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Test Specimens for SEM
Matějka, František ; Ryzí, Z.
In most applications SEM devices are utilized in the area of magnification quite far from the high limit. For such cases we prepare objects interesting for SEM by using special techniques of microfabrication. Those objects can be called test patterns. Compared with natural objects, they have an advantage: their geometry and dimensions are determined with high precision. Another advantage may be that the test pattern can be created from materials with well known properties. In our laboratories we prepare test specimens using electron-beam lithography and the anisotropic etching of silicon and using holographic techniques. We have designed the topography of anisotropically etched measuring test specimen ".mu.-scale".In most applications SEM devices are utilized in the area of magnification quite far from the high limit. For such cases we prepare objects interesting for SEM by using special techniques of microfabrication. Those objects can be called test patterns. Compared with natural objects, they have an advantage: their geometry and dimensions are determined with high precision. Another advantage may be that the test pattern can be created from materials with well known properties. In our laboratories we prepare test specimens using electron-beam lithography and the anisotropic etching of silicon and using holographic techniques. We have designed the topography of anisotropically etched measuring test specimen ".mu.-scale".
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Difraction in a scanning electron microscopie
Řiháček, Tomáš ; Mika, Filip ; Matějka, Milan ; Krátký, Stanislav ; Müllerová, Ilona
Manipulation with the primary beam phase in a transmission electron microscope (TEM) or a scanning transmission electron microscope (STEM) has drawn significant attention in the microscopy community in the recent years. Although a few applications were found long before, some are still subjects of a future research. One of them is the use of electron vortex beams, which has very promising potential. It ranges from probing magnetic materials and manipulating with nanoparticles to spin polarization of a beam in an electron microscope.\nThe methods for producing electron vortex beams have undergone a lot of development in recent years as well. The most versatile way is holographic reconstruction using computer-generated holograms modifying either phase or amplitude. As the method is\nbased on diffraction, beam coherence is a very important parameter here. It is usually performed in TEM at energies of about 100 – 300 keV which are well suited for diffraction on artificial structures for two reasons. The coherence of the primary beam is often reasonable, and the diffraction pattern is easily observed. This is however not the case for a standard scanning electron microscope (SEM) with typical energy up to 30 keV.
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Studium tenkých vrstev oxidu ceru metodami rastrovací tunelové mikroskopie (STM) a spektroskopie (STS)
Dvořák, Filip ; Mysliveček, Josef (vedoucí práce) ; Sobotík, Pavel (oponent)
Náplní práce je studium modelového systému CeO2/Cu(111) pomocí metody STM. Práce se zaměřuje na identifikaci růstového módu systému CeO2/Cu(111), studium závislosti morfologie povrchu systému na teplotě substrátu při přípravě vzorku a na určení atomární struktury připravených vrstev. Z hlediska vývoje teploty substrátu Cu(111) v průběhu depozice CeO2 byly vzorky připravovány třemi různými postupy - konstantní teplota, proměnná teplota a žíhání vzorku po depozici. Z měření morfologie vzorků byl určen rovnovážný růstový mód CeO2/Cu(111) jako 3D růst. Pomocí různé teploty substrátu při přípravě vzorku byly připraveny definované vzorky s různou morfologií. Čím nižší byla teplota v průběhu přípravy vzorku, tím více byl připravený systém neuspořádaný a rostla hustota defektů na jeho povrchu (dislokace, schody). Nejlepší epitaxe systému bylo dosaženo přípravou při proměnné teplotě substrátu. U vzorků připravených při teplotě vyšší než 400 řC byla na několika procentech povrchu pozorována vrstva CeO2(100). Vysoce rozlišené studium struktury CeO2/Cu(111) bylo provedeno na vzorcích s nízkým pokrytím připravených při konstantní teplotě. V prvních třech monovrstvách CeO2 byla na topografických měřeních patrná moir struktura, která vznikla kvůli nesouladu mřížkových konstant CeO2 a Cu(111). Atomárního rozlišení se...
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Pozorování zubní skloviny a dentinu v SEM
Wandrol, Petr ; Roubalíková, L. ; Autrata, Rudolf
Cílem práce bylo zjistit zda kyselý monomer na bázi éter akrylátu kyseliny fosforečné (AdHeSe) je schopen vytvořit stejně kvalitní vzor v zubní sklovině a dentinu jako konvenční ošetření 37 procentní kyselinou fosforovou (TotalEtch). Pro ošetřený skloviny se jako vhodnější jeví použití metody AdHeSe. U dentinu je možno použít obě metody, výsledky jsou prakticky shodné.
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Possible role of spermatogenic protein glyceraldehyde-3-phosphate dehydrogenase (GAPDHS) in mammalian sperm
Margaryan, Hasmik ; Dorosh, Andriy ; Čapková, Jana ; Postlerová, Pavla ; Philimonenko, Anatoly ; Hozák, Pavel ; Pěknicová, Jana
Sperm proteins are important for the structure and function of these specific, highly differentiated cells. Certain of these proteins play a role in sperm-egg recognition during primary or secondary binding at zona pellucida glycoprotein matrix. The aim of this study was to characterize the acrosomal sperm protein recognized by a monoclonal antibody (MoAb) Hs-8, prepared in our laboratory by immunization of BALB/c mice with human ejaculated sperm, and to test the possible role of this protein in gamete interaction. MoAb Hs-8 specifically labelled a 45 kDa protein from the sperm extract in the immunoblotting test. Sequence analysis identified this Hs-8 protein as GAPDHS. In order to perform a control tests, a commercial mouse anti-GAPDHS MoAb was applied. Both antibodies showed similar staining patterns using immunofluorescence labelling, transmission electron microscopy and immunoblot analysis. Moreover, both Hs-8 and commercial anti-GAPDHS antibodies blocked the secondary sperm-zona pellucida binding. Generally, GAPDHS was considered mainly as sperm-specific glycolytic enzyme involved in energy production during spermatogenesis and sperm motility and its role in the sperm head was unknown. In this study, we confirmed the potential additional role of GAPDHS as a binding protein that is involved in the sperm-zona pellucida interaction.
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The self-excited vibration of the NACA0015 profile
Vlček, Václav ; Zolotarev, Igor ; Kozánek, Jan
The two-dimensional flow patterns around the profile NACA0015 vibrating in self-excitation modes were measured in the wind tunnel by optical methods. The Mach numbers for the self-excited vibrations were in the interval 0.2 – 0.45. Results of the interferometric measurement and the profile kinematic movements during the self-oscillations are presented.
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Spermatological characters in Bothriocephalidea (Cestoda)
ŠÍPKOVÁ, Lenka
Spermiogenesis and ultrastructure of the spermatozoon of two bothriocephalidean cestodes, Oncodiscus sauridae and Senga sp., have been studied using transmission electron microscopy. The presence of a classical pattern for spermatological characters (spermiogenesis of type I with dense-material in early stages and sperm of type II with a characteristic ring of cortical microtubules in the anterior part) in Bothriocephalidea is discussed.
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Electrostatic assembly of alumina nanoparticles on nanocrystalline diamond films
Verveniotis, Elisseos ; Kromka, Alexander ; Rezek, Bohuslav
We apply atomic force microscope for local electrostatic charging of oxygen-terminated nanocrystalline diamond (NCD) thin films deposited on silicon, to induce electrostatically driven self-assembly of colloidal alumina nanoparticles into micro-patterns. The NCD films have sub-100 nm thickness and 60% relative sp2 phase content. We characterize charge contrast and stability in air, fluorocarbon oil and water by Kelvin force microscopy. We discuss factors influencing the charging process and demonstrate that the contrast of more than ± 1 V is needed to induce selfassembly of the nanoparticles via coulombic and polarization forces.
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