• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 261
  • 65
  • 51
  • 32
  • 26
  • 16
  • 15
  • 13
  • 6
  • 5
  • 4
  • 4
  • 4
  • 4
  • 4
  • Tagged with
  • 628
  • 333
  • 140
  • 129
  • 62
  • 56
  • 45
  • 43
  • 43
  • 41
  • 39
  • 38
  • 37
  • 36
  • 35
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
341

Condition Of Live Fire-Scarred Ponderosa Pine Eleven Years After Removing Partial Cross-Sections

Heyerdahl, Emily K., McKay, Steven J. 06 1900 (has links)
Our objective is to report mortality rates for ponderosa pine trees in Oregon ten to eleven years after removing a fire-scarred partial cross-section from them, and five years after an initial survey of post-sampling mortality. We surveyed 138 live trees from which we removed fire-scarred partial crosssections in 1994/95 and 387 similarly sized, unsampled neighbor trees of the same species. These trees were from 78 plots distributed over about 5,000 ha at two sites in northeastern Oregon. The annual mortality rate for sectioned trees from 1994/95 to 2005 was 3.6% compared to 2.1% for the neighbor trees. However, many of the trees that died between 2000 and 2005 were likely killed by two prescribed fires at one of the sites. Excluding all trees in the plots burned by these fires (regardless of whether they died or not), the annual mortality rate for sectioned trees was 1.4% (identical to the rate from 1994/95 to 2000) compared to 1.0% for neighbor trees. During these fires, a greater proportion of sectioned trees died than did catfaced neighbor trees (80% versus 64%) but the difference was not significant.
342

L-Shell X-Ray Production Cross Sections for ₂₀Ca, ₂₆Fe, ₂₈Ni, ₂₉Cu, ₃₀Zn, ₃₁Ga, and ₃₂Ge by Hydrogen, Helium, and Lithium Ions

McNeir, Michael Ridge 05 1900 (has links)
L-shell x-ray production cross sections are presented for Fe, Ni, Cu, Zn, Ga, and Ge by 0.5- to 5.0-MeV protons and by 0.5- to 8.0-MeV helium ions and Ca, Fe, Ni, Cu, and Ge by 0.75- to 4.5-MeV lithium ions. These measurements are compared to the first Born theory and the perturbed-stationary- state theory with energy-loss, Coulomb deflection, and relativistic corrections (ECPSSR). The results are also compared to previous experimental investigations. The high precision x-ray measurements were performed with a windowless Si(Li) detector. The efficiency of the detector was determined by the use of thin target atomic-field bremsstrahlung produced by 66.5 keV electrons. The measured bremsstrahlung spectra were compared to theoretical bremsstrahlung distributions in order to obtain an efficiency versus energy curve. The targets for the measurement were manufactured by the vacuum evaporation of the target element onto thin foils of carbon. Impurities in the carbon caused interferences inthe L-shell x-ray peaks. Special cleansing procedures were developed that reduced the impurity concentrations in the carbon foil, making the use of less than 5 μg/cm^2 targets possible. The first Born theory is seen to greatly overpredict the data at low ion energies. The ECPSSR theory matches the data very well at the high energy region. At low energies, while fitting the data much more closely than the first Born theory, the ECPSSR theory does not accurately predict the trend of the data. This is probably due to the onset of molecular-orbital effects, a mechanism not accounted for in the ECPSSR theory.
343

[en] VISUALIZATION OF ARBITRARY CROSS SECTION OF UNSTRUCTURED MESHES / [pt] VISUALIZAÇÃO DE SEÇÕES DE CORTE ARBITRÁRIAS DE MALHAS NÃO ESTRUTURADAS

BERNARDO BIANCHI FRANCESCHIN 13 January 2015 (has links)
[pt] Na visualização de campos escalares de dados volumétricos, o uso de seções de corte é uma técnica eficaz para se inspecionar a variação do campo no interior do domínio. A técnica de visualização consiste em mapear sobre a superfície da seção de corte um mapa de cores, o qual representa a variação do campo escalar na interseção da superfície com o volume. Este trabalho propõe um método eficiente para o mapeamento de campos escalares de malhas não estruturadas em seções de corte arbitrárias. Trata-se de um método de renderização direta (a interseção da superfície com o modelo não é extraída) que usa a GPU para garantir bom desempenho. A idéia básica do método proposto é utilizar o rasterizador da placa gráfica para gerar os fragmentos da superfície de corte e calcular a interseção de cada fragmento com o modelo em GPU. Para isso, é necessário testar a localização de cada fragmento na malha não estruturada de maneira eficiente. Como estrutura de aceleração, foram testadas três variações de grades regulares para armazenar os elementos (células) da malha, e cada elemento é representado pela lista de planos de suas faces, facilitando o teste de pertinência fragmento-elemento. Uma vez determinado o elemento que contém o fragmento, são aplicados procedimentos para interpolar o campo escalar e para identificar se o fragmento está próximo à fronteira do elemento, a fim de representar o aramado (wireframe) da malha na superfície de corte. Resultados obtidos demonstram a eficácia e a eficiência do método proposto. / [en] For the visualization of scalar fields in volume data, the use of cross sections is an effective technique to inspect the field variation inside the domain. The technique consists in mapping, on the cross section surfaces, a colormap that represents the scalar field on the surfasse-volume intersection. In this work, we propose an efficient method for mapping scalar fields of unstructured meshes on arbitrary cross sections. It is a direct-rendering method (the intersection of the surface and the model is not extracted) that uses GPU to ensure efficiency. The basic idea is to use the graphics rasterizer to generate the fragments of the cross-section surface and to compute the intersection of each fragment with the model. For this, it is necessary to test the location of each fragment with respect to the unstructured mesh in an efficient way. As acceleration data structure, we tested three variations of regular grids to store the elements (cells) of the mesh, and each elemento is represented by the list of face planes, easing the in-out test between fragments and elements. Once the element that contains the fragment is determined, it is applied procedures to interpolate the scalar field and to check if the fragment is close to the element boundary, to reveal the mesh wireframe on the surface. Achieved results demonstrate the effectiveness and the efficiency of the proposed method.
344

Relações interpessoais na interação midiática: recursos de envolvimento na constituição de práticas discursivas de conselho em revistas de nicho / Interpersonal relations in the mediatic interaction: resources of involvement in the constitution of discursive practice of counselling in niche magazines

Rodrigues, Rafaela Baracat Ribeiro 03 November 2016 (has links)
Nesta pesquisa, temos por objeto de estudo o envolvimento interpessoal. Buscamos descrever um conjunto de opções linguísticas que constitui uma atividade interativa e que tenham por finalidade gerenciar o contato com o leitor. Nosso objetivo é analisar o papel do envolvimento e delinear sua rede de recursos na construção das relações interpessoais. Para tanto, investigamos textos produzidos no âmbito da interação midiática, em particular em revistas de nicho, uma vez que favorecem a particularidade da relação com o público alvo, empregando em suas publicações estratégias para criar afinidade e identificação com o mercado consumidor, além de investir na atratividade dos textos. Selecionamos como corpus um espaço interativo composto por cartas de leitores e respostas das revistas às perguntas enviadas no caso, por homens adultos, mulheres adultas e mulheres adolescentes , que constituem os textos das seções Pergunte à Vizinha e Pergunte ao Beto, o Barman (revista Mens Health), Pergunte ao Amigo Gay e Pergunte ao Vizinho (revista Womens Health) e Arrasa! Ficadas e rolos (revista Atrevida). Por oferecer soluções sucintas para situaçõesproblema do cotidiano, tais seções caracterizam-se como prática discursiva de aconselhamento, e, para analisá-las, respaldamo-nos na abordagem sistêmico-funcional, com foco na metafunção interpessoal, a fim de depreender os recursos responsáveis pela construção do envolvimento, complementando com estudos a respeito do que ocorre na dinâmica da interação, para verificar de que maneira são efetivados a solidariedade e o estreitamento dos vínculos entre revista de nicho e leitor. Particularmente, fundamentamo-nos na concepção e nas categorias propostas por Gonçalves Segundo (2011), e, em diálogo com essa perspectiva, a partir da análise do corpus, pudemos ampliar a rede de opções linguísticas que constroem vínculos e buscam atrair a atenção dos leitores. Os resultados da investigação apontam variadas opções paradigmáticas que desempenham a função de tracionar e atrair o leitor e que formam a rede de envolvimento, bem como revelam o papel de relevância dos recursos dessa rede na prática de conselhos em revistas de nicho, por possibilitar que efeitos de empatia sejam neles insculpidos, sinalizando padrões interpessoais que enfatizam o gerenciamento interativo. / This research aims to study the interpersonal involvement. We seek to describe a set of linguistic options that constitutes an interactive activity and whose purpose is to manage the contact with the reader. Our objective is analyzing the role of involvement and delineating its network resources in the construction of interpersonal relations. To this end, we investigate texts produced within a mediatic interaction approach, specifically in Brazilian niche magazines, in view of the fact that they foster the relation with the targeted public, embracing in their publications strategies to promote bonding and identification with the consumer market, besides investing in attractiveness of the texts. We have selected as corpus an interactive space formed by letters from readers and replies from the magazines to the questions sent by adult men and women, and teenage girls, which compound the texts of the sections Pergunte à Vizinha and Pergunte ao Beto, o Barman (Mens Health), Pergunte ao Amigo Gay and Pergunte ao Vizinho (Womens Health) and Arrasa! Ficadas e rolos (Atrevida). Since they offer simple solutions for daily-basis problems, those sections are characterized as discursive practice of counselling, and, in order to analyze them we employed the systemic functional approach, focusing on interpersonal metafunction, so as to understand the responsible resources in the construction of involvement, adding studies regarding the dynamics of interaction in order that it is possible to verify solidarity and interpersonal bonds between niche magazine and the reader. Particularly, we are based on the conception and categories proposed by Gonçalves Segundo (2011), and, in dialogue with this perspective, from the analysis of the corpus, it was possible to extend the network linguistic options that build bonds and seek to attract the attention of readers. The results of the investigation suggest a varied number of paradigmatic options which perform the function of traction and attract the reader, build an involvement network, as well as reveal the role of relevance of these network resources in the practice of counselling in niche magazines due to the allowance-insertion of empathy effects, signaling to interpersonal patterns which emphasize the interaction management.
345

Medida do alinhamento atômico de Ta, W e Au por impacto de elétrons pela distribuição angular dos raios x L / Measurement of atomic alignment of Ta, W and Au by electron impact from L x-ray angular distribution

Barros, Suelen Fernandes de 18 May 2018 (has links)
Foram realizadas medidas do alinhamento atômico do Ta, W e Au depois da ionização da subcamada L3 desses elementos por impacto de elétrons, via distribuição angular das linhas de raios x L, empregando alvos finos. As medições foram realizadas na linha de feixe de 10100 keV do Microtron de São Paulo. Os alvos foram confeccionados no Laboratório de Filmes Finos, pela técnica de deposição física de vapor (alvo de Au), e no Laboratório de Materiais Magnéticos, pela técnica de sputtering (alvos de Ta e W), enquanto que a caracterização deles foi realizada no Laboratório de Materiais e Feixes Iônicos, pela técnica de espectrometria de retroespalhamento Rutherford. O Microtron de São Paulo, bem como os laboratórios onde os alvos foram confeccionados e caracterizados, estão no Instituto de Física da Universidade de São Paulo. Os raios x decorrentes da ionização dos alvos foram detetados simultaneamente por três Silicon Drift Detectors localizados a 31°, 90° e 125° com relação à direção do feixe incidente. A determinação da eficiência de pico dos detetores foi realizada com um modelo analítico testado separadamente. As intensidades das linhas do multipleto de raios x L foram ajustadas em um único procedimento empregando funções Voigt para descrevê-las. O parâmetro de alinhamento A20 foi estimado a partir do conjunto de intensidades das linhas Ll, L1 e L2. A fim de comparar os resultados experimentais com as previsões teóricas foi calculado o parâmetro de alinhamento com a aproximação de Born de ondas planas não relativística, empregando as aproximações de HartreeSlater e DiracHartreeSlater para descrever os potenciais atômicos. Os resultados experimentais confirmaram a emissão não isotrópica dos raios x decorrentes de vacâncias preenchidas na subcamada L3, sendo que a magnitude desta anisotropia varia com a energia do feixe de elétrons incidente. Além disso, foram observadas anisotropias de sinais opostos para as linhas L1 e L2. A dependência em energia do parâmetro de alinhamento A20 mostra uma queda rápida de A20, com duas inversões de sinal, uma em torno de 2 E/E(L3) e outra em torno de 8 E/E(L3), e um valor não nulo de alinhamento em torno de 10 E/E(L3), para os três elementos estudados. A comparação dos resultados experimentais com os cálculos realizados mostra um bom acordo ate cerca de 5 E/E(L3) para o feixe de elétrons incidente, a partir deste ponto o experimento evidencia uma segunda inversão no sinal de A20, que não é prevista por essa teoria. Este é, a nosso saber, o primeiro trabalho a quantificar o alinhamento atômico na ionização de átomos pesados por impacto de elétrons, via distribuição angular de raios x na faixa de 1 a 10 E/E(L3). / Measurements of the atomic alignment of Ta, W and Au after the ionization of the L3 subshell of these elements were performed by electron impact via the angular distribution of x-ray lines employing thin targets. The targets were made in the Laboratório de Filmes Finos, by the technique of physical vapor deposition (Au target), and in the Laboratório de Materiais Magnéticos, by the sputtering technique (Ta and W targets), while their characterization was performed in the Laboratório de Materiais e Feixes Iônicos, by Rutherford Backscattering Spectrometry. The Microtron of São Paulo, as well as the laboratories where the targets were made and characterized, are placed at Instituto de Física of the Universidade de São Paulo. The x-rays from the ionization of the targets were detected simultaneously by three Silicon Drift Detectors placed at 31°, 90° and 125° with respect to the direction of the incident beam. The determination of the full energy peak efficiency of the detectors was performed with an analytical model previously tested. In the data analysis the L x-ray multiplet lines were fitted in a single procedure employing Voigt functions to describe them, and the Ll, L1 and L2 lines were employed simultaneously in the estimation of the alignment parameter A20. In order to compare the experimental results with the theoretical predictions, the alignment parameter was calculated with the non-relativistic plane-wave Born approximation using HartreeSlater and DiracHartreeSlater atomic potentials. The experimental results confirmed the nonisotropic emission of x-rays from filled vacancies in the L3 subshell, with the magnitude of this anisotropy varying with the energy of the incident electron beam. In addition, anisotropies of opposite signs were observed for the L1 and L2 lines. The energy dependence of the alignment parameter A20 shows a sharp fall of A20, with two sign inversions, one around 2 E/E(L3) and another around 8 E/E(L3), and a non-zero alignment value around 10 E/E(L3), for the three studied elements. Comparison of the experimental results with the performed calculations shows a good agreement up to about 5 E/E(L3) for the incident electron beam, from which the experiment evidences a second inversion in the sign of A20, which is not predicted by this theory. This is, to our knowledge, the first work to quantify the atomic alignment in the ionization of heavy atoms by electron impact, via an angular distribution of x-rays in the interval from 1 to 10 E/E(L3).
346

Microbiota fóssil em sílex da Formação Assistência (Subgrupo Irati, Permiano, Bacia do Paraná) no Estado de São Paulo / Fossil microbiota in chert from Assistência Formation (Irati Subgroup, Permian, Paraná Basin) in São Paulo State

Calça, Cleber Pereira 22 February 2008 (has links)
O estudo de lâminas delgadas de sílex de origem diageneticamente precoce de diversos níveis estratigráficos e localidades da Formação Assistência no Estado de São Paulo revelou pela primeira vez uma assembléia de microorganismos orgânicos delicados, excepcionalmente bem preservados neste importante marco estratigráfico e paleontológico do Neopermiano da Bacia do Paraná. Esta assembléia consiste principalmente de organismos unicelulares, dominados por cianobactérias, tanto solitárias como coloniais, sem nenhum indício de filamentos. Inclui também uma provável clorófita cocoidal, grãos de pólen e fitoclastos, além de alguns microfósseis de afinidades incertas. Estudos paleopalinológicos de resíduos orgânicos desta formação nunca detectaram os elementos delicados desta microbiota. O exame petrográfico permitiu observar não somente todos os microorganismos fósseis em três dimensões no interior da rocha, mas também a distribuição espacial original dos microorganismos e suas relações com os outros componentes da rocha. Isto facilitou a avaliação da variedade morfológica dos microfósseis resultante da degradação e permitiu inferir padrões ontogênicos de alguns dos táxons descritos. Dentre eles, foram reconhecidos 14 morfotipos, reunidos em cinco espécies (todas novas) com afinidades biológicas conhecidas (quatro espécies de cianobactérias e uma clorófita) e cinco táxons incertae sedis (dois novos). A microbiota ocorre principalmente no sílex na base da formação. Constitui massas volumosas e densas preservadas in situ interpretadas como organismos originalmente bentônicos, capazes de formar esteiras microbianas e pequenos estromatólitos. A sedimentologia aliada à ampla extensão geográfica, ao hábito, à abundância e à natureza exclusivamente unicelular dos microorganismos fósseis, alem de exemplos atuais análogos, indicam um paleoambiente aquoso raso de salinidade alta, talvez hipersalina com salinidade variável. / The study of petrographic thin sections of early diageneteic chert from diverse levels and localities of the Assistência Formation in the state of São Paulo, Brazil, revealed for the first time an exceptionally well-preserved assemblage of delicate fossil microorganisms in this important stratigraphic and paleontological Early Permian marker unit of the Paraná Basin. This assemblage consists primarily of delicate colonial and solitary unicellular microfossils, dominated by cyanobacteria, without any evidence whatsoever of filamentous microorganisms. It also includes a probable cocoidal chlorophyte, pollen grains and phytoclasts, as well as several less common microfossils of uncertain biological affinity. None of the delicate microfossils of this assemblage have ever been detected in palynological analyses of organic residues from this formation. The study of thin sections made it possible to observe not only all of the fossil microorganisms in three dimensions within the rock but also their original spatial distribution and relationships with other components of the rock. This facilitated evaluation of the morphological diversity of the fossil microorganisms and permitted inferences as to possible ontogenetic patterns. Fourteen morphotypes were recognized among the more delicate microfossils and attributed to five species (all new) of known biological affinities (four species of cyanobacterias and one chlorophyte) and five taxa of Incertae Sedis. The fossil microbiota occurs principally at the base of the formation as dense, voluminous masses interpreted as remains of an in situ benthonic microbiota of photosynthetic microorganisms capable of forming microbial mats and small stromatolites. The sedimentology, together with the widespread distribution, habit, abundance and exclusively unicellular nature of the fossil microorganisms and the paleoenvironmental implications suggested by analogous modern examples, are consistent with a shallow aquatic habitat of high and perhaps variable salinity for the microbiota.
347

Reciprocity between Emission and Absorption for Rare Earth Ions in Glass

Martin, Rodica M. 28 April 2006 (has links)
The power of the McCumber theory [D. E. McCumber, Phys. Rev. 136, A954-957 (1964)] consists in its ability to accurately predict emission cross section spectra from measured absorption, and vice versa, including both absolute values and spectral shapes. While several other theories only allow the determination of integrated cross sections, the McCumber theory is unique in generating the spectral shape of a cross section without any direct measurements regarding that cross section. The present work is a detailed study of the range of validity of the McCumber theory, focussing particularly on those aspects that most critically affect its applicability to transitions of rare earth ions in glasses. To analyze the effect of the spectral broadening on the accuracy of the technique, experiments were performed at room and low temperature. The theory was tested by comparing the cross sections calculated using the McCumber relation with those obtained from measurements. At room temperature, a number of ground state transitions of three different rare earth ions (Nd, Er and Tm) in oxide and fluoride glass hosts have been studied. Special attention was paid to the consistency of the measurements, using the same experimental setup, same settings and same detection system for both absorption and fluorescence measurements. Other aspects of the experimental procedure that could generate systematic errors, like fluorescence reabsorption and baseline subtraction uncertainties in the absorption measurements, were carefully investigated. When all these aspects are properly accounted for, we find in all cases an excellent agreement between the calculated and the measured cross section spectra. This suggests that the McCumber theory is not limited to crystalinne hosts, but describes quite well the reciprocity between emission and absorption for the broader transitions of rare earths in glassy hosts. This good agreement does not hold, however, for the low temperature results. The distortion observed in this case follows the theoretically predicted behavior, and corresponds to the amplification of the gaussian wings that describes the inhomogeneous type of broadening. Our results suggest that the McCumber theory must be used with caution for temperatures below 200 K.
348

Microbiota fóssil em sílex da Formação Assistência (Subgrupo Irati, Permiano, Bacia do Paraná) no Estado de São Paulo / Fossil microbiota in chert from Assistência Formation (Irati Subgroup, Permian, Paraná Basin) in São Paulo State

Cleber Pereira Calça 22 February 2008 (has links)
O estudo de lâminas delgadas de sílex de origem diageneticamente precoce de diversos níveis estratigráficos e localidades da Formação Assistência no Estado de São Paulo revelou pela primeira vez uma assembléia de microorganismos orgânicos delicados, excepcionalmente bem preservados neste importante marco estratigráfico e paleontológico do Neopermiano da Bacia do Paraná. Esta assembléia consiste principalmente de organismos unicelulares, dominados por cianobactérias, tanto solitárias como coloniais, sem nenhum indício de filamentos. Inclui também uma provável clorófita cocoidal, grãos de pólen e fitoclastos, além de alguns microfósseis de afinidades incertas. Estudos paleopalinológicos de resíduos orgânicos desta formação nunca detectaram os elementos delicados desta microbiota. O exame petrográfico permitiu observar não somente todos os microorganismos fósseis em três dimensões no interior da rocha, mas também a distribuição espacial original dos microorganismos e suas relações com os outros componentes da rocha. Isto facilitou a avaliação da variedade morfológica dos microfósseis resultante da degradação e permitiu inferir padrões ontogênicos de alguns dos táxons descritos. Dentre eles, foram reconhecidos 14 morfotipos, reunidos em cinco espécies (todas novas) com afinidades biológicas conhecidas (quatro espécies de cianobactérias e uma clorófita) e cinco táxons incertae sedis (dois novos). A microbiota ocorre principalmente no sílex na base da formação. Constitui massas volumosas e densas preservadas in situ interpretadas como organismos originalmente bentônicos, capazes de formar esteiras microbianas e pequenos estromatólitos. A sedimentologia aliada à ampla extensão geográfica, ao hábito, à abundância e à natureza exclusivamente unicelular dos microorganismos fósseis, alem de exemplos atuais análogos, indicam um paleoambiente aquoso raso de salinidade alta, talvez hipersalina com salinidade variável. / The study of petrographic thin sections of early diageneteic chert from diverse levels and localities of the Assistência Formation in the state of São Paulo, Brazil, revealed for the first time an exceptionally well-preserved assemblage of delicate fossil microorganisms in this important stratigraphic and paleontological Early Permian marker unit of the Paraná Basin. This assemblage consists primarily of delicate colonial and solitary unicellular microfossils, dominated by cyanobacteria, without any evidence whatsoever of filamentous microorganisms. It also includes a probable cocoidal chlorophyte, pollen grains and phytoclasts, as well as several less common microfossils of uncertain biological affinity. None of the delicate microfossils of this assemblage have ever been detected in palynological analyses of organic residues from this formation. The study of thin sections made it possible to observe not only all of the fossil microorganisms in three dimensions within the rock but also their original spatial distribution and relationships with other components of the rock. This facilitated evaluation of the morphological diversity of the fossil microorganisms and permitted inferences as to possible ontogenetic patterns. Fourteen morphotypes were recognized among the more delicate microfossils and attributed to five species (all new) of known biological affinities (four species of cyanobacterias and one chlorophyte) and five taxa of Incertae Sedis. The fossil microbiota occurs principally at the base of the formation as dense, voluminous masses interpreted as remains of an in situ benthonic microbiota of photosynthetic microorganisms capable of forming microbial mats and small stromatolites. The sedimentology, together with the widespread distribution, habit, abundance and exclusively unicellular nature of the fossil microorganisms and the paleoenvironmental implications suggested by analogous modern examples, are consistent with a shallow aquatic habitat of high and perhaps variable salinity for the microbiota.
349

Transmission and capture cross section measurements by the time-of-flight technique for validation of pile-oscillation experiments in the Minerve reactor / Mesures des sections efficaces de réaction par la technique du temps de vol pour la validation des mesures d'oscillation réalisées dans le réacteur Minerve

Salamon, Lino 28 September 2018 (has links)
Ce travail présente l'étude de faisabilité des mesures de transmission avec des échantillons MINERVE à l'installation de temps de vol GELINA. L'idée principale était de définir des procédures pour analyser les résultats des mesures de transmission réalisées avec des échantillons cylindriques ne répondant pas à la géométrie de transmission idéale. La capacité d'extraire des résultats fiables a été démontrée sur l'exemple des échantillons MINERVE enrichis en argent. De plus, des mesures de transmission et de capture avec des disques standards d'argent naturel ont été effectuées pour améliorer les paramètres de résonance pour 107Ag et 109Ag. Les principales étapes de ce travail sont la réduction des données brutes (taux de comptage) pour produire des spectres de transmission et de rendement de capture, puis l'analyse des spectres avec le code d'analyse de forme des résonances REFIT. / This work presents the feasibility study of transmission measurements with the MINERVE samples at time-of-flight facility GELINA. The main idea was to define procedures to analyse results of transmission measurements using cylindrical samples which do not fulfil the ideal transmission geometry. Capability of extracting reliable results was demonstrated on the example of MINERVE samples enriched in silver. In addition, transmission and capture measurements with standard discs of natural silver were performed to improve the resonance parameters for 107Ag and 109Ag. The main steps in this work are the data reduction of measured count rate spectra to produce final transmission and capture yield spectra and the spectra analysis with the resonance shape analysis code REFIT.
350

Sex roles in the comic strips : a historical perspective--1896-1979

Snider, Marie January 2011 (has links)
Typescript (photocopy). / Digitized by Kansas Correctional Industries / Department: Journalism and Mass Communication.

Page generated in 0.071 seconds