77 research outputs found
Instantaneous Radio Spectra of Giant Pulses from the Crab Pulsar from Decimeter to Decameter Wavelengths
The results of simultaneous multifrequency observations of giant radio pulses
from the Crab pulsar, PSR B0531+21, at 23, 111, and 600 MHz are presented and
analyzed. Giant pulses were detected at a frequency as low as 23 MHz for the
first time. Of the 45 giant pulses detected at 23 MHz, 12 were identified with
counterparts observed simultaneously at 600 MHz. Of the 128 giant pulses
detected at 111 MHz, 21 were identified with counterparts observed
simultaneously at 600 MHz. The spectral indices for the power-law frequency
dependence of the giant-pulse energies are from -3.1 to -1.6. The mean spectral
index is -2.7 +/- 0.1 and is the same for both frequency combinations (600-111
MHz and 600-23 MHz). The large scatter in the spectral indices of the
individual pulses and the large number of unidentified giant pulses suggest
that the spectra of the individual giant pulses do not actually follow a simple
power law. The observed shapes of the giant pulses at all three frequencies are
determined by scattering on interstellar plasma irregularities. The scatter
broadening of the pulses and its frequency dependence were determined as
tau_sc=20*(f/100)^(-3.5 +/- 0.1) ms, where the frequency f is in MHz.Comment: 13 pages, 1 figure, 1 table (originally published in Russian in
Astronomicheskii Zhurnal, 2006, vol. 83, No. 7, pp. 630-637), translated by
Georgii Rudnitski
Examination of Processes of Cultivation of <i>V. cholerae</i> strains - Producers of Protective Antigens of Cholera Bivalent Chemical Vaccine in Tablets - in the Engineered Bioreactor
Studied is the kinetics of major antigen accumulation at growing of Vibrio cholerae M-41 Ogawa and 569 B Inaba strains in industrial and engineered reactors. Demonstrated is the possibility to obtain conditional native protective antigens in the engineered bioreactor. Shown is the identity of physiological and morphological properties of industrial Vibrio cholerae strains during their submerged cultivation in industrial and engineered bioreactors. Cholera bivalent chemical vaccine obtained using engineered bioreactor possesses quality indices meeting the requirements of normative documents and equal to those of preparation received by traditional approach
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