检索结果-南通市图书馆

Nitrogen‑Doped Magnetic‑Dielectric‑Carbon Aerogel for High‑Efficiency Electromagnetic Wave Absorption

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Nano-Micro Letters 2024年第1期16卷 313-327页

作者： Shijie Wang Xue Zhang Shuyan Hao Jing Qiao Zhou Wang Lili Wu Jiurong Liu Fenglong Wang key laboratory for Liquid‑Solid Structural Evolution and processing of Materials Ministry of Education Shandong UniversityJinan 250061People’s Republic of China School of Mechanical Engineering Shandong UniversityJinan 250061People’s Republic of China Shenzhen Research Institute of Shandong University Shenzhen 518057GuangdongPeople’s Republic of China

Carbonbased aerogels derived from biomass chitosan are encountering a flourishing moment in electromagnetic protection on account of lightweight,controllable fabrication and ***,developing a facile construction method of component design with carbon-based aerogels for high-efficiency electromagnetic wave absorption(EWA)materials with a broad effective absorption bandwidth(EAB)and strong absorption yet hits some ***,the nitrogen-doped magnetic-dielectric-carbon aerogel was obtained via ice template method followed by carbonization treatment,homogeneous and abundant nickel(Ni)and manganese oxide(MnO)particles in situ grew on the carbon *** to the optimization of impedance matching of dielectric/magnetic components to carbon aerogels,the nitrogen-doped magnetic-dielectric-carbon aerogel(Ni/MnO-CA)suggests a praiseworthy EWA performance,with an ultra-wide EAB of 7.36 GHz and a minimum reflection loss(RLmin)of−64.09 dB,while achieving a specific reflection loss of−253.32 dB mm−***,the aerogel reveals excellent radar stealth,infrared stealth,and thermal management ***,the high-performance,easy fabricated and multifunctional nickel/manganese oxide/carbon aerogels have broad application aspects for electromagnetic protection,electronic devices and aerospace.

关键词： Electromagnetic wave absorption Wide bandwidth Dielectric-magnetic synergy Multifunction

Fast measurement and prediction method for electromagnetic susceptibility of receiver

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2024年第2期35卷 275-285页

作者： CHEN Yan LU Zhonghao LIU Yunxia State key laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System College of Electronic Science and TechnologyNational University of Defense TechnologyChangsha 410073China State key laboratory of Astronautic Dynamics Xi’an 710043China

Aiming at evaluating and predicting rapidly and accurately a high sensitivity receiver’s adaptability in complex electromagnetic environments,a novel testing and prediction method based on dual-channel multi-frequency is proposed to improve the traditional two-tone ***,two signal generators are used to generate signals at the radio frequency(RF)by frequency scanning,and then a rapid measurement at the intermediate frequency(IF)output port is carried out to obtain a huge amount of sample data for the subsequent ***,the IF output response data are modeled and analyzed to construct the linear and nonlinear response constraint equations in the frequency domain and prediction models in the power domain,which provide the theoretical criteria for interpreting and predicting electromagnetic susceptibility(EMS)of the *** experiment performed on a radar receiver confirms the reliability of the method proposed in this *** shows that the interference of each harmonic frequency and each order to the receiver can be identified and predicted with the sensitivity *** on this,fast and comprehensive evaluation and prediction of the receiver’s EMS in complex environment can be efficiently realized.

关键词： electromagnetic susceptibility(EMS) receiver dualchannel multi-frequency nonlinear response frequency domain power domain

Ambiguity function analysis and side peaks suppression of Link16 signal based passive radar

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2023年第6期34卷 1526-1536页

作者： BAI Luyang WANG Jun CHEN Xiaoling National key laboratory of radar signal processing Xidian UniversityXi’an 710071China

Link16 data link is the communication standard of the joint tactical information distribution system(JTIDS)used by the *** and North Atlantic Treaty Organization,which is applied as the opportunistic illuminator for passive radar in this *** time-domain expression of the Link16 signal is established,and its ambiguity function expression is *** timedelay dimension and Doppler dimension side peaks of which lead to the appearance of the false target during target *** solve the problem,the time-delay dimension and Doppler dimension side peaks suppression methods are *** the problem that the conventional mismatched filter(MMF)cannot suppress the time-delay dimension side peaks,a neighborhood MMF(NMMF)is *** results demonstrate the effectiveness of the proposed methods.

关键词： passive radar ambiguity function Link16 mismatched filter(MMF)

Optical sensor array for the discrimination of liquors

在线全文

学校读者我要写书评

暂无评论

未来食品学报(英文) 2024年第1期4卷 48-60页

作者： Yang Yu Fangfang Shi Yi Zhang Fei Li Jinsong Han State key laboratory of Natural Medicines National R&D Center for Chinese Herbal Medicine ProcessingDepartment of Food Quality and SafetyCollege of EngineeringChina Pharmaceutical UniversityNanjing 210009China

The discrimination of liquors plays a vital role in our daily life as a large amount of cheap alcoholic beverages and low-quality counterfeits greatly damage the health of ***-based optical sensors have been developed as a fast and effective tool to discriminate multi-analytes or complex mixtures with similar structures,such as acids,esters,aldehydes and *** the past decades,optical sensor arrays have demonstrated remarkable capabilities in fast and accurate detection of diverse types,qualities,and authentic *** identification strategy mainly focuses on the specific/non-specific interactions of flavor compounds in liquors with sensor *** cross-reactive optical signal readouts from the combination of sensor elements with liquors and multiple machine learning algorithms are essential to ensure the discriminatory capability of sensing *** this review,we discuss the advantages and recent advances in pattern recognition of liquors in terms of the design of various types of sensing materials and the construction strategies of sensor arrays.

关键词： Sensor array Chemical tongue Chemical nose Liquors Fluorescent Colorimetric Pattern recognition Machine learning algorithm

Scale-space effect and scale hybridization in image intelligent recognition of geological discontinuities on rock slopes

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2024年第4期16卷 1315-1336页

作者： Mingyang Wang Enzhi Wang Xiaoli Liu Congcong Wang State key laboratory of Hydro-science and Engineering Tsinghua UniversityBeijing100084China

Geological discontinuity(GD)plays a pivotal role in determining the catastrophic mechanical failure of jointed rock *** and efficient acquisition of GD networks is essential for characterizing and understanding the progressive damage mechanisms of slopes based on monitoring image *** by recent advances in computer vision,deep learning(DL)models have been widely utilized for image-based fracture *** multi-scale characteristics,image resolution and annotation quality of images will cause a scale-space effect(SSE)that makes features indistinguishable from noise,directly affecting the ***,this effect has not received adequate ***,we try to address this gap by collecting slope images at various proportional scales and constructing multi-scale datasets using image processing ***,we quantify the intensity of feature signals using metrics such as peak signal-to-noise ratio(PSNR)and structural similarity(SSIM).Combining these metrics with the scale-space theory,we investigate the influence of the SSE on the differentiation of multi-scale features and the accuracy of *** is found that augmenting the image's detail capacity does not always yield benefits for vision-based recognition *** light of these observations,we propose a scale hybridization approach based on the diffusion mechanism of scale-space *** results show that scale hybridization strengthens the tolerance of multi-scale feature recognition under complex environmental noise interference and significantly enhances the recognition accuracy of *** also facilitates the objective understanding,description and analysis of the rock behavior and stability of slopes from the perspective of image data.

关键词： Image processing Geological discontinuities Deep learning Multi-scale Scale-space theory Scale hybridization

Sensing Matrix Optimization for Random Stepped-Frequency signal Based on Two-Dimensional Ambiguity Function

维普期刊数据库评论

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 Electronics 2024年第1期33卷 161-174页

作者： Mingjiu LYU Hao CHEN Jun YANG Xia WU Ming ZHOU Xiaoyan MA radar NCO School Air Force Early Warning Academy Department of Early Warning Technology Air Force Early Warning Academy

Compressive sensing technique has been widely applied to achieve range-Doppler reconstruction of high frequency radar by utilizing sparse random stepped-frequency(SRSF) signal, which can suppress the complex electromagnetic interference and greatly reduce the coherent processing interval. An important way to improve the performance of sparse signal reconstruction is to optimize the sensing matrix(SM). However, the existing research on the SM optimization needs to design a measurement matrix with superior performance, which needs a large amount of computation and does not consider the influence of the waveform parameters design. In order to improve the superior reconstruction performance, a novel SM optimization approach for SRSF signal is proposed by using two-dimensional ambiguity function(TDAF) in this paper. Firstly, based on the two-dimensional sparse reconstruction model of the SRSFs, the internal relationship between the waveform parameters and the SM was derived. Secondly, the SM optimization problem was directly transformed into the waveform design of SRSFs. Furthermore, on the basis of analyzing the relationship between the mutual coherence matrix of SM and the TDAF matrix of SRSFs, the purpose of optimizing the SM can be achieved by designing the TDAF of the SRSFs. Based on this analysis, a sparse waveform optimization method with joint constraints of maximum and mean sidelobes of the TDAF by using the genetic algorithm was derived. Compared with the traditional SM optimization method, our method not only avoids generating a new measurement matrix, but also further reduces the complexity of the waveform optimization. Simulation experiments verified the effectiveness of the proposed method.

关键词： Correlation Computational modeling Electromagnetic interference Optimization methods signal reconstruction High frequency radar Sensors

Range-angle-dependent beamforming for FDA-MIMO radar using oblique projection

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2022年第5期65卷 223-241页

作者： Lan LAN Guisheng LIAO Jingwei XU Shengqi ZHU Yuhong ZHANG National key laboratory of radar signal processing Xidian University School of Electronic Engineering Xidian University

Frequency diverse array(FDA)-multiple-input and multiple-output(MIMO) radar is characterized with a range-angle-dependent transceive beampattern by introducing incremental frequencies among the transmit array elements and separating the transmitted waveforms with matched filtering in the receiver. In this respect, the paper aims to control the range-angle-dependent transceive beampattern for FDA-MIMO radar by designing the weight vector according to the desired response. At the design stage, the weight vectors to control the beampattern responses of different regions are devised by performing the orthogonal decomposition technique. Then, a filtering matrix using the oblique projection operator is constructed to filter the weight vectors for different regions, where two iterative algorithms are developed either considering concurrent or successive control of multiple regions. In such a way, a desired range-angle-dependent transceive beampattern is formed with simultaneously broadened nulls and a flat-top mainlobe. At the analysis stage,the method has been applied to interference mitigation in FDA-MIMO radar, where the mismatch exists both in the sidelobes and mainlobe. Simulated and measured results are provided to corroborate the effectiveness of the proposed methods.

关键词： FDA-MIMO radar range-angle-dependent beamforming weight vector orthogonal decomposition oblique projection interference mitigation

Seeing at a distance with multicore fibers

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Opto-Electronic Advances 2024年第7期7卷 39-49页

作者： Haogong Feng Xi Chen Runze Zhu Yifeng Xiong Ye Chen Yanqing Lu Fei Xu National laboratory of Solid State Microstructures College of Engineering and Applied Sciencesand Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China College of Physics MIIT Key Laboratory of Aerospace Information Materials and PhysicsState Key Laboratory of Mechanics and Control for Aerospace StructuresNanjing University of Aeronautics and AstronauticsNanjing 211106China

Images and videos provide a wealth of information for people in production and *** most digital information is transmitted via optical fiber,the image acquisition and transmission processes still rely heavily on electronic *** development of all-optical transmission networks and optical computing frameworks has pointed to the direction for the next generation of data transmission and information ***,we propose a high-speed,low-cost,multiplexed parallel and one-piece all-fiber architecture for image acquisition,encoding,and transmission,called the Multicore Fiber Acquisition and Transmission Image System(MFAT).Based on different spatial and modal channels of the multicore fiber,fiber-coupled self-encoding,and digital aperture decoding technology,scenes can be observed directly from up to 1 km *** expansion of capacity provides the possibility of parallel coded transmission of multimodal high-quality *** requires no additional signal transmitting and receiving *** all-fiber processing saves the time traditionally spent on signal conversion and image pre-processing(compression,encoding,and modulation).Additionally,it provides an effective solution for 2D information acquisition and transmission tasks in extreme environments such as high temperatures and electromagnetic interference.

关键词： long-distance fiber imaging image transmission parallel transmission all-optical encoding multicore fiber

Machine learning for parameters diagnosis of spark discharge by electro-acoustic signal

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2024年第8期26卷 64-72页

作者：熊俊卢诗宇刘晓明周文俊查晓明裴学凯 State key laboratory of Power Grid Environmental Protection School of Electrical Engineering and AutomationWuhan UniversityWuhan 430072People’s Republic of China State key laboratory of Reliability and Intelligence of Electrical Equipment Hebei University of TechnologyTianjin 300131People’s Republic of China

Discharge plasma parameter measurement is a key focus in low-temperature plasma *** diagnostics often require costly equipment,whereas electro-acoustic signals provide a rich,non-invasive,and less complex source of discharge *** study harnesses machine learning to decode these *** establishes links between electro-acoustic signals and gas discharge parameters,such as power and distance,thus streamlining the prediction *** building a spark discharge platform to collect electro-acoustic signals and implementing a series of acoustic signal processing techniques,the Mel-Frequency Cepstral Coefficients(MFCCs)of the acoustic signals are extracted to construct the *** machine learning models(Linear Regression,k-Nearest Neighbors,and Random Forest)are introduced and applied to the predictors to achieve real-time rapid diagnostic measurement of typical spark discharge power and discharge *** models display impressive performance in prediction precision and fitting *** them,the k-Nearest Neighbors model shows the best performance on discharge power prediction with the lowest mean square error(MSE=0.00571)and the highest R-squared value(R^(2)=0.93877).The experimental results show that the relationship between the electro-acoustic signal and the gas discharge power and distance can be effectively constructed based on the machine learning algorithm,which provides a new idea and basis for the online monitoring and real-time diagnosis of plasma parameters.

关键词： discharge plasma plasma real-time diagnosis electro-acoustic signal machine learning acoustic signature