {Xi}*(1817); their data are insufficient for analysis of suggested {Xi}* resonances at 1705 and 1933 MeV. They measure the {Xi}*(1530) electromagnetic mass difference {Delta}m = m({Xi}*{sup -}) = m({Xi}*{sup 0}) = 2.0 {+-} …

We have presented results in two different yet strongly linked aspects of Higgs boson physics. We have learned about the importance of the Higgs boson for the fate of the Standard Model, being either only a theory limited to explaining phenomena at the electroweak scale or, if the Higgs boson lies within a mass range of 130 < m_H < 160 GeV the SM would remain a self consistent theory up to highest energy scales O(m_Pl). This could have direct implications on theories of cosmological inflation using the Higgs boson as the particle giving rise to inflation in the very early Universe, if it couples non-minimally to gravity, an effect that would only become significant at very high energies. After understanding the immense meaning of proving whether the Higgs boson exists and if so, at which mass, we have presented a direct search for a Higgs boson in associated production with a W boson in a mass range 100 < m_H < 150 GeV. A light Higgs boson is favored regarding constraints from electroweak precision measurements. As a single analysis is not yet sensitive for an observation of the Higgs boson using 5.3 fb^-1 of Tevatron data, we set limits …

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The Sudbury Neutrino Observatory (SNO) is a large-volume heavy water Cerenkov detector designed to resolve the solar neutrino problem. SNO observes charged-current interactions with electron neutrinos, neutral-current interactions with all active neutrinos, and elastic-scattering interactions primarily with electron neutrinos with some sensitivity to other flavors. This dissertation presents an analysis of the solar neutrino flux observed in SNO in the second phase of operation, while {approx}2 tonnes of salt (NaCl) were dissolved in the heavy water. The dataset here represents 391 live days of data. Only the events above a visible energy threshold of 5.5 MeV and inside a fiducial volume within 550 cm of the center of the detector are studied. The neutrino flux observed via the charged-current interaction is [1.71 {+-} 0.065(stat.){+-}{sub 0.068}{sup 0.065}(sys.){+-}0.02(theor.)] x 10{sup 6}cm{sup -2}s{sup -1}, via the elastic-scattering interaction is [2.21{+-}0.22(stat.){+-}{sub 0.12}{sup 0.11}(sys.){+-}0.01(theor.)] x 10{sup 6}cm{sup -2}s{sup -1}, and via the neutral-current interaction is [5.05{+-}0.23(stat.){+-}{sub 0.37}{sup 0.31}(sys.){+-}0.06(theor.)] x 10{sup 6}cm{sup -2}s{sup -1}. The electron-only flux seen via the charged-current interaction is more than 7{sigma} below the total active flux seen via the neutral-current interaction, providing strong evidence that neutrinos are undergoing flavor transformation as they travel from the core of the Sun to the …

A variety of scenarios are considered which shed light upon the uses and limitations of classical geometric and topological notions in string theory. The primary focus is on situations in which D-brane or string probes of a given classical space-time see the geometry quite differently than one might naively expect. In particular, situations in which extra dimensions, non-commutative geometries as well as other non-local structures emerge are explored in detail. Further, a preliminary exploration of such issues in Lorentzian space-times with non-trivial causal structures within string theory is initiated.

Protein phosphorylation is a general mechanism for signal transduction as well as regulation of cellular function. Unlike phosphorylation in eukaryotic systems that uses Ser/Thr for the sites of modification, two-component signal transduction systems, which are prevalent in bacteria, archea, and lower eukaryotes, use an aspartate as the site of phosphorylation. Two-component systems comprise a histidine kinase and a receiver domain. The conformational change of the receiver domain upon phosphorylation leads to signal transfer to the downstream target, a process that had not been understood well at the molecular level. The transient nature of the phospho-Asp bond had made structural studies difficult. The discovery of an excellent analogue for acylphosphate, BeF{sub 3}{sup -}, enabled structural study of activated receiver domains. The structure of activated Chemotaxis protein Y (CheY) was determined both by NMR spectroscopy and X-ray crystallography. These structures revealed the molecular basis of the conformational change that is coupled to phosphorylation. Phosphorylation of the conserved Asp residue in the active site allows hydrogen bonding of the T87 O{gamma} to phospho-aspartate, which in turn leads to the rotation of Y106 into the ''in'' position (termed Y-T coupling). The structure of activated CheY complexed with the 16 N-terminal residues of FliM (N16-FliM), …

As the dimensions of semiconductor devices are scaled down, in order to achieve higher levels of integration, optical lithography will no longer be sufficient for the needs of the semiconductor industry. Alternative next-generation lithography (NGL) approaches, such as extreme ultra-violet (EUV), X-ray, electron-beam, and ion projection lithography face some challenging issues with complicated mask technology and low throughput. Among the four major alternative NGL approaches, ion beam lithography is the only one that can provide both maskless and resistless patterning. As such, it can potentially make nano-fabrication much simpler. This thesis investigates a focused ion beam system for maskless, resistless patterning that can be made practical for high-volume production. In order to achieve maskless, resistless patterning, the ion source must be able to produce a variety of ion species. The compact FIB system being developed uses a multicusp plasma ion source, which can generate ion beams of various elements, such as O{sub 2}{sup +}, BF{sub 2}{sup +}, P{sup +} etc., for surface modification and doping applications. With optimized source condition, around 85% of BF{sub 2}{sup +}, over 90% of O{sub 2}{sup +} and P{sup +} have been achieved. The brightness of the multicusp-plasma ion source is a key issue for …

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The safety and optimal performance of large, commercial, light-water reactors require the knowledge at all time of the neutron-flux distribution in the core. In principle, this information can be obtained by solving the time-dependent neutron diffusion equations. However, this approach is complicated and very expensive. Sufficiently accurate, real-time calculations (time scale of approximately one second) are not yet possible on desktop computers, even with fast-running, nodal kinetics codes. A semi-experimental, nodal synthesis method which avoids the solution of the time-dependent, neutron diffusion equations is described. The essential idea of this method is to approximate instantaneous nodal group-fluxes by a linear combination of K, precomputed, three-dimensional, static expansion-functions. The time-dependent coefficients of the combination are found from the requirement that the reconstructed flux-distribution agree in a least-squares sense with the readings of J ({ge}K) fixed, prompt-responding neutron-detectors. Possible numerical difficulties with the least-squares solution of the ill-conditioned, J-by-K system of equations are brought under complete control by the use of a singular-value-decomposition technique. This procedure amounts to the rearrangement of the original, linear combination of K expansion functions into an equivalent more convenient, linear combination of R ({le}K) orthogonalized ``modes`` of decreasing magnitude. Exceedingly small modes are zeroed to eliminate any …

The Retinal Prosthesis project is a three year project conducted in part at the Lawrence Livermore National Laboratory and funded by the Department of Energy to create an epiretinal microelectrode array for stimulating retinal cells. The implant must be flexible to conform to the retina, robust to sustain handling during fabrication and implantation, and biocompatible to withstand physiological conditions within the eye. Using poly(dimethyl siloxane) (PDMS), LLNL aims to use microfabrication techniques to increase the number of electrodes and integrate electronics. After the initial designs were fabricated and tested in acute implantation, it became obvious that there was a need to characterize and understand the mechanical and electrical properties of these new structures. This knowledge would be imperative in gaining credibility for polymer microfabrication and optimizing the designs. Thin composite microfabricated devices are challenging to characterize because they are difficult to handle, and exhibit non-linear, viscoelastic, and anisotropic properties. The objective of this research is to device experiments and protocols, develop an analytical model to represent the composite behavior, design and fabricate test structures, and conduct experimental testing to determine the mechanical and electrical properties of PDMS-metal composites. Previous uniaxial stretch tests show an average of 7% strain before failure …

High temperature alloys are reviewed, focusing on current superalloys and their coatings. The synthesis, characerization, and oxidation performance of a NiAl–TiB{sub 2} composite are explained. A novel coating process for Mo–Ni–Al alloys for improved oxidation performance is examined. The cyclic oxidation performance of coated and uncoated Mo–Ni–Al alloys is discussed.