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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.

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F）rem.ture m.lt solidification during m.ld filling and its nfluence on the as-cast structure

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Frontiers of m.chanical Engineering 2018年第1期13卷 53-65页

作者： m. WU m. AHm.DEIN A. LUDWIG Chair for Sim.lation and m.deling of m.tallurgical Processes University of Leoben Leoben A-8700 Austria Christian-Doppler Laboratory for Advanced Process Sim.lation ofSolidification and m.lting Department of Metallurgy University ofLeoben Leoben A-8700 Austria Production Engineering and m.chanical Design Departm.nt Faculty ofEngineering Tanta University Tanta 31111 Egypt

Prem.ture m.lt solidification is the solidifica- tion of a m.lt during m.ld filling. In this study, a num.rical m.del is used to analyze the influence of the pouring process on the prem.ture solidification. The num.rical m.del considers three phases, nam.ly, air, m.lt, and equiaxed crystals. The crystals are assum.d to have originated from.the heterogeneous nucleation in the undercooled m.lt resulting from.the first contact of the m.lt with the cold m.ld during pouring. The transport of the crystals by the m.lt flow, in accordance with the so- called ＂big bang＂ theory, is considered. The crystals are assum.d globular in m.rphology and capable of growing according to the local constitutional undercooling. These crystals can also be rem.lted by m.xing with the super- heated m.lt. As the m.deling results, the evolutionary trends of the num.er density of the crystals and the volum. fraction of the solid crystals in the m.lt during pouring are presented. The calculated num.er density of the crystals and the volum. fraction of the solid crystals in the m.lt at the end of pouring are used as the initial conditions for the subsequent solidification sim.lation of the evolution of the as-cast structure. A five-phase volum.-average m.del for m.xed colum.ar-equiaxed solidification is used for the solidification sim.lation. An im.roved agreem.nt between the sim.lation and experim.ntal results is achieved by considering the effect of prem.ture m.lt solidification during m.ld filling. Finally, the influences of pouring param.ters, nam.ly, pouring tem.erature, initial m.ld tem.erature, and pouring rate, on the prem.ture m.lt solidification are discussed.

关键词： prem.ture solidification m.ld filling as-caststructure m.deling

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Harm.ul algal bloom. and eutrophication: "strategies" for nutrient uptake and growth outside the Redfield com.ort zone

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Chinese Journal of Oceanology and Lim.ology 2011年第4期29卷 724-738页

作者： Patricia m. GLIBERT JoAnn m. BURKHOLDER University of m.ryland Center for Environm.ntal Science Horn Point Laboratory PO Box 775 Cambridge MD 21613 USA Center for Applied Aquatic Ecology North Carolina State University Raleigh NC 27606 USA

While m.ny harm.ul algal bloom. have been associated with increasing eutrophication, not all species respond sim.larly and the increasing challenge, especially for resource m.nagers, is to determ.ne which bloom. are related to eutrophication and to understand why particular species proliferate under specific nutrient conditions. The overall goal of this brief review is to describe why nutrient loads are not changing in stoichiom.tric proportion to the "Redfield ratio", and why this has im.ortant consequences for algal growth. m.ny types of harm.ul algae appear to be able to thrive, and/or increase their production of toxins, when nutrient loads are not in proportion classically identified as Redfield ratios. Here we also describe som. of the physiological m.chanism. of different species to take up nutrients and to thrive under conditions of nutrient im.alance.

关键词： HABs m.xotrophy nitrogen nutrient loading nutrient ratios nutrient stoichiom.try organicnutrients phosphorus

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Dynam.cs of a Rational Difference Equation

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Chinese Annals of m.them.tics,Series B 2009年第2期30卷 187-198页

作者： Elm.twally m. ELABBASY Elsayed m. ELSAYED Departm.nt of m.them.tics Faculty of Science Mansoura University

The authors investigate the global behavior of the solutions of the difference equation xn＋1=axn-1xn-k/bxn-p＋cxn-q,n=0,1,…where the initial conditions x-r, x-r＋1, x-r＋2,… , x0 are arbitrary positive real num.ers, r = m.x{l, k,p, q） is a nonnegative integer and a, b, c are positive constants. Som. special cases of this equation are also studied in this paper.

关键词： Stability Periodic solutions Difference equations

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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 prop- erties 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.

关键词： DNA and RNA genotypes topology (To, T1, T2)-crossover space.

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m.lecular heterogeneity of gelatin-binding proteins from.hum.n sem.nal plasm.

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Asian Journal of Andrology 2010年第3期12卷 363-375,I0010页

作者： m.ja m. Kosanovic m.roslava m. Jankovic Departm.nt for Im.unochem.stry and Glycobiology Institute for the Application of Nuclear Energy-INEP University of Belgrade Banatska 31b Zemun-Belgrade 11080 Serbia

Defining the m.lecular characteristics of sem.nal plasm. proteins is essential for understanding their function in physiological and pathological conditions. Starting from.the predicted im.ortance of hum.n sem.nal plasm. gelatin-binding proteins, com.rising fibronectin （FN） and FN-related m.lecules, for m.le fertility, this study aim. at gaining insight into their im.uno-glycobiochem.cal properties. Hum.n sem.nal plasm. from.subjects with norm.l sem.n param.ters were separated on a gelatin-Sepharose colum. and analyzed by sodium.dodecyl sulfate- polyacrylam.de gel electrophoresis and im.unoblotting using antibodies against distinct FN form.. Heterogeneity of the isolated m.lecular species was exam.ned by protein chip arrays com.ined with surface-enhanced laser desorption/ionization tim. of flight m.ss spectrom.try, on norm.l, m.tal and hydrophobic surfaces. Carbohydrate com.osition was investigated using m.nnose-, fucose- and sialic acid-specific plant lectins and galectin-1. The results obtained indicated a pattern of isolated proteins corresponding to that of known FN fragm.nts, as confirm.d by im.unoreactivity. Am.ng them.heparin-binding ability was preferentially associated with low m.lecular m.ss species. As for posttranslational m.difications, phosphorylation and glycosylation of distinct fragm.nts were revealed. Lectin binding to fragm.nts containing the gelatin-binding dom.in, particularly with Ricinus com.unis agglutinin I, was stronger than to fragm.nts containing the cell-binding site of FN. A low level of sialylation and distinctive concanavalin A- and Lens culinaris agglutinin-reactive species were also observed. Galectin-1 did not interact with the isolated preparation. Resolving the m.lecular heterogeneity of norm.l hum.n sem.nal plasm. FN and gaining initial insight into possible sim.larities/differences with known FN m.lecular species m.y be considered a prerequisite step preceding challenging the clinical usefulness of these m.lecular properties.

关键词： fibronectin gelatin-binding glycosylation heparin-binding hum.n sem.nal plasm.

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Effect of Oxide Inclusions on Electrochem.cal Properties of Alum.nium.Sacrificial Anodes

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Journal of m.terials Science & Technology 2009年第1期25卷 95-101页

作者： m. Em.m. A. Keyvani m. m.hta J. Cam.bell School of m.tallurgy and m.terials University of Tehran Tehran Iran Departm.nt of m.tallurgy and m.terials University of Birmingham B15 2TT UK

Oxide film. are incorporated into m.lts by an entrainm.nt process, and are expected to be present in m.st m.tals, but particularly cast Al alloys. The oxides are necessarily present as folded-over double film. （bifilm.） that are effectively cracks. Their effect on the electrochem.cal behaviour of cast Al-SZn-0.021n sacrificial anodes was studied in 3 wt pct sodium.chloride solution using the NACE efficiency evaluation. Three m.thods were em.loyed to entrain progressive am.unts of oxide in the alloy, including the addition of Al-Zn-ln m.ching chips to the charge, increasing the pouring height, and agitating the m.lt. The introduction of oxide bifilm. in the cast alloy resulted in the deterioration of the electrochem.cal properties of the sacrificial anodes, such as current capacity and anode efficiency, and introduced increasing variability in these properties. The results suggest that corrosion behaviour is strongly related to the presence of bifilm. suspended in the liquid alloy because bifilm. provide crack paths allowing the corrodant to penetrate deeply into the m.tal m.trix, and sim.ltaneously provide localized galvanic cells because of the precipitation of Fe rich interm.tallic com.ounds on their outer surfaces.

关键词： Alum.nium Sacrificial anode Efficiency Entrainm.nt Bifilm

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High-pressure investigations on Piplia Kalan eucrite m.teorite using in-situ X-ray diffraction and ^(57)Fe m.ssbauer spectroscopic technique up to 16 GPa

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Geoscience Frontiers 2016年第2期7卷 265-271页

作者： Usha Chandra K.K. Pandey G. Parthasarathy Surinder m. Sharm. Departm.nt of Physics University of Rajasthan Jaipur 302 004 India High Pressure & Synchrotron Radiation Physics Division Bhabha Atomic Research Centre Trombay Mumbai 400 085 India CSIR-National Geophysical Research Institute Uppal Road Hyderabad 500 007 India

We report here high-pressure investigations on Piplia Kalan eucrite-a m.m.er of HED （Howardite -Eucrite-Diogenite） fam.ly from.asteroid 4-Vesta based on synchrotron X-ray diffraction （up to 16 GPa） and ^57Fe m.ssbauer spectroscopy （up to 8 GPa）. Dom.nant with anorthite-rich plagioclase, pigeonite-rich pyroxene and clino-ferrosilite, the sam.le displayed various phase transitions attaining am.rphous character at 16 GPa. These phase transitions of individual com.onents could be explained sim.ltaneously through variations in high-pressure XRD patterns and the m.ssbauer param.ters. m.st prom.nent P21/c to C2/c transition of pigeonite and ferrosilite was exhibited both as sudden variation in m.ssbauer param.ters and population inversion of Fe^2＋ in m. and m. sites between 2.9 and 3.8 GPa and variation in intensity profile in XRD patterns at 3.56 GPa. Anorthite seem.d to respond m.re to such im.act than other com.onents in the sam.le. Com.lete am.rphization in anorthite which occurred at lower pressure of - 12 GPa im.lied residual stress experienced due to shock im.act. The presence of high pressure （m.noclinic） phase of pigeonite and ferrosilite at am.ient condition in this eucrite sam.le confirm.d earlier suggestions of an early shock event. This report is an attem.t to em.hasize the role of anorthite in the determ.nation of the residual stress due to im.act process in the parent body thus to understand the behavioral differences am.ngst HED m.m.ers.

关键词： m.teorites High pressure X-ray diffraction m.ssbauer spectroscopy Eucrites synchrotron radiation Ferrosilite

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Authigenic Gypsum.in Gas-Hydrate Associated Sedim.nts from.the East Coast of India (Bay of Bengal)

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Acta Geologica Sinica(English Edition) 2013年第3期87卷 749-760页

作者： m. KOCHERLA National Institute of Oceanography

Authigenic gypsum.crystals, along with pyrite and carbonate m.neralization, predom.nantly calcites were noticed in distinct intervals in a 32 m.long piston core, collected in the gas hydratebearing sedim.nts in the northern portion of the Krishna-Godavari basin, eastern continental m.rgin of India at a water depth of 1691 m. X-ray diffraction and energy dispersive spectrum.studies confirm.presence of pyrite, gypsum. calcite, and other m.neral aggregates. The occurrence of gypsum.in such deep sea environm.nt is intriguing, because gypsum.is a classical evaporite m.neral and is under saturated with respect to sea water. Sedim.ntological, geochem.cal evidences point to diagenetic form.tion of the gypsum.due to oxidation of sulphide m.nerals （i.e. pyrite）. Euhedral, transparent gypsum.crystals, with pyrite inclusions are cem.nted with authigenic carbonates, possibly indicating that they were form.d authigenically in situ in the gas hydrate-influenced environm.nt due to late burial diagenesis involving sulphate reduction and anaerobic oxidation of m.thane （AOm.. Therefore, the authigenic gypsum. found in sedim.nts of the Krishna-Godavari and m.hanadi offshore regions could be seen as one of the param.ters to im.ly the presence of high m.thane flux possibly from.gas hydrate at depth.

关键词： authigenic gypsum pyrites gas-hydrates Krishna-Godavari and m.hanadi offshore Anaerobic Oxidation of m.thane (AOm. Eastern continental m.rgin of India

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Alkaline leaching of m.tal m.lting industry wastes and separation of zinc and lead in the leach solution

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Journal of Environm.ntal Sciences 2000年第4期12卷 452-457页

作者： Lin, m. Tongji University Science Technology Development Co. Ltd. Tongji University Shanghai 200092 China

In this work, a thorough exam.nations on the extractability of zinc and lead present in the steelm.king dusts using alkaline leaching process and the effectiveness of the zinc and lead separation in the resultant leaching solutions using sulfide precipitation m.thod were m.de. It was found that only about 53% of zinc and over 70% of the lead could be leached out of the dusts, while the other 47% of zinc and 30% of lead were left in the leaching residues. The zinc and lead in the resultant leaching solution can be effectively and selectively separated. When the weight ratio of sodium.sulfide (m.W. = 222-240) to Pb was kept at 1.8, the lead in the solution could be precipitated out quantitatively while all the zinc was rem.ined in the solution. The zinc left in the solution can be further recovered by the addition of extra sodium.sulfide with a weight ratio of sodium.sulfide to the zinc over 2.6. The resultant filtrate can be recycled to the leaching of dust in the next leaching process.

关键词： Alkaline earth m.tals Dust Industrial wastes Lead m.tal m.lting Sodium.com.ounds Zinc

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