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Low-frequency bandgap and vibration suppression mechanism of a novel square hierarchical honeycomb metamaterial

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Applied Mathematics and Mechanics(English Edition) 2024年第10期45卷 1841-1856页

作者： Xingjian DONG Shuo WANG Anshuai WANG Liang WANG Zhaozhan ZHANG Yuanhao TIE Qingyu LIN yongtao SUN State Key Laboratory of Mechanical Systems and Vibration Shanghai Jiao Tong UniversityShanghai 200240China Department of Mechanics Tianjin UniversityTianjin 300350China Tianjin Key Laboratory of Nonlinear Dynamics and Control Tianjin UniversityTianjin 300350China School of Mechanical and Automotive Engineering Guangxi University of Science and TechnologyLiuzhou 545006Guangxi Zhuang Autonomous RegionChina

The suppression of low-frequency vibration and noise has always been an important issue in a wide range of engineering *** address this concern,a novel square hierarchical honeycomb metamaterial capable of reducing low-frequency noise has been *** combining Bloch’s theorem with the finite element method,the band structure is *** results indicate that this metamaterial can produce multiple low-frequency bandgaps within 500 Hz,with a bandgap ratio exceeding 50%.The first bandgap spans from 169.57 Hz to 216.42 *** reveal the formation mechanism of the bandgap,a vibrational mode analysis is *** analysis demonstrates that the bandgap is attributed to the suppression of elastic wave propagation by the vibrations of the structure’s two protruding corners and overall expansion ***,detailed parametric analyses are conducted to investigate the effect ofθ,i.e.,the angle between the protruding corner of the structure and the horizontal direction,on the band structures and the total effective bandgap *** is found that reducingθis conducive to obtaining lower frequency *** propagation characteristics of elastic waves in the structure are explored by the group velocity,phase velocity,and wave propagation ***,the transmission characteristics of a finite periodic structure are investigated *** results indicate significant acceleration amplitude attenuation within the bandgap range,confirming the structure’s excellent low-frequency vibration suppression capability.

关键词： wave propagation vibration suppression metamaterial low-frequency bandgap

A General Framework for Intelligent IoT Data Acquisition and Sharing in an Untrusted Environment Based on Blockchain

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China Communications 2024年第3期21卷 137-148页

作者： Lu Yin Xue yongtao Li Qingyuan Wu Luocheng Li Taosen Yang Peipei Zhu Hongbo College of Internet of Things Nanjing University of Posts and TelecommunicationsNanjing 210003China Key Lab of Broadband Wireless Communication and Sensor Network Technology(Nanjing University of Posts and Telecommunications) Ministry of EducationNanjing 210003China Jiangsu Key Laboratory of Wireless Communications Nanjing University of Posts and TelecommunicationsNanjing 210003China Research Institute of Internet of Things Nanjing University of Posts and TelecommunicationsNanjing 210003China Bell Honors School Nanjing University of Posts and TelecommunicationsNanjing 210023China School of Automation Nanjing University of Posts and TelecommunicationsNanjing 210023China

Traditional Io T systems suffer from high equipment management costs and difficulty in trustworthy data sharing caused by *** provides a feasible research direction to solve these problems. The main challenge at this stage is to integrate the blockchain from the resourceconstrained Io T devices and ensure the data of Io T system is credible. We provide a general framework for intelligent Io T data acquisition and sharing in an untrusted environment based on the blockchain, where gateways become Oracles. A distributed Oracle network based on Byzantine Fault Tolerant algorithm is used to provide trusted data for the blockchain to make intelligent Io T data trustworthy. An aggregation contract is deployed to collect data from various Oracle and share the credible data to all on-chain users. We also propose a gateway data aggregation scheme based on the REST API event publishing/subscribing mechanism which uses SQL to achieve flexible data aggregation. The experimental results show that the proposed scheme can alleviate the problem of limited performance of Io T equipment, make data reliable, and meet the diverse data needs on the chain.

关键词： blockchain data sharing Internet of Things Oracle

Oxygenic iron clusters in ZSM-5 zeolite promote quantum sieving of gaseous hydrogen isotopes

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Science China Chemistry 2024年第4期67卷 1242-1249页

作者： Jingjing Zhang Yongyan Deng Dongxu Gai Yang Shi Xingwen Feng Peilong Li yongtao An Xiaoqin Zou Institute of Materials China Academy of Engineering PhysicsMianyang 621907China Faculty of Chemistry Northeast Normal UniversityChangchun 130024China

Isotopic separation is of paramount importance for producing high-purity heavy hydrogen,yet the process remains hugely ***,we report on an Fe/ZSM-5 zeolite that was able to efficiently separate deuterium from protium via chemical quantum *** data showed that four types of Fe species were present in Fe/ZSM-5 and oligomeric Fe-O clusters in the zeolite pores were correlated directly with gas *** adsorption revealed that Fe-O species served as the main adsorption sites and interacted with D_(2) more strongly than with H_(2).D_(2)/H_(2)separation was exemplified using thermal desorption spectroscopy.D_(2)/H_(2) selectivity increased with Fe loading in Fe/ZSM-5 and a selectivity of 32.1 was obtained with an optimal loading of 7 wt%.The shift of desorption temperature supports the chemical affinity-based quantum sieving of D_(2)over H_(2).This study demonstrates an effective strategy for enhancing D_(2)/H_(2) separation and the high selectivity means that Fe/ZSM-5 has strong potential in hydrogen isotope separation.

关键词： iron zeolite hydrogen isotope gas separation quantum sieving thermal desorption

Global modes and coupled modes for integrated twin circular-side octagon microlasers

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Science China(Information Sciences) 2022年第2期65卷 173-180页

作者： Ke YANG Yuede YANG Youzeng HAO Jiliang WU yongtao HUANG Jiachen LIU Jinlong XIAO Yongzhen HUANG State Key Laboratory of Integrated Optoelectronics Institute of Semiconductors Chinese Academy of Sciences Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences

Whispering-gallery mode(WGM) microlasers are potential light sources for photonic integrated circuits and optical information processing. In this paper, an integrated twin circular-side octagon microlaser(TCOM) composed of two identical circular-side octagon microcavities(COMs) is proposed and demonstrated for realizing lasing mode control. In a TCOM, we found a global mode with the mode field of an "8" pattern(labeled "8" mode) in addition to weak coupling modes of traditional four-bounce modes. The "8" mode belongs to the whole coupled cavity and is insensitive to the refractive index offset of coupled COMs, but the weak coupling modes are strongly sensitive to the refractive index offset. Lasing mode transformation from multiple coupled modes to a single "8" mode is demonstrated by adjusting the refractive index offset through injection currents. Weak coupling modes for directly connected TCOMs and lasing mode control make the COM a potential unit for large-scale photonic integration and optical information processing.

关键词： optical microcavity semiconductor lasers coupled cavity lasing mode control photonic integration

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Effect of electrokinetic property membrane on bovine serum of charged polyether sulfone albumin fouling behavior

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Frontiers of Environmental Science & Engineering 2017年第2期11卷 43-54页

作者： Xiaorong Meng Shanshan Huo Lei Wang Xudong Wang yongtao Lv Weiting tang Rui Miao Danxi Huang School of Science Xi'an University of Architecture and Technology Xi'an 710055 China School of Environmental & Municipal Engineering Xi'an University of Architecture and Technology Xi'an 710055 China

Negatively charged carboxymethylated polyethersulfone （CMPES） and positively charged quater- nized polyethersulfone （QAPES） ultrafiltration （UF） membranes were prepared by bulk chemical modification and non-solvent induced phase separation method. The effects of PES membrane interracial electrokinetic property on the bovine serum albumin （BSA） membrane fouling behavior were studied with the aid of the membrane-modified colloidal atomic force microscopy （AFM） probe. Electrokinetic test results indicated that the streaming potential （AE） of QAPES membrane was not consistent with its expected 1EC value, however, within the pH range of 3-10, the ζpotentials of two charged-modified PES membranes were more stable than the unmodified membrane. When pH value was 3, 4.7 or 9, the interaction behavior between charged PES membrane and BSA showed that there was significant linear correlation between the jump distance ro ofmembrane-BSA adhesion force （F/R） and the ~＂ potential absolute value. Charged modification significantly reduced the adhesion of PES membrane-BSA, and the adhesion data was good linear correlated with the flux decline rate in BSA filtration process, especially reflected in the CMPES membrane. The above experimental facts proved that the charged membrane interracial electric double layer structure and its electrokinetic property had strong ties with the protein membrane fouling behavior.

关键词： Charged PES UF membraneBSAElectrokinetic characterizationAdhesion forceJump distance

Comparison and Verification of Coherent Doppler Wind Lidar and Radiosonde Data in the Beijing Urban Area

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Advances in Atmospheric Sciences 2024年第11期41卷 2203-2214页

作者： Zexu LUO Xiaoquan SONG Jiaping YIN Zhichao BU Yubao CHEN yongtao YU Zhenlu ZHANG College of Marine Technology Faculty of Information Science and EngineeringOcean University of ChinaQingdao 266100China Laboratory for Regional Oceanography and Numerical Modeling Laoshan LaboratoryQingdao 266237China Qingdao Leice Transient Technology Co.LTD Qingdao 266100China CMA Meteorological Observation Centre Beijing 100081China Beijing Municipal Meteorological Observation Center Beijing 102600China Qingdao Meteorological Comprehensive Support Center Qingdao 266003China

As a new type of wind field detection equipment, coherent Doppler wind lidar(CDWL) still needs more relevant observation experiments to compare and verify whether it can achieve the accuracy and precision of traditional observation equipment in urban areas. In this experiment, a self-developed CDWL provided four months of observations in the southern Beijing area. After the data acquisition time and height match, the wind profile data obtained based on a Doppler beam swinging(DBS) five-beam inversion algorithm were compared with radiosonde data released from the same location. The standard deviation(SD) of wind speed is 0.8 m s^(–1), and the coefficient of determination R~2 is 0.95. The SD of the wind direction is 17.7° with an R~2 of 0.96. Below the height of the roughness sublayer(about 400 m), the error in wind speed and wind direction is significantly greater than the error above the height of the boundary layer(about 1500 m). For the case of wind speeds less than 4 m s^(–1), the error of wind direction is more significant and is affected by the distribution of surrounding buildings. Averaging at different height levels using suitable time windows can effectively reduce the effects of turbulence and thus reduce the error caused by the different measurement methods of the two devices.

关键词： coherent Doppler wind lidar radiosonde wind measurement urban boundary layer

Association between porpoise presence and fish choruses:implications for feeding strategies and ecosystem-based conservation of the East Asian finless porpoise

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Integrative Zoology 2023年第1期18卷 169-182页

作者： Zhaolong CHENG yongtao LI Matthew Keith PINE Tao ZUO Mingxiang NIU Jun WANG Yellow Sea Fisheries Research Institute Chinese Academy of Fishery SciencesQingdaoChina Laboratory for Marine Ecology and Environmental Science Pilot National Laboratory for Marine Science and Technology(Qingdao)QingdaoChina Department of Biology University of VictoriaVictoriaBritish ColumbiaCanada

The associations between feeding activities and environmental variables inform animal feeding tactics that max-imize energetic gains by minimizing energy costs while maximizing feeding *** studies in aquatic animals,particularly marine mammals,are scarce due to difﬁculties in the observation of feeding behaviors in aquatic *** data scarcity concurrently hinders ecosystem-basedﬁshery management in the context of small toothed-cetacean *** the present study,a passive acoustic monitoring station was deployed in an East Asianﬁnless porpoise habitat in Laizhou Bay to investigate potential relationships between East Asianﬁnless porpoises and their *** data revealed that porpoises were acoustically present nearly every day during the survey *** detection rates differed between spring and autumn in concert with activities ofﬁsh *** spring,ﬁsh choruses were present throughout the afternoon,and this was the time when porpoise vocalizations were the most frequently *** autumn,whenﬁsh choruses were absent,porpoise detec-tion rates decreased,and diurnal patterns were not *** close association betweenﬁsh choruses andﬁn-less porpoise activities implies an“eavesdropping”feeding strategy to maximize energetic gains,similar to other toothed cetaceans that are known to engage similar feeding *** noise pollution,particularly those maskingﬁsh choruses,could interruptﬁnless porpoises’feeding *** competing soniferousﬁshes withﬁnless porpoise could impactﬁnless porpoise viability through ecosystem disruption,in addition toﬁshing gear entanglement.

关键词： diel pattern noise andﬁshery management optimal foraging theory passive acoustic monitoring

Dense Sphene-type Solid Electrolyte Through Rapid Sintering for Solid-state Lithium Metal Battery

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Chemical Research in Chinese Universities 2020年第3期36卷 439-446页

作者： WANG yongtao GUO Xianwei LIN Zhivuan YANG Yubo WU Lingqiao LIU Huan YU Haijun College of Materials Science&Engineering Key Laboratory of Advanced Functional Materialshlinistty of EducationBeijing University of TechnologyBeijing 100124P.R.China

The sphene-type solid electrolyte with high ionic conductivity has been designed for solid-state lithium metal ***,the practical applications of solid electrolytes are still suffered by the low relative density and long sintering time of tens of hous with large energy ***,we introduced the spark plasma sintering technology for fabricating the sphene-type Li1.125Ta0.875Zr0.125SiO5 solid *** dense electrolyte pellet with high relative density of ca.97.4% and ionic conductivity of ca.1.44×10^-5S/cm at 30℃ can be obtained by spark plasma sintering process within the extremely short time of only *** the solid electrolyte provides stable electrochemical window of ca.6.0V(***^+/Li)and high electrochemical interface stability toward Li metal *** the enhanced interfacial contacts between electrodes and electrolyte pellet by the in-situ formed polymer electrolyte,the solid-state lithium metal battery with LiFePO4 cathode can deliver the initial discharge capacity of ca.154mA·h/g at 0.1C and the reversible capacity of ca.132mA·h/g after 70 cycles with high Coulombic efficienty of 99.5% at 55℃.Therefore,this study demonstrates a rapid and energy efficient sintering strategy for fabricating the solid electrolyte with dense structure and high ionic conductivity that can be practically applied in solid-state lithium metal batteries with high energy densities and safeties.

关键词： Solid-state lithium metal battery Sphene-type solid electrolyte Spark plasma sintering Dense structure Ionic conductivity

Relationships between modern pollen and vegetation and climate on the eastern Tibetan Plateau

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Research in Cold and Arid Regions 2023年第2期15卷 92-104页

作者： Lin Lin YunFa Miao yongtao Zhao Dong Yang Gen Wang College of Geography and Environmental Science Northwest Normal UniversityLanzhouGansu 730070China Key Laboratory of Oasis Resources Environment and Sustainable DevelopmentNorthwest Normal UniversityLanzhouGansu 730070China Key Laboratory of Desert and Desertification Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhouGansu 730000China Key Laboratory of Petroleum Resources Gansu Province/Key Laboratory of Petroleum Resources ResearchInstitute of Geology and GeophysicsChinese Academy of SciencesLanzhouGansu 73000China

The Tibetan Plateau ecosystem is fragile and sensitive to climate change. Understanding the relationships between modern pollen and the vegetation and climate of the region is critical for the evaluation of ecological ***, we explore modern pollen assemblages of typical land-cover types at a large spatial scale by analyzing 36surface samples from the southeastern Tibetan Plateau, supplemented by typical desert, desert-steppe, and steppe meadow transition data selected from the Chinese Surface Pollen Database, giving a total of 75 samples. We used redundancy analysis(RDA) to explore the responses of vegetation in the assemblages to regional climate. Our results show that pollen assemblages generally reflect the vegetation composition: assemblages from alpine meadow samples are dominated by Cyperaceae, Asteraceae, Rosaceae, and Polygonaceae;alpine shrublands mainly comprise Fabaceae, Rosaceae, Ericaceae, and Quercus(Q. spinosa);and coniferous forest surface samples mainly comprise Picea, Abies, Pinus, and Betulaceae. Our RDA shows that mean annual precipitation(MAP) is the main meteorological factor affecting the pollen assemblage and vegetation type;MAP positively correlates with percentages of Cyperaceae, Poaceae, Rosaceae, and Asteraceae, and negatively correlates with percentages of Chenopodiaceae, Ephedraceae, Nitraria, and Tamaricaceae. The ratio of Artemisia to Chenopodiaceae is a useful indicator to distinguish temperate desert from other land-cover types on the Tibetan Plateau, while the ratio of Cyperaceae + Asteraceae to Artemisia + Chenopodiaceae can be used to distinguish arid desert from other landcover types, and may provide a useful altitude index for the eastern Tibetan Plateau.

关键词： Surface pollen Tibetan Plateau Climate change Vegetation