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Propustnost podél hranic zrn v dobře definovaných polykrystalických vrstvách silikalitu-1 a v samostatných krystalech
Brabec, Libor ; Zikánová, Arlette ; Kočiřík, Milan
Self-supporting silicalite-1 layers were grown on mercury surface from clear solutions at temperatures 140-180 oC. Large silicalite-1 crystals were synthesized using TPABr as template. Layer morphology and thickness were characterized by SEM. Phase purity of silicalite-1 and orientation of crystals were determined by XRD. Layers with the thickness > 40 .mu.m were found to be highly compact. Wet HF etching of as-synthesized polycrystalline silicalite-1 layers caused formation of deep sharp slits at grain boundaries and thus it visualized them. Contrary to this result etching of calcined layers led to a kind of a negative image represented by preserved thin shells at crystal boundaries which were found to be impregnated by carbon residues formed during template removal. Results of etching experiments give a strong indication of the existence of a thin amorphous silica interface between neighbouring crystals. The etching patterns were somewhat different for large silicalite-1 crystals.
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Ink Films from Carbon Powders on Conventional Solid Electrodes as Alternative Disposable Sensors
Josypčuk, Bohdan ; Barek, J. ; Novotný, Ladislav
Rozšíření rozsahu pracovních potenciálů pevných elektrod bylo docíleno jejich pokrytím filmem z polymeru obsahujícího vodivé částice (grafitu, skelného uhlíku, nanotub aj.). Takový film může obsahovat 70 - 90% skelného uhlíku a 30 - 10% polystyrenu (procenta hmotnostní). Film se 70 % skelného uhlíku se chová více jako soubor mikroelektrod; s 90 % - spíše jako klasická elektroda ze skelného uhlíku. S takovým filmem lze pracovat i celý den; pro odstranění filmu stačí otřít ho o filtrační papír. Pro oxidaci ferocenu, adeninu, guaninu a jiných látek byly použity filmy s různým obsahem skelného uhlíku na podložkách ze stříbrného pevného amalgamu, zlata a platiny.
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Development and Application of Thyristor IGCT
Bureš, J. ; Homola, J. ; Jehlička, Vladimír ; Kalčík, K.
The development of the power switching device IGCT in the Co. Polovodiče, Inc., principle of operation of the device, practical design of an IGCT chopper for feeding a traction motor, the device parameters. The development of an inverter with IGCTs in Institute of Electrical Eng. of Academy of Sciences of the Czech Rep. destined for means of transport driven by an induction motor.
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Czech Mayors on problems of the territorial public adminstration
Vajdová, Zdenka ; Illner, Michal
Results of the research äPolitical leaders of the European towns' (survey of the Mayors of the towns of the10 th. and more inhabitants), related to municipality and region cooperation, to the Mayors attitudes to the public administration reform and decentralisation. Information about attitudes of Mayors following from the analysis of the published Mayorsž opinions on public administration reform realization.
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