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Experimental Study on Geometry Characteristics of Turbulent Premixed Flames for Natural Gas/Air Mixtures

Journal of Thermal Science 2025年第1期 268-282页

作者： ZHENG Weilin WANG Qijiao XIAO Huahua CHEN Xiaoxiao xie Fan ZENG Wen Liaoning Key Lab of Advanced Test Technology for Aerospace Propulsion System Shenyang Aerospace University State Key Laboratory of Fire Science University of science and Technology of China AVIC Shenyang Aircraft Design and Research Institute

In this study,focusing on the geometry characteristics of spherical expanding flame,the turbulent premixed flames of natural gas/air mixtures were investigated in a fan-stirred turbulent *** effects of initial temperature（T=300-400 K）,initial pressure（P=0.1-0.3 MPa）,turbulence intensity（u'=1.0-2.7 m/s）,oxygen volumetric percentage(φ（O2）=15%-21%) and carbon dioxide volumetric percentage(φ（CO2）=0-20%)were delved *** flame profile under the Cartesian coordinate system was derived from the schlieren images taken by the high-speed ***,from both macroscopic and microscopic perspectives,the influence of experimental conditions on the flame geometry characteristics was explored through flame front extraction,wavelet decomposition and network *** results demonstrate that for significant flame wrinkling,changes in species concentrations and turbulence intensity have more pronounced effects on the flame wrinkling *** wrinkling of the flame front maintains a certain degree of similarity,as evidenced by the locally concentrated distribution of the angles of the maximum fluctuation *** disturbance energy under large-scale（D6-D8） disturbances exhibits relatively high values with a similar trend,exerting a significant impact on the geometry characteristics of the flame *** peaks of correlation degree are scattered either with the decomposition scale or the development of flame radius,indicating no linear correlation between different detail ***,the probability distribution of node degrees in key wrinkled regions exhibits different trends with that of large-scale wrinkling and disturbance energy,especially with changes in initial *** occurs because the number of key wrinkles varies based on the perturbation's strength or the region's ***,an increase in the fluctuation frequency of the flame's local radius may not necessarily lead to an increase in the number of key folded regions.

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Formation of FeNi metal nodules in the Jilin H5 chondrite,the largest stone meteorite in the world

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Acta Geochimica 2023年第6期42卷 961-970页

作者： Xiande xie Key Laboratory of Mineralogy and Metallogeny/Guangdong Provincial Key Laboratory of Mineral Physics and Materials Guangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640China

The Jilin H5 chondrite, the largest known stony meteorite in the world, with its No.1 fragment weighing1770 kg. It contains submillimeter-to centimeter-sized FeNi metal particles/nodules. Our optical microscopic and electron microprobe analyses revealed that the formation of metal nodules in this meteorite is a complex and long-term process, The early stage is the thermal diffusion-caused migration and concentration of dispersed metallic material along fractures to form root-hair shaped metal grains during thermal metamorphism of this meteorite. The later two collision events experienced by this meteorite led to the further migration and aggregation of metallic material into the shock-produced cracks and openings to form largersized metal grains. The shock-produced shear movement and frictional heating occurred in this meteorite greatly enhanced the migration and aggregation of metallic material to form the large-sized nodules. It was revealed that the metal nodule formation process in the Jilin H5 chondrite might perform in the solid or subsolidus state, and neither melting of chondritic metal grains nor shock-induced vaporization of bulk chondrite material are related with this process.

关键词： Jilin chondrite Metal nodules Thermal diffusion Shock metamorphism Shear movement Frictional heating

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Insight into the chemomechanical coupling mechanism of kinesin molecular motors

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Communications in Theoretical Physics 2021年第5期73卷 157-171页

作者： Ping xie Key Laboratory of Soft Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China

Kinesin is a two-headed biological molecular motor that can walk processively on microtubule via consumption of ATP *** central issue for the molecular motor is how the chemical energy released from ATP hydrolysis is converted to the kinetic energy of the mechanical motion,namely the mechanism of chemomechanical *** address the issue,diverse experimental methods have been employed and a lot of models have been *** review focuses on the proposed models as well as the qualitative and quantitative comparisons between the results derived from the models and those from the structural,biochemical and single-molecule experimental studies.

关键词： molecular motor kinesin dynamics mechanochemistry mechanism catch bond

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Web mining based on chaotic social evolutionary programming algorithm

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Journal of Systems Engineering and Electronics 2008年第6期19卷 1272-1276页

作者： xie Bin School of Management Northwestern Polytechnical Univ. Xi'an 710072 P. R. China

With an aim to the fact that the K-means clustering algorithm usually ends in local optimization and is hard to harvest global optimization, a new web clustering method is presented based on the chaotic social evolutionary programming （CSEP） algorithm. This method brings up the manner of that a cognitive agent inherits a paradigm in clustering to enable the cognitive agent to acquire a chaotic mutation operator in the betrayal. As proven in the experiment, this method can not only effectively increase web clustering efficiency, but it can also practically improve the precision of web clustering.

关键词： web clustering chaotic social evolutionary programming K-means algorithm

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The contribution of Asian scientists to global research in andrology

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Asian Journal of Andrology 1999年第1期1卷 7-12页

作者： Geoffrey mh WAITES Clinic for Infertility and Gynaecological Endocrinology University Hospital of Geneva SWITZERLAND and Department of Medicine Unnversity of Sydney Sydney NSW 2006 AUSTRALIA

Aim: To present a personal account of the involvement of the World Health Organization (WHO) in the collaborativedevelopment in Asia of those areas of andrology concerned with male contraception and reproductive ***: The andrology training through workshops and institution support undertaken by the WHO HumanReproduction Programme (HRP) and how they contributed to the strengthening of andrology research in Asia aresummarised. Results: The author's experience and the Asian scientific contributions to the global research in thefollowing areas are reviewed: the safety of vasectomy and the development of new methods of vas occlusion; gossypoland its failure to become a safe, reversible male antifertility drag; Tripterygium and whether its pure extracts will passthrough the appropriate toxicology and phased clinical studies to become acceptable contraceptive drugs; hormonalmethods of contraception for men. Conclusion: The WHO policy of research capacity building through training andinstitution strengthening, together with the collaboration of Asian andrologists, has created strong National institutionsnow able to direct their own programmes of research in clinical and scientific andrology.

关键词： andrology Asia contraception vas occlusion gossypol Tripterygium hormonal methods World Health Organization

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The shift of biogeochemical cycles indicative of the progressive marine ecosystem collapse across the Permian-Triassic boundary:An analog to modern oceans

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Science China Earth Sciences 2018年第10期61卷 1379-1383页

作者： Shucheng xie State Key Laboratory of Biogeology and Environmental Geology China University of Geosciences

Global warming,the most severe faunal mass extinction and the shift of biogeochemical cycles were observed in the ocean across the Permian-Triassic boundary about 252 million years ago,providing an analog to understanding the modern *** with the progressive global warming,the biogeochemical cycle was documented to show a shift from the decoupled processes of carbon,nitrogen and sulfur prior to the mass extinction to the coupled biogeochemical processes during faunal mass *** coupled biogeochemical cycle was further observed to shift from the coupled C-N processes during the first episode of the faunal mass extinction to the coupled C-N-S processes during the second episode,diagnostic of the progressive development of more deteriorated marine environmental conditions and the more severe biotic crisis across the Permian-Triassic *** biogeochemical cycles could thus be an indication to the progressive collapse of marine ecosystems triggered by the global warming in Earth *** modern oceans,the coupled C-N cycle triggered by the global warming was observed in some *** these local C-N processes develop and expand to the global oceans,the coupled C-N-S processes might be brought into existence and the marine ecosystems are inevitable to suffer from complete collapse as observed at 252 million years ago.

关键词： Microbes Mass extinction Permian-Triassic boundary Euxinia Global warming Geobiology

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Sharp heat kernel estimates for spectral fractional Laplacian perturbed by gradients

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Science China Mathematics 2020年第11期63卷 2343-2362页

作者： Renming Song Longjie xie Yingchao xie Department of Mathematics University of Illinois at Urbana-ChampaignUrbanaIL 61801USA School of Mathematics and Statistics Jiangsu Normal UniversityXuzhou 221000China

Using Duhamel’s formula,we prove sharp two-sided estimates for the spectral fractional Laplacian’s heat kernel with time-dependent gradient perturbation in bounded C^1,1 *** addition,we obtain a gradient estimate as... 详细信息

关键词： spectral fractional Laplacian Dirichlet heat kernel Kato class gradient estimate

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Polyhedral Feasible Set Computation of MPC-Based Optimal Control Problems

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IEEE/CAA Journal of Automatica Sinica 2018年第4期5卷 765-770页

作者： Lantao xie Lei xie Hongye Su Jingdai Wang State Key Laboratory of Industrial Control Technology Institute of Cyber-Systems and ControlZhejiang UniversityHangzhou 310027China College of Chemical and Biological Engineering Zhejiang UniversityHangzhou 310027China IEEE

Feasible sets play an important role in model predictive control(MPC) optimal control problems(OCPs). This paper proposes a multi-parametric programming-based algorithm to compute the feasible set for OCP derived from MPC-based algorithms involving both spectrahedron(represented by linear matrix inequalities) and polyhedral(represented by a set of inequalities) constraints. According to the geometrical meaning of the inner product of vectors, the maximum length of the projection vector from the feasible set to a unit spherical coordinates vector is computed and the optimal solution has been proved to be one of the vertices of the feasible set. After computing the vertices,the convex hull of these vertices is determined which equals the feasible set. The simulation results show that the proposed method is especially efficient for low dimensional feasible set computation and avoids the non-unicity problem of optimizers as well as the memory consumption problem that encountered by projection algorithms.

关键词： Feasible set computation linear matrix inequalities(LMIs) model predictive control(MPC) polyhedron

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Existence Results of Damped Second Order Impulsive Functional Differential Equations with Infinite Delay

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Acta Mathematicae Applicatae Sinica 2019年第3期35卷 564-579页

作者： Sheng-li xie Yi-ming xie School of Mathematics&Physics Urban Construction CollegeAnhui Jianzhu University School of Civil Engineering Anhui Jianzhu UniversityHefei 230601China

Using the Monch fixed point theorem and progressive estimation method,we study the existence,uniqueness and regularity of mild solutions for damped second order impulsive functional differential equations with infinite delay in Banach *** compactness assumption on associated family of operators and the impulsive term,some restrictive conditions on a priori estimation,noncompactness measure estimation and the impulsive term have not been used,our results are different from some known ***,a noncompact semigroup example explains the obtained results.

关键词： damped second order impulsive functional differential equations mild solution strong solution classical solution measure of noncompactness

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THREE-DIMENSIONAL NUMERICAL MODELLING OF THE WAVE-IN-DUCED RIP CURRENTS UNDER IRREGULAR BATHYMETRY

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Journal of Hydrodynamics 2012年第6期24卷 864-872页

作者： xie Ming-xiao School of Civil Engineering Tianjin University Tianjin Research Institute for Water Transport Engineering Ministry of Transport

A process-based 3-D hydrodynamic model is established to simulate the rip current structures under irregular bathymetry. The depth-varying wave-induced residual momentum, the surface rollers, the turbulent mixing and the wave-current interactions are considered. Experimental datasets are used to validate the model, and it is shown that the model can effectively describe the 3-D structures of the rip currents in both normal and oblique wave incident cases. The flow patterns of the rip currents see various characteristics for different incident wave directions. In the normal incident case, pairs of counter-rotating primary circulation cells are formed, and an offshore rip flow occurs in the embayment troughs. The peak seaward velocities occur at the top of the bed boundary layer, and the undertow is incorporated in addition to the rip currents. In the oblique incident case, the longshore currents are dominant, which result in a meandering flow along the depth contour, and the undertow is weaker compared to that in the normal incident condition.

关键词： rip currents irregular bathymetry 3-D numerical modelling

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