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1
Sauvage, Xavier. "Transformations de phases induites par déformation plastique intense. Cas des aciers perlitiques tréfilés et des nanocomposites filamentaires Cu/Nb." Rouen, 2001. http://www.theses.fr/2001ROUES032.
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Les aciers perlitiques tréfilés et les nanocomposites filamentaires Cu/Nb sont élaborés par tréfilage à froid. La déformation plastique conduit à un allongement des grains le long de l'axe du fil et à une réduction importante de leurs dimensions dans la section transverse. Ainsi, les lamelles de cémentite des aciers perlitiques ne font plus que quelques nanomètres d'épaisseur et les fibres de niobium des composites Cu/Nb ont un diamètre moyen compris entre 10 et 60 nm. Ces nanostructures ont été caractérisées en microscopie ionique, sonde atomique, MET et METHR. Dans les aciers perlitiques, la dissolution partielle de la cémentite a pu être clairement mise à jour. Plus les lamelles sont fines, plus elles sont dissoutes. La dissolution est parfois totale et les zones transformées semblent alors évoluer vers une structure de type martensitique. La dissolution de la cémentite résulterait de l'accroissement considérable de la proportion d'interfaces. En considérant un effet de type Gibbs-Thomson, cette dissolution a pu être simulée. Toutefois, le taux de cémentite dissoute est sous-estimé car la modélisation de la cinétique ne prend pas en compte un terme de transport lié au champ de contraintes internes. Dans les nanocomposites filamentaires Cu/Nb, la déformation plastique n'affecte généralement pas la nature des différentes phases : le niobium et le cuivre restent purs. Toutefois, dans les zones où la taille de grains est inférieure à 15 nm, les analyses en sonde atomique révèlent une interdiffusion du cuivre et du niobium. Ces zones de mélange pourraient être amorphes comme le suggèrent nos observations en METHR. Cette amorphisation résulterait de l'accroissement considérable de l'énergie d'interface et de l'énergie élastique résultant des contraintes internes. La cinétique serait, quant à elle, favorisée par l'accroissement de la densité de lacunes au cours du tréfilage et par le champ de contraintes internes.
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Nilsonthi, Thanasak. "Caractérisation Physico-chimique et adhérence de couches d'oxydes thermiques sur des aciers recyclés." Phd thesis, Université de Grenoble, 2013. http://tel.archives-ouvertes.fr/tel-00947653.
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.L'objectif de cette étude était, en premier lieu, de mettre en place en Thaïlande un testd'adhésion par traction-écaillage sur une machine de traction classique (test" macroscopique "), de le comparer au test " microscopique " Grenoblois fonctionnant dansla chambre du MEB et de l'utiliser pour évaluer l'adhérence des calamines de process sur desaciers industriels. Deux paramètres ont été étudiés, la vitesse de déformation et la teneur desaciers en silicium. Il apparaît que l'écaillage des calamines au cours du test augmente quandaugmente la vitesse de déformation. Une vitesse de déformation élevée entraîne unedéformation au premier écaillage plus faible, donc une adhérence mesurée plus faible. Ceteffet est lié aux phénomènes de relaxation. On a pu alors montrer que la présence d'oxyde(s)contenant Si, situé(s) à l'interface avec le métal, augmentait l'adhérence. Les étudesd'oxydation dans la vapeur d'eau qui ont aussi été réalisées ont révélé que la présence desilicium réduisait la vitesse d'oxydation. En augmentant la teneur en Si, les couches defayalite et de wüstite s'épaississent ; par contre, les couches externes s'amincissent. Pour lesaciers contenant du cuivre, la vitesse d'oxydation est réduite quand la teneur en Cu estaugmentée. De la même façon, les couches internes sont plus épaisses et on observe uneaugmentation du nombre de précipités de Cu quand la teneur en cet élément augmente.
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Belfrouh, Abdeltif. "Influence des éléments d'alliage Mo, N, Cu et W sur le comportement électrochimique des aciers inoxydables de types 17Cr 13Ni en milieu acide sulfurique (2N) désaéré." Lyon 1, 1994. http://www.theses.fr/1994LYO10249.
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Ce travail est consacre a l'etude de l'influence des elements d'alliage, azote, molybdene, tungstene seuls ou associes, sur la tenue a la corrosion dans les domaines actif et passif des aciers inoxydables de type 17cr 13 ni. Les techniques electrochimiques, courbes courant-tension, courbes courant-temps et spectrometrie d'impedance ont ete systematiquement associees a des analyses de surface. On a montre d'une part l'effet nefaste de l'azote et du tungstene sur la corrosion active et d'autre part l'action benefique du molybdene seul ou associe a d'autres elements. A la tension d'abandon on a observe selon les elements d'addition soit un enrichissement soit un appauvrissement en chrome dans les couches superficielles. La presence d'azote dans les aciers accelere la formation des films passifs uniquement lorsque ceux-ci sont formes sur une surface activee cathodiquement. L'azote a de plus un effet favorable sur le vieillissement des films passifs. A la tension d'abandon, les mecanismes reactionnels sont sous controle diffusionnel pour les aciers allies au molybdene et au tungstene
4
Kozlova, Olga. "Brasage réactif Cu/acier inoxydable et Cu/alumine." Grenoble INPG, 2008. http://www.theses.fr/2008INPG0072.
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Dans ce travail nous étudions les aspects physicochimiques et mécaniques des joints brasés cuivre/acier inoxydable et cuivre/alumine. Dans la partie physicochimique nous étudions la mouillabilité, la réactivité aux interfaces et la microstructure des joints brasés. La partie mécanique porte sur les joints cuivre/alumine obtenus par brasage réactif et comprend des tests de traction et des essais de décollement par poinçon. A partir de résultats obtenus nous proposons des solutions optimales d'assemblage en terme de température, de durée de brasage et de composition des alliages de brasureIn this work we study the physico-chemical and mechanical aspects of the copper/stainless steel and copper/alumina brazed joints. In the physico-chemical part we study the wettability, the reactivity at the interfaces and the microstructure of the brazed joints. The mechanical part relates to the copper/alumina joints obtained by reactive brazing and includes tensile tests and shaft loaded blister tests. From the results we propose optimal solutions of assemblies in term of temperature, brazing time and composition of the braze
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Rimola, Gibert Albert. "Activation of amino acids and peptides by interaction of Cu(+) and Cu(2+) cations and aluminosilicate surfaces." Doctoral thesis, Universitat Autònoma de Barcelona, 2007. http://hdl.handle.net/10803/3244.
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Una molècula està activada quan, per acció d'un agent extern, mostra una reactivitat diferent que en el seu estat normal. Vies d'activació freqüents són per interacció amb cations metàl·lics, per absorció de radiació ionitzant o ultraviolada com també per adsorció en superfícies sòlides. Aquest treball tracta sobre l'activació de petites biomolècules, en concret d'aminoàcids i pèptids, per interacció amb cations de coure i aluminosilicats. Avui en dia es poden generar sistemes metall-lligand en fase gas i estudiar-ne la reactivitat induïda per la interacció amb els cations metàl·lics gràcies a les tècniques d'espectrometria de masses, les quals són rellevants en àrees com la proteòmica o la bioquímica. Aquesta tesi, doncs, es centra en el context de la química metal·loiònica en fase gas on es combinen càlculs teòrics amb experiments d'espectrometria de masses. No obstant, també tracta des d'un punt de vista mecanoquàntic l'activació de biomolècules per interacció amb superfícies de minerals degut a la seva importància en la química prebiòtica.A molecule is activated when, owing to an external agent, it displays different reactivity than in its normal state. The activation can be given by interaction with metal cations, by absorption of ionizing or UV radiation as well as by adsorption on solid surfaces. This work addresses the activation of small biomolecules, in particular amino acids and peptides, by the interaction with copper cations and aluminosilicates. Nowadays generating metal-ligand systems in the gas phase and studying the reactivity induced by the metal cations is feasible by means of recent mass spectrometry techniques, which are relevant in the areas of proteomics and biochemistry. This thesis, thus, is focused on the gas phase metal ion chemistry, in which theoretical calculations are combined with mass spectrometry experiments. Nevertheless, the activation of biomolecules by interaction with mineral surfaces has also been addressed from a quantum mechanic point of view, since its importance in the prebiotic chemistry.
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Madden, David Christopher. "Chirality and surface structure : an experimental study of amino acids on Cu{311}." Thesis, University of Cambridge, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648737.
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Little, Scott Alan. "Enhancement of Cu(In,Ga)Se2 Solar Cells and Materials via the Incorporation of Silver." University of Toledo / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1333734769.
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Kepenienė, Virginija. "Investigation of peculiarities of electroless copper plating systems using hydroxycarboxylic acids as Cu(II) ligands." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2012. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2012~D_20120601_102949-39519.
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Electroless metal coating technique is one of the elegant ways of metal coating by controlling the temperature and pH of the plating bath in which there is no usage of electric current. The industrial electroless copper plating solution containing formaldehyde as reducing agent are known from the middle of the last century and are widespread in the practice up to now. However many chemical compounds used in such kind technological processes are hazardous for total environment, therefore the efforts are made to displace those substances with less hazardous or purely harmless compounds. Generally two classes of chemical compounds were proposed as EDTA alternative, namely alditols (polyhydroxylic alcohols) and hydroxypolycarboxylic acids.
The aim of the work was to investigate peculiarities of formaldehyde containing alkaline electroless copper deposition systems using environment friendly hydroxycarboxylic acids as Cu(II) ligands.
Two new Cu(II) ligands, namely citric acid and D-isomer of tartaric acid, were applied for the systems of electroless copper deposition. The results of the investigations show that the ligands mentioned can be successful applied in the processes of electroless copper deposition using formaldehyde as reducing agent. Citric acid (2-hydroxypropane-1,2,3-tricarboxylic acid) and different isomers of tartaric acid (2,3-dihydroxybutanedioic acid), namely L- and D-tartrate, and their racemic mixture DL-tartrate, forming sufficiently stable complexes with... [to full text]Cheminio variavimo tirpalai bei cheminio variavimo procesai tiriami jau nuo XX a. vidurio iki šių dienų, ieškant vis efektyvesnių parametrų dangų funkcinėms bei dekoratyvinėms savybėms pagerinti. Pastaruoju metu vis didesnis dėmesys krypsta ne tik į nusodinamų dangų funkcionalumą, bet ir į ekologiškai nekenksmingus ar mažiau kenksmingus technologinius procesus, pzv., vykdoma ekologiškai nekenksmingų ligandų paieška. Kaip alternatyva šiuo metu siūlomos dvi cheminių junginių klasės t.y. alditoliai (polihodroksiliai alkoholiai) ir hidroksikarboksirūgštys. Pagrindinis darbo tikslas: ištirti cheminio variavimo sistemas ir jose vykstančius procesus, vario(II) jonų ligandais naudojant ekologiškai nekenksmingas citrinų ir vyno rūgštis. Cheminio variavimo sistemose panaudoti du nauji Cu(II) jonų ligandai t.y. citrinų rūgštis ir vyno rūgšties D-izomeras. Atliktų tyrimų duomenys rodo, kad minėti ligandai sėkmingai gali būti naudojami cheminio variavimo sistemose, kur reduktoriumi naudojamas formaldehidas. Nustatyta, kad 2-hidroksipropan-1,2,3-trikarboksirūgštis (citrinų rūgštis) ir 2,3-dihidroksibutano-1,4-dirūgštis (vyno rūgštis) šarminėje terpėje sudaro pakankamai patvarius kompleksus su vario(II) jonais ir yra tinkamas ligandas vario(II) kompleksinimui šarminiuose (pH > 12) cheminio variavimo tirpaluose. Ištirta vario(II)-citrato ir Cu(II)-D-, L- ir DL-tartratų kompleksų redukcija hidratuotu formaldehidu, apibūdintos gautosios vario dangos. Optimaliomis proceso vykdymo sąlygomis... [toliau žr. visą tekstą]
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Kepenienė, Virginija. "Cheminio variavimo sistemų, Cu(II) ligandais naudojant hidroksikarboksirūgštis, ypatumų tyrimas." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2012. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2012~D_20120601_102939-17894.
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Cheminio variavimo tirpalai bei cheminio variavimo procesai tiriami jau nuo XX a. vidurio iki šių dienų, ieškant vis efektyvesnių parametrų dangų funkcinėms bei dekoratyvinėms savybėms pagerinti. Pastaruoju metu vis didesnis dėmesys krypsta ne tik į nusodinamų dangų funkcionalumą, bet ir į ekologiškai nekenksmingus ar mažiau kenksmingus technologinius procesus, pzv., vykdoma ekologiškai nekenksmingų ligandų paieška. Kaip alternatyva šiuo metu siūlomos dvi cheminių junginių klasės t.y. alditoliai (polihodroksiliai alkoholiai) ir hidroksikarboksirūgštys.
Pagrindinis darbo tikslas: ištirti cheminio variavimo sistemas ir jose vykstančius procesus, vario(II) jonų ligandais naudojant ekologiškai nekenksmingas citrinų ir vyno rūgštis.
Cheminio variavimo sistemose panaudoti du nauji Cu(II) jonų ligandai t.y. citrinų rūgštis ir vyno rūgšties D-izomeras. Atliktų tyrimų duomenys rodo, kad minėti ligandai sėkmingai gali būti naudojami cheminio variavimo sistemose, kur reduktoriumi naudojamas formaldehidas. Nustatyta, kad 2-hidroksipropan-1,2,3-trikarboksirūgštis (citrinų rūgštis) ir 2,3-dihidroksibutano-1,4-dirūgštis (vyno rūgštis) šarminėje terpėje sudaro pakankamai patvarius kompleksus su vario(II) jonais ir yra tinkamas ligandas vario(II) kompleksinimui šarminiuose (pH > 12) cheminio variavimo tirpaluose. Ištirta vario(II)-citrato ir Cu(II)-D-, L- ir DL-tartratų kompleksų redukcija hidratuotu formaldehidu, apibūdintos gautosios vario dangos. Optimaliomis proceso vykdymo sąlygomis... [toliau žr. visą tekstą]Electroless metal coating technique is one of the elegant ways of metal coating by controlling the temperature and pH of the plating bath in which there is no usage of electric current. The industrial electroless copper plating solution containing formaldehyde as reducing agent are known from the middle of the last century and are widespread in the practice up to now. However many chemical compounds used in such kind technological processes are hazardous for total environment, therefore the efforts are made to displace those substances with less hazardous or purely harmless compounds. Generally two classes of chemical compounds were proposed as EDTA alternative, namely alditols (polyhydroxylic alcohols) and hydroxypolycarboxylic acids. The aim of the work was to investigate peculiarities of formaldehyde containing alkaline electroless copper deposition systems using environment friendly hydroxycarboxylic acids as Cu(II) ligands. Two new Cu(II) ligands, namely citric acid and D-isomer of tartaric acid, were applied for the systems of electroless copper deposition. The results of the investigations show that the ligands mentioned can be successful applied in the processes of electroless copper deposition using formaldehyde as reducing agent. Citric acid (2-hydroxypropane-1,2,3-tricarboxylic acid) and different isomers of tartaric acid (2,3-dihydroxybutanedioic acid), namely L- and D-tartrate, and their racemic mixture DL-tartrate, forming sufficiently stable complexes with... [to full text]
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Seymour, Jennifer Lynn. "Mass spectrometric and computational methods for the analysis of Cu(II)-2,2'-bipyridine amino acid complexes /." Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/8637.
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SILVA, ANDREA DE MORAES. "STUDY OF CU(II) E AL(III) COMPLEXES WITH PHOSPHOCREATINE (PCR), ADENOSINE 5´ TRIPHOSPHATE (ATP) AND SOME AMINO ACIDS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2003. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=4335@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROForam estudados os sistemas binários de complexos de Cu(II) e Al(III) formados com a fosfocreatina (PCr), o adenosina 5 trifosfato (ATP), a glicina (Gli), a serina (Ser), a tirosina (Tir) e a treonina (Tre) e os sistemas ternários (MLaLb) onde La foi o ATP ou a PCr e o Lb foi um dos quatro aminoácidos. O estudo foi realizado em solução aquosa através da técnica potenciométrica e das técnicas espectroscópicas ultravioleta-visível, Raman, RMN e RPE. As constantes de estabilidade foram determinadas pela potenciometria. Considerando L como um dos aminoácidos, foi observado que todos os complexos CuL são mais estáveis que os complexos AlL correspondentes. Este fato pode ser explicado pela grande afinidade entre o Cu(II) e o grupo amino. Por outro lado, os complexos binários formados com os fosfatos (ATP ou PCr) e o Al(III) apresentaram valores maiores de log b, do que os complexos de Cu(II) correspondentes. Este fato pode ser justificado pela grande afinidade do Al(III) com os átomos de oxigênio dos fosfatos. Pela mesma razão, todos os complexos ternários de Al(III) apresentaram-se mais estáveis do que os de Cu(II) correlacionados. Os valores das constantes de estabilidade dos complexos poderiam ser divididos em dois grupos: o dos complexos binários e o dos complexos ternários, com valores mais altos. Para os complexos de cobre, este comportamento foi confirmado pelo decréscimo dos valores dos comprimentos de onda máximos no espectro de absorção e no aumento no parâmetro Ao à medida que as constantes de estabilidade aumentaram. Os comprimentos de onda máximos dos complexos CuATPLb foram maiores que os dos complexos CuPCrLb, o que indica que o ATP deve coordenar com o Cu(II) através de dois átomos de oxigênio dos fosfatos e a PCr deve coordenar, nos complexos CuPCrLb, através de um átomo de oxigênio e um átomo de nitrogênio. O valor de D log K [log bCuLaLb) - (log bCuLa + log bCuLb)] mostrou que, quando La foi o ATP, os complexos ternários de Cu(II) e de Al(III) foram menos estáveis do que os seus binários respectivos, sugerindo não existir qualquer tipo de interação entre os ligantes. Aplicando o mesmo cálculo para os sistemas de Cu(II) onde La foi a PCr e Lb a serina ou a tirosina, o valor de D log K foi maior do que zero, indicando que estes ligantes favoreceram a formação de complexos ternários mais estáveis, o que pode ser justificado pela interação do grupo OH destes aminoácidos com o grupo livre (carboxilato ou fosfato) da PCr. Para todos os complexos AlPCrLb, onde Lb foi um dos quatro aminoácidos em estudo, os valores das constantes de estabilidade dos ternários foram maiores do que a soma das constantes dos seus binários. Este fato, não pode ser justificado pela interação do grupo OH dos aminoácidos com a PCr, já que a glicina não apresenta este grupo. Provavelmente, a interação ocorre através do oxigênio não coordenado do fosfato da PCr e do hidrogênio do grupo amino do aminoácido. O estudo do sistema Al(III):Ser pela espectroscopia Raman, mostrou que o complexo [Al(Ser)(H2O)4] 2+ é a espécie predominante e a serina atua como ligante bidentado (átomo de N do grupo amino e átomo de oxigênio do carboxilato). Este deve ser o comportamento de todos os complexos de Al(III) com os aminoácidos.
The binary systems of Cu(II) and Al(III) complexes with adenosine triphosphate (ATP), phosphocreatine (PCr), glycine (gly), serine (Ser), tyrosine (Tyr) and threonine (Thr) and the ternary systems where La was ATP or PCr and Lb was one of the four amino acids, were investigated. The study was performed in aqueous solution using potentiometry, ultraviolet visible, Raman, NMR and EPR spectroscopies. The stability constants of the complexes were determined by potentiometry. When L is one of the amino acids, it can be observed that all the CuL complexes are more stable than the correspondent AlL complexes. This can be explained by the greater affinity between the Cu(II) and the amino group. On the other hand, the binary complexes formed by one of the phosphates (ATP or PCr) and Al(III) have greater values of log b than the correspondent complexes of Cu(II). This can be explained by the greater affinity of Al(III) ion to the oxygen atoms of the phosphates. For this same reason, all the ternary complexes of Al(III) are more stable than the Cu(II) ones. The values of the stability constants of the complexes could be divided in two groups: one of the binary complexes and the second of the ternary complexes, with higher values. For the Cu(II) complexes this behavior was confirmed by the decreasing of the maximum wavelength in the absorption spectra and the increasing of the A0 parameter as the stability constants increase. The maximum wavelength of the CuATPLb complexes were greater than those of the CuPCrLb complexes and this means that ATP must be bound to Cu(II) ion through two oxygen atoms of the phosphates, whereas in CuPCrLb complexes, PCr is bound through one oxygen atom and one nitrogen atom and the amino acid is the same. Values of DlogK (logbCuLaLb - (logbCuLa+ logbCuLb) showed that when La was ATP, the ternary complexes of Cu(II) and Al(III) were less stable than the binary ones suggesting that it does not occur any interaction between the ligands in the ternary complexes. When La was PCr, the stability constants of the Cu(II) complexes where Lb was Ser or Tyr were greater. This showed that these ligands favored more stable ternary complexes and this must be due to the interaction of the OH group of these amino acids and the phosphate or carboxylate of PCr. For the AlPCrLb complexes, when Lb was one of the four amino acids, the stability constants of the complexes were greater. This shows that in this case, the interaction cannot be between the OH groups of the amino acid since glycine does not have any OH group. Probably the interaction occur through the non coordinated oxygen of the phosphate of PCr and the hydrogen of the amino group of the aminoacid. The study of the sistem Al(III):Ser by Raman spectroscopy, showed that [Al(Ser)(H2O)4]2+is the predominant species and that Ser acts as bidentate ligand (N atom of the amino group and O atom of the carboxylate). This must be the behavior of all the complexes of Al(III) and the amino acids.
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Clementino, Francisco das Chagas Ferreira. "Emprego de acidos hidroxamicos na extração dos ions Co (II), Cu (II), Fe (III), Ti (IV) e V(V) por solventes organicos e sua determinação por espectrofotometria de absorção atomica e na região do UV - visivel." [s.n.], 1987. http://repositorio.unicamp.br/jspui/handle/REPOSIP/248961.
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Orientador: Nivaldo BaccanTese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica
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Schneider, Thays. "Crescimento e teores de B, Cu, Mn, Fe e Zn em Pinus Taeda L,, como resultado da adubação e calagem sob a técnica da omissão de nutrientes." reponame:Repositório Institucional da UFPR, 2012. http://hdl.handle.net/1884/26281.
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Resumo: Os solos brasileiros, principalmente os do cerrado, são bastante intemperizados e com baixa fertilidade natural, sendo provavelmente essas características a responsável pelo aparecimento de deficiências nutricional nos plantios de Pinus taeda localizados no município de Jaguariaíva - PR. Com o objetivo de identificar o elemento mais limitante bem como, avaliar a influência da adubação e calagem nos teores Cu, Mn, Fe, Zn e B no solo, serapilheira e acículas, e quantificar o crescimento em altura e volume em função dos tratamentos, foi instalado em dois talhões de 5 anos e conduzido por dois anos, sob a técnica de diagnose por subtração. Foram concebidos os seguintes tratamentos: Completo (macronutrientes: N, P e K) + micronutrientes (Zn, B, Cu, Mo) + calagem (calcário dolomítico)]; menos macronutrientes; menos micronutrientes; menos K; menos Zn; menos calagem e testemunha. O efeito dos tratamentos foi avaliado pelos teores disponíveis de Cu, Zn, Mn e Fe por Mehlich I e B por água quente (nas camadas de 0-5, 5-10, 10-20, 20-40 e 40-60 cm), características da serapilheira como espessura, massa e teor de nutrientes, teor de nutrientes nas acículas da copa, e avaliação da altura e volume das árvores dominantes. Os solos apresentavam baixos valores de Cu, Mn e Zn extraído disponível, diferente do observado para Fe e B. O aumento de Zn e Cu disponíveis ocorreu na camada de 0-5 cm, enquanto o B afetou todas as profundidades avaliadas, indicando baixa e alta mobilidade dos elementos, respectivamente. A aplicação de Cu e Zn proporcionou aumento de dezenas até centenas de vezes no teor da serapilheira, principalmente na serapilheira mais velha. Os teores de B na acícula indicaram um rápido e expressivo aumento no teor tanto no primeiro e segundo lançamento, nos dois anos avaliados acompanhando os aumentos no solo. Baixos valores de Zn e Cu e alto de Mn foram observados na acícula. Em geral, a concentração de Fe e Mn nas acículas decresceu com uso de adubo e/ou calcário, para o segundo ano avaliado. Diferente do observado no solo, o uso de Zn e Cu não resultou em grande aumento no teor nas acículas, mantendo o teor em nível baixo para ambos os anos e solos. Ainda, a omissão dos mesmos e a testemunha, proporcionaram menores valores na acícula em algumas condições, não sendo consistente. Menor quantidade de serapilheira foi encontrada na testemunha sugerindo menor adição no período estudado. Menor incremento no volume de madeira foi observado com omissão de macronutrientes para área II em relação ao completo e tendência foi observado para testemunha nas duas áreas avaliadas.
Palavras - chave: Pinus, serapilheira, acidez do
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Lucas, Vaz José Luis. "Complexation du Cd(II) du Cu(II) et du Hg(II) par deux classes de polluants : dégradation photocatalysée des ligands en présence de TiO2." Lyon 1, 1997. http://www.theses.fr/1997LYO10252.
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Ce travail s'inscrit dans une demarche pluridisciplinaire concernant le projet d'amenagement d'un reseau d'evacuation d'eau residuaire, dans la region d'agadir. Dans la premiere partie, nous avons chiffre, a l'aide de techniques complementaires, telles que potentiometrie, polarographie, spectrophotometrie, les interactions binaires et ternaires entre le cadmium(ii), le cuivre(ii), le mercure(ii) et deux series de polluants : - huit homologues de l'uracile qui illustrent l'influence de la substitution de l'atome d'hydrogene sur les proprietes spectrales, acido-basiques et complexantes de cette classe de composes. En accord avec la plupart des travaux sur la chelation ternaire avec l'edta, nous observons que la stabilite des complexes ternaires est superieure a celle des complexes binaires correspondants. - quatre acides benzene-polycarboxyliques, consideres comme produits de degradation des acides humiques et fulviques. Dans la deuxieme partie, pour aborder l'aspect curatif, nous avons realise la degradation photocatalysee sur tio#2 des deux classes de polluants precedents. Nous etablissons un lien entre la nature du substituant en c#5 des homologues de l'uracile et leur degradabilite, d'une part, et l'effet nefaste des ions halogenures sur l'efficacite de l'oxydation photocatalytique, d'autre part. Le calcul des rendements quantiques montre que la photodegradation est moins efficace pour les acides benzene-polycarboxyliques. La photodegradation de melanges est abordee, par les systemes uracile - acide benzene-polycarboxylique. Dans tous les cas, un modele de type langmuir-hinshelwood permet de rendre compte de l'effet inhibiteur des acides benzene-polycarboxyliques sur la degradation de l'uracile. La conductimetrie et l'electrophorese capillaire permettent de suivre la mineralisation du carbone, de l'azote et de l'halogene, constituant chaque molecule.
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Barboiu, Mihai. "Etude de membranes hétéropolysiloxanes contenant de nouveaux précurseurs macrocycliques. Applications au transport facilité de Ag+/Cu+ et d'acides aminés (L-phénylalanine)." Montpellier 2, 1998. http://www.theses.fr/1998MON20002.
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Ce travail concerne la synthese, par le procede sol-gel, de membranes hybrides heteropolysiloxanes contenant des ether-couronnes fonctionnalises permettant le transport facilite des especes ioniques (ag#+/cu#2#+) ou moleculaires (acides amines). La synthese d'une nouvelle classe de macrocycles, derives du dibenzo 18-couronne-6, obtenus par une suite de reactions d'acylation et d'hydrazinolyse a ete effectuee. La meme sequence de reactions a ete realisee en utilisant comme substrat a acyler le diphenylether. Toutes les molecules macrocycliques et lineaires ont ete caracterisees par analyse elementaire, spectroscopie ir et rmn du #1h. Une double complexation des acides amines par les complexants macrocycliques synthetises a ete mise en evidence par la preparation d'une serie de 8 complexes supramoleculaires. Les materiaux membranaires elabores par voie sol-gel ont ete caracterises par analyse infrarouge, calorimetrie differentielle a balayage (dsc), mesures de la permeabilite a l'azote et microscopie electronique a balayage. Les conditions optimales d'utilisation de ces membranes dans la separation ag#+/cu#2#+, pour le transport facilite de la l-phenylalanine et pour la separation d'un melange d'acides amines ont ete etudiees. Les mecanismes de transport facilite bases sur des nouveaux principes de reconnaissance moleculaire dans un materiau solide dense sont presentes.
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Assmann, Tangriani Simioni. "Influencia da aplicação do calcario Irati (São Mateus do Sul - PR) nos teores de S, Cu, Fe, Mn e Zn no solo e na planta de milho (Zea mays L.)." reponame:Repositório Institucional da UFPR, 2012. http://hdl.handle.net/1884/27474.
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Este trabalho tem o objetivo de comparar a eficiência do calcário formação Irati, sobre o crescimento da planta de milho em relação a um calcário comercial, bem como verificar a contribuição diferenciada de doses crescentes dos dois corretivos quanto aos teores de sulfato, cobre, ferro, manganês e zinco, tanto para o solo como para a planta. Dois experimentos foram conduzidos em casa de vegetação no Setor de Ciências Agrárias da UFPR, tendo como substrato um Cambissolo TB, A proeminente, textura arenosa, proveniente de uma pastagem nativa localizada no município de Palmeira - PR. O primeiro experimento foi realizado em frascos, contendo 500 g, e o segundo conduzido em vasos. Os experimentos foram realizados independentemente, em delineamento inteiramente casualizado, com quatro repetições. Os tratamentos foram arranjados em ensaio fatorial 2x5, sendo 2 materiais corretivos (calcário comercial e calcário formação Irati) e 5 doses crescentes dos materiais corretivos, em t/ha equivalentes de CaCO3 (0,00; 0,75; 1,50; 3,00 e 6,00). No experimento em frascos, posteriormente à adição dos materiais corretivos, o solo foi umedecido, e as trocas gasosas foram realizadas através de aberturas diárias. Foram coletadas amostras de solo para determinação de sulfato aos: 1, 5, 15, 60, 90 e 280 dias de incubação. Incrementos de doses do calcário Irati e do tempo de incubação, resultaram em aumentos dos teores de sulfato no solo. No experimento conduzido em vasos, o qual recebeu previamente os tratamentos, foram efetuados dois cultivos consecutivos de milho (Híbrido AG 612). Embora doses crescentes de calcário Irati tenham provocado aumentos nos teores de sulfato no solo, atingindo o valor de 49ug/g, a mais alta dose e doses crescentes do outro material corretivo, pouco alteraram a quantidade do elemento no solo; tais diferenças não refletiram-0se sobre o teor de enxofre total das plantas. Da mesma forma, solos corrigidos com calcário Irati, apresentaram teores de cobre, ferro, manganês, extraídos do solo com DTPA-TEA, 5%, 10% e 9%, respectivamente, maiores do que aquele que recebeu calcário comercial, sem tal fato influenciar o conteúdo destes elementos na planta. Por outro lado, aumento de doses de calagem, provocaram decréscimos nos teores de manganês e ferro e não tiveram efeito sobre os teores de cobre no solo; na planta, ocorreram aumentos de concentração de ferro e cobre e diminuição dos teores de manganês. Na mais alta dose de calagem (6t/ha), as plantas cultivadas com calcário Irati, apresentaram teores de zinco, significativamente mais elevados do que aquelas cultivadas com calcário comercial, uma vez que o incremento desse material, , provocou uma diminuição da concentração do elemento na planta, enquanto que doses crescentes do calcário Irati, mantiveram os níveis de zinco constantes, evidenciando assim a disponibilidade às plantas do zinco existente no calcário Irati. Até a dose de 3t/ha, a qual elevou o solo a uma porcentagem de saturação de bases considerada adequada para o cultivo do milho, ambos os calcários comportaram-se de maneira equivalente quanto a produção de massa seca e diâmetro do colmo da planta de milho
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Say-Liang-Fat, Stéphanie. "Etude par spectroscopie électronique de la complexation de Al(III), Pb(II) et Cu(II) par des molécules modèles des substances humiques." Thesis, Lille 1, 2012. http://www.theses.fr/2012LIL10101/document.
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La complexation est le principal phénomène à l’origine de la rétention des métaux dans les sols. Il implique majoritairement les substances humiques (SH) dont les propriétés complexantes sont essentiellement dues à des groupes fonctionnels tels que les groupements phénoliques et carboxyliques. La compréhension des interactions métallo-humiques reste néanmoins limitée par la taille et la polyfonctionnalité des SH. L’utilisation de molécules modèles de faible poids moléculaire, présentant des sites de fixation similaires à ceux rencontrés dans les SH, permet de mieux appréhender le phénomène de complexation. Cette étude porte sur la complexation de trois cations métalliques, Al(III), Pb(II) et Cu(II), par des ligands présentant différents sites de fixation en compétition (catéchol, carboxylate, β-hydroxycétone). Dans une première partie, l’étude réalisée avec des dérivés de l’acide cinnamique, présentant des caractéristiques des SH (noyau aromatique, chaîne aliphatique), a permis de juger de l’influence de paramètres structuraux sur le phénomène de complexation (délocalisation électronique, substitution). Les stoechiométries et constantes de stabilité des complexes formés ont pu être déterminées. Dans une seconde partie, l’utilisation conjointe de la spectroscopie électronique et des calculs de chimie quantique a permis de caractériser des complexes formés avec des dihydroxyanthraquinones (site préférentiel, mode de fixation, sphère de coordination). Ce travail a permis de montrer l'utilité d'une telle approche couplant expériences et modélisation, et d'approfondir les connaissances disponibles sur les phénomènes de rétention des cations métalliques en milieu naturelComplexation is the main phenomenon responsible of metal retention in soils. Humic substances (HS) are the major components implied. Their complexing properties are due to functional groups such as phenolic and carboxylic functions. Nevertheless the study of metallo-humic interactions is limited by the size and polyfunctionality of HS. The use of low molecular sized model molecules, having similar fixation sites as those met in HS, enables to gain more insight into the complexation phenomenon. The fixation of three metal ions, Al(III), Pb(II) and Cu(II), by ligands presenting different complexing sites in competition (catechol, carboxylate, β-hydroxy-keto), was studied. The first part of this work focused on some cinnamic acid derivatives presenting the same characteristic features as HS (aromatic nucleus, aliphatic chain). The structural parameters effect (electronic delocalization, substitution) on complexation was studied. The stoichiometries and conditional stability constants of formed complexes have been determined. The second part combined electronic spectroscopy and quantum chemical calculations to characterize complexes formed with dihydroxyanthraquinones (preferential site, fixation mode, coordination sphere). This study showed the usefulness of an approach combining experiments and molecular modeling, and to increase available knowledge about metal ion retention in natural systems
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CABRAL, OTAVIO VERSIANE. "SYNTHESIS E CHARACTERIZATION OF COMPLEXES BETWEEN THE AMINO ACIDS SERINE, GLYCINE, ASPARTIC ACID, GUANIDINO ACETIC ACID AND METALS IONS CO(II), NI(II) AND CU(II)." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2005. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=6219@1.
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COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIORO presente trabalho representa um estudo analítico direcionado à síntese de complexos metálicos com aminoácidos no estado sólido. Foram sintetizados complexos binários e ternários dos aminoácidos: ácido aspártico, ácido guanidoacético, serina e glicina com os íons metálicos cobre (II), níquel (II) e cobalto (II). Embora muitos estudos destes complexos já tenham sido realizados em solução, verificou-se a existência de muitos questionamentos a respeito da química que rege o comportamento interativo dos ligantes com alguns metais de transição. A necessidade de controlar as condições de síntese tem direcionado o trabalho no sentido de criar uma metodologia específica para ser aplicada a esta importante classe de compostos: Aminoácidos. Assim, o presente trabalho tem como objetivo de desenvolver uma metodologia que permita sintetizar de forma sistemática diversos complexos de aminoácidos com metais de transição. A conjugação de gráficos dos diversos equilíbrios envolvidos nas sínteses permitiu que se estabelecesse uma metodologia gráfica para o controle de diversos parâmetros que interferem de forma significativa tanto no rendimento quanto na qualidade do produto final, reduzindo de forma sensível efeitos indesejáveis como a formação de hidróxidos e o excesso de água de hidratação presente. Para a caracterização dos compostos foram utilizadas diversas técnicas: espectroscopia de infravermelho, análise termogravimétrica, difração de raios X, análise elementar, espectrometria de absorção atômica e análise qualitativa. Paralelamente à técnica de síntese para obtenção de compostos na forma de pó, um controle mais adequado das condições de trabalho permitiu a obtenção de cristais. Estes compostos foram caracterizados por análise de raios X e espectroscopia de infravermelho. A conclusão deste trabalho mostrou que é de fundamental importância que se faça um rigoroso controle da composição dos produtos finais, com especial atenção para os compostos que apresentam alta capacidade de absorver água, uma vez que esta é uma variável que altera bastante o perfil do espectro de infravermelho e mascara os resultados das demais técnicas de caracterização. O sucesso na aplicação da metodologia gráfica na síntese de complexos produziu diversos compostos na forma de pó e outros na forma de cristais. Em alguns casos foram obtidos ligantes novos no processo de cristalização, sugerindo que haja interações entre os ligantes envolvidos.
An analytical study about the synthesis of metal complexes of amino acids in solid state was performed in this work. Binary and ternary complexes of the amino acids aspartic acid, guanidinoacetic acid, serine and glycine with the metal ions copper (II), nickel (II) and cobalt (II) were synthesized. Although several studies of these complexes in solution have been done before, many questions about the interactions between the ligands and some transition metals ions, still remained unanswered. The necessity of controlling the synthesis conditions directed this study toward the development of an specific methodology to be applied to this important class of compounds: the amino acids. With the aim of adding knowledge to the research about the synthesis of compounds in the solid state, a methodology was developed that allows the systematic synthesis of metal complexes with amino acids. The association of graphs of the several equilibria involved in the synthesis lead to the elaboration of a graphical methodology to control the various parameters that interfere in both yield and quality of the final product, reducing unwilling effects such as hydroxide formation and the presence of excess of water. For the characterization of the compounds, several techniques were used: infrared spectroscopy, thermogravimetric analysis, atomic absorption spectrometry and qualitative analysis. With a more accurate control of the work conditions, crystals were obtained. These compounds were characterized by X-ray diffraction and infrared spectroscopy. The results of this work showed that a rigorous control of the composition of the final products is of crucial importance, with special attention to the compounds that are able to absorb water, since this is a variable that affects the infrared spectrum and masks the results of the characterization techniques. The success of the application of the graphical methodology in the synthesis of complexes produced various compounds in the form of powder or crystal. In some cases new ligands were obtained during the crystallization process, suggesting that interactions between the ligands occurred.
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Gresser, Roland, Alexander Hoyer, Markus Hummert, Horst Hartmann, Karl Leo, and Moritz Riede. "Homoleptic Co(II), Ni(II), Cu(II), Zn(II) and Hg(II) complexes of bis-(phenyl)-diisoindol-aza-methene." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-138691.
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The synthesis of five homoleptic transition metal complexes of bis-(phenyl)-diisoindol-aza-methene is described together with the optical, electrochemical and thermal properties of these compounds. Additionally, crystal structures for the Co and the Zn complex are reportedDieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich
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Gresser, Roland, Alexander Hoyer, Markus Hummert, Horst Hartmann, Karl Leo, and Moritz Riede. "Homoleptic Co(II), Ni(II), Cu(II), Zn(II) and Hg(II) complexes of bis-(phenyl)-diisoindol-aza-methene." Royal Society of Chemistry, 2011. https://tud.qucosa.de/id/qucosa%3A27773.
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The synthesis of five homoleptic transition metal complexes of bis-(phenyl)-diisoindol-aza-methene is described together with the optical, electrochemical and thermal properties of these compounds. Additionally, crystal structures for the Co and the Zn complex are reported.Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
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Lassoued, Abdessalem. "Caractérisation de catalyseurs solides par fluorescence induite par laser." Paris 6, 2001. http://www.theses.fr/2001PA066447.
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Kayatekin, Can. "The Coupling Between Folding, Zinc Binding, and Disulfide Bond Status of Human Cu, Zn Superoxide Dismutase: A Dissertation." eScholarship@UMMS, 2010. https://escholarship.umassmed.edu/gsbs_diss/515.
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Cu, Zn superoxide dismutase (SOD1) is a dimeric, β-sandwich, metalloenzyme responsible for the dismutation of superoxide. Mutations covering nearly 50% of the amino acid sequence of SOD1 have been found to acquire a toxic gain-of-function leading to amyotrophic lateral sclerosis. A hallmark of this disease is the presence of insoluble aggregates containing SOD1 found in the brain and spinal cord. While it is unclear how these aggregates or smaller, precursor oligomeric species may be the source of the toxicity, mutations leading to increased populations of unstable, partially folded species along the folding pathway of SOD1 may be responsible for seeding and propagating aggregation.
In an effort to determine the responsible species, we have systematically characterized the stability and folding kinetics of five well studied ALS variants: A4V, L38V, G93A, L106V and S134N. The effect of the amino acid substitutions was determined on a variety of different constructs characterizing the various post-translational maturation steps of SOD1: folding, disulfide bond formation and Zn binding. Zn was found to bind progressively tighter along the folding pathway of SOD1, minimizing populations of monomeric species. In contrast, ALS variants were found to have the greatest perturbation in the equilibrium populations of the folded and unfolded state for the most immature, disulfide-reduced metal-free SOD1. In this species, at physiological temperature, four out of five ALS variants were >50% unfolded.
Finally the energetic barriers in the folding and unfolding reaction were studied to investigate the unusually slow folding of SOD1. These results reveal that both unfolding and refolding are dominated by enthalpic barriers which may be explained by the desolvation of the chain and provide insights into the role of sequence in governing the folding pathway and rate.
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Sarrazin-Baudoux, Christine. "Etude du mixage ionique dans un système à grande limite de solubilité : cas du Cuivre-Nickel, caractérisation de l'adhérence de ces revêtements sur substrat acier." Poitiers, 1987. http://www.theses.fr/1987POIT2305.
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Elaboration de la technique de melange ionique associant l'evaporation de couches minces successives et l'implantation ionique. Etude du melange ionique des multicouches cu-ni. Mise en evidence de deux phenomenes principaux de diffusion en fonction de la temperature. Analyse des phases formees lors du melange ionique. Application de la technique de melange ionique comme procede de depot
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Albourine, Abdallah. "Deux acides aminés constituants des graines de soja et de luzerne : la l-arginine et son analogue structural toxique la l-canavanine : identification par chromatographie liquide à haute performance : complexations binaire et ternaire avec Cu (II), Ni (II) et Zn (II)." Lyon 1, 1990. http://www.theses.fr/1990LYO10260.
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Au nombre des sources de proteines vegetales, on peut citer les graines de soja (alimentation humaine) et les graines de luzerne (alimentation animale) dont l'une des caracteristiques est de contenir a l'etat libre la 1-canavanine, analogue structural de la 1-arginine. Ces deux acides amines sont extraits directement sous leur forme non-proteinique. L'identification des produits et leur dosage son assures par chromatographie liquide a haute performance (clhp) et nous pouvons etablir un rapport de concentration 1-canavanine/1-arginine considere comme un critere de toxicite. Dans le but d'etablir une comparaison raisonnee entre ces deux acides amines, nous effectuons un examen des ligands et des complexes binaires et ternaires avec des metaux essentiels a la vie: cu(ii), ni(ii) et zn(ii). Les differentes constantes de stabilite ont ete determinees a 25#oc et a force ionique 0,1(nano#3). Cette technique est completee par des mesures spectrophotometriques, de dichroisme circulaire et de pouvoir rotatoire qui conduisent aux facteurs intensifs molaires correspondants. Pour cu#2#+ et zn#2#+, ces differentes mesures mettent en evidence deux complexes ml et ml#2, la 1-canavanine se comportant comme un ligand tridente et la 1-arginine comme un ligand bidente. Pour ni#2#+, nous sommes en presence de trois complexes nil, nil#2 et nil#3. La 1-canavanine prend un caractere bidente lors de la formation du complexe ni(can)#3. Afin de mieux cerner les groupemens chelatants, une approche theorique quantique des molecules a l'etat isole est engagee
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Lepinoux, Joël. "Organisation des structures de dislocations : étude en déformation cyclique et par simulation dynamique." Poitiers, 1987. http://www.theses.fr/1987POIT2015.
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Etude par microscopie electronique de la deformation cyclique des monocristaux de cuivre et des mono- et polycristaux d'acier ferritique. Mise au point d'un modele tenant compte des mecanismes locaux de multiplication et d'annihilation des dislocations. Simulation de l'arrangement dynamique de la structure des dislocations. Description de l'organisation de la microstructure en deformation monotone et cyclique, la propagation du glissement et divers aspects de la relation entre comportements microscopiques et macroscopiques de la plasticite
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Kozlova, Olga. "BRASAGE REACTIF CU/ACIER INOXYDABLE ET CU/ALUMINE." Phd thesis, 2008. http://tel.archives-ouvertes.fr/tel-00402086.
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Dans ce travail nous étudions les aspects physicochimiques et mécaniques des joints brasés cuivre/acier inoxydable et cuivre/alumine. Dans la partie physicochimique nous étudions la mouillabilité, la réactivité aux interfaces et la microstructure des joints brasés. La partie mécanique porte sur les joints cuivre/alumine obtenus par brasage réactif et comprend des tests de traction et des essais de décollement par poinçon. A partir de résultats obtenus nous proposons des solutions optimales d'assemblage en terme de température, de durée de brasage et de composition des alliages de brasure.
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Han, Sihui. "Le comportement d'hystérésis des solides et sa description par un schéma à mémoire discrète : le cas des aciers inoxydables." Habilitation à diriger des recherches, 1985. http://tel.archives-ouvertes.fr/tel-00319507.
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Étude du comportement d'un acier inoxydable 316L et d'un Inconel 718 dans le cadre d'un schéma thermomécanique à mémoire discrète constitué d'une équation multivoque, d'un critère d'inversion et d'un algorithme. Analyse détaillée des propriétés du comportement d'hystérésis pure. Etude des modules tangents aux courbes de charge. Mise en évidence de la restauration des propriétés du matériau après inversion et de la non-existence d'une discontinuité elastique-plastique dans le diagramme contrainte-déformation. Description de l'écrouissage en déformation à partir d'une analyse de la microstructure
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Li, Chih-Bin, and 李智斌. "Cu(OAc)2-Catalyzed Arylation of Carboxylic Acids by Arylboronic Acids." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/23185964247553065529.
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Su, Yu-Hwei, and 蘇育褘. "Activation of hydrogen peroxide by Cu(II)-amino acid complexes: effects of aldehydes and organic acids." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/07013760607251990282.
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碩士國立清華大學
生醫工程與環境科學系
96
Abstract Activation of hydrogen peroxide by Cu(II) complexes of native amino acids (L) has been studied by measuring the initial oxidation rate of quinaldine blue (QB) in aqueous phosphate media at 25°C. Hydrogen peroxide is an effective oxidant that can generate many kinds of reactive oxygen species to oxidize organic compounds. However, the mechanistic pathway that includes either hydroxyl radical or Cu(I)OOH● as the major reactive species is unclear. The formation rate of OH● can be observed by adding p-Nitrosodimethylaniline(PNDA). Methional is a copper- hydroperoxo complex (Cu(I)OOH●) scavenger that can inhibit the oxidation of organic compounds. From the experimental results, the major reactive species is identified that is Cu(I)OOH●. Based on the formation of Cu(I) and OH● by effect of methional, a possible mechanism is proposed. Moreover, aldyhydes and organic acids in Cu(II)- amino acid complexes system always inhibit the degradation of QB. Keywords : Hydrogen peroxide; Copper complex; Amino acid; Quinaldine blue; Methional; PNDA
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"Study of cu(ii) e al(iii) complexes with phosphocreatine (pcr), adenosine 5 triphosphate (atp) and some amino acids." Tese, MAXWELL, 2003. http://www.maxwell.lambda.ele.puc-rio.br/cgi-bin/db2www/PRG_0991.D2W/SHOW?Cont=4335:pt&Mat=&Sys=&Nr=&Fun=&CdLinPrg=pt.
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Speno, Henry Salvatore. "Identification of essential amino acids in the Cu(A) binding domain: Site directed mutagenesis in subunit II of cytochrome c oxidase of Saccharomyces cerevisiae." 1996. https://scholarworks.umass.edu/dissertations/AAI9619441.
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The Cu$\rm\sb{A}$ center, located in subunit II of cytochrome c oxidase, is the primary site for electron entry from cytochrome c. The recent crystal structure confirms this site to be a binuclear copper center with a dithiolate, dihistidyl coordination. A methionine and the carbonyl oxygen of Glu$\sp{198}$ are also ligands. To further characterize the structure and function of the Cu$\sb{A}$ center, site directed mutagenesis has been implemented in subunit II of S. cerevisiae. Substitutions of direct ligands to the Cu$\rm\sb{A}$ site result in loss of cellular respiration. Cytochrome a from cytochrome c oxidase is not detected in the visible absorption spectrum. Furthermore, subunit II does not accumulate to wild-type levels as observed by immunodetection. These results suggest that the enzyme is not assembling, most likely due to the disruption of copper binding, and that subunit II is being degraded. In contrast, substitutions to Glu$\sp{198},$ whose carbonyl oxygen is a ligand to one of the coppers, merely results in cells with reduced respiratory function. In an attempt to perturb the Cu$\rm\sb{A}$ site without disrupting protein stability, nearby amino acids were substituted. Asp$\sp{158}$ is known to hydrogen bond to the Cu$\rm\sb{A}$ ligand His$\sp{161}$, and Ser$\sp{197}$ is adjacent to the Cu$\rm\sb{A}$ ligand Cys$\sp{196}$. Substitutions at these positions result in reduced cellular respiration and may perturb the Cu$\rm\sb{A}$ site. Substitutions to conserved residues Gly$\sp{194}$ and Gly$\sp{201}$ result in a loss of cellular respiration and the underaccumulation of subunit II, while substitutions at other conserved positions have no observable effect on respiration. These results are discussed in relation to the homologous quinol oxidases and nitrous oxide reductases. To begin to characterize residues which may be involved in binding cytochrome c, substitutions were made to various conserved carboxylates which had been implicated in binding cytochrome c. The recent crystal structure demonstrates that Glu$\sp{198}$ and Asp$\sp{158}$ are not available for direct interaction with cytochrome c. However, the crystal structure does point to other conserved carboxylates. Asp$\sp{112}$ may be at the periphery of a cytochrome c binding site since replacement of this residue by Arg results in only a small decrease in cellular respiration.