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Second-order consensus in networks of dynamic agents with communication time-delays

Journal of Systems Engineering and Electronics 2010年第1期21卷 88-94页

作者： Bo Yang1,2. Huajing Fang3, and Hua Wang4.1. School of Navigation, wuhan university of Technology, wuhan 4.0063, P. R. {4. 2. wuhan Second Ship Design and Research Institute, wuhan 4.0064. P. R. {4. 3. Department of Control Science and Engineering, Huazhong university of Science and Technology, wuhan 4.0074. P. R. {4. 4. Department of Aerospace and Mechanical Engineering, Boston university, Boston MA02.15, USA School of Navigation Wuhan University of Technology Wuhan 430063 P. R. China wuhan Second Ship Design and Research Institute Wuhan 430064 P. R. China Department of Control Science and Engineering Huazhong University of Science and Technology Wuhan 430074 P. R. China Department of Aerospace and Mechanical Engineering Boston University Boston MA02215 USA

This paper proposes second-order consensus protocols with time-delays and gives the measure of the robustness of the protocols to the time-delay existing in the network of agents with second-order dynamics. By employing a frequency domain method, it is proven that the information states and their time derivatives of all the agents in the network achieve consensus asymptotically, respectively, for appropriate communication timedelay if the topology of weighted network is connected. Particularly, a tight upper bound on the communication time-delay that can be tolerated in the dynamic network is found. The consensus protocols are distributed in the sense that each agent only needs information from its neighboring agents, which reduces the complexity of connections between neighboring agents significantly. Numerical simulation results are provided to demonstrate the effectiveness and the sharpness of the theoretical results for second-order consensus in networks in the presence of communication time-delays.

关键词： second-order consensus protocols dynamic networks algebraic graph theory frequency domain analysis com-munication constraints.

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Analysis and application of automatic deformation monitoring data for buildings and structures of mining area

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中国有色金属学会会刊：英文版 2011年第S3期21卷 516-522页

作者： XIAO Jie1, 2. 3, ZHANG Jin4.1. Institute of Geodesy and Geophysics, Chinese Academy of Sciences, wuhan 4.0077, china 2. Key Laboratory of Dynamic Geodesy, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, wuhan 4.0077, china 3. Graduate School of Chinese Academy of Sciences, Beijing 10004., china 4. Department of Surveying and Mapping, Taiyuan university of Technology, Taiyuan 03002., china Institute of Geodesy and Geophysics Chinese Academy of Sciences Wuhan 430077 China Key Laboratory of Dynamic Geodesy Institute of Geodesy and Geophysics Chinese Academy of Sciences Wuhan 430077 China Graduate School of Chinese Academy of Sciences Beijing 100049 China Department of Surveying and Mapping Taiyuan University of Technology Taiyuan 030024 China

The buildings and structures of mines were monitored automatically using modern surveying technology. Through the analysis of the monitoring data, the deformation characteristics were found out from three aspects containing points, lines and regions, which play an important role in understanding the stable state of buildings and structures. The stability and deformation of monitoring points were analysed, and time-series data of monitoring points were denoised with wavelet analysis and Kalman filtering, and exponent function and periodic function were used to get the ideal deformation trend model of monitoring points. Through calculating the monitoring data obtained, analyzing the deformation trend, and cognizing the deformation regularity, it can better service mine safety production and decision-making.

关键词： wavelet analysis Kalman filtering deformation monitoring data analysis mine

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HCWCI/Carbon Steel Bimetal Liner by Liquid-Liquid Compound Lost Foam Casting

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Journal of Iron and Steel Research International 2012年第10期19卷 13-19页

作者： XIAO Xiao-feng1,2. YE Sheng-ping2. YIN Wei-xin3, XUE Qiong4.(1. School of Mechanical Engineering and Automation, wuhan Textile university, wuhan 4.0073, Hubei, china 2. State Key Laboratory of Material Processing and Die and Mould Technology, Huazhong university of Science and Technology, wuhan 4.0074. Hubei, china 3. wuhan Zhike Abrasive-Resistant Material Science and Technology Development Co Ltd, wuhan 4.0073, Hubei, china 4. College of Science, wuhan university of Technology, wuhan 4.0079, Hubei, china) School of Mechanical Engineering and Automation Wuhan Textile University Wuhan Hubei China State Key Laboratory of Material Processing and Die and Mould Technology Huazhong University of Science and Technology Wuhan Hubei China wuhan Zhike Abrasive-Resistant Material Science and Technology Development Co Ltd Wuhan Hubei China College of Science Wuhan University of Technology Wuhan Hubei China

Impact, friction and corrosion from the grinding balls and the grinding medium during the mineral processing result in liner breakage. Liner, made from Hadfield steel or alloyed steel, could not have served in wet grinding environment for more than ten months. Composite liner, made from HCWCI (high Cr white cast iron) and carbon steel, has been developed successfully with liquid-liquid composing process based on LFC (lost foam casting). The microstructure of composite was analyzed with optical microscope, SEM (scanning electron microscope)/EDX energy-dispersive X-ray and XRD (X-ray diffraction). According to micrograph, the combination region of two metals was staggered like dogtooth, no mixtures occurred between two liquid metals, and its interface presented excellent metallurgical bonding state. The results of mechanical property test show that, the hardness of HRC, the fracture toughness, and the bending strength are more than 61, 16.5 J/cm2.and 1 600 MPa, respectively. Comparison between liners made from bimetal composite and alloyed steel has also been investigated in industrial hematite ball mill. The results of eight months test in wet grinding environment prove that the service life of bimetal composite liner is three times as long as that of one made from alloyed steel.

关键词： composite liner bimetal liquid-liquid compound composite interface lost foam casting high Cr white cast iron

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The crustal structure under Sanjiang and its dynamic implications:Revealed by seismic reflection/refraction profile between Zhefang and Binchuan,Yunnan

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Science china Earth Sciences 2005年第9期48卷 1329-1336页

作者： ZHANG Zhongjie1, BAI Zhiming1, WANG Chunyong2. TENG Jiwen1, Lü Qingtian3, LI Jiliang1, LIU Yifeng1 & LIU Zhenkuan4.1. Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 10002., china 2. Institute of Geophysics, china Seismological Bureau, Beijing 100085, china 3. Institute of Deposition Resource, Chinese Academy of geosciences, Beijing 100037, china 4. School of Exploration and Information, china university of geosciences, Beijing 100083, china Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China Institute of Geophysics China Seismological Bureau Beijing China Institute of Deposition Resource Chinese Academy of Geosciences Beijing China School of Exploration and Information China University of Geosciences Beijing China

The fault belts in Sanjiang mainly include Jinshajiang-Honghe fault, Lancangjiang fault and Nujiang fault (called Sanjiang faults) in western Yunnan Province, china. By interpreting the wide-angle seismic reflection/refraction profile between Zhefang and Binchuan, which crosses Tengchong and Baoshan blocks in Dianxi (western Yunnan) tectonic zone, we recon- struct the crustal structure with seismic traveltime tomography for crustal P-wave velocity and the seismic scattering image for crustal seismic reflection structure. In this paper, we firstly present the crustal structure images of P-wave velocity and seismic reflection under the wide-angle seismic profile. These results demonstrate that, the crustal velocity structure and seismic reflec- tion structure along the profile can be divided into 3 segments, and there is an obvious difference of crustal structure among the eastern, the western and the middle segment. Generally, crustal P-wave velocities in the Baoshan segment are 0.1―0.2.km/s slower and seismic reflection am- plitudes from Moho discontinuity are stronger than the other 2.segments. In the studied area, crustal thickness is about 4. km, and shows the thickening tendency from west to east along the profile. Additionally, it can be seen that there is one strong-amplitude seismic reflection event as bright points at the depths of 8―10 km, along the segment of 80―115 km of the profile (south- ward of Tengchong); and seismic reflection wave-field from Moho discontinuity varies obviously along the lateral direction. Finally, we make some discussions on the crustal thickening pattern in the Sanjiang fault belt, structural environment of earthquake development and the contact rela- tionship between the Tengchong block, Banshan block and Luxi trough.

关键词： Sanjiang area wide-angle seismic profile crustal structure.

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Progress and review of the studies on the end-Triassic mass extinction event

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Science china Earth Sciences 2005年第12期48卷 2049-2060页

作者： DENG Shenghui1,2. LU Yuanzheng1,2.3 & XU Daoyi4.1. Research Institute of Petroleum Exploration and Development, Beijing 100083, china 2. Key Laboratory of Oil and Gas Reservoir of Petrochina, Beijing 100083, china 3. china university of geosciences, Beijing 100083, china 4. Institute of Geology, china Earthquake Administration, Beijing 10002., china Research Institute of Petroleum Exploration and Development Beijing China Key Laboratory of Oil and Gas Reservoir of Petrochina Beijing China china university of {2. Beijing China Institute of Geology China Earthquake Administration Beijing China

The mass extinction at the end-Triassic is one of the five biggest in the Phanerozoic. However,it is the least well understood among these five events, and only till last decade it became a great academic interesting subject to geologists. The evidences for this event come obviously from bivalves, brachiopods, ammonites, corals, radiolaria, ostracods and foraminifera of marine habitats, and plants and tetrapods of terrestrial realm. By contrast, for some of other groups, such as marine gastropods and marine vertebrates, no mass extinction has been recog-nized yet. The extinction event is strongly marked at specific level but shown a complicated situa-tion at generic and family levels. Dramatic changing of the environment, such as the temperature raise due to the greenhouse effect, the marine anoxic habitats caused by a sudden transgression after the regression at the end of Triassic, has been claimed to be the main cause of the extinction. Many hypotheses have been suggested to demonstrate the mechanisms of the environment changing, among which two popular ones are the bolide impact and volcanic eruption. The Triassic-Jurassic (Tr-J) boundary mass extinction event is still poorly understood because no enough data have been obtained from the Tr-J boundary successional sections of both marine and terrestrial sediments, and most of these studies were regionally restricted. The basic aspects of the event and its associated environmental conditions remain poorly characterized and the causal mechanism or mechanisms are equivocal. Some authors even doubt its occurrence. china has many successionally developed terrestrial and marine Tr-J sections. Detailed studies of these sections may be important and significant for well understanding of the event.

关键词： progress, review, end-Triassic, mass extinction, mechanism, Tr-J boundary.

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Sorption of Eu^(3+) onto nano-size silica-water interfaces

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Science china Earth Sciences 2005年第11期48卷 1942-1948页

作者： HU Ping1,2. YIN Xiulan3 , ZHAO Linghu1 & LI Dien4.1. Department of Earth Sciences, china university of geosciences, wuhan {2. {4. 2. Northeastern Illinois university, Chicago, IL 6062., USA 3. {4. Institute of Geo-Environmental Monitoring, Beijing 100081, {4. 4. Division of Chemistry, Los Alamos National Laboratory, Los Alamos, NM 8754., USA Department of Earth Sciences China University of Geosciences Wuhan China Northeastern Illinois university Chicago IL USA china Institute of Geo-Environmental Monitoring Beijing China Division of Chemistry Los Alamos National Laboratory Los Alamos NM USA

The sorption of Eu species onto nano-size silica-water interfaces is investigated at pH range of 1―8.5 and the initial Eu concentrations (CEu) of 2.× 10?5, 2.× 10?4.and 2.× 10?3 M using fluorescence spectroscopy. The sorption rate of Eu is initially low, but significantly in-creases at pH > 4. For the initial CEu of 2.× 10?5, 2.× 10?4.and 2.× 10?3 M, the dissolved Eu spe-cies are completely sorbed onto silica-water interfaces at pH = 4.75, ~5.8 and 6.6, respectively, with the respective sorption densities of ~1.58 × 10?8, 1.58 × 10?7 and 1.58 × 10?6 mol/m2. The sorbed Eu species at pH 2. to ~6 at pH = 6. At pH = 6 – 8, Eu(OH)2., Eu(CO3)+ and Eu(CO3)2. form in the solutions, and Eu(CO3)+ is dominant at pH = ~7.5. These ions may be sorbed onto silica-water interfaces as inner-sphere bidentate complexes or multi-nuclear pre-cipitates.

关键词： surface sorption, Eu3+ species, nano-size silica, fluorescence spectroscopy, immobilization of toxic metals

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Indian Ocean-MORB-type isotopic signature of Yushigou ophiolite in North Qilian Mountains and its implications

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Science china Earth Sciences 2006年第6期49卷 561-572页

作者： HOU Qingye1,2. ZHAO Zhidan1,2. ZHANG Hongfei3, ZHANG Benren3 & CHEN Yuelong2.1. State Key Laboratory of Geological Processes and Mineral Resources, china university of geosciences, Beijing 100083, {4. 2. School of Earth Science and Mineral Resources, china university of geosciences, Beijing 100083, {4. 3. Faculty of Earth Sciences, china university of geosciences, wuhan 4.0074. {4. State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Beijing China School of Earth Science and Mineral Resources China University of Geosciences Beijing China Faculty of Earth Sciences China University of Geosciences Wuhan China

In order to explore the disputed issue concerning the tectonic affinity ofthe ancient ocean mantle of North Qilian Mountains (NQM), geochemical and Sr, Nd, Pb isotopiccompositions of pillow basalts of the Yushigou Ophiolite (YSGO) suite from NQM have been analyzedsystematically. The pillow basalts exhibit tholeiitic characteristics, with flatchondrite-normalized REE patterns ((La/Yb)_N = 0.98—1.2.). They display no Nb, Ta, Zr, Hf negativeanomalies, and show MORB features in 2.b-Zr/4.Y and Ti/100-Zr-YX3 tectonic discrimination *** results indicate that the Yushigou ophiolite is most likely to be formed in a mid-ocean ridgeor mature back-arc basin. Their isotopic data show a relatively broad and enriched ^(87)Sr/^(86)Sr(0.70509 — 0.70700), restricted ^(14.)Nd/^(14.)Nd (0.512.55-0.512.78). Pb isotopes are in the rangeof ^(2.6)Pb/^(2.4.Pb (18.054.2..562., ^(2.7)Pb/^(2.4.Pb (15.537-15.74.) and ^(2.8)Pb/^(2.4.Pb(38.068-38.530). These isotopic data imply that the basalts originated from the depleted mantle(DMM), with the involvement of enriched mantle components (mainly EMII). Geochemical comparisonsbetween the basalts in YSGO and the MORB-type basalts of ophiolite suites occurring in the knownancient Tethyan tectonic domain indicate that the ancient oceanic mantle represented by YSGO suiteforming in early Paleozoic in the North Qilian Moutains is very similar to the Tethyan mantle inboth trace elements and isotopic compositions. The North Qilian Mountains should be a part of theTethyan tectonic domain in early Paleozoic. This further implies that the Tethyan tectonic domaincan be deduced to early Paleozoic in the study area, which will be helpful to discussing thetectonic affinity and evolution of the North Qilian Mountains.

关键词： geochemistry, Indian Ocean-MORB-type isotopic signatures, Tethyan tectonic domain, Yushigou ophiolite, North Qilian Mountains.

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Geochemistry of high-Mg andesites from the early Cretaceous Yixian Formation, western Liaoning: Implications for lower crustal delamination and Sr/Y variations

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Science china Earth Sciences 2006年第9期49卷 904-914页

作者： WANG Xiaorui1, GAO Shan1,2. LIU Xiaoming1, YUAN Honglin1, HU Zhaochu1, ZHANG Hong1,3 & WANG Xuance4.1. State Key Laboratory of Continental Dynamics, Department of Geology, Northwest university, Xi`an 710069, china 2. State Key Laboratory of Geological Processes and Mineral Resources,{2., wuhan 4.0074. china 3. Shenyang Institute of Geology and Mineral Resources, Shenyang 110032. china 4. Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 51064., china State Key Laboratory of Continental Dynamics Department of Geology Northwest University Xi’an China State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Wuhan China Shenyang Institute of Geology and Mineral Resources Shenyang China Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou China

85 volcanic rocks of the Yixian Formation from the Sihetun type section werecollected and analyzed for geochemical and isotopic compositions. Major element compositionsindicate that the Sihetun volcanic rocks are high magnesium andesites with some basalts occurring atthe bottom of section. The Sihetun high magnesium andesites (SiO_2.= 52.82.59.31 wt%, Al_2._3=14.15-16.35wt%) show many characteristics of adakites such as depletion in heavy rare-earth elements(HREE; Yb = 1.03-1.88 μg/g) and Y(12.2. μg/g) and high Sr (62.-132. μg/g) and Sr/Y(32.88), withhigh La_N/Yb_N ratio (10-2.). They share similar major and trace element characteristics to volcanicrocks from the Xinglonggou Formation except their lower Nd isotope ratios (^(14.)Nd/^(14.)Nd(130Ma) = 0.5118-0.5119, ε_(Nd) (130Ma) = -11.6-13.8, ^(87)Sr/^(86)Sr (130 Ma) = *** were interpreted in a way that eclogite that formed at the base of thickened Archean lowercrust of the North china craton foundered into the convecting mantle and subsequently melted andinteracted with peridotite. However, compared to the Xinglonggou volcanic rocks, the source of theSihetun magma contained more ancient continental crustal material in order to explain its evolved Ndisotopes. The age of the Sihetun Formation was 12. to 130 Ma, and this indicates that delaminationlasted to the early Cretaceous period. The Sr contents and Sr/Y ratios of the Sihetun high-Mgandesites show significant negative correlations with SiO_2.for samples with SiO_2.> 56%. Thesesuggest that the Sr and Sr/Y values were reduced due to fractional crystallization of ***, the effect of crystallization on volcanic Sr and Sr/Y ratio has to be taken intoaccount.

关键词： High-Mg andesite, Adakite, Yixian Formation, North china Craton, delamination.

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Gradient analysis of landscape spatial and temporal pattern changes in Beijing metropolitan area

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Science china(Technological Sciences) 2010年第S1期53卷 91-98页

作者： YANG YeTao1,ZHOU QiMing2.GONG JianYa3 & WANG YingYing4.1 Institute of Geophysics and Geomatics,china university of {2.,{4. 4.0074.china 2.Department of Geography,Hong Kong Baptist university,Hong Kong 3 State Key Laboratory of Information Engineering in Surveying,Mapping and Remote Sensing,{4. university,{4. 4.0074.china 4.Hubei Provincial Bureau of Meteorology,{4. 4.0074.china Institute of Geophysics and Geomatics China University of Geosciences Wuhan China Department of Geography Hong Kong Baptist University Hong Kong China State Key Laboratory of Information Engineering in Surveying Mapping and Remote Sensing Wuhan University Wuhan China Hubei Provincial Bureau of Meteorology Wuhan China

The gradient based landscape metrics analysis is now widely used to study the landscape pattern changes in respond to the *** order to discover the trend of spatio-temporal changes in Beijing metropolitan area during the past 15 years,several landscape metrics are computed using a moving window along a 96 km long transect across Beijing metropolitan area from west to ***,the spatial extent of sub-landscape,which is determined by the moving window’s size,is profoundly *** results show that the metrics varies smoothly and regularly along the selected transect when the window size is greater than 6 km×6 km,and irregularly fluctuated for the smaller window size,that the spatial and temporal landscape characteristics of Beijing city match the hypothetical framework of spatio-temporal urban sprawl in the form of alternating processes of diffusion and coalescence well,and that some new trends of the urban sprawl style in Beijing metropolitan area,such as leap-frog manner,are also detected by the gradient landscape analysis.

关键词： gradient analysis landscape metrics spatio-temporal urban expansion multi-extent

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On the new results of global attractive set and positive invariant set of the Lorenz chaotic system and the applications to chaos control and synchronization

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Science in china(Series F) 2005年第3期48卷 304-321页

作者： LIAO Xiaoxin 1, 2. 3 , FU Yuli 4.& XIE Shengli 4.1. Department of Control Science & Control Engineering, Huazhong university of Science & Technology, wuhan {2. {4. 2. School of Automation, wuhan university of Science & Technology, wuhan 4.0070, {4. 3. School of Information, Central South university of Economy, Politics and Law, wuhan 4.0064. {4. 4. School of Electronics & Information Engineering, South {4. university of Technology, Guangzhou 51064., {4. Correspondence should be addressed to Liao Xiaoxin (email: xiaoxin_liao@***) Department of Control Science & Control Engineering Huazhong University of Science & Technology Wuhan China School of Automation Wuhan University of Science & Technology Wuhan China School of Information Central South University of Economy Politics and Law Wuhan China School of Electronics & Information Engineering South China University of Technology Guangzhou China

Constructing a family of generalized Lyapunov functions, a new method is proposed to obtain new global attractive set and positive invariant set of the Lorenz chaotic system. The method we proposed greatly simplifies the complex proofs of the two famous estimations presented by the Russian scholar Leonov. Our uniform formula can derive a series of the new estimations. Employing the idea of intersection in set theory, we extract a new Leonov formula-like estimation from the family of the estimations. With our method and the new estimation, one can confirm that there are no equilibrium, periodic solutions, almost periodic motions, wandering motions or other chaotic attractors outside the global attractive set. The Lorenz butterfly-like singular attractors are located in the global attractive set only. This result is applied to the chaos control and chaos synchronization. Some feedback control laws are obtained to guarantee that all the trajectories of the Lorenz systems track a periodic solution, or globally stabilize an unstable (or locally stable but not globally asymptotically stable) equilibrium. Further, some new global exponential chaos synchronization results are presented. Our new method and the new results are expected to be applied in real secure communication systems.

关键词： Lorenz chaotic system global attractive set positive invariant set globally exponential tracking globally exponential synchronization.

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