|
|
Functional Tungsten-based thin films and their characterization
Košelová, Zuzana ; Horáková, L. ; Sobola, Dinara ; Burda, Daniel ; Knápek, Alexandr ; Fohlerová, Z.
Anodizing is a technique by which thin oxide layers can be formed on a surface. Thin oxide layers have been found to be useful in a variety of applications, including emitters of electrons. Tungsten is still a common choice for cold field emitters in commercial microscopy applications. Its suitable quality can be further improved by thin film deposition. Not only the emission characteristic can be improved, but also the emitter operating time can be extended. Tungsten oxide is known for its excellent resistance to corrosion and chemical attack due to its stable crystal structure and strong chemical bonds between tungsten and oxygen atoms. Many techniques with different advantages and disadvantages have been used for this purpose. Anodization was chosen for this work because of the controllable uniform coverage of the material and its easy availability without the need for expensive complex equipment. The anodizing process involves applying an electrical potential to tungsten while it is immersed in an electrolyte solution. This creates a thin layer of tungsten oxide on the surface of the metal. The thickness and properties of the resulting oxide layer can be controlled by adjusting the anodization conditions, such as the electrolyte solution, voltage, and the duration of the process. In this work, H3PO4 was used as the electrolyte to test whether these tungsten oxide layers would be useful for electron emitters, for use in electron guns and other devices that require high-quality electron emitters. The properties were evaluated using appropriate techniques. In general, anodization of tungsten to form thin layers of tungsten oxide layers is a promising technique for producing high quality electron emitters.
|
|
| |
|
|
SMV-2023-05: DI2023
Matějka, Milan ; Krátký, Stanislav ; Meluzín, Petr ; Košelová, Zuzana ; Chlumská, Jana ; Horáček, Miroslav ; Kolařík, Vladimír ; Knápek, Alexandr
Výzkum se soustředí na zkoumání a vývoj precizních kalibračních vzorků s reliéfními strukturami. Tyto vzorky jsou koncipovány pro kalibraci parametrů ve skenovacích elektronových mikroskopech (SEM). Testovací vzory umožňují ověření kvality zobrazovaní danou mikroskopickou technikou jako je celkové zvětšení, velikost zorného, rozlišení, deformace zobrazení v laterárních osách a další geometrická zkreslení. Pro přípravku jsou využívány precizní litografické techniky a další techniky vycházející z technologií zpracování křemíku z polovodičového průmyslu. Vývoj byl zaměřen na optimalizaci záznamu leptacích masek před přenosem obrazu do monokrystalické křemíkové podložky.
|
|
|
Diffusion Behavior of Analyte Molecules in a Nanoporous Matrix Created from Polystyrene Nanoparticles
Košelová, Zuzana
This study investigates the diffusion behavior ofanalyte molecules in a nanoporous matrix of polystyrene particles.Two approaches, steady-state current and potential stepchronoamperometry were employed to calculate diffusioncoefficients and compare the effect of nanoporous matrices withdifferent diameter of pores and different method ofimmobilization of enzyme. Pores were created with close packingof polystyrene nanoparticles. The covalent and cross-linkingimmobilization were used to immobilize the enzyme.Chronoamperometric measurement was applied to detect analyte.The study found that the presence of nanoporous matricesimmobilized on p-lysine affects diffusion. The potential stepchronoamperometry method showed the improvement ofdiffusion. This study provides insight into the diffusion behaviorof analyte molecules in nanoporous matrices, which can be usefulin optimizing the design of amperometric biosensors.
|
|
|
Ověřte možnost ošetření desek plošných spojů pomocí plazmy pro následnou povrchovou úpravu
Brokeš, Josef ; Košelová, Zuzana (oponent) ; Otáhal, Alexandr (vedoucí práce)
Tato práce se zabývá problematikou regenerace a čištění desek plošných spojů s důrazem na využití plazmové technologie. Byly zkoumány různé metody čištění povrchu, včetně manuálního čištění, průmyslové myčky a plazmového ošetření, a jejich vliv na následnou kvalitu lakování. V rámci práce je také prováděna systematická analýza vlivu plazmového ošetření na kvalitu laku a funkčnost desek, včetně zkoumání možnosti regenerace starších desek. Tato studie představuje základ pro další výzkum a rozvoj v této oblasti. Práce prezentuje také konstrukci a implementaci prototypu zařízení s plazmovým vyvíječem pro integraci do výrobní linky.
|
|
|
Nanoporous Enzyme-Based Impedimetric Biosensor
Košelová, Z.
The ordered nanopores surfaces has been studied in the field of biosensors for the detection of affinity interactions such as antigen-antibody or nucleic acid hybridization. Nanopores are frequently fabricated by anodic oxidation of aluminium. This method is practically simple method of highly ordered pore formation, but is not suitable for massive production. The principle of detection is usually based on the degree of pore blockage by biomolecular interaction that allows a sensitive electrochemical response. Here we show the development and characterization of the nanopore-based enzymatic biosensor for the detection of analytes. We performed and tested the concept of the simple and versatile method of nanopores formation on the electrode using non-conductive polystyrene nanoparticles. The variability in pore size was modulated by nanoparticles diameter (40 and 80 nm). We measured response of our designed biosensor using electrochemical impedance spectroscopy in presence of redox mediator at low potential. The smaller diameter of nanopores increases charge transfer resistance. Biosensors with 80 nm nanoparticles had behaviour similar to reference without nanoparticles, therefore the pore was too wide for this design. The limit of detection from Rct showed to be at most 0.01 mM for every sample type. This proposed biosensor contributes to the basic knowledge about nanopores sensors, and it could have a potential, for example, in the development of ―point of care‖ devices.
|
host ::
RSS.