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On Compact Graphs

Acta Mathematica Sinica,English Series 2005年第5期21卷 1087-1092页

作者： Ping WANG jiong Sheng li State Key Laboratory of Information Security Graduate School Chinese Academy of Sciences Beijing 100039 P. R. China Department of Mathematics University of Science and Technology of ChinaHefei 230026 P. R. China

Let G be a finite simple graph with adjacency matrix A, and let P（A） be the convex closure of the set of all permutation matrices commuting with A. G is said to be compact if every doubly stochastic matrix which commutes with A is in P（A）. In this paper, we characterize 3-regular compact graphs and prove that if G is a connected regular compact graph, G - v is also compact, and give a family of almost regular compact connected graphs.

关键词： Double stochastic matrix Compact graph Automorphism group

The Threshold for the Erdos,Jacobson and Lehel Conjecture to Be True

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Acta Mathematica Sinica,English Series 2006年第4期22卷 1133-1138页

作者： jiong Sheng li Jian Hua YIN Department of Mathematics University of Science and Technology of China Hefei 230026 P. R. China Department of Applied Mathematics College of Information Science and Technology Hainan University Haikou 570228 P. R. China

Let σ（k, n） be the smallest even integer such that each n-term positive graphic sequence with term sum at least σ（k, n） can be realized by a graph containing a clique of k ＋ 1 vertices. Erdos et al. （Graph Theory, 1991, 439-449） conjectured that σ（k, n） = （k - 1）（2n- k）＋ 2. li et al. （Science in China, 1998, 510-520） proved that the conjecture is true for k 〉 5 and n ≥ （k2）＋ 3, and raised the problem of determining the smallest integer N（k） such that the conjecture holds for n ≥ N（k）. They also determined the values of N（k） for 2 ≤ k ≤ 7, and proved that [5k-1/2] ≤ N（k） ≤ （k2）＋ 3 for k ≥ 8. In this paper, we determine the exact values of σ（k, n） for n ≥ 2k＋3 and k ≥ 6. Therefore, the problem of determining σ（k, n） is completely solved. In addition, we prove as a corollary that N（k） -= [5k-1/2] for k ≥6.

关键词： Graph Degree sequence Potentially Kk+1-graphic sequence

Prescribed performance neural control to guarantee tracking quality for near space kinetic kill vehicle

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Journal of Systems Engineering and Electronics 2019年第3期30卷 573-586页

作者： ZHANG Tao li jiong li Weimin WANG Huaji LEI Humin Air and Missile Defense College Air Force Engineering University

A prescribed performance neural controller to guarantee tracking quality is addressed for the near space kinetic kill vehicle (NSKKV) to meet the state constraints caused by side window detection. Different from the traditional prescribed performance control in which the shape of the performance function is constant, this paper exploits new performance functions which can change the shape of their function according to different symbols of initial errors and can ensure the error convergence with a small overshoot. The neural backstepping control and the minimal learning parameters (MLP) technology are employed for exploring a prescribed performance controller (PPC) that provides robust tracking attitude reference trajectories. The highlight is that the transient performance of tracking errors is satisfactory and the computational load of neural approximation is low. The pseudo rate (PSR) modulator is used to shape the continuous control command to pulse or on-off signals to meet the requirements of the thruster. Numerical simulations show that the proposed method can achieve state constraints, pseudo-linear operation and high accuracy.

关键词： prescribed performance control near space kinetic kill vehicle (NSKKV) neural approximation minimal learning parameter (MLP) pseudo rate (PSR) modulator

A Variation of a Conjecture Due to Erds and Sós

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Acta Mathematica Sinica,English Series 2009年第5期25卷 795-802页

作者： Jian Hua YIN jiong Sheng li Department of Mathematics School of Information Science and Technology Hainan University Haikou 570228 P.R. China Department of Mathematics University of Science and Technology of China Hefei 230026 P.R. China

Erdoes and Soes conjectured in 1963 that every graph G on n vertices with edge number e（G）〉 1/2（k - 1）n contains every tree T with k edges as a subgraph. In this paper, we consider a variation of the above conjecture, that is, for n 〉 9/ 2k^2 ＋ 37/2＋ 14 and every graph G on n vertices with e（G）〉 1/2 （k- 1）n, we prove that there exists a graph G＇ on n vertices having the same degree sequence as G and containing every tree T with k edges as a subgraph.

关键词： graph degree sequence Erdoes-Soes conjecture

Tween-modified suspension array for sensitive biomolecular detection

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Chinese Science Bulletin 2013年第21期58卷 2628-2633页

作者： ZHAO Zhuan li Zong li jiong Division of Nano-biomedicine Suzhou Institute of Nano-tech and Nano-bionics Chinese Academy of Sciences Technical Institute of Physics and Chemistry Chinese Academy of Sciences Graduate University of Chinese Academy of Sciences Institute of Semiconductors Chinese Academy of Sciences

Suspension arrays are attracting increasing interest for detecting and quantifying proteins, nucleic acids and other biomolecules. Among various suspension arrays, sillica-based suspension arrays which benefit from low fluorescence background and material stability have been widely used. Sillica-based suspension arrays are often manufactured with the popular aldehyde-aminosilane chemistry for the attachment of a variety of biomolecules. One drawback of this immobilization strategies is the relatively high array particles lost efficiency when washed by centrifugation. Due to this shortcoming, it is low reproductivity and limited in multiplex assay. Herein we report a novel method to fabricate Tween-coated suspension sillica particles, which could achieve good- reproductivity and the low limit of detection. Tween surfactants, each containing hydrophilic ethylene glycol head groups and a hydrophobic alkyl tail, prevent silica particles from being adsorbed onto the centrifuge tube wall and make beads resuspended well. Also, Tween with low fluorescence background could reduce non-specific protein adsorption. Also Tween surfactants are economic and facile agent. In this study, we demonstrate the preparation of the protein array to substantiate the applicability of our approach. Under the optimized experiment conditions, the limit of detection of our Tween-modified particles is as low as 50 pg/mL, which is sufficiently low for the current methods. We believe that the proposed method could provide a perspective on the improvement of self-encoded silica particle arrays.

关键词：蛋白质阵列分子检测生物分子再悬浮吐温改性二氧化硅粒子特异性蛋白质

Quick-scanning X-ray absorption fine structure beamline at SSRF

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Nuclear Science and Techniques 2024年第6期35卷 1-13页

作者： Yu Chen Qian Gao Zheng Jiang jiong li Shuo Zhang Shanghai Synchrotron Radiation Facility Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201204China National Synchrotron Radiation Laboratory University of Science and Technology of ChinaHefei 230029China

The layout and characteristics of the hard X-ray spectroscopy beamline(BL11B)at the Shanghai synchrotron radiation facility are described ***11B is a bending-magnet beamline dedicated to conventional and millisecond-scale quick-scanning X-ray absorption fine *** is equipped with a cylindrical collimating mirror,a double-crystal monochromator comprising Si(111)and Si(311),a channel-cut quick-scanning Si(111)monochromator,a toroidal focusing mirror,and a high harmonics rejection *** can provide 5-30 keV of X-rays with a photon flux of~5×10^(11)photons/s and an energy resolution of~1.31×10^(-4)at 10 *** performance of the beamline can satisfy the demands of users in the fields of catalysis,materials,and environmental *** paper presents an overview of the beamline design and a detailed description of its performance and capabilities.

关键词： Bending magnet beamline X-ray absorption fine structure Quick-scanning XAFS In situ Synchrotron radiation

Mechanical and tribological properties of graphene nanoplatelets-reinforced titanium composites fabricated by powder metallurgy

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Journal of Iron and Steel Research International 2020年第11期27卷 1357-1362页

作者： Zhen Cao jiong-li li Hai-ping Zhang Wen-bo li Xu-dong Wang AECC Beijing Institute of Aeronautical Materials Beijing 100095China Beijing Institute of Graphene Technology Beijing 100094China Beijing Engineering Research Centre of Graphene Application Beijing 100095China

Titanium matrix composite reinforced by graphene nanoplatelets(GNPs)was fabricated via powder metallurgy *** isostatic pressing and hot extrusion were used to consolidate the mixed powder of GNPs and TC4 titanium(Ti)*** microstructures,mechanical properties and sliding wear performance of Ti/GNPs composite had been researched to evaluate the rein forcing effect of GNPs on tita nium *** observation indicates that GNPs could restrain grai n growth slightly in titanium *** matrix and graphene exhibit a clean and firm interface formed by means of metallurgical bonding on atomic *** with the monolithic titanium alloy,the composite with 1.2 vol.%GNPs exhibits significantly improved elastic modulus and *** sliding wear test shows that there is an obvious enhancement in the tribological performance of Ti/GNPs composite with 1.2 vol.%*** results of this work indicate that GNP is an efficient reinforcenient material in titanium *** strengthening mechanism including precipitates strengthening,load transfer and grain refinement mechanism of GNPs in titanium matrix was discussed.A modified shear-lag model was used to analyze the reinforcement contribution of the stress transfer *** calculation shows that the stress load mechanism constitutes the main strengthening mechanism in Ti/GNPs composite.

关键词： Titanium matrix composite Graphene Mechanical testing Tribological property Powder metallurgy

Concentrations of heavy metals and polycyclic aromatic hydrocarbons in needles of Masson pine (Pinus massoniana L.) growing nearby different industrial sources

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Journal of Environmental Sciences 2010年第7期22卷 1006-1013页

作者： Fangfang Sun Dazhi Wen Yuanwen Kuang jiong li Jianli li Weidong Zuo South China Botanical Garden Chinese Academy of Sciences Guangzhou 510650 China Graduate University of Chinese Academy of Sciences Beijing 100049 China Pearl River Delta Research Center of Environmental Pollution and Control Chinese Academy of Sciences Guangzhou 510640 China Agriculture and Forestry Technology Extension Centre of Nanhai District Guangdong 528222 China

Emissions from industrial activities pose a serious threat to human health and impose the need for monitoring both inorganic and organic pollutants in industrial areas. We selected Masson pine （Pinus massoniana L.） as potential biomonitor and collected the current （C） and previous year （C＋ 1） needles from three industrial sites dominated by petrochemical, ceramics manufacturing, and iron and steel smelting plants and one remote site to determine heavy metals （Cu, Cd, Pb, Zn, Cr, Ni and Co） and polycyclic aromatic hydrocarbons （PAHs） in unwashed and water-washed needles. Both unwashed and washed C＋ 1 needles showed generally higher concentrations of heavy metals and PAHs than C needles, although the washed needles more clearly spotlighted the accumulation effect of PAHs over exposure time. Water-washing resulted in a significant decrease in needle PAH concentrations with more significant effects shown in C needles. By contrast, needle heavy metal concentrations were much less affected by washing. Although heavy metals and PAHs might differ in adsorption and uptake strategies, their higher concentrations in the needles at the industrial sites indicated conspicuous contamination due to industrial emissions there. The PAH distribution patterns in pine needles accorded with the real types of energy consumption in the study sites and were efficiently used for pinpointing local pollutant sources.

关键词： biomonitoring needle age polycyclic aromatic hydrocarbons water-washing

Microwave-assisted synthesis of diaryl or aryl-alkyl sulfones without catalyst

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Chinese Chemical Letters 2009年第1期20卷 17-20页

作者： jiong Zou Feng li Feng Gang Tao Department of Chemistry Fudan University Shanghai 200433 China

The microwave-assisted coupling reaction of electrondeficient aryl halides with sulfinic acid salts through SNAr-based addition reactions within 5-30 min. No catalysts were required under our conditions.

关键词： Microwave Sulfone SNAr-based addition reaction