National Repository of Grey Literature 22 records found  previous3 - 12next  jump to record: Search took 0.00 seconds. 
Design of Planar Optical Waveguide
Dvořák, Václav ; Friedl, Martin (referee) ; Nešpor, Dušan (advisor)
This bachelor´s thesis deals with the theoretical fundamentals of planar optical waveguides, possibilities of their fabrication and design of planar optical waveguide. Design of waveguide will be simulated using FDTD Solutions and Ansoft HFSS. These two software use different techniques for computational simulation. The parameters of waveguide will be modified to achieve better performance of waveguide. The result will be compare the properties of waveguides. There will be also described design of implementing waveguide.
Detection of closure of chamber doors for an electron scanning microscope
Obšitník, Michal ; Drexler, Petr (referee) ; Nešpor, Dušan (advisor)
The aim of this work is to design a suitable sensor for the detection of the chamber door position in an electron scanning microscope when the pressure in the vacuum chamber is changed and a control program is assembled to the selected sensor. The detected motion is within one millimeter. In the first part, the work is aimed at getting acquainted with the principle of functioning of the electron scanning microscope and with the basic types of sensors for position and mechanical force detection. Subsequently, the sensors are compared according to three basic categories: price, range, and resistance to external influences. Selected theory-based sensors are tested to exclude inappropriate sensors from use. After testing, the Interlink FSR-402 resistance sensor is selected. The scheme is connected to the sensor and the operation control program is created. The result of this work is a force sensing sensor, which is triggered by the pressure of chamber door on the chamber wall when creating a vacuum and a control program that controls the results measured from the sensor and adjusts them as required.
Design and Realization of Metamaterial
Kovaľová, Soňa ; Drexler, Petr (referee) ; Nešpor, Dušan (advisor)
The thesis discusses the design of periodic resonant structures, studying of their impact to surrounding electromagnetic field and realisation of magnetoinductive lens with potential application in nuclear magnetic resonance imaging. Frequency tuning of structure by variation of different parameters is described. The finite element method in Ansys HFSS was used to analyse the properties of designed structures.
Electroamgnetic wave propagation study in heterogeneous structures
Nešpor, Dušan ; Raida, Zbyněk (referee) ; Fiala, Pavel (advisor)
The sight of work is study form high frequency electromagnetic wave in inhomogeneous materials. The main are refractions and reflection on boundary of materials with different properties and form electromagnetic wave in periodic structure. The work contain analytic and numeric solution. The numeric solution was realized in program COMSOL.
Realization of the positioning device for mapping electromagnetic fields
Jozífek, Eduard ; Drexler, Petr (referee) ; Nešpor, Dušan (advisor)
This paper deals with the measurement of electromagnetic fields in reactive zone and proposing an automated workstation for its measurement. The sample is a periodic structure of the circular split resonators, which is due to the magnetic field generated from the supplied loop antenna is brought to resonance and itself becomes imaginary antenna. The measuring probe is placed on the cross-positioning table movement is controlled by two stepper motors.
Modern methods for Chip Attach
Nešpor, Dušan ; Novotný, Marek (referee) ; Szendiuch, Ivan (advisor)
The work deals with packaging and die attach issues. The general aim of this investigation is thermomechanical stress between package and substrate depending on different thermal and mechanical properties of used materials. Work contains modeling with program ANSYS and practical tests with testing packages. Determining a place in the solder with the maximal and the minimal stress values and determining of the stress distribution for all materials are the results of this research.
A Brief Design of Optical Resonators
Hubík, Daniel ; Nešpor, Dušan (referee) ; Kadlec, Radim (advisor)
This bachelor thesis is focused on analysis of split-ring resonators in THz region. Simulations were made by finite elements method and by finite-difference time-domain method. At first we created a resonating structure that works in GHz region. Then we were observing a dependence of movement of resonant frequency on the size of resonator. In the final chapter we assigned frequency dependent values of permitivity to such structure. As the result we simulated working resonator at frequency 500THz. All simulations have been made in program HFSS ANSYS and Lumerical FDTD Solutions.
Design and Realization of Phantom for MRI
Šablatura, Martin ; Čáp, Martin (referee) ; Nešpor, Dušan (advisor)
Paper studies the principles of MRI and composition of MR system. Main part of thesis focuses on design, mixing and measurement of solution for MR system phantom. Teoretical part of paper focuses on problematic of MRI and phantoms for MR system, including description of specific phantom, which is then realised. Paper contains methods for designing proposed kind of phantom and its followed measurement. Part of paper also focuses on mathematical models of elaboration of data aquired from measurements.
Design and Realization of the Bird Cage Coil for MRI
Sedlář, Petr ; Drexler, Petr (referee) ; Nešpor, Dušan (advisor)
The work deals with the design and experimental production of the model type Birdcage coil used for magnetic resonance imaging system (MRI). The work deals with the design and behaviour of the model type Birdcage coil volume designed for imaging system for magnetic resonance imaging (MRI). Volume coils are generally very useful for use in MRI, because in transversal design allow easy access into the cavity when the flow vector of magnetization. The aim of the work was to construct a numerical model of transversal coil type Birdcage of the predefined dimensions. The created the coil tuned the desired resonant frequency having regard to maximize performance in the measured sample migrated. The modeling coil experimentally produced and measurements also confirm the accuracy of the numerical model.
Detection of closure of chamber doors for an electron scanning microscope
Obšitník, Michal ; Drexler, Petr (referee) ; Nešpor, Dušan (advisor)
The aim of this work is to design a suitable sensor for the detection of the chamber door position in an electron scanning microscope when the pressure in the vacuum chamber is changed and a control program is assembled to the selected sensor. The detected motion is within one millimeter. In the first part, the work is aimed at getting acquainted with the principle of functioning of the electron scanning microscope and with the basic types of sensors for position and mechanical force detection. Subsequently, the sensors are compared according to three basic categories: price, range, and resistance to external influences. Selected theory-based sensors are tested to exclude inappropriate sensors from use. After testing, the Interlink FSR-402 resistance sensor is selected. The scheme is connected to the sensor and the operation control program is created. The result of this work is a force sensing sensor, which is triggered by the pressure of chamber door on the chamber wall when creating a vacuum and a control program that controls the results measured from the sensor and adjusts them as required.

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