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Novel Traveling Wave Sandwich Piezoelectric Transducer with Single Phase Drive:Theoretical Modeling,Experimental Validation,and Application Investigation

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Chinese Journal of Mechanical Engineering 2021年第5期34卷 206-225页

作者： Liang Wang Fushi Bai Viktor Hofmann jiamei jin Jens Twiefel State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China Institute of Dynamics and Vibration Research Leibniz University Hannover30167 HannoverGermany School of Marine Science and Technology Northwestern Polytechnical UniversityXi’an 710072ShaanxiChina

Most of traditional traveling wave piezoelectric transducers are driven by two phase different excitation signals,leading to a complex control system and seriously limiting their applications in *** overcome these issues,a novel traveling wave sandwich piezoelectric transducer with a single-phase drive is proposed in this *** waves are produced in two driving rings of the transducer while the longitudinal vibration is excited in its sandwich composite beam,due to the coupling property of the combined *** results in the production of elliptical motions in the two driving rings to achieve the drive *** analytical model is firstly developed using the transfer matrix method to analyze the dynamic behavior of the proposed *** vibration characteristics are measured and compared with computational results to validate the effectiveness of the proposed analytical ***,the driving concept of the transducer is investigated by computing the motion trajectory of surface points of the driving ring and the quality of traveling wave of the driving ***,application example investigations on the driving effect of the proposed transducer are carried out by constructing and assembling a tracked mobile *** results indicated that 1)the assembled tracked mobile system moved in the driving frequency of 19410 Hz corresponding to its maximum mean velocity through frequency sensitivity experiments;2)motion characteristic and traction performance measurements of the system prototype presented its maximum mean velocity with 59 mm/s and its maximum stalling traction force with 1.65 N,at the excitation voltage of 500 V_(RMS).These experimental results demonstrate the feasibility of the proposed traveling wave sandwich piezoelectric transducer.

关键词： Traveling wave Sandwich piezoelectric transducer Single phase excitation Transfer matrix method Ultrasonic motor

A piezoelectric tracked vehicle with potential application to planetary exploration

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Chinese Science Bulletin 2012年第11期57卷 1339-1342页

作者： jin jiamei QIAN Fu YANG Ying ZHANG JianHui ZHU KongJun State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China

A piezoelectric driving method for rover vehicles is proposed in this paper. Employing this method, a tracked vehicle driven by friction forces from a frame mounted with piezoelectric elements was developed. The vehicle is designed with no driver sprocket, no idler-wheel and no supporting bogie wheels, and the vehicle thus requires no lubrication and has potential application in planetary exploration. The frame consists of a pair of piezoelectric transducers. Each transducer comprises four annular parts jointed by beams adhered with piezoelectric ceramics. The tracks are set to the outer surface of the annular parts by means of track tension. Traveling rotating waves are generated by piezoelectric transducers in the annular parts, which generate microscopic elliptical motions at the interface of the tracks. The microscopic elliptical motions from the piezoelectric transducers drive the track vehicle to move. Finite elements analysis was carried out to verify the operation principle using commercial software ANSYS. Piezoelectric transducers were fabricated, assembled and tested to validate the concepts of the proposed rover vehicle and confirm the simulation results. A prototype vehicle with mass of 0.57 kg moves at a speed of 4.3 mm/s at a driving voltage of 250 V and operating frequency of 65.53 kHz.

关键词：履带车辆压电元件应用 ANSYS有限元分析压电换能器索具行星驱动链轮

Fluid Pump Using a Bar-shaped Piezoelectric Transducer

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Chinese Journal of Mechanical Engineering 2011年第6期24卷 1130-1135页

作者： jin jiamei WANG Yin YANG Ying ZHANG Jianhui State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China

There are two kinds of piezoelectric pumps:check valve pumps and valve-less *** to use a check valve or not depends upon the application *** achieve large backpressure for higher flow rates,the pump with check valve is ***,adding check valves implies more complex structure and higher probability of valve blocking,*** order to solve the problem,effective driving and transport mechanics with compact construction and reliable service are being *** this paper,using the second-order longitudinal vibration mode of a bar-shaped piezoelectric vibrator for driving fluid,a piezoelectric pump is successfully *** proposed piezoelectric pump consists of coaxial cylindrical shells and a bar-shaped piezoelectric vibrator,which has a disk part and a cone *** lead zirconium titanate ceramic rings fixed in the vibrator are polarized along the thickness *** the second-order longitudinal vibration of the vibrator along its axis is excited,the disk part of the vibrator changes periodically the volume of the chamber and the cone part acts as a pin valve,driving the fluid from the inlet port to the outlet *** elements analysis on the proposed pump model is carried out to verify its operation principle and design by the commercial FEM software *** of the piezoelectric pump were manufactured,assembled,and tested for flow rate and backpressure to validate the concepts of the proposed pump and confirm the simulation results of modal and harmonic *** test results show that the performance of the proposed piezoelectric pump is about 910 mL/min in flow rate with a highest pressure level of 1.5 kPa under 400 V peak-to-peak voltage and 51.7 kHz operating *** is confirmed that this bar-shaped piezoelectric transducer can be effectively applied in fluid transferring mechanism of pump through this research.

关键词： piezoelectric pump check valve longitudinal vibration mode FEM simulation bar-shaped transducer

SF_(6)/N_(2)混合气体综合检测技术研究

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电工技术 2024年第6期 194-197页

作者：周海龙魏存金金佳美赵云龙阮海川国网安徽省电力有限公司阜阳供电公司安徽阜阳236017 安徽源网信息科技有限公司安徽合肥230031

为应对全球温室效应,减少电力设备中温室气体SF_(6)的使用量,提出了SF_(6)混合气体的研究方案。目前SF_(6)混合气体是短期内有效减少SF_(6)气体在电力设备中使用量的方法之一。初步研究表明,SF_(6)/N_(2)混合气体具有较强的电气绝缘性能... 详细信息

为应对全球温室效应,减少电力设备中温室气体SF_(6)的使用量,提出了SF_(6)混合气体的研究方案。目前SF_(6)混合气体是短期内有效减少SF_(6)气体在电力设备中使用量的方法之一。初步研究表明,SF_(6)/N_(2)混合气体具有较强的电气绝缘性能,使得SF_(6)/N_(2)混合气体具有极好的应用前景,因此做好对SF_(6)/N_(2)混合气体的电气设备,特别是GIS的监督和管理变得非常重要。基于此,研发了一款集SF_(6)/N_(2)混合气体混气比、湿度及分解产物检测为一体的检测仪器,并介绍了SF_(6)/N_(2)混合气体检测技术的原理及试验情况。

关键词：温室效应 SF_(6)/N_(2)混合气体检测技术

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双模态切换式步进超声电机

南京航空航天大学学报 2006年第5期38卷 600-604页

作者：金家楣赵淳生南京航空航天大学超声电机研究中心南京210016

利用环形定子的两个弯振模态交替工作的原理设计的一种驻波型步进式超声电机具有开环控制下无累积误差的特性。定子环弯振使定子上的驱动齿分别在两个工作模态下运动产生对转子的驱动力,定子齿与转子齿槽相配合实现步进定位,转子齿槽数... 详细信息

利用环形定子的两个弯振模态交替工作的原理设计的一种驻波型步进式超声电机具有开环控制下无累积误差的特性。定子环弯振使定子上的驱动齿分别在两个工作模态下运动产生对转子的驱动力,定子齿与转子齿槽相配合实现步进定位,转子齿槽数决定电机步距角。分别对应于两个工作模态的两相正弦驱动信号经切换单元提供给电机,对不同电极扇区的激励控制电机转动方向,工作模态间的切换次数决定转动步数。原理样机转子齿槽数为72个,步距角为2.5°。试验结果表明电机运转稳定,没有失步现象。

关键词：超声电机步进驻波频率切换

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Chinese Journal of Electronics 2024年第3期33卷 683-693页

作者： jiamei LIU Lin TAN Hong XU PLA Strategic Support Force Information Engineering University

Deoxys-BC is the primitive tweakable block cipher of the Deoxys family of authenticated encryption *** on existing related-tweakey boomerang distinguishers,this paper improves the boomerang attacks on 11-round Deoxys-BC-256 and 13-round Deoxys-BC-384 by the optimized key guessing and the precomputation *** transfers a part of subtweakey guess in the key-recovery phase to the precomputation resulting in a significant reduction of the overall time *** 11-round Deoxys-BC-256,we give a related-tweakey boomerang attack with time/data/memory complexities of 2218.6/2125.7/2125.7,and give another attack with the less time complexity of2215.8and memory complexity of 2120 when the adversary has access to the full *** 13-round Deoxys-BC-384,we give a related-tweakey boomerang attack with time/dat a/memory complexities of 2k-96+2157.5/2120.4/*** the key size k=256,it reduces the time complexity by a factor of 231compared with the previous 13-round boomerang *** addition,we present two new related-tweakey boomerang distinguishers on 11-round Deoxys-BC-384 with the same probability as the best previous distinguisher.

关键词： Ciphers Memory management Complexity theory Encryption Time complexity

Bio-inspired Hydroxyapatite/Gelatin Transparent Nanocomposites

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Journal of Wuhan University of Technology(Materials Science) 2024年第2期39卷 298-308页

作者：谭军军 WU Mingchen LI Yuzhe PENG jiamei 熊焰 Hubei Province Key Laboratory of Green Materials for Light Industry Collaborative Innovation Center for Green Light-weight Materials and ProcessingHubei University of TechnologyWuhan 430068China

Hydroxyapatite(HA)nanoparticles impart outstanding mechanical properties to organicinorganic nanocomposites in *** by the composite structure of HA nanoparticles and collagen in bone,a high performance HA/gelatin nanocomposite was first *** nanocomposites have much better mechanical properties(elongation at break 29.9%,tensile strength 90.7 MPa,Young’s modulus 5.24 GPa)than pure gelatin films(elongation at break 9.3%,tensile strength 90.8 MPa,Young’s modulus 2.5 GPa).In addition,the composite films keep a high transmittance in visible wavelength range from 0%to 60%of the HA solid *** differences in properties are attributed to the homogeneous distribution of HA nanoparticles in the gelatin polymer matrix and the strong interaction between the particle surfaces and the gelatin *** protocol should be promising for HA-based nanocomposites with enhanced mechanical properties for biomedical applications.

关键词： hydroxyapatite nanocomposites sodium citrate gelatin colloidal stability

On the role of sliding friction effect in nonlinear tri-hybrid vibration-based energy harvesting

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Applied Mathematics and Mechanics(English Edition) 2024年第8期45卷 1295-1314页

作者： jiamei WANG Siukai LAI Chen WANG Yiting ZHANG Zhaolin CHEN Department of Civil and Environmental Engineering The Hong Kong Polytechnic UniversityHong KongChina The Hong Kong Polytechnic University Shenzhen Research Institute Shenzhen 518057Guangdong ProvinceChina Hebei Key Laboratory of Mechanical Reliability for Heavy Equipments and Large Structures Yanshan UniversityQinghuangdao 066000Hebei ProvinceChina School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China

This work aims to develop an experimental investigation into the effectiveness of the sliding-mode approach for hybrid vibration-based energy harvesting.A proposed sliding-mode triboelectric-electromagnetic-piezoelectric energy harvesting model involves a cantilever beam with a tip mass exposed to magnetic and frictional *** experimental findings indicate that the system can achieve its peak inter-well oscillation output within a low-frequency range of 4 Hz–6 *** has a lesser impact on the open-circuit voltage output at an excitation acceleration of 1.5g compared with *** distribution of tri-stability changes with the presence of *** model provides a deeper understanding of the influence of the dry friction coefficient(0.2–0.5) on the interactive behaviors of different generator units.

关键词： sliding mode tri-hybrid energy harvesting friction nonlinear behavior

Alterations of soil aggregates and intra-aggregate organic carbon fractions after soil conversion from paddy soils to upland soils:Distribution,mineralization and driving mechanism

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Pedosphere 2024年第1期34卷 121-135页

作者： Longfei KANG jiamei WU Chunfeng ZHANG Baoguo ZHU Guixin CHU College of Life Science Shaoxing UniversityShaoxing 312000China The Key Laboratory of Oasis Eco-agriculture Xinjiang Production and Construction Group/Department of Resources and Environmental SciencesAgronomy CollegeShihezi UniversityShihezi 832000China Hunan Institute of Agricultural Environment and Ecology Changsha 410000China Jiamusi Branch Heilongjiang Academy of Agricultural SciencesJiamusi 154007China

Investigating the impacts of soil conversion on soil organic carbon(OC) content and its fractions within soil aggregates is essential for defining better strategies to improve soil structure and OC sequestration in terrestrial ecosystems. However, the consequences of soil conversion from paddy soil to upland soil for soil aggregates and intra-aggregate OC pools are poorly understood. Therefore, the objective of this study was to quantify the effects of soil conversion on soil aggregate and intra-aggregate OC pool distributions. Four typical rice-producing areas were chosen in North and South China, paired soil samples(upland soil converted from paddy soil more than ten years ago vs. adjacent paddy soil) were collected(0–20 cm) with three replicates in each area. A set of core parameters(OC preservation capacity, aggregate carbon(C) turnover, and biological activity index) were evaluated to assess the responses of intra-aggregate OC turnover to soil conversion. Results showed that soil conversion from paddy soil to upland soil significantly improved the formation of macro-aggregates and increased aggregate stability. It also notably decreased soil intra-aggregate OC pools, including easily oxidized OCa(EOCa), particulate OCa(POCa), and mineral-bound(MOCa) OC, and the sensitivity of aggregate-associated OC pools to soil conversion followed the order: EOCa(average reduction of 21.1%) > MOCa(average reduction of 15.4%) > POCa(average reduction of 14.8%). The potentially mineralizable C(C_(0)) was significantly higher in upland soil than in paddy soil, but the corresponding decay constant(k) was lower in upland soil than in paddy soil. Random forest model and partial correlation analysis showed that EOCa and pH were the important nutrient and physicochemical factors impacting k of C mineralization in paddy soil,while MOCa and C-related enzyme(β-D-cellobiohydrolase) were identified as the key factors in upland soil. In conclusion, this study evidenced that soil conversion

关键词： decay constant easily oxidized organic C macro-aggregate meso-aggregate micro-aggregate mineral-bound organic C particulate organic C potentially mineralizable C