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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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Scanning tunneling microscopy (STM) and spectroscopy (STS) study of thin ceria films
Dvořák, Filip ; Mysliveček, Josef (advisor) ; Sobotík, Pavel (referee)
The contents of this study is the investigation of model catalyst CeO2/Cu(111) by STM. The aim of the work is identifying the growth mode of CeO2/Cu(111), studying the surface morphology dependence on substrate temperature during the sample preparation and determination of the atomic structure of the prepared layers. In terms of evolution of substrate temperature during the deposition samples has been prepared by three different methods - a constant temperature, variable temperature, and annealing the sample after deposition. The growth mode of the layers CeO2 has been determined as 3D growth. Samples with different morphology have been prepared by varying temperature of substrate during the preparation. With decreasing sample preparation temperature the roughness and defect density on surface have been increasing. The best epitaxy has been achieved by temperature gradient preparation. Samples which have been prepared with temperature above 400řC have been partially covered by layer CeO2(100). Measurements with hight resolution have been performed on the samples with low coverage. The first three monolayers of CeO2 have shown a moir pattern which has been caused by mismatch in lattice parameters. Atomic resolution has been achieved only in the first and the second monolayer CeO2. The absence of defects in...
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Pozorování zubní skloviny a dentinu v SEM
Wandrol, Petr ; Roubalíková, L. ; Autrata, Rudolf
The purpose of this study was to investigate whether the acidic monomer based on the phosphoric acid ether acrylate can create the same retentive pattern in enamel and dentin as the conventional treatment with the 37% phosphoric acid. The surface of enamel in the AdHeSe group was slightly undulated, the retentive pattern was regular and moderate. In the TotalEtch group more irregularities and a clearer retentive pattern were observed. The dentin surface was similar in both groups- it was clean without the smear layer, the dentin tubuli were open, the collagen network was seen on the dentin surface as well as in the dentin tubuli.
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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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