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Magneto-Transport and Nanomagnet Dynamics in MgO-Based Magnetic Tunnel Junctions(MTJs)

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Communications in Theoretical Physics 2016年第2期65卷 254-258页

作者： nader Ghobadi Reza Daqiq Faculty of Science Department of PhysicsMalayer University

We investigate bias and different barrier thicknesses effects on quantities related to spin and charge currents in MgO-based magnetic tunnel junctions. Using the non-Equilibrium Green's function formalism, we demonstrate that the in-plane and out-of-plane components of the spin-transfer torque have asymmetric and symmetric behaviors respectively. Magneto-resistance also decreases with increasing barrier thickness. The Landau–Lifshits–Gilbert equation describes the dynamics of the magnetization made by spin transfer torque. Increasing in spin current above its critical value or smaller the magnet reduces the switching time which is major result for making of new memory devices.

关键词： magnetic tunnel junctions spin-transfer torque magneto-resistance nanomagnet dynamics

Removal of Reactive Red 198 from aqueous solution by combined method multi-walled carbon nanotubes and zero-valent iron:Equilibrium,kinetics,and thermodynamic

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Chinese Journal of Chemical Engineering 2016年第10期24卷 1448-1455页

作者： Sudabeh Pourfakari nader Yousefi Amir Hossein Mahvi Department of Environmental Health Engineering School of HealthShiraz University of Medical SdencesShirazIran Department of Environmental Health Engineering School of Public HealthTehran University of Medical SciencesTehranIran Center for Solid Waste Research Institute for Environmental ResearchTehran University of Medical SciencesTehranIran National Institute of Health Research Tehran University of Medical SciencesTehranIran

Dyes often include toxic,carcinogenic compounds and are harmful to humans' ***,removal of dyes from textile industry wastewater is *** present study aimed to evaluate the efficiency of the combination of zero valent iron(ZVI) powder and multi-walled carbon nanotubes(MWCNTs) in the removal of Reactive Red 198(RR198) dye from aqueous *** applied research was performed in a batch system in the laboratory *** study investigated the effect of various factors influencing dye removal,including contact time,p H,adsorbent dose,iron powder dose,initial dye concentration,and *** equilibrium adsorption data were analyzed using three common adsorption models:Langmuir,Freundlich and ***,kinetic and thermodynamic parameters were used to establish the adsorption *** results showed,in pH =3,contact time = 100 min,ZVI dose = 5000 mg·L^(-1),and MWCNTs dose = 600 mg·L^(-1)in 100 mg·L^(-1)dye concentration,the adsorption efficiency increased to 99.16%.Also,adsorption kinetics was best described by the pseudo-second-order *** data fitted well with the Freundlich isotherm(R2= 0.99).The negative values of ΔG0and the positive value of ΔH0(91.76) indicate that the RR198 adsorption process is spontaneous and *** to the results,the combination of MWCNTs and ZVI was highly efficient in the removal of azo dyes.

关键词：反应的红 198 MWCNT 吸附 ZVI 染料

Ionic Conductivity in Gelatin-Based Hybrid Solid Electrolytes:The Non-trivial Role of Nanoclay

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Journal of Materials Science & Technology 2014年第11期30卷 1096-1102页

作者： Ali Ghadami nader Taheri Qazvini Nasser Nikfarjam Polymer Division School of ChemistryCollege of ScienceUniversity of Tehran Biomaterials Research Center (BRC) University of Tehran

In this study, the ionic conductivity behavior in hybrid gelatin-based transparent electrolytes including various types of nanoclays with different size, shape and surface properties was characterized. The effects of nanoclay type and nanoclay concentration as well as different experimental conditions, e.g., pH, temperature and crosslinking were also investigated. In general, the impedance spectroscopy results suggested a non- trivial role for nanoclay. Regardless of the nanoclay type, the ionic conductivity slightly increased first and then decreased by increasing the nanoclay concentration. Furthermore, among sodium montmorillonite （Na＋MMT）, lithium montmorillonite （Li＋MMT）, laponite and hydrotalcite, the hybrid electrolytes prepared by Li＋MMT showed higher ionic conductivity. The results also showed that the chemical crosslinking along with sample preparation at optimum pH, where the gelatin chains might be efficiently adsorbed on exfoliated, negatively charged clay nanosheets, plays an important role. In comparison with the ionic conductivity of the neat sample at room temperature （～10-7 S cm-1）, a ten-fold increase was observed for the crosslinked sample containing 2 wt% of Li^＋MMT prepared at optimum pH 3.5. The conductivity behavior as a function of temperature revealed the obedience with the VogeI-Fulcher-Tammann （VFT） model for all samples, suggesting the important role of segmental motions in the ionic conductivity. Finally, a qualitative explanation was presented for the mechanism of the ionic conduction in gelatin-nanoclay hybrid electrolytes.

关键词： Gelatin Solid-state electrolytes Ionic conductivity Montmorillonitc Laponite Impedance spectroscopy

Densification behavior of yttria-stabilized zirconia powders for solid oxide fuel cell electrolytes

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Journal of Advanced Ceramics 2018年第4期7卷 325-335页

作者： Dhruba PANTHI nader HEDAYAT Yanhai DU College of Aeronautics and Engineering Kent State University Department of Engineering Technology Kent State University at Tuscarawas

Yttria-stabilized zirconia(YSZ) is the most common electrolyte material for solid oxide fuel cells. Herein, we conducted a comparative study on the densification behavior of three different kinds of commercial 8 mol% YSZ powders:(i) TZ-8Y(Tosoh, Japan),(ii) MELox 8Y(MEL Chemicals, UK), and(iii) YSZ-HT(Huatsing Power, China). The comparison was made on both the selfsupporting pellets and thin-film electrolytes coated onto a NiO–YSZ anode support. For the pellets, MELox 8Y showed the highest densification at lower sintering temperatures with 93% and 96% of the theoretical density at 1250 and 1300 ℃, respectively. Although YSZ-HT showed a higher sintering rate than TZ-8Y, a sintering temperature of 1350 ℃ was required for both the powders to reach 95% of the theoretical density. For the thin-film electrolytes, on the other hand, YSZ-HT showed the highest sintering rate with a dense microstructure at a co-sintering temperature of 1250 ℃. Our results indicate that besides the average particle size, other factors such as particle size distribution and post-processing play a significant role in determining the sintering rate and densification behavior of the YSZ powders. Additionally, a close match in the sintering shrinkage of the electrolyte and anode support is important for facilitating the densification of the thin-film electrolytes.

关键词： yttria-stabilized zirconia (YSZ) SOFC electrolyte densification shrinkage co-sintering

Investigating short-term and long-term binder performance of high-RAP mixtures containing waste cooking oil

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Journal of Traffic and Transportation Engineering(English Edition) 2019年第4期6卷 396-406页

作者： Hamed Majidifard nader Tabatabaee William Buttlar Department of Civil and Environmental Engineering University of MissouriColumbiaMO 65211USA Department of Civil Engineering Sharif University of TechnologyTehranIran

The environmental and economic benefits of recycling asphalt pavements have received much attention in recent years. Because of the increase in the cost of raw materials and energy carriers, the reuse of large portions of reclaimed asphalt pavement(RAP) is critical in reducing both the cost and environmental footprint of asphalt pavements. High-RAP mixtures are more prone to low temperature cracking and poor mixture workability because of the higher stiffness of RAP binder. Recycling agents are one of the additives which are used to improve these deficiencies. However, there is some ambiguity about the optimum content of recycling agent to assure proper performance of recycled asphalt pavement during its service life. The current study used 60% and 100% fractionated RAP with waste cooking oil as a recycling agent and crumb rubber to alleviate the aforementioned problems. Laboratory evaluation showed that increasing the amount of recycling agent in the high-RAP mixtures improved their workability and low temperature performance while decreasing moisture damage and rutting resistance. The long-term susceptibility to aging of recycled binder with the organically-based recycling agent was also investigated. A procedure to obtain the optimum percentage of recycling agent was devised to strike a balance between the performance characteristics of mixtures with a high-RAP content.

关键词： Asphalt Recycling RAP Cracking Recycling agent Rejuvenator

Novel technique of penetrating keratoplasty in high-risk grafts with significant corneal neovascularization

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International Journal of Ophthalmology(English edition) 2022年第9期15卷 1554-1556页

作者： Mohammad Soleimani nader Mohammadi Mansoor Shahriari Morteza Karimi Ahmed Alshaheeb Atefeh Khalili Mohammad Hossein Zamani Kasra Cheraqpour Eye Research Center Farabi Eye HospitalTehran University of Medical SciencesTehran ***Iran Imam Hossein Medical Center Shahid Beheshti University of Medical SciencesTehran ***Iran

Dear Editor,We write to introduce a novel technique of penetrating keratoplasty(PK)with lower risk of graft rejection in high-risk *** transplantation may be required in a variety of conditions such as keratoconus,pse... 详细信息

关键词： such keratoplasty corneal

Helicobacter is preserved in yeast vacuoles! Does Koch's postulates confirm it?

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World Journal of Gastroenterology 2017年第12期23卷 2266-2268页

作者： nader Alipour Nasrin Gaeini Department of Medical Microbiology and Biotechnology DEU University and Graduate of Middle East Technical university(METU) Sifa Medical center

The manuscript titled "Vacuoles of Candida yeast behave as a specialized niche for Helicobacter pylori(***)" not only has not been prepared in a scientific manner but the methodology used was not adequate, and therefore the conclusion reached was not correct. First of all, "yeast" is a broad terminology covering a great number of genera and species of unicellular micro-organisms. The authors should have defined the organism with its binary scientific name. This measure would allow experiment reproduction by the scientific community. Moreover, the criteria established by Robert Koch to identify a specific microorganism or pathogen was not adopted in the methodology used. Regarding the methodology applied, use of the chicken eggyolk(Ig Y) antibody and PCR of the apparently tainted yeast population to prove H. pylori existence in the yeast vacuoles might be main factors for their wrong conclusions. Bacterial tropism toward yeast extract is a known phenomenon, and yeast extract is one of the main ingredients in culture media. Their internalization through phagocytosis or similar pathways does not seem possible or practical because of the thick and cellulosic yeast wall. While the small size of yeast cells does not support their ability in harboring several H. pylori, other observations such as inefficiency of antifungal therapy as anti-Helicobacter therapy strongly reject the conclusion reached by the above-mentioned article.

关键词： Helicobacter pylori Yeast Acanthamoeba castellanii Koch’s postulates

Time-varying materials in the presence of dispersion:plane-wave propagation in a Lorentzian medium with temporal discontinuity

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Photonics Research 2021年第9期9卷 1842-1853页

作者： DIEGO M.SOLíS RAPHAEL KASTNER nader ENGHETA Department of Electrical and Systems Engineering University of PennsylvaniaPhiladelphiaPennsylvania 19104USA Tel Aviv University Tel Aviv 69978Israel

We study the problem of a temporal discontinuity in the permittivity of an unbounded medium with Lorentzian dispersion. More specifically, we tackle the situation in which a monochromatic plane wave forward-traveling in a(generally lossy) Lorentzian-like medium scatters from the temporal interface that results from an instantaneous and homogeneous abrupt temporal change in its plasma frequency(while keeping its resonance frequency constant). In order to achieve momentum preservation across the temporal discontinuity, we show how, unlike in the well-known problem of a nondispersive discontinuity, the second-order nature of the dielectric function now gives rise to two shifted frequencies. As a consequence, whereas in the nondispersive scenario the continuity of the electric displacement D and the magnetic induction B suffices to find the amplitude of the new forward and backward wave, we now need two extra temporal boundary conditions. That is, two forward and two backward plane waves are now instantaneously generated in response to a forward-only plane wave. We also include a transmission-line equivalent with lumped circuit elements that describes the dispersive time-discontinuous scenario under consideration.

关键词： discontinuity plane wave

Estimation of flexible pavement structural capacity using machine learning techniques

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Frontiers of Structural and Civil Engineering 2020年第5期14卷 1083-1096页

作者： nader KARBALLAEEZADEH Hosein GHASEMZADEH TEHRANI Danial MOHAMMADZADEH SHADMEHRI Shahaboddin SHAMSHIRBAND Civil Engineering Department Shahrood University of TechnologyShahrood ***Iran Department of Civil Engineering Ferdowsi University of MashhadMashhad ***Iran Department of Elite Relations with Industries Khorasan Construction Engineering OrganizationMashhad ***Iran Department for Management of Science and Technology Development Ton Duc Thang UniversityHo Chi Minh CityVietnam Faculty of Information Technology Ton Duc Thang UniversityHo Chi Minh CityVietnam

The most common index for representing structural condition of the pavement is the structural *** current procedure for determining structural numbers involves utilizing falling weight deflectometer and ground-penetrating radar tests,recording pavement surface deflections,and analyzing recorded deflections by back-calculation *** procedure has two drawbacks:falling weight deflectometer and ground-penetrating radar are expensive tests;back-calculation ways has some inherent shortcomings compared to exact methods as they adopt a trial and error *** this study,three machine learning methods entitled Gaussian process regression,M5P model tree,and random forest used for the prediction of structural numbers in flexible *** of this paper is related to 759 flexible pavement sections at Semnan and Khuzestan provinces in Iran and includes“structural number”as output and“surface deflections and surface temperature”as *** accuracy of results was examined based on three criteria of R,MAE,and *** the methods employed in this paper,random forest is the most accurate as it yields the best values for above criteria(R=0.841,MAE=0.592,and RMSE=0.760).The proposed method does not require to use ground penetrating radar test,which in turn reduce costs and work *** machine learning methods instead of back-calculation improves the calculation process quality and accuracy.

关键词： transportation infrastructure flexible pavement structural number prediction Gaussian process regression M5P model tree random forest