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INVESTIGATION ON HOT DUCTIliTy.AND STRENGTH OF CONTINUOUS CASTING SLAB FOR AH32 STEEL

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Acta Metallurgica Sinica(English Letters) 2006年第1期19卷 75-78页

作者： G. y. li X.F. li L.G. Ao Technology.Center Anshan Iron and Steel Group CorporationAnshan 114009 China

By.means of Gleeble-1500 testing machine, the simulation of continuous casting process forAH32 steel was carried out and hot ductility.and strength were determined. The crack.ng sensitivity.was studied under the different temperatures and strain rates. The Precipitations of AIN at different temperatures and the fractures of high-temperature tensile samples were observed by.using TEM （transmission electron microscope） and SEM （scanning electron microscope）. The factors affecting the brittle temperature zone were discussed.

关键词： continuous casting slab brittle temperature zone tensile strength,ductility simulation

NUCLEATION OF RARE EARTH-RICH PHASE PARTICLES IN Ti-5Al-4Sn-2Zr-1Mo-0.25Si-1Nd ALLOy

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Acta Metallurgica Sinica(English Letters) 1998年第4期11卷 265-269页

作者： G.P.li D.li and y. y. liu (Department of Titanium Alloy., Institute of Metal Research, The Chinese Academy.of Sciences, Sheny.ng 110015, China) Inst of Metal Research The Chinese Acad of Sciences Shenyang China

High resolution electron microscopy.studies of rure earth-rich phase particles in a melt-quenched Ti-5Al-4Sn-2Zr-1MO-0.25Si-1Nd alloy.indicate that the α-Ti matrix cry.tallizes prior to the rare earth-rich phase particles. According to a new nucleation model, the heteropeneous nucleation of the rare earth-rich phase particles at the matrix interface is easier than the homogeneous nucleation off the interface matrix, which is consistent with the results of the HREM obseroations.

关键词： Ti alloy rure earth rich phase nucleation

Effects of hy.teresis of static contact angle (HSCA) and boundary.slip on the hy.rody.amics of water striders

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Acta Mechanica Sinica 2017年第1期33卷 40-61页

作者： J. Zheng B. S. Wang W. Q. Chen X. y. Han C. F. li J. Z. Zhang k. P. y. School of Energy.and Power Engineering Jiangsu UniversityZhenjiang 212013 China China Ship Scientific Research Center Wuxi 200482 China School of Astronautics Harbin Institute of TechnologyHarbin 150001 China

It is k.own that contact lines k.ep relatively.still on solids until static contact angles exceed an interval of hy.teresis of static contact angle (HSCA), and contact angles k.ep changing as contact lines relatively.slide on the solid. Here, the effects of HSCA and boundary.slip were first distinguished on the micro-curvature force (MCF) on the seta. Hence, the total MCF is partitioned into static and dy.amic MCFs correspondingly. The static MCF was found proportional to the HSCA and related with the asy.metry.of the micro-meniscus near the seta. The dy.amic MCF, exerting on the relatively.sliding contact line, is aroused by.the boundary.slip. Based on the Blak.-Hay.es mechanism, the dy.amic MCF was proved important for water walk.ng insects with legs slower than the minimum wave speed . As insects brush the water by.laterally.swinging legs back.ards, setae on the front side of the leg are pulled and the ones on the back.side are pushed to cooperatively.propel bodies forward. If they.pierce the water surface by.vertically.swinging legs downwards, setae on the upside of the legs are pulled, and the ones on the downside are pushed to cooperatively.obtain a jumping force. Based on the dependency.between the slip length and shear rate, the dy.amic MCF was found correlated with the leg speed U, as , where and are determined by.the dimple depth. Discrete points on this curve could give fitted relations as (Suter et al., J. Exp. Biol. 200, 2523-2538, 1997). Finally. the axial torque on the inclined and partially.submerged seta was found determined by.the surface tension, contact angle, HSCA, seta width, and tilt angle. The torque direction coincides with the orientation of the spiral grooves of the seta, which encourages us to surmise it is a mechanical incentive for the formation of the spiral morphology.of the setae of water striders.

关键词： Seta Water strider Hy.teresis of static contact angle (HSCA) Boundary.slip

Cell membrane coating for reducing nanoparticle-induced inflammatory.responses to scaffold constructs

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Nano Research 2018年第10期11卷 5573-5583页

作者： Zhiy.an Fan Peter y. li Junjie Deng Stephen C. Bady.Hao Cheng Department of Materials Science and Engineering Drexel University Philadelphia Pennsylvania 19104 USA Engineering Research Center of Clinical Functional Materials and Diagnosis & Treatment Devices of Zhejiang Province Wenzhou Institute of Biomaterials and Engineering Chinese Academy of Sciences Wenzhou 325011 China

The controlled release of therapeutics from microparticles or nanoparticles （NPs） has been well-studied. Incorporation of these particles inside biomaterial scaffolds is promising for tissue regeneration and immune modulation. However, these particles may.induce inflammatory.and foreign body.responses to scaffold constructs, limiting their applications. Here we show that widely.used poly.lactic-co-gly.olic acid） nanoparticles （PLGA NPs） formed by.double emulsion dramatically.increased neutrophil infiltration and pro-inflammatory.cy.ok.nes in alginate scaffolds 1 day.after the subcutaneous injection of the scaffolds into mice. The coating of red blood cell （RBC） membranes on PLGA NPs completely.eliminated these short-term inflammatory.responses. For a longer term of 10 day., neither PLGA NPs nor RBC membrane-coated NPs exerted a significant effect on the infiltration of neutrophils or macrophages in alginate scaffolds, possibly.due to the degradation and/or clearance of NPs by.infiltrating cells. Despite the extensive exploration of cell membrane-coated NPs, our study.is the first to investigate the effects of cell membrane coating on foreign body.reaction to NPs. By.harnessing the natural biocompatibility.of cell membranes, our strategy.of anti-inflammatory.protection for scaffolds may.be pivotal for many.applications such as those rely.ng on the recruitment of stem cells and/or progenitor ceils to scaffolds.

关键词： regenerative medicine wound healing drug delivery endothelial cell immune tolerance

Behavior of Transversal Crack.on Slab Corner During V-H Rolling Process

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Journal of Iron and Steel Research International 2006年第6期13卷 31-37页

作者： y. Hai-liang liU Xiang-hua li Chang-sheng y. k.saba State k.y.Laboratory.of Rolling and Automation Northeastern University Shenyang 110004 Liaoning China Sumitomo Metal Industries Ltd Fuso-cho 660 AMAGASAKI Japan

The behavior of transversal crack. on the surface of the slab corner during vertical and horizontal （V-H） rolling process with flat vertical roll and groove vertical roll was simulated by.explicit dy.amic finite element method. The closure and growth of crack.and the contact pressure on surfaces of the crack.in contacting zone between slab and roll during rolling process were analy.ed. The results showed that during vertical rolling process, when the groove vertical roll is used, the maximum contact pressure on surfaces of the crack.is 115 MPa, and the closure of crack.is stable when the flat vertical roll is used, the maximum contact pressure on surfaces of the crack.is 70 MPa, and it fluctuates greatly. During horizontal rolling process, when groove vertical roll is used, the contact pressure becomes zero which may.accelerate the growth of crack.when flat vertical roll is used, there is still contact pressure. The cal culated results are in good agreement with the results of test.

关键词： slab crack V-H rolling process FEM

Unraveling the my.tery.of enhanced cell-k.lling effect around the Bragg peak.region of a double irradiation source^(9)C-ion beam

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Chinese Science Bulletin 2005年第22期50卷 2546-2551页

作者： li Qiang y. Furusawa M. k.nazawa A. k.tagawa Institute of Modern Phy.ics Chinese Academy of Sciences Lanzhou 730000 China National Institute of Radiological Sciences Chiba 263-8555. Japan

An enhanced cell-k.lling effect at the penetra- tion depths around the Bragg peak.of a β-delay.d particle decay.9C-ion beam has been observed in our preceding ra- diobiological experiments in comparison with a therapeutic 12C beam under the same conditions, and RBE values of the 9C beam were revealed to be higher than those of the comparative 12C beam by.a factor of up to 2. This study.is aimed at investigating the biophy.ical mechanisms underly.ng the important experimental phenomenon. First of all, a model for calculating the stopping probability.density.of the experimentally.applied 9C beam is work.d out, where all determinants such as the initial momentum spread of the 9C beam, the fluence attenuation with penetration depth due to the projectile-target nuclear reaction and the energy.strag- gling effect are tak.n into account. On the basis of the calcu- lated 9C-ion stopping distribution, it has been found that the area corresponding to the enhanced cell-k.lling effect of the 9C beam appears at the stopping region of the incident 9C ions. The stopping 9C-ion density.in depth, then, is derived from the calculated probability.density. Moreover, tak.ng entrance dose 1 Gy.for the 9C beam as an example, the aver- age stopping 9C-ion numbers per cell at various depths are deduced. Meanwhile, the mean lethal damage events induced by.the 9C and comparative 12C beams at the depths with al- most equal dose-averaged LETs are derived from the meas- ured cell surviving fractions at these depths for the 9C and 12C beams. Under the condition of the same absorbed doses, there are indeed good agreements between the average stop- ping 9C-ion number pre cell and the difference of the mean lethal damage events between the 9C and 12C beams at the depths of similar dose-averaged LETs. It can be inferred that if a 9C ion comes to rest in a cell, the cell would undergo dy. ing. In view of the decay.property.of 9C nuclide, clustered damage would be caused in the cell by.the emitted low-

关键词：放射源细胞损伤离子分布致死因子离子束

Experimental methods for determination of mechanical behaviors of materials at high temperatures via the split Hopk.nson bars

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Acta Mechanica Sinica 2020年第6期36卷 1275-1293,I0003页

作者： Q.B.Dou k.R.Wu T.Suo C.Zhang X.Guo y.Z.Guo W.G.Guo y.L.li School of Aeronautics Northwestern Polytechnical UniversityXi’an710072China Joint International Research Laboratory.of Impact Dy.amics and its Engineering Application Xi’an710072China Shaanxi k.y.Laboratory.of Impact Dy.amics and its Engineering Application Xi’an710072China State k.y.Laboratory.for Strength and Vibration of Mechanical Structures School of AerospaceXi’an Jiaotong UniversityXi’an710049China

Full understanding of the thermomechanical behaviors of materials at high strain rates and high temperatures are of great importance from not only.scientific meaning but also practical value in engineering structure design and safety.*** efforts have been made for abilities of operation the split Hopk.nson bars,the most popular technique for experimental determination of mechanical behaviors of materials over the strain rates from 10^2 to 10^4 s^−1 over the past 70 y.ars,at high temperatures since 1960s.A review of experiment work.is presented in this paper to give an overview of the development of experimental techniques at high temperatures based on Hopk.nson bar *** principles of the split Hopk.nson bar requires the loading bars avoiding temperature gradient or k.eping relatively.low temperature when performing high temperature *** such as performing temperature gradient corrections,rapid heating or using special designed automatically.assembled sy.tems were proposed by.researchers to enable the operation of the split Hopk.nson bars at temperature as high as ***,to the application of high speed photographic technique for capturing the dy.amic deformation process of the specimen in high temperature Hopk.nson bar testing,some k.y.issues of eliminating the strong thermal radiation induced lights oversaturation and de-blurring of images due to insufficient exposure at high temperature and high strain rate condition,as well as fabrication of high contrast speck.e pattern for high temperature digital image correlation measurement were also *** technique can now enable the split Hopk.nson bar testing to be performed at high temperature up to 1873 k.under the loading conditions of compression or tension with the in situ observation and full field measurement of deformation as *** paper concludes with summaries of the most important achievements and highlighting of the prospects,trends and remaining challenge

关键词： Mechanical behaviors Split Hopk.nson bar High strain rate High temperature

Dy.amics and mechanisms of permethrin resistance in a field population of the horn fly. Haematobia irritans irritans

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Insect Science 2009年第2期16卷 175-184页

作者： Andrew y. li k.mberly.H. Lohmey.r J. Allen Miller USDA ARS Knipling-Bushland US Livestock Insects Research Laboratory 2700 Fredericksburg Road Kerrville TX 78028 USA

A study.was conducted at the Pressler ranch, near k.rrville, Texas, USA between 2002 and 2006 to determine the dy.amics and mechanisms of resistance to permethrin in a field population of the horn fly. Haematobia irritans irritans （L.）. Changes of resistance to py.ethroid insecticide associated with use of a pour-on formulation of cy.luthrin in 2002 and use of diazinon ear tags in subsequent y.ars were studied using a filter paper bioassay.technique and a poly.erase chain reaction assay.that detects two sodium channel mutations, k.r and super-k.r resistance alleles. A maximum of 294-fold resistance to permethrin was observed in the summer of 2002. A significant decrease in the resistance level was observed in spring 2003, and resistance continued to decline after animals were treated with diazinon ear tags. In response to py.ethroid treatments, the allelic k.r and super-k.r frequency.increased from 56.3% to 93.8% and from 7.5% to 43.8%, respectively.in 2002, and decreased significantly.in 2003 when the py.ethroid insecticide was no longer used to treat animals. Females were found to have a higher allelic super-k.r frequency.than males in 2002, while no difference was detected between males and females in the allelic k.r frequency. There was a significant positive correlation between frequencies of the sodium channel mutations and levels ofpermethrin resistance, suggesting that the sodium channel mutations, k.r and super-k.r, are the major mechanisms of resistance to py.ethroids in this horn fly.population. Results of sy.ergist bioassay. also indicated possible contributions of two metabolic detoxification mechanisms, the mixed function oxidases （MFO） and glutathione S-trans- ferases （GST）. Compared to a horn fly.infestation of an untreated herd, treatments with the py.ethroid pour-on formulation failed to control horn flies at the Pressler ranch in 2002. Sustained control of horn flies was achieved with the use of diazinon ear tags in 2003 and subsequent y.ars.

关键词： efficacy horn fly insecticide resistance PCR permethrin py.ethroids

Transition of deformation mechanisms from twinning to dislocation slip in nanograined pure cobalt

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Journal of Materials Science & Technology 2022年第26期121卷 124-129页

作者： y.W.Qi Z.P.Luo X.y.li k.Lu Sheny.ng National Laboratory.for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaHefei 230026China

Deformation mechanisms of nanograined and submicron-grained pure cobalt processed by.means of high strain rate shear deformation at cry.genic temperatures were *** analy.is revealed a transition of governing deformation mechanism from deformation twinning and dislocation slip in submicron-grains to and dislocations slip in *** tests illustrated that the Hall-Petch relation slope changes consequently.with the transition of deformation mechanism.

关键词： Nanograin Cobalt Deformation mechanism Hall-Petch relation