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Radar target recognition based on micro-Doppler effect

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Optoelectronics Letters 2008年第6期4卷 456-459页

作者： DONG Wei-guang li Yan-jun College of Astronautics Northwestern Polytechnical University Xi ＇an 710072 China

Mechanical vibration of target structures will modulate the phase function of radar backscattering,and will induce the frequency modulation of returned signals from the target. It generates a side bands of the target body Doppler frequency shift,which is helpful for target recognition. Based on this,a micro-Doppler atomic storehouse is built for the target recognition,and four kinds of common classifiers are used separately to perform the classified recognition. The simulation experimental results show that this method has high recognition rate above 90%.

关键词：雷达目标显微多普勒效应信息处理后向散射

Crystallization Kinetics and the Fine Morphological Evolution of Poly(ethylene oxide)/Ionic liquid Mixtures

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Chinese Journal of Polymer Science 2017年第11期35卷 1402-1414页

作者： Wen-ze li 牛艳华 Chen-ting Zhou Huan Luo guang-xian li College of Polymer Science and Engineering State Key Laboratory of Polymer Materials Engineering of ChinaSichuan University

Abstract The overall crystallization kinetics and spherulite morphologies of miscible poly（ethylene oxide）（PEO）/1-butyl-3- methylimidazolium hexafluorophosphate （[BMIM][PF6]） mixtures were studied by differential scanning calorimetry （DSC）, polarized optical microscopy （POM） and rheological measurements. The finer crystal structures were further detected by wide angle X-ray diffraction （WAXD） and small angle X-ray scattering （SAXS）. Crystallization of PEO is largely suppressed by [BMIM][PF6] addition especially at higher ionic liquid （IL） concentrations above 20 wt%. Both the overall crystallization rate and the spherulite growth decrease with the increase of IL content and crystallization temperature; however, the crystallization mechanism keeps unchanged as evidenced by the similar Avrami exponent n and WAXD results. The addition of [BMIM][PF6] could induce more nuclei to some extent, but the induction time of crystallization is evidently prolonged, and a linear to non-linear transition of the spherulite growth （R ∝ t to R ∝t^1/2） can be observed. At higher IL concentration, the spherulite texture changes apparently from particular serrated to branch surface due to the diffusion-controlled growth and the dilution effect, which also as a main factor contributes to the increasing trend of the long period of crystals.

关键词： PEO [BMIM][PF6] Crystallization kinetics Spherulite morphologies

The Gossypium raimondii Genome,a Huge Leap Forward in Cotton Genomics

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Journal of Integrative Plant Biology 2013年第7期55卷 570-571页

作者： Yu-Xian Zhu Fu-guang li Issue Editor College of life Sciences Peking University Beijing Issue Editor Cotton Research Institute Chinese Academy of Agricultural Sciences Henan

Cotton, in the Gossypium genus, constitutes five tetraploid （2n = 4x = 52） and 45 diploid （2n = 2x = 26） species, which are believed to have originated from a common ancestor 5-10 million years ago （MYA）. Upland cotton （G. hirsutum, AADD, 2n = 4x = 52）, which is responsible for over 90% of the world＇s cotton lint production, is thought to have undergone an allopolyploidization event about 1-2 MYA involving both A and D genome species （Wendel and Albert 1992）. The progenitor of G. raimondii （DD, 2n = 2x = 26） is considered the contributor of the D subgenome, while ancestors of G. arboreum （AA, 2n = 2x = 26） may have contributed the A subgenome to G. hirsutum （Sunilkumar et al. 2006; Chen et al. 2007）.

关键词： The Gossypium raimondii Genome,a Huge Leap Forward in Cotton Genomics gene NAC

Tailoring sintering-resistant thermal barrier coatings by considering critical healing width of two-dimensional interlamellar pores

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Journal of Advanced Ceramics 2023年第7期12卷 1317-1330页

作者： guang-Rong li Tao liu Xiao-Tao Luo Guan-Jun Yang Chang-Jiu li State Key Laboratory for Mechanical Behavior of Materials School of Materials Science and EngineeringXi'an Jiaotong UniversityXi'an 710049China

Large degradation in thermal insulation and strain tolerance is a main headache and a primary cause of the failure for plasma-sprayed thermal barrier coatings(TBCs)during *** mechanism behind such degradation is the healing of interlamellar pores formed by multiple connections between edges of a pore,which significantly speeds up healing during thermal *** objective of this study is to obtain sintering-resistant TBCs by tailoring the width of interlamellar pores to avoid multiple ***,the mechanism responsible for the multiple connections was *** splat surfaces before and after thermal treatments were characterized via an atomic force microscope(AFM).The roughening of the pore surface occurs during thermal exposure,along with the grain growth inside the ***,the local surface height increases,which causes multiple connections and healing of the interlamellar ***,critical widths of the interlamellar pores for avoiding the multiple connections during thermal exposure are established by correlating the extent of surface roughening with the growth of individual *** height increase of the splat surface and the growth of the grain size(D)were found to increase with the exposure temperature and duration.A relationship linking the height increase and the growth of the grain size induced by thermal exposure in plasma-sprayed ceramic splats was ***,composite TBCs were prepared to form wide interlamellar pores in the *** this design,the increases in the thermal conductivity(λ)and the elastic modulus(E)can be prevented to a large ***,sintering-resistant TBCs that maintain high thermal insulation and strain tolerance,even afer long thermal exposure,can be created.

关键词： thermal barrier coatings(TBCs) air plasma spraying(APS) multiple connections grain growth sintering-resistant structure

Relationship between crystallographic structure of complex inclusions MgAl_(2)O_(4)/Ti2O_(3)/MnS and improved toughness of heat-affected zone in shipbuilding steel

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Journal of Iron and Steel Research International 2022年第8期29卷 1277-1290页

作者： Yan Wang li-guang Zhu Jin-xia Huo Qing-jun Zhang Yao-guang Wu Wei Chen Shuo-ming Wang College of Metallurgy and Energy North China University of Science and TechnologyTangshan 063210HebeiChina College of Materials Science and Engineering Hebei University of Science and TechnologyShijiazhuang 050018HebeiChina China Analysis and Testing Center North China University of Science and TechnologyTangshan 063210HebeiChina MCC Capital Engineering&Research Incorporation limited Metallurgical Engineering Consulting and Design DivisionBeijing 100176China

In accordance with the minimum degree of disregistry mechanism in oxide metallurgy, the intragranular acicular ferrite (IAF) generated by microalloying elements in austenite was studied. Herein, the effect of Mg treatment on the microstructure and toughness of the heat-affected zone (HAZ) in shipbuilding steel was investigated. Mg treatment produced inclusions that influenced the formation of acicular ferrite in the microstructure. This refined the HAZ microstructure and improved its toughness. Electron backscatter diffraction was used to determine the oxides of titanium and the MgO Al_(2)O_(3) or MgAl_(2)O_(4) complex inclusions that induced the formation of IAF. MnS precipitated on MgAl_(2)O_(4) on a specific habit plane and in a specific direction. MnS had a specific orientation relationship with MgAl_(2)O_(4), i.e., f100gMgAl_(2)O_(4) //{100}MnS. The 35-mm-thick plate obtained in the industrial test after welding at a welding heat input of 120 kJ/cm had an average impact absorbed energy of 282.7 J at - 40 ℃ and 2 mm from the weld joint in the HAZ. The twodimensional disregistry index between inclusions can be used as the basis for controlling their distribution and adsorption force. Microalloy addition in the order of Al-Mg-Ti is key to obtaining abundant dispersion and fine nucleation in austenite.

关键词： High heat input welding Mg treatment Disregistry mechanism Heat-affected zone

Characterization on the Microstructures of Brominated Natural Rubber from Latex

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Journal of Wuhan University of Technology(Materials Science) 2019年第1期34卷 201-206页

作者： XUE Xinghua liU Yafei HAN Xiuping li guang WANG Zhiyong College of Materials and Chemical Engineering Hainan University Department of Chemistry and Physics Troy University

To elucidate the mechanism of brominated natural rubber(BNR), eight BNR samples with different bromine content were prepared from latex in different bromination time, and the microstructures were characterized by Fourier transform infrared spectroscopy(FTIR) and ~1H-NMR spectroscopy, respectively. The hardness of BNR increased and its nature transformed from elastomer to resin with the increase of bromine content. Unlike chlorinated natural rubber(CNR), FTIR showed that there were no carbonyl groups on the molecular chains of BNR. ~1H-NMR spectroscopy revealed that the reaction activity of bromine and the secondary hydrogen atom of BNR were much higher than those of the primary one. The brominated substitution took place in the hydrogen atom of CH_3 and CH_2 groups firstly, then in the late period of bromination the bond of C=C was transferred to the saturated bond of C-C due to the Markovnikov addition of hydrogen bromide. Based on these findings, the mechanism of BNR from latex could be deduced as a free radical reaction and the detailed bromination process was presented.

关键词： natural rubber bromination microstructure mechanism radical reaction

The Contribution of the Nearest-Neighborhood Interaction to the Persistent Current in a Mesoscopic Ring Studied by a New Model

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Communications in Theoretical Physics 2001年第12期36卷 715-722页

作者： HE guang-Ping li Hua-Zhong MA Zhong-Shui Advanced Research Center Zhongshan University Guangzhou 510275 China Advanced Research Center Zhongshan University Guangzhou 510275 China Advanced Research Center Zhongshan University Guangzhou 510275 China

We propose an effective description of the interaction between the nearest-neighboring particles in a continuum theory. The contributions of the electron-electron interaction to the persistent current in 1D strongly correlating mesoscopic rings with or without impurities are analyzed. It is shown that the nearest-neighborhood int eraction gives significant contributions to the current and correlation functions. The enhance of the theoretical value of current magnitude is observed at finite temperature in the presence of the impurity scattering. The statistical property of the persistent current over random impurity distribution is also discussed. It is found that the exponential law of the persistent current for a non-interacting system will remain in an interacting one, as long as the interactions between nonnearest-neighborhoods are excluded.

关键词： strongly correlated electron systems, persistent current, mesoscopic systems

On the Stability of a Mixed Functional Equation Deriving from Additive, Quadratic and Cubic Mappings

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Acta Mathematica Sinica,English Series 2014年第6期30卷 1033-1049页

作者： li guang WANG Kun Peng XU Qiu Wen liU School of Mathematical Sciences Qufu Normal University Zaozhuang Economics School

In this paper, we investigate the general solution and the Hyers–Ulam stability of the following mixed functional equation f（2x ＋ y）＋ f（2x- y） = 2f（2x）＋ 2f（x ＋ y）＋ 2f（x- y）- 4f（x）- f（y）- f（-y）... 详细信息

关键词： Additive mapping quadratic mapping cubic mapping Hyers–Ulam stability

Atomic Hardy-type Spaces between H1 and L1 on Metric Spaces with Non-doubling Measures

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Acta Mathematica Sinica,English Series 2011年第12期27卷 2445-2468页

作者： li guang liU Da Chun YANG Dong Yong YANG School of Mathematical Sciences Beijing Normal UniversityLaboratory. of Mathematics and Complex Systems Ministry of EducationBeijing 100875 P. R. China

Let （y, d, dλ） be （Rn, ｜·｜,μ）, where ｜·｜ is the Euclidean distance, μ is a nonnegative Radon measure on Rn satisfying the polynomial growth condition, or the Gauss measure metric space （Rn, ｜·｜,dγ）, or the space （S, d, p）, where S - Rn×R＋ is the （ax ＋ b）-group, d is the left-invariant Riemannian metric and p is the right Haar measure on S with exponential growth. In this paper, the authors introduce and establish some properties of the atomic Hardy-type spaces {Xs（Y））0〈s≤∞ and the BM0-type spaces {BM0（y, s）}0〈s≤∞. Let Hi（Y） be the known atomic Hardy space and L01（y） the subspace of f ∈ L1（Y） with integral 0. The authors prove that the dual space of Xs（Y） is SM0（Y,s） when s∈ （0, ∞）, Xs（Y） = H1（Y） when s ∈ （0, 1], and X∞（y） = L01（Y）（or L1（Y））. As applications, the authors show that if T is a linear operator bounded from H1 （Y） to L1 （Y） and from L1（y） to L1,∞（Y）, then for all r ∈ （1, ∞） and s ∈ （r, ∞], T is bounded from Xr（y） to the Lorentz space L1,8（y）, which applies to the Calderon-Zygmund operator on （Rn, ｜·｜,μ）, the imaginary powers of the 0rnstein-Uhlenbeck operator on （Rn, ｜·｜,dγ） and the spectral operator associated with the spectral multiplier on （S, d, p）. All these results generalize the corresponding results of Sweezy, Abu-Shammala and Torchinsky on Euclidean spaces.

关键词： Non-doubling measure polynomial growth Gauss measure (ax + b)-group atomicHardy-type space BMO-type space operator