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Nonlinear identification of systems with parametric excitation

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Science China(Technological Sciences) 2011年第8期54卷 2080-2089页

作者： yE Min DOU SuGuang ZHAng Wei ZEng zhigang School of Aeronautics and Astronautics Zhejiang University Hangzhou 310027 China College of Mechanical Engineering Beijing University of Technology Beijing 100124 China

In this paper, the incremental harmonic balance nonlinear identification (IHBNID) is presented for modelling and parametric identification of nonlinear systems. The effects of harmonic balance nonlinear identification (HBNID) and IHBNID are also studied and compared by using numerical simulation. The effectiveness of the IHBNID is verified through the Mathieu-Duffing equation as an example. With the aid of the new method, the derivation procedure of the incremental harmonic balance method is simplified. The system responses can be represented by the Fourier series expansion in complex form. By keeping several lower-order primary harmonic coefficients to be constant, some of the higher-order harmonic coefficients can be self-adaptive in accordance with the residual errors. The results show that the IHBNID is highly efficient for computation, and excels the HBNID in terms of computation accuracy and noise resistance.

关键词： nonlinear system identification incremental harmonic balance parameter excitation nonlinear systems

Strain induced polymorphism and band structure modulation in low-temperature 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene single crystal

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Science China Chemistry 2017年第2期60卷 275-283页

作者： Jianfeng Chen Wen Shi yuqian Jiang Dong Wang zhigang Shuai MOE Key Laboratory of Organic OptoElectronics and Molecular Engineering Department of ChemistryTsinghua UniversityBeijing 100084China National Center for Nanoscience and Technology Beijing 100190China Key Laboratory of Organic Solids Beijing National Laboratory for Molecular Science(BNLMS)Institute of ChemistryChinese Academy of SciencesBeijing 100190China Collaborative Innovation Center of Chemistry for Energy Materials Xiamen UniversityXiamen 351005China

Organic semiconductors are inherently soft,making it possible to increase their mobilities by *** a unique feature can be exploited directly in flexible electronics for improved device *** 2,7-dioctyl[1]benzothieno[3,2-b][1]-benzothiophene derivative,C8-BTBT is one of the best small-molecule hole transport ***,we demonstrated its band structure modulation under strains by combining the non-equilibrium molecular dynamics simulations and first-principles *** found that the C8-BTBT lattice undergoes a transition from monoclinic to triclinic crystal system at the temperature below 160 *** shear and uniaxial strains were applied to the low-temperature triclinic phase of C8-BTBT,and polymorphism was identified in the shear *** band width enhancement is up to 8%under 2%of compressive strain along the x direction,and 14%under 4%of tensile strain along the y *** band structure modulation of C8-BTBT can be well related to its herringbone packing motifs,where the edge to face and edge to edge pairs constitute two-dimensional charge transport pathways and their electronic overlaps determine the band widths along the two directions *** findings pave the way for utilizing strains towards improved performance of organic semiconductors on flexible substrates,for example,by bending the substrates.

关键词： charge transport shear strain polymorphism band structure modulation flexible electronics

The geochemical characteristics and oil-source rock correlation of oilshow from the Majiashan profile, Chaoxian County, South of Anhui Province

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Chinese Journal Of Geochemistry 2008年第1期27卷 53-57页

作者： TAng youjun WEN zhigang ZAN Ling Key Laboratory of Exploration Technologies for Oil and Gas Resources Ministry of Education Department of Geochemistry Yangtze University Jingzhou 434023 China Faculty of Resources and Information Technology China University of Petroleum Beijing102249 China

In the future time the exploration of marine oil and gas will be one of the significant domains in China. In this paper the biomarker assemblage characteristics of oilshow in the Nanlinghu Formation of the Majiashan pro- file, which is located in Chaoxian County, south of Anhui Province, are described in the light of gas chromatogra- phy/mass spectrometric (GCMS) analysis on the qualitative and quantitative basis. Based on the investigation of the biomarker assemblage characteristics of possible source rocks developed in the area studied, a conclusion is drawn that the oilshow was generated from the Nanlinghu Formation source rocks (abbreviated as T1n), instead of the Qixia Formation source rocks (abbreviated as P1q). It is pointed out that the T1n is of strong potential for future oil explora- tion, and therefore much attention should be paid to it.

关键词：地理特征岩石油-水系统安徽省

Flow and sound fields of scaled high-speed trains with different coach numbers running in long tunnel

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Railway Engineering Science 2024年第3期32卷 401-420页

作者： Qiliang Li yuqing Sun Menghan Ouy.ng zhigang y.ng School of Automotive Studies Tongji UniversityShanghai 201804China Shanghai Automotive Wind Tunnel Center Tongji UniversityShanghai 201804China School of Aerospace Engineering and Applied Mechanics Tongji UniversityShanghai 200092China

Segregated incompressible large eddy simulation and acoustic perturbation equations were used to obtain the flow field and sound field of 1:25 scale trains with three,six and eight coaches in a long tunnel,and the aerodynamic results were verified by wind tunnel test with the same scale two-coach train ***-averaged drag coefficients of the head coach of three trains are similar,but at the tail coach of the multi-group trains it is much larger than that of the three-coach *** eight-coach train presents the largest increment from the head coach to the tail coach in the standard deviation(STD)of aerodynamic force coefficients:0.0110 for drag coefficient(Cd),0.0198 for lift coefficient(Cl)and 0.0371 for side coef-ficient(Cs).Total sound pressure level at the bottom of multi-group trains presents a significant streamwise increase,which is different from the three-coach *** walls affect the acoustic distribution at the bottom,only after the coach number reaches a certain value,and the streamwise increase in the sound pressure fluctuation of multi-group trains is strengthened by coach *** transform of the turbulent and sound pressures presents that coach number has little influence on the peak frequencies,but increases the sound pressure level values at the tail bogie ***,different from the turbulent pressure,the first two sound pressure proper orthogonal decomposition(POD)modes in the bogie cavities contain 90%of the total energy,and the spatial distributions indicate that the acoustic distributions in the head and tail bogies are not related to coach number.

关键词： Flow and sound fields Scaled high-speed trains Different coach numbers Long tunnel Proper orthogonal decomposition

Influence of Sintering Temperature on Microstructure and Mechanical Properties of Al2O3 Ceramic via 3D Stereolithography

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Acta Metallurgica Sinica(English Letters) 2020年第2期33卷 204-214页

作者： He Li y.ngsheng Liu yansong Liu Kehui Hu zhigang Lu Jingjing Liang Science and Technology on Thermostructural Composite Materials Laboratory Northwestern Polytechnical UniversityXi’an 710072China Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China State Key Laboratory of Tribology Tsinghua UniversityBeijing 100084China Institute of Metal Research Chinese Academy of SciencesShenyang 110016China

In this work,aluminum oxide(Al2O3) ceramic samples were fabricated by 3D stereolithography *** process was followed by debinding and *** addition,the effect of sintering temperature on micro structure and properties was *** strength was observed to increase with increasing sintering temperature due to fewer pores,fewer defects and stronger grain boundary bonding of samples at higher sintering *** flexure strength of 138.5 MPa was obtained when sintering temperature was 150℃.Furthermore,the shrinkage along length direction decreased with the decreasing sintering temperature until reaching minimum value of 1.02% after sintering at 1200℃.After sintering at 1280℃,flexure strength was 24.0 MPa and the shrinkage along length direction was 2.1%,which meets demands of ceramic core.

关键词： Stereolithography Aluminum oxide Sintering temperature Shrinkage 3D

Facile grafting strategy synthesis of single-atom electrocatalyst with enhanced ORR performance

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Nano Research 2020年第6期13卷 1519-1526页

作者： Rui Ding yide Liu Zhiyan Rui Jia Li Jianguo Liu zhigang Zou Jiangsu Key Laboratory for Nano Technology National Laboratory of Solid State MicrostructuresCollege of Engineering and Applied Sciencesand Collaborative Innovation Center of Advanced MicrostructuresNanjing University22 Hankou RoadNanjing210093China

Single-atom catalysts(SACs)have become one of the most considered research directions today,owing to their maximum atom utilization and simple structures,to investigate structure-activity *** the field of non-precious-metal electrocatalysts,atomically dispersed Fe-N4 active sites have been proven to possess the best oxygen reduction *** the majority of preparation methods remains complex and costly with unsatisfy.ng ***,we have designed a surface-grafting strategy to directly synthesize an atomically dispersed Fe-NVC electrocatalyst applied to the oxygen reduction reaction(ORR).Through an esterification process in organic solution,metal-containing precursors were anchored on the surface of carbon *** covalent bonding effect could suppress the formation of aggregated particles during heat *** was further introduced as both a cost-effective nitrogen resource and blocking agent retarding the migration of metal *** optimized catalyst has proven to have abundant atomically dispersed Fe-N4 active sites with enhanced ORR catalytic performance in acid *** method has provided new feasible ideas for the synthesis of SACs.

关键词： esterification grafting single-atom catalysts oxygen reduction reaction fuel cell

Fixed-Time Controller Design for a Quadrotor UAV with Asymmetric Output Error Constraints

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Journal of Systems Science & Complexity 2023年第5期36卷 1981-2000页

作者： WAng Fang MA zhigang ZHOU Chao ZHAng Zheng HUA Changchun ZOng Qun School of Science Yanshan UniversityQinhuangdao 066004China Ocean College Hebei Agricultural UniversityQinhuangdao 066003China School of Electric Engineering Yanshan UniversityQinhuangdao 066004China School of Electrical and Information Engineering Tianjin UniversityTianjin 300072China

In this article,a fixed-time tracking control strategy is proposed for a quadrotor UAV(QUAV)with external disturbance and asymmetric output error ***,a dynamic model of the QUAV is transformed into a strict feedback system with external disturbance,and it is decoupled into attitude subsystem and position subsystem for simplify.ng controller ***,an asymmetric tangent barrier Lyapunov function(ATBLF)is applied to solve the tracking error constraints problem,and a fixed-time control law is ***,a fixed-time disturbance observer(FTDO)is designed to cope with external ***,it is proved that the designed controller guarantees the tracking error remains within the constraint ranges and converges to zero in fixed-time by Lyapunov stability ***,the effectiveness of the proposed control scheme is verified by numerical simulations.

关键词： Asymmetric tangent barrier Lyapunov function(ATBLF) fixed-time disturbance observer(FTDO) output error constraints quadrotor UAV(QUAV)

The Influence of Seafloor Hydrothermal Activity on Major and Trace Elements of the Sediments From the South Mid-Atlantic Ridge

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Journal of Ocean University of China 2017年第5期16卷 775-780页

作者： HUAng Xin CHEN Shuai ZEng zhigang PU Xiaoqiang HOU Qinghua Guangdong Province Key Laboratory for Coastal Ocean Variation and Disaster Prediction Technologies Guangdong Ocean University Key Laboratory of Marine Geology and Environment Institute of Oceanology Chinese Academy of Sciences Laboratory for Marine Mineral Resources Qingdao National Laboratory for Marine Science and Technology

Sediment samples obtained from the South Mid-Atlantic Ridge were analyzed for the major and trace elements by inductively coupled plasma atomic emission spectroscopy and inductively coupled plasma mass spectrometry. Results revealed that the contents of elements(e.g., Fe, Mn, Cu, Zn, V, Co) were high in samples 22V-TVG10 and 26V-TVG05 from the sites near the hydrothermal areas, and low in sample 22V-TVG14, which was collected far from the hydrothermal areas. The contents of Ca, Sr and Ba in the samples showed opposite trends. A positive correlation between the concentrations of metallic elements(Cu, Zn, Co, Ni, Pb, V) and Fe in the samples were observed. These results are consistent with chemical evolution of the dispersing hydrothermal plume.

关键词： Atlantic hydrothermal inductively metallic Sediment viscosity ocean agate Major opposite

Influence of N, P, Fe Nutrients Availability on Nitrogen Metabolism-Relevant Genes Expression in Skeletonema marinoi

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Journal of Ocean University of China 2019年第1期18卷 239-252页

作者： JIng Xiaoli MI Tiezhu ZHEN yu WAng Hualong yU zhigang College of Marine Life Science Ocean University of China Function Laboratory for Marine Ecology and Environmental Science Qingdao National Laboratory for Marine Science and Technology Key Laboratory of Marine Environment and Ecology Ministry of Education College of Environmental Science and Engineering Ocean University of China Key Laboratory of Marine Chemical Theory and Technology Ministry of Education

Nitrogen(N), Phosphorus(P), and Iron(Fe) are essential elements for cellular structure and metabolism. In addition to dissolved inorganic nitrogen(DIN), phytoplankton is able to utilize dissolved organic nitrogen(DON). There is general consensus that both bacteria and higher plants nitrogen metabolism is affected by phosphate availability; this was also found to be true in coccolithophorid. Iron affects the structure and function of ecosystems through its effects on nitrogen metabolism. However, it is unclear how these nutrients affect Skeletonema marinoi's nitrogen metabolism. Here, using RT-qPCR, we investigate effects of N, P, and Fe on S. marinoi's nitrogen metabolism and nitrate reductase activity. These results illuminate that in S. marinoi, various nutrients have direct regulation on these genes expression at the molecular level. The vary.ng degree of responses for these genes expression with differing N sources may act to increase the efficiency of nutrient capture when nitrate is limited. Suitable gene expression occurs at a N/P ratio of 16, which represents the atomic N/P ratio of phytoplankton cells and N/P concentrations in ocean; thus, nitrogen metabolism gene expression should be regulated by the existing N/P ratios in the phytoplankton's internal and external environment. Fe concentration has a direct and significant effect on nitrogen metabolism by regulating gene expression and nitrate reductase activity. Gene expression profiles identified in S. marinoi provide a foundation for understanding molecular mechanisms behind diatom nitrogen metabolism with changing N, P, and Fe nutrients allowing a basic understanding of how diatom growth is affected by nutrient utilization.

关键词： Skeletonema marinoi nitrogen metabolism relative gene expression RT-qPCR