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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Přesnost a dynamika lineárních piezo motorů / Precision and dynamics of linear piezo motors

Ilichman, Ondřej January 2014 (has links)
The work deals with the design, control, precision and dynamics of linear piezoelectric motors from PiezoMotor Uppsala AB. The aim of this thesis is to evaluate the applicability of the loaned engine in a mass spectrometer. In introduction‘s section of this work is discussing the design principles of functionality, materials used, procedure and types of piezoelectric motors. It focuses the choice of hardware and design of mechanical assemblies, which could replace the current mechanism with electromagnetic motors. Then we designed and fabricated a test report with hired piezoelectric motor. In NI LabView development environment is created test application for control and measurement. The final section is devoted to a summary of the positive and negative features of the hired piezoelectric motor and evaluation of accuracy and dynamics.
12

CMOS kompatibilní piezoelektrický rezonátor s FET strukturou pro řízení vlastností grafenové monovrstvy / CMOS compatible piezoelectric resonator with FET structure for graphene monolayer properties modulation

Gablech, Imrich January 2018 (has links)
Práce je zaměřena na výzkum nové struktury umožňující charakterizaci fyzikálních vlastností grafenu při přesně řízených podmínkách. Návrh spojuje MEMS piezoelektrický rezonátor spolu s Hall Bar/FET strukturou. Tento přístup umožňuje měnit vlastnosti grafenu odděleně nebo společně dvěma metodami. Mechanický způsob je založen na relativní deformaci způsobené rezonátorem, na kterém je umístěna grafenová monovrstva. Navrhovaná struktura umožňuje měřit vlastnosti grafenu vyvolané pouze změnou mechanického pnutí a frekvencí nucených kmitů bez vlivu vnějšího elektrického pole. Druhý přístup přidává možnost ovládat fyzikální vlastnosti grafenu pomocí elektrického pole FET struktury. Tato technika využívá grafenovou monovrstvu jako laditelný sensor pro molekulární detekci. Měření koncentrace v jednotkách ppb není konstrukčně ničím limitováno. Realizované frekvenčně laditelné piezoelektrické MEMS rezonátory s monovrstvou grafenu budou využitelné v mnoha oblastech pro detekci na molekulové úrovni. Výsledné struktury budou vyrobeny v souladu s požadavky na bio- a CMOS kompatibilitu.
13

Vývoj nanovláknového PVDF senzoru / Development of PVDF nanofibers sensor

Klásek, Matyáš January 2020 (has links)
This diploma thesis deals with the feasibility of using PVDF nanofibers as an active sensor layer generating electrical signal. PVDF and related electromechanical effects are described. A research study is conducted regarding existing PVDF nanofiber applications and based on it, an event sensor design utilizing triboelectric effect and electrostatic induction is proposed. The electrical response of the layers is experimentally investigated and a pulse detection algorithm is conceived and implemented. Finally, a way of integrating the sensor into a rail track is proposed.
14

Detekce nápravy v systému vážení za jízdy / Axle detection in the weighing vehicle system

Mičulka, Martin January 2021 (has links)
This master's thesis deals with the Weight in Motion systems (WIM). The main goal is to create simulation software that detects dual tires assembly with respect to the angle with which the sensor is embedded into the road. Thesis also contains literature search of available solutions of weighing systems and the sensors which are used in these systems. Subsequently, the thesis contains software for recognizing simple assembly or dual tires assembly from real measured data. Software solutions were developed using programming language Python v3.7. All source codes were developed in PyCharm Community Edition 2020.
15

Dynamické vážení vozidel / Weight-In-Motion

Kašpárek, Ladislav January 2009 (has links)
This Master's Thesis deals with Weight-In-Motion (WIM) Systems. It focuses on piezopolymer-coaxial-cable-based sensors. The work contains summary of WIM sensors, methods for signal processing and evaluation provided by WIM sensors. The design of WIM station including measuring chain is also drawn out here. Basic meaurements on sample output from the sensor are carried out using formely designed amplifier. By this, its properties and suitability can be assessed.
16

Zařízení pro ovládání mikroposuvu / Microposition control device

Kokeš, Ondřej January 2010 (has links)
Presented thesis analyses a function of the particular type of the nanopositioner with aim to suggest and construct an electronic device suitable for control of the nanopositioner slider. In presented material there is a description of the control signals and possibility of their generating in the respect of slider movement accuracy. The main goal of the thesis is to describe electronic units ranging from power supply, control processor unit part to end part that directly joint nanopositioner. There is also programme equipment for microcontroller and computer, communication description, movement measuring and calibration and draft for the close-up of the control loop for additional increase of the movement accuracy.
17

Měření náhradního obvodu piezoelektrického rezonátoru / Measurment of Equivalent Circuit of Piezoelectric Resonator

Vomočil, Vojtěch January 2010 (has links)
This theis deals with the general overview of the piezoelectric theory, focused both on the mathematical description and on the attributes of piezoelectric materials. It further focuses on the description of piezoelectric resonators with a more detailed explantation of their equivalent scheme and measurement methods of its single elements. The practical part of the thesis rests on the proposal of a measurement apparatus which will serve to measuring the equivalent circuit piezoelectric resonator elements. The realization of the apparatus and its functionality testing are described. In the experimental part of the thesis, the measured rates are processed and levels of the electric equivalent circuit elements of the used piesoelectric resonator for the basic and the two higher closest resonance frequency are set. The measured results are compiled into a standard measurement protocol. This thesis should place basics to the growing laboratory. It should also be a source of necessary theoretical and practical information for this lab.
18

Chování feroelektrik v teplotní oblasti / The behaviour of ferroelectrics in the temperature range

Czanadi, Jindřich January 2012 (has links)
The submitted thesis describes characteristics and use of the ferroelectric material which has their utilization in electronics and electro technical industry. The thesis describes behaviour ferroelectrics in temperature range. A suitable workplace was designed and its functionality was verified in selected ferroelectrics samples dependence of temperature of components of complex permittivity.
19

Modelování a verifikace piezoelektrického generátoru / Modelling and Verification of Piezoelectric Generator

Lán, Radek January 2015 (has links)
This master's thesis deals with the development and verification of the model of the piezoelectric generator, incl. determination of its parameters. This mathematical model should be used as a tool for development of new devices, especially for analysis of applicability of available energy source (vibration) and for design of device itself. At first the review of energy harvesting is described deeply. Subsequently piezoelectric generators and the ways how we can model them, are depicted in details. The methodology of parameters estimation and model development is presented in state space or in MATLAB/Simulink environment and applied on the commercial generator Midé V21BL. A device has been made within the scope of the thesis, which can be used as an universal tool in experiments with generator. Finally the model is applied on the analysis of energy yield from man's walk and there is also brief introduction to model modifications.
20

Návrh vibračního generátoru s využitím nelineárních charakteristik / Design of Vibration Energy Harvester with Using of Non-linear Characteristics

Rubeš, Ondřej January 2016 (has links)
This thesis is focused on design of piezoelectric energy harvester with additional nonlinear stiffness. Linear generator has very narrow resonance frequency bandwidth. It makes the resonance mechanism very sensitive to tuning up of the resonance frequency and it can be tuned only for one narrow vibration peak. The main idea for using of the vibration energy harvester with nonlinear stiffness is to make resonance frequency bandwidth wider, so the generator will be useable for more excitation frequencies. In this thesis is used generator Midé V21BL and additional nonlinear stiffness is realized with permanent magnets.

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