National Repository of Grey Literature 3 records found  Search took 0.00 seconds. 
Design of a sample holder with electrical contacts for UHV SEM/SPM
Krutil, Vojtěch ; Vlček, Ivan (referee) ; Urban, Pavel (advisor)
The presented thesis focuses on designing a sample holder for an UHV SEM/SPM microscope suitable for using in low temperature (20 K - 300 K) applications. This newly designed sample holder is equipped with ten spring-loaded contacts for electrical connection of a transport pallet to the sample holder, which will be equipped with a temperature sensor and a heating element. Two quadruples of contacts are reserved for the sample and the temperature sensor and the remaining pair for the heating element. A thorough research study of commercially available sample holders indicates that the holders for the intended use are not available on the market. In the low-temperature tests of the newly designed sample holder, the limit temperature of the 24 K was reached in a test vacuum chamber with a flow cooling system. The ambient temperature was 300 K. The contact function was successfully verified by measuring the transient electrical resistance at the fixed and the spring contact sections. Additionally, a modification of the sample holder for high temperature (300 K - 700 K) was suggested.
The mathematical theory of juggling
Zamboj, Michal ; Slavík, Antonín (advisor) ; Halas, Zdeněk (referee)
Title: The mathematical theory of juggling Author: Bc. Michal Zamboj Department: Department of Mathematics Education Supervisor: RNDr. Antonín Slavík, Ph.D. Abstract: This diploma thesis extends the bachelor thesis of the same name. It deals with the graphic representation of juggling sequences by the cyclic diagram. Using the Burnside theorem and cyclic diagrams, we calculate the number of all genera- tors of juggling sequences. The relation between juggling and the theory of braids is described as well. The mathematical model of inside and outside throws is made from an empirical observation of trajectories of balls. Braids of juggling sequences and their attributes are provided using a real model of ladder. A sketch of the proof of the theorem that any braid is juggleable is given as well.
Design and verification of low temperature parts of UHV SEM/SPM stage
Pola, Tomáš ; Vlček, Ivan (referee) ; Urban, Pavel (advisor)
This thesis focuses on experimental verification and experimental-based improvements of designed low temperature parts of stage of the UHV SEM/SPM microscope, which operates in temperature range from 20 K to 700 K. The main focus is on the functionality verification of thermal insulation pad (InBallPad) as well as on the effect of length and contact quality of braid on minimal achievable temperature. The contact quality of sample holder with sample carrier realized with two springs is investigated together with influence of thermal contact resistances on achievable temperature. The thesis also contains a calculation model used for cooldown times and minimal temperature estimation. In the conclusion of this work several future experiments are suggested which could explain some of the observed, yet unexpected, phenomena.

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