165 research outputs found
Deep sound-field denoiser: optically-measured sound-field denoising using deep neural network
This paper proposes a deep sound-field denoiser, a deep neural network (DNN)
based denoising of optically measured sound-field images. Sound-field imaging
using optical methods has gained considerable attention due to its ability to
achieve high-spatial-resolution imaging of acoustic phenomena that conventional
acoustic sensors cannot accomplish. However, the optically measured sound-field
images are often heavily contaminated by noise because of the low sensitivity
of optical interferometric measurements to airborne sound. Here, we propose a
DNN-based sound-field denoising method. Time-varying sound-field image
sequences are decomposed into harmonic complex-amplitude images by using a
time-directional Fourier transform. The complex images are converted into
two-channel images consisting of real and imaginary parts and denoised by a
nonlinear-activation-free network. The network is trained on a sound-field
dataset obtained from numerical acoustic simulations with randomized
parameters. We compared the method with conventional ones, such as image
filters and a spatiotemporal filter, on numerical and experimental data. The
experimental data were measured by parallel phase-shifting interferometry and
holographic speckle interferometry. The proposed deep sound-field denoiser
significantly outperformed the conventional methods on both the numerical and
experimental data.Comment: 13 pages, 8 figures, 2 table
Plasmid Construction Using Recombination Activity in the Fission Yeast Schizosaccharomyces pombe
BACKGROUND: Construction of plasmids is crucial in modern genetic manipulation. As of now, the common method for constructing plasmids is to digest specific DNA sequences with restriction enzymes and to ligate the resulting DNA fragments with DNA ligase. Another potent method to construct plasmids, known as gap-repair cloning (GRC), is commonly used in the budding yeast Saccharomyces cerevisiae. GRC makes use of the homologous recombination activity that occurs within the yeast cells. Due to its flexible design and efficiency, GRC has been frequently used for constructing plasmids with complex structures as well as genome-wide plasmid collections. Although there have been reports indicating GRC feasibility in the fission yeast Schizosaccharomyces pombe, this species is not commonly used for GRC as systematic studies of reporting GRC efficiency in S. pombe have not been performed till date. METHODOLOGY/PRINCIPAL FINDINGS: We investigated GRC efficiency in S. pombe in this study. We first showed that GRC was feasible in S. pombe by constructing a plasmid that contained the LEU2 auxotrophic marker gene in vivo and showed sufficient efficiency with short homology sequences (>25 bp). No preference was shown for the sequence length from the cut site in the vector plasmid. We next showed that plasmids could be constructed in a proper way using 3 DNA fragments with 70% efficiency without any specific selections being made. The GRC efficiency with 3 DNA fragments was dramatically increased >95% in lig4Delta mutant cell, where non-homologous end joining is deficient. Following this approach, we successfully constructed plasmid vectors with leu1+, ade6+, his5+, and lys1+ markers with the low-copy stable plasmid pDblet as a backbone by applying GRC in S. pombe. CONCLUSIONS/SIGNIFICANCE: We concluded that GRC was sufficiently feasible in S. pombe for genome-wide gene functional analysis as well as for regular plasmid construction. Plasmids with different markers constructed in this research are available from NBRP-yeast (http://yeast.lab.nig.ac.jp/)
Low-energy excitations in a one-dimensional orthogonal dimer model with the Dzyaloshinski-Moriya interaction
Effects of the Dzyaloshinski-Moriya (DM) interaction on low-energy
excitations in a one-dimensional orthogonal-dimer model are studied by using
the perturbation expansions and the numerical diagonalization method. In the
absence of the DM interaction, the triplet excitations show two flat spectra
with three-fold degeneracy, which are labeled by magnetization .
These spectra split into two branches with M=0 and with by
switching-on of the DM interaction and besides the curvature appears in the
triplet excitations with more strongly than those of M=0.Comment: 4 pages, 2 figures, Proceeding for The 9th ISSP International
Symposium (ISSP-9) on Quantum Condensed System (Nov. 2004
Spin Dynamics in Iron-based Layered Superconductor (La_{0.87}Ca_{0.13})FePO Revealed by ^{31}P and ^{139}La NMR Studies
We report ^{31}P and ^{139}La NMR studies of (La_{0.87}Ca_{0.13})FePO, which
is a family member of the recently discovered superconductor
LaFeAs(O_{1-x}F_x). In the normal state, Knight shift and show that a
Fermi-liquid state with moderate ferromagnetic fluctuations emerges below 30K.
From 1/T_1T of ^{31}P and ^{139}La, quasi-two dimensional electronic
structure is suggested, in which the FeP layer is more conductive than the LaO
layer. In the superconducting (SC) state, although a clear Meissner signal was
observed, 1/T_1T increases below T_c, in contrast to a decrease of 1/T_1T due
to the opening of a SC gap, suggesting that novel low-energy spin dynamics
develop in the SC state.Comment: Phys. Rev. Lett. 101, 077006 (2008
- …