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Design and Control of an Autonomous Bat-like Perching UAV

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Journal of Bionic Engineering 2024年第3期21卷 1253-1264页

作者： Long bai Wei Wang Xiaohong Chen Yuanxi Sun State Key Laboratory of Mechanical Transmission Chongqing UniversityChongqing400044China

Perching allows small Unmanned Aerial Vehicles(UAVs)to maintain their altitude while significantly extending their flight duration and reducing ***,current research on flying habitats is poorly adapted to unstructured environments,and lacks autonomous capabilities,requiring ideal experimental environments and remote control by *** solve these problems,in this paper,we propose a bat-like UAV perching mechanism by investigating the bat upside-down perching method,which realizes double self-locking in the perching state using the ratchet and four-link dead point *** on this perching mechanism,this study proposes a control strategy for UAVs to track targets and accomplish flight perching autonomously by combining a binocular camera,single-point LiDAR,and pressure *** perching experiments were conducted for crossbar-type objects *** experimental results show that a multirotor UAV equipped with the perching mechanism and sensors can reliably achieve autonomous flight perching and re-flying off the target *** power consumption is reduced to 2.9%of the hovering state when perched on the target object.

关键词： Bio-inspired design Perching mechanism UAV Autonomous flight

How to Construct a Lower Risk FOF Based on Correlation Network? The Method of Principal Component Risk Parity Asset Allocation

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Journal of Systems Science & Complexity 2024年第3期37卷 1052-1079页

作者： bai Wei ZHANG Junting LIU Haifei LIU Kai School of Management and Engineering Nanjing UniversityNanjing 210093China Postdoctoral Workstation of Bank of Jiangsu Co. LtdNanjing 210006China College of Finance Nanjing Agricultural UniversityNanjing 210095China University of Prince Edward Island 550 University AveCharlottetownPE C1A4P3Canada

In order to build a low-risk Fund of Funds(FOF), from the perspective of correlation, the principal component factor is used to improve the traditional risk parity model. Principal component analysis is used to decompose the underlying assets and generate unrelated principal component factors,and then the authors can construct a principal component risk parity portfolio. The proposed empirical results based on China’s mutual fund market show that the performance of principal component risk parity portfolio(PCRPP) is better than that of equal weight portfolio(EWP) and traditional risk parity portfolio(RPP). That is to say, not only the PCRPP in this paper has much lower risk than EWP and RPP, but also slightly better than EWP and RPP in terms of average return. Moreover, the study of dividing the underlying assets shows that the PCRPP in this paper is not sensitive to the underlying assets. The PCRPP in this paper is better than EWP and RPP for both the better performing funds and the worse performing funds. In addition, the empirical results on dynamic portfolio adjustments show that it is not appropriate to adjust asset allocation too frequently when the expected rate of return is calculated using the arithmetic mean.

关键词： Fund of funds(FOF) mutual funds portfolio risk principal component analysis risk parity portfolio

Effects of Number of Bleed Holes on Shock-Wave/Boundary-Layer Interactions in a Transonic Compressor Stator

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Journal of Thermal Science 2024年第2期33卷 611-624页

作者： LI bai ZHOU Xun luO Lei DU Wei School of Energy Science and Engineering Harbin Institute of TechnologyHarbin150001China

An extensive numerical investigation is conducted to characterize the flow separation control in a transonic compressor cascade with a porous *** bleed holes are arranged on the suction surface in a single row,two staggered rows and three staggered *** each bleed scheme,five bleed pressure ratios are examined at an inlet Mach number of *** results indicate that the aerodynamic performance of the cascade is significantly improved by the porous *** the single-row scheme,the maximum reduction in total pressure losses is 57%.For the two-staggered-row and three-staggered-row schemes,there is an optimal bleed pressure ratio of 1.0,and the maximum reductions in total pressure loss are 68% and 75%,*** low loss in the cascade is due to the well-controlled boundary *** new local supersonic region created by the bleed hole is the key reason for the improved boundary *** vortex induced by side bleeding provides another mechanism for delaying flow *** the bleed holes could create multiple local supersonic regions,which reduce the range of the adverse pressure gradient that the boundary layer needs to *** is the reason why cascades with more bleed holes perform better.

关键词： transonic compressor stator shock wave/boundary layer interaction porous bleed number of bleed holes

Spectrally resolved Franson interference

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Science China(Physics,Mechanics & Astronomy) 2024年第5期67卷 11-17页

作者： Rui-Bo Jin Zi-Qi Zeng Dan Xu Chen-Zhi Yuan bai-Hong Li You Wang Ryosuke Shimizu Masahiro Takeoka Mikio Fujiwara Masahide Sasaki Pei-Xiang lu Hubei Key Laboratory of Optical Information and Pattern Recognition Wuhan Institute of TechnologyWuhan 430205China School of Physics and Information Science Shaanxi University of Science and TechnologyXi'an 710021China Southwest Institute of Technical Physics Chengdu 610041China Graduate School of Informatics and Engineering University of Electro-CommunicationsTokyo 182-8585Japan Department of Electronics and Electrical Engineering Keio UniversityKanagawa 223-8522Japan national Institute of Information and Communications Technology Tokyo 184-8795Japan

Franson interference can be used to test the nonlocal features of energy-time entanglement and has become a standard in quantum ***,most of the previous Franson interference experiments were demonstrated in the time domain,and the spectral properties of Franson interference have not been fully ***,we theoretically and experimentally demonstrate spectrally resolved Franson interference using biphotons with different correlations,including positive correlation,negative correlation,and *** is found that the joint spectral intensities of the biphotons can be modulated along both the signal and idler directions,which has potential applications in generating high-dimensional frequency entanglement and time-frequency grid *** work may provide a new perspective for understanding the spectral-temporal properties of the Franson interferometer.

关键词： resolved correlation spectral

Temperature influence on minimum fluidization velocity:Complexity,mechanism,and solutions

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Particuology 2024年第5期88卷 344-349页

作者： Qingjin Zhang Liangliang Fu Guangwen Xu Dingrong bai Key Laboratory on Resources Chemicals and Material of Ministry of Education Shenyang University of Chemical TechnologyShenyang 110142China School of Materials Science and Engineering Shenyang University of TechnologyShenyang 110142China School of Chemical Engineering University of Science and Technology LiaoningAnshan 114051China

Fluidized-bed reactors are widely employed in various high-temperature industrial ***,it is crucial to understand the temperature effect on various fluidization phenomena,specifically the minimum fluidization velocity(U_(mf))that governs various aspects of fluidized bed *** this study,we comprehensively analyze U_(mf) data from the literature to unravel the complexity and underlying mechanisms of temperature influence on this critical *** research examines experimental data encompassing a wide range of temperatures,pressures,and solid *** analysis reveals that the influence of temperature on U_(mf) is fundamentally determined by the relative importance of hydrodynamic forces and interparticle forces within fluidized beds and is realized by three distinctive temperature-induced changes:gas properties,bed voidage,and physiochemical characteristics of *** this basis,an equation is derived to enable predictions of temperature influences on the minimum fluidization velocity under broad temperature conditions.

关键词： High-temperature gas-solids fluidized beds Minimum fluidization velocity Hydrodynamic forces Interparticle forces Bed voidage

Decouple charge transfer reactions in the Li-ion battery

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Journal of Energy Chemistry 2024年第5期92卷 759-798页

作者： Yuxuan bai Qiu-An Huang Kai Wu Jiujun Zhang Institute for Sustainable Energy/College of Sciences Shanghai UniversityShanghai 200444China Ningde Contemporary Innovation Laboratory Contemporary Amperex Technology Co.LimitedNingde 352100FujianChina

In the development of Li-ion batteries(LIBs)with high energy/power density,long cycle-life,fast charging,and high safety,an insight into charge transfer reactions is *** electrochemical impedance spectroscopy(EIS)is regarded as a powerful diagnosis tool,it is not a direct but an indirect *** respect to this,some critical questions need to be answered:(i)why EIS can reflect the kinetics of charge transfer reactions;(ii)what the inherent logical relationship between impedance models under different physical scenes is;(iii)how charge transfer reactions compete with each other at multiple *** work aims at answering these questions via developing a theory framework so as to mitigate the blindness and uncertainty in unveiling charge transfer reactions in *** systematically answer the above questions,this article is organized into a three-in-one(review,tutorial,and research)type and the following contributions are made:(i)a brief review is given for impedance model development of the LIBs over the past half century;(ii)an open source code toolbox is developed based on the unified impedance model;(iii)the competive mechanisms of charge transfer reactions are unveiled based on the developed EIS-Toolbox@*** work not only clarifies theoretical fundamentals,but also provides an easy-to-use open source code for EIS-Toolbox@LIB to optimize fast charge/discharge,mitigate cycle aging,and improve energy/power density.

关键词： Electrochemical impedance spectroscopy Unified impedance model Charge transfer reactions Solid/electrolyte diffusion Porous electrode EIS-Toolbox@LIB

The Influence of CO_(2) Cured Manganese Slag on the Performance and Mechanical Properties of Ultra-High Performance Concrete

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Fluid Dynamics & Materials Processing 2024年第8期20卷 1717-1730页

作者： Ligai bai Guihua Yang School of Architectural Engineering North China Institute of Aerospace EngineeringLangfang065000China

The presence of toxic elements in manganese slag(MSG)poses a threat to the environment due to potential *** CO_(2) curing on MS offers a promising approach to immobilize toxic substances within this material,thereby mitigating their release into the natural *** study investigates the impact of CO_(2) cured MS on various rheological parameters,including slump flow,plastic viscosity(η),and yield shear stress(τ).Additionally,it assesses flexural and compressive strengths(f_(t) and f_(cu)),drying shrinkage rates(DSR),durability indicators(chloride ion migration coefficient(CMC),carbonization depth(CD)),and the leaching behavior of heavy metal *** examination via scanning electron microscopy(SEM)is employed to elucidate the underlying *** results indicate that CO_(2) curing significantly enhances the slump flow of ultra-high performance concrete(UHPC)by up to 51.2%.Moreover,it reduces UHPC’sηandτby rates ranging from 0%to 52.7%and 0%to 40.2%,*** DSR exhibits a linear increase corresponding to the mass ratio of CO_(2) cured ***,CO_(2) curing enhances both f_(t) and f_(cu) of UHPC by up to 28.7%and 17.6%,*** electrical resistance is also improved,showing an increase of up to 53.7%.The relationship between mechanical strengths and electrical resistance follows a cubic *** CO_(2) cured MS demonstrates a notable decrease in the CMC and CD by rates ranging from 0%to 52.6%and 0%to 26.1%,*** reductions of leached chromium(Cr)and manganese(Mn)are up to 576.3%and 1312.7%,***,CO_(2) curing also enhances the compactness of UHPC,thereby demonstrating its potential to improve both mechanical and durability properties.

关键词： CO_(2)curing manganese slag steel fibers mechanical strengths salt action

The Uptake and Distribution Evidence of nano-and Microplastics in vivo after a Single High Dose of Oral Exposure

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Biomedical and Environmental Sciences 2024年第1期37卷 31-41页

作者： HONG Tao SUN Wei DENG Yuan LYU Jian Da JIN Cui Hong bai Ying Long na Jun ZHANG Rui GAO Yuan PAN Guo Wei YANG Zuo Sen YAN Ling Jun Research Center for Universal Health School of Public HealthChina Medical UniversityShenyang 110122LiaoningChina Department of Pain Management Shengjing Hospital of China Medical UniversityShenyang 110004LiaoningChina Department of Toxicology School of Public HealthChina Medical UniversityShenyang 110122LiaoningChina Department of Maternal and Child Health School of Public HealthChina Medical UniversityShenyang 110122LiaoningChina Institute of Preventive Medicine China Medical UniversityShenyang 110122LiaoningChina Institute of Chronic Diseases Liaoning Provincial Center for Disease Control and PreventionShenyang 110000LiaoningChina

Objective Tissue uptake and distribution of nano-/microplastics was studied at a single high dose by gavage in *** Fluorescent microspheres(100 nm,3μm,and 10μm)were given once at a dose of 200 mg/(kg∙body weight).The fluorescence intensity(FI)in observed organs was measured using the IVIS Spectrum at 0.5,1,2,and 4 h after *** was performed to corroborate these *** In the 100 nm group,the FI of the stomach and small intestine were highest at 0.5 h,and the FI of the large intestine,excrement,lung,kidney,liver,and skeletal muscles were highest at 4 h compared with the control group(Plung at 2 h(Pnano-/microplastics in tissues was further verified by *** peak time of nanoplastic absorption in blood was *** nanoplastics translocated rapidly to observed organs/tissues through blood circulation;however,only small amounts of MPs could penetrate the organs.

关键词： Microplastics nanoplastics IVIS Spectrum small-animal imaging system Tissue distribution Blood

GCAGA: A Gini Coefficient-Based Optimization Strategy for Computation Offloading in Multi-User-Multi-Edge MEC System

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Computers, Materials & Continua 2024年第6期79卷 5083-5103页

作者： Junqing bai Qiuchao Dai Yingying Li School of Computing Xi’an Shiyou UniversityXi’an710065China Product Center Wingtech Technology(Wuxi)Co.Wuxi214028China

To support the explosive growth of Information and Communications Technology(ICT),Mobile Edge Comput-ing(MEC)provides users with low latency and high bandwidth service by offloading computational tasks to the network’s ***,resource-constrained mobile devices still suffer from a capacity mismatch when faced with latency-sensitive and compute-intensive emerging *** address the difficulty of running computationally intensive applications on resource-constrained clients,a model of the computation offloading problem in a network consisting of multiple mobile users and edge cloud servers is studied in this *** a user benefit function EoU(Experience of Users)is proposed jointly considering energy consumption and time *** EoU maximization problem is decomposed into two steps,i.e.,resource allocation and offloading *** offloading decision is usually given by heuristic algorithms which are often faced with the challenge of slow convergence and poor ***,a combined offloading algorithm,i.e.,a Gini coefficient-based adaptive genetic algorithm(GCAGA),is proposed to alleviate the *** proposed algorithm optimizes the offloading decision by maximizing EoU and accelerates the convergence with the Gini *** simulation compares the proposed algorithm with the genetic algorithm(GA)and adaptive genetic algorithm(AGA).Experiment results show that the Gini coefficient and the adaptive heuristic operators can accelerate the convergence speed,and the proposed algorithm performs better in terms of convergence while obtaining higher *** simulation code of the proposed algorithm is available:https://***/Grox888/Mobile_Edge_Computing/tree/GCAGA.

关键词： Mobile edge computing multi-user-multi-edge joint optimization Gini coefficient adaptive genetic algorithm