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Rastrovací elektronová mikroskopie mokrých vzorků syntetických polymerů
Šlouf, Miroslav ; Studenovská, Hana ; Rypáček, František ; Sikora, Antonín
Synthetic polymers with high content of water (wet synthetic polymers,hydrogels) are frequently used in tissue engineering. Investigation of their 3D-structure by means of scanning electron microscopy is very difficult: in a standard electron microscope water almost immediately evaporates and the structure breaks down. Nevertheless, hydrogels morphology can be visualised by means of low-vacuum scanning electron microscopy in cryo conditions (cryoLVSEM) and by environmental scanning electron microscopy (ESEM). The two techniques are described and compared.
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Studium dimerů molekulárními můstky spojených stříbrných nanočástic pomocí metody SERS
Šmejkal, P. ; Vlčková, B. ; Moskovits, M. ; Pavel, I. ; Sládková, M. ; Pavlova, Ewa ; Šlouf, Miroslav
The ability of several molecules to act as linkers for Ag nanoparticles was tested. As new prospective linker molecules, dimercaptocarborane, ethidium bromide and 5,10,15,20-tetrakis(4-sulphonatophenyl)porphine (TSPP) were selected owing to their terminal functional groups, which can assemble the Ag nanoparticles together to form a dimer.
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Změny velikostí zlatých nanočástic vysokoenergetickými laserovými pulsy
Dammer, Ondřej ; Pfleger, Jiří ; Šlouf, Miroslav ; Vlčková, B.
We focused on the interaction of gold nanoparticles of various mean size embedded in aqueous environment with nanosecond pulsed laser irradiation of various energy per pulse at wavelength 355 and 532 nm, respectively. We performed a sequence of in-situ surface plasmon extinction (SPE) measurements of the fragmented hydrosol as well as ex-situ TEM studies to evaluate the size distribution of resulting Au nanoparticles. It was found that laser pulses of 355 nm wavelength provide smaller nanoparticles compared with 532 nm pulses at the same absorbed energy.
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Srovnání časově fluktujících SERS signálů dimerů porfyrinem spojených nanočástic stříbra s malými agregáty, připravenými ve vodním a organickém prostředí
Vlčková, B. ; Moskovits, M. ; Sládková, M. ; Pavel, I. ; Šlouf, Miroslav ; Šišková, K.
Formation of 5,10,15,20-tetrakis(4-aminophenyl)porphine -bridged dimers and small aggregates of Ag nanoparticles capped by pentylamine and/or citrate was established by SEM and TEM respectively. From both samples, temporally fluctuating SERS signals were obtained.
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Charge densities and topological analysis
Šlouf, Miroslav
Lecture compares conventional X-ray diffraction analysis on single crystals with more precise techniques based on kappa-refinement and multipole refinement. The results that can be obtained from precise charge denstity studies and topological analysis are listed. Examples taken from practice show how to calculate atomic charges, double-bond characters etc. from both experimental X-ray data and theoretical quantum chemistry calculations.
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