153 research outputs found
Real-World Image Super Resolution via Unsupervised Bi-directional Cycle Domain Transfer Learning based Generative Adversarial Network
Deep Convolutional Neural Networks (DCNNs) have exhibited impressive
performance on image super-resolution tasks. However, these deep learning-based
super-resolution methods perform poorly in real-world super-resolution tasks,
where the paired high-resolution and low-resolution images are unavailable and
the low-resolution images are degraded by complicated and unknown kernels. To
break these limitations, we propose the Unsupervised Bi-directional Cycle
Domain Transfer Learning-based Generative Adversarial Network (UBCDTL-GAN),
which consists of an Unsupervised Bi-directional Cycle Domain Transfer Network
(UBCDTN) and the Semantic Encoder guided Super Resolution Network (SESRN).
First, the UBCDTN is able to produce an approximated real-like LR image through
transferring the LR image from an artificially degraded domain to the
real-world LR image domain. Second, the SESRN has the ability to super-resolve
the approximated real-like LR image to a photo-realistic HR image. Extensive
experiments on unpaired real-world image benchmark datasets demonstrate that
the proposed method achieves superior performance compared to state-of-the-art
methods.Comment: 12 pages, 5 figures,3 tables. This work is submitted to IEEE
Transactions on Systems, Man, and Cybernetics: Systems (2022). It's under
review by IEEE Transactions on Systems, Man, and Cybernetics: Systems for no
Delocalization of d-electrons induced by cation coupling in ultrathin Chevrel-phase NiMo<sub>3</sub>S<sub>4</sub> nanosheets for efficient electrochemical water splitting
Chevrel-phase metal sulfides are known to be promising materials for energy conversion and storage applications. However, a detailed understanding of the intrinsic kinetic mechanisms of electrocatalytic bifunctional hydrogen and oxygen evolution reactions (HER/OER) on NiMo3S4-based Chevrel-phases is lacking. Herein, novel ultrathin self-assembled nanosheets of NiMo3S4 are coupled with transition metal atoms (M/N-NiMo3S4; where M = Co, Fe, and Cu) were formed by a facile hydrothermal approach. Notably, the Co/N-NiMo3S4 electrocatalyst exhibits excellent performance in terms of ultralow overpotentials of 78, 208, 282, and 307 mV at 10, 100, 500, and 1000 mA cmâ2 for the HER; and 186, 204, and 225 mV at 50, 100, and 300 mA cmâ2 for the OER, respectively. Experimental and first principle calculations demonstrate that Co atoms coupling with edge Ni atoms results in dâelectron delocalization on Co/N-NiMo3S4, signifying the efficient charge transfer to improve overall water electrolysis. In addition, an upshift in the dâband center of Co/N-NiMo3S4 can optimize the free energies of a variety of reaction intermediates for water adsorption and dissociation; thereby facilitating the robust alkaline overall water electrolysis at 1.47 V. This work therefore greatly deepens the understanding of the bifunctional hydrogen and oxygen evolution reaction of Chevrel-phase electrocatalysts.</p
Delocalization of d-electrons induced by cation coupling in ultrathin Chevrel-phase NiMo<sub>3</sub>S<sub>4</sub> nanosheets for efficient electrochemical water splitting
Chevrel-phase metal sulfides are known to be promising materials for energy conversion and storage applications. However, a detailed understanding of the intrinsic kinetic mechanisms of electrocatalytic bifunctional hydrogen and oxygen evolution reactions (HER/OER) on NiMo3S4-based Chevrel-phases is lacking. Herein, novel ultrathin self-assembled nanosheets of NiMo3S4 are coupled with transition metal atoms (M/N-NiMo3S4; where M = Co, Fe, and Cu) were formed by a facile hydrothermal approach. Notably, the Co/N-NiMo3S4 electrocatalyst exhibits excellent performance in terms of ultralow overpotentials of 78, 208, 282, and 307 mV at 10, 100, 500, and 1000 mA cmâ2 for the HER; and 186, 204, and 225 mV at 50, 100, and 300 mA cmâ2 for the OER, respectively. Experimental and first principle calculations demonstrate that Co atoms coupling with edge Ni atoms results in dâelectron delocalization on Co/N-NiMo3S4, signifying the efficient charge transfer to improve overall water electrolysis. In addition, an upshift in the dâband center of Co/N-NiMo3S4 can optimize the free energies of a variety of reaction intermediates for water adsorption and dissociation; thereby facilitating the robust alkaline overall water electrolysis at 1.47 V. This work therefore greatly deepens the understanding of the bifunctional hydrogen and oxygen evolution reaction of Chevrel-phase electrocatalysts.</p
Nine-Lump Kinetic Study of Catalytic Pyrolysis of Gas Oils Derived from Canadian Synthetic Crude Oil
Catalytic pyrolysis of gas oils derived from Canadian synthetic crude oil on a kind of zeolite catalyst was conducted in a confined fluidized bed reactor for the production of light olefins. The overall reactants and products were classified into nine species, and a nine-lump kinetic model was proposed to describe the reactions based on appropriate assumptions. This kinetic model had 24 rate constants and a catalyst deactivation constant. The kinetic constants at 620°C, 640°C, 660°C, and 680°C were estimated by means of nonlinear least-square regression method. Preexponential factors and apparent activation energies were then calculated according to the Arrhenius equation. The apparent activation energies of the three feed lumps were lower than those of the intermediate product lumps. The nine-lump kinetic model showed good calculation precision and the calculated yields were close to the experimental ones
The Neighboring Component Effect in a Tristable [2]Rotaxane
The redox properties of cyclobis(paraquat-p-phenylene) cyclophane (CBPQT^(4+)) renders it a uniquely variable source of recognition in the context of mechanically interlocked molecules, through aromatic donor-acceptor interactions in its fully oxidized state (CPBQT^(4+)) and radical- pairing interactions in its partially reduced state (CBPQT^(2(â˘+))). Although it is expected that the fully reduced neutral state (CBPQT^((0))) might behave as a p-donating recognition unit, resulting in a dramatic change in its binding properties when compared with the other two redox states, its role in rotaxanes has not yet been investigated. To address this challenge, we report herein the synthesis of a tristable [2]rotaxane in which a CBPQT^(4+) ring is mechanically interlocked with a dumbbell component containing five recognition sitesâ(i) one, a bipyridinium radical cation (BIPY^((â˘+))) located centrally along the axis of the dumbbell, straddled by (ii) two tetrafluorophenylene units linked to (iii) two triazole rings. In addition to the selective recognition between (iv) the CBPQT^(4+) ring and the triazole units, and (v) the CBPQT^(2(â˘+)) ring and the reduced BIPY^((â˘+)) unit in the dumbbell component, investigations in solution have now confirmed the presence of additional noncovalent bonding interactions between the CBPQT^((0)) ring, acting as a donor in its neutral state towards the two tetrafluorophenylene acceptors in the dumbbell component. The unveiling of this piece of molecular recognition in a [2]rotaxane is reminiscent of the existence in much simpler, covalently linked, organic molecules of neighboring group participation (anchimeric assistance giving way to transannular interactions) in small-, medium-, and large-membered rings
Native Proteomics in Discovery Mode Using Size-Exclusion ChromatographyâCapillary Zone ElectrophoresisâTandem Mass Spectrometry
Native proteomics aims to characterize complex proteomes under native conditions and
ultimately produces a full picture of endogenous protein complexes in cells. It requires
novel analytical platforms for high-resolution and liquid-phase separation of protein
complexes prior to native mass spectrometry (MS) and MS/MS. In this work, size
exclusion chromatography (SEC)-capillary zone electrophoresis (CZE)-MS/MS was
developed for native proteomics in discovery mode, resulting in the identification of 144
proteins, 672 proteoforms, and 23 protein complexes from the Escherichia coli
proteome. The protein complexes include four protein homodimers, 16 protein-metal
complexes, two protein-[2Fe-2S] complexes, and one protein-glutamine complex. Half
of them have not been reported in the literature. This work represents the first example
of online liquid-phase separation-MS/MS for characterization of a complex proteome
under the native condition, offering the proteomics community an efficient and simple
platform for native proteomics
Roughage quality determines the production performance of post-weaned Hu sheep via altering ruminal fermentation, morphology, microbiota, and the global methylome landscape of the rumen wall
Roughage quality is a crucial factor influencing the growth performance and feeding cost of ruminants; however, a systematic investigation of the mechanisms underlying this is still lacking. In this study, we examined the growth performance, meat quality, ruminal fermentation parameters, rumen microbiome, and tissue methylomes of post-weaned Hu sheep fed low- or high-quality forage-based diets. Our results showed that sheep in the alfalfa hay (AG) and peanut vine (PG) groups exhibited better growth performance, slaughter performance, and meat quality than sheep in the wheat straw group (WG). The sheep in the AG possessed relatively higher contents of serum immunoglobins (IgA, IgG, and IgM) and lower contents of serum inflammation factors (TNF-ι, IL-1β, IL-6, and IL-8) than those in the WG and the PG did. In addition, the levels of blood T lymphocytes (CD4+ and CD8+) and the CD4-to-CD8 ratio were significantly higher in the AG sheep than in the WG sheep and PG sheep. The concentration of ruminal NH3-N was highest in WG sheep, whereas the concentrations of individual and total short-chain fatty acids (SCFAs) were highest in the PG sheep. The length, width, and surface area of ruminal papillae were markedly different among the three groups, with the sheep in the PG being the most morphologically developed. The main ruminal microbes at the genus level include Prevotella 1, Rikenellaceae RC9 gut group, norank f F082, Ruminococcus 1, and Ruminococcus 2. The relative abundances of certain species are positively or negatively associated with fermentation parameters and growth index. For example, the fibrolytic bacteria Ruminococcaceae UGG-001 showed positive relationships with the concentration of SCFAs, except propionate. In addition, the relative abundances of fibrolytic bacteria (e.g., Ruminoccus 1) showed a negative relationship with starch-degrading bacteria (e.g., Prevotellaceae). The genome-wide DNA methylation analysis revealed that rumen tissues in the PG sheep and WG sheep occupied different global DNA methylomes. The genes with differentially methylated promoters were involved in known pathways (e.g., the FoxO signaling pathway) and the Gene Ontology (GO) terms (e.g., anatomical structure morphogenesis) pertaining to rumen development. Two candidate genes (ACADL and ENSOARG00020014533) with hyper- and hypo-methylated promoters were screened as potential regulators of rumen development. In conclusion, roughage quality determines sheep growth performance via directly influencing rumen fermentation and microbiome composition, and indirectly affecting rumen development at the epigenetic level
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