Dissertations / Theses: 'Structure transition'

1

Redfern, C. M. "Electronic structure of transition metal complexes." Thesis, University of Oxford, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235094.

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2

Stillman, Kevin L. "Electronic structure studies of transition metal phosphides." Laramie, Wyo. : University of Wyoming, 2007. http://proquest.umi.com/pqdweb?did=1445042561&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.

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3

Andreescu, Florentina Carmen. "Transition, Nation, State, and Structure of Fantasy." Scholarly Repository, 2010. http://scholarlyrepository.miami.edu/oa_dissertations/413.

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This research aims to make evident the importance of films serving as a relevant arena for political struggles within a society, struggles that concern highly important concepts such as the nation and the state. This goal is accomplished by building upon the theory of cinematic nationhood and using the method of relational constructivism combined with insight from Lacanian psychoanalytic theory. The research regards films as forms of communication as well as forms of fantasy. The case this research focuses on is Romania. The case was selected because for a certain period of time the myths of nation and state had been strongly embedded-or nested-- within the social contexts-or commonplaces--specific to Marxism, namely work, equality, and the bourgeois enemy, followed by a swift and radical social discourse change that triggered changes within the topography of commonplaces. The films analyzed represent these changes in order to understand the specific ways in which the myth of nation and state are reflected within films produced during radical economic, social, and political transformations. This research reveals that, despite the social, economic, and political upheavals from the pre- to post-transition eras, the underlying national structure of fantasy remained remarkably unchanged, while the nation and the state changed their social relevance with changes in their position occupied within the structure of fantasy.

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4

Walters, Malcolm. "Efficient electronic structure calculations for transition metals." Thesis, University of Oxford, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270721.

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5

Harding, Daniel James. "Structure and reactivity of transition metal clusters." Thesis, University of Warwick, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.527439.

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6

Beer, N. R. "The electronic structure of transition metal alloys." Thesis, Imperial College London, 1985. http://hdl.handle.net/10044/1/37634.

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7

Mann, Peter David Alexander. "Electronic structure of layered transition metal oxides." Thesis, University of Cambridge, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.612888.

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8

Hermes, A. C. "Structure and reactivity of transition metal clusters." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:91e9449f-8c1e-4955-8c08-d9f24e5bbe6a.

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A range of computational and experimental techniques have been applied to the study of four metal cluster systems. Decorated rhodium clusters Rh n O m (N 2 O) + ( n = 4 − 8, m = 0 − 2) have been investigated both experimentally by IR-MPD and computationally using DFT. The effect of cluster size as well as oxygen coverage on the spectroscopy of the N 2 O bend are analyzed. The infrared-induced decomposition of N 2 O on Rh n O + m is observed on all cluster sizes, with marked differences as a function of size and oxygen coverage, particularly in the case of Rh 5 (N 2 O) + . The oxidation of CO was studied on the surface of small platinum cluster cations Pt n O + m ( n = 3 − 7, m = 2 , 4) by IR-MPD at 400 – 2100cm −1 . Spectroscopically, oxygen is found to be bound both dissociatively and molecularly on the cluster surface, while the CO band is found to red shift in cluster size, and blue shift with oxygen coverage. Oxidation of CO proceeds on all cluster sizes, with a constant branching ratio of 40% : 60% . DFT calculations identified key stationary points and barriers on the Pt 4 O 2 CO + reaction pathway. The one-colour Ta 2 photodissociation is studied by photoionization and VMI in the range 23500 – 24000cm −1 , finding clear evidence of a fragmentation process producing Ta , which is interpreted as fragmentation of cationic Ta + 2 at the two photon level. A majority of the observed channels produce either atomic ( Ta( 4 F 3/2 ) ) or cationic ( Ta + ( 5 F 1 ) ) ground state. An improved value for the dissociation energy D 0 ( Ta + 2 ) is obtained, in agreement with computational predictions. The anisotropies observed show weak evidence of a perpendicular transition being involved in the photodissociation process. Finally, the photodissociation dynamics of Cu 2 are studied by spectroscopy in the range 36000 – 38200cm −1 as well as VMI. Clear evidence for resonant photolysis of Cu 2 is obtained, as a result of both direct dissociation of the Cu + 2 2 Π ion state as well as dissociation of doubly excited Cu 2 states, which leads to a determination of dimer dissociation energies. Finally, the production of Cu + 2 is interpreted as evidence of photolysis of Cu 3 , from which a Cu 3 dissociation energy is derived.

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9

Krämer, Tobias. "Electronic structure of open-shell transition metal complexes." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:1f4a1330-281d-4696-b3e6-62b76fb41d65.

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This thesis presents electronic structure calculations on problems related to the bonding in inorganic coordination compounds and clusters. A wide range of molecules with the ability to exist in different structural forms or electronic states has been selected and density functional theory is systematically applied in order to gain detailed insight into their characteristics and reactivity at the electronic level. First, we address the question of redox non-innocent behaviour of bipyridine in a series of 1st row transition metal complexes. Complexes of the type [M(2,2'-bipyridine)(mes)₂]⁰ (M = Cr, Mn, Fe, Co, Ni; mes = 2,4,6-Me₃C6H₂) and their one-electron reduced forms have been explored. The results clearly show that the anions are best described as complexes of the monoanionic bipyridine radical (S_bpy = 1/2), giving a rationale for the observed structural changes within the ligand. Likewise, we have identified dianionic bipyridine in both the complexes [Zn2(4,4'-bpy)(mes)₄]²⁻ and [Fe(2,2'-bpy)₂]²⁻. In no case have we found evidence for significant metal-to-ligand backbonding. The subject of redox-noninnocence is further revisited in a comparative study of the two complexes [M(o-Clpap)₃] (M = Cr, Mo; o-Clpap = 2-[(2-chloro-phenyl)azo]-pyridine), and their associated electron transfer series. The results indicate that all electron transfer processes are primarily ligand-based, although in the case of the Mo analogue these are coupled to substantial electron density changes at the metal. The ability of pap to form radical anions finds a contrasting case in the di- nuclear Rh complex [Rh₂(μ-p-Clpap)₂ (cod)Cl₂], where the two ligand bridges act as acceptors of strong dπ∗ backbonding from a formally Rh^–I centre. We then direct our attention to the endohedral Zintl clusters [Fe@Ge₁₀]³⁻ and [Mn@Pb₁₂]³⁻, which reveal peculiar topologies. We have probed the electronic factors that influence their geometric preferences, and propose a model based on the shift of electron density from the endo- hedral metal to the cage to account for the observed geometries. Subsequently, we reassess the electronic structure of the xenophilic clusters Mn₂(thf)₄(Fe(CO)₄)₂ and [Mn(Mn(thf)₂)₃(Mn(CO)₄)₃]^–. We conclude that these are best viewed as exchange coupled Mn^II centres bridged by closed- shell carbonylate fragments. In the closing chapter the reduction of NO₂^– to NO by the complex [Cu(tct)(NO₂)]⁺ (tct = cis,cis-1,3,5-tris(cinnamylideneamino)cyclohexane) is studied, a process that mimics the enzyme-catalysed reaction. Two viable pathways for the reaction have been traced and key inter-mediates identified. Both direct release of NO or via decomposition of a Cu-NO complex are kinetically and thermodynamically feasible.

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10

Sameera, W. M. C. "Electronic structure of transition metal ions and clusters." Thesis, University of Glasgow, 2008. http://theses.gla.ac.uk/1389/.

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This thesis uses density functional theory (DFT) to explore the electronic structure and reaction mechanisms of open-shell transition metal ions and clusters. The early part of the thesis (Chapters 2 and 3) is devoted to high-valent metal-oxo species, both mono- and bimetallic, while Chapter 4 describes some aspects of copper-catalysed carbon-carbon bond formation. Finally, Chapter 5 highlights the role of DFT in computing magnetic and spectroscopic properties of exchange-coupled iron clusters. Whilst the chemistry contained in the thesis is rather diverse, the underlying theme of open-shell transition metal ions is common to all chapters. Moreover, we are primarily concerned with the ways in which interactions between two or more adjacent open-shells (either two metals or a metal and a ligand radical) control structure and reactivity. After a brief introduction to relevant theoretical aspects in Chapter 1, we use Chapter 2 to establish a link between the electronic structure of the high-valent Mn(V)=O porphyrin monomer species and their ability to perform oxidation reactions. The reaction profiles for oxidation of a range of substrates depend critically on the electronic structure of the isolated oxidant. Where the electronic ground state is genuinely best described as Mn(V)=O, the interaction between oxidant and substrate is repulsive at large separations, only becoming attractive when the incoming nucleophile approaches close enough to drive an electron out of oxide p manifold. In contrast, where the ground state is better described as an oxyl radical form, Mn(IV)-O.+, the oxidation occurs in sequential one-electron steps, the first of which is barrierless. In Chapter 3, we extend these ideas to bimetallic systems, where the presence of two high-valent manganese centres allows the system to oxidise water. Specifically, we focus on two model systems which have been shown to oxidise water, a Mn-porphyrin-based system synthesised by Naruta and a Mn-based system reported by McKenzie where the ligands contain a mixture of pyridine and carboxylate donors. In both cases, we again find that the emergence of oxyl radical character is the key to the reaction chemistry. However, the radical character is ‘masked’ in the electronic ground states, either by transfer of an electron from the porphyrin ring (Naruta) or by formation of a di-μ-oxo bridge (McKenzie system). In Chapter 4 we turn our attention to copper chemistry, and the role of copper complexes in catalysing atom transfer radical additions (Kharasch additions). In this reaction, the copper cycles between Cu(I) and Cu(II) oxidation states, and the result is the formation of a new C-C bonds. This Chapter makes extensive use of hybrid QM/MM techniques to model the environment of the copper centre in the target polypyrazolylborate-copper complexes (TpxCu). Finally, in Chapter 5 we consider the electronic structure, magnetic and spectroscopic properties of a pair of exchange-coupled Fe3 clusters, [Fe3(μ3-O)(μ-4-O2N-pz)6X3]2- (where pz = pyrazolato, X = Cl, Br). Our primary goal was to establish how well broken-symmetry DFT is able to reproduce the observed Mössbauer spectroscopic parameters, which are extensively used to identify the chemical environments of iron species and, in the case of mixed-valence clusters, to establish the degree of delocalisation of the additional electrons. In recent years DFT has proved able to compute these parameters with encouraging accuracy, but it is not clear to what extent the known deficiencies in broken-symmetry wavefunctions will compromise this ability. Our work suggests that neither the isomer shift nor the quadrupole splitting are strongly influenced by the nature of the coupling between the metal ions, suggesting that broken-symmetry solutions can be used as a basis for computing these parameters in more complex clusters.

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11

Disley, Helen Jane. "The electronic structure of transition metal dithiolene complexes." Thesis, University of Nottingham, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.478957.

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12

Payne, David J. "The Electronic Structure of Post Transition Metal Oxides." Thesis, University of Oxford, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.491678.

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The electronic structure of the oxides Pb02, In203, PbO and Bh03 have been studied using high resolution X-ray photoelectron spectroscopy (XPS), ultra-violet photoemission spectroscopy (UPS), hard X-ray photoelectron spectroscopy (HXPS), and X-ray emission (XES). These techniques are supported by band structure calculations carried out within the framework of density functional theory (DFT). It has been demonstrated using UPS, XPS and HXPS that the metallic nature l Trinity Term 2008. David J. Payne Submitted for the degree of Doctor of Philosophy Trinity College, Oxford. ,. ~!II ItI \IfI [l I ofPb02 arises from the occupation of conduction band states above the Fermi level of stoichiometric Pb02, most likely arising from oxygen vacancy defects. XPS and HXPS studies of the Pb 4/ core line show that strong satellites are observed at an energy consistent with the plasmon frequency observed in electron energy loss spectra. These satellites are not present in UPS measurements of the Pb 5d core line. It has been shown using XPS, HXPS, XES and DFT that the fundamental band gap for In203 is much smaller than the often quoted value of 3.75 eV. The fundamental band gap is direct, but direct optical transitions give minimal intensity until 0.81 eV below the valence band maximum. The results are consistent with a fundamental bandgap in the region of2.67eV. Structural distortions in post-transition metal oxides are often explained in terms of the influence of sp hybrid 'lone pairs'. XPS and XES measurements on a- PbO and a-Bh03 show that this model must be revised. A high density of metal 6s states is observed at the bottom of the valence band, and would therefore be unable to directly participate in hybridization with metal 6p states which lie above the valence band. These measurements are consistent with the results of density functional theory calculations.

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13

Zhang, Wenxu. "Magnetism, Structure and their Interactions." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2008. http://nbn-resolving.de/urn:nbn:de:bsz:14-ds-1215950409324-02446.

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In my work, magnetic and structural transitions of three categories of compounds are investigated by density functional calculations under local spin density approximation (LSDA). The first compound is Rh2MnGe with full Heusler structure at ambient condition. However, the structure is unstable at T=0 according to our calculations. A more stable structure we found is tetragonal one with either extension or compression along c-axis. The electronic reason of this distortion is the band Jahn-Teller effect where the Jahn-Teller active states are 4d states of Rh which is accidently put at the Fermi level by spin splitting. Then, magnetic moment behavior under pressure in itinerant compounds is investigated in four cubic Laves phase compounds (YFe2, ZrFe2, HfFe2, and LuFe2). The magnetic spin moment is decreased under pressure. A magnetic collapse where the spin moment vanishes is predicted under pressure around 20 GPa for Zr and Hf compounds, 40 GPa for Y and Lu compounds. The behavior of the magnetic moment is the result of competition between magnetic exchange interactions and kinetic energy during the compression of the volume, as described by the Stoner model. The last material investigated is CoO using LDSA+U in order to describe the strong Coulombic interaction of the transition metal ion. The pressure induced a magnetic transition, which was discovered in experiments, is explained by the competition between ligand field splitting and exchange energy. The ligand field splitting is increased under pressure, and suppresses the intraatomic exchange. As a result, the spin state changes from high spin to low spin, and at last to nonmagnetic state.

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14

Samuels, J. "The brittle to ductile transition in silicon." Thesis, University of Oxford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382682.

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15

Guo, Yuzheng. "Electronic structures of transition metal oxides." Thesis, University of Cambridge, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648465.

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16

Eng, Hank W. "The crystal and electronic structures of oxides containing d0 transition metals in octahedral coordination." Connect to this title online, 2003. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1070570079.

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Thesis (Ph. D.)--Ohio State University, 2003.
Title from first page of PDF file. Document formatted into pages; contains xx, 180 p.; also includes graphics. Includes bibliographical references (p. 139-145).

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17

Fine, David Andrew. "Structure and reactivity of dinuclear complexes of iridium /." Thesis, Connect to this title online; UW restricted, 1996. http://hdl.handle.net/1773/11618.

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18

Guo, G. Y. "Study of the electronic structures of layer-structure transition metal chalcogenides and their intercalation complexes." Thesis, University of Cambridge, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233953.

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In this thesis, we present results of studies of the electronic band structures and related electronic properties of some layered transition metal chalcogenides and their intercalation complexes. The materials investigated include group VIIc transition metal dichalcogenides, and 2H-TaS₂ and its lithium-, lead-, and tin-intercalated complexes, as well as dihafnium sulphide and selenide. Both experimental measurements and theoretical elect'onic band structure calculations have been carried out. The types of measurements conducted consist of reflectivity measurements in the energy range from 0.5 eV to 4.5 eV using the home-made reflectivity spectrometer, and electron energy loss measurements in the energy range up to 100 eV using the scanning transmission electron microscope as well as some characterization experiments (structural, chemical composition and thermal properties). The experimental investigations were restricted to the layered group VIIc metal dichalcogenides. All the electronic band structures are calculated using the linearized muffin-tin orbital (LMTO) method, and are reported for the first time except PdTe₂ and 2H-TaS₂. The obtained electronic band structures for the Ni-group metal dichalcogenides, and the semiconductor-metal shift in progression from PtS₂ through PtSe₂ to PtTe₂ are discussed in terms of the binding energies of the atomic valence orbitals of the constituent atoms, the local coordination of the metal atoms and the symmetry of the crystals as well as the charge transfer effects. A superlattice structural phase transition is proposed for PtSe₂, which may possibly explain the anomaly observed in the previous transport measurement. The previous photoemission spectra from NiTe₂, PdTe₂ and PtTe₂, and dHvA measurement on PdTe₂ are compared with their band structures in details, and a good agreement is found. Other available experimental data including the previous transport, optical and magnetic susceptibility measurements as well as the reflectivity and electron energy loss spectra measured in this work are also discussed in terms of these electronic structures. The band structure calculations for dihafnium chalcogenides predict that these materials are metals. They also suggest that there is a strong bonding between Hf atoms in the adjacent layers, thus giving rise to the rigidity in the c-direction which may preclude the intercalation of these materials. The results for 2H-TaS₂ and its intercalation complexes show that the rigid band model is essentially correct for 2H-LiTaS₂ but is an oversimplication for the post-transition metal intercalation compounds. Changes in the electronic structure upon intercalation are discussed in terms of the intercalant-host charge transfer and the hybridisation between the host states and the intercalation valence orbitals. Electrical conduction in 2H-PbTaS₂ and SnTaS₂ is found to be largely due to the p-valence electrons from the intercalant Pb (Sn) layers, resulting in the considerable increase in the superconducting transition temperature following intercalation. The results are also compared with the observed optical and transport properties and a broad agreement is found. The band structures and the electronic properties of other layered transition metal dichalcogenides and their intercalation complexes, as well as the band structure calculation techniques for the layered compounds are also reviewed in this thesis.

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19

Taylor, David Preston Landini Gregory. "Structure and transition towards an accretivist theory of time /." Iowa City : University of Iowa, 2009. http://ir.uiowa.edu/etd/443.

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20

Green, Pamela Rose. "The synthesis and structure of ternary transition metal sulphides." Thesis, University of Nottingham, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284056.

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21

Lacy, O. M. "Synthesis, structure and reactivity of polynuclear transition metal complexes." Thesis, University of Newcastle Upon Tyne, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370145.

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22

Pickup, David M. "The structure and characterisation of amorphous transition-metal chalcogenides." Thesis, University of Reading, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308039.

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23

Bull, Craig Lawrence. "Structure-property relationships of some mixed transition metal perovskites." Thesis, University College London (University of London), 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.417932.

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24

Whittell, George Robert. "Synthesis, structure and reactivity of transition metal-boryl complexes." Thesis, University of Bristol, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322606.

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25

SANTOS, ALEXANDRE JOSE DOS. "TREE-STRUCTURE SMOOTH TRANSITION VECTOR AUTOREGRESSIVE MODELS – STVAR-TREE." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2009. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=15888@1.

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COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
Esta dissertação tem como objetivo principal introduzir uma formulação de modelo não-linear multivariado, a qual combina o modelo STVAR (Smooth Transition Vector Autoregressive) com a metodologia CART (Classification and Regression Tree) a fim de utilizá-lo para geração de cenários e de previsões. O modelo resultante é um Modelo Vetorial Auto-Regressivo com Transição Suave Estruturado por Árvores, denominado STVAR-Tree e tem como base o conceito de múltiplos regimes, definidos por árvore binária. A especificação do modelo é feita através do teste LM. Desta forma, o crescimento da árvore é condicionado à existência de não-linearidade nas séries, que aponta a divisão do nó e a variável de transição correspondente. Em cada divisão, são estimados os parâmetros lineares, por Mínimos Quadrados Multivariados, e os parâmetros não-lineares, por Mínimos Quadrados Não-Lineares. Como forma de avaliação do modelo STVARTree, foram realizados diversos experimentos de Monte Carlo com o objetivo de constatar a funcionalidade tanto do teste LM quanto da estimação do modelo. Bons resultados foram obtidos para amostras médias e grandes. Além dos experimentos, o modelo STVAR-Tree foi aplicado às séries brasileiras de Vazão de Rios e Preço Spot de energia elétrica. No primeiro estudo, o modelo foi comparado estatisticamente com o Periodic Autoregressive (PAR) e apresentou um desempenho muito superior ao concorrente. No segundo caso, a comparação foi com a modelagem Neuro-Fuzzy e ganhou em uma das quatro séries. Somando os resultados dos experimentos e das duas aplicações conclui-se que o modelo STVAR-Tree pode ser utilizado na solução de problemas reais, apresentando bom desempenho.
The main goal of the dissertation is to introduce a nonlinear multivariate model, which combines the model STVAR (Smooth Transition Vector Autoregressive) with the CART (Classification and Regression Tree) method and use it for generating scenarios and forecasting. The resulting model is a Tree- Structured Vector Autoregressive model with Smooth Transition, called STVARTree, which is based on the concept of multiple regimes, defined by binary tree. The model specification is based on Lagrange Multiplier tests. Thus, the growth of the tree is conditioned on the existence of nonlinearity in the time series, which indicates the node to be split and the corresponding transition variable. In each division, linear parameters are estimated by Multivariate Least Squares, and nonlinear parameters by Non-Linear Least Squares. As a way of checking the STVAR-Tree model, several Monte Carlo experiments were performed in order to see the functionality of both the LM test and the model estimation. Best results were obtained with medium and large samples. Besides, the STVAR-Tree model was applied to Brazilian time series of Rivers Flow and electricity spot price. In the first study, the model was statistically compared to the Periodic Autoregressive (PAR) model and had a much higher performance than the competitor. In the second case, the model comparison was with Neural-Fuzzy Modeling and the STVAR-Tree model won in one of the four series. Adding both the experiments and the two applications results we conclude that the STVARTree model may be applied to solve real problems, having good results.

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26

Taylor, David Preston. "Structure and transition: towards an accretivist theory of time." Diss., University of Iowa, 2009. https://ir.uiowa.edu/etd/443.

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This dissertation is a defense of a particular theory of the metaphysics of time which I call "accretivism", but which is popularly known in a form usually called the "Growing Block Theory". The goal of a metaphysics of time is to incorporate the various aspects of our temporal experience into a single, comprehensive whole. To this end I delineate five aspects of our ordinary experience of time: 1) The Tensed Aspect, in virtue of which objects are presented to us as past, present, or future; 2) The Transitory Aspect, in virtue of which time passes or "flows"; 3) The Durational Aspect, in virtue of which entities have a certain temporal extent; 4) The Structural Aspect, in virtue of which entities are given as being in temporal relations to one another, and 5) The Differential-Repetitive Aspect, in virtue of which things are different from one time to another, and yet there is a certain recurrence of aspects of our experience form one time to another. I contrast the accretivist picture of time, according to which that which is past and that which is present both have ontological status, but nothing which is future has ontological status, and in which temporal passage consists in the coming-into-being of new entities at the temporal edge of reality marked by the present, with the two dominant theories of time in the contemporary literature: 1) presentism, according to which only that which is present has ontological status, and 2) four-dimensionalism, according to which time is to be understood on analogy with spatial dimensions. Accretivism, I argue, is superior to the other two views in virtue of the fact that it gives full status to both the Structural Aspect of Time, for which the presentist has difficulty accounting, and the Transitory Aspect of Time, for which the four-dimensionalist has difficulty accounting. I then defend the accretivist picture against a variety of objections that might be raised to it.

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27

Kim, Yang-Soo. "Electronic Structure and Chemical Bonding of Transition Metal Dichalcogenides." Kyoto University, 1999. http://hdl.handle.net/2433/181809.

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28

Zhang, Wenxu. "Magnetism, Structure and their Interactions." Doctoral thesis, Technische Universität Dresden, 2007. https://tud.qucosa.de/id/qucosa%3A23720.

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In my work, magnetic and structural transitions of three categories of compounds are investigated by density functional calculations under local spin density approximation (LSDA). The first compound is Rh2MnGe with full Heusler structure at ambient condition. However, the structure is unstable at T=0 according to our calculations. A more stable structure we found is tetragonal one with either extension or compression along c-axis. The electronic reason of this distortion is the band Jahn-Teller effect where the Jahn-Teller active states are 4d states of Rh which is accidently put at the Fermi level by spin splitting. Then, magnetic moment behavior under pressure in itinerant compounds is investigated in four cubic Laves phase compounds (YFe2, ZrFe2, HfFe2, and LuFe2). The magnetic spin moment is decreased under pressure. A magnetic collapse where the spin moment vanishes is predicted under pressure around 20 GPa for Zr and Hf compounds, 40 GPa for Y and Lu compounds. The behavior of the magnetic moment is the result of competition between magnetic exchange interactions and kinetic energy during the compression of the volume, as described by the Stoner model. The last material investigated is CoO using LDSA+U in order to describe the strong Coulombic interaction of the transition metal ion. The pressure induced a magnetic transition, which was discovered in experiments, is explained by the competition between ligand field splitting and exchange energy. The ligand field splitting is increased under pressure, and suppresses the intraatomic exchange. As a result, the spin state changes from high spin to low spin, and at last to nonmagnetic state.

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29

Felton, Solveig. "Tunable Magnetic Properties of Transition Metal Compounds." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-5939.

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30

Luedtke, Avery T. "Synthesis, structure, and reactivity of five-coordinate platinum(IV) complexes /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/11565.

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31

Tucker, Nigel Paul. "Magnetic structure of Gd thin-film surfaces." Thesis, University of Liverpool, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364156.

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32

Davidson, Isobel Jean. "Synthesis, structure and properties of selected lithiated transition metal oxides /." *McMaster only, 1996.

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33

Ma, Yue. "Double-strand breaks (DSBs) and structure transition on genome-sized DNA." Thesis, https://doors.doshisha.ac.jp/opac/opac_link/bibid/BB13097333/?lang=0, 2018. https://doors.doshisha.ac.jp/opac/opac_link/bibid/BB13097333/?lang=0.

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DNA中の二本鎖切断(DSB)に対するアスコルビン酸(AA)およびDMSOの保護効果を、蛍光顕微鏡による巨大DNA(T4 DNA; 166kbp)の単分子観察によって評価した。凍結／解凍の状態に対して3つの異なる形態の放射源、可視光、γ線、および超音波の環境下にさらした。1‐プロパノールと2‐プロパノールの間で異なる効果が表れた。ゲノムDNA分子の高次構造の変化は、1−プロパノールを用いると、長軸長が濃度60％で最小を示し、次にアルコール含有量の増加と共に増加する傾向があることを見出した。一方、2−プロパノールを用いると、長軸長はアルコール含有量の増加と共にほぼ単調な減少を示した。
The protective effect of ascorbic acid (AA) and DMSO against double-strand breaks (DSBs) in DNA was evaluated by single-molecule observation of giant DNA (T4 DNA; 166kbp) through fluorescence microscopy. Samples were exposed to three different forms of radiation: visible light, γ-ray, and ultrasound or freeze/thawing. The change of the higher-order structure of genomic DNA molecules in the presence of alcohols by use of single DNA observation with fluorescence microscopy, by focusing our attention to unveil the different effect between 1-propanol and 2-propanol.
博士(工学)
Doctor of Philosophy in Engineering
同志社大学
Doshisha University

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34

Nastar, Maylise. "Couplage entre structure électronique et structure cristalline : effet sur quelques propriétés des métaux de transition /." Gif-sur-Yvette : Service de documentation et d'édition multimédia, Centre d'études de Saclay, 1995. http://catalogue.bnf.fr/ark:/12148/cb35789647d.

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35

Nastar, Maylise. "Couplage entre structure electronique et structure cristalline : effet sur quelques proprietes des metaux de transition." Paris 6, 1994. http://www.theses.fr/1994PA066659.

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Nous presentons des calculs de diverses proprietes des metaux de transition a partir d'un modele de liaisons fortes. Nous mettons en evidence le role de la structure electronique, en presentant en fonction du remplissage en electrons d, les variations des stabilites relatives, des proprietes elastiques et des energies de formation de lacune. Les variations des constantes elastiques de cisaillement pur des structures cubiques a faces centrees (cfc), cubiques centrees (cc) et hexagonales compactes (hc), s'ecartent fortement d'une variation de type parabolique observee pour le module de compressibilite. Les tendances generales sont en tres bon accord avec les donnees experimentales et les calculs ab initio. En particulier, le modele decrit parfaitement le fort durcissement des constantes c' et c#4#4 des elements cfc de la colonne 9 (rh) et celui de la constante c' des elements cc entre la colonne 4 (zr) et la colonne 6 (mo). L'energie de formation de la lacune dans la structure cc varie fortement en fonction du remplissage et presente un maximum tres marque au voisinage du remplissage des elements de la colonne 6. Cet effet du remplissage explique en partie les fortes diminutions du coefficient d'autodiffusion entre la colonne 4 et la colonne 6. Nous montrons que le pseudo-gap de la densite d'etats de la structure cc est a l'origine du durcissement de la constante c' ainsi que du phonon nt#10,-1,1, de l'augmentation des differences d'energies cc-hc et cfc-hc et de la forte augmentation de l'energie de formation de la lacune entre zr et mo. En utilisant la methode de recursion, nous constatons que les principales tendances des grandeurs etudiees sont reproduites avec peu de moments de la densite d'etats (environ 6). En revanche, des details comme les singularites des constantes elastiques, n'apparraissent qu'avec un calcul exact de la densite d'etats

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36

Clayton, Thomas Willets. "The correlation of structure, reactivity and physical properties with electronic structure in transition metal complexes /." The Ohio State University, 1989. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487671108308527.

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37

Attfield, J. P. "The structural and magnetic properties of some transition metal compounds." Thesis, University of Oxford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379913.

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38

Knee, Christopher Sebastian. "Synthesis, structure and magnetic properties of complex metal oxides." Thesis, University of Southampton, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299519.

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39

Zhou, Shengqiang. "Transition metal implanted ZnO: a correlation between structure and magnetism." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2008. http://nbn-resolving.de/urn:nbn:de:bsz:14-ds-1209998012687-36583.

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Nowadays ferromagnetism is often found in potential diluted magnetic semiconductor systems. However, many authors question the origin of this ferromagnetism, i.e. if the observed ferromagnetism stems from ferromagnetic precipitates rather than from carriermediated magnetic coupling of ionic impurities, as required for a diluted magnetic semiconductor. In this thesis, this question will be answered for transition-metal implanted ZnO single crystals. Magnetic secondary phases, namely metallic Fe, Co and Ni nanocrystals, are formed inside ZnO. They are - although difficult to detect by common approaches of structural analysis - responsible for the observed ferromagnetism. Particularly Co and Ni nanocrystals are crystallographically oriented with respect to the ZnO matrix. Their structure phase transformation and corresponding evolution of magnetic properties upon annealing have been established. Finally, an approach, pre-annealing ZnO crystals at high temperature before implantation, has been demonstrated to sufficiently suppress the formation of metallic secondary phases.

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40

Flood, Kelly-Jayne. "Comparative X-ray Structure Analyses of Multidentate Transition Metal Complexes." Thesis, University of Canterbury. Chemistry, 2006. http://hdl.handle.net/10092/1390.

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The biological significance of macrocyclic complexes has been recognized since they were first synthesized by Neil Curtis. They have the potential to play a critical role in mimicking metalloprotein active sites. Nine Curtis macrocyclic complexes have been studied using X-ray crystallographic techniques. Their structures have been solved and comparisons of the results have been made. Biological importance is also true of the macrocyclic counterpart; side-off and end-off compartmental ligands. In some circumstances these types of ligands are more appropriate because they have extra flexibility due to their pendant arms not being fixed in place by another head-unit, like a traditional macrocycle. The synthesis of a proposed compartmental ligand; 2,2-(N,Nʼ-bis(benzimidazole-2-ylmethyl)methylamine-5,5ʼ-di-tert-butyl-3,3ʼmethanediyl-dibenzyl alcohol (Ligand 1(L1)), has been proposed and outlined. The pendant arms: bis(benzimidazole-2-ylmethyl)amine (BBIM), were successfully synthesized and characterized with 1H NMR, IR and X-ray crystallography. The head-unit: 5,5ʼ-Di-tert-butyl-2,2ʼ-dihydroxy-3,3ʼ-methanediyl-dibenzene methanol (DHTMBA), of L1 was synthesized and characterized using 1H NMR, IR and mass spectrometry. A similar head-unit; 5,5ʼ-Di-methyl-2,2ʼ-dihydroxy-3,3ʼ-methanediyl-dibenzene methanol (DHMMBA), was synthesized in an effort to shorten the synthetic time of the head-unit. This was consequently converted to the chlorine analogue; 3,3ʼ-Bis(chloromethyl)-5,5ʼ-dimethyl-2,2ʼ-methane-diyldiphenol (Cl-DHMMB), and characterized with 1H NMR, IR and X-ray crystallography. Efforts were made to synthesize Ligand 1, but due to synthetic difficulties and time restraints this proved unsuccessful. Suggestions have been made to develop this synthesis.

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41

Davidson, Isobel Jean. "Synthesis, structure and properties of selected lithiated transition metal oxides." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape16/PQDD_0018/NQ30131.pdf.

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42

Taylor, J. M. C. "The structure and properties of some mixed transition metal oxides." Thesis, University of Oxford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382735.

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43

Motru, Hema Venkata Veerendra Suneel. "Electronic structure at the cores of dislocations in transition metals." Thesis, University of Liverpool, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.539587.

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44

Kaviani, Saeid. "Processing, structure and properties of ordered iron-transition metal aluminides." Thesis, University of Sheffield, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.286875.

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45

Waldron, Joanna Elizabeth Leah. "Synthesis, structure and physical properties of selected transition metal oxides." Thesis, University College London (University of London), 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368892.

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46

West, B. C. "Structure and dynamics in transition metal oxides and insertion compounds." Thesis, University of Exeter, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379466.

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47

Liu, Hui-Ping. "Magnetic ordering and crystal structure in selected transition-metal compounds /." Uppsala : Acta Universitatis Upsaliensis, 1999. http://catalogue.bnf.fr/ark:/12148/cb402057270.

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48

Campisi, Donna Barton Jacqueline K. "Transition metal complexes as probes of DNA sequence-dependent structure /." Diss., Pasadena, Calif. : California Institute of Technology, 1996. http://resolver.caltech.edu/CaltechETD:etd-09082006-114255.

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49

Zhou, Shengqiang. "Transition metal implanted ZnO: a correlation between structure and magnetism." Doctoral thesis, Technische Universität Dresden, 2007. https://tud.qucosa.de/id/qucosa%3A23718.

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Nowadays ferromagnetism is often found in potential diluted magnetic semiconductor systems. However, many authors question the origin of this ferromagnetism, i.e. if the observed ferromagnetism stems from ferromagnetic precipitates rather than from carriermediated magnetic coupling of ionic impurities, as required for a diluted magnetic semiconductor. In this thesis, this question will be answered for transition-metal implanted ZnO single crystals. Magnetic secondary phases, namely metallic Fe, Co and Ni nanocrystals, are formed inside ZnO. They are - although difficult to detect by common approaches of structural analysis - responsible for the observed ferromagnetism. Particularly Co and Ni nanocrystals are crystallographically oriented with respect to the ZnO matrix. Their structure phase transformation and corresponding evolution of magnetic properties upon annealing have been established. Finally, an approach, pre-annealing ZnO crystals at high temperature before implantation, has been demonstrated to sufficiently suppress the formation of metallic secondary phases.

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50

Norris, Caroline. "The structure, reactivity and spectroscopy of selected transition metal complexes." Thesis, University of Sussex, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.496790.

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This thesis focuses on the structure, reactivity and spectroscopy of metal complexes, as investigated using both DFT and ab initio methods, with a particular emphasis on the elucidation of experimental data. The first results chapter. Chapter 3, describes the electronic structure and spectroscopy of [Zn(pyridine)₄]²⁺, as calculated using TDDFT, to aid the interpretation and assignment of the first recorded state-resolved gas-phase photofragmentation spectrum of a dicationic transition-metal complex.

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Dissertations / Theses on the topic 'Structure transition'

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