Title: Solvent effects on ion pairing and photoionization in water Author: Mgr. et Ing. Eva Pluhařová Department: Physical and Macromoleculer Chemistry Advisor: Prof. Pavel Jungwirth, DSc., IOCB AS CR, v.v.i. Advisor's e-mail address: pavel.jungwirth@uochb.cas.cz Abstract: Various methods of theoretical chemistry, namely classical molecular dynamics simulations with empirical force fields, ab initio molecular dynamics, enhanced sampling methods, and ab initio calculations were used to provide new insight into ion pairing and photoionization in aqueous solutions. Systems mod- eling aqueous solutions of decreasing size were investigated by computational methods of increasing level of sophistication. In a classical molecular dynamics study of concentrated lithium salt solutions, the electronic continuum correction to account for polarization provided qualita- tive improvement over the conventional non-polarizable force fields and enabled molecular interpretation of neutron scattering measurements. The same model- ing approach was also successful in predicting the affinity of halide ions to the solution/oil interface. By combining ab initio molecular dynamics and potential of mean force cal- culations, we designed a reliable computational protocol for calculating the free energy profile for an ion pair...

This work introduces fundamental and alternative definition of Weil pairing and proves their equivalence. The alternative definition is more advantageous for the purpose of computing. We assume basic knowledge of elliptic curves in the affine sense. We explain the K-rational maps and its generalization at the point at infinity, rational map. The proof of equivalence of the two mentioned definitions is based upon the Generalized Weil Reciprocity, which uses a concept of local symbol. The text follows two articles from year 1988 and 1990 written by L. Charlap, D. Robbins a R. Coley, and corrects a certain imprecision in their presentation of the alternative definition. Powered by TCPDF (www.tcpdf.org)

Två vanliga räkneregler som elever lär sig om i matematikundervisningen är prioriteringsregeln och vänster-till-höger-principen. Tidigare forskning har dock visat att elever också använder påhittade regler som vanligtvis inte brukar användas inom matematiken. Syftet med den här studien är att undersöka dessa ”egenskapade” regler. Syftet uppnås genom att studera vad det är för mindre kända räkneregler som eleverna tillämpar samt om hur konsekventa eleverna är i sin användning av en typ av räkneregel.  I studien gjorde 55 elever i årskurs 5 ett arbetsblad bestående av fem numeriska uttryck. Av de 55 eleverna använde 16 av dem någon form av regel som gick ut på att tal i de numeriska uttrycken parades ihop. 13 av de här 16 eleverna blev intervjuade om hur de hade tänkt när de löste uppgifterna. Data för studien utgörs därför av elevernas arbetsblad såväl som transkriberingarna från intervjuerna. Studien visar tre olika slags ”regler” som eleverna använder, förutom de vanliga räknereglerna vänster-till-höger-principen och prioriteringsregeln. De tre räknereglerna bygger alla på att tal paras ihop på ett eller annat sätt. Trots att nästan ingen av de 13 eleverna hade fått undervisning om de vanliga räknereglerna, så använder eleverna egna regler som följer logiska strukturer. Dessutom visar studien att de flesta eleverna inte är speciellt konsekventa när det kommer till valet av regel. Många av eleverna väljer att använda olika slags räkneregler för att beräkna uttryck som är uppbyggda på nästan samma sätt. / Two common rules of arithmetic that students learn about in education are the order of operations and the counting from left to right. However, previous research has shown that students also use made-up rules which are not usually used in mathematics. The aim of this study is to investigate the rules of arithmetic created by the students themselves. The aim is achieved by examine what kind of less-known rules of arithmetic that students apply and also how consistent students are in their use of a type of rule.   In the study, 55 students did a worksheet consisting of five tasks. In total, 16 of the 55 students used some kind of rule where numbers in the numerical expressions were paired in some way. Furthermore, 13 of the 16 students were interviewed about their way of thinking when solving the tasks. The data therefore consists of the students’ worksheets and transcriptions from the interviews.  The study shows that, in addition to the usual conventions left-to-right and order of operations, students use three different kinds of rules of arithmetic. The three rules of arithmetic are based on the principle that numbers are paired in one way or another. Despite that almost none of the 13 students had been taught the conventional rules of arithmetic, most students use own rules that follow logical structures. In addition, the study shows that most students are not particularly consistent when it comes to choosing strategy. Many students choose to use different kind of rules of arithmetic when they are calculating expressions that are structured in almost the same way.

Tanto os motores turbo-jato quanto os turbo-fan, são os maiores responsáveis pela geração de ruído durante a decolagem, segmento de subida e de aceleração de uma aeronave. Devido a isto, o problema de ruído em jatos vem sendo intensamente investigado ao longo dos últimos anos. Já na fase do pouso, o slat é uma das fontes de ruído mais importantes. Para este caso, na maioria das aplicações práticas, existe o descolamento da camada limite no intradorso do slat a partir de onde se desenvolve uma camada de mistura. Ainda assim, existem inúmeros aspectos de tais escoamentos que precisam de investigação. Uma abordagem frequentemente feita para o estudo da instabilidade hidrodinâmica e ruído em jatos é o estudo de metade do jato. A estratégia consiste em estudar os fenômenos na camada de mistura, o que é uma aproximação razoável quando o jato tem diâmetro muito grande comparado à espessura da camada cisalhante que se desenvolve nas bordas do jato. Assim, alguns aspectos do ruído gerado pelos modos axi-simétricos de instabilidade são em grande parte reproduzidos. Um aspecto aparentemente jamais estudado antes é o efeito do emparelhamento de vórtices de diferentes geometrias na camada de mistura. Caso o efeito da modulação dos vórtices produzisse um padrão de ruído com características diferentes no emparelhamento, um controle ativo de escoamento por excitação periódica poderia ser usado para reduzir o ruído em jatos. O objetivo do presente trabalho é investigar tal efeito. A idéia é investigar este emparelhamento de vórtices na camada de mistura em desenvolvimento temporal bi-dimensional. Com isto foi possível visualizar um emparelhamento isolado de outros emparelhamentos e sem o efeito Doppler (presente na camada de mistura em desenvolvimento espacial). O método adotado foi a simulação numérica direta (DNS) das equações de Navier Stokes compressíveis na forma não-conservativa escritas na formulação característica. Os resultados mostram que a modulação dos vórtices não produz alteração significativa do ruído gerado no emparelhamento. / Turbo-fan and turbo-jet engines are the most important noise sources during the aircraft take off, climb and acceleration segments. Owing to this fact, the jet flow noise has been studied in the past years. For the landing stage, the slat is an important sound source. In this case, the slat leading edge frequently experiences a boundary layer deattachment causing the development of a mixing layer inside the slot. Nevertheless, there are many aspects of such phenomenon that have not been studied yet. Mixing layers constitutes an usual approach for jet flow instability in aeroacoustics studies. The stategy is to study the mixing layer in order to understand the jet-flow. This strategy becomes better as the ratio between the jet diameter and mixing layer thickness becomes larger. This approach is only reazonable for the jet flow axi-symetric unstable modes. The effect of vortex modulation on the vortex pairing sound production has not been found in the literature. If such effect could cause a significant change in the sound generation patterns, an active flow control system could be developed in order to enhance the jet noise performance. The purpose of the present work was to investigate such effect. It was also possible to observe a single vortex pairing inside a wide domain without the Doppler effect. The strategy was to study the vortex pairing in a bi-dimensional mixing layer under temporal development. The method used was the direct numerical simulation (DNS) of the compressible bidimensional (2D) Navier Stokes equations written in a nonconservative form of the characteristics formulation. The results showed that the vortex modulation did not produce a significant change on the vortex pairing sound.

Made available in DSpace on 2016-07-27T14:20:34Z (GMT). No. of bitstreams: 1 Marcileyde Tizo.pdf: 976236 bytes, checksum: f30ad0f2c7b47722cc770eb0e7b1b88f (MD5) Previous issue date: 2009-08-01 / It has been widely investigated how children learn to relate new words to objects or events. The present study, composed with three experiments, verified how the auditory-visual conditional relations are acquired by children in their first years of life. The first experiment was designed to verify if responses are controlled by: a) new pictures when new words are spoken; b) inclusion of the plural ending in a new word (lexical tip) when it is spoken in the presence of a comparative stimulus that is composed of several small and identical pictures; c) increasing choice opportunities. Ten children (ages from 2.5 to 4 years old) have participated. Results have shown that new stimuli have controlled the majority of responses despite of the lexical tip. Some responses of known stimuli to new spoken words have been observed in the first and second experiments. Experiment II has been conducted with six children (ages from 2.2 to 3 years old). Its main goal was to verify if responses would change by replacing known stimuli with other known pictures. Results were similar to the first experiment: children went on responding with known pictures to new spoken words. The third experiment has intended to check if responses are modified by repositioning the comparative stimuli. Four children aged from 2.7 to 4 years old have participated. Then, it was observed a significant reduction of responding with known pictures to new spoken words. In conclusion, new stimulus has controlled child behavior during all three experiments and lexical tips have not controlled the observed responses. / Como crianças aprendem a relacionar palavras novas a objetos ou eventos, tem sido amplamente estudado. O presente estudo teve o objetivo de verificar como ocorre a aquisição de relações condicionais auditivo-visuais por crianças nos primeiros anos de vida. Para isso, foram realizados três experimentos. O Experimento I teve como objetivos específicos: a) verificar se a presença de uma figura nova quando uma palavra nova é ditada controla o responder; b) verificar se o acréscimo da terminação de plural em uma palavra nova controla o responder quando ditado na presença de várias figuras de um mesmo estímulo novo agrupadas representando um único estímulo de comparação; c) verificar se aumentando as oportunidades de escolha o responder se modifica. Participaram desse experimento 10 crianças com 2 anos e meio a 4 anos de idade. Os resultados mostraram que o estímulo novo controlou o responder da maioria das crianças, independente da dica lexical. Um dado obtido no Experimento I e verificado no Experimento II foi a ocorrência de respostas para estímulos conhecidos quando uma palavra nova foi ditada. O Experimento II foi realizado com seis crianças que tinham 2 anos e dois meses a 3 anos e seis meses de idade. Esse estudo teve o objetivo de verificar se substituindo os estímulos conhecidos por outras figuras conhecidas, o responder seria modificado. Os resultados foram semelhantes ao Experimento I. Isto é, as crianças continuaram respondendo para as figuras conhecidas quando uma palavra nova foi ditada. Para continuar essa investigação, foi realizado o Experimento III, que verificou se, alterando a posição dos estímulos de comparação, modificaria o responder. O Experimento III foi realizado com quatro crianças com 2 anos e oito meses a 4 anos de idade. Observou-se nesse estudo a diminuição significativa de respostas para as figuras conhecidas quando uma palavra nova foi ditada. Concluiuse que a presença do estímulo novo controlou o comportamento das crianças durante os três experimentos realizados e que a dica lexical não exerceu controle sobre a resposta.

L’émission de paires de neutrons par les noyaux riches en neutrons 18C et 20O (isotones N = 12) est étudié par réactions de knock-out d’un nucléon des faisceaux secondaires 19N et 21O, peuplant ainsi des états non liés jusqu’à 15 MeV au-dessus de leur seuil d’émission deux neutrons. L’analyse des corrélations des triples coïncidences fragment+n+n montre que la décroissance 19N(−1p)→18C → 16C+n+n est clairement dominée par l’émission directe de paires. Les corrélations n-n, les plus grandes jamais observées, suggèrent la prédominance d’un coeur de 14C entouré de quatre neutrons arrangés en paires très corrélées. De plus, une importante compétition du mode de décroissance séquentiel est observée dans la décroissance 21O(−1n) → 20O → 18O+n+n, interprétée par la déformation causée par le knock-out d’un neutron très lié ayant pour effet de casser le cœur de 16O et ainsi de réduire le nombre de paires.De plus, les états non liés du 26F et 28F sont étudiés. Les deux systèmes étant peuplés par knock-out d’un nucléon du 27F dans le cas du 26F et du 29Ne ou du 29F pour 28F. Cinq états ont été observés pour 26F avec en particulier l’état de plus basse énergie (0.39 MeV) identifié comme l’état 3+ résultant du couplage d5/2 ⊗ d3/2 . Pour 28F, cinq états ont aussi été observés et l’état fondamental (200 keV) a été identifié comme étant de parité négative, plaçant ainsi 28F dans l’îlot d’inversion. / The emission of neutron pairs from the neutron-rich N = 12 isotones 18C and 20O has been studied by high-energy nucleon knockout from 19N and 21O secondary beams, populating unbound states of the two isotones up to 15 MeV above their two-neutron emission thresholds. The analysis of triple fragment-n-n correlations shows that the decay 19N(−1p) → 18C → 16C+n+n is clearly dominated by direct pair emission. The two-neutron correlation strength, the largest ever observed, suggests the predominance of a 14C core surrounded by four neutrons arranged in strongly correlated pairs. On the other hand, a significant competition of a sequential branch is found in the decay 21O(−1n) → 20O → 18O+n+n, attributed to its formation through the knockout of a deeply-bound neutron that breaks the 16O core and reduces the number of pairs.Moreover, unbound states in 26F and 28F have been studied. The two systems were probed using single-nucleon knockout reaction from secondary beams of 27F respectively in the case of 26F, and 29Ne and 29F for 28F. Five possible states have been identified in 26F, with in particular the lowest energy one (0.39 MeV) being identified as the 3+ state resulting from the d5/2 ⊗ d3/2 coupling. In the case of 28F, five unbound state have also been observed and in particular its ground state (200 keV) has been identified as a negative parity state, meaning that 28F is located inside the island of inversion.

NMR experiments performed under the effect of electric fields, either continuous or pulsed, can provide quantitative parameters related to ion association and ion transport in solution.  Electrophoretic NMR (eNMR) is based on a diffusion pulse-sequence with electric fields applied in the form of pulses. Magnetic field gradients enable the measurement of the electrophoretic mobility of charged species, a parameter that can be related to ionic association. The effective charge of the tetramethylammonium cation ion in water, dimethylsulphoxide (DMSO), acetonitrile, methanol and ethanol was estimated by eNMR and diffusion measurements and compared to the value predicted by the Debye-Hückel-Onsager limiting law. The difference between the predicted and measured effective charge was attributed to ion pairing which was found to be especially significant in ethanol. The association of a large set of cations to polyethylene oxide (PEO) in methanol, through the ion-dipole interaction, was quantified by eNMR. The trends found were in good agreement with the scarce data from other methods. Significant association was found for cations that have a surface charge density below a critical value. For short PEO chains, the charge per monomer was found to be significantly higher than for longer PEO chains when binding to the same cations. This was attributed to the high entropy cost required to rearrange a long chain in order to optimize the ion-dipole interactions with the cations. Moreover, it was suggested that short PEO chains may exhibit distinct binding modes in the presence of different cations, as supported by diffusion measurements, relaxation measurements and chemical shift data. The protonation state of a uranium (VI)-adenosine monophosphate (AMP) complex in aqueous solution was measured by eNMR in the alkaline pH range. The question whether or not specific oxygens in the ligand were protonated was resolved by considering the possible association of other species present in the solution to the complex. The methodology of eNMR was developed through the introduction of a new pulse-sequence which suppresses artifactual flow effects in highly conductive samples. In another experimental setup, using NMR imaging, a constant current was applied to a lithium ion (Li ion) battery model. Here, 7Li spin-echo imaging was used to probe the spin density in the electrolyte and thus visualize the development of Li+ concentration gradients. The Li+ transport number and salt diffusivity were obtained within an electrochemical transport model. The parameters obtained were in good agreement with data for similar electrolytes. The use of an alternative imaging method based on CTI (Constant Time Imaging) was explored and implemented. / <p>QC 20140825</p>

Cette thèse discute essentiellement sur le champ critique supérieur du supraconducteur ferromagnétique UCoGe. La conductivité thermique et d'autres méthodes expérimentales ont été utilisées pour confirmer les nombreux comportements particuliers de Hc2 dans UCoGe, précédemment observés dans des études de résistivité. Ces caractéristiques, y compris une anisotropie forte et des courbures anormales, ne peuvent pas être interprétées en termes de théories classiques pour Hc2. Au lieu de cela, un phénomène spécifique aux supraconducteurs ferromagnétiques - la dépendance en champ de l'interaction d'appariement doit être considéré. Nous montrons que cet effet peut être analysé de façon cohérente avec des propriétés de la phase normales et peut être aussi comparé quantitativement avec une théorie existante. Ceci conduit à une clarification nette pour le cas de H//c dans UCoGe, et explique en même temps le comportement différent de Hc2 dans UCoGe et URhGe. Ces résultats soutiennent fortement l'origine magnétique de la supraconductivité dans ces systèmes. Pour H//b, nous montrons que certaines observations expérimentales convergentes suggèrent un possible changement d'état supraconducteur induit par le champ magnétique transversal dans UCoGe. Indépendamment du reste de l'étude, le dernier chapitre présente quelques résultats expérimentaux sur la phase normale de UCoGe et sur l'autre système de fermions lourds UBe13. / This thesis mainly discuss the upper critical field of the ferromagnetic superconductor UCoGe.Thermal conductivity and other experimental methods have been used to confirm the numerous particularbehaviors of Hc2 in UCoGe, previously observed in resistivity studies. These features, including the stronganisotropy and the anomalous curvatures, cannot be interpreted in terms of classical theories for Hc2.Instead, a phenomenon specific to the ferromagnetic superconductors - the field dependence of the pairinginteraction, needs to be considered. We show that this effect can be consistently analyzed with normalphase properties, and is quantitatively compared with existing theory. This leads to a net clarificationfor the case of H//c in UCoGe, and at the same timeexplains the different behavior of Hc2 in UCoGe and URhGe. These resultsstrongly support the magnetic origin of superconductivity in these systems. For H//b, we showconvergent experimental observations that suggest a possible change of the superconducting state inducedby the transverse magnetic field in UCoGe. Independent from the rest of the study, the last chapter presents someexperimental results on the normal phase of UCoGe and on the other heavy-fermion system UBe13.

Les catécholamines et les indolamines font partie de la famille des neurotransmetteurs. Un déséquilibre dans leur concentration peut être associé à différentes maladies telles les maladies de Parkinson et Alzheimer, la dépression ou la schizophrénie. C’est pourquoi le développement de méthodes de dosage spécifiques et très sensibles du fait de leurs très faibles teneurs dans les fluides biologiques est nécessaire. Dans un premier temps nous avons développé une méthode chromatographique en appariement d’ions (IP-LC) utilisant des colonnes C18 de nouvelle génération (monolithique et « fused core ») et l’acide nonafluoropentanoïque, comme agent d’appariement d’ions volatil. Cette méthode est compatible avec une détection SM en mode d’ionisation positive. Dans un deuxième temps, différents systèmes en mode HILIC ont été évalués. Le choix raisonné de la phase stationnaire offrant la meilleure séparation du mélange de catécholamines a pu être réalisé après avoir testé l’influence sur la séparation des différents groupements fonctionnels disponibles : groupement soit neutre (greffage diol, amide, ou cyano), soit positivement chargé (greffage amino ou triazole) soit négativement chargé (silice vierge avec particules totalement poreuses ou partiellement poreuses « fused core ») ou zwitterionique (greffage sulfobetaïne). La méthode HILIC présente l’avantage d’être compatible aussi bien avec une détection SM en mode d’ionisation positive que négative. Les deux méthodes (IP-LC et HILIC) ont été comparées en termes de résolution, efficacité et limites de détection (LOD), linéarité et répétabilité. Les LODs obtenues sont comprises entre 1 et 100 ng.mL-1. Pour pouvoir doser des teneurs plus faibles, une méthode de pré-concentration de l’échantillon a été développée en associant 2 supports différents (Oasis HLB et PGC). La méthode optimisée SPE-CPL-MS/MS a été enfin appliquée à un extrait de cerveau de mouton. / As neurotransmitters, catecholamines play an important role in the control and regulation of numerous brain functions. They are also believed to be implicated in different neurodegenerative disorders. First an ion pairing chromatography method using nonafluoropentanoic acid as volatile ion paring agent was developed on the new generation of C18 columns (monolith and fused core). This method is compatible with MS detection in positive ionization mode. Secondly an HILIC method was optimized using different commercially available HILIC supports, they can be classified as follows: neutral (diol, amide, and cyano bounded), positively charged (amino, triazole bounded), negatively charged (bare silica as wholly porous particles or fused core particles columns) and zwitterionic (sulfobetaine bounded). Our studies lead us to a better understanding of the HILIC retention mechanism and also to the selection of the most appropriated column for catecholamine analysis. Only the HILIC system was compatible with both positive and negative ionization modes. The two chromatographic systems were then compared in terms of resolution, efficiency, detection and quantification limits (LOD/LOQ), calibration linearity and repeatability. The LODs obtained were in the range of 1-100 ng.mL-1. A simple pre-concentration method using Oasis HLB and PGC solid phase extraction cartridges has been optimized in order to enhance the LODs. Finally the optimized SPE-LC-MS/MS method has been applied to the identification of these compounds present in brain extracts.

Made available in DSpace on 2014-12-17T15:14:53Z (GMT). No. of bitstreams: 1 RonivonLE_DISSERT.pdf: 2244591 bytes, checksum: e86660db1b3ec37036777503cc5e8a0d (MD5) Previous issue date: 2010-12-20 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / In this work we investigate the effect of a BCS-type pairing term for free spinless fermions, with a propensity to form a condensate of pairs in a 1+1 dimension. Using the of bosonization technique we explore the possible condition of existence of quasiparticles in a superconducting state. Although there is no spontaneous breaking of chiral symmetry the propagator of one-particle fermion is massive and, in fact, resembles the one-particle Green s function of conventional quasiparticles / Neste trabalho investigamos o efeito de um termo de emparelhamento do tipo BCS para f?rmions livres sem spins, com propens?o a formar um condensado de pares em uma dimens?o 1+1. Utilizando a t?cnica de bosoniza??o vamos explorar a poss?vel condi??o de exist?ncia de quasipart?culas em um estado supercondutor. Embora n?o haja nenhuma quebra espont?nea de simetria quiral o propagador de 1-part?cula fermi?nica ? massivo e de fato assemelha-se a fun??o de Green de 1-part?cula de uma quasipart?cula convencional