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Influence factors of sparse microwave imaging radar system performance:approaches to waveform design and platform motion analysis

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Science china(Information sciences) 2012年第10期55卷 2301-2317页

作者： zhang Zhe 1,2.3,zhang BingChen 1,2.JIANG ChengLong 1,2.3,XIANG Yin 1,2.HONG Wen 1,2.& {2. YiRong 1,2.1 Science and Technology on Microwave Imaging Laboratory,{2.,china 2.institute of Electronics,chinese academy of sciences,{2.,china 3 Graduate University,chinese academy of sciences,{2.,china Science and Technology on Microwave Imaging Laboratory Beijing China institute of Electronics Chinese Academy of Sciences Beijing China Graduate University Chinese Academy of Sciences Beijing China

Sparse microwave imaging radar is a newly developed concept of microwave imaging system,which tries to combine the traditional radar imaging system with sparse signal processing theories,achieving the aim of reducing the complexity of microwave imaging systems and enhancing the system *** this paper,we introduce some basic concepts of sparse signal processing theory,and then apply it to the traditional radar imaging system to get the mathematical model of sparse microwave imaging *** analyze the factors that determine the performance of sparse microwave imaging radar,including scene,waveform and *** to the radar model,we analyze how these factors influence the radar system and how to optimize *** results of the sparse microwave imaging radar system are also provided.

关键词： sparse microwave imaging radar synthetic aperture radar compressive sensing Lq regularization waveform design

Comparative study of pollination biology of two closely related alpine Primula species,namely Primula beesiana and *** (Primulaceae)

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Journal of Systematics and Evolution 2010年第2期48卷 109-117页

作者： 1,2.hi-Kun wu 1Chang-Qin zhang 1(Kunming {2. of Botany,{2.,Kunming 6502.4,china) 2.Graduate School of {2.,beijing 100049,china) (Kunming institute of Botany Chinese Academy of Sciences Kunming 650204 China) (Graduate School of chinese academy of sciences Beijing 100049 China)

The comparative pollination biology of a population of Primula beesiana,a population of ***,and an overlapping population of these two species in Yulong Shan,Yunnan Province,china,was studied in 2.04 and *** results indicate that both *** and *** are typical heterostylous and obligate outcrossing species;the main pollinators of the two species were bees and *** the sites of all three populations,the main pollinating visitors of the two species showed preference for one of the two species,resulting in the ethological isolation of the two species by the *** ethological isolation contributes to the reproductive isolation of the two species,which supports the hypothesis that *** and *** are two distinct *** reproductive isolation of the two species (ethological isolation) is probably an important mechanism in maintaining species boundaries in the genus and has contributed to the species diversification of Primula in the *** addition,gene exchanges between *** and *** has occurred to some extent in the overlapping population,but whether natural hybridization has contributed to species diversification in Primula remains to be determined.

关键词： pollination biology Primula beesiana Primula bulleyana reproductive isolation

Some key technics of drop tower experiment device of National Microgravity Laboratory (china) (NMLC)

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Science china(Technological sciences) 2005年第3期48卷 305-316页

作者： zhang Xiaoqian 1 , YUAN Longgen 1 , wu Wendong 1 , TIAN Lanqiao 2.& YAO Kangzhuang 2.1. {2. of Engineering Thermophysics, {2., beijing 100080, china 2. {2. of Mechanics, {2., beijing 100080, china institute of Engineering Thermophysics Chinese Academy of Sciences Beijing China institute of Mechanics Chinese Academy of Sciences Beijing China

Drop tower is an important ground based facility for microgravity science experiment. The technical performances of the drop tower NMLC are advanced compared with similar facilities in the US, Germany and Japan. The main components such as drop capsule, deceleration devices, release mechanism present its advantages and creativities.

关键词： drop tower facility,drop capsule,deceleration devices,release mechanism.

维普期刊数据库

LOL: a highly flexible framework for designing stream ciphers

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Science china(Information sciences) 2024年第9期67卷 62-75页

作者： Dengguo FENG Lin JIAO Yonglin HAO Qunxiong ZHENG wenling wu Wenfeng QI Lei {2. {2. {2. Siwei SUN Tian TIAN State Key Laboratory of Cryptology PLA Strategic Support Force Information Engineering University institute of software Chinese Academy of Sciences Westone Cryptologic Research Center School of Cryptology University of Chinese Academy of Sciences

In this paper, we propose LOL, a general framework for designing blockwise stream ciphers. The proposed framework achieves ultrafast software implementations for ubiquitous virtual networks in 5G/6G environments and high-security levels for post-quantum cryptography. The LOL framework is structurally strong; furthermore, this framework and all its components enjoy high flexibility with various extensions. On the basis of the LOL framework, we propose new stream-cipher designs called LOL-MINI and LOL-DOUBLE with the support of the AES-NI and single instruction multiple data instructions. The former applies the basic LOL single mode, while the latter uses the extended parallel-dual mode. LOL-MINI and LOL-DOUBLE support 2.6-bit key length. Our thorough evaluations revealed that these cipher designs have 2.6-bit security margins against all existing cryptanalysis methods, including differential, linear, and integral. The software performances of LOL-MINI and LOL-DOUBLE can reach 89 and 135 Gbps. In addition to pure encryptions,the LOL-MINI and LOL-DOUBLE stream ciphers can be applied in a stream-cipher-then-MAC strategy to make AEAD schemes.

关键词： stream cipher 5G/6G mobile system fast software implementation

Sparse microwave imaging:Principles and applications

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Science china(Information sciences) 2012年第8期55卷 1722-1754页

作者： zhang BingChen1,2.HONG Wen1,2.& wu YiRong1,2.1Science and Technology on Microwave Imaging Laboratory,{2.,{2. 2.4} of Electronics,chinese academy of sciences,{2.,{2. Science and Technology on Microwave Imaging Laboratory Beijing China institute of Electronics Chinese Academy of Sciences Beijing China

This paper provides principles and applications of the sparse microwave imaging theory and *** aperture radar(SAR) is an important method of modern remote *** decades microwave imaging technology has achieved remarkable progress in the system performance of microwave imaging technology,and at the same time encountered increasing complexity in system *** sparse microwave imaging introduces the sparse signal processing theory to radar imaging to obtain new theory,new system and new methodology of microwave *** on classical SAR imaging model and fundamental theories of sparse signal processing,we can derive the model of sparse microwave imaging,which is a sparse measurement and recovery problem and can be solved with various *** exist several fundamental points that must be considered in the efforts of applying sparse signal processing to radar imaging,including sparse representation,measurement matrix construction,unambiguity reconstruction and performance *** on these considerations,the sparse signal processing could be successfully applied to radar imaging,and achieve benefits in several aspects,including improvement of image quality,reduction of data amount for sparse scene and enhancement of system *** sparse signal processing has also been applied in several specific radar imaging applications.

关键词： sparse microwave imaging sparse signal processing compressive sensing synthetic aperture radar radar imaging

Multi-channel SAR imaging based on distributed compressive sensing

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Science china(Information sciences) 2012年第2期55卷 245-259页

作者： LIN YueGuan1,2.3,zhang BingChen1,2.JIANG Hai1,2.3,HONG Wen1,2.& wu YiRong1,2.1National Key Laboratory of Science and Technology on Microwave Imaging,{2.,{2. 2.4} of Electronics,chinese academy of sciences,{2.,{2. 3Graduate University of chinese academy of sciences,beijing 100049,{2. National Key Laboratory of Science and Technology on Microwave Imaging Beijing China institute of Electronics Chinese Academy of Sciences Beijing China Graduate University of chinese academy of sciences Beijing China

The rapid development of compressive sensing(CS)shows that it is possible to recover a sparse signal from very limited *** aperture radar(SAR)imaging based on CS can reconstruct the target scene with a reduced number of collected samples by solving an optimization *** multi-channel SAR imaging based on CS,each channel requires sufficient samples for separate imaging and the total number of samples could still be *** propose an imaging algorithm based on distributed compressive sensing(DCS)that reconstructs scenes jointly under multiple ***-channel SAR imaging based on DCS not only exploits the sparsity of the target scene,but also exploits the correlation among *** requires significantly fewer samples than multi-channel SAR imaging based on *** multiple channels offer different sampling rates,DCS joint processing can reconstruct target scenes with a much more flexible allocation of the number of measurements offered by each channel than that used in separate CS processing.

关键词： synthetic aperture radar multi-channel synthetic aperture radar compressive sensing distributed compressive sensing

Enhanced visible-light photocatalytic hydrogen evolution using two-dimensional carbon nitride sheets with the removal of amine groups

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chinese Chemical Letters 2024年第2期35卷 446-450页

作者： Yu zhang liting {2. Shaopeng Wang Dingyi Yang Huan Liang Yizhang {2. Jian Hao Youqing Wang Jianke Liu Yong Wang Department of Physics Shaanxi University of Science and TechnologyXi'an 710021China School of Advanced Materials and Nanotechnology Academy of Advanced Interdisciplinary ResearchXidian UniversityXi'an 710126China The State Key Discipline Laboratory of Wide Band Gap Semiconductor Technology Xidian UniversityXi'an 710126China Collaborative Innovation Center of Advanced Microstructures National Laboratory of Solid State MicrostructuresNanjing UniversityNanjing 210093China State Key Laboratory of High-Efficiency Utilization of Coal and Green Chemical Engineering Ningxia UniversityYinchuan 750021China

Two-dimensional(2.)carbon nitride sheets(CNs)with atomically thin structures are regarded as one of the most promising materials for solar energy ***,due to their substantially enlarged bandgap caused by the strong quantum size effect and their incomplete polymerisation with a large number of non-condensed surface amino groups,the practical applicability of CNs in photocatalysis is *** this study,CNs with broad visible-light absorption were synthesised using a 5-min fast thermal *** removal of uncondensed amine groups reduces the bandgap of CNs from 3.06 eV to 2.60 eV,increasing their absorption of visible ***,the CNs were distorted after annealing,which can differentiate the spatial positions of electrons and holes,enhancing the visible-light absorption *** a result,when exposed to visible light,the photocatalytic hydrogen production activity of atomically thin 2. CNs rose by 8.38 *** research presents a dependable and speedy method for creating highly effective visible-light photocatalysts with narrowed bandgaps and improved visible-light absorption.

关键词： 2. carbon nitride sheets Rapid thermal annealing DFT calculations Visible-light absorption visible-light photocatalysis

维普期刊数据库

Formation of super-concentrated hydrochloric acid in the third phase in tertiary amine N2.5-PtCl_6^(2.)-HCl system and its influences on the Pt microemulsion extraction

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Science china Chemistry 2009年第11期52卷 1825-1834页

作者： HUANG Kun1,CHEN Jing1,zhang ChengFeng1,2.LI ZhiHong3,PAN QingHua1,SUN Yan1,LIU ShaoXuan1,LIU XueXin2.LI WeiHong1,YANG ZhanLan1,WENG ShiFu1,HU TianDou3,XU YiZhuang1 & wu JinGuang1 1 College of Chemistry and Molecular Engineering,Peking University,{2. 100871,{2. 2.institute of Chemistry,chinese academy of sciences,beijing 100190,{2. 3 institute of High Energy Physics,chinese academy of sciences,{2. 100049,{2. College of Chemistry and Molecular Engineering Peking University Beijing China institute of Chemistry Chinese Academy of Sciences Beijing China institute of High Energy Physics Chinese Academy of Sciences Beijing China

In this paper,we have investigated the formation of the third-phase in tertiary amine(N2.5)-PtCl62.-HCl system and the microscopic phase structural evolution of platinum-loaded organic phases before and after the occurrence of the *** third-phase is characterized by various spectroscopic techniques,and the small angle X-ray scattering(SAXS) experiments demonstrate the appearance of nano-aggregates,i.e.,water-in-oil reversed micelles,in the third *** experimental results indicate that(1) formation of the third phase is related to the aggregation behaviors of nano-reversed micelles in which a super-concentrated hydrochloric acid formed with the H+ to H2. molar ratio being much higher than that of the conventional 37 wt% saturated hydrochloric acid.(2. The occurrence of the super-concentrated HCl results in a great amount of H+ and Cl-ions enriched and confined within the nano-water pools of W/O reversed micelles in third ***,the coordination behaviors of platinum complex ions in that super-concentrated hydrochloric acid are very different from their corresponding behaviors in bulk aqueous *** is possible that H+ ions participate in the formation of such complexes as HmPtCl6z+ in the super-concentrated hydrochloric acid.(3) The relative contents of various HmPtCl6z+ complexes are different corresponding to the H+ ion concentrations in confined nanowater *** association ability of the acidified tertiary amine N2.5 molecules(R3NH+) with various HmPtCl6z+ complexes plays an important role in affecting the platinum extraction behaviors.

关键词： solvent extraction third phase super-concentrated hydrochloric acid tertiary amine platinum

维普期刊数据库

A Residual Frequency Offset Estimation Method Based on Range Migration Fitting

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Journal of beijing institute of Technology 2024年第2期33卷 103-110页

作者： liting zhang Hao Huan Ran Tao Xiaogang Tang School of Information and Electronics Beijing Institute of Technology School of Aerospace Information Space Engineering University

Recently, researchers have proposed an emitter localization method based on passive synthetic aperture. However, the unknown residual frequency offset(RFO) between the transmitter and the receiver causes the received Doppler signal to shift, which affects the localization accuracy. To solve this issue, this paper proposes a RFO estimation method based on range migration fitting. Due to the high frequency modulation slope of the linear frequency modulation(LFM)-modulation radar signal, it is not affected by RFO in range compression. Therefore, the azimuth time can be estimated by fitting the peak value position of the pulse compression in range ***, the matched filters are designed under different RFOs. When the zero-Doppler time obtained by the matched filters is consistent with the estimated azimuth time, the given RFO is the real RFO between the transceivers. The simulation results show that the estimation error of azimuth distance does not exceed 2. m when the received signal duration is not less than 3 s, the pulse repetition frequency(PRF) of the transmitter radar signal is not less than 1 k Hz, the range detection is not larger than 1 000 km, and the signal noise ratio(SNR) is not less than –5 d B.

关键词： range migration fitting (RMF) passive localization residual frequency offset (RFO)