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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Analýza tvaru sacích kanálů současné koncepce diferenciálně čerpané komory / Analysis of the shape of the intake ports of the current concept differentially pumped chamber

Bílek, Michal January 2015 (has links)
This master´s thesis discusses the analysis of the shape of the intake ports of differentially pumped chamber for the current concept. The first part is an introduction to the microscopy issue, then it is focused on ESEM microscopes and it also includes a describtion of the Flow dynamics and a mathematical describtion. In the following chapters the software Solid Works, where the model of differentially pumped chamber is created, and the software Ansys Fluent, which is used for analysis, are described. The second part concerns the proposed concepts and the results of their simulations. At the end of the work the results are analyzed and evaluated.
92

Studium vlastností povrchových plazmonových polaritonů na magnetických materiálech / Study of Properties of Surface Plasmon Polaritons on Magnetic Materials

Dvořák, Petr January 2011 (has links)
The diploma thesis deals with the experimental study of surface plasmon polaritons (SPPs) on nano-structures with the Au/Co/Au multilayer. Plasmonic structures were prepared by the electron beam lithography and by the focused ion beam. A Scanning optical near-field microscope was used for detection of surface plasmon polaritons. SPPs were confirmed by the experiment with different polarizations of the illuminating light. Furthermore, differences in plasmon interference wavelengths was measured for different surface dielectric functions. Finally, the decantation of the SPPs interference image was measured in dependence on the external magnetic field.
93

Optická pinzeta pro koherencí řízený holografický mikroskop / Optical tweezers for coherence-controlled holographic microscope

Straka, Branislav January 2013 (has links)
In the master's thesis, there has been described and explained the principle of operation of the second generation coherence controlled holographic microscope (CCHM2) designed at the Brno University of Technology. There has also been listed theoretical description of the operation of the optical trap, together with the calculation of the forces acting on it, ways of measuring the stiffness of the optical trap and the principle of~creating a time-shared optical traps. The optical tweezers forming a separate module connectable to CCHM2 was designed. Simulation and optimization of parameters of the optical system, mechanical design, manufacturing documentation, current source to power the laser diode which allows to control the diode output power by the controller card connected to the PC was designed. The galvano-optics mirror angle is controlled by the PC card too. The optical tweezer has been designed, manufactured and tested in conjunction with the CCHM2.
94

Analýza vlivu proudění plynu v oblasti umístění vzorku v komoře enviromentálního rastrovacího elektronového mikroskopu / Analysis of the influence of the gas flow in the placement of the sample in the chamber of the environmental scanning electron microscope

Bednář, Eduard January 2016 (has links)
This thesis deals with the simulation of fluid dynamics in environmental scanning electron microscope and evaluate solvers setup, the degree of discretization, choice of turbulent model and proposal optimal design of environmental scanning electron microscope. The theoretical part describes the issue of environmental scanning electron microscopy, software SolidWorks and ANSYS Fluent, basic equations describing fluid status, fluid turbulence, the mean free path of molecules and electron scattering. The practical part of the thesis is to create the model of environmental scanning electron microscope AQUASEM II in CAD system SolidWorks and simulation of fluid flow in the sample chamber before aperture PLA1 by ANSYS Fluent. A series of simulations provided the perfect setting solver. These knowledge are used in the second stage of the practical part, where is proposed optimal shape of the table sample and the input aperture PLA1.
95

Automatizované procedury pro Koherencí řízený holografický mikroskop / Automated Procedures for Coherence Controlled Holographic Microscope

Dostál, Zbyněk January 2016 (has links)
Coherence-Controlled Holographic Microscope (CCHM) and a Fluorescence Holographic Microscope (FHM) were developed particularly for quantitative phase imaging and measurement of live cell dynamics, which used to be a subject of digital holographic microscopy (DHM). CCHM and FHM in low-coherence mode extend capabilities of DHM in the study of living cells. However, this advantage following from the use of low coherence is accompanied by increased sensitivity of the system to its correct alignment. Therefore, the introduction of an automatic self-correcting system is inevitable. Accordingly, in the thesis, the theory of a suitable control system is derived and the design of an automated alignment system for both microscopes is proposed and experimentally proved. The holographic signal was identified as a significant variable for guiding the alignment procedures. On this basis the original basic realignment algorithms were proposed, which encompasses the processes for initial and advanced alignment as well as for long-term maintenance of the microscope aligned state. Automated procedures were implemented in both microscopes unique set of robotic mechanisms designed and built within the frame of the thesis work. All of the procedures described in the thesis were in real experimentally proved at real microscopes in the experimental biophotonics laboratory. In addition, the control software, which contains the needed automated procedures, was developed for FHM.
96

Koherencí řízený holografický mikroskop nové generace / New Generation of a Coherence-Controlled Holographic Microscope

Slabý, Tomáš January 2015 (has links)
This doctoral thesis deals with design of a new generation of coherence-controlled holographic microscope (CCHM). The microscope is based on off-axis holographic configuration using diffraction grating and allows the use of temporally and spatially incoherent illumination. In the theoretical section a new optical configuration of the microscope is proposed and conditions for different parameters of the microscope and its optical components are derived. The influence of different sources of noise on phase detection sensitivity is studied. In the next section design of experimental setup is described and automatable adjustment procedure is proposed. Last section describes experimental verification of the most important optical parameters of the experimental setup. When compared to previous generation of CCHM, the newly proposed configuration uses infinity-corrected objectives and common microscope condensers, allows more space for the specimens, eliminates the limitation of spectral transmittance and significantly simplifies the adjustment procedure so that automation of this procedure is possible.
97

Metody SPM založené na sondách vyrobených z křemenného rezonátoru / SPM Methods Based On The Quartz Resonator Probes

Wertheimer, Pavel January 2015 (has links)
The thesis is focused on development of scanning probe microscope systems, especially development and implementation of quartz resonator probes. The quartz resonator probes, compared to the standard silicon cantilevers, have several advantages. It is in particular their mechanical properties and possibility of direct electrical readout of the deflection signal. Due to the fact, the probes are easy to implement even into more complex SPM systems. The thesis deals with development of universal and open SPM control system electronics. The electronics consist of the commercial SPM control and oscillation units, the development of the other electronic parts (such as the high voltage amplifier and the preamplifier units) is described in the thesis. Further, the thesis reports on development of the qPlus UHV LT SPM microscope system that was carried out at Universität Hamburg. Part of it was development of the qPlus preamplifier able to operate at liquid helium temperature. The third topic of the thesis is the implementation of qPlus technology into the UHV VT SPM microscope suitable to operate in situ with a scanning electron microscope. The qPlus sensors and the universal UHV preamplifier were designed and manufactured. Test measurements were conducted on all of the developed systems.
98

Metodika stanovení velikosti detekovaného signálu v environmentálním SEM / Method for evaluation of signal level value in environmental SEM

Kršňák, Jiří Unknown Date (has links)
This work deals with the evaluating of the signal level value from the sample in the environmental SEM. In work there were processed the comparison of the osciloscopic method for the evaluating of the signal level value in the environmental SEM, the method for the evaluating of the signal level from the grey level of the sample images and the method for the evaluating of the signal level from the osciloscop. There are described the advantages and disadvantages of the methods and procedures for processing the methods.
99

Studium efektu aplikace celulózových vláken v cementových kompozitech / Study of the effect of the application of cellulose fibers in cementitious composites

Dvořák, Richard January 2016 (has links)
This diploma thesis is focused on composition and processing of cellulose fibers and their usage in cementitious composites. It describes key attributes of cellulose fibers, which has to be acquired for effective use in cement composites. There are stated effects of cellulose fibers on concrete properties, such as workability, physical and mechanic attributes and freeze-thaw resistance. In experimental part is designed a mixture with portion of cellulose fibers. There has been performed various tests to define the effect of cellulose fibers. There was designed experiment to determine its alkali resistance for fibers itself, and possible changes in microstructure of fibers were analyzed by optic and electron scanning microscope.
100

Srovnání vlivu tvaru konvergentní a Lavalovy dýzy v clonkách detektoru na výsledný tlak na dráze sekundárních elektronů pomocí systému CAE / Using Computer Aided Engineering for analyse the detector

Vyroubal, Petr January 2011 (has links)
This master's thesis deals with influence of the shape comparison of convergent and Laval nozzles in the secondary electron detector shutters to the resulting pressure and gas flow in the secondary electron detector for environmental scaning electron mictoscope. To the detector analysis are used Computer Aided Engineering systems CAD and CAE, SolidWorks and SolidWorks Flow Simulation.

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