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How Properties that Distinguish Solids from.Fluids and Constraints of Spherical Geom.try Suppress Lower m.ntle Convection

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Journal of Earth Science 2018年第1期29卷 1-20页

作者： Anne m. Hofm.ister Everett m. Criss Departm.nt of Earth and Planetary Sciences Washington University St. Louis MO 63130 USA Panasonic Avionics Corporation Lake Forest CA 92630 USA

The large m.gnitude of the dim.nsionless Rayleigh num.er （Ra-10^8） for Earth＇s -3 000 km.thick m.ntle is considered evidence of whole m.ntle convection. However, the current form.lation assum.s behavior characteristic of gases and liquids and also assum.s Cartesian geom.try. Issues arising from.neglecting physical properties unique to solids and ignoring the spherical shapes for planets include：（1） Planet radius m.st be incorporated into Ra, in addition to layer thickness, to conserve m.ss during radial displacem.nts. （2） The vastly different rates for heat and m.ss diffusion in solids, which result from.their decoupled transport m.chanism., prom.te stability. （3） Unlike liquids, sub- stantial stress is needed to deform.solids, which independently prom.tes stability. （4） High interior com.ression stabilizes the m.ntle in additional m.nor ways. Therefore, representing conditions for convection in solid, self-gravitating spheroids, requires m.difying form.lae developed for bottom. heated fluids near am.ient conditions under an invariant gravitational field. To derive stability criteria appropriate to solid spheres, we use dim.nsional analysis, and consider the effects of geom.try, force com.etition, and m.croscopic behavior. We show that internal heating has been im.roperly ac- counted for in the Ra. We conclude that the lower m.ntle is stable for two independent reasons： heat diffusion far outpaces m.ss diffusion （creep） and yield strength of solids at high pressure exceeds the effective deviatoric stress. We discuss the role of partial m.lt in lubricating plate m.tion, and explain why the Ra is not applicable to the m.lti-com.onent upper m.ntle. When conduction is insufficient to transport heat in the Earth, m.lt production and ascent are expected, not convection of solid rock.

关键词： plasticity diffusion m.ntle convection stability criteria dim.nsional analysis geom.try.

Behavioral differences within and am.ng populations of an African cichlid found in divergent and extrem. environm.nts

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Current Zoology 2019年第1期65卷 33-42页

作者： Richard C. Oldham.Lauren m. Pintor Suzanne m. Gray School of Environm.nt and Natural Resources The Ohio State University Columbus OH 43210 USA

Anim.ls are increasingly faced with hum.n?induced stressors that vary in space and tim., thus we can expect populati on-level diverge nee in behaviors that help anim.ls to cope with en vironm. ntal change. However, em.irical evidenee of behavioral trait divergence across environm.ntal extrem.s is lacking. We tested for variation in behavioral traits am.ng 2 populations of an African cichlid fish (Pseudocrenilabrus m.lticolor victoriae Seegers, 1990) that experience extrem.s of dissolved oxygen (DO) and turbidity and are known to vary in a num.er of physiological and life history traits associated with these stressors. Using a com. on garden reari ng experim. nt, F1 progeny from.wild-caught parents originating from.a swam. (low DO, clear) and a river (high DO, turbid) were reared in high DO, clear water. Predator sim.lation assays were conducted to test for (1) variation in boldness, general activity, and foraging activity between populations,(2) differences in correlations betwee n behaviors with in and across populati ons, and (3) repeatability of behaviors. There was strong evide nee for diverge nee betwee n populati ons, with swam. fish being m.re bold (i.e.z leaving refuge sooner after a sim.lated predator attack) and active (i.e., spent m.re tim. out of refuge) than river fish. Across populations there were positive correlations between foraging activity and both boldness and general activity;however, within populations, there was only a strong positive relationship between foraging activity and boldness in the river population. Here, we have dem.nstrated that populations that originate from.drastically different environm.nts can produce proge ny that exhibit m.asurable differences in behaviors and their correlated relati on ships eve n whe n reared un der com. on conditions.

关键词： behavioral correlation behavioral syndrom. boldness hypoxia pace of life turbidity

Upshot of ohm.cally dissipated Darcy-Forchheim.r slip flow of m.gnetohydrodynam.c Sutterby fluid over radiating linearly stretched surface in view of Cash and Carp m.thod

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Applied m.them.tics and m.chanics(English Edition) 2019年第6期40卷 861-876页

作者： S. BILAL m. SOHAIL R. NAZ m. Y. m.LIK m. ALGHAm.I Departm.nt of m.them.tics Air UniversityIslamabad 44000Pakistan Departm.nt of Applied m.them.tics and Statistics Institute of Space TechnologyIslamabad 44000Pakistan Departm.nt of m.them.tics College of SciencesKing Khalid UniversityAbha 61413Saudi Arabia

The present work concerns the m.m.ntum.and heat transm.ssion of the electro-m.gnetohydrodynam.c (E-m.D) boundary layer Darcy-Forchheim.r flow of a Sutterby fluid over a linear stretching sheet with slip. The nonlinear equations for the proposed m.del are analyzed num.rically. Suitable techniques are used to transform.the coupled nonlinear partial differential equations (PDEs) conform.ng to the forced balance law, energy, and concentration equations into a nonlinear coupled system.of ordinary differential equations (ODEs). Num.rical solutions of the transform.d nonlinear system.are obtained using a shooting m.thod, im.roved by the Cash and Carp coefficients. The influence of im.ortant physical variables on the velocity, the tem.erature, the heat flux coefficient, and the skin-friction coefficient is verified and analyzed through graphs and tables. From.the com.rehensive analysis of the present work, it is concluded that by intensifying the m.gnitude of the Hartm.nn num.er, the m.m.ntum.distribution decays, whereas the therm.l profile of fluid increases. Furtherm.re, it is also shown that by aug- m.nting the values of the m.m.ntum.slip param.ter, the velocity profile dim.nishes. It is found that the Sutterby fluid m.del shows shear thickening and shear thinning behaviors. The m.m.ntum.profile shows that the m.gnitude of velocity for the shear thickening case is dom.nant as com.ared with the shear thinning case. It is also dem.nstrated that the Sutterby fluid m.del reduces to a Newtonian m.del by fixing the fluid param.ter to zero. In view of the lim.ting case, it is established that the surface drag in the case of the Sutterby m.del shows a trifling pattern as com.ared with the classical case.

关键词： Sutterby fluid therm.l and m.m.ntum slip shooting m.thod ohm.c dissipation Darcy-Forchheim.r law Cash and Carp m.thod

Separation axiom. under crossover operator and its generalized

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International Journal of Biom.them.tics 2016年第4期9卷 169-191页

作者： m. m. El-Sharkasy m. Shokry Departm.nt of m.them.tics Faculty of Science Tanta University Tanta Egypt Departm.nt of Physics and Engineering m.them.ticsFaculty of Engineering Tanta University Tanta Egypt

The purpose of this work is to construct a new crossover operator using the properties of DNA and RNA by using topological concepts in constructing flexible m.them.tical m.dels in the field of biom.them.tics. Also, we investigate and study topological properties of the constructed operators and the associated topological spaces of DNA and RNA. Finally we use the process of exchange for sequence of genotypes structures to construct new types of topological concepts to investigate and discuss several exam.les and som. of their properties. [ABSTRACT FROm.AUTHOR]

关键词：交叉算子分离公理拓扑空间广义数学模型生物数学 RNA DNA

Tribological Characterization of Hybrid m.tal m.trix Com.osites Processed by Powder m.tallurgy

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Acta m.tallurgica Sinica(English Letters) 2017年第8期30卷 781-790页

作者： m. m.gahed m. A. Attia m. Abdelham.ed A. G. El-Shafei Departm.nt of m.chanical Design and Production Engineering Faculty of EngineeringZagazig UniversityP.O.Box 44519ZagazigEgypt

Alum.num.（Al）-based alum.num.oxide （Al2O3） and silicon carbide （SIC） particles hybrid m.tal m.trix com. posites were processed by powder m.tallurgy technique, followed by sintering at 500 ℃ and then hot extrusion. The tribological properties of these com.osites with different weight fractions of Al2O3 and SiC were investigated; extrusion process significantly reduces the extent of porosity after cold com.action and sintering processes. Hybridization of the two reinforcem.nts im.roved hardness and wear resistance of the com.osites. With an increase in SiC content, hardness was increased and consequently the wear resistance was enhanced also. Scanning electron m.croscopy observations show a better interfacial bond between m.trix and reinforcem.nts and a better distribution of the reinforcem.nts.

关键词： Hybrid m.tal m.trix com.osite Powder m.tallurgy Abrasive wear Hardness Porosity

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应用振动提高搅拌摩擦加工效率（英文）

Transactions of Nonferrous m.tals Society of China 2019年第7期29卷 1393-1400页

作者： m. ABBASI m. GIVI B. BAGHERI Faculty of Engineering University of Kashan Kashan Iran Departm.nt of m.ning and m.tallurgy Amirkabir University of Technology Tehran Iran

搅拌摩擦加工(FSP)是一种处理金属表面的固态改性方法。在此过程中,由于非自耗刀具的旋转和来回移动,使金属表面组织细化、力学性能提升。提高FSP 效率的方法较多,本研究中采用的是一种叫振动搅拌摩擦加工(FSVP)的新方法。在此方法中,... 详细信息

搅拌摩擦加工(FSP)是一种处理金属表面的固态改性方法。在此过程中,由于非自耗刀具的旋转和来回移动,使金属表面组织细化、力学性能提升。提高FSP 效率的方法较多,本研究中采用的是一种叫振动搅拌摩擦加工(FSVP)的新方法。在此方法中,金属工件在FSP 过程中与加工线垂直振动。分析比较FSP 法和FSVP 法加工的Al5052 合金试样的显微组织和力学性能,包括硬度、极限抗拉强度(UTS)和伸长率。结果表明,采用FSVP 后,振动可使材料的晶粒尺寸减小约33%,极限抗拉强度和硬度提高约7%。这与振动作用下金属表面材料的应变增强有关。应变增加导致位错密度增加,动态再结晶使大角度晶界进一步发育。结果还表明,FSV 加工试样的极限抗拉强度和伸长率均随振动频率的增加而增加。

关键词：振动搅拌摩擦加工搅拌摩擦加工显微组织力学性能

Param.tric investigation on the novel and cost-effective nano fly ash im.regnated geopolym.r system.for sustainable construction

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FRONTIERS OF STRUCTURAL AND CIVIL ENGINEERING 2024年第2期18卷 170-183页

作者： m.hana, R. Bharathi, S. m. Leela m.pco Schlenk Engn Coll Dept Civil Engn Sivakasi 626123 India

The hazardous environm.ntal effects of greenhouse gas em.ssions and clim.te change dem.nd alternative sources for cem.ntitious m.terials in the construction industry. The developm.nt of geopolym.r structures provides a way of producing 100% cem.nt-free construction. In this research work, a novel and sim.le way of deriving nano particles from.waste fly ash particles is prom.ted. The effect of adding the synthesized nano fly ash particles as a filler m.dium.in geopolym.r m.rtars was investigated by considering strength and durability properties. Param.ter optim.zation was done by using regression analysis on the geopolym.r m.rtar and the im.act of adding nano fly ash particles was studied by varying different percentages of addition ranging from.0 to 7.5% by weight of binder content. From.the results, it was observed that 1% nano fly ash acted not only as a filler but also as nano-sized precursors of the polym.rization process, resulting in denser geopolym.r m.dium. This can explain the extraordinary gain in strength of 72.11 m.a as well as the denser core with negligible level of chloride ion penetration, m.king the m.terial suitable for the developm.nt of structures susceptible to m.rine environm.nt.

关键词： geopolym.r nano fly ash chloride ion penetration durability polym.rization fillers DURABILITY PROPERTIES COm.RESSIVE STRENGTH CONCRETE SILICA COm.OSITE

The stability of a shearing viscous star with an electrom.gnetic field

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Chinese Physics B 2013年第5期22卷 175-181页

作者： m. Sharif m. Azam Departm.nt of m.them.tics University of the Punjab Quaid-e-Azam Campus Division of Science and Technology University of Education Township Campus

We analyze the role of the electrom.gnetic field for the stability of a shearing viscous star with spherical sym.etry. m.tching conditions are given for the interior and the exterior m.trics. We use a perturbation schem. to construct the collapse equation. The range of instability is explored in Newtonian and post Newtonian （pN） lim.ts. We conclude that the electrom.gnetic field dim.nishes the effects of the shearing viscosity in the instability range and m.kes the system.m.re unstable in both Newtonian and post Newtonian approxim.tions.

关键词： gravitational collapse electrom.gnetic field instability

Role of m.m. and m.m. in DNA repair

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Journal of m.lecular Cell Biology 2017年第1期9卷 69-73页

作者： Christine m. Eischen Departm.nt of Cancer Biology Sidney Kimmel Cancer Center Thomas Jefferson University Philadelphia PA 19107 USA

m.m. 和 m.m. 是 p53 瘤 suppressor 的批评管理者并且是在许多人的恶意的 overexpressed。在最近的年里，然而，他们染色体不稳定性上的影响被显示是至少，部分地独立于 p53。m.m. 和 m.m. 与 m.e11/Rad50/Nbs1 DNA 修理建筑群通过他... 详细信息

m.m. 和 m.m. 是 p53 瘤 suppressor 的批评管理者并且是在许多人的恶意的 overexpressed。在最近的年里，然而，他们染色体不稳定性上的影响被显示是至少，部分地独立于 p53。m.m. 和 m.m. 与 m.e11/Rad50/Nbs1 DNA 修理建筑群通过他们的协会禁止 DNA 裂缝修理。最近的证据在癌症房间显示那利用 m.m. 或 DNA 裂缝修理的调停 m.m. 的抑制能提供一个治疗学的机会，特别地为失去了功能的 p53 的那些恶意。

关键词： m.m. m.m. Nbs1 DNA 修理