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Measurement of spruce needles by magnetic resonance imaging
Slivka, Ján ; Gescheidtová, Eva (referee) ; Bartušek, Karel (advisor)
The aim of this bachelor thesis is measuring of parameters of spruce needles from their 2D visual representation. To obtain the image, the magnetic resonance was used, specifically spin echo sequence. Further work is focused on digital image processing in order to obtain the necessary image information. The algorithm of linear mask operator was applied for reducing of noise and segmentation of image by thresholding was performed. Geometric properties of examined objects were obtained by integrated functions in MATLAB.
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Filtering methods in NMR measurements
Ryšavý, Ladislav ; Rajmic, Pavel (referee) ; Gescheidtová, Eva (advisor)
Bachelor's thesis deals with the wavelet transform and its use in processing and removing noise from images acquired by nuclear magnetic resonance. In the theoretical part of work is briefly described the principle of nuclear magnetic resonance, the wavelet transform is described, the selection of appropriate wavelets for filtering, two-dimensional wavelet transform for the processing of image data and appropriate tresholding techniques. The experimental part is focused on the filtration of magnetic fields and map images jaw joint as maps fields. They are filtering the results using different types of waves. It is shown through the evaluation of filtration ratio signal / noise and the steepness of the signal in the image.
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Propoasl of a laboratory workplace for verifying the NMR principle
Kropáč, Ondřej ; Bartušek, Karel (referee) ; Gescheidtová, Eva (advisor)
This project deals with the design of a laboratory workplace for verifying the basic principles of nuclear magnetic resonance. In the theoretical part of the project a basic knowledge of nuclear magnetic resonance are summarized, and the process of evaluation the results obtained from NMR signal is described. The proposed part of work is aimed at a design of a NMR spectrometer block diagram and a proposal of a resonant circuit and NMR probes. In the practical part the technologic process of the probes production and their settings are specified. The results of the designed probes comparison are in the last, measuring, part.
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Diffussion measurement by NMR
Vanko, Filip ; Gescheidtová, Eva (referee) ; Bartušek, Karel (advisor)
In Bachelor thesis is described the principle of MRI, the physical foundations of the phenomenon of magnetic resonance imaging, quantum and macroscopic model. Followed by a description of the mechanisms of relaxation of magnetic resonance phenomenon. In the following sections describes the basis of diffusion, each sequence for measuring diffusion NMR methods and the method of three measurements, which was used in experimental measurements. Last chapter deals with the practical. The results of measurements are evaluated in conclusion.
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Diffussion measurement by NMR
Vanko, Filip ; Gescheidtová, Eva (referee) ; Bartušek, Karel (advisor)
In Bachelor thesis is described the principle of MRI, the physical foundations of the phenomenon of magnetic resonance imaging, quantum and macroscopic model. Followed by a description of the mechanisms of relaxation of magnetic resonance phenomenon. In the following sections describes the basis of diffusion, each sequence for measuring diffusion NMR methods and the method of three measurements, which was used in experimental measurements. Last chapter deals with the practical. The results of measurements are evaluated in conclusion.
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Measurement of relaxation constants, using MR techniques
Pavlíček, Petr ; Chmelař, Milan (referee) ; Gescheidtová, Eva (advisor)
Bachelor‘s thesis deals with measuring methods of relaxation times T1 and T2 using nuclear magnetic resonance (NMR) and experimental measuring of conductive gels samples. In the theoretical part an analysis of the behavior of atoms placed in the magnetic field, basic principles of NMR functionality and commonly used measuring sequences for relaxation times detection are given. The experimental part is oriented to measuring both relaxation times of conductive gels samples, which were examined in terms of use in lithium-polymer (Li-Pol) accumulators. Relaxation times T1 were measured using Inversion Recovery (IR) method and relaxation time T2 using Hahn Echo and halfwidth methods.
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Designing an automated workplace for charge and high-impedance measurement
Nemček, Jakub ; Bartušek, Karel (referee) ; Gescheidtová, Eva (advisor)
This barchelor thesis is about Desig an automated workplace forchargeable and high-impedant measurements. This automated workplace is realized by tubular aspiration capacitor, which is connected via differential converter U/I to data acquisition switch unit HP 34970A. The data acquisition switch unit HP 34970A is also connected by serial line RS-232 to Computer (PC), on which the directed program Agilent VEE Pro 7.0 is installed. To the right connection data acquisition switch unit HP 34970A and PC is necessary to set the same parameters on data acquisition switch unit HP 34970A, such in I/O config and also in Instrument manager too. In Instrument manager is requisite to set Plug und Play driver for data acquisition switch unit HP 34970A. The programing in Agilent VEE Pro 7.0 is based on object oriented programming. To start the program press the button “START“ and automatic measuring of concentration air ionts, will start the process (the trend is marked to the graph). The program is indicated if the ventilator blows an air in the aspiration capacitor and draws the trend of voltage on this ventilator to the graph. To stop the program press the buton “STOP“. Measured data are exported to program Excel. For the export Excel has to be running before the process. The function is verifing by measuring of background negativ a positiv ionts, by influence of position the source of ionts behind the aspiration capacitor and by influence of materials (metal plate, paper carton, wood, conductive paint) to the concentration of negativ ionts.
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Measurement of relaxation constants by use of magnetic resonance
Kořínek, Radim ; Bartušek, Karel (referee) ; Gescheidtová, Eva (advisor)
This bachelor’s thesis is dedicated to principles of magnetic resonance and measurement of relaxation times. At theoretical part all basics methods of measurement (SE-spin echo, GE-gradient echo, SR-saturation recovery, IR- inversion recovery) of relaxation times T1, T2 resp. T2* are shown. At practical part T1 and flip angles are carefully observed. In case of measurement of relaxation time T2, the FID signal acquisition after 90° RF pulse is sufficient. T2* time is set from absorbtion line. For measurement of transversal relaxation method SE (often called as Hahn spin echo –90° RF pulse is followed by next 180° RF pulse) can be used. With GE method, the T2* relaxation is observed. Measurement of relaxation time T1 using RF impulses and inclinable angles A, is described at chapter 3. Every magnetization components during RF impulses are deeply described by mathematical formulas. Other chapter of this bachelor thesis describes some functions from MATLAB and their fitness for approximation of signal. From every tested functions, the lsqcurvefit function would be the best. Iteration method is most fitting function for approximation of FID signal.
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Measurement of selected samples relaxations by use of NMR
Kovalčík, Tomáš ; Gescheidtová, Eva (referee) ; Bartušek, Karel (advisor)
The work deals with nuclear magnetic resonance and principles of relaxation measurement and diffusion constants. Magnetic resonance is phenomenon, when energy in the form of RF pulse with Larmor frequency is added to this material in the magnetic field B0, the elements will be excited to a higher energy level. When you measure FID up to 90° RF pulse, from the absorption line, you will acquire . Further we can, for measurement of the transverse relaxation time T2, use the Spin echo method, that makes use of the 90° RF pulse and the series of 180° RF pulses. From measured values, the T2 relaxation time is directly acquired (inhomogeneity will prevent existence).
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