1,188 research outputs found
Feasibility of an Incoherent-scatter Radar Aboard the Space Shuttle
The results of a preliminary study to investigate the feasibility of conducting an incoherent scatter radar experiment on board the space shuttle are presented. The results indicate that such an experiment is technically feasible. The more difficult questions to answer are whether the system can be made flexible enough to justify the problems and costs involved. The design parameters and the tradeoffs that are available in the consideration of these questions are evaluated. Some of the more serious limitations pertain to: (1) the presence of ground clutter and F region auroral clutter; (2) available average power; (3) weight and volume associated with required antenna size, transmitter, and energy storage devices; and (4) antenna breakdown associated with high power transmitter problems
Double-sided coaxial circuit QED with out-of-plane wiring
Superconducting circuits are well established as a strong candidate platform
for the development of quantum computing. In order to advance to a practically
useful level, architectures are needed which combine arrays of many qubits with
selective qubit control and readout, without compromising on coherence. Here we
present a coaxial circuit QED architecture in which qubit and resonator are
fabricated on opposing sides of a single chip, and control and readout wiring
are provided by coaxial wiring running perpendicular to the chip plane. We
present characterisation measurements of a fabricated device in good agreement
with simulated parameters and demonstrating energy relaxation and dephasing
times of s and s respectively. The architecture
allows for scaling to large arrays of selectively controlled and measured
qubits with the advantage of all wiring being out of the plane.Comment: 4 pages, 3 figures, 1 tabl
Cu-NMR study on the disordered quantum spin magnet with the Bose-glass ground state
Cu-NMR study has been performed on the disordered spin-gap system
Tl1-xKxCuCl3 In the high-field H > HC=\Delta/\mu_B, where \Delta is the
spin-gap, the hyperfine field becomes extremely inhomogeneous at low
temperatures due to the field-induced magnetic order, indicating that the
ordered spin state must be different from the pure TlCuCl3. In the low field H
< HC, a saturating behavior in the longitudinal nuclear spin relaxation rate
1/T1 was observed at low temperatures, indicating existence of the magnetic
ground state proposed to be Bose-glass phase by Fisher.Comment: RHMF200
Protein fold recognition using HMM–HMM alignment and dynamic programming
Detecting three dimensional structures of protein sequences is a challenging task in biological sciences.
For this purpose, protein fold recognition has been utilized as an intermediate step which helps in
classifying a novel protein sequence into one of its folds. The process of protein fold recognition
encompasses feature extraction of protein sequences and feature identification through suitable classi-
fiers. Several feature extractors are developed to retrieve useful information from protein sequences.
These features are generally extracted by constituting protein’s sequential, physicochemical and evolutionary
properties. The performance in terms of recognition accuracy has also been gradually improved over the last decade. However, it is yet to reach a well reasonable and accepted level. In this work, we first applied HMM–HMM alignment of protein sequence from HHblits to extract profile HMM (PHMM) matrix. Then we computed the distance between respective PHMM matrices using kernalized dynamic
programming. We have recorded significant improvement in fold recognition over the state-of-the-art feature extractors. The improvement of recognition accuracy is in the range of 2.7–11.6% when experimented on three benchmark datasets from Structural Classification of Proteins
Vibrational properties of phonons in random binary alloys: An augmented space recursive technique in the k-representation
We present here an augmented space recursive technique in the
k-representation which include diagonal, off-diagonal and the environmental
disorder explicitly : an analytic, translationally invariant, multiple
scattering theory for phonons in random binary alloys.We propose the augmented
space recursion (ASR) as a computationally fast and accurate technique which
will incorporate configuration fluctuations over a large local environment. We
apply the formalism to , Ni_{88}Cr_12} and
alloys which is not a random choice. Numerical results on spectral functions,
coherent structure factors, dispersion curves and disordered induced FWHM's are
presented. Finally the results are compared with the recent itinerant coherent
potential approximation (ICPA) and also with experiments.Comment: 20 pages, LaTeX, 23 figure
A theoretical investigation of ferromagnetic tunnel junctions with 4-valued conductances
In considering a novel function in ferromagnetic tunnel junctions consisting
of ferromagnet(FM)/barrier/FM junctions, we theoretically investigate multiple
valued (or multi-level) cell property, which is in principle realized by
sensing conductances of four states recorded with magnetization configurations
of two FMs; that is, (up,up), (up,down), (down,up), (down,down). To obtain such
4-valued conductances, we propose FM1/spin-polarized barrier/FM2 junctions,
where the FM1 and FM2 are different ferromagnets, and the barrier has spin
dependence. The proposed idea is applied to the case of the barrier having
localized spins. Assuming that all the localized spins are pinned parallel to
magnetization axes of the FM1 and FM2, 4-valued conductances are explicitly
obtained for the case of many localized spins. Furthermore, objectives for an
ideal spin-polarized barrier are discussed.Comment: 9 pages, 3 figures, accepted for publication in J. Phys.: Condens.
Matte
Phase transition in the collisionless regime for wave-particle interaction
Gibbs statistical mechanics is derived for the Hamiltonian system coupling
self-consistently a wave to N particles. This identifies Landau damping with a
regime where a second order phase transition occurs. For nonequilibrium initial
data with warm particles, a critical initial wave intensity is found: above it,
thermodynamics predicts a finite wave amplitude in the limit of infinite N;
below it, the equilibrium amplitude vanishes. Simulations support these
predictions providing new insight on the long-time nonlinear fate of the wave
due to Landau damping in plasmas.Comment: 12 pages (RevTeX), 2 figures (PostScript
- …