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    Design and Construction of a Sputter Ion Pump

    , M.Sc. Thesis Sharif University of Technology Bazrafshan, Gholamreza (Author) ; Vosoughi, Naser (Supervisor) ; Rahighi, Javad (Supervisor)
    Abstract
    Design and construction process of special kind of sputter ion pump is described briefly in this paper. In order to investigate the optimization of effective parameters in choosing and designing ILSF ion pumps, this pump has been designed and manufactured. By optimizing some parameters such as dimension and shape of penning cells, anode voltage, magnetic field and internal structure of pump, it is possible to significantly decrease the cost of construction and operation of synchrotron vacuum system. By using the results of simulations and calculations of electromagnetic field, plasma simulation or glow discharge, titanium sputtering, etc., critical parameters in design of internal structure... 

    Design and Construction of a Digital Position Encoding System for a Delay Line based Two-dimensional Multi Wire Proportional Detector

    , M.Sc. Thesis Sharif University of Technology Amoozegar, Vahid (Author) ; Vosoughi, Naser (Supervisor) ; Rahighi, Javad (Supervisor)
    Abstract
    In this thesis a digital electronic readout system is designed and constructed for MWPC detector. This detector is aimed to be used in ILSF synchrotron. The detector readout system is based on delay line and position of incoming photon can be underestood from delay of cathode signals arrivals. The detector has two dimentional position detecting system and the instruments used in every dimention are identical. Every dimention has a start and stop signal, the time difference between these two signals can be detected by time to amplitude converter or time to digital converter. In this thesis time to digital converter has been used and the time diference of start and stop signals arrivals is... 

    Toward single-DNA electrochemical biosensing by graphene nanowalls

    , Article ACS Nano ; Volume 6, Issue 4 , March , 2012 , Pages 2904-2916 ; 19360851 (ISSN) Akhavan, O ; Ghaderi, E ; Rahighi, R ; Sharif University of Technology
    2012
    Abstract
    Graphene oxide nanowalls with extremely sharp edges and preferred vertical orientation were deposited on a graphite electrode by using electrophoretic deposition in an Mg 2+-GO electrolyte. Using differential pulse voltammetry (DPV), reduced graphene nanowalls (RGNWs) were applied for the first time, in developing an ultra-high-resolution electrochemical biosensor for detection of the four bases of DNA (G, A, T, and C) by monitoring the oxidation signals of the individual nucleotide bases. The extremely enhanced electrochemical reactivity of the four free bases of DNA, single-stranded DNA, and double-stranded DNA (dsDNA) at the surface of the RGNW electrode was compared to electrochemical... 

    Synthesis of Graphene Nanosheets for Application in Biosensors

    , M.Sc. Thesis Sharif University of Technology Rahighi Yazdi, Reza (Author) ; Akhavan, Omid (Supervisor)
    Abstract
    Graphene, the newborn nanomaterial whose unique properties has extensively drawnattention of many scientists in the recent years, is an ideal candidate for sensing applications due to its exclusive properties like extremely high specific surface area, excellent electrical conductivity, andcapability of being easily functionalized. In this research, after reviewing the attempts already performed on detection of DNA, in order to detect the four bases of DNA (G, A, T, and C) via electrochemical approach, graphene nanosheets were synthesized by the popular Hummer’s method and were deposited on a graphite rod by electrophoretic deposition with a vertical preferred orientation. To eliminate the... 

    Spongy graphene electrode in electrochemical detection of leukemia at single-cell levels

    , Article Carbon ; Vol. 79 , 2014 , pp. 654–663 ; ISSN: 00086223 Akhavan, O ; Ghaderi, E ; Rahighi, R ; Abdolahad, M ; Sharif University of Technology
    2014
    Abstract
    Mg2+-charged spongy graphene electrodes (SGEs) were fabricated by using electrophoretic deposition of chemically exfoliated graphene oxide sheets on graphite rods. The SGEs were able to present two distinguishable signals (originated from electrochemical oxidation of guanine) in differential pulse voltammetry (DPV) of leukemia and normal blood cells, in contrast to glassy carbon electrodes giving only one overlapped peak. Hence, the SGEs were applied in fast (60 min) and ultra sensitive detection of leukemia (single abnormal cells in ∼109 normal cells) in a blood serum. The sensitivity obtained by the SGEs was three orders of magnitude better than that of the best available and current... 

    Ultra-sensitive detection of leukemia by graphene

    , Article Nanoscale ; Vol. 6, issue. 24 , Dec , 2014 , p. 14810-14819 Akhavan, O ; Ghaderi, E ; Hashemi, E ; Rahighi, R ; Sharif Universit of Technology
    2014
    Abstract
    Graphene oxide nanoplatelets (GONPs) with extremely sharp edges (lateral dimensions ∼20-200 nm and thicknesses <2 nm) were applied in extraction of the overexpressed guanine synthesized in the cytoplasm of leukemia cells. The blood serums containing the extracted guanine were used in differential pulse voltammetry (DPV) with reduced graphene oxide nanowall (rGONW) electrodes to develop fast and ultra-sensitive electrochemical detection of leukemia cells at leukemia fractions (LFs) of ∼10-11 (as the lower detection limit). The stability of the DPV signals obtained by oxidation of the extracted guanine on the rGONWs was studied after 20 cycles. Without the guanine extraction, the DPV peaks... 

    Curcumin as a green fluorescent label to revive the fluorescence property of functionalized graphene oxide nanosheets

    , Article Journal of Drug Delivery Science and Technology ; Volume 45 , June , 2018 , Pages 422-427 ; 17732247 (ISSN) Akbari, E ; Akhavan, O ; Hatamie, S ; Rahighi, R ; Sharif University of Technology
    Editions de Sante  2018
    Abstract
    In this work, graphene oxide (GO) aqueous suspensions prepared by a chemical exfoliation method showed a fluorescence peak at ∼615 nm. Photoluminescence spectroscopy determined that functionalization of the GO sheets by 3-(2-Aminoethylamino) propyltrimethoxysilane molecules significantly quench the fluorescence property of the GO sheets. Fourier transform infrared spectroscopy confirmed proper functionalization of the GO sheets. Curcumin was applied as a fluorescent natural material with an emission peak at ∼550 nm wavelength for green fluorescent labeling of the functionalized-GO sheets. The curcumin-labeled functionalized-GO sheets showed an intense emission band fluorescent property with... 

    Pressure-engineered electrophoretic deposition for gentamicin loading within osteoblast-specific cellulose nanofiber scaffolds

    , Article Materials Chemistry and Physics ; Volume 272 , 2021 ; 02540584 (ISSN) Rahighi, R ; Panahi, M ; Akhavan, O ; Mansoorianfar, M ; Sharif University of Technology
    Elsevier Ltd  2021
    Abstract
    Multi-component nanocomposite thin films (composed of cellulose nanofiber (CNF), alginate, bioglass nanoparticles (BG NPs) and gentamicin) were prepared by using cathodic electrophoretic deposition (EPD) under different isostatic pressures of 10−2 mbar (LP), atmospheric (AP), and 5 bar (HP). According to thermal gravity analysis, larger amounts of CNF and alginate could be deposited on the surface at the AP condition in comparison with the LP and HP conditions. On the other hand, higher amounts of the BG NPs could be deposited at the LP condition as compared to the other conditions. The drug (gentamicin) loading/releasing of the samples prepared at the HP condition was found to be higher... 

    A fuzzy random minimum cost network flow programming problem [electronic resource]

    , Article Journal of Industrial and Systems Engineering (JISE)-Iranian Institute of Industrial Engineering ; Article 3, Volume 6, Issue 1, Spring 2012, Page 34-47 Nematian, J. (Javad) ; Eshghi, Kourosh ; Sharif University of Technology
    Abstract
    In this paper, a fuzzy random minimum cost flow problem is presented. In this problem, cost parameters and decision variables are fuzzy random variables and fuzzy numbers respectively. The object of the problem is to find optimal flows of a capacitated network. Then, two algorithms are developed to solve the problem based on Er-expected value of fuzzy random variables and chance-constrained programming. Furthermore, the results of two algorithms will be compared. An illustrative example is also provided to clarify the concept  

    Special classes of mathematical programming models with fuzzy random variables [electronic resource]

    , Article Journal of Intelligent and Fuzzy Systems, Published In: IOS Press ; Volume 19, Number 2, 2008 Eshghi, K. (Kourosh) ; Nematian, Javad ; Sharif University of Technology
    Abstract
    In this paper, we will discuss two special classes of mathematical programming models with fuzzy random variables. In the first model, a linear programming problem with fuzzy decision variables and fuzzy random coefficients is introduced. Then an algorithm is developed to solve the model based on fuzzy optimization method and fuzzy ranking method. In the second model, a fuzzy random quadratic spanning tree problem is presented. Then the proposed problem is formulated and solved by using the scalar expected value of fuzzy random variables. Furthermore, illustrative numerical examples are also given to clarify the methods discussed in this paper  

    A special class of fuzzy integer programming model with all different constraints [electronic resource]

    , Article Scientia Iranica ; Vol. 16, No. 1, pp. 1-10, 2009 Eshghi, K. (Kourosh) ; Nematian, Javad ; Sharif University Of Technology
    Abstract
    In this paper, a fuzzy approach is applied to special classes of integer programming problems with all diierent constraints. In the rst model, a fuzzy integer programming model is developed to represent the all-diierent constraints in mathematical programming. In order to solve the proposed model, a new branching scheme for the Branch and Bound algorithm is also presented. In the second model, a special class of large-scale multi-objective fuzzy integer programming problems with all-diierent constraints is introduced. A solution method for the proposed model is also developed by using the decomposition technique, weighting method and Branch and Bound algorithm. An illustrative numerical... 

    Fuzzy random minimum cost network problem [electronic resource]

    , Article Journal of Industrial and Systems Engineering ; Vol. 6, No. 1, pp 34-47, 2012 Nematian, J. (Javad) ; Eshghi, Kourosh ; Sharif University of Technology
    Abstract
    In this paper, a fuzzy random minimum cost flow problem is presented. In this problem, cost parameters and decision variables are fuzzy random variables and fuzzy numbers respectively. The object of the problem is to find optimal flows of a capacitated network. Then, two algorithms are developed to solve the problem based on Er-expected value of fuzzy random variables and chance-constrained programming. Furthermore, the results of two algorithms will be compared. An illustrative example is also provided to clarify the concept  

    Rolled graphene oxide foams as three-dimensional scaffolds for growth of neural fibers using electrical stimulation of stem cells

    , Article Carbon ; Volume 97 , 2016 , Pages 71-77 ; 00086223 (ISSN) Akhavan, O ; Ghaderi, E ; Shirazian, S. A ; Rahighi, R ; Sharif University of Technology
    Elsevier Ltd  2016
    Abstract
    Graphene oxide foam (GOF) layers with thicknesses of ∼15-50 μm and density of ∼10 graphene oxide (GO) sheets/μm were fabricated by precipitation of chemically exfoliated GO sheets in an aqueous suspension at ∼80 °C under UV irradiation. Then, rolled GOFs with desirable scales were developed as electrically conductive 3D-scaffolds and applied in directional growth of neural fibers, through differentiation of human neural stem cells (hNSCs) into neurons under an electrical stimulation. X-ray photoelectron spectroscopy indicated that the UV irradiation resulted in partial deoxygenation of the layers. Scanning electron microscopy and Raman spectroscopy confirmed the presence of multilayer GO... 

    DNA and RNA extractions from eukaryotic and prokaryotic cells by graphene nanoplatelets

    , Article RSC Advances ; Vol. 4, issue. 105 , 2014 , p. 60720-60728 Hashemi, E ; Akhavan, O ; Shamsara, M ; Valimehr, S ; Rahighi, R ; Sharif University of Technology
    2014
    Abstract
    Graphene nanoplatelets with lateral dimensions of ∼50-200 nm and thicknesses <2 nm were utilized for the extraction of nucleic acids (NAs) from eukaryotic and prokaryotic cells. The graphene nanoplatelets (both chemically exfoliated graphene oxide nanoplatelets and hydrazine-reduced graphene oxide nanoplatelets) successfully extracted plasmid DNA (pDNA) from Escherichia coli bacteria, comparable to a conventional phenol-chloroform (PC) method. Furthermore, it was found that the yield of graphene nanoplatelets in genomic DNA (gDNA) and RNA extractions from embryonic stem cells (ESCs) was also comparable to the yield of the conventional methods. The effects of the graphene nanoplatelets on... 

    Novel aspects of application of cadmium telluride quantum dots nanostructures in radiation oncology

    , Article Applied Physics A: Materials Science and Processing ; Volume 123, Issue 8 , 2017 ; 09478396 (ISSN) Fazaeli, Y ; Zare, H ; Karimi, S ; Rahighi, R ; Feizi, S ; Sharif University of Technology
    Springer Verlag  2017
    Abstract
    In the last two decades, quantum dots nanomaterials have garnered a great deal of scientific interest because of their unique properties. Quantum dots (QDs) are inorganic fluorescent nanocrystals in the size range between 1 and 20 nm. Due to their structural properties, they possess distinctive properties and behave in different way from crystals in macro scale, in many branches of human life. Cadmium telluride quantum dots (CdTe QDs) were labeled with 68Ga radio nuclide for fast in vivo targeting and coincidence imaging of tumors. Using instant paper chromatography, the physicochemical properties of the Cadmium telluride quantum dots labeled with 68Ga NPs (68Ga@ CdTe QDs) were found high... 

    Evaluation of dosimetric characteristics of graphene oxide/PVC nanocomposite for gamma radiation applications

    , Article Radiochimica Acta ; Volume 105, Issue 2 , 2017 , Pages 161-170 ; 00338230 (ISSN) Feizi, S ; Malekie, S ; Rahighi, R ; Tayyebi, A ; Ziaie, F ; Sharif University of Technology
    Walter de Gruyter GmbH  2017
    Abstract
    Graphene oxide-polyvinyl chloride composite was prepared using tetrahydrofuran solvent-assisted dispersion of characterized nano flakes of graphene oxide in polymer matrix. Electrical percolation threshold of GO/PVC nanocomposite was determined via a finite element simulation method with a 2D model and compared with experimental results. A conductive cell with two silver coated walls was designed and fabricated for exploring dosimetric properties of the composite. Some characteristics of the new nanocomposite such as linearity of dose response, repeatability, sensitivity and angular dependence are investigated. According to 2D proposed method, obtained data associated to electrical... 

    Synthesis of magnetic ions-doped QDs Synthesized Via a facial aqueous solution method for Optical/MR dual-modality imaging applications

    , Article Journal of Fluorescence ; Volume 31, Issue 3 , 2021 , Pages 897-906 ; 10530509 (ISSN) Gharghani, S ; Zare, H ; Shahedi, Z ; Fazaeli, Y ; Rahighi, R ; Sharif University of Technology
    Springer  2021
    Abstract
    This research reports the preparation and examination of Cadmium Telluride (CdTe) Quantum Dots and doping CdTe QDs with Europium (Eu), Gadolinium (Gd), and Manganese (Mn) prepared in aqueous solution using TGA as a capping agent. Magnetic QDs (MQDs) are important agents for fluorescence (FL) /magnetic resonance (MR) dual-modal imaging due to their excellent optical and magnetic properties. Herein, the chemical bonds, structural, fluorescence, and magnetized properties of CdTe QDs and effect of Mn, Eu, and Gd ions doping on their properties were examined by X-ray powder diffraction (XRD), high-resolution transmission electron microscopy (HRTM), Energy-dispersive X-ray spectroscopy (EDX),... 

    Ultrafast and stable planar photodetector based on SnS2 nanosheets/perovskite structure

    , Article Scientific Reports ; Volume 11, Issue 1 , 2021 ; 20452322 (ISSN) Shooshtari, L ; Esfandiar, A ; Orooji, Y ; Samadpour, M ; Rahighi, R ; Sharif University of Technology
    Nature Research  2021
    Abstract
    Two-dimensional (2D) transition metal dichalcogenides are promising candidates of photodetectors where they are commonly grown parallel to the substrate due to their 2D characteristics in micrometer scales from exfoliation of bulk crystals or through high temperature chemical vapor deposition (CVD) methods. In this study, semi-hexagonal vertical nanosheets of SnS2 layered have been fabricated on FTO substrate without using Sn source through CVD method at relatively low temperature (500 °C). Due to exceptional band alignment of triple cation lead perovskite (TCLP) with semi-hexagonal SnS2 nanosheets, an improved photodetector has been fabricated. This type of photodetectors fabricated through... 

    All-Carbon negative differential resistance nanodevice using a single flake of nanoporous graphene

    , Article ACS Applied Electronic Materials ; Volume 3, Issue 8 , 2021 , Pages 3418-3427 ; 26376113 (ISSN) Rahighi, R ; Akhavan, O ; Shayesteh Zeraati, A ; Sattari Esfahlan, S. M ; Sharif University of Technology
    American Chemical Society  2021
    Abstract
    A temperature-induced degenerate p-type graphene nanopore/reduced graphene oxide (GNP/rGO) heterojunction-based nanodevice was prepared and studied for the first time, showing a robust negative differential resistance (NDR) feature. In this regard, cellulose-based perforated graphene foams (PGFs), containing numerous nanopores (with an average size of ∼2 nm surrounded by nearly six-layer rGO walls) were synthesized using bagasse as a green starting material. The PGFs with an essential p-type semiconducting property showed a band gap energy of ∼1.8 eV. The observed two-terminal NDR peak could present stable and reversible features at high temperatures of 586-592 K. It was demonstrated that... 

    Production of Uranium Dioxide Nano Powder With Hydrothermal Method in Supercritical Water Reactor

    , M.Sc. Thesis Sharif University of Technology Golzary, Abooali (Author) ; Outokesh, Mohammad (Supervisor) ; Ahmadi, Javad (Supervisor) ; Karimi Sabet, Javad (Co-Advisor)
    Abstract
    Hydrothermal supercritical method is one of the most suitable methods for metal oxide nano powder, ceramics and mineral catalyst synthesis. Metal oxides nanopowder in its pure or mixed form has wide potential application as chemical industrial catalyst, hot Superconductors, magnetic material, gas sensors and car catalyst convertors. One of the most important metal oxides aspects of application is uranium oxide as nuclear reactor fuel is used. In addition, UO2 is selective catalyst for converting methane to methanol process and Decomposition of organic Chlorine material. In Supercritical hydrothermal method done in high pressure reactor with critical to fluid, is new method for the...