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Advances and trends in plastic forming technologies for welded tubes

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Chinese Journal of Aeronautics 2016年第2期29卷 305-315页

作者： Zhan Mei guo kun Yang He State Key Laboratory of Solidification Processing School of Materials Science and EngineeringNorthwestern Polytechnical University

With the implementation of environmental protection, sustainable development and conservation-oriented policies, components and parts of thin-walled welded tubes have gained increasing application in the aircraft and automotive industries because of their advantages： easily achieving forming and manufacturing process at low cost and in a short time. The current research on welded tube plastic forming is mainly concentrated on tube internal high-pressure forming, tube bending forming, and tube spinning forming. The focuses are on the material properties and char- acterization of welded tubes, finite element modeling for welded tube forming, and inhomogeneous deformation behavior and the mechanism and rules of deformation coordination in welded tube plastic forming. This paper summarizes the research progress in welded tube plastic forming from these aspects. Finally, with a focus on the urgent demand of the aviation, aerospace and automotive industries for high-strength and light-weight tubes, this paper discusses the development trends and challenges in the theory and technology of welded tube plastic forming in the future. Among them, laser tailor-welded technology will find application in the manufacture of high-strength steel tubes. Tube-end forming technology, such as tube flaring and flanging technology, will expand its appli- cation in welded tubes. Therefore, future studies will focus on the FE modeling regarding how to consider effects of welding on residual stresses, welding distortions and microstructure, the inhomo- geneous deformation and coordination mechanism of the plastic forming process of tailor-welded tubes, and some end-forming processes of welded tubes, and more comprehensive research on the formin~ mechanism and limit of welded tubes.

关键词： Constraint effects Deformation coordination Finite element modeling Forming Forming limit Inhomogeneous deforma-tion Material characteristics Welded tube

Precise Pentamers with Diverse Monomer Sequences and Their Thermal Properties

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Chinese Journal of Polymer Science 2022年第5期40卷 447-455页

作者： Rui-Zhe Liu Lei Zhang kun-kun guo Jiang-Tao Xu School of Chemical Engineering UNSW SydneyNSW2052Australia College of Materials Science and Engineering Hunan UniversityChangsha 470082China

Sequenced-defined oligomer has been emerged as one of the hot topics in polymer chemistry due to its capability of precisely controlling both chain length and monomer *** efforts have focused on development of synthetic methodologies using state-ofthe-art chemistry ***,investigating the impact of minor changes in monomer sequence on physical properties of these materials is still ***,four sequenced pentamers are synthesized by a reversible addition-fragmentation chain transfer(RAFT)single unit monomer insertion technique,in which a base pentamer possesses a relatively rigid backbone comprising of five cyclic monomer *** of the cyclic units in this base pentamer is replaced by an acyclic monomer at different locations(the 1st,3rd and 5th unit)to produce three modified pentamers,which leads to a significant decrease of glass transition temperature(Tg)compared to the base ***,the modified pentamers with identical primary structures but distinct monomer sequences also present different Tg values depending on the position of the acyclic monomer *** middle(3rd)position of the acyclic unit causes profound decrease of Tg due to its increased molecular *** synthetic pentamers have been demonstrated to be excellent oligomeric plasticizers to modulate thermal transitions of bulk polymer materials.

关键词： Pentamer Sequence control Single unit monomer insertion Glass transition temperature Sequence-defined oligomer

A survey of heavy–heavy hadronic molecules

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Communications in Theoretical Physics 2021年第12期73卷 86-104页

作者： Xiang-kun Dong Feng-kun guo Bing-Song Zou CAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China School of Physics Central South UniversityChangsha 410083China

The spectrum of hadronic molecules composed of heavy-antiheavy charmed hadrons has been obtained in our previous *** potentials are constants at the leading order,which are estimated from resonance *** experimental candidates of hadronic molecules,say X(3872),Y(4260),three P_(c)states and P_(cs)(4459),fit the spectrum *** success in describing the pattern of heavy-antiheavy hadronic molecules stimulates us to give more predictions for the heavy-heavy cases,which are less discussed in literature than the heavy-antiheavy *** that the heavy-antiheavy hadronic molecules,several of which have strong experimental evidence,emerge from the dominant constant interaction from resonance saturation,we find that the existence of many heavy-heavy hadronic molecules is *** these predicted heavy-heavy states we highlight the DD;molecule and the D^(*)∑_(c)^(*)molecules,which are the partners of the famous X(3872)and Pc *** recently,LHCb collaboration reported a doubly charmed tetraquark state,T_(cc),which is in line with our results for the DD^(*)*** the first experimental signal of this new kind of exotic states,the upcoming update of the LHCb experiment as well as other experiments will provide more chances of observing the heavy-heavy hadronic molecules.

关键词： hadronic molecules heavy-heavy systems Bethe-Salpeter equation constant interaction resonance saturation

Fullerenes and derivatives as electrocatalysts: Promises and challenges

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Green Energy & Environment 2024年第1期9卷 7-27页

作者： kun guo Ning Li Lipiao Bao Xing Lu State Key Laboratory of Materials Processing and Die&Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan430074China

Carbon-based metal-free nanomaterials are promising alternatives to precious metals as electrocatalysts of key energy storage and conversion *** paramount signiﬁcance are the establishment of design principles by understanding the catalytic mechanisms and identifying the active *** from sp2-conjugated graphene and carbon nanotube,fullerene possesses unique characteristics that are growingly being discovered and exploited by the electrocatalysis *** instance,the well-deﬁned atomic and molecular structures,the good electron afﬁnity to tune the electronic structures of other substances,the intermolecular self-assembly into superlattices,and the on-demand chemical modiﬁcation have endowed fullerene with incomparable advantages as electrocatalysts that are otherwise not applicable to other carbon *** increasing studies are being reported on this intriguing topic,it is necessary to provide a state-of-the-art overview of the recent *** review takes such an initiative by summarizing the promises and challenges in the electrocatalytic applications of fullerene and its *** content is structured according to the composition and structure of fullerene,including intact fullerene(e.g.,fullerene composite and superlattices)and fullerene derivatives(e.g.,doped,endohedral,and disintegrated fullerene).The synthesis,characterization,catalytic mechanisms,and deﬁciencies of these fullerene-based materials are explicitly *** conclude it by sharing our perspectives on the key aspects that future efforts shall consider.

关键词： Fullerene Fullerene derivative Metal-free catalyst Structural defect Electrocatalyst

An Alternative-Service Recommending Algorithm Based on Semantic Similarity

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China Communications 2017年第8期14卷 124-136页

作者： kun guo Yonghua Li Yueming Lu Key Laboratory of Trustworthy Distributed Computing and Service Ministry of EducationBeijing University of Posts and TelecommunicationsBeijingChina

With the development of the Internet of Things(Io T), people's lives have become increasingly convenient. It is desirable for smart home(SH) systems to integrate and leverage the enormous information available from IoT. Information can be analyzed to learn user intentions and automatically provide the appropriate services. However, existing service recommendation models typically do not consider the services that are unavailable in a user's living environment. In order to address this problem, we propose a series of semantic models for SH devices. These semantic models can be used to infer user intentions. Based on the models, we proposed a service recommendation probability model and an alternative-service recommending algorithm. The algorithm is devoted to providing appropriate alternative services when the desired service is unavailable. The algorithm has been implemented and achieves accuracy higher than traditional Hidden Markov Model(HMM). The maximum accuracy achieved is 68.3%.

关键词： activity recognition semantic model service recommendation unavailable service

Semi-inclusive lepto-production of hidden-charm exotic hadrons

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Chinese Physics C 2021年第12期45卷 1-7页

作者： Zhi Yang Feng-kun guo School of Physics University of Electronic Science and Technology of ChinaChengdu 610054China Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China CAS Key Laboratory of Theoretical PhysicsInstitute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

We investigate the semi-inclusive production of hidden-charm exotic states,including the X(3872),Z_(c),Zcs and pentaquark P_(c) states,in lepton-proton scattering *** hadrons are close to the thresholds of a pair of charm and anticharm hadrons and are assumed to possess a hadronic molecular structure as their main *** provide order-of-magnitude estimates of the cross sections,we use Pythia to simulate the short-distance productions of the constituent hadrons,which then rescatter to form exotic *** estimates for the X(3872)and Z_(c)(3900)^(±)states are not in conflict with the upper limits measured in the COMPASS experiment for the exclusive photoproduction *** results indicate that the considered hidden-charm states can be copiously produced at the proposed electron-ion colliders EicC and US-EIC.

关键词： hidden-charm exotic hadrons lepto-production

Reducing subspaces of multiplication operators on function spaces

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Applied Mathematics(A Journal of Chinese Universities) 2013年第4期28卷 395-404页

作者： guo kun-yu HUANG Han-song School of Mathematical Sciences Fudan University Department of Mathematics East China University of Science and Technology

This survey presents the brief history and recent development on commutants and reducing subspaces of multiplication operators on both the Hardy space and the Bergman space, and von Neumann algebras generated by multi... 详细信息

关键词： reducing subspace commutant von Neumann algebra Blaschke product holomorphic covering map

Multivariate analysis of surface water quality in the Three Gorges area of China and implications for water management

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Journal of Environmental Sciences 2011年第9期23卷 1460-1471页

作者： Jian Zhao guo Fu kun Lei Yanwu Li Chinese Research Academy of Environmental Sciences Beijing 100012 China.

Multivariate statistical techniques,cluster analysis,non-parametric tests,and factor analysis were applied to analyze a water quality dataset including 13 parameters at 37 sites of the Three Gorges area,China,from 2003–2008 to investigate spatio-temporal variations and identify potential pollution *** cluster analysis,the twelve months of the year were classified into three periods of lowflow （LF）,normal-flow （NF）,and high-flow （HF）;and the 37 monitoring sites were divided into low pollution （LP）,moderate pollution （MP）,and high pollution （HP）.Dissolved oxygen （DO）,potassium permanganate index （COD Mn ）,and ammonia-nitrogen （NH 4 ＋-N） were identified as significant variables affecting temporal and spatial variations by non-parametric *** analysis identified that the major pollutants in the HP region were organic matters and nutrients during NF,heavy metals during LF,and petroleum during *** the MP region,the identified pollutants primarily included organic matter and heavy metals year-around,while in the LP region,organic pollution was significant during both NF and HF,and nutrient and heavy metal levels were high during both LF and *** main sources of pollution came from domestic wastewater and agricultural activities and runoff;however,they contributed differently to each region in regards to pollution *** the HP region,inputs from wastewater treatment plants were significant;but for MP and LP regions,water pollution was more likely from the combined effects of agriculture,domestic wastewater,and chemical *** results provide fundamental information for developing better water pollution control strategies for the Three Gorges area.

关键词： water quality spatial variations seasonal variations multivariate statistical techniques the Three Gorges

Study on the Total Amount Control of Atmospheric Pollutant Based on GIS

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Biomedical and Environmental Sciences 2005年第4期18卷 233-237页

作者： JIAN-PING WANG XI-kun guo College of Science Shantou University Shantou 51500 Guangdong China

To provide effective environmental management for total amount control of atmospheric pollutants. Methods An atmospheric diffusion model of sulfur dioxide on the surface of the earth was established and tested in Shantou of Guangdong Province on the basis of an overall assessment of regional natural environment, social economic state of development, pollution sources and atmospheric environmental quality. Compared with actual monitoring results in a studied region, simulation values fell within the range of two times of error and were evenly distributed in the two sides of the monitored values. Predicted with the largest emission model method, the largest emission of sulfur dioxide would be 54 279.792 tons per year in 2010. Conclusion The mathematical model established and revised on the basis of GIS is more rational and suitable for the regional characteristics of total amount control of air pollutants.

关键词： Total amount control of atmospheric pollutants Atmospheric diffusion model Pollution source GIS