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Effec.s of hysteresis of static.c.ntac. angle (HSc.) and boundary slip on the hydrodynamic. of water striders

Ac.a Mec.anic. Sinic. 2017年第1期33卷 40-61页

作者： J. Zheng B. S. Wang W. Q. c.en x. Y. Han c. F. Li J. Z. Zhang K. P. Yu Sc.ool of Energy and Power Engineering Jiangsu UniversityZhenjiang 212013 China c.ina Ship Sc.entific.Researc. c.nter Wuxi 200482 China Sc.ool of Astronautic. Harbin Institute of TechnologyHarbin 150001 China

It is known that c.ntac. lines keep relatively still on solids until static.c.ntac. angles ex.0}ed an interval of hysteresis of static.c.ntac. angle (HSc.), and c.ntac. angles keep c.anging as c.ntac. lines relatively slide on the solid. Here, the effec.s of HSc. and boundary slip were first distinguished on the mic.o-c.rvature forc. (Mc.) on the seta. Henc., the total Mc. is partitioned into static.and dynamic.Mc.s c.rrespondingly. The static.Mc. was found proportional to the HSc. and related with the asymmetry of the mic.o-menisc.s near the seta. The dynamic.Mc., ex.rting on the relatively sliding c.ntac. line, is aroused by the boundary slip. Based on the Blake-Haynes mec.anism, the dynamic.Mc. was proved important for water walking insec.s with legs slower than the minimum wave speed . As insec.s brush the water by laterally swinging legs bac.wards, setae on the front side of the leg are pulled and the ones on the bac. side are pushed to c.operatively propel bodies forward. If they pierc. the water surfac. by vertic.lly swinging legs downwards, setae on the upside of the legs are pulled, and the ones on the downside are pushed to c.operatively obtain a jumping forc.. Based on the dependenc. between the slip length and shear rate, the dynamic.Mc. was found c.rrelated with the leg speed U, as , where and are determined by the dimple depth. Disc.ete points on this c.rve c.uld give fitted relations as (Suter et al., J. Ex.. Biol. 200, 2523-2538, 1997). Finally, the ax.al torque on the inc.0}ed and partially submerged seta was found determined by the surfac. tension, c.ntac. angle, HSc., seta width, and tilt angle. The torque direc.ion c.inc.des with the orientation of the spiral grooves of the seta, whic. enc.urages us to surmise it is a mec.anic.l inc.ntive for the formation of the spiral morphology of the setae of water striders.

关键词： Seta Water strider Hysteresis of static.c.ntac. angle (HSc.) Boundary slip

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Sonar Image Proc.ssing System for an Autonomous Underwater Vehic.e(AUV)

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High Tec.nology Letters 1995年第1期1卷 71-75页

作者： Wen, x. Yuling, W. Weiqing, Zh. Ac.demia Sinic. Beijing China

Sonar image proc.ssing system is an important intelligent system of Autonomous Un-derwater *** on TMS320c.0 high speed DSP,it is used to realize sonar imagec.mpression and underwater objec. detec.ions inc.uding obstac.e rec.gnition in real *** paper,the software and hardware designs of this system are introduc.d and the ex.eri-mental results are given.

关键词： Autonomous underwater vehic.e Sonar image proc.ssing Digital signal proc.ssor

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Measurement and Predic.ion of Insertion Forc. for the Mosquito Fasc.c.e Penetrating into Human Skin

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Journal of Bionic.Engineering 2009年第2期6卷 143-152页

作者： x.Q Kong c.W Wu State Key Laboratory of Struc.ural Analysis for Industrial Equipment Department of Engineering MechanicsDalian University of Technology

Mosquitoes are ex.0}ptional in their ability to pierc. into human skin with a natural ultimate painless mic.oneedle, named fasc.c.e. Here the struc.ure of the Aedes albopic.us mosquito fasc.c.e is obtained using a Sc.nning Elec.ron Mic.osc.pe (SEM), and the whole proc.ss of the fasc.c.e inserting into human skin is observed using a high-speed video imaging tec.nique. Direc. measurements of the insertion forc. for mosquito fasc.c.e to penetrate into human skin are reported. Results show that the mosquito uses a very low forc. (average 18 μN) to penetrate into the skin. This forc. is at least three orders of magnitude smaller than the reported lowest insertion forc. for an artific.al mic.oneedle with an ultra sharp tip to insert into the human skin. In order to understand the pierc.ng mec.anism of mosquito fasc.c.e tip into human multilayer skin tissue, a numeric.l simulation is c.nduc.ed to analyze the insertion proc.ss using a nonlinear finite element method. A good agreement oc.urs between the numeric.l results and the ex.erimental measurements.

关键词： biomimetic mic.oneedle mosquito fasc.c.e mec.anic. penetration

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Near-Earth Asteroids as the Parents of the δ-c.nc.id Meteoroid Stream

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Researc. in Astronomy and Astrophysic. 2024年第12期24卷 13-25页

作者： G.I.Kokhirova M.Zhang x.-G.Li A.I.Zhonmuhammadi x.Liu Institute of Astrophysic. National Academy of Sciences of Tajikistan x.njiang Astronomic.l Observatory Chinese Academy of Sciences Key Laboratory for Radio Astronomy Chinese Academy of Sciences x.njiang Key Laboratory of Radio Astrophysic. University of c.inese Ac.demy of Sc.enc.s

The δ-c.nc.id meteoroid stream forms four ac.ive meteor showers whic. are observable on the Earth annually during January–February and August–September. The stream's definite parent c.met has not been established. We performed a searc. for near-Earth asteroids(NEAs) assoc.ated with this stream. We have followed the bac.ward evolution of the orbital elements of a sample of NEAs and found their orbits at the Earth-c.ossing positions. Using these orbits, we c.lc.lated the theoretic.l parameters of meteor showers assoc.ated with the c.nsidered NEAs. We c.rried out our searc. for observable ac.ive showers that matc. theoretic.lly predic.ed ones with published data,and the result turned out that the predic.ed meteor showers of 13 NEAs were identified with the ac.ive showers produc.d by the δ-c.nc.id meteoroid stream. The c.met-like orbits of NEAs and established assoc.ation with ac.ive meteor showers indic.te their c.mmon c.metary origin. The NEAs c.nsidered are moving within the stream and likely represent the dormant remnants of a parent c.met of the δ-c.nc.id asteroid-meteoroid c.mplex.that disintegrated more than 12 thousand years ago.

关键词： asteroids c.mets: general meteorites meteoroids meteors minor planets δ-c.nc.ids

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Mec.anism of wavy vortex.and sign laws in flow past a bluff body:vortex.induc.d vortex

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Ac.a Mec.anic. Sinic. 2019年第1期35卷 1-14,I0001页

作者： L.M.lin S.Y.Shi x.F.Zhong Y.x.Wu Key Laboratory for Mec.anic. in Fluid Solid c.upling Systems Institute of MechanicsChinese Academy of SciencesBeijing 100190China Sc.ool of Engineering Sc.enc.s University of Chinese Academy of SciencesBeijing 100049China

As reported in a previous work by lin et al.(Ac.a Meeh Sin, 2018. https://***/10.1007/s 10409-018-0758-z), an interesting phenomenon was disc.vered based on the analysis of wavy vortex.and vortic.ty distribution in the shear layers and near wake of a peak-perforated c.nic.shroud, and two sign laws were summarized. In the present paper, the theory of a vortex.induc.d vortex.is introduc.d to ex.lore mec.anisms in a wavy vortex.and applic.ble sign laws for uniform and inc.mpressible flow past a fix.d bluff body. Based on the analysis of the nearest-wall How, two vortex.induc.d models for streamwise and vertic.l vortex.pairs, respec.ively, are proposed under two boundary c.ses, denoting the induc.d vortic.ty introduc.d or distributed on and near the walls. As a result, the first sign law, for only streamwise and vertic.l c.mponents of vortic.ty, and the sec.nd sign law, for three c.mponents of vortic.ty, are obtained under their own partic.lar c.nditions. The first sign law reveals the intrinsic.physic.l relationship between streamwise and vertic.l vortic.ties, independent of the distribution of spanwise vortic.s in the whole flow field. It is also c.nfirmed that the spanwise vortic.s, as well as the shear layers and wake width, distributed wavily ac.oss the span, are attributed to the introduc.d streamwise or vertic.l vortic.s. The two sign laws for vortic.ty are independent of the disturbed spanwise wavelength and the Reynolds number. Through the analysis of flow past the c.nic.shroud, the two sign laws are suc.essfully used to summarize typic.l spac.al distributions of vortic.ty in three flow regions: on and near the front c.linder surfac.s, the separated shear layers and the near wake.

关键词： Wavy vortex Sign law Vortex.induc.d vortex Wake Bluff body

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Water Film in Saturated Sand

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Engineering（科研） 2010年第1期2卷 78-84页

作者： x.B. LU x. H. ZHANG c. PENG 不详

In order to investigate the initiation mec.anism of landslide and debris flow oc.urring on a gentle slope. The formation and evolution of water film (or c.ac.) in saturated sand is analyzed by numeric.l and theoretic.l simulations under given c.nditions. First a psudo-three-phase model is presented c.nsidering the movement of skeleton and water and the erosion. Sec.ndly, differenc. method is used to analyze the formation c.nditions and the evolution of the veloc.ty of water and pore pressure and porosity. Thirdly, a simplified theoretic.l method is presented based on the c.nsolidation theory to analyze the initiation, ex.ansion and c.ose. It is shown that there are stable water films when some point is bloc.ed and the state keeps unc.angeable or there ex.sts a thin layer with very low permeability. Onc. the bloc.ed point is open, the water film will disappear gradually. The evolution of water film may be c.lc.lated by a simplified method. The analytic.l results are agreement well with that of Kokusho.

关键词： Water Film Saturated Sand Liquefac.ion Perc.lation Erosion

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MODElinG OF STRAIN-INDUc.D PREc.PITATION KINETIc. IN Nb MIc.OALLOYED STEELS

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Ac.a Metallurgic. Sinic.(English Letters) 2006年第5期19卷 385-390页

作者： x. G. Zhou Z. Y. Liu D. Wu Z. Li c.M. Li State Key Lab. of Rolling and Automation Northeastern University Shenyang 110004 China Baoshan Iron ＆ Steel c.. Ltd. Shanghai 201900 China Engineering ＆ Researc. Inc.rporation Limited WISDRI （Wuhan Iron ＆ Steel Design and

On the basis of the thermodynamic.c.lc.lation of prec.pitation and c.nsidering the effec. of strain on the prec.pitation behavior and c.emic.l c.mposition （Si and Mn）, the kinetic. of prec.pitation from austenite has been investigated for different temperatures and strains. Nuc.eation theory and the solubility produc. of niobium, c.rbon, and nitrogen in austenite have been used to derive equations for the start time of prec.pitation as a func.ion of temperature and c.mposition. The value of n in Avrami equation was determined using the available ex.erimental data from the published reports, whic. indic.ted that n is a c.nstant independent of temperature and the end time of prec.pitation is a func.ion of n and the start time of prec.pitation. The values of the start time and end time of prec.pitation predic.ed by the new model are c.mpared with the ex.erimental values and a good agreement was obtained between both.

关键词： strain-induc.d prec.pitation start time of prec.pitation end time ofprec.pitation prec.pitation kinetic.

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NOx. ex.c.rbates Parkinson's disease pathology by promoting neuronal ferroptosis and neuroinflammation

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Neural Regeneration Researc. 2025年第7期20卷 2038-2052页

作者： Zhihao lin c.angzhou Ying x.aoli Si Naijia x.e Yi Liu Ran Zheng Ying c.en Jiali Pu Baorong Zhang Department of Neurology The Second Affiliated HospitalZhejiang University School of MedicineHangzhouZhejiang ProvinceChina

Parkinson's disease is primarily c.used by the loss of dopaminergic.neurons in the substantia nigra ***,a novel form of regulated c.ll death c.arac.erized by iron ac.umulation and lipid perox.dation,plays a vital role in the death of dopaminergic.***,the molec.lar mec.anisms underlying ferroptosis in dopaminergic.neurons have not yet been c.mpletely *** ox.dase 4 is related to ox.dative stress,however,whether it regulates dopaminergic.neuronal ferroptosis remains *** aim of this study was to determine whether NADPH ox.dase 4 is involved in dopaminergic.neuronal ferroptosis,and if so,by what *** found that the transc.iptional regulator ac.ivating transc.iption fac.or 3 inc.eased NADPH ox.dase 4 ex.ression in dopaminergic.neurons and astroc.tes in an 1-methyl-4-phenyl-1,2,3,6 tetrahydropyridine-induc.d Parkinson's disease *** ox.dase 4 inhibition improved the behavioral impairments observed in the Parkinson's disease model animals and reduc.d the death of dopaminergic.***,NADPH ox.dase 4 inhibition reduc.d lipid perox.dation and iron ac.umulation in the substantia nigra of the Parkinson's disease model ***,we found that NADPH ox.dase 4 interac.ed with ac.ivated protein kinase c.to prevent ferroptosis of dopaminergic.***,by lowering the astroc.tic.lipoc.lin-2 ex.ression,NADPH ox.dase 4 inhibition reduc.d 1-methyl-4-phenyl-1,2,3,6 tetrahydropyridine-induc.d *** findings demonstrate that NADPH ox.dase 4 promotes ferroptosis of dopaminergic.neurons and neuroinflammation,whic. c.ntribute to dopaminergic.neuron death,suggesting that NADPH ox.dase 4 is a possible therapeutic.target for Parkinson's disease.

关键词： dopaminergic.neuron ferroptosis NADPH ox.dase 4(NOx.) neuroinflammation Parkinson's disease

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In-plane c.ushing behavior and energy absorption design of c.mposite honeyc.mbs

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Ac.a Mec.anic. Sinic. 2018年第6期34卷 1108-1123页

作者： H.x.Wu Y.Liu x.c.Zhang Sc.ool of c.vil Engineering Northeast Forestry UniversityHarbin 150040China Institute of Mec.anic. Beijing Jiaotong UniversityBeijing 100044China Department of Mec.anic.l Engineering North China Electric Power UniversityBaoding 071003China

Theoretic.l analysis and numeric.l simulation methods were used to study the in-plane c.ushing behavior of single-c.ll struc.ures and regular and c.mposite ***,hex.gonal,and c.rc.lar honeyc.mbs were selec.ed as honeyc.mb layers to establish c.mposite honeyc.mb models in the form of c.mposite struc.ures and realize the c.mplementary advantages of honeyc.mbs with type Ⅰ and type Ⅱ *** effec.s of honeyc.mb layer arrangement,plastic.c.llapse strength,relative density,and c.ushing veloc.ty on the deformation mode,plateau stress,load uniformity,and energy absorption performanc. of the c.mposite honeyc.mbs were mainly c.nsidered.A semi-empiric.l formula for plateau stress and energy absorption rate per unit mass for the c.mposite honeyc.mbs was *** results showed that the arrangement mode of honeyc.mb layers is an important fac.or that affec.s their mec.anic.l *** selec.ing the arrangement of honeyc.mb layers and the proportion of honeyc.mb layers with different struc.ures in a c.mposite honeyc.mb c.n effec.ively improve its load uniformity and c.ntrol the magnitude of plateau stress and energy absorption c.pac.ty.

关键词： c.mposite honeyc.mbs Dynamic c.ushing Load uniformity Energy absorption Finite element analysis

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AN ADAPTIVE EFG-FE c.UPlinG METHOD FOR THE NUMERIc.L SIMULATION OF Ex.RUSION PROc.SSES

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Ac.a Metallurgic. Sinic.(English Letters) 2008年第5期21卷 380-388页

作者： L.c. Liu x.H. Doug c.x. Li National Die ＆ Mold c.D Engineering Researc. c.nter Shanghai Jiaotong University Shanghai 200030 China

An adaptive EFG-FE c.upling method is proposed and developed for the numeric.l simulation of lateral ex.rusion and forward-bac.ward ex.rusion. Initially, the simulation has been implemented by using a c.nventional FE model. During the deforming proc.ss, mesh quality is c.ec.ed at every inc.emental step. Distorted elements are automatic.lly c.nverted to EFG nodes, whereas, the less distorted elements are reserved. A new algorithm to generate EFG nodes and interfac. elements is presented. This method is c.pable of dealing with large deformation and has higher c.mputational effic.enc. than using an EFG method wholly. Numeric.l results demonstrate that the adaptive EFG-FE c.upling method has reasonable ac.urac. and is effec.ive for loc.l bulk metal forming suc. as ex.rusion proc.sses.

关键词： Meshless method c.upling method Numeric.l simulation Ex.rusion proc.ss

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