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Optimal crater landmark selection based on optical navigation performance factors for planetary landing

Chinese Journal of Aeronautics 2023年第3期36卷 254-270页

作者： yi xiu Shengying ZHU Rui XU Maodeng LI School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Key Laboratory of Autonomous Navigation and Control for Deep Space Exploration Ministry of Industry and Information TechnologyBeijing 100081China Key Laboratory of Dynamics and Control of Flight Vehicle Ministry of EducationBeijing 100081China Science and Technology on Space Intelligent Control Laboratory Beijing Institute of Control EngineeringBeijing 100091China

Planetary craters are natural navigation landmarks that widely exist and are easily *** navigation based on crater landmarks has become an important autonomous navigation method for planetary *** to the increase in observed crater landmarks and the limitation of onboard computation,the selection of good crater landmarks has gradually become a research hotspot in the field of landmark-based optical *** paper designs a fast crater landmark selection method,which not only considers the configuration observability of crater subsets but also focuses on the influence on navigation performance arising from the measurement uncertainty and the matching confidence of craters,which is different from other landmark selection *** factor of measurement uncertainty,which is anisotropic,correlated and nonidentically distributed,is quantified and integrated into selection based on crater pairing detection and localization error *** addition,the concept of the crater matching confidence factor is introduced,which reflects the possibility of 2D projection measurements corresponding to 3D *** with the configuration observability factor,the crater landmark selection indicator is ***,the effectiveness of the proposed method is verified by Monte Carlo simulations.

关键词： Crater-based optical navigation Crater landmark selection Crater matching Measurement uncertainty Planetary landing

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Joint Label-Specific Features and Correlation Information for Multi-Label Learning

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Journal of Computer Science & Technology 2020年第2期35卷 247-258页

作者： xiu-yi Jia Sai-Sai Zhu Wei-Wei Li School of Computer Science and Engineering Nanjing University of Science and TechnologyNanjing 210094China College of Astronautics Nanjing University of Aeronautics and AstronauticsNanjing 210016China

Multi-label learning deals with the problem where each instance is associated with a set of class *** multilabel learning,different labels may have their own inherent characteristics for distinguishing each other,and the correlation information has shown promising strength in improving multi-label *** this study,we propose a novel multilabel learning method by simultaneously taking into account both the learning of label-specific features and the correlation information during the learning ***,we learn a sparse weight parameter vector for each label based on the linear regression model,and the label-specific features can be extracted according to the corresponding weight ***,we constrain label correlations directly on the output of labels,not on the corresponding parameter vectors which conflicts with the label-specific feature ***,for any two related labels,their corresponding models should have similar outputs rather than similar parameter ***,we also exploit the sample correlations through sparse *** experimental results on 12 benchmark datasets show that the proposed method performs better than the existing *** proposed method ranks in the 1st place at 66.7%case and achieves optimal average rank in terms of all evaluation measures.

关键词： multi-label learning label-specific feature sparse reconstruction label correlation sample correlation

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Inner Structure of Statistical Gauge Potential in Chern-Simons-Ginzburg-Landau Theory

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Communications in Theoretical Physics 2005年第3X期44卷 559-562页

作者： DUAN yi-Shi ZHANG xiu-Ming Institute of Theoretical Physics Lanzhou University Lanzhou 730000 China

Based on the decomposition theory of the U（1） gauge potential, the inner structure of the statistical gauge potential in the Chern-Simons-Ginzburg-Landau （CSGL） theory is studied. We give a new creation mechanism of the statistical gauge potential, Furthermore, making use of the b-mapping topological current theory, we obtain the precise topological expression of the statistical magnetic field, which takes the topological information of the vortices.

关键词： gauge potential decomposition theory topological quantum mechanics

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Strict Feasibility of Variational Inequalities in Reflexive Banach Spaces

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Acta Mathematica Sinica,English Series 2007年第3期23卷 563-570页

作者： yi Ran HE xiu Zhen MAO Mi ZHOU Department of Mathematics Sichuan Normal University Chengdu 610068 P. R. China

Strict feasibility is proved to be an equivalent characterization of （dual） variational inequalities having a nonempty bounded solution set, provided the mappings involved are stably properly quasimonotone. This generalizes an earlier result from finite-dimensional Euclidean spaces to infinitedimensional reflexive Banach spaces. Moreover, the monotonicity-type assumptions are also mildly relaxed.

关键词： variational inequalities well-positioned sets barrier cone strict feasibility stably properly quasimonotone

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Comparison of Pb,Cd Adsorption to Surface Coatings Developed in Natural Waters with that in Plant Effluents

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Chemical Research in Chinese Universities 2003年第4期19卷 417-421页

作者： DONG De-ming LI Yu HUA xiu-yi ZHANG Jing-jing College of Environment and Resources Jilin UniversityChangchun 130023P.R.China

The comparative studies of Pb and Cd adsorption to the surface coatings(Fe, Mn, Al oxides, organic materials, and associated minerals), which were developed on glass slides in five natural and two technical waters(plant effluents), were carried out under controlled laboratory conditions(mineral salts solution with defined speciation, ionic strength 0 05 mol/L, 25 ℃ and pH 6 0). The classical Langmuir adsorption isotherm was applied to estimating the equilibrium coefficients of Pb and Cd adsorption to the surface coatings. The results show that the maximum adsorption of Pb and Cd to the surface coatings mentioned above varied widely. There was a systemic increase in the maximum adsorption of Pb and Cd to the surface coatings with increasing the contents of Mn and Fe oxides in the surface coatings in significant correlation, respectively, not only highlighting the relative importance of the metal oxide fraction for Pb and Cd adsorption to the surface coatings developed in natural and technical water samples, but also implying the same adsorption mechanisms of Pb and Cd to the surface coatings developed both in natural and technical water samples.

关键词： Natural waters Plant effluents Surface coatings Pb Cd

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Fatigue Property of Low Cost and High Strength Wheel Steel for Commercial Vehicle

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Journal of Iron and Steel Research International 2009年第4期16卷 44-48,77页

作者： WANG Ning LI yi DU Lin-xiu WU Di LIU Xiang-hua The State Key Laboratory of Rolling and Automation Northeastern University Shenyang 110004 Liaoning China

The fatigue properties of the newly developed wheel steel used for commercial vehicles were studied using push-pull axial loading fatigue tests with stress ratio R=-1. Q235B steel, which is conventionally applied to commercial vehicle wheels, was also analyzed for comparison. Although the chemical composition and microstructure （ferrite and pearlite） of newly developed wheel steel were similar to those of Q235B, the 107 cycles fatigue limit of the new wheel steel was 260 MPa, which is 24% higher than that of Q235B （210 MPa）. The improvement of the fatigue strength of the new wheel steel can be attributed to grain refinement. In order to investigate the effect of the decrease in thickness of the wheel steel on the fatigue property of the wheel, dynamic cornering fatigue tests were conducted on full scale wheels with the model of 8.25 × 22.5. The results indicated that the newly developed wheel steel had outstanding fatigue life even if the mass loss was 10% in comparison with Q235B.

关键词： high strength wheel steel fatigue strength grain refinement dynamic cornering fatigue test

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The applicability and underlying factors of frequency-dependent amplitude-versus-offset(AVO)inversion

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Petroleum Science 2023年第4期20卷 2075-2091页

作者： Fang Ouyang Xin-Ze Liu BinWang Zi-Duo Hu Jian-Guo Zhao xiu-yi Yan Yu Zhang yi-He Qing State Key Laboratory of Petroleum Resource and Prospecting China University of Petroleum(Beijing)Beijing102249China Institute of Earthquake Forecasting China Earthquake AdministrationBeijing100036China Yumen Oil Field Branch of CNPC Exploration and Development Research Institute JiuquanGansu735000China Northwest Branch of PetroChina Research Institute of Petroleum Exploration and Development LanzhouGansu730020China Unconventional Petroleum Research Institute China University of Petroleum(Beijing)Beijing102249China College of Chemical Engineering and Environment China University of Petroleum(Beijing)Beijing102249China

Recently,the great potential of seismic dispersion attributes in oil and gas exploration has attracted extensive *** frequency-dependent amplitude versus offset(FAVO)technology,with dispersion gradient as a hydrocarbon indicator,has developed *** on the classical AVO theory,the technology works on the assumption that elastic parameters are frequency-dependent,and implements FAVO inversion using spectral decomposition methods,so that it can take dispersive effects into account and effectively overcome the limitations of the classical ***,the factors that affect FAVO are *** this end,we construct a unified equation for FAVO inversion by combining several Zoeppritz *** study and compare two strategies respectively with(strategy 1)and without(strategy 2)velocity as inversion input *** theoretical models,we investigate the influence of various factors,such as the Zoeppritz approximation used,P-and S-wave velocity dispersion,inversion input data,the strong reflection caused by non-reservoir interfaces,and the noise level of the seismic *** results show that FAVO inversion based on different Zoeppritz approximations gives similar *** addition,the inversion results of strategy 2 are generally equivalent to that of strategy 1,which means that strategy 2 can be used to obtain dispersion attributes even if the velocity is not *** also found that the existence of non-reservoir strong reflection interface may cause significant false ***,logging,geological,and other relevant data should be fully used to prevent this undesirable *** the P-and S-wave related dispersion obtained from FAVO can be used as good indicators of a hydrocarbon reservoir,but the P-wave dispersion is more *** fact,due to the mutual coupling of P-and S-wave dispersion terms,the P-wave dispersion gradient inverted from PP reflection seismic data has a stronger hydrocarbon detection ability than

关键词： Zoeppritz approximation Dispersion gradient Frequency-dependent AVO inversion Reservoir prediction Fluid identification

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Ca_(0.5)Sr_(0.5)TiO_(3)-Modified KNN-Based Lead-Free Piezoceramics with a Wide Temperature Usage Span

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Chinese Physics Letters 2011年第6期28卷 280-282页

作者： DU Juan WANG Jin-Feng ZANG Guo-Zhong yi xiu-Jie College of Materials Science and Engineering Liaocheng UniversityLiaocheng 252059 School of Physics Shandong UniversityJi'nan 250100

The strong temperature dependence of dielectric and piezoelectric properties is a big'bottleneck'for practical applications of KNN-based *** order to resolve this problem,Ca_(0.5)Sr_(0.5)TiO_(3)(CST)is doped into(Na_(0.53)K_(0.4)0_(7)Li_(0.063))Nb0.937Sb0.063O3(NKLNS)*** thermal stability of s11E and k31 in the temperature range from−50℃to 200℃for ceramics with 1.0 and 1.5 mol%CST is raised in comparison with ceramics without *** with 1.5 mol%CST exhibit high piezoelectric properties(d33=202 pC/N,kp=44%)and low dielectric loss(2%)at room *** excellent piezoelectric properties,which are comparable to conventional PZT ceramics,indicate that these ceramics are promising candidates for lead-free piezoelectric applications.

关键词： ceramics temperature piezoelectric

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Crystal Structure and Properties of [PrCl(H_2O)_3(L)(HL)]_nnCl(HL=3-Hydroxy-2-methylquinoline-4-carboxylic acid) with One-dimensional Chains

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Chinese Journal of Structural Chemistry 2019年第2期38卷 325-330,169页

作者： yi xiu-Guang LIU Yan-Zhu FANG Xiao-Niu ZHOU Xiao-ying LI Yong-xiu School of Materials Science and Engineering & School of Chemistry Nanchang University Institute of Applied Chemistry Jiangxi Province Key Laboratory of Coordination ChemistrySchool of Chemistry and Chemical Engineering Jinggangshan University School of New Energy Science and Engineering Xinyu University

A novel praseodymium complex [PrCl(H_2O)_3(L)(HL)]_nnCl(1, HL = 3-hydroxy-2-methylquinoline-4-carboxylic acid) has been synthesized through hydrothermal reactions and characterized by single-crystal X-ray diffraction. Complex 1 crystallizes in P2_1 space group of the monoclinic system, with a = 7.3146(2), b = 9.3963(3), c = 17.4872(5) ?, β = 96.818(3)°, V = 1193.40(6) ?~3, C_(22)H_(23)Cl_2N_2O_9Pr, M_r = 671.23, Z = 2, D_c = 1.868 g/cm^3, μ(MoKα) = 2.322 mm^(-1) and F(000) = 668. The praseodymium ion is surrounded by seven oxygen atoms and one chlorine atom to yield a slightly distorted square antiprism. Complex 1 is characterized by a one-dimensional chain-like structure. A two-dimensional supramolecular layer is formed via hydrogen-bonding interactions. Solid-state photoluminescence spectrum reveals that it shows red emission. The emission bands are ascribed to the characteristic emission of the 4 f electron transitions of ~3P_0 → ~3H_J(J = 5 and 6) and ~3P_0 → ~3F_4 of Pr^(3+) ions. Solid-state UV/Vis diffuse reflectance spectroscopy exhibits that it has an optical band gap of 2.75 eV.

关键词： photoluminescence praseodymium semiconductor supermolecule lanthanide

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Preparation,Structure,Fluorescence,Semiconductor Properties and TDDFT Calculation of a Mononuclear Zinc Complex with Mixed Ligands

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Chinese Journal of Structural Chemistry 2020年第3期39卷 551-558,379页

作者： LI Jia SHI Lian-Shui yi xiu-Guang FANG Xiao-Niu GUO Ting LI Yong-xiu School of Chemistry and Chemical Engineering Jinggangshan UniversityJi'an 343009China School of Chemistry Nanchang UniversityNanchang 330000China School of Stomatology Nanchang UniversityThe Key Laboratory of Oral BiomedicineNanchang 330000China

A novel zinc complex[ZnL(bipy)(H2O)]×H2O with mixed ligands of 3-hydroxy-2-methylquinoline-4-carboxylic acid(HL)and bipy(bipy=2,2'-bipyridine)was synthesized by solvothermal reaction and its crystal structure was determined by single-crystal X-ray diffraction *** title compound crystallizes in the orthorhombic system of Pbca space group,and exists as an isolated mononuclear *** intermolecular hydrogen bonds and strongπ…πstacking interactions form a three-dimensional(3-D)supramolecular ***-state photoluminescence spectrum reveals that it shows an emission in the blue region of the light ***-dependent density functional theory(TDDFT)calculations reveal that this emission can be attributed to ligand-to-ligand charge transfer(LLCT).Solid-state diffuse reflectance data show that there is a narrow optical band gap of 1.83 eV.

关键词： crystal structure photoluminescence semiconductor TDDFT LLCT

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