Tough graphs and hamiltonian circuits

AbstractThe toughness of a graph G is defined as the largest real number t such that deletion of any s points from G results in a graph which is either connected or else has at most s/t components. Clearly, every hamiltonian graph is 1-tough. Conversely, we conjecture that for some t0, every t0-tough graph is hamiltonian. Since a square of a k-connected graph is always k-tough, a proof of this conjecture with t0 = 2 would imply Fleischner's theorem (the square of a block is hamiltonian). We construct an infinite family of (32)-tough nonhamiltonian graphs

Examination of Montanol 551-Flotation Agent at Coal Flotation in Paskov Coal Cleaning Plant

Import 29/09/2010Předložená práce se zabývá popisem technologie úpravy černého uhlí, přičemž se zaměřuje na technologický proces flotace. Dále je popsán způsob úpravy na úpravně uhlí Dolu Paskov. Z tohoto provozu odebrané vzorky surového kalu byly podrobeny flotačním testům v laboratořích VŠB-TU Ostrava. Cílem testů bylo porovnat používaná flotační činidla. V práci jsou statisticky zpracované výsledky flotačních testů a také posouzení vlivu spotřeby činidel na ekonomickou stránku procesu úpravy.The presented thesis deals with description of technology of coal modification, focusing on the technological process of flotation. There is also described the method of modification in the coal cleaning plant Paskov. The samples of raw sludge taken from this production unit were subjected to the flotation tests in the laboratories of VŠB – TU Ostrava. The aim of the tests was to compare the flotation reagents which were used. In the thesis the results of floating tests are statistically processed and there is also assessed the impact of the consumption of reagents on the economies of the editing process.Prezenční542 - Institut hornického inženýrství a bezpečnostivýborn

Transport and Noise Characteristics of MOSFET Transistors

Dizertační práce je zaměřená na analýzu transportních charakteristik v submikronových a mikronových tranzistorech MOSFET. Na základě předpokladu, že gradient divergence proudové hustoty v kanálu je nulový, je odvozena ampér-voltová charakteristika tranzistoru MOSFET a provedeno experimentální sledování závislosti proudu kanálu na napětí kolektoru pro řadu vzorků s různými rozměry kanálu v širokém teplotním rozsahu od 10 do 350 K. Navržený fyzikální model umožnil určit hodnotu přívodních odporů k emitoru a kolektoru a jejich teplotní závislost. Z analýzy transportních charakteristik se získají informace o koncentraci nosičů náboje v kanálu a poloze Fermiho hladiny v místě aktivní pasti, která je zdrojem RTS šumu. Určení koncentrace nosičů náboje a polohy Fermiho hladiny je důležité z toho důvodu, že tyto veličiny určují intenzity kvantových přechodů a jejich hodnoty nejsou po celé délce kanálu stejné. Z analýzy charakteristik RTS šumu bylo experimentálně dokázáno, že koncentrace v daném místě kanálu klesá s rostoucím proudem při konstantním napětí na hradle a proměnném napětí na kolektoru. Dále byla určena poloha aktivních pastí RTS šumu a bylo zjištěno, že se nachází v blízkosti kolektoru. Aktivní past se nachází v místě, kde splývá Fermiho hladina z energetickou hladinou pastí.This doctoral thesis is focused on the analysis of transport characteristics of submicron and micron transistors MOSFET. The assumption is a constant gradient of concentration, which leads to the fact that the diffusion current density is independent of the distance from the source. Active energy was determined from temperature dependence. The proposed physical model made it possible to determine the value of access resistance between drain and source their temperature dependence. Based on the assumption that the divergence of the gradient of the current density in the channel is zero. IV characteristics of the transistor MOSFET are derived and conducted experimental monitoring current channel depending on the collector voltage for the series of samples with different channel lengths in a wide temperature range from 10 to 350 K. Information on the concentration of charge transport in the channel and the position of the Fermi level at the point of active trap, which is the source of RTS noise, is obtained from the analysis of the transport characteristics. Determining the concentration of charge transport and the position of the Fermi level is important because these variables determine the intensity of quantum transitions and their values are not the same throughout the length of the channel. It was experimentally proved from the analysis of the characteristics of RTS noise that concentration at the local channel decreases with increasing current at a constant voltage on the gate and a variable voltage at the collector. Further, the position of active traps of RTS noise was intended and it was found that this is located near the collector. Active trap is located at the point where the Fermi level coincides with energy level of the traps.

Asymptotically almost periodic solutions of limit and almost periodic linear difference systems

In this paper, limit periodic and almost periodic homogeneous linear difference systems are considered. We study the systems in which the coefficient matrices are taken from a given bounded group and the elements of the matrices are from an infinite field with an absolute value. We show a condition on limit periodic and almost periodic systems which ensures, that the considered systems can be transformed into new systems having certain properties. The new systems possess non-asymptotically almost periodic solutions. The transformation can be done by arbitrarily small changes