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An enhanced theoretical approach for accurate measurements of the optical and energy characteristics of semiconducting materials
Allaham, Mohammad M. ; Košelová, Zuzana ; Sobola, Dinara ; Fohlerová, Zdenka ; Knápek, Alexandr
The absorption coefficient is an important optical property in characterizing semiconducting materials. It plays a significant role in studying optical characteristics, electrical structure, energy band structure, and the creation/annihilation of excitons when a semiconducting material absorbs electromagnetic radiation. In this study, an enhanced theoretical model will be introduced and applied to characterize thin films prepared from UPR4 (unsaturated polyester resin) single-component epoxy resin, which is important to study the charge flow at the interface of tungsten-UPR4 composite field emission cathodes.
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Application of spectrophotometers
Klimešová, Marie ; Čmiel, Vratislav (referee) ; Kolář, Radim (advisor)
The work deals with the important analytical method - spectrometry. It is based on measurement of absorption of radiation in a wavelength range. On this principle can determine the absorbance and transmittance of the measured samples. The thesis also describes events related to the excitation of molecules. These include absorption, vibrational relaxation, internal conversion, inter-system crossing, fluorescence, phosphorescence and delayed fluorescence. The practical part includes three experimental measurements. The first measurement is the concentrations of potassium permanganate solution. In a second experiment, verifying the validity of Lambert-Beer law. In the third experiment, the fluorescence measurement of fluorescein and detection of fluorophore concentration dependence on fluorescence intensity. Measurement is performed in an environment SpectraSuite with the use of school spectrometers USB2000 + and USB650 Red Tide.
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Spectrophotometry of ROS species with focus on hydrogen peroxide
Zhorný, Lukáš ; Hořavová, Lenka (referee) ; Provazník, Ivo (advisor)
The main theme of this work is spectrophotometry. The first chapter describes the theoretical problems of the topic, relevant units and formulas for calculating the absorbance of the solutions of given concentrations. Further disclosed herein is a spectrophotometer, its individual parts, and the principle on which the unit is based. The last chapter of the theoretical introduction to this work is focused on the production of ROS in living organisms and especially in plants, and then there are some spectrophotometric methods for determining the concentration of ROS. The practical part describes the method using TiCl4 and method using KI. Both methods were used to determine the hydrogen peroxide concentration and subsequent measurement of absorbance of solutions of standard hydrogen peroxide added interfering substances. Then, the statistical analysis of the measured data and the assessment of the impact of these interferents to measure absorbance. The first of these methods proved to be suitable for a given measurement.
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Spectrophotometry of ROS species with focus on hydrogen peroxide
Zhorný, Lukáš ; Hořavová, Lenka (referee) ; Provazník, Ivo (advisor)
The main theme of this work is spectrophotometry. The first chapter describes the theoretical problems of the topic, relevant units and formulas for calculating the absorbance of the solutions of given concentrations. Further disclosed herein is a spectrophotometer, its individual parts, and the principle on which the unit is based. The last chapter of the theoretical introduction to this work is focused on the production of ROS in living organisms and especially in plants, and then there are some spectrophotometric methods for determining the concentration of ROS. The practical part describes the method using TiCl4 and method using KI. Both methods were used to determine the hydrogen peroxide concentration and subsequent measurement of absorbance of solutions of standard hydrogen peroxide added interfering substances. Then, the statistical analysis of the measured data and the assessment of the impact of these interferents to measure absorbance. The first of these methods proved to be suitable for a given measurement.
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Application of spectrophotometers
Klimešová, Marie ; Čmiel, Vratislav (referee) ; Kolář, Radim (advisor)
The work deals with the important analytical method - spectrometry. It is based on measurement of absorption of radiation in a wavelength range. On this principle can determine the absorbance and transmittance of the measured samples. The thesis also describes events related to the excitation of molecules. These include absorption, vibrational relaxation, internal conversion, inter-system crossing, fluorescence, phosphorescence and delayed fluorescence. The practical part includes three experimental measurements. The first measurement is the concentrations of potassium permanganate solution. In a second experiment, verifying the validity of Lambert-Beer law. In the third experiment, the fluorescence measurement of fluorescein and detection of fluorophore concentration dependence on fluorescence intensity. Measurement is performed in an environment SpectraSuite with the use of school spectrometers USB2000 + and USB650 Red Tide.
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Optical properties of historical paint pigments under near infrared (NIR) radiation
Blažek, Jan ; Zitová, Barbara ; Tichý, T. ; Vašutová, V.
The knowledge of paint pigments' optical characteristics enables the selection of an appropriate imaging methodology for non-invasice artwork investigation. i. e. optimising the visibility of preparatory layers using conventional photographic cameras modified for data acquisition in the near infrared wavelength range. This contribution deals with the limits of this simple method in the analysis of selected common pigments used in prepared canvas mock-ups with typical structure including ground layer and underdrawings of various compositions.
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Device for Measurement of Optical Visibility
Rejfek, L. ; Brázda, V. ; Fišer, Ondřej
This paper is about a proposed device for the optical visibility measurement. This device is usable for monitoring of the fog mightiness. The principle of device is based on comparison of attenuation on two optical links. The fog mightiness is determined by the using of the Beer-Lambert Law. The philosophy of electrical arrangement is also explained.
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