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Theoretical and experimental study of a bi-stable piezoelectric energy harvester under hybrid galloping and band-limited random excitations

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Applied Mathematics and Mechanics(English Edition) 2024年第3期45卷 461-478页

作者： Haitao li Tianyu ZHENG Weiyang QIN Ruilan TIAN Hu DING J.c.JI liqun cHEN Department of Engineering Mechanics North University of ChinaTaiyuan 030051China Department of Engineering Mechanics Northwestern Polytechnical UniversityXi'an 710072China Department of Engineering Mechanics Shijiazhuang Tiedao UniversityShijiazhuang 050043China Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai Frontier Science Center of MechnoinformaticsShanghai Institute of Applied Mathematics and MechanicsSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai 200072China School of Mechanical and Mechatronic Engineering University of Technology SydneyNew South Wales 2007Australia

In the practical environment,it is very common for the simultaneous occurrence of base excitation and *** the combined energy of vibration and wind with a single energy harvesting structure is *** this purpose,the effects of the wind speed and random excitation level are investigated with the stochastic averaging method(SAM)based on the energy *** results of the analytical prediction are verified with the Monte-carlo method(McM).The numerical simulation shows that the introduction of wind can reduce the critical excitation level for triggering an inter-well jump and make a bi-stable energy harvester(BEH)realize the performance enhancement for a weak base ***,as the strength of the wind increases to a particular level,the influence of the random base excitation on the dynamic responses is weakened,and the system exhibits a periodic galloping response.A comparison between a BEH and a linear energy harvester(LEH)indicates that the BEH demonstrates inferior performance for high-speed *** experiments are conducted to investigate the validity of the theoretical prediction and numerical *** experimental findings also show that strong random excitation is favorable for the BEH in the range of low wind ***,as the speed of the incoming wind is up to a particular level,the disadvantage of the BEH becomes clear and evident.

关键词： bi-stability inter-well response galloping band-limited random

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Design and fabrication of Nd-Fe-B magnet with excellent thermal stability

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Journal of Rare Earths 2024年第5期42卷 980-986,I0006页

作者： Rui Han Shengzhi Dong Dong li Dongmin Zhang Hongsheng chen Jiyuan Xu George cHadjipanayis Zhuolin li Ying Zhang Wei li Division of Functional Materials Research Central Iron and Steel Research InstituteBeijing100081China Department of Physics and Astronomy Sharp Lab University of DelawareNewarkDE19716USA Beijing National Laboratory for condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing100190China

A novel Nd-Fe-B type permanent magnet with excellent thermal stability was designed by co replacing Fe in the main phase and the grain boundary *** remanence and coercivity temperature coefficient reach 0.058%/℃and 0.465%/℃in the te mperature range from 25 to 100℃,which are much lower than those of commercial Nd-Fe-B *** enhanced curie temperature is obtained for the novel magnet due to the co substitution,which significantly improves the operating *** microstructure result reveals that an amorphous phase exists in the intergranular grains which is probably responsible for the deterioration of intrinsic *** work can provide a reference for the design and optimization of components of sintered Nd-Fe-B magnets with excellent thermal stability.

关键词： Thermal stability Remanence temperature coefficient Operating temperature Atomic substitution Rare earths

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Efficient guiding and focusing of intense laser pulse using periodic thin slits

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Matter and Radiation at Extremes 2024年第4期9卷 29-39页

作者： L.Xu T.W.Huang K.Jiang c.N.Wu H.Peng P.c.hen R.li H.B.Zhuo c.T.Zhou Shenzhen Key Laboratory of Ultraintense Laser and Advanced Material Technology Center for Intense Laser ApplicationTechnologyand College of Engineering PhysicsShenzhen Technology UniversityShenzhen 518118People’s Republic of China

Slits have been widely used in laser-plasma interactions as plasma optical components for generating high-harmonic light and controlling laser-driven particle ***,we propose and demonstrate that periodic thin slits can be regarded as a new breed of optical elements for efficient focusing and guiding of intense laser *** fundamental physics of intense laser interaction with thin slits is studied,and it is revealed that relativistic effects can lead to enhanced laser focusing far beyond the pure diffractive focusing *** addition,the interaction of an intense laser pulse with periodic thin slits makes it feasible to achieve multifold enhancement in both laser intensity and energy transfer efficiency compared with conventional *** results provide a novel method for manipulating ultra-intense laser pulses and should be of interest for many laser-based applications.

关键词： laser pulse intense

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Development of EPDM composites reinforced by cNTs@SiO_(2)for thermal protection systems of aerospace propulsion:Significant improvement in oxidation and ablation resistance properties

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chinese Journal of Aeronautics 2024年第2期37卷 471-481页

作者： li WANG Jiang li Kang li Yiwei WANG chenyang MA Science and Technology on combustion Internal Flow and Thermal-Structure LaboratoryNorthwestern Polytechnical UniversityXi’an 710072China

carbon Nanotubes(cNTs)reinforced Polymer-Matrix composites(PMcs)is widely used as insulation materials in thermal protection system of aerospace ***,cNTs are prone to oxidation and have high thermal conductivities,which makes it difficult to improve the ablation resistance of insulation materials that contain ***_(2)was encapsulated onto the surface of cNTs(cNTs@SiO_(2)),which were then added to Ethylene Propylene Diene Monomer(EPDM)rubber to prepare the insulation *** analysis and ablation test were used to evaluate the resistance of the insulation materials to thermal oxidation and ***,scanning electron microscopy was performed to analyze their *** revealed that the addition of cNTs@SiO_(2)could visibly reduce the effects of hot corrosion and ablation on insulation *** c-cNTs@SiO_(2)-1 formulation had the best ablative ***,compared with the unencapsulated formulation(c-cNTs-10),the c-cNTs@SiO_(2)-1 formulation reduced the line ablation rate by 51%to 0.0130 mm/s after oxygen-acetylene ***,the ablation mechanism was investigated based on the effects of the cNTs@SiO_(2)additive on their ***,the improvement in ablation performance may be attributed to cNTs@SiO_(2)-induced decreases in thermal conductivity,improvement in the hot corrosion resistance in the char layer,and changes in the microstructure.

关键词： Polymer-Matrix composites(PMcs) carbon Nanotubes(cNTs) Thermal properties Ablation Oxidation

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crack propagation and damage evolution of metallic cylindrical shells under internal explosive loading

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Defence Technology（防务技术） 2024年第9期39卷 133-146页

作者： Yusong Luo Weibing li Junbao li Wenbin li Xiaoming Wang ZNDY of Ministerial Key Laboratory Nanjing University of Science and TechnologyNanjing210094China

This paper investigates the three-dimensional crack propagation and damage evolution process of metallic column shells under internal explosive *** calibration of four typical failure parameters for 40crMnSiB steel was conducted through experiments and subsequently applied to *** numerical simulation results employing the four failure criteria were compared with the differences and similarities observed in freeze-recovery tests and ultra-high-speed *** analysis addressed the critical issue of determining failure criteria for the fracture of a metal shell under internal explosive *** upon this foundation,the damage parameter D_(c),linked to the cumulative crack density,was defined based on the evolution characteristics of a substantial number of *** relationship between the damage parameter and crack velocity over time was established,and the influence of the internal central pressure on the damage parameter and crack velocity was *** in the fracture modes were found under different failure criteria,with the principal strain failure criterion proving to be the most effective for simulating 3D crack propagation in a pure shear fracture *** statistical analysis of the shell penetration fracture radius data,it was determined that the fracture radius remained essentially constant during the crack evolution process and could be considered a *** propagation velocity of axial cracks ranged between 5300 m/s and 12600 m/s,surpassing the Rayleigh wave velocity of the shell material and decreasing linearly with *** increase in shell damage exhibited an initial rapid phase,followed by deceleration,demonstrating accelerated damage during the propagation stage of the blast wave and decelerated damage after the arrival of the rarefaction *** study provides an effective approach for investigating crack propagation and damage *** derived crack propagation and damage evolution law s

关键词： Internal explosive loading Failure criterion crack propagation Damage evolution Freeze-recovery test

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Rainbow Pancyclicity in a collection of Graphs Under the Dirac-type condition

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Acta Mathematicae Applicatae Sinica 2024年第2期40卷 269-274页

作者： Lu-yi li Ping li Xue-liang li center for combinatorics and LPMc Nankai UniversityTianjin 300071China School of Mathematics and Statistics Shaanxi Normal UniversityXi’an 710062China

Let G={Gi:i∈[n]} be a collection of not necessarily distinct n-vertex graphs with the same vertex set V,where G can be seen as an edge-colored(multi)graph and each Gi is the set of edges with color i.A graph F on V is called rainbow if any two edges of F come from different Gis’.We say that G is rainbow pancyclic if there is a rainbow cycle cℓof lengthℓin G for each integerℓ2[3,n].In 2020,Joos and Kim proved a rainbow version of Dirac’s theorem:Ifδ(Gi)≥2/n for each i∈[n],then there is a rainbow Hamiltonian cycle in *** this paper,under the same condition,we show that G is rainbow pancyclic except that n is even and G consists of n copies of Kn/2,n/*** result supports the famous meta-conjecture posed by Bondy.

关键词： rainbow Hamiltonian cycle rainbow pancyclic meta-conjecture

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A hybrid nickel/iron-pyromellitic acid electrocatalyst for oxygen evolution reaction

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Nano Research 2024年第4期17卷 2481-2491页

作者： Guoqi li lin li Wenlong li Fusheng li chunze Yuan Nian Zhang Hui Zhang Tsu-chien Weng School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210China center for Transformative Science ShanghaiTech UniversityShanghai 201210China State Key Lab of Fine chemicals Institute of Artificial PhotosynthesisDUT-KTH Joint Education and Research Center on Molecular DevicesDalian University of Technology(DUT)Dalian 116024China State Key Laboratory of Functional Materials for Informatics Shanghai Institute of Microsystem and Information TechnologyChinese Academy of SciencesShanghai 200050China

The migration of protons during the oxygen evolution reaction(OER)is a key factor that affects the performance of OER *** enhance proton transportation,we designed a catalyst based on nickel/iron-pyromellitic acid(NiFe-PMA)prepared by the electrochemical deposition *** catalyst exhibited a low overpotential of 188 mV at a current density of 10 mA·cm^(-2),a Tafel slope of 28.2 mV·dec^(-1),and long-term stability for 30 days with a current of 50 mA·cm^(-2).We characterized the NiFe-PMA catalyst using various techniques,including Fourier transform infrared(FTIR)spectroscopy,Raman spectroscopy,X-ray photoelectron spectroscopy(XPS),X-ray absorption spectroscopy(XAS),transmission electron microscopy(TEM),scanning electron microscopy(SEM),and inductively coupled plasma-optical emission spectrometry(IcP-OES).Our results showed that NiFe-PMA contains nickel,iron atoms,and both coordinated and uncoordinated carboxylate ***,XPS data confirmed that carboxylate ligands could adjust the outer electronic structure of metal ions,resulting in the high valence state of Ni in *** result of XAS indicated that the nickel atoms present in the catalyst might be easier to maintain a higher chemical *** investigations using kinetic isotope effects(KIEs)and proton inventory revealed that the uncoordinated carboxylic protons played a crucial role in receiving protons during the OER,which promoted the proton transfer of the rate-determining step of the *** novel electrocatalysts provide a new strategy for designing more active and cost-effective catalysts for the OER.

关键词： nickel/iron-pyromellitic acid oxygen evolution reaction kinetic isotope effects

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Phosphorylated cellulose nanofibers establishing reliable ion-sieving barriers for durable lithium-sulfur batteries

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Journal of Energy chemistry 2024年第5期92卷 619-628页

作者： Zihao li Pengsen Qian Hongyang li He Xiao Jun chen Gaoran li School of Materials Science and Engineering Nanjing University of Science and TechnologyNanjing 210094JiangsuChina National Forestry and Grassland Administration Key Laboratory of Plant Fiber Functional Materials Fuzhou 350108FujianChina

The shuttle effect is among the most characteristic and formidable challenges in the pursuit of high-performance lithium-sulfur(li-S)***,phosphorylated cellulose nanofibers(pcNF)are intentionally engineered to establish an ion-sieving barrier against polysulfide shuttling and thereby improve battery *** phosphorylation,involving the grafting of phosphate groups onto the cellulose backbone,imparts an exceptional electronegativity that repels the polysulfide anions from penetrating through the ***,the electrolyte wettability and li^(+)transfer can be significantly promoted by the polar nature of pcNF and the facile li^(+)*** such,rational ion management is realized,contributing to enhanced reversibility in both sulfur and lithium *** a result,li-S cells equipped with the self-standing pcNF separator demonstrate outstanding long-term cyclability with a minimum fading rate of 0.013%per cycle over 1000 cycles at 1 c,and a decent areal capacity of 5.37 mA h cm^(-2) even under elevated sulfur loading of 5.0 mg cm^(-2) and limited electrolyte of 6.0 mL g^(-1).This work provides a facile and effective pathway toward the well-tamed shuttle effect and highly durable li-S batteries.

关键词： lithium-sulfur batteries cellulose Phosphorylation Ion-sieving Shuttle effect

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Prenatal cadmium exposure impairs neural tube closure via inducing excessive apoptosis in neuroepithelium

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Journal of Environmental Sciences 2024年第4期138卷 572-584页

作者： Shiyong Zhu Xuenan li Xueyan Dai Jinlong li college of Veterinary Medicine Northeast Agricultural UniversityHarbin 150030China Key Laboratory of the Provincial Education Department of Heilongjiang for common Animal Disease Prevention and Treatment Northeast Agricultural UniversityHarbin 150030China Heilongjiang Key Laboratory for Laboratory Animals and comparative Medicine Northeast Agricultural UniversityHarbin 150030China

Birth defects have become a public health *** hazardous environmental factors exposure to embryos could increase the risk of birth ***,a toxic environmental factor,can cross the placental barrier during *** woman may be subjected to cadmium before taking precautionary protective ***,the link between birth defects and cadmium remains *** exposure can induce excessive apoptosis in neuroepithelium during embryonic development *** exposure activated the p53 via enhancing the adenosine 5‘-monophosphate(AMP)-activated protein kinase(AMPK)and reactive oxygen species'(ROS)*** cadmium decreases the level of Paired box 3(Pax3)and murine double minute 2(Mdm2),disrupting the process of p53 *** p53 accumulation induced excessive apoptosis in neuroepithelium during embryonic development *** apoptosis led to the failure of neural tube *** study emphasizes that environmental materials may increase the health risk for *** caused the failure of neural tube closure during early embryotic *** women may be exposed by cadmium before taking precautionary protective actions,because of cadmium concentration-containing foods and environmental tobacco *** suggests that prenatal cadmium exposure is a threatening risk factor for birth defects.

关键词： cadmium Neural tube closure Excessive apoptosis p53 Embryogenesis

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Metallurgical performance evaluation of space-weathered chang’e-5 lunar soil

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International Journal of Minerals,Metallurgy and Materials 2024年第6期31卷 1241-1248页

作者： chen li Wenhui Ma Yang li Kuixian Wei center for Lunar and Planetary Sciences Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China Faculty of Metallurgical and Energy Engineering Kunming University of Science and TechnologyKunming 650093China

Space metallurgy is an interdisciplinary field that combines planetary space science and metallurgical *** involves systematic and theoretical engineering technology for utilizing planetary resources in ***,space metallurgy on the Moon is challenging because the lunar surface has experienced space weathering due to the lack of atmosphere and magnetic field,making the mi-crostructure of lunar soil differ from that of minerals on the *** this study,scanning electron microscopy and transmission electron microscopy analyses were performed on chang’e-5 powder lunar soil *** microstructural characteristics of the lunar soil may drastically change its metallurgical *** main special structure of lunar soil minerals include the nanophase iron formed by the impact of micrometeorites,the amorphous layer caused by solar wind injection,and radiation tracks modified by high-energy particle rays inside mineral *** nanophase iron presents a wide distribution,which may have a great impact on the electromagnetic prop-erties of lunar *** ions injected by solar wind may promote the hydrogen reduction *** widely distributed amorph-ous layer and impact glass can promote the melting and diffusion process of lunar ***,although high-energy events on the lun-ar surface transform the lunar soil,they also increase the chemical activity of the lunar *** is a property that earth samples and tradi-tional simulated lunar soil *** application of space metallurgy requires comprehensive consideration of the unique physical and chemical properties of lunar soil.

关键词： space metallurgy chang’e-5 lunar soil space weathering metallurgical performance

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