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A Novel Tensor Decomposition-Based Efficient Detector for Low-Altitude Aerial Objects With Knowledge Distillation Scheme

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IEEE/CAA journal of Automatica Sinica 2024年第2期11卷 487-501页

作者： Nianyin Zeng Xinyu li Peishu Wu Han li Xin Luo Department of Instrumental and Electrical Engineering Xiamen UniversityXiamen 361005China IEEE College of Computer and Information Science Southwest UniversityChongqing 400715China

Unmanned aerial vehicles(UAVs) have gained significant attention in practical applications, especially the low-altitude aerial(LAA) object detection imposes stringent requirements on recognition accuracy and computational resources. In this paper, the LAA images-oriented tensor decomposition and knowledge distillation-based network(TDKD-Net) is proposed,where the TT-format TD(tensor decomposition) and equalweighted response-based KD(knowledge distillation) methods are designed to minimize redundant parameters while ensuring comparable performance. Moreover, some robust network structures are developed, including the small object detection head and the dual-domain attention mechanism, which enable the model to leverage the learned knowledge from small-scale targets and selectively focus on salient features. Considering the imbalance of bounding box regression samples and the inaccuracy of regression geometric factors, the focal and efficient IoU(intersection of union) loss with optimal transport assignment(F-EIoU-OTA)mechanism is proposed to improve the detection accuracy. The proposed TDKD-Net is comprehensively evaluated through extensive experiments, and the results have demonstrated the effectiveness and superiority of the developed methods in comparison to other advanced detection algorithms, which also present high generalization and strong robustness. As a resource-efficient precise network, the complex detection of small and occluded LAA objects is also well addressed by TDKD-Net, which provides useful insights on handling imbalanced issues and realizing domain adaptation.

关键词： Attention mechanism knowledge distillation(KD) object detection tensor decomposition(TD) unmanned aerial vehicles(UAVs)

INVESTIGATION OF LASER BEAM WELDING PROCESS OF AZ61 MAGNESIUM-BASED ALLOY

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Acta Metallurgica Sinica(English Letters) 2006年第4期19卷 287-294页

作者： H.Y. Wang Z.j. li Industrial Center Shenzhen Polytechnic Shenzhen 518055 China

Laser welling process of AZ61 magnesium alloys is investigated using a special CO2 laser experimental system. The effect of processing parameters including laser power, welling speed, and protection gas flow at the top and bottom is researched. The results show that an ideal well bead can be formed by choosing the processing parameters properly. An optimized parameter range is obtained by a large number of experiments. Among them, laser power and welling speed are the two main parameters that determine the well width and dimensions. The protect gas flow rate has a slight effect on the well width, but it directly effects the surface color of the well. The test results for typical welds indicate that the microhardness and tensile strength of the well zone are better than that of the base metal A fine-grained well region has been observed and no obvious heat-affected zone is found. The well zone mainly consists of small α-Mg phase, （α ＋ Al12Mg17）, and other eutectic phases. The small grains and the eutectic phases in the joint are believed to play an important role in the increase of the strength of wells for AZ61 magnesium alloys.

关键词： magnesium alloy laser beam welding laser power welling speed

REAL-TIME FLOOD FORECASTING MODEliNG OF 1D UNSTEADY CHANNEL FLOW AND KALMAN FILTER

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journal of Hydrodynamics 2001年第1期13卷 64-69页

作者： li, Z.j. Weng, M.H. Coll. of Water Res. and Environ. Hohai Univ. Nanjing 210024 China

The model of 1D unsteady channel flow combined with the Kalman filter for real-time channel flood forecasting was attempted. The suitable upstream and downstream boundary conditions were suggested. The system equation was given by the linearization of the finite difference equations of the mass conservation and momentum equations as well as the boundary conditions. In the Kalman filter updating model, because the number of measurement variable is less than that of state-space variables, the measurement error covariance matrix could be estimated in real time through the innovation sequence, and the system error covariance matrix needs to be estimated preliminarily. A real example of flood forecasting in the Huaihe River was given to explain how the method works. The results show that the model is reasonable and effective.

关键词： Channel flow Computer simulation Kalman filtering Unsteady flow

Huangqin Decoction Delays Progress of Colitis-Associated Carcinogenesis by Regulating Nrf2/HO-1 Antioxidant Signal Pathwayin Mice

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Chinese journal of Integrative Medicine 2024年第2期30卷 135-142页

作者： GU li-mei li He-zhong GAO Lei li Hui WEI Lan-fu PAN Cheng-yu WU Ke-xuan TIAN Yao-zhou Department of Gastrointestinal Endoscopy Affiliated Hospital of Nanjing University of Chinese MedicineNanjing(210029)China Department of Gastroenterology Affiliated Hospital of Integrated Traditional Chinese and Western MedicineNanjing University of Chinese MedicineNanjing(210028)China School of Integrated Chinese and Western Medicine Nanjing University of Chinese MedicineNanjing(210023)China

Objective:To investigate the effect of Huangqin Decoction(HQD)on nuclear factor erythroid 2 related-factor 2(Nrf2)/heme oxygenase(HO-1)signaling pathway by inducing the colitis-associated carcinogenesis(CAC)model mice with azoxymethane(AOM)/dextran sodium sulfate(DSS).Methods:The chemical components of HQD were analyzed by liquid chromatography-quadrupole-time-of-flight mass spectrometry(LC-Q-TOF-MS/MS)to determine the molecular constituents of HQD.Totally 48 C57BL/6j mice were randomly divided into 6 groups by a random number table,including control,model(AOM/DSS),mesalazine(MS),low-,medium-,and high-dose HQD(HQD-L,HQD-M,and HQD-H)groups,8 mice in each group.Except for the control group,the mice in the other groups were intraperitoneally injected with AOM(10 mg/kg)and administrated with 2.5%DSS orally for 1 week every two weeks(totally 3 rounds of DSS)to construct a colitis-associated carcinogenesis mouse model.The mice in the HQD-L,HQD-M and HQD-H groups were given HQD by gavage at doses of 2.925,5.85,and 11.7 g/kg,respectively;the mice in the MS group was given a suspension of MS at a dose of 0.043 g/kg(totally 11 weeks).The serum levels of malondialdehyde(MDA)and superoxide dismutase(SOD)were measured by enzyme-linked immunosorbent assay.The mRNA and protein expression levels of Nrf2,HO-1,and inhibitory KELCH like ECH-related protein 1(Keap1)in colon tissue were detected by quantitative real-time PCR,immunohistochemistry,and Westem blot,respectively.Results:LC-Q-TOF-MS/MS analysis revealed that the chemical constituents of HQD include baicalin,paeoniflorin,and glycyrrhizic acid.Compared to the control group,significantly higher MDA levels and lower SOD levels were observed in the model group(P<0.05),whereas the expressions of Nrf2 and HO-1 were significantly decreased,and the expression of Keap1 increased(P<0.01).Compared with the model group,serum MDA level was decreased and SOD level was increased in the HQD-M,HQD-H and MS groups(P<0.05).Higher expressions of Nrf2 and HO-1 were observed in the HQD groups.Co

关键词： Huangqin Decoction colitis-associated carcinogenesis nuclear factor erythroid 2 related-factor 2/heme oxygenase signaling pathway oxidative stress Chinese medicine

Revealing the high-frequency attenuation mechanism of polyurea-matrix composites

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Acta Mechanica Sinica 2020年第1期36卷 130-142页

作者： j.Cheng Z.L.liu C.C.Luo T.li Z.j.li Y.Kang Z.Zhuang Applied Mechanics Laboratory School of Aerospace EngineeringTsinghua UniversityBeijing100084China Key Laboratory of Advanced Materials of Ministry of Education Department of Chemical EngineeringTsinghua UniversityBeijing100084China School of Materials Science and Engineering Tsinghua UniversityBeijing100084China

In this paper,a method for analyzing the high-frequency attenuation property of polyurea-matrix composites is developed by combining experimental,computational and theoretical approaches.First,the ultrasonic experimental platform is established by solving the difficulties of high-frequency ultrasonic testing as high-frequency signal distortion,insufficient driving voltage and sampling rate failure,to study the dynamic mechanical properties(1-5 MHz)of pure polyurea and polyurea-matrix composites.Then,the influences of composite parameters including the size and volume fraction of inclusions on wave attenuation performance under different frequencies are obtained and further verified by numerical simulations.Next,the contribution of inclusions to the wave attenuation performance is also theoretically analyzed.It is found that the increase of inclusion volume fraction and inclusion diameter will increase the attenuation coefficient of the composites.And the attenuation of composites with the inclusions of a 150-μm diameter and 30%as volume fraction can be 82%higher than pure matrix.This amplifying attenuation effect of inclusions is mainly attributed to the scattering effect,which is verified by comparing numerical and theoretical results.

关键词： Polyurea Viscoelastic Dynamic mechanical properties Ultrasound

Properties of oscillatory neuronal activity in the basal ganglia and thalamus in patients with Parkinson’s disease

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Translational Neurodegeneration 2018年第1期7卷 154-166页

作者： G.Du P.Zhuang M.Hallett Y.-Q.Zhang j.-Y.li Y.-j.li Beijing Institute of Functional Neurosurgery Xuanwu HospitalCapital Medical UniversityNo.45 Changchun StreetXicheng DistrictBeijing 100053China Human Motor Control Section Medical Neurology BranchNINDSNIHBethesdaMDUSA Center of Parkinson’s disease Beijing Institute for Brain DisordersBeijingChina Key Laboratory of Neurodegenerative Diseases(Capital Medical University) Ministry of EducationBeijingChina

Background:The cardinal features of Parkinson’s disease(PD)are bradykinesia,rigidity and rest tremor.Abnormal activity in the basal ganglia is predicted to underlie the mechanism of motor symptoms.This study aims to characterize properties of oscillatory activity in the basal ganglia and motor thalamus in patients with PD.Methods:Twenty-nine patients with PD who underwent bilateral or unilateral electrode implantation for subthalamic nucleus(STN)DBS(n=11),unilateral pallidotomy(n=9)and unilateral thalamotomy(n=9)were studied.Microelectrode recordings in the STN,globus pallidus internus(GPi)and ventral oral posterior/ventral intermediate of thalamus(Vop/Vim)were performed.Electromyography of the contralateral limbs was recorded.Single unit characteristics including interspike intervals were analyzed.Spectral and coherence analyses were assessed.Mean spontaneous firing rate(MSFR)of neurons was calculated.Analysis of variance and χ^(2) test were performed.Results:Of 76 STN neurons,39.5% were 4–6 Hz band oscillatory neurons and 28.9% were β frequency band(βFB)oscillatory neurons.The MSFR was 44.2±7.6 Hz.Of 62 GPi neurons,37.1% were 4–6 Hz band oscillatory neurons and 27.4% were βFB neurons.The MSFR was 80.9±9.6 Hz.Of 44 Vop neurons,65.9% were 4–6 Hz band oscillatory neurons and 9%were βFB neurons.The MSFR was 24.4±4.2 Hz.Of 30 Vim oscillatory neurons,70% were 4–6 Hz band oscillatory neurons and 13.3% were β FB neurons.The MSFR was 30.3±3.6 Hz.Further analysis indicated that proportion of βFB oscillatory neurons in STN and GPi was higher than that of similar neurons in the Vop and Vim(Plia play a critical role in generation of parkinsonism.β oscillatory activity is more prominent in basal ga

关键词： Parkinson’s disease Basal ganglia The subthalamic nucleus The globus pallidus internus The ventrolateral thalamus Oscillatory activity Microelectrode recordings

Efficient　and　Convenient　Procedures　forthe　Formation　and　cleavage　of　steroid　acetals　catalysed　by　montmorillonite　aite　K　10

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Chinese Chemical Letters 1996年第11期7卷 975-978页

作者： li T.S. li S.H. li j.T. li H.Z. Wu X.X. Department of Chemistry Hebei University Baoding 071002 Hebei Province

Acetalization of steroid ketones and cleavage of the acetals have ben carried out inexcellent yield under catalysis of montmorillonite K 10.

关键词： montmorillonite catalysed steroid cleavage Convenient

A MONTE CARLO SIMULATION OF SECONDARY ELECTRON AND BACKSCATTERED ELECTRON IMAGES IN SCANNING ELECTRON MICROSCOPY

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Acta Metallurgica Sinica(English Letters) 2005年第3期18卷 351-355页

作者： H.M.li Z.j.Ding HefeiNationalLaboratoryforPhysicalSciencesatMicroscaleandDepartmentofPhysics UniversityofScienceandTechnologyofChinaHefei230026China

A new parallel Monte Carlo simulation method of secondary electron (SE) and back scattered electron images (BSE) of scanning electron microscopy (SEM) for a com plex geometric structure has been developed. This paper describes briefly the si mulation method and the modification to the conventional sampling method for the step length. Example simulation results have been obtained for several artifici al structures.

关键词： Monte Carlo SEM secondary electrons backscattered electrons,

Exploring the Cation Regulation Mechanism for Interfacial Water Involved in the Hydrogen Evolution Reaction by In Situ Raman Spectroscopy

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Nano-Micro Letters 2024年第3期16卷 303-312页

作者： Xueqiu You Dongao Zhang Xia‑Guang Zhang Xiangyu li jing‑Hua Tian Yao‑Hui Wang jian‑Feng li School of Ocean Information Engineering Fujian Provincial Key Laboratory of Oceanic Information Perception and Intelligent ProcessingJimei UniversityXiamen 361021People’s Republic of China State Key Laboratory of Physical Chemistry of Solid Surfaces MOE Key Laboratory of Spectrochemical Analysis and InstrumentationiChEMCollege of Chemistry and Chemical EngineeringCollege of MaterialsCollege of EnergyXiamen UniversityXiamen 361005People’s Republic of China Key Laboratory of Green Chemical Media and Reactions Ministry of EducationCollaborative Innovation Center of Henan Province for Green Manufacturing of Fine ChemicalsCollege of Chemistry and Chemical EngineeringHenan Normal UniversityXinxiang 453007People’s Republic of China Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province(IKKEM) Xiamen 361005People’s Republic of China

Interfacial water molecules are the most important participants in the hydrogen evolution reaction(HER).Hence,understanding the behavior and role that interfacial water plays will ultimately reveal the HER mechanism.Unfortunately,investigating interfacial water is extremely challenging owing to the interference caused by bulk water molecules and complexity of the interfacial environment.Here,the behaviors of interfacial water in different cationic electrolytes on Pd surfaces were investigated by the electrochemistry,in situ core-shell nanostructure enhanced Raman spectroscopy and theoretical simulation techniques.Direct spectral evidence reveals a red shift in the frequency and a decrease in the intensity of interfacial water as the potential is shifted in the positively direction.When comparing the different cation electrolyte systems at a given potential,the frequency of the interfacial water peak increases in the specified order:li+justing the radius,valence,and concentration of cation to form the two-H down structure.This unique interfacial water structure will improve the charge transfer efficiency between the water and electrode further enhancing the HER performance.Therefore,local cation tuning strategies can be used to improve the HER performance by optimizing the interfacial water structure.

关键词： In situ Raman Interfacial water Hydrogen evolution reaction Cations