Spatial-temporal motion information integration for action detection and recognition in non-static background

Various motion detection methods have been proposed in the past decade, but there are seldom attempts to investigate the advantages and disadvantages of different detection mechanisms so that they can complement each other to achieve a better performance. Toward such a demand, this paper proposes a human action detection and recognition framework to bridge the semantic gap between low-level pixel intensity change and the high-level understanding of the meaning of an action. To achieve a robust estimation of the region of action with the complexities of an uncontrolled background, we propose the combination of the optical flow field and Harris3D corner detector to obtain a new spatial-temporal estimation in the video sequences. The action detection method, considering the integrated motion information, works well with the dynamic background and camera motion, and demonstrates the advantage of the proposed method of integrating multiple spatial-temporal cues. Then the local features (SIFT and STIP) extracted from the estimated region of action are used to learn the Universal Background Model (UBM) for the action recognition task. The experimental results on KTH and UCF YouTube Action (UCF11) data sets show that the proposed action detection and recognition framework can not only better estimate the region of action but also achieve better recognition accuracy comparing with the peer work

Research on standardization construction of information interoperability framework

There are various ways for various services to carry out accusation information interoperability. The establishment of a standardized accusation information interoperability framework can provide a way to solve the problem of diversified and complicated implementation of accusation information interoperability between systems. This paper analyzes and compares three types of design methods, centering on the Battle Management Language(BML), combined with the structural concepts of Service-Oriented Architecture(SOA) and Unified Architecture Framework(UAF). Finally, a directly connected structural framework was chosen to build, and a public service supporting structural framework including six levels of system, technology, resources, service, function and organization, and multiple elements such as ontology model, semantic mapping and model generation is constructed, providing theoretical support for the research on standardization of accusative information interoperability

Near-Duplicate Segments based news web video event mining

News web videos uploaded by general users usually include lots of post-processing effects (editing, inserted logo, etc.), which bring noise and affect the similarity comparison for news web video event mining. In this paper, a framework based on the concept of Near-Duplicate Segments (NDSs) which effectively integrates spatial and temporal information is proposed. After each video being divided into segments, those segments from different videos but sharing similar visual content are clustered into groups. Each group is named as an NDS, which infers the latent content relations among videos. The spatial-temporal local features are extracted and used to represent each video segment, which could effectively capture the main content of news web videos and omit the noise such as the disturbance/influence from video editing. Finally, the visual information is integrated with the textual information. The experiment demonstrates that our proposed framework is more effective than several existing methods with a significant improvement. •NDS which effectively integrates spatial and temporal information is proposed.•A framework based on the concept of NDS is proposed.•The AARM method is proposed to enhance the robustness of terms in MCA

Highly-Ordered Mesoporous Carbon Nitride with Ultrahigh Surface Area and Pore Volume as a Superior Dehydrogenation Catalyst

In this work, a highly ordered mesoporous carbon nitride nanorods with 971–1124 m² g^–1 of superhigh specific surface area, 1.31–1.79 cm³ g^–1 of ultralarge pore volume, bimodal mesostructure, and 9.3–23 wt % of high N content was prepared via a facile nanocasting approach using SBA-15 as template and hexamethylenetetramine as carbon nitride precursor, and the specific surface area and pore volume as well as N content are strongly dependent on the chosen precursor and pyrolysis temperature. The as-prepared materials were well characterized by HRTEM, FESEM, XRD, BET, Raman, FT-IR, XPS, and the textural structure and morphology were confirmed. The finding breaks through the bottleneck problems for fabricating mesoporous carbon nitride with both ultrahigh surface area and super large pore volume by employing an unexplored hexamethylenetetramine as carbon nitride precursor. The current synthetic strategy can be extended to the preparation of various mesoporous carbon nitride with different textural characteristics by using diverse templates under changeable preparation conditions. The developed mesoporous carbon nitride material with 750 °C of pyrolysis temperature exhibits high superior catalytic performance, ascribed to the promoting effect of nitrogen within the carbon matrix, the rich CO group and defect/edge feature on the surface, small size of graphitic crystallite, as well as the ultrahigh surface area and pore volume. It can also be concluded that the microstructures including bulk and surface structure features and surface chemical properties of the carbon-based materials have a decisive influence on their catalytic performance. The developed material can be employed in various organic transformations such as the base-catalyzed reactions, selective oxidation, dehydrogenation, photocatalysis, and electrocatalysis as well as acting as a novel and efficient candidate for CO₂ capture, supercapacitor, purification of contaminated water, and future drug-delivery systems

Syngas Production via Steam–CO₂ Dual Reforming of Methane over LA-Ni/ZrO₂ Catalyst Prepared by l‑Arginine Ligand-Assisted Strategy: Enhanced Activity and Stability

A highly dispersed supported nickel catalyst (LA-Ni/ZrO₂), synthesized by a facile l-arginine ligand-assisted incipient wetness impregnation (LA-IWI) approach, demonstrates much superior catalytic activity and exceptional stability for steam–CO₂ dual reforming of methane in comparison with the classical Ni/ZrO₂ catalyst by the IWI method. The origin of the enhanced activity and stability of the developed LA-Ni/ZrO₂ catalyst as well as the role of the Ni–{(l-Arg)} complex as the Ni precursor is revealed by employing diverse characterization techniques including X-ray diffraction (XRD), N₂ adsorption (BET), transmission electron microscopy (TEM), H₂ temperature-programmed reduction (H₂-TPR), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy (Raman), CO chemisorption, temperature-programmed hydrogenation (TPH), and thermogravimetric analysis (TGA). The superior catalytic activity of the developed LA-Ni/ZrO₂ catalyst to the classical Ni/ZrO₂ can be ascribed to the higher Ni dispersion, intensified Ni–support interaction, the enlarged oxygen vacancies, as well as the increased <i>t</i>-ZrO₂ content and enhanced reducibility of NiO led by oxygen vacancies. More interestingly, although a larger amount of coke depositing on the spent LA-Ni/ZrO₂ catalyst in comparison with that on the spent Ni/ZrO₂ can be observed by TGA and TPH measurement, the developed LA-Ni/ZrO₂ illustrates much higher catalytic stability to Ni/ZrO₂, ascribed to the superior thermal sintering resistance of Ni nanoparticles and the different coke morphologies confirmed by TEM images led by intensified interaction of Ni and the ZrO₂ support. The much superior catalytic activity and stability of the developed LA-Ni/ZrO₂ catalyst endows it to be a promising candidate for syngas production with diverse H₂/CO ratios via steam–CO₂ dual reforming of methane

Carbon Nitride Encapsulated Nanodiamond Hybrid with Improved Catalytic Performance for Clean and Energy-Saving Styrene Production via Direct Dehydrogenation of Ethylbenzene

In this work, the unconsolidated carbon-nitride-layer close-wrapped nanodiamond (H-ND) hybrid has been successfully synthesized by a facile two-step approach including the mechanical milling of ND powder and hexamethylenetetramine and the followed pyrolysis of hexamethylenetetramine. The unique microstructure and surface chemistry characteristics of the nanohybrid have been identified by employing diverse characterization techniques including field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), N₂ adsorption desorption (BET), X-ray diffraction (XRD), Raman spectroscopy (Raman), and X-ray photoelectron spectroscopy (XPS) analyses. Benefiting from the intensified synergistic effect between carbon nitride and nanodiamond, the as-synthesized H-ND hybrid carbocatalyst shows remarkably higher catalytic activity for oxidant- and steam-free direct dehydrogenation (DDH) of ethylbenzene than the nanodiamond (ND) and the previously developed mesoporous carbon nitride, which endows it to be a promising candidate for clean and energy-saving synthesis of styrene through DDH of ethylbenzene. Furthermore, this work also opens a new avenue for fabrication of diverse unconsolidated carbon nitride layers close wrapped nanocarbon hybrids with potential applications for diverse transformations owing to the intensified synergistic effect between carbon nitrides and the nanocarbons

Binary Mixtures of Highly Concentrated Tetraglyme and Hydrofluoroether as a Stable and Nonflammable Electrolyte for Li–O₂ Batteries

Developing a long-term stable electrolyte is one of the most enormous challenges for Li–O₂ batteries. Equally, the high flammability of frequently used solvents seriously weakens the electrolyte safety in Li–O₂ batteries, which inevitably restricts their commercial applications. Here, a binary mixture of highly concentrated tetraglyme electrolyte (HCG4) and 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether (TTE) was used for a novel electrolyte (HCG4/TTE) in Li–O₂ batteries, which exhibit good wettability, enhanced ionic conductivity, considerable nonflammability, and high electrochemical stability. Being a co-solvent, TTE can contribute to increasing ionic conductivity and to improving flame retardance of the as-prepared electrolyte. The cell with this novel electrolyte displays an enhanced cycling stability, resulting from the high electrochemical stability during cycling and the formation of electrochemically stable interfaces prevents parasitic reactions occurring on the Li anode. These results presented here demonstrate a novel electrolyte with a high electrochemical stability and considerable safety for Li–O₂ batteries

3D Foam-Like Composites of Mo₂C Nanorods Coated by N‑Doped Carbon: A Novel Self-Standing and Binder-Free O₂ Electrode for Li–O₂ Batteries

The development of self-standing and binder-free O₂ electrodes is significant for enhancing the total specific energy density and suppressing parasitic reactions for Li–O₂ batteries, which is still a formidable challenge thus far. Here, a three-dimensional foam-like composite composed of Mo₂C nanorods decorated by different amounts of N-doped carbon (Mo₂C-NR@<i>x</i>NC (<i>x</i> = 5, 11, and 16 wt %)) was directly employed as the O₂ electrode without applications of any binders and current collectors. Mo₂C-NR@<i>x</i>NC presents a network microstructure with interconnected macropore and mesoporous channels, which is beneficial to achieving fast Li⁺ migration and O₂ diffusion, facilitating the electrolyte impregnation, and providing enough space for Li₂O₂ storage. Additionally, the coated N-doped carbon layer can largely improve the electrochemical stability and conductivity of Mo₂C. The cell with Mo₂C-NR@11NC shows a considerable cyclability of 200 cycles with an overpotential of 0.28 V in the first cycle at a constant current density of 100 mA g^–1, a superior reversibility associated with the formation and decomposition of Li₂O₂ as desired, and a high electrochemical stability. On the basis of the experimental results, the electrochemical mechanism for the cell using Mo₂C-NR@11NC is proposed. These results represent a promising process in the development of a self-standing and binder-free foam-based electrode for Li–O₂ batteries

Second-Shell N Dopants Regulate Acidic O₂ Reduction Pathways on Isolated Pt Sites

Pt is a well-known benchmark catalyst in the acidic oxygen reduction reaction (ORR) that drives electrochemical O2-to-H2O conversion with maximum chemical energy-to-electricity efficiency. Once dispersing bulk Pt into isolated single atoms, however, the preferential ORR pathway remains a long-standing controversy due to their complex local coordination environment and diverse site density over substrates. Herein, using a set of carbon nanotube supported Pt–N–C single-atom catalysts, we demonstrate how the neighboring N dopants regulate the electronic structure of the Pt central atom and thus steer the ORR selectivity; that is, the O2-to-H2O2 conversion selectivity can be tailored from 10% to 85% at 0.3 V versus reversible hydrogen electrode. Moreover, via a comprehensive X-ray-radiated spectroscopy and shell-isolated nanoparticle-enhanced Raman spectroscopy analysis coupled with theoretical modeling, we reveal that a dominant pyridinic- and pyrrolic-N coordination within the first shell of Pt–N–C motifs favors the 4e– ORR, whereas the introduction of a second-shell graphitic-N dopant weakens *OOH binding on neighboring Pt sites and gives rise to a dominant 2e– ORR. These findings underscore the importance of the chemical environment effect for steering the electrochemical performance of single-atom catalysts