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3D hand pose and shape estimation from monocular RGB via efficient 2D cues

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Computational Visual Media 2024年第1期10卷 79-96页

作者： Fenghao zhang Lin Zhao Shengling Li Wanjuan Su Liman Liu Wenbing tao Hubei Key Laboratory of Medical Information Analysis and Tumor Diagnosis&Treatment School of Biomedical EngineeringSouth Central Minzu UniversityWuhan430074China National Key Laboratory of Science and Technology of Multi-spectral Information Processing School of Artificial Intelligence and AutomationHuazhong University of Science and TechnologyWuhan430074China

Estimating 3D hand shape from a single-view RGB image is important for many ***,the diversity of hand shapes and postures,depth ambiguity,and occlusion may result in pose errors and noisy hand *** full use of 2D cues such as 2D pose can effectively improve the quality of 3D human hand shape *** this paper,we use 2D joint heatmaps to obtain spatial details for robust pose *** also introduce a depth-independent 2D mesh to avoid depth ambiguity in mesh regression for efficient hand-image *** method has four cascaded stages:2D cue extraction,pose feature encoding,initial reconstruction,and reconstruction ***,we first encode the image to determine semantic features during 2D cue extraction;this is also used to predict hand joints and for ***,during the pose feature encoding stage,we use a hand joints encoder to learn spatial information from the joint ***,a coarse 3D hand mesh and 2D mesh are obtained in the initial reconstruction step;a mesh squeeze-and-excitation block is used to fuse different hand features to enhance perception of 3D hand ***,a global mesh refinement stage learns non-local relations between vertices of the hand mesh from the predicted 2D mesh,to predict an offset hand mesh to fine-tune the reconstruction *** and qualitative results on the FreiHAND benchmark dataset demonstrate that our approach achieves state-of-the-art performance.

关键词： hand 3D reconstruction deep learning image features 3D mesh

Unlocking supercapacitive energy storage potential:Catalyzing electrochemically inactive manganese oxides to active MnO_(2)via heterostructure reconstruction

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Nano Research 2024年第7期17卷 5897-5906页

作者： Baohong zhang tao Jiang Xinyan Zhou Xiaoyu Fan Binbin Jia Lidong Li School of Chemistry Beihang UniversityBeijing 100191China College of Materials and Chemical Engineering Key Laboratory of Inorganic Nonmetallic Crystalline and Energy Conversion MaterialsChinaThree Gorges UniversityYichang 443002China Chinese Academy of Sciences(CAS)Key Laboratory of Nanosystem and Hierarchy Fabrication CAS Center for Excellence in NanoscienceNational Center for Nanoscience and TechnologyBeijing 100190China Shanghai GTX Semiconductor Co. Ltd.Shanghai 201806China

Advancing supercapacitor system performance hinges on the innovation of novel electrode materials seamlessly integrated within distinct ***,we introduce a direct approach for crafting nanorod arrays featuring crystalline/amorphous CuO/MnO_(2)−*** reconfigured heterostructure results in an elevated content of electrochemically active MnO_(2).The nanorod arrays serve as efficient capacitive anodes and are easily prepared via low-potential electrochemical *** resulting structure spontaneously forms a p–n heterojunction,developing a built-in electric field that dramatically facilitates the charge transport *** intrinsic electric field,in conjunction with the crystalline/amorphous architecture,enables a large capacitance of 1.0 F·cm^(−2)at 1.0 mA·cm^(−2),an ultrahigh rate capability of approximately 85.4%at 15 mA·cm^(−2),and stable cycling performance with 92.4%retention after 10,000 *** calculations reveal that the presence of heterojunctions allows for the optimization of the electronic structure of this composite,leading to improved conductivity and optimized OH−adsorption *** work provides new insights into the rational design of heterogeneous nanostructures,which hold great potential in energy storage applications.

关键词： reconfiguration active MnO_(2) crystalline/amorphous structure p-n heterojunction supercapacitor

Robust cooperative multi-agent reinforcement learning via multi-view message certification

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Science China(Information Sciences) 2024年第4期67卷 131-145页

作者： Lei YUAN tao JIANG Lihe LI Feng CHEN Zongzhang zhang Yang YU National Key Laboratory for Novel Software Technology Nanjing University Polixir Technologies

Many multi-agent scenarios require message sharing among agents to promote coordination,hastening the robustness of multi-agent communication when policies are deployed in a message perturbation environment. Major relevant studies tackle this issue under specific assumptions, like a limited number of message channels would sustain perturbations, limiting the efficiency in complex scenarios. In this paper,we take a further step in addressing this issue by learning a robust cooperative multi-agent reinforcement learning via multi-view message certification, dubbed CroMAC. Agents trained under CroMAC can obtain guaranteed lower bounds on state-action values to identify and choose the optimal action under a worst-case deviation when the received messages are perturbed. Concretely, we first model multi-agent communication as a multi-view problem, where every message stands for a view of the state. Then we extract a certificated joint message representation by a multi-view variational autoencoder(MVAE) that uses a product-of-experts inference network. For the optimization phase, we do perturbations in the latent space of the state for a certificate guarantee. Then the learned joint message representation is used to approximate the certificated state representation during training. Extensive experiments in several cooperative multi-agent benchmarks validate the effectiveness of the proposed CroMAC.

关键词： multi-agent reinforcement learning robust communication adversarial training multi-view learning message certification

Tailoring the surface and interface structures of photocatalysts to enhance hydrogen production

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Science China Chemistry 2024年第4期67卷 1161-1174页

作者： tao zhang Pengfei Wang Shuai Yue Fei Li Zhiyong Zhao Sihui Zhan MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control College of Environmental Science and EngineeringNankai UniversityTianjin 300350China

Photocatalytic water splitting using semiconductor photocatalysts is a promising approach for the production of carbon-neutral,sustainable and clean hydrogen ***,the separation and transport of photoinduced carriers are generally considered to be rate-limiting steps,and their low efficiency remains a major ***,much effort has been devoted to developing new strategies in surface/interface engineering of photocatalysts to improve the dynamics of charge separation/*** feature article briefly summarizes recent advances in photocatalyst surface/interface engineering by our research group,which have been achieved through the design of various novel photocatalysts,including interfacial modulation,heterostructure construction,heteroatom doping,single atom and diatom *** article is divided into three parts:first,we briefly introduce the three key processes involved in solar water splitting and reveal relationships between the properties of nanostructural photocatalysts and the fundamentals of water splitting;second,we detail methods and strategies for surface and interfacial structures to improve the efficiency of the fundamental processes,especially charge separation;finally,we explore prospects for photocatalytic water splitting *** article provides a valuable resource and strategies for researchers currently working in the field of photocatalytic water splitting.

关键词： photocatalytic water splitting surface/interface structures dual-functional photocatalysis

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Quantifying the Effects of Near-Surface Viscosity on Seismic Acquisition Geometry: A case study from Chepaizi Exploration Area, Junggar Basin (NW China)

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Applied Geophysics 2024年第3期21卷 433-439,616页

作者： Hongqin Ren tao Liu Xu zhang Jian zhang Renwei Ding Shengli Branch Sinopec Geophysical Co.Ltd.Shandong Dongying 257086China College of Earth Science and Engineering Shandong University of Science and TechnologyShandong Qingdao 266590China

The Chepaizi Exploration Area,Junggar Basin(NW China)holds substantial importance for seismic exploration endeavors,yet it poses notable challenges due to the intricate nature of its subsurface and near-surface *** address these challenges,we introduce a novel and comprehensive workflow tailored to evaluate and optimize seismic acquisition geometries while considering the impacts of near-surface *** integrating geological knowledge,historical seismic data,and subsurface modeling,we conduct simulations employing the visco-acoustic wave equation and reverse-time migration to produce detailed subsurface *** quality of these images is quantitatively evaluated using a local similarity metric,a pivotal tool for evaluating the accuracy of seismic *** culmination of this workflow results in an automated optimization strategy for acquisition geometries that enhances subsurface *** proposed methodology underscores the importance of incorporating near-surface viscosity effects in seismic imaging,offering a robust framework for improving the accuracy of subsurface ***,we aim to contribute to the advancement of seismic imaging methodologies by providing valuable insights for achieving high-quality seismic exploration outcomes in regions characterized by complex subsurface and near-surface conditions.

关键词： seismic acquisition visco-acoustic reverse-time migration local similarity

An improved GNSS ambiguity best integer equivariant estimation method with Laplacian distribution for urban low-cost RTK positioning

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Satellite Navigation 2024年第1期5卷 109-124页

作者： Ying Liu Wanke Liu Xiaohong zhang Yantao Liang Xianlu tao Liye Ma School of Geodesy and Geomatics Hubei Luojia LaboratoryWuhan University129 Luoyu RoadWuhan430079HubeiChina Chinese Antarctic Center of Surveying and Mapping Wuhan University129 Luoyu RoadWuhan430079HubeiChina School of Instrument Science and Engineering Southeast UniversityNanjingJiangsuChina The 54 Research Institute of China Electronics Technology Group CorporationShijiazhuang050081HebeiChina State Key Laboratory of Satellite Navigation System and Equipment Technology Shijiazhuang050081HebeiChina

The integer least squares(ILS)estimation is commonly used for carrier phase ambiguity resolution(AR).More recently,the best integer equivariant(BIE)estimation has also attracted an attention for complex application scenarios,which exhibits higher reliability by a weighted fusion of integer ***,traditional BIE estimation with Gaussian distribution(GBIE)faces challenges in fully utilizing the advantages of BIE for urban low-cost positioning,mainly due to the presence of outliers and unmodeled *** this end,an improved BIE estimation method with Laplacian distribution(LBIE)is proposed,and several key issues are discussed,including the weight function of LBIE,determination of the candidates included based on the OIA test,and derivation of the variance of LBIE solutions for reliability *** results show that the proposed LBIE method has the positioning accuracy similar to the BIE using multivariate t-distribution(TBIE),and significantly outperforms the ILS-PAR and GBIE *** an urban expressway test with a Huawei Mate40 smartphone,the LBIE method has positioning errors of less than 0.5 m in three directions and obtains over 50%improvements compared to the ILS-PAR and GBIE *** an urban canyon test with a low-cost receiver STA8100 produced by STMicroelectronics,the positioning accuracy of LBIE in three directions is 0.112 m,0.107 m,and 0.252 m,respectively,with improvements of 17.6%,27.2%,and 26.1%compared to GBIE,and 23.3%,28.2%,and 30.6%compared to ***,its computational time increases by 30–40%compared to ILS-PAR and is approximately half of that using TBIE.

关键词： Ambiguity resolution Best integer equivariant estimation Laplacian distribution Urban environments Low-cost GNSS receivers Real-time kinematic

Engineering of geometrical configurations in dual-atom catalysts for electrocatalytic applications

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Journal of Energy Chemistry 2024年第7期94卷 273-287页

作者： tao zhang Yifan Liu Liang Xue Jingwen Sun Pan Xiong Junwu Zhu Key Laboratory for Soft Chemistry and Functional Materials of Ministry Education School of Chemistry and Chemical EngineeringNanjing University of Science and TechnologyNanjing210094JiangsuChina

Geometrical configurations play a crucial role in dual-atom catalysts(DACs)for electrocatalytic *** progress has been made to design DACs electrocatalysts with various geometri-cal configurations,but in-depth understanding the relationship between geometrical configurations and metal-metal interaction mechanisms for designing targeted DACs is still *** this review,the recent progress in engineering of geometrical configurations of DACs is systematically *** on the polarity of geometrical configuration,DACs can be classified into two different types that are homonuclear and heteronuclear ***,with regard to the geometrical configurations of the active sites,homonuclear DACs are identified into adjacent and bridged configurations,and heteronuclear DACs can be classified into adjacent,bridged,and separated ***,metal-metal interactions in DACs with different geometrical configurations are ***,the applications of DACs in different electrocatalytic reactions are discussed,including the oxygen reduction reaction(ORR),oxygen evolution reaction(OER),hydrogen evolution reaction(HER),and other ***,the future challenges and perspectives for advancements in DACs are *** review aims to provide inspiration for the design of highly effcient DACs towards energy relatedapplications.

关键词： Dual-atom catalysts Geometrical configurations Homonuclear Heteronuclear Electrocatalysis

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Effect of low-speed waterjet pressure on the rock-breaking performance of unsubmerged cavitating abrasive waterjet

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Petroleum Science 2024年第4期21卷 2638-2649页

作者： Chen-Xing Fan Deng Li Yong Kang Hai-tao zhang Hubei Key Laboratory of Waterjet Theory and New Technology Wuhan University School of Power and Mechanical Engineering Wuhan University

Unsubmerged cavitating abrasive waterjet(UCAWJ) has been shown to artificially create a submerged environment that produces shear cavitation, which effectively enhances rock-breaking performance. The shear cavitation generation and collapse intensity depend on the pressure difference between the intermediate high-speed abrasive waterjet and the coaxial low-speed waterjet. However, the effect of the pressure of the coaxial low-speed waterjet is pending. For this purpose, the effect of low-speed waterjet pressure on rock-breaking performance at different standoff distances was experimentally investigated,and the effects of erosion time and ruby nozzle diameter on erosion performance were discussed. Finally,the micromorphology of the sandstone was observed at different locations. The results show that increased erosion time and ruby nozzle diameter can significantly improve the rock-breaking performance. At different standoff distances, the mass loss increases first and then decreases with the increase of low-speed waterjet pressure, the maximum mass loss is 10.4 g at a low-speed waterjet pressure of0.09 MPa. The surface morphology of cavitation erosion was measured using a 3D profiler, the increase in both erosion depth and surface roughness indicated a significant increase in the intensity of the shear cavitation collapse. At a low-speed waterjet pressure of 0.18 MPa, the cavitation erosion surface depth can reach 600 μm with a roughness of 127 μm.

关键词： Rock-breaking Coaxial low-speed waterjet pressure Abrasive waterjet Cavitation Unsubmerged environment

Close-packed layer spacing as a practical guideline for structure symmetry manipulation of IV-VI/I-V-VI_(2) thermoelectrics

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InfoMat 2024年第2期6卷 99-106页

作者： tao Jin Long Yang Xinyue zhang Wen Li Yanzhong Pei Interdisciplinary Materials Research Center School of Materials Science and EngineeringTongji UniversityShanghaithe People's Republic of China

The crystal-structure symmetry in real space can be inherited in the reciprocal space,making high-symmetry materials the top candidates for thermoelectrics due to their potential for significant electronic band degeneracy.A practical indicator that can quantitatively describe structural changes would help facilitate the advanced thermoelectric material *** face-centered cubic structures,the spatial environment of the same crystallographic plane family is isotropic,such that the distances between the close-packed layers can be derived from the atomic distances within the *** by this,the relationship between inter-and intra-layer geometric information can be used to compare crystal structures with their desired cubic *** close-packed layer spacing was found to be a practical guideline of crystal structure symmetry in IV-VI chalcogenides and I-V-VI_(2) ternary semiconductors,both of which are historically important *** continuous structural evolution toward high symmetry can be described by the layer spacing when temperature or/and composition change,which is demonstrated by a series of pristine and alloyed thermoelectric materials in this *** layerspacing-based guideline provides a quantitative pathway for manipulating crystal structures to improve the electrical and thermal properties of thermoelectric materials.

关键词： phase transition structure manipulation thermoelectric materials x-ray diffraction