检索结果-南通市图书馆

Numerical investigation and modeling of sweep effects on inlet flow field of axial compressor cascades

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2024年第2期37卷 296-308页

作者： Jiancheng zhang donghai JIN Xingmin GUI School of Energy and Power Engineering Beihang UniversityBeijing 100191China Jiangxi Research Institue of Beihang University Nanchang 330096China

Swept blades are widely utilized in transonic compressors/fans and provide high load,high through-flow,high efficiency,and adequate stall ***,there is limited quantitative research on the mechanism of the effect of swept blades on the flow field,resulting in a lack of direct quantitative guidance for the design and analysis of swept blades in fans/*** better understand this mechanism,this study employs a reduced-dimensional force equilibrium method to analyze more than 1500 swept cascades *** verify that circumferential fluctuation terms are responsible for inducing radial migration in the inlet airflow field of the swept blade,resulting in variations in the incidence angle and consequently leading to changes in the characteristics of the swept ***,a combination of simple functions and machine learning is utilized to model the circumferential fluctuation terms and quantify the sweep *** prediction accuracy of the model is high,with coefficient of determination greater than 0.95 on the test *** the model is applied in a meridional flow analysis program,the calculation accuracy of the program for the incidence angle is improved by 0.4°and 0.6°at the design and off-design conditions respectively,compensating for the program’s original ***,the model can also provide quantitative guidance for the design of swept blades,thereby reducing the number of design iterations and improving design efficiency.

关键词： Turbomachinery Sweep aerodynamics Quasi-3d method Incidence angle Circumferential fluctuation Machine learning

维普期刊数据库

Review on Security defense Technology Research in Edge Computing Environment

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Electronics 2024年第1期33卷 1-18页

作者： Ke SHANG Weizhen HE Shuai zhang National digital Switching System Engineering and Technological R&d Center

Edge computing, which achieves quick data processing by sinking data computing and storage to the network edge, has grown rapidly along with the Internet of things. The new network architecture of edge computing brings new security challenges. Based on this, this paper investigates the edge computing security literature published in recent years and summarizes and analyzes research work on edge computing security from different attack surfaces. We start with the definition and architecture of edge computing. From the attack surface between device and edge server, as well as on edge servers, the research describes the security threats and defense methods of edge computing. In addition, the cause of the attack and the pros and cons of defense methods is introduced. The challenges and future research directions of edge computing are given.

关键词： Cloud computing Systems architecture Computer architecture Network architecture data processing Security Servers

Advancements in Humanoid Robots: A Comprehensive Review and Future Prospects

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2024年第2期11卷 301-328页

作者： Yuchuang Tong Haotian Liu Zhengtao zhang IEEE CAS Engineering Laboratory for Intelligent Industrial Vision Institute of AutomationChinese Academy of SciencesBeijing 100190China School of Artificial Intelligence University of Chinese Academy of SciencesBeijing 100049China

This paper provides a comprehensive review of the current status, advancements, and future prospects of humanoid robots, highlighting their significance in driving the evolution of next-generation industries. By analyzing various research endeavors and key technologies, encompassing ontology structure,control and decision-making, and perception and interaction, a holistic overview of the current state of humanoid robot research is presented. Furthermore, emerging challenges in the field are identified, emphasizing the necessity for a deeper understanding of biological motion mechanisms, improved structural design,enhanced material applications, advanced drive and control methods, and efficient energy utilization. The integration of bionics, brain-inspired intelligence, mechanics, and control is underscored as a promising direction for the development of advanced humanoid robotic systems. This paper serves as an invaluable resource, offering insightful guidance to researchers in the field,while contributing to the ongoing evolution and potential of humanoid robots across diverse domains.

关键词： Future trends and challenges humanoid robots human-robot interaction key technologies potential applications

维普期刊数据库

The RFI Fast Mitigation Algorithm Based on Block LMS Filter

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2024年第1期24卷 265-272页

作者： Han Wu Hai-Long zhang Ya-Zhou zhang Jie Wang Xu du Ting zhang Xin-Chen Ye Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Radio Astronomy Chinese Academy of SciencesNanjing 210008China National Astronomical data Center Beijing 100101China

The radio telescope possesses high sensitivity and strong signal collection *** receiving celestial radiation signals,it also captures Radio Frequency Interferences(RFIs)introduced by human ***,as signals originating from sources other than the astronomical targets,significantly impacts the quality of astronomical *** paper presents an RFI fast mitigation algorithm based on block Least Mean Square(LMS)*** enhances the traditional adaptive LMS filter by grouping L adjacent time-sampled points into one block and applying the same filter coefficients for filtering within each *** transformation reduces multiplication calculations and enhances algorithm efficiency by leveraging the time-domain convolution *** algorithm is tested using baseband data from the Parkes 64 m radio telescope's pulsar observations and simulated *** results confirm the algorithm's effectiveness,as the pulsar profile after RFI mitigation closely matches the original pulsar profile.

关键词： methods:data analysis techniques:interferometric (stars:)pulsars:individual(J0437-4715)

维普期刊数据库

Printed Circuit Board (PCB) Surface Micro defect detection Model Based on Residual Network with Novel Attention Mechanism

在线全文

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2024年第1期78卷 915-933页

作者： Xinyu Hu defeng Kong Xiyang Liu Junwei zhang daode zhang School of Mechanical Engineering Hubei University of TechnologyWuhan430068Chain

Printed Circuit Board(PCB)surface tiny defect detection is a difficult task in the integrated circuit industry,especially since the detection of tiny defects on PCB boards with large-size complex circuits has become one of the *** improve the performance of PCB surface tiny defects detection,a PCB tiny defects detection model based on an improved attention residual network(YOLOX-AttResNet)is ***,the unsupervised clustering performance of the K-means algorithm is exploited to optimize the channel weights for subsequent operations by feeding the feature mapping into the SENet(Squeeze and Excitation Network)attention network;then the improved K-means-SENet network is fused with the directly mapped edges of the traditional ResNet network to form an augmented residual network(AttResNet);and finally,the AttResNet module is substituted for the traditional ResNet structure in the backbone feature extraction network of mainstream excellent detection models,thus improving the ability to extract small features from the backbone of the target detection *** results of ablation experiments on a PCB surface defect dataset show that AttResNet is a reliable and efficient *** Torify the performance of AttResNet for detecting small defects in large-size complex circuit images,a series of comparison experiments are further *** results show that the AttResNet module combines well with the five best existing target detection frameworks(YOLOv3,YOLOX,Faster R-CNN,Tdd-Net,Cascade R-CNN),and all the combined new models have improved detection accuracy compared to the original model,which suggests that the AttResNet module proposed in this paper can help the detection model to extract target *** them,the YOLOX-AttResNet model proposed in this paper performs the best,with the highest accuracy of 98.45% and the detection speed of 36 FPS(Frames Per Second),which meets the accuracy and real-time requirements for the detection of tiny defect

关键词： Neural networks deep learning ResNet small object feature extraction PCB surface defect detection

Vitamin d binding protein in psychiatric and neurological disorders:Implications for diagnosis and treatment

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Genes & diseases 2024年第5期11卷 324-334页

作者： Ling Li Bing Han Yan Kong Gaojia zhang Zhijun zhang Research Institution of Neuropsychiatry School of MedicineSoutheast UniversityNanjingJiangsu 210009China department of Neurology Affiliated Zhongda HospitalNanjingJiangsu 210009China department of Pharmacology Jiangsu Provincial Key Laboratory of Critical Care MedicineSchool of MedicineSoutheast UniversityNanjingJiangsu 210009China department of Biochemistry and Molecular Biology School of MedicineSoutheast UniversityNanjingJiangsu 210009China Brain Cognition and Brain disease Institute Department of Mental Health and Public HealthFaculty of Life and Health SciencesShenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhenGuangdong 518055China

Vitamin d binding protein(VdBP)serves as a key transporter protein responsible for binding and delivering vitamin d and its metabolites to target *** plays a crucial part in the inflammatory reaction following tissue damage and is engaged in actin *** research has shed light on its potential role in various diseases,leading to a growing interest in understanding the implications of VdBP in psychiatric and neurological *** purpose of this review was to provide a summary of the existing understanding regarding the involvement of VdBP in neurological and psychiatric *** examining the intricate interplay between VdBP and these disorders,this review contributes to a deeper understanding of underlying mechanisms and potential therapeutic *** gained from the study of VdBP could pave the way for novel strategies in the diagnosis,prognosis,and treatment of psychiatric and neurological disorders.

关键词： Neurological disorder Polymorphism Psychiatric disorder Structure Vitamin d binding protein

Scene 3-d Reconstruction System in Scattering Medium

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2024年第8期80卷 3405-3420页

作者： Zhuoyifan zhang Lu zhang LiangWang Haoming Wu School of Artificial Intelligence Beijing University of Posts and TelecommunicationsBeijing100876China School of Information and Communication Engineering Hainan UniversityHaikou570228China School of Computer Science and Technology Hainan UniversityHaikou570228China

Research on neural radiance fields for novel view synthesis has experienced explosive growth with the development of new models and *** NeRF(Neural Radiance Fields)algorithm,suitable for underwater scenes or scattering media,is also *** underwater 3d reconstruction systems still face challenges such as long training times and low rendering *** paper proposes an improved underwater 3d reconstruction system to achieve rapid and high-quality 3d ***,we enhance underwater videos captured by a monocular camera to correct the image quality degradation caused by the physical properties of the water medium and ensure consistency in enhancement across ***,we perform keyframe selection to optimize resource usage and reduce the impact of dynamic objects on the reconstruction *** pose estimation using COLMAP,the selected keyframes undergo 3d reconstruction using neural radiance fields(NeRF)based on multi-resolution hash encoding for model construction and *** terms of image enhancement,our method has been optimized in certain scenarios,demonstrating effectiveness in image enhancement and better continuity between consecutive frames of the same *** terms of 3d reconstruction,our method achieved a peak signal-to-noise ratio(PSNR)of 18.40 dB and a structural similarity(SSIM)of 0.6677,indicating a good balance between operational efficiency and reconstruction quality.

关键词： Underwater scene reconstruction image enhancement NeRF

All-inorganic nitrate electrolyte for high-performance lithium oxygen battery

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2024年第5期17卷 4163-4170页

作者： dongyue Yang Jiayi du Kai Chen Haoran zhang Gang Huang Tong Liu Xinbo zhang Hongjie zhang State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefei 230026China

Lithium-oxygen(Li-O_(2))batteries have been regarded as an expectant successor for next-generation energy storage systems owing to their ultra-high theoretical energy ***,the comprehensive properties of the commonly utilized organic salt electrolyte are still unsatisfactory,not to mention their expensive prices,which seriously hinders the practical production and application of Li-O_(2) ***,we have proposed a low-cost all-inorganic nitrate electrolyte(LiNO_(3)-KNO_(3)-dMSO)for Li-O_(2) *** inorganic nitrate electrolyte exhibits higher ionic conductivity and a wider electrochemical stability window than the organic salt *** existence of K+can stabilize the O_(2)-intermediate,promoting the discharge process through the solution pathway with an enlarged *** at an ultra-low concentration of 0.01 M,the K+can still remain stable to promote the solution discharge process and also possess a new function of inhibiting the dendrite growth by electrostatic shielding,further enhancing the battery stability and contributing to the long cycle *** a result,in the 0.99 M LiNO_(3)-0.01 M KNO_(3)-dMSO electrolyte,the Li-O_(2) batteries exhibit prolonged cycling performance(108 cycles)and excellent rate performance(2 A·g^(-1)),significantly superior to the organic salt one.

关键词： Li-O_(2)batteries potassium ions inorganic nitrate electrolyte solution pathway mechanism

Research on Performance Optimization of Spark distributed Computing Platform

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2024年第5期79卷 2833-2850页

作者： Qinlu He Fan zhang Genqing Bian Weiqi zhang Zhen Li School of Information and Control Engineering Xi’an University of Architecture and TechnologyXi’an710054China Shaanxi Institute of Metrology Science Xi’an710043China

Spark,a distributed computing platform,has rapidly developed in the field of big *** in-memory computing feature reduces disk read overhead and shortens data processing time,making it have broad application prospects in large-scale computing applications such as machine learning and image ***,the performance of the Spark platform still needs to be *** a large number of tasks are processed simultaneously,Spark’s cache replacementmechanismcannot identify high-value data partitions,resulting inmemory resources not being fully utilized and affecting the performance of the Spark *** address the problem that Spark’s default cache replacement algorithm cannot accurately evaluate high-value data partitions,firstly the weight influence factors of data partitions are modeled and ***,based on this weighted model,a cache replacement algorithm based on dynamic weighted data value is proposed,which takes into account hit rate and data *** integration and usage strategies are implemented based on LRU(LeastRecentlyUsed).Theweight update algorithm updates the weight value when the data partition information changes,accurately measuring the importance of the partition in the current job;the cache removal algorithm clears partitions without useful values in the cache to releasememory resources;the weight replacement algorithm combines partition weights and partition information to replace Rdd partitions when memory remaining space is ***,by setting up a Spark cluster environment,the algorithm proposed in this paper is experimentally *** have shown that this algorithmcan effectively improve cache hit rate,enhance the performance of the platform,and reduce job execution time by 7.61%compared to existing improved algorithms.

关键词： Spark memory optimization memory replacement strategy