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Collapse arrest in a two-dimensional Airy Gaussian beam and Airy Gaussian vortex beam in nonlocal nonlinear media

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Communications in Theoretical Physics 2022年第2期74卷 105-117页

作者： Ye Chen Lijuan ge Xinglin Wang Ming shen Department of Physics Shanghai UniversityShanghai 200444China School of Physical Science and Technology Suzhou University of Science and TechnologySuzhou 215009China Department of Applied Mathematics and Physics Anhui Polytechnic UniversityWuhu 241000China

Propagation dynamics of a two-dimensional Airy Gaussian beam and Airy Gaussian vortex beam are investigated numerically in local and nonlocal nonlinear *** self-healing and collapse of the beam crucially depend on the distribution factor b and the topological charge *** the aid of nonlocality,a stable Airy Gaussian beam and an Airy Gaussian vortex beam with larger amplitude can be obtained,which always collapse in local nonlinear *** the distribution factor b is large enough,the Airy Gaussian vortex beam will transfer into quasivortex solitons in nonlocal nonlinear media.

关键词： Airy Gaussian beam Airy Gaussian vortex beam nonlocal nonlinear media self-healing collapse arrest

An explicit formulation of the macroscopic strength criterion for porous media with pressure and Lode angle dependent matrix under axisymmetric loading

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Journal of Rock Mechanics and geotechnical Engineering 2021年第4期13卷 820-832页

作者： Jincheng Fan Laurence Brassart Wanqing shen Xiurun ge Institute of Deep Earth Sciences and Green Energy College of Civil and Transportation EngineeringShenzhen UniversityShenzhen518060China School of Naval Architecture Ocean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China Department of Engineering Science University of OxfordOxfordOX13PJUK Department of Materials Science and Engineering Monash UniversityClaytonVIC3800Australia Univ.Lille CNRSCentrale LilleUMR 9013-LaMcube-Laboratoire de MecaniqueMultiphysiqueMulti-echelle59000LilleFrance

This paper aims to propose an explicit formulation of the macroscopic strength criterion for porous media with spherical *** matrix is assumed rigid and perfectly plastic with yield surface described by the three-parameter strength criterion,which is Lode angle and pressure dependent and capable of accounting for distinct values of the uniaxial tensile strength,uniaxial compressive strength(UCS)and equal biaxial compressive strength(eBCS).An exact upper bound of the macroscopic strength is derived for porous media subjected to purely hydrostatic ***,an estimate of the macroscopic strength profile of porous media under axisymmetric loading is obtained in parametric ***,a heuristic strength criterion in explicit form is further developed by examining limit cases of the parametric strength *** developed strength criteria are assessed by finite-element based numerical *** with the parametric strength criterion which involves cumbersome functions,the heuristic one is convenient for practical *** specific values of the matrix’s strength surface,the proposed heuristic strength criterion can recover the well-known Gurson *** present work also addresses the effect of the ratio of matrix’s eBCS to UCS on the macroscopic strength of porous *** matrix with distinct values of eBCS and UCS,neglecting the difference between eBCS and UCS would result in an underestimation of the macroscopic strength,especially when the pressure is large.

关键词： Porous materials Unified strength criterion Homogenization Gurson criterion

Liquid Crystalline Polymers

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Chinese Journal of Polymer Science 2022年第2期40卷 121-123页

作者： zhi-Hao shen Qi-Feng Zhou Peking University

History of Liquid Crystalline PolymersThe liquid crystalline(LC)state was first observed by Austrian botanist and chemist *** more than a century ago,and it was then confirmed in 1888 by german physicist *** who named such a state of matter as"liquid crystal"in *** low molecular mass(LMM)liquid crystals were successfully used in LC displays(LCDs),the development of LC polymers(LCPs)followed an independent ***,LCPs are prepared with the incorporation of mesogenic groups that are responsible for the formation of LC mesophases,such as rod-like(calamitic)and discotic ones,into polymer *** on where the mesogens are attached,traditionally there are three major categories of ***-chain LCPs(MCLCPs)have mesogens in the polymer backbone,while mesogens of side-chain LCPs(SCLCPs)are incorporated as side groups in a polymer with a relatively flexible main *** main-chain/side-chain combined LCPs(MCSCLCPs),mesogens are in both the backbone and side *** classes of LCPs include mesogenjacketed LCPs(MJLCPs),dendronized LCPs,and LC networks(LCNs).

关键词： backbone chains Crystalline

Effects of the types of overlap on the mechanical properties of FSSW welded AZ series magnesium alloy joints

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International Journal of Minerals,Metallurgy and Materials 2012年第3期19卷 231-235页

作者： Dan Wang Jun shen Lin-zhi Wang School of Materials Science and Engineering Chongqing UniversityChongqing 400044China

The effects of the types of overlap on the mechanical properties of the friction stir spot welding （FSSW） welded AZ series magnesium alloy joints were investigated by microstructural observations, microhardness tests, and tensile tests. The results show that the microstructure of the stir zone adjacent to the periphery of the rotating pin is mainly composed of the upper sheet. The average distance D between the longitudinal segment of the curved interface and the keyhole periphery, the tensile shear force, and the microhardness of the stir zone of the FSSW welded AZ61 alloy joint are the highest in all samples. During FSSW of AZ31 and AZ61 dissimilar magnesium alloys, the irregular deformation of the longitudinal segment of the curved interface appears, while the microhardness of the stir zone is higher when AZ61 alloy is the upper sheet. Moreover, the microhardness of the stir zone increases initially and then decreases sharply in the longitudinal test position.

关键词： magnesium alloys friction stir welding microstructure microhardness tensile properties

LSTM-based argument recommendation for non-API methods

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Science China(Information Sciences) 2020年第9期63卷 5-26页

作者： Guangjie LI Hui LIU ge LI Sijie shen Hanlin TANG School of Computer Science and Technology Beijing Institute of Technology School of Electronics Engineering and Computer Science Peking University

Automatic code completion is one of the most useful features provided by advanced IDEs. Argument recommendation, as a special kind of code completion, is widely used as well. While existing approaches focus on argument recommendation for popular APIs, a large number of non-API invocations are requesting for accurate argument recommendation as well. To this end, we propose an LSTM-based approach to recommending non-API arguments instantly when method calls are typed in. With data collected from a large corpus of open-source applications, we train an LSTM neural network to recommend actual arguments based on identifiers of the invoked method, the corresponding formal parameter, and a list of syntactically correct candidate arguments. To feed these identifiers into the LSTM neural network, we convert them into fixed-length vectors by Paragraph Vector, an unsupervised neural network based learning algorithm. With the resulting LSTM neural network trained on sample applications, for a given call site we can predict which of the candidate arguments is more likely to be the correct one. We evaluate the proposed approach with tenfold validation on 85 open-source C applications. Results suggest that the proposed approach outperforms the state-of-the-art approaches in recommending non-API arguments. It improves the precision significantly from 71.46% to 83.37%.

关键词： argument recommendation LSTM deep learning non-API

Altering the Hierarchical Morphology Distribution of Injection Molded Polyethylene by the Introduction of Crosslink Network and Periodical Shear

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Chinese Journal of Polymer Science 2016年第12期34卷 1479-1489页

作者： zhi-hao Zhao Fei-fei Wang Man Zhou Kai-zhi shen 张杰 College of Polymer Science and Engineer'ing State Key Laboratory of Polymer Materials En~neeringSichuan UniversityChengdu 610065China

High density polyethylene （HDPE） with moderate content of crosslink network （CPE） was successfully prepared through chemical method. Specimens for structural characterization have been molded by conventional injection molding （CIM） and pressure vibration injection molding （PVIM）. Influence of crosslink network on hierarchical morphology distribution and mechanical properties was systematically studied. Polarized light microscopy （PLM） revealed that both CIM and PVIM PE samples have a typical ＂skin-core＂ structure and the thickness of shear layer of CIM PE and PVIM CPE samples obviously increase. Scanning electron microscopy （SEM） showed that shish-kebab structures are clearly observed in shear layer of CIM CPE sample, indicating that the crosslink network can surely improve the formation of shish-kebab structures. Moreover, we suppose that shish-kebab structures emerged in shear and core layer of PVIM CPE sample. Wide- angle X-ray diffraction （WAXD） and small-angle X-ray scattering （SAXS） confirmed that more orientation and shish-kebab structures form even in core layer of PVIM CPE sample, which demonstrated that the hierarchical morphology was apparently altered by periodical shear and crosslink network. Finally, the mechanical properties revealed that this oriented structure increase the tensile strength from 31 MPa of CIM PE sample to 46 MPa of PVIM CPE sample. However, the tensile behavior tended to change from ductile fracture to brittle fracture.

关键词： Shish-kebab Morphology distribution Periodical shear Mechanical properties.

A direct polymeric carbon nitride/tungsten oxide Z-scheme heterostructure for efficient photocatalytic hydrogen generation via reforming of plastics into value-added chemicals

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Rare Metals 2024年第8期43卷 3771-3783页

作者： Rui-Zhe Wang zhi Lin Yi-Qing Wang Kai-Ni Zhang ge-Hong Zhang Jie Zhang Samuel S.Mao Shao-Hua shen International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi'an Jiaotong UniversityXi'an 710049China School of Civil and Architecture Engineering Xi'an Technological UniversityXi'an 710021China Department of Mechanical Engineering University of California at BerkeleyBerkeleyCA94720USA

To promote charge transfer and separation for efficient photocatalysis,a direct Z-scheme heterostructure was constructed by coupling polymeric carbon nitride(PCN) and WO_(3).Interestingly,the obtained PCN/WO_(3)Z-scheme heterostructure could photocataly tic ally produce hydrogen and value-added chemicals(e.g.,formate and acetate) by reforming of plastic polylactic acid(PLA) in alkaline aqueous *** optimizing WO_(3) contents and reaction conditions,the obtained PCN/WO_(3)heterostructure exhibits much increased photocatalytic activity for PLA photoreforming under visible light,with hydrogen evolution rate reaching 402.90 μmol·g~(-1)·h~(-1),which is 3.5 times that of *** is revealed that the Z-scheme charge transfer between PCN and WO_(3) mainly contributes to the promoted charge separation and thus the improved photocatalytic ***,with h+and·OH experimentally evidenced as the predominant active species,a possible reaction pathway for the reforming of PLA into value-added chemicals(e.g.,formate and acetate)over PCN/WO_(3) Z-scheme heterostructure is cleared by monitoring the reaction intermediates and *** work paves a carbon neutrality and scalable route toward the synergistical production of hydrogen and value-added chemicals by utilizing and recycling plastic waste.

关键词： Carbon nitride Z-scheme heterojunction Plastic waste conversion Photocatalytic H_(2)production Value-added chemicals

Preparation and Structure-Property Regulation Mechanism of Reversible Thermochromic Polydiacetylene

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Chinese Journal of Polymer Science 2024年第8期42卷 1111-1121页

作者： zhi-Qing ge Shuo Yan Zu-Xiong Pan Shan Lei Xuan-zhi Mao Chu Zhao Mo-Zhen Wang Xue-Wu ge Key Laboratory of Precision and Intelligent Chemistry Department of Polymer Science and EngineeringUniversity of Science and Technology of ChinaHefei 230026China Marshall Laboratory of Biomedical Engineering International Cancer CenterLaboratory of Evolutionary Theranostics(LET)School of Biomedical EngineeringShenzhen University Medical SchoolShenzhen UniversityShenzhen 518055China Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China University of Chinese Academy of Sciences Beijing 100049China

The thermochromic mechanism and the structure-property regulation principle of reversible thermochromic polydiacetylene(PDA)materials have always been a challenging *** this work,a series of diacetylene monomers(m-PCDA)containing phenyl and amide or carboxyl groups were synthesized from 10,12-pentacosadiynoic acid(PCDA)through the esterification or amidation *** effects of the number and the distribution of the functional groups in m-PCDA molecules on their solid-state polymerization capability,and the thermochromic mechanism of their corresponding polymers(m-PDA)were investigated and discussed in *** results show that the m-PCDA monomers containing both benzene ring and groups that can form hydrogen bonding interactions have strong intermolecular interaction,and are easy to carry out the solid phase polymerization under 254-nm UV irradiation to obtain the corresponding new thermochromic m-PDA *** thermochromic behavior of m-PDA depends on its melting *** initial color-change temperature(blue to red)is determined by the onset melting tem perature,and the temperature range in which reversible color recovery can be achieved by repeat heating-cooling treatment is determined by its melting *** to the proposed thermochromic mechanism of PDA,various new PDA materials with precise thermochromic temperatu res and reversible thermochromic temperature ra nges can be designed and synthesized through the appropriate introduction of benzene ring and groups that can form hydrogen bonding interactions into the molecular structure of linear diacetylene *** work provides a perspective to the precise molecular structure design and the property regulation of the reversible thermochromic PDA materials.

关键词： Polydiacetylene Thermochromism Hydrogen bonding Chemical modification

An integrated pipeline model for biomedical entity alignment

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Frontiers of Computer Science 2021年第3期15卷 81-95页

作者： Yu HU Tiezheng NIE Derong shen Yue KOU ge YU School of Computer Science and Engineering Northeastern UniversityShenyang 110819China

Biomedical entity alignment,composed of two subtasks:entity identification and entity-concept mapping,is of great research value in biomedical text mining while these techniques are widely used for name entity standardization,information retrieval,knowledge acquisition and ontology *** works made many efforts on feature engineering to employ feature-based models for entity identification and ***,the models depended on subjective feature selection may suffer error propagation and are not able to uti-lize the hidden *** rapid development in health-related research,researchers need an effective method to explore the large amount of available biomedical ***,we propose a two-stage entity alignment process,biomedical entity exploring model,to identify biomedical entities and align them to the knowledge base *** model aims to automatically obtain semantic information for extracting biomedical entities and mining semantic relations through the standard biomedical knowledge *** experiments show that the proposed method achieves better performance on entity *** proposed model dramatically improves the FI scores of the task by about 4.5%in entity identification and 2.5%in entity-concept mapping.

关键词： entity alignment biomedical text mining neural network model