PubMed İndeksli Yayınlar Koleksiyonu / PubMed Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7645
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Article Citation - WoS: 8Citation - Scopus: 8Design and Performance Comparison of Polymer-Derived Ceramic Ambigels and Aerogels(American Chemical Society, 2023) Soraru, Gian Domenico; İçin, Öykü; Semerci, Tuğçe; Ahmetoğlu, Çekdar VakıfThis work reports the synthesis and characterization of preceramic-and polymer-derived SiOC aerogels obtained from a commercial siloxane resin. The preceramic aerogels were obtained by ambient pressure drying (ambigels) and CO2 supercritical drying. Despite different drying processes, the final ceramic ambi/aerogels have very similar microstructural features in density, porosity, pore size, and specific surface area. Both materials have shown promising results for oil sorption and water cleaning. Supercritically dried-SiOC aerogel had low thermal conductivity with 0.046 W.m(-1).K-1 at RT and 0.073 W.m(-1).K-1 at 500 degrees C. These results suggest that substituting the rather complicated and expensive CO2-SC drying with the more friendly and cheap ambient pressure drying can be done without having to accept significant microstructural/property degradation.Article Citation - WoS: 660Citation - Scopus: 692Emission of Coherent Thz Radiation From Superconductors(American Association for the Advancement of Science, 2007) Özyüzer, Lütfi; Koshelev, A. E.; Kurter, Cihan; Gopalsami, N.; Li, Q.; Tachiki, M.; Kadowaki, K.; Yamamoto, T.; Minami, H.; Yamaguchi, H.; Tachiki, T.; Gray, Kenneth E.; Kwok, W. K.; Welp, U.Compact solid-state sources of terahertz (THz) radiation are being sought for sensing, imaging, and spectroscopy applications across the physical and biological sciences. We demonstrate that coherent continuous-wave THz radiation of sizable power can be extracted from intrinsic Josephson junctions in the layered high-temperature superconductor Bi2Sr2CaCu 2O8. In analogy to a laser cavity, the excitation of an electromagnetic cavity resonance inside the sample generates a macroscopic coherent state in which a large number of junctions are synchronized to oscillate in phase. The emission power is found to increase as the square of the number of junctions reaching values of 0.5 microwatt at frequencies up to 0.85 THz, and persists up to ∼50 kelvin. These results should stimulate the development of superconducting compact sources of THz radiation.