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Two-phase nonlocal integral models with a bi-Helmholtz averaging kernel for nanorods

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Applied Mathematics and Mechanics(English Edition) 2021年第10期42卷 1379-1396页

作者： pei zhang Hai QING State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China

In this work,the static tensile and free vibration of nanorods are studied via both the strain-driven(Strain D)and stress-driven(Stress D)two-phase nonlocal models with a bi-Helmholtz averaging *** adjusting the limits of integration,the integral constitutive equation of the Fredholm type is converted to that of the Volterra type and then solved directly via the Laplace transform *** unknown constants can be uniquely determined through the standard boundary conditions and two constrained conditions accompanying the Laplace transform *** the numerical examples,the bi-Helmholtz kernel-based Strain D(or Stress D)two-phase model shows consistently softening(or stiffening)effects on both the tension and the free vibration of nanorods with different boundary *** effects of the two nonlocal parameters of the bi-Helmholtz kernel-based two-phase nonlocal models are studied and compared with those of the Helmholtz kernel-based models.

关键词： two-phase nonlocal integral model bi-Helmholtz kernel tensile analysis free vibration exact solution Laplace transform

Synthesis and Characterization of Microcapsules with Chlorpyrifos Cores and Polyurea Walls

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Chemical Research in Chinese Universities 2006年第3期22卷 379-382页

作者： zhang Qiang zhang pei-pei JIAO Qing-ze College of Science Beijing Institute of Technology Beijing 100081 P. R. China College of Chemistry and Environmental Science Beijing Institute of Technology Beijing 100081 P. R. China

Microcapsules with chlorpyrifos cores and polyurea walls were synthesized with 2,4-tolylene diisocyanate as an oil-soluble monomer and ethylenediamine as a water-soluble monomer via an interracial polycondensation reaction. The products were characterized by means of Fourier transform infrared spectrometry, ^13C NMR spectrometry and ^31p NMR spectrometry. The morphology, the particle size and the particle size distribution, and the thermal properties were also evaluated. The prepared microcapsules exhibit clear and smooth surfaces and have a mean diameter of 28. 13 μm. These microcapsules also have a good thermal stability for long-term use, and have potential applications in minimizing the toxicity of chlorpyrifos through controlled release.

关键词： Microcapsule Chlorpyrifos Polyurea Synthesis Characterization

Fuzzy Support Vector Machine Based on Color Modeling for Facial Complexion Recognition in Traditional Chinese Medicine

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Chinese Journal of Electronics 2016年第3期25卷 474-480页

作者： zhang Jing zhang pei ZHUO Li Signal and Information Processing Laboratory Beijing University of Technology

Face diagnosis is one of the four diagnostic methods in Traditional chinese medicine(TCM). The morbidity of the organs can be revealed from the facial complexion. Due to the ambiguity of face diagnosis in TCM,Fuzzy support vector machine(FSVM) is utilized to remove the influence of outliers. The facial complexion recognition in TCM based on FSVM is proposed in this paper,which includes the following steps: 1) The facial cheek region are segmented as skin blocks; 2) The color feature in Lab color space is extracted from skin block to represent facial complexion characteristic; 3) The fuzzy membership is calculated to obtain the membership of the training samples, in which the final membership of training samples is determined by combining membership calculation based on distance with the facial complexion recognition based on color modeling; 4) The FSVM is built to classify facial complexion characteristic. Experimental results show that proposed facial complexion recognition has better antiinterference performance as well as a higher recognition rate up to 82%.

关键词： Traditional chinese medicine(TCM) Facial complexion recognition Fuzzy support vector machine(FSVM) Color modeling Fuzzy membership

CircRNA: a rising star in plant biology

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Journal of Genetics and Genomics 2022年第12期49卷 1081-1092页

作者： pei zhang Mingqiu Dai National Key Laboratory of Crop Genetic Improvement Huazhong Agricultural UniversityWuhanHubei 430070China

Circular RNAs(circRNAs) are covalently closed single-stranded RNA molecules, which are widespread in eukaryotic cells. As regulatory molecules, circRNAs have various functions, such as regulating gene expression, binding mi RNAs or proteins, and being translated into proteins, which are important for cell proliferation and cell differentiation, individual growth and development, as well as many other biological processes. However, compared with that in animal models, studies of circRNAs in plants lags behind and,particularly, the regulatory mechanisms of biogenesis and molecular functions of plant circRNAs remain elusive. Recent studies have shown that circRNAs are wide spread in plants with tissue-or developmentspecific expression patterns and are responsive to a variety of environmental stresses. In this review, we summarize these advances, focusing on the regulatory mechanisms of biogenesis, molecular and biological functions of circRNAs, and the methods for investigating circRNAs. We also discuss the challenges and the prospects of plant circ RNA studies.

关键词： Plant circRNA circRNA biogenesis circRNA regulation Roles of circRNA Methodologies in circRNA studies

Effect of vanadium content on hydrogen storage property in Ti-V-Cr alloys

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Rare Metals 2006年第Z1期25卷 374-377页

作者： SONG Xiping pei pei zhang peilong CHEN Guoliang State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083 China State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083 China State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083 China State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083 China

The effect of vanadium content on the microstructure and hydrogen absorption/desorption properties in Ti-V-Cr alloys was studied. The results show that with the increase of vanadium content from 5at.%, 10at.% to 35at.%, the hydrogen absorption capacity increases gradually from 1.14wt.%, 1.57wt.% to 2.84wt.%, and the hydrogen desorption capacity also increase from 0.43, 0.64, to 1.59. This indicates that the alloy with 35at.% vanadium content has the most optimum hydrogen storage capacity among these alloys. The microstructure observation also indicates that the alloy with 35at.% vanadium turns to be the single-phase alloy of the BCC solid solution. Furthermore, with the increase of vanadium content the pressure plateau becomes more distinguishing and shifts to lower pressure level gradually. The kinetics of hydrogen absorption was also found to be dependent with the vanadium content in these discussed alloys.

关键词： hydrogen storage alloy vanadium kinetics

Investigation on the automatic parameters extraction of pulse signals based on wavelet transform

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第8期8卷 1283-1289页

作者： WANG Hui-yan zhang pei-yong College of Computer Science ＆ Information Engineering Zhejiang Gongshang University Hangzhou 310018 China Institute of VLSI Design Zhejiang University Hangzhou 310027 China

This paper analyses a key problem in the quantification of pulse diagnosis. Due to the subjectivity and fuzziness of pulse diagnosis,quantitative methods are needed. To extract the parameters of pulse signals,the prerequisite is to detect the corners of pulse signals correctly. Up to now,the pulse parameters are mostly acquired by marking the pulse corners manually,which is an obstacle to modernize pulse diagnosis. Therefore,a new automatic parameters extraction approach for pulse signals using wavelet transform is presented. The results testified that the method we proposed is feasible and effective and can detect corners of pulse signals accurately,which can be expected to facilitate the modernization of pulse diagnosis.

关键词： Pulse signal Feature extraction Complex wavelet transform Quantitative diagnosis

Unified two-phase nonlocal formulation for vibration of functionally graded beams resting on nonlocal viscoelastic Winkler-Pasternak foundation

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Applied Mathematics and Mechanics(English Edition) 2023年第1期44卷 89-108页

作者： pei zhang P.SCHIAVONE Hai QING State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China Department of Mechanical Engineering University of AlbertaEdmontonAlberta T6G 1H9Canada

A nonlocal study of the vibration responses of functionally graded(FG)beams supported by a viscoelastic Winkler-Pasternak foundation is *** damping responses of both the Winkler and Pasternak layers of the foundation are considered in the formulation,which were not considered in most literature on this subject,and the bending deformation of the beams and the elastic and damping responses of the foundation as nonlocal by uniting the equivalently differential formulation of well-posed strain-driven(ε-D)and stress-driven(σ-D)two-phase local/nonlocal integral models with constitutive constraints are comprehensively considered,which can address both the stiffness softening and toughing effects due to scale *** generalized differential quadrature method(GDQM)is used to solve the complex eigenvalue *** verifying the solution procedure,a series of benchmark results for the vibration frequency of different bounded FG beams supported by the foundation are ***,the effects of the nonlocality of the foundation on the undamped/damping vibration frequency of the beams are examined.

关键词： two-phase nonlocal elasticity damping vibration functionally graded(FG)beam nonlocal viscoelastic Winkler-Pasternak foundation generalized differential quadrature method(GDQM)

Dynamic stability analysis of porous functionally graded beams under hygro-thermal loading using nonlocal strain gradient integral model

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Applied Mathematics and Mechanics(English Edition) 2023年第12期44卷 2071-2092页

作者： pei zhang P.SCHIAVONE Hai QING School of Science Xi’an University of Architecture and TechnologyXi’an 710055China Department of Mechanical Engineering University of AlbertaEdmonton T6G 1H9AlbertaCanada State Key Laboratory of Mechanics and Control for Aerospace Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China

We present a study on the dynamic stability of porous functionally graded(PFG)beams under hygro-thermal *** variations of the properties of the beams across the beam thicknesses are described by the power-law *** most studies on this topic,we consider both the bending deformation of the beams and the hygro-thermal load as size-dependent,simultaneously,by adopting the equivalent differential forms of the well-posed nonlocal strain gradient integral theory(NSGIT)which are strictly equipped with a set of constitutive boundary conditions(CBCs),and through which both the stiffness-hardening and stiffness-softening effects of the structures can be observed with the length-scale parameters *** the variables presented in the differential problem formulation are *** numerical solution of the dynamic instability region(DIR)of various bounded beams is then developed via the generalized differential quadrature method(GDQM).After verifying the present formulation and results,we examine the effects of different parameters such as the nonlocal/gradient length-scale parameters,the static force factor,the functionally graded(FG)parameter,and the porosity parameter on the ***,the influence of considering the size-dependent hygro-thermal load is also presented.

关键词： nonlocal strain gradient integral model dynamic stability porous functionally graded(PFG)shear deformation beam size-dependent hygro-thermal load generalized differential quadrature method(GDQM)

MD-AVB: A Multi-Manifold Based Available Bandwidth Prediction Algorithm

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Tsinghua Science and Technology 2020年第1期25卷 140-148页

作者： pei zhang Changqing An Zhanfeng Wang Fengyuan Ma Institute of Network Technology Beijing University of Posts and TelecommunicationsBeijing 100876China Institute for Network Sciences and Cyberspace Tsinghua UniversityBeijing 100084China School of Computer Science and Engineering Southeast UniversityNanjing 211189China

The performance of Internet applications is heavily affected by the end-to-end available bandwidth. Thus,it is very important to examine how to accurately predict the available Internet bandwidth. A number of available bandwidth prediction algorithms have been proposed to date, but none of the existing solutions are able to achieve a high level of accuracy. In this paper, a Multi-manifold based Available Bandwidth prediction algorithm(MD-AVB)is proposed, based on the observation that the available bandwidth space on the Internet is multi-manifold and asymmetrical. In the proposed algorithm, the available bandwidth space is divided into multiple lower-dimensional domains iteratively, and each domain is embedded separately to predict the available bandwidth. Experiments on HP S^3 datasets demonstrate that the proposed algorithm is more accurate than existing approaches.

关键词： available bandwidth space performance prediction multi-manifold asymmetry