3,986 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
Detection of Giant Pulses from the Pulsar PSR B0031-07
Giant pulses have been detected from the pulsar PSR B0031-07. A pulse with an
intensity higher than the intensity of the average pulse by a factor of 50 or
more is encountered approximately once per 300 observed periods. The peak flux
density of the strongest pulse is 530 Jy, which is a factor of 120 higher than
the peak flux density of the average pulse. The giant pulses are a factor of 20
narrower than the integrated profile and are clustered about its center.Comment: 7 pages, 2 figures, to appear in: Pis'ma v Astronomicheskii Zhurnal,
2004, v.30, No.4, and will be translated as: Astronomy Letters, v.30, No.
ДОСЛІДЖЕННЯ ВПЛИВУ ХАОТИЧНОГО СТРУМУ ЕЛЕКТРОНІВ НА ПАРАМЕТРИ ЕЛЕКТРИЧНОГО ПОЛЯ У ПРИАНОДНІЙ ЗОНІ РОЗРЯДУ
The influence of the ratio of the discharge density and chaotic electronic currents on the potential drop in the diffusion zone near the anode was considered. The analysis of the influence of forced convection on the conditions of existence of a stable diffuse discharge on the anode surface was performedРассмотрено влияние соотношения плотности разрядного и хаотического электронных токов на падение потенциала в диффузионной зоне прианодной области. Выполнен анализ влияния вынужденной конвекции на условия существования устойчивого диффузного разряда на поверхности анода.Розглянуто вплив співвідношення густини розрядного та хаотичного електронних струмів на падіння потенціалу у дифузійній зоні прианодної області. Виконано аналіз впливу вимушеної конвекції на умови існування стійкого дифузного розряду на поверхні анода
Excitations in the Halo Nucleus He-6 Following The Li-7(gamma,p)He-6 Reaction
A broad excited state was observed in 6-He with energy E_x = 5 +/- 1 MeV and
width Gamma = 3 +/- 1 MeV, following the reaction Li-7(gamma,p)He-6. The state
is consistent with a number of broad resonances predicted by recent cluster
model calculations. The well-established reaction mechanism, combined with a
simple and transparent analysis procedure confers considerable validity to this
observation.Comment: 3 pages of LaTeX, 3 figures in PostScript, approved for publication
in Phys. Rev. C, August, 200
Anode off-gas recirculation ejector modelling at various operation modes
The article includes methods for calculation of the anode off-gas equilibrium chemical composition, anode off-gas recirculation ratio at which the carbon deposition fails to occur in the reformer and fuel cell anode channel and the ejector’s entrainment ratio for the SOFC power unit with anode off-gas recirculation at various operation modes.В статье приведены методики расчета состава уходящего анодного газа, степени рециркуляции, обеспечивающей протекание реакций риформинга с отсутствием сажеобразования, а также коэффициента инжекции эжектора в схеме с рециркуляцией анодных газов для различных режимов работы установки
Three-body correlations in direct reactions: Example of Be populated in reaction
The Be continuum states were populated in the charge-exchange reaction
H(Li,Be) collecting very high statistics data ( events) on the three-body ++ correlations. The
Be excitation energy region below MeV is considered, where the
data are dominated by contributions from the and states. It is
demonstrated how the high-statistics few-body correlation data can be used to
extract detailed information on the reaction mechanism. Such a derivation is
based on the fact that highly spin-aligned states are typically populated in
the direct reactions.Comment: submitted to Physical Review
The gene-expression profile of renal medulla in ISIAH rats with inherited stress-induced arterial hypertension
Metabolic pathways enriched with genes differentially expressed in ISIAH and WAG renal medulla. (XLS 41 kb
Ultimate performance of Quantum Well Infrared Photodetectors in the tunneling regime
Thanks to their wavelength diversity and to their excellent uniformity,
Quantum Well Infrared Photodetectors (QWIP) emerge as potential candidates for
astronomical or defense applications in the very long wavelength infrared
(VLWIR) spectral domain. However, these applications deal with very low
backgrounds and are very stringent on dark current requirements. In this paper,
we present the full electro-optical characterization of a 15 micrometer QWIP,
with emphasis on the dark current measurements. Data exhibit striking features,
such as a plateau regime in the IV curves at low temperature (4 to 25 K). We
show that present theories fail to describe this phenomenon and establish the
need for a fully microscopic approach
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