Papers by Keyword: Confocal Microscopy

Abstract: This paper focuses on the use of nonlinear acoustic spectroscopy with one excitation signal for NDT of concrete parts exposed to high temperature. The rate of the temperature rise, the highest achieved temperature, time of exposure to elevated temperature and the cooling rate has an influence on the overall damage of concrete structures affected by fire. The test specimens described in this paper have been heated for various periods of time and at a different temperature. Nonlinear acoustic spectroscopy method was performed before and after heat load.

Abstract: We proposed an experimental technique for determining the sputtering yields of two-component semiconductors – gallium arsenide and indium arsenide by low-energy argon ions. It was suggested to measure the volume of a crater formed by inert ions bombarding on the target surface using the method of scanning laser confocal microscopy. It was demonstrated that in the energy range from 100 to 300 eV, the energy dependence of sputtering yields for these materials is practically linear. It is established that the sputtering yields for normal bombardment by argon ions at optimum energy of 150 eV are equal to Y(GaAs) = 0.41 and Y(InAs) = 0.73. It is found that an increase in the etching time of the surface of gallium arsenide and indium arsenide leads to a characteristic transformation of the surface relief. The studies of the sputtering of two-component targets indicate the initial strong non-stechiometry. Etching for a certain period of time leads to an equalization of the concentrations of the sputtered components. It was found that to obtain a uniform composition of the mass flow it is necessary to pre-sputter the targets with shielded substrates.

Abstract: The gypsum mortars with different types of aggregate were studied. The surface roughness of fine aggregates and the fracture surface roughness were evaluated by a confocal laser scanning microscopy. Four gypsum mortars and one gypsum paste were tested. The results from the confocal laser scanning microscopy (CLSM) are compared with the pictures of grain surface taken by a scanning electron microscopy (SEM) and both methods seem to be appropriate for surface evaluation. The influence of the surface aggregate roughness on some gypsum mortar properties is demonstrated.

Abstract: The simultaneous combination of optical and magnetic properties of nanoparticles would greatly benefit in vivo disease diagnosis as well as in situ monitoring of cell in cell culture. The most promising application of magnetic particles in biomedicine is MRI contrast enhancement and magnetic hyperthermia. Another important thing is the determination of exact localization of nanoparticles in the cell culture that can be defined by e.g. optical way. In our investigation we used the iron nanoparticles encapsulated in carbon as a magnetic component and carbon quantum dots as an optical labels to provide the photostability and fluorescence in a wide range of wavelengths. In order to avoid the fluorescence quenching in bimodal particles the optical and magnetic components should be separated by insulator layer. To create the optimal bimodal nanoparticles for this purpose the non-typical configuration of nanocomposites was realized, namely, a fluorescent core was separated from the coated magnetic particles by silicon dioxide matrix. Finally, it was shown that these bimodal nanocomposites demonstrate the high magnetic properties, good visualized ability and low toxicity for living cells as well.

Abstract: On 4H-SiC Si-face substrates after H₂ etching, the defect with “line” feature parallel to a step as “bunched-step line” was observed. Using X-ray topography and KOH etching, we confirmed that the bunched-step line originated from basal plane dislocation (BPD). Use of the substrate with the lowest BPD density will be effective to reduce bunched-step line that would affect oxide layer reliability on an epitaxial layer. However, more detail investigation needs to classify the BPD that would become a starting point of bunched-step line.

Abstract: The aim of the study was to validate non-destructive diagnostics of surface of tools and metal sheets after steel grit blasting. We used replicas produced by fy Struers, known under commercial name RepliSet-F5. The replicas were extracted from surfaces of thirty specimens with PVD coatings (CrN, TiCN) and from flat specimens after steel grit blasting. Qualitative and quantitative parameters characteristic of surface morphology were determined by means of an optical profilometer, and confocal microscope was used for surface contactless metrology measurements. We observed a qualitative coincidence of morphological images of original surfaces and replicas. The values of the quantitative parameter Sa (Arithmetic mean height according to ISO 25178) of surfaces and replicas extracted from them differed at the second decimal place. Replicas document well the surface morphology and allow one to obtain information about the state of surface in difficult-to-access sites of the tools or constructions.

Abstract: The aim of this paper is to evaluate the possibility of using the Impact-echo method for assessment of extremely long period of frost resistance of ceramic tiles. Sets of ceramic tiles of the Ia class to EN 14 411 B standard made by manufacture RACOs have been analyzed. The ceramic tiles under investigation have been subjected to 500 freeze-thaw-cycle based degradation in compliance with the relevant EN ISO 10545-12 standard. To verify the correctness of the Impact-echo method results, additional physical properties of the ceramic tiles under test have been measured. To analyze the specimen surface condition, we also used Olympus LEXT 3100 confocal scanning microscope. It has been proved that the acoustic method Impact-echo is a sensitive indicator of the structure condition and can be applied to the ceramic cladding element frost resistance and service life prediction assessment.

Abstract: Cell-biomaterial interactions are strongly affected by topographical and chemical surface characteristics. We found out earlier that geometric titanium (Ti) pillar structures in the micrometer range induce the cells to rearrange their actin cytoskeleton in short fibers solely on the top of the pillars. As a result, cell physiology was hampered concerning collagen I synthesis and spreading capacity. Furthermore, the position-dependent initial cell adhesion strength was declined near the edges. We asked whether these observed cellular effects can be performed only in combination with Ti or occur independently of chemical surface features. In addition, the specific culture conditions, e.g. serum content or influence of gravity, were of interest. Human primary osteoblasts were cultured in Osteoblast Growth Medium with serum containing SupplementMix on pure silicon pillars (5x5x5 μm) or on samples additionally sputtered with Ti (as reference) or gold. To offer the cells ligands for their adhesion receptors, we coated the pillars with collagen I or alternatively with a plasma polymer layer from allylamine. Different from standard culture conditions, the cells were cultured against gravity as well as without serum. The actin cytoskeleton was stained with phalloidin-TRITC after 24 h and analyzed by confocal laser scanning microscopy. Interestingly, on all modifications tested the cell’s actin cytoskeleton was distinctly organized in short fibers on the top of the pillars. Thus, we were able to exclude the influence of (i) the material chemistry (gold, silicon, physical plasma vs. Ti), (ii) the protein deposition on the pillar top and edges, and (iii) the impression caused by gravity.

Abstract: It is proposed in this paper to use phase only liquid crystal spatial light modulators to realize non-mechanical lateral and axial confocal microscopic laser scanning. With a phase only liquid crystal spatial light modulator used as a scanner to realize laser beam deflection, a confocal microscopic lateral beam scanning system is designed. A zoom illuminating lens is formed by incorporating a liquid crystal spatial light modulator along the confocal illumination light path, and thus the focus of the objective lens is axially shifted to realize the axial non-mechanical scanning. The theoretical analyses indicate that phase only liquid crystal spatial light modulators can be used to realize non-mechanical 3D confocal microscopic laser scanning.

Abstract: We have grown epitaxial layers on 2° off-cut 4H-SiC(0001) Si-face substrates. The epitaxial layer surfaces on 2° off-cut substrates are more prone to generate step-bunching than on 4° off-cut substrates, which are observed by confocal microscopy with differential interference contrast. We have speculated that the step-bunching is generated at the beginning of an epitaxial growth. Triangular defect density of epitaxial layers on 2° off-cut substrates is as low as 0.7 cm^–2 for the size corresponding to 150 mm. We have firstly reported distribution of 2° off-cut epitaxial layers for the 150-mm size using two 76.2-mm wafers: σ/mean = 3.3% for thickness, σ/mean = 7.3% for carrier concentration.