Hierarchical porous carbon with high areal energy density in supercapacitor has attracted extensive attention with increasing demand for compact and portable devices. Lignin based porous carbon ...monolith was fabricated via dual templates (P123 and silica nanoparticles) and carbonization procedure, where hierarchical porous structure with tuneable mesopore sizes and distributions could be modulated via incorporation of silica nanoparticles with size of 200 nm, 100 nm, and 7 nm, respectively. Due to higher surface area and optimized porous structure which facilitate fast ion diffusion, carbon monolith fabricated from silica nanoparticle of 7 nm exhibited superior electrochemical performance, which reached a high areal capacitance of 2.7 F cm−2 and excellent volumetric capacitance of 104.5 F cm−3 with mass loading of 13.6 mg cm−2 in 6 M KOH aqueous solution. Moreover, the symmetric cell assembled with this carbon electrode gave rise to a large amount of energy (131 μWh cm−2) at high power densities (1368 μW cm−2) and excellent cycle stability of 92.9% after 10 000 cycles, facilitating implementation of lignin-derived materials in commercial energy storage products.
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•Lignin derived hierarchical porous carbon monolith was fabricated by dual templates.•The porous structure can be tuned by the size and amount of silica nanoparticles.•High capacitance performance can be realized by optimizing porous structure.•2.7 F cm−2, 104.5 F cm−3, and 200.2 F g−1 were achieved at 0.1 A g−1.
Metal nanoclusters (NCs), including Au, Ag, Cu, Pt, Ni and alloy NCs, have become more and more popular sensor probes with good solubility, biocompatibility, size-dependent luminescence and ...catalysis. The development of electrochemiluminescent (ECL) and chemiluminescent (CL) analytical methods based on various metal NCs have become research hotspots. To improve ECL and CL performances, many strategies are proposed, from metal core to ligand, from intermolecular electron transfer to intramolecular electron transfer. Combined with a variety of amplification technology, i.e., nanostructure-based enhancement and biological signal amplification, highly sensitive ECL and CL analytical methods are developed. We have summarized the research progresses since 2016. Also, we discuss the current challenges and perspectives on the development of this area.
Abstract (704) Interamnia is one of the largest asteroids located in the outer main-belt region, which may contain a large amount of water ice underneath its surface. We observe this asteroid using ...8.2 m Subaru telescope at mid-infrared wave bands and utilize a thermophysical model for realistic surface layers to analyze mid-infrared data from Subaru along with those of IRAS, AKARI, and Wide-field Infrared Survey Explorer (WISE)/NEOWISE. We optimize the method to convert the WISE magnitude to thermal infrared flux with temperature-dependent color corrections, which can provide significant references for main-belt asteroids at a large heliocentric distance with low surface temperature. We derive best-fitting thermal parameters of Interamnia—a mean regolith grain size of 190 − 180 + 460 μ m, with a roughness of 0.30 − 0.17 + 0.35 and rms slope of 27 − 9 + 13 deg, thereby producing thermal inertia ranging from 9 to 92 Jm −2 s −1/2 K −1 due to seasonal temperature variation. The geometric albedo and effective diameter are evaluated to be 0.0472 − 0.0031 + 0.0033 and 339 − 11 + 12 km , respectively, being indicative of a bulk density of 1.86 ± 0.63 g cm −3 . The low thermal inertia is consistent with typical B/C-type asteroids with D ≥ 100 km. The tiny regolith grain size suggests the presence of a fine regolith on the surface of Interamnia. Moreover, the seasonal and diurnal temperature distribution indicates that thermal features between the southern and northern hemispheres appear to be very different. Finally, we present an estimation of volume fraction of water ice of 9%–66% from the published grain density and porosity of carbonaceous chondrites.
Abstract Contactless bubble manipulation with a high spatiotemporal resolution brings a qualitative leap forward in a variety of applications. Despite considerable advances, light-induced bubble ...maneuvering remains challenging in terms of robust transportation, splitting and detachment. Here, a photopyroelectric slippery surface (PESS) with a sandwich structure is constructed to achieve the versatile bubble manipulation. Due to the generated dielectric wetting and nonuniform electric field under the irradiation of near infrared (NIR) light, a bubble is subject to both the Laplace force and dielectrophoresis force, enabling a high-efficiency bubble steering. We demonstrate that the splitting, merging and detachment of underwater bubbles can be achieved with high flexibility and precision, high velocity and agile direction maneuverability. We further extend the capability of bubble control to microrobots for cargo transportation, micropart assembly and transmission of gear structures. We envision this robust bubble manipulation strategy on the PESS would provide a valuable platform for various bubble-involved processes, ranging from microfluidic devices to soft robotics.
The object detection of natural images tends to obtain advanced semantic information through multiple convolutions and pooling, ignoring the detailed information in the feature map. Pixel-level ...images may be the target we are looking for in remote sensing images. This article designs a new attention mechanism that can fully utilize the spatial and channel information of the image, strengthen the region of interest, and try to protect the image's original information. Find the most influential location information in the spatial dimension and the most influential feature map in the channel dimension. Strengthen important channels and positions in the feature map to make vital information stronger and weak information not lost. Combine the designed attention mechanism with existing modules to enhance YOLO-V7 detection capability. We have merged two publicly available remote sensing image datasets, increasing object types, and richer appearance features, which can better detect model performance. Experimental results on an improved dataset have shown that the enhanced model in this paper can improve the detection ability of small and medium-sized targets in complex backgrounds, with a 1% increase in mean average precision (mAP) value and a maximum improvement of 8.2% for single-class targets. Medium targets such as airports, dams, and soccer ball fields also increase by about 5%. We also conducted experiments on the DOTA1.0 dataset to demonstrate that mAP improved by 1.1%, with 13 target categories having higher APs. The improved model reduces computational complexity by 2.7%, which is very user-friendly for embedded devices.
Abstract The active asteroid 311P/PanSTARRS is one of the two targets of the planned Chinese asteroid exploration mission Tianwen-2. During 2013, 311P experienced several mass-loss events and ...exhibited multiple comet-like tails. Here we analyze the morphology and surface brightness of the tails to investigate the dust environment around the nucleus and the mechanism of activities. We enhance the features of the tails using image processing techniques to obtain information about the morphologies of the tails, and fit the processed images with syndyne–synchrone diagrams. The fitting results give estimations of the upper limits of the durations (2–8 days) of eruptions and the dust size ranges (0.006 –38.9 mm) in the tails. The results of surface photometry performed for each dust tail show that the brightness distribution index of each tail ranged from approximately −1.81 to 0 and the dust size distribution indices of 311P's tails ranged from −2.29 to −1.45. The quantity of particles in each tail ranged from 0.5 to 8 × 10 6 kg, which leads to a total dust-loss quantity of 3.0 × 10 7 kg and a mass-loss rate of 1.59 kg s −1 . Sublimation, continuous impacts, or tidal forces of planets are excluded as explanations for 311P’s activities, and rotational instability remains a possible activation cause without strong evidence against it.
Grape gray mold disease (
) is widespread during grape production especially in
and causes enormous losses to the grape industry. In nature, the grapevine cultivar 'Beta ' (
×
) showed high ...resistance to grape gray mold. Until now, the candidate genes and their mechanism of gray mold resistance were poorly understood. In this study, we firstly conducted quantitative trait locus (QTL) mapping for grape gray mold resistance based on two hybrid offspring populations that showed wide separation in gray mold resistance. Notably, two stable QTL related to gray mold resistance were detected and located on linkage groups LG2 and LG7. The phenotypic variance ranged from 6.86% to 13.70% on LG2 and 4.40% to 11.40% on LG7. Combined with RNA sequencing (RNA-seq), one structural gene
(Vitvi02g00982) and three transcription factors
(Vitvi00g00859),
(Vitvi08g01843), and
(Vitvi07g01847) that may be involved in
expression and grape gray mold resistance were selected. This discovery of candidate gray mold resistance genes will provide an important theoretical reference for grape gray mold resistance mechanisms, research, and gray mold-resistant grape cultivar breeding in the future.
Accurate detection of locations of indoor high-density crowds is crucial for early warning and emergency rescue during indoor safety accidents. The spatial structure of indoor environments is more ...complicated than outdoor environments. The locations of indoor high-density crowds are more likely to be the sites of security accidents. Existing detection methods for high-density crowd locations mostly focus on outdoor environments, and relatively few detection methods exist for indoor environments. This study proposes a novel detection framework for high-density indoor crowd locations termed IndoorSRC (Simplification–Reconstruction–Cluster). In this paper, a novel indoor spatiotemporal clustering algorithm called Indoor-STAGNES is proposed to detect the indoor trajectory stay points to simplify indoor movement trajectory. Then, we propose use of a Kalman filter algorithm to reconstruct the indoor trajectory and properly align and resample the data. Finally, an indoor spatiotemporal density clustering algorithm called Indoor-STOPTICS is proposed to detect the locations of high-density crowds in the indoor environment from the reconstructed trajectory. Extensive experiments were conducted using indoor Wi-Fi positioning datasets collected from a shopping mall. The results show that the IndoorSRC framework evidently outperforms the existing baseline method in terms of detection performance.
In this study, the martensitic stainless-steel powder had been successfully deposited on the surfaces of 1045 wrought steel substrates using five types of laser metal deposition strategies. The ...results showed that a thin buffer layer can be naturally generated in-between the deposition layer and substrate owning to the dilution effect, producing functionally graded structures consisted of martensite dendrite matrices and intermetallic phases (e.g., M23(C, B)6). Unfortunately, the poor deformation characteristic of natural buffer layers can exacerbate the risk of cracking, leading to an incompatibility between martensitic stainless steel and forming steel. A thick artificial buffer layer was then designed by addition of Inconel 625 powder. Because of the formation of graded austenite phase in the artificial buffer layer, the yield strength of specimen was enhanced significantly. Hence, our study can be used for manufacture of reliable moulds with high surface hardness and structural strength and may be helpful in further developing hybrid forming strategy in the field of mould manufacture. When subjected to stress impact during mould filling, the artificial buffer layer with functionally graded properties would have a perfect capability to bear the deformation as the load increased, dramatically improving the reliability and functionality of moulds.
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•The buffer layers was formed due to the dilution effect.•The artificial buffer layer had perfect functionally graded properties.•A hybrid mould with artificial buffer layer was fabricated by LMD.
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