National Repository of Grey Literature 11 records found  1 - 10next  jump to record: Search took 0.01 seconds. 
Full centroid molecular dynamics through machine learning
Crhán, Martin ; Maršálek, Ondřej (advisor) ; Slavíček, Petr (referee)
This thesis is concerned with developing new methodology for the more effi- cient execution of centroid molecular dynamics simulations - a method based on the theory of imaginary-time path integrals, commonly used in accurate com- putational prediction of vibrational spectra and other dynamical properties of condensed-phase molecular systems. This is done through the use of machine learning methods to explicitly construct the potential for the centroid. The results obtained through the new methodology are subsequently systematically compared with results obtained through the older, adiabatic, approach to cen- troid molecular dynamics. This is done for a range of low-dimensional model systems as well as realistic highly-dimensional molecular systems. The differ- ences in these results and the advantages of the new approach are subsequently discussed. The properties of the potential which has been constructed have also been investigated. 1
The study of the association behavior of the amphiphilic copolymers in solutions containing low molar compounds by means of computer simulations.
Šindelka, Karel ; Limpouchová, Zuzana (advisor) ; Slavíček, Petr (referee) ; Vondrášek, Jiří (referee)
Title: The study of the association behaviour of the amphiphilic copolymers in solutions containing low molar compounds by means of computer simulations. Author: Mgr. Karel Šindelka Department: Faculty of Science, Charles University Supervisor: Doc. Ing. Zuzana Limpouchová, Csc. Abstract This doctoral thesis focuses on the study of electrostatic self- and co-assembly in complex polymer solutions containing polyelectrolyte (PE) block copolymers together with surfactants, neutral homopolymers, or oppositely charged PEs using the dissipative particle dynamics (DPD). It was shown that the electro- static self-assembly depends not only on the cooperative interactions of oppo- sitely charged PE chains, but also on the amphiphilicity of PE species or on the polymer block compatibility, among other properties. PEs with incompatible blocks create well-defined core-shell structures, while large ill-defined crew-cut aggregates form from PEs with compatible blocks In non-stoichiometric mixtures of PEs with incompatible blocks, co-assembled nanoparticles are smaller than in stoichiometric mixtures and are charged. The destabilization of larger aggregates depends on how the PE charge surplus is introduced: the effect is strongest when the density of the surplus PE charge on the PE chains is increased and weakest when the...
The study of the association behavior of the amphiphilic copolymers in solutions containing low molar compounds by means of computer simulations.
Šindelka, Karel ; Limpouchová, Zuzana (advisor) ; Slavíček, Petr (referee) ; Vondrášek, Jiří (referee)
Title: The study of the association behaviour of the amphiphilic copolymers in solutions containing low molar compounds by means of computer simulations. Author: Mgr. Karel Šindelka Department: Faculty of Science, Charles University Supervisor: Doc. Ing. Zuzana Limpouchová, Csc. Abstract This doctoral thesis focuses on the study of electrostatic self- and co-assembly in complex polymer solutions containing polyelectrolyte (PE) block copolymers together with surfactants, neutral homopolymers, or oppositely charged PEs using the dissipative particle dynamics (DPD). It was shown that the electro- static self-assembly depends not only on the cooperative interactions of oppo- sitely charged PE chains, but also on the amphiphilicity of PE species or on the polymer block compatibility, among other properties. PEs with incompatible blocks create well-defined core-shell structures, while large ill-defined crew-cut aggregates form from PEs with compatible blocks In non-stoichiometric mixtures of PEs with incompatible blocks, co-assembled nanoparticles are smaller than in stoichiometric mixtures and are charged. The destabilization of larger aggregates depends on how the PE charge surplus is introduced: the effect is strongest when the density of the surplus PE charge on the PE chains is increased and weakest when the...
Theoretical study of spin-orbit coupling on spectra and photophysics of rhenium complexes
Heydová, Radka ; Záliš, Stanislav (advisor) ; Slavíček, Petr (referee) ; Srnec, Martin (referee)
Title: Theoretical study of spin-orbit coupling on spectra and photophysics of rhenium complexes Author: RNDr. Radka Heydová Department: Physical and Macromolecular Chemistry Supervisor: Ing. Stanislav Záliš, CSc., JHI AS CR, v.v.i. Supervisor's e-mail address: stanislav.zalis@jh.inst-cas.cz Abstract: Relativistic effects, especially spin-orbit coupling (SOC), play an essential role in transition metal chemistry and SOC treatment is indispensable for a correct theoretical description. To demonstrate the importance of SOC, the energies and oscillator strengths of vertical transitions for a series of [ReX(CO)3(2,2'-bipyridine)] (X = Cl, Br, I) and [Re(imidazole)(CO)3(1,10-phenanthroline)]+ complexes were calculated in the spin-free (SF) and spin-orbit (SO) conceptual frameworks. Two different computational approaches were adopted: SO-MS-CASPT2 where SOC was added a posteriori using a configuration interaction model (SO-RASSI), and the approximate perturbative SO-TD-DFT method. Relativistic effects were included via the two-component Douglas-Kroll-Hess transformation and the zeroth-order regular approximation in the former and the latter technique, respectively. The SF (i.e. accounting only for the scalar relativistic effects) and SO results from both methods were compared with each other and to available...
Quantum mechanical study of the electron hoping processes of pigments from photosystems. Simulation of absorption and emission photoelectron spectra.
Cajzl, Radim ; Burda, Jaroslav (advisor) ; Slavíček, Petr (referee)
Title: Quantum mechanical study of the electron hoping processes of pig- ments from photosystems. Simulation of absorption and emission photoelectron spectra. Author: Bc. Radim Cajzl Department: Department of Chemical Physics and Optics Supervisor: prof. RNDr. Ing. Jaroslav Burda, DrSc., Department of Chemical Physics and Optics Abstract: The aim of this thesis is to develop a methodology for simulation of dynamical properties of carotenoids by OMx method combined with surface electron hopping. We use linear conjugated polyenes: ethene, butadiene, hexa- triene up to polyenes with 22 carbon atoms as model systems. First, the spectra are calculated with sufficiently good agreement with the experimental data by both correct order of excited states and small deviation from experimental data. These results are used for electron surface hopping for calculation of mean lifetimes of excited states of studied polyenes. Calculated lifetimes are of the same order as experimental data for butadiene, hexatriene and octatetraene. Calculated lifetimes for poleynes with 20 resp. 22 carbon atoms agree well with chemically analogous carotenoids. Keywords: quantum mechanics, photoelectron spectra, pigments of photosys- tems, elecrton transitions, molecular and electronic dynamics
Miracles of Czech Medieval Saints
Slavíček, Petr ; Kubín, Petr (advisor) ; Doležalová, Eva (referee)
The present work focuses on miracles of Czech saints in the period of the early Middle Ages. In the introductory part, the concepts of sanctity and miracles and their development throughout the history are elucidated. Criteria for selecting the saints included in the work are then discussed. The work is dominantly based on hagiographic resources, yet medieval chronicles and canonization acts are also included. The main part of the work is a catalogue of miracles attributed to Czech medieval saints, particularly St. Ludmila, St. Wenceslas, St. Adalbert, St. Procopius, St. Agnes, St. Guntherus and beatific Hroznata. For each saint, both the legendary and historical lives are briefly described and the resources used are discussed. The anthology of miracles is then presented, using critical editions of the legends. The miracles attributed to the particular saints are analyzed in the context of analogical miracles in previous periods or other saints. The role of miracles in medieval society is discussed as well.
Vizualizace kvantové kryptografie
Slavíček, Petr
Document proposes possibilities of visualization in quantum cryptography and its implementation in educational application. Describes in detail the basic principles of quantum cryptography and the way of transformation into application that should be teaching tool for its users. Tells about its development phase and about chosen methods. Describes problems that appeared during programming and their solutions. Compares this application with reality and others implementations. Provides ideas for further expansion.

National Repository of Grey Literature : 11 records found   1 - 10next  jump to record:
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1 Slavíček, Pavel
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