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    Magnetic nanoparticles entrapped in the cross-linked poly(imidazole/imidazolium) immobilized Cu(ii): An effective heterogeneous copper catalyst

    , Article RSC Advances ; Volume 4, Issue 87 , 2014 , Pages 46418-46426 ; ISSN: 20462069 Pourjavadi, A ; Hosseini, S. H ; Zohreh, N ; Bennett, C ; Sharif University of Technology
    2014
    Abstract
    Anchoring of copper sulfate in layered poly(imidazole-imidazolium) coated magnetic nanoparticles provided a highly stable, active, reusable, high loading, and green catalyst for the click synthesis of 1,2,3-triazoles via a one-pot cycloaddition of alkyl halide, azide, and alkyne (Cu-A3C). The catalyst was characterized by FTIR, TGA, TEM, SEM, XRD, EDAX, VSM and AAS. High selectivity, broad diversity of alkyl/benzyl bromide/chloride and alkyl/aryl terminal alkynes, and good to excellent yields of products were obtained using 0.7 mol% catalyst. The catalyst was readily recovered and reused up to 6 times without significant loss of activity  

    Covalent immobilization of cellulase using magnetic poly(ionic liquid) support: improvement of the enzyme activity and stability

    , Article Journal of Agricultural and Food Chemistry ; Volume 66, Issue 4 , 2018 , Pages 789-798 ; 00218561 (ISSN) Hosseini, H ; Hosseini, A ; Zohreh, N ; Yaghoubi, M ; Pourjavadi, A ; Sharif University of Technology
    American Chemical Society  2018
    Abstract
    A magnetic nanocomposite was prepared by entrapment of Fe3O4 nanoparticles into the cross-linked ionic liquid/epoxy type polymer. The resulting support was used for covalent immobilization of cellulase through the reaction with epoxy groups. The ionic surface of the support improved the adsorption of enzyme, and a large amount of enzyme (106.1 mg/g) was loaded onto the support surface. The effect of the presence of ionic monomer and covalent binding of enzyme was also investigated. The structure of support was characterized by various instruments such as FT-IR, TGA, VSM, XRD, TEM, SEM, and DLS. The activity and stability of immobilized cellulase were investigated in the prepared support. 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
    Abstract
    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... 

    Synthesis & Properties of Nd-doped Glass-ceramics in the SiO2-CaO-MgO System from Sol-gel Method Used as Solid Lasers

    , M.Sc. Thesis Sharif University of Technology Eslami, Masoud (Author) ; Hamnabard, Zohreh (Supervisor) ; Nemati, Ali (Supervisor)
    Abstract
    In this study, SiO2-CaO-MgO galsses and glass-ceramic powder doped with Nd3+ were synthesized with sol-gel method. Tetraethylorthosilicate (TEOS), Ca(NO3)2.4H2O, Mg(NO3)2.6H2O, Nd(NO3)3.6H2O, ethanol, distilled water, and HNO3 were used as starting materials. The synthesized powder’s properties were examined with STA, XRD, DRS, PL, FTIR and SEM analysis. From XRD patterns of glass samples, the role of dopant was introduced as intermediate oxide in glass matrix. The XRD patterns of glass-ceramic samples indicated that the bredigite and akermanite crystals were formed in glass matrix. The band gap energy of samples were calculated from DRS analysis and were seen with increasing the dopant... 

    Cross-linked poly (dimethylaminoethyl acrylamide) coated magnetic nanoparticles: a high loaded, retrievable, and stable basic catalyst for the synthesis of benzopyranes in water

    , Article RSC Advances ; Vol. 4, issue. 91 , 2014 , p. 50047-50055 Zohreh, N ; Hosseini, S. H ; Pourjavadi, A ; Bennett, C ; Sharif University of Technology
    2014
    Abstract
    A novel heterogeneous catalyst has been synthesized based on the distillation-precipitation-polymerization of methyl acrylate onto modified magnetic nanoparticles followed by the amidation of the methyl ester groups using N,N-dimethylethylenediamine. The resulting poly(dimethylaminoethyl acrylamide) coated magnetic nanoparticles (MNP@PDMA) catalyst was characterized using an array of sophisticated analytical techniques, including FT-IR, TGA, SEM, TEM, CHN, vibrating sample magnetometer (VSM), and XRD analysis. The resulting heterogeneous base catalyst allowed the performance of a domino Knoevenagel condensation/Michael addition/cycloaddition reaction toward the synthesis of... 

    Rating EFL Learner's Interlanguag Pragmatic Competence by Native and Non-native English Speaking Teachers

    , M.Sc. Thesis Sharif University of Technology Rezanejad, Atefeh (Author) ; Alemi, Minoo (Supervisor) ; Eslami Rasekh, Zohreh (Co-Advisor)
    Abstract
    Pragmatic assessment and consistency in rating are among the subject matters which are still in need of more in-depth investigations. The significance of the issue is highlighted when remembering that inconsistency in ratings would surely damage the test fairness issue in assessment and lead to much diversity in ratings. The purpose of this study was investigating the criteria that native (American) and non-native (Iranian) English speaking teachers considered while rating the pragmatic productions of Iranian EFL learners regarding the two speech acts of compliment and compliment response. Overall, a hundred and twenty teachers (sixty native and sixty non-native raters) participated in this... 

    Immobilized copper(II) on nitrogen-rich polymer-entrapped Fe3O4 nanoparticles: A highly loaded and magnetically recoverable catalyst for aqueous click chemistry

    , Article Applied Organometallic Chemistry ; Volume 30, Issue 2 , 2016 , Pages 73-80 ; 02682605 (ISSN) Zohreh, N ; Hosseini, S. H ; Pour Javadi, A ; Bennett, C ; Sharif University of Technology
    John Wiley and Sons Ltd  2016
    Abstract
    A heterogeneous magnetic copper catalyst was prepared via anchoring of copper sulfate onto multi-layered poly(2-dimethylaminoethyl acrylamide)-coated magnetic nanoparticles and was characterized using various techniques. The catalyst was found to be active, effective and selective for one-pot three-component reaction of alkyl halide, sodium azide and alkyne, known as copper-catalyzed click synthesis of 1,2,3-triazoles. As little as 0.3 mol% of catalyst was found to be effective under the optimum conditions. The catalyst could also be recycled and reused up to seven times without significant loss of activity. Thermal stability, high loading level of copper on catalyst, broad diversity of... 

    Immobilized tungstate on magnetic poly(2-ammonium ethyl acrylamide): A high loaded heterogeneous catalyst for selective oxidation of sulfides using H2O2

    , Article Journal of Industrial and Engineering Chemistry ; Volume 44 , 2016 , Pages 73-81 ; 1226086X (ISSN) Zohreh, N ; Hosseini, S. H ; Pourjavadi, A ; Soleyman, R ; Bennett, C ; Sharif University of Technology
    Korean Society of Industrial Engineering Chemistry  2016
    Abstract
    A heterogeneous tungstate-based catalyst has been prepared for selective oxidation of sulfides to sulfoxides in the presence of 30% H2O2. The catalyst was prepared via immobilization of high amounts of WO4 2− onto the cross-linked poly(ammonium ethyl acrylamide) coated magnetic nanoparticles (MNP). FT-IR, TEM, TGA, VSM, XRD, EDX, and CHN analysis were used for characterization of catalyst. Variety of sulfides successfully converted to the related sulfoxides using 1 mol% of catalyst at room temperature in high yields. The catalyst was easily recovered and reused up to 6 times without loss of activity  

    Tungstate-loaded triazine-based magnetic poly(Bis-imidazolium ionic liquid): An effective bi-functional catalyst for tandem selective oxidation/Knoevenagel condensation in water

    , Article Polymer (United Kingdom) ; Volume 112 , 2017 , Pages 342-350 ; 00323861 (ISSN) Zohreh, N ; Tavakolizadeh, M ; Hosseini, S. H ; Pourjavadi, A ; Bennett, C ; Sharif University of Technology
    Elsevier Ltd  2017
    Abstract
    A novel bi-functional polymeric catalyst was synthesized by immobilization of tungstate anions onto the nitrogen rich poly(ionic liquid)/magnetic nanocomposite. The resulting catalyst has two types of catalytic sites: (i) immobilized WO4 anions with bis-imidazolium ionic liquid cation for selective oxidation of alcohols and (ii) basic amine groups for Knoevenagel condensation between produced aldehyde and malononitrile. Due to the polymeric nature of the catalyst, large amounts of tungstate and basic nitrogen groups were presented on the solid surface which led to a decrease in the applied catalyst mass for catalytic reaction. High catalytic activity and excellent selectivity of catalyst in... 

    Highly dispersible bis-imidazolium/WO4 2 modified magnetic nanoparticles: a heterogeneous phase transfer catalyst for green and selective oxidations

    , Article New Journal of Chemistry ; Volume 40, Issue 12 , 2016 , Pages 10325-10332 ; 11440546 (ISSN) Zohreh, N ; Tavakolizadeh, M ; Hosseini, S. H ; Jahani, M ; Pourjavadi, A ; Bennett, C ; Sharif University of Technology
    Royal Society of Chemistry  2016
    Abstract
    A novel magnetically recoverable catalyst was prepared in which magnetic nanoparticles (MNPs) were functionalized by bis-imidazolium tungstate ionic liquid molecules. The resulting catalyst was highly dispersible in water and selectively oxidized a wide range of alcohols and sulfides using H2O2 as a green oxidant. The catalyst was easily recovered and reused at least 5 times under the described reaction conditions without any significant loss of reactivity  

    Recent activities in science and technology and the progress of women in physics in the last three years in Iran

    , Article AIP Conference Proceedings, Stellenbosch ; Volume 1517 , 2013 , Pages 108-109 ; 0094243X (ISSN); 9780735411388 (ISBN) Izadi, D ; Azad, M. T ; Mahmoudi, N ; Izadipanah, N ; Eshghi, N ; Sharif University of Technology
    2013
    Abstract
    For the 4th IUPAP International Conference of Women in Physics, we report on activities in science and engineering in Iran, and conditions for women in physics, in the three years since the 3rd IUPAP International Conference of Women in Physics was held in 2008. Iran has made prominent advancements and astonishing progress in laser technology, biotechnology, nanotechnology, genetics, computer software and hardware, and robotics. Iranian scientists have been very productive in several experimental fields, such as pharmaceutical, organic, and polymer chemistry. Conditions for women in physics have improved greatly in recent years. A project to improve the environment for learning physics, and... 

    Ab initio study of electronic effects in the ZnO/TiO2 core/shell interface: Application in dye sensitized solar cells

    , Article RSC Advances ; Vol. 4, issue. 1 , April , 2014 , p. 301-307 Pazoki, M ; Nafari, N ; Taghavinia, N ; Sharif University of Technology
    2014
    Abstract
    Core/shell structure of ZnO nanowires coated with a monolayer of TiO 2 is investigated using Density Functional Theory (DFT). The electronic states of the semiconductor is calculated and compared before and after coating of the TiO2 monolayer on a ZnO [101 0] surface. The effect of TiO2 coating induce surface states changes and shifts the conduction and valence band edges to higher energies. Our results, in qualitative agreement with the experimental work of Matt Law et al. (J. Phys. Chem. B, 110, 22652), show an increase in open circuit voltage and a decrease in short circuit current in ZnO/TiO2 core shell dye sensitized solar cells. Regarding the semiconductor density of states (DOS), TiO2... 

    Analyzing factors effective on the development of relationship commitment

    , Article Proceedings of the 2012 International Conference on Artificial Intelligence, ICAI 2012, 16 July 2012 through 19 July 2012 ; Volume 1 , July , 2012 , Pages 398-404 ; 1601322186 (ISBN) ; 9781601322180 (ISBN) Dehdashti, Y ; Lotfi, N ; Karami, N ; Sharif University of Technology
    2012
    Abstract
    Due to the important role of commitment and trust in the relationship marketing, the factors which can directly result in a committed relationship along with the factors which can influence the commitment through influencing trust, according to the model of commitment and trust by (Morgan & Hunt, 1994) have been introduced and their level of importance has been investigated here. The article uses fuzzy cognitive maps (FCMs) in the proposed model to find the most important paths leading to relationship commitment. The FCM analyzes the responses of a group of 30 people including general practitioners in dentistry, managers of dental departments in some of the public clinics and hospitals who... 

    Morphological dependence of light backscattering from metallic back reflector films: Application in dye-sensitized solar cells

    , Article Physica Status Solidi (A) Applications and Materials Science ; Volume 212, Issue 4 , January , 2015 , Pages 785-790 ; 18626300 (ISSN) Sharifi, N ; Ghazyani, N ; Taghavinia, N ; Sharif University of Technology
    Wiley-VCH Verlag  2015
    Abstract
    Conventionally, a film of TiO2 particles of 300 nm size is employed in Dye-sensitized solar cells (DSCs) as the back reflector film to enhance the light harvesting. Perfect reflectance of silver in visible and near infrared motivates to investigate its potential as the material for the light back reflector film in DSCs. In this study, light back reflector films consisting of 300 nm-sized silver particles, as well as vacuum evaporated silver flat film, were fabricated and compared to 300 nm-sized rutile-type TiO2 particulate reflector film to study their optical aspects. Conventional TiO2 rutile-type particulate film demonstrates slightly lower performance... 

    Monolithic dye sensitized solar cell with metal foil counter electrode

    , Article Organic Electronics ; Volume 57 , June , 2018 , Pages 194-200 ; 15661199 (ISSN) Behrouznejad, F ; Taghavinia, N ; Ghazyani, N ; Sharif University of Technology
    Elsevier B.V  2018
    Abstract
    Monolithic dye-sensitized solar cells are conventionally fabricated using carbon composite layer as the counter electrode. In the current research, the brittle carbon composite layer is replaced with a metal foil, aiming to decrease the device series resistance and using less catalyst material in counter electrode. This metallic structure has also an advantage of mechanical strength and decreases the fabrication complexity. The counter electrode is prepared by electrodepositing Cr film followed by electrodepositing Pt nanoparticles on a metal foil. As the porous spacer layer, different composite layers of SiO2, TiO2, and Al2O3 are investigated and the best results are obtained for TiO2... 

    A compact versatile microbial fuel cell from paper

    , Article ASME 2013 11th Int. Conf. on Fuel Cell Science, Eng. and Technology Collocated with the ASME 2013 Heat Transfer Summer Conf. and the ASME 2013 7th Int. Conf. on Energy Sustainability, FUELCELL 2013 ; 2013 ; 9780791855522 (ISBN) Wagner, L. T ; Hashemi, N ; Hashemi, N ; Sharif University of Technology
    2013
    Abstract
    Microbial fuel cells (MFCs) have been a potential green energy source for a long time but one of the problems is that either the technology must be used on a large scale or special equipment have been necessary to keep the fuel cells running such as syringe pumps. Paper-based microbial fuel cells do not need to have a syringe pump to run and can run entirely by themselves when placed in contact with the fluids that are necessary for it to run. Paper-based microbial fuel cells are also more compact than traditional MFCs since the device doesn't need any external equipment to run. The goal of this paper is to develop a microbial fuel cell that does not require a syringe pump to function. This... 

    Decentralized model predictive voltage control of islanded DC microgrids

    , Article 11th Power Electronics, Drive Systems, and Technologies Conference, PEDSTC 2020, 4 February 2020 through 6 February 2020 ; 2020 Abbasi, M ; Mahdian Dehkordi, N ; Sadati, N ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2020
    Abstract
    This paper proposes a novel decentralized control approach for islanded direct-current (DC) microgrids (MGs) based on model predictive control (MPC) to regulate the distributed generation unit (DGU) output voltages, i.e. the voltages of the point of common coupling (PCC). A local controller is designed for each DGU, in the presence of uncertainties, disturbances, and unmodeled dynamics. First, a discrete-time state-space model of an MG is derived. Afterward, an MPC algorithm is designed to perform the PCC voltage control. The proposed MPC scheme ensures that the PCC voltages remain within an acceptable range. Several simulation studies have been conducted to illustrate the effectiveness of... 

    Intelligent optimal feed-back torque control of a 6DOF surgical rotary robot

    , Article 11th Power Electronics, Drive Systems, and Technologies Conference, PEDSTC 2020, 4 February 2020 through 6 February 2020 ; 2020 Tajdari, F ; Ebrahimi Toulkani, N ; Zhilakzadeh, N ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2020
    Abstract
    Sophisticated surgeons are widely indicating the use of surgical robots in order to reject human error, increase precision, and speed. Among well-known robotic mechanisms, parallel robots are broadly more investigated regarding their special characters as higher acceleration, speed, and accuracy, and less weight. Specific surgical procedures confine, and restrict their workspace, while controlling and validating the robots are complicated regarding to their complex dynamic. To this end, in this paper, a 6-DOF robot, with rotary manipulators, is designed and controlled. Addressing nonlinearity of parallel robots, an innovative methodology is formulated to robustly penalize the error of... 

    Semi-Real evaluation, and adaptive control of a 6DOF surgical robot

    , Article 11th Power Electronics, Drive Systems, and Technologies Conference, PEDSTC 2020, 4 February 2020 through 6 February 2020 ; 2020 Tajdari, F ; Ebrahimi Toulkani, N ; Zhilakzadeh, N ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2020
    Abstract
    Sophisticated surgeons are widely indicating the use of surgical robots in order to reject human error, increase precision, and speed. Among well-known robotic mechanisms, parallel robots are broadly more investigated regarding their special characters as higher acceleration, speed, and accuracy, and less weight. Specific surgical procedures confine and restrict their workspace, while controlling and validating the robots are complicated based on their complex dynamic. To this end, in this paper, a 6-DOF robot, with linear manipulators, is designed and controlled. Addressing the inherent nonlinearity of the robot mechanism, an adaptive PID manipulator is employed and validated with nonlinear... 

    Modeling superconductive fault current limiter using constructive neural networks

    , Article 2007 IEEE International Symposium on Industrial Electronics, ISIE 2007, Caixanova - Vigo, 4 June 2007 through 7 June 2007 ; 2007 , Pages 2859-2863 ; 1424407559 (ISBN); 9781424407552 (ISBN) Makki, B ; Sadati, N ; Hosseini, M. N ; Sharif University of Technology
    2007
    Abstract
    Although so many advances have been proposed in the field of artificial intelligence and superconductivity, there are few reports on their combination. On the other hand, because of the nonlinear and multivariable characteristics of the superconductive elements and capabilities of neural networks in this field, it seems useful to apply the neural networks to model and control the superconductive phenomena or devices. In this paper, a new constructive neural network (CNN) trained by two different optimization algorithms; back-propagation and genetic algorithm, is proposed which models the behavior of the superconductive fault current limiters (SFCLs). Simulation results show that the proposed...