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Study of engine noise based on independent component analysis

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第5期8卷 772-777页

作者： HAO Zhi-yong jin Yan yang Chen School of Mechanical and Energy Engineering Zhejiang University Hangzhou 310027 China

Independent component analysis was applied to analyze the acoustic signals from diesel engine. First the basic prin-ciple of independent component analysis (ICA) was reviewed. Diesel engine acoustic signal was decomposed into several inde-pendent components (ICs); Fourier transform and continuous wavelet transform (CWT) were applied to analyze the independent components. Different noise sources of the diesel engine were separated, based on the characteristics of different component in time-frequency domain.

关键词： Acoustic signals Independent component analysis (ICA) Wavelet transform Noise source identification

Rellich type inequalities related to Grushin type operator and Greiner type operator

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Applied Mathematics(A Journal of Chinese Universities) 2012年第3期27卷 353-362页

作者： SHEN Shou-feng jin yong-yang Department of Applied Mathematics Zhejiang University of TechnologyHangzhou 310032China

We prove some sharp Hardy inequality associated with the gradient △γ=（△x,｜x｜γ [x△y） by a direct and simple approach. Moreover, similar method is applied to ob- tain some weighted sharp Rellich inequality related to the Grushin operator in the setting of L^p. We also get some weighted Hardy and Rellich type inequalities related to a class of Greiner type operators.

关键词： Rellich inequality Hardy inequality Grushin type operator Greiner type operator.

Group Classification of Differential-difference Equations： Low-dimensional Lie Algebras

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Acta Mathematicae Applicatae Sinica 2017年第2期33卷 345-362页

作者： Shou-feng SHEN yong-yang jin Department of Applied Mathematics Zhejiang University of Technology Hangzhou 310023 China

Differential-difference equations of the form un = Fn（t, un-1,Un,Unn＋1,Un-1,un,Un＋1） are clas- sifted according to their intrinsic Lie point symmetries, equivalence group and some low-dimensional Lie algebras including the Abelian symmetry algebras, nilpotent nonAbelian symmetry algebras, solvable symmetry algebras with nonAbelian nilradicals, solvable symmetry algebras with Abelian nilradicals and nonsolvable symmetry al- gebras. Here Fn is a nonlinear function of its arguments and the dot over u denotes differentiation with respect to t.

关键词： group classification differential-difference equation equivalence group finite-dimensional Lie algebra.

Hydrogen-induced cracking behaviors of Incoloy alloy 825

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International Journal of Minerals,Metallurgy and Materials 2010年第1期17卷 58-62页

作者： yong-jin yang Ke-wei Gao Chang-feng Chen School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China Department of Materials Science and Technology China University of Petroleum Beijing 102249 China

The effect of hydrogen on the fractttre behaviors of Incoloy alloy 825 was investigated by means of slow strain rate testing （SSRT） Hydrogen was introduced into the sample by electrochemical charging. The results show that surface microcracks form gradually during ag- ing at room temperature when desorption of hydrogen takes place after hydrogen charging at a current density of 5 mA/cm^2 for 24 h. SSRT shows that the increase of ductility loss is significantly obvious as the hydrogen charging current density increases. Scanning electron microscopy （SEM） images reveal ductile fracture in the pre-charged sample with low current densities, while the fracture includes small quasi-cleavage regions and tends to be brittle fracture as the hydrogen charging current density increases to 5 mA/cm^2.

关键词： Incoloy alloy hydrogen-induced cracking diffusible hydrogen slow strain rate testing

Hlder Continuity for a Class of Strongly Degenerate Schrdinger Operator Formed by Vector Fields

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Acta Mathematicae Applicatae Sinica 2013年第2期29卷 281-288页

作者： yong-yang jin Jie-lin L Rong-fei LIN Department of Applied Mathematics Zhejiang University of Technology Zhejiang Vocational College of Commerce Department of Mathematics Taizhou University

In this paper we obtain the H61der continuity property of the solutions for a class of degenerate Schr6dinger equation generated by the vector fields：∑i,j=1^m Xj^＊（aij（x）Xiu）＋bXu=uu=0,where X = {X1,.-. ,Xm} is a family of C^∞ vector fields satisfying the H6rmander condition, and the lower order terms belong to an appropriate Morrey type space.

关键词： Hoe1der continuity degenerate SchrSdinger operator green function

Synthesis of Iron Chlorophyllins and Their Catalytic Performance for Aerobic Oxidation of Cyclohexene

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Chemical Research in Chinese Universities 2013年第3期29卷 526-532页

作者： LIU Xiao-hong LI yong-jin yang Wei-jun GUO Can-cheng College of Chemistry and Chemical Engineering Hunan University Changsha 410082 P. R. China

A series of iron（III） chlorophyllins was prepared from silkworm excrement crude chlorophyll extract as a raw material. Aerobic oxidation of cyclohexene by using the prepared iron（III） chlorophyllins as biomimetic catalysts was studied under atmospheric pressure in the absence of reducing agent and solvent. The results indicate that chloro- phyll iron porphyrins have better catalytic performance than the industrial-applied iron tetraphenylporphyrin and cobalt tetraphenylporphyrin, and possess a higher selectivity for 2-cyclohexen-1-one. The smaller the polarity of iron（III） chlorophyllin＇s ligand is, the easier the catalytic oxidation of cyclohexene will be. Esterification products of iron（III） chlo- rophyllins can catalyze the oxidation of cyclohexene better than non-esterified iron（III） chlorophyllins, and therefore show a higher conversion of cyclohexene and a higher selectivity for 2-cyclohexen-l-one than the non-esterified ones. Among the six synthesized iron（III） chlorophyllin catalysts, iron（III） methyl-pyropheophorbide-a is the best biomimetic catalyst for the highest conversion of cyclohexene. The influences of catalyst＇s substituent, polarity and ring structure on the catalytic performance were discussed. The catalytic performance of iron（III） chlorophyllins improves with decreasing polarity, increasing conjugated degree of porphyrin＇s ring or enhancing chlorophyllins＇ stability. Possible mechanism of cyclohexene aerobic oxidation catalyzed by iron（III） chlorophyllins was also discussed.

关键词： Chlorophyll Iron chlorophyltin Air Cyclohexene Catalytic oxidation

Individual-based simulation of the diffusion process of Eupatorium adenophorum

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Forestry Studies in China 2013年第1期15卷 49-55页

作者： Ya-Qian FANG jin-yong yang Qing ZHANG School of Sciences Beijing Forestry University

In order to investigate the diffusion patterns of Eupatorium adenophorum, this study uses a computer to simulate various plant diffusion processes under different environments. The study develops binary cellular automata as a framework reflecting the growth and semination of plants by the change of cellular state and transition function. This model allocates 16 integers, namely 1 to 16, to indicate a life history of plant starting from seed. In each iteration （a year）, Monte-Carlo simulation is applied to decide whether an individual survives into the next year, the probability of which is estimated from previous literature. If a plant survives youth, mature or senile period, its propagation will also be considered and short-tailed dispersal kernel was employed. Applying this basic model, this study also simulates the diffusion process of E. adenophorum under four typical ecological environments. Examining the age structure of the four populations, we found that, although with significantly different numbers of plants left, most individuals were in the infancy period. Besides, their dispersal velocity showed different periodic law. These observations provided reasonable suggestions on what control strategies to be taken respectively.

关键词： Eupatorium adenophorum binary cellular automata short-tailed dispersal kernel age structure velocity of front line

Broadband low-frequency sound absorption of multifunctional composite metastructure

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Science China(Technological Sciences) 2025年第2期68卷 114-124页

作者： Yilong yang Shanshan LIU Yan LI Tong GAO yongdong PAN yong LI Yabin jin School of Aerospace Engineering and Applied Mechanics Tongji UniversityShanghai 200092China State International Joint Research Center of Aerospace Design and Additive Manufacturing Northwestern Polytechnical UniversityXi’an 710072China Institute of Acoustics School of Physics Science and EngineeringTongji UniversityShanghai 200092China Shanghai Key Laboratory of Intelligent Sensing and Detection Technology School of Mechanical and Power EngineeringEast China University of Science and TechnologyShanghai 200237China Shanghai Institute of Aircraft Mechanics and Control Shanghai 200092China

In this study,we fabricated multifunctional metastructures from carbon fiber-reinforced plastic composites using additive manufacturing *** metastructures are characterized by their lightweight,load-bearing capacity,and broadband low-frequency sound absorption *** metastructure consists of 36 unit cells,and non-local coupling mechanism was considered for designing the sound absorption *** developed an acoustic impedance theory tailored for the metastructure,facilitating an analysis of thermal and viscous dissipation *** is proven theoretically and experimentally that the proposed composite metastructure can achieve a noise reduction with an average sound absorption coefficient greater than 0.9 across frequencies in the rage of 330-1500 *** also studied the metastructure’s quasi-static and cyclic compression performance,confirming its efficient absorption capabilities after cyclic *** proposed design and additive manufacturing method for composite metastructures provides a novel pathway for creating lightweight,multifunctional structures with diverse applications,such as aerospace engineering.

关键词： composite metastructure broadband sound absorption additive manufacturing

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THE CONVEX SETS OF CONSTANT WIDTH CONSTRUCTED FROM OPPOSITE SECTORS

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Acta Mathematica Scientia 2025年第1期45卷 118-125页

作者： Fengfan XIE yong yang Hubei Province Key Laboratory of Systems Science in Metallurgical Process(Wuhan University of Science and Technology) Wuhan430081China Henan University of Animal Husbandry and Economy Zhengzhou450046China

This paper presents a method for constructing a convex set of constant width from opposite sectors.

关键词： convex set constant width opposite sectors