Global ETD Search

261	A Quantum Chemical Investigation of Chemical Vapour Deposition of Fe using Ferrocene and Plasma Electrons Andersson, Felicia January 2023 (has links) Thin films provide a remarkable asset, as depositing a thin surface layer can completely alter a material’s characteristics and provide new, inexpensive, and valuable properties. In 2020, a new Chemical Vapour Deposition (CVD) approach was developed at Linköping University, using plasma electrons as reducing agents for the deposition of metallic thin films. To understand the CVD approach, comprehension of the deposition chemistry is crucial. In this thesis, I have performed a theoretical examination of the gas phase and surface chemistry of ferrocene in the recently developed CVD method to form metallic iron thin films, using plasma electrons as reducing agents. Results show that ferrocene anion formation and dissociation are probable in the gas phase, depending on the energy of the plasma electrons. It gets successively easier to dissociate the complex after gaining electrons. The most probable gas phase species leading to film formation was determined as FeCp2-, FeCp, and Cp− under the normal deposition parameters. An electron energy above 220 kJ/mol would suffice for ion formation and dissociation to form FeCp and Cp− fragments. On the surface, ferrocene’s vertical and horizontal adsorption is equally probable, with energies around -72 kJ/mol. Cp, Fe, and FeCp with Fe facing towards the surface interacts stronger with the surface than ferrocene, with adsorption energies of -179, -279 kJ/mol, and -284 kJ/mol. FeCp with Fe facing up from the surface had adsorption energy of -23 kJ/mol. As the surface bonding of Fe and FeCp with Fe facing the surface is stronger than for the other species, this poses a possible way of tuning the CVD method to limit carbon impurities. By providing above 180 kJ/mol energy, for example in the form of heating the substrate, the unwanted species FeCp2, Cp, and FeCp with the ring facing downwards would desorb from the surface, leaving the Fe and FeCp fragments with iron facing towards the surface still adsorbed. This poses a possible way of reducing carbon impurities. Quantum chemistry Ferrocene Silver Ag(111) Plasma electrons Surface chemistry Electronic structure DFT Kvantkemi Ferrocen Silver Ag(111) Plasmaelektroner Ytkemi Elektronstruktur DFT Chemical Sciences Kemi Theoretical Chemistry Teoretisk kemi Physical Chemistry Fysikalisk kemi Materials Chemistry Materialkemi
262	Numerical Estimation of Critical Exponents in the 3D XY Model / Numerisk uppskattning av kritiska exponenter i 3D XY-modelen Beiming, Christoffer January 2023 (has links) The experimentally obtained value of the critical exponent ν is presently in significant disagreement with current theoretical predictions for the λ-universality class. We suggest two novel approaches of determining the exponents ν and η by utilizing the effects of finite size scaling. The numerical computations are performed using Monte Carlo simulations of a 3D XY model, realized on a bc-lattice. Different sizes of systems are then either compared in pairs (pairwise fit) or all together (joint fit), in order to fit the correct value of the critical exponents to our sampled data. We find for the pairwise fitting procedure that ν = 0.6731(36) and η = 0.0351(39). Likewise, the joint fitting procedure yields ν = 0.6727(58) and η = 0.0349(49). The predictions for ν are very consistent with existing works, while the values for η are somewhat lower than expected from existing literature results. / Det experimentella värdet av den kritiska exponenten, ν, skiljer sig för närvarande från de teoretiska uppskattningarna som gjorts för λ-universalitetsklassen. Vi föreslår två nya metoder för att bestämma exponenterna ν och η, genom att använda effekterna från ändlig storleksskalning. De numeriska beräkningarna utförs med hjälp av Monte Carlo simulering av en tredimensionell XY-modell, realiserad på ett kubiskt gitter. Olika sys- temstorlekar jämförs sedan antingen parvis eller gemensamt, för att kunna anpassa värdet på de kritiska exponenterna till data. Vi erhåller ν = 0.6731(36) och η = 0.0351(39), för parvis anpassning, samt ν = 0.6727(58) and η = 0.0349(49) för gemensam anpassning. Det beräknade värdet på ν stämmer bra överens med andra arbeten, medan värdena på η är något lägre än förväntat från tidigare uppskattningar. Theoretical physics Condensed matter theory Phase transitions XY model Critical exponents Computational physics Monte Carlo simulations Teoretisk fysik Kondenserade materiens teori Fasövergångar XY-modellen Kritiska exponenter Beräkningsfysik Monte Carlo simulering Physical Sciences Fysik
263	Effects of power-law correlated disorder on a 3D XY model / Effekterna av potenslagskorrelerad oordning på 3D XY-modeller Broms, Philip January 2022 (has links) This thesis investigates the effects of power-law correlated disorder on a three-dimensional XY model and the Weinrib-Halperin disorder relevance criterion’s pre-dictive ability. Ising models are used as a map to realise disorder couplings. Simula-tions are conducted using hybrid Monte Carlo method constituting Metropolis’ andWolff’s algorithms. Two cases using two-dimensional and three-dimensional Isinggenerated disorder corresponding to (d + 1)- and d-dimensional models are tested.In addition, a superficial scaling analysis is performed to highlight the change ofuniversality class.It is shown that magnetisation, response functions and Binder ratio along withits temperature derivative display stark differences from the pure XY model case.The results agree with the Weinrib-Halperin criterion in terms of predicting achange of universality class but show a discrepancy in both qualitative and nu-merical results. The main new result is that power-law correlated disorder canintroduce two phase transitions at different critical couplings. This is in disagree-ment with prior established theory and predicts new physics to be investigated insuperconductors and superfluids with correlated disorder. / Det här examensarbetet undersöker hur potenslagskorrelerad oordning påverkar en tredimensionell XY-modell samt förutsägelseförmågan hos Weinrib-Halperins oordningskriterium. Oordningen realiseras genom varierande kopplingsstyrka som definieras med hjälp av Isingmodeller. Simuleringar utförs med hjälp av en Monte Carlo-hybridmetod bestående av Metropolis och Wolffs algoritmer. Undersökningen innefattar oordning genererad av tvådimensionella samt tredimensionella Isingmodeller med syftet att emulera oordning hos (d + 1)- och d-dimensionella modeller. Dessutom utförs en ytlig skalningsanalys för att tydliggöra förändringen hos universalitetsklassen. Resultaten uppvisar markanta skillnader från en ren XY-modell i magnetiseringen, responsfunktionerna och Binderparametern med temperaturderivata. Resultaten bekräftar Weinrib-Halperin-oordningskriteriets förmåga att förutsäga förändring hos universalitetsklassen men avviker från exakta kvalitativa och kvantitativa prognoser. Det huvudsakliga nya resultatet är att potenslagskorrelerad oordning kan introducera två fasövergångar vid två olika kritiska kopplingar. Detta motsäger den etablerade teorin och pekar på ny fysik att utreda hos supraledare och suprafluider med korrelerad oordning. Condensed matter physics Ising model XY model Markov Chain Monte Carlo Phase transition Disorder Theoretical physics Wolff algorithm Kondenserade materians teori Isingmodell XY-modell Markovkedje-Monte Carlo-metoder Teoretisk fysik Oordning Fasövergångar Wolffalgoritmen Physical Sciences Fysik
264	Fri vilja och Principen om alternativa möjligheter : Om Frankfurt-exempel och motargumentet ”glimt av frihet” / Free will and the Principle of alternate possibilities : About Frankfurt-style examples and the counterargument "flicker of freedom" Blomsterberg, Erik January 2024 (has links) No description available. philosophy theoretical philosophy Frankfurt-style examples PAP Principle of alternate possibilities flicker of freedom filosofi teoretisk filosofi Frankfurt Stump Naylor Frankfurt-exempel Principen om alternativa möjligheter glimt av frihet Philosophy Filosofi
265	Pedagogers uppfattning om barns samtal på fritidshem : En fenomenologisk studie Callert, Robin, Husén, Kevin January 2017 (has links) Detta är en studie som utforskar fritidspedagogers uppfattning om samtal med barn i deras verksamhet. Vår utgångspunkt var sokratiska och filosofiska samtal som vi stötte på under en kurs i ”barns existentiella frågor”. Vi blev då nyfikna över hur detta såg ut i verkligheten, om det fanns överhuvudtaget. Vi använder oss av ett fenomenologiskt perspektiv kombinerat med kunskapsbegrepp från Aristoteles för att få goda verktyg i en analys utifrån kvalitativa intervjuer. Vi använder även Skolinspektionens kvalitetsgranskning av fritidshemmen från 2010 för att få ett bollplank att jämföra de mönster vi hittat och de mönster de identifierat. I arbetet kom vi fram till att pedagoger ofta strävar efter mål som de inte alltid kan uppnå av olika orsaker samt att de i samtal med elever vill ha det resultat som ett Sokratiskt eller filosofiska samtal har möjlighet att bidra till. Dock upptäckte vi att man genom samtal försöker lära elever praktisk klokhet men med samma metoder man använder för att lära ut teoretisk kunskap. / In this study, we will be exploring the extended school teacher’s perception of dialogue with children in their work environment. The starting point for this study happened when we encountered Philosophical and Socratic dialogues as a didactic tool in our course “the child's existential questions”. This sparked our interest, trying to figure out how these would look like in the real world, if they were present at all. This study is using a phenomenological perspective, combined with Aristotle's theory of knowledge with the purpose of giving us the tools required for analyzing our qualitative interviews. We will also be using a report from Skolinspektionen regarding the quality of extended school teacher’s work environment from 2010 with the purpose of comparing the results we find in our study against the results they identified. The results of this study concluded that pedagogues often strive for goals that may be difficult to reach, for a couple of different reasons. Also in their dialogues with children they strive for results that philosophical and Socratic dialogues can contribute to. We also learned that the extended school teachers try to teach practical wisdom but with the tools of teaching theoretical knowledge. Extended school education extended school pedagogics dialogue socratic dialogue philosophical dialogue qualitative interview phenomenology lifeworld phronesis episteme theoretical knowledge practical knowledge measurable knowledge unmeasurable knowledge Fritidshem fritidspedagogik samtal sokratiska samtal filosofiska samtal kvalitativ intervju fenomenologi livsvärld fronesis episteme teoretisk kunskap praktisk kunskap mätbar kunskap omätbar kunskap Educational Sciences Utbildningsvetenskap
266	Iterabilitet, upprepning och permanens : En kritisk analys av debatten mellan Derrida och Searle / Iterability, repetition and permanence : A critical analysis of the debate between Derrida and Searle Gardfors, Johan January 2009 (has links) <p>The essay seeks to clarify some of the decisive but often obscured issues in the famous debate between Jacques Derrida and Jonn F. Searle. The debate commenced in 1977 with the publication in <em>Glyph</em> of Derrida’s lecture <em>Signature Event Context</em> from -71, followed by Searle’s <em>Reiterating the Differences</em>. A Reply to Derrida and subsequently Derrida’s reply <em>Limited Inc a b c …</em> which encouraged Searle to renew his criticism. I situate the debate within a philosophical context where questions of the aim of philosophy and the nature of philosophical writing cannot be excluded from the specific topics that are being discussed. Starting from Derrida’s controversial reading of Austin, where a few key points of criticism are placed under scrutiny, I proceed to problems of writing and communication where special attention is paid to the concept of iterability and Searle’s remark that this has been confounded with permanence in Derrida’s exposition. The concept of ”writing” is examined as a crux in the understanding of the two philosophers. And iterability is then found to be derieved from the theorization of absence in relation to that very concept. Iterability designates an essential possibility of absence and implies the possibility of every mark to be grafted onto new contexts of significance. Thus it draws the consequences of a general repeatability, within which difference is underscored as the inevitable outcome. The last section of the essay relates to the phenomenological project of investigating the genesis of idealization and traces the emergence of iterability in Derrida’s further writings on Husserl, where repetition can be perceived of as constitutive for ideality and thus for identity. Bearing on this observation, the type/token-distinction, proposed by Searle to undo the problem of iterability, is subjected to further inquiry and linked to the process of idealization, within which iterability is revealed to have a temporal relevance that also affects the notion of permanence. The claim is then made that iterability should be understood as a fundamentally ambiguous phenomenon through its dual relation to identity and difference. Its utility is found to be hinged upon the status of the possible. Finally, the question of iterability as concept is posed, which entails its interdependence upon notions of dissemination and différance.</p> iterability repetition permanence Derrida Searle Austin Husserl quotation citation citationality repeatability grapheme absence writing iterabilité Derrida Searle Austin Husserl écriture abscence graphème graphematicité identité différance iterabilitet upprepning permanens Derrida Searle Austin Husserl upprepbarhet grafem grafematicitet identitet idealitet frånvaro idealisering beständighet skrift talaktsteori talakter dissemination citat citationalitet repetition Philosophy subjects Filosofiämnen Theoretical philosophy Teoretisk filosofi
267	Topics on D-branes and Holography Smedbäck, Mikael January 2004 (has links) <p>We discuss various aspects of D-branes in string theory and holography in string theory and loop quantum gravity. </p><p>One way to study D-branes is from a microscopic perspective, using conformal field theory techniques. For example, we investigate the question of how D-branes can be introduced into orbifolded theories. Another way to study D-branes is from a space-time perspective. An example is provided by unstable D-branes, where we compute an effective action describing the decay of a bosonic D-brane. </p><p>The holographic principle is a proposed duality which suggests that a theory in any region has a dual description on the boundary. We explore two examples: (1) The area law for the entropy of a black hole in the framework of loop quantum gravity, related to particular regularizations of the area operator. (2) The AdS/CFT correspondence proposal, where we investigate a string pulsating on AdS using spin chains.</p> Theoretical physics theoretical physics string theory D-branes dualities AdS/CFT spin chains Bethe ansatz boundary conformal field theory conformal bootstrap tachyon condensation string field theory loop quantum gravity black holes area spectrum Hawking radiation holographic principle Teoretisk fysik Physics Fysik
268	The code of Concord : Emerson's search for universal laws Hallengren, Anders January 1994 (has links) The purpose of this work is to detect a pattern: the concordance of Ethics and Aesthetics, Poetics and Politics in the most influential American thinker of the nineteenth century. It is an attempt to trace a basic concept of the Emersonian transcendentalist doctrine, its development, its philosophical meaning and practical implications. Emerson’s thought is analyzed genetically in search of the generating paradigm, or the set of axioms from which his aesthetic ideas as well as his political reasoning are derived. Such a basic structure, or point of convergence, is sought in the emergence of Emerson’s idea of universal laws that repeat themselves on all levels of reality. A general introduction is given in Part One, where the crisis in Emerson’s life is seen as representing and foreshadowing the deeper existential crisis of modern man. In Part 2 we follow the increasingly skeptical theologian’s turn to science, where he tries to secure a safe secular foundation for ethical good and right and to solve the problem of evil. Part 3 shows how Emerson’s conception of the laws of nature and ethics is applied in his political philosophy. In Part 4, Emerson’s ideas of the arts are seen as corresponding to his views of nature, morality, and individuality. Finally, in Part 5, the ancient and classical nature of Concord philosophy is brought into focus. The book concludes with a short summary. Ralph Waldo Emerson (1803-1882) natural law ethics aesthetics esthetics politics USA ethics and physics laws of nature laws of society laws of art American literature American philosophy American history legal philosophy constitutional law human rights rule of law Literature Litteraturvetenskap Theoretical philosophy Teoretisk filosofi Practical philosophy Praktisk filosofi Public law Offentlig rätt Other law Övrig rätt Theory of science Vetenskapsteori History of science and ideas Idé- o lärdomshistoria Political science Statsvetenskap
269	Iterabilitet, upprepning och permanens : En kritisk analys av debatten mellan Derrida och Searle / Iterability, repetition and permanence : A critical analysis of the debate between Derrida and Searle Gardfors, Johan January 2009 (has links) The essay seeks to clarify some of the decisive but often obscured issues in the famous debate between Jacques Derrida and Jonn F. Searle. The debate commenced in 1977 with the publication in Glyph of Derrida’s lecture Signature Event Context from -71, followed by Searle’s Reiterating the Differences. A Reply to Derrida and subsequently Derrida’s reply Limited Inc a b c … which encouraged Searle to renew his criticism. I situate the debate within a philosophical context where questions of the aim of philosophy and the nature of philosophical writing cannot be excluded from the specific topics that are being discussed. Starting from Derrida’s controversial reading of Austin, where a few key points of criticism are placed under scrutiny, I proceed to problems of writing and communication where special attention is paid to the concept of iterability and Searle’s remark that this has been confounded with permanence in Derrida’s exposition. The concept of ”writing” is examined as a crux in the understanding of the two philosophers. And iterability is then found to be derieved from the theorization of absence in relation to that very concept. Iterability designates an essential possibility of absence and implies the possibility of every mark to be grafted onto new contexts of significance. Thus it draws the consequences of a general repeatability, within which difference is underscored as the inevitable outcome. The last section of the essay relates to the phenomenological project of investigating the genesis of idealization and traces the emergence of iterability in Derrida’s further writings on Husserl, where repetition can be perceived of as constitutive for ideality and thus for identity. Bearing on this observation, the type/token-distinction, proposed by Searle to undo the problem of iterability, is subjected to further inquiry and linked to the process of idealization, within which iterability is revealed to have a temporal relevance that also affects the notion of permanence. The claim is then made that iterability should be understood as a fundamentally ambiguous phenomenon through its dual relation to identity and difference. Its utility is found to be hinged upon the status of the possible. Finally, the question of iterability as concept is posed, which entails its interdependence upon notions of dissemination and différance. iterability repetition permanence Derrida Searle Austin Husserl quotation citation citationality repeatability grapheme absence writing iterabilité Derrida Searle Austin Husserl écriture abscence graphème graphematicité identité différance iterabilitet upprepning permanens Derrida Searle Austin Husserl upprepbarhet grafem grafematicitet identitet idealitet frånvaro idealisering beständighet skrift talaktsteori talakter dissemination citat citationalitet repetition Philosophy subjects Filosofiämnen Theoretical philosophy Teoretisk filosofi
270	Topics on D-branes and Holography Smedbäck, Mikael January 2004 (has links) We discuss various aspects of D-branes in string theory and holography in string theory and loop quantum gravity. One way to study D-branes is from a microscopic perspective, using conformal field theory techniques. For example, we investigate the question of how D-branes can be introduced into orbifolded theories. Another way to study D-branes is from a space-time perspective. An example is provided by unstable D-branes, where we compute an effective action describing the decay of a bosonic D-brane. The holographic principle is a proposed duality which suggests that a theory in any region has a dual description on the boundary. We explore two examples: (1) The area law for the entropy of a black hole in the framework of loop quantum gravity, related to particular regularizations of the area operator. (2) The AdS/CFT correspondence proposal, where we investigate a string pulsating on AdS using spin chains. Theoretical physics theoretical physics string theory D-branes dualities AdS/CFT spin chains Bethe ansatz boundary conformal field theory conformal bootstrap tachyon condensation string field theory loop quantum gravity black holes area spectrum Hawking radiation holographic principle Teoretisk fysik Physics Fysik

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