Дисертації з теми "Structure and dynamics of materials"
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Hampson, Matthew Richard. "Structure and dynamics in framework materials." Thesis, Durham University, 2007. http://etheses.dur.ac.uk/1999/.
Повний текст джерелаRoeder, H. "Defects and dynamics of modulated structure materials." Thesis, University of Oxford, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375323.
Повний текст джерелаDong, Jingwei. "Electron dynamics in layered materials." Thesis, Institut polytechnique de Paris, 2021. http://www.theses.fr/2021IPPAX019.
Повний текст джерелаCurrently,layered materials attract great interest due to their electrical and optical properties. Such crystals display an electronic band structure that strongly depends on the sample thickness.The large tunability of the electronic screening and gap size can be very attracting for the creation of heterostructures whose properties can be designed on demand. We can say that the research field of low dimensional materials has been boosted by the discovery of graphene and quickly has been enlarged to other materials as transition metal dichalcogenides,black phosphorous and Indium selenide.Our work will focus on the excited state dynamics in these compounds,as well as on the evolution of the band structure upon surface doping.The manuscript is organized as follow:Chapter1 provides a general introduction of layered materials.In particular,we discuss the structural and electronic properties of some relevant compounds.Chapter2 describes the principles of ultrafast spectroscopic methods and shows many applications to the case of the layered materials.We mainly focus our attention on the electron dynamics in semiconducting crystals and charge density waves systems. The electron dynamics of layered materials have been investigated by means of time-and angle-resolved photoelectron spectroscopy (TrARPES),which is a powerful tool to directly map the electronic band structure and to follow the dynamics of the electrons photoinjected via an ultrafast laser source.Chapter3 discusses the experimental technique of choice and the setup where we have been performed in the reported measurements.we begin the discussion of our original data in Chapter4.The TrARPES measurements of layered black phosphorus(BP) monitor the electronic distribution in the conduction and valence band as a function of delay time from photoexcitation.The data show that,after thermalization,the photo-injected electrons do not lead to sizable band gap renormalization,neither do they generate an appreciable amount of carrier multiplication.On the other hand,a Stark broadening of the valence band is ascribed to the inhomogeneous screening of a local potential around charge defects.Chapter5 shows time resolved ARPES data on a BP surface that is doped in-situ by means of alkali metals evaporation. We monitor the collapse of the band-gap in the accumulation layer with unmatched accuracy and we observe that the buried states detected by the low energy photons of our probing pulse acquire a surprisingly high band velocity at large dopants concentration.Chapter6 deals with the modification of hot carrier dynamics upon increasing the surface doping of BP.In this case the reported analysis is still preliminary and needs to be backed by ab-initio calculations.Chapter7 contains our work on layered ɛ-InSe.As in the case of BP,we generate an accumulation layer of varying electronic density on the surface of such semiconductor.By spanning the doping level from the semiconducting to the metallic limit,we observe that quantum screening of Longitudinal Optical phonons is not as efficient as it would be in a strictly bidimensional system,indicating a remote coupling of confined states to polar phonons of the bulk.Furthermore,we show that a 3D Fröhlich interaction with Thomas-Fermi screening can be used to mimic the effects of such a remote coupling at the ɛ-InSe surface.In Chapter8,we study the layered 1T-TaS2.This material belongs to the Charge density waves (CDW) systems and has been extensively investigated by several research groups.In 1T-TaS2,the combination of structural distortion with high electronic correlations leads to a complex and fascinating phase diagram.We could reproduce controversial data that have been recently published in the literature and that identify a new instability in proximity of the metal to-insulator transition.Finally,chapter9 summarizes the conclusions of our work and briefly discusses the perspectives of some future directions of research
Sridhar, Yerusu R. "Molecular Dynamics Simulations of Organic Photovoltaic Materials: Structure and Dynamics of Oligothiophene/Fullerene Blends." University of Cincinnati / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1342545038.
Повний текст джерелаSun, Liang. "Structure and Dynamics of Swollen Polymer Brushes." University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1499675793233755.
Повний текст джерелаNicholson, Christopher W. [Verfasser]. "Electronic Structure and Dynamics of Quasi-One Dimensional Materials / Christopher W. Nicholson." Berlin : Freie Universität Berlin, 2018. http://d-nb.info/117122284X/34.
Повний текст джерелаChen, Ying. "NMR Applications in Soft Materials Science: Correlation of Structure, Dynamics, and Transport." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/75177.
Повний текст джерелаPh. D.
Wiper, Paul Vincent. "Novel sol-gel materials for advanced glass products : structure, dynamics and stability." Thesis, University of Liverpool, 2012. http://livrepository.liverpool.ac.uk/7993/.
Повний текст джерелаVachhani, Neal Arvind 1981. "Using narrowband pulse-shaping to characterize polymer structure and dynamics : Deathstar GHz spectroscopy." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/27876.
Повний текст джерелаThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (leaves 117-122).
(cont.) The validation of this technique for probing amorphous polymer structure and dynamics lays the ground for further study of heterogeneous materials, such as nanocomposites and block copolymers.
A narrowband pulse-shaper called the Deathstar has been used along with a picosecond acoustic technique to study amorphous polymers. The temperature dependence of the longitudinal acoustic velocity and the frequency dependence of the acoustic attenuation have been measured. The frequency range of longitudinal phonons studied is not directly accessible by other spectroscopies. Probing material response in this intermediate regime is valuable because it helps characterize secondary transitions and energy dissipation mechanisms in polymers. Broadband experiments have been done to study the temperature dependence of the acoustic velocity for polystyrene and poly(methyl methacrylate) from 10 K to 300 K. The results are in line with literature values and the predictions of a model based on acoustic impedance mismatch theory. Narrowband studies with the technique used were previously limited to amorphous silica. They are extended for the first time to amorphous polymers. The Deathstar GHz spectroscopy is used to determine the absolute acoustic attenuation coefficient as a function of frequency for PMMA. The values obtained are similar to those found in literature. However, the method used to measured attenuation here is more reliable. The frequency at which attenuation has been measured ranges from 55 GHz to 160 GHz. To explore additional dynamics, attenuation is also measured at temperatures above and below the polymer glass transition. The details of the experimental technique are discussed, and the results are presented.
by Neal Arvind Vachhani.
S.M.
Dean, Nicky. "Electronic and structural dynamics of complex materials." Thesis, University of Oxford, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.543469.
Повний текст джерелаMaraytta, Nour Abdalmajeed Verfasser], Thomas [Akademischer Betreuer] [Brückel, and Georg [Akademischer Betreuer] Roth. "Structure and dynamics of magnetocaloric materials / Nour Abdalmajeed Maraytta ; Thomas Brückel, Georg Roth." Aachen : Universitätsbibliothek der RWTH Aachen, 2021. http://d-nb.info/123814957X/34.
Повний текст джерелаAeberhard, Philippe C. "Computational modelling of structure and dynamics in lightweight hydrides." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:bfaf28b1-da03-4ce9-8577-5e8c18eb05ae.
Повний текст джерелаYimer, Yeneneh Yalew. "Molecular Ordering, Structure and Dynamics of Conjugated Polymers at Interfaces: Multiscale Molecular Dynamics Simulations." University of Akron / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1416796729.
Повний текст джерелаHASHMI, QUAZI SARWAR EHSAN. "NONASSOCIATIVE PLASTICITY MODEL FOR COHESIONLESS MATERIALS AND ITS IMPLEMENTATION IN SOIL-STRUCTURE INTERACTION." Diss., The University of Arizona, 1987. http://hdl.handle.net/10150/184024.
Повний текст джерелаGong, Chuncheng. "Atomic structure and dynamics study of defects in graphene by aberration-corrected transmission electron microscope." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:53bd9a04-71ad-4da8-b982-cb45a005e791.
Повний текст джерелаGardner, Adam R. "Molecular dynamics of aot/water/isooctane reverse micelles dynamic and structural analysis and effect of zirconium ions on the micelles structure for ZrO2 nanoparticle production /." abstract and full text PDF (free order & download UNR users only), 2007. 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:1442844.
Повний текст джерелаCarsí, Rosique Marta. "Molecular mobility. Structure-property relationship of polymeric materials." Doctoral thesis, Universitat Politècnica de València, 2016. http://hdl.handle.net/10251/59460.
Повний текст джерела[ES] En este trabajo se presenta un estudio de la influencia de la estructura química de los polímeros en su comportamiento térmico, mecánico y dieléctrico. Las técnicas experimentales empleadas para ello han sido la calorimetría diferencial de barrido, el análisis dinamo-mecánico y la espectroscopia dieléctrica. Adicionalmente, se han empleado otras técnicas como la difracción de rayos, con objeto de corroborar los resultados obtenidos por las primeras. En los Capítulos 1 y 2 se recoge la introducción y los objetivos, respectivamente. El Capítulo 3 presenta una breve descripción de las técnicas experimentales empleadas. En el Capítulo 4 se recogen los resultados obtenidos en el análisis comparativo de la respuesta a campos de perturbación eléctrica en un amplio rango de frecuencias y temperaturas para tres polimetacrilatos de bencilo con dos grupos dimetoxi en posiciones 2,5-, 2,3- y 3,4-. Los resultados obtenidos señalan el importante efecto de la posición de los grupos dimetoxi en el anillo aromático, sobre la dinámica molecular del polimetacrilato de bencilo. Los espectros obtenidos fueron muy complejos, por ello en orden a llevar a cabo un mejor análisis se emplearon métodos numéricos para la transformación tiempo-frecuencia que incluyeron el uso de técnicas de regularización paramétrica. Se ha estudiado el efecto que dicho cambio estructural ejerce tanto sobre los procesos de relajación secundaria como sobre el proceso de relajación α, relacionado con la transición vítrea. Así mismo, se ha analizado el efecto de la posición de los grupos dimetoxi en la formación de iii nanodominios en los que predominan las cadenas laterales, y su efecto en los procesos de conducción de los materiales analizados. En el Capítulo 5 se recoge el estudio de la conductividad de líquidos gomosos tomando como modelo el poli (metacrilato de 2,3-dimetoxibencilo), por su peculiar comportamiento. En este capítulo se ha realizado un análisis del principio de superposición tiempo-temperatura, empleando para ello diferentes variables relacionadas entre sí. En el Capítulo 6 se recoge el efecto de la presencia de entrecruzante en la movilidad molecular de polimetacrilatos que contienen residuos de éteres de alcoholes alifáticos. En este caso, se ha analizado el efecto de la presencia de entrecruzante tanto en los procesos de relajación secundarios, como en el proceso de relajación principal. También se llevó a cabo un análisis del efecto que la presencia de entrecruzante tiene sobre la creación de nanodominios gobernados por las cadenas laterales.
[CAT] En aquest treball es presenta un estudi de la influència de l'estructura química dels polímers en el seu comportament tèrmic, mecànic i dielèctric. Les tècniques experimentals utilitzades han sigut la calorimetria diferencial de rastreig, l'anàlisi dinamo-mecànic i l'espectroscòpia dielèctrica. Addicionalment, s'han empleat altres tècniques com la difracció de rajos X a fi de corroborar els resultats obtinguts per les primeres. En els Capítols 1 i 2 s'arreplega la introducció i els objectius, respectivament. Al Capítol 3 es presenta una breu descripció de les tècniques experimentals emprades. En el Capítol 4 es recull els resultats obtinguts en l'anàlisi comparativa de la resposta a camps de pertorbació elèctrica en un ampli rang de freqüències i temperatures de tres polimetacrilats de benzil amb dos grups metoxi en posicions 2,5-, 2,3- i 3,4-. Els resultats obtinguts assenyalen l'important efecte de la posició dels grups metoxi en l'anell aromàtic, sobre la dinàmica molecular del polimetacrilat de benzil. Els espectres obtinguts van ser molt complexos, per aquesta raó per a dur a terme un millor anàlisi es van emprar mètodes numèrics per a la transformació temps-freqüència que van incloure l'ús de tècniques de regularització paramètrica. S'ha estudiat l'efecte que el dit canvi estructural exerceix tant sobre els processos de relaxació secundària com sobre el procés de relaxació , relacionat amb la transició vítria. Així mateix, s'ha analitzat l'efecte de la posició dels grups metoxi en la formació de nanodominis en els que predominen les cadenes laterals, i el seu efecte en els processos de conducció dels materials analitzats. En el Capítol 5 s'arreplega l'estudi de la conductivitat de líquids gomosos prenent com a model el poli-(metacrilat de 2,3-dimetoxibencilo), pel seu peculiar comportament. En aquest capítol s'ha realitzat un anàlisi del principi de superposició temps-temperatura, emprant per a això diferents variables relacionades entre sí. En el Capítol 6 s'arreplega l'efecte de la presència d'entrecreuat en la mobilitat molecular de polimetacrilats que contenen residus d'èters d'alcohols alifàtics. En aquest cas, s'ha analitzat l'efecte de la presència d'entrecreuat tant en els processos de relaxació secundaris, com en el procés de relaxació principal. També es va dur a terme un anàlisi de l'efecte que la presència d'entrecreuat químic té sobre la creació de nanodominis governats per les cadenes laterals.
Carsí Rosique, M. (2015). Molecular mobility. Structure-property relationship of polymeric materials [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/59460
TESIS
Premiado
Ali, Fatmah Abdullah Haider. "Examination of atomic scale structure and dynamics of amorphous materials by solid state NMR." Thesis, University of Kent, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.481489.
Повний текст джерелаDewan, Leslie. "Molecular dynamics simulation and topological analysis of the network structure of actinide-bearing materials." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/86266.
Повний текст джерелаCataloged from PDF version of thesis.
Includes bibliographical references.
Actinide waste production and storage is a complex problem, and a whole-cycle approach to actinide management is necessary to minimize the total volume of waste. In this dissertation, I examine three actinide-bearing materials relevant to both the front end and back end of the nuclear fuel cycle: light water reactor (LWR) spent fuel stored in a crystalline ceramic medium (zircon), LWR spent fuel stored in a glassy medium (alkali borosilicate glass), and three molten salt systems (LiF-BeF2, LiF-ThF4 , and LiF-UF4). I model these materials using molecular dynamics (MD) simulations, and then perform a range of material-dependent analyses - including structural evaluation, species segregation, solubility limits, and assessment of transport properties - to examine their suitability as actinide-bearing materials. The initial portion of this work focuses on actinide waste storage media, examining the microstructural changes induced in zircon and alkali borosilicate glass doped with uranium. Alpha-decay of the uranium changes the structure of the host material, inducing amorphousness, recrystallization, and microcracking, among other structural changes. My work on actinide waste storage shows the utility of topological methods for quantifying the intermediate-range structure of amorphous systems. In many cases, the intermediate-range structure correlates with larger-scale properties, such as density and viscosity. I then identify three molten salt systems of interest - LiF-BeF2 , LiF-ThF4, and LiUF4 - as a focus for analysis. LiF-BeF2 is a coolant salt, and LiF-ThF4 and LiF-UF4 are fuel salts used on the front end of the nuclear fuel cycle in molten salt reactors (MSRs). MSRs can, in some configurations, achieve extremely high actinide bum-ups. Some molten salt reactors can also be fueled by the actinides in spent fuel produced by LWRs. While MSRs have many advantages, research into new designs often proceeds slowly because of gaps in available experimental data for the molten fuel and coolant salts. I use MD simulations to evaluate the transport properties and structure of these salts, and show that these simulations can be used reliably to augment the existing body of experimental data describing the salts' material properties. Furthermore, I examine how the structure of the salt correlates with its material properties, in particular its viscosity. I use network topology-based algorithms to describe the amorphous structure quantitatively. Network-based topological methods have never before been applied to molten salts, and many new insights can be gained from the analysis.
by Leslie Dewan.
Ph. D.
Graça, Araújo Carlos Moysés. "Hydrogen Storage Materials : Design, Catalysis, Thermodynamics, Structure and Optics." Doctoral thesis, Uppsala universitet, Institutionen för fysik och materialvetenskap, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-8574.
Повний текст джерелаHubartt, Bradley C. "Nucleation and Growth, Defect Structure, and Dynamical Behavior of Nanostructured Materials." University of Toledo / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1416828345.
Повний текст джерелаPetri, Ingrid. "An investigation of the structure of disordered materials by using neutron diffraction." Thesis, University of Bath, 1999. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299847.
Повний текст джерелаHussain, Tanveer. "Computational Insights on Functional Materials for Clean Energy Storage : Modeling, Structure and Thermodynamics." Doctoral thesis, Uppsala universitet, Institutionen för fysik och astronomi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-206938.
Повний текст джерела李德利 and Deli Li. "Thermodynamic formulation for damaging materials." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1993. http://hub.hku.hk/bib/B31233764.
Повний текст джерелаLi, Deli. "Thermodynamic formulation for damaging materials /." [Hong Kong : University of Hong Kong], 1993. http://sunzi.lib.hku.hk/hkuto/record.jsp?B1367173X.
Повний текст джерелаLee, Min-I. "Atomic structure, electronic states and relaxation dynamics in photovoltaic materials and interfaces from photoemission-related spectroscopies." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS220/document.
Повний текст джерелаThe efficiency of the photovoltaic process depends on the electronic band structure of the active material and the charge carrier dynamics. In this thesis, we have studied how these issues are related to the atomic structure in materials for two different technologies of solar cells, namely silicon heterostructure solar cells, and hybrid organic-inorganic perovskite solar cells. In silicon heterostructure solar cells, we have analyzed the impact of defects on the electronic properties of amorphous silicon heterostructures (a-Si:H/a-SIC:H/c-Si) by core level and valence band spectroscopies. In particular, we have quantified the number of dangling bonds inside a-Si:H layer upon irradiation, we have identified the electronic states associated to them, and we have understood the transitions previously observed by photoluminescence. In perovskite solar cells, we have correlated the atomic structure, the electronic structure and the electronic dynamics for two- and three-dimensional hybrid organic-inorganic perovskites. We have used with this goal a whole panel of complementary techniques: X-ray diffraction, angle-resolved photoemission spectroscopy, inverse photoemission spectroscopy, and time-resolved two-photon photoemission. In the two-dimensional perovskite (C₆H₅C₂H₄NH₃)₂PbI₄, the valence and conduction bands have been determined experimentally and compared to spectral function simulations. In the three-dimensional perovskite CH₃NH₃PbI₃, we have again determined the band structure and simulated it. Very broad spectral features have been experimentally observed, which relax the optical transition conditions impacting in the solarcell efficiencies. In both experiments and calculations, we observe that the spectral weight follows a cubic periodicity while the system is structurally in the tetragonal phase. This apparent contradiction is explained by the band broadness, which hides the band folding of the tetragonal distortion. As for the relaxation dynamics, we have observed that the photoexcited carriers thermalize in a subpicosecond time scale through the coupling to organic cation vibrations. At longer timescales (10~100 picoseconds), the electron diffusion controls the dynamics. This dynamics is affected by the annealing-induced defects, which localize the photoexcited electrons for more than 300 picoseconds
Cadien, Adam. "The Structure and Dynamics of Monatomic Liquid Polymorphs; Case Studies in Cerium and Germanium." Thesis, George Mason University, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=3706976.
Повний текст джерелаThe study of liquid polymorphism is at the frontier of fundamental thermodynamics and materials science. Liquid polymorphism occurs when a single material has multiple structurally unique liquid phases. Water was the first substance suggested to exhibit multiple liquid phases, a number of monatomic semiconductors and metals have been found to exhibit similar characteristics since then. A better understanding of the liquid-liquid phase transition is needed to tackle problems in glass sciences, it is also relevant to geophysical studies of the Earth's core and mantle and has applications in nanotechnology.
Computational methods are critical to developing a better understanding of liquids. Through simulation thermodynamic obstacles that hamper experiments can be artificially bypassed, metastable regions outside the equilibrium phase diagram can be accessed and all of the properties of the system are directly recorded. Computationally it is much simpler to iterate over a range of environmental variables such as temperature, pressure and composition, and measure a system's response. In this thesis ab-initio and semi-empirical approximations are used to accurately describe the complex many body interactions that take place in liquids.
Two independent case studies of liquid polymorphism are presented here. The first is a stable liquid-liquid phase transition was found to occur in Cerium which was initially discovered through X-Ray diffraction experiments and later confirmed through simulation. This phase transition is predicted to end at a critical point.
The second is a comprehensive study of the structure and dynamics of Germanium's many metastable amorphous and liquid phases. This is currently the largest ab-initio based study of the dynamics of Germanium's metastable liquid phases. Methods ranging from the mean square displacement to the van Hove function and intermediate scattering function are introduced and analyzed. The micro-structural characteristics are quantified and correlated with the mobility in the material revealing dynamical heterogeneity.
Riegner, David C. "Molecular Dynamics Simulations of Metallic Glass Formation and Structure." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1471860872.
Повний текст джерелаZhang, Hanyu. "ANALYZING THE SHORT-RANGE ORDER OF METALLIC GLASS THROUGH X-RAY ABSORPTION FINE STRUCTURE (XAFS) SPECTROSCOPY." Case Western Reserve University School of Graduate Studies / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=case1554911796709215.
Повний текст джерелаLi, Lan. "Molecular dynamics simulations of the deformation of nano-structured materials." Diss., Restricted to subscribing institutions, 2007. http://proquest.umi.com/pqdweb?did=1324388961&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
Повний текст джерелаSchnadt, Joachim. "Studies of Model Nanostructured Materials : Geometric and Electronic Structure, and sub-10 fs Charge Transfer Dynamics." Doctoral thesis, Uppsala University, Department of Physics, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-2636.
Повний текст джерелаA number of nanostructured systems has been investigated by means of Photoemission and X-ray absorption spectroscopies and by Scanning tunneling microscopy with emphasis on the geometric and electronic structure and the excited-state charge transfer dynamics. These systems comprise aromatic molecules on semiconductor surfaces (titanium dioxide), metal clusters, and an alkali-C60 compound.
Electronic and geometric structure are complementary to each other, and changes in the geometric structure are accompanied by changes in the electronic structure. Therefore, a detailed investigation of the latter makes it possible to draw conclusions on the former. In particular, this close relationship has been used to characterise the adsorbate geometry of the pyridine-carboxylic acid monomers on rutile TiO2(110), which is determined by the strong substrate bond as well as interadsorbate interactions. Similarly, it has been found that bi-isonicotinic acid adsorbs on a nanostructured anatase TiO2 film by forming strong bonds between both carboxylic groups and the substrate titanium atoms. For deposited metal clusters, the core binding energies are found to mirror the cluster size.
Resonant core electron spectroscopies have been employed to elucidate the excited-state charge transfer dynamics with respect to the transfer of an excited electron from the bi-isonicotinic acid and isonicotinic acid adsorbates to a titanium dioxide semiconductor surface. An important aspect has been the development of new variations of the method in order to be able to unravel the spectra of these relatively complex systems. While a strong excitonic effect localises the excited electron on the adsorbate for the lowest excited state, excitation to the higher excited states leads to an ultrarapid charge transfer on a low- to sub-femtosecond timescale.
In LiC60 the character of the alkali-C60 bond has been investigated. The balance between the different energy contributions points to an ionic bond with an important element of covalency.
Maalouf, Manale W. "Structure and Dynamics Influencing Proton Transport in Materials for High Temperature (120 °C) PEM Fuel Cells." Case Western Reserve University School of Graduate Studies / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=case1311010188.
Повний текст джерелаGowers, Richard. "Developing dual-scale models for structured liquids and polymeric materials." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/developing-dualscale-models-for-structured-liquids-and-polymeric-materials(edfe6991-79de-45a9-84e4-9e9dfb68faa4).html.
Повний текст джерелаHamilton, Myles. "The structure and dynamics of liquid semiconductors and superionic conductors by neutron scattering." Thesis, University of Bristol, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311368.
Повний текст джерелаDelandar, Arash Hosseinzadeh. "Modeling defect structure evolution in spent nuclear fuel container materials." Doctoral thesis, KTH, Materialteknologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-206175.
Повний текст джерелаQC 20170428
Xu, Tao. "The structure-property relation in nanocrystalline materials: a computational study on nanocrystalline copper by Monte Carlo and molecular dynamics simulations." Diss., Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/37108.
Повний текст джерелаLocht, Inka L. M. "Theoretical methods for the electronic structure and magnetism of strongly correlated materials." Doctoral thesis, Uppsala universitet, Materialteori, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-308699.
Повний текст джерелаDing, Ding-Kuo. "Structures and dynamics of disclinations and inversion walls in nematic polymers." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/33510.
Повний текст джерелаShakhov, Alexander. "Structure-Dynamics Relationships in Complex Fluids and Disordered Porous Solids Assessed using NMR." Doctoral thesis, Universitätsbibliothek Leipzig, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-153105.
Повний текст джерелаLencer, Alexander Dominic André [Verfasser]. "Design rules, local structure and lattice-dynamics of phase-change materials for data storage applications / Alexander Dominic Andre Lencer." Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2010. http://d-nb.info/101515025X/34.
Повний текст джерелаSelli, Daniele. "Structure Property and Prediction of Novel Materials using Advanced Molecular Dynamics Techniques: Novel Carbons, Germaniums and High-Performance Thermoelectrics." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-150244.
Повний текст джерелаO'Sullivan, Eoin. "Electronic states and dynamics in semiconductor structures." Thesis, University of Oxford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325987.
Повний текст джерелаBlomqvist, Andreas. "Insights into Materials Properties from Ab Initio Theory : Diffusion, Adsorption, Catalysis & Structure." Doctoral thesis, Uppsala universitet, Materialteori, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-131331.
Повний текст джерелаFelaktigt tryckt som Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 702
Zhang, Xiaowei. "Conceptual study of adaptive energy absorbers /." View abstract or full-text, 2009. http://library.ust.hk/cgi/db/thesis.pl?MECH%202009%20ZHANG.
Повний текст джерелаLam, Stephen Tsz Tang. "Accelerated atomistic prediction of structure, dynamics and material properties in molten salts." Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/129108.
Повний текст джерелаCataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 122-142).
Various advanced nuclear reactors including fluoride high-temperature salt-cooled reactors (FHRs), molten salt reactors (MSRs) and fusion devices have proposed to use molten salt coolants. However, there remain many uncertainties in the chemistry, dynamics and physicochemical properties of many salts, especially over the course of reactor operation, where impurities are introduced, and compositional and thermodynamic changes occur. Density functional theory (DFT) and ab initio molecular dynamics (AIMD) were used for property, structure and chemistry predictions for a variety of salts including LiF, KF, NaF, BeF2, LiCl, KCl, NaCl, prototypical Flibe (66.6%LiF-33.3%BeF2), and Flinak (46.5%LiF-11.5NaF-42%KF). Predictions include thermophysical and transport properties such as bulk density, thermal expansion coefficient, bulk modulus, and diffusivity, which were compared to available experimental data.
DFT consistently overpredicted bulk density by about 7%, while all other properties generally agreed with experiments within experimental and numerical uncertainties. Local structure was found to be well predicted where pair distribution functions showed similar first peak distances (+ 0.1 A) and first shell coordination numbers (+ 0.4 on average), indicating accurate simulation of chemical structures and atomic distances. Diffusivity was also generally well predicted within experimental uncertainty (+20%). Validated DFT and AIMD methods were applied to study tritium in prototypical salts since it is an important corrosive and diffusive impurity found in salt reactors. It was found that tritium species diffusivity depended on its speciation (TF vs. T2), which was related to chemical structures formed in Flibe and Flinak salts. Further, predictions allowed comparison with and interpretation of past contradictory experimental results found in the literature.
Lastly, robust neural network interatomic potentials (NNIPs) were developed for LiF and Flibe. The LiF NNIP accurately reproduced DFT calculations for pair interactions, solid LiF and liquid molten salt. The Flibe NNIP was developed for molten salt at the reactor operating temperature of 973K and was found to reproduce local structures calculated from DFT and showed good stability and accuracy during extended MD simulation. Ab initio methods and NNIPs can play a major role in advanced reactor development. Combined with experiments, these methods can greatly improve fundamental understanding and accelerate materials discovery, design and selection.
by Stephen Tsz Tang Lam.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Nuclear Science and Engineering
Gonçalves, Marques Mário Rui [Verfasser], Miguel [Gutachter] Marques, Wolfgang [Gutachter] Paul, and Patrick [Gutachter] Rinke. "The structure and dynamics of materials using machine learning / Mário Rui Gonçalves Marques ; Gutachter: Miguel Marques, Wolfgang Paul, Patrick Rinke." Halle (Saale) : Universitäts- und Landesbibliothek Sachsen-Anhalt, 2020. http://d-nb.info/1212434870/34.
Повний текст джерелаCurtarolo, Stefano 1969. "Coarse-graining and data mining approaches to the prediction of structures and their dynamics." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/17034.
Повний текст джерелаIncludes bibliographical references (p. 245-263).
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Predicting macroscopic properties of materials starting from an atomistic or electronic level description can be a formidable task due to the many orders of magnitude in length and time scales that need to be spanned. A characteristic of successful approaches to this problem is the systematic coarse-graining of less relevant degrees of freedom in order to obtain Hamiltonians that span larger length and time scale. Attempts to do this in the static regime (i.e. zero temperature) have already been developed, as well as thermodynamical models where all the internal degrees of freedom are removed. In this thesis, we present an approach that leads to a dynamics for thermodynamic-coarse-grained models. This allows us to obtain temperature-dependent and transport properties. The renormalization group theory is used to create new local potential models between nodes, within the approximation of local thermodynamical equilibrium. Assuming that these potentials give an averaged description of node dynamics, we calculate thermal and mechanical properties. If this method can be sufficiently generalized it may form the basis of a Multiscale Molecular Dynamics method with time and spatial coarse-graining. In the second part of the thesis, we analyze the problem of crystal structure prediction, by using quantum calculations.
(cont.) This is a fundamental problem in materials research and development, and it is typically addressed with highly accurate quantum mechanical computations on a small set of candidate structures, or with empirical rules that have been extracted from a large amount of experimental information, but have limited predictive power. In this thesis, we transfer the concept of heuristic rule extraction to a large library of ab-initio calculated information, and demonstrate that this can be developed into a tool for crystal structure prediction. In addition, we analyze the ab-initio results and prediction for a large number of transition-metal binary alloys.
by Stefano Curtarolo.
Ph.D.
Kwak, Seung-Keon. "New modeling and control design techniques for aircraft structural dynamics using smart materials /." The Ohio State University, 1999. http://rave.ohiolink.edu/etdc/view?acc_num=osu1488188894442033.
Повний текст джерелаRamzan, Muhammad. "Structural, Electronic and Mechanical Properties of Advanced Functional Materials." Doctoral thesis, Uppsala universitet, Materialteori, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-205243.
Повний текст джерелаSalahshoor, Pirsoltan Hossein. "Nanoscale structure and mechanical properties of a Soft Material." Digital WPI, 2013. https://digitalcommons.wpi.edu/etd-theses/924.
Повний текст джерела