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Piezoelectric nanofiber materials for wearable electronics
Frolíková, Štěpánka ; Škarvada, Pavel (referee) ; Macků, Robert (advisor)
This thesis deals with the influence of production parameters on the morphology of PVDF nanofibers produced by electrospinning. Nanofibers are generally a widely used material, nanofibers are generally a widely used material, they can also have piezoelectric properties, which gives them a specific spectrum of use, eg in biosensors. The production of nanofibers was realized by electrospinning. A scanning electron microscope was used to examine the morphology and surface properties. The aim of this thesis is to compare the properties of PVDF nanofibers produced under different settings of production parameters.
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Controlled light source
Pazderský, Tomáš ; Macků, Robert (referee) ; Škarvada, Pavel (advisor)
The aim of the Master´s thesis is proposing and implementation of computer controlled optical radiation source. The theoretical part describes the photometric, the radiometric quantities, applied components such as LED, the microcontroller and possible methods for the LED brightness control. The development of the device is described from the selection of the individual LEDs to the end of the device assembling and programing. On the several LEDs were made properties measurement. A circuit with microcontroller was designed and then was fabricated. The device was programmed for communication and control from the PC. The entire electronic is fitted in the metal frame of the construction box and finally the device functionality is tested.
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Raman spectroscopy teaching equipment
Indra, Zdeněk ; Sedlák, Petr (referee) ; Škarvada, Pavel (advisor)
This thesis examines the principle of the Raman phenomenon and the function of the Raman spectrometer in order to build a low-cost Raman spectrometer assembly for school laboratory teaching. The thesis lists the important parts of the device and describes their key features. Subsequently, the selection of each component is discussed and a basic experiment is performed to verify the principle of this spectrometer. In the final part, a low-cost Raman spectrometer is constructed and tested thanks to the knowledge gained.
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Solar cell non-destructive analysis
Černý, Michal ; Škarvada, Pavel (referee) ; Macků, Robert (advisor)
This thesis briefly analyse contemporary situation of photovoltaic systems and their actual developemenet. It shows a typical properties of most produced up-to-date types. Decision point of this thesis consist in nondestructive analyse of monocristalic unijunction solar cells. It describes two main diagnostic aproaches. First – through the use of measuring of VA characteristics, second – through the use of measuring noise characteristics. With selected samples are performed experimental measurements and estabilished basic parameters. In case of drone analysis considerably attention is devoted to experimental equipment for automatized measuring of spectral power density. This experimental equipment is consequently used for measuring some samples where we can observe microplazmatic noise.
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Local optical and electrical characteristics of optoelectronic devices
Škarvada, Pavel ; Hrabovský, Miroslav (referee) ; Lazar, Josef (referee) ; Tománek, Pavel (advisor)
Solar energy conversion, miniaturization of semiconductor devices and associated lifetime, reliability and efficiency of devices are the basic premise of this work. This work is focused on the study of optoelectronic devices especially solar cells and its nondestructive diagnostic. Solar cells are advantageous for study mainly because the pn junction is located near the surface and contains a lot of inhomogeneities. It has been difficult until recently to investigate their local physical (electrical and optical) parameters due to the size of inhomogeneities. Behavior of inhomogeneities can be well understood with knowledge of its local properties. Establishment of measurement workplace, that satisfies requirements for measurement of local emission and optically induced current measurement, allows us detection and localization of inhomogeneities with spatial resolution more or less 100 nm. The core of thesis is characterization of imperfection using nondestructive techniques in the macroscopic region but primarily in microscopic region using scanning probe microscopy. Integral parts of the work are characterization techniques for photoelectrical devices, microscopic techniques and data processing. Scanning near-field optical microscope is used for the purpose of microscopic characterization such as topography, local optical, photoelectrical and electrooptical properties of structures in high spatial resolution. Locally induced current technique, current voltage characteristics, emission from reversed bias pn junction measurement including its thermal dependence are used for samples investigation in macroscopical region. It is possible to localize defects and structure inhomogeneity using mentioned techniques. Localised defects are consequently analyzed for composition and measured using electron microscopy. Specific outputs of work are classification of photoelectric devices defects and specification of nondestructive characterization techniques used for defect detection. Experimental characterization techniques are described together with defects measurement procedures. The key output is the catalog of serious defects which was detected. Particular defects of samples are shown including describe of its properties and physical meaning.
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Light diffraction and interference in laboratory exercises
Dvořák, Tomáš ; Šicner, Jiří (referee) ; Škarvada, Pavel (advisor)
The main purpose of this semestral project is suggestion and construction the laboratory task for measuring interference and diffraction of light, which would be teached in laboratory of physics. According to gained informations about optical phenomenon, the physical construction of the laboratory task was made. Subsequently the CMOS camera was connected and installed. There was also developed a software for controlling this camera. Software is able to control all supported functions of camera, capture and save samples from live recording and show the intensity decomposition of captured images. The most important function of developed software is ability to measure distances between particular diffraction local extremes.
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Pipetting indicator
Demjan, Michal ; Čmiel, Vratislav (referee) ; Škarvada, Pavel (advisor)
Thesis “LED pipetting indicator” considers possibilities of indication of working process using microplates with 96 and 48 wells. It is also considering low financial costs of the final product, same as universality for using microplates intended for different uses and researches and also for using microplates made by different manufacturers. This work follows designing of hardware, software and casing. Device is using 96 LED diodes, controlled by microcontroller which is able to communicate with system of higher level.
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Vehicle testing station
Škarvada, Pavel ; Kučera, Pavel (referee) ; Hradil, Dušan (advisor)
The thesis of the project is testing station for cars and light utility vehicles with auto service. It is designed for building plot located in Brno, district Komín. The building is designed as a without basement, single-storey with flat roof. The project suggests paved roads and parking spaces for visitors and employees. The building is not designed as a low energetic.
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Analysis of solar cell surface features
Lipr, Tomáš ; Macků, Robert (referee) ; Škarvada, Pavel (advisor)
This thesis is focused on the study of electrical and optical properties of solar cell samples using the near field optical microscope. Process of the image formation is described. Artefacts which are presented on some of topography images are described, too. There are some timing problems with measuring of the sample local electric response. If the measuring and scanning devices are not in the time synchronization there will be some difficulties with measured data representation and 2D image offline formation. Created electronic for SNOM and measuring devices synchronization is presented.
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Remote fault monitoring system
Jarůšek, Jakub ; Trčka, Tomáš (referee) ; Škarvada, Pavel (advisor)
In practice, optical non-contact measurement of distance and displacement is divided into various methods that use a different parameter of the optical (light) signal. Some methods are explained in the work. The triangulation method is described in more detail. This method is used to measure and monitor the displacement of geological faults. For this monitoring, a low-budget device is designed, which uses lasers and a sensor to determine the displacement of the measured object in a certain time interval. The whole system will serve as verification of data measured by magnetoresistive sensors.
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