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Sliding Wear Behavior of a Grey Cast Iron Surface Remelted by TIG

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Journal of Materials Science & Technology 2009年第5期25卷 622-628页

作者： h.Mohamadzadeh h.Saghafian sh.Kheirandish Department of Metallurgy and Materials Engineering Iran University of Science and TechnologyTehranIran

The sliding wear behavior of a grey cast iron surface remelted by tungsten inert gas （TIG） was studied and compared with the unremelted one in the current work. To evaluate the wear behavior a Pin-on-Disk wear test machine was used. Pins which were prepared from the samples with the remelted layers of different thicknesses of 1.2, 1.8, 2.5 and 3 turn were worn on an AISID3 steel counterface having a hardness of 63hRC under the applied loads of 54, 76 and gg N at a constant sliding velocity of 0.45 m/s. Scanning electron microscopy （SEM） equipped with energy dispersive X-ray analysis （EDS） and X-ray diffraction （XRD） techniques were used to characterize worn surface and subsurface and also wear debris obtained from the wear tests under different test conditions. Results showed that surface remelted grey cast iron have better wear properties for all applied normal loads in comparison with unremelted ones. Microscopic studies on the worn surfaces and subsurfaces of samples revealed that dominant wear mechanism for surface remelted samples was mild oxidative, while it was severe for unremelted samples. Increasing remelted layer thickness and then forming grosser microstructure lead to a decline of wear properties, whereas lower thickness of remelted layer with finer microstructure due to having higher cooling rate through remelting process can withstand better against wear.

关键词： Grey cast Iron Surface remelted Tungsten inert gas (TIG) Wear

Dry Sliding Oxidative Wear in Plain Carbon Dual Phase Steel

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Journal of Iron and Steel Research(International) 2007年第4期14卷 43-48页

作者： V Abouei h Saghafian sh Kheirandish Department of Metallurgy and Materials Engineering Iran University of Science and TechnologyNarmak 16844TehranIran

To investigate the tribological potential of the dual phase （DP） steel as a wear resistant material, the wear and the friction characteristics of this steel, which consists of hard martensite islands embedded in a ductile ferrite matrix, have been investigated and compared with those observed in plain carbon hardened （h） steel that has the same carbon content of 0.2%. Dry sliding wear tests have been carried out using a pin-on-disk wear testing machine at different normal loads of 21.3 N, 28. 5 N, 35.7 N, and 42.6 N and at a constant sliding velocity of 1.20 m/s. The analysis of surface and wear debris of samples showed that the wear mechanism was mainly mild oxidative. The friction and the wear rate of the h steel and the DP Steel have been explained with respect to the microstructure and the wear mechanism.

关键词： dual phase steel wear microstructure heat treatment

Evaluation of Four Coals for Blast Furnace Pulverized Coal Injection

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Journal of Iron and Steel Research(International) 2010年第3期17卷 8-12,20页

作者： sh Raygan h Abdizadeh A Eskandari Rizi School of Metallurgy and Materials Engineering University of Tehran

One of the effective methods of reducing coke consumption is pulverized coal injection. The most important problems encountered in this method are reduced permeability, unburned and high ash content. To select the best coal for injection, suitable tests can be used. Therefore, experiments such as proximate and ultimate analysis, Rock- Eval and combustion tests were performed on four kinds of coals from different mines, including Sarakhs, Sangrood, Karmozd, and Tabas. The results of proximate and ultimate analysis indicated that although the sulfur content and ash content of selected coals were a little high, they were suitable for coal injection. The results of combustion experiments and Rock-Eval tests showed that Karmozd coal was the best one to be injected into blast furnace. The result indicated that the mixing of coals could improve the combustion properties of pulverized coals.

关键词： pulverized coal blast furnace non-coking coal

Sorption of certain lanthanides by kieselguhr loaded with Cyanex 572 from sulfate medium

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Journal of Rare Earths 2020年第3期38卷 299-305页

作者： sh.sh.Emam M.S.Gasser N.E.El-hefny W.h.Mahmoud h.F.Aly hot Laboratories Centre Atomic Energy AuthorityCairo 13759Egypt Department of Chemistry Faculty of ScienceAin Shams UniversityCairoEgypt

Kieselguhr for chromatography was loaded with Cyanex 572 extractant and characterized using X-ray diffraction(XRF),scanning electron microscopy(SEM),Fourier transform infra-red(FT-IR),and thermal *** of some heavy lanthanides together with yttrium by the prepared kieselguhr/Cy-572 sorbent was investigated by batch experiment in terms of initial metal ions concentrations,volume to solid mass ratio(V/m),sulfuric acid concentration as well as *** sorption equilibrium of Cy-572 loaded kieselguhr was satisfactorily explained by the pseudo second-order kinetic model and Langmuir isotherm ***,the values of thermodynamic parameters △G°,△h°,and △S°at25℃of the studied metal ions show that the process is spontaneous and endothermic in nature.2.0 mol/L hNO3 is promising to desorb these metal ions.

关键词： Sorption Cyanex 572 Lanthanides Kieselguhr Sulfate medium Rare earths

Effects of Silicon Content and Intercritical Annealing on Manganese Partitioning in Dual Phase Steels

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Journal of Iron and Steel Research(International) 2010年第5期17卷 44-50页

作者： A Nouri h Saghafian sh Kheirandish Department of Metallurgy and Materials Engineering Iran University of Science and Technology

Steels of constant manganese and carbon contents with silicon content of 0.34 %- 2.26% were cast. The as-cast steels were then hot rolled at 1 100 ℃ in five passes to reduce the cast ingot thickness from 80 to 4 mm, air cooled to room temperature and cold rolled to 2 mm in thickness. Dual phase microstructures with different volume fraction of martensite were obtained through the intercritical annealing of the steels at different temperatures for 15 min followed by water quenching. In addition to intercritical annealing temperature, silicon content also altered the volume fraction of martensite in dual phase steels. The partitioning of manganese in dual phase silicon steels was investigated using energy-dispersive spectrometer （EDS）. The partitioning coefficient, defined as the ratio of the amounts of alloying element in the austenite to that in the adjacent ferrite, for manganese increased with increasing intercritieal annealing temperature and silicon content of steels. It was also found that the solubility of manganese in ferrite and austenite decreased with increasing intereritical temperature. The results were discussed by the diffusivity and the solubility of manganese in ferrite and austenite existed in dual phase silicon steels.

关键词： partitioning dual phase steel intercritical annealing temperature silicon manganese

Comparative studies on Y(Ⅲ)and Dy(Ⅲ)extraction from hydrochloric and nitric acids by Cyanex 572 as a novel extractant

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Journal of Rare Earths 2018年第12期36卷 1342-1350页

作者： N.E.El-hefny M.S.Gasser sh.sh.Emam W.h.Mahmoud h.F.Aly hot Laboratories Centre Atomic Energy Authority Faculty of Science Ain Shams University

Extraction of Y(III) and Dy(III) from hydrochloric and nitric acids by Cy-572 in kerosene was studied. The factors affecting the extraction were separately investigated. The stoichiometry of the extracted species was deduced on the basis of slope analysis method. Evaluation of extraction equilibrium and stripping investigation was studied as well as saponification effect of Cy-572. The composition of the extracted metal species in the organic phase was found to be [MA·(hA)] for Y(III) or Dy(III) in both media.1.0 mol/L hCI is the best stripping agent for each metal ion from the studied acidic media in one *** Cy-572 does not exhibit any selectivity towards the extraction of Y(III) or Dy(III) from both hCI and hNOsolutions. Based on the obtained results, the data were compared and the separation feasibility between lanthanides and Y(III) in the two media was discussed.

关键词： Extraction Cyanex-572 Yttrium Lanthanides Separation factor Saponification

Monoenergetic electron parameters in a spheroid bubble model

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Chinese Physics B 2013年第2期22卷 347-351页

作者： h.Sattarian sh.Rahmatallahpur T.Tohidi Maraghe Branch Physics DepartmentIslamic Azad UniversityMaraghehIran Bonab Branch Physics DepartmentIslamic Azad UniversityBonabIran Department of Physics Azarbaijan University of Tarbiat MoallemTabrizIran

A reliable analytical expression for the potential of plasma waves with phase velocities near the speed of light is *** presented spheroid cavity model is more consistent than the previous spherical and ellipsoidal models and it explains the mono-energetic electron trajectory more accurately,especially at the relativistic *** maximum energy of electrons is calculated and it is shown that the maximum energy of the spheroid model is less than that of the spherical *** electron energy spectrum is also calculated and it is found that the energy distribution ratio of electrons △E/E for the spheroid model under the conditions reported here is half that of the spherical model and it is in good agreement with the experimental value in the same *** a result,the quasi-mono-energetic electron output beam interacting with the laser plasma can be more appropriately described with this model.

关键词： quasi-mono-energetic electron bunches intense laser plasma accelerator laser wake field bubble regime

Inverse heat Transfer Problem of Thermal Contact Conductance Estimation in Periodically Contacting Surfaces

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Journal of Thermal Science 2009年第2期18卷 150-159页

作者： M.h.shojaeefard K.Goudarzi M.sh.Mazidi Dept. of Mechanical Engineering Iran University of Science and Technology

The problems involving periodic contacting surfaces have different practical applications. An inverse heat conductionproblem for estimating the periodic Thermal Contact Conductance (TCC) between one-dimensional, constantproperty contacting solids has been investigated with conjugate gradient method (CGM) of function *** method converges very rapidly and is not so sensitive to the measurement errors. The advantage of thepresent method is that no a priori information is needed on the variation of the unknown quantities, since the solutionautomatically determines the functional form over the specified domain. A simple, straight forward techniqueis utilized to solve the direct, sensitivity and adjoint problems, in order to overcome the difficulties associatedwith numerical methods. Two general classes of results, the results obtained by applying inexact simulatedmeasured data and the results obtained by using data taken from an actual experiment are presented. In addition,extrapolation method is applied to obtain actual results. Generally, the present method effectively improves theexact TCC when exact and inexact simulated measurements input to the analysis. Furthermore, the results obtainedwith CGM and the extrapolation results are in agreement and the little deviations can be negligible.

关键词：热接触逆问题共轭梯度周期性

右美托咪定复合舒芬太尼自控静脉镇痛对阴式子宫切除术患者术后应激指标及疼痛状态的影响

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全科医学临床与教育 2024年第7期22卷 611-615页

作者：叶玉萍陶振云刘双庆季敏鹏南昌大学附属口腔医院麻醉科江西南昌330006 义乌市中心医院麻醉科

目的分析右美托咪定复合舒芬太尼自控静脉镇痛对阴式子宫切除术患者术后应激及疼痛状态的影响。方法选择102例阴式子宫切除术患者为研究对象,随机分为联合组(给予右美托咪定复合舒芬太尼自控镇痛)和对照组(给予舒芬太尼自控镇痛)各51例... 详细信息

目的分析右美托咪定复合舒芬太尼自控静脉镇痛对阴式子宫切除术患者术后应激及疼痛状态的影响。方法选择102例阴式子宫切除术患者为研究对象,随机分为联合组(给予右美托咪定复合舒芬太尼自控镇痛)和对照组(给予舒芬太尼自控镇痛)各51例。比较两组术毕(T_(0))、术后2 h(T_(1))、术后6 h(T_(2))、术后12 h(T_(3))、术后24 h(T_(4))的血流动力学指标[心率(hR)、氧饱和度(SpO2)、平均动脉压(MAP)]、自控静脉镇痛(PCIA)次数、应激反应指标[促肾上腺皮质激素(ACTh)、皮质醇(Cor)、醛固酮(ALD)、白介素-6(IL-6)],T_(0)、T_(4)时段的疼痛因子[β内啡肽(β-EP)、血清P物质(SP)、神经肽Y(NPY)]水平、视觉模拟评分(VAS)以及不良反应。结果T_(2)时,联合组hR和MAP低于对照组(t分别=2.27、6.05,P均hR高于对照组,MAP低于对照组(t分别=-2.22、-4.90;2.78、2.55,P均h、Cor、ALD水平均低于对照组(t分别=21.75、38.55、41.42;41.91、2.12、2.60、5.80;5.75,4.26、5.91、7.51、20.01,P均0.05)。结论右美托咪定复合舒芬太尼自控静脉镇痛有利于改善阴式子宫切除术患者术后应激指标和稳定血流动力学指标,迅速有效地缓解疼痛,且不良反应发生风险较低。

关键词：右美托咪定舒芬太尼自控静脉镇痛阴式子宫切除术术后应激疼痛