15,677 research outputs found
Homomorphisms between fuzzy information systems revisited
Recently, Wang et al. discussed the properties of fuzzy information systems
under homomorphisms in the paper [C. Wang, D. Chen, L. Zhu, Homomorphisms
between fuzzy information systems, Applied Mathematics Letters 22 (2009)
1045-1050], where homomorphisms are based upon the concepts of consistent
functions and fuzzy relation mappings. In this paper, we classify consistent
functions as predecessor-consistent and successor-consistent, and then proceed
to present more properties of consistent functions. In addition, we improve
some characterizations of fuzzy relation mappings provided by Wang et al.Comment: 10 page
Doppler effect of gamma-ray bursts in the fireball framework
The influence of the Doppler effect in the fireball framework on the spectrum
of gamma-ray bursts is investigated. The study shows that the shape of the
expected spectrum of an expanding fireball remains almost the same as that of
the corresponding rest frame spectrum for constant radiations of the
bremsstrahlung, Comptonized, and synchrotron mechanisms as well as for that of
the GRB model. The peak flux spectrum and the peak frequency are obviously
correlated. When the value of the Lorentz factor becomes 10 times larger, the
flux of fireballs would be several orders of magnitude larger. The expansion
speed of fireballs is a fundamental factor of the enhancement of the flux of
gamma-ray bursts.Comment: 19 pages, 13 figure
The influence of a single defect in composite gate insulators on the performance of nanotube transistors
The current through a carbon nanotube field-effect transistor (CNFET) with
cylindrical gate electrode is calculated using the nonequilibrium Greens
function method in a tight-binding approximation. The obtained result is in
good agreement with the experimental data. The space radiation and nuclear
radiation are known to cause defects in solids. The theoretical approach is
used to calculate the amplitude of the random-telegraph-signal (RTS) noise due
to a single defect in the gate oxide of a long channel p-type CNFET. We
investigate how the amplitude of the RTS noise is affected by the composite
structure of gate insulators, which contains an inner insulator with a
dielectric constant larger than 3.9 and an outer insulator with a dielectric
constant of 3.9 (as for SiO2). It is found that the RTS amplitude increases
apparently with the decreasing thickness of the inner gate insulator. If the
inner insulator is too thin, even though its dielectric constant is as large as
80, the amplitude of the RTS noise caused by the charge of Q = +1e may amount
to around 80% in the turn-on region. Due to strong effects of defects in
CNFETs, CNFETs have a potential to be used for detecting the space radiation or
nuclear radiation.Comment: 8 Figure
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