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    One-step fabrication of electrochemically reduced graphene oxide/nickel oxide composite for binder-free supercapacitors

    , Article International Journal of Hydrogen Energy ; Volume 41, Issue 39 , 2016 , Pages 17496-17505 ; 03603199 (ISSN) Shahrokhian, S ; Mohammadi, R ; Asadian, E ; Sharif University of Technology
    Elsevier Ltd  2016
    Abstract
    A three-dimensional (3D) graphene/Nickel oxide (ERGO/NiO) composite electrode have been fabricated directly on a Nickel foam substrate via a one-step electrochemical co-deposition in an aqueous solution containing Nickel nitrate and GO. By using this simple and one-step electrochemical deposition, it is possible to produce binder-free composite electrodes with improved electrochemical properties using a low-cost, facile and scalable technique. It is observed from FE-SEM images that graphene oxide sheets affect the electrodeposition of nickel oxide. The optimized ErGO/NiO electrode developed in this work exhibits high charge storage capacity with a specific capacitance of 1715.5 F g−1 at... 

    In-situ electro-polymerization of graphene nanoribbon/polyaniline composite film: Application to sensitive electrochemical detection of dobutamine

    , Article Sensors and Actuators, B: Chemical ; Vol. 196 , June , 2014 , pp. 582-588 ; ISSN: 09254005 Asadian, E ; Shahrokhian, S ; Zad, A. I ; Jokar, E ; Sharif University of Technology
    2014
    Abstract
    The present paper demonstrates the capability of narrow graphene nanoribbons (GNRs) in constructing new sensing platforms. Graphene nanoribbons have been synthesized via a simple solvothermal route through unzipping of carbon nanotubes, which was confirmed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectroscopy analysis. These narrow carbon sheets were used to form a composite film by in-situ electro-polymerization with aniline. The produced graphene nanoribbon/polyaniline (GNR/PANI) composite film showed impressive performance in electrochemical determination of dobutamine (DBT). Under optimal conditions, in comparison to... 

    Improvement in mechanical performance of anionic hydrogels using full-interpenetrating polymer network reinforced with graphene oxide nanosheets

    , Article Advances in Polymer Technology ; Volume 35, Issue 4 , 2016 , Pages 386-395 ; 07306679 (ISSN) Kheirabadi, M ; Bagheri, R ; Kabiri, K ; Ossipov, D. A ; Jokar, E ; Asadian, E ; Sharif University of Technology
    John Wiley and Sons Inc  2016
    Abstract
    Weak mechanical possession is one of the limiting factors in application of hydrogels. To modify this inherent disadvantage, different approaches have been studied including synthesizing interpenetrating polymer network (IPN) and nanocomposite hydrogels. So, this study has focused on preparation of a novel full-IPN structure based on anionic monomers of 2-acrylamido-2-methylpropane sulfonic acid/acrylic acid–sodium acrylate via facile solution polymerization technique in an aqueous media with incorporation of graphene oxide (GO) nanosheets. Mechanical performance of materials in the “as-prepared condition” and “swollen state” was characterized via tensile, compression, and rheology tests,... 

    Improvement in mechanical performance of anionic hydrogels using full-interpenetrating Polymer Network Reinforced with Graphene Oxide Nanosheets

    , Article Advances in Polymer Technology ; 2015 ; 07306679 (ISSN) Kheirabadi, M ; Bagheri, R ; Kabiri, K ; Ossipov, D. A ; Jokar, E ; Asadian, E ; Sharif University of Technology
    John Wiley and Sons Inc  2015
    Abstract
    Weak mechanical possession is one of the limiting factors in application of hydrogels. To modify this inherent disadvantage, different approaches have been studied including synthesizing interpenetrating polymer network (IPN) and nanocomposite hydrogels. So, this study has focused on preparation of a novel full-IPN structure based on anionic monomers of 2-acrylamido-2-methylpropane sulfonic acid/acrylic acid-sodium acrylate via facile solution polymerization technique in an aqueous media with incorporation of graphene oxide (GO) nanosheets. Mechanical performance of materials in the "as-prepared condition" and "swollen state" was characterized via tensile, compression, and rheology tests,... 

    Silver nanowires immobilized on gold-modified glassy carbon electrode for electrochemical quantification of atorvastatin

    , Article Journal of Electroanalytical Chemistry ; Volume 876 , November , 2020 Naseri, A ; Hormozi Nezhad, M. R ; Shahrokhian, S ; Asadian, E ; Sharif University of Technology
    Elsevier B.V  2020
    Abstract
    Development of simple yet precise sensing platforms for rapid determination of biological species and drugs is of paramount importance, not only for analysis of pharmaceutical formulations during the production stage, but also in clinical practices and medical diagnosis. In the present research, we report on the electrochemical determination of atorvastatin (ATOR) by using silver nanowires/gold-modified glassy carbon electrode (Ag NWs/Au/GCE). The modified electrode was constructed through a two-step procedure in which narrow silver nanowires synthesized via a polyol method are drop casted on a pre-modified GCE with electrodeposited gold particles. The results of XRD analysis indicated the... 

    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) Ejehi, F ; 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... 

    Self-powered ultraviolet/visible photodetector based on graphene-oxide via triboelectric nanogenerators performing by finger tapping

    , Article Nanotechnology ; Volume 33, Issue 47 , 2022 ; 09574484 (ISSN) Ejehi, F ; Shooshtari, L ; Mohammadpour, R ; Asadian, E ; Sasanpour, P ; Sharif University of Technology
    Institute of Physics  2022
    Abstract
    Self-sufficient power sources provide a promising application of abundant electronic devices utilized in detection of ambient properties. Recently, triboelectric nanogenerators (TENGs) have been widely investigated to broaden the self-powered systems by converting the ambient mechanical agitations into electrical voltage and current. Graphene oxide (GO), not only for sensing applications but also as a brilliant energy-related nanomaterial, provides a wide range of controllable bandgap energies, as well as facile synthesis route. In this study, GO-based self-powered photodetectors have been fabricated by conflating the photosensitivity and triboelectric characteristics of freestanding GO... 

    An efficient two-step approach for improvement of graphene aerogel characteristics in preparation of supercapacitor electrodes

    , Article Journal of Energy Storage ; Volume 17 , 2018 , Pages 465-473 ; 2352152X (ISSN) Jokar, E ; Shahrokhian, S ; zad, A. I ; Asadian, E ; Hosseini, H ; Sharif University of Technology
    Elsevier Ltd  2018
    Abstract
    We fabricated a high rate capability supercapacitor based on fluorine-doped graphene-carbon nanotubes aerogel network (G-CNT-F). Based on the electrochemical impedance spectroscopy data, the fluorination decreases the charge transfer resistance of graphene sheets, while CNTs act as spacer in the 3D structure. Therefore, both treatments improved the electrochemical properties of the resulted aerogel. Based on the Fourier transform infrared spectroscopy and XPS results, these excellent performances are attributed to semi-ionic bonds between fluorine and carbon. The specific capacitance of the graphene aerogel showed 78% decrease, when discharge current increases from 2 to 40 mA, while the... 

    Graphene oxide papers in nanogenerators for self-powered humidity sensing by finger tapping

    , Article Scientific Reports ; Volume 10, Issue 1 , 2020 Ejehi, F ; Mohammadpour, R ; Asadian, E ; Sasanpour, P ; Fardindoost, S ; Akhavan, O ; Sharif University of Technology
    Nature Research  2020
    Abstract
    Triboelectric nanogenerators (TENGs) offer an emerging market of self-sufficient power sources, converting the mechanical energy of the environment to electricity. Recently reported high power densities for the TENGs provide new applications opportunities, such as self-powered sensors. Here in this research, a flexible graphene oxide (GO) paper was fabricated through a straightforward method and utilized as the electrode of TENGs. Outstanding power density as high as 1.3 W.m−2, an open-circuit voltage up to 870 V, and a current density of 1.4 µA.cm−2 has been extracted in vertical contact-separation mode. The all-flexible TENG has been employed as a self-powered humidity sensor to... 

    A computational modelling study of excitation of neuronal cells with triboelectric nanogenerators

    , Article Scientific Reports ; Volume 12, Issue 1 , 2022 ; 20452322 (ISSN) Nazari Vanani, R ; Mohammadpour, R ; Asadian, E ; Rafii-Tabar, H ; Sasanpour, P ; Sharif University of Technology
    Nature Research  2022
    Abstract
    Neurological disorders and nerve injuries, such as spinal cord injury, stroke, and multiple sclerosis can result in the loss of muscle function. Electrical stimulation of the neuronal cells is the currently available clinical treatment in this regard. As an effective energy harvester, the triboelectric nanogenerators (TENG) can be used for self-powered neural/muscle stimulations because the output of the TENG provides stimulation pulses for nerves. In the present study, using a computational modelling approach, the effect of surface micropatterns on the electric field distribution, induced voltage and capacitance of the TENG structures have been investigated. By incorporating the effect of... 

    Low cost flexible pressure sensor using laser scribed GO/RGO periodic structure for electronic skin applications

    , Article Superlattices and Microstructures ; Volume 140 , 2020 Hosseindokht, Z ; Mohammadpour, R ; Asadian, E ; Paryavi, M ; Rafii Tabar, H ; Sasanpour, P ; Sharif University of Technology
    Academic Press  2020
    Abstract
    Considering electronic skin applications, a pressure sensor based on periodic structure of graphene oxide-reduced graphene oxide (GO-rGO) has been designed and fabricated based on a low cost direct laser writing technique by utilizing the laser diode of DVD drive's pickup head. The optimization of sensor structure has been performed using computational modelling through Finite Element Method (FEM) in the COMSOL environment. The optimized structure is fabricated based on the deposition of thin layer of GO on the surface of Kapton and the pattering is performed by laser irradiation. The fabricated sensor structure has been characterized structurally and functionally. The results show that the... 

    Room temperature and high response ethanol sensor based on two dimensional hybrid nanostructures of WS2/GONRs

    , Article Scientific Reports ; Volume 10, Issue 1 , 2020 Ahmadvand, H ; Iraji zad, A ; Mohammadpour, R ; Hosseini Shokouh, S. H ; Asadian, E ; Sharif University of Technology
    Nature Research  2020
    Abstract
    Here in this research, room temperature ethanol and humidity sensors were prepared based on two dimensional (2D) hybrid nanostructures of tungsten di-sulfide (WS2) nanosheets and graphene oxide nanoribbons (GONRs) as GOWS. The characterization results based on scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (ESD), Raman spectroscopy and X-ray diffraction (XRD) analysis confirmed the hybrid formations. Ethanol sensing of drop-casted GOWS films on SiO2 substrate indicated increasing in gas response up to 5 and 55 times higher compared to pristine GONRs and WS2 films respectively. The sensing performance of GOWS hybrid nanostructures was investigated in different... 

    Multiobjective Earth-Moon Trajectory Optimization in the Restricted Four-Body Problem

    , Ph.D. Dissertation Sharif University of Technology Asadian, Nima (Author) ; Pourtakdoust, Hossein (Supervisor)
    Abstract
    Outer space mission design utilizing restricted four-body model for spacecrafts equipped with impulsive engines is investigated. Applied researches in the field of space mission design are typically based on two-body models and in some more advanced cases involve application of the restricted three-body models. As the general solution of the two-body problem is known (conic sections), the transfer trajectories are generally designed using simple Hohmann transfers. But, when considering three-body problem, there is no closed-form solution and low-energy transfer trajectories are designed through the use of stable/unstable manifolds of the corresponding halo orbits. In this way, some... 

    Chemically Modified Electrodes Based on Conducting Polymers and Carbon Nanotubes: Application to Voltammetric Determination of Some Biological and Pharmaceutical Compounds

    , M.Sc. Thesis Sharif University of Technology Asadian, Elham (Author) ; Shahrokhian, Saeed (Supervisor)
    Abstract
    There are high attractions in the development of conducting polymer (CP) coatings to improve the electrochemical properties and biocompatibility of electrodes in the area of biosensors. In the first part of this thesis, a new type of modified electrodes, constructing multi-walled carbon nanotubes (MWCNTs) and polypyrrole is prepared in a layer-by-layer process. In this procedure, the glassy carbon electrode is casted first by a drop suspension of MWCNTs, leading to formation a thin film on its surface. In the second step, electrochemical polymerization of pyrrole in the presence of tiron (used as doping anion) is performed on the surface of the MWCNTs pre-coated electrode. The modification... 

    Autonomous Orbit Estimation for Regional Navigation Satellites

    , M.Sc. Thesis Sharif University of Technology Memaran, Mohsen (Author) ; Asadian, Nima (Supervisor)
    Abstract
    In this thesis, autonomous orbit estimation of regional navigation satellites has been investigated. Estimation of satellite orbit is an integral part of satellite navigation, which may be executed via assistance of ground station. As the satellite is exposed to the ground station view, range, direction and rate of range is measured by mean of ranging instrumentation relative to ground reference, hence the precise position is calculated. In this thesis a set of satellites are investigated in a unique structure called constellation with the purpose of navigation. The occurrence which is likely to happen in this condition, is the failure of ground station under certain circumstances or losing... 

    Fault-tolerant Attitude Control of Sattelite Using Neural Networks

    , M.Sc. Thesis Sharif University of Technology Sepehr, Firoozeh (Author) ; Asadian, Nima (Supervisor)
    Abstract
    This research aims to introduce a new integrated fault tolerant attitude control system of satellites based on the neural networks. First, a linear controller and an optimal controller are designed assuming that no fault occurs in the reaction wheels of the satellite. It is obvious that these controllers are not able to respond properly when a fault occurs. Therefore, artificial neural networks are employed in the fault tolerant controller design. Neural networks are well-known for their adaptiveness and the ability to learn the dynamics of a system. Therefore, they can be used to predict the faulty conditions. In this research two approaches are examined to deal with the faulty conditions.... 

    Continuous-thrust Trajectory Optimization in the Binary Asteroids System

    , M.Sc. Thesis Sharif University of Technology Ashrafi, Mehnraz (Author) ; Asadian, Nima (Supervisor)
    Abstract
    In this thesis, the optimal trajectories of a spacecraft in the binary asteroids system is studied. The objective functions of optimal trajectories in these system are the maximum coverage of the asteroids surface and minimum time and fuel consumption. For this purpose, the dynamic of binary system is modeled. The binary system of 1999 KW4 is selected as a case study. The ellipsoid-sphere model is a good approximation for the case of this study. In this model, the asteroids orbit in a circular orbit around each other in a spin-spin-orbit resonance configuration, in which the asteroids’ rotational velocity is equal to orbital mean motion. Then, the equations of motion of the spacecraft as the... 

    Attitude and Deformation Estimation of Flexible Satellite Using Magnetometer and Sun Sensor

    , M.Sc. Thesis Sharif University of Technology Ghani, Marzieh (Author) ; Asadian, Nima (Supervisor)
    Abstract
    The estimation of attitude and deformation of a flexible satellite using magnetometer and sun sensor data are studied in this thesis. To this end, the dynamical differential equations of the flexible satellite have been derived using Lagrange’s equation. These equations of motion are then utilized for the purpose of simulation and verification. After introducing the measurements equations, the observability of the satellite with flexible panels has been evaluated. Afterward, the attitude of the satellite body and deformation of the flexible panels have been estimated by EKF (Extended Kalman Filter) as well as UKF (Unscented Kalman Filter). The results show that the estimations using UKF are... 

    Fault Tolerant Model Predictive Control of Tethered Satellite System

    , M.Sc. Thesis Sharif University of Technology Ramezani, Mahya (Author) ; Asadian, Nima (Supervisor)
    Abstract
    In this thesis, a control method to cope with the fault in the two-satellite two-tether satellite systems has been proposed to avoid failing the mission in the case one tether is torn. A new model for the tethered satellite system with two tethers has been developed to show the effects of tethers’ tension forces in the attitude dynamics. One of the main features of this model is the ability of changing the tethers’ connection points to the co-satellite for attitude control purposes. As a result, tethers’ tension forces are used as control actions to reduce the fuel consumption. The introduced coupled tethered satellite system has been controlled using the model predictive control method.... 

    Spacecraft Rendezvous and Docking Using Adaptive Neuro-Fuzzy Inference System

    , M.Sc. Thesis Sharif University of Technology Tallebi, Morteza (Author) ; Asadian, Nima (Supervisor)
    Abstract
    In this research an ANFIS controller will be developed to rendezvous and dock with a non-cooperative spacecraft; the controller must make the spacecraft reach the velocity and nearby position of the target spacecraft. Due to uncertainty in modeling and changes in the moment inertia tensor, the controller must be able to adapt with these changes and uncertainty, these changes may happen because of robotic arm or solar panel movings. Robustness of the controller will be evaluated by applying orbital disturbances and modeling errors through monte-carlo simulations. To model the spacecraft the specifications of a known spacecraft will be used but some specifications may be studied parametricaly....