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An uncertainty investigation for liner impedance eduction methods

Chinese Journal of Aeronautics 2024年第3期37卷 49-59页

作者： Weihao SHI Xiaodong jing School of Energy and Power Engineering Beihang UniversityBeijing 100191China

Impedance eduction methods have been developed for decades to meet the increasing need for high-quality impedance data in the design and optimization of acoustic *** this end,it is important to fully investigate the uncertainty problem,to which only limited attention has been devoted so *** paper considers the possibility of acoustically-induced structural vibration as a nonnegligible uncertainty or error source in impedance eduction *** the frequency moves away from the resonant frequency,with the increase in the value of cavity reactance,the acoustic particle velocity inside liner orifices possibly decreases to the extent comparable to the vibration velocity of liner facing ***,the acoustically-induced vibration,although generally being weak except at the inherent structural frequencies,may considerably affect the impedance eduction results near the anti-resonant frequency where the liner has poor *** demonstrate the effect of structural vibration,the vibration velocity of liner facing sheet is estimated from the experimentally educed admittance of the liner samples whose orifices are sealed with ***,a three-dimensional numerical model is set up,in which normal particle velocity is introduced over the solid portion of liner facing sheet to imitate structural vibration,rather than directly solving the acoustic-structural coupling *** shown by the results,the vibration of liner facing sheet,whose velocity is as small as estimated by the experiment,can result in anomalous deviation of the educed impedance from the impedance model near the anti-resonant *** trend that the anomalous deviation varies with frequency is numerically captured.

关键词： Impedance eduction Uncertainty analysis Acoustically-induced structural vibration Anti-resonant frequency Perforated liner

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DLF-YOLOF:an improved YOLOF-based surface defect detection for steel plate

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Journal of Iron and Steel Research International 2024年第2期31卷 442-451页

作者： Guang-hu Liu Mao-xiang Chu Rong-fen Gong Ze-hao Zheng School of Electronic and Information Engineering University of Science and Technology LiaoningAnshan114051LiaoningChina

Surface defects can affect the quality of steel *** methods based on computer vision are currently applied to surface defect detection of steel ***,their real-time performance and object detection of small defect are still *** improved object detection network based on You Only Look One-level Feature(YOLOF)is proposed to show excellent performance in surface defect detection of steel plate,called ***,the anchor-free detector is used to reduce the network ***,deformable convolution network and local spatial attention module are introduced into the feature extraction network to increase the contextual information in the feature ***,the soft non-maximum suppression is used to improve detection accuracy ***,data augmentation is performed for small defect objects during training to improve detection *** show the average precision and average precision for small objects are 42.7%and 33.5%at a detection speed of 62 frames per second on a single GPU,*** shows that DLF-YOLOF has excellent performance to meet the needs of industrial real-time detection.

关键词： Steel surface defects detection YOLOF Anchor-free detector Small object detection Real-time detection

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Effect of initial ammonium concentration on a one-stage partial nitrification/anammox biofilm system:Nitrogen removal performance and the microbial community

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Journal of Environmental Sciences 2024年第9期143卷 176-188页

作者： Mengyu Zhou Yun Han Yang Zhuo fen Yu Gaoyuan Hu Dangcong Peng School of Municipal and Environmental Engineering Xi’an University of Architecture and TechnologyXi’an 710055China Shaanxi Key Laboratory of Environmental Engineering Xi’an University of Architecture and TechnologyXi’an 710055China Key Laboratory of Northwest Water Resource Environment and EcologyMOEXi’an University of Architecture and TechnologyXi’an 710055China

One-stage partial nitrification coupled with anammox(PN/A)technology effectively reduces the energy consumption of a biological nitrogen removal *** nitrite-oxidizing bacteria(NOB)is essential for this technology to maintain efficient nitrogen removal *** ammonium concentration(IAC)affects the degree of inhibited *** this study,the effect of the IAC on a PN/A biofilm was investigated in a moving bed biofilm *** results showed that nitrogen removal efficiency decreased from 82.49%±1.90%to 64.57%±3.96%after the IAC was reduced from 60 to 20 mg N/L,while the nitrate production ratio increased from 13.87%±0.90%to 26.50%±3.76%.NOB activity increased to1,133.86 mg N/m^(2)/day after the IAC decreased,approximately 4-fold,indicating that the IAC plays an important inhibitory role in *** rate-limiting step in the mature biofilm of the PN/A system is the nitritation process and is not shifted by the *** analysis of the microbial community structure in the biofilm indicates that the IAC was the dominant factor in changes in community *** and *** were the main anammox bacteria,and Nitrosomonas and Nitrospira were the main AOB and NOB,*** did not affect the difference in growth between *** and ***,modulating the IAC promoted the PN/A process with efficient nitrogen removal performance at medium to low ammonium concentrations.

关键词： Biological nitrogen removal Partial nitrification Anammox Ammonium concentration Biofilm

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The dawn−dusk asymmetry in mesosphere and lower thermosphere temperature disturbances during geomagnetic storms at high latitude

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Earth and Planetary Physics 2024年第2期8卷 356-367页

作者： GuanChun Wei JianYong Lu fen Tang jingYuan Li Meng Sun Institute of Space Weather School of Atmospheric PhysicsNanjing University of Information Science&TechnologyNanjing 210044China College of Information and Communication National University of Defense TechnologyWuhan 430019China

Utilizing observations by the Sounding of the Atmosphere using Broadband Emission Radiometry(SABER)instrument,we quantitatively assessed the dawn-dusk asymmetry in temperature disturbances within the high-latitude mesosphere and lower thermosphere(MLT)during the main phase of geomagnetic storms in this *** analysis of five geomagnetic superstorm events indicated that during the main phase,negative temperature disturbances were more prevalent on the dawn side than on the dusk side in the high-latitude MLT *** of a statistical analysis of 54 geomagnetic storm events also revealed a notable disparity in temperature disturbances between the dawn and dusk *** high latitudes,38.2%of the observational points on the dawn side exhibited negative temperature disturbances(less than−5 K),whereas on the dusk side,this percentage was only 29.5%.In contrast,at mid-latitudes,these proportions were 34.1%and 36.5%,respectively,showing no significant *** also conducted a statistical analysis of temperature disturbances at different altitudes,which revealed an increase in the proportion of warming disturbances with ***,the proportion of cooling disturbances initially rose with altitude,reaching a peak around 105 km,and subsequently *** temperature disturbance differences could be explained by the day-night asymmetry in vertical wind disturbances during storm conditions.

关键词： dawn dusk asymmetry SABER(Sounding of the Atmosphere using Broadband Emission Radiometry) geomagnetic storms mesosphere and lower thermosphere

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A review on numerical studies of airflow dynamics and particle deposition in human respiratory system Author links open overlay panel

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Particuology 2024年第8期91卷 351-377页

作者： Hao jing Xinguang Cui School of Aerospace Engineering Huazhong University of Science and TechnologyWuhan430074China

Accurate assessment and prediction of airflow dynamics and particle deposition in the human respiratory tract are essential for human health,involving inhaled drugs for treating various diseases and toxic particles that can cause *** intricate process involves complex multiphase flow with distinct respiratory *** fluid dynamics(CFD)acts as a bridge,overcoming the limitations of in vivo and in vitro experiments and providing a means to fully comprehend and reveal the fundamental mechanisms of respiratory flow and particle behavior on a microscopic *** paper provides a comprehensive overview and concise summary of recent advancements in the numerical simulation of airflow and particle deposition in the human respiratory ***,it summarizes the transition of respiratory tract models from segmented models to emerging physiological characteristic models and whole-lung airway models,and the latest developments on the effects of key factors such as geometric variations,respiratory patterns,and particle physical/chemical properties on respiratory flow and particle deposition.A notable focus of this review is on emerging physiological characteristics models and their associated complex airflow and particle dynamics inside *** paper concludes with recommendations for future research to further advance the development of this field.

关键词： Airflow dynamics Particle deposition Human respiratory system Numerical modeling

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General formalism for dirty extreme-mass-ratio inspirals

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Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 22-29页

作者： ye Jiang Wen-Biao Han Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310024China Shanghai Frontiers Science Center for Gravitational Wave Detection Shanghai 200240China

Detecting the environment around the supermassive black holes and tests of general relativity are important applications of extreme-mass-ratio inspirals(EMRIs).There is still a challenge to efficiently describe various“dirty”impacts on the inspirals,such as dark matter,gas,dipole radiation,and electromagnetic *** this study,we find the inherent linearity of the asymptotic solution of the inhomogeneous Teukolsky *** the basis of this property,we completely decouple the factors of the perturber and the background spacetime in the energy fluxes and *** the new decoupling form,the waveforms of EMRIs with non-geodesic motion in Kerr spacetime can be conveniently *** will help to resolve the environment(including gas,field,dark matter,electromagnetic interaction)around supermassive black holes and test general relativity.

关键词： gravitational wave Teukolsky equation extreme-mass-ratio inspirals

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Enhancing the biological functionality of poly(lactic-co-glycolic acid)cage-like structures through surface modification with micro-and nano-sized hydroxyapatite particles

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Biosurface and Biotribology 2024年第2期10卷 63-75页

作者： Dongbiao Chang Siyu Li Zhenfan Bai jing You Lili Cao Qingcao Li Huan Tan Yan Zheng Feilun ye Jie Weng College of Medicine(Institute of Biomedical Engineering) Southwest Jiaotong UniversityChengduChina Key Laboratory of Advanced Technologies of Materials Ministry of Education School of Materials Science and EngineeringSouthwest Jiaotong UniversityChengduChina Medical Cosmetology Department Chengdu Third People's Hospital(Affiliated Hospital of Southwest Jiaotong University)ChengduChina

Biomaterials with exceptional performance are crucial for addressing the challenges of complex bone *** with traditional three-dimensional scaffolds,injectable microspheres enable new strategies for the treatment of irregular bone *** poly(lactic-co-glycolic acid)has found widespread applications as microcarriers of drugs,proteins,and other active *** to the surface of poly(lactic-co-glycolic acid)cage-like structures(PLGA-CAS),hydroxyapatite(HA)effectively reduces inflammation while enhancing biological *** this study,we loaded the surface of PLGA-CAS with micro-and nano-hydroxyapatite particles,referred to asμHA/PLGA-CAS and nHA/PLGA-CAS,***,their material characteristics and biological effects were *** incorporation of hydroxyapatite onto PLGA-CAS resulted in enhanced surface roughness and hydrophilicity,coupled with improved thermal stability and delayed ***,μHA/PLGACAS induced osteogenic differentiation of osteoblast precursor cells,while nHA/PLGACAS improved endothelial cell adhesion and stimulated angiogenic differentiation in ***,these findings suggest thatμHA/PLGA-CAS and nHA/PLGA-CAS,each with distinct characteristics,hold significant potential for application as microcarriers in various biomedical contexts.

关键词： biological functions hydroxyapatite material characteristics surface modification

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Robust adaptive radar beamforming based on iterative training sample selection using kurtosis of generalized inner product statistics

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Journal of Systems Engineering and Electronics 2024年第1期35卷 24-30页

作者： TIAN jing ZHANG Wei School of Information and Electronics Beijing Institute of TechnologyBeijing 100081China National Key Laboratory of Electromagnetic Space Security Chengdu 610036China

In engineering application,there is only one adaptive weights estimated by most of traditional early warning radars for adaptive interference suppression in a pulse reputation interval(PRI).Therefore,if the training samples used to calculate the weight vector does not contain the jamming,then the jamming cannot be removed by adaptive spatial *** the weight vector is constantly updated in the range dimension,the training data may contain target echo signals,resulting in signal cancellation *** cope with the situation that the training samples are contaminated by target signal,an iterative training sample selection method based on non-homogeneous detector(NHD)is proposed in this paper for updating the weight vector in entire range *** principle is presented,and the validity is proven by simulation results.

关键词： adaptive radar beamforming training sample selection non-homogeneous detector electronic jamming jamming suppression

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Biosafe,rapid,and ultrahigh-capacity endotoxin purification in blood by a sustainable and recyclable MOF-functionalized chitin microsphere adsorbent

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SusMat 2024年第5期4卷 163-177页

作者： Anxiong Liu Lu Chen Luhe Qi jing Huang Yongkang Zou Zhiwen Hu Le Yu Zibiao Zhong Qifa ye Chaoji Chen National Quality Control Center for Donated Organ Procurement Hubei Key Laboratory of Medical Technology on TransplantationHubei Clinical Research Center for Natural Polymer Biological LiverHubei Engineering Center of Natural Polymer-Based Medical MaterialsZhongnan Hospital of Wuhan UniversityInstitute of Hepatobiliary Diseases ofWuhan UniversityTransplant Center of Wuhan UniversityWuhanChina School of Resource and Environmental Science Hubei Biomass-Resource Chemistry and Environmental Biotechnology Key LaboratoryWuhan UniversityWuhanChina

Sepsis is responsible for approximately 5.3 million deaths globally each ***,we constructed hierarchical chitin microspheres loaded with MOF-919(Ch/metal–organic frameworks[MOFs])for the rapid and efficient removal of lipopolysaccharide(LPS)in complex blood ***,abun-dant active sites on MOF-919(Sc)also enable a record-high adsorption capacity of 9.56 mg/g in biomass-based adsorbents due to the coordination interactions between endotoxin and MOF-919(Sc).The LPS level of sepsis rabbits was less than 2 EU/mL(clearance rate>95%)after 90-min hemoperfusion,showing no adverse effect on the rabbit ***,compared to the commonly used LPS scrubber Toraymyxin(polymethyl methacrylate),the chitin adsorbent is significantly more cost-effective and environmentally *** prepara-tion strategy for hierarchical porous microspheres offers notable advantages in designability,recyclability,and renewability,providing a new approach to sepsis treatment and promising prospects for the biomedical application of sustainable biomass materials.

关键词： biomass blood purification chitin endotoxin removal hemoperfusion metal–organic frameworks

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Understanding the role of transition metal single-atom electronic structure in oxysulfur radical-mediated oxidative degradation

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Environmental Science and Ecotechnology 2024年第4期20卷 247-258页

作者： Guanshu Zhao jing Ding Jiayi Ren Qingliang Zhao Chengliang Mao Kun Wang Jessica ye Xueqi Chen Xianjie Wang Mingce Long State Key Laboratory of Urban Water Resources and Environment School of EnvironmentHarbin Institute of TechnologyHarbin150090China Solar Fuels Group Department of ChemistryUniversity of Toronto80 St.George StreetTorontoOntarioM5S 3H6Canada School of Physics Harbin Institute of TechnologyHarbin150001China School of Environmental Science and Engineering Key Laboratory of Thin Film and Microfabrication Technology(Ministry of Education)Shanghai Jiao Tong University800 Dongchuan RoadShanghai200240China

The ubiquity of refractory organic matter in aquatic environments necessitates innovative removal *** radical-based advanced oxidation has emerged as an attractive solution,offering high selectivity,enduring efficacy,and anti-interference *** many technologies,sulfite activation,leveraging its cost-effectiveness and lower toxicity compared to conventional persulfates,stands ***,the activation process often relies on transition metals,suffering from low atom *** we introduce a series of single-atom catalysts(SACs)employing transition metals on g-C_(3)N_(4)substrates,effectively activating sulfite for acetaminophen *** highlight the superior performance of Fe/CN,which demonstrates a degradation rate constant significantly surpassing those of Ni/CN and Cu/*** investigation into the electronic and spin polarization characteristics of these catalysts reveals their critical role in catalytic efficiency,with oxysulfur radical-mediated reactions ***,under visible light,the catalytic activity is enhanced,attributed to an increased generation of oxysulfur radicals and a strengthened electron donation-back donation *** proximity of Fe/CN's d-band center to the Fermi level,alongside its high spin polarization,is shown to improve sulfite adsorption and reduce the HOMO-LUMO gap,thereby accelerating photo-assisted sulfite *** work advances the understanding of SACs in environmental applications and lays the groundwork for future water treatment technologies.

关键词： Single-atom catalysts(SACs) Oxysulfur radical Sulfite activation Spin polarization Electronic structure

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