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Cognitive anti-jamming receiver under phase noise in high frequency bands

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Journal of Systems Engineering and Electronics 2018年第1期29卷 31-38页

作者： fang zheng LI Haitao QIAN Yiming School of Electronic Information and Electrical EngineeringShanghai Jiao Tong UniversityShanghai 200240China China Science and Technology on Avionics Integration Laboratory Shanghai 200233China Faculty of Information Technology Beijing University of TechnologyBeijing 100124China China Nuclear Control System Engineering CO. LTDBeijing 100176China

This paper investigates the jamming sensing performance of the simultaneous transmit and receive based cognitive anti-jamming(SCAJ) receiver impaired by phase noise in local oscillators(LO) over fading channels. Firstly, energy detection(ED)based on the jamming to noise ratio(JNR) of the high frequency bands SCAJ receiver with phase noise under different channels is analyzed. Then, the probabilities of jamming detection and false alarm in closed-form for the SCAJ receiver are derived. Finally,the modified Bayesian Cramer-Rao bound(BCRB) of jamming sensing for the SCAJ receiver is presented. Simulation results show that the performance degradation of the SCAJ system due to phase noise is more severe than that due to the channel fading in the circumstances where the signal bandwidth(BW) is kept a constant. Moreover, the signal BW has an effect on the phase noise in LO, and the jamming detection probability of the wideband SCAJ receiver with lower phase noise outperforms that of the narrowband receiver using the same center frequency. Furthermore,an accurate phase noise estimation and compensation scheme can improve the jamming detection capability of the SCAJ receiver in high frequency bands and approach to the upper bound.

关键词： high frequency band simultaneous transmit and receive phase noise cognitive anti-jamming

Start-up current adaptive control for sensorless high-speed brushless DC motors based on inverse system method and internal mode controller

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Chinese Journal of Aeronautics 2017年第1期30卷 358-367页

作者： He Yanzhao zheng Shiqiang fang Jiancheng School of Instrumentation Science and Opto-electronics Engineering Beihang University Beijing 100083 China Beijing Engineering Research Center of High-Speed Magnetically Suspended Motor Technology and Application Beijing 100083 China

The start-up current control of the high-speed brushless DC（HS-BLDC） motor is a challenging research topic. To effectively control the start-up current of the sensorless HS-BLDC motor, an adaptive control method is proposed based on the adaptive neural network（ANN）inverse system and the two degrees of freedom（2-DOF） internal model controller（IMC）. The HS-BLDC motor is identified by the online least squares support vector machine（OLS-SVM） algorithm to regulate the ANN inverse controller parameters in real time. A pseudo linear system is developed by introducing the constructed real-time inverse system into the original HS-BLDC motor system. Based on the characteristics of the pseudo linear system, an extra closed-loop feedback control strategy based on the 2-DOF IMC is proposed to improve the transient response performance and enhance the stability of the control system. The simulation and experimental results show that the proposed control method is effective and perfect start-up current tracking performance is achieved.

关键词： Adaptive control Brushless DC motors Inverse systems Internal model controller Neural networks Start-up Support vector machines

A Study of Animated Transition in Similarity-Based Tiled Image Layout

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Tsinghua Science and Technology 2013年第2期18卷 157-170页

作者： huan Zhang Jun Tao fang Ruan Chaoli Wang Dematic Corp Grand Rapids MI 49505USA the Department of Computer Science Michigan Technological University Houghton MI49931 USA Google Inc Mountain View CA 94043USA

For many information visualization applications, showing the transition when interacting with the data is critically important as it can help users better perceive the changes and understand the underlying data. In this paper, we investigate the effectiveness of animated transition in a tiled image layout where the spiral arrangement of the images is based on their similarity. Three aspects of animated transition are considered, including animation steps, animation actions, and flying paths. Exploring and weighting the advantages and disadvantages of different methods for each aspect and in conjunction with the characteristics of the spiral image layout, we present an integrated solution, called AniMap, for animating the transition from an old layout to a new layout when a different image is selected as the query image. We show the effectiveness of our animated transition solution by demonstrating experimental results and conducting a comparative user study.

关键词： animated transition image layout large image collections user study

A New Information Method to Determinate Corrosion Types from Electrochemical Noise

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Acta Metallurgica Sinica(English Letters) 2015年第4期28卷 449-453页

作者： Jian Li huan-Jun zheng Ye zheng Wei-Kang Kong Ke Wang State Key Laboratory of Precision Measuring Technology and Instrument Tianjin University School of Materials Science and Engineering Tianjin University

Electrochemical noise data in the presence of different corrosion types were analyzed. A correlation between the corrosion type of the observed noise and the entropy rate was recognized. A sequence was transformed from each set of original electrochemical noise signal, then the Markov process M and stationary distribution μ were calculated. Finally, entropy rate of each sequence was obtained by the definition. From the entropy rate, it has been observed that local corrosion showed a lower entropy rate, while uniform corrosion showed a higher entropy rate.

关键词： Entropy rate Stainless steel Corrosion Electrochemical behavior

Evolution of the Mid-tropospheric Vortex during the Formation of Super Typhoon Megi(2010)

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Advances in Atmospheric Sciences 2020年第7期37卷 751-765页

作者： Li ZHUO Dexian fang zheng WU Juan fang Key Laboratory of Mesoscale Severe Weather(MOE) School of the Atmospheric SciencesNanjing University163 Xianlin RoadNanjing 210046China Yubei Meteorological Office of Chongqing Chongqing 401147China Chongqing Institute of Meteorological Sciences Chongqing 401147China

As a follow-up of a previously published article on the contribution of tropical waves,this study explores the evolution of the mid-tropospheric mesoscale cyclonic vortex(MV)during the formation of Typhoon Megi(2010)with a successful cloud-resolving *** is found that the formation and intensification of the MV were related to the deep convection and subsequent stratiform precipitation,while the weakening of the MV was related to the shallow *** the upward transport of vorticity related to the deep convection and the horizontal convergence associated with the stratiform precipitation contributed to the formation and intensification of the *** though the latter was dominant,the former could not be ignored,especially in the early stage of the *** MV played dual roles in the formation of *** the one hand,the formation and intensification of MV were primarily associated with the stratiform precipitation,which induced the low-level divergence inhibiting the spin-up of the near-surface cyclonic *** the other hand,the coupled low-level cold core under the MV benefited the accumulation of the convective available potential energy(CAPE),which was favorable for the convective activity.A sensitivity experiment with the evaporative cooling turned off indicated that the development of the MV retarded the genesis process of Megi.

关键词： Typhoon shallow divergence

Mean square stability for Markov jump Boolean networks

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Science China(Information Sciences) 2020年第1期63卷 190-199页

作者： Liqing WANG Mei fang zheng-Guang WU State Key Laboratory of Industrial Control Technology Institute of Cyber-Systems and ControlZhejiang University College of Automation Harbin Engineering University

In this paper, one of the stability definitions of Markov jump Boolean networks(MJBNs), called mean square stability(MSS), is investigated. Some necessary and sufficient conditions are presented to guarantee the MSS of such MJBNs. Moreover, one of the necessary and sufficient conditions for MSS is obtained in terms of linear programming, which implies that MSS is equivalent to global stability with probability 1 for MJBNs. Furthermore, the construction of Lyapunov function is given and also another theorem based on the Lyapunov function is derived to ensure the MSS of MJBNs. Finally, a numerical example is provided to illustrate the profits of our results.

关键词： mean square stability MSS Boolean network BN stochastic stability Markovian jump parameters semi-tensor product STP Lyapunov function

Quantifying in situ N2 fluxes from an intensively managed calcareous soil using the 15N gas-flux method

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Journal of Integrative Agriculture 2022年第9期21卷 2750-2766页

作者： LIU Yan WANG Rui PAN Zhan-lei zheng Xun-hua WEI huan-huan ZHANG Hong-rui MEI Bao-ling QUAN Zhi fang Yun-ting JU Xiao-tang State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of Sciences(CAS)Beijing 100029P.R.China College of Earth and Planet Science University of Chinese Academy of SciencesBeijing 100049P.R.China College of Resources and Environmental Sciences China Agricultural UniversityBeijing 100193P.R.China School of Ecology and Environment Inner Mongolia UniversityHohhot 010021P.R.China CAS Key Laboratory of Forest Ecology and Management Institute of Applied EcologyChinese Academy of SciencesShenyang 110164P.R.China College of Tropical Crops Hainan UniversityHaikou 570228P.R.China

Denitrification-induced nitrogen(N) losses from croplands may be greatly increased by intensive ***,the accurate quantification of these losses is still challenging due to insufficient available in situ measurements of soil dinitrogen(N) *** carried out two one-week experiments in a maize-wheat cropping system with calcareous soil using theN gas-flux(NGF) method to measure in situ Nfluxes following urea *** ofN-labeled urea(99 atom%,130-150 kg N ha) were followed by irrigation on the 1 st,3 rd,and 5 th days after fertilization(DAF 1,3,and 5,respectively).The detection limits of the soil Nfluxes were 163-1 565,81-485,and 54-281 μg N mhfor the two-,four-,and six-hour static chamber enclosures,*** Nfluxes measured in 120 cases varied between 159 and 2 943(811 on average) μg N *** were higher than the detection limits,with the exception of only two *** Nfluxes at DAF 3 were significantly higher(by nearly 80%(P<0.01)) than those at DAF 1 and 5 in the maize experiment,while there were no significant differences among the irrigation times in the wheat *** Nfluxes and the ratios of nitrous oxide(NO) to the NO plus Nfluxes following urea application to maize were approximately 65% and 11 times larger,respectively(P<0.01),than those following urea application to *** differences could be mainly attributed to the higher soil water contents,temperatures,and availability of soil N substrates in the maize experiment than in the wheat *** study suggests that theNGF method is sensitive enough to measure in situ Nfluxes from intensively fertilized croplands with calcareous soils.

关键词： N2 fluxes 15N gas-flux method N2O/(N2O+N2)ratios detection limit intensive cropping system

Synthesis, structure and conformation of 1,3-difluorotetraphenyl benzene

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Chinese Journal of Chemistry 1996年第2期14卷 160-166页

作者： zheng, ZR Pan, YM Liu, WG huan, ZW NANKAI UNIV DEPT CHEMNATL KEY LAB ELEMENTOORGAN CHEMTIANJIN 300071PEOPLES R CHINA

The compound trifluoroiodomethane can be activated to react with the electron donor, 1,4-dilithiotetraphenyl butadiene, by means of electron transfer catalysis (ETC). The structure of the product, 1,3-difluorotetraphenyl, benzene (1), was determined by MS, NMR, and X-ray single crystal diffraction. The conformations of compound 1 and its derivatives were analysized by molecular mechanics.

关键词： tetraphenylbenzene conformation molecular mechanics

PIFs‑and COP1‑HY5‑mediated temperature signaling in higher plants

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Stress Biology 2022年第1期2卷 270-283页

作者： Yeting Bian Li Chu huan Lin Yaoyao Qi zheng fang Dongqing Xu State Key Laboratory of Crop Genetics and Germplasm Enhancement National Center for Soybean ImprovementCollege of AgricultureNanjing Agricultural UniversityNanjing 210095China

Plants have to cope with the surrounding changing environmental stimuli to optimize their physiological and devel-opmental response throughout their entire life *** and temperature are two critical environmental cues that fluctuate greatly during day-night cycles and seasonal *** two external signals coordinately control the plant growth and *** spectrum of light signals are perceived by a group of wavelength-specific photoreceptors in *** and COP1-HY5 are two predominant signaling hubs that control the expression of a large number of light-responsive genes and subsequent light-mediated development in *** parallel,plants also transmit low or warm temperature signals to these two regulatory modules that precisely modulate the responsive-ness of low or warm *** core component of circadian clock ELF3 integrates signals from light and warm temperatures to regulate physiological and developmental processes in *** this review,we summarize and discuss recent advances and progresses on PIFs-,COP1-HY5-and ELF3-mediated light,low or warm temperature signaling,and highlight emerging insights regarding the interactions between light and low or warm temperature signal transduction pathways in the control of plant growth.

关键词： Light signaling Low temperature Warm temperature phyB PIFs COP1 HY5 ELF3