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Influences of Environmental Motion Modes on the Efficiency of Ultrathin Flexible Piezoelec trie Energy Harvesters

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Acta Mechanica Solida Sinica 2019年第5期32卷 611-620页

作者： Chaofeng Lii yangyang zhang He zhang Zhicheng zhang Yisheng Chen College of Civil Engineering and Architecture Zhejiang University310058 HangzhouPeople Republic of China Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province Zhejiang University310027 HangzhouPeople's Republic of China Soft Matter Research Center Zhejiang University310027 HangzhouPeople's Republic of China

Harvesting energy from ambient vibration sources with ultrathin flexible piezoelectric energy harvesters(PEHs)for battery-free electronics has received attention in recent ***,the excitation modes in the environment and human body motion are more complicated than the ideal harmonic modes employed in previous theoretical analyses,and their influence on the efficiency of PEHs has received little *** this study,these environmental excitation modes are classified into three types,i.e.,the triangular,sinusoidal,and square wave modes,with varied duty *** derived theoretically the output power of flexible PEHs under these excitation modes and establish a simple scaling law,in which the normalized output power depends only on two combined normalized parameters,i.e.,the intrinsic system parameter and the excitation *** reveal that the output power of PEHs changes dramatically for different excitation modes with varied duty ratios even when all the other parameters including excitation ampli tude,excitation frequency,elec trical parameter,and geometrical and material parameters of the PEHs are *** paper may provide a systematic understanding in the effect of exc计ation modes on the output power of flexible PEHs and promote the realization of energy harvesting from the complex environmental and human body motions.

关键词： Flexible piezoelec trie energy harves ter Environmental excitation modes Energy harvesting efficiency Theoretical predictions Scaling law

Comparison of the very high cycle fatigue behaviors of INCONEL 718 with different loading frequencies

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Science China(Physics,Mechanics & Astronomy) 2013年第3期Mechanics & Astronomy) .卷 617-623页

作者： zhang yangyang DUAN Zheng SHI HuiJi Key Laboratory of Applied Mechanics Tsinghua UniversityChinese Ministry of Education

In order to clarify the differences of very high cycle fatigue(VHCF) behavior of nickel based superalloy IN718 with different loading frequencies,stress-controlled fatigue tests were carried out by using ultrasonic testing method(20 KHz) and rotary bending testing method(52.5 Hz),both at room temperatures,to establish stress versus cycles to failure(S-N) *** disclosed that cycles to failure at a given stress level increased with an increase of the applied frequency,i.e.,the higher frequency produced an upper shift of the S-N *** analysis suggested that crack initiation and propagation behaviors had large differences:cracks in low-frequency tests preferentially initiated from multiple sources on the specimen surface,while in high-frequency tests,cracks mostly originated from a unique source of subsurface ***,frequency-involved modeling was proposed,based on the damage accumulation theory,which could well illustrate qualitatively those comparisons due to different loading frequencies.

关键词： frequency effect very high cycle fatigue IN718 superalloy

Single Failure Routing Protection Algorithm in the Hybrid SDN Network

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Computers, Materials & Continua 2020年第7期64卷 665-679页

作者： Haijun Geng Jiangyuan Yao yangyang zhang School of Software Engineering Shanxi UniversityTaiyuan030006China School of Computer Science and Cyberspace Security Hainan UniversityHaikou570228China College of Engineering Northeastern University Boston02115USA

Loop free alternate(LFA)is a routing protection scheme that is currently deployed in commercial ***,LFA cannot handle all single network component failure scenarios in traditional *** Internet service providers have begun to deploy software defined network(SDN)technology,the Internet will be in a hybrid SDN network where traditional and SDN devices coexist for a long ***,this study aims to deploy the LFA scheme in hybrid SDN network architecture to handle all possible single network component failure ***,the deployment of LFA scheme in a hybrid SDN network is described as a 0-1 integer linear programming(ILP)***,two greedy algorithms,namely,greedy algorithm for LFA based on hybrid SDN(GALFAHSDN)and improved greedy algorithm for LFA based on hybrid SDN(IGALFAHSDN),are proposed to solve the proposed ***,both algorithms are tested in the simulation environment and the real *** results show that GALFAHSDN and IGALFAHSDN can cope with all single network component failure scenarios when only a small number of nodes are upgraded to SDN *** path stretch of the two algorithms is less than 1.36.

关键词： Multipath routing network availability routing protection algorithm network failure hybrid SDN network

Electromechanical modeling of eye fatigue detecting using flexible piezoelectric sensors

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Science China(Information Sciences) 2018年第6期61卷 87-94页

作者： Chaofeng LU Shuang WU yangyang zhang Yangkun DU College of Civil Engineering and Architecture Zhejiang University Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province Zhejiang University Soft Matter Research Center Zhejiang University Department of Engineering Mechanics Zhejiang University

Eye fatigue has attracted significant interest due to its potential harm to human daily activities. An ultrathin flexible piezoelectric sensor was currently designed and fabricated to detect eye fatigue by deforming together with the eyelid epidermis. Herein we develop a theoretical model to illustrate the correlation between the eyelid motion and the signals output by the piezoelectric sensor. The theoretical predictions on the eyelid motion based on the measured electrical output agree well with the in vivo observations in experiment. A simple scaling law is established to evaluate the impacts of different parameters on the function ability of the flexible piezoelectric sensor. The results may provide useful guidelines for designing and optimizing similar devices for alike biological motions.

关键词： electromechanical model flexible piezoelectric sensors eye fatigue monitoring scaling law micromechanics

Experimental investigation of the inhibition of deep-sea mining sediment plumes by polyaluminum chloride

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International Journal of Mining Science and Technology 2024年第1期34卷 91-104页

作者： Fengpeng zhang Xuguang Chen Jiakang Wei yangyang zhang Weikun Xu Hao Li College of Engineering Ocean University of ChinaQingdao 266100China Shandong Province Key Laboratory of Ocean Engineering Ocean University of ChinaQingdao 266100China China Merchants Marine and Offshore Research Institute Co. Ltd.Shenzhen 518000China National Deep Sea Center Qingdao 266237China

Deep-sea sediment disturbance may occur when collecting polymetallic nodules,resulting in the creation of plumes that could have a negative impact on the ecological *** study aims to investigate the potential solution of using polyaluminum chloride(PAC)in the water *** effects of PAC are examined through a self-designed simulation system for deep-sea polymetallic nodule collection and sediment samples from a potential deep-sea mining *** experimental results showed that the optimal PAC dose was found to be 0.75 g/*** with the test conditions without the addition of PAC,the presence of PAC leads to a reduction in volume,lower characteristic turbidity,smaller diffusion velocity,and shorter settling time of the *** indicates that PAC inhibits the entire development process of the *** addition of PAC leads to the flocculation of mm-sized particles,resulting in the formation of cm-sized *** flocculation of particles decreases the rate of erosion on the seabed by around 30%.This reduction in erosion helps to decrease the formation of ***,when the size of suspended particles increases,it reduces the scale at which they ***,the settling velocity of flocs(around 10^(-2) m/s)is much higher that of compared to sediment particles(around 10^(-5) m/s),which effectively reduces the amount of time the plume remains in suspension.

关键词： Deep-sea mining Deep-sea polymetallic nodules Sediment plume Polyaluminum chloride Jet impact Particle flocculation

Weak Hardy-type spaces associated with ball quasi-Banach function spaces I:Decompositions with applications to boundedness of Calderón-Zygmund operators

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Science China Mathematics 2021年第9期64卷 2007-2064页

作者： yangyang zhang Dachun Yang Wen Yuan Songbai Wang Laboratory of Mathematics and Complex Systems(Ministry of Education of China) School of Mathematical SciencesBeijing Normal UniversityBeijing100875China College of Mathematics and Statistics Hubei Normal UniversityHuangshi435002China

Let X be a ball quasi-Banach function space on R^(n).In this article,we introduce the weak Hardytype space WH_(X)(R^(n)),associated with X,via the radial maximal *** that the powered HardyLittlewood maximal operator satisfies some Fefferman-Stein vector-valued maximal inequality on X as well as it is bounded on both the weak ball quasi-Banach function space WX and the associated space,we then establish several real-variable characterizations of WH_(X)(R^(n)),respectively,in terms of various maximal functions,atoms and *** an application,we obtain the boundedness of Calderón-Zygmund operators from the Hardy space H_(X)(R^(n))to WH_(X)(Rn),which includes the critical *** these results are of wide ***,when X:=M^(q)_(p)(R^(n))(the Morrey space),X:=L^(p)(R^(n))(the mixed-norm Lebesgue space)and X:=(EΦq)t(Rn)(the Orlicz-slice space),which are all ball quasi-Banach function spaces rather than quasiBanach function spaces,all these results are even *** to the generality,more applications of these results are predictable.

关键词： ball quasi-Banach function space weak Hardy space Orlicz-slice space maximal function atom molecule Calderón-Zygmund operator

Controllable synthesis of metallic Bi from commercial Bi_2O_3 via one-pot solvothermal reduction method

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Chinese Journal of Chemical Engineering 2017年第9期25卷 1202-1206页

作者： Lei Yang yangyang zhang Hua Li Hezhou Liu State Key Laboratory of Metal Matrix Composites School of Materials Science and Engineering Shanghai Jiao Tong University

Metallic bismuth crystal is one important and interesting semimetal that has attracted great attention owing to its unique thermal and electrical properties. Herein, we report a facile, green, cost-effective and sustainable solvothermal process using ethanol, glycol, isopropanol, phenylcarbinol as solvent and commercial Bi_2O_3 as the starting material to produce high-purity metallic Bi with tunable morphologies on large scale. It is found that all alcohols are capable of reducing Bi_2O_3 to Bi and the reducibility of glycol is proved to be the strongest. The highest purity of the resultant Bi is calculated to be 99.74%. What's more, the morphology of final Bi particles is controllable by adding various types and concentrations of additives. As a consequence, our work lays the root for the large scale solvothermal production of high-purity Bi particles with various regular morphologies.

关键词： Solvothermal Alcohol Metal Morphology Bismuth Reduction

Optimal patching locations and orientations for maximum energy harvesting efficiency of ultrathin flexible piezoelectric devices mounted on heart surface

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Theoretical & Applied Mechanics Letters 2022年第3期12卷 178-183页

作者： yangyang zhang Ji Wang Chaofeng Lü Faculty of Mechanical Engineering and Mechanics Ningbo UniversityNingbo 315211China College of Civil Engineering and Architecture Soft Matter Research Centerand Key Laboratory of Soft Machines and Smart Devices of Zhejiang ProvinceZhejiang UniversityHangzhou 310058China

Flexible piezoelectric energy harvesters(PEHs)have gained lots of attention in recent years,because of their potential biomechanical applications,such as powering implantable *** in vivo animal experiments have demonstrated that the output power of a flexible PEH varies remarkably with patching orientations and locations,but the underlying mechanism remains unclear ***,an electromechanical model for a flexible PEH installed on a beating heart is proposed,and a concise relationship between the output power of the device and myocardium strain is *** results demonstrate that the patching orientations have a significant impact on the output power of the PEH,and the optimal patching orientations for all patching locations are approximately 15–20 degree for PEHs mounted on the left *** simple theoretical method provided here would be universally effective for choosing the optimal patching locations and orientations of flexible PEHs installed on a nonhomogeneous deformed surface.

关键词： Biomechanical energy harvester Flexible electronics Heart motion Myocardial strain

Application of Optically Stimulated Luminescence Technique in Exploring a Concealed Sandstone-type Uranium Deposit

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Acta Geologica Sinica(English Edition) 2022年第2期96卷 571-581页

作者： KANG Huan CHEN Yuelong XUE Guoliang ZHAO Junxiang zhang Na zhang yangyang State Key Laboratory of Earthquake Dynamics Institute of GeologyChina Earthquake AdministrationBeijing 100029China School of Earth Sciences and Resources China University of GeosciencesBeijing 100083China Key Laboratory of Digital Earth Science Aerospace Information Research InstituteChinese Academy of SciencesBeijing 100094China Key Laboratory of Crustal Dynamics Institute of Crustal DynamicsChina Earthquake AdministrationBeijing 100085China

Identifying ore-induced geochemical anomalies at the surface that indicate concealed deposits in buried areas remains a significant challenge in geochemical exploration. In this study, in order to trace the source of the geochemical anomalies, systematic luminescence intensity analyses were conducted on quartz grains from the Quaternary regolith at the Hadatu sandstone-type uranium deposit in the Erenhot Basin. The optically stimulated luminescence(OSL) ages were much older than the depositional ages of the Quaternary regolith. Moreover, quartz OSL ages were closely related to both borehole grades and sampling depths. Thus, the abnormal mineral OSL ages from near-surface sediments were ultimately controlled by the sandstone-type uranium deposits. This is identical to the rapid changes of quartz OSL ages(0.063 ka/cm) and equivalent doses(0.19 Gy/cm) with depths in a given sampling site. The instantaneous soil radon concentration was positively correlated with the quartz OSL apparent age, indicating their ore-induced origin and, as a result, their effectiveness in the exploration of concealed uranium deposits. Other parameters, including mobile-state uranium and;Po contents, were poorly correlated with quartz OSL ages and therefore should only be used with caution for geochemical exploration. This is the first time an attempt has been made to discriminate the ore-induced sources for different surface anomaly parameters, including instantaneous soil radon, mobile-state uranium and;Po contents for concealed sandstonetype uranium deposits.

关键词： OSL dating geochemical anomaly ore-induced anomaly concealed sandstone-type uranium deposit