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1
Contie, Yohan. "Synthèse et réactivité de silylènes stables Si-fonctionnalisés (-Si-H, -Si-Cl, -Si-SnR3, Si-SiR3)." Toulouse 3, 2012. http://thesesups.ups-tlse.fr/1832/.
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L'objectif principal de cette thèse est l'étude de silylènes stabilisés par coordination d'une phosphine. Cette étude porte plus particulièrement sur l'influence de la nature du ligand et du substituant porté par l'atome de silicium sur les propriétés de ces espèces. Le premier chapitre est une étude bibliographique qui permet de faire le point sur les différents modes de stabilisation des silylènes, avec une attention particulière portée aux complexes silylènes-base de Lewis. Le deuxième chapitre concerne la synthèse du premier hydrogénosilylène stabilisé par un ligand phosphine. En présence d'une oléfine, il donne lieu à une réaction d'hydrosilylation dans des conditions douces et sans catalyseur. Cette réaction d'insertion migratoire a été extrapolée à deux autres types de silylènes fonctionnalisés par des groupements silylés et stannylés. Il est intéressant de noter que dans le cas des silylènes stannylés, la réaction d'insertion est réversible dans des conditions douces. Cette réaction de Béta-élimination d'alcène sur le centre silicié démontre que les complexes de silylènes préparés présentent un comportement similaire à celui des complexes de métaux de transition. Le troisième chapitre est consacré à l'étude de la dimérisation des complexes de silylènes, en jouant sur l'encombrement stérique des substituants portés par l'azote et/ou le phosphore. La diminution de la protection cinétique du centre Si(II) conduit à la formation de silylènes moins stables qui se dimérisent via un processus original, impliquant une activation réversible d'une liaison Si-H ou Si-Cl. Dans le quatrième chapitre est développée l'étude de la réactivité d'un C-phosphino-silyne. L'implication du groupement phosphino dans la stabilisation de la triple liaison SiC, induit un comportement de dipôle-1,3, qui a été mis à profit dans des réactions de cycloaddition [3+2] avec le benzonitrile. Les cycloadduits obtenus présentent une structure électronique similaire aux carbodiphosphoranes cycliques avec un caractère nucléophile très importantThe main objective of this thesis concerns the study of silylenes stabilized by coordination of a phosphine ligand. Particularly, this study is focused on the influence of the nature of the ligand and the silicon substituents on the properties of these phosphine-silylene complexes. The first part of this thesis is a review concerning the different modes known about the stabilization of the silylene moiety, with a particular focus on silylene-Lewis base complexes. The second chapter deals with the first synthesis of phosphine-stabilized hydrogenosilylenes. In the presence of an olefin, an original hydrosilylation reaction was observed in mild conditions and without any catalyst. Functionalized silyl- and stannyl-silylenes also react readily with olefins through an insertion migration process, which is perfectly reversible in the case of the stannylsilylene derivative. This Béta-elimination reaction of the olefin at the silicon center demonstrates that phosphine-stabilized silylenes can behave in some cases like transition metal complexes. The third chapter is devoted to the study of the dimerization process of phosphine-silylene complexes, playing on the steric hindrance of nitrogen and phosphorus substituents. A lower kinetic protection of the Si(II) center led to unstable silylenes, which dimerise through an original and reversible Si-H or Si-Cl bond activation. In the fourth chapter is reported a study concerning the reactivity of a C-phosphino-silyne. Due to the implication of the phosphino group on the stabilization of the SiC-triple bond, this molecule can behave as a 1,3-dipole, and reacts readily with benzonitrile through a [3+2] cycloaddition process. The corresponding cycloadducts can be related to cyclic carbodiphosphoranes, particularly concerning the electronic properties, and therefore they present a strong nucleophilic character
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Hadley, M. J. "Scanning tunnelling microscopy of Si(111), Pb-Si(111) and Si(113)." Thesis, University of York, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316178.
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Dufauquez, Christophe. "Production de particules chargées légères et multiplicités neutroniques associées dans les réactions p+(nat)Si et alpha+(nat)Si de 20 à 65 MeV." Université catholique de Louvain, 2005. http://edoc.bib.ucl.ac.be:81/ETD-db/collection/available/BelnUcetd-06012006-114210/.
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Cette dissertation présente les résultats des mesures des sections efficaces inclusives de production des particules chargées légères (protons, deutons, tritons, 3He, alpha, 6Li, 7Li et 7Be) ainsi que les multiplicités neutroniques associées, relevés lors des réactions nucléaires induites par protons et alpha sur une cible de natSi. Ces mesures ont été réalisées auprès du cyclotron CYCLONE de Louvain-la-Neuve aux énergies de 26.5, 48.5 et 62.9 MeV pour les réactions (p, (nat)Si) et de 25.4, 45.5 et 57.8 MeV pour les réactions (alpha, (nat)Si). Le système de détection, original dans sa conception, a été assuré par 15 télescopes constitués d'un assemblage de jonctions silicium et de scintillateurs inorganiques CsI assurant une couverture angulaire de 0 à 360°. Toutes les particules chargées étudiées dans ce travail ont été identifiées sur base de l'information de leurs pertes d'énergie dans les différentes jonctions et par la technique de l'analyse en forme des signaux lumineux issus des CsI. La détection des neutrons a été assurée par le multi-détecteur à neutrons DEMON constitué de 81 scintillateurs organiques liquides. Ces neutrons ont été identifiés par la technique de l'analyse en forme du signal lumineux. L'énergie des neutrons a été déduite par mesure de leur temps de vol. Les distributions angulaires des pics élastiques et inélastiques de la diffusion des protons et des alpha sur le 28Si ont été confrontées aux prédictions des modèles Optique, DWBA et Canaux Couplés, utilisant différents potentiels optiques. Une comparaison des résultats expérimentaux avec ceux déjà publiés sur des réactions similaires ou comparables a également fait l'objet de ce travail. De plus, les résultats ont été confrontés à ceux des prédictions des codes de simulation GNASH et TALYS. Une attention particulière a été portée aux prédictions du code TALYS. Enfin, ce travail fournit une très large et très complète base de nouvelles données expérimentales qui constitue un atout majeur et bénéfique aussi bien dans l'amélioration des codes théoriques de simulation de ce type de réactions que dans les prédictions des dégâts radiatifs induits par les différents rayonnements ionisants dans les semi-conducteurs, en général, et les composants électroniques, en particulier.
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Yi, Mi-Kyung. "Hermeneutique et psychanalyse si proches. . . Si etrangeres." Paris 7, 1998. http://www.theses.fr/1998PA070015.
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Notre travail propose une confrontation entre hermeneutique et psychanalyse. Bien que l'une et l'autre recourent a l'interpretation, notre these est que la methode d'investigation freudienne est une + anti-hermeneutique ;. La signification de cet "anti-" qui semble renvoyer d'abord a la difference technique d'interpretation est a elucider en consideration de deux autres implications de l'hermeneutique en psychanalyse : l'hermeneutique, en tant que logique de la recherche et l'hermeneutique, en tant que theorie philosophique de la comprehension humaine. La premiere partie de notre travail s'attache a une lecture de quelques auteurs fondateurs de l'hermeneutique philosophique, comme schleiermacher, dilthey, heidegger et gadamer. Elle a pour fil conducteur la question de l'alterite que nous avancons comme le ressort de la pensee hermeneutique. Notre etude de differentes theories de la comprehension au cours de l'histoire de l'hermeneutique tente de mettre en evidence un certain oubli de la dimension du message constitutive de la naissance de l'hermeneutique. La seconde partie est consacree au debat en psychanalyse, autour du dit + tournant hermeneutique ;. Notre travail tache d'en examiner le caractere de renouveau, a travers une etude critique de differents auteurs qui reinterpretent la doctrine psychanalytique dans une perspective hermeneutique : p. Ricoeur, s. Viderman, d. Spence et r. Schafer. Vient ensuite l'etude de la theorie de c. G. Jung, premier a se reclamer de l'hermeneutique. Le troisieme chapitre revient a freud, pour etablir, s'inspirant des travaux de jean laplanche, notamment sa propre conception de la seduction, de la traduction et de l'interpretation, en quoi la psychanalyse ne peut se definir que comme etrangere a tout mouvement hermeneutique, precisement pour les memes raisons qui obligeaient freud a opposer sa methode a toutes les formes de psychosyntheseOur research propose a confrontation between hermeneutics and psychoanalysis. Although one and the other appeal to the interpretation, our thesis is that the freudian method of investigation is + anti- hermeneutic ;. The meaning of this + anti-; which refer to the technical difference of interpretation is to elucidate considering two other involvements of hermeneutics in psychoanalysis: hermeneutics, as the research logic and as the philosophical theory of human understanding. The first part of our study apply to read some founders of philosophical hermeneutics, as schleiermacher, dilthey, heidegger and gadamer. This reading is guided by the question of otherness which we put forward as the motor of hermeneutic mouvement. Our study of different hermeneutic theories of understanding tries to underscore the dimension of message constituent of the birth of hermeneutics but forgetted today. The second part of our research is devoted to the debate in psychoanalysis, around the + hermeneutic turn ;. To examinate the caracteristic of revival of this turn, we apply to study differents authors who reinterpret the psychoanalysis in a hermeneutic point of view : p. Ricoeur, s. Viderman, d. Spence and r. Schafer. And then comes the examination of the jungian method, first explicit hermeneutic version of psychoanalysis. At last, we return to freud to establish, inspired by the work of laplanche, in particular, by his conception of seduction, translation and interpretation, why psychoanalysis is defined as stranger to any hermeneutic mouvement, exactely for the same reasons why freud was compelled to define his method in contrast to all psychosynthesis
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Левіцький, Анатолій Миколайович. "Структура та властивості сплавів систем Nb-Si-B, Nb-Si-Cr, Nb-Si-Ti, Nb-Si-Mo для високотемпературних застосувань." Master's thesis, КПІ ім. Ігоря Сікорського, 2019. https://ela.kpi.ua/handle/123456789/31364.
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Об’єкт дослідження: сплави систем Nb-Si-(B, Cr, Mo, Ti) ат. %:
Nb-25Si-13B, Nb-Si-25Cr, Nb-6Si-30Cr, Nb-6Si-35Cr, Nb-20Si-2Mo, Nb-20Si-4Mo, Nb-20Si-6Mo, Nb-20Si-22Ti, Nb-20Si-24Ti, одержані електронно-променевим спіканням.
Метою роботи є вивчення структури та властивостей евтектичних сплавів систем Nb-Si-(B, Cr, Mo, Ti), одержаних електронно-променевим оплавленням.
Методи дослідження та апаратура: отримання сплавів систем
Nb-Si-(B, Cr, Mo, Ti) здійснювалось в установці ЭЛА-6. За допомогою комплексу високоінформативних методів фізичного матеріалознавства (електронної мікроскопії, мікрорентгеноспектрального аналізу) досліджено мікро- та макроструктуру, хімічний склад фазових складових сплавів систем
Nb-Si-(B, Cr, Mo, Ti). Також виміряна мікротвердість та тріщиностійкість на мікротвердомірі ПМТ-3.The object of study: the alloys of the system Nb-Si-(B, Cr, Mo, Ti) at. %: Nb-25Si-13B, Nb-Si-25Cr, Nb-6Si-30Cr, Nb-6Si-35Cr, Nb-20Si-2Mo, Nb-20Si-4Mo, Nb-20Si-6Mo, Nb-20Si-22Ti, Nb-20Si-24Ti obtained by electron beam sintering. The purpose of the work is to study the structure and properties of alloys of the Nb-Si-(B, Cr, Mo, Ti) system obtained by electron beam sintering. Research methods and equipment: the alloys of system Nb-Si-(B, Cr, Mo, Ti) were obtained by ELA-6. The micro- and macrostructure, the chemical composition of the phase components of the resulting Nb-Si-(B, Cr, Mo, Ti) alloys, was studied using a set of highly informative methods of physical material science (electron microscopy, chemical analysis). It was measured is microhardness and crack resistance.
Объект исследования: сплавы систем Nb-Si-(B, Cr, Mo, Ti) ат. %: Nb-25Si-13B, Nb-Si-25Cr, Nb-6Si-30Cr, Nb-6Si-35Cr, Nb-20Si-2Mo, Nb-20Si-4Mo, Nb-20Si-6Mo, Nb-20Si-22Ti, Nb- 20Si-24Ti, полученные электронно-лучевым оплавлением. Целью работы является изучение структуры и свойств эвтектических сплавов систем Nb-Si-(B, Cr, Mo, Ti), полученных электронно-лучевым оплавлением. Методы исследования и аппаратура: получение сплавов систем Nb-Si-(B, Cr, Mo, Ti) осуществлялось в установке Эла-6. С помощью комплекса высокоинформативных методов физического материаловедения (электронной микроскопии, микрорентгеноспектрального анализа) исследованы микро- и макроструктура, химический состав фазовых составляющих сплавов систем Nb-Si-(B, Cr, Mo, Ti). Также измерена микротвердость и трещиностойкость на Микротвердомере ПМТ-3.
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Mezger, Nathalie. "L'adénome hépathique : une pathologie si simple, si bénigne ? /." Genève : [s.n.], 2009. http://opac.nebis.ch/cgi-bin/showAbstract.pl?sys=000289145.
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Ho, Catherina R. "Heterogeneous nucleation of Si in Al-Si alloys." Thesis, University of Oxford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386591.
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Salman, Fatma. "EXPERIMENTAL STUDY OF PROFILES OF IMPLANTED SPECIES INTO SEMICONDUCTOR MATERIALS USING SECONDARY ION MASS SPECTROMETRY." Doctoral diss., University of Central Florida, 2007. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3056.
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ABSTRACT The study of impurity diffusion in semiconductor hosts is an important field that has both fundamental appeal and practical applications. Ion implantation is a good technique to introduce impurities deep into the semiconductor substrates at relatively low temperature and is not limited by the solubility of the dopants in the host. However ion implantation creates defects and damages to the substrate. Annealing process was used to heal these damages and to activate the dopants. In this study, we introduced several species such as alkali metals (Li, Na, K), alkali earth metals (Be, Ca,), transition metals (Ti, V, Cr, Mn) and other metals (Ga, Ge) into semiconductor substrates using ion implantation. The implantation energy varies form 70 keV to 200 keV and the dosages vary between ~ 1.0x1012 and ~5.0x1015 atoms/cm2. The samples are annealed at different temperatures from 300°C to 1000°C and for different time intervals. The redistribution behaviors of the implanted ions are studied experimentally using secondary ion mass spectrometry (SIMS). We observed some complex distribution behaviors due to the defects created during the process of ion implantation. The diffusivities of some impurities are calculated and compared to previous data. It was found that the diffusivities of implanted impurities is related to the dosages, annealing temperatures and the defects and damages caused by ion implantation. Additionally, as we go from one type of semiconductor to another, the diffusion behavior of the impurities shows a different trend.Ph.D.
Department of Physics
Sciences
Physics PhD
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Hoffmann, Volker. "Innere Photoemission in Au/Si und CoSi2/Si Heterostrukturen." [S.l. : s.n.], 1998. http://darwin.inf.fu-berlin.de/1998/2/index.html.
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Hugunin, James Jeffrey. "The superconductor/semiconductor interface of V₃Si and Si." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/11862.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1995.Includes bibliographical references (leaves 43-45).
by James Jeffrey Hugunin.
M.S.
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Yaacoub, Nader. "Nouveaux états du Si dans les multicouches Co/Si." Université Louis Pasteur (Strasbourg) (1971-2008), 2007. https://publication-theses.unistra.fr/public/theses_doctorat/2007/YAACOUB_Nader_2007.pdf.
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Nous avons étudié les propriétés structurales et physiques des multicouches Co/Si déposées par pulvérisation cathodique à 90 K dans le but de limiter la diffusion aux interfaces. Nous avons obtenu des multicouches très bien cristallisées quoique polycristallines, formées de très grands grains > 300 nm et un mélange limité par rapport à celui des multicouches déposées à 300 K. Cela nous a permis d’observer des phénomènes physiques nouveaux, originaux et spectaculaires dans ces multicouches : (1) Oscillation du couplage d’échange magnétique en accord avec les calculs ab initio, (2) Oscillation de la résistance de faible à forte et (3) Oscillation de la rugosité de l’interface, en fonction de l’épaisseur de Si. La période des ces oscillations, bien corrélées entre elles, est courte de l’ordre de 0. 4 nm soit 2 ML. Cela nous a conduit de proposer une interprétation commune de ces résultats, basé sur le passage périodique au niveau de Fermi d’un état de puits quantique dans la couche de SiIn this work we studied the structural and physical properties of the Co/Si multilayers deposited by sputtering at 90 K with the aim of limiting the interdiffusion at interfaces. We have obtained very well crystallized multilayers although polycristalline, formed of very big grains > 300 nm with limited interfacial mixing as compared to that of multilayers deposited at 300 K. It allowed us to observe new, original and spectacular physical phenomena in these multilayers: (1) Oscillation of the interlayer exchange coupling in agreement with ab-initio calculations, (2) Oscillation of the multilayer resistance from weak to strong and (3) Oscillation of the roughness of the interface, according to the thickness of Si. The period of these oscillations, which are well correlated between them, is short of the order of 0. 4 nm (2 ML). This led to us to propose a common interpretation of these results, based on the periodic passage at the Fermi level of a quantum well state in the Si layer
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Karp, Christoph D. Lewis Nathan Saul. "Photoelectrochemistry of Si/polymer and Si/metal/solution interfaces /." Diss., Pasadena, Calif. : California Institute of Technology, 1995. http://resolver.caltech.edu/CaltechETD:etd-10262007-085203.
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Yaacoub, Nader Panissod Pierre. "Nouveaux états du Si dans les multicouches Co/Si." Strasbourg : Université Louis Pasteur, 2007. http://eprints-scd-ulp.u-strasbg.fr:8080/823/01/YAACOUB_Nader_2007.pdf.
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Meitzner, Karl. "Heterojunction-Assisted Impact Ionization and Other Free Carrier Dynamics in Si, ZnS/Si, and ZnSe/Si." Thesis, University of Oregon, 2015. http://hdl.handle.net/1794/19294.
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With increasing global energy demand and diminishing fossil fuel supplies, the development of clean and affordable renewable energy technology is more important than ever. Photovoltaic devices harvest the sun’s energy to produce electricity and produce very little pollution compared to nonrenewable sources. In order to make these devices affordable, however, technological advances are required.
In this dissertation a novel photovoltaic device architecture that is designed to enhance sunlight-to-electricity conversion efficiency of photovoltaics is proposed and demonstrated. The increase in efficiency arises due to enhancement of the internal quantum efficiency of photoexcitation in the semiconductor absorber. In other words, the probability that the absorption of a single photon will produce two or more electron-hole pairs, instead of just one, is increased. This occurs through the process of impact ionization, by which a highly excited charge carrier (via absorption of a high energy photon) relaxes by excitation of a second electron-hole pair. The result is an increased photocurrent, and efficiency, of the photovoltaic device.
Using thin films of ZnS on Si substrates, we demonstrate that the probability of impact ionization is enhanced at the (unbiased) heterojunction between these layers. The magnitude of enhancement depends on material properties, including crystallinity of the ZnS film as well as concentration of oxygen (impurity) at the interface. Thin films of ZnSe on Si substrates do not exhibit heterojunction-assisted impact ionization, but they do display promising characteristics that make them an intriguing system for future work. The same is true for ZnS/Si materials fabricated by O2-free chemical bath deposition.
For the analysis of plain Si as well as ZnS/Si and ZnSe/Si heterostructures, we employ a novel pump-probe transient transmission and reflection spectroscopy technique. A method is demonstrated for using this technique to quantify internal quantum efficiency as well as interface recombination velocity in each of these materials. In bulk silicon, a free carrier absorption cross section that depends on free carrier concentration (above 1018 cm-3) is observed and the relationship is quantified.
This dissertation includes unpublished and previously published co-authored material.
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Chen, Chia-Wei. "Low cost high efficiency screen printed solar cells on Cz and epitaxial silicon." Diss., Georgia Institute of Technology, 2016. http://hdl.handle.net/1853/54968.
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The objective of this research is to achieve high-efficiency, low-cost, commercial-ready, screen-printed Silicon (Si) solar cells by reducing material costs and raising cell efficiencies. Two specific solutions to material cost reduction are implemented in this thesis. The first one is low to medium concentrator (2-20 suns) Si solar cells. By using some optics to concentrate sunlight, the same amount of output power can be achieved with cell area reduced by a factor equal to the concentration ratio. Since the cost of optics is less than the semiconductor material, electricity price from the concentrator photovoltaics (PV) system is therefore reduced. The second solution is the use of epitaxially grown Si (epi-Si) wafers. This epi-Si technology bypasses three costly process steps (the need for polycrystalline silicon feedstock, ingot growth, and wafer slicing) compared to the traditional Si wafer technology and therefore reduces the material cost by up to 50% in a finished PV module. In addition, high efficiency Si solar cells with reduced metal contact recombination are studied and modeled by implementation of passivated contacts composed of tunnel oxide, n+ polycrystalline Si and metal on top of n-type Si absorber to reduce the cost ($/Wp) of PV module.
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Naftel, Steven. "Interactions of transition metals with silicon(100), the Ni-Si, Co-Si and Au/Si(100) systems." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0008/NQ42546.pdf.
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Gadea, Gerard. "Integration of Si/Si-Ge nanostructures in micro-thermoelectric generators." Doctoral thesis, Universitat de Barcelona, 2017. http://hdl.handle.net/10803/459243.
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Silicon and silicon-germanium nanostructures were grown, integrated, optimized and characterized for their application in thermoelectric generation. Specifically two kinds of nanostructures were worked: silicon and silicon-germanium nanowire arrays (Si/Si-Ge NW) and polycrystalline silicon nanotube fabrics (pSi NT).
The results are dived in four chapters. Chapters 3, 4 and 5 deal with Si/Si-Ge NWs, while chapter 6 presents the pSi NT fabrics.
In Chapter 3 the growth and integration of Si/Si-Ge NWs was studied, in order to optimize their properties for thermoelectric application in micro-thermoelectric generators (µTEG). First, the methods for depositing gold nanoparticles prior to NW growth were studied. Second, the growth of NWs from the gold nanoparticles in a Chemical Vapour Deposition (CVD) process was comprehensively studied and optimized for subsequent integration of NWs in µTEGs, both of Si and Si-Ge. All important properties – NW length, diameter, density, doping and alignment
– could be controlled by tuning the seeding gold nanoparticles and the process conditions, namely temperature, pressure, flows of reactants and growth time. Finally, integration was demonstrated in micro-structures for thermoelectric generation and characterization. The optimization process yielded to fully integrated thermoelectric Si/Si-Ge NW arrays with diameters and densities of ~100 nm and 5 NW/µm2 respectively.
In Chapter 4 the Si NWs were thermoelectrically characterized. The Seebeck coefficient, electrical conductivity and thermal conductivity of arrays and single Si-NWs were measured in microstructures devoted to characterization comprising NWs integrated as in final µTEG application. Additionally a novel atomic force microscope based method for determination of thermal conductivity was explored. Then the results were discussed comparing them with existing literature. A ZT of 0.022 was found at room temperature, revealing an improvement of factor 2-3 with respect to bulk.
In Chapter 5 The harvesting capabilities of µTEGs with integrated Si/Si-Ge NWs was assessed. The thermal gradient and the power of the µTEGs was assessed for two generation of devices and for two thermoelectric materials, namely Si and Si-Ge NWs, which were integrated for the first time in functional generators. Also a study on heat sinking and convection effects was conducted adding insight towards further device improvement. Finally, the results were discussed and compared with literature. The maximum power densities attained were 4.5
µW/cm2 for the Si NWs and 4.9 µW/cm2 for the Si-Ge NWs while harvesting over surfaces at
350 ºC.
Chapter 6 deals with pSi NT fibers. First this new material concept and the growth route are presented, showing the fabrication steps and the control of the resulting properties by CVD method. Then the material is thermoelectrically characterized, by measuring its Seebeck coefficient and electrical and thermal conductivities up to 450 ºC. A ZT of 0.12 was found, doubling the optimally doped bulk at this temperature. Finally a proof of concept was demonstrated by assessing the thermal harvesting capabilities of the material on top of hot surfaces. A maximum of 3.5 mW/cm2 was attained at 650 ºC.Los materiales termoeléctricos permiten la conversión de calor a electricidad y viceversa. Esto permite explotar el efecto termoeléctrico en generadores termoeléctricos, capaces de extraer energía térmica de fuentes calientes y convertirla a electricidad útil. Estos generadores presentan grandes ventajas, como su falta de piezas móviles – y por ende necesidad de mantenimiento alguna – y su total escalabilidad, que permite cambiar su tamaño sin afectar su rendimiento. Esto los hace obvios candidatos para la alimentación y carga de dispositivos portátiles y situados lugares de difícil acceso. A pesar de ello, su uso no está muy extendido debido a que su relación eficiencia-coste es baja en comparación a otros métodos capaces de suplir las funciones de alimentación – como la sustitución periódica de baterías – o de conversión térmica-eléctrica – como las turbinas de vapor. Los materiales termoeléctricos suelen ser o eficientes y caros (como el Bi2Te3 usado en los módulos comerciales) o ineficientes y de bajo coste (como el silicio, barato por su abundancia ya que supone un 28% de la corteza terrestre). En este trabajo se han crecido nanostructuras de silicio y silicio-germano, con dimensiones en el orden de los 100 nm. Los nanomateriales presentan propiedades termoeléctricas mejoradas respecto a sus contrapartes macroscópicas. Gracias a la nanoestructuración pues, se ha abordado del problema de eficiencia-coste por dos vertientes: • En el caso del silicio – normalmente un mal termoeléctrico debido a su alta conductividad térmica – se ha habilitado su uso como termoeléctrico al crecerlo en forma de nanohilos cristalinos y nanotubos de silicio policristalino. • En el caso de silicio-germano – que ya es un buen termoeléctrico para uso en altas temperaturas – se ha aumentado su eficiencia aún más, creciéndolo en forma de nanohilos. Yendo más allá de la síntesis, los nanohilos de silicio/silicio-germano se han optimizado, caracterizado en integrado en gran número micro-generadores termoeléctricos de 1 mm2 de superficie, pensados para la alimentación de pequeños dispositivos y circuitos integrados. Respecto a los nanotubos de Si, estos se han obtenido en densas fibras macroscópicas aptas para su aplicación directa como generadores termoeléctricos de gran área. Cabe mencionar que ambos nanomateriales – así como los microgeneradores basados en nanohilos – fueron obtenidos mediante técnicas actualmente utilizadas para la fabricación de circuitos integrados, pensando en la escalabilidad del proceso para su aplicación. El trabajo presentado en esta tesis consiste en el crecimiento, optimización, estudio e integración de nanostructuras de Si/Si-Ge para su aplicación en generación termoeléctrica. En los Capítulos 1 y 2 se pone un marco a los materiales tratados y su aplicación y se describen los métodos utilizados, respectivamente. Los resultados se han dividido en cuatro capítulos. En los Capítulos 3, 4 y 5 se tratan los nanohilos abordando su crecimiento, caracterización y aplicación en microgeneradores, respectivamente. En el Capítulo 6 se tratan las fibras de nanotubos, integrando todo el estudio en el mismo capítulo. Finalmente en el Capítulo 7 se muestran las conclusiones, resumiendo los resultados e indicando la relevancia del trabajo.
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Milne, David Kerr. "Laser chemical vapour deposition of Si and Si-C alloys." Thesis, Heriot-Watt University, 1989. http://hdl.handle.net/10399/937.
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Nazir, Z. H. "Surface magnetism of Fe/Si(111) and Fe/Si(100)." Thesis, University of Sussex, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362272.
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Wu, Hao. "Numerical and experimental investigation of SI-HCCI-SI mode transitions." Thesis, University of Cambridge, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609143.
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You, Wenbin. "Electrical properties of Si nanocrystal films processed from Si-inks." Master's thesis, Universidade de Aveiro, 2009. http://hdl.handle.net/10773/4553.
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Mestrado em Ciência e Engenharia dos MateriaisFilmes finos de nanocristais de sílicio (Si-NCs) depositados sobre substratos flexiveis, usando tintas de sílicio, são atractivos por causa do seu potencial na utilização em dispositivos competitivos em termos de custo e versáteis taiscomo detectors e dispositivos termoeléctricos. O estudo da preparação ecomportamento eléctrico destas redes de nanocristais é fundamental paracompreender completamente o seu potencial. Em investigação anterior, filmesde Si-NCs foram depositados por spin coating sobre substratos de polimida e asua condutividade eléctrica for medida a baixa temperatura e em vácuo. Neste trabalho, baseado no processo anteriormente desenvolvido, nós estudamos a influência dos diferentes parâmetros de preparação na morfologiae optimizámo-los tais como a concrentação da tinta de Si e a velocidade derotação durante a preparação por spin coating. Além disso, investigamos as propriedades eléctricas de filmes de Si-NCs em condições ambientais e à temperatura ambiente, que é considerada umasituação mais realista, no que respeita a aplicações futuras, do que ascondições de vácuo e baixa temperatura. Especificamente, o efeito de vários processos fundamentais, tais como tratamento de superfície (erosão HF) dosSi-NCs, dopagem electrónica e iluminação na condutividade eléctrica emcondições ambientais foi investigada. Verificamos que as curvas decondutividade versus tempo (σ-t) dos filmes de Si-NCs medidas em condiçõesambientais apresentam um decaímento rápido causado pela tensão aplicada,seguida pela saturação em valores baixos. Antes do tratamento com HF, nema exposição à luz nem a dopagem tipo-p leva a uma alteração significativa da condutividade. Depois da remoção dos óxidos nativos dos Si-NCs (tratamento do filmes com HF), um forte efeito da iluminação e da dopagem tipo-p sobre a condutividade é observado, o que indica que a condução nos filmes de Si-NCs é dominada por diferentes mecanismos dependendo de os nanocristaisestarem terminados com H ou oxidados. Além disso, da comparação entremedidas eléctricas e ópticas (realizados através de espectroscopia FT-IR), concluimos que a degradação da condutividade dos filmes de Si-NCs tratado com HF que ocorreu por exposição às condições ambientais é essencialmentedevida ao crescimento de uma camada de óxido na superfície dos Si-NCs.
Thin films of silicon nanocrystals (Si-NCs) deposited onto flexible substrates using silicon inks are attractive because of their potential applications in cost efficient and versatile devices such as detectors and thermoelectric devices. Studying the assembling and electrical behaviour of these nanocrystal net-works is fundamental to understand fully their technical potential. In previous research, Si-NC films have been deposited by spin coating process onto poly-imide substrates and the electrical conductivity of the resulting films hasbeen measured at low temperature and vacuum conditions. In this work, based on the previously developed process, we have studied theinfluence of different assembling parameters on film morphology and optimized the parameters such as the ink concentration and the spin rate for the film fab-rication. Furthermore, we have investigated the electrical properties of Si-NC films at ambient atmosphere and room temperature, which is considered to be a more practical situation with regard tofuture applications than the vacuum and low temperature conditions. Specifically, the effect of several fundamental proc-esses, such as surface treatment (HF etching) of Si-NCs, electronic doping and illumination on the electrical conductivity at ambient conditions has been inves-tigated. We find that the conductivity-time curves (σ-t) of the Si-NC films measured at ambient conditions show a fast decay caused by the applied volt-age, followed by a saturation at lower levels. Before HF etching, neitherthe light exposure nor the P-doping leads to a significant change of the conductiv-ity. After removal of the native surface oxide layer of Si-NCs (by HF etching of the films), a strong effect of illumination and P-doping on the film conductivity isin turn observed, which indicates that the conduction in Si-NC films is domi-nated by different mechanisms depending on whether the nanocrystals are H-terminated or surface oxidized. Furthermore, from a comparison between elec-trical and optical measurements (carried out with FT-IR spectroscopy), we conclude that the degradation of the conductivity of HF-etched Si-NC films that occurred by exposure to ambient conditions is mainly attributed to the growth of the oxide layer on the Si-NC surface.
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Bascetta, Marco. "Eppur si muove." Universität Leipzig, 2002. https://ul.qucosa.de/id/qucosa%3A33527.
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Stulman, Timothy A. "Si Ji Tu." Bowling Green State University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1151329272.
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Netzer, Giovanni. "Si en parvis ! /." Basel : Ed. Theaterkultur Verl, 2001. http://catalogue.bnf.fr/ark:/12148/cb39077268x.
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Diss.--Philosophische Fakultät für Geschichts- und Kunstwissenschaften--München--Ludwig-Maximilians-Universität, 2001.Mention parallèle de titre ou de responsabilité : Auf in den Himmel ! : rätoromanische Dramen des 18. Jahrunderts. Bibliogr. p. 269-281.
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Resende, Mário Ferreira. "Itinerários de si." reponame:Repositório Institucional da UFSC, 2012. http://repositorio.ufsc.br/xmlui/handle/123456789/94324.
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Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Filosofia e Ciências Humanas, Programa de Pós-Graduação em Psicologia, Florianópolis, 2010Made available in DSpace on 2012-10-25T08:45:23Z (GMT). No. of bitstreams: 1 284330.pdf: 540115 bytes, checksum: 504822c492ee67b31805c95e3f591cf0 (MD5)
O presente trabalho propõe tomar o tema da identidade a partir de uma perspectiva crítica, assumindo como objeto de análise um conjunto de fragmentos colhidos numa comunidade da rede virtual de relacionamentos Orkut que propõe o debate acerca do tema da mudança. A comunidade Eu Mudei corresponde ao espaço discursivo onde se articulam os testemunhos de sujeitos, seus processos de desubjetivação e transformação, produzindo a abertura na qual é possível ver o lugar da relação com o exterior no aparentemente simples gesto de enunciação da mudança. Trabalhada na sua banalidade, e não apesar dela, a comunidade configurou-se então como o espaço em que a ambivalência da constituição do sujeito, nesse lançar-se contínuo à mudança, realiza-se, tanto na abertura ao impessoal, quanto na recondução a posições identitárias. O processo pelo qual se converte uma forma de subjetividade em outra constitui um intervalo, um hiato entre dois vir a ser subjetivos, distância entre o que deixei de ser e o que sou agora. O trânsito de uma identidade a outra expõe a sua radicalidade histórica: a constituição contingencial diante das forças positivas de seu tempo que delimita, recorta e hierarquiza as formas válidas de ser sujeito. O trabalho também buscou mostrar que esse lugar de enunciação da mudança produz movimentos outros e dá abrigo a vozes que não foram capturadas e reconduzidas a posições identitárias. Nesse caso, o gesto que nos lança ao movimento de mudança articula-se potente quando o que resta coincide com o que é suficiente para continuar. Mesmo um conceito como o de identidade, só pode apontar para o uno, para o indivisível, para a unidade, porque o seu processo de produção também já remete para o múltiplo, para o de fora, para o devir. A distância imposta pela passagem de uma posição identitária para outra é suficiente para restituir ao sujeito a sua condição de força afetada pelo mundo e de pura abertura à exterioridade. Descolada dos conteúdos das proposições, as forças singulares e nômades se dão nessa passagem, nesse salto que encontra no testemunho a possibilidade de expressão de sua potência criadora.
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Marcolin, Samuel Pereira. "Escritas de si." reponame:Repositório Institucional da UFSC, 2016. https://repositorio.ufsc.br/xmlui/handle/123456789/177342.
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Dissertação (mestrado profissional) - Universidade Federal de Santa Catarina, Centro de Ciências da Educação, Programa de Pós-Graduação em Ensino de História, Florianópolis, 2016.Made available in DSpace on 2017-07-11T04:20:59Z (GMT). No. of bitstreams: 1 346425.pdf: 609645 bytes, checksum: 4803cea3ce049b97590e03a77548a5cb (MD5) Previous issue date: 2016
Esta dissertação é o resultado de uma pesquisa realizada no Programa de Mestrado Profissional em Ensino de história. A Pesquisa foi desenvolvida junto a um núcleo de jovens e adultos no município de Florianópolis, no ano letivo de 2015, com o objetivo de traçar as possibilidades do ensino de história a partir das narrativas e memórias da/os estudantes. Este trabalho buscou desenvolver uma ação educativa levando em consideração a pesquisa como princípio educativo, modelo de educação que estrutura a educação de jovens e adultos do ensino fundamental no município de Florianópolis. As narrativas das memórias desta/es estudantes foram mobilizadas a partir de entrevistas que foram posteriormente problematizadas individual e coletivamente. O objetivo desta ação foi desenvolver , a partir desta problematização, uma pesquisa junto aos estudantes da EJA. O trabalho de pesquisa junto aos estudantes seguiu o modelo de educação estabelecido pela EJA no município. Durante este processo, as entrevistas da/os estudantes foram transcritas e problematizadas, visando ao final, a criação de uma problemática coletiva que respeitasse os interesses individuais, que foram levantados a partir das narrativas de suas memórias. Após esta ação, uma pesquisa coletiva foi desenvolvida junto aos estudantes, que seguiu a estrutura de etapas desenvolvidas pelo modelo de educação da EJA em Florianópolis e cuscou abrir espaço para as singularidades do ensino de história neste contexto.
Abstract : This dissertation is the result of a research realized at the Programa de Mestrado Profissional em Ensino de História. The research was built with an youth and adult students group from Florianópolis, capital city of Santa Catarina State, during 2015 school year with the purpose of developing possible ways to think the Teaching of History based on student's memories and narratives. This work aimed to develop an educational action considering the research itself as a principle of education, a rule that contributes to the structuring of youth and adult education in Florianopoli's primary education. These students narratives and memories emerged from interviews that were thereafter discussed individually and collectively. The purpose of this educational action was to create a research including the participation of the students. All the method respected the stablished basis in local education for youth and adults. During this process, the student's enterviews were written and then discussed aiming, at the end, to conceive a collective proposition that included individual perspectives and interests. The steps from this work followed the rules from municipal education for youth and adults and intended to open some space to the singularities in the Teaching of History in this context.
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Butvilaitė, Vilma. "SPECIALIŲJŲ UGDYMO(SI) POREIKIŲ VAIKŲ INDIVIDUALAUS LIETUVIŲ KALBOS MOKYMO(SI) VALDYMAS." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2010. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2010~D_20100903_125330-33994.
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Darbo aktualumas. Specialiųjų ugdymo(si)/mokymo(si) poreikių vaikų mokymas yra aktualus, nes pastebima tokių poreikių turinčių vaikų daugėjimo tendencija. Edukaciniais tyrimais siekiama tobulinti specialiųjų poreikių vaikų ugdymą bendrojo lavinimo mokyklose.
Darbo objektas – individualaus specialiųjų ugdymo(si) poreikių vaikų lietuvių kalbos mokymo(si) valdymas.
Darbo tikslas – teoriškai pagrįsti ir empiriškai ištirti specialiųjų ugdymo(si)/mokymo(si) poreikių turinčių vaikų individualaus lietuvių kalbos mokymo(si) valdymą.
Tyrime dalyvavo 60 lietuvių kalbos mokytojų ir 110 mokinių, turinčių specialiųjų ugdymo(si) poreikių. Tyrimas buvo atliekamas Šiaulių ir Raseinių miestų bei minėtų rajonų bendrojo lavinimo mokyklose, nes tų mokyklų administracijos buvo suinteresuotos tyrimo rezultatais.
Tyrimo instrumentai – standartizuota mišraus tipo anketa. Apklausa vykdyta raštu.
Tyrimo metodologija grindžiama humanistine, progresyvistine ugdymo koncepcijomis, integravimo principu.
Tyrimo rezultatai:
Lietuvių kalbos mokytojai, ugdydami specialiųjų ugdymo(si)/mokymo(si) poreikių turinčius vaikus, dažniausiai naudoja tipinius mokymo metodus: aiškinimą, pokalbį, savarankišką darbą, taiko pagalbos mokiniui teikimo būdus.
Mokytojai konstatuoja metodinių kompetencijų trūkumą organizuojant lietuvių kalbos mokymą specialiųjų ugdymo(si)/mokymo(si) poreikių vaikams, tačiau akcentuoja, kad gebėjimų skatinti specialiųjų poreikių vaikų saviugdą, potencinių galimybių plėtrą pakanka.
... [toliau žr. visą tekstą]Relevance of the thesis: teaching children with special needs is urgent because the tendency of increasing numbers of such children is observed. Educational research is aimed at improving training children with special needs. Object of the thesis: managing individual Lithuanian language teaching/learning with special needs children. Aim of the thesis: to prove theoretically and to make an empiric research of managing Lithuanian language teaching/learning with special needs children. Participants of the research: 60 Lithuanian language teachers and 110 pupils with special needs.The research was carried out in Šiauliai and Raseiniai towns and also in secondary schools of the aforementioned districts, because the administrations of those schools were interested in the results of the research. Tools of the research: a standard mixed type questionnaire in a written form. Methodology of the research is based on humanistic, progressive training concepts, also on the principle of intergration. Results of the research: Lithuanian language teachers who teach children with special needs usually apply typical methods of teaching: explanation, conversation, independent tasks, other ways of helping a pupil. Teachers state lack of competence in organising teaching/ learning process with children of special needs. They also stress that they have enough skills to encourage self-help and development of potential possibilities of children with special needs. Children are able to fulfill... [to full text]
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Keshavarzi, Shervin [Verfasser], Holger [Akademischer Betreuer] Reinecke, and Ulrich [Akademischer Betreuer] Mescheder. "Silicon needle-like surfaces for room temperature si-si bonding applications." Freiburg : Universität, 2019. http://d-nb.info/1202010865/34.
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Bai, Gang Nicolet Marc-A. "I. Heteroepitaxy on Si. : II. Ion implantation in Si and heterostructures /." Diss., Pasadena, Calif. : California Institute of Technology, 1991. http://resolver.caltech.edu/CaltechETD:etd-06282007-105319.
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Fasoli, Martina <1996>. "Come si sviluppano e si posizionano i brand emergenti nell'industria dell'automotive." Master's Degree Thesis, Università Ca' Foscari Venezia, 2020. http://hdl.handle.net/10579/17653.
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L’industria automobilistica è considerata una dei settori economicamente più importanti al mondo per volumi di vendita, fatturato ed attori coinvolti.
Negli ultimi anni questa industria ha mostrato un’ottima ripresa dalla crisi del 2008 e si è dimostrata arena di grandi cambiamenti, conseguenza dovuta ad una trasformazione del mercato e delle richieste dei consumatori.
Il cambiamento climatico, l’inquinamento, il costo del petrolio e l’attenzione al pianeta sono diventati fattori dominanti di qualunque settore e questo ha portato le imprese operanti nell’industria dell’automotive a progettare nuove tecnologie e a produrre prodotti eco-friendly: è così che tutti i players del settore e anche i nuovi entranti puntano sull’elettrico, ma non solo.
I brand emergenti stanno dimostrano di avere tutte le conoscenze e le capacità necessarie ad acquisire una quota di mercato e nuovi clienti.
Durante l’elaborato si vuole dimostrare l’importanza dell’innovazione nell’industria delle autovetture e di come i nuovi entranti si posizionano nel mercato.
Verranno analizzati nello specifico 7 brand recentemente fondati; indagando, quindi, le caratteristiche dell’offerta, il vantaggio competitivo e l’impatto sul mercato.
L’automotive si sta trasformando: le auto non saranno più un mezzo di trasporto, ma un insieme di servizi e comfort a quattro ruote.
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Palmino, F. "Etudes d'interfaces terre rare/semi-conducteur et réalisation de croissances nanostructurées: Er/Si, Sm/Si et Pb/Sm-Si." Habilitation à diriger des recherches, Université de Franche-Comté, 2003. http://tel.archives-ouvertes.fr/tel-00091968.
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Brighten, James Cordeaux. "The electrical characterisation of Si and Si/Siâ†1â†-â†XGeâ†X/Si structures grown by molecular beam epitaxy." Thesis, University of Warwick, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387369.
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Bac, Joanna Ewa. "Software intelligence (SI), dependent legal personhood & SI-human amalgamation : an evolutionary step for US patent law and SI." Thesis, University of Aberdeen, 2018. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=237873.
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This doctoral thesis addresses the question of why and how the United States of America (US) legal system should grant legal personhood to software intelligence (SI). This new legal status of SI is visualised as a dependent type of person. The SI dependent legal person would be determined by an inextricable connection between SI and a new type of corporate body, introduced here as SI-Human Amalgamation (SIHA). SI has been defined as one or more computer programmes with an ability to create work that is unforeseen by humans. This includes SI capacity to generate unforeseen innovations, patentable inventions and/or infringe the rights of other patent holders. At present, SI is an entity unrecognised by law. The fact that SI is neither a natural nor a legal person indicates that it cannot be considered the rights' owner or liability bearer. This in turn creates tensions both in society and legal systems because questions, such as, who should hold those rights or be liable for autonomous acts of SI, remain unanswered. It is argued that the SI dependent legal person and SIHA, are necessary to address the new challenges introduced by SI. SI and SIHA, their creativity and actions would be distinct from those performed by human beings involved in the creation of this amalgamation, such as SI's operators or programmers. As such, this structure would constitute an amalgamation based on human beings and SI cooperation (SIHA). SI, as a dependent legal person, would hold the patents rights to its own inventions thus ensuring favourable conditions for the incentives of the US patent system. In addition, the proposed legal framework with the use of legislative instruments could address any liability concerns arising from the foreseen and unforeseen actions, omissions and failure to act of SI.
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Orloski, Renata Villela. "Forças de oscilador ponderadas e tempos de vida para os espectros de Si II, Si VIII e SI IX." [s.n.], 2000. http://repositorio.unicamp.br/jspui/handle/REPOSIP/277318.
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Orientador: Antonio Gomes TrigueirosDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Fisica "Gleb Wataghin"
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Resumo: O objetivo principal deste trabalho é apresentar as forças de oscilador ponderadas ( gf ) e os tempos de vida para todas as transições de dipolo elétrico conhecidas experimentalmente para os íons de Si II, Si VIII e Si IX. A interpretação do cálculo destas duas grandezas é de importância fundamental por exemplo na astrofísica, pois o silício nos seus vários graus de ionização é um dos elementos mais comuns observados em espectros de absorção e emissão de fontes astrofisicas. Neste trabalho é feito para cada um dos íons uma compilação de todos os valores de energia e dos comprimentos de onda de todas as transições conhecidas experimentalmente, mediante estes valores calculamos os tempos de vida e as forças de oscilador ponderadas. Estes cálculos são realizados em uma aproximação relativística multiconfiguracional Hartree-Fock (HFR). Os parâmetros eletrostáticos foram otimizados por um procedimento de mínimos quadrados afim de produzir um melhor ajuste com valores experimentais dos níveis energéticos. Este método produz valores de gf que estão em melhor acordo com as intensidades observadas bem como tempos de vida mais próximos dos experimentais. Neste trabalho são apresentadas todas as linhas espectrais de dipolo elétrico conhecidas experimentalmente para cada um dos íons e que se resumem: -Silício uma vez ionizado, Si II, onde foram observados 146 níveis energéticos e 405 transições de dipolo elétrico na faixa de 700-9500Å; -Silício sete vezes ionizado, Si VIII, onde foram observados 73 níveis energéticos e 96 transições de dipolo elétrico na faixa de 50-1900Å e -Silício oito vezes ionizado, Si IX, onde foram observados 56 níveis energéticos e 103 transições de dipolo elétrico na faixa de 45-450Å
Abstract: The principal objective of this work is to present the weighed oscillator strengths (gf) and the lifetimes for all the eletric dipole transitions experimentally known for the íons of Si II, Si VIII VIII and Si IX. The interpretation of the calculation of these two values is for instance of fundamental importance in the astrophysics, because the silicon in your several ionization degrees is one of the most common elements observed in absorption and emission spectra of astrophysical sources. In this work it is done for each one of the ions a compilation of alI the values of energy and of wavelengths for all the transitions experimentally known, with these values we calculated the lifetimes and the weigthed oscillator strengths. These calculations are accomplished in a multiconfiguration Hartree-Fock relativistic (HFR) approach. The eletrostatic parameters were optimized by a least-square procedure in order to produce a better adjustment with experimental values of energy levels. This method produces values of gf that are in better agreement with the observed intensities as well as lifetimes closer of the experimental ones. In this work we presented all the spectral lines of electric dipole known experimentally for each one of the ions that are summarized: -Silicon one time ionized, Si II, where 146 energy levels and 405 eletric dipole transitions were observed in the range 700-9500Å; -Silicon seven times ionized, Si VIII, where 73 energy levels and 96 eletric dipole transitions were observed in the range 50-1900Å and -Silicon eight times ionized, Si IX, where 56 energy levels and 103 eletric dipole transitions were observed in the range 45-450Å
Mestrado
Física da Matéria Condensada
Mestre em Física
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Oike, Hideaki. "Activation and Reactions of Si-Si and Si-Ge σ-Bonds by Bis(t-alkyl isocyanide)palladium(0) Complexes." Kyoto University, 1996. http://hdl.handle.net/2433/77780.
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Dümmler, Wolfram. "Étude par spectrométrie de masse d'ions secondaires des interfaces Ti/Si₃N₄, Ag/Si₃N₄ et Cu/Si₃N₄." Vandoeuvre-les-Nancy, INPL, 1998. http://www.theses.fr/1998INPL046N.
Full textAbstract:
Les interfaces céramique/métal et leur évolution au cours de traitements thermiques ont été étudiées. Les constituants majeurs des brasures, titane, argent et cuivre, ont été déposés par évaporation et pulvérisation cathodique sur Si₃N₄ poli. Les zones de réactions étant à l'échelle nanométrique, la spectrométrie de masse des ions secondaires (SIMS) est une technique bien adaptée permettant d'obtenir les profils des concentrations des éléments en fonction de la profondeur. Ce travail est centré sur l'étude des possibilités du SIMS utilisant une source de césium pour le bombardement ionique avec détection des molécules MCs+. Nous avons étayé les résultats SIMS par l'emploi de façon complémentaire de SNMS, AES, MEB, DRX et AFM. Contrairement à l'argent et le cuivre, le titane mouille bien la céramique et une couche intermédiaire se forme à l'interface Ti/Si₃N₄. Après des discussions sur les phénomènes qui altèrent la résolution en profondeur d'une analyse SIMS, les calculs de correction sur les coefficients de diffusion D obtenus donnent D ≈ 0,8. . . 2. 10-²⁰ m²/s entre 600°C et 700°C. La pénétration du titane dans la céramique étant très faible, ce sont plutôt des réactions chimiques dans la région interfaciale qui assurent la bonne liaison. Lors des traitements thermiques des échantillons Ag/Ti/ Si₃N₄ et Cu/Ti/ Si₃N₄, on constate un mélange complet des phases avec des réactions complexes dans le cas de Cu/Ti/ Si₃N₄. Pour Ag/Ti/ Si₃N₄, les réactions sont beaucoup moins nombreuses et les phases restent plus pures et bien séparées les unes des autres.
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Kalendra, Vidmantas. "Study of the deep levels induced by the high energy proton and neutron irradiation in the structures of high resistivity Si, SiC and GaN." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2009. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2009~D_20091215_091727-69995.
Full textAbstract:
Investigations made on new materials and their structures for production of particle detectors based on semi-insulating SiC and GaN comprise the technological and applied importance of this study. Innovations in defect control technology, especially, in recognition of extended defects and percolative carrier transport in heavily irradiated detector structures are considered and applied for scientific implementations. These investigations have been performed within a framework of CERN rd50 project. Irradiation by 24 GeV protons varying fluence up to 1016 cm-2 deteriorates rectifying properties of the 4H-SiC particle detectors. Different isotopes produced in 4H-SiC during irradiation by protons have been revealed by gamma spectroscopy. In the non-irradiated GaN material the temperature-dependent variations of leakage current have been unveiled to be caused by the carrier mobility temperature changes. Activation energy values have been extracted for proton radiation induced deep centres in the GaN detectors by thermally stimulated current spectroscopy as well as the isotopes and long-living radio-nuclides have been identified by gamma spectroscopy. In the Si detectors, irradiated by reactor neutrons, the photo-activation energy values have been determined for the deep levels located below the mid-gap by photo-ionisation spectroscopy while isochronal anneals enhance the density of the acceptor-type vacancy-related defects.Disertacijoje išanalizuoti gilieji centrai didžiavaržiuose Si, SiC ir GaN dariniuose, sietini su didelės energijos protonų bei neutronų spinduliuote sudarytais defektais, atskleistos radiacinių defektų transformacijos po iškaitinimų, didelių energijų spinduliuotės įtaka krūvio pernašai ir pagavai medžiagose, tinkamose jonizuojančiosios spinduliuotės detektoriams, tiriamiems pagal Europos branduolinių tyrimų centro (CERN) projektus. 4H-SiC dariniuose, apšvitintuose 24 GeV/c protonais, išanalizuota elektrinių charakteristikų kaita. Iš šiluma skatinamųjų srovių spektrų nustatytos šiluminės aktyvacijos energijų vertės. Taip pat 4H-SiC dariniuose, apšvitintuose protonų įtėkiais, siekiančiais 1016 cm-2, įvertintas skirtingų spinduliuote sukurtų izotopų kiekis. Neapšvitintose GaN dariniuose nustatyta, kad medžiagos elektrinio laidumo parametrų kaitą nulemia krūvininkų judrio kitimas. Apšvitintuose neutronais GaN dariniuose šiluma skatinamųjų srovių spektroskopijos būdu buvo nustatyti dominuojančių defektų lygmenys. Aptikta, kad po apšvitos 24 GeV/c protonų įtėkiais, siekiančiais 1016 cm-2, GaN susidarė 7Be, 22Na ir kiti ilgaamžiai radionuklidai, kurių atominis skaičius A<70, bei žymiai pakito spinduliuotės detektorių krūvio pernašos savybės. Didžiavaržio silicio detektoriuose po apšvitos reaktoriaus neutronais susidarė visa eilė radiacinių defektų, kuriems priskirtinų giliųjų centrų parametrai buvo įvertinti fotojonizacijos spektroskopijos ir tamsinės srovės temperatūrinių kitimų... [toliau žr. visą tekstą]
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Kalendra, Vidmantas. "Didelės energijos protonais ir neutronais sukurtų giliųjų centrų tyrimas didžiavaržio Si, SiC ir GaN dariniuose." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2009. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2009~D_20091215_091739-99248.
Full textAbstract:
Disertacijoje išanalizuoti gilieji centrai didžiavaržiuose Si, SiC ir GaN dariniuose, sietini su didelės energijos protonų bei neutronų spinduliuote sudarytais defektais, atskleistos radiacinių defektų transformacijos po iškaitinimų, didelių energijų spinduliuotės įtaka krūvio pernašai ir pagavai medžiagose, tinkamose jonizuojančiosios spinduliuotės detektoriams, tiriamiems pagal Europos branduolinių tyrimų centro (CERN) projektus. 4H-SiC dariniuose, apšvitintuose 24 GeV/c protonais, išanalizuota elektrinių charakteristikų kaita. Iš šiluma skatinamųjų srovių spektrų nustatytos šiluminės aktyvacijos energijų vertės. Taip pat 4H-SiC dariniuose, apšvitintuose protonų įtėkiais, siekiančiais 1016 cm-2, įvertintas skirtingų spinduliuote sukurtų izotopų kiekis. Neapšvitintose GaN dariniuose nustatyta, kad medžiagos elektrinio laidumo parametrų kaitą nulemia krūvininkų judrio kitimas. Apšvitintuose neutronais GaN dariniuose šiluma skatinamųjų srovių spektroskopijos būdu buvo nustatyti dominuojančių defektų lygmenys. Aptikta, kad po apšvitos 24 GeV/c protonų įtėkiais, siekiančiais 1016 cm-2, GaN susidarė 7Be, 22Na ir kiti ilgaamžiai radionuklidai, kurių atominis skaičius A<70, bei žymiai pakito spinduliuotės detektorių krūvio pernašos savybės. Didžiavaržio silicio detektoriuose po apšvitos reaktoriaus neutronais susidarė visa eilė radiacinių defektų, kuriems priskirtinų giliųjų centrų parametrai buvo įvertinti fotojonizacijos spektroskopijos ir tamsinės srovės temperatūrinių kitimų... [toliau žr. visą tekstą]Investigations made on new materials and their structures for production of particle detectors based on semi-insulating SiC and GaN comprise the technological and applied importance of this study. Innovations in defect control technology, especially, in recognition of extended defects and percolative carrier transport in heavily irradiated detector structures are considered and applied for scientific implementations. These investigations have been performed within a framework of CERN rd50 project. Irradiation by 24 GeV protons varying fluence up to 1016 cm-2 deteriorates rectifying properties of the 4H-SiC particle detectors. Different isotopes produced in 4H-SiC during irradiation by protons have been revealed by gamma spectroscopy. In the non-irradiated GaN material the temperature-dependent variations of leakage current have been unveiled to be caused by the carrier mobility temperature changes. Activation energy values have been extracted for proton radiation induced deep centres in the GaN detectors by thermally stimulated current spectroscopy as well as the isotopes and long-living radio-nuclides have been identified by gamma spectroscopy. In the Si detectors, irradiated by reactor neutrons, the photo-activation energy values have been determined for the deep levels located below the mid-gap by photo-ionisation spectroscopy while isochronal anneals enhance the density of the acceptor-type vacancy-related defects.
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Low, Robert C. D. "Magneto-tunneling of holes in Si/Si1-xGex/Si double barrier structures." Thesis, University of Ottawa (Canada), 1991. http://hdl.handle.net/10393/7712.
Full textAbstract:
Resonant and non-resonant tunneling processes in p-type Si/Si$\sb{\rm 1-x}$Ge$\sb{\rm x}$/Si double barrier structures were investigated at cryogenic temperatures in both planar and perpendicular magnetic fields. A differential conductance measurement technique was devised to observe non-resonant tunneling features superimposed on a rapidly increasing current background. An additional resonant feature was observed at high bias voltage and is attributed to tunneling of holes from the two-dimensional heavy hole subband in the emitter to a third quasi-bound state in the quantum well. Experimental evidence for non-resonant tunneling processes is presented for the first time in p-type double barrier structures. Inter-Landau level transitions between the emitter and the quantum well occur either elastically by scattering from impurities or inelastically with the emission of optical phonons. Both processes have been observed in our samples. Data above 4.2 K suggest that tunneling processes also take place from the three-dimensional valence band edge states in the emitter. A novel spectroscopy of the quasi-bound states in the well was performed by measuring the shift in energy of the resonant tunneling features as a function of applied planar magnetic field.
40
Mülazımoğlu, Mehmet Hașim. "Electrical conductivity studies of cast Al-Si and Al-Si-Mg alloys." Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=75785.
Full textAbstract:
Cast Al-Si and Al-Si-Mg alloys containing up to 12.6 wt. pct. silicon and 1.0 wt. pct. magnesium were prepared. The changes in electrical conductivity/resistivity of these alloys due to strontium additions have been investigated and explained in terms of variations in microstructure. The conductivity behaviour of strontium-containing and strontium-free alloys was found to exhibit marked differences, depending on the silicon and magnesium contents and the rate of solidification. The electrical conductivity of single phase alloys containing less than 1.60 wt. pct. Si decreased with increasing silicon and magnesium levels. However, strontium had no effect on the conductivity of these solid solution alloys since it does not dissolve appreciably in the aluminum matrix or change the solid solubility of silicon and magnesium in aluminum. Silicon precipitation processes in the supersaturated solid solution alloys of Al-Si and Al-Si-Sr have been examined using the Johnson-Mehl-Avrami equation and found to be isokinetic. Strontium, however, retarded the growth rate of silicon precipitates. Strontium did not affect the kinetics of G.P. zone formation in Al-Si-Mg alloys but it suppressed the formation of stable Mg$ sb2$Si precipitates during subsequent aging at 175$ sp circ$C. Unlike the single phase alloys, two phase Al-Si and Al-Si-Sr alloys, in the range of 2.0 to 12.6 wt. pct. Si, exhibited different electrical conductivity behaviour. The strontium-containing alloys showed a higher conductivity than alloys with no strontium, and this conductivity difference increased as the silicon and magnesium contents were increased and the solidification rate was decreased. It has been demonstrated this difference is due to changes in the silicon morphology. Electron scattering at the interface between the aluminum matrix and the eutectic silicon phase contributes significantly more to the resistivity of unmodified alloys than that of modified alloys. In addition, the resistivity of
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Steinhoff, Robert M. (Robert Michael). "Resonant tunneling and its prospects in Si/ZnS and Si/CaF₂ heterostructures." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/43413.
Full textAbstract:
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1997.Includes bibliographical references (p. 50-51).
by Robert M. Steinhoff.
M.Eng.
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Dumont, Lucile. "Rare earth doped si based frequency conversion layer for si solar cell." Caen, 2016. http://www.theses.fr/2016CAEN2035.
Full textAbstract:
Cette thèse porte sur le développement de couches à conversion de fréquence basse à base de silicium permettant une augmentation du rendement des cellules solaires au silicium. Des couches de SiNx dopées avec le couple de terres rares terbium et ytterbium sont élaborées par co-pulvérisation cathodique magnétron radiofréquence. Les propriétés optiques de la matrice hôte non dopée sont étudiées avant le dopage. Elle est ainsi optimisée (via les paramètres de dépôt) dans le but d’obtenir une matrice propice à la conversion en fréquence tout en étant antiréflective. Les systèmes matrice dopée terbium puis matrice dopée terbium et ytterbium sont ensuite optimisés pour obtenir une émission de photoluminescence des ions terbium et ytterbium respectivement la plus intense possible après une excitation dans l’UV. Les mécanismes de transfert de l’énergie entre la matrice et les ions terbium puis entre ces derniers et les ions ytterbium sont détaillés. Le transfert d’énergie coopératif qui a lieu entre les ions terbium et ytterbium lors de la conversion basse (ou down conversion) est très dépendant de la distance entre les ions. Ainsi, un système multicouches alternant les couches dopées avec des ions terbium et des ions ytterbium est développé pour permettre l’excitation d’un plus grand nombre d’ions Yb3+ et donc augmenter l’efficacité du système. L’influence de cette approche sur les propriétés des couches à conversion de fréquence et sur le processus de conversion basse est détaillée. Enfin, une étude sur les couches optimisées déposées sur des cellules solaires Si produites industriellement est menée pour déterminer l’influence de ces couches sur l’efficacité des cellules solairesThis thesis work focuses on the development of silicon based down-conversion layers allowing the improvement of the silicon solar cells efficiency. SiNx terbium and ytterbium co-doped layers are produced by radio-frequency reactive magnetron co-sputtering. The optical properties of the undoped SiNx host matrix are investigated and optimized prior doping to obtain a layer suitable for the down-conversion process and keeping anti-reflective properties. The systems with the terbium-doped matrix and terbium-ytterbium co-doped matrix are optimized with the aim of achieving an intense photoluminescence emission from Tb3+ ions and Yb3+ ions respectively through a wide UV domain excitation. The energy transfer mechanisms between the matrix and the terbium ions and then between those last ions and the ytterbium ones are detailed. The cooperative energy transfer taking place between Tb3+-Yb3+ ions involved in the down-conversion process is highly dependent on the distance between the two ions. Thus, in order to achieve a higher quantum efficiency, a multilayer approach based on alternating stack of Tb- and Yb-doped sublayers has been developed to increase the number of excited Yb3+ ions. The effect of this approach on the frequency conversion process is discussed in details. Lastly, the optimized layers are deposited on industrial silicon solar cells in order to determine the influence of those layers on the solar cells efficiency
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Vlasukova, L. A., V. N. Komarov, V. A. Skuratov, and V. N. Yuvchenko. ""Etchability" of ion tracks in Si02/Si and Si3N4/Si thin layers." Thesis, Sumy State University, 2011. http://essuir.sumdu.edu.ua/handle/123456789/20872.
Full textAbstract:
We have calculated radii and lifetime of the molten regions or the regions heated
to the melting point that are formed under irradiation of amorphous SiO2 and Si3N4 with
swift ions. A computer simulation was carried out on the base of thermal spike model. A
comparison of calculated track parameters with ion track etching data have been made
for these materials.
It is shown that an existence of molten region along swift ion trajectory may be a
criterion for a track “etchability” in the case of SiO2. In the same conditions of chemical
etching diameter of etched tracks in SiO2 is proportional to the radius and lifetime of the
molten region. This information is important for a correct choice of irradiation regime
aimed at preparation of nanoporous layers with high pore density ( 10 10 cm-2).
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/20872
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Xu, Bin. "Si/SiGe thermoelectric generator." Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/25750.
Full textAbstract:
This PhD thesis researches thermoelectric generator (TEG) which transfers wasted heat into electricity by thermoelectric materials. As a parameter used to characterize thermoelectric materials, figure-of-merit (ZT) models of Si bulk, Si/Si_(1-x) Ge_x bulk and Si bulk/nanowires (NWs) are built via building their models of Seebeck coefficient, electrical conductivity and thermal conductivity in this thesis. ZT of Si bulk is increased by 18% by applying a 3μm thick Si_0.8 Ge_0.2 bulk layer, and it is increased by 1000% by applying 35μm long Si NWs. TEG’s output power model which takes account of the effects of thermoelectric material, as well as all parasitic effects that affect TEG’s output power. TEG’s output power model demonstrates the output power depends on thermoelectric material’s characteristics and the contact interface quality between thermoelectric material and metal probe. Thermoelectric material’s characteristics are improved by Si NWs, Si_(1-x) Ge_x bulk, Si_(1-x) Ge_x NWs and spin-on-doping (SOD). SOD also improves the contact interface quality between thermoelectric material and metal probe, which also can be improved by sputter coating a layer of metal on thermoelectric material’s surface. Finally, TEG’s output power is increased by an order of 3 by these techniques.
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Han, Si-ping. "DNA Directed Self-Assembly of Carbon Nanotube Structures." Thesis, 2011. https://thesis.library.caltech.edu/6214/1/Si-ping_Han_PhD_Thesis_version_4_Dec_16_2010.pdf.
Full textAbstract:
Production of pure carbon nanotube species and organization of nanoscale structure are two fundamental barriers to the utilization of CNTs in nanoelectronics. We have developed new methods to characterize double walled carbon nanotube (DWNT) structure by Raman spectroscopy and organize single walled carbon nanotube (SWNT) constructs using DNA.
First, using atomistic force fields calculations, we have shown that the radial breathing modes (RBM) of double walled carbon nanotubes can be accurately modeled as two uniform concentric cylindrical elastic shells coupled by a van der Waals interaction. This model leads to a simple equation which can be solved to give accurate RBMs (given diameters) or diameters (given RBMs).
Secondly, we have developed a method for using DNA origami to template the assembly of complex SWNT structures. In this process, SWNTs are modified with non-covalently attached DNA linkers that present duplex labeling domains for base pairing to complementary single stranded hooks on customized DNA origami. We show that the SWNTs attach at positions and in orientations specified by their labeling sequence, and that nanotube cross-junctions assembled from two different SWNTs in this manner can behave as field effect transistors.
Finally, we have devised a method for using DNA linkers to organize arrays of parallel SWNTs with uniform and selectable inter-nanotube separation of <20 nm. SWNTs are first dispersed in aqueous solution with DNA linkers-spacers that non-covalently anchor onto their sidewalls. When the modified SWNTs are then deposited on mica or polar lipid bilayers and allowed to diffuse on the surface, they form parallel arrays of SWNTs in which different domains of the DNA linker-spacers act to maintain array cohesion and enforce uniform separation. Thus, the use of 7 bp, 20 bp, and 60 bp DNA spacer domains result in ~3 nm, ~8.5 nm, and ~22 nm inter-nanotube separations. We further use the spacer domains as rigid scaffolds for the positioning of Streptavidin proteins between adjacent nanotubes, and give a simple method for transfer of intact arrays onto adhesive glass substrates. Further development of this technology could lead to wafer scale organization of dense parallel SWNT decorated with heterogeneous nanoscale objects.
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Xia, Xiaoxing. "Adaptive and Reconfigurable Architected Materials Driven by Electrochemistry." Thesis, 2019. https://thesis.library.caltech.edu/11595/9/SI%20Video%201.mp4.
Full textAbstract:
Architected materials are a new class of engineered materials with carefully controlled internal structures that give rise to properties that differ from or surpass those of their constituent materials. Recent advances in additive manufacturing provide an extraordinary opportunity to rationally design the structure and the chemical composition of architected materials across multiple length scales to optimize properties and functionalities for a variety of applications. These functional architected materials are capable of decoupling critical trade-offs, such as strength vs. density, to reach new regions of the material property space, and enabling exotic properties that rarely exist in classical materials such as negative refraction and negative thermal expansion.
This thesis probes into the dynamic behaviors of architected materials undergoing electrochemical reactions and aims to provide an in-depth understanding of the underlying mechanisms as well as design principles generalizable for other functional architected material systems. We developed novel fabrication methods based on two-photon lithography and various physical and chemical post-processing techniques to create architected materials with multi-level design freedom including feature sizes, structural geometries, and material compositions, which resonates with the multi-faceted challenges in electrochemical systems. We demonstrated that architected materials provide a new platform to design battery electrodes that could accommodate the large volumetric changes associated with conversion-based electrode materials, while decoupling the longstanding trade-off between active material loading and transport kinetics in batteries. Furthermore, we presented a new class of electrochemically reconfigurable architected materials that could transform their structures in a programmable, reversible and non-volatile fashion, which provide new vistas for designing mechanical metamaterials with tunable phononic bandgaps and deployable micro-devices for biomedical applications.
The multi-scale and multi-physics nature of these electrochemically driven architected materials prompted us to develop a toolset of (1) in situ SEM and optical microscopy to visualize the dynamic responses, (2) coupled chemo-mechanical finite element analysis to reconstruct detailed mechanical evolution as electrochemical reactions proceed, and (3) a statistical mechanics framework to capture the transient interactions between coupled mechanical instabilities. Using these tools, we investigated lithiation-induced cooperative beam buckling in tetragonal Si microlattices: from the deformation mechanisms of individual beams and the cooperative coupling between buckling directions of neighboring beams to the lithiation rate-dependent distribution of ordered buckling domains separated by distorted domain boundaries. Results indicate that local defects and stochastic energy fluctuations play a critical role in the dynamic response of architected materials in a way analogous to that during phase transformations of classical materials. These connections have profound implications on how we could understand and design architected materials by drawing inspiration from established theories in materials science.
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Redknap, David Owen. "Si et même si concessifs." Thesis, 1994. http://hdl.handle.net/2429/5224.
Full textAbstract:
Nous avons étudié les deux structures concessives en français moderne si p, q et même
si p, q. Dans le premier chapitre, nous avons résumé certaines études antérieures sur divers
sujets. La section sur la concession montre qu'il y a sous-entendue a une phrase telle que
même si Jacques est la, je vais partir un rapport du genre si Jacques est Id, je ne vais pas
partir; autrement dit, même si p, q implique si p,~ q (Moeschler & de Spengler, Martin,
Ducrot). Par contre, une phrase telle que s'il est intelligent, il est brouillon se glose mieux
par la paraphrase de Nguyen certes p, mais q: certes il est intelligent, mais il est brouillon.
Dans la section sur la valeur de base des phrases en si p, q (concessives ou non concessives),
on voit que si est le marqueur d'une supposition, et cette supposition sert comme cadre pour
l'énonciation de q qui suit. La section sur même montre que ce mot est le marqueur d'une
échelle argumentative (Ducrot), et qu'il est limite par le contexte et« ce à quoi on
s'attendrait» (Lycan).
Dans le deuxième chapitre, nous avons décrit notre corpus, et nous avons déterminé si
les diverses structures proposées au chapitre précédent étaient présentes dans les exemples du
corpus. La section sur si concessif montre que la paraphrase certes p, mais q peut toujours
paraphraser les phrases concessives de la structure si p, q. Cependant, la structure si p,~ q
est aussi présente, mais indirectement. Finalement, nous avons fait certaines observations sur
le temps des verbes dans les deux propositions/? et q, et nous avons étudié les combinaisons
présent/présent, imparfait/imparfait, passé composé/présent, et plus-que-parfait/imparfait. Les
deux premières combinaisons montrent une opposition—par rapport aux si non concessifs—
au niveau des temps verbaux, les deux dernières au niveau de l'aspect. La section sur les cas
de même si révèle d'une part que toutes les phrases de cette structure possèdent la structure
sous-entendue si p, ~ q, et d'autre part que certains exemples acceptent aussi la paraphrase
de Nguyen. Ceci correspond à la distinction qu'Eriksson fait des phrases en même si portant
sur des faits réels et non réels (virtuels).
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Guihard, Matthieu. "Étude de phase des systèmes Ni/Si-endommagé et Ni/a-Si, par XRD résolue en temps et nanocalorimétrie." Thèse, 2008. http://hdl.handle.net/1866/8045.
Full text
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Chen, Yu-Chang, and 陳昱敞. "The study of magnetic properties in Si/Al,Si/Cu and Si/Ge films." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/15698858591553909427.
Full textAbstract:
碩士國立臺灣海洋大學
材料工程研究所
99
This research is to investigate the composition, surface morphology, chemical bonding and magnetism properties of Si/Al, Si/Cu, Si/Ge thin films prepared by sputtering technique. We introduce different amount of Si while the thickness of the matrix remains constant. At a specific concentration, the highest saturation magnetization was measured. Under the SEM, the surface morphology of the matrix is a thin film with identifiable small particles. It is believed that once the Si or Ge reaches a certain concentration, it will form a network in between these small particles of the matrix. During the experiment, oxygen was accidently introduce into the sputtering process and enhance the magnetic properties. Series of samples deposit under different oxygen ratio were then prepared. It was discovered that the addition of oxygen may result the oxidation not completely of Si and form SiOx, which may be the primary reason for the magnetism measured.
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Tsao, Kai-Yang, and 曹凱揚. "High Strength Si(111) Substrate with Poly-Si/α-Si Sealing Nanotexture for GaN." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/x7thcw.
Full text