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Velocity plus displacement equivalent force control for real-time substructure testing

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Earthquake Engineering and Engineering Vibration 2018年第1期17卷 87-102页

作者： zhou huimeng d.wagg wang tao Key Laboratory of Earthquake Engineering and Engineering Vibration of China Earthquake Administration Harbin 150080 China Institute of Engineering Mechanics China Earthquake Administration PR China d.p.. of Mechanical Engineering University of Sheffield United Kingdom

This paper employs a velocity plus displacement（V＋d）-based equivalent force control（EFC） method to solve the velocity/displacement difference equation in a real-time substructure test. This method uses type 2 feedback control loops to replace mathematical iteration to solve the nonlinear dynamic equation. A spectral radius analysis of the amplification matrix sh.w. that the type 2 EFC-explicit, Newmark-β method has beneficial numerical characteristics for this method. Its stability limit of Ω = 2 remains unchanged regardless of the system damping because the velocity is achieved with very high accuracy during simulation. In contrast, the stability limits of the central difference method using direct velocity prediction and the EFC-average acceleration method with linear interpolation are sh.w. to decrease with an increase in system damping. In fact, the EFC-average acceleration method is sh.w. to change from unconditionally stable to conditionally stable. we also sh.w.that if an over-damped system with a damping ratio of 1.05 is considered, the stability limit is reduced to Ω =1.45. Finally, the results from an experiment with a single-degree-of-freedom structure installed with a magneto-rheological（MR） damper are presented. The results demonstrate that the proposed method is able to follow both displacement and velocity commands with moderate accuracy, resulting in improved test performance and accuracy for structures that are sensitive to both velocity and displacement inputs. Although the findings of the study are promising, additional test data and several further improvements will be required to draw general conclusions.

关键词： real-time substructure test EFC velocity/displacement control newmark-β method stability

Recent development of chemically complex metallic glasses: from accelerated compositional design, additive manufacturing to novel applications

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Materials Futures 2022年第1期1卷 9-31页

作者： J Y zhang z Q zhou z B zhang M h park Q Yu z Li J Ma A d wang h G huang M Song B S Guo Q wang Y yang d.p.rtment of Mechanical Engineering College of EngineeringCity University of Hong KongKowloon TongKowloonHong KongPeople’s Republic of China Shenzhen Key Laboratory of high performance Nontraditional Manufacturing College of Mechatronics and Control EngineeringShenzhen UniversityShenzhenGuangdong 518060People’s Republic of China School of Materials Science and Engineering Dongguan University of TechnologyDongguanGuangdong 523808People’s Republic of China Institute of Materials China Academy of Engineering PhysicsJiangyouSichuan 621907People’s Republic of China State Key Laboratory of powder Metallurgy Central South UniversityChangshaHunan 410083People’s Republic of China Institute of Advanced wear&Corrosion Resistant and Functional Materials Jinan UniversityGuangzhouGuangdong 510632People’s Republic of China Institute of Materials Laboratory for MicrostructuresShanghai UniversityShanghai 200444People’s Republic of China d.p.rtment of Materials Science and Engineering College of EngineeringCity University of Hong KongKowloon TongKowloonHong KongPeople’s Republic of China d.p.rtment of Advanced design and System Engineering College of EngineeringCity University of Hong KongKowloon TongKowloonHong KongPeople’s Republic of China

Metallic glasses(MGs)or amorphous alloys are an important engineering material that has a history of research of about 80–90 *** different fast cooling methods were developed for multi-component MGs between 1960s and 1980s,1990s witnessed a surge of research interest in the development of bulk metallic glasses(BGMs).Since then,one central theme of research in the metallic-glass community has been compositional design that aims to search for MGs with a better glass forming ability,a larger size and/or more interesting properties,which can hence meet the demands from more important *** this review article,we focus on the recent development of chemically complex MGs,such as high entropy MGs,with new tools that were not available or mature yet until recently,such as the state-of-the-art additive manufacturing technologies,high throughput materials design techniques and the methods for big data analyses(*** learning and artificial intelligence).we also discuss the recent use of MGs in a variety of novel and important applications,from personal healthcare,electric energy transfer to nuclear energy that plays a pivotal role in the battle against global warming.

关键词： metallic glasses amorphous alloys alloy design additive manufacturing machine learning high throughput materials design

Monolayer MoS_(2)synaptic devices synergistically modulated by Na^(+)ions and sulfur vacancies for neuromorphic computing and.p.in perception stimulation

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Journal of Materials Science & Technology 2023年第32期163卷 121-131页

作者： Y.B.Liu d.Cai T.C.zhao M.Shen X.zhou z.h.zhang X.w.Meng d.E.Gu State Key Laboratory of Electronic Thin Films and Integrated devices University of Electronic Science and Technology of ChinaChengdu 610054China College of Chemistry and Materials Science Sichuan Normal UniversityChengdu 610066China Laboratory of Controllable preparation and Application of Nanomaterials Chinese Academy of SciencesBeijing 100190China

Ion based synaptic devices(ISds)are one of the excellent candidates for neuromorphic ***,most of ISds utilized additional ion sources to supply ions for adjusting the conductance of the device channel,which might hinder the large-scale integration for fabricating hierarchical artificial neural *** a high-performance monolayer MoS_(2) ISd is demonstrated using Na^(+)ions d.p.d in MoS_(2) lattice as ion *** from the Na^(+)ions and S vacancy defects in the MoS_(2) lattice,the device not only exhibits various synaptic plasticity(long-and short-term plasticity)and typical biological features(pain-perceptual nociceptors and associative learning),but also has a low synaptic event response voltage(100 mV)and a low energy consumption(0.92 pJ)for a synaptic event.A dissociation-adsorptionmigration-binding model is proposed to elaborate the resistance switching mechanism,which is corroborated by density functional theory calculations and *** addition,an artificial neural network(ANN)based on MoS_(2) ISds is simulated for the recognition of the MNIST handwritten *** deviation of the recognition accuracy is less than 8%compared to the ideal floating-point numeric *** results provide a new strategy for fabricating high-performance ISds for neuromorphic computing.

关键词： 2d materials Monolayer Molybdenum disulfide Synapses Neuromorphic computing

Improving the hard magnetic properties by intragrain pinning for Ta d.p.d nanocrystalline Ce-Fe-B alloys

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Journal of Materials Science & Technology 2019年第9期35卷 1877-1885页

作者： J.S.zhang w. Li X.F. Liao h.Y. Yu L.z. zhao h.X. zeng d.R. peng z.w. Liu School of Materials Science and Engineering South China University of TechnologyGuangzhou510640China Innovative Center for Advanced Materials (ICAM) Hangzhou Dianzi UniversityHangzhou310012China

To develop Ce based.p.rmanent magnets with high performance/cost ratio, Ta d.p.ng is was employed to enhance the magnetic performance of Ce-Fe-B alloys. For melt spun Cei7Fe78-xTaxB6 (x = 0-1) alloys, the coercivity hc increases from 439 to 553 kA/m with increasing x value from 0 to 0.75. Microstructure characterizations indicate that Ta d.p.ng is helpful for grain refinement. A second.p.ase of TaB2 is observed in Ce17Fe77.25tao.75B6 alloy, which acts as the pinning center of the magnetic domains, resulting in the change of coercivity mechanism from nucleation type to nucleation +pinning type. The micromagnetic simulation confirms that non-magnetic particles within hard magnetic phase can increase the demagnetization field around them and it is crucial for preventing the further magnetization reverse by pinning effect. Take the advantage of Ta d.p.ng for enhancing the coercivity, Ce content of Ce-Fe-B alloy can be further cut down to increase the remanence Jr due to the reduced volume fraction of CeFe2 phase and increased Fe/Ce ratio. As a result, a good combination of magnetic properties with hc = 514 kA/m, Jr = 0.49 T, and the maximum energy product (Bh)max = 36 kJ/m^3 have been obtained in Ce15Fe79.25tao.75B6 alloy. It is expected that the present work can serve as a useful reference for designing new permanent magnetic materials with low-cost.

关键词： Melt-spinning permanent magnets Second phase Coercivity mechanism Thermal stability

Energy-efficient recovery of tetrahydrofuran and ethyl acetate by triple-column extractive distillation:entrainer design and.p.ocess optimization

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Frontiers of Chemical Science and Engineering 2022年第2期16卷 303-315页

作者： Ao yang yang Su tao Shi Jingzheng Ren weifeng Shen Teng zhou School of Chemistry and Chemical Engineering Chongqing UniversityChongqing 401331China d.p.rtment of Industrial and Systems Engineering The Hong Kong Polytechnic UniversityHong KongChina School of Intelligent Technology and Engineering Chongqing University of Science&TechnologyChongqing 401331China process Systems Engineering Otto-von-Guericke University MagdeburgD-39106 MagdeburgGermany process Systems Engineering Max Planck Institute for Dynamics of Complex Technical SystemsD-39106 MagdeburgGermany

An energy-efficient triple-column extractive distillation process is developed for recovering tetrahydrofuran and ethyl acetate from industrial *** process development follows a rigorous hierarchical design procedure that involves entrainer design,thermodynamic analysis,process design and optimization,and heat *** computer-aided molecular design method is firstly used to find.p.omising entrainer candidates and the best one is determined via rigorous thermodynamic ***,the direct and indirect triple-column extractive distillation processes are proposed in the conceptual design *** two extractive distillation processes are then optimized by employing an improved genetic ***,heat integration is performed to further reduce the process energy *** results indicate that the indirect extractive distillation process with heat integration sh.w. the highest performance in terms of the process economics.

关键词： extractive distillation solvent selection conceptual design process optimization heat integration

Rational design of chemically complex metallic glasses by hybrid modeling guided machine learning

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npj Computational Materials 2021年第1期7卷 1242-1251页

作者： z.Q.zhou Q.F.he X.d.Liu Q.wang J.h.Luan C.T.Liu Y.yang d.p.rtment of Mechanical Engineering College of EngineeringCity University of Hong KongKowloonHong KongChina College of Mechatronics and Control Engineering Shenzhen UniversityShenzhenChina Laboratory for Structures Institute of Materials ScienceShanghai UniversityShanghaiChina d.p.rtment of Materials Science and Engineering College of EngineeringCity University of Hong KongKowloonHong KongChina d.p.rtment of Advanced design and System Engineering College of EngineeringCity University of Hong KongChina

The compositional design of metallic glasses(MGs)is a long-standing issue in materials science and ***,traditional experimental approaches based on empirical rules are time consuming with a low *** this work,we successfully developed a hybrid machine learning(ML)model to address this fundamental issue based on a database containing~5000 different compositions of metallic glasses(either bulk or ribbon)reported since *** the prior works relying on empirical parameters for featurization of data,we designed modeling guided data descriptors in line with the recent theoretical models on amorphization in chemically complex alloys for the development of the hybrid classification-regression ML *** hybrid ML modeling was validated both numerically and *** importantly,it enabled the discovery of MGs(either bulk or ribbon)through the ML-aided deep search of a multitude of quaternary to scenery alloy *** computational framework herein established is expected to accelerate the design of MG compositions and expand their applications by probing the complex and multi-dimensional compositional space that has never been explored before.

关键词： alloy glasses metallic

REMOVE INCLUSIONS FROM ALUMINUM MELT INELECTROMAGNETIC FIELd

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Acta Metallurgica Sinica(English Letters) 2000年第5期13卷 1068-1074页

作者： T.X.Li z.M.Xu B.d.Sun d.Shu Y.h.zhou School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200030China

Electromagnetic separation of non-metallic inclusions from Al-Si melt is studied by theoretical analysis and experiments on self-designed electromagnetic separation apparatus. Metallographs and LECO Image Analysis System were used to analyze the content of alumina in aluminum alloy before and after electromagnetic separation. It is seen that removal effciency increases with the increase of electromagnetic force (EMF) and diameter of inclusion particles while decreases with the increase of melt velocity and height of separator. All alumina particles with diamete of 14μm have been removed successfully from the melt.

关键词： aluminum melt alumina particle electromagnetic separation removal efficiency

Lanthanide-organic frameworks based on terphenyl-tetracarboxylate ligands:syntheses,structures,optical properties and selective sensing of nitro explosives

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Science China Chemistry 2017年第8期60卷 1130-1135页

作者： zhou,Xinhui zhu,Yali Li,Liang yang,tao wang,Jin huang,wei Key Laboratory for Organic＇ Electronics and Infot~ation displays Institute of Advanced Materials Nanjing University of Posts ＆ Telecommunications Nanjing 210023 China Key Laboratory of Flexible Electronics Institute of Advanced Materials Jiangsu National Synergetic innovation Center Jbr Advanced Materials Nanjing Tech University Nanjing 211816 China School of College of Opto-Electronic Engineering Nanjing University of Posts and Telecommunications Narding 210023 China

Three isostructural three-dimensional （3d） lanthanide-based metal-organic frameworks [Ln2L（h2L）（NMp）2]＇h20 （Ln=Sm（l）, Eu （2）, Gd （3）; h4L= 1,1 ＇：4＇, 1 ＂-terphenyl-2＇,4,4＂,5＇-tetracarboxylic acid; NMp=N-methyl-2-pyrrolidone） have been synthesized and structurally characterized. In 1-3, two Ln3＋ ions are doubly-bridged by two oxygen atoms of two carboxylate groups to form the dinuclear Lnz（Oco ）a unit. Each Ln2（Ocoo ）2 unit links with four h2L2 ligands and four L4- ligands to lead to the 3d framework, which can be rationalized as a new trinodal 4,4,8-connected （44.62）（45.6）（412.616） topological network by considering the dinuclear Ln2（Ocoo ）2 units as 8-connected nodes and L4-/h2L2- ligands as planar 4-connected nodes, respectively. 1 and 3 exhibit blue emission originated from the ligand with the emission maximum at 384 nm, while 2 sh.w. intense characteristic red emission of Eu3＋ ions and weak ligand-centered emission. Moreover, 2 has fluorescent quenching response towards the aromatic nitro compounds, especially for the 3,4-dinitrotoluene （3,4-dNT） with the linear Stern-Volmer relationship in the concentration range of 0-1 mM and the quenching constant （Ksv） of 2.084-103 M 1.

关键词： lanthanide metal-organic frameworks(MOFs) sensor nitro explosives

Nodal superconducting gap in LiFep revealed by NMR:Contrast with LiFeAs

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Chinese physics B 2021年第4期30卷 113-118页

作者： A F Fang R zhou h Tukada J yang z deng X C wang C Q Jin Guo-Qing zheng d.p.rtment of physics Beijing Normal UniversityBeijing 100875China Institute of physics Chinese Academy of Sciencesand Beijing National Laboratory for Condensed Matter PhysicsBeijing 100190China Songshan Lake Materials Laboratory Dongguan 523808China d.p.rtment of physics Okayama UniversityOkayama 700-8530Japan

Identifying the uniqueness of Fep-based superconductors may shed new lights on the mechanism of superconductivity in ***,we report nuclear magnetic resonance(NMR) studies on LiFep and LiFeAs which have the same crystal structure but different pnictogen *** NMR spectrum is sensitive to inhomogeneous magnetic fields in the vortex state and can provide the information on the superconducting pairing symmetry through the temperature d.p.ndence of London penetration d.p.h λ_(L).we find that λ_(L) saturates below T~0.2 T_(C) in LiFeAs,where T_(C) is the superconducting transition temperature,indicating nodeless superconducting ***,by using a two-gaps model,we simulate the temperature d.p.ndence of λ_(L) and obtain the superconducting gaps of LiFeAs,as Δ_(1)=1.2 kB T_(C) and Δ_(2)=2.8 k_(B)T_(C),in agreement with previous result from spin-lattice *** LiFep,in contrast,λ_(L) does not sh.w.any saturation down to T~0.03 T_(C),indicating nodes in the superconducting gap ***,we demonstrate that strong spin fluctuations with diffusive characteristics exist in LiFep,as in some cuprate high temperature superconductors.

关键词： iron-based superconductor nuclear magnetic resonance superconducting pairing symmetry spin fluctuations