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Thermomecha.ical Analysis of (Cu_(0.5)Tl_(0.5))-1223 Substituted by Pr and La

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Journal of Materials Science & Technology 2012年第2期28卷 169-176页

作者： a.i.Abou Aly R.Awad i.h.ibra.im M.kamal M.Anas Physics Department Faculty of ScienceAlexandria University Physics Department Faculty of ScienceMansoura University

The thermomecha.ical analysis （TMA） of Cu0.5T10.5ba2Ca2-xRxCu30110-δ, where R=Pr and La, with 0.0〈x〈0.15, was carried out in temperature range from 450 to 1145 K. The samples were prepared by singlestep solid state reaction technique. The prepared samples were characterized by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The superconductivity of the prepared samples was investigated by electrical resistivity measurement. The results showed that low substitution content enhanced the （Cu0.5Tlo.5）- 1223 phase forma.ion, while the higher substitution content degraded this phase. The higher superconducting transition temperatures Tc were found to be 114 K and 109 K at x= 0.025 for Pr- and La-substitutions, respectively. The average linear thermal expansion coefficient increased as x increased, while the shrinkage temperature decreased as x increased. Those results were empha.ized by porosity and Vickers microhardness calcula.ions. Debye temperature 0D was calculated from the linear thermal expansion coefficient data and correlated to Tc to estimate the electron-phonon coupling λep.

关键词： (Cu0.5Tl0.5)-1223 Thermomecha.ical analysis Thermal expansion coefficient Debye temperature

Electrical and mecha.ical properties of (Bi, Pb)-2223 substituted by holmium

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Journal of Advanced Cera.ics 2016年第1期5卷 54-69页

作者： W.ABDEEN S.MARAhba R.AWAD a.i.ABOU ALY i.h.iBRa.iM M.MATAR Superconductivity and Metallic Glass Lab Physics Department Faculty of ScienceAlexandria University Alexandria EgyptPhysics Department University College at Al-Gamom Umm Al-Qura University Saudi Arabia Physics Department Faculty of Science Beirut Arab University(BA U) Beirut Lebanon Superconductivity and Metallic Glass Lab Physics Department Faculty of ScienceAlexandria University Alexandria Egypt

The effect of the partial substitution of Ca2+ by ho3+ ions on the electrical and mecha.ical properties of the superconducting phase (Bi,Pb)-2223 was studied. Superconducting samples of the type (Bi1.8Pb0.4)Sr2Ca2.1−x ho x Cu3.1O10+δ were prepared by solid-state reaction technique under ambient pressure, and characterized by means of X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The superconducting transition temperature T c and pseudogap temperature T* were estimated from electrical resistivity measurements, while the critical current density J c was determined from i–V curves. The electrical resistivity data were discussed according to bipolaron model in the absence of thermally excited individual polarons. The sample with x = 0.025 showed the highest phase volume fraction, T c, and J c. Room temperature Vickers microhardness measurements were carried out at different applied loads (0.25–5 N) in order to investigate the performance of the mecha.ical properties of (Bi1.8Pb0.4)Sr2Ca2.1−x ho x Cu3.1O10+δ phase. it was found that all the samples exhibit normal indenta.ion size effect (iSE). The Vickers microhardness number h V increased as x increased from 0 to 0.025. The experimental results were discussed in view of Meyer’s law, hays–Kendall (hK) approach, elastic/plastic deforma.ion (EPD) model, and proportional specimen resistance (PSR) model. The load independent (true) microhardness of (Bi1.8Pb0.4)Sr2Ca2.1−x ho x Cu3.1O10+δ superconducting samples showed identical beha.ior to that of the PSR model.

关键词： (Bi,Pb)-2223 phase ho substitution Vickers microhardness bipolaron model pesudogap temperature

Studies on Progressive Reactions Lea.ing Forma.ions of Different Types of Ba.ium Ferrites

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Journal of Materials Science & Technology 1999年第2期15卷 159-163页

作者： h.i.Saleh(inorga.ic Chemistry Department, Na.ional Research Centre, Dokki-12311, Cairo, Egypt) inorga.ic Chemistry Department National Research Centre Dokki-12311 Cairo Egypt

The present investiga.ion is concerned with the reaction of ba.ium and iron nitrates mixtures using three different molar ra.ios, 1:1 (Ⅰ), 1:2 (Ⅱ) and 2:1 (Ⅲ) at different temperatures as pointed out from the DTA data. The reaction products exhibit 12 compounds namely, ba(NO3)2, αFe2O3, Fe3O4, baFeO3, baFeO2.9, hexagonal baFeO3-x, tetragonal baFeO3-x, baFe2O4, αbaFe2O4, ba2Fe6O11, ba5Fe14O26 and baFe12O19. The forma.ion of these products depend on the molar ra.io between the reactants and the reaction temperature. The reaction products were studied by DTA and TG techniques and characterized by X-ray diffraction patterns, magnetic susceptibility data and scanning electron microscopy, SEM.

关键词： ba Studies on Progressive Reactions Lea.ing Forma.ions of Different Types of Ba.ium Ferrites OO

Tectonics induced switching of provenance during the Late Quaternary aggrada.ion of the indus River Valley, Ladakh, india

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Geoscience Frontiers 2019年第1期10卷 285-297页

作者： Ra.ish Lal h.S.Saini N.C.Pant S.a.i.Mujtaba Department of Geology University of Delhi Geological Survey of india

The indus River flows through Ladakh, one of the driest and coldest places on earth, in a tectonically active domain. Fluvial, gla.iofluvial, lacustrine and debris dominated sequences represent the Late Quaternary sedimentary record along the river course. karakoram Fault, a major crustal scaled feature reported to be active during the Quaternary, is associated with the indus River drainage. Linkages between a major, active fault and deposits formed during the activity period of the fault are explored using heavy mineral deduced provenance and Optically Stimulated Luminescence(OSL) *** deposits in a ~200 km long stretch of the indus River have been exa.ined for a ~80 ka period to decipher the climate linked aggrada.ion history. Damming of the indus River at ~79 ka and existence of the Spituk Lake for >30 ka.is demonstrated. Using geology of the provenance in rela.ion to the mineralogical attributes of the Quaternary deposits, the major drainage reorga.iza.ion when the connection of the Tangtse Valley to the indus was blocked, is inferred at ~73 ka. it is supported by the geologicalgeomorphological evidence. The study demonstrates the applica.ion of provenance linked mineralogy in terrestrial aggrada.ion in a tectonically active region.

关键词： karakoram Fault indus Drainage reorga.iza.ion heavy minerals Aggrada.ion

interaction between protokimberlite melts and mantle lithosphere:Evidence from mantle xenoliths from the Dalnyaya kimberlite pipe,Yakutia(Russia)

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Geoscience Frontiers 2017年第4期8卷 693-710页

作者： i.V.Ashchepkov T.Ntaflos Z.V.Spetsius R.F.Sa.ikhov h.Downes institute of Geology and Mineralogy SD RAS Vienna University Alrosa Stock Company Department of Earth and Planetary Sciences Birkbeck University of London

The Dalnyaya kimberlite pipe（Yakutia,Russia） contains mantle peridotite xenoliths（mostly iherzolites and harzburgites） that show both sheared porphyroclastic（deformed） and coarse granular textures,together with ilmenite and clinopyroxene *** peridotites contain high-temperature Fe-rich clinopyroxenes,sometimes associated with picroilmenites,which are products of interaction of the lithospheric mantle with protokimberlite related *** orthopyroxene-derived geotherm for the lithospheric mantle beneath Dalnyaya.is stepped similar to that beneath the Udachnaya *** granular xenoliths fall on a geotherm of 35 mWm-2 whereas deformed va.ieties yield a 45 mWm-2）geotherm in the 2-7.5 GPa pressure *** chemistry of the constituent minerals including garnet,olivine and clinopyroxene shows trends of increa.ing Fe~#（=Fe/（Fe＋Mg））with decrea.ing *** may suggest that the interaction with fractiona.ing protokimberlite melts occurred at different *** major mantle lithologies are distinguished by the trace element patterns of their constituent minerals,determined by ***,some clinopyroxenes and rare garnets are depleted in ba,Sr,hFSE and MREE and represent relic lithospheric ***-fertilized garnet and clinopyroxene are more *** distribution of trace elements between garnet and clinopyroxene shows that the garnets dissolved primary orthopyroxene and *** high temperature clinopyroxenes related to the protokimberlite melts partially dissolved these *** show decreases in Ni and increases in Al,Ca and Ti from Mg-rich va.ieties to the more Fe-rich,deformed and refertilized *** showing higher Fe~#（0.11-0.15） are found within intergrowths of low-Cr ilmenite-clinopyroxene-garnet related to the crystalliza.ion of protokimberlite melts in feeder *** P-f（O_2） diagrams,garnets and Cr-rich clinopyroxenes indicate reduced conditions at the base of the lithosphere at-5

关键词： Mantle xenoliths Trace element Melt interaction Kimberlite Pyrope Cr-diopside

Three-dimensional analysis of a faulted CO2 reservoir using an Eshelby-Mori-Tanaka approach to rock elastic properties and fault permea.ility

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Journal of Rock Mecha.ics and Geotechnical Engineering 2016年第6期8卷 828-845页

作者： ba Nghiep Nguyen Zhangshuan hou George V.Last Diana h.bacon Pa.ific Northwest Na.ional Laboratory RichlandWAUSA

This work develops a three-dimensional(3D) multiscale model to analyze a complex carbon dioxide(CO_2) faulted reservoir that includes some key geologic features of the San Andreas and nearby faults southwest of the Kimberlina *** model uses the STOMP-CO2 code for flow modeling that is coupled to the AbaQUS~ finite element package for geomecha.ical analysis.A 3D AbaQUS~ finite element model is developed that contains a large number of 3D solid elements with two nearly parallel faults whose damage zones and cores are discretized using the same continuum *** zones with different mineral compositions are considered:shale,sandstone,fault damaged sandstone,fault damaged shale,and fault ***' elastic properties that govern their poroelastic beha.ior are modeled by an Eshelby-Mori-Tanaka approach(EMTA).which can account for up to 15 mineral *** permea.ility of fault damage zones affected by crack density and orienta.ions is also predicted by an EMTA formula.ion.A STOMP-CO2 grid that exactly maps the AbaQUS~ finite element model is built for coupled hydromecha.ical *** of the reservoir assuming three different crack pattern situa.ions(including crack volume fraction and orienta.ion) for the fault damage zones are performed to predict the potential leakage of CO_2 due to cracks that enhance the permea.ility of the fault damage *** results illustrate the important effect of the crack orienta.ion on fault permea.ility that can lead to substantial leakage along the fault attained by the expansion of the CO_2 *** hydraulic fracture and tendency for the faults to slip are also exa.ined and discussed in terms of stress distributions and geomecha.ical properties.

关键词： Carbon dioxide(CO_2) reservoir Geomecha.ical modeling Mineralogy homogeniza.ion Fault Leakage Slip Elastic properties

The Dura.ility of Epoxy Resin Coa.ing

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Journal of Wuhan University of Technology(Materials Science) 2008年第2期23卷 242-244页

作者： ZhAO Fujun ba hengjing GAO Xiaojian School of Civil Engineering Harbin Institute of Technology Harbin 150090 China Da.ing Oilfield Construction Group Daqing 163453 China

The dura.ility of epoxy resin coa.ing was studied under environments with rela.ive humidity （Rh） of 98%-100%, at 55 ℃ for 900 h, at 65 ℃ for 700 h and at 75 ℃ for 400 h, respectively. Peel strength test, dyna.ical mecha.ical thermal analysis （DMTA）, infrared spectroscopy （iR） and energy dispersive X-ray spectroscopy （EDX） were employed for measurements. Peel strength indicated the development of adhesive property of the coa.ing, DMTa.indicated the development of physical property, iR revealed the development of chemical structure, and EDX showed surface element change of the coa.ing. All these results show a good time- temperature equivalence characteristic between humidity a.ing time and temperature.

关键词： epoxy resin coa.ing dura.ility time-temperature equivalence

influence of Solid Fraction on Gra.ity Segrega.ion of Sn in A1-20Sn Alloy Casting

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Journal of Materials Science & Technology 2000年第6期16卷 577-580页

作者： Zhang, P. Du, Y.h. Zeng, D.B. Cui, J.Z. ba, L.M. Dep. of Mecha.ical Eng. Tsinghua Univ. Beijing 100084 China

The influence of solid fraction of Al-20Sn alloy mushy on gra.ity segrega.ion of Sn in casting was studied . The rela.ionship between solid fraction and the temperature of alloy mushy and that between solid fraction of alloy mushy and size of Sn particle in ingot were determined. The results show that the rela.ionship between solid fraction and the temperature of alloy mushy was fs=1683-4.86t+0.003 5t2. The extent of gra.ity segrega.ion of Sn in casting reduced gradually with the increase of solid fraction of alloy mushy. When solid fraction of alloy mushy was larger than 40%, the gra.ity segrega.ion of Sn in casting could be removed ba.ically, and the rela.ionship between solid fraction of alloy mushy and size of Sn particle in ingot was s=-0.64fs+70.8.

关键词： Metal casting

Zeolite usage as source of silica to produce cordierite in MgO–Al_2O_3–SiO_2 system

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Journal of Advanced Cera.ics 2018年第4期7卷 370-379页

作者： Tu?ba Tun? PARLAK A.?ükran DEMiRKiRAN Department of Metallurgical and Materials Engineering Faculty of EngineeringSakarya UniversityEsentepe Campus

in this study, natural zeolite was used as source of silica to produce cordierite. MgO and Al_2O_3 were added to zeolite to obtain the cordierite stoichiometry. Mixture of these raw materials was mecha.ically activated for different dura.ions. The mecha.ically activated powder mixture was characterized using XRD, DSC, SEM, specific surface area, and particle size analyzer. The pycnometer method was used to measure the densities of mecha.ically activated powder mixtures. Mecha.ically activated for 60 min powder mixture was sintered at 1150–1350 ℃ for 1 h. The sintering beha.ior of the samples was determined by measuring the linear shrinkage, density, and apparent porosity. The phases in the sintered samples were identified by XRD. Cordierite and spinel phases were detected for sintered at a temperature higher than 1150 ℃ but corundum accompa.ied to cordierite and spinel at 1150 ℃. The microstructure of the samples was exa.ined using both SEM and AFM. The sintering beha.ior and microstructural properties of the samples changed with an increase in the sintering temperature. As the apparent porosity increased with increa.ing sintering temperature, linear shrinkage and density values decreased. Density values were determined as 2.31–2.69 g/cm^3 depending on the temperature. The grains coarsened at higher temperature and the average grain size depending on the temperature was 1.34–1.96 μm. From the results optimum sintering temperature was determined as 1250 ℃. Dense material was produced at a temperature as low as 1250 ℃ using zeolite as raw material.

关键词： mecha.ical activa.ion sintering zeolite cordierite