Search for: nanomagnetics
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    Investigation of phase diagrams for cylindrical Ising nanotube using cellular automata

    , Article Physics Letters, Section A: General, Atomic and Solid State Physics ; Volume 382, Issue 19 , May , 2018 , Pages 1291-1297 ; 03759601 (ISSN) Astaraki, M ; Ghaemi, M ; Afzali, K ; Sharif University of Technology
    Elsevier B.V  2018
    Recent developments in the field of applied nanoscience and nanotechnology have heightened the need for categorizing various characteristics of nanostructures. In this regard, this paper establishes a novel method to investigate magnetic properties (phase diagram and spontaneous magnetization) of a cylindrical Ising nanotube. Using a two-layer Ising model and the core-shell concept, the interactions within nanotube has been modelled. In the model, both ferromagnetic and antiferromagnetic cases have been considered. Furthermore, the effect of nanotube's length on the critical temperature is investigated. The model has been simulated using cellular automata approach and phase diagrams were... 

    Application potentials of microwave in nanomagnetic particle hyperthermia

    , Article IFMBE Proceedings, 7 September 2009 through 12 September 2009, Munich ; Volume 25, Issue 13 , 2009 , Pages 117-119 ; 16800737 (ISSN) ; 9783642038945 (ISBN) Janmaleki, M ; Mahmoudi, M ; Rafienia, M ; Peirovi, H ; Sharif University of Technology
    Magnetic Nanoparticle Hyperthermia is a new auxiliary technique for cancer treatment, in which the temperature of tumor cells is elevated and maintained to a therapeutic level. Up to now a few researches have been done for Microwave Magnetic Hyperthermia. The authors have studied behavior of MNPs in Microwave field for hyperthermia application. The frequency and power of produced field was 915MHz and 25 Watts. © 2009 Springer-Verlag  

    Synthesis, Characterization and Voltametric Study of Single Molecule Magnet Hybrid Salts [Mn3O(O2CMe)6(Pyr)3][Keggin-Polyoxometalates]Type

    , M.Sc. Thesis Sharif University of Technology Kazemi Movahed, Leily (Author) ; Mohammadi Boghaei, Davar (Supervisor)
    Molecular nanomagnets, also known as Single Molecule Magnets (SMMs) are a class of molecules that at low temperature exhibit magnetic hysteresis of pure molecular origin and not related to a cooperative effect. In the past fifteen years they have attracted great interest for their potentiality to act as magnetic memory units and for the many quantum effects in the dynamics of their magnetization. Organization of SMM on surfaces is the first step in order to address the magnetic state of a single molecule or to connect the molecule to a conducting substrate. The complex nature of SMMs and the peculiar origin of their magnetic bistability have been representing for half a decade an obstacle to... 

    Design and Synthesis of Heterogeneous Nano Catalyst Based on Immobilized Palladium Metal on Double Network Hydrogel and Its Application in Organic Reactions

    , M.Sc. Thesis Sharif University of Technology Ghasemzadeh, Solmaz (Author) ; Pourjavadi, Ali (Supervisor)
    In the past few decades, many attempts have been made to combine the benefits of homogeneous and heterogeneous catalysts. The immobilization of homogeneous catalysts onto the surface of heterogeneous supports is the result of such efforts. In this research, immobilized heterogeneous catalysts were designed and synthesized based on double network hydrogels, which produce from interpenetrating of two biocompatible and biodegradable polymer networks. In order to provide magnetic responsibility and easy separation of catalyst from the reaction mixture, the magnetic nanoparticles were dispersed onto the surface of double network hydrogel. Finally, various metal nanoparticles such as palladium and... 

    Design and Synthesis of Heterogeneous Nanocatalysts Based on Immobilized Metals on Polymeric Substrates and their Applications in Organic Reactions

    , Ph.D. Dissertation Sharif University of Technology Motamedi, Anahita (Author) ; Pourjavadi, Ali (Supervisor)
    Today, catalysts have shown the growing applications in chemical industries especially for drug synthesis. Using immobilized heterogeneous catalysts is a sensible way to benefit from advantages of both heterogeneous and homogeneous catalysts. In this regards, homogeneous catalysts are immobilized on to a solid support through various methods. However, low loading amount of homogenous part and subsequently insufficient catalytic activity are main limitations of immobilized heterogeneous catalysts. For this reason, polymeric supports have been introduced to immobilize metal ions or nanoparticles. These polymeric supports not only possess advantages such as anti-corrosive properties, simple... 

    Behavior of plasmonic nanoparticle array in near- and far-field coupling regimes for transverse electric and transverse magnetic polarizations

    , Article Journal of the Optical Society of America B: Optical Physics ; Volume 30, Issue 8 , 2013 , Pages 2286-2291 ; 07403224 (ISSN) Shahmansouri, A ; Rashidian, B ; Sharif University of Technology
    Optical Society of American (OSA)  2013
    We have previously reported the results of plasmonic behavior of an Au nanodisk array in the far-field coupling regime under oblique illumination with transverse electric polarization. In this paper, those results are studied in more detail. Here, results for transverse magnetic polarization are also presented and discussed. In addition to the far-field coupling regime, the results for the near-field coupling regime are also reported. Effects of different parameters, such as substrate thickness and array periodicity on the shape of plasmon spectra are discussed. It will be shown that in the far-field coupling regime, the diffractive grating orders can have a major role in the behavior of the... 

    Hydrazine-modified starch coated magnetic nanoparticles as an effective pH-responsive nanocarrier for doxorubicin delivery

    , Article Journal of Industrial and Engineering Chemistry ; Volume 39 , 2016 , Pages 203-209 ; 1226086X (ISSN) Zohreh, N ; Hosseini, S. H ; Pourjavadi, A ; Sharif University of Technology
    Korean Society of Industrial Engineering Chemistry  2016
    A novel, magnetic nanocarrier was successfully synthesized through a facile and economical producer in which Fe3O4 magnetic nanoparticles were coated by starch-g-poly (methyl methacrylate-co-PEG-acrylamide). The surface of nanocarrier was then modified by hydrazine to preparation of a pH-responsive carrier. The resulted nanocarrier was applied for delivery of doxorubicin (DOX) as an effective anti-cancer drug. DOX was reacted with hydrazine linkage on the surface of nanocarrier to form hydrazone bond. Due to the presence of numerous hydrazine groups on the surface of magnetic nanocarrier large amounts of DOX was loaded onto the carrier (327 mg g−1). © 2016 The Korean Society of Industrial... 

    Immobilized palladium nanoparticles on MNPs@A-N-AEB as an efficient catalyst for C-O bond formation in water as a green Solvent

    , Article Applied Organometallic Chemistry ; Volume 32, Issue 9 , 2018 ; 02682605 (ISSN) Moghaddam, F. M ; Eslami, M ; Sharif University of Technology
    John Wiley and Sons Ltd  2018
    Palladium nanoparticles immobilized on the magnetic nanoparticles@2-amino-N-(2-aminoethyl) benzamide (MNPs@A-N-AEB.Pd0) have been presented as an efficient, and reusable magnetically heterogeneous catalyst for the C-O coupling reaction, namely Ullmann condensation reactions in an aqueous medium. This heterogeneous catalyst shows superior reactivity for the C-O arylation of different aryl halide (chloride, bromide, and iodide) with phenol derivatives to afford the desired products in good to excellent yields within short reaction time. Moreover, the catalyst can be easily recovered and reused for seven runs without loss of catalytic activity. The catalyst was characterized by several... 

    Silver nanoparticles immobilized onto poly(4-vinylpyridine)-functionalized magnetic nanoparticles: a robust magnetically recyclable catalyst for oxidant-free alcohol dehydrogenation

    , Article Applied Organometallic Chemistry ; Volume 32, Issue 2 , February , 2018 ; 02682605 (ISSN) Bayat, A ; Shakourian Fard, M ; Talebloo, N ; Mahmoodi Hashemi, M ; Sharif University of Technology
    John Wiley and Sons Ltd  2018
    A heterogeneous and recyclable catalyst with a high loading of silver nanoparticles was synthesized via the silver nanoparticles being supported onto the surface of magnetic nanoparticles coated with poly(4-vinylpyridine). The synthesized catalyst was used in the dehydrogenation of alcohols to corresponding carbonyl compounds. A broad diversity of alcohols was converted into their corresponding carbonyl compounds in excellent yields. The catalyst was easily recovered by applying an external magnetic field and reused for seven reaction cycles without considerable loss of activity. The catalyst was fully characterized using various techniques. Copyright © 2017 John Wiley & Sons, Ltd  

    Post-buckling analysis of piezo-magnetic nanobeams with geometrical imperfection and different piezoelectric contents

    , Article Microsystem Technologies ; Volume 25, Issue 9 , 2019 , Pages 3477-3488 ; 09467076 (ISSN) Mirjavadi, S. S ; Forsat, M ; Barati, M. R ; Abdella, G. M ; Hamouda, A. M. S ; Mohasel Afshari, B ; Rabby, S ; Sharif University of Technology
    Springer Verlag  2019
    Thermal post-buckling behavior of a geometrically imperfect/perfect piezo-magnetic nano-scale beams made of two-phase composites is analyzed in the present paper based on nonlocal elasticity theory. For the first time, the material properties of the nanobeam are considered as functions of piezoelectric phase percentage. All previous investigations on piezo-magnetic nanobeams neglect the effect of geometrical imperfection which is very important since the nanobeams are not always ideal or perfect. The post-buckling problem of such nanobeams is solved by introducing an analytical approach to derive buckling temperatures. The present solution is simple and easily understandable. For both... 

    Suzuki–Miyaura coupling reaction in water in the presence of robust palladium immobilized on modified magnetic Fe3O4 nanoparticles as a recoverable catalyst

    , Article Applied Organometallic Chemistry ; Volume 32, Issue 2 , 2018 ; 02682605 (ISSN) Dadras, A ; Naimi Jamal, M. R ; Moghaddam, F. M ; Ayati, S. E ; Sharif University of Technology
    John Wiley and Sons Ltd  2018
    Aryl halides and especially inactive aryl chlorides were coupled to benzenoid aromatic rings in a Suzuki–Miyaura coupling reaction in the absence of organic solvents and toxic phosphine ligands. The reaction was catalysed by a recoverable magnetic nanocatalyst, Pd@Fe3O4, in aqueous media. This method is green, and the catalyst is easily removed from the reaction media using an external magnetic field and can be re-used at least 10 times without any considerable loss in its activity. The catalyst was characterized using scanning and transmission electron microscopies, thermogravimetric analysis, inductively coupled plasma spectroscopy, Fourier transform infrared spectroscopy, CHN analysis,... 

    Synthesis of Pd-based Magnetic Nanocatalyst and its Application on C-F Activation in Coupling Reactions, Using Sm for Cyanation Reacion and Diastereoselective Synthesis of Novel Hit Compounds and Their Pharmacological Evaluation

    , M.Sc. Thesis Sharif University of Technology Karimi, Ashkan (Author) ; Matloubi Moghaddam, Firouz (Supervisor)
    Formation of C-C and C-hetero atom bonds in coupling reactions is among the most important organic chemistry reactions, which is useful for achieving the complex molecules from simple ones. The goal of this thesis, was using the organometallic and also metal free methods in coupling reactions and getting the advantage of them in the synthesis of novel hit compounds. In this way, some novel reactions were designed and some novel catalysts were synthesised and identified. Finally, computational quantum chemistry and computational drug design were used as powerful tools for supporting the reaction mechanism, electronic and structural studies and pharmacological evaluation. C-X bond activation... 

    Fabrication of Magnetic Halloysite-Supported Catalyst for Reduction of Organic Dyes in Water

    , M.Sc. Thesis Sharif University of Technology Latifipour, Mostafa (Author) ; Kazemeini, Mohammad (Supervisor) ; Sadjadi, Samaheh (Supervisor)
    A new magnetic catalytic nanocomposite of Hal-MT-Cys-Ag/MNCD was fabricated and utilized for catalyzing reductive de-colorization of methyl orange and rhodamin B in aqueous media at room temperature. To prepare this material, Cl-functionalized halloysite nanoclay was successively reacted with melamine and 2,4,6-trichloro-1,3,5-triazine to furnish multi-nitrogen containing ligand on halloysite surface. Then, magnetic carbon dots were crafted through a facile method and decorated with Ag nanoparticles and cysteine to furnish Cys-Ag/MNCD species. The final nanocomposite was obtained via incorporation of this latter species onto functionalized halloysite. This was characterized through the XRD,... 

    Synthesis and Application of Transition Metal Spinels (Cu, Ni, Co, Pd and Fe) as a Catalyst in Organic Reactions

    , Ph.D. Dissertation Sharif University of Technology Daneshfar, Maryam (Author) ; Matloubi Moghaddam, Firouz (Supervisor)
    In the first section, due to the important role of nanocatalysts in different fields of chemistry, magnetic metal ferrite nanoparticles were synthesized. Ferrite nanoparticles were synthesized using co-precipitation method and were characterized. Then, these nanoparticles were applied as catalyst system for one-pot β-ketophosphonates and thiophosphate synthesis.This is a green and efficient route for S-P and C-P bond construction using copper ferrite nanoparticles as catalyst. The application of a highly active recyclable heterogeneous nanocopper ferrite catalyst for the oxyphosphorylation reaction of various alkenes was conducted under ligand-free conditions, in acetonitrile as solvent at... 

    An experimental study on the effect of ultrasonication on thermal conductivity of ferrofluid loaded with carbon nanotubes

    , Article Thermochimica Acta ; Volume 617 , October , 2015 , Pages 102-110 ; 00406031 (ISSN) Shahsavar, A ; Salimpour, M. R ; Saghafian, M ; Shafii, M. B ; Sharif University of Technology
    Elsevier  2015
    Nanofluids containing Fe3O4 and carbon nanotubes nanoparticles emulsified and dispersed using gum arabic (GA) and tetramethylammonium hydroxide (TMAH) were made and characterized for potential use as heat transfer fluids. Due to the interaction between the TMAH and GA molecules, the magnetic nanoparticles and CNTs were physically adsorbed. This paper reports an experimental work on the effect of ultrasonication on thermal conductivity of this aqueous suspension. The characterization and surface morphology of the dried samples were studied by using XRD and TEM measurements. Experiments were conducted in the magnetic nanoparticles mass concentration range 0.494-2.428%,... 

    Toward epileptic brain region detection based on magnetic nanoparticle patterning

    , Article Sensors (Switzerland) ; Volume 15, Issue 9 , September , 2015 , Pages 24409-24427 ; 14248220 (ISSN) Pedram, M. Z ; Shamloo, A ; Alasty, A ; Ghafar Zadeh, E ; Sharif University of Technology
    MDPI AG  2015
    Resection of the epilepsy foci is the best treatment for more than 15% of epileptic patients or 50% of patients who are refractory to all forms of medical treatment. Accurate mapping of the locations of epileptic neuronal networks can result in the complete resection of epileptic foci. Even though currently electroencephalography is the best technique for mapping the epileptic focus, it cannot define the boundary of epilepsy that accurately. Herein we put forward a new accurate brain mapping technique using superparamagnetic nanoparticles (SPMNs). The main hypothesis in this new approach is the creation of super-paramagnetic aggregates in the epileptic foci due to high electrical and... 

    Gold immobilized onto poly(ionic liquid) functionalized magnetic nanoparticles: A robust magnetically recoverable catalyst for the synthesis of propargylamine in water

    , Article RSC Advances ; Volume 5, Issue 43 , Apr , 2015 , Pages 34502-34510 ; 20462069 (ISSN) Moghaddam, F. M ; Ayati, S. E ; Hosseini, S. H ; Pourjavadi, A ; Sharif University of Technology
    Royal Society of Chemistry  2015
    Supported gold(III) on poly(ionic liquid) coated on magnetic nanoparticles produced a highly active, stable, recoverable and high loading for the synthesis of propargylamines (A3 coupling reaction) under green conditions. The reaction of aldehyde, secondary amine and alkyne were followed in aqueous media. The catalyst was characterized by TEM, TGA, AAS, FT-IR, XRD and EDX. A broad diversity of aldehydes, secondary amines, and alkynes, and a good to excellent yield of corresponding propargylamines were synthesized using 1.0% Au. The catalyst was easily recovered and reused 10 times without significant loss of activity  

    Silver nanoparticles supported on silica-coated ferrite as magnetic and reusable catalysts for oxidant-free alcohol dehydrogenation

    , Article RSC Advances ; Volume 5, Issue 29 , Jan , 2015 , Pages 22503-22509 ; 20462069 (ISSN) Bayat, A ; Shakourian Fard, M ; Ehyaei, N ; Mahmoodi Hashemi, M ; Sharif University of Technology
    Royal Society of Chemistry  2015
    Silver (0) nanoparticles supported on silica-coated ferrite were synthesized to be used as an efficient and recyclable heterogeneous catalyst for oxidant-free dehydrogenation of alcohols to the corresponding carbonyl compounds. The catalyst can be easily recovered and reused for 8 reaction cycles without considerable loss of activity. The facile recovery of the catalyst is carried out by applying an external magnetic device. The catalyst was fully characterized by the techniques of TEM, SEM, XRD, EDS, ICP-AES, and VSM. This journal is  

    Effects of Ce–Co substitution on structural, magnetic and dielectric properties of M-type barium hexaferrite nanoparticles synthetized by sol–gel auto-combustion route

    , Article Journal of Materials Science: Materials in Electronics ; Volume 26, Issue 4 , 2015 , Pages 2134-2144 ; 09574522 (ISSN) Lalegani, Z ; Nemati, A ; Sharif University of Technology
    Springer New York LLC  2015
    M-type Ce–Co substituted barium hexaferrite nanoparticles were synthesized by sol–gel auto-combustion route. The general formula of ferrites was Ba1−xCexFe12−xCoxO19 in which the x was considered to be: x = 0, 0.1, 0.2, and 0.3. The formed phases in the samples were characterized by using X-ray diffraction, Fourier transform infrared spectroscopy, Mössbauer spectroscopy and vibrating sample magnetometer. The results indicated that an increase in substitutional ion amount caused to decrease vibration frequencies of Fe–O band in the tetrahedral site due to the substitution of heavier Co2+ ion for Fe3+ ion in the tetrahedral site. Moreover, some of Ce3+ ions was transformed to Ce4+ and... 

    Dendritic magnetite decorated by pH-responsive PEGylated starch: A smart multifunctional nanocarrier for the triggered release of anti-cancer drugs

    , Article RSC Advances ; Volume 5, Issue 60 , Jun , 2015 , Pages 48586-48595 ; 20462069 (ISSN) Pourjavadi, A ; Mazaheri Tehrani, Z ; Hosseini, S. H ; Sharif University of Technology
    Royal Society of Chemistry  2015
    In the present study, we designed a pH-responsive drug nanocarrier based on polyamidoamine-modified Fe3O4 nanoparticles coated by PEGylated starch-co-poly(acrylic acid). This carrier was used for the controlled release of doxorubicin as an anticancer drug model. The purpose of using the polyethylene glycol moiety is to generate a biostable nanocarrier in blood stream as it has been reported widely in the pharmaceutical literature. The use of a poly(acrylic acid) segment also provided pH-sensitivity to the polymer. Besides, the magnetic nanoparticles facilitate the cancer cell targeting with an external magnetic field located near the tumor site. This carrier was...