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Nucleation of quantum dots
Kulveit, Jan ; Demo, Pavel (advisor) ; Polák, Karel (referee)
Quantum dots are increasingly important in many fields of science. Aminy other methods, quantum dots can also be formed by nucleation processes. In present work we study early stage of nucleation in NaCl and KCl crystals doped with PbCl2. Defect energies of small Pb clusters were calculated using numerical lattice methods. In NaCl-Pb system most stable small clusters have planar structure in {1; 1; 1}Na host lattice plane and intermittent planar phase nucleates. In contrast in KCl-Pb system small clusters with Suzuki phase structure are most stable and Suzuki phase nucleates. Formation of Suzuki phase hinders further transition to stable structure. These results of computer simulation are in agreemend with experimentally observed differences in KCl-Pb and NaCl-Pb systems behavior.
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Nucleation of quantum dots
Kulveit, Jan ; Polák, Karel (referee) ; Demo, Pavel (advisor)
Quantum dots are increasingly important in many fields of science. Aminy other methods, quantum dots can also be formed by nucleation processes. In present work we study early stage of nucleation in NaCl and KCl crystals doped with PbCl2. Defect energies of small Pb clusters were calculated using numerical lattice methods. In NaCl-Pb system most stable small clusters have planar structure in {1; 1; 1}Na host lattice plane and intermittent planar phase nucleates. In contrast in KCl-Pb system small clusters with Suzuki phase structure are most stable and Suzuki phase nucleates. Formation of Suzuki phase hinders further transition to stable structure. These results of computer simulation are in agreemend with experimentally observed differences in KCl-Pb and NaCl-Pb systems behavior.
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Posouzení samočistící schopnosti vodního toku vlivem revitalizačních úprav
Polák, Karel
Rate of pollution degradation in stream depends on its self-purification ability. Intensity of self-purification capacity differs by various streams and except other factors it is notable affected by the character of the watercourse. Due to rugged watercourse, longer detention time and more favorable conditions for resurgence the self-purification capability of restored streams is supposed to be higher than the self-purification capability of technically modified streams. In this thesis the change of water quality indicators in technically modified (923 m) and restored (264 m) reach of Haraska river (South Moravia, the Czech Republic) was investigated. Using QUAL2K software (USEPA, 2008) the water quality model was created. Comparison of changes of water quality indicator values between technically modified and restored reach was also performed (Mann-Whitney-Wilcoxon test, a = 0,05), whereas statistically significant differences were observed only in inorganic and total phosphorus concentration.
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Zkušenosti s vlnovodnými lasery připravenými pulsní laserovou depozicí. (Experience with waveguide lasers fabricated by pulse laser deposition)
Lančok, Ján ; Jelínek, Miroslav ; Jastrabík, Ludvík ; Oswald, J. ; Nikl, Martin ; Polák, Karel ; Studnička, Václav ; Kubelka, J. ; Procházka, S. ; Šimečková, Marta ; Trtík, Vítězslav ; Čtyroký, Jiří ; Skalský, Miroslav ; Chvostová, Dagmar
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