Teses / dissertações sobre o tema "Instrumentation RQN"
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Veja os 27 melhores trabalhos (teses / dissertações) para estudos sobre o assunto "Instrumentation RQN".
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Kachkachi, Noreddine. "Spectromètre RQN à base d’un SoC-FPGA : Conception numérique, vérification fonctionnelle et validation expérimentale". Electronic Thesis or Diss., Université de Lorraine, 2024. http://www.theses.fr/2024LORR0053.
Texto completo da fonteNuclear Quadrupolar Resonance (NQR) is a radio frequency spectroscopy technique that is very useful for non-invasive identification and analysis of chemical products. However, it suffers from low sensitivity which makes its instrumentation very challenging. In order to tackle these challenges and enhance the performances, especially sensitivity,we present in this thesis a solution which consists in a SoC-FPGA based compact spectrometer, where all the major digital hardware and software modules are integrated on a single System On Chip, including : a high pulse width resolution pulse programmer, a fully controllable transmitter, an acquisition module with real time digital signal processing, and storage of the acquired signal in an external memory, and a hardware debugger, in addition to embedded Linux applications that drive the spectrometer functionalities. This digital integration and miniaturisation brought noticeable performances of the spectrometers' overall functionality, especially in terms of sensitivity and portability. The designed spectrometer was successfully tested on several representative samples
Skolnik, Derek. "Building instrumentation". Diss., Restricted to subscribing institutions, 2008. http://proquest.umi.com/pqdweb?did=1790313721&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
Texto completo da fonteKASSAB, GHAZI. "Etude des milieux poreux par rmn : instrumentation specifique et etude des temps de relaxation". Paris 6, 1992. http://www.theses.fr/1992PA066524.
Texto completo da fonteHalidi, El Mohamed. "Études RMN et IRM en champ proche : développements et applications". Thesis, Montpellier 2, 2013. http://www.theses.fr/2013MON20261/document.
Texto completo da fonteThe principle of NMR is based on the detection of the magnetization originating from the spin of atomic nuclei such as 13C, 31P and 1H. The sample is placed in a static magnetic field, which polarizes the ensemble of spins and it is excited by radiofrequency pulses (wavelength about one meter), that tilt the axis of the magnetization. When the magnetization returns to equilibrium, it generates an electromagnetic field which is classically detected by a receiving antenna (coil with atuning/matching circuit) in inductive coupling.In this work, we propose the use of a micrometer-sized probe positioned in the vicinity of the object of interest, at a distance well shorter than the wavelength of the radiated NMR signal.Our microprobe presents innovative characteristics (i) a capacitive coupling (electric field component), (ii) reduced dimensions for an accurate positioning, which ensure the detection of NMR signal from the sample and (iii) it has a broadband, which allows use to detect any nuclei without being tuned to the Larmor frequency.To introduce you this new alternative, the tools necessary to the understanding of this work, in this case the principle of NMR/MRI and an introduction of the theory of the electric near field are given initially.We made also a state of the art of existing methods and techniques for measuring the NMR signal to identify the benefits that such a system (method : capacitive coupling and device : microprobe near field) can bring to the NMR technique.Then, we have characterized our microprobe to enhance its localized detection due to its small size (127 μm in diameter and 2mm in length). In this stage of characterization, we demonstrated that the NMR signal recovered by our antenna can be described by the electric near field expression :E(x, z) = A(Kz ) exp(i(z/L)) exp(−x/L) +Propagative TermFinally, we applied our system to make NMR studies such as spectroscopy, the relaxometry and NMR Imaging. We have outlined some potential projects to the continuity of this work
Pagnano, Marco Aurelio de Oliveira. "Automação de um espectrômetro por ressonância magnética nuclear pulsada". Universidade de São Paulo, 1993. http://www.teses.usp.br/teses/disponiveis/54/54132/tde-19082014-101639/.
Texto completo da fonteThis work describes the Project developped to automatize the pulsed nuclear magnetic resonance spectrometer housed in the laboratory of the professors José Pedro Donoso e Cláudio José Magon. To satisfy our needs we have improved their old equipment, at the level of hardware and software. Were built and programmed the parallel interface between the microcomputer and a pulse programmer made by Tecmag Inc. and with a fast digitizer (10 ns) Nicolet 430. The pulse programmer can control 75 independent output channels during 2048 time intervals. The software we developped allow us to control the whole pulse sequence on a very efficient and practical way. It was written in C-language, and provides the timing signals necessary to generate sofisticated pulse seqüencies, the data acquisition and data transfer to the host computer
Bolat, Murat. "Instrumentation tool for context-aware optimization". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 64 p, 2009. http://proquest.umi.com/pqdweb?did=1885467641&sid=5&Fmt=2&clientId=8331&RQT=309&VName=PQD.
Texto completo da fonteKienlin, Markus von. "Instrumentation et méthodologie en spectroscopie RMN in vivo suppression de l'eau, édition de spectre et localisation spatiale /". Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb37619193v.
Texto completo da fonteKienlin, Markus von. "Instrumentation et méthodologie en spectroscopie RMN du proton in vivo : suppression de l'eau, édition de spectre, localisation spatiale". Grenoble INPG, 1988. http://www.theses.fr/1988INPG0071.
Texto completo da fonteKarakaya, Yeliz. "Instrumentation for microscale measurement and characterization of bio-fibers". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 2.65 Mb., 112 p, 2006. http://proquest.umi.com/pqdlink?did=1037889801&Fmt=7&clientId=8331&RQT=309&VName=PQD.
Texto completo da fonteLaurent, Guillaume. "Increasing solid-state NMR sensitivity : instrumentation, fast acquisitions and signal processing". Electronic Thesis or Diss., Sorbonne université, 2020. http://www.theses.fr/2020SORUS183.
Texto completo da fonteSolid-state Nuclear Magnetic Resonance (NMR) is suffering from an intrinsic low sensitivity, despite recent improvements. Instrumentation, fast acquisition and signal processing approaches were investigated to circumvent this drawback as far as possible. Firstly, microcoils (Magic Angle Coil Spinning, MACS) were placed into rotors and inductively coupled to the standard probe coil. A time gain of ~ 5 was obtained for microquantities with a mass m ~ 100-200 µg. Secondly, acquisition time was decreased by mean of Carr-Purcell-Meiboom-Gill (CPMG) echoes for direct acquisition. Adequate processing is required to get the best enhancement from this technique. We provided a Python software to process data either using standard spikelets or superposition methods, or with a denoising method. A time gain of ~ 3-100 was possible. Thirdly, Non-Uniform Sampling (NUS) was chosen as a way to decrease acquisition time of indirect dimensions of multi-dimensional experiments. Poisson sampling revealed to be the best choice to limit artefacts, whereas hybrid sampling proved to be efficient on spectra with both broad and narrow peaks. A time gain of ~ 4 was achieved. Fourthly, spectra were processed with Singular Value Decomposition (SVD) denoising. We highlighted an overestimation of Gaussian peaks by ~ 20 %. Automatic thresholding was implemented, giving a time gain of ~ 2.3. Finally, computation time was decreased by ~ 100 by combining ‘divide and conquer’ algorithm, optimised libraries, hardware instruction calls and single precision. A comparison between Central Processing Units (CPU) and Graphical Processing Units (GPU) was provided
Rahima, Sidi-Boulenouar. "Dynamic monitoring of water status of plants in the fields under environmental stress : Design of a portable NMR and applied to sorghum". Thesis, Montpellier, 2018. http://www.theses.fr/2018MONTS081/document.
Texto completo da fonteToday, understanding how plants respond to water stress is essential to meet the challenge of developing new cultivars and new irrigation strategies, consistent with the maintenance of crop productivity with the evidence of global warming. In this context, the study of plant /water relations is of central interest for modeling plant and organ responses to biotic and abiotic constraints. Paradoxically, there are very few direct and non-invasive methods to quantify and measure the level and the flow of water in plants.For this purpose, we report on the development of an innovative methodology based on low-field Nuclear Magnetic Resonance Relaxometry (NMR). A dedicated NMR device to perform NMR measurements on living plants has been built in a climatic chamber that allows a control and careful modification of environmental parameters during experimentation over reliable periods of time at the laboratory. In parallel, complementary NMR imaging at high magnetic field to study, the anatomy, water content, phloem and xylem transport in sorghum plants were performed. The combination of these approaches allows us to determine innovant eco-physiological biomarkers and to design new experiments in the laboratory and even in the fields.One particular interesting result concertns the investigation of the spatial distribution of water stems (node and inter node) from low field NMR Relaxometry and 3D high resolution MRI images. The modification of the NMR relaxation parameters during dynamic diurnal cycle will be presented in normal and abiotic stress conditions. A direct application permits to extract eco-physiological biomarkers which allows to explore and model water fluxes during water stress and to analyze their impact on the development of sorghum plant. Our ultimate goal is to perform these NMR studies directly in the fields. Thus, a home made portable NMR device, working at 336kHz(8mT) is presented. The development and optimization of the homogeneity of a resistive magnet and Radio Frequency coils, NMR pulse sequences in order to respect the versatility and thermal conditions to maintain the plant intact are described in details. Finally we will present our investigations conducted with this device in the laboratory, in the greenhouses and in sorghum fields
Braz, Daniel Cesar. "Instrumentação para RMN em campo externo nulo com aplicação ao estudo de ligas FeV no estado de ordenação magnética". Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/76/76132/tde-22042010-160250/.
Texto completo da fonteThis work was motivated by the combination of the needs of the Nuclear Magnetic Resonance Laboratory with the technical features of the author of this dissertation. There was an urgent need in the group to document and improve the instrumentation and data processing software already developed to carry out the zero external magnetic field Nuclear Magnetic Resonance experiments. During the development of this work, it was verified the need for new developments, namely: development of software for data processing and development of automation of the apparatus used for the NMR experiments versus temperature. From the software developed for data processing, written in Matlab, it is easily possible processing the signal to reconstruct the spectrum. The data processing can be done in two ways: integrating the signal in the time domain or integrating its Fourier Transform. The processing time of the data was fast. The automation of the apparatus for controlling the temperature allows a more friendly interaction with the cryostat system. Finally, the NMR spectrometer was used to the study of FeV alloys in sigma phase. The experiments were performed to observe the 51V spectra (10 MHz to 100 MHz) and their quadrupolar oscillations, versus of the Fe concentration and temperature. With this study, it was possible to confirm that the spectra are relative to the 51V nuclei. The intensities of the five lines observed are coherent with the population of the V atoms in each of the Five crystallographic site (A, B, C, D e E), as determined by Neutron Diffraction. The quadrupolar couplings measured were found to be approximately 312 kHz for all sites studied.
Jennerjohn, Nancy Jane. "Instrumentation for the exposure assessment of airborne carbon nanotubes in the workplace". Diss., Restricted to subscribing institutions, 2009. http://proquest.umi.com/pqdweb?did=1998520781&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
Texto completo da fonteReader, Nicole. "Delaware's first long term instrumented bridge a prototypical instrumentation and installation plan /". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 156 p, 2007. http://proquest.umi.com/pqdweb?did=1338919141&sid=6&Fmt=2&clientId=8331&RQT=309&VName=PQD.
Texto completo da fonteUlu, Buket. "Monitoring And Checking Of Discrete Event Simulations". Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/1053305/index.pdf.
Texto completo da fonteAndreeta, Mariane Barsi. "Programação de um sistema de controle de RF e aquisição de dados para um espectrômetro de RMN de baixo custo". Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/76/76132/tde-22052012-173456/.
Texto completo da fonteThe objective of this project was the assembling and automatization of a low cost NMR spectrometer for the characterization of porous media. The study of porous media through NMR spectroscopy requires a low intensity magnetic field in order to avoid the problems related to the difference of magnetic susceptibility on the fluid-solid interface. For that reason, a low field electromagnet, operating on the proton frequency of 2MHz (0.047 Tesla) and of simple design was built. As to keep all the equipment as low cost as possible, the following components were also assembled in laboratory: the magnets power supply, a 2MHz amplifier, the quarter-wave components and the necessary softwares. The goal of the software developed was to control the RF generation and acquisition board, which was acquired from the enterprise Spincore, further named RadioProcessor. To achieve this goal, it was decided the development of a new API, in the C++ language, which uses the original boards API as a base in order to assemble a group of functions that are simpler and more intuitive to the end user. In addition, a script language was integrated to the APIs library, allowing users with little programming knowledge to write a program which controls the whole equipment in an easy way and also adding flexibility to the software, as it becomes easy to add new functions. This permits that the equipment be easily changed to include other applications in the future. Finally, a graphical interface was developed, which comprehends the equipment control software and the visualization of the data.
Sá, Alessandro Aguiar de Castro. "Desenvolvimento de instrumentação para o estudo de materiais magnéticos usando RMN com campo externo zero". Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/76/76132/tde-20112013-210032/.
Texto completo da fonteThe objective of this work was to repair and upgrade a double-resonance NMR spectrometer assembled in the 80s for studying solid-state materials. In 2001 this instrument was damaged by an atmospheric discharge that destroyed its digital modules, i.e., the pulse generator, digitizer, and averager. The work reported on here involved installing a new pulse-generator board and a programmable digital oscilloscope, both commercially available. These are computer-controlled by software developed by our research group. Although the spectrometer allows the use of double resonance NMR techniques for studying solid-state materials, the first experiments were done with magnetic materials, which required no superconducting magnet. Presently, the spectrometer is still being tested and improved. Even so, it is already capable of yielding important data in the study of magnetic materials
Chitikeshi, Sanjeevi. "Intelligent instrumentation and a robust dynamic model for an ultrasonic navigation system for improved neuro-surgery /". Available to subscribers only, 2007. http://proquest.umi.com/pqdweb?did=1456292241&sid=11&Fmt=2&clientId=1509&RQT=309&VName=PQD.
Texto completo da fonteMay, John Joseph. "Imaging the spectral earth an historical epistemology of scientific instrumentation and geographic perception in urban climatology /". Diss., Restricted to subscribing institutions, 2008. http://proquest.umi.com/pqdweb?did=1779835141&sid=11&Fmt=2&clientId=1564&RQT=309&VName=PQD.
Texto completo da fonteMares, David M. "Developmental laboratories for biomedical instrumentation and digital signal processing with virtual instrument technology and diverse software techniques". Laramie, Wyo. : University of Wyoming, 2006. http://proquest.umi.com/pqdweb?did=1292461511&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.
Texto completo da fonteWright, Shelley Adams. "A spatially resolved kinematic study of high redshift star forming galaxies development and use of adaptive optics instrumentation /". Diss., Restricted to subscribing institutions, 2008. http://proquest.umi.com/pqdweb?did=1692099821&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
Texto completo da fonteDang, Phuc Hung. "Développement d’aimant bas champ pour RMN Portable : Conception et construction". Thesis, Lyon, INSA, 2015. http://www.theses.fr/2015ISAL0007/document.
Texto completo da fonteThis thesis focuses on the development of a magnet system for NMR applications with high homogeneity while maintaining the static magnetic field B0 as high as possible (100 ppm, 0.12T). Due to the application goals, the magnet dimensions are predefined as well as those of the region of interest according to the size of the used permanent magnets. Such system is dedicated to biomedical and agroalimentary applications. The goal of this research has been firstly, the discussion of parameters of magnetic materials which are essential to the construction of portable NMR magnets, and then the choice of the permanent magnet material the “NdFeB” that was explained. A compromise between the portability, price and the sensitivity has led to the design of a prototype of portable NMR magnet with a simple system of arrangement of 24 permanent magnets. The magnetic field and the homogeneity of the system were calculated and simulated by using ANSYS software and these results were correlated to those obtained by the Radia software. A new shim method has been used to increase the homogeneity and correct the field B0 imperfection. Based on these results, a prototype was realized. The results of the magnetic field strength and homogeneity obtained by measurements are in good correlation with the results obtained by simulation. Sufficient accuracy was reached to take into account and correct errors due to manufacturing tolerances of the magnets. Another magnet system based on Mandhalas configuration (Magnet Arrangement for Novel Discrete Halbach Layout) was studied. The comparison between two configurations made from circle and square magnets was performed by 2D simulation (using three criteria: mass, homogeneity and the magnetic field strength). The Mandhalas made from circle magnets give better results (0.32 T, 178 ppm). The 3D simulation was carried out to evaluate the total system. From these results, a passive shim system was also used in this case and the homogeneity significantly increases
Biscegli, Clovis Isberto. "Espectrômetro para a transferência de polarização elétron-núcleo (efeito Overhauser)". Universidade de São Paulo, 1994. http://www.teses.usp.br/teses/disponiveis/76/76132/tde-01042014-143911/.
Texto completo da fonteThis work describes in details the arrangements that must be accomplished for development of a spectrometer for Dynamic Nuclear Polarization - DNP (Overhauser Effect). Also, the construction project of a 14 MHz pulsed NMR spectrometer and drawings of a homemade EPR cavity for X-band (~ 9,2 GHz) are shown. The DNP probe built for the experiments and modifications done on the EPR spectrometer existing at Laboratory of Magnetic Resonance are discussed in detail. Results on the enhancement of the NMR signal due electron-proton dynamic interactions are presented. NMR imaging of very small objects, 1 mm diameter glass tube filled with 5 ~10 ul of 2,2 mM of free radicals (TEMPOL) solution, obtained through back projection reconstruction NMR tomography method, are presented
Josse, Gwendal. "De l'adhérence à l'anti-adhérence à travers le Probe Tack". Paris 6, 2001. http://www.theses.fr/2001PA066442.
Texto completo da fonteAraujo, Roberto Paulo Andrioli de. "Scalable data-flow testing". Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/100/100131/tde-14112014-155259/.
Texto completo da fonteTeste de fluxo de dados (TFD) foi introduzido há mais de trinta anos com o objetivo de criar uma avaliação mais abrangente da estrutura dos programas. TFD exige testes que percorrem caminhos nos quais a atribuição de valor a uma variável (definição) e a subsequente referência a esse valor (uso) são verificados. Essa relação é denominada associação definição-uso. Enquanto as ferramentas de teste de fluxo de controle são capazes de lidar com sistemas compostos de programas grandes e que executam durante bastante tempo, as ferramentas de TFD não têm obtido o mesmo sucesso. Esta situação é, em parte, devida aos custos associados ao rastreamento de associações definição-uso em tempo de execução. Recentemente, foi proposto um algoritmo --- chamado \\textit (BA) --- que usa vetores de bits e operações bit a bit para monitorar associações definição-uso em tempo de execução. Esta pesquisa apresenta a implementação de BA para programas compilados em Java. Abordagens anteriores são capazes de lidar com programas pequenos e de médio porte com altas penalidades em termos de execução e memória. Os resultados experimentais mostram que, usando BA, é possível utilizar TFD para verificar sistemas com mais de 250 mil linhas de código e 300 mil associações definição-uso. Além disso, para vários programas, a penalidade de execução imposta por BA é comparável àquela imposta por uma popular ferramenta de teste de fluxo de controle.
Goutailler, Florent. "Polarisation dynamique nucléaire a basse température et fort champ magnétique pour des applications biomédicales en imagerie spectroscopique par résonance magnétique". Phd thesis, Université Claude Bernard - Lyon I, 2011. http://tel.archives-ouvertes.fr/tel-00684287.
Texto completo da fonteBaswell, Michael Alan. "Advanced instrumentation in metal casting applications : a dissertation presented to the faculty of the Graduate School, Tennessee Technological University /". 2008. http://proquest.umi.com/pqdweb?sid=2&vinst=PROD&fmt=6&startpage=-1&clientid=28564&vname=PQD&RQT=309&did=1674416921&scaling=FULL&vtype=PQD&rqt=309&TS=1248288594&clientId=28564.
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