Showing papers by "Matsuo Sekine published in 1997"
01 Jun 1997
TL;DR: In this article, a Weibull raindrop-size distribution was proposed by fitting the measurements of rainfall observed using a distrometer in Tokyo, and a propagation experiment at 103 GHz was introduced.
Abstract: In the design of radio systems such as terrestrial and satellite communication links at frequencies above 10 GHz, rain attenuation is an important problem. A Weibull raindrop-size distribution is proposed by fitting the measurements of rainfall observed using a distrometer in Tokyo. A propagation experiment at 103 GHz is introduced. Rain attenuation coefficients are calculated by considering the Mie scattering using this Weibull distribution for raindrop size and are compared with some experimental data. The results of frequency characteristics from this Weibull raindrop-size distribution agrees well with some experimental data for the range 8–312.5 GHz.
56 citations
Journal Article•
7 citations
15 Apr 1997
TL;DR: In this paper, an optical detector based on patterned YBa2Cu3O7-(delta ) thin films was demonstrated using two wavelength lasers and the amplitude of the light was modulated up to 18 GHz by an optical heterodyne mixing system.
Abstract: We have demonstrated an optical detector based on patterned YBa2Cu3O7-(delta ) thin films. The responses up to 18 GHz were observed using two wavelength lasers. The amplitude of the light was modulated up to 18 GHz by an optical heterodyne mixing system. The responsivity of the detectors is over 50 V/W for different wavelength lasers below 1 Hz and the responsivity is 4 mV/W at the 780 nm wavelength and 30 mV/W at 1.5 micrometers in the region from 3 GHz to 18 GHz. Our detector is one of the promising candidates for highly sensitive and wideband optical receiver.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
2 citations
TL;DR: Based on a preon model satisfying both the SU(2) and Lorentz invariances, it was shown that CP is violated, and anomalies are also eliminated as discussed by the authors.
Abstract: Based on a preon model satisfying both theSU(2) and Lorentz invariances, it is shown thatCP is violated, and anomalies are also eliminated.
2 citations
TL;DR: In this paper, a simple Lagrangian which is constructed by only the preon and antipreon fields was considered, and it was shown that φμ, φ€€€ Æ€ € Æ € À Æ, φ € Ã Æ and ϕμ correspond to the electroweak gauge bosons of preons and antipreons.
Abstract: We consider a simple Lagrangian which is constructed by only the preon and antipreon fields. By introducing the auxiliary fields φμ, φ
μ
†
, and ϕμ, it is shown that φμ, φ
μ
†
, and ϕμ correspond to the electroweak gauge bosonsW
μ
+
,W
μ
−
, andW
μ
3
, respectively, which are composite particles of preons and antipreons.
1 citations