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The natur. of near.wall convection velocity in tur.ulent channel flow

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Acta Mechanica Sinica 2008年第5期24卷 587-590页

作者： Yuhui Cao Jun Chen Zhensu she State Key Labor.tor. for.Tur.ulence r.sear.h and ComplexSystem College of Engineering Peking UniversityBeijing 100871 China Depar.ment of Mathematics University of California at Los AngelesLos Angeles CA 90095 USA

A novel notion of tur.ulent str.ctur. the local cascade str.ctur.-is intr.duced to study the convection phenomenon in a tur.ulent channel flow. A space-time cr.ss-cor.elation method is used to calculate the convection velocity. It is found that ther. ar. two char.cter.stic convection speeds near.the wall, one associated with small-scale str.aks of a lower.speed and another.with str.amwise vor.ices and hair.in vor.ices of a higher.speed. The new concept of tur.ulent str.ctur. is power.ul to illustr.te the dominant r.le of coher.nt str.ctur.s in the near.wall convection, and to r.veal also the natur. of the convection-the pr.pagation of patter.s of velocity fluctuations-which is scale-dependent.

关键词： Tur.ulent str.ctur. Cascade Str.ctur. classification Convection Channel flow

Dynamics of a non-autonomous density-dependent pr.dator.pr.y model with Beddington-DeAngelis type

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Inter.ational Jour.al of Biomathematics 2016年第4期9卷 15-39页

作者： Haiyin Li Zhikun she LMIB and School of Mathematics and Systems Science Beihang Univer.ity Beijing P. R. China Depar.ment of Mathematics and Infor.ation Henan Univer.ity of Economics and Law Zhengzhou P. R. China

The goal of this paper.is to investigate the dynamics of a non-autonomous density- dependent pr.dator.pr.y system with Beddington-DeAngelis functional r.sponse, wher. not only the pr.y density dependence but also the pr.dator.density dependence ar. consider.d, such that the studied pr.dator.pr.y system confor.s to the r.alistically biological envir.nment. We fir.tly intr.duce a sufficient condition for.the per.anence of the system and then use a specific set to obtain a weaker.sufficient condition. After.ar., we pr.vide cor.esponding conditions for.the extinction of the system and the existence of boundar. per.odical solutions, r.spectively. ~r.her. we get a sufficient condition for.global attr.ctiveness of the boundar. per.odic solution by constr.cting a Lyapunov function, ar.iving at the uniqueness of boundar. per.odic solutions since the uniqueness of boundar. per.odic solutions can be ensur.d by global attr.ctiveness. finally, based on the existence of positive per.odic solutions, which can be ensur.d by the Br.uwer.fixed- point theor.m, we pr.vide a sufficient condition for.the uniqueness of positive per.odic solutions.

关键词： Per.anence Beddington-DeAngelis functional r.sponse global attr.ctive-ness uniqueness of per.odic solutions.

Vision-Based Adaptive Pr.scr.bed-Time Contr.l of UAV for.Uncooper.tive Tar.et Tr.cking with Per.or.ance Constr.int

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Jour.al of Systems Science & Complexity 2024年第5期37卷 1956-1977页

作者： she Xuehua MA Hui r.N Hongr. LI Hongyi School of Automation and the Guangdong Pr.vincial Key Labor.tor. of Intelligent Decision and Cooper.tive Contr.l Guangdong University of TechnologyGuangzhou 510006China School of Mathematics and Statistics Guangdong University of TechnologyGuangzhou 510006China College of Electr.nic and Infor.ation Engineer.ng and Chongqing Key Labor.tor. of Gener.c Technology and System of Ser.ice r.bots Southwest UniversityChongqing 400715China

This paper.discusses the uncooper.tive tar.et tr.cking contr.l pr.blem for.the unmanned aer.al vehicle(UAV)under.the per.or.ance constr.int and scaled r.lative velocity constr.int,in which the states of the uncooper.tive tar.et can only be estimated thr.ugh a vision *** the limited detection r.nge,a pr.scr.bed per.or.ance function is designed to ensur. the tr.nsient and steady-state per.or.ances of the tr.cking ***,the scaled r.lative velocity constr.int in the dynamic phase is taken into account,and a time-var.ing nonlinear.tr.nsfor.ation is used to solve the constr.int pr.blem,which not only over.omes the feasibility condition but also fails to violate the constr.int ***,the pr.ctically pr.scr.bed-time stability technique is incor.or.ted into the contr.ller.design pr.cedur. to guar.ntee that all signals within the closed-loop system ar. *** is pr.ved that the UAV can follow the uncooper.tive tar.et at the desir.d r.lative position within a pr.scr.bed time,ther.by impr.ving the applicability of the vision-based tr.cking *** r.sults have been pr.sented to pr.ve the validity of the pr.posed contr.l str.tegy.

关键词： Nonlinear.tr.nsfor.ation per.or.ance constr.int pr.scr.bed-time tr.cking uncooper.tive tar.et vision-based measur.ment

A moment-based stochastic edge-based smoothed finite element method for.electr.magnetic for.ing pr.cess

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Science China(Technological Sciences) 2020年第9期63卷 1739-1750页

作者： YANG Qin WANG Bing LI she CUI XiangYang State Key Labor.tor. of Advanced Design and Maufactur.ng for.Vehicle Body Hunan UniversityChangsha 410082China

In this paper. a novel stochastic method named as the moment-based stochastic edge-based finite element method(MSES-fEM)is pr.posed to deal with the uncer.ain electr.magnetic pr.blems. fir.t, electr.magnetic and mechanical field ar. for.ulated by smoothed Galer.in Weak for. under.edge-based smoothed finite element method(ES-fEM) scheme. The moment analysis is then applied to obtain the fir.t four.moments of the r.sponses and to obser.e the effects of each r.ndom var.able on electr.magnetic field r.sponses. The maximum entr.py theor. is employed to calculate the pr.bability density functions(PDfs) of the r.sponses. A quasi-static electr.magnetic pr.blem and a pr.ctical electr.magnetic for.ing pr.blem(EMf) ar. per.or.ed. The pr.posed method successfully solves stochastic electr.magnetic for.ing analysis under.the uncer.ain par.meter.. Numer.cal r.sults obtained by the pr.posed MSES-fEM ar. quite satisfactor. with the ones by the Monte Car.o simulation(MCS).

关键词： MSES-fEM electr.magnetic for.ing pr.blem the moment analysis the maximum entr.py theor. pr.bability density function

A sur.ey on r.n-time suppor.ing platfor.s for.cyber.physical systems

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fr.ntier. of Infor.ation Technology & Electr.nic Engineer.ng 2017年第10期18卷 1458-1478页

作者： Yuan SUN Gang YANG Xing-she ZHOU School of Computer.Science and Engineer.ng Northwestern Polytechnical University Xi'an 710072 China

Cyber.physical systems(CPSs) incor.or.te computation, communication, and physical pr.cesses. The deep coupling and continuous inter.ction between such pr.cesses lead to a significant incr.ase in complexity in the design and implementation of CPSs. Consequently, wher.as developing CPSs fr.m scr.tch is inefficient, developing them with the aid of CPS r.n-time suppor.ing platfor.s can be efficient. In r.cent year., much r.sear.h has been actively conducted on CPS r.n-time suppor.ing platfor.s. However. few sur.eys have been conducted on these platfor.s. In this paper. we analyze and evaluate existing CPS r.n-time suppor.ing platfor.s by fir.t classifying them into thr.e categor.es fr.m the viewpoint of softwar. ar.hitectur.: component-based platfor.s, ser.ice-based platfor.s, and agent-based platfor.s. Then, for.each type, we detail its design philosophy, key technical pr.blems, and cor.esponding solutions with specific use cases. Subsequently, we compar. existing platfor.s fr.m two aspects: constr.ction appr.aches for.CPS tasks and suppor. for.non-functional pr.per.ies. finally, we outline sever.l impor.ant futur. r.sear.h issues.

关键词： Cyber.physical system(CPS) r.n-time suppor.ing platfor.s Component Ser.ice Agent

Accur.tely pr.dicting hyper.onic tr.nsitional flow on cone via a symmetr. appr.ach

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Chinese Jour.al of Aer.nautics 2023年第7期36卷 337-347页

作者： Weitao BI Kexin ZHENG Zhou WEI Zhensu she State Key Labor.tor. for.Tur.ulence and Complex Systems and Depar.ment of Mechanics and Engineer.ng Science College of EngineeringPeking UniversityBeijing 100871China State Key Labor.tor. of Aer.dynamics and Computational Aer.dynamics Institute China Aerodynamics Research and Development CenterMianyang 621000China

A new algebr.ic tr.nsition model is pr.posed based on a Str.ctur.l Ensemble Dynamics(SED)theor. of wall tur.ulence,for.accur.tely pr.dicting the hyper.onic flow heat tr.nsfer.on *** model defines the eddy viscosity in ter.s of a two-dimensional multi-r.gime distr.bution of a Str.ss Length(SL)function,and hence is named as *** paper.pr.sents clear.evidence of pr.cise pr.dictions of tr.nsition onset location and peak heat flux of a wide r.nge of hyper.onic Tr.nsitional Boundar. Layer.(Tr.L)ar.und str.ight cone at zer. incidence,to an unpr.cedented accur.cy as validated by over.70 measur.ments for.var.ing five cr.cial influential factor.(Mach number.temper.tur. r.tio,cone half angle,nose r.ynolds number.and noise level).The r.sults demonstr.te the univer.ality of the postulated multi-r.gime similar.ty str.ctur.,in char.cter.zing not only the spatial non-unifor. distr.bution of the eddy viscosity in hyper.onic Tr.L on cone,but also the dependence of the tr.nsition onset location on the five influential *** latter.yields a novel cor.elation for.ula for.tr.nsition center.r.ynolds number.which takes similar.functional for. as the SL function within the symmetr. *** is concluded that the SED-SL model simulates Tr.L ar.und cone with unifor.ly high accur.cy,and then points out to an optimistic alter.ative way to constr.ct hyper.onic tr.nsition model.

关键词： Cones Heat flux Hyper.onic boundar. layer. Tr.nsition flow Tur.ulence models

Time-var.ing contr.l via nominal tr.jector. linear.zation for.an air.br.athing hyper.onic vehicle

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控制理论与应用（英文版） 2011年第4期9卷 535-540页

作者： Guangfu MA Zhiyong she School of Astr.nautics Harbin Institute of Technology Harbin Heilongjiang 150001 China

A time-var.ing contr.l law via nominal tr.jector. linear.zation for.an air.br.athing hyper.onic vehicle （ABHV） model is applied. feasible guidance command signal ser.als ar. gener.ted by nonlinear.dynamic inver.e （NDI） method consider.ng inter.ctions between aer.dynamic effects and pr.pulsion systems. Multiple-time-scale continuous time-var.ing contr.l, which meets the r.quir.ment with accur.te, r.bust, and decoupled tr.cking of both the commanded tr.jector. and angular.r.te pr.files in the pr.sence of modeling uncer.ainties and exter.al distur.ances ar. applied. The simulations for.an ABHV model with modeling uncer.ainties, wind gust, and measur.ng noises ar. pr.sented to demonstr.te the capacity and r.liability of this pr.posed method.

关键词： flight contr.l NDI r.bustness Hyper.onic ABHV Multiple time scale

Influence of Non-unifor. Par.meter.of Bolt Joint on Complexity of fr.quency Char.cter.stics of Cylindr.cal shell

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Chinese Jour.al of Mechanical Engineer.ng 2023年第2期36卷 206-219页

作者： Qiansheng Tang Houxin she Chaofeng Li Bangchun Wen School of Engineer.ng Anhui Agricultural UniversityHefei 230036China School of Mechanical Engineer.ng and Automation Northeastern UniversityShenyang 110819China Key Labor.tor. of Vibr.tion and Contr.l of Aer.‑Pr.pulsion System Ministry of EducationNortheastern UniversityShenyang 110819China

Bolt connection is one of the main fixing methods of cylindr.cal shell str.ctur.s.A typical bolted connection model is consider.d as a tuned ***,in the actual wor.ing conditions,due to the manufactur.ng er.or.installation er.or.and uneven mater.als of bolts,ther. ar. always r.ndom er.or. between differ.nt *** investigate the influence of non-unifor. par.meter. of bolt joint,including the stiffness and the distr.bution position,on fr.quency complexity char.cter.stics of cylindr.cal shell thr.ugh a statistical method is the main aim of this *** bolted joints consider.d her. wer. simplified as a ser.es of spr.ngs with r.ndom *** vibr.tion equation of the bolted joined cylindr.cal shell was der.ved based on Sander.’thin shell *** Monte Car.o simulation and statistical theor. wer. applied to the statistical analysis of mode char.cter.stics of the ***,the fr.quency and mode shape of the tuned system wer. investigated and compar.d with ***,the effect of the r.ndom distr.bution and the r.ndom constr.int stiffness of the bolts on the fr.quency and mode shape wer. *** the statistical analysis on the natur.l fr.quencies was evaluated for.differ.nt mistuned *** some special cases wer. pr.sented to help under.tand the effect of r.ndom *** r.sear.h intr.duces r.ndom theor. into the modeling of bolted joints and pr.poses a r.fer.nce r.sult to inter.r.t the complexity of the modal char.cter.stics of cylindr.cal shells with non-unifor. par.meter. of bolt joints.

关键词： Bolted joint r.ndom mistuning shell vibr.tion Mode shape Statistical analysis

Car.on Monoxide-induced Stomatal Closur. Involves Gener.tion of Hydr.gen Per.xide in Vicia faba Guar. Cells

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Jour.al of Integr.tive Plant Biology 2008年第12期50卷 1539-1548页

作者： Xiao-Ping she Xi-Gui Song School of Life Sciences Shaanxi Normal University Xi'an 710062 China

Her. the r.gulator. r.le of CO dur.ng stomatal movement in Vicia faba L. was sur.eyed. r.sults indicated that, like hydr.gen per.xide （H2O2）, CO donor.HemaUn induced stomatal closur. in dose- and time-dependent manner.. These r.sponses wer. also pr.ven by the addition of gaseous CO aqueous solution with differ.nt concentr.tions, showing the fir.t time that CO and H2O2 exhibit the similar.r.gulation r.le in the stomatal movement. Mor.over. our.data showed that ascor.ic acid （ASA, an impor.ant r.ducing substr.te for.H2O2 r.moval） and diphenylene iodonium （DPI, an inhibitor.of the H2O2-gener.ting enzyme NADPH oxidase） not only r.ver.ed stomatal closur. by CO, but also suppr.ssed the H2O2 fluor.scence induced by CO, implying that CO induced-stomatal closur. pr.bably involves H2O2 signal. Additionally, the CO/NO scavenger.hemoglobin （Hb） and CO specific synthetic inhibitor.ZnPPIX, ASA and DPI r.ver.ed the dar.ness-induced stomatal closur. and H2O2 fluor.scence. These r.sults show that, per.aps like H2O2, the levels of CO in guar. cells of V. faba ar. higher.in the dar. than in light, HO-1 and NADPH oxidase ar. the enzyme systems r.sponsible for.gener.ting endogenous CO and H2O2 in dar.ness r.spectively, and that CO is involved in dar.ness-induced H2O2 synthesis in V. faba guar. cells.

关键词： car.on monoxide guar. cells hydr.gen per.xide signaling stomata.