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Comparative analysis of unipolar and bipolar plasma electrolytic oxidation coatings on Al-Mg laminated macro composites

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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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Corrosion and wear resistance of coatings produced on AZ31 Mg alloy by plasma electrolytic oxidation in silicate-based K2TiF6 containing solution:Effect of waveform

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Journal of Magnesium and Alloys 2022年第9期10卷 2574-2587页

作者： maryam rahmati Keyvan Raeissi Mohammad Reza Toroghinejad Amin Hakimizad Monica Santamaria Department of Materials Engineering Isfahan University of TechnologyIsfahan 84156-83111Iran Yekta Mobaddel Pars Co. Science and Technology CampusYazd UniversityYazd 89158-18411Iran Dipartimento di Ingegneria Università di PalermoViale Delle ScienzeEd.690128PalermoItaly

In this research,plasma electrolytic oxidation coatings were prepared on AZ31 Mg alloy in a silicate-based solution containing K_(2)TiF_(6) using bipolar and soft sparking waveforms with 10,20,and 30%cathodic duty *** coatings displayed a net-like surface morphology consisted of irregular micro-pores,micro-cracks,fused oxide particles,and a sintered *** to the incorporation of TiO_(2) colloidal particles and the cathodic pulse repair effect,most of the micro-pores were ***-term corrosion performance of the coatings was investigated using electrochemical impedance spectroscopy during immersion in 3.5 wt.%NaCl solution up to 14 *** coating grown by the soft sparking waveform with a 20%cathodic duty cycle having the lowest porosity(6.2%)and a sharp layer concentrated in F element at the substrate/coating interface shows the highest corrosion *** friction coefficient of this coating has remained stable during the sliding even under 5 N normal load,showing relatively higher wear resistance than other *** coating produced using the equivalent unipolar waveform,as the reference specimen,showed the highest friction coefficient and the lowest wear resistance despite its highest micro-hardness.

关键词： Plasma electrolytic oxidation Pulsed waveforms AZ31 Mg alloy Dipotassium titanium hexafluoride Corrosion resistance Wear resistance

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Predicting density log from well log using machine learning techniques and heuristic optimization algorithm:A comparative study

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Petroleum Research 2024年第2期9卷 176-192页

作者： Mehdi rahmati Ghasem Zargar Abbas Ayatizadeh Tanha National Iranian Drilling Company Well Logging DepartmentAhwazIran Faculty Member of Petroleum University of Technology Iran Department of Petroleum Engineering Tarbiat Modares UniversityTehranIran

In the petroleum industry,the analysis of petrophysical parameters is critical for efficient reservoir management,production optimization,development strategies,and accurate hydrocarbon reserve *** recent years,the integration of machine learning methodologies has revolutionized the field,addressing challenges in geology,geophysics,and petroleum engineering,even when confronted with limited or imperfect *** study focuses on the prediction of density logs,a pivotal factor in evaluating reservoir hydrocarbon *** is important to note that during well logging operations,log data for specific depths of interest may be missing or incorrect,presenting a significant *** tackle this issue,we employed the Adaptive Neuro-Fuzzy Inference System(ANFIS)and Artificial Neural Networks(ANN)in combination with advanced optimization algorithms,including Particle Swarm Optimization(PSO),Imperialist Competitive Algorithms(ICA),and Genetic Algorithms(GA).These methods exhibit promising performance in predicting density logs from gamma-ray,neutron,sonic,and photoelectric log ***,our results highlight that the Genetic Algorithms-based Artificial Neural Network(GA-ANN)approach outperforms all other methods,achieving an impressive Mean Squared Error(MSE)of *** comparison,ANFIS records an MSE of 0.0015,ICA-ANN 0.0090,PSO-ANN 0.0093,and ANN 0.0183.

关键词： Density log Machine learning approaches Artificial neural networks(ANN) Adaptive neuro-fuzzy inference system(ANFIS) Optimization algorithm

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Effects of mesenchymal stem cell on dopaminergic neurons,motor and memory functions in animal models of Parkinson's disease:a systematic review and meta-analysis

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Neural Regeneration Research 2024年第7期19卷 1584-1592页

作者： Jong Mi Park Masoud rahmati Sang Chul Lee Jae Il Shin Yong Wook Kim Department and Research Institute of Rehabilitation Medicine Yonsei University College of MedicineSeoulSouth Korea Department of Physical Education and Sport Sciences Faculty of Literature and Human SciencesLorestan UniversityKhoramabadIran Department of Pediatrics Yonsei University College of MedicineSeoulSouth Korea

Parkinson’s disease is chara cterized by the loss of dopaminergic neurons in the substantia nigra pars com pacta,and although restoring striatal dopamine levels may improve symptoms,no treatment can cure or reve rse the disease *** cell therapy has a regenerative effect and is being actively studied as a candidate for the treatment of Parkinson’s *** stem cells are considered a promising option due to fewer ethical concerns,a lower risk of immune rejection,and a lower risk of *** performed a meta-analysis to evaluate the therapeutic effects of mesenchymal stem cells and their derivatives on motor function,memory,and preservation of dopamine rgic neurons in a Parkinson’s disease animal *** searched bibliographic databases(PubMed/MEDLINE,Embase,CENTRAL,Scopus,and Web of Science)to identify articles and included only pee r-reviewed in vivo interve ntional animal studies published in any language through J une 28,*** study utilized the random-effect model to estimate the 95%confidence intervals(CI)of the standard mean differences(SMD)between the treatment and control *** use the systematic review center for laboratory animal expe rimentation’s risk of bias tool and the collaborative approach to meta-analysis and review of animal studies checklist for study quality assessment.A total of 33studies with data from 840 Parkinson’s disease model animals were included in the *** with mesenchymal stem cells significantly improved motor function as assessed by the amphetamine-induced rotational *** the stem cell types,the bone marrow MSCs with neurotrophic factor group showed la rgest effect size(SMD[95%CI]=-6.21[-9.50 to-2.93],P=0.0001,I^(2)=0.0%).The stem cell treatment group had significantly more tyrosine hydroxylase positive dopamine rgic neurons in the striatum([95%CI]=1.04[0.59 to 1.49],P=0.0001,I^(2)=65.1%)and substantia nigra(SMD[95%CI]=1.38[0.89 to 1.87],P=0.0001,I^(2)=75.3%),indicating a

关键词： animal animal experimentation mesenchymal stem cells models Parkinson’s disease stem cell transplantation

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Coating doxycycline on titanium-based implants: Two in vivo studies

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Bioactive Materials 2020年第4期5卷 787-797页

作者： maryam rahmati Ståle Petter Lyngstadaas Janne E.Reseland Ingrid Andersbakken Heidi Straume Haugland Mónica López-Peña Antonio Gonzalez Cantalapiedra Fernando Maria Guzon Muñoz Håvard Jostein Haugen Department of Biomaterials Institute of Clinical DentistryUniversity of Oslo0317OsloNorway Universidade de Santiago de Compostela Facultad de Veterinaria Campus Universitarios/n27002LugoSpain

Regardless of the substantial progress in designing titanium-based dental implants and aseptic techniques,infection remains as the most common complication after implantation ***,having a weakened immune system or systematic diseases is not seen as contraindicated for dental implants anymore,controlling the immune system is required to avoid surgical site infections after *** patients have to control the surgical site infections by taking a high daily dose of oral antibiotics after dental *** antibiotics oral administration has many side effects such as gastrointestinal symptoms,skin rashes and *** antibiotics on the biomaterials surface could be a promising solution to reduce these disadvantages through locally releasing antibiotics in a controlled *** aim of this study was to investigate the effects of doxycycline coating layer on titanium-zirconium alloy surfaces in vitro and in *** our previous studies,we demonstrated the chemical presence of doxycycline layer in *** this study,we examined its physical presence using field emission scanning electron microscope and confocal *** also analyzed its controlled released manner using Nano-Drop UV Vis *** in vitro characterization of the coating layer,we evaluated its effects on the implant osseointegration in dogs and *** histological and histomorphometrical results exhibited no significant difference between doxycycline coated and uncoated groups regarding the implants osseointegration and biocompatibility for dental ***,coating a doxycycline layer on TiZr implants could be favorable for reducing or removing the antibiotics oral administration after the implantation surgery.

关键词： Titanium-zirconium Doxycycline Antibiotic Coating SLActive

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Aryl hydrocarbon receptor dynamics in esophageal squamous cell carcinoma:From immune modulation to therapeutic opportunities

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World Journal of Experimental Medicine 2024年第3期14卷 48-56页

作者： Mina rahmati Hassan Moghtaderi Saeed Mohammadi Ahmed Al-Harrasi Biotechnology Research Center Pasteur Institute of IranTehran ***TehranIran Natural and Medical Sciences Research Center University of NizwaNizwa 616Ad DakhiliyahOman

Esophageal squamous cell carcinoma(ESCC)is a substantial global health *** escape mechanisms are important in ESCC progression,enabling cancer cells to escape the surveillance of the host immune *** key player in this process is the Aryl Hydrocarbon Receptor(AhR),which influences multiple cellular processes,including proliferation,differentiation,metabolism,and immune *** AhR signaling participates in ESCC development by stimulating carcinogenesis,epithelial-mesenchymal transition,and immune *** AhR signaling is a potential therapeutic approach for ESCC,with AhR ligands showing efficacy in preclinical ***,modification of AhR ligands and combination therapies present new opportunities for therapeutic *** review aims to address the knowledge gap related to the role of AhR signaling in ESCC pathogenesis and immune escape.

关键词： Esophageal squamous cell carcinoma Aryl hydrocarbon receptor Immune escape Tumor microenvironment Immunosuppression Therapeutic targeting

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Revisiting the space-time gradient method:A time-clocking perspective, high order difference time discretization and comparison with the harmonic balance method

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Chinese Journal of Aeronautics 2022年第11期35卷 45-58页

作者： Boqian WANG Dingxi WANG Mohammad rahmati Xiuquan HUANG School of Power and Energy Northwestern Polytechnical UniversityXi'an 710072China Department of Mechanical and Construction Engineering Northumbria UniversityNewcastle upon Tyne NEI 8STUnited Kingdom

This paper revisits the Space-Time Gradient(STG) method which was developed for efficient analysis of unsteady flows due to rotor–stator interaction and presents the method from an alternative time-clocking perspective. The STG method requires reordering of blade passages according to their relative clocking positions with respect to blades of an adjacent blade row. As the space-clocking is linked to an equivalent time-clocking, the passage reordering can be performed according to the alternative time-clocking. With the time-clocking perspective, unsteady flow solutions from different passages of the same blade row are mapped to flow solutions of the same passage at different time instants or phase angles. Accordingly, the time derivative of the unsteady flow equation is discretized in time directly, which is more natural than transforming the time derivative to a spatial one as with the original STG method. To improve the solution accuracy, a ninth order difference scheme has been investigated for discretizing the time derivative. To achieve a stable solution for the high order scheme, the implicit solution method of Lower-Upper Symmetric GaussSeidel/Gauss-Seidel(LU-SGS/GS) has been employed. The NASA Stage 35 and its blade-countreduced variant are used to demonstrate the validity of the time-clocking based passage reordering and the advantages of the high order difference scheme for the STG method. Results from an existing harmonic balance flow solver are also provided to contrast the two methods in terms of solution stability and computational cost.

关键词： Harmonic balance method High order difference scheme Passage reordering Space-time gradient method Unsteady flows

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Recent progress and perspective in additive manufacturing of EMI shielding functional polymer nanocomposites

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Nano Research 2023年第1期16卷 1-17页

作者： Amirjalal Jalali Ruiyan Zhang Reza rahmati Mohammadreza Nofar Mohini Sain Chul B.Park Center for Biocomposites&Biomaterials Processing John H.Daniels Faculty of ArchitectureLandscapeand DesignUniversity of TorontoTorontoOntario M5S 3B3Canada Microcellular Plastics Manufacturing Laboratory Department of Mechanical and Industrial EngineeringUniversity of Toronto5 King's College RoadTorontoOntario M5S 3G8Canada State Key Laboratory of High-Efficiency Utilization of Coal and Green Chemical Engineering Key Laboratory of Photovoltaic MaterialsSchool of Materials and New EnergyNingxia UniversityYinchuan 750021China Metallurgical&Materials Engineering Department Faculty of Chemical and Metallurgical EngineeringIstanbul Technical UniversityMaslakIstanbul 34469Turkey

Because of rapid progress in the electronics industry,the market has faced a huge demand for novel materials in the field of electromagnetic interference(EMI)*** functional polymer composites have demonstrated great potential to fulfill this *** synthesize the polymeric composites,functional conductive nanoadditives such as graphene,carbon nanotubes,and MXene are commonly added to polymeric matrices,and the conductive polymer nanocomposites exhibit promising electrical conductivity as well as EMI shielding *** manufacturing(AM),also referred to as threedimensional(3D)printing,has been increasingly employed to fabricate complicated geometry components in the medical,aerospace,and automotive *** has also been used to fabricate advanced EMI shielding materials for sensors,supercapacitors,energy storage devices,and flexible *** review aims at introducing the different 3D printing methods applied for the fabrication of EMI shielding polymer *** impact of the AM process on the functionality of the samples is also ***,the influence of the nanofiller type and amount on the microstructure and performance of the fabricated nanocomposites is ***,the prospects and recommended works for future study are outlined.

关键词： additive manufacturing electromagnetic interference(EMI)shielding functional polymer nanocomposites stretchable electronics

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Dilation angle variations in plastic zone around tunnels in rocks-constant or variable dilation parameter

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Journal of Central South University 2018年第10期25卷 2550-2566页

作者： Hamed MOLLADAVOODI Marzieh rahmati Department of Mining and Metallurgy Amirkabir University of Technology

Dilation angle is a significant parameter needed for numerical simulation of *** though dilation parameter is physically variable and dependent on confinement and experienced shear plastic strain based on the existing dilation models,numerical simulations of tunnels and underground openings with constant dilation parameter usually lead to satisfactory results in practical *** study aims to find out why constant dilation angle is enough under practical conditions to simulate numerically tunnels and underground excavations in spite of the fact that dilation angle is variable in laboratory and experimental *** this aim,this work studies how mobilized dilation angle varies in a plastic zone surrounding a *** the circular tunnel under uniform in situ stress field,the stepwise finite difference approximation analytical solution considering strain softening rock mass behavior with mobilized dilation angle was used to study how mobilized dilation angle varies in plastic zone around tunnel under very different *** practical conditions determined in this study,dilative behavior of all over the plastic zone around the tunnel can be approximated to constant dilation angle in the middle region of the plastic ***,the plastic zone displacements for mobilized and constant dilation angle models are compared with each *** investigation under more general non-uniform in situ stress conditions and non-circular tunnels is performed by using the commercial finite difference software to numerically simulate the Mine-by experimental tunnel of AECL(Atomic Energy of Canada Limited)and the arched *** the Mine-by and arched tunnels were numerically simulated based on the mobilized dilation angle model,the variability associated with dilation angle around the simulated Mine-by and arched tunnels is insignificant,and dilation angle is approximately constant in the plastic zone.

关键词： dilation post-peak behavior plastic zone strain softening

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A rapid and efficient method for the synthesis of 14H-dibenzo[α.j]xanthenes,aryl-5H-dibenzo[b.i]xanthene-5,7,12,14-(13H)-tetraone and 1,8-dioxooctahydroxanthenes by acidic ionic liquid

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Chinese Chemical Letters 2010年第7期21卷 761-764页

作者： Abbas rahmati Department of Chemistry University of IsfahanP.O.Box 81746-7344IsfahanIran

Various xanthenes have been synthesized by the condensation ofβ-naphthol,2-hydroxynaphthalene-1,4-dione or dimedone with various aldehydes in the presence of trifluoroacetic acid as catalyst in 1,1,3,3-N,N,N′,N′-te... 详细信息

关键词： Ionic liquid 14H-Dibenzo[α.j]xanthenes β-Naphthol 2-Hydroxynaphthalene-1 4-dione Dimedone

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