Dense depth cues are important and have wide applications in various computer vision tasks. In autonomous driving, LIDAR sensors are adopted to acquire depth measurements around the vehicle to ...perceive the surrounding environments. However, depth maps obtained by LIDAR are generally sparse because of its hardware limitation. The task of depth completion attracts increasing attention, which aims at generating a dense depth map from an input sparse depth map. To effectively utilize multi-scale features, we propose three novel sparsity-invariant operations, based on which, a sparsity-invariant multi-scale encoder-decoder network (HMS-Net) for handling sparse inputs and sparse feature maps is also proposed. Additional RGB features could be incorporated to further improve the depth completion performance. Our extensive experiments and component analysis on two public benchmarks, KITTI depth completion benchmark and NYU-depth-v2 dataset, demonstrate the effectiveness of the proposed approach. As of Aug. 12th, 2018, on KITTI depth completion leaderboard, our proposed model without RGB guidance ranks 1st among all peer-reviewed methods without using RGB information, and our model with RGB guidance ranks 2nd among all RGB-guided methods.
Ni2P/Cd0.5Zn0.5S showed higher activity than pure Cd0.5Zn0.5S for photocatalytic N2 fixation without any scavengers under visible light irradiation (λ>400nm), and the concentration of NH3 reached to ...101.5μmolL−1 with quantum efficiency of 4.32% at 420nm. Display omitted
•Ni2P/Cd0.5Zn0.5S was synthesized and characterized.•Ni2P/Cd0.5Zn0.5S had higher activity than Cd0.5Zn0.5S for photocatalytic N2 fixation.•TMP improved the photo-induced carrier separation efficiency ofCd0.5Zn0.5S.
In this paper, transition metal phosphide (TMP) was used as cocatalyst to enhance the photocatalytic activity of Cd0.5Zn0.5S solid solution for nitrogen fixation under visible light irradiation. The Ni2P/Cd0.5Zn0.5S photocatalyst was characterized by X-ray diffraction patterns (XRD), transmission electron microscopy (TEM), UV–vis diffuse reflectance spectra (DRS) and X-ray photoelectron spectroscopy (XPS). The photocatalytic data showed that Ni2P/Cd0.5Zn0.5S had higher activity than pure Cd0.5Zn0.5S for photocatalytic dinitrogen (N2) fixation in the absence of any scavengers. After 1h visible light irradiation (λ>400nm), the concentration of NH3 reached to 101.5μmolL−1. And the quantum efficiency at 420nm monochromatic light reached 4.32%, which much higher than other semiconductors. Time-resolved PL spectra, photocurrent and electrochemical impedance (EIS) spectroscopy revealed that higher photo-induced carrier separation efficiency of Ni2P/Cd0.5Zn0.5S. This work introduced Cd0.5Zn0.5S solid solution photocatalyst to reduce nitrogen, and offered a greenly, economically and efficiently way for nitrogen fixation.
Sequence-defined polymers have garnered increasing attention in a broad range of applications from materials engineering to medical science. Reversible addition-fragmentation chain transfer single ...unit monomer insertion (RAFT SUMI) technology has recently emerged as a powerful tool for sequence-defined polymer synthesis, which utilizes sequential monomer radical additions occurring one unit at a time to assemble olefins into uniform polymers. The strategy of employing alternating additions of electron-donor and acceptor (D-A) monomers can be used to prepare long chain sequence-defined polymers by the RAFT SUMI technique. However, considering both terminal and penultimate unit effects, complex radical reaction kinetics can result from various monomer addition orders particularly if three or more different families of vinyl monomers are used to build diverse sequences. Simplifying reaction processes and establishing reaction kinetics will be critical for effective synthesis of sequence-defined polymers. Herein, a series of model trimers containing D-A-D and A-D-A triads was thus produced from four families of α,β-disubstituted vinyl monomers (
N
-phenylmaleimide, fumaronitrile and dimethyl fumarate and indene). Such trimers presented distinct synthesis kinetics (reaction rate and yield). These model trimers and their kinetics data are able to provide full guidance for the synthesis of long chain discrete polymers using sequential and alternating RAFT SUMI processes.
A complete set of model trimers and their synthetic kinetics are established to guide the synthesis of diverse sequence-defined polymers.
•SOC bioavailability significantly differed among soil particle-size fractions.•SOC bioavailability of fine sand increased by 200 %, whereas clay reduced by 60 %•The porosity of fine sand was 60% of ...clay.•Abundances of soil elements of clay were 6–30 times higher than fine sand.•Microbial activity, mediated by soil morphology, affected SOC bioavailability.
Despite the fact that physical and chemical processes have been widely proposed to explicate the stabilization mechanisms of soil organic carbon (SOC), thebioavailability of SOC linked to soil physical structure, microbial community structure, and functional genes remains poorly understood. This study aims to investigate the SOC division based on bioavailability differences formed by physical isolation, and to clarify the relationships of SOC bioavailability with soil elements, pore characteristics, and microbial activity. Results revealed that soil element abundances such as SOC, TN, and DOC ranked in the same order as the soil porosity as clay > silt ≥ coarse sand > fine sand in both top and sub soil. In contrast to silt and clay, which had reduced SOC bioavailability, fine sand and coarse sand had dramatically enhanced SOC bioavailability compared to the bulk soil. The bacterial and fungal community structure was significantly influenced by particle size, porosity, and soil elements. Copiotrophic bacteria and functional genes were more prevalent in fine sand than clay, which also contained more oligotrophic bacteria. The SOC bioavailability was positively correlated with abundances of functional genes, C degradation genes, and copiotrophic bacteria, but negatively correlated with abundances of soil elements, porosity, oligotrophic bacteria, and microbial biomass (p < 0.05). This indicated that the soil physical structure divided SOC into pools with varying levels of bioavailability, with sand fractions having more bioavailable organic carbon than finer fractions. Copiotrophic Proteobacteria and oligotrophic Acidobacteria, Firmicutes, and Gemmatimonadetes made up the majority of the bacteria linked to SOC mineralization. Additionally, the fungi Mortierellomycota and Mucoromycota, which are mostly involved in SOC mineralization, may have the potential for oligotrophic metabolism. Our results indicated that particle-size fractionation could influence the SOC bioavailability by restricting SOC accessibility and microbial activity, thus having a significant impact on sustaining soil organic carbon reserves in temperate agricultural ecosystems, and provided a new research direction for organic carbon stability.
The reversible addition-fragmentation chain transfer (RAFT) agent plays a key role of "photo-iniferter" that is responsible for photo-initiation, chain transfer and termination in most photo-RAFT ...polymerization systems. With the merging of a visible light initiation method, photo-RAFT polymerization has achieved significant progress in the last decade. However, kinetic analysis is still less explored due to its inherent complexity in RAFT processes and photochemistry. Encouraged by previous works on thermally initiated RAFT polymerization, we herein investigate the kinetics of the early stage of the photo-RAFT process that comprises photo-activation of the initial RAFT agents and addition of RAFT leaving group radicals to the monomers. Apart from the complex kinetics, these reactions are generally too fast to investigate in RAFT polymerization. We employ the single unit monomer insertion (SUMI) technique to simplify and slow down these processes, in which chain propagation is absent. An in-depth look at the kinetics of the initiation process and establishment of kinetic models is thus possible. To this end, three model RAFT agents with the same terminal units and different penultimate units were synthesized and used as photo-iniferters for further single monomer additions. The effect of the penultimate units on the consumption rates of these RAFT agents has been demonstrated to be significant. A kinetic model accounting for various rate coefficients was developed to analyze the distinct rates of RAFT agent consumption. The kinetic rate equation reveals that the apparent RAFT consumption rate coefficient is positively correlated to the rate coefficients of photo-dissociation of the RAFT agents (
k
d
) and radical-monomer addition (
k
p
). Density functional theory calculation was performed to study the photo-activation and radical-monomer addition steps, implying that the reaction energies of these two steps are highly influenced by the penultimate units but in the opposite ways. For the contribution to overall RAFT agent consumption rates, the monomer addition is dominant.
The single unit monomer insertion technique provides a simple platform for the kinetic investigation of early stage of photo-RAFT process that comprises photo-activation of initial RAFT agents and addition of RAFT leaving radicals to the monomers.
Iron-cobalt (FeCo) oxides dispersed on reduced graphene oxide (rGO) were synthesized from nitrate precursors at loading levels from 10 wt% to 60 wt%. These catalysts were tested in lab-scale zinc-air ...batteries (ZABs) at a high current density of 100 mA cm
−2
of the cathode area for the first time, cycling between 60 min of discharging and 60 min of charging. The optimum loading level for the best ZAB cycling performance was found to be 40 wt%, at which CoFe
2
O
4
and CoO nanocrystals were detected. A discharge capacity of at least 90% was maintained for about 60 cycles with FeCo 40 wt%, demonstrating superior stability over amorphous FeCo oxides with FeCo 10 wt% despite similar performance at electrochemical tests. At a high current density of 100 mA cm
−2
, OER catalytic activity was found to be the limiting factor in ZAB's cyclability. The discrepancies between the ORR/OER catalytic activities by electrochemical and battery cycling test results highlight the role and importance of rGO in improving electrical conductivity and activation of metal oxide electrocatalysts under high current density conditions. The difference of battery cycling test results from traditional electrochemical test results suggests that electrochemical tests conducted at low current densities may be inadequate in predicting practical battery cycling performance.
Iron-cobalt (FeCo) oxides dispersed on reduced graphene oxide (rGO) were synthesized from nitrate precursors at loading levels from 10 wt% to 60 wt%.
Natural biopolymers, such as DNA and proteins, have uniform microstructures with defined molecular weight, precise monomer sequence, and stereoregularity along the polymer main chain that affords ...them unique biological functions. To reproduce such structurally perfect polymers and understand the mechanism of specific functions through chemical approaches, researchers have proposed using synthetic polymers as an alternative due to their broad chemical diversity and relatively simple manipulation. Herein, we report a new methodology to prepare sequence-controlled and stereospecific oligomers using alternating radical chain growth and sequential photoinduced RAFT single unit monomer insertion (photo-RAFT SUMI). Two families of cyclic monomers, the indenes and the N-substituted maleimides, can be alternatively inserted into RAFT agents, one unit at a time, allowing the monomer sequence to be controlled through sequential and alternating monomer addition. Importantly, the stereochemistry of cyclic monomer insertion into the RAFT agents is found to be trans-selective along the main chains due to steric hindrance from the repeating monomer units. All investigated cyclic monomers provide such trans-selectivity, but analogous acyclic monomers give a mixed cis- and trans-insertion.
In this communication, we report a catalyst-free methodology for single unit monomer insertion (SUMI) into reversible addition–fragmentation chain transfer (RAFT) agents initiated by low intensity ...visible light. This method is applicable to broad range of monomer families (monosubstituted vinyl monomers) and allows for the preparation of the corresponding single monomer insertion product in high yields (typically >90%; isolated yields after chromatography 60–80%). The fidelity of the end-functional SUMI products is demonstrated with use of the SUMI products in RAFT polymerization and by using the tools of conventional chemistry (thiol–ene and esterification reactions). A uniform oligomer comprising five discrete vinyl monomer repeat units was synthesized by an iterative strategy comprising three consecutive SUMI reactions and two intermediate esterification and thiol–ene steps. We thus demonstrate a new protocol for incorporating the rich functionality of available vinyl monomers into polymers where sequence is precisely defined at the monomer level.
Silver-based hybrid nanomaterials are receiving increasing attention as potential alternatives for traditional antimicrobial agents. Here, we proposed a simple and eco-friendly strategy to ...efficiently assemble zinc oxide nanoparticles (ZnO) and silver nanoparticles (AgNPs) on sericin-agarose composite film to impart superior antimicrobial activity. Based on a layer-by-layer self-assembly strategy, AgNPs and ZnO were immobilized on sericin-agarose films using the adhesion property of polydopamine. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray powder diffraction spectroscopy were used to show the morphology of AgNPs and ZnO on the surface of the composite film and analyze the composition and structure of AgNPs and ZnO, respectively. Water contact angle, swelling ratio, and mechanical property were determined to characterize the hydrophilicity, water absorption ability, and mechanical properties of the composite films. In addition, the antibacterial activity of the composite film was evaluated against Gram-positive and Gram-negative bacteria. The results showed that the composite film not only has desirable hydrophilicity, high water absorption ability, and favorable mechanical properties but also exhibits excellent antimicrobial activity against both Gram-positive and Gram-negative bacteria. It has shown great potential as a novel antimicrobial biomaterial for wound dressing, artificial skin, and tissue engineering.
ObjectivesTo synthesise current evidence from systematic reviews (SRs) regarding the efficacy and safety of non-pharmacological interventions to prevent and treat pain in newborn ...infants.DesignOverview of SRs.Data sourcesWe searched PubMed, Embase, Cochrane Library, Web of Science, CINAHL, Chinese National Knowledge Infrastructure (CNKI), Chinese Biomedical Literature Database (CBM), Wanfang Database, Chinese Science and Technology Periodical Database (VIP) and Google Scholar to identify all relevant SRs published in the last 5 years.Eligibility criteria for selecting studiesWe included SRs that evaluated the efficacy and safety of non-pharmacological interventions for neonatal pain.Data extraction and synthesisTwo reviewers independently extracted the data, assessed the methodological quality using a Measurement Tool to Assess Systematic Reviews (AMSTAR) 2 and graded the evidence quality with the Grading of Recommendations Assessment, Development and Evaluation (GRADE).ResultsA total of 29 SRs were included in this overview, of which 28 focused on procedural pain and only 1 focused on postoperative pain. Based on AMSTAR 2, seven reviews were found to be of ‘high quality‘, eight of ‘moderate quality’, five of ‘low quality’ and nine of ‘critically low quality’. The GRADE results suggested that facilitated tucking, kangaroo care, sweet solutions, familiar odour or combined non-pharmacological interventions, such as a combination of sucrose and non-nutritive sucking, were effective and safe in reducing pain from medical procedures in neonates. However, sucrose alone was less effective than local anaesthesia or a combination of the two during circumcision.ConclusionsFacilitated tucking, small volumes of sweet solutions, kangaroo care and familiar odour were recommended. Scientific implementation strategies should be developed to promote the clinical use of these effective non-pharmacological interventions. Meanwhile, further rigorous trials and SRs are needed to identify the best non-pharmacological approaches for pain from common surgery and illnesses in neonates.PROSPERO registration numberCRD42021292583.
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