41 |
Études Structurales et Photophysiques de Polymères de Coordination de Thiolates de Métaux Monétaires / Structural and photophysical studies of coordination polymers of coinage metals thiolatesVeselska, Oleksandra 17 October 2019 (has links)
Les polymères de coordination (PCs) à base de thiolates de métaux monétaires sont bien connus pour leurs propriétés luminescentes. Cependant, leurs structures sont sous-explorées. Dans cette thèse, nous présentons une étude pionnière visant la compréhension de la formation de la structure et de la corrélation ‘structure-propriétés’ des PCs homoleptiques neutres, [M(SR)]n, M = Cu(I), Ag(I), Au(I). Les composés avec les dérivés du thiophénolate étudiés dans ce travail, illustrent comment l'utilisation de certains ligands organiques fonctionnalisés conduit à la formation de réseaux 2D étendus ou de colonnes 1D par l'addition d'un encombrement stérique. De plus, la première étude structurelle comparative des PCs thiolées amorphes a été réalisée par analyse PDF. Les études photophysiques ont montré la diversité des propriétés luminescentes des PCs à base de thiolates de métaux monétaires. Des pics d'émission doubles ou multiples, un rendement quantique élevé, des émetteurs orange à proche infrarouge, des variations significatives de durée de vie en fonction de la température... toutes ces propriétés intrinsèques révèlent le potentiel élevé de ces composés pour diverses applications optiques / The coordination polymers (CPs) based on thiolates of coinage metals are well known for their luminescence properties. However, their structures stayed underexplored. In the thesis we present a pioneering study targeting the understanding of the structure formation and the ‘structure-properties’ correlation for neutral homoleptic CPs, [M(SR)]n, M = Cu(I), Ag(I), Au(I). The compounds with thiophenolate derivatives studied in the work, illustrate how the use of some functionalized organic ligands leads to the formation of extended 2D networks or 1D columns by addition of some steric hindrance. The first comparative structural study of amorphous thiolated CPs was performed by PDF analysis. The photophysical studies showed the diversity of luminescent properties of the CPs based on thiolates of coinage metals. Double or multiple emission peaks, high quantum yield of orange-toinfrared emitters, significant lifetime variation with temperature… all of these intrinsic properties reveal the high potential of these compounds for diverse optical applications
|
42 |
El uso de los Sistemas de Facturación Electrónica y el impacto tributario de su implementación en las empresas ganaderas de Lurín en el ejercicio 2018Montalvo Barbieri, César Francesco, Quequesana Solsol, Claudia Daniela 05 April 2019 (has links)
El presente trabajo de investigación tiene como finalidad evaluar el impacto tributario que tiene el uso de los sistemas de emisión electrónica a partir de la aplicación y evaluación de cada sistema para ver sus efectos tributarios, así como los efectos por la ausencia del uso del sistema y todo ello en las empresas ganaderas de Lurín para efectos del 2018 proyectando el impacto a final del año. De acuerdo con la última Resolución de Superintendencia N°254-2018/SUNAT, las empresas que han sido mencionadas en la Resolución de Superintendencia N°300-2014/SUNAT, serán obligadas a emitir facturas electrónicas a partir del año 2019. Por lo que proporciona dudas sobre qué sistema escoger o entender la diferencia entre cada una ya que SUNAT emite diversas resoluciones que llega confundir a los emisores electrónicos y otros usuarios podrían hasta no darle importancia al tema. Es por ello que las empresas deben considerar los cambios que surgirán en este nuevo proceso de facturación electrónica, y que se desarrollarán a partir de nuestra investigación cualitativa y cuantitativa.
Como parte de la metodología de investigación, hemos logrado recabar opiniones importantes de expertos y colaboradores que laboran o tienen experiencia en el sector de ganadería, a través de entrevistas a profundidad y encuestas. Del mismo modo, se desarrolló un caso práctico con el fin de evaluar los impactos tributarios y operativos en la empresa por cada SEE.
Después de haber analizado los datos recolectados y haber identificado cómo es el impacto en las empresas, se exponen las conclusiones y recomendaciones que beneficiarán a las empresas del sector ganadero con el propósito de que elijan o empleen el mejor SEE para su negocio.
Palabras Claves: Impacto Tributario; Sistema de Emisión Electrónica; Facturas Electrónicas; Emisores Electrónicos. / The purpose of this research work is to evaluate the tax impact of the use of electronic emission systems from the application and evaluation of each system to see their tax effects, as well as the effects of the absence of the use of the system and all this in the Lurin livestock companies for the purposes of 2018 projecting the impact at the end of the year. In accordance with the latest Superintendency Resolution No. 254-2018/SUNAT, the companies that have been mentioned in Superintendency Resolution No. 300-2014/SUNAT will be obliged to issue electronic invoices as of 2019. Provides doubts about which system to choose or understand the difference between each one since SUNAT issues various resolutions that confuses the electronic issuers and other users could not even give importance to the issue. That is why companies must consider the changes that will arise in this new electronic invoicing process, and that will be developed from our qualitative and quantitative research.
As part of the research methodology, we have managed to gather important opinions from experts and collaborators who work or have experience in the livestock sector, through in-depth interviews and surveys. In the same way, a case study was developed in order to evaluate the tax and operational impacts on the company by each ESS.
After analyzing the data collected and having identified what is the impact on the companies, the conclusions and recommendations that will benefit the companies of the livestock sector with the purpose of choosing or using the best ESS for their business are exposed. / Tesis
|
43 |
Methodische Untersuchungen zum Einsatz von Positronenemittern für die Dichtebestimmung in leichten MedienHensel, Frank 31 March 2010 (has links) (PDF)
In der vorliegenden Arbeit wird der Einsatz von Positronenemittern zur Bestimmung der Dichte eines zweiphasigen Mediums beschrieben. Zur Messung wird die Dichteabhängigkeit der Positronenreichweite ausgenutzt. Die Realisierbarkeit des Verfahrens wird zunächst in einer Computersimulation geprüft. Danach werden Experimente an einem hochauflösenden PET-Scanner vorgestellt. Bei diesen Experimenten wird die Dichteabhängigkeit der Reichweite von Positronen anhand von Modellmedien aus festen Schaumstoffen untersucht. Dabei werden die in der Computersimulation erzielten Ergebnisse bestätigt. Aus den experimentellen Ergebnissen wird ein Modell zur Beschreibung der Abnahme der Koinzidenzrate in Abhängigkeit von der Entfernung des Detektors von der Positronenquelle und der Mediendichte entwikkelt. Auf der Basis des Modells erfolgt die Konzipierung einer für die Dichtemessung optimierten Detektoranordnung. Die Funktionsweise dieses Detektorsystems wird in Form technischer Unterlagen und experimenteller Ergebnisse beschrieben. Mit dem optimierten Detektorsystem werden die Untersuchungen an den Modellmedien nochmals durchgeführt, wobei die bisherigen Ergebnisse bestätigt werden. Das beschriebene Meßverfahren dient der Bestimmung der mittleren Dichte in einem überwiegend gasförmigen Medium, wobei eine Mittelwertbildung über das Meßvolumen erfolgt. Das Verfahren kombiniert die Vorteile bekannter densitometrischer Meßmethoden auf der Basis einer Schwächung von Strahlung, indem die hohe Dichtesensitivität der Positronenstrahlung mit der relativ geringen Absorption der energiereichen Annihilationsquanten kombiniert wird.
|
44 |
Desempenho de gotejadores operando com percolado de aterro sanitário diluído sob pressões de serviço / Emitter performance operating with leachate landfill diluted under operating pressureVale, Hudson Salatiel Marques 29 August 2014 (has links)
Made available in DSpace on 2016-08-16T13:31:40Z (GMT). No. of bitstreams: 1
HudsonSMV_DISSERT.pdf: 1941556 bytes, checksum: 23c50ca0585d589afc959b537ecef150 (MD5)
Previous issue date: 2014-08-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The population growth and intense urbanization process, coupled with the excessive consumption of natural resources, are responsible for the exponential increase in the quantities of solid urban waste generated. The arrangement of these in landfills is a common practice; however, this provision requires environmental protection measures, including the treatment of leachate liquid. Due to the scarcity of water in semiarid of northeast, the use of this percolate in agriculture through drip irrigation systems becomes an effective strategy for this region. Considering that, the work aimed to analyze the effect of different service pressures in the performance of drip irrigation systems operating with landfill leachate diluted in water supply. To conduct the tests, it was mounted an experimental bench in the Experimental Unit of Water Reuse (EUWR), which has a total area of 793.13 m2, installed on the Zoo and Botanical Park located at
the Universidade Federal Rural do Semi-Árido (UFERSA), Mossoró Campus. The hydraulic performance and the levels of obstruction of the units irrigation applying
landfill leachate diluted in water supply were evaluated for 160 h; for that, was mounted an experimental with two factors, the first factor being the three types of emitters (G1, G2 and G3) and the second factor the four operating pressures (P1 - 70 kPa, 140 kPa -P2, P3 - 210 kPa and 280 kPa - P4) in three replicates (three lateral lines by dripper type in each irrigation unit). In every 20 hours of the system s operation it was evaluated the
CUC, CUD, CVQ, Us, Q, QR, RQR, APQ and RPQ. The data were submitted to analysis of simple and multiple regression and parametric test of Pearson correlations.
The results evidenced that the formation of biofouling resulting from the interaction between the physical, chemical and biological agents occasioned to partial and total clogging of the drippers and consequently reducing in the hydraulic performance of irrigation units which operate with landfill leachate diluted in water supply. The greater susceptibility to clogging was observed for the dripper G2, operating at service pressure P1 (70 kPa). The dripper G3 operating at pressures of service P1 (70 kPa) and P2 (140 kPa) were the combinations that best attenuated clogging. The empirical models null, linear and square root were the best fit to the relation between the variables of hydraulic performance and operation time of units irrigation, for the combinations between types
of drippers and service pressures of units irrigation / O crescimento populacional e o intenso processo de urbanização, aliado ao consumo exagerado dos recursos naturais, são responsáveis pelo aumento exponencial das
quantidades geradas de resíduos sólidos urbanos. A disposição destes em aterros sanitários é prática comum; entretanto, esta disposição requer medidas de proteção
ambiental, incluindo o tratamento do líquido percolado. Em virtude da escassez de água no semiárido nordestino, a utilização deste percolado na agricultura via sistemas de
irrigação por gotejamento torna-se uma estratégia eficaz para essa região. Diante do exposto, o trabalho objetivou analisar o efeito de distintas pressões de serviço no
desempenho de sistemas de irrigação por gotejamento operando com percolado de aterro sanitário diluído em água de abastecimento. Para a condução dos ensaios,
montou-se uma bancada experimental na Unidade Experimental de Reuso de Água (UERA), a qual apresenta uma área de 793,13 m2, instalada no Parque Zoobotânico da Universidade Federal Rural do Semi-Árido (UFERSA), Campus Mossoró. O desempenho hidráulico e os níveis de obstrução das unidades de irrigação aplicando percolado de aterro sanitário diluído em água de abastecimento foram avaliados durante 160 h; para isso, montou-se um experimento com dois fatores, sendo o primeiro fator os
três tipos de gotejadores (G1, G2 e G3) e o segundo fator as quatro pressões de serviço (P1 - 70 kPa, P2 - 140 kPa, P3 - 210 kPa e P4 - 280 kPa) em três repetições (três linhas laterais por tipo de gotejador em cada unidade de irrigação). A cada 20 h de operação do sistema avaliou-se o CUC, CUD, CVQ, Us, Q, QR, RQR, RPQ e APQ. Os dados foram submetidos às análises de regressão simples e múltipla e teste de correlações paramétricas de Pearson. Os resultados evidenciaram que a formação de bioincrustação resultante da interação entre os agentes físico-químicos e biológicos ocasionou entupimento parcial e total dos gotejadores e, consequentemente, redução no
desempenho hidráulico das unidades de irrigação que operaram com percolado de aterro sanitário diluído em água de abastecimento. A maior suscetibilidade ao entupimento foi verificada para o gotejador G2, operando na pressão de serviço P1 (70 kPa). O gotejador
G3 operando nas pressões de serviço P1 (70 kPa) e P2 (140 kPa) foram as combinações que melhor atenuaram o entupimento. Os modelos empíricos nulo, linear e raiz
quadrada foram os que melhor se ajustaram à relação entre as variáveis de desempenho hidráulico e o tempo de operação das unidades de irrigação, para as combinações entre tipos de gotejadores e pressões de serviço das unidades de irrigação
|
45 |
Improvement of Structured Light Systems Using Computer Vision TechniquesYaan Zhang (8781872) 02 May 2020 (has links)
<div>
<div>
<div>
<p>In this thesis work, we propose computer vision techniques for 3D reconstruction and
object height measurement using a single camera and multi-laser emitters, which have an
intersection on the projected image plane. Time-division and color division methods are first
investigated for our structured light system. Although the color division method offers better
accuracy for object height measurement, it requires the laser emitters equipped with different
color lights. Furthermore, the color division method is sensitive to light exposure in the
measurement environment. Next, a new multi-level random sample consensus (MLRANSAC)
algorithm has been developed. The proposed MLRANSAC method not only offers high accuracy
for object height measurement but also eliminates the requirement for the laser emitters with
different colors. Our experiment results have validated the effectiveness of the MLRANSAC
algorithm.
</p>
</div>
</div>
</div>
|
46 |
Methodische Untersuchungen zum Einsatz von Positronenemittern für die Dichtebestimmung in leichten MedienHensel, Frank January 1999 (has links)
In der vorliegenden Arbeit wird der Einsatz von Positronenemittern zur Bestimmung der Dichte eines zweiphasigen Mediums beschrieben. Zur Messung wird die Dichteabhängigkeit der Positronenreichweite ausgenutzt. Die Realisierbarkeit des Verfahrens wird zunächst in einer Computersimulation geprüft. Danach werden Experimente an einem hochauflösenden PET-Scanner vorgestellt. Bei diesen Experimenten wird die Dichteabhängigkeit der Reichweite von Positronen anhand von Modellmedien aus festen Schaumstoffen untersucht. Dabei werden die in der Computersimulation erzielten Ergebnisse bestätigt. Aus den experimentellen Ergebnissen wird ein Modell zur Beschreibung der Abnahme der Koinzidenzrate in Abhängigkeit von der Entfernung des Detektors von der Positronenquelle und der Mediendichte entwikkelt. Auf der Basis des Modells erfolgt die Konzipierung einer für die Dichtemessung optimierten Detektoranordnung. Die Funktionsweise dieses Detektorsystems wird in Form technischer Unterlagen und experimenteller Ergebnisse beschrieben. Mit dem optimierten Detektorsystem werden die Untersuchungen an den Modellmedien nochmals durchgeführt, wobei die bisherigen Ergebnisse bestätigt werden. Das beschriebene Meßverfahren dient der Bestimmung der mittleren Dichte in einem überwiegend gasförmigen Medium, wobei eine Mittelwertbildung über das Meßvolumen erfolgt. Das Verfahren kombiniert die Vorteile bekannter densitometrischer Meßmethoden auf der Basis einer Schwächung von Strahlung, indem die hohe Dichtesensitivität der Positronenstrahlung mit der relativ geringen Absorption der energiereichen Annihilationsquanten kombiniert wird.
|
47 |
Spectral features of Pb-related color centers in diamond: a systematic photoluminescence characterizationTchernij, Sviatoslav Ditalia, Corte, Emilio, Lühmann, Tobias, Traina, Paolo, Pezzagna, Sébastien, Degiovanni, Ivo Pietro, Provatas, Georgios, Moreva, Ekaterina, Meijer, Jan, Olivero, Paolo, Genovese, Marco, Forneris, Jacopo 02 May 2023 (has links)
We report on the systematic characterization of the optical properties of diamond color centers
based on Pb impurities. An ensemble photoluminescence analysis of their spectral emission was
performed at different excitation wavelengths in the 405–520 nm range and at different
temperatures in the 4–300 K range. The series of observed spectral features consist of different
emission lines associated with Pb-related defects. Finally, a room-temperature investigation of
single-photon emitters under 490.5 nm laser excitation is reported, revealing different spectral
signatures with respect to those already reported under 514 nm excitation. This work represents a
substantial progress with respect to previous studies on Pb-related color centers, both in the
attribution of an articulated series of spectral features and in the understanding of the formation
process of this type of defect, thus clarifying the potential of this system for high-impact
applications in quantum technologies.
|
48 |
Acceleration of Reverse Intersystem Crossing in Purely Organic Emitters and its Application to Hyperfluorescence Systems / 純有機発光材料における逆項間交差の高速化とHyperfluorescence系への応用Ren, Yongxia 25 September 2023 (has links)
京都大学 / 新制・課程博士 / 博士(工学) / 甲第24903号 / 工博第5183号 / 新制||工||1989(附属図書館) / 京都大学大学院工学研究科分子工学専攻 / (主査)教授 梶 弘典, 教授 関 修平, 教授 寺村 謙太郎 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM
|
49 |
Optical and electrical properties of compound and transition metal doped compound semiconductor nanowiresRamanathan, Sivakumar 11 February 2009 (has links)
Nanotechnology is the science and engineering of creating functional materials by precise control of matter at nanometer (nm) length scale and exploring novel properties at that scale. It is vital to understand the quantum mechanical phenomena manifested at nanometer scale dimensions since that will enable us to precisely engineer quantum mechanical properties to realize novel device functionalities. This dissertation investigates optical and electronic properties of compound and transition metal doped compound semiconductor nanowires with a view to exploiting them for a wide range of applications in semiconductor electronic and optical devices. In this dissertation work, basic concepts of optical and electronic properties at low dimensional structures will be discussed in chapter 1. Chapter 2 discusses the nanofabrication technique employed to fabricate highly ordered nanowires. Using this method, which is based on electrochemical self-assembly techniques, we can fabricate highly ordered and size controlled nanowires and quantum dots of different materials. In Chapter 3, we report size dependent fluorescence spectroscopy of ZnSe and Mn doped ZnSe nanowires fabricated by the above method. The nanowires exhibit blue shift in the emission spectrum due to quantum confinement effect, which increases the effective bandgap of the semiconductor. We found that the fluorescence spectrum of Mn doped ZnSe nanowires shows high luminescence efficiency, which seems to increase with increasing Mn concentration. These results are highly encouraging for applications in multi spectral displays. Chapter 4 investigates field emission results of highly ordered 50 nm tapered ZnO nanowires that were also fabricated by electrochemical self-assembly. Subsequent to fabrication, the nanowires tips are exposed by chemical etching which renders the tips conical in shape. This tapered shape concentrates the electric field lines at the tip of the wires, and that, in turn, increases the emission current density while lowering the threshold field for the onset of field emission. Measurement of the Fowler-Nordheim tunneling current carried out in partial vacuum indicates that the threshold electric field for field emission in 50-nm diameter ZnO nanowires is 15 V/µm. In this study we identified the key constraint that can increase the threshold field and reduce emission current density. In Chapter 5 we report optical and magnetic measurement of Mn-doped ZnO nanowires. Hysterisis measurements carried out at various temperatures show a ferromagnetic behavior with a Curie temperature of ~ 200 K. We also studied Mn-doping of the ZnO nanowires. The room temperature fluorescence spectroscopy of Mn-doped ZnO nanowires shows a red-shift in the spectra compared to the undoped ZnO nanowires possibly due to strain introduced by the dopants in the nanowires. Finally, in Chapter 6, we report our study of the ensemble averaged transverse spin relaxation time (T2*) in InSb thin films and nanowires using electron spin resonance (ESR) measurement. Unfortunately, the nanowires contained too few spins to produce a detectable signal in our apparatus, but the thin films contained enough spins (> 109/cm2) to produce a measurable ESR signal. We found that the T2* decreases rapidly with increasing temperature between 3.5 K and 20 K, which indicates that spin-dephasing is primarily caused by spin-phonon interactions.
|
50 |
Recherche de galaxies avec un grand décalage spectral vers le rouge (z=7.7) par imagerie en bande étroiteClement, Benjamin 21 December 2011 (has links)
Briser la frontière observationnelle de l’Univers lointain suscite de nombreux axes de recherches dans la cosmologie moderne. Exigeantes par la sensibilité demandée, ces observations constituent aussi bien un défi technologique pour les prochaines générations d’instruments qu’une étape nécessaire à la compréhension des différentes étapes d’évolution de l’Univers. Une des étapes importantes est la réionisation du milieu intergalactique, époque charnière marquant la fin des “Âges Sombres”. Déterminer quand et comment ce processus s’est déroulé et quelles ont été les sources l’ayant déclenché et entretenu sont les principales questions motivant ces recherches. Les travaux présentés dans cette thèse participent à l’effort de la communauté scientifique internationale dans la caractérisation de l’histoire de l’époque de la réionisation en recherchant des galaxies à grand décalage spectral vers le rouge (redshift). Après un panorama complet des contraintes observationnelles actuelles sur l’époque de la réionisation, sont ensuite présentés les deux projets ayant fournis les données constituant la matière première de cette analyse. En utilisant une même technique d’imagerie en bande étroite dans le domaine de longueurs d’onde proche-infrarouge, des observations avec l’instrument WIRCAM (CFHT) et d’autres avec l’instrument HAWK-I (VLT) ont permis d’établir des contraintes robustes sur la fonction deluminosité des Emetteurs Lyman-α au redshift z = 7.7. A l’occasion de la présentation du second projet, la problématique de la stratégie observationnelle est abordée, notamment via l’utilisation des amas de galaxies comme lentilles gravitationnelles amplifiant le flux des sources d’arrière-plan. L’absence de confirmation spectroscopique des Emetteurs Lyman-– sélectionnés durant l’analyse des données WIRCAM et l’absence de candidats dans le sondage HAWK-I suggèrent une évolution de la fonction de luminosité des Emetteurs Lyman-– entre les redshifts z = 6.5, telle quedéterminée dans d’autres études, et z = 7.7. La tendance de cette évolution, en luminosité ou en densité de galaxies, ne peut pas encore être déterminée compte tenu de la variabilité des résultats obtenus à plus bas redshift. Si cette évolutions’effectuait en luminosité, ce pourrait être le signe d’une augmentation de l’opacité du milieu intergalactique au rayonnement Lyman-α causée par une plus importante fraction d’hydrogène neutre, ce qui est une signature attendue de la réionisation. / Breaking through the observational frontier of the distant universe motivates numerous scientific cases in modern cosmology. Demanding by the required sensitivity, high-redshift observations provide both a technological challenge for next generation instruments and a necessary step toward the understanding of cosmic evolution. One critical epoch is the reionization of the intergalactic medium bringing to light the end of the so-called “Dark Ages”. Determine when and how this process took place and what were the sources that started and maintained the reionization are the mainquestions motivating this research. The work presented in this thesis contributes to the effort of the internationalscientific community in characterizing the reionization epoch history by searching for galaxies at high redshift. First, I describe the current observational constraints in a comprehensive chapter. Then the two datasets used in that work are presented. From narrow-band observations in the near-infrared with WIRCAM at the CFHT and HAWK-I at the VLT, I put strong constraints on the luminosity function of Lyman-α Emitters at z = 7.7. The best strategy for this type of survey is discussed, in particular with the use of massive galaxy clusters acting as gravitational lenses that amplify the flux from background sources. The lack of spectroscopic confirmation of candidates found with WIRCAM and the lack of candidates found with HAWK-I suggest an evolution of the luminosity function from z = 6.5. This evolution could be either in luminosity or in number density but somewhat discrepant results at lower redshift prevent any definitive answer to this question. If the evolution was mostly in luminosity, it could be interpreted as an increase in the opacity of the intergalactic medium caused by an increased fraction of neutral hydrogen, which is an expected signature of reionization.
|
Page generated in 0.0826 seconds