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Effect of PWM control of a Laser Diode on Its Characteristics
Folta, Lukáš ; Ing. Jan Látal, Ph.D. (VŠB-TUO) (referee) ; Šťáva, Martin (advisor)
This bachelor's thesis deals with the measurement of the characteristics of two semiconductor laser diodes (LD) and its automation. The effect of current control method and LD temperature is compared here. The first chapter is devoted to the theoretical basis of the sub-areas of the experiments, a literature review dealing with laser control using pulse width modulation (PWM) is carried out, and the method of realization of the measured experiments is presented. The second chapter first defines the methods of recalculating the measured data and determines their uncertainties. The following are three subsections presenting the results of individual experiments. The first experiment deals with continuous control and the other two deal with pulse control, one using a commercially available laser driver and the other using a switch designed primarily for this work. The conclusion of the work contains a comparison of the measured results, evaluates their usability and suggests possible extensions of this work.
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Design of the telescope spectrograph for distant object analysis
Drobil, Tomáš ; Pořízka, Pavel (referee) ; Novotný, Jan (advisor)
Meteor spectra obtained from orbit include many spectral lines in the ultraviolet region, which is mostly absorbed by the atmosphere and thus cannot be observed from ground stations. This bachelor thesis focuses on the design of a spectrograph, placed in a 2U CubeSat, suitable for meteor observation and its spectral analysis in the range from the ultraviolet to near-infrared region. The design includes choice of a suitable camera. Based on the required parameters, several designs have been created, and the process is summarized in the last chapter. The research study of telescopes combined with spectrometers used for meteor observations is also included.
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Vibrational modes of nucleic acids components characterized by means of variable proton-deuterium exchange
Zoul, David ; Štěpánek, Josef (advisor) ; Šloufová, Ivana (referee)
Although the nucleon acid oscillatory spectra have been studied for a long period of time, many of oscillating modes have not been properly explained regarding their geometric sensitivity and weak binding. One of the possibilities how to acquire experimental data for interpretation of theese modes is to confront oscillating spectra of isotopes. The simplest is proton - deutron exchange. When molecules dissolve in heavy water they rapidly exchange the heteroatoms, but this is simultaneous for more stages, which leads to dynamic equilibrium state among various isotope forms. Statistic analysis of temporal progression of Raman spectra give us the possibility to analyze the spectra and to obtain unique experimental data. This technique is very promising for more complex nucleon acid segments to gain more structural information. This diploma thesis represents pilot study of introduced methodics. The objective is to implement adaptation of Raman spectrometr for given types of expiments and undertake first series of measurements. The results should clarify application bounds of proposed method refering to sensitivity, time constant of incident isotope exchange, severity of read-out in comparasion of achieved accuracy of the measurement.
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Design of compact spectrograph with shiftable spectral range based on transmission gratings
Malina, Jan ; Pořízka, Pavel (referee) ; Novotný, Jan (advisor)
The aim of this diploma thesis is to design a compact spectrometer with a transmission grating and a shiftable spectral range for the method of laser-induced breakdown spectroscopy (LIBS). The work in the theoretical part contains a basic description of spectroscopy and spectroscopic methods of LIBS, spectrometer and its individual parts. The practical part describes the spectrometer design procedure, introduces selected components and comments on the reason for their selection. Selected components are assembled into the final form of a spectrometer, which is further tested with the help of a simulation program to confirm its functionality. The result of the work is a comprehensive overview of the individual components of the spectrometer, aspects of its construction together with instructions and advice on its assembly, along with an example in the form of a designed set of commonly available catalog components.
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Impact of the atmosphere on laser ablation of matters
Černá, Svatava ; Hrdlička, Aleš (referee) ; Pořízka, Pavel (advisor)
This thesis deals with a general overview of laser-induced breakdown spectroscopy - ablation of material and plasma formation when a change of the surrounding environment occurs. The aim is to establish ideal conditions for improving detection, which is difficult for some elements when the measurement takes place in the ambient atmosphere. This is the reason why we change the ambient conditions, the gas (air, helium, argon) and its pressure. Buffer gases (helium, argon) influence the development of the material ablation and quality of generated plasma. That is why we inspect the changes in the signal according to particular atmospheres (signal change in buffer gases compared to the ambient atmosphere). The first part of the thesis presents the principle and physical nature of laser ablation with a brief search of experiments performed so far for similar purposes. Based on this search we determine conclusions about the influence of buffer gasses and pressure on the detection used gasses. In the second part of the work, the controlled experiment is presented, which consisted of the detection of spectral lines of fluorine and potassium, see chapter 5.6 and molecular transitions of calcium fluoride, see chapter 5.10. In a controlled experiment, we established two assumptions. The first assumption is the influence of the inert gas atmosphere, which should significantly improve the detection of fluorine and potassium compared to the air atmosphere. We confirmed this finding only for the argon atmosphere. In contrast, in the helium atmosphere, the detection of none of the elements improved. The second assumption is the effect of reducing the ambient pressure, which in combination with an inert gas should allow the detection of fluorine even at low concentrations in the sample. We consider the measured glass disk in chapter 5.7 to be such a sample. This assumption is not confirmed, as the increased intensity of the fluorine spectral line does not manifest itself in any way when the pressure in the vacuum chamber decreases. Finally, in chapter 7 from the results of individual parts of the experiment, the most suitable conditions for the future detection of the measured substances were proposed: fluorine, potassium and calcium fluoride molecules.
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Industrial Tester for Photometric Values of LED diodes Used in Automotive Signal Lighting
Gaži, Dominik ; Froehling, Kenneth (referee) ; Baumgartnerová, Alena (advisor)
V posledních letech zažili světlomety v autech obrovský technický rozvoj, který se podílel na jejich současné složitosti. Aby řidiči i zákazníci byli spokojeni, je využíváno různých technologií pro neustálé dosahování účinnějších a bezpečnějších světelných zdrojů. Společnosti usilují o minimalizaci ztrát ve výrobě ve snaze šetřit životní prostředí a konat ekonomicky. Tato práce se zabývá výzkumem osvětlovací techniky a návrhem jednoduchého a efektivního zařízení pro testovaní chyb LED plošných obvodů ve světlometech, to vše za účelem minimalizace strat. Dalším cílem je výzkum možností konstrukce takového zařízení z technologického hlediska.
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A new generation of electronic cigarettes
Kodad, Daniel ; Bělka, Miloslav (referee) ; Lízal, František (advisor)
The subject of the bachelor thesis Electronic cigarettes of the new generation is the research and comparison of two electronic cigarettes which use heated tobacco systems with regards to emitted particles. The subject of the experiments was the electronic cigarette I quit ordinary smoking (IQOS) and electronic cigarette GLO. For the purposes of this work an experimental track was designed in the Aerosol Research Laboratory at BUT FME where the emitted particles from electronic cigarettes mentioned above were measured using instruments Aerosol Particle Sizer 3321 and TSI SMPS 3936.
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Vibrational modes of nucleic acids components characterized by means of variable proton-deuterium exchange
Zoul, David ; Štěpánek, Josef (advisor) ; Šloufová, Ivana (referee)
Although the nucleon acid oscillatory spectra have been studied for a long period of time, many of oscillating modes have not been properly explained regarding their geometric sensitivity and weak binding. One of the possibilities how to acquire experimental data for interpretation of theese modes is to confront oscillating spectra of isotopes. The simplest is proton - deutron exchange. When molecules dissolve in heavy water they rapidly exchange the heteroatoms, but this is simultaneous for more stages, which leads to dynamic equilibrium state among various isotope forms. Statistic analysis of temporal progression of Raman spectra give us the possibility to analyze the spectra and to obtain unique experimental data. This technique is very promising for more complex nucleon acid segments to gain more structural information. This diploma thesis represents pilot study of introduced methodics. The objective is to implement adaptation of Raman spectrometr for given types of expiments and undertake first series of measurements. The results should clarify application bounds of proposed method refering to sensitivity, time constant of incident isotope exchange, severity of read-out in comparasion of achieved accuracy of the measurement.
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Planar, linear and fold structures of Blanik orthogneiss
MORAVCOVÁ, Kateřina
This MSc. thesis deals with a research of Blanik orthogneiss and its planar and linear structural elements. The work is divided into a theoretical and practical part. The theoretical part provides an overview deformation processes in geological bodies and resulting structures. The practical part provides a structural analysis of 34 outcrops in the area of interest. Outcrops are described in terms of petrological characteristic and its geological structures, which were measured. Final data were transformed into diagrams. One sample of the blanik orthogneiss was also subjected to microstructural analysis. Twelve samples were analyzed by a portable spectrometer Delta Professional.
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