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Bio-inspired polygonal skeleton structure for vibration isolation:Design,modelling,and experiment

Science China(Technological Sciences) 2020年第12期63卷 2617-2630页

作者： yan Ge WANG Sen ZOU HongXiang ZHAO LinChuan GAO qiuHua zhang WenMing State Key Laboratory of Mechanical System and Vibration School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China Shanghai Aerospace Control Technology Institute Shanghai 201109China

Inspired by the safe landing of a cat falling from a high altitude,a bio-inspired polygonal skeleton(BIPS) structure is proposed,and its nonlinear characteristics are systematically studied to explore its potential application in the suppression of vibration. The polygon is formed by the skeleton structure of the cat’s entire body and the ground. The BIPS system consists of two symmetrical bionic legs with three robs(as skeleton) and four horizontal springs(as muscle). Two bionic legs are connected through the bearing platform(as spine),which could adjust the distance between the two bionic legs. A theoretical model is developed to characterize its stiffness nonlinearity through geometrical and mechanical analysis. Parameter analysis reveals that the BIPS structure has diverse stiffness,including nonlinear positive stiffness and negative stiffness. By imitating adjustment of leg posture and telescopic function of the spine(control the distance between legs),these flexible stiffness properties can be adjusted by structure parameters. In addition,the load capacity and working range can also be designed by the length of the bars,the initial angle,the mounting position,and the spring stiffness. The experimental setup is established,and the vibration isolation performance under various excitation is tested. The experimental results verify the accuracy of the dynamic model and also show that the proposed BIPS structure can suppress the vibration effectively under a variety of excitations. These peculiarities may provide potential possibility of an innovative approach to passive vibration control and isolation.

关键词： bio-inspired polygonal skeleton structure nonlinear stiffness passive vibration isolator

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A theoretical and deep learning hybrid model for predicting surface roughness of diamond-turned polycrystalline materials

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International Journal of Extreme Manufacturing 2023年第3期5卷 620-644页

作者： Chunlei He Jiwang yan Shuqi Wang Shuo zhang Guang Chen Chengzu Ren Tianjin Key Laboratory of Equipment Design and Manufacturing Technology Department of Mechanical EngineeringTianjin UniversityTianjin 30054People’s Republic of China Department of Mechanical Engineering Keio UniversityYokohama 223-8522Japan Tianjin Key Laboratory of the Design and Intelligent Control of the Advanced Mechatronical System School of Mechanical EngineeringTianjin University of TechnologyTianjin 300384People’s Republic of China School of Mechanical Engineering Yanshan UniversityQinhuangdao 066004People’s Republic of China

Polycrystalline materials are extensively employed in *** surface roughness significantly affects the working *** defects,particularly grain boundaries,have a great impact on the achieved surface roughness of polycrystalline ***,it is difficult to establish a purely theoretical model for surface roughness with consideration of the grain boundary effect using conventional analytical *** this work,a theoretical and deep learning hybrid model for predicting the surface roughness of diamond-turned polycrystalline materials is *** kinematic–dynamic roughness component in relation to the tool profile duplication effect,work material plastic side flow,relative vibration between the diamond tool and workpiece,etc,is theoretically *** material-defect roughness component is modeled with a cascade forward neural *** the neural network,the ratio of maximum undeformed chip thickness to cutting edge radius RT S,work material properties(misorientation angle θ_(g) and grain size d_(g)),and spindle rotation speed n s are configured as input *** material-defect roughness component is set as the output *** validate the developed model,polycrystalline copper with a gradient distribution of grains prepared by friction stir processing is machined with various processing parameters and different diamond *** with the previously developed model,obvious improvement in the prediction accuracy is observed with this hybrid prediction *** on this model,the influences of different factors on the surface roughness of polycrystalline materials are *** influencing mechanism of the misorientation angle and grain size is quantitatively *** fracture modes,including transcrystalline and intercrystalline fractures at different RTS values,are ***,optimal processing parameters are obtained with a simulated annealing *** experiments are performed with

关键词： diamond turning material-defect roughness component polycrystalline copper neural network simulated annealing algorithm

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Study on Dynamic Characteristics of Mars Entry Module in Transonic and Supersonic Speeds

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Space(Science & Technology) 2022年第1期2022卷 1-15页

作者： qi Li Rui Zhao Sijun zhang Wei Rao Haogong Wei Beijing Institute of Spacecraft System Engineering CASTBeijingChina 100094 School of Aeronautics and Astronautics Beijing Institute of TechnologyBeijingChina 100081 Advanced Simulation and Modeling Inc.MadisonAL 35758USA

The aerodynamic configuration of the Tianwen-1 Mars entry module that adopts a blunt-nosed and short body shape has obvious dynamic instability from transonic to supersonic speeds,which may bring risk to parachute *** unsteady detached eddy of the entry module cannot be accurately simulated by the Reynolds-Averaged Navier-Stokes(RANS)model,while the computational cost for direct numerical simulation(DNS)and large eddy simulation(LES)is *** is difficult to implement these methods in the coupled engineering calculation of unsteady flow and *** paper proposes the integrated numerical simulation method of computational fluid dynamics and rigid body dynamics(CFD/RBD)based on detached eddy simulation(DES)and calculates and studies the dynamic characteristics of attitude oscillation of the Mars entry module in free flight from transonic to supersonic speeds with one degree of freedom(1-DOF)at small releasing angle of *** addition,the unstable range of Mach number and angle of attack are determined,and the effect of different afterbody shapes on dynamic stability is analyzed.

关键词： unsteady unstable freedom

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Gd-based molecular coolants:Aggregating for better magnetocaloric effect

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Aggregate 2024年第4期5卷 126-139页

作者： Yuan-qi Zhai Wei-Peng Chen Marco Evangelisti Zhendong Fu yan-Zhen Zheng Department of Hepatobiliary Surgery Institute of Advanced Surgical Technology and EngineeringThe First Affiliated Hospital of Xi’an Jiaotong UniversityXi’anShaanxiP.R.China Frontier Institute of Science and Technology Xi’an Key Laboratory of Electronic Devices and Materials ChemistrySchool of ChemistryXi’an Jiaotong UniversityXi’anShaanxiP.R.China Instituto de Nanociencia y Materiales de Aragón CSIC&Universidad de ZaragozaZaragozaSpain Songshan Lake Materials Laboratory DongguanP.R.China

Two series of 3d-Gd mixed-metal phosphonate complexes with either only two gadolinium centers such as{Gd2},{Ni2Gd2},{Co4Gd2},{Co8Gd2},{Fe6Gd2},and{Fe17Gd2}or more than two gadoliniums such as{Co8Gd4},{Mn8Gd4},{Co4Gd6},{Mn4Gd6},{Co6Gd8},{Ni5Gd8},{Ni6Gd6},{Co8Gd8},and{Mn9Gd9}have been solvothermally prepared and magnetothermally *** nearly identical environments of the Gd(III)dimer in theﬁrst series allow us to qualitatively analyze the effect of magnetic exchange coupling on the magne-tocaloric effect(MCE).By doubling,tripling,or quadrupling of the Gd(III)centers,the second series of 3d-Gd mixed-metal complexes was built to further test the other effects of exchange couplings on MCE in more complicated *** the antiferromagnetic coupling cases,the results are nearly identical but diversify when topological spin frustrations are created,whose massive low-lying excited spin states help enhance *** presumably ferromagnetically coupled ones,albeit are rare in phosphonate complexes,they do exhibit excellent ***,the com-plexes with weakly coupled metal centers serve as excellent examples for studying the effect of molecular mass on MCE when its magnitude is expressed in the unit of Joule per kilogram,from which we can see the values are directly proportional to the percentage of the Gd(III)ions in molecular weight.

关键词： 3d-4f lanthanide magnetocaloric effect phosphonate refrigerant

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Synthesis of MXene-supported layered MoS_2 with enhanced electrochemical performance for Mg batteries

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Chinese Chemical Letters 2018年第8期29卷 1313-1316页

作者： Min Xu Na Bai Hong-Xia Li Cong Hu Jing qi Xing-Bin yan School of Physical Science and Technology Lanzhou University Laboratory of Clean Energy Chemistry and Materials State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical Physics Chinese Academy of Sciences

In this paper, the petal-like MoS2/MXene composite has been successfully synthesized by one-step hydrothermal method. With the combination of few-layer MoS2nanosheets and the high conductive MXene substrate, the composite exhibits enhanced capacities of 165 mAh/g at 50 mA/g and outstanding rate performance of 93 mAh/g at 200 mA/g as a cathode material of Mg batteries. Simultaneously, MXene with high conductivity and abundant surface functional groups is proved to be a promising substrate for the wider design of high performance electrode materials.

关键词： Substrate MXene MoS2 Cathode Mg batteries

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Comparison of Mass Transfer Characteristics between Countercurrent-Flow and Crosscurrent-Flow Rotating Packed Bed

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China Petroleum Processing & Petrochemical Technology 2019年第4期21卷 103-111页

作者： qi Guisheng Guo Linya Liu Youzhi zhang Dongming Research Center of Shanxi Province for High Gravity Chemical Engineering and Technology North University of ChinaTaiyuan 030051 Shanxi Province Key Laboratory of Higee-Oriented Chemical Engineering Taiyuan 030051

The rotating packed bed(RPB), mainly including the countercurrent-flow RPB(Counter-RPB) and the crosscurrentflow RPB(Cross-RPB) that are classified from the perspective of gas-liquid contact style, is a novel process intensification device. A significant measurement standard for evaluating the performance of RPB is the mass transfer effect. In order to compare the mass transfer characteristics of Counter-RPB and Cross-RPB with the same size, the liquid volumetric mass transfer coefficient(k_La_e) and effective interfacial area(a_e) were measured under identical operating conditions. Meanwhile, the comparison of comprehensive mass transfer performance was conducted using the ratio of ΔP(pressure drop) to kLae as the standard. Experimental results indicated that kLae and ae increased with the increase in liquid spray density q, gas velocity u, and high gravity factor β. Furthermore, compared with the Cross-RPB, the Counter-RPB has higher liquid volumetric mass transfer coefficient and slightly larger effective interfacial area. The experimental results of comprehensive mass transfer performance showed that the Counter-RPB had higher ΔP/k_La_e than the Cross-RPB with changes in liquid spray density and high gravity factor, and there exists a turning point at 0.71 m/s accompanied by a variation with gas velocity. Moreover, the relative error of experimental value to calculated value, which was computed by the correlative expressions of kLae, was less than 5 %. In conclusion, the mass transfer characteristics of RPB are deeply impacted by the manner in which the flows are established and the Cross-RPB would have a great potential for industrial scale-up applications.

关键词： rotating packed bed mass transfer crosscurrent-flow countercurrent-flow process intensi fication

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Spontaneous low-temperature crystallization of α-FAPbI3 for highly efficient perovskite solar cells

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Science Bulletin 2019年第21期64卷 1608-1616页

作者： Taiyang zhang qiaoling Xu Feng Xu Yuhao Fu Yong Wang yanfa yan Lijun zhang Yixin Zhao School of Environmental Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China Key Laboratory of Automobile Materials Ministry of EducationSchool of Materials Science and EngineeringJilin UniversityChangchun 130012China Department of Physics and Astronomy University of ToledoToledoOH 43606USA State Key Laboratory of Superhard Materials Jilin UniversityChangchun J30012China

Formamidinium lead triiodide(HC(NH2)2PbI3 or FAPbI3)is a promising light absorber for high-efficiency perovskite solar cells because of its superior light absorption range and thermal stability to CH3NH3PbI3(MAPbI3).Unfortunately,it is difficult to fabricate high-quality FAPbI3 thin films to surpass the MAPbI3-based cells due to easily forming unwanted but more stable yellow d-phase and thus requiring high annealing-temperature for wanted photovoltaic-active black ***,we reported a novel low-temperature fabrication of highly crystallized a-FAPbI3 film exhibiting uniaxial-oriented nature with large grain sizes up to 2 ***-principles energetic calculations predicted that this novel deposition should be ascribed to the formation of a high-energy metastable two-dimensional(2D)intermediate of MAFAPbI3 Cl followed by a spontaneous conversion to *** ions exchange reaction during this MAFAPbI3 Cl-FAPbI3 conversion account for the perovskite film uniaxial-oriented grown along the(111)*** large-grain and uniaxial-oriented grown a-FAPbI3 based solar cells exhibited an efficiency up to 20.4%accompanying with low density-voltage(J-V)hysteresis and high stability.

关键词： Perovskite solar cells Spontaneous crystallization FAPbI3 Two-dimensional (2D) perovskites

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High-Temperature Oxidation Resistance of Austenitic Stainless Steel Cr18Ni11Cu3Al3MnNb

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Journal of Iron and Steel Research International 2012年第5期19卷 74-78页

作者： LI Dong-sheng DAI qi-xun CHENG Xiao-nong WANG Rong-rong HUANG yan School of Material Science and Engineering Jiangsu UniversityZhenjiang212013JiangsuChina

The kinetic curve of the high-temperature oxidation of austenitie stainless steel Crl8Ni11 Cu3Al3MnNb at different temperatures was measured by weighting method. It is showed that the oxidation curves at 700 and 800 ℃ followed the parabolic law, and the steel presented an excellent anti-oxidation. The surface morphology and structure of the oxide film were studied by scanning electron microscopy and X-ray diffraction methods. A dense oxide film was attained at 700 and 800 ℃, mainly composed of the hexagonal Al2 O3, Fe2 O3, and a small amount oxide of Cr at 700 ℃. At 900 ℃ the oxide film started to delaminate, and was composed of （Cr,Fe）2O3 and the spinel CuCrMnO4 and Fe（Cr, Al） 2O3.

关键词： austenitic stainless steel high-temperature oxidation oxidation scale cyclic oxidation spinel

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Blue-detuned optical atom trapping in a compact plasmonic structure

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Photonics Research 2017年第5期5卷 436-440页

作者： ZHAO CHEN FAN zhang qi zhang JUANJUAN REN HE HAO XUEKE DUAN PENGFEI zhang TIANCAI zhang YING GU qiHUANG GONG State Key Laboratory for Mesoscopic Physics Collaborative Innovation Center of Quantum Matter Department of PhysicsPeking University Collaborative Innovation Center of Extreme Optics Shanxi University State Key Laboratory of Quantum Optics and Quantum Optics Devices Institute of Opto-Electronics Shanxi University

We theoretically propose blue-detuned optical trapping for neutral atoms via strong near-field interfacing in a plasmonic nanohole array. The optical field at resonance forms a nanoscale-trap potential with an FWHM of 200 nm and about ～370 nm away from the nanohole; thus, a stable 3 D atom trapping independent of the surface potential is demonstrated. The effective trap depth is more than 1 m K when the optical power of trapping light is only about 0.5 m W, while the atom scattering rate is merely about 3.31 s^(-1), and the trap lifetime is about 800 *** compact plasmonic structure provides high uniformity of trap depths and a two-layer array of atom nanotraps, which should have important applications in the manipulation of cold atoms and collective resonance fluorescence.

关键词： Blue-detuned optical atom trapping in a compact plasmonic structure

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Heterojunction interface editing in Co/NiCoP nanospheres by oxygen atoms decoration for synergistic accelerating hydrogen and oxygen evolution electrocatalysis

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Nano Research 2023年第7期16卷 8765-8772页

作者： yan Lin Xiaojiao Cui Yilin Zhao Zhicheng Liu Guoxin zhang Yuan Pan College of Energy Storage Technology Shandong University of Science and TechnologyQingdao 266590China State Key Laboratory of Heavy Oil Processing China University of Petroleum(East China)Qingdao 266580China

Controllable designing of well-defined heterojunction nanostructures provides an insightful strategy for accelerating the kinetics of the hydrogen and oxygen evolution reactions(HER/OER),but such task is still ***,we proposed a protocol of heterojunction interface editing(HIE)strategy by oxygen atoms decoration for synergistic boosting electrocatalytic HER and OER performances.A novel Co/NiCoP nanospheres(NSs)heterojunction was synthesized by crystal seed template transformation method with Ni_(5)P_(4) microspheres as *** effective oxygen atoms interface editing increased the oxidation state of Co atoms and prolonged the Co-P bond length of Co/NiCoP NSs heterojunction,thus the electron localization on P sites was enhanced,leading to the dramatically elevated HER and OER performances *** as-constructed O-Co/NiCoP NSs show excellent electrocatalytic activity with 361 and 430 mV *** hydrogen electrode(RHE)to arrive high current density of 300 mA·cm^(-2)for HER and OER in 1 M KOH as well as good *** proposed HIE concept could provide a new perspective on the catalyst design for energy conversion systems.

关键词： transition metal phosphides heterojunction nanocrystals synthesis bifunctional catalyst electrocatalysis

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