Dans les réacteurs industriels ou dans la nature, l'écoulement de fluides peut être couplé à des réactions chimiques. Dans de nombreux cas, il en résulte l'apparition de structures complexes dont les propriétés dépendent entre autres de la géométrie du système.<p><p>Dans ce contexte, le but de notre thèse a été d'étudier de manière théorique et sur des modèles réaction-diffusion-convection simples les propriétés de dynamiques spatio-temporelles résultant du couplage chimie-hydrodynamique. <p>Nous nous sommes focalisés sur les instabilités hydrodynamiques de digitation visqueuse et de densité qui apparaissent respectivement lorsqu'un fluide dense est placé au-dessus d'un fluide moins dense dans le champ de gravité et lorsqu'un fluide visqueux est déplacé par un fluide moins visqueux dans un milieu poreux.<p><p>En particulier, nous avons étudié les problèmes suivants:<p>- L'influence d'une réaction chimique de type A + B → C sur la digitation visqueuse. Nous avons montré que les structures formées lors de cette instabilité varient selon que le réactif A est injecté dans le réactif B ou vice-versa si ces réactifs n'ont pas un coefficient de diffusion ou une concentration initiale identiques.<p>- Le rôle de pertes de chaleur par les parois du réacteur dans le cadre de la digitation de densité de fronts autocatalytiques exothermiques. Nous avons caractérisé les conditions de stabilité de fronts en fonction des pertes de chaleur et expliqué l'apparition de zones anormalement chaudes lors de cette instabilité.<p>- L'influence de l'inhomogénéité du milieu sur la digitation de densité de solutions réactives ou non. Nous avons montré que les variations spatiales de perméabilité d'un milieu poreux peuvent figer ou faire osciller la structure de digitation dans certaines conditions.<p>- L'influence d'un champ électrique transverse sur l'instabilité diffusive et la digitation de densité de fronts autocatalytiques. Il a été montré que cette interaction peut donner lieu à des nouvelles structures et changer les propriétés du front.<p><p>En conclusion, nous avons montré que le couplage entre réactions chimiques et mouvements hydrodynamiques est capable de générer de nouvelles structures spatio-temporelles dont les propriétés dépendent entre autres des conditions imposées au système.<p>/<p>In industrial reactors or in nature, fluid flows can be coupled to chemical reactions. In many cases, the result is the emergence of complex structures whose properties depend among others on the geometry of the system.<p>In this context, the purpose of our thesis was to study theoretically using simple models of reaction-diffusion-convection, the properties of dynamics resulting from the coupling between chemistry and hydrodynamics.<p><p>We focused on the hydrodynamic instabilities of viscous and density fingering that occur respectively when a dense fluid is placed above a less dense one in the gravity field and when a viscous fluid is displaced by a less viscous fluid in a porous medium.<p><p>In particular, we studied the following issues:<p>- The influence of a chemical reaction type A + B → C on viscous fingering. We have shown that the fingering patterns observed during this instability depends on whether the reactant A is injected into the reactant B or vice versa if they do not have identical diffusion coefficients or initial concentrations.<p>- The role of heat losses through the reactor walls on the density fingering of exothermic autocatalytic fronts. We have characterized the conditions of stability of fronts depending on heat losses and explained the appearance of unusually hot areas during this instability.<p>- The influence of the inhomogeneity of the medium on the density fingering of reactive solutions or not. We have shown that spatial variations of permeability of a porous medium may freeze or generate oscillating fingering pattern under certain conditions.<p>- The influence of a transverse electric field on the Rayleigh-Taylor and diffusive instabilities of autocatalytic fronts. It was shown that this interaction may lead to new structures and may change the properties of the front.<p><p>In conclusion, we showed that the coupling between chemical reactions and hydrodynamic motions can generate new space-time structures whose properties depend among others, on the conditions imposed on the system. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

Orientadores: Narcizo Marques de Souza Neto, Flávio Cesar Guimarães Gandra / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin / Made available in DSpace on 2018-08-27T10:57:14Z (GMT). No. of bitstreams: 1 Veiga_LarissaSayuriIshibe_D.pdf: 10330689 bytes, checksum: 72bdd1a8fad1f82f880bb2c86fcd6a9e (MD5) Previous issue date: 2015 / Resumo: Este trabalho teve como objetivo a investigação de diversos mecanismos físicos provenientes das estruturas eletrônicas, magnéticas e cristalinas de sistemas ternários de terras raras e metais de transição 3d-5d através do uso das técnicas de espectroscopia de absorção de raios X e difração de raios X sob altas pressões. Dentre os fenômenos físicos estudados em função da compressão da rede cristalina induzida pela aplicação da pressão estão o magnetismo proveniente dos orbitais 4f e 5d nos sistemas ternários RERh4B4 (com RE = Dy e Er), os efeitos do campo elétrico cristalino e as interações de troca magnéticas nas perovskitas duplas 3d-5d (AFeOsO6, com A = Ca e Sr) e o acoplamento spin-órbita nos metais de transição 5d. As propriedades eletrônicas e magnéticas dos orbitais 4f e 5d das terras raras nos compostos da família RERh4B4 (RE = Dy e Er) foram investigadas através de experimentos de XANES e XMCD sob altas pressões na borda L3 do Dy e Er . Os sinais magnéticos das contribuições quadrupolar (2p3/2-> 4f) e dipolar (2p3/2->5d) presentes nos espectros de XMCD, em ambos os compostos, diminuem progressivamente em função da pressão. Este comportamento foi explicado em termos das interações de troca magnéticas entre os íons de terras raras, que são enfraquecidas pelas alterações locais da estrutura atômica induzidas pela compressão da rede cristalina. Já no sistema de perovskitas duplas, foi demonstrado que a compressão da estrutura Sr2FeOsO6, com um arranjo cristalino ordenado dos íons de Fe (3d) e Os (5d), permite o controle contínuo e reversível da coercividade e magnetização de saturação. Este efeito foi explicado em termos do aumento do campo elétrico cristalino em função da pressão, que altera as interações de troca magnéticas Fe-O-Os e transforma o material com magnetização remanente e coercividade praticamente nulas a pressão ambiente em outro com uma coercividade robusta (~0.5 T) e magnetização de saturação expressiva a pressões acima de ~10 GPa. Por fim, a última parte desta tese de doutorado foi dedicada ao uso da seletividade química e orbital da técnica de XANES na investigação do acoplamento spin-órbita nos elementos Pt (Pt0, 5d9) e Hf (Hf0, 5d2) sob altas pressões. Ao contrário do observado para a Pt, o cálculo do branching ratio a partir dos espectros de absorção nas bordas L2,3 do Hf revelaram que o acoplamento spin-órbita aumenta monotonicamente em função da pressão aplicada. Esse comportamento foi relacionado às propriedades supercondutoras e estruturais presentes nesse elemento sob altas pressões / Abstract: The scientific goal of this work has been the investigation of several physical mechanisms derived from the electronic, magnetic and structural properties of ternary rare earth and transition metal systems by means of X-ray absorption spectroscopy and X-ray diffraction techniques in a diamond anvil cell. Among the physical properties studied as a function of lattice compression induced by applied pressure are the magnetism of the 4f and 5d orbitals in tetragonal rare earth rhodium borides RERh4B4 (with RE = Dy e Er), the crystal electric field effects and magnetic exchange interactions in 3d-5d double perovskite systems (A2FeOsO6, with A = Ca e Sr) and the spin-orbit coupling in 5d transition metals. The electronic and magnetic properties of the rare earth 4f and 5d orbitals in the RERh4B4 (RE = Dy e Er) systems were investigated through high pressure XANES and XMCD experiments at Dy and Er L3 edges. For both compounds, the magnetic signals of the quadrupole (2p3/2->4f) and dipole (2p3/2->5d) contributions to the XMCD spectra progressively decrease as a function of pressure. This behavior was explained in terms of the magnetic exchange interactions between the rare earth ions, which are weakened by changes in the local atomic structure induced by compression of the crystal lattice. In the double perovskite system, it has been shown that compression of Sr2FeOsO6 structure with an ordered crystalline arrangement of iron (3d) and osmium (5d) transition metal ions, allows for continuous and reversible control of magnetic coercivity and saturation magnetization. This effect was explained in terms of enhanced crystal electric fields under high pressure, which alter the Fe-O-Os magnetic exchange interactions and transform the material with an otherwise mute response to magnetic fields into one with a strong coercivity (~0.5 T) and substantial saturation magnetization at pressures above ~10 GPa. Finally, the last part of this thesis is dedicated to the use of chemical and orbital selectivity of XANES technique as a tool to investigate the spin-orbit coupling in Pt (Pt0, 5d9) and Hf (Hf0, 5d2) elements under high pressures. Unlike observed for Pt, the calculated branching ratio determined from the integrated intensities of the Hf L2,3 white lines shows that the spin-orbit coupling increases monotonically as a function of applied pressure. This behavior was related to the superconducting and structural properties displayed by this element at high pressures / Doutorado / Física / Doutora em Ciências

Dans cette thèse je me suis intéressé au caractère relativiste de matériaux topologiques tridimensionnels : les semi-métaux de Weyl et les isolants topologiques. Après une introduction aux états de surfaces et aux matériaux topologiques, je discute leurs propriétés de covariance sous les rotations trigonométriques et hyperboliques. Ces transformations me permettent de traiter les équations du mouvement d'un électron dans un champ magnétique ou à la surface, sous l'influence d'un champ électrique ou d'une inclinaison de la relation de dispersion. En première partie, je l'illustre dans le cas de la réponse magnéto-optique des semi-métaux de Weyl, en présence d'une inclinaison. Ces calculs sont en lien avec ma collaboration avec les expérimentateurs du LNCMI à Grenoble pour la caractérisation de la structure de bande de Cd₃As₂ où l'on montre que ce matériau est un semi-métal de Kane et non un semi-métal de Dirac dans la gamme de potentiels chimiques expérimentalement accessible. L'autre partie de cette thèse porte sur les états de surface des isolants topologiques où l'on montre qu'il existe des états de surface massifs au-delà de l'état de surface chiral. Ces états semblent avoir été observés par des études en ARPES d'échantillons de Bi₂Se₃ et Bi₂Te₃ oxydés et par des mesures de transport sur HgTe déformé. J'ai ainsi eu l'occasion de travailler avec les expérimentateurs du LPA à Paris sur le comportement des états de surface de HgTe sous forts effets de champ. Je termine par une discussion des états à l'interface entre un semi-métal de Weyl et un isolant dans le cas où le gap de ce dernier est suffisamment petit pour observer l'effet d'un champ magnétique et d'une inclinaison de la relation de dispersion sur les états de surface. / During my PhD studies I focused on the relativistic properties of threedimensional topological materials, namely Weyl semimetals and topological insulators. After introducing surface states and topological materials I discuss their covariance in trigonometric and hyperbolic rotations. These transformations help to solve the equations of motion of an electron in a magnetic field or at the surface with an applied electric field or with a tilt in the band dispersion. In a first place, I illustrate these transformations for the magneto-optical response of tilted Weyl semimetals. This work is related to my collaboration with experimentalists at LNCMI, Grenoble for characterizing the band structure of Cd₃As₂ where we show that this material is a Kane semi-metal instead of a Dirac semi-metal in the experimentally accessible range of chemical doping. The other part of this thesis is concerned with the surface states of topological insulators. I show that massive surface states can also exist in addition to the chiral surface state due to band inversion. Such states may have already been observed in ARPES measurement of oxidized Bi₂Se₃ and Bi₂Te₃ and in transport measurement of strained bulk HgTe. I show the work we performed with experimentalists at LPA, Paris on the behavior of HgTe surface states for strong field effects. Finally, I discuss the states at the interface of a Weyl semimetal and a small gap insulator. In this situation, an applied magnetic field or the tilt of the band dispersion can strongly affect the observed surface states.

Electric and magnetic fields in the vicinity of strong sources of radiation (e.g. radar and broadcasting) can exceed the limits mentioned in the national standards for the exposition of persons. Field probes are needed to warn personnel if they are going too close to the RF-sources. For acceptance reasons the field probes should be universal in such a way that no user adjustment of frequency is required. The limits for power density, electric and magnetic field strength depend on the frequency. In contrast, field probes covering a large frequency range, e.g. 1 MHz to 18 GHz or even larger, normally have a flat frequency response. Therefore, the person using the field probe has to know the frequency of the electromagnetic field and to evaluate fieldstrength with respect to the frequency dependent limit value defined by law. Human mistakes while making that evaluation can lead to expositions above the limit value. On the other hand, the evaluation of the power density in the presence of multiple strong sources of radiation at different frequencies with different limit values also leads to measurement problems. A new approach has been undertaken to overcome these difficulties in the development of a rectifying field probe. It consists in shaping the antenna factor of the probe inversely proportional to the limit value. The isotropic response of field probes can be achieved, if three dipole antennas are arranged perpendicular to each other. The presence of dielectric supporting material leads to degradation of the isotropic response of such a field probe. The effect will be investigated. For typical substrates the isotropic response is degraded by up to 3.8 dB. An compensation for this effect will be proposed that leads to a residual unisotropic response of less than 0.2 dB.

This master's thesis describes process of design and development of the system for calculating the coverage of wireless networks, it is implemented as a web portal and written in the Java programming language. The text of the thesis describes the work with the used platforms, a description of the ITU-R calculation method P.1812, which is used for calculation electric field strength and basic information about electromagnetic waves. The main function of the system is to calculate and display coverage of wireless networks and customer management information.

Tématem této práce je počítačové modelování organického elektrochemického tranzistoru (OECT). Pro vytvoření modelu bylo třeba vypočítat rozložení elektrického pole a koncentrace iontů elektrolytu. Výpočet byl proveden numericky pomocí metody konečných prvků. Bylo vypočítáno rozložení elektrického potenciálu na povrchu kanálu OECT, dále byly vypočítány změny vodivosti a výstupní proud OECT. Výpočty byly provedeny na osobním počítači pomocí komerčního softwaru COMSOL Multiphysics. Kvůli nedostatečnému výpočetnímu výkonu musel být model rozdělen na části a drasticky zjednodušen. Prezentované výsledky se liší od literatury, protože se nepodařilo správně modelovat saturaci tranzistoru. Odchylky od reálného chování OECT jsou pravděpodobně způsobeny zjednodušením modelu.

This master's thesis deals with the analysis of the optical power measurement using an optical fiber sensor. The thesis contains the theoretical background to understand the origin of polarization and its representation in space using Poincaré’s sphere and Stokes vectors. There is also a part describing optical performance measurement and the preview of analog measurements from various researches. Practical part focuses on verification of changes of fiber sensor parameters at temperature change in its surroundings and this part includes also additional suggestions for various types of measurements and verification of the function of the photodiode as an optical power transducer. Most measurements are based on the comparison of results obtained with the polarimeter. The results were plotted and discussed.

Diploma thesis treat of effect of direct, alternate and pulse electrical stress on the properties surveyed electrical insulating material. Object of this experiment is crystalline high-density polystyrene QUINN PS. To monitor the stress is used the method of dielectric relaxation spectroscopy. Under examinations are the resultant dielectric spectra, which constitute the frequency dependencies of components of complex permitivity. Samples of the selected material are exposed to effects of alternate and pulse electrical stress on the different intensities of the electric field. In the direct field are then monitored absorption characteristics and specific volume resistance of the samples.

<p>U&nbsp; disertaciji&nbsp; je&nbsp; sprovedeno&nbsp; teorijsko&nbsp; istraživanje&nbsp; fizičko-hemijskih&nbsp; svojstava&nbsp;elektronskog podsistema molekula sumanena. Proračuni su sprovedeni u okvirima DFT i TDDFT&nbsp; teorije&nbsp; sa&nbsp; B3LYP&nbsp; funkcionalom&nbsp; i&nbsp; 6-31Gd,&nbsp; 6-31Gdp i&nbsp; 6-31++Gdp&nbsp; bazisom.&nbsp; Za&nbsp; sve&nbsp;proračune&nbsp; u&nbsp; okvirima&nbsp; navedenog&nbsp; nivoa&nbsp; teorije,&nbsp; kori&scaron;ćen&nbsp; je&nbsp; softverski&nbsp; paket&nbsp; Gaussian03.&nbsp;Ispitana&nbsp; su:&nbsp; strukturna&nbsp; i&nbsp; optička&nbsp; (zajedno&nbsp; sa&nbsp; nelinearnim)&nbsp; svojstva&nbsp; sumanena&nbsp; i&nbsp; njegovih&nbsp;derivata dobijenih modifikovanjem sa atomima bora iazota, aromatična i inverziona svojstva&nbsp;svojstva&nbsp; sumanena&nbsp; i&nbsp; njegovih&nbsp; derivata,&nbsp; adsorpciona&nbsp; svojstva&nbsp; sumanena&nbsp; prema&nbsp; molekulima&nbsp;H₂, CO, CO_2&nbsp;i NH_3&nbsp;i uticaj spolja&scaron;njeg električnog polja na svojstva sumanena.</p><p>Prema&nbsp; dobijenim&nbsp; rezultatima,&nbsp; fundamentalna&nbsp; fizičko-hemijska&nbsp; svojstva&nbsp; molekula&nbsp;<br />sumanena mogu se efikasno i fino pode&scaron;avati supstitucijom i disupstitucijom hetero-atomima&nbsp;bora&nbsp; i&nbsp; azota.&nbsp; Dubina&nbsp; i&nbsp; inverziona&nbsp; barijera&nbsp; sumanena se&nbsp; na&nbsp; ovaj&nbsp; način&nbsp; može&nbsp; menjati&nbsp; u&nbsp; oba&nbsp;smera.&nbsp; Pokazalo&nbsp; se&nbsp; da&nbsp; su&nbsp; ova&nbsp; dva&nbsp; parametra&nbsp; u&nbsp; korelaciji,&nbsp; s&nbsp; obzirom&nbsp; da inverziona&nbsp; barijera&nbsp;skoro potpuno zavisi od dubine sumanena. Slično je i sa aromatičnim svojstvima prstenova,&nbsp;koja se u zavisnosti od broja uvedenih hetero-atomamenja od aromatične preko nearomatične&nbsp;do antiaromatične prirode. Optička svojstva su, pomenutim modifikacijama, takođe značajno&nbsp;pobolj&scaron;ana: apsorpcioni pikovi kod UV/Vis spektra se pomeraju ka vidljivoj oblasti, dok je&nbsp;hiperpolarizibilnost&nbsp; sumanena&nbsp; i&nbsp; derivata&nbsp; sa&nbsp; jednim&nbsp; atomom&nbsp; bora&nbsp; vi&scaron;a&nbsp; od&nbsp; referentnog&nbsp;molekula uree, respektivno, 9 i 49 puta.</p><p>Prema dobijenim rezultatima, adsorpciona svojstva sumanena su veoma kompetitivna&nbsp;sa&nbsp; ostalim&nbsp; organskim&nbsp; molekulima&nbsp; kao&nbsp; &scaron;to&nbsp; su&nbsp; ugljenične&nbsp; nanotube&nbsp; i&nbsp; fuleren&nbsp; C₆₀,&nbsp; usled&nbsp;postojanja&nbsp; značajnog&nbsp; dipolnog&nbsp; momenta&nbsp; zbog&nbsp; specifične&nbsp; geometrije.&nbsp; Posebno&nbsp; se&nbsp; ističu&nbsp;pozitivna adsorpciona svojstva prema molekulima H_2&nbsp;<br />i CO. Dok je prvo pomenuti bitan sa&nbsp;energetskog&nbsp; aspekta,&nbsp; specifičnost&nbsp; drugog&nbsp; molekula&nbsp; se&nbsp; ogleda&nbsp; u&nbsp; činjenici&nbsp; da&nbsp; ne&nbsp; može&nbsp; biti&nbsp;adsorbovan od strane ugljeničnih nanotuba.&nbsp;</p><p>Potencijal sumanena, posebno u oblasti organske elektronike, dodatno ističu i rezultati&nbsp;ispitivanja&nbsp; uticaja&nbsp; spolja&scaron;njeg&nbsp; električnog&nbsp; polja.&nbsp; Naime,&nbsp; dobijeni&nbsp; rezultati&nbsp; ukazuju&nbsp; da&nbsp; se&nbsp;specifična&nbsp; (posebno&nbsp; adsorpciona)&nbsp; svojstva&nbsp; sumanena&nbsp; mogu&nbsp; dodatno&nbsp; pobolj&scaron;ati&nbsp; primenom&nbsp;slabog, i eksperimentalno lako ostvarljivog, električnog &nbsp;polja, jer se intenzivira razdvajanje&nbsp;naelektrisanja.</p> / <p>Theoretical&nbsp; investigation&nbsp; of&nbsp; physicochemical&nbsp; properties&nbsp; of&nbsp; electron&nbsp; subsystem&nbsp; of&nbsp;sumanene&nbsp; molecule&nbsp; has&nbsp; been&nbsp; conducted&nbsp; in&nbsp; this&nbsp; doctoral&nbsp; work.&nbsp; Calculations &nbsp;are&nbsp; performed&nbsp;within DFT and TD-DFT with B3LYP functional and 6-31Gd, 6-31Gdp i &nbsp; 6-31++Gdp basis&nbsp;sets. For all calculations, on the mentioned level of theory, Gaussian03software package was&nbsp;used.&nbsp; Investigation&nbsp; encompassed:&nbsp; structural &nbsp; and&nbsp; optical&nbsp; (including&nbsp; nonlinear)&nbsp; properties&nbsp; of&nbsp;sumanene&nbsp; and&nbsp; its&nbsp; derivatives&nbsp; obtained&nbsp; by&nbsp; modification&nbsp; with&nbsp; boron&nbsp; and&nbsp; nitrogen&nbsp; atoms,&nbsp;aromatic and bowl to bowl inversion properties of sumanene and its derivatives, adsorption&nbsp;properties of sumanene towards H₂, CO, CO_2&nbsp;i NH_3&nbsp;molecules and the influence of external&nbsp;electric field to the properties of sumanene.</p><p>According to obtained results, fundamental physicochemical properties of sumanene&nbsp;molecule could be efficiently and finely adjusted with the monosubstitution and disubstitution&nbsp;with&nbsp; hetero-atoms&nbsp; of&nbsp; boron&nbsp; and&nbsp; nitrogen.&nbsp; Bowl&nbsp; depth and&nbsp; bowl&nbsp; to&nbsp; bowl&nbsp; inversion&nbsp; barrier&nbsp;could&nbsp; be&nbsp; tuned&nbsp; in&nbsp; both&nbsp; directions.&nbsp; It&nbsp; was&nbsp; demonstrated&nbsp; that&nbsp; these&nbsp; two&nbsp; parameters&nbsp; are&nbsp;correlated, since bowl to bowl inversion barrier principally depends on the fourth power of&nbsp;bowl&nbsp; depth.&nbsp; Similar&nbsp; situation&nbsp; is&nbsp; with&nbsp; aromatic&nbsp; nature&nbsp; of&nbsp; sumanene&nbsp; rings,&nbsp; which&nbsp; change,&nbsp;depending&nbsp; on&nbsp; the&nbsp; number&nbsp; of&nbsp; introduced&nbsp; boron&nbsp; and&nbsp; nitrogen&nbsp; atoms,&nbsp; from&nbsp; aromatic&nbsp; through&nbsp;non-aromatic&nbsp; towards&nbsp; anti-aromatic&nbsp; nature.&nbsp; Thanks&nbsp; to&nbsp; mentioned&nbsp; modifications,&nbsp; optical&nbsp;properties&nbsp; are&nbsp; improved&nbsp; as&nbsp; well:&nbsp; absorption&nbsp; peaks&nbsp; in&nbsp; UV/Vis&nbsp; spectra&nbsp; shift&nbsp; towards&nbsp; visible&nbsp;area,&nbsp; while&nbsp; hyperpolarizabilities&nbsp; of&nbsp; sumanene&nbsp; and&nbsp; its&nbsp; derivative&nbsp; containing&nbsp; one&nbsp; boron&nbsp; atom&nbsp;are higher than hyperpolarizability of referent molecule of urea, respectively, 9 and 49 times.&nbsp;</p><p>Thanks&nbsp; to&nbsp; significant&nbsp; dipole&nbsp; moment&nbsp; due&nbsp; to&nbsp; the&nbsp; specific&nbsp; geometry, &nbsp;nvestigated &nbsp;adsorption properties of sumanene are very competitive to the other &nbsp;organic molecules such&nbsp;as carbon nanotubes and fullerene C₆₀. Positive adsorption properties of sumanene towards H_2&nbsp;and CO molecules are distinguished. While the H_2&nbsp;molecule is important from the energetic&nbsp;aspects, specificity of CO molecules is that it can&rsquo;t be adsorbed by carbon nanotubes.</p><p>Potential&nbsp; of&nbsp; sumanene,&nbsp; especially&nbsp; in&nbsp; the&nbsp; field&nbsp; of&nbsp; organic&nbsp; electronics,&nbsp; is &nbsp;emphasized&nbsp;through the obtained results related to the investigation of the influence of external electric&nbsp;field.&nbsp; Obtained&nbsp; results&nbsp; indicate&nbsp; that&nbsp; specific&nbsp; (especially&nbsp; adsorption)&nbsp; properties&nbsp; of&nbsp; sumanene&nbsp;could be additionally improved by application of &nbsp;weak, and experimentally easily achievable,&nbsp;external electric field, due to the higher charge separation.&nbsp;</p>

Freileitungsmaste aus herkömmlichen Beton werden bereits heute in großer Zahl in Mittelspan-nungsnetzen eingesetzt. Im Bereich der Hochspannungsfreileitungen existieren bisher international nur wenige erste Freileitungen mit Masten aus herkömmlichen Beton. Um zukünftig Elektroenergie über große Entfernungen über Trassen mit geringen Flächenbedarf transportieren zu können, sind neue Hochspannungsfreileitungen in kompakter Bauweise notwendig. Um dieses Ziel zu erfüllen, sollen die Kompaktmaste aus ultra-hochfestem Beton (UHPC) hergestellt werden. Dafür ist eine neue Sorte von UHPC mit hoher Festigkeitsklasse zu entwickeln. Die mechanischen, elektrischen und thermischen Eigenschaften des neuen Betonmaterials waren zunächst unbekannt. Bisher gab es kaum Kenntnisse über die elektrischen und thermischen Belas-tungen, die auf die Betonmaste einer Freileitung in kompakter Bauweise einwirken. Ein Teilthema im interdisziplinären Forschungsprojekt „KoHöMaT“ (gefördert durch das Bundesmi-nisterium für Wirtschaft und Energie) war es, gemeinsam mit Forschungsinstituten (IMB, Fichtner, Lapp, Europoles, KIT, iBMB) die Materialparameter des neuen UHPC zu bestimmen. Den Einfluss der elektromagnetischen Belastungen auf die Lebensdauer und die Festigkeit des Ver-bundes aus Stahl und Beton habe ich untersucht. Aufgabe meiner Arbeit ist es auch, die elektrischen und thermischen Eigenschaften, wie die elektrische Leitfähigkeit, die elektrische Festigkeit, die Per-mittivität, den Verlustfaktor und die Wärmeleitfähigkeit experimentell zu bestimmen. Anhand der experimentellen Untersuchungen wurde der Versagensmechanismus des UHPC-Betons bei Span-nungsbelastung identifiziert. Die am Betonmast auftretenden elektrischen und thermischen Belas-tungen wurden mit Hilfe von verschiedenen FEM-Modellen berechnet und den gemessenen Fes-tigkeiten gegenübergestellt. Es wurde der Einfluss permanenter elektrischer Felder auf die mechanischen Eigenschaften des UHPC bestimmt. Hierfür wurde die Druckfestigkeit des Betons vor und nach Dauerversuchen bei verschiedenen Spannungsbelastung gemessen. Der Verbund zwischen Stahl und Beton wurde in Lastwechselversuchen thermisch hoch beansprucht und dessen mechanische Festigkeit vor und nach der thermischen Belastung bei Auszugsversuchen gemessen. Aufgrund der befürchtenden gesundheitlichen Risiken für Menschen und Tiere, sowie der gegen-seitigen Beeinflussung benachbarter elektronischer Systeme (EMV) dürfen die elektromagnetischen Felder von Freileitungen die jeweiligen maximal zulässigen Grenzwerte nicht überschreiten. Ich habe die Berechnungen der elektrischen und magnetischen Feldverteilung für die im Verbundvorhaben entwickelten Mastdesigns durchgeführt. Gemeinsam mit den Forschungsinstituten (Europoles, Fichtner, Lapp) wurden die Mastdesigns hinsichtlich der Feldverteilung optimiert. / The Overhead line towers made of conventional concrete are already used in large numbers in the medium voltage nowadays. So far, only a few towers of overhead transmission line made of con-ventional concrete which exists internationally in the area of high voltage. In order to be able to transmit electrical energy over long distances by routes of less floor space requirements, new high voltage overhead lines in compact construction are necessary. To achieve this goal, the compact towers have to be made of ultra-high-performance concrete (UHPC). Therefore, a new kind of UHPC with a high strength class has to be developed. For this kind of new concrete, the mechanical, electrical and thermal characteristics were unknown till now either, there was rare knowledge about the electric and thermal loads which have an effect on the concrete towers of an overhead line in compact construction method. The main purpose part of this interdisciplinary research project 'KoHöMaT “, which funded by the Federal Ministry for Economic Affairs and Energy), was to identify the material parameters of the new UHPC together with the following research institutes (IMB, Fichtner, Lapp, Europoles, KIT, iBMB). It was examined the influence of electromagnetic loads on the lifetime and its’ strength bond be-tween both of composite steel and concrete, also as my major involve was to determine the elec-trical and thermal properties experimentally, such as electrical conductivity, electrical strength, per-mittivity, dissipation factor and finally thermal conductivity. As a result, the failure mechanism of the UHPC under the electrical stresses has been identified then,the electrical and thermal loads on the concrete towers were calculated by using various FEM models accordingly, the measured values were used in the determination of electrical strength. All mentioned theoretical calculated parameters were compared with the real measured parameters. The influence of permanent electric fields on mechanical properties of the UHPC was determined as well. Mainly, the compressive strength of the concrete was measured before and after durability tests at different voltage loads. In addition, the composite (interface) between steel and concrete was thermal extremely loaded by alternating load tests. Its mechanical strength has been measured by pull-out tests before and after this thermal loads. Due to the fear of health risks for both humans and animals, as well as the mutual influence of neighboring electronic systems (EMV), the electromagnetic fields of open lines must not exceed the respective maximum permissible limit values. The calculations of the electrical and magnetic field distribution were carried out for the mast design developed in the composite project. Together with the other research institute (Europoles, Fichtner, Lapp). the tower designs were optimized with re-gard to the field distribution.