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IET International Radar Conference (IET IRC 2020)

作者： Y. Chen Y. Wang Q. Tang H. Zhou Science and Technology on Near-Surface Detection Laboratory China School of Electronic and Optical Engineering Nanjing University of Science and Technology Nanjing China Shanghai Spaceflight Electronic and Communication Equipment Research Institute China

The theory of Characteristic Modes can better express the physical concept of radiator. In this paper, a fast method for synthesizing the radiation pattern of an unmanned aerial vehicle (UAV) platform is presented based on the characteristic mode theory. We can synthesize specific radiation patterns of the target to reduce or increase radiation energy in specific directions.

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Structure patterns of one-step synthesis of CuNi nanopowders in air environment: Experiment and atomistic simulations

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Nano-Structures and Nano-Objects 2024年 40卷

作者： Romanovski, Valentin Sdobnyakov, Nickolay Kolosov, Andrey Savina, Kseniya Nepsha, Nikita Moskovskikh, Dmitry Dobryden, Illia Zhang, Zhaowei Beletskii, Evgenii Romanovskaia, Elena Department of Materials Science and Engineering University of Virginia Charlottesville 22904 VA United States Department of General Physics Tver State University Tver 170002 Russian Federation Science and Research Centre of Functional Nano-Ceramics National University of Science and Technology “MISIS” Lenin av. 4 Moscow 119049 Russian Federation KTH Royal Institute of Technology Department of Chemistry Division of Surface and Corrosion Science Drottning Kristinas väg 51 Stockholm SE-100 44 Sweden Oil Crops Research Institute of Chinese Academy of Agricultural Sciences Wuhan 430062 China Key Laboratory of Biology and Genetic Improvement of Oil Crops Key Laboratory of Detection for Mycotoxins National Reference Laboratory for Agricultural Testing Wuhan 430062 China Hubei Hongshan Laboratory Wuhan 430000 China Institute of Chemistry St. Petersburg University Universitetskaya Emb.7/9 St. Petersburg 199034 Russian Federation

A possibility for one-step synthesis of bimetallic CuNi nanopowders in a different ratio of Ni to Cu by solution combustion synthesis technique under normal air atmosphere without any post reduction is reported. The effect of different types of fuels like citric acid and glycine on the combustion process and characteristics of resultant solid products were investigated. XRD results showed the existing of CuNi as a main phase and small amounts of CuO and (Ni,Cu)₄N. Determined CuNi particle sizes were in the range of up to 50 nm. Computer simulation was performed using the molecular dynamics method for similar concentration compositions, but in size range of 4.5–5.5 nm, as a result of cooling the system from 1700 K to 300 K. In addition, two types of melting scenario of binary CuNi NPs were studied: 1) heterogeneous melting of monocrystalline Cu and Ni NPs;2) melting of the crystallization products of binary NPs. Melting temperatures weakly depend on the choice of the above-mentioned melting scenario. However, the nature of subsequent crystallization can be influenced by the initial energy of the system, which is higher for case 1. The characteristic temperatures of phase transitions of melting and crystallization are determined based on the analysis of hysteresis loops of the specific potential part of the internal energy of NPs. The patterns of atomic and structural segregation in binary CuNi NPs were studied. © 2024 Elsevier B.V.

关键词： CuNi nanoparticles Homogeneous composites Molecular dynamics simulation Segregation Solution combustion synthesis

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Improved Capon Beamformer Using Fourier Integral Method (FIM)

Improved Capon Beamformer Using Fourier Integral Method (FIM...

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OCEANS

作者： Xionghou LIU Cong Wang Chao Sun Yixin Yang Jie Zhuo Guoqing Jiang Wenjun Duan Science and Technology on Near-Surface Detection Laboratory Wu Xi P. R. China School of Marine Science and Technology Northwestern Polytechnical University Xi'an P. R. China

ISBN: (数字)9781728154466

ISBN: (纸本)9781728184098

When compared to the conventional beamformer (CBF), the Capon beamformer often shows a better target detection performance. However, when the array aperture (or, the degrees of freedoms-DOFs) is limited and the signal-to-noise ratio (SNR) is relatively low, the performance of the Capon beamformer will degrade severely. Unfortunately, for the practical application the target of interest is often submerged in loud interferences and high-level fluctuated noises. Thus, it is very hard for a small-aperture array to find the target of interest. In this paper, to improve the beamforming performance of the small-aperture linear array, we propose an improved Capon beamformer based on Fourier integral method (FIM), which is termed as FIM-Capon for short. FIM-Capon firstly uses the basic theory of FIM to obtain 2N-1 outputs (the number of hydrophones in the array is N), which is actually the Toeplitz averaged covariance matrix calculated from the sampled array covariance matrix. And then, FIM-Capon uses the subarray smoothing and the Capon beamformer to process the 2N-1 outputs of the Toeplitz averaged covariance matrix to produce the final beamforming output. The proposed FIM-Capon method have two advantages; one is making use of the noise suppression ability of FIM, and the other is using the extended DOFs coming from the Toeplitz averaging. Hence, FIM-Capon has a higher input SNR and a larger DOF than the traditional Capon beamformer. As a result, when the aperture is limited and the input SNR is low, FIM-Capon shows a better weak target detection performance than the traditional Capon beamformer. Numerical simulations validate the effectiveness of the proposed FIM-Capon method.

关键词： Smoothing methods Array signal processing Sonar equipment Object detection Apertures Covariance matrices Signal to noise ratio

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A Co-offset GPR Data Inversion Based on Ray Theory

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IOP Conference Series: Earth and Environmental science 2021年第1期660卷

作者： Meiqi Xue Sixin Liu Qi Lu Hongqing Li Yuanxin Wang School of Earth Exploration Science and Technology Jilin University Changchun China Science and Technology on Near-Surface Detection Laboratory Wuxi

We use Monte Carlo method to establish a randomly undulating homogeneous layered medium model. Then the co-offset GPR data for the built geological model is simulated by FDTD. The ray-tracing based inversion is applied for interval velocity estimation. During the inversion, the offset between antennas, the velocity value of the first layer, the picked amplitudes values of each reflection layer and reference amplitude are the input data. The thickness and velocity of each layer are calculated by this recursive method. It is proved that this inversion method is feasible for the layered geological model with random undulation, and the fact that undulation, i.e. RMS height and correlation length, influences the inversion results is discussed.

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On Range-dimensional Performance Improvement of FD-MIMO Sonar Using Deconvolution

On Range-dimensional Performance Improvement of FD-MIMO Sona...

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OCEANS

作者： Jingrong WU Xionghou Liu Chao Sun Guangyu Jiang Dezhi Kong Kuan Fan School of Marine Science and Technology Northwestern Polytechnical University Xi'an P. R. China Science and Technology on Near-Surface Detection Laboratory Wu Xi P. R. China

ISBN: (数字)9781728154466

ISBN: (纸本)9781728184098

The frequency diverse multiple-input multiple-output (FD-MIMO) sonar can achieve improved detection performance in the range dimension by synthesizing echoes at different frequency bands without over-demanding system bandwidth. However, the existing bandwidth synthesis (BS) method suffers from high-level range sidelobes caused by the spectral leakage of the subband signals and the discontinuity of the synthesized spectrum. Hence, it is hard to detect a weak target in the range dimension. To address this problem, a deconvolved bandwidth synthesis (DBS) method is proposed, which can suppress the range-dimensional sidelobes by post-processing the beam output of the synthesized spectrum. To be specific, we first employ the narrowband frequency diverse linear frequency modulated (FD-LFM) pulses to construct the range-dimensional point spread function (PSF), and then apply the PSF and the Richardson-Lucy (R-L) algorithm to deconvolve the data obtained by synthesizing spectra of the subband signals. Simulation results indicate that for the FD-MIMO sonar the proposed DBS method shows a better interference rejection ability and a higher range resolution in the range dimension than the BS method.

关键词： Sonar Satellite broadcasting Signal to noise ratio Frequency diversity Frequency modulation Deconvolution Array signal processing

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A Study on the Relationship Between the detection Distance of Borehole Radar and the Resistivity of Background Medium

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IOP Conference Series: Earth and Environmental science 2021年第1期660卷

作者： Weicun Yan Sixin Liu College of Geo-exploration Science and Technology Jilin University Changchun China Science and Technology on Near-Surface Detection Laboratory Wuxi China

Borehole radar has been widely used in engineering, exploration and other fields, and the detection distance of borehole radar is an important indicator to measure its performance. The detection distance of borehole radar is affected by many factors, including the radar system, the physical properties of background medium, the borehole environment and so on. In this paper, the relationship between the detection distance of the borehole radar and the resistivity of background medium is studied by numerical simulation. The experimental results show that the detection distance of borehole radar increases with the increase of the resistivity of background medium, and the relationship between them is approximately linear. This kind of simulation is helpful to the theoretical study of the borehole radar.

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Research on radio imaging method (RIM) multifrequency information fusion methods

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IOP Conference Series: Earth and Environmental science 2021年第1期660卷

作者： Jianfu Ni Xue Han Sixin Liu College of Geo-Exploration Science and Technology Jilin University Changchun China Science and Technology on Near-Surface Detection Laboratory Wuxi China

Radio imaging method (RIM) also called cross-hole electromagnetic wave method, is widely used in mineral exploration, engineering exploration and other fields. The RIM system can collect multi-frequency information, but the use of multi-frequency information is still limited to qualitative analysis or only one type of frequency information is used. By summarizing the multi-frequency information utilization methods appearing in a variety of geophysical methods, and the feasibility of RIM multi-frequency utilization is proved through theoretical analysis, three multi-frequency information fusion methods suitable for RIM are proposed, namely multi-frequency inversion strategies, Multi-frequency data fusion and multi-frequency image fusion. An example application analysis shows that the three multi-frequency information fusion methods make full use of the advantages of different frequencies and can improve the imaging result.

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Search for the lepton favor violating decay J/ψ→eμ

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science China(Physics,Mechanics & Astronomy) 2023年第2期66卷 24-33页

作者： BESII Collaboratio Institute of High Energy Physics Beijing 100049 China Beihang University Beijing 100191 China Beijing Institute of Petrochemical Technology Beijing 102617 China Bochum Ruhr-University Bochum D-44780 Germany Carnegie Mellon University Pittsburgh 15213 USA Central China Normal University Wuhan 430079 China Central South University Changsha 410083 China China Center of Advanced Science and Technology Beijing 100190 China COMSATS University Islamabad Lahore Campus Defence Road Off Raiwind Road Lahore 54000 Pakistan Fudan University Shanghai 200433 China G.I. Budker Institute of Nuclear Physics SB RAS (BINP) Novosibirsk 630090 Russia GSI Helmholtzcentre for Heavy Ion Research GmbH Darmstadt D-64291 Germany Guangxi Normal University Guilin 541004 China Guangxi University Nanning 530004 China Hangzhou Normal University Hangzhou 310036 China Hebei University Baoding 071002 China Helmholtz Institute Mainz Staudinger Weg 18 Mainz D-55099 Germany Henan Normal University Xinxiang 453007 China Henan University of Science and Technology Luoyang 471003 China Henan University of Technology Zhengzhou 450001 China Huangshan College Huangshan 245000 China Hunan Normal University Changsha 410081 China Hunan University Changsha 410082 China Indian Institute of Technology Madras Chennai 600036 India Indiana University Bloomington 47405 USA INFN Laboratori Nazionali di Frascati INFN Laboratori Nazionali di Frascati Frascati I-00044 Italy INFN Laboratori Nazionali di Frascati INFN Sezione di Perugia Perugia I-06100 Italy INFN Laboratori Nazionali di Frascati University of Perugia Perugia I-06100 Italy INFN Sezione di Ferrara INFN Sezione di Ferrara Ferrara I-44122 Italy INFN Sezione di Ferrara University of Ferrara Ferrara I-44122 Italy Institute of Modern Physics Lanzhou 730000 China Institute of Physics and Technology Peace Avenue 54B Ulaanbaatar 13330 Mongolia Jilin University Changchun 130012 China Johannes Gutenberg Univers

We present a search for the lepton flavor violating decay J/ψ→e±μ?using 8.998×109J/ψevents collected with the BESⅢdetector at the BEPCⅡe+e-storage *** excess of signal above background is observed;we therefore set an upper limit on the branching fraction of B(J/ψ→e±μ?)<4.5×10-9at the 90%confidence *** the previous best result by a factor of more than 30,this measurement places the most stringent limit to date on lepton flavor violation in the heavy quarkonium sector.

关键词： BESⅢ decay limit

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Research on Intelligent Acoustic Positioning System Based on Kalman Filter Model

Research on Intelligent Acoustic Positioning System Based on...

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2018 Chinese Automation Congress, CAC 2018

作者： Ming, Zhao Kai, Ding Yingjiao, Rong Hanming, Qian Science and Technology on Near-Surface Detection Laboratory WUXI China

ISBN: (纸本)9781728113128

Passive acoustic positioning is the use of acoustic sensor array to receive target acoustic signals, Extracting spatial information of the sound source through signal processing, a positioning technique to determine the target orientation and distance. In this paper, the Kalman filter algorithm is used to estimate the delay of different sensor signals, and the spatial azimuth geometry algorithm is used to analyze the target azimuth and elevation angle. A control method is designed to keep the S curve of the motor smooth and simplify the S-curve acceleration and deceleration. The azimuth angle is controlled by the new S-curve to control the horizontal motor, which can effectively monitor the target.1 © 2018 IEEE.

关键词： Kalman filters

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Research on Propagation Characteristics of Seismic Signal for Moving Armoured Targets

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IOP Conference Series: Earth and Environmental science 2021年第1期660卷

作者： Kai Ding Shoujun Zheng Xinghua Li Yingjiao Rong Science and Technology on Near–Surface Detection Laboratory Wuxi China 214035 Army Engineering University of PLA Nanjing China 210007

This paper is focused on the Seismic Signal characteristics of wheel and track vehicles. The effect of vehicle speed of these two vehicles on the Seismic Signal was studied through experimental and theorical methods. The Seismic Signal s of these two vehicles with two different speeds were tested firstly. Then the measured signals were analyzed by means of the power spectrum method and the wavelet transform method, respectively. And the time- and frequency domain features of the signals were obtained subsequently. Finally, the influence of the speed and type of vehicle on the time- and frequency domain features of the signal and its propagation characteristic were investigated. The results show that, with the propagation of vehicle speed and distance, there is a similar varying law of the Seismic Signal for different vehicles. However, the difference of the time- and frequency domain feature between the two vehicles are striking.

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