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| 1 | Joint calibration algorithm for gain-phase and mutual coupling errors in uniform linear array显示文摘The effect of gain-phase perturbations and mutual coupling significantly degrades the performance of digital array radar(DAR). This paper investigates array calibration problems in the scenario where the true locations of auxiliary sources deviate from nominal values but the angle intervals are known. A practical algorithm is proposed to jointly calibrate gain-phase errors and mutual coupling errors. Firstly, a simplified model of the distortion matrix is developed based on its special structure in uniform linear array(ULA). Then the model is employed to derive the precise locations of the auxiliary sources by one-dimension search. Finally, the least-squares estimation of the distortion matrix is obtained. The algorithm has the potential of achieving considerable improvement in calibration accuracy due to the reduction of unknown parameters. In addition,the algorithm is feasible for practical applications, since it requires only one auxiliary source with the help of rotation platforms. Simulation results demonstrate the validity, robustness and high performance of the proposed algorithm. Experiments were carried out using an S-band DAR test-bed.The results of measured data show that the proposed algorithm is practical and effective in application. | Li Weixing Lin Jianzhi Zhang Yue Chen Zengping | 2016 | Chinese Journal of Aeronautics2016，29，4： | 9 |
| 2 | Parameter estimation of chirp signal under low SNR显示文摘Aiming at solving the problem of great difficulty and low accuracy existing in parameter estimation of chirp signal under low signal-to-noise ratio(SNR) condition, an algorithm of accurate parameter estimation of chirp signal is proposed. First, the algorithm extracts ridge frequency of chirp signal based on Short Time Fourier Transform. Second, the protruding glitch frequencies are eliminated through median filter with proper size and the smoothing frequencies are obtained corresponding to the time. Third, the frequency time frequencymodulated(FM) line is fitted coarsely by the least-square linear fitting method, and some frequency points are removed, which are far away from the FM line. Repeat the process several times until the sample correlation coefficient of the fitted line is in high degree when the optimum chirp line is fitted out, so chirp rate and initial frequency are obtained. Simulation shows that the correct rate of parameter estimation is very high. When SNR is not less than –17 d B, the correct rate is 100%, and when the SNR is –18 d B, the correct rate is still capable of up to 99%. This algorithm has a lower SNR threshold of about –17 d B. When the SNR is greater than threshold,parameter estimation accuracy is close to Cramer Rao low bound(CRLB), higher than parameter estimation based on the phase field method. Measured data experiments show that the algorithm can reasonably fit the chirp line of measured chirp signal, which better characterizes the FM features of chirp signal. | WANG JinZhen SU ShaoYing CHEN ZengPing | 2015 | Science China(Information Sciences)2015，58，2： | 5 |
| 3 | Long term integration of radar signals with unknown Doppler shift for ubiquitous radar显示文摘Ubiquitous radar is a new radar system that provides continuous and uninterrupted multifunction capability within a coverage volume. Continuous coverage from close-in 'pop-up' targets in clutter to long-range targets impacts selection of waveform parameters. The coherent processing interval (CPI) must be long enough to achieve a certain signal-to-noise ratio (SNR) that ensures the efficiency of detection. The condition of detection in the case of low SNR is analyzed, and three different cases that would occur during integration are discussed and a method to determine the CPI is presented. The simulation results show that targets detection with SNR as low as -26 dB in the experimental system can possibly determine the CPI. | Qinglong Bao Zengping Chen Yue Zhang Jian Yang | 2011 | Journal of Systems Engineering and Electronics2011，22，2： | 4 |
| 4 | Design and simulation of digital channelized receivers in fractional Fourier domain显示文摘An approach is proposed to realize a digital channelized receiver in the fractional Fourier domain(FRFD) for signal intercept applications.The presented architecture can be considered as a generalization of that in the traditional Fourier domain.Since the linear frequency modulation(LFM) signal has a good energy concentration in the FRFD,by choosing an appropriate fractional Fourier transform(FRFT) order,the presented architecture can concentrate the broadband LFM signal into only one sub-channel and that will prevent it from crossing several sub-channels.Thus the performance of the signal detection and parameter estimation after the sub-channel output will be improved significantly. The computational complexity is reduced enormously due to the implementation of the polyphase filter bank decomposition,thus the proposed architecture can be realized as efficiently as in the Fourier domain.The related simulation results are presented to verify the validity of the theories and methods involved in this paper. | Pengfei Tang Bin Yuan Qinglong Bao Zengping Chen | 2013 | Journal of Systems Engineering and Electronics2013，24，1： | 3 |
| 5 | Fuzzy linear discriminant analysis for chemical data sets显示文摘 | Chen Zengping Jiang Jianhui Li Yang | 1999 | Chemometrics and Intel- ligent Laboratory Systems1999，45，12： | 1 |
| 6 | Micro- Doppler analysis and separation based on complex local mean decomposition for aircraft with fast-rotating parts in ISAR imaging显示文摘 | YUAN Bin CHEN Zengping and XU Shiyou | 2014 | IEEE Transactions on Geoscience and Remote Sensing2014，52，2： | 1 |
| 7 | Geochemical distribution, fractionation, and sources of heavy metals in dammed-river sediments: the Longjiang River, Southern China显示文摘In the present study, six sediment cores were collected from six river-dammed reservoirs to reveal the geochemical distribution of heavy metals(As, Cd, Pb, Sb,and Zn) in the Longjiang River, South China, which is highly impacted by nonferrous metal mining and smelting activities. The sediments were geochemically characterized, combining geochemical analysis, sequential extractions, and210 Pb chronology. The results indicated that the river sediments were severely polluted by heavy metals in the order of Cd [ Zn & Pb & Sb [ As. These heavy metals generally exhibited relatively low enrichment in the upstream sediments because of the limited anthropogenic impact, but their abundances drastically increased in the midstream sediments due to local smelting activities. In downstream sediments, the heavy metal concentrations(except for Cd) decreased, owing to the effect of dam interception and detrital inputs. Cadmium levels tended to increase in downstream sediments, which were attributed to the intensive discharge of Cd during the pollution event in 2012. The sedimentary records were traced back to1985, and a significant decrease of heavy metal enrichments could be found after the year 2000, suggesting the enhancement of environmental management in this period.The statistical results indicated that local metal smelting and mining activities were the main anthropogenic contributors for the enrichment of heavy metals in the dammed-river sediments. High enrichment factor and nonresidual fractions of heavy metals in local sediments may pose a direct threat to aquatic organisms. Cd presents significant danger because of its extreme enrichment and high labile fractions. | Xiaolong Lan Zengping Ning Yizhang Liu Qingxiang Xiao Haiyan Chen Enzong Xiao Tangfu Xiao | 2019 | Acta Geochimica2019，38，2： | 1 |
| 8 | Process analytical technologies and real time process control a review of some spectroscopic issues and challenges显示文摘 | Zengping Chen David Lovett Julian Morris | 2011 | Journal of Process Control2011，，10： | 1 |
| 9 | Fuzzy linear cliscriminant analysis for chemical data sets 显示文摘 | CHEN Zengping JIANG Jianhui LI Yizeng | 1999 | Chemometrics and Intelligent Laboratory Systems1999，45，12： | 1 |
| 10 | Non-linear Mapping Using Real-valued Genetic Algorithm显示文摘 | CHEN Zengping JIANG Jianhui LI Yang | 1999 | Chemometrics and Intelligent Laboratory Systems1999，45，12： | 1 |
| 11 | Raman and X-ray photoelectron scattering study of lanthanum-doped strontium bismuth titanate显示文摘 | ZHU Jun CHEN Xiaobing ZHANG Zengping | 2005 | Acta Mater2005，53，： | 1 |
| 12 | Bistatic weak target detection method using non-cooperative air surveillance radar显示文摘At present, most of the passive radar system researches utilize FM radios, TV broadcasts, navigation satellites,etc. as illuminators. The transmitted signals are not specifically designed radar waveforms. In this work, the frequency agile, phased array air surveillance radar(ASR) is used as the illuminator of opportunity to detect the weak target. The phased array technology can help realize beam agility to track targets from different aspects simultaneously. The frequency agility technology is widely employed in radar system design to increase the ability of anti-jamming and increase the detection probability. While the frequency bandwidth of radar signals is usually wide and the range resolution is high, the range cell migration effect is obvious during the long time integration of non-cooperative bistatic radar. In this context, coherent integration methods are not applicable. In this work, a parametric non-coherent integration algorithm based on task de-interweaving is proposed. Numerical experiments verify that this is effective in weak target detection. | Dinghe Wang Qinglong Bao Ruiqi Tian Zengping Chen | 2015 | Journal of Systems Science & Complexity2015，28，5： | 0 |
| 13 | Hybrid integration method for highly maneuvering radar target detection based on a Markov motion model显示文摘To detect highly maneuvering radar targets in low signal-to-noise ratio conditions, a hybrid long-time integration method is proposed, which combines Radon-Fourier Transform(RFT), Dynamic Programming(DP), and Binary Integration(BI), named RFT-DP-BI. A Markov model with unified range-velocity quantification is formulated to describe the maneuvering target’s motion. Based on this model, long-time hybrid integration is performed. Firstly, the whole integration time is divided into multiple time segments and coherent integration is performed in each segment via RFT. Secondly, non-coherent integration is performed in all segments via DP. Thirdly, 2/4 binary integration is performed to further improve the detection performance. Finally, the detection results are exported together with target range and velocity trajectories. The proposed method can perform the long-time integration of highly maneuvering targets with arbitrary forms of motion.Additionally, it has a low computational cost that is linear to the integration time. Both simulated and real radar data demonstrate that it offers good detection and estimation performances. | Yingxiao ZHAO Zengping CHEN Yue ZHANG Jie CHEN Jiong YANG Yunsheng XIONG | 2020 | Chinese Journal of Aeronautics2020，33，6： | 0 |
| 14 | Broadband ground motion simulation using a hybrid approach of the May 21, 2021 M7.4 earthquake in Maduo, Qinghai, China显示文摘In this study,the broadband ground motions of the 2021 M7.4 Maduo earthquake were simulated to overcome the scarcity of ground motion recordings and the low resolution of macroseismic intensity map in sparsely populated high-altitude regions.The simulation was conducted with a hybrid methodology,combining a stochastic high-frequency simulation with a low-frequency ground motion simulation,from the regional 1-D velocity structure model and the Wang WM et al.(2022)source rupture model,respectively.We found that the three-component waveforms simulated for specific stations matched the waveforms recorded at those stations,in terms of amplitude,duration,and frequency content.The validation results demonstrate the ability of the hybrid simulation method to reproduce the main characteristics of the observed ground motions for the 2021 Maduo earthquake over a broad frequency range.Our simulations suggest that the official map of macroseismic intensity tends to overestimate shaking by one intensity unit.Comparisons of simulations with empirical ground motion models indicate generally good consistency between the simulated and empirically predicted intensity measures.The high-frequency components of ground motions were found to be more prominent,while the low-frequency components were not,which is unexpected for large earthquakes.Our simulations provide valuable insight into the effects of source complexity on the level and variability of the resulting ground motions.The acceleration and velocity time histories and corresponding response spectra were provided for selected representative sites where no records were available.The simulated results have important implications for evaluating the performance of engineering structures in the epicentral regions of this earthquake and for estimating seismic hazards in the Tibetan regions where no strong ground motion records are available for large earthquakes. | Yijun Liu Xiaofen Zhao Zengping Wen Jie Liu Bo Chen Chunyao Bu Chao Xu | 2023 | Earthquake Science2023，36，3： | 0 |
| 15 | Two-step calculation method to enable the ecological and human health risk assessment of remediated soil treated through thermal curing显示文摘The centralized utilization of heavy-metal-contaminated soil has become the main strategy to remediate brownfield-site pollution.However,few studies have evaluated the ecological and human health risks of reusing these remediated soils.Considering Zn as the target metal,systematic pHdependent leaching and the Community Bureau of Reference(BCR)extraction were conducted at six pH values(pH=2,4,6,8,10,12)for the remediated soil treated through thermal curing.The pHdependent leaching results showed that with the formation of ZnCr2O4 spinel phases,the remediated soil exhibited strong inherent resistance to acidic attack over longer leaching periods.Furthermore,the BCR extraction results showed that the leaching agent pH value mainly affected the acid-soluble fraction content.Moreover,a strong complementary relationship was noted between the leaching and acid-soluble fraction contents,indicating that the sum of these two parameters is representative of the remediated soil risk value.Therefore,we proposed a two-step calculation method to determine the sum of the two heavy metal parameters as the risk value of remediated soil.In contrast to the traditional one-step calculation method,which only uses the leaching content as the risk value,this two-step calculation method can effectively avoid underestimating the risk of remediated soil. | Shaowen Xie Fei Wu Zengping Ning Manjia Chen Chengshuai Liu Qiang Huang Fangyuan Meng Yuhui Liu Jimei Zhou Yafei Xia | 2021 | Soil Ecology Letters2021，3，3： | 0 |
| 16 | Techniques for Radar Imaging Based onMUSIC Algorithm显示文摘At first, the radar target scattering centers model and MUSIC algorithm are analyzed in this paper. How to efficiently set the parameters of the MUSIC algorithms is given by a great deal of simulated radar data in experiments. After that, according to measured data from two kinds of plane targets on fully polarized and high range resolution radar system, the author mainly investigated particular utilization of MUSIC algorithm in radar imaging. And two-dimensional radar images are Generated for two targets measured in compact range. In the end, a conclusion is drew about the relation of radar target scattering pooperties and imaging results. | Guo, Biao Lu, Xiaoying Chen, Zengping | 1999 | Journal of Systems Engineering and Electronics1999，10，1： | 0 |
| 17 | The combined toxicity and mechanism of multi-walled carbon nanotubes and nano copper oxide toward freshwater algae:Tetradesmus obliquus显示文摘Nanoparticles(NPs)are widely used for their special physical properties and released into the natural environment.When two types of NPs exist in the same environment,the presence of one type of NP may affect the properties of the other type of NP.This study investigated the toxic effects of multi-walled carbon nanotubes(MWCNTs)and copper oxide nanoparticles(Cu O NPs)on Tetradesmus obliquus.Both NPs had toxic effects on algae,and the toxic effects of MWCNTs were significantly stronger than Cu O NPs which the 96-hr median effective concentration to algae were 33.8 and 169.2 mg/L,respectively.Oxidative stress and cell membrane damage were the main reasons for the toxicity of NPs to algae,and they were concentration-dependent,and the existence of Cu O NPs in some groups reduced cell membrane damage caused by MWCNTs which may because that Cu O NPs formed heteroaggregation with MWCNTs,reducing the contact of nanoparticles with cell membranes,then reducing physical damage.Scanning electron microscopy(SEM)and transmission electron microscope(TEM)results indicated cell damage,the heteroaggregation of MWCNTs-Cu O NPs and obvious nanoparticles internalization.In some groups,the presence of Cu O NPs significantly reduced reactive oxygen species(ROS)level induced by MWCNTs.However,for the highest concentration group,the ROS level was much higher than that of the two NPs alone treatment groups,which might be related to the high concentration of MWCNTs promoting the internalization of Cu O NPs.MWCNTs and Cu O NPs affected and interacted with each other,causing more complex toxic effects on aquatic organisms. | Rong Fang Jilai Gong Weicheng Cao Zengping Chen Danlian Huang Jun Ye Zhe Cai | 2022 | Journal of Environmental Sciences2022，34，2： | 0 |
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