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Chinese Journal of Aeronautics 2024年第6期37卷 20-37页

作者： Zhiyu li Kaiyuan ZHANG Zhigang li jun li Institute of Turbomachinery Xi’an Jiaotong UniversityXi’an 710049China

The mid-passage gap is an inevitable structure in a vane passage due to turbine vanes being manufactured *** coolant from this gap is able to prevent hot mainstream ingression and provide cooling protection for the endwall.A novel idea of enlarging the endwall’s coverage area and reducing the endwall’s thermal load by applying the mid-passage gap with variable surface angles is carried out in this *** endwall’s aerothermal and film cooling performances under four mid-passage gap modes at three typical mass flow ratio conditions are numerically *** indicate that under the traditional mid-passage mode,the coolant flows into the mainstream with a perpendicular incidence angle and can’t stick to the ***,cooling failure occurs,and the endwall’s thermal load is badly *** film cooling level at the suction-side endwall is improved when applying the mid-passage gap of a 45surface angle due to the secondary vortex being *** addition,when applying the mid-passage gap of a 135surface angle,the horseshoe vortex is pushed away,and the coverage area at the pressure-side endwall is enlarged *** best film cooling performance is achieved when the upstream surface angle is 135and the downstream surface angle is 45due to the adiabatic film cooling effectiveness being increased at both the pressure-and suction-side *** the mass flow ratio is 1.5%,the coverage area is enlarged by 43%,and the area-averaged adiabatic film cooling effectiveness is increased by 37%,when compared with those under the traditional mid-passage mode.

关键词： Film cooling Heat transfer Surface angle Mid-passagegap Turbinevane endwall

Mechanism of microarc oxidation on AZ91D Mg alloy induced byβ-Mg_(17)Al_(12) phase

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International Journal of Minerals,Metallurgy and Materials 2024年第4期31卷 712-724页

作者： Dajun Zhai Xiaoping li jun Shen College of Materials Science and engineering Chongqing UniversityChongqing 400044China

This work proposed a strategy of indirectly inducing uniform microarc discharge by controlling the content and distribution ofβ-Mg_(17)Al_(12)phase in AZ91D Mg *** kinds of nano-particles(ZrO_(2)and TiO_(2))were designed to be added into the substrate of Mg alloy by friction stir processing(FSP).Then,Mg alloy sample designed with different precipitated morphology ofβ-Mg_(17)Al_(12)phase was treated by microarc oxidation(MAO)in Na_(3)PO_(4)/*** characteristics and performance of the MAO coating was analyzed using scanning electron microscopy(SeM),energy dispersive spectrometer(eDS),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),contact angle meter,and potentiodynamic *** was found that the coarseα-Mg grains in extruded AZ91D Mg alloy were refined by FSP,and theβ-Mg_(17)Al_(12)phase with reticular structure was broken and *** nano-ZrO_(2)particles were pinned at the grain boundary by FSP,which refined theα-Mg grain and promoted the precipitation ofβ-Mg_(17)Al_(12)phase in *** effectively inhibited the“cascade”phenomenon of microarcs,which induced the uniform distribution of discharge *** MAO coating on Zr-FSP sample had good wettability and corrosion ***,TiO_(2)particles were hardly detected in the coating on TiFSP sample.

关键词： AZ91D Mg alloy microarc oxidation friction stir processing ZrO_(2) TiO_(2) β-Mg_(17)Al_(12)

Investigation on UV-curing Reprocessable Thermosets Bearing Hindered Urea Bonds and Their Composites with Modified Zinc Oxide Nanoparticles

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Chinese Journal of Polymer Science 2024年第6期42卷 751-765页

作者： jun-Hao Zhou li-Ming Tang Key Laboratory of Advanced Materials of Ministry of education of China Department of Chemical EngineeringTsinghua UniversityBeijing100084China

In this study,a series of hindered urea bond(HUB)containing polyurethane-urea methacrylate prepolymers and a none HUB containing polyurethane methacrylate prepolymer were prepared using isobornyl methacrylate as the reactive diluent via one-pot *** prepolymers were characterized fully by various ***,their thermosets were fabricated via UV curing in presence of a photo initiator,and their mechanical property and thermal behavior were investigated and *** from the none HUB containing thermoset,the HUB containing thermosets(defined as PUT)could be recycled and reprocessed by hot press under relatively mild conditions with high recovery ratio of mechanical ***,zinc oxide(ZnO)nanoparticles were modified with 3-(trimethoxysilyl)propyl methacrylate and the modified ZnO(defined as ZnO-TPM)was dispersed and polymerized into PUT matrix to prepare their *** influence of ZnO-TPM on the mechanical performance of the composites was evaluated,which indicated that the Young’s modulus and tensile strength increased gradually to the maximum values at ZnO-TPM content of 1 wt%and then *** composites also displayed good reprocessability with improved recovery ratio compared to the pure PUT *** addition,the composite materials exhibited strong UV absorption capacity,implying their potential application in the circumstance where UV-shielding was required.

关键词： Polyurethane-urea methacrylate Hindered urea bond ZnO nanoparticles Reprocessing UV curing

Prediction models of burst strength degradation for casing with considerations of both wear and corrosion

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Petroleum Science 2024年第1期21卷 458-474页

作者： Jie-li Wang Wen-jun Huang De-li Gao MOe Key Laboratory of Petroleum engineering China University of PetroleumBeijing102249China State Key Laboratory of Petroleum Resources and Prospecting China University of PetroleumBeijing102249China

Casing wear and casing corrosion are serious problems affecting casing integrity failure in deep and ultra-deep *** paper aims to predict the casing burst strength with considerations of both wear and ***,the crescent wear shape is simplified into three categories according to common mathematical ***,based on the mechano-electrochemical(M-e)interaction,the prediction model of corrosion depth is built with worn depth as the initial condition,and the prediction models of burst strength of the worn casing and corroded casing are ***,the accuracy of different prediction models is validated by numerical simulation,and the main influence factors on casing strength are *** last,the theoretical models are applied to an ultra-deep well in Northwest China,and the dangerous well sections caused by wear and corrosion are predicted,and the corrosion rate threshold to ensure the safety of casing is *** results show that the existence of wear defects results in a stress concentration and enhanced M-e interaction on corrosion depth *** accuracy of different mathematical models is different:the slot ring model is most accurate for predicting corrosion depth,and the eccentric model is most accurate for predicting the burst strength of corroded *** burst strength of the casing will be overestimated by more than one-third if the M-e interaction is neglected,so the coupling effect of wear and corrosion should be sufficiently considered in casing integrity evaluation.

关键词： Deep well Casing integrity Casing wear Casing corrosion Burst strength

An inulin-type fructan CP-A from Codonopsis pilosula attenuates experimental colitis in mice by promoting autophagy-mediated inactivation of NLRP3 inflammasome

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Chinese Journal of Natural Medicines 2024年第3期22卷 249-264页

作者： ZHOU Jiangtao WANG jun WANG Jiajing li Deyun HOU Jing li Jiankuan BAI Yun’e GAO Jianping School of Pharmaceutical Science Shanxi Medical UniversityJinzhong 030600China

Inulin-type fructan CP-A,a predominant polysaccharide in Codonopsis pilosula,demonstrates regulatory effects on immune activity and *** efficacy of CP-A in treating ulcerative colitis(UC)is,however,not *** study employed an in vitro lipopolysaccharide(LPS)-induced colonic epithelial cell model(NCM460)and an in vivo dextran sulfate sodium(DSS)-induced colitis mouse model to explore CP-A’s protective effects against experimental colitis and its underlying *** monitored the clinical symptoms in mice using various parameters:body weight,disease activity index(DAI),colon length,spleen weight,and histopathological ***,molecular markers were assessed through enzyme-linked immunosorbent assay(eliSA),quantitative real-time polymerase chain reaction(qRT-PCR),immunofluorescence(IF),immunohistochemistry(IHC),and Western blotting *** showed that CP-A significantly reduced reactive oxygen species(ROS),tumor necrosis factor-alpha(TNF-α),and interleukins(IL-6,IL-1β,IL-18)in LPS-induced cells while increasing IL-4 and IL-10 levels and enhancing the expression of Claudin-1,ZO-1,and occludin proteins in NCM460 ***,in vivo findings revealed that CPA administration markedly improved DAI,reduced colon shortening,and decreased the production of myeloperoxidase(MPO),malondialdehyde(MDA),ROS,IL-1β,IL-18,and NOD-like receptor protein 3(NLRP3)inflammasome-associated genes/proteins in UC ***-A treatment also elevated glutathione(GSH)and superoxide dismutase(SOD)levels,stimulated autophagy(LC3B,P62,Beclin-1,and ATG5),and reinforced Claudin-1 and ZO-1 expression,thereby aiding in intestinal epithelial barrier repair in colitis ***,the inhibition of autophagy via chloroquine(CQ)diminished CP-A’s protective impact against colitis in *** findings elucidate that CP-A’s therapeutic effect on experimental colitis possibly involves mitigating intestinal inflammation through autophagymediated N

关键词： Inulin-type fructan CP-A Codonopsis pilosula Ulcerative colitis NLRP3 inflammasome Autophagy

Camera,liDAR,and IMU Based Multi-Sensor Fusion SLAM:A Survey

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Tsinghua Science and Technology 2024年第2期29卷 415-429页

作者： jun Zhu Hongyi li Tao Zhang Department of Automation Tsinghua UniversityBeijing 100084China

In recent years,Simultaneous Localization And Mapping(SLAM)technology has prevailed in a wide range of applications,such as autonomous driving,intelligent robots,Augmented Reality(AR),and Virtual Reality(VR).Multi-sensor fusion using the most popular three types of sensors(e.g.,visual sensor,liDAR sensor,and IMU)is becoming ubiquitous in SLAM,in part because of the complementary sensing capabilities and the inevitable shortages(e.g.,low precision and long-term drift)of the stand-alone sensor in challenging *** this article,we survey thoroughly the research efforts taken in this field and strive to provide a concise but complete review of the related ***,a brief introduction of the state estimator formation in SLAM is ***,the state-of-the-art algorithms of different multi-sensor fusion algorithms are *** we analyze the deficiencies associated with the reviewed approaches and formulate some future research *** paper can be considered as a brief guide to newcomers and a comprehensive reference for experienced researchers and engineers to explore new interesting orientations.

关键词： multi-sensor fusion Simultaneous Localization And Mapping(SLAM) navigation localization

Deducing cascading failures caused by cyberattacks based on attack gains and cost principle in cyber-physical power systems

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Journal of Modern Power Systems and Clean energy 2019年第6期7卷 1450-1460页

作者： Yufei WANG Yanli liU jun’e li Key Laboratory of Aerospace Information Security and Trusted Computing Ministry of EducationSchool of Cyber Science and EngineeringWuhan UniversityWuhan 430072China Global energy Interconnection Research Institute Co.Ltd Beijing 102209China Key Laboratory of Smart Grid of Ministry of education Tianjin UniversityTianjin 300072China

To warn the cascading failures caused by cyberattacks(CFCAs)in real time and reduce their damage on cyber-physical power systems(CPPSs),a novel early warning method based on attack gains and cost principle(AGCP)is ***,according to the CFCA characteristics,the leading role of attackers in the whole evolutionary process is *** breaking out of a CFCA is deduced based on the AGCP from the view of attackers,and the priority order of all CFCAs is then ***,the method to calculate the probability of CFCAs is proposed,and an early warning model for CFCA is ***,to verify the effectiveness of this method,a variety of CFCAs are simulated in a local CPPS model based on the Ieee 39-bus *** experimental results demonstrate that this method can be used as a reliable assistant analysis technology to facilitate early warning of CFCAs.

关键词： Cyber-physical power system Cascading failure Cyberattack early warning Fault probability Attack gains and cost principle Attack route choice

Vision-based survey method for extraordinary loads on buildings

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Frontiers of Structural and Civil engineering 2024年第6期18卷 815-831页

作者： Yang li jun CHeN Pengcheng WANG College of Civil engineering Tongji UniversityShanghai 200092Chinab China United engineering Co.Ltd. Hangzhou 310052China State Key Laboratory of Disaster Reduction in Civil engineering Tongji UniversityShanghai 200092China Shanghai Key Laboratory of engineering Structure Safety Shanghai Research Institute of Building Sciences Co.Ltd.Shanghai 200032China

The statistical modeling of extraordinary loads on buildings has been stagnant for decades due to the laborious and error-prone nature of existing survey methods,such as questionnaires and verbal *** study proposes a new vision-based survey method for collecting extraordinary load data by automatically analyzing surveillance *** this purpose,a crowd head tracking framework is developed that integrates crowd head detection and reidentification models based on convolutional neural networks to obtain head trajectories of the crowd in the survey *** crowd head trajectories are then analyzed to extract crowd quantity and velocities,which are the essential factors for extraordinary *** survey areas with frequent crowd movements during temporary events,the equivalent dynamic load factor can be further estimated using crowd velocity to consider dynamic effects.A crowd quantity investigation experiment and a crowd walking experiment are conducted to validate the proposed survey *** experimental results prove that the proposed survey method is effective and accurate in collecting load data and reasonable in considering dynamic effects during extraordinary *** proposed survey method is easy to deploy and has the potential to collect substantial and reliable extraordinary load data for determining design load on buildings.

关键词： load survey extraordinary load live load object detection multiple-object tracking

Unraveling role of double-exchange interaction in electrochemical water oxidation by external magnetic field

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Rare Metals 2024年第1期43卷 289-297页

作者： jun li jun-Ming li Hong Hong Dong-Xue liu Qing-Qi Cao Dun-Hui Wang National Laboratory of Solid State Microstructures and Jiangsu Provincial Key Laboratory for Nanotechnology Nanjing UniversityNanjing 210093China School of electronics and Information Hangzhou Dianzi UniversityHangzhou 310018China

Double-exchange(De) interaction plays an important role in electrocatalytic oxygen evolution reaction(OeR).However,precise achievement of De interaction often requires foreign dopants or vacancy engineering,leading to destabilization of the catalysts and deterioration of *** contrast,the utilization of environmentally friendly,contactless,and continuously adjustable magnetic fields to study the OeR process is profitable to avoid aforementioned interference factors and further elucidate the direct relationship_(0.5)between De interaction and OeR ***,by using cobalt hydroxide carbonate(Co(OH)(CO_(3))·xH_(2)O,CoHC) nanostructures as a proof-of-concept study,external magnetic fields are carefully implemented to verify the role of De interaction during water oxidation *** studies reveal that external magnetic fields effectively enhance the reaction rate of the catalyst,the overpotential decreases from 386 to 355 mV(100 mA·cm^(-2)),while Tafel slopes drastically decline from 93 to 67 mV·dec^(-1)(1.0 T).Moreover,magnetic field increment exhibits robust *** in situ Raman and impedance measurements under external field,it can be found that magnetic field promotes the electron migration between Co^(2+) and Co^(3+) in the CoHC catalysts with the assistance of De interactions,thus boosting the OeR efficiency.

关键词： Magnetic field Double-exchange(De)interaction electrocatalysis Oxygen evolution reaction(OeR) Cobalt hydroxide carbonate

enhanced hydrogen evolution reaction in FePt film with remanence due to decrease in domain walls

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Rare Metals 2024年第3期43卷 1108-1115页

作者： Hong Hong Dong-Xue liu jun li jun-Ming li li-Qian Wu Bo Yang Qing-Qi Cao Dun-Hui Wang National Laboratory of Solid State Microstructures Collaborative Innovation Center of Advanced MicrostructuresJiangsu Provincial Key Laboratory for NanotechnologySchool of PhysicsNanjing UniversityNanjing210093China Hangzhou Dianzi University Hangzhou310018China Key Laboratory for Anisotropy and Texture of Materials(Ministry of education) School of Material Science and EngineeringNortheastern UniversityShenyang110819China

As an effective strategy to improve the properties of electrocatalysts,magnetic field-assisted electrocatalytic water splitting has attracted increasing attention ***,the corresponding enhancements mostly depend on the exertion of an external magnetic field during electrochemical reactions,which results in a high cost of industrial production,and makes the magnetic field manipulation of electrocatalysis become a challenging *** this work,instead of the external magnetic field,a bias magnetic field is self-supplied by the remanence state of a ferromagnetic electrocatalyst of *** to the assistance of this bias magnetic field,the FePt film in the remanence state shows the overpotential of 229 mV during hydrogen evolution reaction,which is much lower than that in its demagnetization state(283 mV).Our findings demonstrate that the remanence in ferromagnetic electrocatalysts can improve the catalytic performance,which is attributed to the decrease in domain walls.

关键词： Remanence Magnetic domains electrocatalysis Hydrogen evolution reaction(HeR)