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Analysis of crack initiation location and its influencing factors of fretting fatigue in aluminum alloy components

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Chinese Journal of Aeronautics 2022年第6期35卷 420-436页

作者： Jian WANG caizhi ZHOU School of Civil Engineering and Architecture Southwest University of Science and TechnologyMianyang 621010China Shock and Vibration of Engineering Materials and Structures Key Laboratory'of Sichuan Province Southwest University of Science and TechnologyMianyang 621010China Department of Mechanical Engineering University of South CarolinaColumbia 29208United States

To promote the development of fretting fatigue assessment and control technology for aircraft components,this paper uses the Crystal Plasticity Finite Element(CPFE)method and sub-modeling technology to study the Crack Initiation Location(CIL)of fretting fatigue in Aluminum Alloy(AA)*** effects of external excitations such as normal load,tangential load,and axial stress on the CIL are *** is found that the Most Likely Cracked(MLC)site revealed in a specimen and the CIL may always be consistent after a limited number of cyclic loadings,and they are both located at the hotspot on the contact surface or in the *** MLC site may also migrate from the hotspot on the contact surface to the hotspot in the subsurface with an increase of the cyclic number,and finally transform into a *** relationship between the MLC site and the CIL of fretting fatigue and its influencing factors have also been described,as well as the identification method of the CIL of fretting fatigue,which provide theoretical and technical supports for anti-fretting fatigue design of AA components in service.

关键词： Crack nucleation Crystal plasticity Equivalent plastic strain Fretting fatigue Hotspot

Acute and chronic excitotoxicity in ischemic stroke and late-onset Alzheimer's disease

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Neural Regeneration Research 2025年第7期20卷 1981-1988页

作者： Shan ping Yu Emily Choi Michael QJiang Ling Wei Department of Anesthesiology Emory University School of MedicineAtlantaGAUSA Center for Visual and Neurocognitive Rehabilitation Atlanta Veterans Affairs Medical CenterDecaturGAUSA

Stroke and Alzheimer's disease are common neurological disorders and often occur in the same *** comorbidity of the two neurological disorders represents a grave health threat to older *** review presents a brief background of the development of novel concepts and their clinical *** activity of glutamatergic N-methyl-D-aspartate receptors and N-methyl-D-aspartate receptor-mediated Ca^(2+)influx is critical for neuronal *** ischemic insult induces prompt and excessive glutamate release and drastic increases of intracellular Ca^(2+)mainly via N-methyl-D-aspartate receptors,particularly of those at the extrasynaptic *** Ca^(2+)-evoked neuronal cell death in the ischemic core is dominated by necrosis within a few hours and days known as acute ***,mild but sustained Ca^(2+)increases under neurodegenerative conditions such as in the distant penumbra of the ischemic brain and early stages of Alzheimer's disease are not immediately toxic,but gradually set off deteriorating Ca^(2+)-dependent signals and neuronal cell loss mostly because of activation of programmed cell death *** on the Ca^(2+)hypothesis of Alzheimer's disease and recent advances,this Ca^(2+)-activated“silent”degenerative excitotoxicity evolves from years to decades and is recognized as a unique slow and chronic *** N-methyl-D-aspartate receptor subunit GluN3A,primarily at the extrasynaptic site,serves as a gatekeeper for the N-methyl-D-aspartate receptor activity and is neuroprotective against both acute and chronic *** stroke and Alzheimer's disease,therefore,share an N-methyl-D-aspartate receptor-and Ca^(2+)-mediated mechanism,although with much different time *** is thus proposed that early interventions to control Ca^(2+)homeostasis at the preclinical stage are pivotal for individuals who are susceptible to sporadic late-onset Alzheimer's disease and Alzheimer's disease-related

关键词： Ca^(2+)hypothesis cognitive deficits hyperactivity late-onset Alzheimer's disease neurodegeneration N-methyl-D-aspartate receptors N-methyl-D-aspartate receptor subunits pathogenesis preventive treatment

Gut microbiota-astrocyte axis: new insights into age-related cognitive decline

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Neural Regeneration Research 2025年第4期20卷 990-1008页

作者： Lan Zhang Jingge Wei Xilei Liu Dai Li Xiaoqi Pang Fanglian Chen Hailong Cao ping Lei Haihe Laboratory of Cell Ecosystem Department of GeriatricsTianjin Medical University General HospitalTianjinChina Tianjin Geriatrics Institute Tianjin Medical University General HospitalTianjinChina Department of Gastroenterology and Hepatology Tianjin Medical University General HospitalNational Key Clinical SpecialtyTianjin Institute of Digestive DiseasesTianjin Key Laboratory of Digestive DiseasesTianjinChina Department of Urology Tianjin Medical University General HospitalTianjinChina Tianjin Neurological Institution Tianjin Medical University General HospitalTianjinChina

With the rapidly aging human population,age-related cognitive decline and dementia are becoming increasingly prevalent *** is considered the main risk factor for cognitive decline and acts through alterations in the composition of the gut microbiota,microbial metabolites,and the functions of *** microbiota–gut–brain axis has been the focus of multiple studies and is closely associated with cognitive *** article provides a comprehensive review of the specific changes that occur in the composition of the gut microbiota and microbial metabolites in older individuals and discusses how the aging of astrocytes and reactive astrocytosis are closely related to age-related cognitive decline and neurodegenerative *** article also summarizes the gut microbiota components that affect astrocyte function,mainly through the vagus nerve,immune responses,circadian rhythms,and microbial ***,this article summarizes the mechanism by which the gut microbiota–astrocyte axis plays a role in Alzheimer’s and Parkinson’s *** findings have revealed the critical role of the microbiota–astrocyte axis in age-related cognitive decline,aiding in a deeper understanding of potential gut microbiome-based adjuvant therapy strategies for this condition.

关键词： age aging Alzheimer’s disease astrocytes cognitive decline dementia gut microbiota gut–brain axis microbial metabolites neuroinflammation Parkinson’s disease

Structural Modal Parameter Recognition and Related Damage Identification Methods under Environmental Excitations: A Review

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Structural Durability & Health Monitoring 2025年第1期19卷 25-54页

作者： Chao Zhang Shang-Xi Lai Hua-ping Wang School of Civil Engineering and Mechanics Lanzhou UniversityLanzhou730000China Key Laboratory of Special Functional Materials and Structural Design Ministry of EducationLanzhou UniversityLanzhou730000China

Modal parameters can accurately characterize the structural dynamic properties and assess the physical state of the ***,it is particularly signiﬁcant to identify the structural modal parameters according to the monitoring data information in the structural health monitoring(SHM)system,so as to provide a scientiﬁc basis for structural damage identiﬁcation and dynamic model modiﬁ*** view of this,this paper reviews methods for identifying structural modal parameters under environmental excitation and brieﬂy describes how to identify structural damages based on the derived modal *** paper primarily introduces data-driven modal parameter recognition methods(e.g.,time-domain,frequency-domain,and time-frequency-domain methods,etc.),brieﬂy describes damage identiﬁcation methods based on the variations of modal parameters(e.g.,natural frequency,modal shapes,and curvature modal shapes,etc.)and modal validation methods(e.g.,Stability Diagram and Modal Assurance Criterion,etc.).The current status of the application of artiﬁcial intelligence(AI)methods in the direction of modal parameter recognition and damage identiﬁcation is further *** on the pre-vious analysis,the main development trends of structural modal parameter recognition and damage identiﬁcation methods are given to provide scientiﬁc references for the optimized design and functional upgrading of SHM systems.

关键词： Structural health monitoring data information modal parameters damage identiﬁcation AI method

A New Pterodactyloid Pterosaur from the Early Cretaceous of the Western Part of Liaoning Province, Northeastern China

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Acta Geologica Sinica(English Edition) 2016年第3期90卷 777-782页

作者： LU Junchang LIU Cunyu PAN Lijun SHEN caizhi Institute of Geology Chinese Academy of Geological Sciences Beijing 100037 China Beipiao Pterosaur Museum of China Beipiao County 122100 China

Pangupterus liui gen. et sp. nov. from the Jiufotang Formation of Sihedang, Lingyuan City, Liaoning Province is erected based on a nearly complete lower jaw. It is characterized by having a total of 36 slender curved teeth with sharp tips, forming a distinct fish-grabbing mechanism; the teeth are well-spaced and are circular in section; the length ratio of the mandibular symphysis to the whole jaw is 20%; and the ratio of the tooth root width to tooth length is 12%. Toothed pterosaurs make up about 56.3% of the pterosaur assemblage from the Jiufotang Formation, which indicates that toothed forms played a key role in the ecosystem.

关键词： Pterosauria Pangupterus Jiufotang Formation western Liaoning

绿色金融是否提高了地方政府对数字经济的注意力?--基于政策文本分析

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生态经济 2025年第1期41卷 106-113,131页

作者：黄平贵州商学院经济与金融学院贵州贵阳550000

在有限理性决策者的注意力稀缺性理论下,地方政策的变化取决于地方政府注意力的变动。反之,地方政府注意力是否取决于其他相关政策的变化?论文挖掘2019—2021年我国30个省级地方政府政策文本数据,用文本中词频反映地方政府在数字经济倾... 详细信息

在有限理性决策者的注意力稀缺性理论下,地方政策的变化取决于地方政府注意力的变动。反之,地方政府注意力是否取决于其他相关政策的变化?论文挖掘2019—2021年我国30个省级地方政府政策文本数据,用文本中词频反映地方政府在数字经济倾注的“注意力”,并应用fsQCA方法探究绿色金融发展是否引起地方政府向数字经济倾注高注意力。研究结论如下:(1)地方政府对数字经济注意力存在“南强北弱”的区域特征。(2)当绿色投资或绿色支持得到发展时,地方政府通过数字技术的应用帮助监测和评估环保项目的效果,实现环境保护、污染治理,助推地方政府向数字经济投入高注意力。(3)当绿色债券和绿色基金同时发展时,作为融资工具,能够有效帮助实体企业获取资金,助力“双碳”,但受公共物品特征影响,很难被反映在企业利润中。并且,绿色债券和绿色基金所应用到的数字手段有限,较难引起高注意力。(4)当绿色金融各个方面发展较弱时,仅绿色债券、绿色权益所能调动的数字技术是不足的,不会促进地方政府向数字经济投入更高注意力。总之,分析绿色金融是否助推地方政府向数字经济投入注意力,对于探索绿色金融和数字经济协同发展路径具有重要意义。

关键词：绿色金融数字经济注意力 fsQCA方法

Task space control of free-floating space robots using constrained adaptive RBF-NTSM

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Science China(Technological Sciences) 2014年第4期57卷 828-837页

作者： GUO ShengPeng LI DongXu MENG YunHe FAN caizhi College of Aerospace Science and Engineering National University of Defense Technology

Trajectory tracking control of space robots in task space is of great importance to space missions, which require on-orbit manipulations. This paper focuses on position and attitude tracking control of a tree-floating space robot in task space. Since nei- ther the nonlinear terms and parametric uncertainties of the dynamic model, nor the external disturbances are known, an adap- tive radial basis function network based nonsingular terminal sliding mode （RBF-NTSM） control method is presented. The proposed algorithm combines the nonlinear sliding manifold with the radial basis function to improve control performance. Moreover, in order to account for actuator physical constraints, a constrained adaptive RBF-NTSM, which employs a RBF network to compensate for the limited input is developed. The adaptive updating laws acquired by Lyapunov approach guar- antee the global stability of the control system and suppress chattering problems. Two examples are provided using a six-link free-floating space robot. Simulation results clearly demonstrate that the proposed constrained adaptive RBF-NTSM control method performs high precision task based on incomplete dynamic model of the space robots. In addition, the control errors converge faster and the chattering is eliminated comparing to traditional sliding mode control.

关键词： free-floating space robots task space radial basis function nonsingular terminal sliding mode

A promising approach for quantifying focal stroke modeling and assessing stroke progression:optical resolution photoacoustic microscopy photothrombosis

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Neural Regeneration Research 2025年第7期20卷 2029-2037页

作者： Xiao Liang Xingping Quan Xiaorui Geng Yujing Huang Yonghua Zhao Lei Xi Zhen Yuan ping Wang Bin Liu Faculty of Health Sciences University of MacaoMacao Special Administrative RegionChina Center for Cognitive and Brain Sciences University of MacaoMacao Special Administrative RegionChina Department of Biomedical Engineering Southern University of Science and TechnologyShenzhenGuangdong ProvinceChina State Key Laboratory of Quality Research in Chinese Medicine Institute of Chinese Medical SciencesUniversity of MacaoTaipaMacao Special Administrative RegionChina Department of Emergency Zhujiang HospitalSouthern Medical UniversityGuangzhouGuangdong ProvinceChina

To investigate the mechanisms underlying the onset and progression of ischemic stroke,some methods have been proposed that can simultaneously monitor and create embolisms in the animal cerebral ***,these methods often require complex systems and the effect of age on cerebral embolism has not been adequately studied,although ischemic stroke is strongly *** this study,we propose an optical-resolution photoacoustic microscopy-based visualized photothrombosis methodology to create and monitor ischemic stroke in mice simultaneously using a 532 nm pulsed *** observed the molding process in mice of different ages and presented age-dependent vascular embolism ***,we integrated optical coherence tomography angiography to investigate age-associated trends in cerebrovascular variability following a *** imaging data and quantitative analyses underscore the differential cerebrovascular responses to stroke in mice of different ages,thereby highlighting the technique's potential for evaluating cerebrovascular health and unraveling age-related mechanisms involved in ischemic strokes.

关键词： age-dependent cerebral cortex ischemic stroke mouse model optical coherence tomography angiography photoacoustic microscopy photothrombosis vascular imaging

Enhanced electrochemical CO_(2)reduction coupled with urea oxidation using bifunctional atomically dispersed CuNi catalysts

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Nano Research 2025年第1期18卷 208-216页

作者： Wenjie Wu Haoyang Zhou Ying Liu Yifei Pan Qingqing Chen Yu Zhang Junjie Mao Wenjie Ma ping Yu Beijing National Laboratory for Molecular Sciences Key Laboratory of Analytical Chemistry for Living BiosystemsInstitute of ChemistryChinese Academy of Sciences(CAS)Beijing 100190China College of Chemistry and Materials Science Anhui Normal UniversityWuhu 241002China University of Chinese Academy of Sciences Beijing 100049China

The electrochemical conversion of carbon dioxide(CO_(2))into chemical fuels represents a promising approach for addressing global carbon balance ***,this process is hindered by the kinetic limitations of anodic reactions,usually the oxygen evolution reaction,resulting in less efficient production of high value-added ***,we report an integrated electrocatalytic system that couples CO_(2)reduction reaction(CO_(2)RR)with urea oxidation reaction(UOR)using a bifunctional electrocatalyst with atomically dispersed dual-metal CuNi sites anchored on bamboo-like nitrogen-doped carbon nanotubes(CuNi-CNT),which were synthesized through a one-step pyrolysis *** bifunctional CuNi-CNT catalyst exhibits a near 100%CO Faraday efficiency for CO_(2)RR over a wide potential range and outstanding UOR performance with a negatively shifted potential of 210 mV at 10 mA·cm^(-2).In addition,we assemble a two-electrode electrolyzer using bifunctional CuNi-CNT-modified carbon fiber paper electrodes as both cathode and anode,capable of operating at a remarkably low cell voltage of 1.81 V at 10 mA·cm-2,significantly lower than conventional *** study provides a novel avenue to achieving an efficient carbon cycle with reduced electric power consumption.

关键词： electrochemical conversion bimetallic site catalyst bifunctional electrocatalyst carbon dioxide reduction urea oxidation