178,693 research outputs found
Obtenção, caracterização físico química de vidros e vitro-cerâmicos baseados no sistema Li2-ZrO2-BaO-SiO2
Get PDFDissertação (Mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas. Curso de Pós-Graduação em QuímicaNeste trabalho encontra-se descrita a preparação de vidros e vitro-cerâmicos de composição 29 % Li2O - 1% ZrO2 - x% BaO - (70 - x %) SiO2, onde x = 0, 2, 3, 5, e 6 % em mol de BaO, obtidos pelo método clássico de fusão. Os materiais foram caracterizados por Difração de Raios-X, Espectroscopia Raman, Espectroscopia no Infravermelho, Espectroscopia de Fotoelétrons Excitados por Raio-X, Microscopia Eletrônica de Varredura e Análise Térmica Diferencial. Determinaram-se o mecanismo e a cinética de cristalização dos vidros, além das propriedades físico-químicas microdureza e durabilidade química
Spectroscopic properties of Yb3+-doped TeO2-BaO-BaF2-Nb2O5-based oxyfluoride tellurite glasses
No full text
A series of oxyfluoride glasses with the compositions of 75 mol% TeO2, 10 mol% Nb2O5, (15 mol%-x) BaO, x BaF2 (x = 0 mol%, 5 mol%, 10 mol%, 15 mol%) doped with Yb2O3 were prepared by the melt-quenching method. Their emission cross-sections, fluorescence lifetimes, and gain properties were investigated by using the absorption spectra and the fluorescence decay curves. The results show that by substituting BaF2 for BaO, the emission cross-section decreases from 1.37 pm(2) to 1.21 pm(2), and the fluorescence lifetime increases from 0.71 ms to 0.96 ms. These properties indicate that this oxyfluoride tellurite glass may have potential uses as the Yb2O3-doped gain medium in a solid laser.</p
[Report to Chief J. E. Curry, by an unknown author #1]
No full textReport to Chief J. E. Curry, by an unknown author. The report contains a list of officers who gave depositions to the United States Attorney
[Report to Chief J. E. Curry, by an unknown author #2]
No full textReport to Chief J. E. Curry, by an unknown author. The report contains a list of officers who gave depositions to the United States Attorney
Collisional depolarization of state selected (J,M J ) BaO A 1Σ+ measured by optical–optical double resonance
Get PDFThe optical–optical double resonance (OODR) technique is used to investigate the change in magnetic quantum number (M) a state selected molecule undergoes on collision with other molecules. A first linearly polarized dye laser prepares A 1Σ+BaO(v = 1) in the J = 1, M = 0 sublevel. The extent of collisional transfer to other M sublevels of both J = 1 and J = 2 is then probed by a second polarized dye laser which induces fluorescence from the C 1Σ+ state. Elastic collisions (ΔJ = 0) between BaO (A 1Σ+) and CO2 are observed to change M from 0 to ±1 leaving J unchanged. The total elasticM‐changing cross section is σΔM CO2 = 8.4±2.4 Å2. Inelastic collisions (ΔJ = +1’ which transfer molecules to j = 2 also cause M changes. with both Ar and CO2 as collision partners. M, the s p a c e‐f i x e d projection of J, is found to be neither conserved nor randomized. Quantum atom–diatom collision models with quantization axis along the relative velocity vector are considered. Transition amplitudes in this system are evaluated using the l‐dominant and CS approximations
Fibras de vidro a base de Li20 - Zr02 - BaO - Si02 recobertas com Nb205 para utilização em micro-extração em fase sólida
Get PDFTese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas. Programa de Pós-graduação em QuímicaNeste trabalho são descritas as metodologias para obtenção e modificações da superfície de fibras de vidro de composição Li2O-ZrO2-BaO-SiO2. Apresenta-se também as aplicações destas fibras na determinação, por SPME, de fenol e de uma mistura de álcoois. Para obtenção das fibras de vidro construiu-se um equipamento, o qual baseia-se na técnica de estiramento. As fibras de vidro foram recobertas utilizando-se duas técnicas: Decomposição de Organometálicos, onde o etóxido de nióbio (V) foi empregado como reagente precursor do óxido de nióbio (V), e Deposição de Vapor Químico, na qual fez-se uso do cloreto de nióbio como precursor do óxido de nióbio (V).Utilizou-se da técnica de Microscopia Eletrônica de Varredura para avaliar a morfologia das fibras sem recobrimento e recobertas. O recobrimento com óxido de nióbio sobre a superfície das fibras foi estudado pela técnica de "Color Map" e as análises químicas realizadas pela Microssonda de Energia Dispersiva, ambas as técnica acopladas ao MEV. A Técnica de Micro-extração em Fase Sólida foi utilizada para avaliar a capacidade de adsorsão de compostos polares e apolares pelas fibras recobertas. Com os resultados obtidos, verficou-se que pela técnica de CVD obtem-se fibras com um recobrimento mais homogêneo e espesso. Estas fibras apresentaram melhor eficiência no processo de adsorção como verificado pelos resultados cromatográficos
HOD-dependent systematics for luminous red galaxies in the DESI 2024 BAO analysis
No full textJ. Mena-Fernández et al. -- Dark Energy Spectroscopic Instrument (DESI) survey Year 1 results. -- ArXiv ePrint: 2404.03008In this paper, we present the estimation of systematics related to the halo occupation distribution (HOD) modeling in the baryon acoustic oscillations (BAO) distance measurement of the Dark Energy Spectroscopic Instrument (DESI) 2024 analysis. This paper focuses on the study of HOD systematics for luminous red galaxies (LRG). We consider three different HOD models for LRGs, including the base 5-parameter vanilla model and two extensions to it, that we refer to as baseline and extended models. The baseline model is described by the 5 vanilla HOD parameters, an incompleteness factor and a velocity bias parameter, whereas the extended one also includes a galaxy assembly bias and a satellite profile parameter. We utilize the 25 dark matter simulations available in the AbacusSummit simulation suite at z=0.8 and generate mock catalogs for our different HOD models. To test the impact of the HOD modeling in the position of the BAO peak, we run BAO fits for all these sets of simulations and compare the best-fit BAO-scaling parameters α iso and α AP between every pair of HOD models. We do this for both Fourier and configuration spaces independently, using post-reconstruction measurements. We find a 3.3σ detection of HOD systematic for α AP in configuration space with an amplitude of 0.19%. For the other cases, we did not find a 3σ detection, and we decided to compute a conservative estimation of the systematic using the ensemble of shifts between all pairs of HOD models. By doing this, we quote a systematic with an amplitude of 0.07% in α iso for both Fourier and configuration spaces; and of 0.09% in α AP for Fourier space.Peer reviewe
Alexander J. DeVoogt: Limits of the mind: Towards a characterisation of Bao mastership.: Book Review.
Get PDFManqala games are played in large parts of Africa, Asia, the Caribbean, South-America and some parts of Europe. Bao is the variation which is found on the East African coast, and only in the Swahili speaking areas. Ways of playing Bao though differ along the coast, and de Voogt focused his research on the sophisticated variant of Zanzibar. The author deals with this Zanzibar variation of Bao in analogy to chess. The first aim of his research project was to find out what distinguishes a master of Bao from an ordinary player. Psychological methods, derived from the study of chess playing are his main methodological instruments, which make the book a remarkable study in the psychology of players, and the role of memory and calculation. His second aim is to introduce Bao to the field of computer games, comparable to computer-based chess
RELATIVE TRANSITION MOMENTS AMONG EXCITED ELECTRONIC STATES AND THE GROUND STATE OF BaO
No full textAuthor Institution:The C state of BaO has been excited using optical double resonance. Relative emission intensities to various lower excited states and to the ground state were measured using a calibrated detection system. The resulting relative transition moments were then used to interpret vibronic hot band intensities from existing data in terms of relative populations of BaO metastable states in Ba + oxidant chemiluminescent reactions
Emergent Capabilities for Collaborative Teams in the Evolving Web Environment
No full textThis paper reports on our investigation of the latest advances for the Social Web, Web 2.0 and the Linked Data Web. These advances are discussed in terms of the latest capabilities that are available (or being made available) on the Web at the time of writing this paper. Such capabilities can be of significant benefit to teams, especially those comprised of multinational, geographically-dispersed team members. The specific context of coalition members in a rapidly formed diverse military context such as disaster relief or humanitarian aid is considered, where close working between non-government organisations and non-military teams will help to achieve results as quickly and efficiently as possible. The heterogeneity one finds in such teams, coupled with a lack of dedicated private network infrastructure, poses a number of challenges for collaboration, and the current paper represents an attempt to assess whether nascent Web-based capabilities can support such teams in terms of both their collaborative activities and their access to (and sharing of) information resources
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