132 research outputs found
Causality-Based Feature Importance Quantifying Methods: PN-FI, PS-FI and PNS-FI
In the current ML field models are getting larger and more complex, and data
used for model training are also getting larger in quantity and higher in
dimensions. Therefore, in order to train better models, and save training time
and computational resources, a good Feature Selection (FS) method in the
preprocessing stage is necessary. Feature importance (FI) is of great
importance since it is the basis of feature selection. Therefore, this paper
creatively introduces the calculation of PN (the probability of Necessity), PN
(the probability of Sufficiency), and PNS (the probability of Necessity and
Sufficiency) of Causality into quantifying feature importance and creates 3 new
FI measuring methods, PN-FI, which means how much importance a feature has in
image recognition tasks, PS-FI that means how much importance a feature has in
image generating tasks, and PNS-FI which measures both. The main body of this
paper is three RCTs, with whose results we show how PS-FI, PN-FI, and PNS-FI of
3 features, dog nose, dog eyes, and dog mouth are calculated. The experiments
show that firstly, FI values are intervals with tight upper and lower bounds.
Secondly, the feature dog eyes has the most importance while the other two have
almost the same. Thirdly, the bounds of PNS and PN are tighter than the bounds
of PS.Comment: 7 page
Sonochemical synthesis of palladium nanoparticles and its electrocatalytic activity for oxidation of formic acid
Monodispersed palladium nanoparticles can be synthesized by ultrasonic without gas protection and reductant in the palladium(â…ˇ) chlorid aqueous solution by the addition of a small quantity of polyvinylpyrrolidone (PVP). The monodispersity and column aspect of palladium nanoparticles were observed TEM and HRTEM respectively. The five X-ray diffraction peaks of the metallic Pd were carried out to indicate that Pd(â…ˇ) ions were reduced to palladium atoms Pd(0). The stabilization of nanoparticles had been investigated using FT-IR spectroscopy, and then the result showed the PVP can protect the metal nanoparticles via the coordination of the PVP carbonyl group to the palladium atoms and the steric effect of the PVP polymer long chain
Interactions Between Light Intensity and Phosphorus Nutrition Affect the P Uptake Capacity of Maize and Soybean Seedling in a Low Light Intensity Area
To capture more nutrients, root systems of maize (Zea mays L.) and soybean (Glycine max L.) exhibit morphological and physiological plasticity to a localized supply of phosphorus (P). However, the mechanisms of the interaction between light intensity and P affecting root morphological and physiological alterations remain unclear. In the present study, the regulation of P uptake capacity of maize and soybean by light intensity and localized P supply was investigated in a low solar radiation area. The plants were grown under continual and disrupted light conditions with homogeneous and heterogeneous P supply. Light capture of maize and soybean increased under the disrupted light condition. Plant dry weight and P uptake were increased by more light capture, particularly when plants were grown in soil with heterogeneous P supply. Similarly, both localized P supply and disrupted light treatment increased the production of fine roots and specific root length in maize. Both homogeneous P supply and disrupted light treatment increased the malate and citrate exudation in the root of soybean. Across all of the experimental treatments, high root morphological plasticity of maize and root physiological plasticity of soybean were associated with lower P concentrations in leaves and greater sucrose concentrations in roots. It is suggested that the carbon (C), exceeded shoot growth capabilities and was transferred to roots as sucrose, which may serve as both a nutritional signal and a C-substrate for root morphological and physiological changes
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TAO Conceptual Design Report: A Precision Measurement of the Reactor Antineutrino Spectrum with Sub-percent Energy Resolution
The Taishan Antineutrino Observatory (TAO, also known as JUNO-TAO) is a
satellite experiment of the Jiangmen Underground Neutrino Observatory (JUNO). A
ton-level liquid scintillator detector will be placed at about 30 m from a core
of the Taishan Nuclear Power Plant. The reactor antineutrino spectrum will be
measured with sub-percent energy resolution, to provide a reference spectrum
for future reactor neutrino experiments, and to provide a benchmark measurement
to test nuclear databases. A spherical acrylic vessel containing 2.8 ton
gadolinium-doped liquid scintillator will be viewed by 10 m^2 Silicon
Photomultipliers (SiPMs) of >50% photon detection efficiency with almost full
coverage. The photoelectron yield is about 4500 per MeV, an order higher than
any existing large-scale liquid scintillator detectors. The detector operates
at -50 degree C to lower the dark noise of SiPMs to an acceptable level. The
detector will measure about 2000 reactor antineutrinos per day, and is designed
to be well shielded from cosmogenic backgrounds and ambient radioactivities to
have about 10% background-to-signal ratio. The experiment is expected to start
operation in 2022
Detection of the Diffuse Supernova Neutrino Background with JUNO
As an underground multi-purpose neutrino detector with 20 kton liquid scintillator, Jiangmen Underground Neutrino Observatory (JUNO) is competitive with and complementary to the water-Cherenkov detectors on the search for the diffuse supernova neutrino background (DSNB). Typical supernova models predict 2-4 events per year within the optimal observation window in the JUNO detector. The dominant background is from the neutral-current (NC) interaction of atmospheric neutrinos with 12C nuclei, which surpasses the DSNB by more than one order of magnitude. We evaluated the systematic uncertainty of NC background from the spread of a variety of data-driven models and further developed a method to determine NC background within 15\% with {\it{in}} {\it{situ}} measurements after ten years of running. Besides, the NC-like backgrounds can be effectively suppressed by the intrinsic pulse-shape discrimination (PSD) capabilities of liquid scintillators. In this talk, I will present in detail the improvements on NC background uncertainty evaluation, PSD discriminator development, and finally, the potential of DSNB sensitivity in JUNO
Potential of Core-Collapse Supernova Neutrino Detection at JUNO
JUNO is an underground neutrino observatory under construction in Jiangmen, China. It uses 20kton liquid scintillator as target, which enables it to detect supernova burst neutrinos of a large statistics for the next galactic core-collapse supernova (CCSN) and also pre-supernova neutrinos from the nearby CCSN progenitors. All flavors of supernova burst neutrinos can be detected by JUNO via several interaction channels, including inverse beta decay, elastic scattering on electron and proton, interactions on C12 nuclei, etc. This retains the possibility for JUNO to reconstruct the energy spectra of supernova burst neutrinos of all flavors. The real time monitoring systems based on FPGA and DAQ are under development in JUNO, which allow prompt alert and trigger-less data acquisition of CCSN events. The alert performances of both monitoring systems have been thoroughly studied using simulations. Moreover, once a CCSN is tagged, the system can give fast characterizations, such as directionality and light curve
Real-time Monitoring for the Next Core-Collapse Supernova in JUNO
Core-collapse supernova (CCSN) is one of the most energetic astrophysical
events in the Universe. The early and prompt detection of neutrinos before
(pre-SN) and during the SN burst is a unique opportunity to realize the
multi-messenger observation of the CCSN events. In this work, we describe the
monitoring concept and present the sensitivity of the system to the pre-SN and
SN neutrinos at the Jiangmen Underground Neutrino Observatory (JUNO), which is
a 20 kton liquid scintillator detector under construction in South China. The
real-time monitoring system is designed with both the prompt monitors on the
electronic board and online monitors at the data acquisition stage, in order to
ensure both the alert speed and alert coverage of progenitor stars. By assuming
a false alert rate of 1 per year, this monitoring system can be sensitive to
the pre-SN neutrinos up to the distance of about 1.6 (0.9) kpc and SN neutrinos
up to about 370 (360) kpc for a progenitor mass of 30 for the case
of normal (inverted) mass ordering. The pointing ability of the CCSN is
evaluated by using the accumulated event anisotropy of the inverse beta decay
interactions from pre-SN or SN neutrinos, which, along with the early alert,
can play important roles for the followup multi-messenger observations of the
next Galactic or nearby extragalactic CCSN.Comment: 24 pages, 9 figure
Sonochemical synthesis of palladium nanoparticles and its electrocatalytic activity for oxidation of formic acid
330-334Monodispersed palladium nanoparticles have been synthesized from palladium(II) chloride aqueous solution by ultrasonication without gas protection and in the absence of an external reducing agent, by the addition of a small quantity of polyvinylpyrrolidone (PVP). The monodispersity and columnar crystallinity of palladium nanoparticles have been observed using TEM and HRTEM respectively. The five X-ray diffraction peaks of the metallic Pd indicated that Pd(II) ions have been reduced to palladium atoms Pd(0). The formation of nanoparticles has been investigated using FT-IR spectroscopy. Results show that the PVP can protect metal nanoparticles via the coordination of the PVP carbonyl group to the palladium atoms and the steric effect of the PVP polymer long chain. The activity towards formic acid oxidation reaction (FAOR) has also been measured
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