53,824 research outputs found
Representations and classification of traveling wave solutions to Sinh-G{\"o}rdon equation
Two concepts named atom solution and combinatory solution are defined. The
classification of all single traveling wave atom solutions to Sinh-G{\"o}rdon
equation is obtained, and qualitative properties of solutions are discussed. In
particular, we point out that some qualitative properties derived intuitively
from dynamic system method aren't true. In final, we prove that our solutions
to Sinh-G{\"o}rdon equation include all solutions obtained in the paper[Fu Z T
et al, Commu. in Theor. Phys.(Beijing) 2006 45 55]. Through an example, we show
how to give some new identities on Jacobian elliptic functions.Comment: 12 pages. accepted by Communications in theoretical physics (Beijing
Han's Bijection via Permutation Codes
We show that Han's bijection when restricted to permutations can be carried
out in terms of the cyclic major code and the cyclic inversion code. In other
words, it maps a permutation with a cyclic major code to a permutation with a cyclic inversion code . We also show that the fixed points of Han's map can be characterized by
the strong fixed points of Foata's second fundamental transformation. The
notion of strong fixed points is related to partial Foata maps introduced by
Bj\"orner and Wachs.Comment: 12 pages, to appear in European J. Combi
Protein-mediated DNA Loop Formation and Breakdown in a Fluctuating Environment
Living cells provide a fluctuating, out-of-equilibrium environment in which
genes must coordinate cellular function. DNA looping, which is a common means
of regulating transcription, is very much a stochastic process; the loops arise
from the thermal motion of the DNA and other fluctuations of the cellular
environment. We present single-molecule measurements of DNA loop formation and
breakdown when an artificial fluctuating force, applied to mimic a fluctuating
cellular environment, is imposed on the DNA. We show that loop formation is
greatly enhanced in the presence of noise of only a fraction of , yet
find that hypothetical regulatory schemes that employ mechanical tension in the
DNA--as a sensitive switch to control transcription--can be surprisingly robust
due to a fortuitous cancellation of noise effects
Fracture strength and Young's modulus of ZnO nanowires
The fracture strength of ZnO nanowires vertically grown on sapphire
substrates was measured in tensile and bending experiments. Nanowires with
diameters between 60 and 310 nm and a typical length of 2 um were manipulated
with an atomic force microscopy tip mounted on a nanomanipulator inside a
scanning electron microscope. The fracture strain of (7.7 +- 0.8)% measured in
the bending test was found close to the theoretical limit of 10% and revealed a
strength about twice as high as in the tensile test. From the tensile
experiments the Young's modulus could be measured to be within 30% of that of
bulk ZnO, contrary to the lower values found in literature.Comment: 5 pages, 3 figures, 1 tabl
Optoelectronics of Inverted Type-I CdS/CdSe Core/Crown Quantum Ring
Inverted type-I heterostructure core/crown quantum rings (QRs) are
quantum-efficient luminophores, whose spectral characteristics are highly
tunable. Here, we study the optoelectronic properties of type-I core/crown
CdS/CdSe QRs in the zincblende phase - over contrasting lateral size and crown
width. For this we inspect their strain profiles, transition energies,
transition matrix elements, spatial charge densities, electronic bandstructure,
band-mixing probabilities, optical gain spectra, maximum optical gains and
differential optical gains. Our framework uses an effective-mass envelope
function theory based on the 8-band kp method employing the valence
force field model for calculating the atomic strain distributions. The gain
calculations are based on the density-matrix equation and take into
consideration the excitonic effects with intraband scattering. Variations in
the QR lateral size and relative widths of core and crown (ergo the
composition) affect their energy levels, band-mixing probabilities, optical
transition matrix elements, emission wavelengths/intensity, etc. The optical
gain of QRs is also strongly dimension and composition dependent with further
dependency on the injection carrier density causing band-filling effect. They
also affect the maximum and differential gain at varying dimensions and
compositions.Comment: Published in AIP Journal of Applied Physics (11 pages, 7 figures
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