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Evaluation of Gas Flow at the Proposed Shapes of Scintillation Detector Aperture Sieves
Matloch, Roman ; Špinka, Jiří (referee) ; Maxa, Jiří (advisor)
This work describes briefly electron microscopy issue and physical model of fluid flow. Then the simplified three-dimensional model of scintillation detector will be created in SolidWorks system for 3D cubical models. The gas flow behind the screening in this 3D model will be analyzed and compared by method of finite cube method in SolidWorks Flow Simulation system. This screening will be analyzed in several variants: the screening with 0.6 mm opening and the screening with net-like openings. The results of analyses will be compared according to the requirements. The appropriate shapes from the analyzed parts will be practically measured.
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The effect of the shape of the intake ports for pumping in a Scintillation detector.
Flídr, Karel ; Vyroubal, Petr (referee) ; Maxa, Jiří (advisor)
The thesis is concerned with the design of the shape of suction canals used for pumping in the scintillation detector. The goal is to perform analysis of the model of the detector according to the current conception and then perform an optimalisation of the suction canals as per demands to their function. In the beginning of the thesis the history of the microscope and electron microscopy is described. The next chapter is focused on a more detailed description of ESEM. The following charter is dedicated to describing the scintillation detector.The thesis recounts the kinds of liquid flow. In conclusion the programs SolidWorks and Ansys Fleunt are described. Next part of this thesis describes in detail parameters‘ settings of simulation calculation. Following chapter introduces designed changes of suction channels shape and its results are shown and described.
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Construction scintillation detector with one aperture for environmental scanning electron microscope
Přichystal, Vít ; Vyroubal, Petr (referee) ; Maxa, Jiří (advisor)
The thesis is focused on the design of a scintillation detector with one screen for environmental scanning electron microscope. At the beginning of the work is an introduction to microscopy. Further work is focused on the description of ESEM microscope and a scintillation detector. The following chapter is devoted to the dynamics of flow. They list the types of flow and mathematical description of equations. The next chapter is about using the software and the way of solution of flow. In the following chapter describes a proposal of the diaphragm and extraction method of the detector area. They are described some of type aperture. The last chapter is the conclusion, where the work is summarized.
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Comparison of flow conditions in the gas detector used in the aperture and screen
Hubáček, Jiří ; Špinka, Jiří (referee) ; Maxa, Jiří (advisor)
The first part of the thesis deals with electron microscopy and physical model fluid flow. In the next part, a three-dimensional model is created in programme SolidWorks. It is the model of scintilating detector with aperture or screen with three hundred little apertures. These models are submitted to analysis focusing on investigation of the gas flow at different pressure in chamber of specimen ESEM using Cosmos FloWorks system. The results of the analysis of both apertures variants are compared with the request to minimize the pressure in the trajectory of the secondary electrons as well as in the chamber of specimen.
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Observation of Insulators in ESEM
Matějka, Milan ; Špinka, Jiří (referee) ; Jirák, Josef (advisor)
This graduation theses in introduction deals with principle and problems of electron signal detection in scanning electron microscopy and charging of insulating specimens in SEM. The experimental part of the thesis describe the methods of qualification and quantification of insulating specimen charging effect observed in environmental scanning electron microscope through the use of ionisation and scintillation detector in dependence on water vapour pressure in specimen chamber. The goal of the thesis is formation of the methodics useful to evaluate charging effect at insulating specimens observing and on the basis of measuring, determine optimal conditions for insulating specimen observation with ionisation and scintillation detector.
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Analysis of the gas glow
Hladká, K. ; Maxa, J. ; Neděla, Vilém ; Vyroubal, P. ; Vaculík, S. ; Hlavatá, P.
In order to optimize the shape of the Differentially pumped chamber in the area of the Primary Electron Beam passage for the current concept of the location of the foci of the Primary Electron Beam, it was necessary to adapt to the size and shape of the limitations of the existing structure. On fig. 1a is the total cross sectional view of the Differentially pumped chamber. Three variants were examined: Current concept with an easily machined shape of the passage of the primary beam, semi-closed concept with a conical shape, cone concept with a wider cone.
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Use systems for the analysis of gas flow
Maxa, J. ; Neděla, Vilém ; Hladká, K. ; Vyroubal, P. ; Vaculík, S. ; Hlavatá, P.
Environmental scanning electron microscope is explaining withdrawing of two differentially pumped chambers in a drawing area. To solve this problem is used finite volume method. This method includes several steps: - With using of mesh the area is dividing into discrete volume. - Discretization and balancing of the unknown quantities in each finite volume - Numerical solution of discretized equations.
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Physical and biocatalytic properties of polyvinyl alcohol lens-shaped particles versus spherical polyelectrolyte complex microcapsules
Schenkmayerová, A. ; Bučko, M. ; Gemeiner, P. ; Treľová, D. ; Lacík, I. ; Chorvát Jr., D. ; Ačai, P. ; Polakovič, M. ; Lipták, L. ; Rebroš, M. ; Rosenberg, M. ; Štefuca, V. ; Neděla, Vilém ; Tihlaříková, Eva
Direct comparison of key physical and chemical-engineering properties of two representative matrices for multipurpose immobilisations was performed for the first time. Polyvinyl alcohol lens-shaped particles LentiKats and polyelectrolyte complex microcapsules were characterised by advanced techniques with respect to the size distribution of the particles, their inner morphology as revealed by fluorescent probe staining, mechanical resistance, size-exclusion properties, determination of effective diffusion coefficient and environmental scanning electron microscope imaging. Recombinant cells E. coli overexpressing enzyme cyclopentanone monooxygenase were immobilised in polyelectrolyte complex microcapsules and LentiKats for comparison of their operational stability using model Baeyer-Villiger oxidation of (±)-cis-bicyclo[3.2.0]hept-2-en-6-one to regioisomeric lactones as important chiral synthons for potential pharmaceuticals.
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Progress in imaging techniques for characterization of polyelectrolyte complex microcapsules as encapsulation matrice for biocatalysts
Bučko, M. ; Gemeiner, P. ; Vikartovská, A. ; Schenkmayerová, A. ; Bertóková, A. ; Lacík, I. ; Chorvát Jr., D. ; Neděla, Vilém
Polyelectrolyte complex microcapsules showed to be an univerzal encapsulation matrice for wide range of biocatalysts including viable, native and recombinant bacterial cells, non-viable bacterial cells as well as enzymes. Developed continuous encapsulation protocol based on the polyelectrolyte complexation of oppositely charged polymers enabled production of uniform microcapsules with a controlled shape, size, membrane thickness, permeability and mechanical resistance. The characterisation and control of the microcapsule properties including the inner structure and surface properties was inevitable to determine their proper function and predictability in important applications such as the stabilisation and reuse of encapsulated biocatalysts for more efficient production of valuable compounds. Recent utilisation of unique environmental scanning electron microscope enabled an innovative observation and characterization of capsule morphology in native and fully hydrated state. Achieved results and comparison with previously used conventional microscopic techniques will be presented.
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