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Applied Mathematics and Mechanics(English Edition) 2023年第10期44卷 1761-1776页

作者： Changsong ZHU xueqian fang Jinxi LIU State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China Key Laboratory of Mechanical Behavior Evolution and Control of Traffic Engineering Structures in Hebei Shijiazhuang 050043China School of Environment and Civil Engineering Dongguan University of TechnologyDongguan 523808Guangdong ProvinceChina

In this paper, the nonlinear free vibration behaviors of the piezoelectric semiconductor(PS) doubly-curved shell resting on the Pasternak foundation are studied within the framework of the nonlinear drift-diffusion(NLDD) model and the first-order shear deformation theory. The nonlinear constitutive relations are presented, and the strain energy, kinetic energy, and virtual work of the PS doubly-curved shell are derived.Based on Hamilton's principle as well as the condition of charge continuity, the nonlinear governing equations are achieved, and then these equations are solved by means of an efficient iteration method. Several numerical examples are given to show the effect of the nonlinear drift current, elastic foundation parameters as well as geometric parameters on the nonlinear vibration frequency, and the damping characteristic of the PS doublycurved shell. The main innovations of the manuscript are that the difference between the linearized drift-diffusion(LDD) model and the NLDD model is revealed, and an effective method is proposed to select a proper initial electron concentration for the LDD model.

关键词： nonlinear free vibration piezoelectric semiconductor(PS)doubly-curved shell nonlinear drift-diffusion(NLDD)model linearized drift-diffusion(LDD)model

Multi-field coupling and free vibration of a sandwiched functionally-graded piezoelectric semiconductor plate

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Applied Mathematics and Mechanics(English Edition) 2023年第8期44卷 1351-1366页

作者： xueqian fang Qilin HE Hongwei MA Changsong ZHU School of Environment and Civil Engineering Dongguan University of TechnologyDongguan 523808Guangdong ProvinceChina Guangdong Provincial Key Laboratory of Intelligent Disaster Prevention and Emergency Technologies for Urban Lifeline Engineering Dongguan University of TechnologyDongguan 523808Guangdong ProvinceChina State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China

Sandwiched functionally-graded piezoelectric semiconductor(FGPS)plates possess high strength and excellent piezoelectric and semiconductor properties,and have significant potential applications in micro-electro-mechanical systems.The multi-field coupling and free vibration of a sandwiched FGPS plate are studied,and the governing equation and natural frequency are derived with the consideration of electron movement.The material properties in the functionally-graded layers are assumed to vary smoothly,and the first-order shear deformation theory is introduced to derive the multi-field coupling in the plate.The total strain energy of the plate is obtained,and the governing equations are presented by using Hamilton’s principle.By introducing the boundary conditions,the coupling physical fields are solved.In numerical examples,the natural frequencies of sandwiched FGPS plates under different geometrical and physical parameters are discussed.It is found that the initial electron density can be used to modulate the natural frequencies and vibrational displacement of sandwiched FGPS plates in the case of nano-size.The effects of the material properties of FGPS layers on the natural frequencies are also examined in detail.

关键词： sandwiched piezoelectric semiconductor(PS)plate functionally-graded layer multi-field coupling free vibration Hamilton's principle

SH Waves in(1-x)Pb(Mg_(1/3)Nb_(2/3))O_(3-x)PbTiO_3 Piezoelectric Layered Structures Loaded with Viscous Liquid

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Acta Mechanica Solida Sinica 2016年第5期29卷 479-489页

作者： Guoquan Nie Jinxi Liu Yanping Kong xueqian fang School of Mechanical Engineering Shijiazhuang Tiedao University Department of Engineering Mechanics Shijiazhuang Tiedao University

The velocity dispersion and attenuation of shear horizontal（SH） waves in a layered piezoelectric structure loaded with viscous liquid is studied,where the（1- x）Pb（Mg（1/3）Nb（2/3））O（3-x）PbTiO3[PMN-xPT]single crystal is chosen as the piezoelectric layer.The PMN-xPT is being polarized along[011]c and[001]c so that the macroscopic symmetries are mm 2 and 4 mm,respectively.For the nonconductive liquid,the electrically open and shorted conditions at the interface between the liquid and the piezoelectric layer are considered.The phase velocity equations are derived analytically.The effects of the electrically boundary condition,the viscous coefficient and mass density of liquid as well as the thickness of the PMN-xPT layer on the phase velocity and attenuation are graphically illustrated.The results show that the phase velocity for the[011]c polarized PMN-0.29 PT is much smaller than that for the[001]c polarized PMN-0.33 PT,and the effects of viscous coefficient and piezoelectric layer thickness on the phase velocity for the[011]c case are stronger than that for the[001]c case.In addition,the electrical boundary conditions have an obvious influence on the propagation behaviors.These results can be useful for the designs and applications of acoustic wave devices and liquid biosensors.

关键词： piezoelectric electrically biosensors attenuation layered viscous macroscopic loaded polarized illustrated

Dynamic behavior of bridge-erecting machine subjected to moving mass suspended by wire ropes

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Applied Mathematics and Mechanics(English Edition) 2016年第6期37卷 741-748页

作者： Shaopu YANG xueqian fang Jianchao ZHANG Dujuan WANG School of Mechanical Engineering Shijiazhuang Tiedao University China Railway Engineering Equipment Group Co. Ltd.

The dynamic behavior of a bridge-erecting machine, carrying a moving mass suspended by a wire rope, is investigated. The bridge-erecting machine is modelled by a simply supported uniform beam, and a massless equivalent ＂spring-damper＂ system with an effective spring constant and an effective damping coefficient is used to model the moving mass suspended by the wire rope. The suddenly applied load is represented by a unitary Dirac Delta function. With the expansion method, a simple closed-form solution for the equation of motion with the replaced spring-damper-mass system is formulated. The characters of the rope are included in the derivation of the differential equation of motion for the system. The numerical examples show that the effects of the damping coefficient and the spring constant of the rope on the deflection have significant variations with the loading frequency. The effects of the damping coefficient and the spring constant under different beam lengths are also examined. The obtained results validate the presented approach, and provide significant references in the design process of bridgeerecting machines.

关键词： bridge-erecting machine wire rope dynamic behavior equivalent ＂spring-damper＂ system

Dynamic effective elastic modulus of polymer matrix composites with dense piezoelectric nano-fibers considering surface/interface effect

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Science China(Physics,Mechanics & Astronomy) 2015年第1期58卷 125-132页

作者： fang xueqian HUANG MingJuan ZHU ZiTao LIU JinXi FENG WenJie Department of Engineering Mechanics Shijiazhuang Tiedao University School of Mathematics and Science Xiamen University

Based on effective field method,the dynamic effective elastic modulus of polymer matrix composites embedded with dense piezoelectric nano-fibers is obtained,and the interacting effect of piezoelectric surfaces/interfaces around the nano-fibers is considered.The multiple scattering effects of harmonic anti-plane shear waves between the piezoelectric nano-fibers with surface/interface are averaged by effective field method.To analyze the interacting results among the random nano-fibers,the problem of two typical piezoelectric nano-fibers is introduced by employing the addition theorem of Bessel functions.Through numerical calculations,the influence of the distance between the randomly distributed piezoelectric nano-fibers under different surface/interface parameters is analyzed.The effect of piezoelectric property of surface/interface on the effective shear modulus under different volume fractions is also examined.Comparison with the simplified cases is given to validate this dynamic electro-elastic model.

关键词：聚合物基复合材料有效弹性模量纳米纤维压电性能纤维表面界面效应随机分布贝塞尔函数

Efficient Perovskite Solar Cells Employing Low-temperature Thin Tin Dioxide Electron Selective Layers

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Efficient Perovskite Solar Cells Employing Low-temperature T...

Microbe-induced gene silencing explores interspecies RNAi and opens up possibilities of crop protection

第三届新型太阳能电池学术研讨会

作者： Liyu Wei Jinjin Zhao xueqian fang Peng Wang Zhenghao Liu Jinxi Liu School of Materials Science and Engineering Department of Mechanicsshijiazhuang Tiedao University

In perovskite solar cells,the simple planar structure is advantageous for large-scale manufacturing.To improve the performance and play great potential of the perovskite film devices,we demonstrated the structures wit... 详细信息

关键词： low-temperature SnO2 perovskite solar cell CH3NH3PbI3 TiO2

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Science China(Life Sciences) 2024年第3期67卷 626-628页

作者： Rongxiang fang State Key Laboratory of Plant Genomics Institute of MicrobiologyChinese Academy of Sciencesand National Plant Gene Research CenterBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China

In most eukaryotes, small RNA(sRNA)-mediated RNA silencing(or RNA interference, RNAi) is an evolutionarily conserved mechanism that regulates gene expression in a sequence-specific manner.Generally, s RNAs are produced by the RNase III enzymes Dicers and then incorporated into Argonaute(AGO) proteins to regulate gene expression by mRNA degradation.

关键词： protection conserved manner

Enhanced Photocurrent by Co-sensitization of ZnO with Dye and CuInSe Nanocrystals

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Enhanced Photocurrent by Co-sensitization of ZnO with Dye an...

Life forms affect beta-diversity patterns of larch forests in China

第二届新型太阳能电池学术研讨会

作者： Zhenghao Liu Jinjin Zhao Peng Wang Liyu Wei Jiangbin Zhang Huayan Si xueqian fang Deliang Ren Xianglin Liu School of Materials Science and Engineering Shijiazhuang Tiedao University

Quantum dot-sensitized solar cells(QDSSCs) are mainly focused on highly toxic cadmium and lead chalcogenides. In this sense, CuInS, Cu In Se, and Cu In Sex S(CIS) QDs are an attractive less-toxic alternative to Cd-or Pb-based QDs with high gap energy(1.5e V). ZnO nanocrystals with particle size of 20-30 nm were firstly synthesised by template-free method. With the addition of CuInSe QDs, the absorption spectra shows obvious red shift of the band edge, meanwhile, the band gap of ZnO@CIS nanocomposite is 2.12 eV. The best devices, fabricated with the ZnO film and ZnO@CIS nanocomposite film, as comparison, the ZnO@CIS photoanode, shows a power conversion efficiency η of 6.66%. The synthetic ZnO@CIS nanocomposite is an advanced material reported rarely. What is more, the proposed ZnO nanocrystals and ZnO@CIS nanocomposite synthesis methods are facile, simple and low-cost compared to other existed methods. The materials by these synthsis methods can be used in other solar cells such as Quantum Dot-sensitized Solar Cells and latest perovskite solar cells, even in other fields like photocatalysis, photodegradation, photoluminescence and so on.

关键词： ZnO nanocrystals template-free method QDSSCs

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Plant Diversity 2024年第1期46卷 49-58页

作者： Wenjing fang Qiong Cai Chengjun Ji Jiangling Zhu Zhiyao Tang Jingyun fang School of Ecology and Environmental Science Yunnan UniversityKunming 650091China Department of Ecology College of Urban and Environmental Sciencesand Key Laboratory for Earth Surface Processes of the Ministry of EducationPeking UniversityBeijing 100871China

Beta-diversity reflects the spatial changes in community species composition which helps to understand how communities are assembled and biodiversity is formed and maintained. Larch(Larix) forests, which are coniferous forests widely distributed in the mountainous and plateau areas in North and Southwest China, are critical for maintaining the environmental conditions and species diversity. Few studies of larch forests have examined the beta-diversity and its constituent components(species turnover and nestedness-resultant components). Here, we used 483 larch forest plots to determine the total betadiversity and its components in different life forms(i.e., tree, shrub, and herb) of larch forests in China and to evaluate the main drivers that underlie this beta-diversity. We found that total betadiversity of larch forests was mainly dependent on the species turnover component. In all life forms,total beta-diversity and the species turnover component increased with increasing geographic, elevational, current climatic, and paleoclimatic distances. In contrast, the nestedness-resultant component decreased across these same distances. Geographic and environmental factors explained 20%-25% of total beta-diversity, 18%-27% of species turnover component, and 4%-16% of nestedness-resultant component. Larch forest types significantly affected total beta-diversity and species turnover component. Taken together, our results indicate that life forms affect beta-diversity patterns of larch forests in China, and that beta-diversity is driven by both niche differentiation and dispersal limitation. Our findings help to greatly understand the mechanisms of community assemblies of larch forests in China.

关键词： Beta-diversity Species turnover Nestedness-resultant Geographic distance Climatic distance Larch forest

Pancreatic panniculitis as the first presentation of pancreatic ductaladenocarcinoma

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Hepatobiliary & Pancreatic Diseases International 2024年第1期23卷 106-108页

作者： Wei-fang Zhu Shan fang Jian-Jun Qiao Department of Dermatology the First Affiliated HospitalZhejiang University School of MedicineHangzhou 310003China

To the Editor:Pancreatic panniculitis,also known as pancreatic fat necrosis or enzymatic panniculitis,is a rare type of panniculitis that occurs in 0.3%−3%of patients with pancreatic disease such as acute or chronic pancreatitis and pancreatic carcinoma,especially acinar cell carcinoma[1,2].The clinical manifestations are nonspecific erythema tender nodules.

关键词： Pancreatic acute adenocarcinoma