894 research outputs found
Die gesellschaftliche Verteilung von Traurigkeit. Eine emotionssoziologische Analyse
Zusammenfassung: Die Soziologie interessiert sich für die soziale Verteilung und Determinanten von Traurigkeit als Teil der Gefühlskultur einer Gesellschaft. Sie eröffnet zugleich Potenziale für das Themenfeld der sozialen Ungleichheit von Emotionen. Auf der Grundlage einer Querschnittsanalyse von Daten des Schweizer Haushalt-Panels (SHP) werden Zusammenhänge zwischen der Häufigkeit der erlebten Traurigkeit und Merkmalen der sozialstrukturellen Position, des sozialen Kontextes sowie in Abhängigkeit von kritischen Lebensereignissen geprüft. Der Beitrag bestätigt Variationen von Traurigkeit entlang sozialer Merkmale wie Geschlecht, Einkommen, Alter, Nationalität und Sprachregio
Effect-specific analysis of propagation parameters
Results of propagation measurements with the satellite OLYMPUS carried out at 12.5, 20, and 30 GHz at the Research Center of the Deutsche Bundespost Telekom are discussed. In particular, attenuation, scintillation, and depolarization measurements are analyzed with special emphasis on frequency scaling of the various effects
Season Tickets on Sale for 1988-89 UD Art Series
News release announces that tickets are now on sale for the 1988-89 University of Dayton Arts Series
Electrically tuned microwave devices using liquid crystal technology
An overview of liquid crystal technology for microwave and millimeter-wave frequencies is presented. The potential of liquid crystals as reconfigurable materials arises from their ability for continuous tuning with low power consumption, transparency, and possible integration with printed and flexible circuit technologies. This paper describes physical theory and fundamental electrical properties arising from the anisotropy of liquid crystals and overviews selected realized liquid crystal devices, throughout four main categories: resonators and filters, phase shifters and delay lines, antennas, and, finally, frequency-selective surfaces and metamaterials.Pouria Yaghmaee, Onur Hamza Karabey, Bevan Bates, Christophe Fumeaux and Rolf Jakob
Network-Structured BST/MBO Composites Made from Core-Shell-Structured Granulates
A finite element method (FEM)-based simulation approach to predict the tunability in composite materials was developed and tested with analytical data. These tests showed good prediction capabilities of the simulation for the test data. The simulation model was then used to predict the tunability of a network-structured composite, where the dielectric phase formed clusters in a paraelectric network. This was achieved by simulating a reciprocal core-shell unit cell of said network. The simulation showed a high tunability for this network model, exceeding the tunability of the analytically evaluated layered, columnar, and particulate model. The simulation results were experimentally verified with a Ba0.6Sr0.4TiO3/Mg3B2O6 (BST/MBO) composite, where core-shell granulates were made with a two-step granulation process. These structured samples showed higher tunability and dielectric loss than the unstructured samples made for comparison. Overall, the structured samples showed higher tunability to loss ratios, indicating their potential for use in tunable radio frequency applications, since they may combine high performance with little energy loss
The effect of ZnO-B₂O₃ addition on the dielectric properties and microstructure of screen-printed low-sintered BST thick films
Preparation of integrated passive microwave devices through inkjet printing
Barium strontium titanate (BST) is a promising material for passive tunable microwave devices such as phase shifters or tunable matching networks. This publication covers the preparation of BST thick-films for microwave applications through inkjet printing. Two barium strontium titanate (BST) inks were prepared, printed on alumina substrates and sintered at different temperatures. The first ink was prepared with pure BST and sintered between 1100°C and 1200°C. The second ink was prepared with a BST–ZnO–B2O3 composition and was suitable to reduce the sintering temperature down to 800°C. The microstructure of the thick-films reveals the evolution of grain growth with increasing sintering temperature in the thick-films. Furthermore, a reaction with the substrate was observed for both inks at high sintering temperatures. The microwave characterization of the thick-films shows that for the permittivity and the tunability of the films, the effect of grain growth and reaction with the substrate compete against each other. Hence, the optimal microwave properties were achieved at a transition temperature, where first additional phases could already be observed. Even though, the properties are poorer for lower sintering temperatures, the investigations show that the preparation of silver- or gold-based metal–insulator–metal (MIM) structures through inkjet printing is possible with this composition. This allows various new design concepts for partly or fully inkjet printed passive microwave devices. Furthermore, it gives the opportunity for a future integration of passive tunable microwave devices in a low temperature co-fired ceramic (LTCC) fabrication process.</jats:p
Microstructure and microwave properties of low temperature sintered BST (Ba₀̣₆Sr₀̣₄TiO₃) thick-films abd their applicability to co-firing processes
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