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Superior Ductile and High-barrier Poly(lactic acid)Films by Constructing Oriented Nanocrystals as Efficient Reinforcement of Chain Entanglement Network and Promising Barrier Wall

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Chinese Journal of Polymer Science 2022年第10期40卷 1201-1212,I0009页

作者： Lin Zhou Ping-Ping Xu shi-hao ni Ling Xu hao Lin Gan-Ji Zhong Hua-Dong Huang Zhong-Ming Li Collge of Polymer Science and Engineering State Key Laboratory of Polymer Materials EngineeringSichuan UniversityChengdu 610065China

It is a daunting task to develop a promising strategy at an industrial scale for simultaneously ameliorating ductility and gas barrier performance of poly(lactic acid)(PLA)films in the application of green *** this work,biaxial stretching and constrained annealing were employed to prepare transparent PLA films with superior ductility and barrier *** oriented nano-sized crystals induced by biaxial stretching were developed into regularαform during constrained annealing,which could not only serve as“nano-barrier wall”to impede the diffusion and dissolution of gas molecules,but also strengthen amorphous chain entanglement network as physical crosslink to enhance *** a result,the as-prepared PLA films exhibited an outstanding comprehensive performance with a low oxygen and water vapor permeability coefficient of 0.733×10^(-14) cm^(3)·cm·cm^(-2)·s^(-1)·Pa^(-1) and 3.82×10^(-14) g·cm·cm^(-2)·s^(-1)·Pa^(-1),respectively,outstanding ductility with elongation at break of 66.0%,high yield strength of 84.2 MPa,and good transparency of more than 80%at 550 *** new insight in the relationship between microscopic amorphous and crystalline structure and macroscopic performance is conducive to alleviating the intrinsic defects of brittle and insufficient barrier PLA films without the aid of any heterogenous modifiers,facilitating their widespread commercialization in the booming sustainable packaging market.

关键词： Poly(lactic acid)films Biaxial stretching Constrained annealing Gas barrier properties Ductility

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A Knowledge-enhanced Two-stage Generative Framework for Medical Dialogue Information Extraction

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Machine Intelligence Research 2024年第1期21卷 153-168页

作者： Zefa Hu Ziyi ni Jing shi Shuang Xu Bo Xu School of Artificial Intelligence University of Chinese Academy of SciencesBeijing 100049China Institute of Automation Chinese Academy of SciencesBeijing 100190China

This paper focuses on term-status pair extraction from medical dialogues(MD-TSPE),which is essential in diagnosis dia-logue systems and the automatic scribe of electronic medical records(EMRs).In the past few years,works on MD-TSPE have attracted increasing research attention,especially after the remarkable progress made by generative ***,these generative methods output a whole sequence consisting of term-status pairs in one stage and ignore integrating prior knowledge,which demands a deeper un-derstanding to model the relationship between terms and infer the status of each *** paper presents a knowledge-enhanced two-stage generative framework(KTGF)to address the above *** task-specific prompts,we employ a single model to com-plete the MD-TSPE through two phases in a unified generative form:We generate all terms the first and then generate the status of each generated *** this way,the relationship between terms can be learned more effectively from the sequence containing only terms in the first phase,and our designed knowledge-enhanced prompt in the second phase can leverage the category and status candidates of the generated term for status ***,our proposed special status"not mentioned"makes more terms available and en-riches the training data in the second phase,which is critical in the low-resource *** experiments on the Chunyu and CMDD datasets show that the proposed method achieves superior results compared to the state-of-the-art models in the full training and low-re-sourcesettings.

关键词： Medical dialogue understanding information extraction text generation knowledge-enhanced prompt low-resource setting dataaugmentation

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Maps Preserving Semi-Fredholm Operators with Fixed Nullity

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Journal of Mathematical Research with Applications 2024年第4期44卷 533-540页

作者： Mengran ni Weijuan shi Department of Mathematics Shaanxi Normal University

Let X be an infinite-dimensional complex Banach space, and B(X) the algebra of all bounded linear operators on X. Given an integer n ≥ 1, we characterize all the bijective maps on B(X) preserving the difference of se... 详细信息

关键词： operator algebra adjacency preserver map semi-Fredholm operator

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Growth kinetics of titanium carbide coating by molten salt synthesis process on graphite sheet surface

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International Journal of Minerals,Metallurgy and Materials 2024年第8期31卷 1858-1864页

作者： Xiaoyu shi Chongxiao Guo Jiamiao ni Songsong Yao Liqiang Wang Yue Liu Tongxiang Fan State Key Lab of Metal Matrix Composites School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China

The synthesis of carbide coatings on graphite substrates using molten salt synthesis(MSS),has garnered significant interest due to its cost-effective *** study investigates the reaction process and growth kinetics involved in MSS,shedding light on key aspects of the *** involvement of Ti powder through liquid-phase mass transfer is revealed,where the diffusion distance and quantity of Ti powder play a crucial role in determining the reaction rate by influencing the C content gradient on both sides of the ***,the growth kinetics of the carbide coating are predominantly governed by the diffusion behavior of C within the carbide layer,rather than the chemical reaction *** analyze the kinetics,the thickness of the carbide layer is measured with respect to heat treatment time and temperature,unveiling a parabolic relationship within the temperature range of 700-1300℃.The estimated activation energy for the reaction is determined to be 179283 J·mol^(-1).These findings offer valuable insights into the synthesis of carbide coatings via MSS,facilitating their optimization and enhancing our understanding of their growth mechanisms and properties for various applications.

关键词： titanium carbide graphite molten salt kinetic analysis

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Exosomal microRNAs in hepatocellular carcinoma,expanding research field

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World Journal of Gastroenterology 2024年第20期30卷 2618-2620页

作者： Bo-hao Zheng Xiao-Jian ni Hou-Bao Liu Department of Biliary Surgery Zhongshan HospitalFudan UniversityShanghai 200032China Biliary Tract Disease Center of Zhongshan Hospital Fudan UniversityShanghai 200032China Biliary Tract Disease Institute Fudan UniversityShanghai 200032China Cancer Center Zhongshan HospitalFudan UniversityShanghai 200032China Shanghai Biliary Tract Minimal Invasive Surgery and Materials Engineering Research Center Shanghai 200032China

In this editorial we comment on the review by Wang et al published in the recent issue of the World Journal of Gastroenterology in *** extracellular vesicles(exosomes)play important roles in the tumor *** this review,the authors introduce the following points:(1)The composition and function of exosomal microRNAs(miRNAs)of different cell origins in hepatocellular carcinoma(HCC);(2)the crosstalk between exosomal miRNAs from stromal cells and immune cells in the tumor microenvironment and the progression of HCC;and(3)the potential applicability of exosomal miRNAs derived from mesenchymal stem cells in the treatment of *** addition,the potential applicability of exosomal miRNAs derived from mesenchymal stem cells in the treatment of HCC was *** this review,the authors give us an overview of the exosomal RNA and summarize the function of exosomal RNA in HCC,which provides a deeper understanding of exosomal miRNAs to the readers.

关键词： Exosomes MicroRNA Hepatocellular carcinoma Liver cancer Tumor microenvironment

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Hybrid perovskite shows temperature-dependent photoluminescence and dielectric response triggered by halogen substitution

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Chinese Journal of Structural Chemistry 2024年第6期43卷 28-33页

作者： Xiao-Tong Sun hao-Fei ni Yi Zhang Da-Wei Fu Ordered Matter Science Research Center Jiangsu Key Laboratory for Science and Applications of Molecular FerroelectricsSoutheast UniversityNanjing211189People's Republic of China Institute for Science and Applications of Molecular Ferroelectrics Key Laboratory of the Ministry of Education for Advanced Catalysis MaterialsZhejiang Normal UniversityJinhua321004People's Republic of China

Materials exhibiting dielectric switching response and photoluminescence(PL)are promising for sensors and information *** previous research,we synthesized a series of materials with red or green PL and dielectric switching capabilities by incorporating luminescent metal halides into organic ammonium ***,effective modification to synthesize organic-inorganic hybrid materials with dielectric switching response and orange PL continues to be a challenge in the respective *** PL materials are valuable for switching and sensors,and most orange light sources are derived from rare earth elements,making them harder to *** have successfully synthesized two organic-inorganic hybrid materials([CMPD]PbBr_(3)(1)and[BMPD]PbBr_(3)(2),CMPD=N-ClCH_(2)-N-methylpiperidine,BMPD=N-BrCH_(2)-N-methylpiperidine)that exhibit both orange PL and dielectric switching *** Cl in compound 1 is substituted by Br in compound 2,the phase transition temperature of the compound is elevated by 45 *** compounds exhibit captivating orange light emission when exposed to ultraviolet *** research provides insights into exploring multifunctional materials with orange PL and dielectric switching response and provides proof for halogen substitution strategies to design materials with higher phase transition temperatures.

关键词： Dielectric switching Photoluminescence Orange

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Effects of rafting on the meso deformation and fracture behaviour of a ni-based single crystal superalloy at room temperature: In-situ observation and simulation

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Science China(Technological Sciences) 2024年第7期67卷 2133-2146页

作者： TAN Long YANG XiaoGuang shi DuoQi FAN YongSheng shi Yi School of Energy and Power Engineering Beihang UniversityBeijing 102206China Research Institute of Aero-Engine Beihang UniversityBeijing 102206China National Key Laboratory of Science and Technology on Aero-Engine Aero-Thermodynamics Beihang UniversityBeijing 102206China School of Materials Science&Engineering Shanghai Jiao Tong UniversityShanghai 200240China

Microstructural rafting of ni-based single-crystal(SC) superalloys is inevitable at elevated temperatures during long-term service with mechanical loading, which significantly affects the mechanical behaviour of the material. In this study, the effects of rafting on the mesodeformation and fracture behaviour of a ni-based SC superalloy under cyclic and tensile loads were investigated using in situ scanning electron microscopy(SEM), digital image correlation(DIC), and crystal plasticity finite element method(CP-FEM) simulations. The results indicated that the tensile strength decreased significantly in the rafted specimens. In the cyclic tests, both the virgin and rafted specimens showed an increase in the maximum shear strain with cycle number. The interaction of cross-slip bands was captured by in situ SEM-DIC around the micro-notch of the virgin specimens during the tensile test, while a more homogeneous local deformation field was observed in the rafting specimens. In addition,the fracture behaviour was strongly influenced by the rafting morphology. The crack exhibited instantaneous and long-range fracture features along the octahedral plane as it propagated in the rafting specimen, whereas it deflected over a short distance between the crystallographic planes at an early stage in the virgin specimen, which is consistent with the CP-FEM ***, the CP-FEM results for the crack initiation direction on(111) dominant slip plane were consistent with the in situ SEM observations.

关键词： in-situ SEM-DIC ni-based SC superalloys microstructural rafting deformation crack path CP-FEM

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Formation of free-surface vortex and vortex suppression by rotating stopper-rod at end of tundish casting

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Journal of Iron and Steel Research International 2024年第5期31卷 1104-1116页

作者： Qing Fang Peng Zhao Hua Zhang Wen-hao Zhou Gang Yu Jia-hui Wang Hong-wei ni The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan430081HubeiChina Hunan Valin Xiangtan Iron and Steel Co. Ltd.Xiangtan411101HunanChina Hubei Provincial Key Laboratory for New Processes of Ironmaking and Steelmaking Wuhan University of Science and TechnologyWuhan430081HubeiChina

A rotating stopper-rod technique was proposed to suppress the formation of free-surface vortex in the *** large eddy simulation model coupled with volume of fluid model was developed to study the steel–slag–gas three-phase flow *** critical slag entrapment height of the free-surface vortex and mass of residual steel were predicted at different rotating speeds(30,60,90 and 120 r/min)of the rotating *** numerical model was verified by water model *** results showed that by rotating the stopper-rod in the opposite direction of the vortex above the submerged entry nozzle,the formation of vortex can be effectively disturbed and the critical height of the free-surface vortex can be *** for the 2nd strand,when the rotating speeds are 30,60,90 and 120 r/min,the critical height of the free-surface vortex above the 2nd strand is 7.3,4.7,6.3 and 7.4 cm,respectively.A reasonable rotating speed should be 60 r/min,which can reduce about 2 tons of residual *** rotating speeds just can reduce about 1.6 tons of residual steel.

关键词： Tundish Free-surface vortex Stopper-rod Numerical simulation Multiphase flow

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Amorphous electrocatalysts for urea oxidation reaction

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Progress in Natural Science:Materials International 2024年第2期34卷 362-375页

作者： Fenghui Guo Dongle Cheng Qian Chen hao Liu Zhiliang Wu ning Han Bing-Jie ni Zhijie Chen School of Materials Science and Technology China University of Geosciences Shenzhen Academy of Metrology and Quality Inspection Centre for Technology in Water and Wastewater School of Civil and Environmental Engineering University of Technology Sydney College of Safety and Environmental Engineering Shandong University of Science and Technology Institute of Yellow River Delta Earth Surface Processes and Ecological Integrity Shandong University of Science and Technology Discipline of Chemical Engineering Western Australian School of Mines: Minerals Energy and Chemical Engineering Curtin University Department of Materials Engineering School of Civil and Environmental Engineering The University of New South Wales

Electrochemical urea oxidation reaction(UOR) is a promising alternative to oxygen evolution reaction(OER) for realizing energy-saving hydrogen production. Developing efficient electrocatalysts for UOR becomes a central challenge. Recently, amorphous materials have been extensively used as UOR catalysts because of their numerous defective sites and flexible electronic properties. In this review, recent advancements in the development of amorphous UOR electrocatalysts are analyzed. The UOR mechanism is discussed, and the design of amorphous catalysts is then analyzed. The main catalyst design strategies are illustrated, including nanostructure control,heteroatom doping, composition regulation, and heterostructure construction. Also, electrocatalysts' structureperformance correlation is interpreted. Perspectives in this field are proposed for guiding future studies on the development of high-performance amorphous catalysts towards energy sustainability.

关键词： Catalyst design Component regulation Heteroatom doping Heterostructures Hydrogen energy

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Lift system optimization for hover-capable flapping wing micro air vehicle

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Frontiers of Mechanical Engineering 2024年第3期19卷 61-75页

作者： Shengjie XIAO Yongqi shi Zemin WANG Zhe ni Yuhang ZHENG Huichao DENG Xilun DING Department of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China Shenzhen International Graduate School Tsinghua UniversityShenzhen 518055China

A key challenge is using bionic mechanisms to enhance aerodynamic performance of hover-capable flapping wing micro air vehicle(FWMAV).This paper presented a new lift system with high lift and aerodynamic efficiency,which use a hummingbird as a bionic *** new lift system is able to effectively utilize the high lift mechanism of hummingbirds,and this study innovatively utilizes elastic energy storage elements and installs them at the wing root to help improve aerodynamic performance.A flapping angle of 154°is achieved through the optimization of the flapping mechanism *** optimized wing shape and parameters are obtained through experimental studies on the ***,the max net lift generated is 17.6%of the flapping wing vehicle’s ***,energy is stored and released periodically during the flapping cycle,by imitating the musculoskeletal system at the wing roots of hummingbirds,thereby improving the energy utilization rate of the FWMAV and reducing power consumption by 4.5%under the same ***,strength verification and modal analyses are conducted on the flapping mechanism,and the weight of the flapping mechanism is reduced through the analysis and testing of different *** results show that the lift system can generate a stable lift of 31.98 g with a wingspan of 175 mm,while the lift system weighs only 10.5 g,providing aerodynamic conditions suitable for high maneuverability flight of FWMAVs.

关键词： lift optimization flapping wing elastic energy hovering flapping mechanism

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