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Computer Modeling in Engineering & Sciences 2022年第1期130卷 513-542页

作者： xuan peng Haojie Lian Department of Mechanical Engineering Suzhou University of Science and TechnologySuzhou215009China Key Laboratory of In-situ Property-improving Mining of Ministry of Education Taiyuan University of TechnologyTaiyuan030024China

This work presents some numerical aspects of isogeometric boundary element methods(IGABEM).The behavior of hyper-singular and nearly-singular integration is first explored on the distorted NURBS *** numerical treatments are proposed to enhance the quadrature in the framework of isogeometric *** a numerical implementation of IGABEM on the trimmed NURBS is *** on this idea,the surface crack problem is modeled incorporation with the phantom element *** proposed method allows the crack to intersect with the boundary of the body while preserving the original parametrization of the NURBS-based CAD geometry.

关键词： Isogeometric analysis trimmed NURBS singular integration boundary element method surface crack

An Isogeometric Cloth Simulation Based on Fast Projection Method

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Computer Modeling in Engineering & Sciences 2023年第3期134卷 1837-1853页

作者： xuan peng Chao Zheng Department of Mechanical Engineering Suzhou University of Science and TechnologySuzhou215009China Simshow High Technology Co. Ltd.Chengdu610042China Department of Mechanical and Industrial Engineering The University of IowaIowa CityIA 52242-1527USA

A novel continuum-based fast projection scheme is proposed for cloth *** geometry is described by NURBS,and the dynamic response is modeled by a displacement-only Kirchhoff-Love shell element formulated directly on NURBS *** fast projection method,which solves strain limiting as a constrained Lagrange problem,is extended to the continuum *** examples are studied to demonstrate the performance of the current *** proposed approach can be applied to grids of arbitrary topology and can eliminate unrealistic over-stretching efficiently if compared to spring-based methodologies.

关键词： Cloth simulation isogeometric analysis strain limiting fast projection

Dual-quaternion-based modeling and control for motion tracking of a tumbling target

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Journal of Systems Engineering and Electronics 2019年第5期30卷 985-994页

作者： peng xuan SHI Xiaoping GONG Yupeng Control and Simulation Center Harbin Institute of TechnologyHarbin 150001China Research Center of Satellite Technology Harbin Institute of TechnologyHarbin 150001China

This paper investigates the problem of controlling a chasing spacecraft(chaser)to track and rendezvous with an uncontrolled *** on the actual situation,the torque-free motion of an axisymmetric prolate rigid body is employed to represent the short-term attitude motion of the tumbling *** taking advantage of the dual quaternion’s compact and efficient description of the general rigid motion,the coupled and integrated model of the 6-degree-of-freedom(6-DOF)relative motion between the chaser and the tumbling target is derived in the chaser’s body fixed frame after taking full consideration of coordinate *** on the logarithm of dual quaternion,a sliding mode control(SMC)law based on the exponential reaching law and the continuous relay function is brought forward to address the problem of synchronization control of the 6-DOF relative *** results illustrate the effectiveness of the proposed method.

关键词： tumbling target dual-quaternion coupled dynamics relative motion

Integrated modeling of spacecraft relative motion dynamics using dual quaternion

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Journal of Systems Engineering and Electronics 2018年第2期29卷 367-377页

作者： peng xuan SHI Xiaoping GONG Yupeng Control and Simulation Center Harbin Institute of Technology Research Center of Satellite Technology Harbin Institute of Technology

To realize high accurate control of relative position and attitude between two spacecrafts, the coupling between position and attitude must be fully considered and a more precise model should be established. This paper breaks the traditional divide and conquer idea, and uses a mathematical tool, namely dual quaternion to establish the integrated 6 degree-of-freedom(6-DOF) model of relative position and attitude, which describes the coupled relative motion in a compact and efficient form and needs less information of the target. Considering the complex operation rules and the unclarity of the current relative motion model in dual quaternion, necessary mathematical foundations are given at first, followed by clear and detailed modeling process and analysis. Finally a generalized proportion-derivative(PD) controller law is designed. The simulation results show that based on the integrated model established by dual quaternion, this control law can achieve a high control accuracy of relative motion.

关键词： relative motion dual quaternion position and attitude coupling integrated modeling

;unctional metabolomics： from biomarker ：liscovery to metabolome reprogramming

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Protein & Cell 2015年第9期6卷 628-637页

作者： Bo peng Hui Li xuan-Xian peng Center for Proteomics and Metabolomics State Key Laboratory of Biocontrol School of Life Sciences MOE Key Lab Aquat Food Safety School of Life Sciences Sun Yat-sen University Guangzhou 510275 China Molecular Foundry Lawrence Berkeley National Laboratory Berkeley CA 94720 USA

Metabolomics is emerging as a powerful tool for studying metabolic processes, identifying crucial biomarkers responsible for metabolic characteristics and revealing metabolic mechanisms, which construct the content of discovery metabolomics. The crucial biomarkers can be used to reprogram a metabolome, leading to an aimed metabolic strategy to cope with alteration of internal and external environments, naming reprogramming metabo- Iomics here. The striking feature on the similarity of the basic metabolic pathways and components among vastly different species makes the reprogramming metabolomics possible when the engineered metabolites play biological roles in cellular activity as a substrate of enzymes and a regulator to other molecules including proteins. The reprogramming metabolomics approach can be used to clarify metabolic mechanisms of responding to changed internal and external environmental factors and to estab- lish a framework to develop targeted tools for dealing with the changes such as controlling and/or preventing infec- tion with pathogens and enhancing host immunity against pathogens. This review introduces the current state and trends of discovery metabolomics and reprogramming metabolomics and highlights the importance of repro- gramming metabolomics.

关键词： reprogrammingregulationmetabolomics discovery metabolomicsmetabolomics metabolic strategy metabolic

Characterization of size-resolved effective density of atmospheric particles in an urban atmosphere in Southern China

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Journal of Environmental Sciences 2024年第7期141卷 194-204页

作者： Tingting Xie Liming Cao Jinyi Zheng peng xuan Xiaofeng Huang Laboratory of Atmospheric Observation Supersite School of Environment and EnergyPeking University Shenzhen Graduate SchoolShenzhen 518055China

Effective density(ρ_(eff))is one of the most important physical properties of atmospheric particles,providing important references in exploring the emissions and aging processes of fresh *** this study,a combined system of differential mobility analyzer,centrifugal particle mass analyzer,and condensation particle counter was used to periodically measure theρ_(eff)of atmospheric particles in Shenzhen from Oct.2021 to *** showed that theρ_(eff)of particles with various size presented a bimodal distribution,which could be divided into main density(ρ_(m),main peak,corresponding to relatively dense particles after aging)and sub density(ρ_(s),sub peak,corresponding to fresh particles).The occurrence frequencies ofρ_(s)of particles with diameters of 50 and 80 nm were less than 20%,but were as high as about 40%of that with diameters from 120 to 350 ***ρ_(m)showed increasing trend with the size of particles,whileρ_(s)decreased as the increasing of the size of ***ρ_(eff)on pollution day varied significantly with chemical *** increasing of the proportion of sulfate could promote the increasing ofρ_(eff),while black carbon and organic matter caused opposite effects,which may be related to various factors,including the difference of the material density and morphology of various chemical ***ρ_(eff)of 50,80 and 120 nm particles decreased considerably during the new particle formation event,indicating that organic condensation was an important contributor to new particle growth.

关键词： DMA-CPMA-CPC Effective density Main/sub density Size distribution

Reveal training performance mystery between Tensor Flow and PyTorch in the single GPU environment

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Science China(Information Sciences) 2022年第1期65卷 147-163页

作者： Hulin DAI xuan peng xuanhua SHI Ligang HE Qian XIONG Hai JIN National Engineering Research Center for Big Data Technology and System Service Computing Technology and System LabSchool of Computer Science and Technology Huazhong University of Science and Technology Department of Computer Science University of Warwick

Deep learning has gained tremendous success in various fields while training deep neural networks(DNNs) is very compute-intensive, which results in numerous deep learning frameworks that aim to offer better usability and higher performance to deep learning practitioners. Tensor Flow and Py Torch are the two most popular frameworks. Tensor Flow is more promising within the industry context, while Py Torch is more appealing in academia. However, these two frameworks differ much owing to the opposite design philosophy:static vs dynamic computation graph. Tensor Flow is regarded as being more performance-friendly as it has more opportunities to perform optimizations with the full view of the computation graph. However, there are also claims that Py Torch is faster than Tensor Flow sometimes, which confuses the end-users on the choice between them. In this paper, we carry out the analytical and experimental analysis to unravel the mystery of comparison in training speed on single-GPU between Tensor Flow and Py Torch. To ensure that our investigation is as comprehensive as possible, we carefully select seven popular neural networks, which cover computer vision, speech recognition, and natural language processing(NLP). The contributions of this work are two-fold. First, we conduct the detailed benchmarking experiments on Tensor Flow and Py Torch and analyze the reasons for their performance difference. This work provides the guidance for the end-users to choose between these two frameworks. Second, we identify some key factors that affect the performance,which can direct the end-users to write their models more efficiently.

关键词： deep learning performance comparison TensorFlow PyTorch

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Pyridine-induced interfacial structural transformation of tetraphenylethylene derivatives investigated by scanning tunneling microscopy

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Nano Research 2018年第11期11卷 5823-5834页

作者： xuan peng Linxiu Cheng Xiaoyang Zhu Yanfang Geng Fengying Zhao Kandong Hu xuan Guo Ke Deng Qingdao Zeng CAS Key Laboratory of Standardization and Measurement for Nanotechnology CAS Center for Excellence in Nanoscience National Center for Nanoscience and Technology (NCNST) No. 1 ZhongguancunBeiyitiao Beijing 100190 China Jiangxi College of Applied Technology Ganzhou 341000 China Engineering Research Center of Nano-Geo Materials of Ministry of Education China University of Geosciences Wuhan 430074 China

The two-dimensional self-assembly behaviors of tetraphenylethylene (TPE) molecules are significant for further applications, but reports are rare. The self-assembled structures of two C-2-symmetry TPE derivatives (H4TCPE and H4ETTC) possessing propeller structures and their stimulus responses to the addition of vinylpyridine derivatives were thoroughly studied with the assistance of scanning tunneling microscopy (STM) technique in combination with density functional theory (DFT) calculations. Although their chemical structures were similar, the H4TCPE and H4ETTC molecules self-assembled into closely packed lamellar and quadrilateral structures, respectively, at the 1-heptanoic acid/HOPG interface. After the addition of pyridine derivatives (DPE, PEBP-C4, and PEBP-C8), H4TCPE and H4ETTC showed different responsiveness resulting in different co-assembly structures. The results indicated that the structures of pyridine derivativesincluding backbones and substituentsaffected the intermolecular interactions of both H4TCPE/pyridine and H4ETTC/pyridine systems. The modification of the self-assembly behaviors of propeller-shaped H4TCPE and H4ETTC would contribute to the construction of more complex multilevel nanostructures.

关键词： tetraphenylethylene derivatives propeller structures self-assembly pyridine hydrogen bonding scanning tunneling microscopy (STM)

Microstructure and mechanical properties of transient liquid phase bonding DD5 single-crystal superalloy to CrCoNi-based medium-entropy alloy

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Journal of Materials Science & Technology 2022年第1期96卷 140-150页

作者： Shiwei Li Jinglong Li Junmiao Shi Yu peng xuan peng Xianjun Sun Feng Jin Jiangtao Xiong Fusheng Zhang State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China Shaanxi Key Laboratory of Friction Welding Technologies Northwestern Polytechnical UniversityXi’an 710072China

This study focuses on the transient liquid phase(TLP)bonding of DD5 single-crystal superalloy to Cr Co Nibased medium-entropy alloy(MEA)using a BNi-2 filler *** microstructure and mechanical properties of the TLP-bonded DD5/MEA joint were evaluated,and the microstructural evolution mechanism was *** formation of the isothermal solidification zone(ISZ)depended on the diffusion of the melting-point depressants(Si and B elements)from the liquid filler into the DD5 and MEA substrates,as well as the dissolution of the *** diffused along theγchannel of DD5 and reacted to form M_(5)B_(3)boride,herein referred to as the diffusion-affected zone(DAZ I).Similarly,the Cr_(5)B_(3)boride precipitated in the Ni-rich MEA matrix adjacent to the MEA substrate(i.e.,DAZ II).Additionally,a coherent orientation of[0]_(BCY)//[011]_(FCC)and(002)_(BCY)//(200)_(FCC)was detected between M_(5)B_(3)boride with a body-centered tetragonal(BCT)structure and the face-centered cubic(FCC)*** performance of the joint was dominated by the properties of the bonding *** the bonding time increased from 20to 80 min,the athermal solidification zone(including eutectic microstructure)was gradually replaced by the ISZ exhibiting excellent plastic deformation capability,and the shear strength of the joint was *** maximum shear strength(752 MPa)was achieved when the eutectic-free joint was bonded at 1050℃ for 80 *** fracture morphology revealed a mixture mode,indicating the initiation of cracks in the DAZ II,mainly propagating in the ISZ,and passing through the DAZ I.

关键词： Microstructure Mechanical properties Transient liquid phase bonding Single-crystal superalloy Medium-entropy alloy

Insight into the structural transformation of tetraphenylethylene acids at liquid–solid interface induced by linear aminofunctionalized triazine derivatives and annealing treatment

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Nano Research 2023年第12期16卷 13335-13342页

作者： Ting Meng xuan peng Xunwen Xiao Ke Deng Yu-Wu Zhong Qingdao Zeng CAS Key Laboratory of Standardization and Measurement for Nanotechnology CAS Center for Excellence in NanoscienceNational Center for Nanoscience and Technology(NCNST)Beijing 100190China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China School of Science Nanchang Institute of TechnologyNanchang 330099China Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of PhotochemistryInstitute of ChemistryChinese Academy of SciencesBeijing 100190China College of Materials and Chemical Engineering Ningbo University of TechnologyNingbo 315211China

The interaction between organic photoelectric molecules leads to the formation of a certain aggregation structure,which plays a pivotal role in the charge transport at the intermolecular *** view of this,we investigated the mechanism and law of intermolecular interaction by detecting the self-assembled behaviors between organic photoelectric molecules at the interface by scanning tunneling microscopy(STM).In this work,the structural transformations of tetraphenylethylene acids(H_(4)ETTCs)on graphite surface induced by temperature and triazine derivatives(zcy-19,zcy-27,and zcy-38 molecules)were studied by STM technology and density functional theory(DFT)*** room temperature,zcy-19 and H_(4)ETTC molecules formed a small range of ordered co-assembled nanostructure,while for zcy-27 or zcy-38 molecules,no co-assembled nanostructures were observed and only their own self-assembled structures existed on graphite surface,*** the thermal annealing trials,the original co-assembled H_(4)ETTC/zcy-19 structure disappeared,and only zcy-19 and H_(4)ETTC self-assembled in separate ***,new well-ordered H_(4)ETTC/zcy-27 or H_(4)ETTC/zcy-38 co-assembled structures appeared at different annealing temperatures,*** with DFT calculations,we further analyzed the mechanism of such structural transformations by triazine derivatives and *** reveal that triazine derivatives could interact with H_(4)ETTC by N–H···O and O–H···N hydrogen bondings,and whether temperature or zcy series compounds could achieve successful regulation of H_(4)ETTC assembly behavior is closely associated with the conjugated skeleton length of zcy series compounds.

关键词： tetraphenylethylene acids triazine derivatives annealing treatment scanning tunneling microscopy(STM)