National Repository of Grey Literature 6 records found  Search took 0.00 seconds. 
Dynamics of delocalized states in molecular systems studied by time-resolved THz spectroscopy
Mics, Zoltán ; Kužel, Petr (advisor) ; Jepsen, Peter Uhd (referee) ; Kůsová, Kateřina (referee)
This thesis is devoted to a study of the conductivity of confined charge carriers in various nanocrystalline materials. The experimental method -- THz spectroscopy -- involves measurements of the conductivity of carriers generated by doping or by optical excitation. In the theoretical interpretation of measured data we address important aspects of carrier transport, connected to the microscopic inhomogeneity of samples and the nanoscale confinement of carriers. We focus on the study of nanocrystalline ZnO and CdS using simulations and experiments in a wide range of carrier densities and for several temperatures. In ZnO, the interplay of highly mobile electron-hole gas, dense electron-hole plasma and population of excitons was observed. In CdS the investigation reveals the importance of clusters of nanocrystals in the electron confinement. The dynamics of the electron mobility at different carrier densities show the role of the kinetic energy of electrons and its relaxation in the carrier transport in nanostructured systems. At temperatures 20 K and at low carrier densities a crossover between localized transport and Drude-like free electron behaviour was observed for the first time.
Light Emission from Materials Based on Silicon
Kůsová, Kateřina
New characterization techniques based on the use of local luminescence probes enable to study the properties of various nanostructures for optoelectronic applications with high (nanometric) spatial resolution. An experimental setup for measuring by one of these methods, namely, the photon emission induced with the tip of a scanning tunnelling microscope (PESTM), has been built.In the future, this setup will be used for studying the luminescence from individual silicon nanocrystals in contrast to traditional macroscopic measurements providing only the information on the light emission from a large number of nanocrystals. Nanocrystalline silicon is a promising material in which the light emission is enhanced, in contrast to monocrystalline silicon, by quantum connement.Optoelectronic properties of two series of samples containing this interesting material were measured.Firstly, a weak electroluminescence signal and reasonable transport properties of samples prepared by embedding electrochemically etched silicon nanocrystals into SiO2 matrix, and secondly, a conductive path created between individual silicon nanocrystals implanted in a silica glass slab were observed.Besides, for the latter series of samples, an interference model was developed and used to describe their structure. All these results are...
Optically and electronically active diamond-silicon photonic structures: state and outlooks
Ondič, Lukáš ; Dohnalová, Kateřina ; Kůsová, Kateřina ; Cibulka, Ondřej ; Ledinský, Martin ; Babchenko, Oleg ; Kromka, Alexander ; Rezek, Bohuslav ; Pelant, Ivan
We have prepared the photonic crystal at the top of the nanocrystalline diamond layer. We have obtained the effective extraction of diamond intrinsic photoluminescence via leaky modes. We have shown the simulation of optical gain enhancement in the photonic crystal.
The relationship between a mother and the child in the early developmental stages in the educational institution for juvenile mothers with children
KŮSOVÁ, Kateřina
This thesis deals with the relation between a mother and a child in early development stages in an educational institute for minor mothers with children. A mother is the most important person for a child, in whom it finds the feeling of safety and love. Children, who are with their mothers in an institution for any reason need to experience these feelings the more intensely. The theoretical part is focused on development of a child in early development stages and on the importance of mother?s approach. I present a chapter dealing with the approach to pregnancy in various cultures in the thesis for comparison. Another chapter is focused on pregnancy and motherhood of teenage girls. The last chapter pays attention to the legislation specification of institutional upbringing and the present state of the care of minor mothers and their children in educational institutions. The practical part is focused on description of relation of real minor mothers and their children in an educational institution where I had my long-term practical training. The research was based on narrative interviews with seven minor mothers with ordered institutional upbringing. Additional information was gained by secondary analysis of the data from the social documentation of the respondents. I set two goals. The first goal was to capture the relation of a minor mother and her child in an educational institution for mothers with children. The mother-child relation is not formed in an optimum and common way. My conception of relation between a mother and a child in the environment of an educational institution was confirmed. The girls are not sufficiently mentally and physically mature for upbringing and the environment they are in is another substantial determinant forming the relation to the child. The mother?s primary environment, which is very often not ideal, also plays an important role. The second goal is closely linked to the first one. It deals with the causes of locating an adolescent mother in an institution. The respondents had been ordered institutional upbringing already before pregnancy for behaviour disorders or they were relocated to the institution during pregnancy from an environment that threatened their children. The minor mothers located in an institution mostly have bad family background and a behaviour disorder. The problems of minor mothers located in an educational institution have in some instances their roots in family relations and the environment they grew up. Their families may belong to a group of families with low social status. From the point of view of a minor mother and her child primary prevention already in childhood of a potential minor mother is important. High quality staff able to provide a mother and a child with optimum care and quality conditions for creation of the relation between them is necessary for the educational institutions for mothers with children. A mother should be given more space and time to create a relation with her child in an educational institution. Another important change should be made in maternity wards. A mother should get her child into her arms immediately after birth so as the bonding of the mother to her child may be created. The influence of the primary family as well as overall influence of our society on the minor mother also play important roles here.

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3 KŮSOVÁ, Kateřina
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