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Flexible multilayer MEMS coils and their application in energy harvesters

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Science China(Technological Sciences) 2024年第4期67卷 1282-1293页

作者： ZHANG Jie HOU XiaoJuan qian Shuo BI XiaoXue HU DongXu LIU JianJun GENG WenPing MU JiLiang HE Jian chou XiuJian Science and Technology on Electronic Test and Measurement Laboratory North University of ChinaTaiyuan 030051China School of Software North University of ChinaTaiyuan 030051China

Electromagnetic vibration energy harvesters are promising for the power supply of wireless sensor nodes,small electronic devices,and wearable *** electromagnetic harvesters usually increase output by increasing the size of coils and magnets,limiting the improvement of energy conversion efficiency and power *** this study,multilayer microelectromechanical system(MEMS)coils were prepared using flexible electronics,and their high integration performance in arbitrary space was utilized to greatly improve the utilization of the space magnetic field by the electromagnetic *** core magnet of the generator was magnetically balanced to achieve levitation,which improved the sensitivity and reduced fatigue damage compared with traditional spring *** wound coils on the top and bottom of the magnet and the flexible coils on the sides worked together to improve the energy efficiency and output of the *** output performance of the device with different number distributions was simulated using mathematical models to obtain the optimal structural *** results show that by introducing flexible multilayer MEMS coils on the side surface of the energy harvester,the open-circuit voltage of the energy generators increased from 7 to 10 V by more than 43%.Flexible multilayer MEMS coils can enhance energy conversion rates and possess compact dimensions,making them suitable for integration onto complex *** the vibration energy harvesting system testing,the maximum peak power of the harvester was 7.1 m W at an acceleration of1 g and a resonant frequency of 11 Hz with a resistor of 3.5 kΩinternal ***,a 470μF capacitor can be charged to 3.5 V within 10 s to drive a hygrothermograph to work for more than 80 s and can supply a light bulb *** strategy shows the great potential of vibration-energy-driven electromagnetic generators for powering small electronics in limited spaces.

关键词： electromagnetic harvester mechanical energy harvesting multilayer MEMS coils magnetic levitation overall space magnetic field flexible planar coils

A high-performance electromagnetic energy harvester for scavenging ultra-low frequency vibration energy of human foot movement

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Science China(Technological Sciences) 2024年第5期67卷 1391-1400页

作者： HU JiaJun qian Shuo WU Hui HU DongXu NIU LiXin BI XiaoXue ZHANG Jie HOU XiaoJuan GENG WenPing MU JiLiang HE Jian chou XiuJian Science and Technology on Electronic Test and Measurement Laboratory North University of ChinaTaiyuan030051China School of Software North University of ChinaTaiyuan030051China

In our daily lives,low-frequency kinetic energy primarily manifests as ***,effective harnessing of lowfrequency kinetic energy remains a formidable *** paper proposes a rope-driven rotor that rotates around an axis and consists of an ultra-high-molecular-weight polyethylene(UHMWPE)wire wrapped around a metal *** rotor can convert ultra-low frequency vibration/linear motion into rapid rotation by pressing the top at low frequencies and driving the rope for a quick *** harvester can generate up to 36.25 m W power using a 0.1-mm-diameter UHMWPE wire as the rotor when periodically pressed down to 20 mm at a frequency of 1 Hz.A simple power generation floor is assembled,generating 28.58-m W power with a matching load at a frequency of 1.5 ***,the harvester can increase the charging voltage of a 0.47-F supercapacitor from 0 to 6.8 V within 10 *** addition,the harvester can harvest energy through a light finger press motion,and the energy obtained can also support the continuous operation of multiple electronic devices *** study introduces an effective method for harvesting ultra-low frequency energy and has great prospects in the field of power generation floor and human movement energy harvesting.

关键词： electromagnetic energy harvester rope-shaft coupling structure human motion ultra-low frequency

Perpendicularly assembled oriented electrospinning nanofibers based piezoresistive pressure sensor with wide measurement range

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Nano Research 2024年第7期17卷 6493-6501页

作者： Xiaoxue Bi Zhigang Duan Xiaojuan Hou Shuo qian Mengjiao Yuan Jiajun Hu Jie Zhang Yuchen Lu Yanli Liu Jian He Zhiling Peng Xiujian chou School of Mechanical and Electrical Engineering North University of ChinaTaiyuan 030051China Science and Technology on Electronic Test and Measurement Laboratory North University of ChinaTaiyuan 030051China School of Software North University of ChinaTaiyuan 030051China School of Information and Communication Engineering North University of ChinaTaiyuan 030051China

With the rapid development of wearable electronics,flexible pressure sensors have attracted wide attention in human–computer interaction and intelligent ***,it is a challenge to achieve a sensor with high sensitivity,wide measurement range,and wearing ***,we develop an oriented electrospinning thermoplastic polyurethane/polyacrylonitrile(TPU/PAN)nanofibers(OETPN)based piezoresistive pressure sensor(PONPS)in which the active layer and the electrode are assembled *** interdigital electrode is fabricated by spraying silver nanowires(AgNWs)on the OETPN through a mask *** active layer is composed of OETPN coated with MXene,encapsulated on the electrode by polyurethane(PU)*** porous structure of nanofibers membrane broadens the measurement range of the *** oriented nanofibers as active layer can improve the sensitivity in low pressure,because oriented nanofibers without interweaving nanofibers are more compressible than disordered *** prepared using the spraying method creates nanoscale microstructure and increases *** perpendicular assembly has greater response between the active layer and the electrode than the parallel assembly to improve the *** sensor exhibits high sensitivity(6.71 kPa^(−1),0.02–2 kPa)and wide measurement range(0.02–700 kPa).The sensor can detect weak signals such as radial artery.A pressure array constructed precisely represents the distribution of *** intelligent throat is created by combining machine learning algorithms with the *** can detect and recognize subtle throat vibrations while speaking,achieving recognition accuracy up to 100%using support vector machine(SVM)for five words with different *** fabricated sensor shows promising prospects in personal healthcare and intelligent robots.

关键词： oriented nanofibers perpendicular assembly parallel assembly intelligent throat machine learning algorithms

Flexible wide-range multidimensional force sensors inspired by bones embedded in muscle

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Microsystems & Nanoengineering 2024年第3期10卷 49-61页

作者： Jie Zhang Xiaojuan Hou Shuo qian Jiabing Huo Mengjiao Yuan Zhigang Duan Xiaoguang Song HuiWu Shuzheng Shi Wenping Geng Jiliang Mu Jian He Xiujian chou Science and Technology on Electronic Test and Measurement Laboratory North University of ChinaTaiyuan 030051China School of Software North University of ChinaTaiyuan 030051China School of Mechanical Engineering Hebei University of ArchitectureZhangjiakou 075000China HBIS Group Co.Ltd. Shijiazhuang 050023China

Flexible sensors have been widely studied for use in motion monitoring,human‒machine interactions(HMIs),personalized medicine,and soft intelligent ***,their practical application is limited by their low output performance,narrow measuring range,and unidirectional force ***,to achieve flexibility and high performance simultaneously,we developed a flexible wide-range multidimensional force sensor(FWMFS)similar to bones embedded in muscle *** adjustable magnetic field endows the FWMFS with multidimensional perception for detecting forces in different *** multilayer stacked coils significantly improved the output from theμV to the mV level while ensuring FWMFS *** optimized FWMFS exhibited a high voltage sensitivity of 0.227 mV/N(0.5–8.4 N)and 0.047 mV/N(8.4–60 N)in response to normal forces ranging from 0.5 N to 60 N and could detect lateral forces ranging from 0.2–1.1 N and voltage sensitivities of 1.039 mV/N(0.2–0.5 N)and 0.194 mV/N(0.5–1.1 N).In terms of normal force measurements,the FWMFS can monitor finger pressure and sliding trajectories in response to finger taps,as well as measure plantar pressure for assessing human *** plantar pressure signals of five human movements collected by the FWMFS were analyzed using the k-nearest neighbors classification algorithm,which achieved a recognition accuracy of 92%.Additionally,an artificial intelligence biometric authentication system is being developed that classifies and recognizes user *** on the lateral force measurement ability of the FWMFS,the direction of ball movement can be distinguished,and communication systems such as Morse Code can be *** research has significant potential in intelligent sensing and personalized spatial recognition.

关键词： password Morse force

Identifying the origin of porous evolution of microsized bismuth in potassium-ion batteries

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Science China Chemistry 2024年第7期67卷 2234-2239页

作者： Shenxu Chu Kaixiang Lei qian Yang Jiaxin Li Yuqing Zhao Mengjia Gu Lin Li Xing Hu Yu Zhang Zhuo Chen Shuo Shi Shulei chou Shijian Zheng Tianjin Key Laboratory of Materials Laminating Fabrication and Interface Control Technology School of Materials Science and EngineeringHebei University of TechnologyTianjin 300401China Institute for Carbon Neutralization Technology College of Chemistry and Materials EngineeringWenzhou UniversityWenzhou 325035China

Microsized bismuth(Bi)with in-situ constructed three-dimensional(3D)porous network has been considered as a promising anode for high-performance potassium-ion batteries(PIBs).However,the mechanism of the in-situ porous evolution of microsized Bi during the charge/discharge process is still ***,various electrolytes are employed to disclose the origin of porous evolution of microsized Bi in *** and theoretically,the 3D porous network originates from the uniform interfacial charge distribution on the Bi surface in the linear ether-based *** addition,the universality of the interfacial charge distribution mechanism was verified by microsized Sn and *** in-situ constructed 3D porous network of Bi enables a superior potassium storage performance in a wide temperature range from-40 to 40℃.More importantly,the K_(0.9)Mn_(0.7)Ni_(0.3)O_(2)||Bi full cell delivers excellent cycling stability(a high capacity retention of 88.44%even after 2,000 cycles)and good temperature *** work gives a distinct clarification of the origin of the porous evolution of microsized Bi during cycling,which is critical for developing high-performance PIBs.

关键词： potassium-ion batteries microsized Bi porous evolution linear ether-based electrolyte interfacial charge distribution

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Exceptional catalytic effect of novel rGO-supported Ni-Nb nanocomposite on the hydrogen storage properties of MgH_(2)

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Journal of Materials Science & Technology 2024年第5期172卷 83-93页

作者： Samuel Guemou Liuting Zhang Shuai Li Yiqun Jiang Tao Zhong Zichuan Lu Ren Zhou Fuying Wu qian Li School of Energy and Power Instrumental Analysis CenterJiangsu University of Science and TechnologyZhenjiang 212003China National Engineering Research Center for Magnesium Alloys&National Key Laboratory of Advanced Casting Technologies&College of Materials Science and Engineering Chongqing UniversityChongqing 400044China Chongqing Institute of New Energy Storage Materials and Equipment Chongqing 401135China Max Planck Institute for Iron Research Düsseldorf 40237Germany

The design of an excellent active catalyst to improve the sluggish kinetic and thermodynamic properties of magnesium hydride(MgH_(2))remains a great challenge to achieve its practical *** this study,a novel Ni-Nb/rGO nanocomposite catalyst was successfully prepared by one-spot hydrothermal and sub-sequent calcination *** novel Ni-Nb/rGO nanocomposite exhibits an exceptional catalytic effect on improving MgH_(2) sorption ***,the onset desorption temperature of MgH_(2)+10 wt%Ni-Nb/rGO composite is reduced to 198℃,much lower than that of undoped MgH_(2)(330℃).In-terestingly,the composite can release 5.0,5.9,and 6.0 wt%H_(2) within 10 min at 245,260,and 275℃,***,the dehydrogenated MgH_(2)+10 wt%Ni-Nb/rGO composite starts to absorb hydrogen even at room temperature with approximate 2.75 wt%H_(2) uptake at 75℃under 3 MPa H_(2) pressure within 30 min and exhibits excellent stability by maintaining 6.0 wt%hydrogen content after 20 cycles at 300℃.chou’s model suggests that the de/hydrogenation kinetics of Ni-Nb/rGO-modified MgH_(2) switches from surface penetration model to diffusion model at lower ***,the ac-tivation energies(E a)for the de/hydrogenation of MgH_(2)+10 wt%Ni-Nb/rGO are reduced to 57.8 kJ/mol and 33.9 kJ/mol,which are significantly lower than those of undoped MgH_(2).The work demonstrates that the addition of a novel ternary Ni-Nb/rGO catalyst is an effective strategy to not only boost the sorption kinetics of MgH_(2) but also maintain its cycling property.

关键词： Hydrogen storage materials Magnesium hydride Ni-Nb/rGO Kinetic analysis Catalytic mechanism

Thermodynamic assessment of Mg-Ni-Y system focusing on long-period stacking ordered phases in the Mg-rich corner

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Journal of Magnesium and Alloys 2022年第11期10卷 3250-3266页

作者： Cheng Liu Qun Luo Qin-Fen Gu qian Li Kuo-Chih chou State Key Laboratory of Advanced Special Steels&Shanghai Key Laboratory of Advanced Ferrometallurgy School of Materials Science and EngineeringShanghai UniversityShanghai 200444China Australian Synchrotron Clayton 3168Australia

The long-period stacking ordered phases(LPSOs) in Mg-Ni-Y system have been attracting great interest as effective strengthening components because of their unique structural characteristics and deformation ***,the phase relationships in LPSOs are complicated and unclear,which restricts the design of advanced magnesium-based *** aim of the present work is to experimentally determine the phase equilibria relationships focusing on LPSOs and establish the thermodynamic description for Mg-Ni-Y *** types of LPSOs,that is,14H,12R,18R and 10H,are confirmed through equilibrated alloys and high-resolution transmission electron microscopy(HR-TEM).The formation enthalpies of LPSOs(14H,12R,18R and 10H) are calculated based on density functional theories(DFT) calculations.A new ternary compound,termed as τ phase,is observed for the first time which is likely to be the distorted structure of 12R as determined from the TEM image which shows a 12-layer closed packing plane distance of 3.252nm and a shear angle of 83.2°between(0002) and(10■0) *** on the determined phase equilibria relationship,the Mg-Ni-Y system is assessed and a selfconsistent description is obtained where the LPSOs are modeled as the stoichiometric *** comparison between the calculation result and experimental data suggests the accuracy of the present thermodynamic database in the Mg-rich corner.

关键词： LPSO phases Crystal structures Phase equilibria Thermodynamics

Thermodynamic prediction of thermal diffusivity and thermal conductivity in Mg–Zn–La/Ce system

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Journal of Materials Science & Technology 2022年第2期97卷 147-155页

作者： Tianci Xie Hui Shi Hongbin Wang Qun Luo qian Li Kuo-Chih chou State Key Laboratory of Advanced Special Steel&Shanghai Key Laboratory of Advanced Ferrometallurgy&School of Materials Science and Engineering Shanghai UniversityShanghai 200444China

Basic thermal properties and mechanical properties are critical parameters for the structural magnesium *** atoms and second phases can improve mechanical properties,but are deteriorating the heat dissipation *** experimental determination of alloys,it is found that REMg12 phases have fewer negative impacts on thermal diffusivities thanτ;*** the same intermetallic compound,the solute atom Zn have more negative influences on thermal diffusivities of Mg-Zn-La/Ce alloys than the content of second *** order to quantitatively evaluate thermal conductivities and further design Mg alloys with both high strength and high thermal conductivity,a calculated method is provided to describe the thermal diffusivity of alloys as a function of alloy composition and phase constitution.A set of parameters for expression of thermal diffusivity of Mg-Zn-La/Ce alloys were obtained through assessing the experimental *** thermal conductivities of Mg-Zn-La/Ce system were predicted and agreed well with experimental values with calculation error of 1.6%and standard error of±3.0 W/(m K).The calculation method considering thermal diffusivity resistivity improves the calculation accuracy and would be physically significant.

关键词： Mg-Zn-La/Ce alloys Thermal conductivity Mechanical properties CALPHAD Thermodynamics

Thermodynamic prediction of martensitic transformation temperature in Fe-C-X(X=Ni,Mn,Si,Cr)systems with dilatational coefficient model

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Journal of Materials Science & Technology 2022年第17期112卷 291-300页

作者： Hongcan Chen Wei Xu Qun Luo qian Li Yu Zhang Jingjing Wang Kuo-Chih chou State Key Laboratory of Advanced Special Steel&Shanghai Key Laboratory of Advanced Ferrometallurgy&School of Materials Science and Engineering Shanghai UniversityShanghai 200444China State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819China National Engineering Research Center for Magnesium Alloy Chongqing UniversityChongqing 400044China Ansteel Beijing Research Institute Co. LtdBeijing 102211China

Martensitic transformation is significant to strengthen steels,but its thermodynamic prediction is restricted to simple systems due to lacking multicomponent interaction *** driving forces of martensitic transformation can be divided into chemical and non-chemical driving *** magnetic parameters are carefully optimized because it affects the magnetic Gibbs free energy of austenite and ferrite,and have big impact on the chemical driving *** dilatational strain energy provides major contribution to non-chemical driving force,thus the integrated-models for dilatational coefficient are constructed in a wide composition and temperature range based on the experimental dilatational *** expands the scope of application of thermodynamic model and improved prediction accuracy of martensitic transformation temperature(M_(s)).The prediction error reaches 5.6%for Fe-C-X(X=Ni,Mn,Si,Cr)and6.5%for Fe-C-Mn-Si-X(X=Cr,Ni)steels.

关键词： Martensitic transformation Thermodynamics Dilatational strain energy Linear expansion coefficient Fe-C-X(X=Ni,Mn,Si,Cr)system