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Ice and its impurities from the perspectives of photochemistry and electron microscopy
Heger, D. ; Krausko, J. ; Klán, P. ; Runštuk, Jiří ; Neděla, Vilém
Ice as a solid phase of water is an interesting but still not well understood medium. Our photochemical group utilized chemical and spectroscopic tools to acquire information relevant to the environmental and applied science. In the introduction I would like to stress some important facts on ice and frozen aqueous solutions stemmed from our work. Still opened question, that we are trying to answer by the ESEM, is where and at what forms are the impurities located after the freezing. The recently published results from the pilot collaboration with Dr. Neděla’s group will be detailed.
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Using environmental scanning electron microscopy (ESEM) as a non-invasive method to studying fixed parasites
Mašová, Šárka ; Neděla, Vilém ; Tihlaříková, Eva
Scanning electron microscopy (SEM) is popular and for taxonomy of parasites very important and not substituted method in many times. However sometimes taxonomists have only one specimen and cannot use classical SEM, because their sample (poor conductor) have to be fixed, dehydrated and coated before it can be observed. This method condemns samples for destroying and do not allow other using of it, e.g. for molecular study or depositing as type material in museum. Moreover, the specimen preparation is often long and slow. Environmental scanning electron microscopy (ESEM) brings two main advantages: elimination of speed of sample preparation and non-invasivity.
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The Study of Ice Impurities Using the Environmental Scanning Electron Microscopy at Higher Pressures and Temperatures
Neděla, Vilém ; Runštuk, Jiří ; Klán, P. ; Heger, D.
Natural ice and snow accumulate and concentrate significant amounts of impurities that can be stored or chemically transformed, and eventually released to the environment. The location of impurities and their interactions with the water molecules of ice have not yet been sufficiently clarified. The aim of this work is to observe an uranyl-salt brine layer on the ice surface using a back scattered electron detection and the ice surface morphology using a secondary electron detection under equilibrium conditions in a specimen chamber of environmental scanning electron microscope (ESEM). Our specially modified ESEM AQUASEM II equipped with the YAG:Ce3+ backscattered electron detector, an ionization detector of secondary electrons, a special hydration system and a Peltier cooled stage was used. The pressures between 400-700 Pa, 50% water-vapor saturation, and the temperatures above 250 K were utilized in our experiments. At these conditions, the phenomena of etching and subsequent stripping of impurities are largely suppressed.
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Workshop of Interesting Topics of SEM and ESEM
Neděla, Vilém ; Mašová, Šárka ; Tihlaříková, Eva
The book of abstracts from the Workshop of Interesting Topics of SEM and ESEM includes original English written papers focused on new results of Environmental electron microscopy group from the ISI ASCR in Brno ant scientific and industry partners of this group. This book contain new results from the field of instrumentation, biology, physics and chemistry. The overall objectives of the workshop were to provide space for exchanging news, ideas, advice and experience in the field of Electron Microscopy which can lead to mutual future scientific collaboration. This workshop has been organized as a forum of state-of-the-art discussion in a number of topics which will be covered by several distinguished invited talks and other presentations.
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Rastrovací elektronová mikroskopie mokrých vzorků syntetických polymerů
Šlouf, Miroslav ; Studenovská, Hana ; Rypáček, František ; Sikora, Antonín
Syntetické polymery s vysokým obsahem vody (mokré syntetické polymery, hydrogely) se často používají jako umělé tkáně. Studium jejich 3D struktury pomocí elektronové mikroskopie je velmi obtížné: ve standardním elektronovém mikroskopu se totiž voda ze vzorku téměř okamžitě odpaří a jeho struktura se zhroutí. Nicméně je možno strukturu hydrogelů pozorovat pomocí specielních technik, jako je mrazová nízkovakuová rastrovací elektronová mikroskopie (cryoLVSEM) a environmenální rastrovací elektronová mikroskopie (ESEM). Tyto dvě techniky jsou v příspěvku popsány a porovnány.
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