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Autonomous navigation method of satellite constellation based on adaptive forgetting factors

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Chinese Journal of Aeronautics 2024年第7期37卷 317-332页

作者： Dong WANG Jing YANG Kai xiong School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China Science and Technology on Space Intelligent Control Laboratory Beijing Institute of Control EngineeringBeijing 100094China

To address the problem that model uncertainty and unknown time-varying system noise hinder the filtering accuracy of the autonomous navigation system of satellite constellation,an autonomous navigation method of satellite constellation based on the Unscented Kalman Filter with Adaptive Forgetting Factors(UKF-AFF)is *** process noise covariance matrix is estimated online with the strategy that combines covariance matching and adaptive adjustment of forgetting *** adaptive adjustment coefficient based on squared Mahalanobis distance of state residual is employed to achieve online regulation of forgetting factors,equipping this method with more *** intersatellite direction vector obtained from photographic observations is introduced to determine the constellation satellite orbit together with the distance measurement to avoid rank deficiency *** that the number of available measurements varies online with intersatellite visibility in practical applications such as time-varying constellation configurations,the smooth covariance matrix of state correction determined by innovation and gain is adopted and constructed *** analysis of the proposed method is also *** effectiveness of the proposed method is verified by the Monte Carlo simulation and comparison *** estimation accuracy of constellation position and velocity of UKF-AFF is improved by 30%and 44%respectively compared to those of the extended Kalman filter,and the method proposed is also better than other several adaptive filtering methods in the presence of significant model uncertainty.

关键词： Constellation autonomous navigation Unscented Kalman filter Adaptive forgetting factor Model uncertainty Stability analysis

Multi-Objective Multi-Variable Large-Size Fan Aerodynamic Optimization by Using Multi-Model Ensemble Optimization Algorithm

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Journal of Thermal Science 2024年第3期33卷 914-930页

作者： xiong Jin GUO Penghua LI Jingyin School of Energy and Power Engineering Xi’an Jiaotong UniversityXi’an710049China

The constrained multi-objective multi-variable optimization of fans usually needs a great deal of computational fluid dynamics(CFD)calculations and is *** this study,a new multi-model ensemble optimization algorithm is proposed to tackle such an expensive optimization *** multi-variable and multi-objective optimization are conducted with a new flexible multi-objective infill *** addition,the search direction is determined by the multi-model ensemble assisted evolutionary algorithm and the feature extraction by the principal component analysis is used to reduce the dimension of optimization ***,the proposed algorithm and other two optimization algorithms which prevail in fan optimizations were compared by using test *** the same number of objective function evaluations,the proposed algorithm shows a fast convergency rate on finding the optimal objective function ***,this algorithm was used to optimize the rotor and stator blades of a large axial fan,with the efficiencies as the objectives at three flow rates,the high,the design and the low flow ***-two variables were included in the optimization *** results show that compared with the prototype fan,the total pressure efficiencies of the optimized fan at the high,the design and the low flow rate were increased by 3.35%,3.07%and 2.89%,respectively,after CFD simulations for 500 fan candidates with the constraint for the design *** optimization results validate the effectiveness and feasibility of the proposed algorithm.

关键词： multi-objective optimization surrogate-assisted evolutionary algorithm axial fan computational fluid dynamics aerodynamic optimization

A wide-linear-range and low-hysteresis resistive strain sensor made of double-threaded conductive yarn for human movement detection

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Journal of Materials Science & Technology 2024年第5期172卷 202-212页

作者： Fei Huang Jiyong Hu xiong Yan Shanghai Frontier Science Research Center for Modern Textiles Donghua UniversityShanghai 201620China

Yarn-based flexible strain sensors with advantages in wearability and integrability have attracted wide ***,it is still a big challenge to achieve yarn-based strain sensors with a wide linear strain range,low hysteresis,and durability synchronously that can be used for full range detection of human body ***,a new structure,double-threaded conductive yarn with rhythmic strain distribu-tion,is reported to markedly widen the linear strain range of microcrack-based stretchable strain sensors.A new method of winding and thermally adhering hot-melt filaments on the surface of the elastic fiber is used to achieve double-threaded yarn(DTY)with rhythmic strain *** proposed strategy,the integration of heterogeneous materials,is reported to significantly reduce the mechanical hysteresis of composite *** strain distribution of the DTY during stretching causes multi-level micro-cracks in different regions of the carbon nanotube(CNT)conductive layer deposited on the surface of the ***,the sensing performance of DTY-based strain sensor can be adjusted by designing the structural *** final prepared flexible strain sensor has the advantages of a wide linear strain range(100%),great sensitivity(GF=12.43),low hysteresis,rapid response(158 ms),high repeatability(>2000 cycles at 50%strain),and hydrophobicity,*** sensor can monitor human motion repeatedly and stably well,and shows great advantages in flexible wearable devices.

关键词： Double-threaded yarn Strain redistribution Hysteresis Human motion monitoring

Effect of stress-relief annealing on thermal fatigue cracks for die-casting die steels

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Journal of Iron and Steel Research International 2024年第5期31卷 1164-1176页

作者： Zhi-xiong Bai Xiao-chun Wu School of Materials Science and Engineering Shanghai UniversityShanghai200444China

The effect of stress-relief annealing at different stages of thermal fatigue tests on crack growth was investigated using a self-built thermal cycle *** results showed that annealing could limit crack expansion *** reduced dislocation density and released the accumulation of residual *** addition,the strain accumulation in carbides was reduced by this *** was also found that double annealing was even more effective at inhibiting crack expansion compared to single stress-relief *** 1000 cycles,the maximum crack length was reduced by 31.1%and 45.2%for the samples after using the optimal single and double annealing processes,*** single stress-relief annealing,earlier annealing provides more benefit in delaying crack ***,effective double stress-relief annealing requires a suitable time interval between the annealing ***,after 800 cycles,surface hardness decreased significantly accompanied by an increase in the size and number of carbides,and cracks expanded predominantly along grain boundaries.

关键词： Thermal fatigue Steel Carbide Stress-relief annealing Dislocation Residual stress

Integrated Zoology’s collection of Wildlife Diseases Research Network

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Integrative Zoology 2024年第3期19卷 348-349页

作者： Wenhua xiong Institute of Zoology Chinese Academy of Sciences Office of the International Society of Zoological Sciences

The International Society of Zoological Sciences has developed a Wildlife Diseases Research Network(WDRN)in the world,with the collaboration of its partners such as the Working Group on Zoonotic Disease of the International Union of Biological Sciences(IUBS)(https://***/).WDRN is composed of a steering committee,a scientific committee,a research expert network,and collaborative partners.

关键词： partner committee IUB

An Example of Embedded Singular Continuous Spectrum for Discrete Schrödinger Operators

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Acta Mathematica Sinica,English Series 2024年第8期40卷 1837-1849页

作者： Zheng Qi FU xiong LI Laboratory of Mathematics and Complex Systems(Ministry of Education) School of Mathematical SciencesBeijing Normal UniversityBeijing 100875P.R.China

We present an example of a potential such that the corresponding discrete Schrödinger operator has singular continuous spectrum embedded in the absolutely continuous spectrum.

关键词： Sparse potentials singular continuous spectrum Prüfer variables

Multi-layer hierarchical cellulose nanofibers/carbon nanotubes/vinasse activated carbon composite materials for supercapacitors and electromagnetic interference shielding

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Nano Research 2024年第3期17卷 904-912页

作者： Tianxu Wang Chuanyin xiong Yongkang Zhang Bo Wang Qing xiong Mengjie Zhao Yonghao Ni College of Bioresources Chemical&Materials Engineering Shaanxi University of Science and TechnologyXi’an 710021China Department of Chemical and biomedical Engineering The University of MaineOronoME 04469USA University of New Brunswick Limerick Pulp&Paper CtrFrederictonNB E3B 5A3Canada

Developing porous self-supporting electrodes with excellent conductivity,good mechanical properties,and high electrochemical activity is crucial for constructing electrode materials with lightweight,ultra-thin,flexible,and high capacitance *** this work,we prepared a cellulose nanofibers(CNFs)/carbon nanotubes(CNTs)/vinasse activated carbon(VAC)(CCV)composite material with a multi-layer hierarchical conductive structure through simple vacuum filtration and *** this composite material,the self-assembly of CNF provides the main skeleton structure of a multi-layer hierarchical *** provides a fast path for the rapid transfer of electrons and is beneficial for the loss of electromagnetic *** provides sufficient double layer *** synergistic effect of the above three endows CCV composite materials with excellent energy storage performance and electromagnetic interference(EMI)shielding *** addition,we endowed the CCV composite with a certain shape and performance by introducing a vitrimer polymer with a dynamic cross-linked network *** summary,thanks to the synergistic effect of various components in the multi-layer hierarchical structure,CCV composite materials exhibit excellent integration performance,especially stable energy storage performance and EMI shielding *** significant properties make CCV composite materials have great application prospects in the fields of energy storage and intelligent EMI shielding.

关键词： self-supporting electrodes multi-layer hierarchical structure supercapacitors electromagnetic interference shielding

Probing the interseismic locking state of the Xianshuihe fault based on a viscoelastic deformation model

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Science China Earth Sciences 2024年第1期67卷 134-145页

作者： Yage ZHU Faqi DIAO Fei CHEN Yuebing WANG Zhigang SHAO Rongjiang WANG xiong xiong Hubei Subsurface Multi-Scale Imaging Key Laboratory School of Geophysics and GeomaticsChina University of GeosciencesWuhan 430074China China Earthquake Networks Center Beijing 100045China Institute of Earthquake Forecasting China Earthquake AdministrationBeijing 100036China

The interseismic locking state of tectonic faults is essential for regional seismic hazard ***,it is challenging to obtain this parameter reliably due to the weak deformation and complex model *** better probe the fault locking state,more reliable physical models and well-covered observations are *** we investigate the locking state of the Xianshuihe fault based on a new-developed viscoelastic deformation ***,we combine GPS velocities from 13 new near-field stations and existing stations in this region to improve the spatial *** to the theoretical predictions,our results indicate that the elastic model will clearly overestimate the fault locking depth and seismic moment accumulation rate,and the fault slip rate inferred from the elastic model is slightly lower than that from the viscoelastic *** on the locking distribution inferred from the viscoelastic model,we identify four potential asperities on the Xianshuihe *** importantly,we find a clear spatial correlation between the fault locking distribution and the rupture extent of historical earthquakes,which indicates that the fault locking state may control the rupture extent and thus the magnitude of *** addition,our results show that the 2022 M6.8 Luding earthquake only ruptured the south part of a potential asperity,and the accumulated energy in the northern unruptured area is equivalent to an Mw6.9 earthquake,where the seismic hazard deserves special attention.

关键词： Fault kinematics Viscoelastic relaxation effect GPS observations Seismic hazard The 2022 M6.8 Luding earthquake

Bilayer solid-electrolyte interphase structure enables a 440 Wh kg^(-1) lithium metal pouch cell to achieve 130 cycles

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Science China Chemistry 2024年第3期67卷 751-752页

作者： xiong Liu Chaojiang Niu School of Materials Science and Engineering Zhengzhou UniversityZhengzhou 450001China

Lithium(Li) metal has been considered one of the most promising anodes due to its high theoretical capacity, lightweight and low electrochemical potential. The cell-level energy density of rechargeable lithium metal batteries(LMBs) is expected to surpass 500 Wh kg^(-1) after replacing the graphite anode in lithium-ion batteries [1].

关键词： lithium electrolyte layer