Possibility of using polycrystalline diamond in a medicine

katedra: KMT; přílohy: 1 CD ROM; rozsah: 65 s.The subject of the thesis for Masters is microfluidic devices, which are shown in the theoretical part. The devices have been charekterisaes the properties of natural diamond compering to imitation diamond and produced by technique CVD (Chemical Vapour Deposition). There is also a written description of the process of the creating polycrystalline and the grained diamond by MPCVD (Micro Wave Chemical Vapor Deposition) which were part of experiments which took place. It was proven during practical parts of experiments that they were useful in these kind of devices. By these experiments the measurements, figures and the way they make it is known. These figures have been described numericly, graphicly and there was also a discussion about them in detail.Diplomová práce je věnována tématice mikroprůtokových zařízení. Tyto byly představeny v teoretické části. Byly v ní charakterizovány vlastnosti přírodního diamantu ve srovnání s umělým diamantem, vytvořeným za použití technik CVD. Byl také popsán proces polykrystalického vznikání hrubozrnného diamantu vytvářeného metodou MPCVD, na kterém byly provedeny výzkumy. V praktické části byla představena řada experimentů, které charakterizovaly vlastnosti tohoto materiálu a určily jeho použitelnost pro takovéto zařízení. Byla popsána metodika měření výzkumů, získané údaje, způsob jejich obdržení. Tyto výsledky byly zpracovány číselně a graficky, byla také uskutečněná diskuse výsledků

Biogenic silicon dioxide nanoparticles processed from natural sources

The main purpose of this study is to obtain the biogenic silica nanoparticles from selected types of plants and thorough characterization. Plants create SiO2 nanoparticles while growing from the colloidal solution of orthosilicic acid contained in the soil. Together with acid, they absorb additional ions that are essential for their growth, which was found using SEM and EDX analysis. The organic part of the plants was removed using a two-step method. Firstly, the plants were purified in 10% HCl in order to remove undesirable ions. Next, the optimal degradation temperatures were determined according to TGA results that varies between 500-650 degrees C. After the above-mentioned processes silica was studied using ICP-OES, FTIR, TEM, and N-2 adsorption. The nanoparticles obtained from the investigated kinds of plants showed an amorphous structure, differed in size (from 8 to 20 nm) and are not purely symmetrical in any of the investigated samples. Estimated content of SiO2 nanoparticles was in the range 11.5-25.3% depending on the sample. The specific surface area was measured using the BET method