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Modification of Pb(Zr,Ti)O3 by Doping Mo based on High Power Ultrasonic Transducer

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Journal of Wuhan University of Technology(Materials Science) 2020年第6期35卷 1038-1042页

作者： XING Xiuqin ZHU Xijing School of Mechanical Engineering North University of ChinaTaiyuan 030051China

In view of the special requirements of transducers for power ultrasonic processing,the piezoelectric ceramic material Pb(Zr,Ti)O3 was modified by adding other effective *** piezoelectric ceramic piece has a good crystal phase structure,a stable piezoelectric constant,a higher dielectric constant,and a lower dielectric loss by adding a small amount of Sr^2+,Ba^2+,Ga^2+,Sn^4+,Nb^5+,*** properties are well suited to requirements of power ultrasonic transducer more than 1 000 *** crystal phase structure and surface morphology of the modified piezoelectric ceramic chips were analyzed by X-ray and scanning electron microscopy (SEM) to prove that the piezoelectric ceramic chips have good crystal structure and *** dielectric constant of the polarized piezoelectric ceramic chips was measured using an LCR ***,the piezoelectric ceramic chips were used to design the ultrasonic transducer,and the transducer was analyzed and measured by the impedance *** measurement results show that the performance of the piezoelectric ceramic chips is reasonable and feasible.

关键词： piezoelectric ceramic power ultrasonic transducer doping modification surface morphology

A static-dynamic energy harvester for a self-powered ocean environment monitoring application

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Science China(Technological Sciences) 2022年第4期65卷 893-902页

作者： XUE Feng CHEN Liang LI ChunCheng REN Jing YU JunBin HOU XiaoJuan GENG WenPing MU JiLiang HE Jian CHOU XiuJian Science and Technology on Electronic Test and Measurement Laboratory North University of ChinaTaiyuan 030051China

Ocean intelligent buoy is important for ocean environment *** the increase of requisite sensors and transportable data,a long power supply has become a problem to be solved *** this work,a hybrid nanogenerator integrating triboelectric,piezoelectric,electromagnetic,photovoltaic,and thermotropic units is proposed to maximize ocean ambient energy harvesting,which includes static energy(solar and thermal energy)and dynamic energy(wave energy).Compared with a device with a single energy conversion mechanism,this structural design breaks the limit of harvesting time and natural conditions during the energy harvesting process,thereby increasing the harvested *** energy harvesting is realized by the thermoelectric(TG)and photovoltaic(PV)units located inside the device and the PV unit attached to the device *** show that the maximum open-circuit voltage and short-circuit current are 5 V and 41 mA in the external PV and 1.33 V and 49 mA in the internal PV under 30000 Lux illumination,*** open-circuit voltage and short-circuit current of the TG unit are 5 V and 15 m A,*** core component of the dynamic generation unit is the gimbal used to harvest wave energy by the triboelectric nanogenerator(TENG),piezoelectric generator(PENG),and electromagnetic *** the frequency is 2.4 Hz,the maximum peak-to-peak power of the TENG,PENG,and EMG are 0.25,1.58,and 13.8 mW,***,an intelligent ocean buoy is fabricated by the integration of an energy harvester,a power management circuit,sensors,a microcontroller,and a wireless communication *** by static and dynamic energy,temperature signal,humidity signal,GPS signal,and sound signal are sent to the receiving terminal *** ocean energy harvester proposed in this work is of great significance for ocean energy harvesting and ocean wireless monitoring systems.

关键词： hybrid nanogenerator static energy dynamic energy energy harvester wireless monitoring system

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Competitive Exclusion Principle Revised by Noise

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Chinese Physics Letters 2010年第1期27卷 279-281页

作者：刘永姜王爱玲王彪刘兆华 Key Laboratory for AMT Shanxi North University of China Taiyuan 030051

A fundamental tenet in theoretical ecology is the competitive exclusion principle. Two competitive species for a limited resource cannot coexist and thus one of the species will be driven to extinction. However, we show that noise can revise this principle in a resonance-like manner, which makes coherence resonance in the system. Our obtained results well enrich the findings in the interaction of populations in ecosystems, which may explain some filed observations in the real world.

关键词： Chinese climate network complex systems small world community

Structure of Pb(Zr,Ti)O3(PZT)for Power Ultrasonic Transducer

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Journal of Wuhan University of Technology(Materials Science) 2018年第4期33卷 884-887页

作者：邢秀琴祝锡晶 LI Jing School of Mechanical Engineering North University of ChinaTaiyuan 030051China

To improve the performance of ultrasonic transducer, the samples of PZT were improved by doping. The doped PZT was observed and analyzed from the following aspects： the crystal phase structures, the surface morphologies and the dielectric constant. According to the transducer parameter requirements for ultrasonic machining, there are also requirements for the parameters of piezoelectric ceramics. The high performance PZT was prepared by doping the elements of Ga, Ba, Nb, Sn, and Sr in PZT. The doped PZT is suitable for power ultrasonic machining at 20 kHz through analysis using X-ray diffraction（XPD）, a scanning electron microscope（SEM） and LCR meter. Therefore, the excellent performance of transducer for power ultrasonic machining is guaranteed.

关键词： piezoelectric ceramic ultrasonic transducer PZT

Analysis of Orientation Relationships,Carbon Partitioning and Strengthening Mechanism of a Novel Ultrahigh Strength Steel

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Journal of Wuhan University of Technology(Materials Science) 2022年第4期37卷 692-698页

作者： LIU Heping YANG Hengzhe SUN Fenger LIU Langlang ZHOU Diaoyu School of Material Science and Engineering North University of ChinaTaiyuan 030051China

The orientation relationships,carbon partitioning and strengthening mechanism of a novel ultrahigh strength steel were analyzed in depth during the complex process of heat *** experimental results reveal that the(011)α//()γ,[100]α//[011]γ orientation relationships can be drawn between martensite and retained *** position and angle of martensite and retained austenite are shown more clearly from the stereographic ***,the calculated results show that the carbon content near the austenite interface is the highest in the shorter carbon allocation *** the further increase of time,its carbon content gradually ***,a model of the relationship between yield strength and strengthening mechanism was *** was proved that the main strengthening components contributing to the yield strength include Orowan strengthening,grain-size strengthening and dislocation *** main strengthening mechanism of steel in this experiment is dislocation strengthening.

关键词： quenching and partitioning orientation relationships carbon partitioning strengthening mechanism laser additive manufacturing

Synthesis and characterization of super paramagnetic composite photocatalyst-Titania/silica/nickel ferrite

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Particuology 2011年第5期9卷 475-479页

作者： Yu Li Xiufang Dong Junping Li School of Chemical Engineering and Environment North University of China Taiyuan 030051 Shanxi China

Composite photocatalysts with TiO2 porous shell and magnetic core were synthesized by using NiFe2O4 as a magnetic core, SiO2 as an intermediate layer and polyethylene glycol with molecular weight of 1000 （PEG 1000） as a template direction agent. The samples were characterized with N2 adsorption-desorption, X-ray diffraction （XRD）, transmission electron microscopy （TEM）, scanning electron microscopy （SEM）, vibrating sample magnetometry （VSM） and ultraviolet-visible （UV-vis） spectroscopy. The results showed that the obtained composites are spherical particles about 50 nm in diameter. The mesoporous TiO2 with magnetic core calcined at 350 ℃, 450 ℃, and 550 ℃ was found to have, respectively, different specific surface areas （94, 86, and 68 m^2/g） and average pore sizes （1.4, 2.2, and 2.8 nm）. The photocatalytic activity was investigated for degradation of nitrobenzene under UV irradiation. Nitrobenzene was decomposed in 300 min under irradiation of an 8 W UV lamp with a peak wavelength of 253.7 nm. The composite nanoparticles exhibited high photocatalytic efficiency and super paramagnetic nature for cleaning polluted water by magnetic separation.

关键词： Titania Mesoporous Photocatalyst Core-shell

Monolithic homogeneous integrated miniaturized triboelectric nanogenerator with an inner air cavity for energy harvesting

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Science China(Technological Sciences) 2021年第3期64卷 662-672页

作者： HOU XiaoJuan ZHANG ShengNan YU JunBin YANG ChangJun ZHANG Ning HE Jian CHOU XiuJian Science and Technology on Electronic Test and Measurement Laboratory North University of ChinaTaiyuan 030051China

To realize the high-efficiency acquisition of environmental mechanical energy,traditional triboelectric nanogenerators(TENGs)based on contact-separation consist of two separate triboelectric *** large contact-separation gap increases the overall volume of the device,making it difficult to realize miniaturization and *** work,therefore,presents a fully enclosed all-in-one-shaped flexible TENG(FEAST)with an air cavity using rubber mixing and high-temperature *** air pressure inside the enclosed air cavity facilitates effective contact-separation of the *** homogeneous integration between the triboelectric layer and the electrode layer enhances structural firmness without using extra spacer *** developed FEAST presents excellent mechanical durability even after 10000 *** increasing the active contact area between the triboelectric materials,a maximum peak-peak output voltage,current,and power density of 130 V,1.1μA,and277 m W/m^(2),respectively,were obtained with an effective stress area of 1 ***,the fully enclosed structure ensures that the output performance is not affected by the external *** FEAST was fixed onto the sole of a shoe to demonstrate its applicability in harvesting mechanical energy from human ***,the developed method provides a simple approach for optimizing the structure of TENGs and is compatible with large-scale manufacturing.

关键词： triboelectric nanogenerator air cavity homogeneous integration all-in-one shape energy harvesting

Crystal phase control and ignition properties of HNS/CL-20 composite microspheres prepared by microfluidics combined with emulsification techniques

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Particuology 2024年第2期85卷 241-251页

作者： Yi Liu Yunyan Guo Rui Zhu Jinqiang Zhou Zhengxu Lin Kai Han Chongwei An Jingyu Wang Bidong Wu School of Environment and Safety Engineering North University of ChinaTaiyuan030051China School of Engineering Beijing Institute of TechnologyBeijing100081China Shanxi Province Ultrafine Powder Engineering Technology Research Center Taiyuan030051China

Improved controllability and energy density of ignition agents are of great significance for the devel-opment of energetic composite *** this study,droplet microfluidics and emulsification tech-niques were combined to prepare HNS/CL-20 composite microspheres with polyglycidyl azide polymer(GAP)as the *** influence of binder content on the morphology of microspheres was investi-gated,and the microspheres were characterized and tested for particle size,crystal structure,thermal decomposition,dispersibility,mechanical sensitivity,combustion behavior and detonation *** results showed that microspheres prepared with a binder content of 3%had higher sphericity and particle size *** microspheres retained the crystal structure of both HNS and CL-20(ε-type).Compared with raw HNS,the microspheres had higher apparent activation energy,better safety per-formance,and good *** ignition experiments and detonation performance tests show that HNS/CL-20 composite microspheres have excellent ignition performance,obvious combustion flame,and significant energy release effects,which are expected to achieve high energy and high-speed response of the igniter,thus improving the ignition reliability in special environments or systems.

关键词： Droplet microfluidics Emulsification technology Energetic materials Composite microspheres Crystal phase control Ignition

Pyrolysis Mechanism of a Cyclotriphosphazene-Based Flame-Retardant Epoxy Resin by ReaxFF Molecular Dynamics

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China Petroleum Processing & Petrochemical Technology 2023年第3期25卷 136-152页

作者： Jiang Shuaijun Meng Weifeng Wan Yongqing Qin Weihua Liu Xiaoqing Lan Yanhua School of Environment and Safety Engineering North University of ChinaTaiyuan 030051China

Cyclotriphosphazene derivatives can effectively improve the flame retardancy and fire safety of epoxy resins(EPs)via their influence on the pyrolysis *** this work,the effects of hexa(5-methyl-2-pyridinoxyl)cyclotriphosphazene(HMPOP)incorporation on the initial pyrolysis of an EP at 500–3500 K were studied using the ReaxFF *** pyrolysis fragments,initial reaction pathways,and main products were identified for the EP and EP/HMPOP *** activation energies were derived by fitting the weight percentage curves for solid species during the pyrolysis reactions and the obtained values were in good agreement with experimental *** initial EP pyrolysis reactions included four major decomposition modes,which primarily involved the cleavage of C–O and C–N *** main pyrolysis products were H_(2)O,CO,C_(2)H_(4),and CH_(2)*** bonded with the oxygen-containing fragments to form larger molecular fragments and reduced the amounts of C_(0)–C_(4) products,especially that of the harmful gas CH_(2)***,HMPOP promoted the formation of carbon clusters and reduced the generation of combustible gases,ultimately decreasing the capacity for fire propagation.

关键词： epoxy cyclotriphosphazene ReaxFF pyrolysis flame retardancy