6,003 research outputs found
AutoDeconJ: a GPU accelerated ImageJ plugin for 3D light field deconvolution with optimal iteration numbers predicting
Light field microscopy is a compact solution to high-speed 3D fluorescence
imaging. Usually, we need to do 3D deconvolution to the captured raw data.
Although there are deep neural network methods that can accelerate the
reconstruction process, the model is not universally applicable for all system
parameters. Here, we develop AutoDeconJ, a GPU accelerated ImageJ plugin for
4.4x faster and accurate deconvolution of light field microscopy data. We
further propose an image quality metric for the deconvolution process, aiding
in automatically determining the optimal number of iterations with higher
reconstruction accuracy and fewer artifact
Magnetic and structural transitions in LaNaFeAs single crystals
LaNaFeAs single crystals have been grown out of an
NaAs flux in an alumina crucible and characterized by measuring magnetic
susceptibility, electrical resistivity, specific heat, as well as single
crystal x-ray and neutron diffraction. LaNaFeAs single
crystals show a structural phase transition from a high temperature tetragonal
phase to a low-temperature orthorhombic phase at T\,=\,125\,K. This
structural transition is accompanied by an anomaly in the temperature
dependence of electrical resistivity, anisotropic magnetic susceptibility, and
specific heat. Concomitant with the structural phase transition, the Fe moments
order along the \emph{a} direction with an ordered moment of
0.7(1)\, at \emph{T}\,=\,5 K. The low temperature stripe
antiferromagnetic structure is the same as that in other
\emph{A}FeAs (\emph{A}\,=\,Ca, Sr, Ba) compounds.
LaNaFeAs provides a new material platform for the
study of iron-based superconductors where the electron-hole asymmetry could be
studied by simply varying La/Na ratio.Comment: 9 pages, 7 figures, to appear in Physical Review
A Statistical Study on Force-Freeness of Solar Magnetic Fields in the Photosphere
It is an indisputable fact that solar magnetic fields are force-free in the
corona, where force free fields means that current and magnetic fields are
parallel and there is no Lorentz force in the fields. While the force-free
extent of photospheric magnetic fields remains open. In this paper, the
statistical results about it is given. The vector magnetograms (namely,
, and in heliocentric coordinates) are employed, which
are deduced and calibrated from Stokes spectra, observed by Solar Magnetic
Field Telescope (SMFT) at Huairou Solar Observing Station (HSOS) are used. We
study and calibrated 925 magnetograms calibrated by two sets of calibration
coefficients, that indicate the relations between magnetic fields and the
strength of Stokes spectrum and can be calculated either theoretically or
empirically. The statistical results show that the majority of active region
magnetic fields are not consistent with the force-free model.Comment: 10 pages, 5 figures, has been accepted by PAS
Effect of Relative Humidity on Mechanical Degradation of Medium Mn Steels
Medium Mn steels have been considered as the next-generation materials for use in the automotive industry due to their excellent strength and ductility balance. To reduce the total weight and improve the safety of vehicles, medium Mn steels look forward to a highly promising future. However, hydrogen-induced delayed cracking is a concern for the use of high strength steels. This work is focused on the service characteristics of two kinds of medium Mn steels under different relative humidity conditions (40%, 60%, 80% and 100%). Under normal relative humidity (about 40%) at 25 °C, the hydrogen concentration in steel is 0.4 ppm. When exposed to higher relative humidity, the hydrogen concentration in steel increases slowly and reaches a stable value, about 0.8 ppm. In slow strain rate tensile tests under different relative humidity conditions, the tensile strength changed, the hydrogen concentration increased and the elongation decreased as well, thereby increasing the hydrogen embrittlement sensitivity. In other words, the smaller the tensile rate applied, the greater the hydrogen embrittlement sensitivity. In constant load tests under different relative humidity conditions, the threshold value of the delayed cracking of M7B (‘M’ referring to Mn, ‘7’ meaning the content of Mn, ‘B’ denoting batch annealing) steel maintains a steady value of 0.82 σb (tensile strength). The threshold value of the delayed cracking of M10B significantly changed along with relative humidity. When relative humidity increased from 60% to 80%, the threshold dropped sharply from 0.63 σb to 0.52 σb. We define 80% relative humidity as the ‘threshold humidity’ for M10B
Solution-Processed Epitaxial Growth of Arbitrary Surface Nanopatterns on Hybrid Perovskite Monocrystalline Thin Films.
Semiconductor surface patterning at the nanometer scale is crucial for high-performance optical, electronic, and photovoltaic devices. To date, surface nanostructures on organic-inorganic single-crystal perovskites have been achieved mainly through destructive methods such as electron-beam lithography and focused ion beam milling. Here, we present a solution-based epitaxial growth method for creating nanopatterns on the surface of perovskite monocrystalline thin films. We show that high-quality monocrystalline arbitrary nanopatterns can form in solution with a low-cost simple setup. We also demonstrate controllable photoluminescence from nanopatterned perovskite surfaces by adjusting the nanopattern parameters. A seven-fold enhancement in photoluminescence intensity and a three-time reduction of the surface radiative recombination lifetime are observed at room temperature for nanopatterned MAPbBr3 monocrystalline thin films. Our findings are promising for the cost-effective fabrication of monocrystalline perovskite on-chip electronic and photonic circuits down to the nanometer scale with finely tunable optoelectronic properties
Ca/Al of plagioclase-hosted melt inclusions as an indicator for post-entrapment processes at mid-ocean ridges?
The composition of melt inclusions in basalts erupted at mid-ocean ridges may be modified by post-entrapment processes, so the present composition of melt inclusions may not represent their original composition at the time of entrapment. By combining the melt inclusion composition in samples from the South Mid-Atlantic Ridge at 19ºS analyzed in this study, and from the Petrological Database, we found that post-entrapment crystallization processes resulted in higher Ca/Al, Mg#[100°—atomic Mg2+/(Mg2++Fe2+)], MgO and FeO contents, and lower CaO and Al2O3 contents of plagioclase-hosted melt inclusions relative to those hosted in olivine. In addition, melt inclusions hosted in plagioclase with anorthite content larger than 80mol.% had been modified more readily than others. By discussing the relationships between Ca/Al and fractional crystallization, post-entrapment crystallization, and the original melt composition, we propose that Ca/Al can be regarded as an indicator of the effect of post-entrapment processes on melt inclusion composition. Specifically, i) when Ca/Al<0.78, melt inclusion compositions corrected for fractional crystallization to Mg#=72 can represent the primary magma at mid-ocean ridges; ii) when 0.78<Ca/Al<1.0, melt inclusions are mainly modified by post-entrapment crystallization effects, and can reveal the original melt composition after correcting for these effects; iii) when Ca/Al>1.0, the compositions of melt inclusions do not reflect the original melt composition nor preserve information about the mantle source. According to these criteria, plagioclase-hosted melt inclusions with Ca/Al>1.0 in basalts from the South Mid-Atlantic Ridge at 19ºS cannot represent the composition of the melt at the moment of their entrapment
Ca/Al of plagioclase-hosted melt inclusions as an indicator for post-entrapment processes at mid-ocean ridges?
The composition of melt inclusions in basalts erupted at mid-ocean ridges may be modified by post-entrapment processes, so the present composition of melt inclusions may not represent their original composition at the time of entrapment. By combining the melt inclusion composition in samples from the South Mid-Atlantic Ridge at 19ºS analyzed in this study, and from the Petrological Database, we found that post-entrapment crystallization processes resulted in higher Ca/Al, Mg#[100°-atomic Mg2+/(Mg2++Fe2+)], MgO and FeO contents, and lower CaO and Al2O3 contents of plagioclase-hosted melt inclusions relative to those hosted in olivine. In addition, melt inclusions hosted in plagioclase with anorthite content larger than 80mol.% had been modified more readily than others. By discussing the relationships between Ca/Al and fractional crystallization, post-entrapment crystallization, and the original melt composition, we propose that Ca/Al can be regarded as an indicator of the effect of post-entrapment processes on melt inclusion composition. Specifically, i) when Ca/Al1.0, the compositions of melt inclusions do not reflect the original melt composition nor preserve information about the mantle source. According to these criteria, plagioclase-hosted melt inclusions with Ca/Al>1.0 in basalts from the South Mid-Atlantic Ridge at 19ºS cannot represent the composition of the melt at the moment of their entrapment
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