41,440 research outputs found
Integrable dispersionless KdV hierarchy with sources
An integrable dispersionless KdV hierarchy with sources (dKdVHWS) is derived.
Lax pair equations and bi-Hamiltonian formulation for dKdVHWS are formulated.
Hodograph solution for the dispersionless KdV equation with sources (dKdVWS) is
obtained via hodograph transformation. Furthermore, the dispersionless
Gelfand-Dickey hierarchy with sources (dGDHWS) is presented.Comment: 15 pages, to be published in J. Phys. A: Math. Ge
Single-particle subband structure of Quantum Cables
We proposed a model of Quantum Cable in analogy to the recently synthesized
coaxial nanocable structure [Suenaga et al. Science, 278, 653 (1997); Zhang et
al. ibid, 281, 973 (1998)], and studied its single-electron subband structure.
Our results show that the subband spectrum of Quantum Cable is different from
either double-quantum-wire (DQW) structure in two-dimensional electron gas
(2DEG) or single quantum cylinder. Besides the double degeneracy of subbands
arisen from the non-abelian mirrow reflection symmetry, interesting
quasicrossings (accidental degeneracies), anticrossings and bundlings of
Quantum Cable energy subbands are observed for some structure parameters. In
the extreme limit (barrier width tends to infinity), the normal degeneracy of
subbands different from the DQW structure is independent on the other structure
parameters.Comment: 12 pages, 9 figure
Quantum Cable as transport spectroscopy of 1D DOS of cylindrical quantum wires
We considered the proposed Quantum Cable as a kind of transport spectroscopy
of one-dimensional (1D) density of states (DOS) of cylindrical quantum wires.
By simultaneously detecting the direct current through the cylindrical quantum
wire and the leaked tunneling current into the neighboring wire at desired
temperatures, one can obtain detailed information about 1D DOS and subband
structure of cylindrical quantum wires.Comment: 7 pages, 4 figures, late
Separation of variables for soliton equations via their binary constrained flows
Binary constrained flows of soliton equations admitting Lax
matrices have 2N degrees of freedom, which is twice as many as degrees of
freedom in the case of mono-constrained flows. For their separation of
variables only N pairs of canonical separated variables can be introduced via
their Lax matrices by using the normal method. A new method to introduce the
other N pairs of canonical separated variables and additional separated
equations is proposed. The Jacobi inversion problems for binary constrained
flows are established. Finally, the factorization of soliton equations by two
commuting binary constrained flows and the separability of binary constrained
flows enable us to construct the Jacobi inversion problems for some soliton
hierarchies.Comment: 39 pages, Amste
Ballistic electronic transport in Quantum Cables
We studied theoretically ballistic electronic transport in a proposed
mesoscopic structure - Quantum Cable. Our results demonstrated that Qauntum
Cable is a unique structure for the study of mesoscopic transport. As a
function of Fermi energy, Ballistic conductance exhibits interesting stepwise
features. Besides the steps of one or two quantum conductance units (),
conductance plateaus of more than two quantum conductance units can also be
expected due to the accidental degeneracies (crossings) of subbands. As
structure parameters is varied, conductance width displays oscillatory
properties arising from the inhomogeneous variation of energy difference
betweeen adjoining transverse subbands. In the weak coupling limits,
conductance steps of height becomes the first and second plateaus for
the Quantum Cable of two cylinder wires with the same width.Comment: 11 pages, 5 figure
On the Toda Lattice Equation with Self-Consistent Sources
The Toda lattice hierarchy with self-consistent sources and their Lax
representation are derived. We construct a forward Darboux transformation (FDT)
with arbitrary functions of time and a generalized forward Darboux
transformation (GFDT) for Toda lattice with self-consistent sources (TLSCS),
which can serve as a non-auto-Backlund transformation between TLSCS with
different degrees of sources. With the help of such DT, we can construct many
type of solutions to TLSCS, such as rational solution, solitons, positons,
negetons, and soliton-positons, soliton-negatons, positon-negatons etc., and
study properties and interactions of these solutions.Comment: 20 page
The Degasperis-Procesi equation with self-consistent sources
The Degasperis-Procesi equation with self-consistent sources(DPESCS) is
derived. The Lax representation and the conservation laws for DPESCS are
constructed. The peakon solution of DPESCS is obtained.Comment: 15 page
Compact and High Performance Dual-band Bandpass Filter Using Resonator-embedded Scheme for WLANs
A compact microstrip dual-band bandpass filter (DBBPF) with high selectivity and good suppression for wireless local area networks (WLANs) is proposed utilizing a novel embedded scheme resonator. Two passbands are produced by a pair of embedded half-wavelength meandered stepped-impedance resonator (MSIR) and a quadwavelength short stub loaded stepped-impedance resonator (SIR) separately. The resonator is fed by folded Tshaped capacitive source-load coupling microstrip feed line, and four transmission zeros are obtained at both sides of the bands to improve selectivity and suppression. Simultaneously, the size of the filter is extermely compact because embedding half-wavelength MSIR only changes the interior configuration of quad-wavelength SIR. To validate the design method, the designed filter is fabricated and measured. Both simulated and measured results indicate that good transmission property has been achieved
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