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Reshaping Li–Mg hybrid batteries:Epitaxial electrodeposition and spatial confinement on MgMOF substrates via the lattice‐matching strategy

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Carbon Energy 2024年第8期6卷 248-261页

作者： Yongqin Wang fulin Cheng Jiawen Ji Chenyang Cai Yu fu School of Materials Science and Engineering Co‐Innovation Center of Efficient Processing and Utilization of Forest ResourceNanjing Forestry UniversityNanjingJiangsuChina

The emergence of Li–Mg hybrid batteries has been receiving attention,owing to their enhanced electrochemical kinetics and reduced ***,the persistent challenge of uneven Mg electrodeposition remains a significant impediment to their practical ***,we developed an ingenious approach that centered around epitaxial electrocrystallization and meticulously controlled growth of magnesium crystals on a specialized MgMOF *** chosen MgMOF substrate demonstrated a robust affinity for magnesium and showed minimal lattice misfit with Mg,establishing the crucial prerequisites for successful heteroepitaxial ***,the incorporation of periodic electric fields and successive nanochannels within the MgMOF structure created a spatially confined environment that considerably promoted uniform magnesium nucleation at the molecular *** inspiration from the“blockchain”concept prevalent in the realm of big data,we seamlessly integrated a conductive polypyrrole framework,acting as a connecting“chain,”to interlink the“blocks”comprising the MgMOF *** innovative design significantly amplified charge‐transfer efficiency,thereby increasing overall electrochemical *** resulting architecture(MgMOF@PPy@CC)served as an exceptional host for heteroepitaxial Mg electrodeposition,showcasing remarkable electrostripping/plating kinetics and excellent cycling ***,a symmetrical cell incorporating the MgMOF@PPy@CC electrode demonstrated impressive stability even under ultrahigh current density conditions(10mAcm–2),maintaining operation for an extended 1200 h,surpassing previously reported ***,on coupling the MgMOF@PPy@CC anode with a Mo_(6)S_(8) cathode,the assembled battery showed an extended lifespan of 10,000 cycles at 70 C,with an outstanding capacity retention of 96.23%.This study provides a fresh perspective on the rational design of epitaxial electrocrystallizat

关键词： epitaxial electrodeposition lattice‐matching strategy Li-Mg hybrid batteries MOF substrate spatial confinement

Meta label associated loss for fine-grained visual recognition

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Science China(Information Sciences) 2024年第6期67卷 230-247页

作者： Yanchao LI fu XIAO Hao LI Qun LI Shui YU School of Computer Science Nanjing University of Posts and Telecommunications School of Network Engineering Zhoukou Normal University School of Computer Science University of Technology Sydney

Recently, intensive attempts have been made to design robust models for fine-grained visual recognition, most notably are the impressive gains for training with noisy labels by incorporating a reweighting strategy into a meta-learning framework. However, it is limited to up or downweighting the contribution of an instance for label reweighting approaches in the learning process. To solve this issue, a novel noise-tolerant method with auxiliary web data is proposed. Specifically, first, the associations made from embeddings of well-labeled data with those of web data and back at the same class are measured. Next, its association probability is employed as a weighting fusion strategy into angular margin-based loss, which makes the trained model robust to noisy datasets. To reduce the influence of the gap between the well-labeled and noisy web data, a bridge schema is proposed via the corresponding loss that encourages the learned embeddings to be coherent. Lastly, the formulation is encapsulated into the meta-learning framework, which can reduce the overfitting of models and learn the network parameters to be noise-tolerant. Extensive experiments are performed on benchmark datasets, and the results clearly show the superiority of the proposed method over existing state-of-the-art approaches.

关键词： label associated loss weighting noisy samples fine-grained visual recognition noise-tolerant learning meta-learning

Editorial:special topic on heterojunction in photocatalysts

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Science China Materials 2024年第2期67卷 379-381页

作者： Jiaguo Yu Xin Li Junwei fu Kai Dai Laboratory of Solar fuel Faculty of Materials Science and ChemistryChina University of GeosciencesWuhan 430078China Institute of Biomass Engineering Key Laboratory of Energy Plants Resource and UtilizationMinistry of Agriculture and Rural AffairsSouth China Agricultural UniversityGuangzhou 510642China Hunan Joint International Research Center for Carbon Dioxide Resource Utilization State Key Laboratory of Powder MetallurgySchool of PhysicsCentral South UniversityChangsha 410083China Anhui Province Key Laboratory of Pollutant Sensitive Materials and Environmental Remediation College of Physics and Electronic InformationHuaibei Normal UniversityHuaibei 235000China

To suppress the recombination of photogenerated electron and hole in single photocatalysts,an important method is to design heterojunction by combining two *** method has widely used to enhance the photocatalytic performance of the *** the begining,most people use type-Ⅱcharge carrier transfer mechanism to explain the emhanced activity of the composite semiconductors.

关键词： composite heterojunction method

Learning group interaction for sports video understanding from a perspective of athlete

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Frontiers of Computer Science 2024年第4期18卷 175-188页

作者： Rui HE Zehua fu Qingjie LIU Yunhong WANG Xunxun CHEN Intelligent Recognition and Image Processing(IRIP)Lab School of Computer Science and EngineeringBeihang UniversityBeijing 100191China Hangzhou Innovation Institute Behang UniversityHangzhou 310051China National Computer Network Emergency Response Technical Team/Coordination Center of China(CNCERT or CNCERT/CC) Beijing 100029China

Learning activities interactions between small groups is a key step in understanding team sports *** research focusing on team sports videos can be strictly regarded from the perspective of the audience rather than the *** team sports videos such as volleyball and basketball videos,there are plenty of intra-team and inter-team *** this paper,a new task named Group Scene Graph Generation is introduced to better understand intra-team relations and inter-team relations in sports *** tackle this problem,a novel Hierarchical Relation Network is *** all players in a video are finely divided into two teams,the feature of the two teams’activities and interactions will be enhanced by Graph Convolutional Networks,which are finally recognized to generate Group Scene *** evaluation,built on Volleyball dataset with additional 9660 team activity labels,a Volleyball+dataset is proposed.A baseline is set for better comparison and our experimental results demonstrate the effectiveness of our ***,the idea of our method can be directly utilized in another video-based task,Group Activity *** show the priority of our method and display the link between the two ***,from the athlete’s view,we elaborately present an interpretation that shows how to utilize Group Scene Graph to analyze teams’activities and provide professional gaming suggestions.

关键词： group scene graph group activity recognition scene graph generation graph convolutional network sports video understanding

Ambarzumyan's Theorem for the Dirac Operator on Equilateral Tree Graphs

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Acta Mathematicae Applicatae Sinica 2024年第2期40卷 568-576页

作者： Dong-Jie WU Xin-Jian XU Chuan-fu YANG Department of Mathematics School of Mathematics and StatisticsNanjing University of Science and TechnologyNanjing 210094China

The classical Ambarzumyan’s theorem states that if the Neumann eigenvalues of the Sturm-Liouville operator-d^(2)/dx^(2)+q with an integrable real-valued potential q on[0,π] are {n^(2):n≥0},then q=0 for almost all x∈[0,π].In this work,the classical Ambarzumyan’s theorem is extended to the Dirac operator on equilateral tree *** prove that if the spectrum of the Dirac operator on graphs coincides with the unperturbed case,then the potential is identically zero.

关键词： dirac operator quantum graph Ambarzumyan’s theorem inverse spectral problem

Influence of in situ formed spinel in bonding phase on mechanical properties and air permeability of magnesia-chrome porous purging materials

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Journal of Iron and Steel Research International 2024年第6期31卷 1459-1472页

作者： Yi An Hao Liu Zhou-fu Wang Yan Ma Xi-tang Wang The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina

Magnesia-chrome porous purging plugs are crucial functional components to remove inclusions and stabilize the flow field during iron and steel ***,practical applications of magnesia-chrome porous purging materials are stil hampered by the poor scouring resistance to molten steel and unstable air permeability owing to their low mechanical properties and uncontrollable pore ***,the particle-packing type magnesiachrome porous purging materials reinforced by in situ formed spinel were prepared using fused magnesia-chrome particles and Al powders as major raw *** results show that in situ formed spinel solid solutions in bonding phase led to the decreased median pore size and increased pore surface fractal dimension from the reactions between Al powders and magnesia-chrome particles and along with high-temperature sintering,bonding between magnesia-chrome particles and the resultant mechanical properties of materials were greatly ***,the results of air permeability tests and polynomial ftting indicated that the formation of spinel solid solutions was the main contributing factor for controllable air permeability,and pressure drop of porous purging materials was positively correlated with surface fractal dimension of ***,the as-prepared porous purging materials added with 6 wt.%Al powders obtained the maximum cold crushing strength(54.2 MPa)and hot modulus of rupture(12.9 MPa)with median pore size of 24.06μm and ftting non-Darcian permeability coefficient of 0.97×10^(-6)m.

关键词： Magnesia Chrome porous purging material Metallic Al-Spinel Mechanical strength Air permeability

Temperature field characteristics of CF/PEEK thermoplastic composites formed by automated fiber placement using hot gas torch with slit structure nozzle

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Chinese Journal of Aeronautics 2024年第6期37卷 392-409页

作者： Ziang JIN Shouzheng SUN Sunil Chandrakant JOSHI Zhenyu HAN Hongya fu State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001China School of Mechanical and Aerospace Engineering Nanyang Technological UniversitySingapore 639798Singapore

In-situ consolidation forming of high-performance thermoplastic composites by Automated Fiber Placement(AFP)is of significant interest in *** the laying process,the heating temperature has a great influence on the quality of the formed components.A threedimensional heat transfer finite element model of Carbon Fiber(CF)/Polyether Ether Ketone(PEEK)heated by Slit Structure Nozzle Hot Gas Torch(SSNHGT)assisted AFP is *** influence of gas flow rate,heat transfer distance,and laying speed on heating temperature is *** results show that the overall temperature increases and then decreases as the gas flow rate *** the increase in heat transfer distance and laying speed,the overall temperature ***,the gas flow rate has the greatest influence on the temperature of CF/PEEK being heated,followed by the laying speed and finally the heat transfer ***,the model can also be extended to other fiber-reinforced polymer composites formed by hot gas torch assisted AFP,which can guide the optimization of process parameters for subsequent heating temperature control.

关键词： Fiber reinforced plastics Thermoplastics Heating temperature Automated fiber placement CF/PEEK

Effects of diamond particle size on microstructure and properties of diamond/Al-12Si composites prepared by vacuum-assisted pressure infiltration

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China Foundry 2024年第4期21卷 360-368页

作者： Jia-ping fu Can-xu Zhou Guo-fa Mi Yuan Liu School of Materials Science and Engineering Henan Polytechnic UniversityJiaozuo 454100HenanChina School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China Key Laboratory for Advanced Materials Processing Technology Ministry of EducationBeijing 100084China

Diamond/aluminium composites have attracted attention in the field of thermal management of electronic packaging for their excellent *** order to solve the interfacial problem between diamond and aluminium,a novel process combining pressure infiltration with vacuum-assisted technology was proposed to prepare diamond/aluminum *** effect of diamond particle size on the microstructure and properties of the diamond/Al-12Si composites was *** results show that the diamond/Al-12Si composites exhibit high relative density and a uniform *** thermal conductivity and coefficient of thermal expansion increase with increasing particle size,while the bending strength exhibits the opposite *** the average diamond particle size increases from 45μm to 425μm,the thermal conductivity of the composites increases from 455 W·m^(-1)·K^(-1)to 713 W·m^(-1)·K^(-1)and the coefficient of thermal expansion increases from 4.97×10^(-6)K^(-1)to 6.72×10^(-6)K^(-1),while the bending strength decreases from 353 MPa to 246 *** research demonstrates that high-quality composites can be prepared by the vacuum-assisted pressure infiltration process and the thermal conductivity of the composites can be effectively improved by increasing the diamond particle size.

关键词： diamond/aluminum composites thermal conductivity electronic packaging vacuum-assisted pressure infiltration

Distribution and geochemical significance of alkylbenzenes for crude oil with different depositional environments and thermal maturities

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Petroleum Science 2024年第2期21卷 777-790页

作者： Bing-Kun Meng Dao-fu Song Yuan Chen Sheng-Bao Shi School of Petroleum Engineering and Environmental Engineering Yan'an UniversityYan'an716000ShaanxiChina State Key Laboratory of Petroleum Resources and Prospecting College of GeosciencesChina University of PetroleumBeijing102249China

A total of 45 alkylbenzenes were detected and identified in crude oils with different depositional environments and thermal maturities from the Tarim Basin,Beibuwan Basin,and Songliao Basin using comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry(GC×GCTOFMS).By analyzing the distribution characteristics of C0-C5alkylbenzenes,it is found that the content of some alkylbenzenes varies greatly in crude *** on the distribution characteristics of 1,2,4,5-tetramethylbenzene(Te MB)and 1,2,3,4-Te MB,the ratio of 1,2,4,5-Te MB to 1,2,3,4-Te MB is proposed to indicate the organic matter origin and depositional environment of ancient *** samples originated mainly from lower hydrobiont,algae,bacteria and source rocks deposited under reducing/anoxic conditions have low 1,2,4,5-/1,2,3,4-Te MB values(less than 0.6),while oil samples originated mainly from terrestrial higher plants and source rocks deposited under oxic/sub-oxic conditions have higher 1,2,4,5-/1,2,3,4-Te MB values(greater than 1.0).The significant difference of 1,2,4,5-/1,2,3,4-Te MB values is controlled by 1,2,4,5-Te MB content.1,2,4,5-Te MB content in oils derived from source rocks deposited in oxidized sedimentary environment(greater than 1.0 mg/g whole oil)is higher than that in oils from source rocks deposited in reduced sedimentary environment(less than 1.0 mg/g whole oil).1,2,4,5-/1,2,3,4-Te MB ratio might not or slightly be affected by evaporative fractionation,biodegradation and thermal maturity.1,2,4,5-/1,2,3,4-Te MB ratio and 1,2,4,5-Te MB content can be used as supplementary parameter for the identification of sedimentary environment and organic matter *** should be noted that compared to the identification of organic matter sources,the 1,2,4,5-/1,2,3,4-Te MB parameter is more effective in identifying sedimentary environments.

关键词： 1 2 4 5-Tetramethylbenzene GC×GC-TOFMS Organic matter origin Depositional environment