88 research outputs found
Image Super-resolution with An Enhanced Group Convolutional Neural Network
CNNs with strong learning abilities are widely chosen to resolve
super-resolution problem. However, CNNs depend on deeper network architectures
to improve performance of image super-resolution, which may increase
computational cost in general. In this paper, we present an enhanced
super-resolution group CNN (ESRGCNN) with a shallow architecture by fully
fusing deep and wide channel features to extract more accurate low-frequency
information in terms of correlations of different channels in single image
super-resolution (SISR). Also, a signal enhancement operation in the ESRGCNN is
useful to inherit more long-distance contextual information for resolving
long-term dependency. An adaptive up-sampling operation is gathered into a CNN
to obtain an image super-resolution model with low-resolution images of
different sizes. Extensive experiments report that our ESRGCNN surpasses the
state-of-the-arts in terms of SISR performance, complexity, execution speed,
image quality evaluation and visual effect in SISR. Code is found at
https://github.com/hellloxiaotian/ESRGCNN
Real-space Observation of Unidirectional Charge Density Wave and Complex Structural Modulation in the Pnictide Superconductor BaSrNiAs
Here we use low-temperature and variable-temperature scanning tunneling
microscopy to study the pnictide superconductor, BaSrNiAs.
In the low-temperature phase (triclinic phase) of BaNiAs, we observe
the unidirectional charge density wave (CDW) with = 1/3 on both the Ba and
NiAs surfaces. On the NiAs surface of the triclinic BaNiAs, there are
structural-modulation-induced chain-like superstructures with distinct
periodicities. In the high-temperature phase (tetragonal phase) of
BaNiAs, the NiAs surface appears as the periodic 1 by 2 superstructure.
Interestingly, in the triclinic phase of BaSrNiAs, the
unidirectional CDW is suppressed on both the Ba/Sr and NiAs surfaces, and the
Sr substitution stabilizes the periodic 1 by 2 superstructure on the NiAs
surface, which enhance the superconductivity in
BaSrNiAs. Our results provide important microscopic
insights for the interplay among the unidirectional CDW, structural modulation,
and superconductivity in this class of pnictide superconductors.Comment: 15 pages, 4 figure
Ti4O7/g-C3N4 for Visible Light Photocatalytic Oxidation of Hypophosphite: Effect of Mass Ratio of Ti4O7/g-C3N4
Hypophosphite wastewater treatment is still a critical issue in metallurgical processes and the oxidation of hypophosphite to phosphate followed by the precipitation of phosphate is an important strategy for hypophosphite wastewater treatment. Herein, Ti4O7/g-C3N4 photocatalysts with various mass ratios (Ti4O7 (m): g-C3N4 (m) = 0.5, 0.2, 0.1, and 0.05) were synthesized by a hydrolysis method and the effect of the mass ratio of Ti4O7 (m): g-C3N4 (m) on Ti4O7/g-C3N4 visible light photocatalytic oxidation of hypophosphite was evaluated. The as-prepared Ti4O7/g-C3N4 were characterized and confirmed by SEM, XPS, XRD and FTIR. Moreover, the specific surface area and the distribution of pore size of Ti4O7/g-C3N4 was also analyzed. Our results showed that Ti4O7/g-C3N4 exhibited remarkably improved photocatalytic performance on hypophosphite oxidation compared with g-C3N4 and meanwhile 1:2-Ti4O7/g-C3N4 with a mass ratio of 0.5 showed the best photocatalytic performance with the highest oxidation rate constant (17.7-fold and 91.0-fold higher than that of pure g-C3N4 and Ti4O7, respectively). The enhanced performance of photocatalytic oxidation of hypophosphite was ascribed to the heterojunction structure of Ti4O7/g-C3N4 with broader light absorption and significantly enhanced efficiency of the charge carrier (e−-h+) generation and separation. Additionally, the generated ·OH and ·O2- radicals contributed to the hypophosphite oxidation during the photocatalytic system
A Fully Data-Driven Approach for Realistic Traffic Signal Control Using Offline Reinforcement Learning
The optimization of traffic signal control (TSC) is critical for an efficient
transportation system. In recent years, reinforcement learning (RL) techniques
have emerged as a popular approach for TSC and show promising results for
highly adaptive control. However, existing RL-based methods suffer from notably
poor real-world applicability and hardly have any successful deployments. The
reasons for such failures are mostly due to the reliance on over-idealized
traffic simulators for policy optimization, as well as using unrealistic
fine-grained state observations and reward signals that are not directly
obtainable from real-world sensors. In this paper, we propose a fully
Data-Driven and simulator-free framework for realistic Traffic Signal Control
(D2TSC). Specifically, we combine well-established traffic flow theory with
machine learning to construct a reward inference model to infer the reward
signals from coarse-grained traffic data. With the inferred rewards, we further
propose a sample-efficient offline RL method to enable direct signal control
policy learning from historical offline datasets of real-world intersections.
To evaluate our approach, we collect historical traffic data from a real-world
intersection, and develop a highly customized simulation environment that
strictly follows real data characteristics. We demonstrate through extensive
experiments that our approach achieves superior performance over conventional
and offline RL baselines, and also enjoys much better real-world applicability.Comment: 15 pages, 6 figure
Corrigendum: Ti4O7/g-C3N4 visible light photocatalytic performance on hypophosphite oxidation: Effect of annealing temperature
Probing hidden Mott gap and incommensurate charge modulation on the polar surfaces of PdCrO
Here we report a combined study of low-temperature scanning tunneling
microscopy (STM) and dynamical mean-field theory (DMFT) on PdCrO, a
delafossite metal with an antiferromagnetic order below ~37.5 K. First, on the
CrO-terminated polar surface we detect a gap-like feature both below and
above the N\'eel temperature. The DMFT calculations indicate that this gap is
opened due to the strong correlations of Cr-3d electrons, suggesting the hidden
Mott nature of the gap. Then, we observe two kinds of Pd-terminated polar
surfaces. One is a well-ordered Pd surface with the
Fermi-surface-nesting-induced incommensurate charge modulation, while the other
one is a reconstructed Pd surface with the individual nano-scale non-periodic
domain structures. On the well-ordered Pd surface, the interference between the
incommensurate charge modulation and the atomic lattice forms the periodic
moir\'e pattern. Our results provide important microscopic information for
fully understanding the correlated electronic properties of this class of
materials.Comment: 11 pages, 4 figure
Sources and distribution of particulate organic carbon in Great Wall Cove and Ardley Cove, King George Island, West Antarctica
Concentrations of chlorophyll-a (Chl-a), particulate organic carbon (POC) and its stable carbon isotope composition (δ13C) were analyzed to investigate the biogeochemical characteristics and sources of POC in Great Wall Cove (GWC) and Ardley Cove (AC) during the austral summer. POC concentrations ranged from 50.51 to 115.41 μg·L−1 (mean±1 standard deviation: 77.69±17.27 μg·L−1) in GWC and from 63.42 to 101.79 μg·L−1 (82.67±11.83 μg·L−1) in AC. The POC δ13C ranged from −30.83‰ to −26.12‰ (−27.40‰±0.96‰) in GWC and from −28.21‰ to −26.65‰ (−27.45‰±0.47‰) in AC. The temperature and salinity results showed distinct runoff signals in both GWC and AC, although the δ13C data and POC distribution indicate a negligible influence of land sources upon POC. The δ13C values suggest that POC is of predominantly marine origin. The POC/Chl-a ratio and the relationship between POC and Chl-a indicate that phytoplankton, organic detritus and heterotrophic organisms are significant contributors to POC in GWC and AC
Seawater nutrient and chlorophyll α distributions near the Great Wall Station, Antarctica
We examined the influences upon nutrient, temperature, salinity and chlorophyll a distributions in Great Wall Cove (GWC) and Ardley Cove (AC), near the Chinese Antarctic Great Wall Station, using measurements taken in January 2013 and other recent data. Nutrient concentrations were high, with phosphate concentrations of 1.94 (GWC) and 1.96 (AC) μmol·L−1, DIN(dissolved inorganic nitrogen) concentrations of 26.36 (GWC) and 25.94 (AC) μmol·L−1 and silicate concentrations of 78.6 (GWC) and 79.3 (AC) μmol·L−1. However, average concentrations of chlorophyll a were low (1.29 μg·L−1, GWC and 1.08 μg·L−1, AC), indicating that this region is a high-nutrient and low-chlorophyll (HNLC) area. Nutrient concentrations of freshwater (stream and snowmelt) discharge into GWC and AC in the austral summer are low, meaning freshwater discharge dilutes the nutrient concentrations in the two coves. Strong intrusion of nutrient-rich water from the Bransfield Current in the south was the main source of nutrients in GWC and AC. Low water temperature and strong wind-induced turbulence and instability in the upper layers of the water column were the two main factors that caused the low phytoplankton biomass during the austral summer
Identification of QTNs Controlling Seed Protein Content in Soybean Using Multi-Locus Genome-Wide Association Studies
Protein content (PC), an important trait in soybean (Glycine max) breeding, is controlled by multiple genes with relatively small effects. To identify the quantitative trait nucleotides (QTNs) controlling PC, we conducted a multi-locus genome-wide association study (GWAS) for PC in 144 four-way recombinant inbred lines (FW-RILs). All the FW-RILs were phenotyped for PC in 20 environments, including four locations over 4 years with different experimental treatments. Meanwhile, all the FW-RILs were genotyped using SoySNP660k BeadChip, producing genotype data for 109,676 non-redundant single-nucleotide polymorphisms. A total of 129 significant QTNs were identified by five multi-locus GWAS methods. Based on the 22 common QTNs detected by multiple GWAS methods or in multiple environments, pathway analysis identified 8 potential candidate genes that are likely to be involved in protein synthesis and metabolism in soybean seeds. Using superior allele information for 22 common QTNs in 22 elite and 7 inferior lines, we found higher superior allele percentages in the elite lines and lower percentages in the inferior lines. These findings will contribute to the discovery of the polygenic networks controlling PC in soybean, increase our understanding of the genetic foundation and regulation of PC, and be useful for molecular breeding of high-protein soybean varieties
The Internal Recycle Reactor Enhances Porous Calcium Silicate Hydrates to Recover Phosphorus from Aqueous Solutions
In this experiment, the porous calcium silicate hydrates (P-CSHs) were prepared via a hydrothermal method and then modified by polyethylene glycol (PEG). The modified P-CSHs combined with an internal recycle reactor could successfully recover the phosphorus from electroplating wastewater. The modified P-CSHs were characterized by X-ray diffraction (XRD), N2 adsorption-desorption isotherms, and Fourier transform infrared spectroscopy (FT-IR). After compared with different samples, the modified P-CSHs-PEG2000 sample had larger specific surface area of 87.48 m2/g and higher pore volume of 0.33 cm3/g, indicating a high capacity for phosphorus recovery. In the process of phosphorus recovery, the pH value of solution was increased to 9.5, which would enhance the recovery efficiency of phosphorus. The dissolution rate of Ca2+ from P-CSH-PEG2000 was fast, which was favorable for phosphorus precipitation and phosphorus recovery. The effects of initial concentration of phosphorus, P-CSHs-PEG2000 dosage, and stirring speed on phosphorus recovery were analyzed, so the optimal operation conditions for phosphorus recovery were obtained. The deposition was analyzed by XRD, N2 adsorption-desorption, and SEM techniques; it was indicated that the pore volume and surface area of the P-CSHs-PEG2000 were significantly reduced, and the deposition on the surface of P-CSHs-PEG2000 was hydroxyapatite
- …