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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

[en] SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF GRAPHENE ON GE(100) BY CHEMICAL VAPOUR DEPOSITION / [pt] SÍNTESE E CARACTERIZAÇÃO ESTRUTURAL DO GRAFENO SOBRE GE(100) OBTIDO POR DEPOSIÇÃO QUÍMICA NA FASE VAPOR

CESAR AUGUSTO DIAZ MENDOZA 10 January 2019 (has links)
[pt] A integração do grafeno nos dispositivos nanoeletrônicos depende da disponibilidade de processos de deposição de forma direta sobre o substrato. A deposição direta pode fornecer grafeno uniforme, com alta qualidade e em grande área sobre substratos semicondutores como sílicio ou germânio. Nesta tese, foi sintetizado grafeno diretamente sobre germânio dopado tipo p e com uma orientação cristalina (100) empregando a deposição química na fase vapor. Foi estudada a influência da relação de fluxo entre os gases CH4 e H2 no crescimento de grafeno. As técnicas empregadas para verificar a qualidade das amostras e o tipo de crescimento obtido foram a espectroscopia Raman, microscopia de varredura eletrônica, de tunelamento e de força atômica, e a espectroscopia de tunelamento. Determinamos que para as condições empregadas, o crescimento de grafeno sobre germânio é autolimitado, com a deposição de apenas uma única camada, com poucos defeitos na sua rede cristalina e com o nível de Fermi característico de um material com dopagem tipo n. / [en] The integration of graphene into nanoelectronic devices is dependent on the availability of direct deposition processes, which can provide uniform, large-area and high-quality graphene on semiconductor substrates such as Ge or Si. In this dissertation, we synthesized graphene directly on ptype Ge(100) substrates by chemical vapor deposition. The influence of the CH4:H2 flow ratio on the graphene growth was investigated. Raman Spectroscopy, Raman mapping, Scanning Electron Microscopy, Atomic Force Microscopy and Scanning Tunnelling Microscopy/Scanning Tunnelling Spectroscopy were the techniques employed to verify the quality of the samples and the type of growth. We determined that for the conditions employed, the growth of graphene is self-limited, with only a single layer deposition, with few defects in its crystalline lattice and with Fermi level characteristic of a material with doping type n.
92

Modulace centrální cholinergní neurotransmise. / Modulation of central cholinergic neurotransmission

Valušková, Paulína January 2017 (has links)
Introduction: Central cholinergic system plays a key role in control of different brain functions such as learning, memory, attention, locomotion and rewards. Disrupted integrity, regulation or capacity of cholinergic signalling is closely connected with cognitive symptoms of several neurodegenerative and neuropsychiatric diseases, as Alzheimer disease, Parkinson disease, attention deficit hyperactivity disorder (ADHD), depression, schizophrenia and increased distractibility. The major neurotransmitter of cholinergic neurons is acetylcholine (ACh) and regulation of ACh levels is main pharmacotherapeutic approach to the treatment of diseases associated with central cholinergic system. The aim of the thesis was to study the changes of central cholinergic neurotransmission with respect to various aspects of modulation of ACh levels in the brain by controlling its release through M4 muscarinic receptors (MR), its hydrolysis by acetylcholinesterase (AChE) or butyrylcholinesterase (BChE) and after hydrolysis in the synapse, regulation of the uptake of metabolite choline by high affinity choline transporter (CHT). Methods: Here we used telemetry to measure locomotor activity and body temperature in mice with selective deletion of M4 MR (M4KO) and their wild type (M4WT) controls under the basal conditions...
93

核能廢物公共行政管理方面的「科學-技術-社會(STS)」網絡:台灣與加拿大的必較研究 / Science Technology Society (STS) Networks in the Public Management of Nuclear Waste: a Comparative Study of Taiwan & Canada

阿瑪托, Amato Unknown Date (has links)
On the current state of material distribution of renewable energy plans for development combined with the alternative uses of innovative technologies, there have been multilateral institutional partnerships regulating the actual distribution of nuclear energy programs through the PPPs, which have maintained a primarily scientific role while attracting international attention. In addition, the specific combination of scientific knowledge and technology transfers associated with public-private regulatory spheres has led to a common co-evolution of essential development characteristics, which have been intertwined with public environmental programs and resulting activities referring to the nuclear risk management of nuclear power plants NPPs, and to the formulation of participatory protection mechanisms. In this study, I analyze the comparative institutional status of nuclear energy models in industrial transition stages with waste disposal systems which have been based in Canada and Taiwan. The research focus in this dissertation has been placed over the practical need to identify the adaptive policy approaches in governance leading to local territorial interactions interrelated with a contemporary escalation of environmental technology issues, associated with public-private partnerships (PPPs), especially in terms of operability of STS transfers (science, technology, and societies) developed at societal level. Structurally speaking, the first section of this dissertation discusses introductory explanations already presented in July 2016 for the university commission about the proposed doctoral research design. The second and final parts of this dissertation have been developed at length in view of exploring some of the issues concerning the STS energy transfers and NPPs research policies associated with PPPs configurations. The final discussion section will summarize the literature findings about the changing mechanisms established in energy governance. The evaluative findings have been mostly developed through library archival documents, national reports, and analytical studies which I have compared in this dissertation. Overall for starting point, it can be affirmed that a technocratic vision of dynamic disciplinary elements related to managerial energy configurations of nuclear power plants, including waste disposal programs, has been proposed at regional level through common identification systems, established over public provisions involving regulatory interactions of nuclear sector industries based in East Asia and Canada. International and national attention has been focused on environmental cases of post-disaster emergencies and risk protection factors, particularly following on the Fukushima nuclear plant crisis in Japan in 2011. This structural process has been classified as an international critical domain. Essentially, the constructive experience acquired in governance has relied on cross-countries interpretative democratic models based on the existence of collective information i exchanges, which have actually involved different national regulators, public development actors, and industrial management partners, supported by: scientific experts, regional state officials, non-governmental representatives, and local district communities, among others. Moreover, the resulting collaboration process for public regulatory implementation which has been followed according to governmental aims and rationalization of resources regarding the civilian nuclear energy activities has also acquired a divergent character identified in multi-level state distribution systems. This happens in view of the similar formulation of industrial transition incentives for innovation and technology transfers, also entailing attentive responses formulated by taking into account the material normative reflections; which need to promote a broader view on collective participatory models, also based on public consensus criteria. Consequently, it can be considered that nuclear energy technologies and industrial knowledge transfers have been interlinked to a public set of normative appeals and confidence measures, promoting fundamental support for governance integrative practices. From an industrial point of view, the differentiation of innovation systems pursued through the development of specialized technology districts, for instance, in East Asia and Europe, has been configured according to public-private negotiation patterns assisting on the evolution of STS assessment programs. The corresponding formulation of risk prevention measures and safety assessment principles has been addressed according to the transition obtained with the adoption of alternative renewable energy plans. Managerial innovation capacities have reflected the temporal adaptation to development changes, which have been related to the emergence of nuclear fuel-cycle radioactive programs, and nuclear waste disposal activities. At implementation level, the direct involvement of community actors and environmental institutions has come into play leading to the identification of multilevel governance routes, by enhancing the knowledge transfers and learning systems, compatible with national and local collectivities, as well as, territorial and internal capacities. At the same time, the spatial regulatory requirements for regional identifications of the technologies used and the PPP agreements prepared in connection with nuclear energy facilities, and civilian energy installations, have testified the need to introduce learning cooperation stages for the evaluative and monitoring processes. These changing adaptation stages have been publicly controversial. At the end of bitter regional local disputes, the investigative agencies producing case-based reports have indicated the status of public concern and risk perceptions on nuclear safety issues, particularly for the local population living in proximity to NPPs, reflecting on common detrimental effects in terms of public governance and mutual trust conditions. The complex variation of public understanding about the programmatic issues surrounding nuclear science development and the environmental impacts has drawn us to an analytic core of ii structural determinants, which have been investigated in order to compare the international cooperation principles and the practical nationally-based conducts. For the identification of risk protection assessments of national capacities, I have elaborated this study project for comparative purposes, by trying to emphasize the critical aspects of public STS maintenance systems, which will require a legal status and clarification for the future generations in order to guarantee security and safety for everyone.
94

Formuler les valeurs du nucléaire : Communautés, équations, budgets et débats autour des déchets nucléaires / Formulating Nuclear Values : Communities, Equations, Budgets and Debates with Nuclear Waste

Saraç-Lesavre, Başak 09 December 2015 (has links)
La thèse traite de la valorisation comme un processus à la fois continu, constructif et contesté. Elle aborde cette question théorique au travers de l'étude d'un objet de valorisation complexe : le traitement des déchets nucléaires aux États-Unis. Objet ontologiquement ambivalent, les déchets nucléaires peuvent être valorisés ou dévalorisés selon des perspectives très variées, qui offrent à la sociologie de l'évaluation un banc d'essai pertinent. La thèse s'appuie sur l'étude d'une série de situations où la formulation des valeurs du nucléaire pose problème. Ce sont, notamment, l'ordonnancement et les vicissitudes du processus budgétaire mis en œuvre pour financer le programme de gestion des déchets nucléaires Nord-américain, les plans conçus pour répartir la responsabilité financière dans le traitement d'un matériau qui selon toutes prévisions restera dangereux pendant un million d'années, les efforts d'un groupe d'acteurs pour attacher l'avenir de leur communauté à celui des déchets nucléaires, ou les utilisations d'une convention pour estimer la valeur économique du combustible usé. La thèse montre que les processus de valorisation et dévalorisation sont loin de se limiter à l'objet soumis à évaluation ; ces processus rendent d'autres valeurs explicites, les valeurs "de l'État", d'une communauté politique, d'une convention économique. La thèse propose d'utiliser la notion de « révaluation », d'une part, parce qu'elle permet d'expliciter l'imbrication des relations entre les processus d'évaluation et de valorisation et, d'autre part, parce qu'elle permet de souligner la particularité de la période sur laquelle porte la recherche, à savoir une période où la relance de l'énergie nucléaire a été publiquement débattue et où le gouvernement américain cherchait à reformuler sa politique de gestion des déchets nucléaires. / This thesis approaches valuation as an on-going, constructive and contested process. She addresses this theoretical issue through the study of a very complex object of valuation: nuclear waste in the context of the United States. As an ontologically ambivalent object, nuclear waste can be valued or devalued from many angles, which provides an intriguing and exciting test bed to unfold a sociology of valuation. The thesis examines a multitude of sites where the question of the formulation of nuclear values is being raised. These sites are, for example, the design and vicissitudes of the budgetary process conceived to finance the North American nuclear waste program, the trials set up in order to distribute the financial responsibility of a material expected to remain hazardous during the next million years, the efforts of a group of actors to attach the future of their community to the future of nuclear waste, or the uses of an economic convention to estimate the economic value of spent nuclear fuel. This thesis shows that processes of valuation are never limited to the object that is subjected to valuation and proposes the notion of revaluation, first, to articulate the intertwined relationship between the processes of evaluation and valuation, and second, to signify the particularity of the period during which the research has been undertaken, namely a moment when the revival of nuclear energy was publicly debated, and a moment when the U.S. government was seeking to reformulate its nuclear waste policy.
95

British electricity policy in flux : paradigm ambivalence and technological tension

Emamian, Seyed Mohamad Sadegh January 2014 (has links)
Drastic changes have taken place in UK electricity policy over recent years as government has sought to address the challenges associated with energy security, affordability and commitments to reduce carbon emissions. This study investigates the underlying policy changes between the year 2000 and 2012, particularly the Electricity Market Reform, as the most fundamental transformation in the British power market since liberalisation, almost three decades ago. It illustrates that although this policy had revised the long legacy of market-based and technology neutral electricity policymaking, it was yet to be claimed as a wholesale paradigmatic shift, because, as of 2012, it still suffered from a form of paradigm ambivalence and socio-technical lock-in. Furthermore, this research identifies an accumulative process of policy change explaining how a complex set of dynamics transformed the UK electricity policy mix. The thesis relies empirically on conducting 53 semi-structured interviews as well as scrutinising policy documents and relevant secondary studies. The thesis draws relevant approaches within policy studies that attend to address continuity and change in policy frameworks, in particular the Advocacy Coalition Framework (Sabatier 1999) and Policy Paradigm (Hall 1993) perspectives. The study contributes to this literature in three distinctive ways. First, it questions the adequacy of existing frameworks for conceptualising policy change in ‘large-technical’ and ‘techno-centric’ subsystems, such as electricity policy. In return, it introduces technology preference, as a policy component capturing the socio-technical elements of electricity policymaking. Second, to explain why and how such significant changes had been undergone, it forms a bridge between the characteristics of policy change and the extent that existing policies are perceived as irreconcilable policy failures. By this, it, albeit, moves beyond the conventional typology of change drivers in policy literature. Third, this research extends the emerging concept of negotiated agreement and policy compromise as a pathway to evolutionary changes (Sabatier & Weible 2007). Inspired by Institutional Change theory (Mahoney & Thelen 2010), it proposes that compromised policies are often at the risk of policy reversibility and retrenchment, subject to any shift in the contextual conditions they have originated in. Overall, the thesis provides an understanding of one of the very complex and contemporary cases for studying policy change theories.
96

Kunskapsprocesser :  Skapande av ny kunskap och kunskapsöverföring i ett komplext projekt

Nylen, Marcus, Persson, Staffan January 2008 (has links)
<p>Tjänsteföretag är kunskapsintensiva företag som är beroende av den kunskap som finns inom företaget. Det är vanligt inom dessa företag att basera arbetet på en projektform. Detta innebär att när ett projekt ska bedrivas tillsätts en projektgrupp, bestående av individer som besitter den kunskap som behövs för att slutföra projektet. Projektets karaktär kan vara av varierande slag men i de flesta fall kommer ett skapande av ny kunskap att äga rum samt även någon form av kunskapsöverföring. För att projektets resultat ska bli en allmänt vedertagen modell eller produkt så måste den framtagna kunskapen valideras av beställaren. Därefter är det upp till organisationen att förvalta den framtagna kunskapen. För att kunna identifiera dessa kunskapsprocesser har vi i denna kandidatuppsats undersökt ett specifikt projekt, Alphaprojektet, som har bedrivits inom företaget Gamma AB. Gamma AB är ett tjänsteföretag som är verksamt inom tre affärsområden. Målet med Alphaprojektet var att kunna erbjuda marknaden ett koncept tidigt i kundens arbetsprocess vilket binder samman dessa tre affärsområden. Den process och det problem som denna uppsats beskriver är hur kunskap skapades inom denna projektgrupp samt hur den skapade kunskapen förvaltades av projektets beställare. En av de slutsatser som denna uppsats genererat är att kunskap skapades i Alphaprojektet ge-nom att individer med skilda bakgrunder och olika mentala modeller interagerade. Denna skapade kunskap tog, mer konkret formen av att projektgruppen enades kring att de måste skapa ett gemensamt mål. Detta mål var att de skulle inrikta sig mot ett visst antal kunder och att dessa kunder sedan skulle kunna utnyttjas som referenser för framtida uppdrag samt att Tidiga skeden är komplext och svårt att definiera. Beställaren valde under Alphaprojektets gång att omstrukturera projektet. De bakomliggande orsakerna till detta var enligt beställaren själv att projektet skulle ha tagit för lång tid och på så sätt medfört ökade kostnader och även problem inom den egna organisationen. Enligt vår me-ning berodde omstruktureringen på fler orsaker. Vår slutsats är att organisationen misslycka-des att förvalta den kunskap som gruppen skapade samt att projektets mål, initialt, inte var tillräckligt tydligt definierade.</p>
97

Prisjämförelsesajters betydelse för e-handlare och deras konsumenter : En studie av prisjämförelsesajters roll i samspelet mellan Internerbaserade återförsäljare av hemelektronik och deras konsumenter

Isaksson, Fredrik, Stridh, Ola January 2008 (has links)
<p>Det finns idag ett väldigt stort urval av återförsäljare som agerar på Internet och dessa kan vid en första anblick te sig väldigt svåra att överskåda för konsumenter inför ett köp. Prisjämförelsesajter finns därför som en konsumentguide som med sina sökfunktioner snabbt hjälper konsumenter att hitta återförsäljare med de billigaste priserna samt även tillhandahåller information om såväl produkter som återförsäljare. Uppsatsen syftar till att studera prisjämförelsesajternas roll i samspelet mellan återförsäljare och konsument på den Internetbaserade marknaden för hemelektronik. Den kvalitativa studien grundas på intervjuer med de två marknadsledande prisjämförelsesajterna, PriceRunner och Prisjakt, samt intervjuer med tre återförsäljare inom detta branschsegment, CDON, Expert och Kameraexperten. Intervjuerna analyseras med hjälp utav en analysmodell där vi kopplat samman flera olika marknadsföringsteorier. Det resultat vi kommit fram till visar på att det nätverk av återförsäljare och konsumenter som prisjämförelsesajterna tillhandahåller har lett till en ökad konsumentmakt men att detta inte behöver ses som negativt för återförsäljarna då dessa har stora konkurrensfördelar att vinna om de sköter sina kundrelationer på ett bra sätt.</p>
98

Konceptbyte på Värmlands nation : Projekthantering och organisationsstruktur vid en studentnation i Uppsala

Karlsson, Jon January 2008 (has links)
<p>Studentorganisationen Värmlands nation i Uppsala genomdrev under våren och sommaren 2006 ett konceptbyte på sin dansklubb. Initiativet togs av nationsledningen, men genomförandet skedde i form av ett självständigt projekt drivet av projektanställda nationsmedlemmar. Den här uppsatsen studerar hur nationens ideella organisationsstruktur har påverkat projektarbetet. Detta görs främst genom intervjuer med berörda individer inom både nationen och projektet. Uppsatsen utgår från organisationsteori av Henry Mintzberg och projektteori av Anders Marttala, Kjell Nordberg och Anders Blomé.</p><p>Värmlands nations organisationsform kännetecknas av ideella drivkrafter, informell kommunikation och att många olika individers diversifierade insatser resulterar i en mångfasetterad och stundtals svåröverblickbar helhet. Denna struktur har sina fördelar i en bred studentorganisation med väldefinierade och återkommande aktiviteter, men när den överfördes till ett tillfälligt projekt visade den sig skapa en hel del problem i form av oklara riktlinjer och svårdefinierade ansvarsfördelningar. Trots detta är det tydligt att arbetssättet inte varit enbart en nackdel; projektets lyckade resultat kan till viss del härledas de nationsaktivas självpåtagna insatser. Sammantaget kan dock ett behov av tydligare arbetsfördelning och klarare arbetsledning identifieras i uppsatsen.</p>
99

Desired Features and Design Methodologies of Secure Authenticated Key Exchange Protocols in the Public-Key Infrastructure Setting

Wang, Hao-Hsien January 2004 (has links)
The importance of an authenticated key exchange (AKE) protocol has long been known in the field of cryptography. Two of the questions still being asked today are (1) what properties or features does a secure AKE protocol possess, and (2) How does one, in a step by step fashion, create a secure AKE protocol? This thesis aims to answer these two questions. The thesis contains two parts: one is a survey of previous works on the desired features of the Station-to-Station (STS) protocol, and the other is a study of a previously proposed design methodology in designing secure AKE protocols, as well as contributing an original idea of such methodologies. Descriptions and comparisons of the two design methodologies are included. The thesis surveys the literature and conducts a case study of the STS protocol, analyzes various attacks on STS through some known attacks to it, and extracts the desired properties and features of a secure AKE protocol via the case study. This part of the thesis does not propose any new result, but summarizes a complete list of issues one should take consideration of while designing an AKE protocol. We also show that at the end of this part, a secure version of STS which possesses the desired features of an AKE protocol. The other major part of the thesis surveys one design methodology of creating a secure AKE protocol by Bellare, Canetti, and Krawczyk; it is based on having a secure key exchange protocol then adding (mutual) authentication to it. The thesis then proposes another original design methodology; it starts with a secure mutual authentication protocol, then adds the secure key exchange feature without modifying overheads and number of flows of the original mutual authentication protocol. We show in this part the "secure" AKE protocol developed through these two design approaches is identical to the secure version of STS described in the other part, and thus possesses the desired features of a secure AKE protocol. We also give a proof of security of the secure AKE protocol developed under our design methodology.
100

Nuclear Risk and Rationality: Reevaluating Rational Decision Making through the Lens of Tohoku’s Nuclear Evacuees

James, Kayon K 01 January 2017 (has links)
The purpose of this paper is the examination of previous STS-based frameworks for rational risk evaluation and the role of Fukushima residents as co-creators of new technical codes in safety and risk. To accomplish this task, the causes of nuclear refugees’ uncertainty and distrust towards the industry and the applicability of frameworks for scientific proceduralism and democratic rationalization by Kristin Shrader-Frechette and Andrew Feenberg to this issue will be discussed.

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