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Muñiz, García Claudia. "Rapid Energy Transfer to an Energy Buffer". Thesis, KTH, Kommunikationssystem, CoS, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-91941.
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This master thesis introduces a new technology applicable to nearly all mobile and portable electrical devices since all of them need energy to operate. This thesis attempts to cut the last wire - this one the wire to the primary power source. In other words, fast and efficient wireless energy transference through a strong, focused near magnetic field whose fast attenuation will avoid interference with surrounding communication systems or human harm. This energy is transferred to and will be stored inside the mobile device where nothing but a small and simple secondary circuit has been placed. The thesis project began by creating an initial SPICE computer model, providing an easy and rapid way of testing both convergence and feasibility of the topology as the design evolved from the well-known and widely used Switch Model Power Supply technology through to the detailed design and implementation of the prototype, including supporting the iterative process of testing and optimizing, all stages are carefully described in the document. The thesis shows both theoretically and practically that this idea is feasible and capable of power transmission.Detta examensarbete introducerar en ny teknologi som är applicerbar till de flesta mobila och portabla elektriska apparater då dessa behöver energi för att fungera. Detta arbete försöker klippa den sista ledningen den som leder till den primära kraftkällan. Med andra ord, är denna teknik en snabb och effektiv trådlös energiöverföring genom ett starkt, fokuserat närbeläget magnetfält. Tack vare magnetfältets kraftiga dämpning undviks interferens med intilliggande kommunikationssystem eller personskador. Denna energi är överförd till, och lagras inuti en bärbar apparat där endast en liten och enkel sekundärkrets har placerats. Examensarbetsprojektet påbörjades med skapandet av en inledande SPICE datormodell. Modellen möjliggjorde ett enkelt och snabbt sätt att testa både konvergens och genomförbarhet av topologin samtidigt som designen utvecklades från den välkända och vitt använda Switch Power Supply-teknologin till den detaljerade designen och implementationen av prototypen. Modellen stöttade samtidigt den iterativa processen av test och optimering. Alla faser är utförligt beskrivna i rapporten och arbetet visar både teoretiskt och praktiskt att denna idé är genomförbar och möjliggör kraftöverföring.
2
Ortiz-Hernández, Wilfredo. "Energy transfer in dendrimers". [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0009300.
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Ortego, Javier Moreno. "Light-controlled energy transfer". Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät, 2015. http://dx.doi.org/10.18452/17263.
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Mit dem Ziel stabile und photomodulierbare Fluorophore für ihre direkte Anwendung in der hochaufgelösten Mikroskopie, wurde die Synthese und Charakterisierung von neuen fern Rot emittierender photoschaltbarer Fluorophore erreicht. Hierbei wurde die elektronische Kopplung zwischen den Komponenten tiefgreifend untersucht, und die Struktur Eigenschafts Beziehung etabliert. Durch die Wechselwirkung der photochromen Einheit mit dem Fluorophor, konnte die Fluoreszenzemission ein- und ausgeschaltet werden. Zusätzlich wurden Einkapselungs Experimente in Micellen durchgeführt, um die Wasserlöslichkeit der synthetisierten Verbindungen zu untersuchen. Letzlich, wurden mögliche Anwendungen mittels Fluoreszenzmikroskopie geprüft. Mit dem Ziel hochaufgelöste Bilder unter biologischen Bedingungen zu erhalten, wurde die Verkapselung der Dyaden in riesige unilamellare Vesikel erprobt. Unter Ausnutzung der Vorteile nichtlinearer Prozesse wurde die Synthese und Charakterisierung von photochromen Verbindungen, die in der Lage indirekt durch einen anfänglichen sensibilisierten Prozess geschaltet werden, untersucht. Zu diesem Zweck wurde ein Triarylamin Chromophor als Zwei-Photonenabsorber kovalent an einen Azobenzol verbunden. Die Charakterisierung der angeregten Zustandsdynamik wurde ausgeführt und die zwei Photonen induzierte Isomerisierung der Dyade bestätigt. Eine detaillierte Untersuchung der elektrochemischen Eigenschaften wurde durchgeführt und Richtlinien zur Verbesserung des Systems wurden kurz genannt.With the purpose of designing stable and photomodulable fluorophores for their direct application in subdiffraction microscopy techniques, the synthesis and characterization of new far-red emitting photoswitchable fluorophores was accomplished. Fluorescence emission was efficiently modulated or switched On and Off by the interaction of the photochromic unit with the fluorescent-unit. Additionally, encapsulation experiments in micelles were performed to investigate the water solubility of the synthesized compounds. Finally, potential applications were examined with fluorescence microscopy, encapsulating the dyads in giant uni-lamellar vesicles under biological conditions to explore the feasibility to obtain highly resolved subdiffraction images. Exploiting the advantages of nonlinear processes, the synthesis and characterization of photochromes which are able to be switched indirectly through an initial sensitized event were studied. With this determination a two-photon absorbing triarylamine chromophore was covalently linked to an electron poor azobenzene. In-depth characterization of the excited state dynamics was performed and two photon induced isomerization of the dyad was confirmed. A detailed study of the electrochemical properties was set and guidelines towards the improvement of the system were succinctly mentioned.
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Clarkson, Ian Michael. "Energy transfer in lanthanide complexes". Thesis, Durham University, 1999. http://etheses.dur.ac.uk/4498/.
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This thesis details investigations into the photophysical properties of lanthanide ions in a number of different systems. The preparation and characterisation of lanthanide containing surfactant salts of the type Ln(A0T)(_3) (Ln = Tb, Nd, Eu, AOT = bis-(2-ethylhexyl) sulfosuccinate) is described. Small angle neutron scattering experiments have been used to determine the size and shape of reverse micelles formed by these surfactants in water/cyclohexane microemulsions. The luminescence lifetimes of the lanthanide ions have been used to investigate the solvation environment within reverse micelle systems as a function of water content. The use of lanthanide complexes based on 1,4,7,10-tetraazacyclododecane bearing phenanthridine antenna in luminescence microscopy has been explored. Samples such as silica particles, onion skin cells and guinea pig heart cells have been imaged. Time- resolved measurements have allowed time gating of the sample from a fluorescent background and lifetime maps of the images have been obtained. The preparation and characterisation of deuteriated complexes of dota (1,4,7,10- tetraazacyclododecane-1,4,7,10-tetraacetic acid) with lanthanide ions is described. Selective deuteriation of both the ring and arm sites allow the relative quenching effects of C-H/D oscillators to be determined for various lanthanides in a series of structurally well defined complexes. Finally, investigations into the distance dependence of the energy transfer between aromatic chromophores and lanthanide ions have been undertaken. The synthesis of a model system linking a phenanthridine donor to a europium complex by poly(valine) spacer units is described. Preliminary photophysical results show that the quantum yield of emission by europium decreases as the distance between the donor acceptor pair is increased.
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Eley, C. D. "Energy transfer in unimolecular reactions". Thesis, University of Reading, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356079.
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Zhao, Pihong. "Nonradiative energy transfer in solutions". Scholarly Commons, 1994. https://scholarlycommons.pacific.edu/uop_etds/2807.
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Electronic excitation energy transfer from coumarins to xanthene dyes in different media has been investigated. Nonradiative energy transfer between coumarin 1 (d) and fluorescein (a), in 95% ethanol and in n-octanol takes place with critical transfer distances: 48.4 A (d-a) and 21.0 A (d-d) in 95% ethanol, and 46.4 A (d-a) and 25.4 A (d-d) in 1-octanol. The rate constants of nonradiative energy transfer and energy migration in these two solvents were compared with the rates of diffusion. Energy transfer in the three-component system coumarin 1/fluorescein/rhodamine B, was studied. The critical transfer distances between each two of the three components were: 48.4 A for coumarin 1/fluorescein; 42.2 A for coumarin 1/rhodamine B; and 65.5 A for fluorescein rhodamine B respectively. The quantitative description of this three component system indicates that, using our modified correction factors, the experimental data coincided satisfactorily with Kusba-Bojarski general equations of multi-component luminescence system. Nonradiative energy transfer between coumarin 6 and rhodamine 3B in poly-(methyl methacrylate) was studied. The fluorescence quantum yields of coumarin 6 in the monomer and polymer were measured to be 1.00 and 0.94 respectively. The calculated critical transfer distances were: 50.0 A (d-a) and 38.9 A (d-d) in the monomer; and 47.7 A (d-a) and 38.2 A (d-d) in the polymer. Unexpected high energy transfer efficiency was observed in the polymer. Environmental effects on the fluorescence of the fluorophore and the mechanism of energy transfer in fluid and rigid solutions were discussed. Fluorescence quantum yields of coumarin 1 in various alcohols were measured to be: 0.573 in 95% ethanol; 0.688 in ethanol; 0.826 in n-propanol; 0.814 in n-butanol; 0.818 in n-pentanol; 0.912 in n-hexanol; 0.846 in n-heptanol; 0.869 in n-octanol; 0.876 in n-nonanol and 0.882 in n-decanol. The fluorescence lifetimes of coumarin 1 in these alcohols, were calculated to be: 2.23; 3.20; 3.67; 3.42; 3.76; 3.47; 3.35; 3.88; 3.64; and 3.57 ns respectively. Solvent effects on the quantum yields were discussed.
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Yu, Shilin. "Reversible electronic energy transfer in rotaxane architectures". Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0127/document.
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L'objectif de cette thèse est la mise en place et l'étude d'un transfert d'énergie électronique réversible (REET), à la suite d’une excitation lumineuse, entre des sous-composants moléculaires au sein d’architectures nanométriques de type rotaxane. Dans un système bichromophorique, lorsque les états excités du chromophore les plus bas sont quasi-isoénergétiques et que la cinétique du transfert interchromophore est rapide, le REET peut être instillé en modifiant les propriétés de l'état excité. Des dérivés du pyrène et du tris(bipyridine)ruthénium(II) ont été choisis comme chromophores appariés. La formation de rotaxane a été catalysée par du cuivre (réactions de Huisgen et Cadiot-Chodkiewicz) au sein d’un macrocycle doté de pyrène, couplant des demi-fils moléculaires comprenant des groupements terminaux volumineux - dont Ru(bpy)32+. Des durées de vie de luminescence prolongée (jusqu'à 14 μs), comparées au parent Ru(bpy)32+, indiquent que des processus de transfert d'énergie électroniques réversibles ont été établis dans une série de rotaxanes de structure variable, sont étudiés par spectroscopies stationnaire et résolue dans le tempsThe focus of this thesis is the establishment and study of reversible electronic energy transfer (REET), following light excitation, between molecular subcomponents within ring-on-thread rotaxane nanometric architectures. When the lowest-lying chromophore excited states are quasi-isoenergetic and kinetics of interchromophore transfer are rapid, REET can be instilled - changing excited-state properties. Pyrene and ruthenium(II) tris(bipyridine) derivatives were chosen as matched chromophores. Rotaxane formation was based on active template copper catalysis (Huisgen and Cadiot-Chodkiewicz reactions) within a pyrene-decorated macrocycle, coupling half threads comprising bulky stopper groups - one of which being Ru(bpy)32+. Prolonged luminescence lifetimes (up to 14 μs), compared to parent Ru(bpy)32+, indicated that reversible electronic energy transfer processes were instilled in a series of rotaxanes of varying structure, which were studied by state-state and time-resolved spectroscopies
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Westlund, Arvid, i Oskar Bernberg. "Efficient Energy Transfer for Wireless Devices". Thesis, Uppsala universitet, Fasta tillståndets elektronik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-177255.
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This project is intended to findsuitable circuit architecture forefficient power transmission where thepower supply is low.Two circuits will be built. The firstwill receive high AC which correspondsto the voltage created in a piezoelement once subjected to stress fromfoot steps It will deliver 3.3DC.The second circuit will receive low ACwhich will represent voltage receivedfrom a wireless transfer.Due to a failing high voltage powersupply the second circuit was never putto practice. The idea was to send a wavefile through an OP-amplifier to simulatethe voltage from the piezo element. Thevoltage was then rectified and convertedto 3.3DC.Circuit 2 was tested with a frequencygenerator as power supply. The voltagewas transformed, rectified and at lastconverted to 3.3DC through a voltageregulator. Due to lack of deliveredpower from the frequency generator itwas necessary to duty cycle the load tolimit the power dissipation.The power dissipation in the voltageregulator was limited as well byswitching it on and off. When switchedoff a capacitor was charged. When in onmode the capacitor was emptied into thevoltage regulator.Det här projektet är ämnat att hittalämpliga kretsarkitetkturer för braeffektöverföring där energikällorna ärmycket begränsade.Två kretsar ska byggas. Den första skata emot hög växelspänning motsvarandespänningen som uppkommer i ettpiezoelement vilket utsätts för växlandetryck. I det här fallet trycket från enmänniskas fotsteg. Kretsen ska leverera3.3V likspänning.Den andra kretsen ska ta emot en lågväxelspänning, vilken motsvarar spänningfrån en trådlös överföring, och leverera3.3V.Krets 1 blev aldrig testad på grund avett fallerande högspänningsaggregat.Genom att skicka en wav-fil genom en OPförstärkareskulle en simulerad spänningfrån piezoelementet användas. Därefterskulle spänningen likriktas ochkonverteras ner till 3.3V.Krets 2 testades med en signalgeneratorsom spänningskälla. Spänningentransformerades först upp innan denlikriktades och skickades in i enspänningsreglator för att därefter ge ut3.3V. Med en liten levererad effekt frånsignalgeneratorn var det nödvändigt attbegränsa effektåtgången i lasten genompulsbreddmodulering. Effektåtgången ispänningsreglatorn begränsades ocksågenom att stänga av och på IC:n(spänningsregulatorn). När IC:n varavstängd laddades en kondensator upp somsedan tömdes i IC:n då den aktiveradesigen.
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Quacquarelli, Francesca Paola. "Energy transfer in directly reconfigurable nanomachines". Thesis, University of Sheffield, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.632820.
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Gowrie, Sarah. "FTIR emission studies of energy transfer". Thesis, University of Oxford, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.531817.
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Schmid, Stephan Alexander. "Energy Transfer Processes in Organic Semiconductors". Thesis, University of Oxford, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.514986.
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Campbell, Maya. "Energy transfer processes in erbium elpasolites". Thesis, Birkbeck (University of London), 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265854.
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O'Neill, M. "Energy transfer in MGO : Cr'+'3". Thesis, University of Strathclyde, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382415.
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Rawi, Zaid. "Rotational energy transfer in polyatomic molecules". Thesis, University of Sussex, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390073.
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Paton, Keith Richard. "Electromagnetic energy transfer into carbon nanotubes". Thesis, University of Cambridge, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.608860.
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Moore, Evan Guy. "A macrocyclic scaffold for electronic energy transfer and photoinduced electron transfer /". St. Lucia, Qld, 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe17983.pdf.
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Armitage, Bruce Alan. "Photoinduced electron transfer, energy transfer and polymerization reactions in phospholipid membranes". Diss., The University of Arizona, 1993. http://hdl.handle.net/10150/186212.
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The differential physical properties found at different depths of a phospholipid membrane permit design of systems for vectorial reactions (which are not possible in isotropic solution). In the system described in Chapter IV, a hydrophobic electron donor (triphenylbenzylborate) binds to the membrane interior while a hydrophilic electron acceptor (a cyanine dye) binds to the surface. Irradiation with red light leads to vectorial electron flow via photoinduced electron transfer (PET), as monitored by fluorescence quenching and photobleaching techniques. The PET reaction efficiency is enhanced over the case where the donor and acceptor are present in water without membranes. In that case, strong dimeric complexes are formed which reduce the efficiency of PET by enhancing nonradiative decay modes for the dye (Chapter III). Addition of a porphyrin to the membrane surface extends the sensitivity of the system to blue light (Chapter V). Excitation of the porphyrin at 417 nm and subsequent energy transfer to the cyanine trigger the same PET chemistry observed with red-light irradiation. Furthermore, the electron- and energy-transfer reactions are enhanced on polymerized, phase-separated membranes (Chapter VI). In these applications, membranes are media for chemical reactions. Membranes also make interesting substrates for chemical reactions, in this case, polymerization. A system consisting of a membrane-bound, amphiphilic cyanine dye and molecular oxygen is described in Chapter VII which effectively initiates the polymerization of vesicles upon irradiation with visible light. Potential utility in drug delivery applications is discussed.
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Smith, Darrin Lee. "Energy-transfer, electron-transfer, and atom/group-transfer resulting from low-energy ion-surface collisions characterize hydrocarbon, fluorocarbon, and mixed self-assembled monolayers". Diss., The University of Arizona, 2002. http://hdl.handle.net/10150/280208.
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Organic thin films (alkanethiolates chemisorbed on gold) were employed in low-energy (eV) ion-surface collisions to validate the technique as a surface analysis tool and to further investigate processes associated with ion-surface interactions. Low-energy ion surface collisions of small polyatomic and atomic ions with self-assembled monolayers (SAMs) ascertain the chemical composition, structure, and quality of SAMs utilizing four processes: energy transfer (fragmentation of projectile ions: surface-induced dissociation (SID)), electron transfer (neutralization of the projectile ions), atom/group transfer (reaction between the projectile ion and atom/groups from SAMs), and chemical sputtering. Low-energy ion-surface collisions were used to investigate newly synthesized fluorinated compounds where the degree of fluorination of the thiolate tail group increases. Data indicate that substitution of CH₃ with CF₃ as the terminal group has a substantial influence on energy transfer, electron transfer, and atom/group transfer. Slight penetration into a depth of SAM films is illustrated by the formation of certain ion-surface reaction products (a result not observed for previously characterized Langmuir-Blodgett (L-B) films). A novel neutralization mechanism for reaction between methyl cation and hydrocarbon and fluorocarbon SAMs was established. Ion neutralization (besides direct electron transfer) results from a hydride ion transfer, methyl anion transfer, or fluoride transfer between hydrocarbon and fluorocarbon SAMs and incoming methyl cations. Experimental ion-surface and ion-molecule data support the ion neutralization mechanism originally proposed by ab initio and thermochemical calculations. Ion-surface processes were also used to characterize three mixed SAM systems (system 1: hydroxyl/hydrocarbon mixed SAMs and systems 2 and 3: fluorocarbon/hydrocarbon mixed SAMs). The mixed SAMs were prepared from binary thiol solutions and uniform solutions of asymmetrical disulfides. These ion-surface data can be useful for qualitative (identification of the sample's chemical composition) and quantitative analysis (calculation of the surface concentration of a chemical species for a mixed SAM). An in-line Sector-Time-of-Flight (TOF) tandem mass spectrometer with low-energy ion-surface collisions was characterized. Research involved testing the versatility of the instrument in terms of effective ion activation (peptide fragmentation) and surface analysis of organic thin films. This prototype will aid further implementation of SID into commercial TOF instruments for efficient ion activation and surface analysis capabilities.
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Kang, Ji-Hwan. "Energy transfer enhancement of photon upconversion systems for solar energy harvesting". Thesis, Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/45846.
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Photon energy upconversion (UC), a process that can convert two or more photons with low energy to a single photon of higher energy, has the potential for overcoming the thermodynamic efficiency limits of sunlight-powered devices and processes. An attractive route to lowering the incident power density for UC lies in harnessing energy transfer through triplet-triplet annihilation (TTA). To maximize energy migration in multicomponent TTA-assisted UC systems, triplet exciton diffusivity of the chromophores within an inert medium is of paramount importance, especially in a solid-state matrix for practical device integration.
In this thesis, low-threshold sensitized UC systems were fabricated and demonstrated by a photo-induced interfacial polymerization within a coaxial-flow microfluidic channel and in combination with nanostructured optical semiconductors. Dual-phase structured uniform UC capsules allow for the highly efficient bimolecular interactions required for TTA-based upconversion, as well as mechanical strength for integrity and stability. Through controlled interfacial photopolymerization, diffusive energy transfer-driven photoluminescence in a bi-molecular UC system was explored with concomitant tuning of the capsule properties. We believe that this core-shell structure has significance not only for enabling promising applications in photovoltaic devices and photochromic displays, but also for providing a useful platform for photocatalytic and photosensor units.
Furthermore, for improving photon upconverted emission, a photonic crystal was integrated as an optical structure consisting of monodisperse inorganic colloidal nanoparticles and polymer resin. The constructively enhanced reflected light allows for the reuse of solar photons over a broad spectrum, resulting in an increase in the power conversion efficiency of a dye-sensitized solar cell as much as 15-20 %.
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Simonson, Carey James. "Heat and moisture transfer in energy wheels". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0014/NQ27431.pdf.
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Karhu, Robin. "Targeted Energy Transfer in Bose-Einstein Condensates". Thesis, Linköpings universitet, Teoretisk Fysik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-98279.
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Targeted Energy Transfer is a resonance phenomenon in coupled anharmonic oscillators. In this thesis we investigate if the concept of Targeted Energy Transfer is applicable to Bose-Einsteain condensates in optical lattices. The model used to describe Bose-Einstein condensates in optical lattices is based on the Gross-Pitaevskii equation. Targeted Energy Transfer in these systems would correspond to energy being transferred from one lattice site to another. We also try to expand the concept of Targeted Energy Transfer to a system consisting of three sites, where one of the sites are considered a perturbation to the system. We have concluded that it is possible to achieve Targeted Energy Transfer in a three-site system. The set-up of the system will in some of the cases studied lead to interesting properties, such as more energy being transferred to the acceptor site than what was initially localized on the donor site.
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Raszewski, Grzegorz [Verfasser]. "Energy transfer in Photosystem II / Grzegorz Raszewski". Berlin : Freie Universität Berlin, 2008. http://d-nb.info/1023260182/34.
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Joseph, Daphne Melissa Thow. "Energy and electron transfer in Photosystem Two". Thesis, Imperial College London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362720.
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Andrew, Jeremy James. "Energy transfer in gases and cryogenic liquids". Thesis, University of Oxford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303566.
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Wilson, Graham John. "Energy transfer in gases and cryogenic liquids". Thesis, University of Oxford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239254.
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Borbas, K. Eszter. "Switchable luminescent probes using resonance energy transfer". Thesis, Open University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.412386.
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Klaassen, Jody J. (Jody Jon). "Energy transfer processes in methane and trideuteromethan". Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/17368.
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Bavetta, Ryan A. (Ryan Andrew). "An investigation of didactic energy transfer systems". Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/40399.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.Includes bibliographical references (leaf 24).
New experiments were developed for the freshmen seminar Physics of Energy. The class covers electricity generation and dissipation, and provides experience in analysis and design of electrical and mechanical engineering systems. There was interest in developing a series of new laboratory experiments that would demonstrate methods of energy conversion to students. The experiments are focused on the topic of energy conversion and they introduce topics from electromagnetism to mechanical engineering. The new systems developed include a DC motor kit for learning about motor design and use, a linear synchronous motor for learning about electromagnetism, classical mechanics and ballistics, and an end to end power plant energy conversion laboratory to introduce the topics of heat transfer and process efficiencies.
by Ryan A. Bavetta.
S.B.
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Boothby, Clare Elspeth. "Phosphorescence and energy transfer in organometallic systems". Thesis, University of Cambridge, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.614800.
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Torres, Garcia Juan de. "Nanophotonic control of Förster resonance energy transfer". Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4354.
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Le transfert d'énergie par résonance de type Förster (FRET) permet de mesurer des distances nanométriques grâce à la dépendance critique de l'efficacité du transfert avec la séparation entre un donneur et un accepteur d'énergie. Le phénomène se produit quand le fluorophore donneur dans l'état excité transfère son énergie d'excitation à un accepteur à proximité de façon non-radiative avec une interaction dipôle-dipôle de champ proche. Les structures nanophotoniques sont capables de contrôler cette interaction grâce à la modification de la densité local d'états électromagnétiques (LDOS) d'un émetteur quantique. Nous avons démontré clairement l'exaltation du transfert d'énergie des paires FRET individuelles sous l'influence des nano-ouvertures percées en or et en aluminium et aussi à l'aide des designs plus complexes comme la `` antenna-in-box ". Notamment, nous avons dévoilé l'importance essentielle de l'orientation relative entre les dipôles sur les possibilités d'exaltation du transfert d'énergie par le biais des nanostructures. Également, nous avons utilisé des nanofils en argent pour démontrer un transfert d'énergie de long-distance entre deux nanoparticles séparées de plus d'un micromètre. Nos résultats éclairent le chemin de l'exploration du FRET, qui est largement utilisé dans les sciences du vivant et la biotechnologie. Les nanostructures optiques ouvrent de plus des perspectives d'applications innovantes pour la construction de biocapteurs, de sources de lumière ou dans l'industrie photovoltaïqueThe technique of Förster resonance energy transfer (FRET) determines the separation between two molecules at the nanometer scale, where molecular interactions can take place. The phenomenon requires a donor fluorophore transferring its energy in a non-radiative way, through a near-field dipole-dipole interaction, to an acceptor. Nanophotonics achieves accurate control over these interactions by modifying the local density of optical states (LDOS) of a single quantum emitter. We have clearly demonstrated enhanced energy transfer within single FRET pairs confined in single nanoapertures made of gold and also aluminum or in more complex structures like the antenna-in-box design. In particular, we have revealed the strong influence of the mutual dipole orientation on the FRET enhancement using nanostructures. Also, by means of silver nanowires, we have demonstrated a long-range plasmon-mediated fluorescence energy transfer between two nanoparticles separated by micrometer distance. Our results are clearing a new path to improve the energy transfer process widely used in life sciences and biotechnology. Optical nanostructures open up many potential applications for biosensors, light sources or photovoltaics
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Al-Ahmadi, Ameenah N. "EXCITATION ENERGY TRANSFER IN QUANTUM-DOT SOLIDS". Ohio University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1146849631.
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Leopold, Matthew. "Förster Resonance Energy Transfer in PbS Films". Bowling Green State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1408656943.
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Ball, Christopher D. "Rotational energy transfer in low temperature molecules /". The Ohio State University, 1998. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487951214940079.
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Duarte, Rute Catarina Batista de Carvalho. "Materials for energy: opportunities for technology transfer". Master's thesis, Universidade de Aveiro, 2011. http://hdl.handle.net/10773/7567.
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Mestrado em Engenharia QuímicaEnergy is a current topic and although due to different motivations (rising fuel costs, environmental issues or supply security) the main goals are common, consume less energy and find alternatives to fossil fuel based technologies. Nowadays, significant efforts towards the implementation of sustainable energy technologies, by delineating strategies and priorities, as well as through developing supporting mechanisms and building scenarios. In Europe this efforts are being taken in order to meet the ambitious and binding energy and climate change objectives for 2020. In the form of electricity, heat, light, mechanical, biological or chemical, energy will become an always more expensive commodity, and therefore there is a great need to manage this resource effectively. New products made from new advanced materials can have a large impact on the energy field. It is intended with this dissertation to better understand the energy problem nowadays, to explore applicability of materials science towards sustainable energy technologies with potential to commercial deployment and to understand in each way the positioning of the University of Aveiro associate laboratory CICECO – Centre for Research in Ceramics and Composites Materials, the largest Portuguese institute in the field of materials science and engineering, is fulfilling these assumptions. Therefore, this analysis aims at gathering information in order to create a tool for strategic decision making.
A energia é uma temática atual e, apesar das diferentes motivações (o aumento do consumo de combustíveis, as questões ambientais ou de segurança de abastecimento), os principais objetivos são comuns, reduzir o consumo de energia e encontrar formas de energia alternativas aos combustíveis fósseis. Actualmente estão a ser desenvolvidos esforços significativos no sentido da implementação de tecnologias de energia sustentável, delineando para tal estratégias e prioridades, assim como desenvolvendo mecanismos de financiamento e projecção de cenários. Na Europa, estes esforços estão a ser desenvolvidos no sentido de cumprir com os objectivos ambiciosos estabelecidos para 2020, no que respeita a energia e às alterações climáticas. Sob a forma de electricidade, calor, luz, mecânica, biológica ou química, a energia vai se tornar uma comodidade cada vez mais cara e, neste sentido, há uma grande necessidade de gerir este recurso de forma eficaz. Novos produtos resultantes do desenvolvimento de novos materiais avançados poderão ter um impacto significativo na área da energia. Pretende-se com esta dissertação analisar a atual problemática energética, explorar a aplicabilidade da ciência dos materiais em tecnologias energéticas sustentáveis com potencial de comercialização e perceber de que forma o posicionamento do Laboratório Associado da Universidade de Aveiro, CICECO - Centro de Investigação em Materiais Cerâmicos e Compósitos, o maior instituto Português em matéria de engenharia e ciência dos materiais, vai ao encontro desses pressupostos. Deste modo, a presente análise pretende reunir informação de forma a criar uma ferramenta de apoio à decisão em termos de desenvolvimento estratégico.
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Megow, Jörg. "Excitation energy transfer in pheophorbide a complexes". Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2013. http://dx.doi.org/10.18452/16673.
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Die Arbeit untersucht den Anregungsenergietransfer in supramolekularen Phäophorbid-a-Komplexen. Das P4- und das P16-Molekül bestehen aus vier bzw. sechzehn Phäophorbid-a-Molekülen. Die Komplexe werden in explizitem Lösungsmittel im Rahmen einer gemischt quanten-klassischen Methode untersucht. Klassische Molekulardynamik-Simulationen werden durchgeführt. Die zeitabhängige Schrödingergleichung wird gelöst, der entsprechende Hamiltonoperator hängt parametrisch von den Kernkoordinaten ab. Es wird eine Methode vorgestellt, die die Berechnung des Schwingungsbeitrags der Koordinatenabhängigkeit in harmonischer Näherung ermöglicht. Die Qualität der Methode wird bewiesen. Es werden drei verschiedene Ansätze benutzt, um das Zeitverhalten des Anregungsenergietransfers innerhalb der Chromophorkomplexe zu charakterisieren. Es werden zunächst Transferraten berechnet und entsprechende Ratengleichungen gelöst. Desweiteren werden gemittelte zeitabhängige Populationen aus der Lösung der Schrödingergleichung bestimmt. Zudem wird die Zeitskala des Anregungsenergietransfers aus der Anisotropie erhalten. Die Berechnung der Anisotropie beruht auf der Lösung einer Schrödingergleichung, welche das elektromagnetischen Feldes explizit enthält. Für alle drei Ansätze ergibt sich die gleiche Dynamik des Anregungsenergietransfers. Es werden zudem lineare und transiente Spektren der Qy-Banden der Chromophorkomplexe berechnet. Für ein einzelnes Phäophorbid-a-Molekül in Ethanol werden zusätzlich die Qx-Bande und die Schwingungsprogression bestimmt. Außerdem wird die lineare Absorption von Phäophorbid a und P16 neben einem Gold-Nanopartikel untersucht, die erwartete Verstärkung des Absorptionssignals durch die Präsenz des Nanoteilchens wird gezeigt. Abschließend wird eine neue Methode vorgestellt, die es erlaubt, die abstands- und orientierungsabhängige Abschirmung der exzitonischen Kopplung parametrisch in die gemischt quanten-klassische Methode zu integrieren.This thesis investigates the excitation energy transfer in pheophorbide a complexes. The P4 and the P16 molecule consist of four and sixteen pheophorbide a molecules, respectively. The complexes in explicit ethanol solution are investigated utilizing a mixed quantum-classical methodology. Classical molecular dynamics simulations are carried out. The time-dependent Schrödinger equation is solved for a Hamiltonian that depends parametrically on the classical nuclear coordinates. In this thesis a method is introduced which allows the computation of the vibrational contribution in harmonic approximation. The high quality of the method is proven. Three different ansatzes were utilized to compute the time development of the excitation energy transfer within the chromophore complexes. The expansion coefficients that result from the solution of the time-dependent Schrödinger equation are utilized to compute averaged time-dependent populations. Also, the expansion coefficients are used to compute excitation energy transfer rates in second order of the excitonic coupling. Thirdly, the time scale of the excitation energy transfer is derived from the delay-time dependent transient anisotropy. In order to compute the anisotropy, the electromagnetic field is included directly in the Hamiltonian of the system. The excitation energy transfer dynamics is exactly the same for the three approaches. In addition, linear and transient spectra of the chromophor complexes Qy band are computed. For a single pheophorbide a in ethanol, the Qx band and the vibrational progression are calculated. Furthermore, the linear absorption of pheophorbide a and P16 next to a gold nanoparticle is studied. The amplification of the molecular absorption signal due to the presence of the nanoparticle is shown. Finally, a new method is introduced to treat distance and conformation dependent screening of the excitonic coupling parametrically within a mixed quantum-classical description.
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Bianchi, Francesco. "Energy Transfer in Organic-Inorganic Semiconductor Structures". Doctoral thesis, Humboldt-Universität zu Berlin, 2018. http://dx.doi.org/10.18452/19286.
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In HIOS-Strukturen, die auf einem Quantengraben und einer angrenzenden organischen Deckschicht basieren, wurde eine effiziente Umwandlung von Wannier-Exzitonen in Frenkel-Exzitonen mittels resonantem Förster Energietransfer (FRET) demonstriert.
Das hier verwendete Design besteht aus einem spiro-annulierten Quarter-phenyl (L4P-SP3), das auf einen ZnO-Quantengraben (SQW) aufgewachsen wurde, um inkohärente Kopplung zu erreichen.
Mittels optischer Spektroskopie haben wir demonstriert, dass diese hybriden Strukturen Energietransfer vom SQW zu den organischen Molekülen mit einer Effizienz von bis zu 77% zeigen. Allerdings zeigen UPS-Messungen eine typ-II-artige Energieniveau-Anpassung zwischen ZnO und der molekularen Schicht, die zu einem sehr effizienten Ladungstrennungsvorgang (ηCT=0.9) führt, der die molekulare Emission unterdrückt.
Die erste beruht auf einer schnellen und hocheffizienten Energietransfer-Kaskade: nach der ersten Transferstufe wird die Anregungsenergie von der hybriden Grenzfläche weggeleitet, indem eine zweite Energietransferstufe eingeführt wird, bevor die Dissoziation der Exzitonen an der Grenzfläche statt-finden kann. Wir verwenden Sexiphenyl, L6P als endgültigen Akzeptor. In solch einer Struktur können wir eine Wiederherstellung der molekularen Emission um einen Faktor acht demonstrieren und zeigen, dass der Energietransferprozess zwischen L4P-SP3 und L6P den Ladungstrennungsprozess fast vollständig überholt.
Als andere Option haben wir die Energieniveaus angepasst, indem eine organometallische Donor-Monolage [RuCp*mes] ergänzt wird. Diese Zwischenschicht senkt die Austrittsarbeit von ZnO deutlich ab und führt so zu einer Anpassung der Niveaus zwischen die zwei Halbleiter. Während die Effizienz des Energietransfers unverändert bleibt, steigen die Emission von L4P-SP3 sowie die Lebenszeit der molekularen Photoluminescenz um einen Faktor sieben verglichen mit entsprechenden Strukturen ohne Zwischenlage.In HIOS structures based on a quantum well and an adjacent organic overlayer, efficient conversion of Wannier excitons into Frenkel excitons via Förster-type resonant energy transfer (FRET) has been demonstrated. The design here in use consists of a spiro-annulated ladder-type quarter-phenyl (L4P-SP3), deposited on ZnO-based single quantum wells (SQW) to obtain incoherent electronic coupling. The SQWs we use are grown with extremely thin (2 nm) capping layer. With photoluminescence excitation and time-resolved spectroscopy, we demonstrate that these hybrid structures exhibit energy transfer from the inorganic material to the organic molecules with an efficiency up to 77%. However, UPS measurements show a type-II energy level alignment between ZnO and the molecular layer, resulting in a very efficient charge separation process (ηCT=0.9) that suppresses the molecular emission. The first idea relies on a fast and highly efficient cascade FRET: following the primary transfer step from the QW, the excitation is conveyed away from the hybrid interface by a secondary transfer-step within the organic layer. As final acceptor we select ladder-type sexiphenyl (L6P). In such a structure, we demonstrate a recovery of the molecular emission by a factor eight, showing that the intermolecular FRET outpaced almost entirely the charge separation process. As alternative option, we tune the energy levels at the interface by introducing an organometallic donor monolayer [RuCp*mes]. The interlayer reduces substantially the ZnO work function, aligning the frontier levels of the inorganic and organic semiconductor. Optical experiments show the benefits of the interlayer: while the FRET efficiency is unaffected, the L4P-SP3 emission and its photoluminescence lifetime increase by a factor of seven, when compared to the same structure without interlayer.
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Czuprynski, Kenneth Daniel. "Numerical analysis in energy dependent radiative transfer". Diss., University of Iowa, 2017. https://ir.uiowa.edu/etd/5925.
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The radiative transfer equation (RTE) models the transport of radiation through a participating medium. In particular, it captures how radiation is scattered, emitted, and absorbed as it interacts with the medium. This process arises in numerous application areas, including: neutron transport in nuclear reactors, radiation therapy in cancer treatment planning, and the investigation of forming galaxies in astrophysics. As a result, there is great interest in the solution of the RTE in many different fields.
We consider the energy dependent form of the RTE and allow media containing regions of negligible absorption. This particular case is not often considered due to the additional dimension and stability issues which arise by allowing vanishing absorption. In this thesis, we establish the existence and uniqueness of the underlying boundary value problem. We then proceed to develop a stable numerical algorithm for solving the RTE. Alongside the construction of the method, we derive corresponding error estimates. To show the validity of the algorithm in practice, we apply the algorithm to four different example problems. We also use these examples to validate our theoretical results.
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Benco, John S. "Singlet-singlet and triplet-triplet energy transfer in polychromophoric peptides". Link to electronic thesis, 2000. http://www.wpi.edu/Pubs/ETD/Available/etd-0803100-103547.
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Zhang, Yufang. "Coupled convective heat transfer and radiative energy transfer in turbulent boundary layers". Phd thesis, Ecole Centrale Paris, 2013. http://tel.archives-ouvertes.fr/tel-00969159.
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If radiation plays an important role in many engineering applications, especially in those including combustion systems, influence of radiation on turbulent flows, particularly on the turbulent boundary layers, is still not well known. The objective is here to perform a detailed study of radiation effect on turbulent flows. An optimized emission-based reciprocal (OERM) approach of the Monte-Carlo method is proposed for radiation simulation using the CK model for radiative gas properties. OERM allows the uncertainty of results to be locally controlled while it overcomes the drawback of the original emission-based reciprocity approach by introducing a new frequency distribution function that is based on the maximum temperature of the domain. Direct Numerical Simulation (DNS) has been performed for turbulent channel flows under different pressure, wall temperatures and wall emissivity conditions. Flow field DNS simulations are fully coupled with radiation simulation using the OERM approach. The role of radiation on the mean temperature field and fluctuation field are analyzed in details. Modification of the mean temperature profile leads to changes in wall conductive heat fluxes and new wall laws for temperature when radiation is accounted for. The influence on temperature fluctuations and the turbulent heat flux is investigated through their respective transport equations whose balance is modified by radiation. A new wall-scaling based on the energy balance is proposed to improve collapsing of wall-normal turbulent flux profiles among different channel flows with/without considering radiation transfer. This scaling enables a new turbulent Prandtl number model to be introduced to take into account the effects of radiation. In order to consider the influence of radiation in the near-wall region and predict the modified wall law, a one-dimensional wall model for Large Eddy Simulation (LES) is proposed. The 1D turbulent equilibrium boundary layer equations are solved on an embedded grid in the inner layer. The obtained wall friction stress and wall conductive flux are then fed back to the LES solver. The radiative power term in the energy equation of the 1D wall model is computed from an analytical model. The proposed wall model is validated by a comparison with the former DNS/Monte-Carlo results. Finally, two criteria are proposed and validated. The first one is aimed to predict the importance of wall radiative heat flux while the other one predicts whether a wall model accounting for radiation in the near wall region is necessary. A parametric study is then performed where a k-ǫ model and a turbulent Prandtl number model are applied to simulate the velocity and temperature field of different channel flows under various flow conditions. The obtained criteria values are analyzed and compared.
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Ferguson, David C. "Intramolecular energy transfer in polychromophores that utilize peptide bridging groups". Link to electronic version, 2000. http://www.wpi.edu/Pubs/ETD/Available/etd-0505100-132458/.
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Herman, Leslie. "Ru(II) under illumination: a study of charge and energy transfer elementary processes". Doctoral thesis, Universite Libre de Bruxelles, 2008. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210399.
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Une compréhension sans cesse plus pointue des processus élémentaires de transferts de charges et d’énergie, qui sont à la base même de nombreux processus biologiques, permet non seulement l’élaboration mais aussi l’amélioration de la mise au point de molécules photoactives utiles dans différentes applications. C'est le cas (i) de systèmes moléculaires et supramoléculaires destinés à mimer efficacement la photosynthèse, ou encore (ii) de molécules photoactives capables d’interagir avec des macromolécules biologiques et d’induire une transformation de ces biomolécules. C’est dans ce cadre général que s’inscrit l’élaboration de nouveaux complexes polyazaaromatiques de Ru(II) capables d’interagir avec la double hélice d’ADN et de photoréagir avec sa base la plus réductrice, la guanine, par transfert d’électron photoinduit. C’est sur la base de ces processus que des nouveaux agents antitumoraux photoactivables ont pu être développés. L’utilisation de complexes de Ru(II) dans le design d’entités supramoléculaires polymétalliques destinées à jouer le rôle de collecteurs de lumière et permettant ainsi de mimer les systèmes d’antennes naturels s’intègre également dans cette démarche. L’ensemble de notre travail s’est concentré sur ces deux domaines d’applications. Par l’étude de différents processus de transfert de charges/d’énergie au sein des complexes seuls (processus intramoléculaires) ou en interaction avec un environnement spécifique (processus intermoléculaires), nous avons souhaité mettre en évidence l’intérêt de l’utilisation d’un nouveau ligand plan étendu, le tpac, au sein de complexes du Ru(II). Un tel ligand permet en effet de conférer d’une part une affinité élevée des complexes résultants pour l’ADN, et d’autre part, de par sa nature pontante, de connecter des unités métalliques entre elles au sein d’entités supramoléculaires de taille importante.
Les propriétés photophysiques de quatre complexes basés sur le ligand plan étendu tpac, le [Ru(phen)2tpac]2+ (P) et son homologue dinucléaire le [(phen)2Ru tpac Ru(phen)2]4+ (PP) (à base de ligands ancillaires phen), ainsi que le [Ru(tap)2tpac]2+ (T) et son homologue dinucléaire le [(tap)2Ru tpac Ru(tap)2]4+ (TT) (à base de ligands ancillaires tap), ont été étudiées et comparées entre elles.
L’examen de ces propriétés, d’abord pour les complexes seuls en solution, en parallèle avec celles de complexes dinucléaires contenant un ligand pontant PHEHAT, a permis de mettre en évidence l’importance de la nature du ligand pontant utilisé. Ces résultats ont ainsi révélé qu’un choix judicieux du ligand pontant permet de construire des entités de grande taille capables de transférer l’énergie lumineuse vers un centre (cas du ligand PHEHAT), ou, au contraire, de relier entre elles des entités ne s’influençant pas l’une l’autre d’un point de vue photophysique (cas du ligand tpac).
Les propriétés des complexes du tpac, étudiés cette fois en présence de matériel génétique (mononucléotide GMP, ADN ou polynucléotides synthétiques), se sont révélées très différentes selon que le complexe portait des ligands ancillaires phen (P, PP) ou tap (T, TT). Seuls les complexes à base de tap sont en effet photoréactifs envers les résidus guanine. Nous avons dès lors focalisé cette partie de notre travail sur les deux complexes T et TT. Cette photoréaction, ainsi que le transfert d’électron photoinduit entre ces complexes excités et la guanine, ont pu être mis en évidence par différentes techniques de spectroscopie d’émission tant stationnaire que résolue dans le temps, ainsi que par des mesures d’absorption transitoire dans des échelles de temps de la nano à la femto/picoseconde. L’étude du comportement photophysique des complexes en fonction du pH a en outre révélé de manière très intéressante que, pour des études en présence d’ADN, la protonation des états excités des complexes devait être considérée. Les résultats de cette étude nous ont fourni des pistes quant à l’attribution des processus observés en absorption transitoire.
Le transfert d’électron a également fait l’objet d’une étude par des méthodes théoriques. Ces calculs ab initio ont permis de mettre en évidence une faible influence de l’énergie de réorganisation sur la vitesse de transfert d’électron, qui semble dépendre plus sensiblement de la non-adiabaticité du processus, mais surtout de l’énergie libre de la réaction et d’un éventuel couplage à un transfert de proton.
L’ensemble des résultats obtenus avec les complexes T et TT en présence de matériel génétique, qui, de manière assez inattendue, sont très semblables, indiquent que ces complexes présentent tous deux un grand intérêt pour le développement de nouvelles drogues antitumorales photoactivables.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
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Tran, Thu-Trang. "Electron and multielectron reaction characterizations in molecular photosystems by laser flash photolysis, towards energy production by artificial photosynthesis". Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS320.
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La demande énergétique de l’humanité augmente rapidement et ne montre aucun signe de ralentissement. Parallèlement à cette problématique, l'utilisation abusive de combustibles fossiles est l'une des principales causes d'augmentation de la concentration de CO₂ dans l'atmosphère. Ces problèmes doivent être résolus en termes de limitation des émissions de CO₂ et de recherche de sources d'énergie renouvelables pour remplacer les combustibles fossiles. De nos jours, l’énergie solaire est l’une des sources d’énergie renouvelables les plus efficaces. La conversion de l'énergie de la lumière solaire en électricité dans le photovoltaïque ou en énergie chimique par le biais de processus photocatalytiques implique invariablement un transfert d'énergie photo-induit et un transfert d'électrons. Dans ce contexte, l'objectif de la thèse est d'étudier les processus photo-induits dans les photosystèmes moléculaires utilisant la photolyse par flash laser. Le premier thème de cette thèse porte sur l’étude du transfert monoélectronique dans des systèmes de dyades donneur-accepteur en vue d’optimiser l’efficacité de la séparation des charges et de son application dans la cellule solaire organique photovoltaïque. Le deuxième thème de cette thèse porte sur l’étude de deux systèmes modèles de photosynthèse artificielle étudiés pour la possibilité d’une accumulation de charge par étapes. Ensuite, différents systèmes photocatalytiques, développés pour la photoréduction du CO₂, ont été étudiés. La compréhension des processus photo-induits devraient permettre l’amélioration de l'efficacité de la réduction du CO₂ dans les systèmes photocatalytiques pratiquesThe energy demand of humanity is increasing rapidly, and shows no signs of slowing. Alongside this issue, abuse using fossil fuels is one of the main reasons which leads to an increase in atmospheric CO₂ concentration. These problems have to be solved in terms of both limiting CO₂ emission and finding renewable energy sources to replace fossil fuels. Nowadays, solar energy appears as one of the most effective renewable energy sources. Conversion of solar light energy to electricity in photovoltaics or to chemical energy through photocatalytic processes invariably involves photoinduced energy transfer and electron transfer. In this context, the aim of the thesis focuses on studying photoinduced processes in molecular photosystems using laser flash photolysis. The first theme of this thesis focus on studying single electron transfer in Donor-Acceptor Dyad systems towards optimization efficiency of charge separation and application in the photovoltaic organic solar cell. In the second theme of this thesis, two model systems of artificial photosynthesis were investigated to assess the possibility of stepwise charge accumulation on model molecules. A fairly good global yield of approximately 9% for the two charge accumulation on MV²⁺ molecule was achieved. Then, different photocatalytic systems, which have developed for CO₂ reduction, were studied. Understanding of the photoinduced processes is an important step toward improving the efficiency of reduction of CO₂ in practical photocatalytic systems
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Basu, Soumyadipta. "Near-field radiative energy transfer at nanometer distances". Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/31777.
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Thesis (Ph.D)--Mechanical Engineering, Georgia Institute of Technology, 2010.Committee Chair: Zhang, Zhuomin; Committee Member: Citrin, David; Committee Member: Hesketh, Peter; Committee Member: Joshi, Yogendra; Committee Member: Peterson, Andrew. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Momeneh, Arash. "Inductive contactless energy transfer systems for residential areas". Doctoral thesis, Universitat Politècnica de Catalunya, 2016. http://hdl.handle.net/10803/462809.
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In recent years, contactless energy transfer systems have been developed and investigated widely. As evident, the transfer energy is performed without physical connection. This technology is classified according to power level and place of use. However, the most commonly used one is inductive contactless energy transfer system due to its higher efficiency. The inductive contactless system is responsible to deliver the electrical energy to the loads by means of a long winding loop and sliding transformers. In this system, the output converter and load are directly connected to the secondary side of transformer. Moreover, the secondary side transformer has the capability to move along the primary winding loop. According to this capability, and also possibility to construct long contactless system, it can be used as an electrical energy delivery system for mobile receivers. Also, the ICET technologies improve the safety of the final user by means of the elimination of electrical shocks. It is resulted from using a high-frequency resonant transformer which provides electrical isolation. This feature is particularly important in wet environments such as in swimming pools, gardens and bathrooms. Therefore, it is a good alternative system for implementing in the residential area instead of conventional systems.
Implementation of the inductive contactless system in residential area presents several challenges. In this dissertation, several solutions are presented and discussed. In the first chapter, the concept of the contactless energy transfer system is explained. Also, the chapter classifies the contactless system according to the technology and the output power. In chapter two, a new adaptive control algorithm for the fully-controlled contactless energy transfer system is presented. The new adaptive algorithm operates dynamically with the load changes, resulting in maximum efficiency in all the load conditions. Moreover, the mathematical framework of the contactless system with new adaptive algorithm is presented. In chapter three, a partially-controlled inductive contactless system as an alternative to the fully-controlled topology is introduced. The features of the new topology are analyzed by considering several modulation techniques, including frequency modulation, phase modulation and quantum modulation. The performance of the new topology is evaluated and the best modulation technique is identified. The chapter is finished with the design of the new topology with the best modulation technique. In chapter four, the analysis, design and implementation of a simple and cost-effective technique to supply the residential contactless energy transfer system with multiple mobile loads is presents. The topology is based on the cascaded connection of a closed-loop buck converter and a high frequency resonant inverter operating in open loop which is loaded by several output passive rectifiers. The proposed system includes a sliding transformer to supply the mobile loads, leading to a safe and flexible location of loads. The theoretical analysis and design of the proposed system is based on a mathematical model derived using the first harmonic approximation. Selected experimental results are included to verify the system features. Finally, the dissertation concludes with remarks regarding the results.En los últimos años, los sistemas de transmisión de energía sin contacto han sido ampliamente investigados y desarrollados. Como es evidente, en estos la transmisión de energía se realiza sin conexión física. Esta tecnología se suele clasificar de acuerdo al nivel de potencia y el lugar de utilización. Sin embargo, los más usados son los sistemas inductivos de trasmisión de energía sin contacto (Inductive contactless energy transfer systems, ICET) debido a su alta eficiencia. Los sistemas ICET envían la energía eléctrica a las cargas a través de grandes bobinados y transformadores sliding. En estos sistemas, la salida del convertidor y las cargas están directamente conectadas al lado secundario del transformador. Este, tiene la capacidad de moverse a través del bobinado primario. Debido a esta capacidad y a la posibilidad de construir sistemas de gran tamaño, pueden ser usados como sistemas de suministro de energía para receptores móviles. Por otro lado, las tecnologías ICET mejoran la seguridad de los usuarios finales ya que eliminan el riesgo de electrocución, como resultado del uso de transformadores resonantes de alta frecuencia que proveen un aislamiento eléctrico. Esta característica es particularmente importante en ambientes húmedos como las piscinas, jardines y baños. Además, es una buena alternativa para la implementación residencial, en lugar de los sistemas convencionales. La implementación de sistemas ICET en áreas residenciales presenta ciertos retos. En esta tesis de doctorado, se presentan diversas soluciones a estos. En el primer capítulo, el concepto de sistemas de transmisión de energía sin contacto es explicado y se presenta una clasificación de acuerdo al nivel de potencia. En el segundo capítulo, se propone un algoritmo de control adaptativo para sistemas de transmisión de energía sin contacto totalmente controlados. Este algoritmo adaptativo opera dinámicamente con los cambios de carga, alcanzando la máxima eficiencia ante diferentes condiciones de carga. En el capítulo se describe el modelado matemático del algoritmo propuesto. En el tercer capítulo, se introduce un sistema sin contacto inductivo parcialmente controlado como alternativa a la topología totalmente controlada. Se analizan las características de esta nueva topología considerando diferentes técnicas de modulación, incluyendo la modulación de frecuencia, la modulación de fase y la modulación Quantum. Luego, se evalúa el desempeño de esta nueva topología y de identifica la técnica de modulación más adecuada. Finalmente, se presenta el diseño de la nueva topología con la técnica de modulación seleccionada. En el cuarto capítulo se presenta el análisis, diseño e implementación de una técnica simple y efectiva en términos de costo para el suministro energía inalámbrica residencial con múltiples cargas móviles. La topología se basa en una conexión en cascada de un convertidor buck de lazo cerrado y de un inversor resonante de alta frecuencia operando en lazo abierto, que es cargado con varios rectificadores pasivos. El sistema propuesto incluye un transformador sliding para abastecer las cargas móviles, lo que permite una ubicación flexible y segura de las mismas. El análisis teórico y el diseño del sistema propuesto se basan en modelos matemáticos derivados del uso de la aproximación del primer armónico. Se incluyen resultados experimentales para verificar las características del sistema. Finalmente, se presentan las conclusiones más importantes de los resultados obtenidos
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Piovesan, Nicola. "Network resource allocation policies with energy transfer capabilities". Doctoral thesis, Universitat Politècnica de Catalunya, 2020. http://hdl.handle.net/10803/669313.
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During the last decades, mobile network operators have witnessed an exponential increase in the traffic demand, mainly due to the high request of services from a huge amount of users. The trend is of a further increase in both the traffic demand and the number of connected devices over the next years. The traffic load is expected to have an annual growth rate of 53% for the mobile network alone, and the upcoming industrial era, which will connect different types of devices to the mobile infrastructure including human and machine type communications, will definitely exacerbate such an increasing trend.
The current directions anticipate that future mobile networks will be composed of ultra dense deployments of heterogeneous Base Stations (BSs), where BSs using different transmission powers coexist. Accordingly, the traditional Macro BSs layer will be complemented or replaced with multiple overlapping tiers of small BSs (SBSs), which will allow extending the system capacity. However, the massive use of Information and Communication Technology (ICT) and the dense deployment of network elements is going to increase the level of energy consumed by the telecommunication infrastructure and its carbon footprint on the environment.
Current estimations indicates that 10% of the worldwide electricity generation is due to the ICT industry and this value is forecasted to reach 51% by 2030, which imply that 23% of the carbon footprint by human activity will be due to ICT. Environmental sustainability is thus a key requirement for designing next generation mobile networks.
Recently, the use of Renewable Energy Sources (RESs) for supplying network elements has attracted the attention of the research community, where the interest is driven by the increased efficiency and the reduced costs of energy harvesters and storage devices, specially when installed to supply SBSs. Such a solution has been demonstrated to be environmentally and economically sustainable in both rural and urban areas. However, RESs will entail a higher management complexity. In fact, environmental energy is inherently erratic and intermittent, which may cause a
fluctuating energy inflow and produce service outage. A proper control of how the energy is drained and balanced across network elements is therefore necessary for a self-sustainable network design.
In this dissertation, we focus on energy harvested through solar panels that is deemed the most appropriate due to the good efficiency of commercial photovoltaic panels as well as the wide availability of the solar source for typical installations. The characteristics of this energy source are analyzed in the first technical part of the dissertation, by considering an approach based on the extraction of features from collected data of solar energy radiation.
In the second technical part of the thesis we introduce our proposed scenario. A federation of BSs together with the distributed harvesters and storage devices at the SBS sites form a micro-grid, whose operations are managed by an energy management system in charge of controlling the intermittent and erratic energy budget from the RESs. We consider load control (i.e., enabling sleep mode in the SBSs) as a method to properly manage energy inflow and spending, based on the traffic demand. Moreover, in the third technical part, we introduce the possibility of improving the network energy efficiency by sharing the exceeding energy that may be available at some BS sites within the micro-grid.
Finally, a centralized controller based on supervised and reinforcement learning is proposed in the last technical part of the dissertation. The controller is in charge of opportunistically operating the network to achieve efficient utilization of the harvested energy and prevent SBSs blackout.Durante las últimas décadas, los operadores de redes móviles han sido testigos de un aumento exponencial en la demanda de tráfico, principalmente debido a la gran solicitud de servicios de una gran cantidad de usuarios. La tendencia es un aumento adicional tanto en la demanda de tráfico como en la cantidad de dispositivos conectados en los próximos años. Se espera que la carga de tráfico tenga una tasa de crecimiento anual del 53% solo para la red móvil, y la próxima era industrial, que conectará diferentes tipos de dispositivos a la infraestructura móvil, definitivamente exacerbará tal aumento. Las instrucciones actuales anticipan que las redes móviles futuras estarán compuestas por despliegues ultra densos de estaciones base (BS) heterogéneas. En consecuencia, la capa tradicional de Macro BS se complementará o reemplazará con múltiples niveles superpuestos de pequeños BS (SBS), lo que permitirá ampliar la capacidad del sistema. Sin embargo, el uso masivo de la Tecnología de la Información y la Comunicación (TIC) y el despliegue denso de los elementos de la red aumentará el nivel de energía consumida por la infraestructura de telecomunicaciones y su huella de carbono en el medio ambiente. Las estimaciones actuales indican que el 10% de la generación mundial de electricidad se debe a la industria de las TIC y se prevé que este valor alcance el 51% para 2030, lo que implica que el 23% de la huella de carbono por actividad humana se deberá a las TIC. La sostenibilidad ambiental es, por lo tanto, un requisito clave para diseñar redes móviles de próxima generación. Recientemente, el uso de fuentes de energía renovables (RES) para suministrar elementos de red ha atraído la atención de la comunidad investigadora, donde el interés se ve impulsado por el aumento de la eficiencia y la reducción de los costos de los recolectores y dispositivos de almacenamiento de energía, especialmente cuando se instalan para suministrar SBS. Se ha demostrado que dicha solución es ambiental y económicamente sostenible tanto en áreas rurales como urbanas. Sin embargo, las RES conllevarán una mayor complejidad de gestión. De hecho, la energía ambiental es inherentemente errática e intermitente, lo que puede causar una entrada de energía fluctuante y producir una interrupción del servicio. Por lo tanto, es necesario un control adecuado de cómo se drena y equilibra la energía entre los elementos de la red para un diseño de red autosostenible. En esta disertación, nos enfocamos en la energía cosechada a través de paneles solares que se considera la más apropiada debido a la buena eficiencia de los paneles fotovoltaicos comerciales, así como a la amplia disponibilidad de la fuente solar para instalaciones típicas. Las características de esta fuente de energía se analizan en la primera parte técnica de la disertación, al considerar un enfoque basado en la extracción de características de los datos recopilados de radiación de energía solar. En la segunda parte técnica de la tesis presentamos nuestro escenario propuesto. Una federación de BS junto con los cosechadores distribuidos y los dispositivos de almacenamiento forman una microrred, cuyas operaciones son administradas por un sistema de administración de energía a cargo de controlar el presupuesto de energía intermitente y errático de las RES. Consideramos el control de carga como un método para administrar adecuadamente la entrada y el gasto de energía, en función de la demanda de tráfico. Además, en la tercera parte técnica, presentamos la posibilidad de mejorar la eficiencia energética de la red al compartir la energía excedente que puede estar disponible en algunos sitios dentro de la microrred. Finalmente, se propone un controlador centralizado basado en aprendizaje supervisado y de refuerzo en la última parte técnica de la disertación. El controlador está a cargo de operar la red para lograr una utilización eficiente de energía y previene el apagón de SBS
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Ernst, Friederike [Verfasser]. "Energy transfer in nanotube-chromophore complexes / Friederike Ernst". Berlin : Freie Universität Berlin, 2013. http://d-nb.info/1043480730/34.
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Wickham-Jones, C. T. "Studies of vibrational energy transfer of small molecules". Thesis, University of Oxford, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.371569.
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Reid, Jonathan Philip. "Vibrational energy transfer in gases at low temperatures". Thesis, University of Oxford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362081.
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Stevens, Amy L. "Energy transfer processes in supramolecular light-harvesting systems". Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:43833f3a-96b0-432a-9608-8f08a9096be7.
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This dissertation attempts to understand how energy transfer in a molecular wire and a spherical organic assembly are affected by molecular structure. The molecular wire is a DNA-hybrid structure composed of a strand of thymine bases appended by a cyanine dye. Hydrogen bonded to each base is a naphthalene-derivative molecule. Using time-integrated photoluminescence and time-correlated single photon counting measurements, energy transfer from the naphthalene donors to the cyanine acceptors was confirmed, and its dependence on temperature and DNA-template length investigated. Donor-thymine bonding was disrupted at temperatures above about 25 degrees Celcius resulting in poor donor template decoration and low rates of energy transfer. Increasing numbers of donors attach to the scaffold, forming an orderly array, as the template length increases due to the stabilising effects of the donor-donor pi-stacking interactions. Conversely, modelled energy transfer rates fall as the scaffold length increases because of the longer donor-acceptor distances involved. Therefore, the energy transfer rate was greatest for a template built from 30 thymines. The spherical organic assemblies (nanoparticles) are formed by fast injection of a small volume of molecularly dissolved fluorene-derivative amphiphilic molecules into a polar solvent. The amphiphilic molecules contained either a naphthalene (donor) or a benzothiadiazole (acceptor) core. The donor-acceptor mixed nanoparticles resemble an amorphous polymer film and were modelled as such using the Foerster resonance energy transfer theory. The Foerster radii extracted from the measurements depends intricately on the donor-acceptor spectral overlap and distance. The latter effect was controlled by the stacking interactions between the molecules. Altering the morphology of the structural units is the key to optimising energy transfer in molecular structures. To achieve efficient organic molecule-based devices, the importance of this property needs to be fully appreciated and effectively exploited.
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Salter, Robert John. "Energy transfer in fundamental kinetic and photolysis processes". Thesis, University of Leeds, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.534839.
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