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Realizing the purification and grain refinement of Mg-Gd-Y alloy by one-step flux refining

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Journal of Materials Science & Technology 2024年第6期173卷 202-217页

作者： xin tong Guohua Wu Ming sun Qiman wang Liang Zhang Wencai liu National Engineering Research Center of Light Alloy Net Forming and State Key Laboratory of Metal Matrix Composites School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China School of Materials and Chemistry University of Shanghai for Science and TechnologyShanghai 200093China

In the conventional melt preparation of magnesium rare-earth(Mg-RE)alloys,the repeated heating/cooling process involved in grain refinement and flux refining usually prolongs the preparation period and aggravates melt *** this work,the purification and grain refinement of Mg-9Gd-3Y(GW93)alloy was simultaneously realized by one-step refining at 740℃ by using a self-developed compound *** results show that,only after holding for 10 min,the inclusion content of the alloy is reduced by 81%to 0.29%,while the grain size is reduced by 84%to 119μm.A physical model depicting the interactions between compound flux and alloy melt was proposed based on thermodynamic calculation and microstructure *** grain refinement mechanism has been analyzed by considering the presence of Zr particle(Zr_(p))and Zr solute(Zr_(s)).In addition,the generated RECl_(3) was found to be readily absorbed by the flux,decreasing the surface tension and promoting the purification efficacy of the flux,which plays an important role in the promoted elongation of the as-cast Mg-9Gd-3Y-0.5Zr(GW93K)*** work presents a unique prospect in simplifying the melt preparation of Mg-RE alloy with a promoted quality.

关键词： Mg-Gd-Y-Zr alloy Purification Grain refinement Compound flux Settling behavior

Micro-sized nanoaggregates:Spray-drying-assisted fabrication and applications

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Particuology 2024年第2期85卷 22-48页

作者： dan-Lei Yang Rong-Kun liu Yan wei Qian sun Jie-xin wang School of Life Sciences and Chemical Engineering Jiangsu Second Normal UniversityNanjing210013China State Key Laboratory of Organic-Inorganic Composites Beijing University of Chemical TechnologyBeijing100029China Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology School of Chemistry and Chemical EngineeringGuangxi UniversityNanning530004China

The applications of nanoparticles suffer from their extremely small size and intrinsic trend of *** nanoparticles to form micro-sized nanoaggregates(MNAs)with increased size,ordered structure,as well as controllable size,shape,and morphology is a crucial step in various fields of science and technology to maintain the unique characteristics of nanoparticles while obtaining greatly enhanced or new performance at the *** structure of MNAs prominently affects their functionality,which is determined by the arrangement of nanoparticles and the interaction between primary *** methods have been proposed to prepare the MNAs,in which spray-drying technology stands out considering the feasibility,scalability for industry,cost,and *** assembly of nanoparticles through spray-drying under tunable process parameters yields diverse physical properties and structural arrangements of nanoparticles of the MNAs,they therefore exhibit enormous potential in a wide range of application *** review presents the construction and applications of spray-dried *** factors that influence the size,morphology,and structure of the MNAs are discussed in *** addition,the outstanding application performance resulting from the tightly packed nanoparticles in regular-shaped MNAs obtained by the spray-drying process is illustrated.

关键词： Spray-drying Micro-sized nanoaggregates Applications

Phase induced localization transition

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Chinese Physics B 2024年第10期33卷 362-365页

作者： tong liu xingbo wei Youguo wang School of Science Nanjing University of Posts and TelecommunicationsNanjing 210003China Department of Physics and Key Laboratory of Optical Field Manipulation of Zhejiang Province Zhejiang Sci-Tech UniversityHangzhou 310018China

Localization phenomenon is an important research field in condensed matter ***,due to the complexity and subtlety of disordered systems,new localization phenomena always emerge *** example,it is generally believed that the phase of the hopping term does not affect the localization properties of the system,so the calculation of the phase is often ignored in the study of ***,we introduce a quasiperiodic model and demonstrate that the phase change of the hopping term can significantly alter the localization properties of the system through detailed numerical simulations,such as the inverse participation ratio and multifractal *** phase-induced localization transition provides valuable information for the study of localization physics.

关键词： phase localization quasiperiodic

Economical Quadrupedal Multi-Gait Locomotion via Gait-Heuristic Reinforcement Learning

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Journal of Bionic Engineering 2024年第4期21卷 1720-1732页

作者： Lang wei Jinzhou Zou Xi Yu Liangyu liu Jianbin Liao wei wang tong Zhang School of Power and Mechanical Engineering Wuhan UniversityLuojiashanWuhan430072HubeiChina State Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan UniversityLuojiashanWuhan430072HubeiChina

In order to strike a balance between achieving desired velocities and minimizing energy consumption,legged animals have the ability to adopt the appropriate gait pattern and seamlessly transition to another if *** ability makes them more versatile and efficient when traversing natural terrains,and more suitable for long *** the same way,it is meaningful and important for quadruped robots to master this *** achieve this goal,we propose an effective gait-heuristic reinforcement learning framework in which multiple gait locomotion and smooth gait transitions automatically emerge to reach target velocities while minimizing energy *** incorporate a novel trajectory generator with explicit gait information as a memory mechanism into the deep reinforcement learning *** allows the quadruped robot to adopt reliable and distinct gait patterns while benefiting from a warm start provided by the trajectory ***,we investigate the key factors contributing to the emergence of multiple gait *** tested our framework on a closed-chain quadruped robot and demonstrated that the robot can change its gait patterns,such as standing,walking,and trotting,to adopt the most energy-efficient gait at a given ***,we deploy our learned controller to a quadruped robot and demonstrate the energy efficiency and robustness of our method.

关键词： Legged robots Deep reinforcement learning Central pattern generator Quadrupedal gait

Hyperbranched polymer hollow-fiber-composite membranes for pervaporation separation of aromatic/aliphatic hydrocarbon mixtures

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Chinese Journal of Chemical Engineering 2024年第5期69卷 13-22页

作者： tong liu Hao sun Xiangqiong wang Jie Li Zhanquan Zhang Pei Wu Naixin wang Quanfu An Beijing Key Laboratory for Green Catalysis and Separation Department of Chemical EngineeringCollege of Materials Science and EngineeringBeijing University of TechnologyBeijing 100124China Petrochemical Research Institute CNPCBeijing 102206China

The separation of aromatic/aliphatic hydrocarbon mixtures is crucial in the petrochemical *** is regarded as a promising approach for the separation of aromatic compounds from alkanes. Developing membrane materials with efficient separation performance is still the main task since the membrane should provide chemical stability, high permeation flux, and selectivity. In this study, the hyperbranched polymer(HBP) was deposited on the outer surface of a polyvinylidene fluoride(PVDF)hollow-fiber ultrafiltration membrane by a facile dip-coating method. The dip-coating rate, HBP concentration, and thermal cross-linking temperature were regulated to optimize the membrane *** obtained HBP/PVDF hollow-fiber-composite membrane had a good separation performance for aromatic/aliphatic hydrocarbon mixtures. For the 50%/50%(mass) toluene/n-heptane mixture, the permeation flux of optimized composite membranes could reach 1766 g·m^(-2)·h^(-1), with a separation factor of 4.1 at 60℃. Therefore, the HBP/PVDF hollow-fiber-composite membrane has great application prospects in the pervaporation separation of aromatic/aliphatic hydrocarbon mixtures.

关键词： Aromatic/aliphatic hydrocarbons Hyperbranched polymer Pervaporation Hollow fiber membrane Dip-coating

Machine learning solution for regional landslide susceptibility based on fault zone division strategy

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Journal of Mountain Science 2024年第5期21卷 1745-1760页

作者： wang Yunhao wang Luqi liu Songlin sun weixin liu Pengfei ZHU Lin YANG Wenyu GUO tong School of Civil Engineering Chongqing UniversityChongqing 400045China Key Laboratory of New Technology for Construction of Cities in Mountain Area Chongqing UniversityMinistry of EducationChongqing 400045China National Joint Engineering Research Center of Geohazards Prevention in the Reservoir Areas Chongqing UniversityChongqing 400045China Institute of Geological Environment Monitoring Chongqing 401147China Chongqing 205 Geological Team Chongqing 401121China

Landslide susceptibility assessment is an essential tool for disaster prevention and management. In areas with multiple fault zones, the impact of fault zone on slope stability cannot be disregarded. This study performed qualitative analysis of fault zones and proposed a zoning method to assess the landslide susceptibility in Chengkou County, Chongqing Municipality, China. The region within a distance of 1 km from the faults was designated as sub-zone A, while the remaining area was labeled as sub-zone B. To accomplish the assessment, a dataset comprising 388 historical landslides and 388 non-landslide points was used to train the random forest model. 10-fold cross-validation was utilized to select the training and testing datasets for the model. The results of the models were analyzed and discussed, with a focus on model performance and prediction uncertainty. By implementing the proposed division strategy based on fault zone, the accuracy, precision, recall, F-score, and AUC of both two sub-zones surpassed those of the whole region. In comparison to the results obtained for the whole region, sub-zone B exhibited an increase in AUC by 6.15%, while sub-zone A demonstrated a corresponding increase of 1.66%. Moreover, the results of 100 random realizations indicated that the division strategy has little effect on the prediction uncertainty. This study introduces a novel approach to enhance the prediction accuracy of the landslide susceptibility mapping model in areas with multiple fault zones.

关键词： Landslide susceptibility mapping Fault division strategy Random forest GIS

Opportunities and challenges of high-entropy materials in lithium-ion batteries

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Rare Metals 2024年第10期43卷 4884-4902页

作者： tong-Yue Xu Huai-wei Feng wei liu Yan wang Hong-He Zheng College of Energy&Jiangsu Key Laboratory of Advanced Negative Carbon Technologies& Collaborative Innovation Center of Suzhou Nano Science and TechnologySoochow University NARI Technology Co. Ltd.

Lithium-ion batteries(LIBs) currently occupy an important position in the energy storage market, and the development of advanced LIBs with higher energy density and power density, better cycle life and safety is a hot topic for both academia and industry. In recent years, high-entropy materials(HEMs) with complex stoichiometric ratios have attracted great attention in the field of LIBs due to their various promising functional properties. The adjustability and synergistic effects of multiple elements in HEMs make them possible to break through the bottleneck of traditional electrode materials and electrolytes, providing new opportunities for the development of high-performance LIBs. This article provides an overview of the opportunities and challenges of HEMs in LIBs, including cathodes, anodes and electrolytes. The progress of HEMs in LIBs is first summarized and analyzed, then the potential advantages and limitations of HEMs used in LIBs are concluded, finally some envisioned solutions are proposed to develop more advanced LIBs through HEMs.

关键词： Lithium-ion batteries

Continuous-wave operation of 1550 nm low-threshold triple-lattice photonic-crystal surface-emitting lasers

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Light(Science & Applications) 2024年第3期13卷 446-453页

作者： Ziye wang Xia liu Pinyao wang Huanyu Lu Bo Meng wei Zhang Lijie wang Yanjing wang Cunzhu tong State Key Laboratory of Luminescence and Applications Changchun Institute of OpticsFine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Central Research Institute Planning Dept 2012 LabsHuawei Technologies Company Ltd.Shenzhen 518129China

Benefitting from narrow beam divergence,photonic crystal surface-emitting lasers are expected to play an essential role in the ever-growing fields of optical communication and light detection and *** operating with 1.55μm wavelengths have attracted particular attention due to their minimum fiber loss and high eye-safe ***,high interband absorption significantly decreases their performance at this 1.55μm ***,stronger optical feedback is needed to reduce their threshold and thus improve the output *** this goal,photonic-crystal resonators with deep holes and high dielectric contrast are often ***,the relevant techniques for high-contrast photonic crystals inevitably complicate fabrication and reduce the final *** this paper,we demonstrate the first continuous-wave operation of 1.55μm photonic-crystal surface-emitting lasers by using a‘triple-lattice photonic-crystal resonator’,which superimposes three lattice point groups to increase the strength of in-plane optical *** this geometry,the in-plane 180°coupling can be enhanced threefold compared to the normal single-lattice *** theoretical and experimental investigations demonstrate the much lower threshold current density of this structure compared to‘single-lattice’and‘double-lattice’photonic-crystal resonators,verifying our design *** findings provide a new strategy for photonic crystal laser miniaturization,which is crucial for realizing their use in future high-speed applications.

关键词： resonator crystal lattice

Phase Engineering of MXene Derivatives Via Molecular Design for High-Rate Sodium-Ion Batteries

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Energy & Environmental Materials 2024年第05期7卷 126-134页

作者： Hui Zhang xingwu Zhai xin Cao Zhihao liu xinfeng Tang Zhihong Hu Hang wang Zhandong wang Yang Xu wei He wei Zheng Min Zhou Zheng Ming sun Hefei National Laboratory for Physical Sciences at the Microscale School of Chemistry and Materials Science University of Science and Technology of China School of Materials Science and Engineering Southeast University National Synchrotron Radiation Laboratory University of Science and Technology of China Department of Chemistry University College London School of Chemistry and Chemical Engineering Southeast University

Since 2019, research into MXene derivatives has seen a dramatic rise; further progress requires a rational design for specific functionality. Herein, through a molecular design by selecting suitable functional groups in the MXene coating, we have implemented the dual N doping of the derivatives,nitrogen-doped TiO2@nitrogen-doped carbon nanosheets （N-TiO2@NC）, to strike a balance between the active anatase TiO2at low temperatures, and carbon activation at high temperatures. The NH3reduction environment generated at 400℃as evidenced by the in situ pyrolysis SVUV-PIMS process is crucial for concurrent phase engineering. With both electrical conductivity and surface Na+availability, the N-TiO2@NC achieves higher interface capacitive-like sodium storage with long-term stability. More than100 mAh g-1is achieved at 2 A g-1after 5000 cycles. The proposed design may be extended to other MXenes and solidify the growing family of MXene derivatives for energy storage.

关键词： high-rate sodium-ion batteries molecular design MXene derivative phase engineering