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IEEE International Geoscience and Remote Sensing Symposium

作者： Xiangrong Liu Wei Mao Shunsheng Zhang Lei Wu Wen-Qin Wang National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing China Sch. of Info. Comm. Engin. University of Electronic Science and Technology of China Chengdu China

The weighted structure tensor (ST) can be usually used on edge detection of multi-channel images, including polarimetric synthetic aperture radar (polSAR) images. The traditional weighting method is average weighting, each channel considered to provide the same edge information. But in fact different channels tend to contain different amount of edge information, so the traditional weighting method cannot be adopted to extract full edge information of the multi-channel images. This letter proposes a novel weighting method for ST, in which the weight of each channel is obtained by the eigenvalue-measured way. Experimental results show that the proposed method outperforms the traditional method on edge detection.

关键词： Image edge detection Eigenvalues and eigenfunctions Estimation Optical imaging Hyperspectral imaging Corner detection

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Influence of Sea Surface Temperature on the Predictability of Idealized Tropical Cyclone Intensity

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Journal of Tropical Meteorology 2021年第4期27卷 355-367页

作者： ZHONG Quan-jia LI Jian-ping LI Shu-wen WANG Yuan DING Rui-qiang ZHANG Li-feng State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics(LASG) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029 China Multispheres and Earth System(FDOMES)/Key Laboratory of Physical Oceanography/Academy of the Future Oceans Ocean University of ChinaQingdaoShandong 266100 China Laboratory for Ocean Dynamics and Climate Pilot Qingdao National Laboratory for Marine Science and TechnologyQingdaoShandong 266100 China Key Laboratory of Cloud-Precipitation Physics and Severe Storms(LACS) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029 China College of Meteorology and Oceanography National University of Defense TechnologyNanjing 211101 China State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal UniversityBeijing 100875 China

The role of sea surface temperature(SST)forcing in the development and predictability of tropical cyclone(TC)intensity is examined using a large set of idealized numerical experiments in the Weather Research and Forecasting(WRF)*** results indicate that the onset time of rapid intensification of TC gradually decreases,and the peak intensity of TC gradually increases,with the increased magnitude of *** predictability limits of the maximum 10 m wind speed(MWS)and minimum sea level pressure(MSLP)are~72 and~84 hours,*** of the analyses of variance for different simulation time confirm that the MWS and MSLP have strong signal-to-noise ratios(SNR)from 0-72 hours and a marked decrease beyond 72 *** the horizontal and vertical structures of wind speed,noticeable decreases in the magnitude of SNR can be seen as the simulation time increases,similar to that of the SLP or perturbation *** results indicate that the SST as an external forcing signal plays an important role in TC intensity for up to 72 hours,and it is significantly weakened if the simulation time exceeds the predictability limits of TC intensity.

关键词： predictability nonlinear local Lyapunov exponent signal-to-noise ratios tropical cyclone intensity sea surface temperature

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Two-Dimensional Imaging With Stationary Nonuniform Frequency Diverse Array Transmitter

Two-Dimensional Imaging With Stationary Nonuniform Frequency...

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IEEE International Geoscience and Remote Sensing Symposium

作者： Xiangrong Liu Wei Mao Lei Wu National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing China Sch. of Info. Comm. Engin. University of Electronic Science and Technology of China Chengdu China

This paper proposes a simple two-dimensional imaging via stationary nonuniform frequency diverse array (FDA) transmitter by exploiting FDA both range and angle dependent transmit beampattern. The nonuniform FDA transmitter only generates range-dependent beampattern, so that two-dimensional (range-angle dimension) imaging of targets can be achieved without the employment of moving radar platform, by jointly utilizing the only range-dependent transmitter beampattern and general single-antenna or phased-array antenna. The effectiveness of the proposed method is verified by simulation results.

关键词： Radar imaging Imaging Frequency diversity Radar antennas Transmitters Radar remote sensing

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X-band narrowband high-temperature super-conducting filter with high selectivity

X-band narrowband high-temperature super-conducting filter w...

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IET International Radar Conference 2015

作者： L. Gao Z. Y. Jiang J. Q. Liu H. Y. Liu J. L. Bai F. Xu H. Li S. Y. Chen L. Sun Y. B. Bian J. Wang Y. S. He National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics P.O. box 9200 Beijing 100076 China Chinese Academy of Sciences Beijing Beijing CN

ISBN: (纸本)9781510822023

This paper presents a development of a narrowband hightemperature superconducting filter with high selectivity. The center frequency of this filter is 8.625 GHz and the 3 dB bandwidth is 156 MHz (a fractional bandwidth of 1.81 %). In order to achieve high band edge steepness, we introduce a 10-resonator quasi-elliptic function response with two pairs of transmission zeros in the cascaded quadruplet coupling structure. The filter was manufactured on a 2-in-diameter 0.5-mm-thick MgO wafer with double-sided YBCO films. The measured results show a midband insertion loss of 0.58 dB and a return loss better than 16 dB. Band edge steepness reaches over 3.82 dB/MHz at both the high and low frequency edges. The 60 dB rectangle ratio is less than 1.19. The out-of-band rejection is over 60 dB at 17.8 MHz from the 3 dB band edge.

关键词： High-temperature superconducting (HTS) X-band microwave filter transmission zeros

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Design and Simulation of a Planar Printed Slot Array Antenna

Design and Simulation of a Planar Printed Slot Array Antenna

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2023 IEEE International Workshop on Electromagnetics: Applications and Student Innovation Competition, iWEM 2023

作者： Xiaofei, Shi Jiaxin, Shi Jiaqi, Liu Zhongyi, Fang Lei, Wang Lizhong, Song Shandong Institute of Space Electronic Technology Yantai264003 China Harbin Institute of Technology School of Electronics and Information Engineering Harbin150001 China Harbin Institute of Technology at Weihai School of Information Science and Engineering Weihai264209 China Beijing Institute of Space Long March Vehicle National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematics Beijing100076 China Shandong Huayu Aerospace Technology Co. Ltd Yantai264003 China

ISBN: (纸本)9798350336740

This paper designs an array antenna with a planar printed structure. The antenna element adopts a rectangular slot antenna, and the antenna element is excited by a T-shaped feeding structure. The microstrip power distribution network is used to feed the antenna radiator array with equal power. The microstrip power distribution network and slot radiator array are located on top and bottom of dielectric substrate, and the array antenna is implemented by use of the printed circuit technology. In order to improve the gain, a metal reflector ground is placed below the dielectric substrate. A planar printed slot array antenna working in X band is designed. The coaxial line is used to feed the array antenna at the bottom. The whole antenna structure is easy to feed and suitable for fabrication. The designed array antenna was numerically calculated using full wave electromagnetic simulation software. At a working frequency of 10.1GHz, the voltage standing wave ratio (VSWR) of the antenna is about 1.35, and the gain is about 21.46dB. The design of the antenna scheme can be used as a reference for the actual application of engineering. © 2023 IEEE.

关键词： Slot antennas

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Performance test of Fourier transform infrared imaging spectrometer

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Guangxue Jingmi Gongcheng/Optics and Precision Engineering 2015年 23卷 190-196页

作者： Li, Jian-Hua Xue, Feng Xue, Lian Li, Zhi-Feng Liu, Jia-Qi National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematics Beijing100076 China

The paper researches the measurement methods of key parameters of Fourier transform imaging spectrometers. Firstly, the physical meaning of the key parameter Noise Equivalent Spectral Radiance (NESR) was introduced and corresponding calculation model, test principle and data processing method were given. Then, a calibrated black body was used as radiation source, the performance parameters of Fourier transform imaging spectrometer for mid-wavelength and long-wavelength were tested experimentally, including the NESR, radiometric accuracy and spectral errors. test results show that the average NESRs of infrared imaging spectrometer for long-wavelength at 10 μm is 21.4 nW/(cm2·sr·cm-1) and that for mid-wavelength at 4.6 μm is 4.6 nW/(cm2·sr·cm-1). The radiometric accuracies of the spectrometer is less than 0.4 K and 2 K for long-wave and mid-wave, respectively. The spectral errors of the spectrometer for both mid-wavelength and long-wavelength are less than half of the spectral resolution. These parameters are all in the normal range, which verifies the feasibility of test method. It provides references for the periodically measurement of imaging spectrometers. © 2015, Chinese Academy of sciences. All right reserved.

关键词： Temperature measurement

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Isotope-Shift Measurement of Bosonic Yb^(+)Ions

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Chinese physics Letters 2023年第9期40卷 43-47页

作者：乐虹伶邵虎陈正方鹏程曾孟彦张宝林黄垚李冀光陈群峰管桦高克林 State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Innovation Academy of Precision Measurement Science and TechnologyChinese Academy of SciencesWuhan 430071China University of the Chinese Academy of Sciences Beijing 100049China Key Laboratory of Atomic Frequency Standards Innovation Academy of Precision Measurement Science and TechnologyChinese Academy of SciencesWuhan 430071China Institute of Applied Physics and Computational Mathematics Beijing 100088China Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences University of Science and Technology of ChinaHefei 230026China CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of ChinaHefei 230026China Wuhan Institute of Quantum Technology Wuhan 430206China

We present a method that the atomic transition frequency measurement relies on the accurate wavemeter,optical frequency comb and stable Fabry–Pérot cavity to precise determination of stable even isotope shift on single Yb+ion(A=168,170,172,174,176).The 6s^(2)S_(1/2)←→6p^(2)P_(1/2)and 5d^(2)D_(3/2)←→6s^(3)[3/2]_(1/2)resonance dipole transition frequencies are preliminarily measured by using a wavemeter which is calibrated by the 729 nm clock laser of ^(40)Ca^(+).Meanwhile,those frequencies are double checked by using optical frequency comb for correction of ***,by changing frequency locking points at an ultralow expansion cavity more slightly and monitoring the corresponding atomic fluorescence changing with 17%,we finally improve the resonant frequency uncertainty to±6 MHz,which is one order of improvement in precision higher than previously published measurements on the same transitions.A King-plot analysis with sensitivity to coupling between electrons and neutrons is carried out to determine the field and mass shift *** measurement combined with existing or future isotope shift measurements can be used to determine basic properties of atomic nuclei,and to test new forces beyond the Standard Model.

关键词： checked correction resonant

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Topology Optimization of Complex Network based on NSGA-II

Topology Optimization of Complex Network based on NSGA-II

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IEEE Advanced Information technology, Electronic and Automation Control Conference (IAEAC)

作者： Zhang Bin Gan Zhi-chun Chen wen Hu Qiang-qiang Hou Jian-feng Departments of information and communication National University of Defense Technology China Science and Technology on Test Physics & Numerical Mathematic Laboratory China

This paper proposes a complex network topology optimization method based on NSGA-II with degrees and edges number unchanged. The method selects the elite parent networks by applying non-dominated layer sorting and congestion degree calculation through the network crossover and mutation operation to achieve maximum network efficiency and network invulnerability. Simulation analysis shows that the method can significantly improve the invulnerability and network efficiency of the initial networks at the same time. Optimizing the network efficiency makes the network connection show a negative correlation. The network presents a "multi-core decentralized" structure; optimizing the network invulnerability makes the connection show a positive correlation, the network presents a "close core and scattered periphery" structure; the cooperative optimization makes the network present a "tighter core and large periphery" structure, which is proved with good theoretical generality and practical application value.

关键词： Optimization Sociology Complex networks Correlation Topology

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An Improved DSDV Protocol based on Link Stability with Adaptive Period for Intra-cluster Routing in High-dynamic Flying UAV Networks

An Improved DSDV Protocol based on Link Stability with Adapt...

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International Applied Computational Electromagnetics Society Symposium (ACES)

作者： Yiguo Zhang Lai Qian Xiaoqin Xue Wei Wang College of Computer Science Xi’an Polytechnic University Xi’an China National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing Institute of Space Long March Vehicle Beijing China

We propose a stability-based adaptive-period DSDV intra-cluster routing protocol that automatically adjusts the routing update period by the link stability among the nodes in the cluster structure, thus reducing the network overhead of the network structure in maintaining the routing table. We describe the link stability and adaptive period implementation and test the proposed routing protocol in the cluster structure based on network simulation. The implementation results show that the proposed routing protocol has better performance than the traditional DSDV routing protocol, can improve the network throughput and reduce the routing overhead in the network, and has good adaptability in the cluster with fast changing network topology.

关键词： Costs Adaptive systems Network topology Routing Throughput Computational electromagnetics Routing protocols

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Statistical analysis and simulation method of forward scattering clutter in bistatic radar

Statistical analysis and simulation method of forward scatte...

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IET International Radar Conference 2013

作者： Zhang, Chuan-Fang Liu, Chang-Jiang Hu, Cheng Liu, Xiang-Rong Beijing Institute of Technology School of Information and Electronics Beijing 100081 China National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematical Beijing China

ISBN: (纸本)9781849196031

The research of statistical properties and simulation methods of radar clutter have vital importance to the design, simulation and development of radar systems. Based on the analysis of some experimental data of forward scattering radar (FSR) clutter, it was found that under low wind speed and narrow dynamic range, the amplitude of FSR clutter was subject to K distribution;while under high wind speed or wide dynamic range, it was subject to lognormal distribution;the clutter power spectrum was subject to the fourth-order all-pole model. With the above statistical analysis, the forward scatter coherent clutter was simulated using a method combining zero-memory nonlinear transformation with spherically invariant random process. The statistical characteristics of the simulated clutter were identical to those of the measured clutter, which verified the validity of this method.

关键词： Radar clutter

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