Дисертації з теми "Quadrupolar phase"
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Sales, Nilva Lúcia Lombardi. "Interação quadrupolar em compostos cúbicos à base de praseodímeo." Universidade de São Paulo, 2001. http://www.teses.usp.br/teses/disponiveis/76/76132/tde-24062008-085924/.
Повний текст джерелаThis work considers the presence of interactions in rare earth intermetallic compounds with cubic symmetry. In chapter 2 the crystalline electric field is taken into account and in chapter 3 an RKKY interaction between nearest neighbours is introduced in order to obtain magnetic order in the crystal. These interactions alone are sufficient to explain magnetic behavior of several based Pr compounds, with PrMg2 an exception for what a quadrupolar interaction has been proposed in the literature; the addition of this interaction constitutes the principal goal of this work and is developed in chapter 4. The temperature dependence of the magnetic- and quadrupolar-order parameters is studied under the mean-field approximation. The stability of those parameters are analyzed by means of an exact mean-field free energy (as opposed of a Landau expansion, an approximation common in the literature). A phase diagram is obtained relating the magnetic and quadrupolar couplings with the nature of the ground state mean-field Hamiltonian and the kind of the phase transitions (first or second). It is showed that the PrMg2 undergoes a second order phase transition, as observed experimentally, after an inclusion of a Heisenberg like antiferroquadrupolar coupling. The numerical calculations were performed using the Maple software and the codes are listed in the appendix.
Bristow, Anthony Walter Thomas. "Laser desorption and high resolution studies in quadrupole ion trap mass spectrometry." Thesis, Nottingham Trent University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336973.
Повний текст джерелаMalik, A. Q. "Kinetic studies of gas phase cations by charge-exchange techniques in a two-quadrupole tandem mass spectrometer." Thesis, University of Essex, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372588.
Повний текст джерелаPowoski, Robert A. "Molecular Structure Analyses of Asymmetric Hydrocarbon Liquid Compounds in the Gas Phase Using Chirped-pulse Fourier Transform Microwave Spectroscopy: Acyl Chlorides and Perfluorinated Acyl Chlorides." Thesis, University of North Texas, 2011. https://digital.library.unt.edu/ark:/67531/metadc103374/.
Повний текст джерелаHall, Robin Gibson. "The development of a quinquaquadrupole mass spectrometer : the study of ion-molecule reactions in the gas phase using multiple quadrupole instruments." Thesis, University of St Andrews, 1991. http://hdl.handle.net/10023/15506.
Повний текст джерелаHall, Bradley John. "Development of solid phase microextraction (SPME) and matrix assisted laser desorption ionization (MALDI) with quadrupole ion trap mass spectrometry for analytical applications /." Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.
Повний текст джерелаPerumal, Karthick. "Epitaxial growth of Ge-Sb-Te based phase change materials." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2013. http://dx.doi.org/10.18452/16815.
Повний текст джерелаGe-Sb-Te based phase change materials are considered as a prime candidate for optical and electrical data storage applications. With the application of an optical or electrical pulse, they can be reversibly switched between amorphous and crystalline state, thereby exhibiting large optical and electrical contrast between the two phases, which are then stored as information in the form of binary digits. Single crystalline growth is interesting from both the academic and industrial perspective, as ordered Ge-Sb-Te based metamaterials are known to exhibit switching at reduced energies. The present study deals with the epitaxial growth and analysis of Ge-Sb-Te based thin films. The first part of the thesis deals with the epitaxial growth of GeTe. Thin films of GeTe were grown on highly mismatched Si(111) and (001) substrates. On both the substrate orientations the film grows along [111] direction with an amorphous-to-crystalline transition observed during the initial stages of growth. The amorphous-to-crystalline transition was studied in-vivo using azimuthal reflection high-energy electron diffraction scans and grazing incidence x-ray diffraction. In the second part of the thesis epitaxy and characterization of Sb2Te3 thin films are presented. The third part of the thesis deals with the epitaxy of ternary Ge-Sb-Te alloys. The composition of the films are shown to be highly dependent on growth temperatures and vary along the pseudobinary line from Sb2Te3 to GeTe with increase in growth temperatures. A line-of-sight quadrupole mass spectrometer was used to reliably control the GeSbTe growth temperature. Growth was performed at different Ge, Sb, Te fluxes to study the compositional variation of the films. Incommensurate peaks are observed along the [111] direction by x-ray diffraction. The possibility of superstructural vacancy ordering along the [111] direction is discussed.
Robb, Damon Bradley. "Studies of the effects of the amplitude and phase of the RF potential on the trapping process in laser desorption quadrupole ion trap mass spectrometry." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ34617.pdf.
Повний текст джерелаChristides, Achille. "Spectrométrie pulsée de R. Q. N. Et contribution à l'étude de la phase incommensurable de β-ThBr ₄". Paris 11, 1987. http://www.theses.fr/1987PA112068.
Повний текст джерелаWe describe the realization of the radio-frequency sections of a pulsed and computerized N. Q. R. Spectrometer, the design of which is derived from a system existing at the Laboratory. The performances were improved and the design made with a view to increase the versatility of the N. Q. R. Research Group facilities. The all solid-state spectrometer can be operated from a few hundred hertz up to 60 MHz. Circuits are wide-band except for the tank circuit and a tunable pass-band circuit provided to reduce the amplified noise level; as a result adjustments when operating the system are minimized and phase shift problems are eliminated. The rejection ratio of the analogic gate is increased and still 60 db at 80 MHz. The transmitting power stage, also transistorized, can deliver one hundred watts up to 60 MHz time 15 µs. The receiver pass-band is 80 MHz and its recovery when the high-Q tank circuit is not connected. The spectrometer has been used for investigating the incommensurate phase of ß-ThBr4 below 96 K. As compared with previous measurements made with a SRO spectrometer of poor re solution as line shape studies are considered, this series of investigations brings new pieces of information about the actual shape of the broad bromine N. Q. R. Line observed in the incommensurate phase below 96 K. In the range of temperature investigated so far (77-96 K), the line remains quite symmetrical with respect to its center frequency suggesting that the modulation is of the sine plane wave type. Investigation of the relaxation time, T1, shows a strong relaxation near the phase transition temperature quite probably related to the soft mode condensation at the transition temperature
Bonnisseau, Dominique. "Etude des structures magnétiques de composés de neptunium (NpAs, NpSb, NpSe et NpRu2Si2)." Grenoble 1, 1987. http://www.theses.fr/1987GRE10144.
Повний текст джерелаMerloti, Karina. "Condensat de Bose-Einstein dans un piège habillé : modes collectifs d'un superfluide en dimension deux." Phd thesis, Université Paris-Nord - Paris XIII, 2013. http://tel.archives-ouvertes.fr/tel-00949914.
Повний текст джерелаLabouze, Xavier. "Etude par résonances nucléaires des propriétés magnétiques des cuprates supraconducteurs dans leurs phases isolantes." Grenoble 1, 1994. http://www.theses.fr/1994GRE10042.
Повний текст джерелаManallah, Bouzid. "Observation de raies nouvelles dans le spectre de RQN de l'azote-14 dans quelques dérivés de la S-triazine et double résonance différée de l'azote dans la S-triazine à 4,2 k. : observation de la phase incommensurable de ThBr₄ à 4,2 K par RQN du brome." Paris 11, 1986. http://www.theses.fr/1986PA112021.
Повний текст джерелаAfter a review of the theory of NQR and of factors that relate to it, the various kinds of spectrometers used to study Nitrogen-14 and Bromine NQR at 4. 2 K are described. A delayed double resonance experiment in s-triazine, where the relaxation times are long, allowed the ѵ+ and ѵ- in this substance lines to be paired. It was also possible to observe emission signals at the ѵ- lines. Complete NQR spectra of Cyanuric chloride and melamine were obtained by the observation of two new lines and nine new lines, respectively, at 4. 2 K. A Bromine NQR study of ThBr₄ was carried out at 4. 2 K by the use of a half-wavelength transmission line connecting the r. F. Coil in the cryostat to the superregenerative spectrometer. Thus, we were able to observe at this temperature the incommensurate phase which was already known to exist at higher temperature
Halvachizadeh, Jaleh. "The Investigation of Reactions of Atomic Metal Anions with Small Hydrocarbons and Alcohols in the Gas Phase." Thèse, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/30646.
Повний текст джерелаButson, Jeffery M. "Electron Transfer and Other Reactions Using Atomic Metal Anions." Thèse, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/30561.
Повний текст джерелаChen, Shyh-Tzer, and 陳世澤. "Phase Transition of Clock Model with Dipolar and Quadrupolar Interactions." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/32482108431873078203.
Повний текст джерелаDas, Sambunath. "Quantum Phases and Magnetization Plateaus of Skewed Spin Ladders." Thesis, 2021. https://etd.iisc.ac.in/handle/2005/5702.
Повний текст джерелаYuan-po, Tai, and 戴元柏. "Gas-phase Host-Guest Chemistry in a Triple Stage Quadrupole Mass Spectrometry." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/29067586500586615028.
Повний текст джерела東海大學
化學系
87
The mass spectra of nitrogen-oxygen crown ethers and all nitrogen crown ethers have two major signals, [M+H]+and[2M+H]+. For these crown ethers, as the size of the macrocycle is larger, the steric barrier effect is greater, and it is difficult to form dimer complex. From collisionally activated dissociation (CAD) mass spectra of [M+H]+, we can find a series of losses of (C2H4O)n, (C2H5N)n, (C3H7N)n and some other fragments. The protonated dimer complex [2M+H]+ dissociates by loss of a monomer [M] without any other cleavage of the crown ether skeleton. The complex formation of nitrogen-oxygen crown ether with alkali metal has two tendencies. First, as the radius of metal ion greater, the form of complex ion fewer. Second, as the macrocycle of crown ether greater, the form of complex ion more. We conclude that it will induce the greater steric barrier by increasing the number of carbonic atom, and it is hard to form complex compound with the larger metallic ion clusters. In concert, it will have the same result by increasing the number of nitrogen atom of the crown ether. A special peak , [M+H]+, emerges from the CAD of [2M+H]+ forming with all nitrogen crown ether and alkali metal. It is to consider that all nitrogen crown ether has a greater proton affinity, so that it can catch a proton from the other crown ether on the dimer. Transition metal FeCl2, CoCl2, and NiCl2 can form [M+ACl]+ and [M-H+A]+ complexes with nitrogen-oxygen crown ether and all nitrogen crown ether, but CuCl2 can form these complexes with all nitrogen crown ether only. The reason may be the model of hard and soft acid and base. Additionally, the [M+ACl]+ complex dissociates by loss of HCl, giving [M+-H+A]+ fragment ion.
Li, Geng. "The effective temperatures of gas-phase biological molecules stored in a quadrupole ion trap." 2008. http://link.library.utoronto.ca/eir/EIRdetail.cfm?Resources__ID=771991&T=F.
Повний текст джерелаSantos, David Jorge Pires dos. "Identification of metabolites by liquid chromatography quadrupole time-of-flight mass spectrometric technique." Master's thesis, 2016. http://hdl.handle.net/10451/34605.
Повний текст джерелаAnalytical methods based on mass spectrometry and coupled to a chromatographic separation technique such as HPLC or GC, are crucial for investigating human metabolome, UPLC coupled with ESI-MS is a recent methodology representing an effective tool to separate and analyze molecules. The mains focus of this experimental work was to elucidate the influence of HILIC and Reversed-Phase chromatography on the analysis of compounds through ESI-MS. One additional aim was also to collect the identification data of selected compounds on a database for the building of a metabolomics library. This tool would allow to establish a match with results of subsequent analyses, minimizing the time spent on the identification of future analytes. Herein a UHPLC–MS method was applied for the first time to detect and identify a series of human metabolites and compounds found naturally on the human body. The procedures and molecules subjected to analysis are based on the protocol “Mass Spectrometry Metabolite Library of Standards”, commercially available by IROA Technologies. The kit contains a set of 619 standards. This work covers the first 253 compounds of the list. The analysis of compounds previously prepared as mixtures consisted on the chromatographic separation by HILIC or RP followed by positive or negative ESI-MS/MS. All the compounds were analyzed by the four possible combinations (HILIC, positive ESI; HILIC, negative ESI; RP, positive ESI; RP, negative ESI) as mixes of 12 standards distributed by four vials, one for each type of analysis. The results obtained were compiled and it was possible to conclude that HILIC is suitable to polar analytes whereas RP is preferable to non-polar compounds. Relatively to ESI, the positive ionization mode is applied with advantage to compounds that are able to accept a proton. Conversely, negative ESI is more effective to molecules which contain functional groups that readily lose a proton. Zwitterionic molecules are suitable to be analyzed by both modes. Some examples and exceptions to these general statements are presented.
Os métodos analíticos baseados em espectrometria de massa e acoplados a uma técnica de separação cromatográfica como HPLC ou GC, são cruciais para investigar o metaboloma humano. A análise por UPLC acoplada a ESI-MS é uma metodologia recente que representa uma ferramenta eficaz para separar e analisar moléculas. O foco principal deste trabalho experimental foi elucidar a influência de HILIC e cromatografia em fase reversa na análise de compostos através de ESI-MS. Um objectivo adicional foi também recolher os dados de identificação de compostos seleccionados numa base de dados para a construção de uma biblioteca de metabolitos. Esta ferramenta permitiria estabelecer uma correspondência com resultados de análises subsequentes, minimizando o tempo gasto na identificação de futuros analitos. Neste projecto, o método de análise por UHPLC-MS foi aplicado pela primeira vez para detectar e identificar uma série de metabolitos humanos e compostos encontrados naturalmente no corpo humano. Os procedimentos e moléculas submetidos à análise são baseados no protocolo "Mass spectrometry Metabolite Library of Standards", comercialmente disponível pela IROA Technologies. O kit contém um conjunto de 619 padrões. Este trabalho abrange os primeiros 253 compostos da lista. A análise de compostos previamente preparados em misturas consistiu na separação cromatográfica por HILIC ou RP seguida por ESI-MS/MS positiva ou negativa. Todos os compostos foram analisados pelas quatro combinações possíveis (HILIC, ESI positivo/ HILIC, ESI negativo/ RP, ESI positivo/ RP, ESI negativo) como misturas de 12 padrões distribuídos por quatro frascos, um para cada tipo de análise. Os resultados obtidos foram compilados e foi possível concluir que a separação por HILIC é adequada para analitos polares, enquanto que por RP é preferível para compostos não polares. Relativamente à ionização por ESI, o modo de ionização positiva melhor aplicado a compostos capazes de aceitar um protão. Por outro lado, a ESI negativa é mais eficaz para moléculas que contêm grupos funcionais que facilmente perdem um protão. As moléculas zwitteriónicas são passíveis de ser analisadas por ambos os modos. Alguns exemplos e excepções a estas ideias gerais são apresentadas.
Monteleone, Marcello, Antonio Tagarelli, Bartolo Gabriele, and Roberto Bartolino. "Development and optimization by experimental design of solid phase microextraction gas chromatography triple quadrupole mass spectrometry methods in aqueous matrices." Thesis, 2012. http://hdl.handle.net/10955/1145.
Повний текст джерелаIl presente lavoro di tesi relativo all‘attività di ricerca svolta durante il triennio di dottorato ha riguardato la messa a punto di metodi analitici per la determinazione di analiti in due distinte aree di interesse. La prima di ambito clinico ed ha riguardato la quantificazione in urina di metaboliti riconosciuti come marker in diagnostica clinica. In particolare ci si occupati della sarcosina come biomarker del tumore alla prostata, e di tre acidi: acido omovanillico (HVA), acido vanilmandelico (VMA) ed acido 5-idrossindoloacetico (5-HIAA) come marker urinari del neuroblastoma. Il secondo ambito di lavoro ha riguardato la quantificazione di inquinanti in matrici acquose, vale a dire carbammati ed acidi perfluoroalchilici. In particolare gli analiti, previa derivatizzazione con alchilcloroformiati (eccetto i carbammati), sono stati estratti dalle matrici acquose (acqua e urina) tramite la tecnica della microestrazione in fase solida (SPME) e successivamente analizzati mediante un gascromatografo con analizzatore di massa a triplo quadrupolo (GC-QqQ-MS). Le variabili significative della microestrazione in fase solida in ciascun metodo sono state ottimizzate tramite l‘approccio multivariato dell‘ ― Experimental Design‖. L‘utilizzo della tecnica SPME ha consentito di poter estrarre gli analiti direttamente dal campione da analizzare minimizzando i tempi di preparazione dello stesso e riducendo l‘uso di solventi organici, ottenendo metodi poco costosi e basso impatto ambientale. L‘utilizzo dello spettrometro di massa triplo quadrupolo, ha consentito di raggiungere livelli di sensibilità molto elevati e, nel contempo, di identificare gli analiti con maggiore sicurezza. In tutti i metodi sviluppati, sono stati ottenuti ottimi risultati in termini di linearità accuratezza e precisione. Anche i valori dei limiti di rilevabilità (LOD) e dei limiti di quantificazione (LOQ) ottenuti in ciascun metodo possono essere considerati soddisfacenti.
Università degli Studi della Calabria
Sagoo, Sandeep K. "Intrinsic Properties of Rhodamine B and Fluorescein Gas-phase Ions Studied using Laser-Induced Fluorescence and Photodissociation in a Quadrupole Ion Trap Mass Spectrometer." Thesis, 2011. http://hdl.handle.net/1807/29611.
Повний текст джерелаEliades, John Alexander. "A Radio Frequency Quadrupole Instrument for use with Accelerator Mass Spectrometry: Application to Low Kinetic Energy Reactive Isobar Suppression and Gas–phase Anion Reaction Studies." Thesis, 2012. http://hdl.handle.net/1807/32706.
Повний текст джерелаGardner, Myles Winston. "Development of chromogenic cross-linkers and selective gas-phase dissociation methods to assess protein macromolecular structures by mass spectrometry." Thesis, 2009. http://hdl.handle.net/2152/ETD-UT-2009-12-513.
Повний текст джерелаtext