National Repository of Grey Literature 19 records found  1 - 10next  jump to record: Search took 0.01 seconds. 
Wearable Circularly Polarized Rectangular Ring-Slot Antenna With Chamfered Corners
Vašina, Petr
This paper deals with a circularly polarized rectangular ring-slot antenna with chamfered corners designed for 5.8 GHz ISM frequency band for off-body communications. The antenna, originally designed for conventional microwave substrate, has been redesigned for a soft-shell textile material to create its wearable version. For its manufacturing, the screen printing technology has been exploited. Experimental results prove that the wearable version of the antenna located on a muscle equivalent phantom achieves the impedance bandwidth more than 6.3 % for the reflection coefficient less than -10 dB, the axial ratio (AR) bandwidth 1.7 % for the AR less than 3 dB and the RHCP gain more than 6.0 dBi.
Human activity detection in indoor spaces via WLAN network
Sekanina, Tomáš ; Vašina, Petr (referee) ; Miloš, Jiří (advisor)
Bachelor thesis represents possibilities of use WLAN network and standard IEEE 802.11n for object or human detection in a room with different scenarios. Bachelor thesis includes a theoretical description of WLAN network and family of WLAN standards IEEE 802.11 with detailed focus on standard IEEE 802.11n and its physical layer. Attention is also paid to the wave propagation inside buildings. It also includes description of measuring Wi-Fi INTEL 5300 NIC, CSI Tool 802.11n and controlling measuring NIC in operating system Linux. In practical part is demonstrated analysis of high-throughput packets using standard 802.11n. Results of measurement of object and human detection in a room are exported to programming language MATLAB and there are analyzed. Results of experiments are discussed in conclusion of bachelor thesis.
Optimization of User Interface of an Information System
Vašina, Pavel ; Hynek, Jiří (referee) ; Bartík, Vladimír (advisor)
The goal of this project is analysis of the original user interface of internal information system iAdmin belonging to Payment institution Roger a.s. company, finding and definition of its problems and implementation of its improvements with the use of web technologies (HTML, CSS, JavaScript) and Python language, so it will be user friendly, more effective in production, and easily extensible in future.
Textile SIW Rectangular Ring-slot Antennas for Off-body Communication
Vašina, Petr
In this paper, a textile SIW rectangular ring-slot antenna for the ISM frequency band 5.8 GHz is proposed. The antenna radiates a linearly polarized wave with the maximum radiation in the perpendicular direction to the antenna plane. The antenna is fabricated on the soft-shell fabric in the two versions. In the first version, the conductive layers were fabricated by a self-adhesive copper foil. In the second version, the conductive layers were fabricated by the screen printing on a foil ironed on the soft-shell fabric. Experimental results prove that the proposed antenna fabricated by copper foil achieves the impedance bandwidth of 3.1 % for the reflection coefficient less than -10 dB and the gain of 6.91 dBi. While screen printing antenna achieves the impedance bandwidth of 2.93 % for the reflection coefficient less than -10 dB and the gain of 7 dBi, respectively.
W-B-C Nanostructured Layers - Microstructure and Mechanical Properties
Buršík, Jiří ; Kuběna, Ivo ; Buršíková, V. ; Souček, P. ; Zábranský, L. ; Mirzaei, S. ; Vašina, P.
Several W-B-C layers were prepared by magnetron sputtering. The microstructure of thin layers was observed by means of scanning and transmission electron microscopy on cross sections prepared using a focused ion beam. Both undisturbed layers and the volume under indentation prints were inspected.
Characterization of Ta-B-C nanostructured hard coatings
Buršík, Jiří ; Buršíková, V. ; Souček, P. ; Zábranský, L. ; Vašina, P.
Microstructure and mechanical properties of Ta-B-C nanocrystalline layers prepared by magnetron sputtering were studied. DC magnetron sputtering was used to prepare thin layers on rotated substrates. Various deposition parameters were tested. Microstructure of layers was studied by means of scanning and transmission electron microscopy on thin lamellar cross sections prepared using a focussed ion beam. Both undisturbed layers and the volume under relatively large indentation prints (load of 1 N) were observed. The microstructure observations were correlated with mechanical properties characterized by means of nanoindentation experiments in both the static and the dynamic loading regime. Elastic modulus, indentation hardness and fracture resistance of prepared nanostructured coatings were evaluated and discussed.
Impact resistence on nanocomposite Mo-B-C- and W-B-C coatings deposited using magnetron sputtering technique
Fořt, Tomáš ; Grossman, Jan ; Daniel, Josef ; Sobota, Jaroslav ; Dupák, Libor ; Buršíková, V. ; Zábranský, L. ; Souček, L. ; Mirzaei, S. ; Alishahi, M. ; Vašina, P. ; Buršík, Jiří
Recently, based on attractive mechanical properties of boride and carbide based X2BC ternary compounds (X = Mo, W and Ta) they became subjects of both theoretical calculations and experimental work. In the case of stoichiometric composition, X2BC with X = Mo, W and Ta are very promising candidates for protection of cutting and forming tools due to their unusually stiffness and moderate ductility.\nIn this work we focus on nanostructured Mo-B-C and W-B-C layers grown by magnetron sputtering on high speed steel (HSS) substrates. Mechanical properties of the layers were characterized by nanoindentation experiments in both static and dynamic loading regimes. Elastic modulus, indentation hardness and fracture resistance were evaluated and discussed. The fracture resistance of both Mo-B-C and W-B-C coatings was compared using both indentation and dynamic impact tests.\n
Characterization of Mo-B-C nanostructured coating microstructure by means of AEM and GDOES
Buršík, Jiří ; Svoboda, Milan ; Švábenská, Eva ; Buršíková, V. ; Souček, P. ; Zábranský, L. ; Vašina, P.
A Mo-B-C nanostructured coating was prepared on WC-Co hard-metal substrate by magnetron sputtering. The details of microstructure of deposited thin layer as well as elements redistribution caused by subsequent annealing at 1000°C were studied by several experimental techniquec.
Textile Microwave Components
Hotovec, Jakub ; Láčík, Jaroslav (referee) ; Vašina, Petr (advisor)
This bachelor thesis is focused on possibilities of designing components integrated on substrate, where substrate is fabric. It contains theoretical information about the SIW structure, measurement of dieletric parameters of three fabrics, design, synthesis and production of waveguide, a three port divider and a band-pass filter on three substrates. For simulation CST Microwave Studio is used
Deposition of Hard Yet Moderately Ductile MoBC Coatings by p-DC Magnetron Sputtering
Souček, P. ; Buršíková, V. ; Zábranský, L. ; Buršík, Jiří ; Vašina, P.
Novel nanolaminated MoBC coatings were prepared using a combination of non-reactive direct current and pulsed direct current magnetron sputtering. Depending on the deposition conditions the coatings were either of amorphous or of nanocomposite nature. Nanocomposite coatings showed good hardness and Young’s modulus and showed no tendency to form cracks even for high-load nanoindentation testing.

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