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Effects of Thermomagnetic Treatment on Microstructure and Mechanical Properties of Rolling Bearing Steel

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Journal of iron and Steel Research international 2010年第9期17卷 46-52页

作者： constantin Gheorghies ioan i Stefanescu Faculty of Science Low Danube University of Galati Faculty of Mechanics Low Danube University of Galati

The influence of the thermomagnetic treatment on metallurgical and mechanical properties of the rolling bearing steel was investigated. The heating and/or cooling and tempering processes of the samples occurred in a magnetic field having certain strengths. The X-ray diffraction （XRD） patterns of the rolling bearing （RUL 1） steel samples exhibited a beneficial effect of the magnetic field on the structure, phase transformation, and tension state. An increased fatigue reliability was found for the rolling tribomodel made from thermomagnetically treated steel.

关键词： steel thermomagnetic treatment strueture phase transformation tribomodel reliability

Nonlocal Nonlinear Advection-Diffusion Equations

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Chinese Annals of Mathematics,Series B 2017年第1期38卷 281-292页

作者： Peter constantin Department of Mathematics Princeton UniversityPrincetonNJ 08544USA.

The author reviews some results about nonlocal advection-diffusion equations based on lower bounds for the fractional Laplacian.

关键词： Nonlocal Advection Diffusion Fractional Laplacian

Quaternary Neotectonic Configuration of the Southwestern Peloponnese, Greece, Based on Luminescence Ages of Marine Terraces

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Journal of Earth Science 2013年第3期24卷 410-427页

作者： constantin Athanassas ioannis Fountoulis Laboratory of Archaeometry Institute of Materials Science N.C.S.R.'Demokritos' Department of Dynamic Tectonic and Applied Geology Faculty of Geology and Geoenvironment National and Kapodistrian University of Athens

This project studies marine terraces in western Messenia, southwestern Peloponnese, Greece, to propose a model of neotectonic configuration and paleogeographic evolution of western Messenia during the Quaternary. GiS analysis of topographic data and geological mapping revealed flanks of raised terraces created on Quaternary marine deposits. Luminescence ages of sediments from the three westernmost marine terraces tend to be consistent OiS-5, OiS-7 and OiS-9, respectively, thus agreeing with the three latest warm stages of the Pleistocene. Moreover, the type and the extent of deformation of the dated marine terraces allowed us to reflect on the neotectonic configuration of western Messenia as well as to conclude that progressive differential uplift over the last 300 ka has induced a dome-like structure to the upper crust of western Messenia.

关键词： Quaternary Southwest Greece neotectonics sea-level change marine terrace lumines- cence dating tectonic uplift.

Evolution of Texture in Grain Oriented Silicon Steels

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Journal of iron and Steel Research international 2009年第4期16卷 78-83页

作者： constantin Gheorghies Ana Doniga Faculty of Science Dunarea de Jos University of Galati Faculty of Metallurgy and Materials Science Dunarea de Jos University of Galati

Goss texture or （110）[100] crystallographic orientation of the grains is typical grain structure of grain oriented silicon steel used for transformer. This type of texture is one of the most important parameters determining the magnetic properties of the laminated steel plates. The furination and growth of Goss texture in three steel samples are investigated. Two of them are prepared under laboratory conditions and one under industrial conditions. The em- phasis is put on the effects of hot lamination temperature and time, primary and secondary recrystallization temperatures during cold lamination on developing of the Goss texture in correlation with other texture components. Also in all steel processing stages, the influence of the chemical composition on the occurrence of Goss texture is examined.

关键词： silicon steel Goss texture hot rolling process recrystallization annealing temperature

Structure and heat capacity of the NaCeF_4 compound

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Journal of Rare Earths 2013年第9期31卷 911-915页

作者： Virgil constantin Ana-Maria Popescu "ilie Murgulescu" institute of Physical Chemistry of the Romanian Academy Splaiul Independentei 202 st.060021BucharestRomania

This work continued our general research program on obtaining metallic cerium by electrodeposition from NaCeF4 dis-solved in different molten fluorides. The structure of NaCeF4 （cubic or hexagonal depending on the way of preparation） was estab-lished by DTA analysis, iR spectra and X-ray diffraction. The heat capacity （Cp） of NaCeF4 was measured by differential scanning calorimetry in the temperature range of 300-1093 K using the“step-method”. The Cp was fitted by an equation with a satisfactory re-sult. Heat capacity was compared with that calculated from the Neumann-Kopp rule （NKR） and the deviations observed were consis-tent with the stability of the NaCeF4 compound.

关键词： cerium compounds structure heat capacity NaCeF4 rare earths

Unsteady flow of viscoelastic fluid between two cylinders using fractional Maxwell model

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Acta Mechanica Sinica 2012年第2期28卷 274-280页

作者： Muhammad Jamil constantin Fetecau Corina Fetecau Abdus Salam School of Mathematical Sciences GC UniversityLahorePakistan Department of Mathematics NED University of Engineering&TechnologyKarachi-75270Pakistan Department of Mathematics Technical University of IasiIasi-700050Romania Department of Theoretical Mechanics Technical University of IasiIasi-700050Romania

The unsteady flow of an incompressible fractional Maxwell fluid between two infinite coaxial cylinders is studied by means of integral transforms. The motion of the fluid is due to the inner cylinder that applies a time dependent tor- sional shear to the fluid. The exact solutions for velocity and shear stress are presented in series form in terms of some generalized functions. They can easily be particularized to give similar solutions for Maxwell and Newtonian fluids. Fi- nally, the influence of pertinent parameters on the fluid motion, as well as a comparison between models, is highlighted by graphical illustrations.

关键词： Maxwell fluid Fractional derivative Exact so- lutions Velocity field Shear stress Laplace and Hankel transforms

Current Efficiency, Corrosion and Structural Changes in SnO2-Sb2O3-CuO inert Anodes for Aluminium Electrolysis

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Chinese Journal of Chemical Physics 2014年第3期27卷 368-372页

作者： Ana-Maria Popescu Virgil constantin ilie Mur&ulescu institute of Physical Chemistry of the Romanian Academy Splaiul Independentei 202060021 Bucharest Romania

A systematic study was conducted on current efficiency （CE）, corrosion and structural changes in SnO2-based inert anodes （made of 96wt%SnO2＋2wt%Sb2O3＋2wt%CuO） on a laboratory Hall-Heroult aluminium cell. The influence of operating parameters and electrolyte composition on the CE and corrosion process were evaluated. The CE was found to be more than 90% and catastrophic corrosion took place at low percent of Al2O3, high percent of LiF, low cryolite ratio and high current densities. From all the structural changes that took place in the SnO2-based inert anodes, we assumed that the most important contribution was due to the migration of CuO towards the outer limits of the constituent grains of SnO2 based ceramic. The complex process occurred during the formation of various phases and their sintering ability both directly depended on Cu/Sb molar ratio.

关键词： inert anode Aluminium electrowinning Current efficiency

Synthesis, Characterization and Thermophysical Properties of Three Neoteric Solvents-ionic Liquids Based on Choline Chloride

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Chemical Research in Chinese Universities 2014年第1期30卷 119-124页

作者： POPESCU Ana-Maria constantin Virgil Laboratory of Molten Salts llie Murgulescu Institute of Physical Chemistry of the Romanian Academy Bucharest 006021 Romania

The authors prepared,characterized and preliminary studied the properties of some neoteric solvents-ionic liquids based on choline chloride,i.e.,three ionic liquids based on the eutectics of choline chloride（2-hydroxyN,N,N-trimethylethanaminium chloride） with,respectively,urea,malonic acid and citric *** obtained mixtures were clear and colorless ionic liquids at room *** thermophysical properties,namely,density,viscosity,and electrical conductivity of these mixtures were investigated as a function of temperature within a range of 298-353 *** for the temperature dependence of the measured properties were generated and discussed in terms of Arrhenius *** the electrochemical windows of the eutectic liquids were determined.

关键词： Neoteric solvent ionic liquid Choline chloride Malonic acid Citric acid Density Viscosity Conductivity

Towards understanding,estimating and mitigating higher-mode effects for more resilient tall buildings

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Resilient Cities and Structures 2022年第1期1卷 53-64页

作者： constantin Christopoulos Chiyun Zhong Department of Civil and Mineral Engineering University of TorontoTorontoCanada

Rapid urbanization has resulted in increased demand for tall buildings in many large and medium-sized cities around the *** code-based standards for seismic design are primarily aimed at minimizing life-safety risks under major *** reinforced concrete(RC)high-rise buildings designed following current code requirements are expected to achieve collapse-prevention,the contribution of higher modes of vibrations to the dynamic response of these structures can produce seismic demands significantly larger than those obtained from prescriptive code-based procedures,causing unexpectedly higher structural and non-structural damage to these *** imply considerable costs associated with the loss of residences and business operations as well as the post-earthquake recovery of *** paper presents a concise review of the current state-of-the-art and state of research pertaining to the understanding,estimation and mitigation of higher-mode effects on the seismic response of tall and slender RC *** paper is organized into four main foci:(1)analytical studies on understanding and quantifying higher-mode effects,(2)available experimental work on this topic,(3)advances in code practices in accounting for higher-mode effects in seismic design of RC tall buildings,and(4)recent developments in innovative systems intended to mitigate higher-mode effects in RC tall *** paper concludes by briefly summarizing future challenges facing the construction of earthquake-resilient RC tall buildings that are essential in building resilient cities of the future.

关键词： Higher-mode effect Resilience Earthquake Seismic design High-rise building Mitigation Seismic analysis