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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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O_(2) adsorption on Fe_(3)O_(4) (110) surface and effect of gangue element Al doping: combined study of binding experiment and ab initio molecular dynamics

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Journal of Iron and Steel Research International 2024年第4期31卷 810-827页

作者： zheng-jian Liu Hui-qing jiang Yao-zu Wang Jian-liang Zhang Hong-mei Qiao An-yang zheng Fang-yu Guo School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China School of Intelligence Science and Technology University of Science and Technology BeijingBeijing 100083China Beijing Shougang Co. Ltd.Qian'an 064404HebeiChina Department of Physics National University of Defense TechnologyChangsha 410128HunanChina

At high temperature,the chemical reaction mechanism at the interface of magnetite and the influence mechanism of gangue element Al on the oxidation performance of magnetite are not *** addition,due to the limitation of existing experimental equipment,it is difficult to clarify the interface reaction mechanism in the oxidation process and the influence mechanism of Al on the surface oxidation reaction of Fe_(3)O_(4) at an atomic scale at high *** surface oxidation reaction mechanism of magnetite and the influence mechanism of Al on the oxidation of magnetite were studied by experiments and AIMD(ab initio molecular dynamics).The experimental results show that the existence of Al_(2)O_(3) will reduce the initial oxidation temperature and comprehensive oxidation performance of *** AIMD results show that aluminum can accelerate the interface reaction rate of Fe_(3)O_(4) in the high-temperature oxidation atmosphere,but the strong Al-O binding ability is not conducive to the transfer of O atoms in the oxidation process.

关键词： Ironmaking Magnetite oxidation Interface reaction Adsorption-Gangue aluminum AIMD

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Lift system optimization for hover-capable flapping wing micro air vehicle

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Frontiers of Mechanical Engineering 2024年第3期19卷 61-75页

作者： Shengjie XIAO Yongqi SHI Zemin WANG Zhe NI Yuhang zheng Huichao DENG Xilun ding Department of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China Shenzhen International Graduate School Tsinghua UniversityShenzhen 518055China

A key challenge is using bionic mechanisms to enhance aerodynamic performance of hover-capable flapping wing micro air vehicle(FWMAV).This paper presented a new lift system with high lift and aerodynamic efficiency,which use a hummingbird as a bionic *** new lift system is able to effectively utilize the high lift mechanism of hummingbirds,and this study innovatively utilizes elastic energy storage elements and installs them at the wing root to help improve aerodynamic performance.A flapping angle of 154°is achieved through the optimization of the flapping mechanism *** optimized wing shape and parameters are obtained through experimental studies on the ***,the max net lift generated is 17.6%of the flapping wing vehicle’s ***,energy is stored and released periodically during the flapping cycle,by imitating the musculoskeletal system at the wing roots of hummingbirds,thereby improving the energy utilization rate of the FWMAV and reducing power consumption by 4.5%under the same ***,strength verification and modal analyses are conducted on the flapping mechanism,and the weight of the flapping mechanism is reduced through the analysis and testing of different *** results show that the lift system can generate a stable lift of 31.98 g with a wingspan of 175 mm,while the lift system weighs only 10.5 g,providing aerodynamic conditions suitable for high maneuverability flight of FWMAVs.

关键词： lift optimization flapping wing elastic energy hovering flapping mechanism

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Highly Aligned Graphene Aerogels for Multifunctional Composites

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Nano-Micro Letters 2024年第6期16卷 276-342页

作者： Ying Wu Chao An Yaru Guo Yangyang Zong Naisheng jiang Qingbin zheng Zhong‑Zhen Yu Beijing Advanced Innovation Center for Materials Genome Engineering School of Materials Science and EngineeringUniversity of Science and Technology BeijingBeijing 100083People’s Republic of China Institute of Materials Intelligent Technology Liaoning Academy of MaterialsShenyang 110004People’s Republic of China School of Science and Engineering The Chinese University of Hong KongShenzhenShenzhenGuangdong 518172People’s Republic of China State Key Laboratory of Organic‑Inorganic Composites College of Materials Science and EngineeringBeijing University of Chemical TechnologyBeijing 100029People’s Republic of China

Stemming from the unique in-plane honeycomb lattice structure and the sp^(2)hybridized carbon atoms bonded by exceptionally strong carbon–carbon bonds,graphene exhibits remarkable anisotropic electrical,mechanical,and thermal *** maximize the utilization of graphene’s in-plane properties,pre-constructed and aligned structures,such as oriented aerogels,films,and fibers,have been *** unique combination of aligned structure,high surface area,excellent electrical conductivity,mechanical stability,thermal conductivity,and porous nature of highly aligned graphene aerogels allows for tailored and enhanced performance in specific directions,enabling advancements in diverse *** review provides a comprehensive overview of recent advances in highly aligned graphene aerogels and their *** highlights the fabrication methods of aligned graphene aerogels and the optimization of alignment which can be estimated both qualitatively and *** oriented scaffolds endow graphene aerogels and their composites with anisotropic properties,showing enhanced electrical,mechanical,and thermal properties along the alignment at the sacrifice of the perpendicular *** review showcases remarkable properties and applications of aligned graphene aerogels and their composites,such as their suitability for electronics,environmental applications,thermal management,and energy *** and potential opportunities are proposed to offer new insights into prospects of this material.

关键词： Highly aligned graphene aerogels Quantitative characterization of alignment Multifunctional composites Anisotropic properties Multifunctional applications

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Implementation of gastrointestinal function protection in severe acute pancreatitis

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Hepatobiliary & Pancreatic Diseases International 2024年第5期23卷 521-522页

作者： Fu-zheng Tao Rong-Lin jiang Shui-Fang Jin Intensive Care Unit Taizhou Integrated Traditional Chinese and Western Medicine HospitalTaizhou 310075China Intensive Care Unit the First Affiliated Hospital of Zhejiang Chinese Medical University(Zhejiang Provincial Hospital of Chinese Medicine)Hangzhou 310006China

Severe acute pancreatitis(SAP)is a serious systemic disease associated with strong local inflammatory reactions and serious systemic pathophysiological disorders caused by trypsin *** with SAP are prone to exhibit gastrointestinal ***,gastrointestinal dysfunction further aggravates the systemic inflammatory response and metabolic abnormalities,resulting in a more critical condition of *** dysfunction is considered to be the“trigger”of multiple organ dysfunction syndrome[1].Thus,it is important to maintain gastrointestinal homeostasis in the treatment of SAP.

关键词： gastrointestinal pancreatitis acute

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A method for support stiffness failure identification in a steel spring floating slab track of urban railway: a case study in China

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第3期25卷 206-222页

作者： Junyuan zheng Caiyou ZHAO Duojia SHI Ping WANG Jian WANG Bolong jiang Xi SHENG Key Laboratoryof High-speed Railway Engineering Ministry of EducationSouthwest Jiaotong UniversityChengdu 60031China School of Civil Engineering Southwest Jiaotong UniversityChengdu 610031China 01 DYNA(Qingdao)Test&Data Co. Ltd.Qingdao 266000China Rail Transit Digital Construction and Measurement Technology National Engineering Research Center China Railway Design CorporationTianjin300308China Institute of Urban Smart Transportation&Safety Maintenance Shenzhen UniversityShenzhen 518060China

The extensive use of steel spring floating slab tracks has effectively addressed the challenge of alleviating the environmental vibrations induced by urban rail transit ***,under the combined action of train dynamic loads and complex environmental factors,problems,such as the fracture of steel spring vibration isolators and suspension vibrations induced by the uneven settlement of the base,often *** failure of isolator support stiffness is often hidden in its early stages and is challenging to identify by conventional detection *** the same time,it will aggravate the wheel-rail interaction,accelerate the deterioration of track structure,and even affect the driving *** study first establishes a detailed coupled train-floating slab track-foundation analytical *** the influence of the vibration isolator support stiffness failure on the dynamic indices of the floating slab track system response is analyzed.A set of defect identification methods that can detect the number of failed steel springs,severity of damage,and their location is ***,an intelligent monitoring system for support stiffness of floating slab track is built by combining the density-based spatial clustering of applications with noise algorithm and statistical data analysis and is applied to a rail line in southern *** a three-year monitoring campaign,a suspension failure and a fracture of a steel spring were each successfully detected and detailed failure information was *** investigation results were consistent with the damage identification *** repair,the track structure dynamic response returned to the average pre-damage level and further deterioration had been *** proposed damage identification methods and monitoring system provide an approach for intelligent identification of track structure support stiffness failures.

关键词： Floating slab track Support stiffness Detailed analytical model Failure identification Monitoring system

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Uncovering of the formation of rare earth texture and pseudo fiber bimodal microstructure in the high ductility Mg-2Gd-0.4Zr alloy during extrusion

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Journal of Materials Science & Technology 2024年第5期172卷 166-184页

作者： Tianxu zheng Yaobo Hu Chao Zhang Tianshuo Zhao Bin jiang Fusheng Pan Aitao Tang College of Materials Science and Engineering Chongqing UniversityChongqing400044China National Engineering Research Center for Magnesium Alloys Chongqing400044China School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai200240China

The aim of this research was to elucidate the underlying mechanism involved in the formation of rare earth(RE)texture and pseudo fiber bimodal microstructure in the high ductility Mg-2Gd-0.4Zr *** microstructure and texture evolution during the extrusion process were analyzed using various tech-niques,including optical microscopy(OM),scanning electron microscopy(SEM),electron backscatter diffraction(EBSD),and electron probe microanalysis(EPMA).The findings revealed that the RE texture in the extruded Mg-2Gd-0.4Zr alloy emerged during the dynamic recrystallization(DRX)process and was further strengthened during the subsequent static recrystallization and grain growth *** nu-cleation and growth of grains in the streamline region of Zr particles were delayed in comparison to other regions due to the pinning effect of Zr particles,ultimately resulting in the formation of pseudofiber bi-modal microstructure in the extruded Mg-2Gd-0.4Zr alloy.

关键词： Magnesium alloys Ductility Rare earth texture Bimodal microstructure

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The Performance of Downward Shortwave Radiation Products from Satellite and Reanalysis over the Transect of Zhongshan Station to Dome A, East Antarctica

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Advances in Atmospheric Sciences 2024年第8期41卷 1574-1588,1671-1675页

作者： Jiajia JIA Zhaoliang ZENG Wenqian ZHANG Xiangdong zheng Yaqiang WANG Minghu ding State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China

The downward shortwave radiation(DSR) is an important part of the Earth's energy balance, driving Earth's system's energy, water, and carbon cycles. Due to the harsh Antarctic environment, the accuracy of DSR derived from satellite and reanalysis has not been systematically evaluated over the transect of Zhongshan station to Dome A, East ***, this study aims to evaluate DSR reanalysis products(ERA5-Land, ERA5, MERRA-2) and satellite products(CERES and ICDR) in this area. The results indicate that DSR exhibits obvious monthly and seasonal variations, with higher values in summer than in winter. The ERA5-Land(ICDR) DSR product demonstrated the highest(lowest) accuracy,as evidenced by a correlation coefficient of 0.988(0.918), a root-mean-square error of 23.919(69.383) W m^(–2), a mean bias of –1.667(–28.223) W m^(–2) and a mean absolute error of 13.37(58.99) W m^(–2). The RMSE values for the ERA5-Land reanalysis product at seven stations, namely Zhongshan, Panda 100, Panda 300, Panda 400, Taishan, Panda 1100, and Kunlun, were 30.938, 29.447, 34.507, 29.110, 20.339, 17.267, and 14.700 W m^(-2), respectively;with corresponding bias values of 9.887, –12.159, –19.181, –15.519, –8.118, 6.297, and 3.482 W m^(–2). Regarding seasonality, ERA5-Land, ERA5,and MERRA-2 reanalysis products demonstrate higher accuracies during spring and summer, while ICDR products are least accurate in autumn. Cloud cover, water vapor, total ozone, and severe weather are the main factors affecting DSR. The error of DSR products is greatest in coastal areas(particularly at the Zhongshan station) and decreases towards the inland areas of Antarctica.

关键词： downward shortwave radiation East Antarctic reanalysis product satellite product validation

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Constructing extrinsic oxygen vacancy on the surface of photocatalyst as CO_(2)and electrons reservoirs to improve photocatalytic CO_(2)reduction activity

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Journal of Environmental Sciences 2024年第6期140卷 37-45页

作者： Zaiyong jiang Hao Li Zhimin Yuan zheng Wang Maohong Fan Wenkang Miao Hong He State Key Joint Laboratory of Environment Simulation and Pollution Control Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China School of Chemistry&Chemical Engineering and Environmental Engineering Weifang UniversityWeifangShandong 261061China Departments of Chemical and Petroleum Engineering University of WyomingLaramieWY 82071USA Materials Genome Institute Shanghai UniversityShanghai 200444China

Constructing own oxygen vacancies in the photocatalysts is a very promising method to improve their photocatalytic CO_(2)reduction ***,some catalysts have excellent stabilities,making it difficult for them to construct their own oxygen *** simplify the above difficulty of stable photocatalysts,constructing extrinsic oxygen vacancies on their surface as a novel idea is ***,a stable TiO_(2)nanosheet is chosen as a research object,we uniformly deposited BiOCl quantum dots on their surface via a simple adsorption-deposition *** is found that BiOCl quantum dots are able to simultaneously self-transform into defective BiOCl with many oxygen vacancies when the photocatalyst is performed photocatalytic CO_(2)*** extrinsic oxygen vacancies can act as“CO_(2)and photo-generated electrons reservoirs”to improve CO_(2)capture and accelerate the separation of photogenerated electrons and *** the above reasons,the modified TiO_(2)showed obvious enhancement of photocatalytic CO_(2)reduction compared to pristine TiO_(2)and *** work may open a new avenue to broaden the use of oxygen vacancies in the process of photocatalytic CO_(2)reduction.

关键词： Oxygen vacancy BiOCl Photocatalyst CO_(2)reduction TiO_(2)

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Ultra Reliable Load-Aware Connection Management(LACM)Algorithm in WIA-FA Systems

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China Communications 2024年第8期21卷 142-161页

作者： Liu Gang jiang Chunhao Ren Xiaochun Fan Pingzhi Liang Chengchao Ma zheng Southwest Jiaotong University Chengdu 611756China State Key Laboratory of Rail Transit Engineering Informatization(FSDI) Xi’an 710043China Chongqing University of Posts and Telecommunications Chongqing 400065China

The increasing demand for industrial automation and intelligence has put forward higher requirements for the reliability of industrial wireless communication *** an international standard based on 802.11,Wireless networks for Industrial Automation-Factory Automation(WIA-FA)greatly improves the reliability in factory automation scenarios by Time Division Multiple Access(TDMA).However,in ultra-dense WIA-FA networks with mobile users,the basic connection management mechanism is *** of the handover and resource management algorithms are all based on frequency division multiplexing,not suitable for the TDMA in the WIA-FA ***,we propose Load-aware Connection Management(LACM)algorithm to adjust the linkage and balance the load of access devices to avoid blocking and improve the reliability of the *** then we simulate the algorithm to find the optimal settings of the *** comparing with other existing algorithms,the result of the simulation proves that LACM is more efficient in reliability and maintains high reliability of more than 99.8%even in the ultra-dense moving scenario with 1500 field ***,this algorithm ensures that only a few signaling exchanges are required to ensure load bal-ancing,which is no more than 5 times,and less than half of the best state-of-the-art algorithm.

关键词： connection management load-aware multi-connectivity reliability retransmission WIAFA

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