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  • 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.
31

Transporte quântico em poços parabólicos largos / Transportation wide parabolic quantum wells

Sergio, Cássio Sanguini 25 July 2003 (has links)
A passagem progressiva de estados de Landau bidimensional (2D) para estados tridimensional (3D) foi estudada em Poços Quânticos Parabólicos (PQW) largos (W = 1000 6000 Å). Utilizou-se como técnica de transporte medidas da magnetoresistência em campo magnético intenso (B = 0 15 T) e inclinado ( = 0 90°; perpendicular paralelo), a baixas temperaturas (T = 50 mK). Observou-se, através da dependência angular das oscilações de Shubnikov de Haas ( = 0 90°), em PQWs cheios, várias sub-bandas ocupadas (5 a 8), a coexistência de estados de Landau 2D e 3D, sendo o gás 3D formado pelo colapso das sub-bandas elevadas, e o gás 2D pertencendo à primeira sub-banda. Através de cálculos do alargamento dos níveis de Landau devido ao espalhamento elástico ( = /2 , onde é o tempo quântico) e de cálculos auto-consistentes da energia de separação entre sub-bandas do PQW (ij = Ej Ei; e 12=12/2), obtiveram-se as condições 2 j-1,j para as sub-bandas elevadas j = 3,4,..., corroborando com as observações experimentais da coexistência de estados de Landau 2D e 3D no poço. Em PQWs parcialmente cheios, com apenas 2 sub-bandas ocupadas, observou-se, através do efeito do anticruzamento de níveis de Landau, de medidas da dependência angular da energia de ativação no regime de efeito Hall quântico, e de comparações com resultados de cálculos da estrutura eletrônica de PQWs em campo magnético inclinado, a coexistência de estados de Landau 2D e 3D, ocorrendo somente em campos intensos e com inclinação acentuada ( = 80 90°). Esta coexistência é diferente da mencionada anteriormente, quando od estados de Landau 3D são observados já em campo perpendicular. / The gradual progress, or evolution, of the two-dimensional (2D) toward three-dimensional (3D) Landau states was studied in wide parabolic quantum Wells (W = 1000 6000 Å). As transport technique, we used measurements of the magnetoresistence in intense (B = 0 15 T) and tilted ( = 0 90°; perpendicular parallel) magnetic Field at low temperature (T = 50 Mk). We observed in PQWs with Five to eight sub-bands occupied full well the coexistence of the 2D and 3D Landau states, through the angular dependence of the Shubnikov de Hass oscillation ( = 0 90°), where the 2D states belong to the lowest sub-band and the 3D states are formed by overlap of the other sub-bands. We calculated the level broadening due to the elastic scattering rate ( = /2 , where is the quantum time), and the energy separation between sub-bands (ij = Ej Ei; e 12=12/2). We obtained 2 j-1,j to j=3,4,... . This confirms the experimental observations of the coexistence of the 2D and 3D states in the well. We also measured PQWs partially full 2 sub-bands occupied. Experiments revel anticrossing of the Landau level (LL) belonging to the lowest sub-band and the last LL belonging to the second sub-band. Such antisrossuing occurs due to a decrease of the energy of the LL with tilt angle. This observation was supported by measurements of the angular dependence of the activation energy in the quantum Hall regime. In these measurements, we also observed the coexistence of the 2D and 3D Landau states. However, the coexistence only occurs at large tilt angles ( = 80 90°). Thus, it is different from the coexistence above mentioned, when 3D Landau states are observed already in the perpendicular magnetic field.
32

Transporte quântico em poços parabólicos largos / Transportation wide parabolic quantum wells

Cássio Sanguini Sergio 25 July 2003 (has links)
A passagem progressiva de estados de Landau bidimensional (2D) para estados tridimensional (3D) foi estudada em Poços Quânticos Parabólicos (PQW) largos (W = 1000 6000 Å). Utilizou-se como técnica de transporte medidas da magnetoresistência em campo magnético intenso (B = 0 15 T) e inclinado ( = 0 90°; perpendicular paralelo), a baixas temperaturas (T = 50 mK). Observou-se, através da dependência angular das oscilações de Shubnikov de Haas ( = 0 90°), em PQWs cheios, várias sub-bandas ocupadas (5 a 8), a coexistência de estados de Landau 2D e 3D, sendo o gás 3D formado pelo colapso das sub-bandas elevadas, e o gás 2D pertencendo à primeira sub-banda. Através de cálculos do alargamento dos níveis de Landau devido ao espalhamento elástico ( = /2 , onde é o tempo quântico) e de cálculos auto-consistentes da energia de separação entre sub-bandas do PQW (ij = Ej Ei; e 12=12/2), obtiveram-se as condições 2 j-1,j para as sub-bandas elevadas j = 3,4,..., corroborando com as observações experimentais da coexistência de estados de Landau 2D e 3D no poço. Em PQWs parcialmente cheios, com apenas 2 sub-bandas ocupadas, observou-se, através do efeito do anticruzamento de níveis de Landau, de medidas da dependência angular da energia de ativação no regime de efeito Hall quântico, e de comparações com resultados de cálculos da estrutura eletrônica de PQWs em campo magnético inclinado, a coexistência de estados de Landau 2D e 3D, ocorrendo somente em campos intensos e com inclinação acentuada ( = 80 90°). Esta coexistência é diferente da mencionada anteriormente, quando od estados de Landau 3D são observados já em campo perpendicular. / The gradual progress, or evolution, of the two-dimensional (2D) toward three-dimensional (3D) Landau states was studied in wide parabolic quantum Wells (W = 1000 6000 Å). As transport technique, we used measurements of the magnetoresistence in intense (B = 0 15 T) and tilted ( = 0 90°; perpendicular parallel) magnetic Field at low temperature (T = 50 Mk). We observed in PQWs with Five to eight sub-bands occupied full well the coexistence of the 2D and 3D Landau states, through the angular dependence of the Shubnikov de Hass oscillation ( = 0 90°), where the 2D states belong to the lowest sub-band and the 3D states are formed by overlap of the other sub-bands. We calculated the level broadening due to the elastic scattering rate ( = /2 , where is the quantum time), and the energy separation between sub-bands (ij = Ej Ei; e 12=12/2). We obtained 2 j-1,j to j=3,4,... . This confirms the experimental observations of the coexistence of the 2D and 3D states in the well. We also measured PQWs partially full 2 sub-bands occupied. Experiments revel anticrossing of the Landau level (LL) belonging to the lowest sub-band and the last LL belonging to the second sub-band. Such antisrossuing occurs due to a decrease of the energy of the LL with tilt angle. This observation was supported by measurements of the angular dependence of the activation energy in the quantum Hall regime. In these measurements, we also observed the coexistence of the 2D and 3D Landau states. However, the coexistence only occurs at large tilt angles ( = 80 90°). Thus, it is different from the coexistence above mentioned, when 3D Landau states are observed already in the perpendicular magnetic field.
33

Návrh řešení úpravy sil. I/43 v úseku Podlesí - Kuřim / Road design of /43 in section Podlesí - Kuřim

Fryčar, David January 2018 (has links)
This diploma thesis deals with the processing of complex transport solutions in the interest area of the city of Kuřim on the existing road I/43 in the Section Česká – Podlesí – Kuřim. Thus, the proposal for an adjustment of this road takes into account all modes of transport. Transit trafic or target car transport, public transport and also transport in terms of local ties. The design is processed in 4 variants, the difference being mainly in the size of the modifications to the existing road I/43. Subsequently one variant was selected for more detailed completion. This is a design solution in the 2 + 1 arrangement with interchanges of Podlesí and Kuřim – east. The proposed solution does not prevent the planned implementation of the D43 motorway.
34

Design and Simulation of a Planar Crossed-Dipole Global Navigation Satellite System (GNSS) Antenna in the L1 Frequency Band

Katragadda, Mahesh January 2012 (has links)
No description available.
35

L'imidazo[1,2-a]pyridine : fonctionnalisation et synthèse des nouveaux polyhétérocycles / Imidazo[1,2-a]pyridine : functionalization and synthesis of new polyheterocycles

Tber, Zahira 05 February 2016 (has links)
Les préparations de composés comportant un noyau imidazo[1,2-a]pyridinique constituent un thème de recherche important en synthèse organique, compte tenu des nombreuses activités biologiques qu’ils peuvent présenter. Dans la première partie, nous nous sommes concentrés sur le développement de nouvelles stratégies rapides et efficaces basées sur l’utilisation de cuivre et de fer pour fonctionnaliser la position 6 du cycle imidazo[1,2-a]pyridine avec diverses amines et divers thiols. Ensuite, nous avons appliqué avec succès cette procédure pour la préparation de thioéthers symétriques et dissymétriques en utilisant le 2-mercaptobenzooxasole, réactif économique qui ne présente aucun risque chimique. Dans le dernier volet de ce travail, nous nous sommes intéressés au développement de nouvelles réactions multicomposants en vue de synthétiser divers pyrrolo[3',2':4,5]imidazo[1,2-a]pyridines et 5-aminopyrido[2’,1’:2,3]imidazo[4,5-c]isoquinoléines. / The preparations of imidazo[1,2-a]pyridine is one of important research topic in organic synthesis, This entitie present some interesting biological activities. First, we devoleped a new rapid and efficient strategies to functionalize position 6 of the imidazo[1,2-a]pyridine with various amines and thiols catalysed by copper and iron. Then we applied this procedure to the preparation of symmetric and asymmetric thioethers using 2 mercaptobenzooxasole, which is an economical reagent and which presents no chemical risk. The last part of this work concerns the development of new multicomponent reactions for the synthesis of various pyrrolo[3',2':4,5]imidazo[1,2-a]pyridine and 5-amino pyrido[2’,1’:2,3] imidazo [4,5-c]isoquinoléines.
36

Undersökning av grundläggningsmetod, kantbalkar utförda med glas, polystyren och korslimmat-trä.

Eliasson, Daniel, Carlsson, Olle January 2023 (has links)
Byggbranschen bidrar till stora utsläpp av växthusgaser, och det är därför viktigt att utforska hållbara material för att minska påverkan. Studien fokuserar på grundfundament för mindre trähus i Sverige, där betong i platta på mark ersätts med korslimmat trä (KLT) för att reducera klimatpåverkan. Eftersom betong har hög tryckhållfasthet gjordes analys av kantbalkens kapacitet. Fyra alternativ på kantbalkar undersöks: KLT/EPS400, KLT/Foamglas, KLT/EPS s100 och EPS400. Studien bedömer även den nuvarande dimensioneringen i hållfasthetsberäkningarna. Testdata för tryckhållfasthet används för att jämföra med förväntade resultat och avgöra om beräkningsmodellen ”2:1 metoden” är tillräcklig.Syftet är att bedöma möjligheterna för användning i två hustyper hos en ledande hustillverkare i Sverige. Miljöpåverkan av alternativen beräknas med IVL Svenska Miljöinstitutets verktyg, BM, där även en betonggrund jämförs. Det utförs även en enklare insikt i skillnader av produktion mellan en klassisk betonggrund och Klaragrunden. Studien visade att 1-plansvillan Lycke kan utföras med KLT och EPS s100, och att 1,5-plansvillan Tyresund kan se möjligheter med KLT och FoamglasT4+. Studien visade också att den bästa genomsnittliga grunden är KLT och EPS s400. Genom att byta ut betongen i en platta på mark med KLT, gör det möjligt att sänka grundens CO2 utsläpp med 65-68%. / The construction industry contributes significantly to greenhouse gas emissions, making it crucial to explore sustainable materials to reduce its impact. This study focuses on foundation systems for small wooden houses in Sweden, where concrete slabs are replaced with cross-laminated timber (CLT) to decrease climate impact. Due to concrete's high compressive strength, an analysis of the edge beam's capacity was done. Four edge beam alternatives are examined: CLT/EPS400, CLT/Foamglas, CLT/EPS s100, and EPS400. The study also evaluates the current dimensioning in strength calculations. Compression strength test data is used to compare with expected results and determine if the calculation model "2:1 method" is sufficient. The aim is to assess the possibilities for use in two house types from a leading house manufacturer in Sweden. The environmental impact of the alternatives is calculated using IVL Swedish Environmental Institute's tool, BM, where a concrete foundation is also compared. There is also a brief insight into the differences in production between a traditional concrete foundation and Klaragrunden. The findings indicated that the single-story villa Lycke can be constructed using CLT and EPS s100, while the 1.5-story villa Tyresund can explore possibilities with CLT and Foamglas T4+. Moreover, the study revealed that the CLT and EPS s400 combination yielded the best average foundation. By replacing the concrete in a ground slab with CLT, it is possible to reduce the CO2 emissions from the foundation by 65-68%.
37

Blind injustice : Jesus' prophetic warning against unjust judging (Matt 7:1-5)

Chandler, Christopher N. January 2010 (has links)
This dissertation seeks to provide a plausible alternative to the consensus interpretation of Jesus' "do not judge" teaching in Matt 7:1-5. While the overwhelming majority of recent interpreters understand "do not judge" (7:1) and its concurrent sayings such as "take the log out of your own eye" (7:5) to promote a non-judgmental attitude, this monograph seeks to situate this block of teaching within a Jewish second-Temple judicial setting. To this end, an overview of the judicial system during the second Temple era is provided, after which it is argued that Matt 7:1-5 is the Matthean Jesus' halakhic, midrashic comment upon the laws for just legal judging in Lev 19:15-18, 35-36 by which he prophetically criticizes unjust legal judging. Jesus' brother James takes up this teaching in Jas 2:1-13, using it to exhort Jewish Christian leaders who judge cases within Diaspora synagogues/churches. Such an alternative interpretation of Jesus' "do not judge" teaching in Matt 7:1-5 matches well other passages in Matthew which likewise speak of judicial, brotherly conflict such as 5:21-26 and 18:15-35. Some early Christian writers who quote or allude to Matt 7:1-5 reflect a judicial understanding of these verses as well, often relating Matt 7:1-5 to Lev 19:15-18, 35-36 and/or drawing parallels between Matt 7:1-5 and one or more of the NT judicial texts which, this thesis argues, is related to it (Matt 5:21-26, 18:15-35; Jas 2:1-13).
38

Conception, synthèse et caractérisation de molécules polyhétérocycliques azotées pour la complexation spécifique de cations métalliques

Dupont, Carine 10 December 2010 (has links) (PDF)
La loi du 6 juin 2006 sur la gestion des déchets radioactifs de haute activité et à vie longue prévoit la recherche de solutions permettant la séparation et la transmutation des radioéléments à vie longue, pour réduire les quantités et la nocivité des déchets radioactifs ultimes. Ces déchets issus du retraitement du combustible nucléaire usé sont actuellement vitrifiés à La Hague. Ainsi, le projet " séparation poussée " vise à compléter le procédé industriel PUREX par le développement de procédés permettant d'extraire les actinides mineurs des raffinats PUREX où se trouvent également des produits de fission constitués principalement de lanthanides, neutrophages. Pour réaliser la séparation poussée, les actinides mineurs des raffinats PUREX doivent être séparés par des molécules spécifiques. Les BTP ou bis-triazinyl-pyridines ont été largement étudiées au CEA pour la séparation actinides(III)/lanthanides(III). Elles complexent sélectivement les actinides, mais l'origine de cette sélectivité n'est pas complètement expliquée : notamment l'influence des groupements (attachés à leur structure) sur la complexation ou la sélectivité reste à démontrer. En outre, elles sont sensibles à l'hydrolyse et à la radiolyse. La première partie du travail présente la synthèse de BTP ou de BTBP, différemment substituées pour améliorer leur résistance face à l'hydrolyse ou à la radiolyse, et une nouvelle famille de ligands polyaromatiques azotés : les BPBT, présentant un enchaînement original de cycles pyridine et triazine, différent de toutes les structures décrites jusqu'à présent dans la littérature. La seconde partie de ce travail est consacrée à l'étude physico-chimique de nouvelles molécules obtenues, en déterminant leurs constantes de protonation et de complexation, pour connaître l'influence des différents groupements sur la complexation et la sélectivité. Enfin, le troisième volet concerne l'étude des propriétés de ces ligands en extraction liquide-liquide, utilisés soit comme extractants lipophiles, soit comme complexants hydrophiles.
39

Encounter space to connect with  The “Self”  1-2-1 performances : through Circus and Movement practices

Palomar, Gemma January 2018 (has links)
This research was based on the idea of creating a space of encounter and of an encounter in space. The initial idea was to create a participatory/immersive installation framed within relational aesthetics and contemporary circus: focusing on a vital language that celebrates movement /dance, play, imagination and the magic of life. But through the process I left the concept of installation and I aim for an encounter space: blurring the boundaries with fields such as Movement, Dance Theatre, Improvisation, Circus, etc… A research to explore and develop the relationship with others, specially the audience. And how the audience can become a participant through 1-2-1 performances. Furthermore, I wanted to focus on the process of the research (inspirations, methodology, detect obstacles, making space…) rather than the outcome. The main thread is: Connecting with the “Self” state. ____reVisionesA research in how to facilitate a state of connection, essence, spontaneity and honesty to oneself, though around the idea of an immersive experience for the visitor/participant. “reVisiones” aims to create a space of encounter where participants can focus on awareness of the connection between their Body/Mind/Spirit: a "Transitional Space" where they can observe, be moved or move within as they please.
40

Naphthalene based plant regulating compounds : photophysics, direct an polyoxometalate catalysed degradation in homogeneous and heterogeneous media by layered double hydroxides / Etudes de dérivés de naphtalène utilisés comme pesticides régulateurs de la croissance de plantes : caractérisations photophysiques et études de la photodégradation directe et catalysée par les polyoxométalates en phase homogène et en phase hétérogène fixés sur des hydroxydes doubles lamellaires

Silva, Eliana Sousa da 29 July 2014 (has links)
Résumé non disponible. / Résumé non disponible.

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