High-extinction-ratio resonant cavity polarizer for quantum-optics measurements

The use of a high-finesse Fabry-Perot ring cavity with an odd number of reflections as a high-extinction-ratio resonant polarizer is shown. Experimental results from quantum-noise measurements using resonant cavities as spatial and spectral filters and precision polarizers are presented

Oxidative Carbon-Carbon Bond Cleavage Reactions of Metal Flavonolato and Chlorodiketonate Complexes

The research presented in this dissertation has focused on studies of metal complexes which undergo oxidative aliphatic carbon-carbon bond cleavage using dioxygen as the oxidant. The goal of this research was to assess the reactivity and elucidate mechanistic details of the carbon-carbon bond cleavage reactions. The first part of this dissertation explores the light-induced dioxygenase reactivity of ruthenium flavonolato compounds. These compounds are of particular interest as they are currently being explored for their anti-cancer activity. The RuII(n6-p-cymene) flavonolato compounds studied were found to undergo photoinduced carbon-carbon bond cleavage albeit with low quantum efficiency. The cleaved products were found to be significantly less toxic than the starting material. The reactivity and loss of toxicity offers the possibility of light-induced deactivation of such compounds to limit overall toxicity. The remainder of the research presented in this dissertation is directed at understanding mechanistic features that govern the aliphatic carbon-carbon bond cleavage reactivity of mononuclear copper(II) chlorodiketonate complexes. Synthetic organic chemists have utilized molecular oxygen and copper catalysts for many organic transformations. However, few reports have appeared demonstrating aliphatic carbon-carbon bond cleavage mediated by copper and O2 and mechanistic details of these processes are limited. The previously reported complex [(6-Ph2TPA)Cu(PhC(O)CClC(O)Ph)]ClO4 was found to undergo aliphatic carbon-carbon bond cleavage under ambient conditions in the presence of O2. Notably, a catalytic amount of chloride anion increases the rate of this reaction. In order to understand this enhanced reactivity, we have performed mechanistic experiments to probe this system. These include: (1) spectroscopic studies to probe anion binding to the copper center; (2) variable temperature kinetic studies to benchmark computational studies; and (3) evaluation of the impact of electron density within the chlorodiketonate substrate on the rate of the reaction. The nature of the anion in the [(6-Ph2TPA)Cu(PhC(O)CClC(O)Ph)]ClO4 system was found to play a significant role in terms of the energy barriers associated with O2 activation and O-O bond cleavage. The electronic nature of the chlorodiketonate was found to affect the kinetics for the C-C bond cleavage reaction suggesting a change in mechanism for O2 activation depending on the substituent present

Design and construction of a point-contact spectroscopy rig with lateral scanning capability

The design and realization of a cryogenic rig for point-contact spectroscopy measurements in the needle-anvil configuration is presented. Thanks to the use of two piezoelectric nano-positioners, the tip can move along the vertical ($z$) and horizontal ($x$) direction and thus the rig is suitable to probe different regions of a sample \textit{in situ}. Moreover, it can also form double point-contacts on different facets of a single crystal for achieving, e.g., an interferometer configuration for phase-sensitive measurements. For the latter purpose, the sample holder can also host a Helmholtz coil for applying a small transverse magnetic field to the junction. A semi-rigid coaxial cable can be easily added for studying the behavior of Josephson junctions under microwave irradiation. The rig can be detached from the probe and thus used with different cryostats. The performance of this new probe has been tested in a Quantum Design PPMS system by conducting point-contact Andreev reflection measurements on Nb thin films over large areas as a function of temperature and magnetic field.Comment: 7 pages, 7 figures, published in Rev. Sci. Instru

Method for fabricating zig-zag slabs for solid state lasers

A method for batch manufacturing of slabs for zig-zag lasers including steps of bonding two non-active media to either side of an active medium to form a sandwich, dicing the sandwich to provide slices, rendering two surfaces of each slice into total-internal-reflection (TIR) surfaces, and then dicing the slices perpendicular to the TIR surfaces to provide a plurality of zig-zag slabs

Production of Intermediate or Medium Carbon Ferro Chrome at FACOR

FACOR has foreseen the need to develop the intermediate carbon ferro chrome alloy to meet the demands of alloy and stainless steel manufacturers.The paper describes the decarbonisation of liquid high carbon ferro chrome in. an AOD convertor with respect to : (a) Theoretical aspects and fundamentals, (b) Plant and equipment, (c) Process of making intermediate carbon ferro chromium., (d) Advantages of the processto improve the quality with respect to titanium, silicon, hydrogen and nitrogen in intermediate carbon ferro chromium

Synthesis and Characterization of Pure and Doped Ceria Films by Sol-Gel and Sputtering

Pure and doped Ceria are known for their ability to gain or lose Oxygen, which is of interest to the Solid Oxide Fuel Cell (SOFC) and catalyst community. Current efforts are focused in SOFCs to reduce the operating temperature of the cell while maintaining ionic conduction. Ceria is known for its high ionic conductivity in the intermediate temperature region. (600-800° C) We have prepared pure and doped Ceria films by Sol-gel and magnetron sputtering methods. Enhanced grain-boundary contribution in the conductivity can be studied in the Sol-gel process due to excellent control over the synthesis conditions, which enabled us to control the average grain size. Sputtered films were grown and investigated as a prelude to possible multi-layered CeO2 structures in the near future. These films were characterized by X-ray diffraction (XRD), nuclear reaction analysis (NRA), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and Oxygen conduction measurements. We have observed greater volume diffusion in nanocrystalline Ceria compared to bulk polycrystalline films as a result of low density. Near surface diffusion properties with increasing temperature indicate a decrease in the volume diffusion as a result of grain growth. However, a linear increase in O2 content at ~600nm depth was observed and can be correlated to the redistribution of O2 in the samples. Surface roughness of and oriented Ceria films on Al2O3 and YSZ was observed to be 0.13nm and 0.397nm, respectively. In the case of Ceria grown on YSZ, structural properties from XRD results showed a highly oriented structure with cube on cube growth. XRD results from Ceria grown on Al2O3 showed an oriented structure whose degree of orientation appeared to be partially dependent on substrate temperature. Preliminary XPS results indicate reduction in Ceria from the Ce4+ to Ce3+ state near the surface