1,063 research outputs found
Unveiling the Intricate Symphony of Nonlinear Pulsation Mode Interactions in High-Amplitude Scuti Stars
People can diagnose the interiors of stars by sensing their pulsations.
Pulsation modes, which are determined by the internal state and structure of a
star, are typically considered stable over short timescales. These independent
pulsation modes have been used in asteroseismology to reconstruct the interior
structure of stars. Here, we report the discovery of peculiar pulsation mode
interaction details in the high-amplitude Scuti star KIC 6382916
(J19480292+4146558), challenging the reliability of independent pulsation modes
as indicators of the star's internal structure. Through analysis of archival
data, we found distinct variations in amplitudes and frequencies of three
independent pulsation modes and their harmonics/combinations over approximately
20 days. These variations can reach amplitudes of about 140% and frequency
variations of about 12%. Correlation analysis of amplitude and frequency
variations revealed additional pulsation mode interaction details and patterns.
Notably, our findings regarding the phenomena related to harmonics of
independent pulsation modes challenge the traditional understanding in this
area. These discoveries serve as cornerstones for future research and advance
nonlinear asteroseismology.Comment: 16 pages, 10 figures, 1 tabl
Improving Scene Text Image Super-resolution via Dual Prior Modulation Network
Scene text image super-resolution (STISR) aims to simultaneously increase the
resolution and legibility of the text images, and the resulting images will
significantly affect the performance of downstream tasks. Although numerous
progress has been made, existing approaches raise two crucial issues: (1) They
neglect the global structure of the text, which bounds the semantic determinism
of the scene text. (2) The priors, e.g., text prior or stroke prior, employed
in existing works, are extracted from pre-trained text recognizers. That said,
such priors suffer from the domain gap including low resolution and blurriness
caused by poor imaging conditions, leading to incorrect guidance. Our work
addresses these gaps and proposes a plug-and-play module dubbed Dual Prior
Modulation Network (DPMN), which leverages dual image-level priors to bring
performance gain over existing approaches. Specifically, two types of
prior-guided refinement modules, each using the text mask or graphic
recognition result of the low-quality SR image from the preceding layer, are
designed to improve the structural clarity and semantic accuracy of the text,
respectively. The following attention mechanism hence modulates two
quality-enhanced images to attain a superior SR result. Extensive experiments
validate that our method improves the image quality and boosts the performance
of downstream tasks over five typical approaches on the benchmark. Substantial
visualizations and ablation studies demonstrate the advantages of the proposed
DPMN. Code is available at: https://github.com/jdfxzzy/DPMN.Comment: Accepted by AAAI-202
Anomalous pressure behavior of tangential modes in single-wall carbon nanotubes
Using the molecular dynamics simulations and the force constant model we have
studied the Raman-active tangential modes (TMs) of a (10, 0) single-wall carbon
nanotube (SWNT) under hydrostatic pressure. With increasing pressure, the
atomic motions in the three TMs present obvious diversities. The pressure
derivative of E1g, A1g, and E2g mode frequency shows an increased value (), a
constant value (), and a negative value () above 5.3 GPa, respectively. The
intrinsic characteristics of TMs consumedly help to understand the essence of
the experimental T band of CNT. The anomalous pressure behavior of the TMs
frequencies may be originated from the tube symmetry alteration from D10h to
D2h then to C2h.Comment: 15 pages, 3 pages, submitted to Phys. Rev.
4-Amino-3-(4-pyridÂyl)-1,2,4-triazole-5(4H)-thione
In the title molÂecule, C7H7N5S, the pyridyl and triazole rings form a dihedral angle of 20.07 (6)°. InterÂmolecular N—H⋯N hydrogen bonds link the molÂecules into chains extended in the direction [10]. Further stability is provided by π⋯π stacking interÂactions, indicated by short distances between the centroids of triazole rings [3.480 (5) Å] and pyridyl rings [3.574 (5) Å] of neighbouring molÂecules
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