Contemporary synthetic aperture radar (SAR) image processing techniques face various challenges, particularly in ship detection, background noise reduction, and information preservation. To address ...these issues, this paper introduces a novel model we called SAR-ShipSwin, which combines the swin transformer and feature pyramid network as the backbone network structure, specifically designed for ship detection in SAR images. The backbone network optimizes computational efficiency and handles occlusion and overlap issues in SAR images successfully by introducing the improved window multi-head self-attention module. To further enhance recognition accuracy, we design the background modeling network, which efficiently identifies and eliminates complex background features. Additionally, we introduce the spatial intensity geometric pooling technique, a novel pooling strategy that preserves geometric and structural information of the original region of interest, significantly reducing information loss and distortion. Considering the diverse ship shapes in SAR images, we specially design the dynamic ship shape adaptive convolution module, which dynamically adjusts the shape of convolution kernels to better match the targets. The proposed model is validated on the SSDD and HRSID datasets, achieving state-of-the-art performance.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Hydride ions (H
−
) have an appropriate size for fast transport, which makes the conduction of H
−
attractive. In this work, the H
−
transport properties of BaH
2
have been investigated under ...pressure using
in situ
impedance spectroscopy measurements up to 11.2 GPa and density functional theoretical calculations. The H
−
transport properties, including ionic migration resistance, relaxation frequency, and relative permittivity, change significantly with pressure around 2.3 GPa, which can be attributed to the structural phase transition of BaH
2
. The ionic migration barrier energy of the
P
6
3
/
mmc
phase decreases with pressure, which is responsible for the increased ionic conductivity. A huge dielectric constant at low frequencies is observed, which is related to the polarization of the H
−
dipoles. The current study establishes general guidelines for developing high-energy storage and conversion devices based on hydride ion transportation.
Compression hinders H
−
migration in the
Pnma
phase, but it makes H
−
migration easier in the
P
6
3
/
mmc
phase of BaH
2
.
An unexpected superconductivity enhancement is reported in decompressed In2Se3. The onset of superconductivity in In2Se3 occurs at 41.3 GPa with a critical temperature (Tc) of 3.7 K, peaking at 47.1 ...GPa. The striking observation shows that this layered chalcogenide remains superconducting in decompression down to 10.7 GPa. More surprisingly, the highest Tc that occurs at lower decompression pressures is 8.2 K, a twofold increase in the same crystal structure as in compression. It is found that the evolution of Tc is driven by the pressure‐induced R‐3m to I‐43d structural transition and significant softening of phonons and gentle variation of carrier concentration combined in the pressure quench. The novel decompression‐induced superconductivity enhancement implies that it is possible to maintain pressure‐induced superconductivity at lower or even ambient pressures with better superconducting performance.
Superconductivity enhancement in pressure quenching is observed in the layered material In2Se3. In situ high‐pressure resistance and magnetic measurements reveal a twofold increase of Tc at lower decompression pressure. It is found that the superconductivity enhancement in decompressed In2Se3 is driven by the significant softening of phonons and gentle variation of carrier concentration combined in the pressure quench.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
In this paper, a new method for in situ thermal conductivity measurements were established in diamond anvil cells (DAC) and achieve measurements at high pressure and high temperature under steady ...heat flow conditions. In this method, the traditional heat flux calibration was replaced by temperature measurement of anvils and finite element analysis. Furthermore, a DAC set-up with two heating furnaces was developed to better serve the proposed method. The thermal conductivity of four diamond anvils with different nitrogen content was measured and compared to reference to verify the method's feasibility and serve as calibration for future measurements.
The ionic transport properties of bismuth oxide (Bi2O3) were investigated under high pressures with impedance spectrum and Raman spectrum measurements. It was found that Bi2O3 is a pure ionic ...conductor below 9.0 GPa. Its pressure-dependent ionic conduction is determined by the diffusion rate of O2− ions. Above 9.0 GPa, the number of O2− ions that participate in electrical transportation are reduced rapidly by the pressure-induced distortion of crystal lattice, which becomes the essential factor to affect the ionic conduction. Most importantly, electronic conduction began to appear in the transportation process and coexist with the ionic conduction at 9.0 GPa indicating a few of originally localized electrons are involved in the electrical transportation due to the enhancement in distorted intension of Bi polyhedrons. Meanwhile, from the impedance spectra studies, it was also known that the electrical transport behaviors of Bi2O3 can be tuned by the frequency of input signals. At high frequencies, Bi2O3 behaves like an ionic solid electrolyte, but at low frequencies, it behaves like an electronic resistor.
The phase diagram of water near the ice VI-ice VII-liquid triple point and electrical transport properties of these ices have been studied by
in situ
electrical conductivity measurements in a diamond ...anvil cell. The obtained phase boundary between ices VI and VII and the melting curve for these ices are in accord with most previous results. The different properties and amount of orientational defects in ice VI and ice VII are associated with abrupt changes in conductivity when a phase transition from ice VI to ice VII occurs. The electrical transport mechanisms of these two ice polymorphs can be understood in terms of the conduction of the already existing ions and Bjerrum defects.
The phase boundary between ices VI and VII and melting curves for these ices were determined by measuring electrical conductivity with a diamond anvil cell.
An alternate current impedance spectrum was utilized to differentiate the electrical transport process, respectively, in the bulk and the grain boundary of barium tungstate microcrystallines under ...high pressures up to 20 GPa. For powdered BaWO4 microcrystallines, the grain boundary makes a more remarkable contribution than the bulk to the total resistance. The discontinuities of bulk resistance and relaxation frequency at about 7 and 14 GPa reflect the pressure-induced structural phase transitions of BaWO4 from scheelite to fergusonite structure and from fergusonite to an unknown disordered structure, respectively. The activation energy of the grain boundary decreases with increasing pressure from 6.9 to 8.9 GPa, indicating that the compression has a negative contribution to the activation energy and the transport of charge carriers through the boundary becomes easier. The activation energy of the bulk also shows a similar phenomenon. In addition, the ascending relaxation frequency of the bulk and grain boundary shows that the polarization process needs much shorter time in the state of three-phase coexistence.
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