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| 1 | Narrow-band radar imaging of spinning targets显示文摘According to the characteristics of narrow-band radar echoes from spinning targets,this paper applies the complex-valued back-projection method to image formation.Since it accumulates the sinusoidal phase of spinning scatterers effectively,this method can obtain high resolution imaging.The resolution and required radar pulse repetition frequency (PRF) of this method are deduced.For imaging of fast spinning targets,however,spurious peaks appear due to azimuth down sampling with a low PRF.Therefore,a signal model of azimuth down-sampled echoes is created according to the compressed sensing (CS) theory.Then an imaging method based on orthogonal matching pursuit (OMP) is proposed according to the sparsity nature of ISAR echoes.Finally,the effectiveness of the proposed methods is demonstrated using simulated data. | BAI XueRu SUN GuangCai WU QiSong XING MengDao BAO Zheng | 2011 | Science China(Information Sciences)2011，54，4： | 9 |
| 2 | Parameter estimation of moving targets in the SAR system with a low PRF sampling rate显示文摘In the synthetic aperture radar(SAR)system with low pulse repetition frequency(PRF)sampling,it is difficult for the motion parameters estimation of the moving targets,because of the Doppler spectrum ambiguity and Doppler centroid frequency ambiguity of the echo signals.Considering that moving targets are sparsely distributed in the observed scene,their positions and velocities can be reconstructed by using the compressed sensing(CS)technique.In this paper,the range-walk correction are implemented by the Keystone transform and the sparse range-walk correction(SRWC),then the CS technique is proposed to reconstruct motion parameters by processing the azimuth signals of the moving targets.Experiments using the simulated and real data are performed,and the results confirm the validity of the proposed method. | LIU Yan WU QiSong SUN GuangCai XING MengDao LIU BaoChang BAO Zheng | 2012 | Science China(Information Sciences)2012，55，2： | 5 |
| 3 | Enhanced Fracture Toughness of Pressureless-sintered SiC Ceramics by Addition of Graphene显示文摘To enhance the fracture toughness of pressureless-sintered Si C ceramic, graphene was introduced as an additive. The effects of graphene contents on the fracture toughness, bending strength, micro-hardness,phase compositions, and microstructure evolutions of the Si C ceramics were investigated in detail by scanning electron microscopy, energy dispersive X-ray spectroscopy, and metallographic microscopy. The fracture toughness, bending strength and micro-hardness increased initially, and then decreased with the graphene content increasing from 0 to 5.0 wt%. The highest fracture toughness of 5.65 MPa m1/2was obtained for sample with 1.0 wt% graphene sintered at 2130 °C for 1 h in Ar, which was about 22.6% higher than that of Si C sample without graphene. In addition, the highest bending strength and microhardness of 434.14 MPa and 29.21 GPa corresponded to the Si C samples with graphene content of 0.5wt% and 2.0 wt%, respectively. | Qisong Li Yujun Zhang Hongyu Gong Haibin Sun Wenjie Li Li Ma Yanshuang Zhang | 2016 | Journal of Materials Science & Technology2016，32，7： | 5 |
| 4 | Effects of AlN on the densification and mechanical properties of pressureless-sintered SiC ceramics显示文摘In the present work, Si C ceramics was fabricated with Al N using B_4 C and C as sintering aids by a solid-state pressureless-sintered method. The effects of Al N contents on the densification, mechanical properties, phase compositions, and microstructure evolutions of as-obtained Si C ceramics were thoroughly investigated. Al N was found to promote further densification of the Si C ceramics due to its evaporation over 1800 °C,transportation, and solidification in the pores resulted from Si C grain coarsening. The highest relative density of 99.65% was achieved for Si C sample with 15.0 wt% Al N by the pressureless-sintered method at 2130 °C for 1 h in Ar atmosphere. Furthermore, the fracture mechanism for Si C ceramics containing Al N tended to transfer from single transgranular fracture mode to both transgranular fracture and intergranular fracture modes when the sample with 30.0 wt% Al N sintered at 1900 °C for 1 h in Ar. Also, Si C ceramics with 30.0 wt% Al N exhibited the highest fracture toughness of 5.23 MPa m^(1/2) when sintered at 1900 °C. | Qisong Li Yujun Zhang Hongyu Gong Haibin Sun Yanxia Zhai Weiya Zhu Jie Jing | 2016 | Progress in Natural Science:Materials International2016，26，1： | 2 |
| 5 | The secretory pathway and the actomyosin motility system are required for plasmodesmatal localization of the P7-1 of rice black-streaked dwarf virus显示文摘 | Zongtao Sun Shanglin Zhang Li Xie Qisong Zhu Zilong Tan Jing Bian Liying Sun Jianping Chen | 2013 | Archives of Virology2013，，5： | 1 |
| 6 | EEMD and bidimensional RLS to suppress physiological interference for heterogeneous distribution in fNIRS study显示文摘Near-infrared spectroscopy(NIRS)can provide the hemodynamics information based on the hemoglobin concentration representing the blood oxygen metabolism of the cerebral cortical,which can be deployed for the cerebral function study.However,NIRS-based cerebral function detection accuracy can be signi¯cantly in°uenced by the physiological activities such as cardic cycle,respiration,spontaneous low-frequency oscillation and ultra-low frequency oscillation.The distribution difference of the capillary,artery and vein leads to the heterogeneity feature of the cerebral tissues.In the case that the heterogeneity is not serious,good detection accuracy and stable performance can be achieved through the regression analysis as the reference signal can well represent the interference in the measurement signal when conducting the multi-distance measurement approach.The direct use of the reference signal to estimate the interference is not able to achieve good performance in the case that the heterogeneity is serious.In this study,the cerebral function activity signal is extracted using recursive least square(RLS)method based on the multi-distance measurement method in which the reference signal is processed by ensemble empirical mode decomposition(EEMD)algorithm.The temporal and dimensional correlation of the neighboring sampling values are applied to estimate the interference in the measurement signal.Monte Carlo simulation based on a heterogeneous model is adopted here to investigate the effectiveness of this methodology.The results show that this methodology can effectively suppress the physiological interference and improve the detection accuracy of cerebral activity signal. | Yan Zhang Dan Liu Qisong Wang Xin Liu Chunling Yang Jinwei Sun Jingyang Lu Peter Rolfe | 2018 | Journal of Innovative Optical Health Sciences2018，，6： | 1 |
| 7 | Magnetic properties,crystalline and magnetic microstructures of dual-main-phase(Nd,Ce)-Fe-B sintered magnets显示文摘The(Nd,Ce)-Fe-B sintered magnets were prepared by a dual-main-phase(DMP)process under the same conditions using different combinations of Nd-Fe-B with Ce-Fe-B and(Nd,Ce)-Fe-B strips.The crystalline and magnetic microstructures of DMP(Nd,Ce)-Fe-B magnets with the remanence of 11.92-12.68 kGs,the intrinsic coercivity of 3.97-5.31 kOe,and the maximum energy product of 23.08-32.99 MGOe have been investigated.Magnetic force microscope(MFM)investigations reveal that the DMP(Nd,Ce)-Fe-B magnets show maze-like patterns,which are like that of standard anisotropy Nd-Fe-B sintered magnets by and large.However,much finer domain structures mixing with coarse ones can be observed obviously in DMP(Nd,Ce)-Fe-B sintered magnets.The size distribution of the domain width of the DMP(Nd,Ce)-Fe-B magnet is not uniform obviously.The average domain width is W=0.912μm,and the fine domain width has only 0.216μm.The smaller domain width and more branch domain patterns exist in poorer coercivity DMP magnets.This is caused by the non-uniform Ce composition of poorer property DMP magnets and the grain boundary microstructure that is not conducive to improving the coercivity.Furthermore,it is found that some domains of rare-earth-rich grain boundary phases exhibit the characteristics of plate-like patterns rather than no-contrast by using MFM,indicating their ferromagnetism.Obvious correlations between the crystalline microstructure,chemical composition of phases,and magnetic structure were demonstrated for the DMP magnets. | Yifei Xiao Lele Zhang Tao Liu Xiaolong Song Qisong Sun Yikun Fang Minggang Zhu Wei Li | 2023 | Journal of Materials Science & Technology2023，，31： | 0 |
| 8 | Superior corrosion resistance and corrosion mechanism of dual-main-phase (Ce_(15)Nd_(85))_(30)Fe_(bal)B_(1)M magnets in different solutions显示文摘The electrochemical corrosion behavior of both (Ce_(15)Nd_(85))_(30)Fe_(bal)B_(1)M sintered magnets prepared with dual-main-phase method and N45-type magnets was studied in 3.5 wt% NaCl,1.1 wt% NaH_(2)PO_(4),and 2.5 wt% NaOH solutions,respectively.The (Ce_(15)Nd_(85))_(30)Fe_(bal)B_(1)M sintered magnets perform superior corrosion resistance than N45-type magnets in the tested solutions.In general,two kinds of magnets exhibit the best corrosion resistance property in 2.5 wt% NaOH solution,while the worst in 3.5 wt% NaCl solution.Microstructures of samples before and after corrosion were investigated.With the addition of Ce by means of dual-main-phase method,which is conducive to facilitating low-temperature sintering and grain refinement,uniform grain size and(Nd,Ce)-rich phase distribution form,give rise to narrow and thin corrosion channels.Moreover,the corrosion rate of the(Nd,Ce)-rich phase is lower than that of Nd-rich one.Acco rdingly,corro sion re sistance of (Ce_(15)Nd_(85))_(30)Fe_(bal)B_(1)M sintered magnet is superior when compared with the commercial N45-type magnet which has comparable magnetic properties. | Yaping Wu Minggang Zhu Qisong Sun Lele Zhang Peng Shen Yikun Fang Wei Li | 2023 | Journal of Rare Earths2023，41，1： | 0 |
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