PRl Modulation Type Recognition Using Level Clustering and Autocorrelation

We conducted a modeling study of the threading dislocation behavior in chirped and unchirped InGaAs/GaAs (001) strained-layer superlattices (SLSs) using a Dodson & Tsao / Kujofsa & Ayers (DTKA) type plastic flow model. Four types of SLSs were investigated: type I was chirped using compositional modulation, type II was chirped using layer thickness modulation, type III was unchirped with alternating layers of InGaAs and GaAs, and type IV was unchirped with alternating layers of InGaAs having two different compositions. Generally the surface and average values of the dislocation density decreased with increasing total thickness. The dependence on top indium composition was more complex, due to dislocation compensation and multiplication effects, but for type II and IV superlattices, the average and surface threading dislocation densities increased in nearly monotonic fashion with top indium composition. Based on these results, the compositionally-modulated chirped (type I) and InGaAs/GaAs unchirped (type III) superlattices appear to be best suited as buffer layers for metamorphic devices, while the chirped superlattices with layer thickness modulation (type II) and InGaAs/InGaAs unchirped (type IV) superlattices appear to be poorly suited for use as buffer layers for devices containing high indium content.

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25. Intensities of the discrete sources in Cassiopeia, Cygnus and Taurus at Λ 3·2 cm.

Symposium - International Astronomical Union ◽

10.1017/s0074180900049007 ◽

1957 ◽

Vol 4 ◽

pp. 155-155

Author(s):

V. A. Razin ◽

V. M. Pletchkov

Keyword(s):

Radio Emission ◽

Main Part ◽

Solar Radio ◽

Effective Area ◽

Solar Radio Emission ◽

Modulation Type ◽

Method Of Measurement ◽

Half Power ◽

Astronomical Station ◽

Polarized Radiation

Measurements of the intensities of radio emission from the three most powerful discrete sources were carried out early in 1955 at the Gorky radio astronomical station ‘Zimenky’ (latitude 56° 9·5′). The arrangement used for these measurements is described elsewhere [1]. The main part of the aerial consists of a paraboloid, 4 metres in diameter, on an alt-azimuth mounting. The beam has an opening (between half-power points) equal to 32′. The effective area of the aerial was determined by comparison with the standard megaphone antenna for solar radio emission [2] and equals 10 m.2. The efficiency of the aerial is determined according to the method of measurement of the proper radio emission of the aerial [3]. The reception device is of a modulation type. The fluctuation threshold of the sensitivity of the device for the used time constant of 20 sec. equals 0°·6 C., which corresponds to a flux of non-polarized radiation of 1·65 × 10−24 w.m.−2 (c./s.)−1 reaching the aerial.

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