9,668 research outputs found
A Coupled AKNS-Kaup-Newell Soliton Hierarchy
A coupled AKNS-Kaup-Newell hierarchy of systems of soliton equations is
proposed in terms of hereditary symmetry operators resulted from Hamiltonian
pairs. Zero curvature representations and tri-Hamiltonian structures are
established for all coupled AKNS-Kaup-Newell systems in the hierarchy.
Therefore all systems have infinitely many commuting symmetries and
conservation laws. Two reductions of the systems lead to the AKNS hierarchy and
the Kaup-Newell hierarchy, and thus those two soliton hierarchies also possess
tri-Hamiltonian structures.Comment: 15 pages, late
Domain structure in the monoclinic Pm phase of Pb(Mg1/3Nb2/3)O3 - PbTiO3 single crystals
The domain structure of (1-x)Pb(Mg1/3Nb2/3)O3- xPbTiO3 single crystals with
composition x ~ 0.33 in the range of the morphotropic phase boundary (MPB) was
studied. Based on the analysis of spontaneous strain compatibility and charge
of domain walls, we have established the permissible domain arrangements for
the ferroelectric phases of different symmetry, which are expected to occur in
the range of the MPB. Examination of (001)-oriented unpoled and electrically
poled (along the [001] direction) crystal plates in polarizing microscope
reveals a monophase state with the domain structure compatible with the
structure theoretically predicted for the Mc monoclinic phase (space group Pm),
which was recently discovered in the compositions close to the MPB by x-ray and
neutron diffraction studies. In the unpoled crystal the 180 deg. walls between
the domains whose spontaneous polarization vectors are parallel to the plane of
the crystal plate (i.e. a-domains) are observed. The domain structure of the
poled crystal is predominantly composed of crystallographically prominent Wf
walls parallel to (001) (i.e. the plane of the crystal plate) and inclined S
walls parallel to [110] or [1-10] direction. In poled and unpoled samples the
optical rotatory polarization effect is found, which is related to the
inhomogeneity of the sample resulting from the mixture of domains.Comment: PDF file, 30 pages, 15 figures (3 in color) collected on pp.18-3
Molecular Physiological Characterization of a High Heat Resistant Spore Forming <i>Bacillus subtilis</i> Food Isolate
Binary Nonlinearization of Lax pairs of Kaup-Newell Soliton Hierarchy
Kaup-Newell soliton hierarchy is derived from a kind of Lax pairs different
from the original ones. Binary nonlinearization procedure corresponding to the
Bargmann symmetry constraint is carried out for those Lax pairs. The proposed
Lax pairs together with adjoint Lax pairs are constrained as a hierarchy of
commutative, finite dimensional integrable Hamiltonian systems in the Liouville
sense, which also provides us with new examples of finite dimensional
integrable Hamiltonian systems. A sort of involutive solutions to the
Kaup-Newell hierarchy are exhibited through the obtained finite dimensional
integrable systems and the general involutive system engendered by binary
nonlinearization is reduced to a specific involutive system generated by
mono-nonlinearization.Comment: 15 pages, plain+ams tex, to be published in Il Nuovo Cimento
Specific heats of dilute neon inside long single-walled carbon nanotube and related problems
An elegant formula for coordinates of carbon atoms in a unit cell of a
single-walled nanotube (SWNT) is presented and the potential of neon (Ne)
inside an infinitely long SWNT is analytically derived out under the condition
of the Lennard-Jones potential between Ne and carbon atoms.
Specific heats of dilute Ne inside long (20, 20) SWNT are calculated at
different temperatures. It is found that Ne exhibits 3-dimensional (3D) gas
behavior at high temperature but behaves as 2D gas at low temperature.
Especially, at ultra low temperature, Ne inside (20, 20) nanotubes behaves as
lattice gas. A coarse method to determine the characteristic temperature
for low density gas in a potential is put forward. If
, we just need to use the classical statistical
mechanics without solving the Shr\"{o}dinger equation to consider the thermal
behavior of gas in the potential. But if , we
must solve the Shr\"{o}dinger equation. For Ne in (20,20) nanotube, we obtain
K.Comment: 14 pages, 7 figure
Probing Quantum Hall Pseudospin Ferromagnet by Resistively Detected NMR
Resistively Detected Nuclear Magnetic Resonance (RD-NMR) has been used to
investigate a two-subband electron system in a regime where quantum Hall
pseudo-spin ferromagnetic (QHPF) states are prominently developed. It reveals
that the easy-axis QHPF state around the total filling factor can be
detected by the RD-NMR measurement. Approaching one of the Landau level (LL)
crossing points, the RD-NMR signal strength and the nuclear spin relaxation
rate enhance significantly, a signature of low energy spin
excitations. However, the RD-NMR signal at another identical LL crossing point
is surprisingly missing which presents a puzzle
Classical Poisson structures and r-matrices from constrained flows
We construct the classical Poisson structure and -matrix for some finite
dimensional integrable Hamiltonian systems obtained by constraining the flows
of soliton equations in a certain way. This approach allows one to produce new
kinds of classical, dynamical Yang-Baxter structures. To illustrate the method
we present the -matrices associated with the constrained flows of the
Kaup-Newell, KdV, AKNS, WKI and TG hierarchies, all generated by a
2-dimensional eigenvalue problem. Some of the obtained -matrices depend only
on the spectral parameters, but others depend also on the dynamical variables.
For consistency they have to obey a classical Yang-Baxter-type equation,
possibly with dynamical extra terms.Comment: 16 pages in LaTe
miRNA-1-3p is an early embryonic male sex-determining factor in the Oriental fruit fly Bactrocera dorsalis
Regulation of male sexual differentiation by a Y chromosome-linked male determining factor (M-factor) is one of a diverse array of sex determination mechanisms found in insects. By deep sequencing of small RNAs from Bactrocera dorsalis early embryos, we identified an autosomal-derived microRNA, miR-1-3p, that has predicted target sites in the transformer gene (Bdtra) required for female sex determination. We further demonstrate by both in vitro and in vivo tests that miR-1-3p suppresses Bdtra expression. Injection of a miR-1-3p mimic in early embryos results in 87–92% phenotypic males, whereas knockdown of miR-1-3p by an inhibitor results in 67–77% phenotypic females. Finally, CRISPR/Cas9-mediated knockout of miR-1-3p results in the expression of female-specific splice variants of Bdtra and doublesex (Bddsx), and induced sex reversal of XY individuals into phenotypic females. These results indicate that miR-1-3p is required for male sex determination in early embryogenesis in B. dorsalis as an intermediate male determiner
- …