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Detection of unstable intermediates and mechanistic studies in multisteps, two-electron transfer reactions by cyclic voltammetry and scanning electrochemical microscopyChang, Jinho 01 September 2015 (has links)
Unstable Sn(III) intermediates generated in the Sn(IV)/Sn(II) redox reaction in 2 M HBr + 4 M NaBr media were detected by scanning electrochemical microscopy (SECM) and cyclic voltammetry (CV). In CV, the underpotential deposition of Sn(0) and its stripping peaks severely perturbed the analysis of diffusional reactions. In SECM, however, the detection of diffusional Sn(III) bromide species was clearly observed due to the absence of the perturbation from the surface reactions. The ECEC-DISP mechanism in both the reduction and oxidation reactions was proposed via Sn(III) bromide intermediates. CVs at different concentrations of Sn(IV) and at various scan rates were fit by numerical simulations based on the proposed mechanism with good agreement. Enhanced electrochemical reversibility in the Sn(IV)/Sn(II) redox reaction was observed at the elevated temperature of 80 °C. We attributed such observation to changes in the rate of bromide loss from Sn(IV)Br₆²⁻ to Sn(IV)Br₅⁻ based on the CV simulation. In a similar approach, a short-lived intermediate, presumably bromine anion radical Br₂⁻·, was detected in the Br⁻ /Br₃⁻ electro-oxidation reaction in nitrobenzene solution by SECM and CV. The reaction mechanism was proposed based on a detected Br₂⁻· intermediate as follows: (1) the one electron transfer of Br⁻ to Br·, (2) the dimerization of 2Br· to Br₂, (3) the bromide addition reaction of Br₂ to Br₃⁻ , (4) the bromide addition reaction of Br· to Br₂⁻·, and (5) the Br· addition reaction of Br₂⁻· to Br₃⁻. The simulation based on the proposed mechanism fitted well with the experimental SECM and CV results. At last, the applicability of the Sn/Br system as electrolyte for electrochemical energy storage was tested. A redox flow battery was constructed, where the Sn(IV)/Sn(II) reduction was carried out on the negative electrode, while the Br· /Br₂ oxidation was carried out on the positive electrode during charging. Cyclability was tested up to 35 charge/discharge cycles, and 100 % coulombic efficiency was observed in all cycles. However, only 40 % of voltage efficiency was obtained, mainly due to the large irreversibility of the Sn(IV)/Sn(II) redox reaction in the bromide media.
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Hybrid Sn/Diffusion and Sn/P3 Neutronics CalculationsManolov, Sergiy 02 October 2013 (has links)
In this thesis we investigate coupling and preconditioning techniques for 19D hybrid neutronics calculations. Each problem is represented by two spatial regions with Sn in one region and either Diffusion (P1) or P3 in the other region. For each of these two cases we define one coupling scheme and two different preconditioned systems. These systems are solved with both fixed9point iteration and the GMRES Krylov method. The solution techniques are compared in terms of iteration count and computational cost. Preconditioning with a global diffusion operator is found to be very effective for the most difficult problems.
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Um Estudo Sobre Verbo Suporte na Construção de Dar + SnDAVEL, A. P. C. 07 March 2009 (has links)
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Previous issue date: 2009-03-07 / Esta dissertação tem como objetivo apresentar um estudo sobre as estruturas com verbosuporte DAR+SN no português do Brasil, a partir da Teoria Lexical e dos princípios do Léxico-Gramática. São examinadas as propriedades distribucionais dessa estrutura, em contextos de uso da língua, por meio de critérios formais que levam em conta os aspectos morfossintáticosemânticos, distinguindo-se a estrutura com verbo pleno de verbo suporte e de expressões cristalizadas. As estruturas com verbo suporte são de natureza denominal e deverbal. De modo geral, as denominais denotam ações de golpe como, por exemplo, dar uma pedrada e as deverbais apresentam atenuação e brevidade das ações como, por exemplo, dar uma olhada. Os estudos revelam que as estruturas DAR uma X-ada são também utilizadas como formas modalizadoras da linguagem, constituindo um recurso de expressividade por parte dos falantes nativos.
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Nucleosynthesis Constraints on the Energy Growth Timescale of a Core-collapse Supernova Explosion / 重力崩壊型超新星の爆発タイムスケールについて 元素合成からの制約Sawada, Ryo 23 March 2020 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第22249号 / 理博第4563号 / 新制||理||1655(附属図書館) / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)准教授 前田 啓一, 講師 LEE Shiu Hang, 教授 長田 哲也 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM
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Development of Advanced Numerical Methods for Solving Neutron Transport Problems: DG-DSA and the Shishkin Mesh for Problems with Sharp LayersByambaakhuu, Tseelmaa 01 October 2021 (has links)
No description available.
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Elektronické a adsorpční vlastnosti modelových katalyzátorů s obsahem céru / Electronics and adsorption properties of model catalytic systems contains ceriumCabala, Miloš January 2014 (has links)
Title: Electronics and adsorption properties of model catalytic systems contains cerium Author: Miloš Cabala Department: Department of Surface and Plasma Science, Supervisor: RNDr. Kateřina Veltruská, Department of Surface and Plasma Science, Abstract: The doctoral thesis contains the study of model catalyst systems based on cerium and ceria. The thesis deals with model systems of CeAg, CeO2/Cu(111), Ni- CeO2/Cu(111) a Ni-Sn-CeO2/Cu(111). We have studied these systems using photoelectron spectroscopy, ion scattering spectroscopy and low energy electron diffraction. Model systems were prepared under strictly defined conditions. The strong bimetallic interaction was observed on the CeAg layers. Molecular adsorption of carbon monoxide on CeAg was demonstrated. We also observed intensive reaction of these layers with oxygen. By measurements in different directions of surface Brillouin zone, we managed to reconstruct the band structure of the prepared CeO2/Cu(111) layer. We have shown that the Cu substrate interacts weakly with deposited CeO2 layer. This interaction results in a charge transfer from Cu into CeO2. Overall, in the valence spectrum we have identified three main electron bands corresponding to O 2p state bound in CeO2. It has been proven that the deposition of Ni on CeO2 layers leads to partial...
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ESTIMATION OF HAPLOTYPE FREQUENCIES FROM DATA ON UNRELATED PEOPLESinha, Moumita January 2007 (has links)
No description available.
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Stellar Death in the Nearby UniverseHoloien, Thomas Warren-Son 27 October 2017 (has links)
No description available.
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Taking Measure of the Menagerie: Observational Constraints on Supernovae and Their ProgenitorsVallely, Patrick John 06 September 2022 (has links)
No description available.
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Nb3Sn Targets Synthesis via Liquid Tin Diffusion for Thin Films DepositionsZanierato, Matteo, Azzolini, Oscar, Cavazzani, Jonathan, Chyhyrynets, Eduard, Garcia Diaz, Vanessa, Glisenti, Antonella, Keppel, Giorgio, Ragazzo, Nico, Stivanello, Fabrizio, Pira, Cristian 21 September 2022 (has links)
The deposition of superconducting Nb3 Sn on copper accelerating cavities is interesting for
the higher thermal conductivity of copper compared to common Nb substrates. The better heat
exchange would allow the use of cryocoolers reducing cryogenic costs and the risk of thermal
quench [1]. The magnetron sputtering technology allows the deposition of Nb 3 Sn on substrates
different than Nb, however the coating of substrates with complex geometry (such as elliptical
cavities) may require target with non-planar shape, which are difficult to realize with classic
powder sintering techniques. In this work, the possibility of using the Liquid Tin Diffusion
(LTD) technique to produce sputtering targets is explored. The LTD technique is a wire
fabrication technology, already developed in the past at LNL for superconducting radio
frequency (SRF) applications [2], that allows the deposition of very thick and uniform coating
on Nb substrates even with complex geometries [3]. Improvements in LTD process, proof of
concept of a single use LTD target production, and characterization of the Nb 3 Sn film coated
by DC magnetron sputtering with these innovative targets are reported in this work.
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