|
|
Coating methods for cutting tools
Doležal, Jan ; Madaj, Martin (referee) ; Humár, Anton (advisor)
Bachelor work describes methods of coating of cutting tools and their technical characteristics. The work is given below the current product range of manufacturers of coated cemented carbides. At the end of this work is treated the development of coating cutting tools and types of applied coatings.
|
|
|
Carbon Based Materials
Hrazdíra, Matěj ; Čelko, Ladislav (referee) ; Klakurková, Lenka (advisor)
The proposed bachelor thesis deals with carbon based materials. First of all, an overview of its allotropic modifications including newly discovered forms, conditions of their existence and also their basic properties is shown. Further the extraction of carbon materials is briefly introduced. In the next chapters, forms of carbon are classified and particularly described individually with respect to manufacturing technologies and further applications. Individual chapters are dedicated to synthetic carbon and graphite, carbon fibers and carbon fiber reinforced composites. Manufacturing processes of synthetic carbon and graphite, involving possible precursors, are described in detail together with their use in various engineering applications. The following part is dedicated to carbon fibers, in particular to the manufacturing process based on the precursor used including surface treatment and sizing. Additionally the use of virgin carbon fibers is also described. The last part is focused on carbon fiber reinforced composites. Firstly possible distributions of carbon fibers in a matrix are described. Then the technology of manufacturing, properties and use of single composites according to the matrix material are expounded.
|
|
|
Creating Methodology for Independent Verification of Monitor Unit Calculation for Department of Oncology at Hospital Ceske Budejovice
ADENSAMOVÁ, Jana
The Bachelor's thesis deals with the planning of radiotherapy in general and with planning systems which are used at the Department of Oncology of České Budějovice Hospital, a.s. A planning system is a software that is used to calculate the dose distribution of each beamlet in patients and critical organs. Currently, České Budějovice Hospital uses the Eclipse planning system by Varian. The thesis is divided into a theoretical and a practical part. The theoretical part is divided into five chapters, which briefly summarizes knowledge on radiotherapy, the planning of radiotherapy, and planning systems. In the Eclipse system, I describe particularly the algorithms and their use. The description of the DIAMOND software covers mainly the control of MU and doses in plans generated by the Eclipse program. The main goal of the thesis was to develop a methodology for an independent verification of the calculation of monitor units and to determine the allowable deviations. The practical part of the thesis deals primarily with the development of the methodology of working in the DIAMOND program and the verification of radiotherapy plans generated by the Eclipse system. The chapter 'Results' offers a scheme for the calculation of MU and doses in the DIAMOND program. It describes individual steps which should be followed in order to allow for verification. Furthermore, it presents a table with results of the verification of the plan for tangential field technique in the irradiation of breast cancer. Other tables list the doses calculated by the Eclipse planning system and the DIAMOND program for IMRT technique (Intensity Modulated Radiation Therapy) in the irradiation of prostate cancer. In the technique of two tangential fields, deviations of MU were calculated between the calculations made by the Eclipse planning system and those generated by the DIAMOND software. In the IMRT technique with seven fields (5 whole fields + 2 split fields), doses deviations were defined during the calculation of the irradiation plan. The technique of seven fields (5+2) was chosen because of the simplicity of calculation. The question remains whether an independent calculation of monitor units will help to eliminate gross errors in the calculation of irradiation plans.
|
|
|
Konkurenceschopnost Číny ve 21. století: Analýza čínského lidského kapitálu
Dvořáková, Markéta ; Stuchlíková, Zuzana (advisor) ; Hnát, Pavel (referee)
The diploma thesis aims to discourse how China´s competitiveness has developed in the 21st century, with a special focus on human capital as one of the key factors of production that greatly fosters competitive advantage. The first chapter builds up a theoretical framework for the research part of the thesis. It reviews the concepts of competitiveness, Michael Porter´s diamond, and the theory of human capital. The second chapter examines trends and challenges of China´s competitive advantage according to Michael Porter´s diamond model. The third chapter evaluates the development of China´s human capital, its cultivation, current state, and surveys the generation Y´s attitudes to human capital.
|
|
|
In situ XPS characterization of diamond films after AR.sup.+./sup. cluster ion beam sputtering
Artemenko, Anna ; Babchenko, Oleg ; Kozak, Halyna ; Ukraintsev, Egor ; Ižák, Tibor ; Romanyuk, Olexandr ; Potocký, Štěpán ; Kromka, Alexander
In this work, in situ XPS analysis of chemical composition of H- and O-terminated nano- and microcrystalline diamond (NCD and MCD) films before and after their sputtering by the Ar+ cluster ion beam was investigated. Scanning electron microscopy confirmed sputtering of all diamond surfaces with a rate about 0.5 nm/min. Raman spectroscopy and XPS revealed surface graphitization of diamond surface induced by sputtering. Moreover, XPS data showed the presence of about 0.7 % of Ar atoms on the investigated diamond surface after 66 min of sputtering. Also, oxygen residuals were still presented on the H-NCD surface after 66 min of sputtering. In contrast, no oxygen was found on the H-MCD surface just after 2 min of sputtering. Surface composition is discussed in respect to the diamond films growth parameters and surface structure.
|
|
|
Hydrogen-terminated diamond surface as gas sensing layer working at room temperature
Davydova, Marina ; Kulha, P. ; Babchenko, Oleg ; Kromka, Alexander
Effect of fluorine- and hydrogen-terminated diamond surface on the gas sensing properties at room temperature was investigated. The gas sensing properties diamond-based sensor were measured by the changes of electrical resistance to various volatile organic compounds (C6H6, C3H6O, isopropylalcohol) and relative humidity. The comparative sensing performance of hydrogenated diamond surface shows improvement in sensitivity toward benzene, acetone, isopropylalcohol and humid air in contrast to fluorinated diamond surface, where the surface conductivity was suppressed.
|
|
|
International diamond trade
Bajerová, Jitka ; Štěrbová, Ludmila (advisor) ; Richter, Stanislav (referee)
The thesis deals with the international diamond trade. It describes diamond as a unique commodity, which is a subject of interest of collectors and investors. The first part is focused on a general characteristic and an international evaluation of diamonds; next part presents world deposits and describes mining and processing of diamonds. The main part is devoted to trading with diamonds. This part presents the diamond market, its main players, places and volume of trade. The final part refers to conflict diamonds and the consequential Kimberley Process and other control measures when dealing with diamonds.
|
|
|
Comparativ study on functionalization of NCD films with amine groups
Artemenko, Anna ; Kozak, Halyna ; Stuchlík, Jiří ; Biederman, H. ; Kromka, Alexander
Nanocrystalline diamond (NCD) films are considered as highly attractive material for biosensing due to its unique semiconducting properties. This can be achieved by modification of NCD films surface on molecular level. Typically chemical immobilization of biomoleculs requires the presence of active functional groups on the diamond surface. This was achieved by attachment of -NH2 functional groups on the surface of H- or O-terminated NCD surface via two plasma-based processes. The first process, deposition of thin amine containing polymer by RF magnetron sputtering of Nylon target in Ar/N2 gas mixture. The second process employs RF plasma treatment in NH3 for 10 minutes. Chemical derivatization (CD) XPS analysis revealed that polymeric coating exhibits a higher amount of amino groups than the diamond surface treated in NH3 RF plasma. Results of I-V measurements showed that surface conductivity of H-terminated NCD films was preserved only after the RF sputtering.
|
|
|
Growth of diamond thin films: a review
Kromka, Alexander ; Potocký, Štěpán ; Rezek, Bohuslav
Diamond is shown as an extraordinary material which offers promising solution for variety of fundamental studies and industrial uses. Here, growth of synthetic diamond films at low pressures (1 atm) and low temperatures (<1000°C) from carbon consisting gas mixtures is discussed. Variety of chemical vapor deposition techniques are reviewed, their advantages and disadvantages are pointed out too.
|
|
|
Diamond chemical vapor deposition
Kromka, Alexander
Present paper reviews growth of diamond thin films by various chemical vapor deposition processes. Basic characteristics and common features of processes are pointed out with a respect to quality of grown films and standard process parameters. Novel and non-standard diamond syntheses techniques are briefly discussed.
|
guest ::
