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[en] Following their proof-of-concept paper published in 2003, in the span of ten years Microwave Kinetic Inductance Detectors (MKIDs) found both widespread scientific interest in the superconducting electronics community and in technological applications as particle detectors. We explore the possibility of using Granular Aluminum (GrAl) with the goal of decreasing the Noise Equivalent Power (NEP) of the resulting MKIDS. One of the most attractive features of GrAl films is the wide-range tunability of the sheet resistance, which is in turn directly linked to the kinetic inductance. To exploit this resource we propose a theoretical model for the dependence of the NEP with the kinetic inductance fraction of the detector. We quantify the interplay between kinetic inductance fraction and non-linearities and we determine the kinetic inductance fraction value that gives the lowest NEP.
[en] We report on theoretical studies of recently discovered radiation-induced resistance oscillations and zero resistance states in Hall bars when the irradiation frequency is very low. In this situation the photon energy is much smaller than the spacing between the Landau levels and therefore interlevel transitions are excluded. We apply the radiation-driven electron orbit model concluding that the resistance suppression is a manifestation of “long-wavelength” resistance oscillations where only one complete oscillation is observed
[en] A new approach to detect coherent modes using microwave reflectometry is presented. The proposed approach is based on the modulation of the reflecting layer in the poloidal direction due to the presence of rotating coherent MHD modes. The applicability of the approach is demonstrated, using either conventional or Doppler reflectometry, in plasmas with a high background turbulence level where the standard analysis method fails. (letter)
[en] One of the problems encountered in the application of reflectometry to fusion plasmas is that the transmit antenna must be aligned such that the reflected wave form is successfully collected by a suitably arranged receive antenna. This task is made even more difficult in the case of shaped plasmas, or when plasma motion is such that the incident wave is no longer normal to the plasma surface. One would ideally like to have antennas which may be steered in real time to compensate for changes in plasma shape and/or position. A program has been initiated at U.C. Davis to address this problem, and microwave beam steerers suitable for electronically scanned reflectometers have been developed. The approach taken has been to develop phased antenna array (PAA) concepts which operate over broad bandwidths. Laboratory test results of a proof-of-principle PAA system will be presented, along with a description of ongoing research activities by U.C. Davis in this field. copyright 1999 American Institute of Physics
[en] Studies on applications of microwave irradiation to organic synthesis published over 2000 - 2002 are surveyed. The theoretical concepts concerning the influence exerted by microwave irradiation on the course of organic reactions are briefly discussed.
[en] Quinolines are thermally stable and can be used as an excellent n-type semiconducting materials. Since quinolines are also known to be electron acceptor molecules, combination of various electron donor building blocks can be utilized in photonic and electronic organic light-emitting diode (OLED) applications. For example, donor.acceptor systems with phenothiazine (or carbazole) molecules as electron donors and the phenylquinoline group as an electron acceptor provide an efficient approach for the design of new materials exhibiting highly efficient charge-transfer photophysics and electroluminescence in OLEDs. We have described the Friedlander quinoline synthesis between aminobenzophenones and symmetrical diacetyl compounds having phenothiazine, carbazole, biphenyl, and phenyl moieties under solvent-free microwave irradiation in 12.98% isolated yields