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hIGh TEMPERATURE FATIGUE BEhAVIOUR OF A DIRECTIONALLY SOLIDIFIED COBALT-BASE SUPERALLOY

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Acta Metallurgica Sinica(English Letters) 1998年第2期11卷 111-115页

作者： W.h.JIANG X.D.YAO h.R.GUAN Z.Q.hU Chinese Acad of Sciences Shenyang China

The high temperature high cycle fatigue behaviour of a directionally solidified Co-base superalloy was investigated. The alloy has saperior fatigue resistance at 900℃ and its fatigue strength is up to 295MPa. Its σ-Nf curve is characterized by three distinct zones. The stronger dependence of Nf on or in the high .and low stress zones results from multiple fatigue crock initiation sites produced by high stress and oxidation effect in a prolonged exposure, respectively.

关键词： directional solidification Co-base superalloy fatigue fracture

Is changing footstrike pattern beneficial to runners?

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Journal of Sport and health Science 2017年第2期6卷 146-153页

作者： Joseph hamill Allison h.Gruber Biomechanics Laboratory Department of KinesiologyUniversity of MassachusettsAmherstMA 01003USA Biomechanics Laboratory Department of KinesiologyIndiana UniversityBloomingtonIN 47405USA

Some researchers, running instructors, and coaches have suggested that the "optimal" footstrike pattern to improve performance and reduce running injuries is to land using a mid-or forefoot strike. Thus, it has been recommended that runners who use a rearfoot strike would benefit by changing their footstrike although there is little scientific evidence for suggesting such a change. The rearfoot strike is clearly more prevalent. The major reasons often given for changing to a mid-or forefoot strike are(1) it is more economical;(2) there is a reduction in the impact peak and loading rate of the vertical component of the ground reaction force; and(3) there is a reduction in the risk of a running-related injuries. In this paper,we critique these 3 suggestions and provide alternate explanations that may provide contradictory evidence for altering one's footstrike *** have concluded, based on examining the research literature, that changing to a mid-or forefoot strike does not improve running economy, does not eliminate an impact at the foot-ground contact, and does not reduce the risk of running-related injuries.

关键词：跑步经济运行运动损伤科学证据研究人员土地使用垂直分量反作用力

Matter and radiation at extremes:Prospects and impacts

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Matter and Radiation at Extremes 2021年第1期6卷 3-4页

作者： Michel Koenig David Crandall ho-Kwang Mao Ke Lan Dieter h.h.hoffmann Weiyan Zhang Laboratoire LULI CNRSCEAEcole PolytechniqueUPMCUniv Paris 06:Sorbonne UniversitesInstitut Polytechnique de ParisF-91128 Palaiseau cedexFrance Independent Consultant Retired from United States Department of EnergyRockvilleMaryland 20850USA Center for high Pressure Science and Technology Advanced Research ShanghaiChina Institute of Applied Physics and Computational Mathematics BeijingChina Center for Applied Physics and Technology Peking UniversityBeijing100871China Xi’an Jiaotong University Xi’anChina China Academy of Engineering Physics MianyangChina

high-energy-density science(hEDS)has been recognized as a comprehensive new area of physical science,with the potential to revolutionize various scientific and technological fields,including nuclear fusion,particle acceleration,astrophysics,and the properties of condensed matter under extreme *** is why this journal,Matter and Radiation at Extremes(MRE),was established five years ago by the China Academy of Engineering Physics(CAEP)with the mission of informing the worldwide scientific community about progress related to hEDS,whether this be in the basic physics.

关键词： conditions. extreme acceleration

STRENGThENING CAST IRON MATRIX BY ALLOYINGELEMENTS WITh POSITIVE AND NEGATIVESEGREGATION

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Acta Metallurgica Sinica(English Letters) 1997年第4期10卷 329-332页

作者： Fan, Z.K. Wang, Y.Q. Liang, S.h. huang, h.S. Xi'an Univ of Technology Xi'an China

The combinational use of alloying elements with positive and negative segregation has been shown to be very effective in strengthening the matrix of cast iron. Negative segregation alloying elements, Cu and Si, make the inner parts of dendritic austenites and eutectic cells get good hardenability. On the contrary, positive segregation alloying elements Cr and Mn make the outer parts of dendrites have higher microhardness. Appropriate combination of the above two types of alloying elements can produce a uniform microhardness and high strength in gray cast irons.

关键词： Cast iron Chromium Copper hardness Manganese Segregation (metallography) Silicon Strengthening (metal)

SITEM for the conformable space-time fractional Boussinesq and(2+1)-dimensional breaking soliton equations

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Journal of Ocean Engineering and Science 2021年第3期6卷 228-236页

作者： h.Çerdik Yaslan Ayse Girgin Department of Mathematics Pamukkale UniversityDenizli 20070Turkey

In the present paper,new analytical solutions for the space-time fractional Boussinesq and(2+1)-dimensional breaking soliton equations are obtained by using the simplified tan(φ(ξ)2)-expansion ***,fractional derivatives are defined in the conformable *** show the correctness of the obtained traveling wave solutions,residual error function is *** is observed that the new solutions are very close to the exact *** solutions obtained by the presented method have not been reported in former literature.

关键词： Space-time fractional Boussinesq equation (2+1)-dimensional breaking soliton equation Simplified tan(φ(ξ)2)-expansion method(SITEM) Conformable derivative.

Possible seismic reflector in the lower crust: Evidence from fabrics and experiments of seismic velocity on layered gabbro at high temperature and high pressure

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Chinese Science Bulletin 2003年第9期48卷 914-920页

作者： OUXingong JINZhenmin JINShuyan h.Kern GraduateSchool ChinaUniversityofGeosciencesWuhan430074China FacultyofEarthSciences ChinaUniversityofGeosciencesWuhan430074China InstitutfürGeowissenschaften UniversitǎtKiel24098KielGermany

Lattice preferred orientations (LPO) of plagioclase and augite are measured on layered gabbro from the Panxi region, Sichuan Province. The LPO concentration [010] of plagioclase and [100] of augite are perpendicular to the foliation, which indicates a kind of growth fabric associated with crystallizing habits of minerals when the magma is solidifying under the compaction. Calculated seismic velocities based on LPO data of minerals give rise to rather strong anisotropy 5.81% and 5.54% for compressional seismic wave (Vp) and shear seismic wave (Vs), respectively. The experiments at high temperature and high pressure show that the P-wave velocity of layered gabbro is 6.44-6.97 km/s with the maximum Vp anisotropy 5.22% and the Poisson's ratio is between 0.28-0.31. According to the comparison of fabrics with seismic velocities of layered gabbro, it is uggested that the large-scale layered intrusive body or the similar layered geological body may exist in the lower crust of this area. Such a layered intrusive body which has strong seismic anisotropy may be the seismic reflector in the lower crust.

关键词：地震反射体地震速率分层辉长石高温高压实验下层地壳格子首选方向各向异性地球物理勘探

Improving the performance of structure-embedded acoustic lenses via gradient-index local inhomogeneities

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International Journal of Smart and Nano Materials 2015年第1期6卷 1-13页

作者： h.Zhu F.Semperlotti Department of Aerospace and Mechanical Engineering University of Notre DameNotre DameIndiana 46556USA

We investigate the use of graded inhomogeneities in order to enhance the focusing and collimation performance of structure-embedded acoustic metamaterial *** type of inhomogeneity exploited in this study consists in axial symmetric exponential-like gradients of either material or geometric properties that create gradient-index inclusions able to bend and redirect propagating *** particular,we exploit the concept of gradient index inclusions to achieve focusing and collimation of ultrasonic beams created by embedded drop-channel lenses in both bulk and thin-walled *** the latter,the implementation is possible thanks to geometric exponential tapers known as Acoustic Black holes(ABh).ABh tapers allow accurate control of the characteristics of the acoustic beam emanating from the lens channel which in the conventional design is severely affected by *** concept of beam control via graded inclusions is numerically illustrated and validated by using a combination of methodologies including geometric acoustics,finite difference time domain,and finite element methods.

关键词： acoustic lens acoustic black hole gradient index inhomogeneity drop-channel acoustic metamaterials

Fine sediment carrying capacity of combined wave and current flows

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International Journal of Sediment Research 2009年第4期24卷 425-438页

作者： Onyx W. h. WAI Department of Civil & Structural Engineering The Hong Kong Polytechnic University

The so-called fine sediment in many coastal areas and estuaries in China is mostly referred to the mixture of cohesive sediment and non-cohesive sediment. To predict the mixed type fine sediment transport, sediment carrying capacity formulae combined with the 2-D suspended sediment transport equation and morphologic equation have been widely used in China. In the present study, the sediment carrying capacity formula suggested by Dou et al. (1995) for wave conditions has been improved and implemented for the prediction of sediment transport in nearshore regions where wave activities are significant. The improvement is based on the wave energy dissipation principle inside and outside the surf zone. In the improved formula, sediment in suspension increases with the magnitude of the wave period and this feature complies with general observations. More than 300 laboratory and field measured data sets have been reviewed and 12 of them have been used to verify and determine the major coefficients in the improved formula. The application of the sediment carrying capacity model in combined wave and current situations shows that the model can faithfully reproduce the cross-shore sediment concentration distributions at the southwest coast of Bohai Bay.

关键词： Sediment carrying capacity Combined wave and current Sediment transport Fine sediment Bohai Bay Surf zone

心脏外科手术中的过敏反应：对临床医生的启示

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麻醉与镇痛 2009年第2期5卷 18-30页

作者： Jerrold h. Levy, md N. Franklin Adkinson, Jr., md 颜学滔(译) 张力(译) Emory University School of Medicine Atlanta Georgia and Johns hopkins Asthma & Allergy Center Division Allergy & Clinical Immunology Baltimore Maryland 不详

手术过程中，患者与麻醉药物、抗生素、血液制品、肝素、多肽（如抑肽酶、乳胶、鱼精蛋白）以及血容量扩充剂等多种外源性物质相接触，这些药物可能引发致命的“过敏”性变态反应。围手术期过敏反应主要表现为急性心肺功能障碍。心脏手... 详细信息

手术过程中，患者与麻醉药物、抗生素、血液制品、肝素、多肽（如抑肽酶、乳胶、鱼精蛋白）以及血容量扩充剂等多种外源性物质相接触，这些药物可能引发致命的“过敏”性变态反应。围手术期过敏反应主要表现为急性心肺功能障碍。心脏手术的患者由于有全面的监测，过敏反应一旦发生，能够被快速识别并加以治疗。由于使用治疗剂量之前，先给予患者小剂量药物（常称为试验量）即可能引发过敏反应，因此，临床医生必须随时准备应对可能发生的过敏反应。对于血流动力学不稳定的患者，建立心肺转流不失为一种拯救生命的策略，尤其适用于顽固性心血管功能失代偿的患者。对于血管扩张性休克者，还应考虑使用精氨酸加压素。本篇综述着重围绕心脏手术患者，针对手术室内具有过敏危险的患者，探讨过敏发生率和过敏处理措施的新理念。

关键词：过敏反应临床医生心脏外科手术中血流动力学不稳定血容量扩充剂心肺功能障碍精氨酸加压素