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Beam manipulation by hybrid plasmonic-dielectric metasurfaces
, Article Plasmonics ; 2019 ; 15571955 (ISSN) ; Hemmatyar, O ; Kavehvash, Z ; Sharif University of Technology
Springer
2019
Abstract
A hybrid plasmonic-dielectric metasurface is proposed in order to manipulate beam propagation in desired manners. The metasurface is composed of patterned hybrid graphene-silicon nano-disks deposited on a low-index substrate, namely silica. It is shown that the proposed hybrid metasurface simultaneously benefits from the advantages of graphene-based metasurfaces and dielectric ones. Specially, we show that the proposed hybrid metasurface not only provides reconfigurability, just like previously proposed graphene-based metasurfaces, but also similar to dielectric metasurfaces, is of low loss and CMOS-compatible. Such exceptional features give the metasurface exceptional potentials to realize...
Preparation of polyaniline/graphene coated wearable thermoelectric fabric using ultrasonic-assisted dip-coating method
, Article Materials for Renewable and Sustainable Energy ; Volume 9, Issue 4 , 2020 ; Ramazani Saadatabadi, A ; Siadati, M. H ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2020
Abstract
Abstract: The use of thermoelectric fabrics for powering wearable devices is expected to become widespread soon. A thermoelectric fabric was prepared by coating nanocomposite of polyaniline/graphene nanosheets (PANI/GNS) on a fabric. Four samples of the fabric containing different wt% of GNS (0.5, 2.5, 5, and 10) were prepared. To characterize the samples, Fourier transform infrared (FTIR) spectra, attenuated total reflectance-Fourier transform infrared (AT-FTIR) spectra, field-emission scanning electron microscopy (FE-SEM), electrical conductivity and Seebeck coefficient measurements were used. The electrical conductivity increased from 0.0188 to 0.277 S cm−1 (from 0.5 to 10 wt% of the GNS...
Beam manipulation by hybrid plasmonic-dielectric metasurfaces
, Article Plasmonics ; Volume 15, Issue 3 , 2020 , Pages 639-645 ; Hemmatyar, O ; Kavehvash, Z ; Sharif University of Technology
Springer
2020
Abstract
A hybrid plasmonic-dielectric metasurface is proposed in order to manipulate beam propagation in desired manners. The metasurface is composed of patterned hybrid graphene-silicon nano-disks deposited on a low-index substrate, namely silica. It is shown that the proposed hybrid metasurface simultaneously benefits from the advantages of graphene-based metasurfaces and dielectric ones. Specially, we show that the proposed hybrid metasurface not only provides reconfigurability, just like previously proposed graphene-based metasurfaces, but also similar to dielectric metasurfaces, is of low loss and CMOS-compatible. Such exceptional features give the metasurface exceptional potentials to realize...
Tailoring the graphene polarity through the facile and one-step electrochemical exfoliation in low concentration of exfoliation agents
, Article FlatChem ; Volume 22 , July , 2020 ; Pircheraghi, G ; Khonakdar, H. A ; Sharif University of Technology
Elsevier B.V
2020
Abstract
Graphene nanoplatelets with different oxidation degrees, from low polar few-layer graphene (FLG) to high polar graphene oxide (GO) in the same current and concentration of the oxidizing agent in low concentrated electrolytes ((NH4)2SO4, Sodium Do-decyl Sulfate (SDS), and HNO3) are prepared through a one-step and cost-effective electrochemical synthesis route to find the effect of electrolyte on the surface polarity of powders. In order to use a wide variety of electrolytes, basic, neutral, and acidic electrolytes in a concentration as low as 0.2 M are used. Exfoliated graphene nanoplatelets without any further process are obtained to simplify and accelerate the synthesis process. Several...
Synthesis of magnetic bio-nanocomposites for drug release and adsorption applications
, Article South African Journal of Chemical Engineering ; Volume 42 , 2022 , Pages 115-126 ; 10269185 (ISSN) ; Meskini, M ; Qarebaghi, L. M ; Salami, M ; Forouzandehdel, S ; Cheraghali, M ; Sharif University of Technology
Elsevier B.V
2022
Abstract
Aims: Synthesis of nanocarrier Fe3O4/silica-starch/PNVCL for drug delivery and Fe3O4/GO-starch for antibiotic removal applications Background: In the first part, the new magnetic nanocomposite including Fe3O4 nanoparticles coated with silica, anchored starch nanoparticles, and poly(N-vinylcaprolactam) and then, loaded by acetazolamide. In the second part, magnetic starch nanocomposites were synthesized and modified with graphene oxide. Methods: The drug loading, release and intrinsic cytotoxicity were measured. Also, the potential of Fe3O4/GO-starch as an adsorbent to remove cephalexin antibiotics from aqueous solutions was evaluated. Result: In the first part, the maximum drug adsorption...
Fabrication and evaluation of in vitro studies of biodegradable and antibacterial composite scaffolds based on polylactic acid-polycaprolactone-hydroxyapatite reinforced with graphene and zinc oxide nanoparticles for use in orthopedic surgery
, Article Iranian Journal of Materials Science and Engineering ; Volume 19, Issue 2 , 2022 , Pages 1-19 ; 17350808 (ISSN) ; Saadatabadi, A. R ; Asefnejad, A ; Sharif University of Technology
Iran University of Science and Technology
2022
Abstract
Introduction: Fabrication of fully optimized tissue-engineered materials in order to simulating the natural structure, and enhancing the biological properties of damaged tissue is one of the major challenges in biomedical engineering and regeneration medicine. Although polymeric based membranes have revealed noticeable advancements in bone regeneration, their mechanical stiffens, electrical conductivity and bioactivity need to be tolerated. Methods: Therefore, the present study is designed to generate a multifunctional biomaterial based on polylactic acid (PLA)/ polycaprolactone (PCL)/hydroxyapatite (HA) nanocomposite containing zinc oxide (ZnO) and Graphene (Gr) nanoparticles employing...
The Fabrication and Characterization of Graphene by Mechanical Exfoliation Method and a Review on Graphene Field Effect Transistors
, M.Sc. Thesis Sharif University of Technology ; Akhavan, Omid (Supervisor)
Abstract
Graphene is a semiconductor with zero band gap. Due to electron ballistic transportation and having a single atom thickness of graphene, it is counted as an ideal material in Nano-electronic industry and essential candidate for fabrication of next generation of transistors. The Fermi level in graphene is located between Conduction and valance bands in a Dirac point. Due to low resistance, graphene has a substantial sensitivity near the Dirac point to local carrier density changes. This feature makes delicate detection of electromagnetic waves and gas sensing by graphene field effect transistors (GFETs). In this thesis, fabrication and characterization of graphene field effect transistor on...
In vivo SPECT imaging of tumors by 198,199Au-labeled graphene oxide nanostructures
, Article Materials Science and Engineering C ; Vol. 45 , 2014 , pp. 196-204 ; ISSN: 09284931 ; Akhavan, O ; Rahighi, R ; Aboudzadeh, M. R ; Karimi, E ; Afarideh, H ; Sharif University of Technology
Abstract
Graphene oxide (GO) sheets functionalized by aminopropylsilyl groups (8.0 wt.%) were labeled by 198,199Au nanoparticle radioisotopes (obtained through reduction of HAuCl4 in sodium citrate solution followed by thermal neutron irradiation) for fast in vivo targeting and SPECT imaging (high purity germanium-spectrometry) of tumors. Using instant thin layer chromatography method, the physicochemical properties of the amino-functionalized GO sheets labeled by 198,199Au NPs (198,199Au@AF-GO) were found to be highly stable enough in organic phases, e.g. a human serum, to be reliably used in bioapplications. In vivo biodistribution of the 198,199Au@AF-GO composite was investigated in rats bearing...
Irreversibility in response to forces acting on graphene sheets
, Article Physical Review Letters ; Volume 104, Issue 19 , May , 2010 ; 00319007 (ISSN) ; Asgari, R ; Tabar, M. R. R ; Sharif University of Technology
2010
Abstract
The amount of rippling in graphene sheets is related to the interactions with the substrate or with the suspending structure. Here, we report on an irreversibility in the response to forces that act on suspended graphene sheets. This may explain why one always observes a ripple structure on suspended graphene. We show that a compression-relaxation mechanism produces static ripples on graphene sheets and determine a peculiar temperature Tc, such that for T
Current-voltage characteristics of graphane p-n junctions
, Article IEEE Transactions on Electron Devices ; Volume 57, Issue 1 , 2010 , Pages 209-214 ; 00189383 (ISSN) ; Khorasani, S ; Sharif University of Technology
2010
Abstract
In contrast to graphene, which is a gapless semiconductor, graphane, the hydrogenated graphene, is a semiconductor with an energy gap. Together with the 2-D geometry, unique transport features of graphene, and the possibility of doping graphane, p and n regions can be defined so that 2-D p-n junctions become feasible with small reverse currents. This paper introduces a basic analysis to obtain the current-voltage characteristics of such a 2-D p-n junction based on graphane. As we show, within the approximation of Shockley's law of junctions, an ideal I-V characteristic for this p-n junction is to be expected
Recent progress in molecular simulation of nanoporous graphene membranes for gas separation
, Article Journal of the Korean Physical Society ; Volume 71, Issue 1 , 2017 , Pages 54-62 ; 03744884 (ISSN) ; Baniasadi, A ; Moradi, M ; Sharif University of Technology
Abstract
If an ideal membrane for gas separation is to be obtained, the following three characteristics should be considered: the membrane should be as thin as possible, be mechanically robust, and have welldefined pore sizes. These features will maximize its solvent flux, preserve it from fracture, and guarantee its selectivity. Graphene is made up of a hexagonal honeycomb lattice of carbon atoms with sp2 hybridization state forming a one-atom-thick sheet of graphite. Following conversion of the honeycomb lattices into nanopores with a specific geometry and size, a nanoporous graphene membrane that offers high efficiency as a separation membrane because of the ultrafast molecular permeation rate as...
Applications of graphene and graphene oxide in smart drug/gene delivery: Is the world still flat?
, Article International Journal of Nanomedicine ; Volume 15 , 2020 , Pages 9469-9496 ; Mirkiani, S ; Mozaffari, N ; Abdolahi Sadatlu, M. A ; Ghasemi, A ; Abbaspour, S ; Akbarian, M ; Farjadian, F ; Karimi, M ; Sharif University of Technology
Dove Medical Press Ltd
2020
Abstract
Graphene, a wonder material, has made far-reaching developments in many different fields such as materials science, electronics, condensed physics, quantum physics, energy systems, etc. Since its discovery in 2004, extensive studies have been done for understanding its physical and chemical properties. Owing to its unique characteristics, it has rapidly became a potential candidate for nano-bio researchers to explore its usage in biomedical applications. In the last decade, remarkable efforts have been devoted to investigating the biomedical utilization of graphene and graphene-based materials, especially in smart drug and gene delivery as well as cancer therapy. Inspired by a great number...
Cysteic acid grafted to magnetic graphene oxide as a promising recoverable solid acid catalyst for the synthesis of diverse 4H-chromene
, Article Scientific Reports ; Volume 10, Issue 1 , December , 2020 ; Eslami, M ; Hoda, G ; Sharif University of Technology
Nature Research
2020
Abstract
4H-chromenes play a significant role in natural and pharmacological products. Despite continuous advances in the synthesis methodology of these compounds, there is still a lack of a green and efficient method. In this study, we have designed cysteic acid chemically attached to magnetic graphene oxide (MNPs·GO-CysA) as an efficient and reusable solid acid catalyst to synthesize 4H-chromene skeletons via a one-pot three components reaction of an enolizable compound, malononitrile, an aldehyde or isatin, and a mixture of water–ethanol as a green solvent. This new heterogeneous catalyst provides desired products with a good to excellent yield, short time, and mild condition. This procedure...
Enhancement of self-powered humidity sensing of graphene oxide–based triboelectric nanogenerators by addition of graphene oxide nanoribbons
, Article Microchimica Acta ; Volume 188, Issue 8 , 2021 ; 00263672 (ISSN) ; Mohammadpour, R ; Asadian, E ; Fardindoost, S ; Sasanpour, P ; Sharif University of Technology
Springer
2021
Abstract
A triboelectric nanogenerator (TENG) electrode sensitive to the adsorption of water molecules has been introduced to create a self-powered humidity sensor. Graphene oxide (GO) nanosheets and graphene oxide nanoribbon (GONR) possessing oxygenated functional groups, as well as high dielectric constants, have been proposed as appropriate candidates for this purpose. GO papers have been fabricated in three forms, i.e. pure GO paper, uniform composites of GONR and GO, and double-layer structures of GONR on top of GO. Results showed that all of the prepared paper-based TENGs revealed excellent performances by maximum output voltage above 300 V. As active humidity sensors, the maximum voltage...
Electrically conductive carbon-based (bio)-nanomaterials for cardiac tissue engineering
, Article Bioengineering and Translational Medicine ; 2022 ; 23806761 (ISSN) ; Rabiee, M ; Baheiraei, N ; Ghahremanzadeh, R ; Salarian, R ; Rabiee, N ; Akhavan, O ; Zarrintaj, P ; Hejna, A ; Saeb, M. R ; Zarrabi, A ; Sharifi, E ; Yousefiasl, S ; Zare, E. N ; Sharif University of Technology
John Wiley and Sons Inc
2022
Abstract
A proper self-regenerating capability is lacking in human cardiac tissue which along with the alarming rate of deaths associated with cardiovascular disorders makes tissue engineering critical. Novel approaches are now being investigated in order to speedily overcome the challenges in this path. Tissue engineering has been revolutionized by the advent of nanomaterials, and later by the application of carbon-based nanomaterials because of their exceptional variable functionality, conductivity, and mechanical properties. Electrically conductive biomaterials used as cell bearers provide the tissue with an appropriate microenvironment for the specific seeded cells as substrates for the sake of...
Polyacrylamide-grafted magnetic reduced graphene oxide nanocomposite: preparation and adsorption properties
, Article Colloid and Polymer Science ; 2019 ; 0303402X (ISSN) ; Nazari, M ; Kohestanian, M ; Hosseini, S. H ; Sharif University of Technology
Springer Verlag
2019
Abstract
Magnetic reduced graphene oxide/polymer nanocomposites were prepared by in situ polymerization and grafting of polyacrylamide on the surface of functionalized magnetic reduced graphene oxide (rGO). Graphene oxide nanosheets were decorated with Fe3O4 nanoparticles, reduced and functionalized with 3-(trimethoxysilyl)propyl methacrylate, and then grafted with polyacrylamide. Grafting of polyacrylamide makes magnetic rGO hydrophilic and highly water dispersible. The prepared material was used as adsorbent for removal of an anionic dye, Congo red, and a maximum adsorption capacity up to 166.7 mg g−1 was obtained. The kinetics and isotherm of adsorption and the effect of experimental condition on...
Synthesis of Graphene and Graphene Oxide and It’s Applications for Adsorption of Iodine
, M.Sc. Thesis Sharif University of Technology ; Outokesh, Mohammad (Supervisor) ; Khanchi, Alireza (Supervisor)
Abstract
Graphene is pure carbon in the form of a very thin, nearly transparent sheet, one atom thick. It is remarkably strong for its very low weight. Graphene is a novel particle that can improve adsorption properties. We use graphene for Iodine gas adsorption. Iodine-131 (usually in the chemical form of iodide) is a component of nuclear fallout, and is particularly dangerous owing to the thyroid gland's propensity to concentrate ingested iodine, where it is kept for periods longer than this isotope's radiological half-life of eight days. For this reason, if people are expected to be exposed to a significant amount of environmental radioactive iodine (iodine-131 in fallout), they may be instructed...
Cyto and genotoxicities of graphene oxide and reduced graphene oxide sheets on spermatozoa
, Article RSC Advances ; Vol. 4, issue. 52 , May , 2014 , pp. 27213-27223 ; ISSN: 20462069 ; Akhavan, O ; Shamsara, M ; Rahighi, R ; Esfandiar, A ; Tayefeh, A. R ; Sharif University of Technology
Abstract
Concentration-dependent cyto and genotoxicities of graphene oxide (GO) and reduced GO (rGO) sheets on spermatozoa were studied. rGO sheets with various surface chemical states were achieved using hydrazine (N2H 4) hydrothermal (HT) reactions and green tea polyphenols (GTPs). Although 0.1 μg mL-1 graphene could not change sperm viability and kinetic parameters, <40% and 20% of spermatozoa were viable and progressively motile, after 2 h incubation with 400 μg mL-1 GO or rGO, respectively. All the graphene nanomaterials induced concentration- dependent reductions of adenosine triphosphate and NAD+/NADH produced by spermatozoa for motility and metabolic activity. While GO, N 2H4-rGO, and HT-rGO...
Accelerated differentiation of neural stem cells into neurons on ginseng-reduced graphene oxide sheets
, Article Carbon ; Volume 66 , January , 2014 , Pages 395-406 ; Ghaderi, E ; Abouei, E ; Hatamie, S ; Ghasemi, E ; Sharif University of Technology
Abstract
Asian red ginseng was used for green reduction of chemically exfoliated graphene oxide (GO) into reduced graphene oxide (rGO). The reduction level and electrical conductivity of the ginseng-rGO sheets were comparable to those of hydrazine-rGO ones. Reduction by ginseng resulted in repairing the sp 2 graphitic structure of the rGO, while hydrazine-rGO showed more defects and/or smaller aromatic domains. The ginseng-rGO sheets presented a better stability against aggregation than the hydrazine-rGO ones in an aqueous suspension. Whilst the hydrophobic hydrazine-rGO films exhibited no toxicity against human neural stem cells (hNSCs), the hydrophilic GO and ginseng-rGO films (as more...
Analytical modeling of graphene ribbons as optical circuit elements
, Article IEEE Journal of Quantum Electronics ; Vol. 50, issue. 6 , 2014 , pp. 397-403 ; ISSN: 00189197 ; Rejaei, B ; Sharif University of Technology
Abstract
We demonstrate that graphene ribbons can be modeled as circuit elements, which have dual capacitive-inductive nature. In the subwavelength regime, the surface current density on a single graphene ribbon subject to an incident p-polarized plane wave is derived analytically and then it is extended to coplanar arrays of graphene ribbons by applying perturbation theory. It is demonstrated that even isolated graphene ribbons have capacitive properties and the interaction between them in an array only changes the capacitance. Finally, we propose an accurate circuit model for the ribbon array by applying appropriate boundary conditions