Dissertations / Theses on the topic 'Photo-Dynamics'
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Kadi, Malin. "Ultrafast Photo-induced Reaction Dynamics of Small Molecules." Doctoral thesis, Uppsala University, Department of Physical Chemistry, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3597.
The main focus of this thesis is the investigation of the dissociation dynamics of aryl halides using femtosecond pump-probe spectroscopy. In the monohalogenated aryl halides, iodo-, bromo- and chlorobenzene, the rate of dissociation following excitation at 266 nm in the gas phase increased with increasing mass of the halogen atom. This process was assigned to predissociation of the initially excited singlet (π, π*) state via a repulsive triplet (n, σ*) state due to spin-orbit interaction. In addition to the predissociative mechanism, a direct dissociation channel was observed in iodobenzene. The rate of the predissociation in bromobenzene was found to be faster in the condensed phase than in the gas phase, which can be explained by solvent-induced symmetry perturbations. Ab initio calculations of the potential energy surfaces of the ground state and several low lying excited states in bromobenzene have been performed in order to verify the suggested mechanism. Substituting one of the hydrogen atoms in bromobenzene affected the predissociation rate significantly. In o-, m- and p-dibromobenzene the predissociation rate increased with decreasing distance between the bromine atoms in accordance with an increased spin-orbit interaction introduced by the bromine substituent. The fastest predissociation rate was observed in 1,3,5-tribromobenzene. With chlorine and fluorine substitution, inductive and conjugative effects were found to be of importance. In the o- and m-isomers of the dihalogenated aryl halides, an additional faster dissociation channel was observed. Guided by ab initio calculations of the potential energy surfaces in the dibromobenzene isomers, we ascribed the fast dissociation pathway to predissociation of an initially excited triplet state. Upon methyl group substitution in bromobenzene, the decreased lifetime of the initially excited state was attributed to an incresaed density of coupled states.
Another system which has been studied in the condensed phase is diiodomethane. Using Car-Parrinello molecular dynamics simulations we observed a prompt dissociation and subsequent recombination to the isomer, iso-diiodomethane, in acetonitrile solution.
Vibrational wavepacket dynamics in the C (1Σ+) state of NaK were studied using a direct ionization probing scheme. A simple analytical expression for the pump-probe signal was developed in order to see what factors that govern direct ionization of the vibrational wavepacket. Our experimental data was consistent with a photoionization transition dipole moment that varies with internuclear distance.
Eitoku, Takeshi. "Photo-induced conformational dynamics of phototropin LOV domains." 京都大学 (Kyoto University), 2008. http://hdl.handle.net/2433/136904.
Han, Alex Chao. "Coherence and control in photo-molecular wave packet dynamics." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/53991.
Science, Faculty of
Physics and Astronomy, Department of
Graduate
Suddick, Emma C. "Nitrogen photo-chemistry and the dynamics of CDOM in aquatic environments." Thesis, University of Aberdeen, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.485377.
Chavez, Cervantes Mariana [Verfasser], and Isabella [Akademischer Betreuer] Gierz. "Photo-Carrier Dynamics and Photo-Induced Melting of Charge Density Waves in Indium Wires / Mariana Chavez Cervantes ; Betreuer: Isabella Gierz." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2020. http://d-nb.info/1212585143/34.
Agathangelou, Damianos. "Anabaena Sensory Rhodopsin : effect of mutations on the ultrafast photo-isomerization dynamics." Thesis, Strasbourg, 2019. http://www.theses.fr/2019STRAE001/document.
ASR, is a photoreceptor protein that binds the protonated Schiff base of retinal in two ground state conformations. The particular protein consists a model system where the effect of the protein environment on the isomerization dynamics of the two isomers can be investigated. In this thesis an extended study on point mutated proteins is presented where the variable is the protein environment. The results show significant differences between the two isomers excited state lifetimes with the shorter or longer lifetimes commented in terms of Sl/S2 electronic mixing. Supplementary, the experimental development of a Transient absorption spectrometer (T.A) and a Two-dimensional electronic spectroscopy setup (2DES) operating in the NIR and UV-Vis spectral range respectively are described. The 2DES spectrometer is based on translating wedges made out of birefringent material producing two collinear phase-locked pulses with sub-I Ofs duration. The interferometric precision on controlling the delay between the two pump pulses allows to perform 2DES measurements on systems absorbing in the 360-430 nm range allowing to resolve the excitation process spectrally
Perveaux, Aurelie. "Study of photo induce process by quantum chemistry and quantum dynamics methods." Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLS144/document.
Over the last decades, progress in experimental techniques combined with theoretical simulations has given access to studying and controlling the photochemical reactivity of large molecular systems with numerous technological applications. 3-hydroxychromone and aminobenzonitrile-like molecules are an example where different fluorescence patterns are observed, depending of the solvent or its substituents. Such properties are crucial in the field of organic materials to understand and design materials with specific optical properties such as fluorescent markers.Our strategy to study the photochemistry reactivity is summarised as follows: * Exploring the potential energy surfaces and optimising specific points with quantum chemistry calculations. In a first stage, these are run at the CASSCF/CASPT2 level of theory with a polarised extended basis set, and the solvent effect is described implicitly with the PCM model. * Generating the full dimension potential energy surfaces as analytical functions of the nuclear coordinates.* Solving the nuclear time-dependent Schrödinger equation for all the degrees of freedom. This is achieved with the multilayer Multi-Configuration Time-Dependent Hartree method (ML-MCTDH)
Burtt, Kelly D. "Computational studies of photo-induces isomerization dynamics in a model molecular motor system." abstract and full text PDF (free order & download UNR users only), 2005. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3209954.
Wall, Simon. "Photo-induced dynamics in complex materials probed with femtosecond x-rays and few cycle optical pulses." Thesis, University of Oxford, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.510258.
Pollum, Marvin. "Applying Fundamental Photochemistry to Drive Drug Development: The Photo-Dynamics and Reactions of Sulfur-Substituted Nucleic Acids." Case Western Reserve University School of Graduate Studies / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=case1481287737895585.
Zhao, Yuan. "Identification and quantification studies on structures, dynamics and mechanism for thermal and photo-degradation products of β-carotene." University of Dayton / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1323736801.
Behrmann, Caryn Ann. "Occurrence and group dynamics of Heaviside’s dolphins (Cephalorhynchus heavisidii) in Table Bay, Western Cape, South Africa." Diss., University of Pretoria, 2011. http://hdl.handle.net/2263/30835.
Dissertation (MSc)--University of Pretoria, 2011.
Zoology and Entomology
Unrestricted
Green, Travis Christopher. "Photo-induced charge carrier dynamics and self-organization in semiconductor and metallic nanocrystals : in between the bulk and individual molecules." Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/30480.
Tomita, Takafumi. "Quantum Many-Body Dynamics of the Bose-Hubbard System with Artificial and Intrinsic Dissipation." Kyoto University, 2019. http://hdl.handle.net/2433/242587.
Heiss, Gregor [Verfasser]. "Single-Molecule Microscopy Study of Nano-Systems: From synthetic photo-switchable nano-devices to the dynamics of naturally occurring transcription factors / Gregor Heiss." München : Verlag Dr. Hut, 2012. http://d-nb.info/102029860X/34.
Barreau, Lou. "Étude de dynamiques de photoionisation résonante à l'aide d'impulsions attosecondes." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS511/document.
In this work, photoionzation of atomic and molecular species in the gas phase is investigated with high-harmonic radiation. In a first part, electronic dynamics in the autoionization process of rare gases in studied with electron interferometry. This method gives access to the spectral phase of the transition to the autoionizing state, and allows there construction of the entire autoionization dynamics. The ultrafast electronic dynamics, as well as the build-up of the celebrated asymmetric Fano profile, are observed experimentally for the first time. In a second part, photoionization of NO molecules in the molecular frame is used as a polarimeter to completeley characterize the polarization state of high-harmonics. In particular, this method can address the challenging disentanglement of the circular and unpolarized components of the light. The experimental results, completed by numerical simulations, allow defining optimal generation conditions of fully circularly-polarized harmonics for advanced studies of ultrafast dichroisms in matte
Masson, Antoine. "Réaction par transfert de charge métal-ligand femtochimie aux temps ultra-courts et spectroscopie de l'état de transition en gouttelette d'hélium." Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00649169.
Heiss, Gregor Johann [Verfasser], and Don [Akademischer Betreuer] Lamb. "Single-molecule microscopy study of nano-systems : From synthetic photo-switchable nano-devices to the dynamics of naturally occurring transcription factors / Gregor Heiss. Betreuer: Don Lamb." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2011. http://d-nb.info/1019479086/34.
O'Connor, Timothy F. III. "Synthesis and Dynamics of Photocatalytic Type-II ZnSe/CdS/Pt Metal-Semiconductor Heteronanostructures." Bowling Green State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1340038781.
Galv?o, Carine Cristina Gon?alves. "Organiza??o social entre as f?meas de Sotalia guianensis (Van B?n?den, 1864) da Ba?a da Ilha Grande, Rio de Janeiro, Brasil." Universidade Federal Rural do Rio de Janeiro, 2015. https://tede.ufrrj.br/jspui/handle/jspui/1341.
Made available in DSpace on 2016-10-25T13:39:22Z (GMT). No. of bitstreams: 1 2015 - Carine Cristina Gon?alves Galv?o.pdf: 2315391 bytes, checksum: 154e1cdd3a9bb2de5fd18d636c4a6543 (MD5) Previous issue date: 2015-02-24
Funda??o Carlos Chagas Filho de Amparo ? Pesquisa do Estado do RJ - FAPERJ
Some animals have extremely complex relationships including the formation of matriarchal societies, alliances and communities, specific long-term relationships, and formation of flexible groups, such as dolphins. Ilha Grande Bay, along with Sepetiba Bay, have the largest population of Sotalia guianensis throughout its distribution, with about 1311 individuals in the first one, and 1043 individuals in the second, where it has been registered groups with up to 450 individuals. This study aimed to analyze the social organization of the mothers of S. guianensis from Ilha Grande Bay. The mothers were considered those dolphins observed at least five times in high proximity of a calf; all its associates were also classified as females and included in the analysis. The analysis of these mothers? social structure was carried out in SOCPROG? software (2.5 version) using a Half Weight Index (HWI). It was performed an analysis of the community division by modularity which indicated that individuals do not form independent clusters. A Monte Carlo permutation test was done and showed the presence of preferred associations among some dyads. Finally, a temporal analysis was performed with the use of mathematical models fitted to the Lagged Association Rate to try to explain how associations behave over time. The social structure of the 25 mothers identified in Ilha Grande Bay seems to be poorly differentiated, forming a large social network with weak associations between dyads, and following a fission-fusion dynamics. There was no statistical difference in the associations between and within classes (mothers X females). This work is a contribution to the understanding of the species? social dynamics, which are still poorly known, and highlights the need for more research in the area.
Alguns animais possuem rela??es extremamente complexas, incluindo forma??o de sociedades matriarcais, alian?as e comunidades, relacionamentos espec?ficos de longa dura??o, e forma??o de grupos flex?veis, como ? o caso dos golfinhos. A Ba?a da Ilha Grande, juntamente com a Ba?a de Sepetiba, possui a maior popula??o de Sotalia guianensis em toda a sua distribui??o, com estimativa de 1311 indiv?duos na primeira, e 1043 indiv?duos na segunda, onde j? foram registrados grupos com at? 450 indiv?duos. Este trabalho teve como objetivo analisar a organiza??o social das m?es de S. guianensis da Ba?a da Ilha Grande. Foram consideradas m?es aqueles golfinhos vistos no m?nimo cinco vezes em forte proximidade de um filhote, e todos os seus associados foram classificados como f?meas e inclu?dos nas an?lises. A an?lise da estrutura social destas m?es foi feito no programa SOCPROG? (vers?o 2.5) atrav?s do ?ndice Half Weight (HWI). Foi feita uma an?lise de divis?o de comunidades por modularidade que indicou que os indiv?duos n?o formam agrega??es independentes. Um teste de permuta??o de Monte Carlo foi realizado e mostrou a presen?a de associa??es preferidas entre algumas duplas. Por fim, uma an?lise temporal foi realizada com a utiliza??o de modelos matem?ticos ajustados ? Lagged Association Rate para tentar explicar como as associa??es se comportam no decorrer do tempo. A estrutura social das 25 m?es identificadas de S. guianensis na Ba?a da Ilha Grande se mostrou pouco diferenciada, formando uma grande rede com fracas associa??es entre duplas, seguindo uma din?mica de fiss?o-fus?o. N?o houve diferen?a estat?stica nas associa??es entre e dentro das classes (m?es X f?meas). Este trabalho ? uma contribui??o para o entendimento das din?micas sociais da esp?cie, que ainda s?o pouco conhecidas, e ressalta a necessidade de mais pesquisas na ?rea.
Fugate, Elizabeth Anne. "Understanding the Role of Lattice Defects and Metal Composition Ratio on the Photochemistry of CuFeO2 toward Solar Energy Conversion." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu157788103637799.
Banks, Aaron M. "The seasonal movements and dynamics of migrating humpback whales off the east coast of Africa." Thesis, University of St Andrews, 2013. http://hdl.handle.net/10023/4109.
Eftekhari, Ali. "Photodynamics of upconversion nanoparticles : a combined investigation at ensemble and single particle levels." Electronic Thesis or Diss., Université de Lille (2022-....), 2022. http://www.theses.fr/2022ULILR086.
The unique photoluminescent properties of upconversion nanoparticles (UCNPs), which emit visible light while being illuminated by near infrared (NIR) radiation, have sparked the interest of researchers worldwide and inspired many bioana¬lytical applications. Their anti-Stokes emission, long luminescence lifetime, narrow and multiple absorption and emission bands, and excellent photostability enable background-free and multiplexed detection in thick biological objects. Emission is controlled by a balance of numerous radiative and non radiative pathways, including energy transfers between sensitizers and activators and quenching effects due to the host matrix and surface. Altogether, these processes account for the highly nonlinear response of the emissions to the excitation power. However, despite numerous studies in this field, rationalizing the dynamics of these energy transfers within these nanoparticles still remains a challenge, albeit it controls their time-dependent luminescence (rise and decay) and their emission yield. The purpose of this thesis is thus to investigate the photo-dynamics taking place in different types of UCNPs in order to disentangle the complex energy pathways driving their emission properties at ensemble and single particle levels.First, ultrasmall UCNPs doped with Ytterbium (Yb, sensitizer) and Thulium (Tm, activator) were considered. These particles, due to their tininess (<3nm), have a reduced number of activators, which allows selecting the number of processes controlling their emission: thanks to a limited probability of activator cross relaxation, the dynamics of the energy redistribution in the activator kinetic network is greatly simplified. A minute examination of these ultrasmall UCNP in solution was thus possible using different irradiation schemes (continuous wave, nanosecond pulse, pulse square, sensitizer-mediated or direct activator excitations). In particular, the α-to-β phase transition occurring during the synthesis procedure could be evidenced by the sudden increase of the 3H4 excited state lifetime. Additionally, we also addressed the influence of Yb concentration and surface coating with a shell on the emission dynamics of the different Tm excited states.To study the emission at the single particle level, we have developed a new confocal microscope based on a millisecond-square pulse NIR excitation and an intensified gated CCD camera in order to measure space- and time-resolved spectra. We discuss here two applications of this new tool: (i) we first investigated the emission properties of Tm- and Er-based core and core-shell UCNPs assemblies. According to the nanometric spatial arrangement of the particles, we could demonstrate that the emission dynamics of single particles, 2D monolayers or 3D aggregates differ in terms of power-dependent emission band ratios and lifetimes. (ii) we examined hybrid systems composed of single UCNPs and perylene-based organic films in terms of emission spectra and lifetimes in order to study the nature of the energy transfers from the UCNP to the dye according to the nature emitter excited state
Caleman, Carl. "Towards Single Molecule Imaging - Understanding Structural Transitions Using Ultrafast X-ray Sources and Computer Simulations." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-7915.
Doherty, William Gerard. "Cold atom production via the photo dissociation of small molecules." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:523f87e0-3f19-4382-941c-74b06023b767.
Albero, Sancho Josep. "Photo-induced charge transfer reactions in quantum dot based solar cells." Doctoral thesis, Universitat Rovira i Virgili, 2012. http://hdl.handle.net/10803/81717.
The fundamental processes of the charge transfer reactions between titania dioxide mesoporous films and quantum dots, in blend films of the semiconductor polymer P3HT and CdSe quantum dots and in complete devices fabricated with the polymer PDPCTBT and CdSe quantum dots in working conditions have been studied in this doctoral thesis. The obtained results allow the fabrication of photovoltaic devices with a deeper and wider knowledge of the recombination processes that limit the device efficiency. Therefore, it is demonstrated the possibility of fabrication of quantum dot based solar cells with efficiencies similar or higher than the organic photovoltaic devices.
Gnodtke, Christian. "Dynamik endlicher Vielteilchen-Systeme in intensiven Röntgenlaserpulsen." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2011. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-67676.
Gnodtke, Christian. "Dynamik endlicher Vielteilchen-Systeme in intensiven Röntgenlaserpulsen." Doctoral thesis, Max-Planck-Institut für Physik komplexer Systeme, 2010. https://tud.qucosa.de/id/qucosa%3A25554.
Gonon, Benjamin. "Simulations quantiques non-adiabatiques d’un photo-interrupteur moléculaire vers un dialogue expérience-théorie." Thesis, Montpellier, 2017. http://www.theses.fr/2017MONTT186/document.
This thesis adresses the study and control of the photo-reactivity of molecular switches, here the photo-isomerisation of spiropyrans. This theoretical work has been achieved in close collaboration with the experimental team PFL within the ICB in Dijon. Non-adiabatic quantum dynamics simulations were carried out so as to reproduce and rationalise the experimental results from time-resolved transient absorption spectroscopy. Such experiments have demonstrated ultra-fast photo-reactivity (~ 100 fs) following excitation by an ultra-short LASER pulse. It is interpreted as an internal conversion mechanism between the first singlet excited eletronic state and the ground state via a conical intersection. The theoretical study used the ring-opening reaction of benzopyran as a model. Developments were made regarding: (1) The exploration of the reaction mechanism and the computation of potential energy surfaces with perturbative, post-CASSCF quantum chemistry methods (XMCQDPT2). This investigation showed that results changed significantly compared to those reported in the literature with lower-level calculations. (2) The generation of a diabatic Hamiltonian based on ab initio XMCQDPT2 data. Owing to the significant anharmonicity in the ground electronic state, we designed a new effective approach, quite different from the previous studies. (3) The production of non-adiabatic quantum dynamics simulations using the MCTDH method. The results thus obtained are in excellent agreement with the experimental ones. Including explicitly the LASER pulse allowed us to reproduce and rationalise the action of pulse shaping on control observed in experiments. The present work thus made possible the succesful implementation of a theoretical/experimental collaboration
Raclot, Damien. "MÉTHODOLOGIE D'EXPLOITATION QUANTITATIVE DES PHOTOGRAPHIES AÉRIENNES D'INONDATION DE PLAINE." Phd thesis, Université Montpellier II - Sciences et Techniques du Languedoc, 2003. http://tel.archives-ouvertes.fr/tel-00003257.
Wallace, Amy. "Dynamics of Stony Coral Assemblages on Patch Reefs of the Upper Florida Reef Tract, Including Biscayne National Park." Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3400.
Woodhouse, Joyce. "Etude d'une protéine fluorescente photo-commutable par cristallographie résolue en temps en utilisant les lasers à électrons libres." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAY026/document.
Reversibly switchable fluorescent proteins (RSFPs) are able to reversibly toggle between a fluorescent on-state and a non-fluorescent off-state under visible light irradiation. This property makes them a suitable marker used in super-resolution microscopy (or nanoscopy). The photo-switching mechanism involves isomerisation of the chromophore and a change of its protonation state. This mechanism has been well studied but remains poorly understood. The structural nature and the sequential order of atomistic events are still under debate. Some of them take place on the ultra-fast time scale and make structural investigation by X-ray crystallography impossible using current synchrotron radiation sources whose temporal resolution they offer is limited. X-ray free electron lasers (XFELs) are a new kind of X-ray source producing femtosecond pulses that allow structural investigation of ultra-fast intermediates during photoswitching. They are also so bright that crystallographic data collection from micro- and nanometer-sized crystals became possible. The bright and short XFEL pulses required a new methodology to be developed, the so-called serial crystallography methodology. This method is now being adapted to synchrotron radiation facilities.Here is presented a time-resolved crystallography study of the reversibly switchable green fluorescent protein 2 (rsEGFP2). A microcrystallization protocol is described allowing the preparation of suitable samples in large amounts for time-resolved serial crystallography experiments. A photoswitching mechanism of rsEGFP2 is proposed based on crystallographic results obtained from data collected at the two XFEL facilities currently fully operational, i.e. the LCLS in the USA and SACLA in Japan. In particular, the structure of two photoswitching intermediates have been determined, one featuring a twisted chromophore in the excited state and the other displaying a protonated cis isomer of the chromophore in the ground state. The structural characterization of rsEGFP2 variants by traditional oscillation crystallography combined with the serendipitous discovery of an alternate chromophore conformation in the off-state during an XFEL experiment provided unique insight into the photophysical behavior of the protein
Abdul, Nour Charles. "Identification de paramètres optiques de structures tissulaires : instrumentation prototype associée : application à la dosimétrie de la thérapie photo-dynamique." Vandoeuvre-les-Nancy, INPL, 1994. http://www.theses.fr/1994INPL006N.
Piguet, Joachim. "Advanced Fluorescence Microscopy to Study Plasma Membrane Protein Dynamics." Doctoral thesis, Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-178147.
QC 20151217
Zhang, Zailan. "Electronic structures, quasi-particle and gap dynamics in copper oxides superconductors using Time and Angle Resolved Photoemission Spectroscopy." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066126/document.
The superconductors of the copper-oxide family have been matter of extensive investigations and are still subject of fierce debates. After 30 years of research, some issues have been settled, whereas others remain controversial. The evolution of the superconducting order parameter with temperature and doping level is an exemplary case. In this thesis, we report a systematic Time resolved Angle Resolved PhotoEmission Spectroscopy (ARPES) study of the optimally doped Bi2Sr2CaCu2O8+δ to explore the possibility that an intense photoexcitation of the superconductor can generate a state with incoherent copper pairs and no superfluid density. The employed experimental methods allow us to measure the dynamics of non-equilibrium electrons and of the superconducting gap, providing complementary information to conventional ARPES and optical measurement. Our time resolved ARPES data of Bi2Sr2CaCu2O8+δ, report a momentum-dependent collapse of the superconducting gap upon photoexcitation. Interestingly, the QP relaxation develops a faster component at the threshold fluence F_pair where the gap has fully collapsed. The comparison between the F_pair and the F_phase extracted by tr-THz suggested the existence a fluence regime when the Cooper pairs have survived, but without holding superfluid current. A second major challenge in the physics of HTSCs is the poor understanding of the normal phase at high temperature. We also present the ARPES study of the near nodal pseudo-gap in La2-xBaxCuO4 (LBCO) to show a possible link with charge modulation (stripes). Our data show that the near nodal gap open below the LTT-LTO transition, which is linked to the formation of such modulations, instead of the one where spin modulations appear. The data show that the band structure of LBCO is affected by a renormalization setting in prior to the 70 meV kink. We were able to correlate this renormalization of the ARPES data to the region where the Cu-O bond-stretching mode soften, both in energy and momentum space
Zhang, Zailan. "Electronic structures, quasi-particle and gap dynamics in copper oxides superconductors using Time and Angle Resolved Photoemission Spectroscopy." Electronic Thesis or Diss., Paris 6, 2017. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2017PA066126.pdf.
The superconductors of the copper-oxide family have been matter of extensive investigations and are still subject of fierce debates. After 30 years of research, some issues have been settled, whereas others remain controversial. The evolution of the superconducting order parameter with temperature and doping level is an exemplary case. In this thesis, we report a systematic Time resolved Angle Resolved PhotoEmission Spectroscopy (ARPES) study of the optimally doped Bi2Sr2CaCu2O8+δ to explore the possibility that an intense photoexcitation of the superconductor can generate a state with incoherent copper pairs and no superfluid density. The employed experimental methods allow us to measure the dynamics of non-equilibrium electrons and of the superconducting gap, providing complementary information to conventional ARPES and optical measurement. Our time resolved ARPES data of Bi2Sr2CaCu2O8+δ, report a momentum-dependent collapse of the superconducting gap upon photoexcitation. Interestingly, the QP relaxation develops a faster component at the threshold fluence F_pair where the gap has fully collapsed. The comparison between the F_pair and the F_phase extracted by tr-THz suggested the existence a fluence regime when the Cooper pairs have survived, but without holding superfluid current. A second major challenge in the physics of HTSCs is the poor understanding of the normal phase at high temperature. We also present the ARPES study of the near nodal pseudo-gap in La2-xBaxCuO4 (LBCO) to show a possible link with charge modulation (stripes). Our data show that the near nodal gap open below the LTT-LTO transition, which is linked to the formation of such modulations, instead of the one where spin modulations appear. The data show that the band structure of LBCO is affected by a renormalization setting in prior to the 70 meV kink. We were able to correlate this renormalization of the ARPES data to the region where the Cu-O bond-stretching mode soften, both in energy and momentum space
Bender, Vitor Cristiano. "Modelagem e acionamento de diodos orgânicos emissores de luz (OLEDs) para sistemas de iluminação." Universidade Federal de Santa Maria, 2015. http://repositorio.ufsm.br/handle/1/3691.
This thesis presents the study and characterization of organic light-emitting diodes (OLEDs) with the proposal of obtaining an equivalent model that is useful in the OLED driver design and in lighting systems projects. Initially, a literature review covering the operating principle and the constructive aspects of OLEDs is presented. From this, a model that integrates scale, photometrical, electrical and thermal aspects is proposed. This model is static and dynamic and is called EFET. A procedure for parameter identification of the model is proposed, jointly with an analysis of the intrinsic capacitance effect on the OLED electrical, thermal and photometrical performance. The proposed model is able to predict and simulate the OLED based lighting systems before building, saving time and cost. The model is validated using different OLED samples and conclusions are derived from the experimental validation and simulation results. An approach considering the dimming methods of OLEDs is presented, showing the chromatic impact caused by each method. Finally, an OLED driver based on the concept of switched capacitor converters is proposed. The thesis results are satisfactory and provide an enhancement to the state of the art in modeling and OLED driving.
A presente tese de doutorado apresenta o estudo e a caracterização de diodos orgânicos emissores de luz (OLEDs) com a proposta de um modelo equivalente que é útil no desenvolvimento de circuitos de acionamento e na análise de OLEDs, quando aplicados em sistemas de iluminação. Inicialmente, é apresentada uma revisão bibliográfica contemplando o princípio de funcionamento e os aspectos construtivos dos OLEDs. A partir disto, um modelo que integra os aspectos de escala, fotométricos, elétricos e térmicos é proposto. Esse modelo é denominado EFET e é dividido em estático e dinâmico. Uma proposta de procedimento para identificação dos parâmetros do modelo é apresentada, juntamente com a análise do efeito da capacitância intrínseca dos OLEDs no seu desempenho elétrico, térmico e fotométrico. Com o modelo proposto pode-se predizer e simular o comportamento dos OLEDs antes de construir o sistema de iluminação, reduzindo custos e tempo de desenvolvimento. O modelo é validado empregando diferentes amostras de OLEDs. Conclusões são obtidas a partir da validação experimental e de simulações empregando simuladores elétricos e da fluidodinâmica computacional através do método de elementos finitos. Uma abordagem considerando os métodos de ajuste da intensidade luminosa de OLEDs é apresentada, evidenciando o impacto cromático provocado por cada método. Por fim, um circuito de acionamento para OLEDs baseado no conceito de capacitores chaveados é proposto. Os resultados obtidos são satisfatórios e proporcionam um incremento ao estado da arte da modelagem e acionamento de OLEDs.
PESTANA, Rayner Carvalho. "Para a implanta??o da meritocracia na gest?o de carreira: implica??es dos contextos cultural, gerencial e pol?tico de uma empresa estatal federal brasileira." Universidade Federal Rural do Rio de Janeiro, 2015. https://tede.ufrrj.br/jspui/handle/jspui/1343.
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The transformation of the Brazilian Public Management, specifically about the adoption of modern tools for human resources, has been happening since the last century and the concern about the introduction of meritocracy in career management is still considered a recurring theme. An evidence of that is the guidance from management and control department of federal state-owned companies to adopt meritocracy in their career management systems. The organization studied here, although already have passed thirteen years of validity of its current jobs and salaries plan, seems not yet to have been able to establish career management policies based on meritocracy. Due to the problem presented, the main objective of this research focused on raising the implications of the organizational context of a Brazilian federal state-owned company, dependent on the Treasury, for the introduction of meritocracy in career management. An applied qualitative research was carried out, configured in the form of a single case study to map the features of the current cultural, managerial and political contexts and to interpret their implications in the adoption of meritocracy as an organizational value. The research subjects were purposefully selected, among managers and career employees, and interviewed based on a script and from a photograph (photo elicitation) to reveal the current context. The field data were subjected to an inductive hermeneutic analysis. Based on these results, it can be inferred that meritocracy in career management, understood as ?a set of criteria, adopted by an organization that has on individual performance, effort and results, the fundamental pillars for granting promotions and progressions to its employees in their own careers?, is not yet explicitly manifested in the studied company. It was perceived that the company is set as a political arena type and that the current alternative process of granting promotions and progressions has been working as a fundamental mechanism for the on going internal power dynamics. On the context found, some manager actions were proposed to contribute to the implementation of meritocracy in career management. It can be considered, as a contribution to the field, the opportunity for reflecting on the negative implications of the penetration of management values in human resources, regarding: uncritical transfer of tools from the private sector to the public one; defense of entrepreneurship discourse that considers the career management as sole responsibility of the professional; only financial and quantitative focus on performance evaluations; and probability of management tools not resulting in professional development but only in the control and exploitation of the individual. For future research it is suggested i.e.: to investigate what commitment means to the organizational members in order to connect it to the company's concepts raised in the study; to analyze meritocracy from the psychological contract breach viewpoint; and to expand this study to other public organizations dependent or not on the Treasury, to ascertain the implications of cultural and managerial traits and the power dynamics for the adoption of meritocracy in career management.
A transforma??o da Administra??o P?blica Brasileira, no que tange ? ado??o de ferramentas modernas de gest?o de pessoas, vem ocorrendo desde o s?culo passado e a preocupa??o com a meritocracia na gest?o de carreira se configura como um assunto ainda recorrente. Como prova disso, destacam-se as orienta??es do ?rg?o de gest?o e controle das empresas estatais federais para que elas adotem a meritocracia nos seus sistemas de gest?o de carreira. A organiza??o aqui estudada, embora passados treze anos de vig?ncia do atual plano de cargos e sal?rios, parece ainda n?o ter conseguido instituir pol?ticas de gest?o de carreira calcadas na meritocracia. Diante do problema apresentado, o objetivo principal desta pesquisa se concentrou em levantar as implica??es dos tra?os provenientes do contexto organizacional de uma estatal federal brasileira, dependente do Tesouro Nacional, para a implanta??o da meritocracia na gest?o de carreira. Realizou-se pesquisa aplicada de natureza qualitativa, configurada em forma de estudo de caso ?nico para mapear os tra?os do contexto cultural, gerencial e pol?tico vigentes e interpretar suas implica??es na ado??o da meritocracia como um valor organizacional. Os sujeitos da pesquisa foram selecionados pelo m?todo proposital, entre gerentes e empregados de carreira, e entrevistados mediante roteiro e a partir de uma fotografia (elicita??o fotogr?fica) que revelasse o contexto vigente na ?tica dos mesmos. Os dados de campo foram qualitativamente analisados de forma hermen?utico-indutiva. Com base nos resultados obtidos, conclui-se que a meritocracia na gest?o de carreira, entendida como ?o conjunto de crit?rios, adotado por uma organiza??o, que possui no desempenho, no esfor?o individual e nos resultados alcan?ados os pilares fundamentais para a concess?o de promo??es e progress?es dos empregados em suas respectivas carreiras?, n?o ?, ainda, praticada explicitamente na empresa estudada. Revelou-se que a empresa se configura como uma organiza??o do tipo arena pol?tica e que o vigente processo alternativo de concess?o de promo??es e progress?es tem funcionado como um mecanismo fundamental na din?mica interna de poder. Diante deste contexto, foram propostas a??es de forma a contribuir com a implanta??o da meritocracia na gest?o de carreira. Considera-se como contribui??o ? ?rea a oportunidade de reflex?o sobre as implica??es da penetra??o de valores do management na gest?o de pessoas, relativas a: transfer?ncia acr?tica de ferramentas do setor privado para o p?blico; defesa do discurso do empreendedorismo, pressupondo a gest?o de carreira como responsabilidade unicamente do profissional; perspectiva apenas financeira e quantitativa das avalia??es de desempenho; e probabilidade das ferramentas de gest?o n?o resultarem no desenvolvimento profissional, mas no controle e explora??o do indiv?duo. Para aprofundamento em futuras pesquisas, sugere-se, dentre outras a??es: investigar o conceito de comprometimento na organiza??o, conectando-o ?s concep??es da Empresa levantadas no estudo; analisar a meritocracia a partir da ?tica da quebra do contrato psicol?gico; e expandir a presente pesquisa a outras organiza??es p?blicas dependentes ou n?o do Tesouro, a fim de evidenciar as implica??es dos tra?os culturais e gerenciais e da din?mica de poder existentes na ado??o da meritocracia na gest?o de carreira.
Bruhat, Laure. "Microwaves as a probe of quantum dot circuits : from Kondo dynamics to mesoscopic quantum electrodynamics." Thesis, Paris Sciences et Lettres (ComUE), 2016. http://www.theses.fr/2016PSLEE012/document.
This thesis uses microwaves as probe of carbon nanotube quantum dot circuits. In a first experiment, a microwave excitation is directly applied to a circuit electrode for a quantum dot in the Kondo regime. We provide the first frequency-amplitude characterisation of the Kondo zero-bias conductance. Preliminary data are consistent with predicted universal behaviour. We present two other experiments, where quantum dot circuits are embedded in microwave resonators. Cavity photons probe charge relaxation resistance and photon-emission in a quantum dot coupled to normal and superconducting reservoirs in presence of Coulomb repulsion. Our observations validate a modelling in terms of the circuit linear response. We also present the first implementation of a Cooper pair splitter in cavity. The strong coupling regime is achieved, a premiere with quantum dot circuits. Our findings support the idea, that mesoscopic quantum electrodynamics is a fruitful toolbox in the context of both fields of quantum transport and quantum information science
Chen, Wei-Hui, and 陳偉暉. "Quantum Molecular Dynamics Analysis on the Performance of Nanotube Photo-Electrochemical Solar Cells." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/60409239216537257675.
Lan, Zhenggang [Verfasser]. "Photo-induced nonadiabatic dynamics of aromatic molecules via conical intersections : electronic-structure and time-dependent quantum dynamics calculations / Zhenggang Lan." 2007. http://d-nb.info/985218819/34.
Chien, Hao-Shen, and 簡豪伸. "Research on the Maintenance Strategy of Reconnaissance Photo-Equipmentfor Military Aircraft Using System Dynamics." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/surwkk.
育達科技大學
資訊管理所
105
Because the purchase of high-tech equipment by the Army is mostly from overseas for a small amount and D-Level repair is usually done by sending back to the foreign original equipment manufacturers, the time for relevant procedures and processes takes too long. Consequently, it is hard to maintain the availability. The purpose of this research aims to study the change of equipment availability, with Photo-Equipment as the subject. The relevant factors would be taken into account including working hours of equipment and the occupational stress derived from image processing. The objective of this research is to explore the dynamic situation of equipment availability under the different situations of maintenance time delay through the analysis of Vensim system dynamic simulation software. Via system dynamic model, however, most research which discussed the Photo-Equipment working hours, maintenance time delay, image process, staff work overload, and the availability of equipment has focused on the static situation. This research, from static perspective to dynamic perspective, could match the reality better and find the proper amount of Photo-Equipment to build suitable maintenance strategies.
Zeman, Matthew Casimir. "In situ, real-time characterization of silicide nanostructure coarsening dynamics by photo-electron emission microscopy." 2007. http://www.lib.ncsu.edu/theses/available/etd-05102007-101442/unrestricted/etd.pdf.
LUO, LI-YANG, and 駱立揚. "Dynamics of Dye Sensitized Solar Cell: the Diffusion Rate of Photo-electrons in TiO₂ Nanotube." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/zyaky9.
朝陽科技大學
應用化學系
106
For studying the charge transfer process of array titanium oxide’s(ATO) microstructure, we measured measured the photovoltaic parameters with IV, IPCE, transient photocurrent and photovoltage under various TiO₂ tube length. In addition, the effects of dyeloading and thickness of electrolyte of ATO were also investigated. The diffusion rate and electron lifetimes are almost the same under similar length of TiO₂ tube. The molecular dyeloading desnity on TiO₂ surface influences the open-circuit voltage and electron lifetime, but the dyeloading does not influence the electron diffusion rate. When we modified the thickness of electrolyte, the thickness of electrolyte alters the distribution of density of trapped states and the potential of band edge on TiO₂. However, the thickness of electrolyte does not affect the diffusion rate. According to the prior results, the dyeloading and thickness of electrolyte don’t influence the electron diffusion rate. It is important to realize the dependance of diffusion rate and length of TiO₂ tube when the thick TiO₂ film generates the higher current density. The diffusion rate becomes faster on the longer TiO₂ tube under the same current density.
Burmeister, Carl Friedrich. "Primary Effects of X-ray and Photo-Absorption Induced Excitations in Biomolecules." Doctoral thesis, 2013. http://hdl.handle.net/11858/00-1735-0000-0001-B984-D.
Huang, Chang-tai, and 黃章泰. "Resolving the dynamics of photo-induced phase transition of eumelanin by femtosecond pump-probe techniques using whitelight-generation probe pulse." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/23612475179636422570.
國立中正大學
物理所
97
Eumelanin is one of the most ubiquitous biological pigments found in human body. Despite many decades of studies, people still do not have a complete picture of its macromolecular structure. Since eumelanin has a well-known, broad-band monotonic absorption, studying the dynamics of light absorption becomes an important method to investigate the structure of eumelanin. From the degenerate UV pump-probe experiment by Simon et al., the optical absorption spectrum of the monomer and tetramer composing of four monomers found to be quite different is quite different. We use the whitelight-generation pulse as probe beam to perform the femtosecond pump-probe experiment to explore the structure dynamics of eumelanin. In chapter 1, we introduce the structure of eumelanin and review the related experiment in the past. In chapter 2, we describe the laser system, the experimental setup and parameters used in the experiment. In charpter 3, we show the experiment results and propose an appropriate model to explain the data. The last chapter is the conclusion of this study and possible follow-up works.
Ronge, Emanuel. "In-Situ Environmental TEM Studies of Electro- and Photo-Electrochemical Systems for Water Splitting." Doctoral thesis, 2020. http://hdl.handle.net/21.11130/00-1735-0000-0005-157D-8.
Praneeth, N. V. S. "Development of Gold and Gold/semiconductor Nanostructures for Plasmonic and Photo/Electro-Catalytic Applications." Thesis, 2021. http://ethesis.nitrkl.ac.in/10368/1/2022_PhD_N.V.S.Praneeth_512CH1009_Development.pdf.
"Soot Black Carbon Dynamics in Arid/urban Ecosystems." Doctoral diss., 2013. http://hdl.handle.net/2286/R.I.20912.
Dissertation/Thesis
Ph.D. Chemistry 2013