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Hydrogen peroxide sensing with prussian blue-based fiber-optic sensorsAkbari Khorami, Hamed 03 October 2016 (has links)
Hydrogen peroxide (H2O2) is extensively used in a broad range of industrial and medical applications, such as aseptic processing of food and pharmaceuticals, disinfection, water treatment plants, and decontamination of industrial effluents. H2O2 is believed to be responsible for chemical degradation of polymer membranes in Polymer-Electrolyte-Membrane (PEM) fuel cells. Therefore, a versatile H2O2 sensor that functions in different environments with different conditions is of practical importance in various fields. This dissertation presents the fabrication of a fiber-optic H2O2 sensing probe (optrode) and its H2O2 sensing behavior in different conditions.
An H2O2 optrode is fabricated using chemical deposition of Prussian blue (PB) onto the tip of a multimode optical fiber. Sensing tests are performed in aqueous solutions at a constant pH and different concentrations of H2O2. Sensing features of the optrode (i.e. repeatability, durability, and reproducibility) are assessed by performing multiple sensing tests with several optrodes. The results show the prepared optrode is able to detect concentrations of H2O2 in aqueous solutions at a constant pH of 4 and the optrode features a repeatable and durable response at this condition.
The functionality of optrodes at different pH values is further investigated by performing additional sensing experiments. These experiments are carried out in aqueous solutions with different concentrations of H2O2 at different pH values (i.e. pH 2-7). The sensor detects the presence of H2O2 at a range of pH values. Sensing behavior of optrodes toward detection and measurement of H2O2 concentrations is studied at the pH value corresponding to an operating PEM fuel cell (i.e. pH 2). The optrode is able to detect concentrations of H2O2 at this condition with a repeatable and durable response.
The stability of PB films, prepared through different conditions, is investigated to address the stability of optrodes at elevated temperatures. PB films are first deposited onto the glass slides through three different chemical processes, and then at different synthesis temperatures. The PB films are left in Phosphate-Buffer-Solutions (PBS) with pH 2 and at elevated temperatures for a day. Finally, PB films are characterized using Fourier transform infrared spectroscopy (FTIR) to analyze their stability following PBS processing at operating temperatures and pH value corresponding to an operating PEM fuel cell (i.e. 80 °C and pH 2). The results of these experiments illustrate the PB films prepared through the single-source precursor (SSP) technique and at synthesis temperatures above 60 °C remain stable after the PBS processing.
The proposed optrode shows reliable sensing behavior toward detection and measurement of H2O2 concentrations in aqueous solutions at different conditions. The prepared optrode has the potential for being developed and used in different industrial and medical fields, as well as an operating PEM fuel cell, to detect and measure H2O2 concentrations. / Graduate / 0794 / 0548 / 0485 / hakbarik@uvic.ca
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Nanoestruturação de filmes finos para utilização em eletrodos enzimáticos / Nanostructuration of thin films for applying in enzyme based biosensorsGonçales, Vinícius Romero 12 December 2011 (has links)
Os desafios atuais no desenvolvimento de biossensores abrangem diversos aspectos, tais como a necessidade de se aperfeiçoar a interface de contato entre o substrato e o material biológico, a eficiência de transdução do sinal químico em um sinal mensurável, o tempo de resposta, a compatibilidade dos biossensores com matrizes biológicas e a integração de diferentes elementos de reconhecimento biológico em um único dispositivo, visando a detecção de distintos analitos. Nesse contexto, o desenvolvimento da nanociência tem criado recursos bastante atraentes para otimizar os aspectos descritos acima. O presente trabalho apresenta, portanto, estudos realizados para a construção de mediadores nanoestruturados que possam operar de maneira mais eficiente que os correspondentes materiais maciços (sistemas não-nanoestruturados). Em uma das abordagens utilizadas, um mediador híbrido de hexacianoferrato de cobre/polipirrol (CuHCNFe/Ppy) teve suas propriedades eletroquímicas aliadas às propriedades morfológicas e eletrônicas de um feltro revestido com nanotubos de carbono do tipo \"cup-stacked\" (feltro/NTCCS) para o desenvolvimento de um sensor de H2O2. O feltro/NTCCS é uma malha hidrofílica condutora que permite uma dispersão bastante uniforme do mediador híbrido. Essa característica, aliada ao aumento da área eletroativa e à interação eletrônica existente entre o CuHCNFe/PPy e os nanotubos de carbono criaram uma plataforma favorável para a construção de um biossensor de glicose. Em uma segunda estratégia, esferas de poliestireno com diâmetros de 300, 460, 600 e 800 nm foram utilizadas como molde para a formação de filmes de CuHCNFe/PPy macroporosos. Os distintos mediadores foram aplicados na detecção de H2O2 com o intuito de se correlacionar a importância do tamanho do poro com o desempenho analítico obtido. Diferentemente do esperado, os mediadores maciços e porosos apresentaram desempenhos analíticos bastante similares, o que levou a uma consideração das propriedades termodinâmicas de superfícies curvas, da molhabilidade de materiais porosos e da influência da cinética eletroquímica na utilização de sistemas porosos. Tais plataformas também foram aplicadas com sucesso na construção de biossensores de glicose e de colina. Por fim, foi possível sintetizar mediadores nanoestruturados através da imobilização de camadas de azul da Prússia e de CuHCNFe dentro das cavidades de filmes de TiO2 mesoporosos (13, 20 e 40 nm de diâmetro). Os resultados obtidos demonstraram a possibilidade de se modular o desempenho dos sensores de H2O2 em função do diâmetro dos poros e da quantidade de mediador imobilizado. A união dos resultados analíticos obtidos com os dados de microscopia eletrônica de varredura possibilitou observar a importância do efeito de confinamento no desempenho dos mediadores. Além disso, dados espectroscópicos na região do visível foram fundamentais para relacionar a presença de defeitos estruturais com a reatividade do material. No fim, tais plataformas foram utilizadas para a formulação de biossensores de colina. / Nowadays, the challenges in the development of biosensors cover various aspects such as the need to improve the interface between the substrate and the biological material, the efficiency of the chemical signal transduction in a measurable one, the response time, the compatibility with biological matrices and the integration of different biological recognition elements in a single device, in order to perform detections of different analytes. In this context, the development of nanoscience has created very attractive features to optimize the aspects described above. Consequently, the present work studies the build up of nanostructured transducers that can operate more efficiently than the corresponding bulk materials (systems non-nanostructured). In one of the approaches used, a hybrid transducer consisting of copper hexacyanoferrate/polypyrrole (CuHCNFe/Ppy) had its electrochemical properties combined with the morphological and electronic properties of a felt decorated with cup-stacked type carbon nanotubes (felt/CSCNT) for development of a H2O2 sensor. Felt/CSCNT is a hydrophilic conductive mesh that allows a uniform dispersion of the hybrid transducer. This feature, coupled with the improvement of electroactive surface and with the electronic interaction among the CuHCNFe/Ppy and carbon nanotubes have created a favorable platform for the construction of a glucose biosensor. In a second strategy, polystyrene spheres with diameters of 300, 460, 600 and 800 nm were used as templates for the formation of macroporous CuHCNFe/Ppy films. The transducers were used to detect H2O2 in order to correlate the importance of pore size with the obtained analytical performance. Unlike expected, porous and bulk transducers presented very similar analytical performances, which led to a consideration of the thermodynamic properties of curved surfaces, the wettability of porous materials and the influence of electrochemical kinetics during the use of porous systems. Such platforms have also been successfully applied in the preparation of glucose and choline biosensors. Finally, it was possible to synthesize nanostructured transducers through the immobilization of Prussian blue layers and CuHCNFe inside the cavities of mesoporous TiO2 films (pore diameters of 13, 20 and 40 nm). The obtained results demonstrated the possibility of modulating the performance of H2O2 sensors according to the pore diameter and the amount of immobilized transducer. The union of the obtained analytical results with scanning electron microscopy data showed the importance of confinement effect on the transducers performances. In addition, spectroscopic data in the visible region were essential to correlate the presence of structural defects with the material reactivity. In the end, these platforms were used for the formulation of choline biosensors.
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Propriétés de commutation des analogues CoFe du bleu de Prusse : vers un contrôle de la position en énergie des états stable et métastable / Switching properties of CoFe Prussian blue analogues : towards a control of the position in terms of energy of the stable and metastable statesLejeune, Julien 26 June 2013 (has links)
Les composés à commutation électronique constituent une large famille de systèmes particulièrement prometteuse, notamment pour le stockage de l’information à l’échelle moléculaire. Parmi ces composés, les analogues du bleu de Prusse cobalt-fer (ABP AxCoFe) sont des polymères inorganiques formés d’enchaînements Co-N≡C-Fe pouvant présenter deux états électroniques CoII(HS)-N≡C-FeIII(BS) et CoIII(BS)-N≡C-FeII(BS) (HS : haut spin ; BS : bas spin) aux propriétés structurales et électroniques bien distinctes. La transition électronique entre ces deux états peut être contrôlée de manière réversible par une grande variété de paramètres chimique (insertion de cations alcalins) et physiques (température, pression, irradiation). Ces propriétés de photo-commutation sont particulièrement intéressantes pour le développement de mémoires optiques à l’échelle moléculaire.Afin de comprendre les propriétés électroniques des ABP AxCoFe, nous nous sommes intéressés à l’interaction entre les centres métalliques via le pont cyanure dans l’enchaînement Co-N≡C-Fe, aussi bien sur un plan expérimental (mise en œuvre de techniques d’analyse reposant sur l’utilisation du rayonnement synchrotron) que théorique (modélisation ab initio de type post-Hartree-Fock). Nous avons également étudié la nature de l’interaction, démontrée expérimentalement, entre les cations alcalins et le réseau bimétallique formé par les enchaînements Co-N≡C-Fe. Finalement, la pertinence du modèle à deux états, habituellement utilisé pour rendre compte des propriétés électroniques des systèmes commutables, est discutée, avec la mise en évidence de multistabilités au sein des ABP AxCoFe. Ce travail propose ainsi une étude la plus complète possible des phénomènes électroniques rencontrés dans ces systèmes. / Electronically switchable compounds constitute a wide family of very promising systems, especially in the field of data storage at a molecular scale. Amongst these compounds, cobalt-iron Prussian blue analogues (AxCoFe PBAs) are inorganic polymers based on Co-N≡C-Fe linkages that may exhibit two CoII(HS)-N≡C-FeIII(LS) and CoIII(LS)-N≡C-FeII(LS) (HS: high spin; LS: low spin) electronic states with very different structural and electronic properties. Electronic transition in between these two states can be reversibly controlled by a large variety of both chemical (insertion of alkali cations) and physical (temperature, pressure, irradiation) parameters. These photo switching properties are extremely appealing for the development of optical memory devices at the molecular scale.In order to understand the electronic properties of AxCoFe PBAs, the interaction occurring between the metallic centres through the cyanide bridge in the Co-N≡C-Fe linkages was investigated both at an experimental (use of synchrotron-radiation-based analytic techniques) and a theoretical (post-Hartree-Fock ab initio modelling) levels. The nature of the experimentally-demonstrated interaction between the alkali cations and the bimetallic network, made of the Co-N≡C-Fe linkages, was also studied. Finally, the relevance of the two-state model, usually invoked to account for the electronic properties of switchable systems, is discussed, as multistabilities are evidenced in PBAs. This work therefore offers study of the electronic phenomena occurring in such systems as comprehensive as possible.
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Composites "Oxydes nanostructurés-analogue du bleu de Prusse" : nouveau matériau pour le stockage de l'information / Composites "Nanostructured oxides of Prussian blue analogue" : new material for the information storage.Aouadi, Merwen 11 December 2012 (has links)
Les analogues du bleu de Prusse sont intéressants pour le stockage de l’information car ils présentent des propriétés de photo-commutation. Afin d’intégrer et d’exploiter ces propriétés photomagnétiques dans d’éventuelles applications, il est nécessaire de faire une étape de mise en forme. Cette dernière consiste à contrôler la taille, la forme ainsi que l’arrangement tridimensionnel des nanoparticules. Une stratégie consiste à élaborer des oxydes de silice nanostructurée par le procédé sol-gel. Une méthode a consisté faire précipiter les analogues du bleu de Prusse photomagnétiques dans la nanoporosité. Ainsi, il a fallu obtenir un monolithe ayant une unique organisation et non un mélange de phases. Il a été possible d’optimiser la méthode pour obtenir un monolithe hexagonal ayant des ions cobalt. Cette méthode a pu être étendue à différentes organisations : lamellaire, cubique, hexagonale, vermiculaire. Un traitement thermique permettant d’éliminer le copolymère afin de former le nanoréacteur. Une étude a permis de montrer que l’organisation etait conservée après un traitement thermique. Les ions cobalt subissaient une thermo hydrolyse durant le traitement thermique.Il a été possible de mettre en place une méthode d’imprégnation permettant d’obtenir différents nanocomposites CoFe et de contrôler la stœchiométrie des particules d’ABP confinées.Cette méthode a permis d’élaborer des nanocomposites CoFe sans cations alcalin et des nanocomposites CoFe contenant deux cations rubidium par maille. Les propriétés magnétiques ont permis de montrer l’effet de la mise en forme. De plus cette étude a permis de montrer que les propriétés de commuation sont concervées mêmes sur des nanoparticules de 5 nm. / The Prussian blue analogues (CoFe PBA) have attracted growing interest owing to the tunability of their magnetic properties by external stimuli that make them good candidates for future optical memories or switching devices.This study need a processing step to elaborate a nanocomposite material with full control on the stoichiometry, the size, the shape and the organisation of PBA particles.Our strategie consit to precipitate photomagnetic Prussian blue analogue in the nanoporosite. Our main idea is to use mesoporous silica monoliths as template for the precipitation of the PBA in order to control the size and the shape of the nanoparticles. A silica monolith contaigning cobalt ions in the hexogonal structuraction have been obtained. The method have been extended to another structuration ( wormlike, cubic and lamallar). A termal traitement at 500°C in air have been optimised to remove the copolymer and to obtain the nanoreacteur. During the termal traitement the cobalt ion change the symmetry. A thermo-hydrolysis of the cobalt drives to the formation of monomer tetrahedron of cobalt.The precipitation of Prussian Blue Analogues is realized by impregnation with a solution of potassium hexacyanoferrate (III). The parameters of the impregnation have to be finely controlled in order to obtain nanocrystals of Co-Fe wihout alkalin cations and nanocrystrals of CoFe with two cation rubidium. A photomagnetic nanocrystrals have been obtained.
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Das altpreußische Akzentsystem / Prūsų kalbos kirčiavimo sistema / The Old Prussian accentual systemRinkevičius, Vytautas 28 December 2009 (has links)
In der Dissertation wird das altpreußische Akzentsystem, das von der Orthographie der Sprachdenkmäler (zuallererst des 3. Katechismus) indirekt dargestellt wird, beschrieben. Das Ziel der Untersuchung ist eine ausführliche (insoweit das dürftig belegte Material eine Beurteilung zulässt) Rekonstruktion des synchronischen Zustands des apr. Akzentsystems und Feststellung möglicher Entwicklungstendenzen des Systems. Nach der kritischen Übersicht über alle bisherigen Theorien zur apr. Akzentologie und Akzentographie werden im ersten Schritt der Untersuchung die Prinzipien, nach denen betonte Silben der belegten Wörter anhand der Orthographie der Texte identifiziert werden können, bestimmt, auch wird die Realität der in früherer Literatur für das Altpreußische postulierten Akzentverschiebungsgesetze (z.B. Gesetz von Saussure-Fortunatov, Gesetz von Kortlandt u.a.) diskutiert. Die Hauptaspekte der nach den Prinzipien der morphologischen Akzentologiekonzeption vorgenommenen Untersuchung des Akzentsystems sind Feststellung der Akzenteigenschaften der Morpheme, welche die Akzentuierung flektierbarer Wörter bestimmen, Klassifizierung der belegten Wörter nach Akzentparadigmen und Analyse der Rolle des Akzents bei der Wortbildung. Das durch synchronische Untersuchung beschriebene System wird mit Systemen der verwandten Sprachen (zuallererst des Litauischen und der slavischen Sprachen) verglichen, ihre Übereinstimmungen werden konstatiert und Unterschiede werden erklärt. / Disertacijoje aprašoma prūsų kalbos kirčiavimo sistema, galimà atsekti iš šaltinių (visų pirma III prūsų kalbos katekizmo, teikiančio daugiausia akcentologijos duomenų) rašybos. Siekiama atkurti kiek įmanoma išsamesnį sinchroninį sistemos vaizdą ir nustatyti galimas diachronines jos raidos tendencijas. Kritiškai įvertinus visas iki šiol paskelbtas prūsų kalbos akcentologijos ir akcentografijos teorijas, pirmajame tyrimo etape apibrėžiami kirčiuoto skiemens nustatymo iš šaltinių rašybos principai, įvertinamas tokių mokslinėje literatūroje prūsų kalbai postuluojamų reiškinių kaip Saussure'o-Fortunatovo ar Kortlandto dėsniai realumas. Kirčiavimo sistemos analizėje, laikantis morfologinės akcentologijos principų, nustatomos kirčiavimą lemiančios paliudytų prūsų kalbos žodžių morfemų akcentinės savybės, žodžiai klasifikuojami į akcentines paradigmas, analizuojamas kirčio vaidmuo žodžių daryboje. Sinchroniniais metodais atkurta sistema nuosekliai lyginama su giminiškų kalbų (visų pirma lietuvių ir slavų) kirčiavimo sistemomis, konstatuojami jų sutapimai ir motyvuojami skirtumai. / The dissertation contains a description of the accentual system of Old Prussian as evidenced by the orthography of Prussian written monuments, particularly that of the Third Catechism (which abounds the most in accentological data). An attempt is made to reconstruct, as comprehensively as possible, the synchronic state of the accentual system in question, as well as to identify any possible trends in its diachronic development. At the first stage of research, upon a critical examination of all the theories dealing with Old Prussian accentology and accentography published to date, the methods of identifying the stressed syllable based on the orthography of the written monuments are outlined. The validity of Saussure-Fortunatov’s and Kortlandt’s laws, which have been postulated in the scholarly literature on Old Prussian, is subjected to a re-evaluation. Then, an analysis of the accentual system is undertaken, in adherence to the principles of morphological accentology, in order to determine the accentual properties of the Old Prussian morphemes conditioning the stress of the attested words, as well as to classify the words by accentual paradigm and to elucidate the role of stress in word-formation. This reconstructed synchronic system is then thoroughly confronted with those of the related languages (primarily Lithuanian and Slavic) to demonstrate the correspondences and to account for the discrepancies between them.
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Guerre défensive provoquée ou duel pour la prépondérance ? : nouveau regard sur les origines de la guerre franco-prussienne de 1870-71Lemieux, Carl Rudolf 08 1900 (has links)
La guerre franco-prussienne (ou franco-allemande) de 1870-71 fut un conflit majeur dont l’issue changea considérablement l’équilibre des puissances en Europe avec notamment l’émergence de l’Empire allemand. Pourtant, elle a été oubliée. Bien que depuis la fin du XIXe
siècle, elle fut largement traitée par l’historiographie, la question des responsabilités
relativement à son déclenchement demeure un sujet de débat. Tandis que certains historiens
estiment que cette guerre fut sciemment provoquée par Bismarck afin de parachever
l’unification allemande, d’autres croient que la responsabilité est partagée et que ce conflit était
tout simplement inévitable dans le contexte du refroidissement des rapports franco-allemands
depuis la défaite autrichienne de Königgrätz (Sadowa). Le présent mémoire entend se dissocier
de ces interprétations en jetant un nouveau regard sur le rôle joué par Bismarck lors des
« préliminaires » (Vorgeschichte) de 1870.
En s’appuyant sur des sources primaires ainsi que sur ce que les historiographies allemande,
française et anglo-saxonne nous apprennent, il sera démontré premièrement que la candidature
Hohenzollern pour le trône d’Espagne n’a pas été « fabriquée » volontairement par le chef de la
diplomatie prussienne afin de compléter l’unification allemande, mais qu’elle fut promue
d’abord et avant tout pour des considérations de prestige politique. Deuxièmement, la fameuse
dépêche d’Ems modifiée par Bismarck ne peut être considérée comme l’élément déclencheur de
ce conflit, car la décision d’aller en guerre fut prise à Paris avant que les effets de la dépêche ne
se fassent sentir. Enfin, par son besoin d’un succès politico-diplomatique qui aurait consolidé le
Second Empire en faisant oublier les reculades antérieures, par son refus de se satisfaire du
retrait de la candidature Hohenzollern et par les erreurs de sa politique étrangère en général, la
France a adopté une position belliqueuse et s’est retrouvée seule dans une guerre qu’elle n’avait
su ni prévenir, ni préparer. L’enjeu à Paris n’était finalement pas le règlement pacifique des
différends avec la Prusse, mais la pérennisation de la prépondérance française sur le continent
européen. / The Franco-Prussian War (or Franco-German War) of 1870-71 was a major conflict, where
the outcome dramatically changed the balance of power in Europe, including the emergence of
the German Empire. However, it has been forgotten. Although since the late nineteenth
century it was widely discussed by historians, the issue of liability with respect to its outbreak
remains a matter of debate. While some historians believe that this war was deliberately
provoked by Bismarck in order to complete the unification of Germany, others believe that the
responsibility was shared and that this conflict was simply inevitable in the context of the
worsening of Franco-German relations, since the Austrian defeat at Königgrätz (Sadowa), in
1866. This thesis aims to dissociate itself from these interpretations by providing new insight
regarding the role played by Bismarck during the “preliminaries” (Vorgeschichte) of 1870.
Through the use of primary sources and German, French and Anglo-Saxon historiography,
it will be shown first that the Hohenzollern candidature for the Spanish throne was not “made”
voluntarily by the chief of the Prussian diplomacy to complement the German unification, but
was promoted first and foremost for reasons of political prestige. Secondly, the famous Ems
telegram amended by Bismarck cannot be seen as the trigger of this conflict, as the decision to
go to war was taken in Paris before the negative effects of the message were felt. Finally,
through its need of a political and diplomatic success that would have consolidated the Second
Empire by forgetting earlier setbacks, through its refusal to show full satisfaction with the
withdrawal of the Hohenzollern candidature and through the misconduct of its foreign policy
in general, France adopted a bellicose position and found itself alone in a war it could neither
prevent nor prepare. The issue in Paris was ultimately not the peaceful settlement of disputes
with Prussia, but the perpetuation of French dominance on the European continent.
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Nanoestruturação de filmes finos para utilização em eletrodos enzimáticos / Nanostructuration of thin films for applying in enzyme based biosensorsVinícius Romero Gonçales 12 December 2011 (has links)
Os desafios atuais no desenvolvimento de biossensores abrangem diversos aspectos, tais como a necessidade de se aperfeiçoar a interface de contato entre o substrato e o material biológico, a eficiência de transdução do sinal químico em um sinal mensurável, o tempo de resposta, a compatibilidade dos biossensores com matrizes biológicas e a integração de diferentes elementos de reconhecimento biológico em um único dispositivo, visando a detecção de distintos analitos. Nesse contexto, o desenvolvimento da nanociência tem criado recursos bastante atraentes para otimizar os aspectos descritos acima. O presente trabalho apresenta, portanto, estudos realizados para a construção de mediadores nanoestruturados que possam operar de maneira mais eficiente que os correspondentes materiais maciços (sistemas não-nanoestruturados). Em uma das abordagens utilizadas, um mediador híbrido de hexacianoferrato de cobre/polipirrol (CuHCNFe/Ppy) teve suas propriedades eletroquímicas aliadas às propriedades morfológicas e eletrônicas de um feltro revestido com nanotubos de carbono do tipo \"cup-stacked\" (feltro/NTCCS) para o desenvolvimento de um sensor de H2O2. O feltro/NTCCS é uma malha hidrofílica condutora que permite uma dispersão bastante uniforme do mediador híbrido. Essa característica, aliada ao aumento da área eletroativa e à interação eletrônica existente entre o CuHCNFe/PPy e os nanotubos de carbono criaram uma plataforma favorável para a construção de um biossensor de glicose. Em uma segunda estratégia, esferas de poliestireno com diâmetros de 300, 460, 600 e 800 nm foram utilizadas como molde para a formação de filmes de CuHCNFe/PPy macroporosos. Os distintos mediadores foram aplicados na detecção de H2O2 com o intuito de se correlacionar a importância do tamanho do poro com o desempenho analítico obtido. Diferentemente do esperado, os mediadores maciços e porosos apresentaram desempenhos analíticos bastante similares, o que levou a uma consideração das propriedades termodinâmicas de superfícies curvas, da molhabilidade de materiais porosos e da influência da cinética eletroquímica na utilização de sistemas porosos. Tais plataformas também foram aplicadas com sucesso na construção de biossensores de glicose e de colina. Por fim, foi possível sintetizar mediadores nanoestruturados através da imobilização de camadas de azul da Prússia e de CuHCNFe dentro das cavidades de filmes de TiO2 mesoporosos (13, 20 e 40 nm de diâmetro). Os resultados obtidos demonstraram a possibilidade de se modular o desempenho dos sensores de H2O2 em função do diâmetro dos poros e da quantidade de mediador imobilizado. A união dos resultados analíticos obtidos com os dados de microscopia eletrônica de varredura possibilitou observar a importância do efeito de confinamento no desempenho dos mediadores. Além disso, dados espectroscópicos na região do visível foram fundamentais para relacionar a presença de defeitos estruturais com a reatividade do material. No fim, tais plataformas foram utilizadas para a formulação de biossensores de colina. / Nowadays, the challenges in the development of biosensors cover various aspects such as the need to improve the interface between the substrate and the biological material, the efficiency of the chemical signal transduction in a measurable one, the response time, the compatibility with biological matrices and the integration of different biological recognition elements in a single device, in order to perform detections of different analytes. In this context, the development of nanoscience has created very attractive features to optimize the aspects described above. Consequently, the present work studies the build up of nanostructured transducers that can operate more efficiently than the corresponding bulk materials (systems non-nanostructured). In one of the approaches used, a hybrid transducer consisting of copper hexacyanoferrate/polypyrrole (CuHCNFe/Ppy) had its electrochemical properties combined with the morphological and electronic properties of a felt decorated with cup-stacked type carbon nanotubes (felt/CSCNT) for development of a H2O2 sensor. Felt/CSCNT is a hydrophilic conductive mesh that allows a uniform dispersion of the hybrid transducer. This feature, coupled with the improvement of electroactive surface and with the electronic interaction among the CuHCNFe/Ppy and carbon nanotubes have created a favorable platform for the construction of a glucose biosensor. In a second strategy, polystyrene spheres with diameters of 300, 460, 600 and 800 nm were used as templates for the formation of macroporous CuHCNFe/Ppy films. The transducers were used to detect H2O2 in order to correlate the importance of pore size with the obtained analytical performance. Unlike expected, porous and bulk transducers presented very similar analytical performances, which led to a consideration of the thermodynamic properties of curved surfaces, the wettability of porous materials and the influence of electrochemical kinetics during the use of porous systems. Such platforms have also been successfully applied in the preparation of glucose and choline biosensors. Finally, it was possible to synthesize nanostructured transducers through the immobilization of Prussian blue layers and CuHCNFe inside the cavities of mesoporous TiO2 films (pore diameters of 13, 20 and 40 nm). The obtained results demonstrated the possibility of modulating the performance of H2O2 sensors according to the pore diameter and the amount of immobilized transducer. The union of the obtained analytical results with scanning electron microscopy data showed the importance of confinement effect on the transducers performances. In addition, spectroscopic data in the visible region were essential to correlate the presence of structural defects with the material reactivity. In the end, these platforms were used for the formulation of choline biosensors.
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Aristokraté a válka. O válce roku 1866 v dopisech a denících Karla, Rudolfa a Arnošta Chotka. Edice vybraných písemností. / Aristocrats and War. Letters and Diaries of Charles's, Rudolf's and Ernest's Chotek's about the War in the Year 1866. Edition of Selected Documents.Hanušová, Helena January 2016 (has links)
(in English): Aristocrats and war. Topic of this dissertation is the relation of nobility to the phenomenon of the war represented in this case by Czech nobility Chotek's family in the period Prussian- Austrian war in the year 1866 in our state territory. The basis for seeking of the answer were family correspondence and journals, which were created or have relation to the Prussian occupation in June and July of that particular year. According to the chosen standards documents, which are basis of adaptation of the edition, were selected. Two letters and two journals of members of the Chotek's family (Karel, Rudolf Karel and Arnošt) enriched with two public sources (Národní listy and Memorial Book of village Nové Dvory) provided ability of chronological comparison of the content of recorded events of these documents. The result of document analyses and comparison is, that counts Chotek's behavior and actions in this period showed no loyalty neither to the monarch nor patriotism but presented them as the large landowner, primarily interested in protection of their own property.
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Mechanistic Investigations of Metal-Metal Cooperativity in Dinickel Complexes and Iron/Cobalt Prussian Blue AnaloguesStevens, Hendrik 13 May 2021 (has links)
No description available.
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Maupertuis et ses critiques : textes et controverses / Maupertuis and his critics : texts and controversiesStorni, Marco 26 June 2018 (has links)
Si la pensée des lumières a parfois été célébrée par l’historiographie pour sa contribution significative au développement culturel et scientifique de la modernité, elle a le plus souvent été critiquée pour sa superficialité spéculative, ainsi que pour sa confiance aveugle dans les résultats des enquêtes scientifiques. La figure de Pierre-Louis Moreau de Maupertuis (1698-1759), à laquelle notre travail est consacré, rentre de plein droit dans ce cadre interprétatif : mentionné dans quelques récits historiques comme scientifique de premier plan, notamment pour sa contribution décisive à la diffusion des théories newtoniennes en France, il est relégué au second plan dans les travaux d’histoire de la philosophie et de l’épistémologie. L’un des objectifs principaux de notre travail est précisément de proposer une relecture de l’œuvre de Maupertuis qui emphatise l’intérêt spéculatif de ses doctrines, afin de montrer la place éminente qu’il occupe dans l’histoire de la pensée moderne. Nous nous pencherons ainsi sur quelques textes importants de Maupertuis, en soulignant le rôle capital qu’y jouent les questions épistémologiques et métaphysiques. L’analyse critique de la pensée scientifique et philosophique de Maupertuis n’est pourtant pas le seul aspect significatif de notre recherche : notre ambition est de proposer un récit plus vaste que la simple étude des travaux de Maupertuis, qui puisse contextualiser son œuvre dans les dynamiques de la République des Lettres au début du XVIIIe siècle. En ce sens, nous attribuons une importance toute particulière à l’étude des controverses de Maupertuis avec d’autres savants et philosophes. Il sera notamment question de deux controverses. La première, qui concerne la forme de la Terre, éclate au sein de l’Académie des Sciences de Paris entre 1733 et 1740. La deuxième, qui porte sur les monades et la philosophie wolffienne, a pour cadre l’Académie de Berlin entre 1746 et 1750. L’intérêt du travail sur les controverses de Maupertuis est double. Tout d’abord, il s’agit d’un aspect de la vie et de l’œuvre du savant que les commentateurs ont peu étudié : certes, il existe quelques études particulières sur les controverses maupertuisiennes, notamment de celle qui porte sur la figure de la Terre, mais la question n’est jamais thématisée de manière systématique dans les monographies publiées jusqu’ici. Ensuite, les controverses de Maupertuis nous paraissent intéressantes comme étude de cas pour comprendre le fonctionnement concret des controverses scientifiques et philosophiques. Nous ne prétendons évidemment pas présenter les conclusions que nous allons tirer de l’examen de ces controverses en tant que normes universelles pour l’étude de toute controverse scientifique ou philosophique du passé. Toutefois, comme les historiens travaillant sur les controverses privilégient souvent les scientifiques et les philosophes du XVIIe siècle, il nous semble intéressant de présenter une étude de cas provenant du XVIIIe siècle, qui appartient à un contexte intellectuel et social profondément différent de celui du siècle précédent. Nous pourrons ainsi apporter de nouveaux éléments de réflexion sur la nature du désaccord scientifique et philosophique, qui puissent intégrer et compléter les travaux existants. Ce que nous présentons ici, en définitive, n’est pas seulement une étude sur Maupertuis, mais un travail qui, à travers l’analyse de sa pensée et des controverses qu'elle a suscitées, vise à la reconstruction des rapports et des échanges qui constituent le réseau de la République des Lettres au début du XVIIIe siècle. L’œuvre de Maupertuis est ainsi envisagée comme un prisme, à travers lequel nous observons les lignes principales de développement de la science et de la philosophie de son époque. / Whereas historians have sometimes acknowledged the momentous contribution the Enlightenment provided to the cultural and scientific development of the modern world, more often they have criticized its speculative shallowness, and its overconfidence in the results of the scientific inquiry. The figure of Pierre-Louis Moreau de Maupertuis (1698-1759), holding a central place in our study, suffered the same fate as many other Enlightenment thinkers: mentioned in some historical narratives as a leading scientist and experimenter, most notably for the decisive contribution he gave to the circulation of Newtonian theories in France, he is relegated to the background in histories of modern philosophy and epistemology. One of the main objectives of the present research is to advance an interpretation of Maupertuis’ works which insists on the speculative depth of his doctrines, in order to display the preeminent place epistemological and metaphysical stakes occupy therein. The critical analysis of Maupertuis’ texts, however, is not the only important aspect of our study: we aim indeed at creating a wider narrative, which might contribute to clarify Maupertuis’ place within the intellectual network of the early 18th-century Republic of Letters. In this sense, we attribute a special importance to the study of Maupertuis’ controversies with other scientists and philosophers. The two controversies on which we concentrate are the controversy over the shape of the Earth, which took place at the Paris Academy of Sciences between 1733 and 1740, and the controversy over monads and Christian Wolff’s philosophy, taking place at the Berlin Academy of Sciences between 1746 and 1750. The interest of studying Maupertuis’ controversies is twofold. Firstly, it is an aspect of Maupertuis’ life and work commentators have overlooked: although there are a few essays dealing with Maupertuis’ controversies, which are for the most part focused on the question of shape of the Earth, monographs hitherto published do not discuss this aspect in detail. Secondly, Maupertuis’ controversies are an interesting case study to understand how scientific and philosophical controversies concretely work. We do not intend to claim that our study of Maupertuis’ controversies might function as a universally valid model for the study of each and every controversy in the history of science and philosophy. However, since historians studying controversies privilege case studies drawn from the 17th century, it seems useful to discuss an episode from another century, which belongs therefore to a different intellectual and social context. In this way, we will provide new elements of reflection on the nature of philosophical and scientific disagreement, which might integrate the existing literature on the subject. Ultimately, our study is not only a work on Maupertuis’ thought, but a survey that, through the analysis of Maupertuis’ texts and controversies, reconstructs the network of relations and exchanges which constitute the early 18th-century Republic of Letters. The work of Maupertuis functions therefore as a prism through which we observe the main lines of development of science and philosophy of his time.
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