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Transactions of Nonferrous Metals Society of China 2024年

作者： Mohsen rastegari Masoud ATAPOUR Aboozar TAHERIZADEH Amin HAKIMIZAD Maryam RAHMATI Department of Materials Engineering， Isfahan University of Technology Yekta Mobaddel Pars Co.， Science and Technology Campus， Yazd University Dental Materials Research Center， Dental Research Institute， School of Dentistry， Isfahan University of Medical Sciences

Al-Mg laminated macro composites （LMC） have garnered attention due to their excellent mechanical properties and low density. However， their weak corrosion resistance has limited their industrial applications. Plasma electrolytic oxidation （PEO） has been explored as a potential solution to this issue by producing hard and thick oxide coatings on the surface of Al-Mg LMCs manufactured through hot extrusion bonding. In this study， PEO coatings were prepared on Al-Mg LMCs using both unipolar and bipolar waveforms in an appropriate electrolyte for both aluminum and magnesium alloys. The techniques of FESEM/EDX， GIXRD， and electrochemical methods of Potentiodynamic polarization and EIS were carried out. The results revealed that the coatings produced using the bipolar waveform exhibited lower porosity and higher thickness than those produced using the unipolar one. The corrosion performance of the specimens' cut edge was investigated using electrochemical impedance spectroscopy （EIS） after 1， 8， and 12 hours of immersion in a 3.5%wt. NaCl solution. It was observed that the coating produced using the bipolar waveform demonstrated the highest corrosion resistance after 12 hours of immersion， with an estimated corrosion resistance of 41.87 kΩ.cm2， which was approximately three times higher than that of the unipolar coating. Notably， no signs of galvanic corrosion were observed in the LMC， and only minor corrosion attacks were observed on the magnesium layer in some areas.

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Fabrication of plain carbon steel/high chromium white cast iron bimetal by a liquid–solid composite casting process

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International Journal of Minerals,Metallurgy and Materials 2015年第9期22卷 950-955页

作者： V.Javaheri H.rastegari M.Naseri Division of Research and Development Isfahan Casting Industries Co.(ICI) Department of Engineering Birjand University of Technology

High-chromium white cast iron （HCWCI） is one of the most widely used engineering materials in the mining and cement industries. However, in some components, such as the pulverizer plates of ash mills, the poor machinability of HCWCI creates difficulties. The bimetal casting technique is a suitable method for improving the machinability of HCWCI by joining an easily machined layer of plain carbon steel （PCS） to its hard part. In this study, the possibility of PCS/HCWCI bimetal casting was investigated using sand casting. The investigation was conducted by optical and electron microscopy and non-destructive, impact toughness, and tensile tests. The hardness and chemical composition profiles on both sides of the interface were plotted in this study. The results indicated that a conventional and low-cost casting technique could be a reliable method for producing PCSYdCWCI bimetal. The interfacial microstructure comprised two distinct lay- ers： a very fine, partially spheroidized pearlite layer and a coarse full pearlite layer. Moreover, characterization of the microstructure revealed that the interface was free of defects.

关键词： bimetals carbon steel cast iron casting interfaces microstructure mechanical properties

Coarsening Kinetics of γ' Precipitates in Dendritic Regions of a Ni_3 Al Base Alloy

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Journal of Materials Science & Technology 2012年第3期28卷 221-228页

作者： H.B.Motejadded M.Soltanieh S.rastegari School of Metallurgy and Materials Engineering Iran University of Science and TechnologyTehranIran

Coarsening behavior of γ＇ precipitates in the dendritic regions of a Ni 3 Al base alloy containing chromium,molybdenum,zirconium and boron was *** treatment was performed up to 50 h at 900,1000 and 1100℃.The alloy was produced by vacuum-arc remelting *** show that coarsening of the γ＇ precipitates in this complex alloy containing high volume fractions of γ＇ phase follows Lifshitz-Slyozov-Wagner（LSW） *** activation energy of the γ＇ precipitates was evaluated to be about 253.5 ***-1 which shows that the growth phenomenon is controlled by volume diffusion of *** an innovative approach,diffusion coefficient of the solute element（s） and the interfacial energy between γ＇ precipitates and γ＇（matrix） were estimated at 900,1000 and 1100℃.Accordingly,the interfacial energies at 900,1000 and 1100℃ are 4.49±1.48,2.08±0.69 and 0.98±0.32 mJ.m-2,*** the diffusivities of solute element（s） at these temperatures are 3.41±1.08,30±9.5 and 145.15±45.85（10-15 m-2.s-1）,respectively.

关键词： Ni3 Al base intermetallic Coarsening kinetics Activation energy

Dissolution Mechanism of a Zr Rich Structure in a Ni_3Al Base Alloy

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Journal of Materials Science & Technology 2011年第10期27卷 885-892页

作者： H.B.Motejadded M.Soltanieh S.rastegari School of Materials Science and Engineering Iran University of Science and Technology

In the present research, the dissolution mechanism of a Zr rich structure during annealing of a Ni3Al base alloy containing Cr, Mo, Zr and B, was investigated. The annealing treatments were performed up to 50 h at 900, 1000 and 1100℃. The alloy used in this investigation was produced by vacuum-arc remelting technique. The results show that at the beginning of the process, a mixed interface reaction and local equilibrium （long range diffusion） mechanism controls the dissolution process. After a short time, this mechanism changes and the dissolution mechanism of the Zr rich structure changes to only long range diffusion of Zr element. According to this mechanism, the activation energy of this process is estimated to be about 143.3 ***-1. Also the phases that contribute to this structure and the transformations that occur at the final steps of solidification of this alloy were introduced. According to the results, at the final step of solidification, a peritectic type reaction occurs in the form of L＋ y→Ni7Zr2 and →-Ni7Zr2 segregates from the melt. Following this transformation, →-Ni7Zr2 eutectic separates from the remaining Zr rich liquid. The solidification process will be terminated by a ternary eutectic reaction in the form of L→y＋Ni5Zr＋Ni7Zr2.

关键词： Ni3Al base alloy Microstructure Dissolution kinetics Activation energy

Applying gravitational search algorithm in the QoS-based Web service selection problem

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Journal of Zhejiang University-Science C(Computers and Electronics) 2011年第9期12卷 730-742页

作者： Bahareh ZIBANEZHAD Kamran ZAMANIFAR Razieh Sadat SADJADY Yousef rastegari Computer Engineering Department Islamic Azad UniversityNajafabad BranchIsfahanIran Electrical and Computer Engineering Department Shahid Behehsti UniversityTehranIran

With the growing use of service-oriented architecture for designing next generation software systems,the service composition problem and its execution complexity have become even more important in responding to different user *** gravitational search algorithm is one of the latest heuristic *** has a number of distinguishing features,such as rapid convergence,lower memory usage,and the use of particular parameters,for instance,the distance between the *** this paper,we propose a model for the optimization of the Web service composition problem based on qualitative measures and the gravitational search *** determine the efficacy of this proposed model we solve the problem with the particle swarm optimization algorithm for *** results show that the gravitational search algorithm has a high potential and substantial efficiency in finding the best combination of Web services.

关键词： Web service composition Gravitational search algorithm (GSA) Quality of service (QoS) Ontology engineering

Effects of oxygen therapy on the outcome of patients with acute myocardial infarction:A randomized clinical trial

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Journal of Acute Disease 2023年第2期12卷 45-50页

作者： Maryam Ziaei Hojjat rastegari Najafabadi Mahjoubeh Keykha Mehdi Galavi Ali Abdolrazaghnejad Alireza Bahmani Department of Emergency Medicine Khatam Al Anbia HospitalZahedan University of Medical SciencesZahedanIran Infectious Diseases and Tropical Medicine Research Center Research Institute of Cellular and Molecular Sciences in Infectious DiseasesZahedan University of Medical SciencesZahedanIran

Objective:To investigate the therapeutic effects of supplemental oxygen on patients with myocardial ***:This study was a randomized,double-blind clinical *** study population included all patients who were admitted to the emergency room of Ali-ibn-Abitaleb and Khatam-al-Anbia hospitals in Zahedan within six hours of the onset of classic symptoms of myocardial *** patients(n=47)were divided into two groups:the case group(with oxygen therapy)and the control group(without oxygen therapy).The initial follow-up was evaluated after one month and the second follow-up was evaluated after three months in the target population in terms of mortality caused by acute myocardial infarction,mortality caused by any other cause,and re-hospitalization caused by acute myocardial ***:Out of the 47 patients,27 were male(57.4%).The average age of the patients was(60.9±8.1)*** month after admission,2 patients(8.7%)in the case group and 2 patients(8.3%)in the control group died due to acute myocardial infarction.A total of 7 patients(14.9%)died three months after *** was no significant difference between the control and case groups in terms of mortality caused by acute ischemia within one and three *** one month,2 patients(8.7%)in the case group and 1 patient(4.2%)in the control group died of other *** three months,4 patients(8.5%)in total died for other *** was no significant difference between the control and case groups in terms of mortality due to other causes within one and three *** month after admission,5 patients(21.7%)of the case group and 4 patients(16.7%)of the control group were re-hospitalized due to acute myocardial *** the next three months,3 patients(13.0%)of the case group and 5 patients(20.8%)of the control group were *** was no significant difference between the control and case groups regarding the rate of re-hospitalization caused by acute my

关键词： Oxygen therapy Myocardial infarction Mortality Cardiac ischemia Hospitalization