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    Synthesis and Optimization of Metal Oxide Catalysts Supported on Nano-structured Alumina for Oxidation of Toluene from Contaminated Air

    , M.Sc. Thesis Sharif University of Technology Jafari, Mina (Author) ; Khorashe, Farhad (Supervisor) ; Kazemeni, Mohammad (Supervisor)
    Exhaust gases from poultry rendering facilities contain volatile organic compounds (VOCs) that are a nuisance, odorous, and smog and particulate matter precursors. Other available treatment options, such as thermal and catalytic incineration require temperature intensive inputs and form additional greenhouse gases. Hence, an inexpensive alternative technology is needed to eliminate these air pollutants. This research investigated the catalytic oxidation of toluene vapors using novel dispersed nano catalysts derived from new preparation method. The combined impregnation (IMP) and deposition-precipitation (DP) was used to prepare supported transition metal oxide catalyst over commercial and... 

    Manganese and cobalt-terephthalate metal-organic frameworks as a precursor for synthesis of Mn2O3, Mn3O4 and Co3O4 nanoparticles: Active catalysts for olefin heterogeneous oxidation

    , Article Inorganic Chemistry Communications ; Volume 61 , 2015 , Pages 73-76 ; 13877003 (ISSN) Ashouri, F ; Zare, M ; Bagherzade, M ; Sharif University of Technology
    Elsevier  2015
    The thermal decomposition of manganese and cobalt-terephthalate Metal-Organic Framework precursors was utilized as a synthetic route for fabrication of Co3O4, Mn3O4 and Mn2O3 nanoparticles. The prepared metal oxide nanoparticles of Co3O4, Mn3O4 and Mn2O3 possess average size diameter of 40, 60 and 80 nm respectively. The findings demonstrate that spinel structure nanoparticles of Co3O4 and Mn3O4 exhibit efficient catalytic activity toward heterogeneous olefin epoxidation in the presence of tert-butyl hydroperoxide. In... 

    N-doped ZnO-CuO nanocomposite prepared by one-step ultrasonic spray pyrolysis and its photocatalytic activity

    , Article Chemical Physics Letters ; Volume 705 , 2018 , Pages 19-22 ; 00092614 (ISSN) Rahemi Ardekani, S ; Sabour Rouhaghdam, A ; Nazari, M ; Sharif University of Technology
    Elsevier B.V  2018
    Nanocomposite thin film of N-doped ZnO-CuO was deposited on glass substrate using ultrasonic spray pyrolysis method. Zinc acetate, copper acetate and ammonium acetate with different molar ratios were dissolved in water and used as precursors. A crumpled-shape morphology consisting of nanometer-sized particles was observed with FESEM. The elemental composition was evaluated with EDX analysis and the presence of nitrogen, oxygen, copper and zinc was confirmed. XRD analysis revealed the presence of ZnO and CuO crystalline phases with crystallite size of about 18 nm. The prepared nanocomposites exhibited high photocatalytic activity in degradation of methyl orange under UV light irradiation. ©... 

    Reproducible electrochemical analysis of nanostructured Cu2O using a non-aqueous 3-methoxypropionitrile-based electrolyte

    , Article Electrochemistry Communications ; Volume 86 , 2018 , Pages 1-5 ; 13882481 (ISSN) Shooshtari, L ; Iraji zad, A ; Mohammadpour, R ; Sharif University of Technology
    Elsevier Inc  2018
    Cu2O is an attractive material in terms of semiconducting properties and is considered a leading candidate in all-oxide photovoltaics. Electrochemical analysis of Cu2O, including Mott-Schottky (MS) and impedance spectroscopy (IS), provides a wealth of data on charge carriers, Fermi level and interface properties. MS and IS are usually measured in aqueous solutions. However, Cu2O is easily reduced or oxidized to Cu or CuO in aqueous solutions, the layer peels off after the analysis and there is a small voltage window for the tests. In some cases, an anti-corrosive n-type barrier layer is employed on top of the bare Cu2O electrode to make the measurement possible, which could result in... 

    Theoretical analysis of the performance of a model supercapacitor consisting of metal oxide nano-particles

    , Article Journal of Solid State Electrochemistry ; Volume 11, Issue 8 , 2007 , Pages 1085-1092 ; 14328488 (ISSN) Farsi, H ; Gobal, F ; Sharif University of Technology
    The factors influencing the electrochemical behaviour of a supercapacitor have been partly examined in this work. The effects of so-called intrinsic parameters, i.e. exchange current density, unit cell length and double layer (DL) capacitance; as well as the so-called application parameters, i.e. cell current, on the cell potential discharge time have been considered. The contributions of each type of capacitors, DL capacitor and faradaic supercapacitor under various states of operation and material have been analyzed, and the competing (compensating) effects of the two types of capacitors as regards to the discharge and power characteristics manifested by current-potential and energy-power... 

    Preparation and Characterization of Ternary Mixed Oxide Containing IrO2,RuO2,TiO2 on Platinum Coated Titanium Anode

    , M.Sc. Thesis Sharif University of Technology Ali Asghari, Sepideh (Author) ; Ghorbani, Mohammad (Supervisor) ; Davami, Parviz (Supervisor)
    Ruthenium based-oxide coatings on Titanium anodes are widely used as DSA (Dimensionally Stable Anode) for chlorine and chlorate production. Coatings consisting of composition of highly conductive oxide of noble metals (Ru, Ir and Pt) make them as long lasting anodes in chlor-alkali technology.In this work, a newly anode by a ternary coating of IrO2, RuO2, and TiO2 on the Pt-coated Ti was developed through thermal decomposition of iridium and titanium and ruthenium inorganic salts dissolved in n-pentane. The effect of deposition parameters such as current density, time, different condition of baking, heating, mole ratio and pulling up the samples was investigated to find out reasonable... 

    Synthesis and characterization of NiCo2O4 nanorods for preparation of supercapacitor electrodes

    , Article Journal of Solid State Electrochemistry ; Vol. 19, Issue. 1 , 2014 , pp. 269-274 ; ISSN: 1432-8488 Jokar, E ; Zad, A. I ; Shahrokhian, S ; Sharif University of Technology
    Here, a solvothermal method for synthesis of porous Ni–Co binary oxide (NiCo2O4) nanorods followed by thermal decomposition is described. The prepared nanorods were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer Emmett Teller (BET) methods. These porous NiCo2O4 nanostructures were promising candidates in the development of high capacity supercapacitors and having excellent cycling performance due to high specific surface area. In addition, the influence of annealing rate on the structure and electrochemical behavior of the synthesized nanorods was investigated. The results showed that the annealing rate had a direct effect on the crystalline... 

    The Kinetic and Mechanism Evaluation of Photocatalytic Degradation of Environmental Pollutants Using Modified Nanocomposites

    , Ph.D. Dissertation Sharif University of Technology Gholizadeh Khasevani, Sepideh (Author) ; Gholami, Mohammad Reza (Supervisor)
    Different nanocomposites were prepared based on the carbon nitride, structures and metal organic framework. The photocatalytic activities of a group of metal-organic metal frameworks were evaluted. Next step, the combination of binary and ternary composites based on carbon nitride/metal-organic frameworks structures with other semiconductors such as oxyacid, bismuth oxy halide and ferrite spinel was used. In addition, synthesis of varius type of metal oxides structures with metal organic framework precursors has also been another perpuse of this thesis.The catalytic and photocatalytic activities of designed nanocomposites were performed for a redox process (4-nitrophenol (4-Nip) to... 

    Preparation and Characterization of Nanostructural Ternary Mixed Oxide Containing Ti/Ru/Ir on Titanium by Sol-gel Process for MMO Electrode

    , Ph.D. Dissertation Sharif University of Technology Goudarzi, Mona (Author) ; Ghorbani, Mohammad (Supervisor)
    In this study, ternary metal oxide coating consisting of Ti, Ru, Ir were prepared by sol-gel method. In order to achieve optimal conditions, the effect of number of layers, temperature and velocity of the heat treatment, the amount of ruthenium and iridium, polymeric additive on the coating and also, comparisons of binary and ternary oxide coatings were studied. The corrosion behavior was examined by anodic polarization and cyclic voltammetry tests and accelerated stability test (AST), the morphology of coatings was studied by field emission scanning electron microscopy (FESEM), phase and elemental analysis was performed using X-ray diffraction (XRD) and energy dispersive spectroscopy... 

    Desion an Appropriate Supported transition Metals Oxide Over Alumina Catalyst for Deep Oxidation of Cyclohexane in Air

    , M.Sc. Thesis Sharif University of Technology Jafari, Masoumeh (Author) ; Khorashe, Farhad (Supervisor) ; Kazemini, Mohammad (Supervisor)
    Volatile Organic Compounds (VOCs) have become an important source of air pollution due to their extended use as solvents in many industrial processes. Aliphatic and aromatic VOC removal from contaminated air can be achieved by a variety of methods including catalytic oxidation, adsorption, and biological treatment. Catalytic oxidation is often the preferred process due to its low cost and high efficiency. Supported transition metal catalysts are effective and inexpensive catalysts for VOC removal from contaminated air. The objective of this project was to prepare low cost transition metal catalysts (Fe, Ni, Co, and Cu) supported on alumina for catalytic oxidation of cyclohexane (as a... 

    Synthesis and Electrochemical Evaluation of Graphene-Ni/Cu/Zn Nanocomposite Coating Modified by Pt/Ru Nanoparticles

    , Ph.D. Dissertation Sharif University of Technology Yaghoubinezhad, Yadollah (Author) ; Afshar, Abdollah (Supervisor)
    In this research,Graphene Oxide nanoplatelets (GO) were synthesized by chemically modified Hummer's method.After the GO nanosheets electrochemically reduced to graphene, nanoparticles imposed to this thin film.This optimized nanostructure coating was utilized for investigating the Hydrogen Evolution Reaction (HER) over the copper substrate. In order to optimize the kinetic of electrodeposition and reduction, diverse electrochemical approaches such as cyclic voltammetry, chronoamperometic and potentiometric as well as pulse electrodeposition methods were employed. Electrochemical procedures were aligned by Design of Experiment (DOE) ... 

    Design and Fabrication of Passive CMOS Phase Shifter

    , M.Sc. Thesis Sharif University of Technology Azizi Ghannad, Mehrdad (Author) ; Medi, Ali (Supervisor) ; Atarodi, Mojtaba (Co-Advisor)
    This research examines the issues of design and fabrication of Phase Shifter circuits on Silicon substrates. The Phase Shifter circuits are designed to have wide operation band width. They also should have very low sensitivity to process and temperature variation. A six bit phase shifter is designed at this research. We use a new topology for implementing the small phase shift steps and some circuits have been designed which their phase shifts can be adjusted after fabrication. All circuits are implemented with the 0.18µm CMOS technology. The research also explains all the necessary steps for measurement of fabricated circuits. The result of measurements shows good agreement with the... 

    Over 10-b On-Chip Impedance Measurement System for High Frequency Range

    , M.Sc. Thesis Sharif University of Technology Mirjalili, Ramin (Author) ; Atarodi, Mojtaba (Supervisor) ; Mehrani, Khashayar (Supervisor)
    Diabetes is one of the most catastrophic diseases in the world. There will be an end to patients’ problems if scientists can invent the artificial pancreas, but there is no implantable sensing core available. All of the sensors used for measuring blood glucose level were based on an electrochemical sensor which will generate a glucose level dependent electric current. The chemical structure of that sensor will deny its usability for in vivo applications. By exploring several biological and electrical literatures we introduced a fully electrical method for sensing the blood glucose level by impedance measurement. In this thesis we introduced a new method for sensing the blood glucose... 

    Frequency Domain HF on-chip Impedance Spectroscope with Over 10 bit Resolution

    , M.Sc. Thesis Sharif University of Technology Bakhshiani, Mehran (Author) ; Atarodi, Mojtaba (Supervisor) ; Mehrani, Khashayar (Supervisor)
    Impedance spectroscopy is known as one of the important integrated sensing methods in micro scale Biosensors and electrochemical sensors. Recently, Impedance spectroscopy has been noticed in many micro scale applications. These micro scale applications is being developed specially in bioelectronics and biomedical. The goal of this thesis is designing an on-chip impedance spectroscope system for high frequency with 10 bits resolution via fully electrical blood glucose concentration measurement. This system extracts the blood glucose concentration data through measuring the permittivity coefficient of blood at 1 GHz frequency. In this thesis, new method for high frequency high resolution... 

    Analysis of Digital DSP Blocks Using GDI Technology

    , M.Sc. Thesis Sharif University of Technology Faed, Mahdi (Author) ; Mortazavi, Mohammad (Supervisor)
    In line with developments in the technology of integrated circuits, transistors are implemented in silicon. Although the price is reduced; design is more complicated, which causes the efficiency and power consumption to face some difficulties in such design. The reason why modern GDI-based circuit is the focus of attention is that in designing a digital circuit, less power is required while more efficiency is obtained. Lowering the complexity of the logic circuit can bring about reduction of power consumption and propagation delay and decrease the circuit space. GDI-based integrated circuits resemble MOSFET transistors but have fewer transistors and higher performance capability. This study... 

    Design and Implementation of Ku-Band Variable Gain Amplifier in 0.18μm CMOS Technology

    , M.Sc. Thesis Sharif University of Technology Barzgari, Mohammad (Author) ; Medi, Ali (Supervisor)
    In this thesis, a Ku-band (16.3-17.3) Variable Gain Amplifier (VGA) for realizing a phase array T/R module is designed, implemented and measured in CMOS 0.18μm technology. In order to achieve a maximum gain of 15dB and NF of 4.3dB and with the idea of improving the 1-dB compression point, two gain-stages and a novel inter-stage is proposed according to pre-distortion method. Applying this linearizing technique, makes it possible to get output P-1dB higher than 18dBm. Current steering technique is used for gain control mechanism. Gain tunabality range of 31.5dB is needed and this forces 6-bit operation with 0.5dB gain-step for the VGA. Because of loading effect of higher bits on the lower... 

    Design and Implementation of X Band CMOS Vector Modulator

    , M.Sc. Thesis Sharif University of Technology Arjmandpour, Sina (Author) ; Medi, Ali (Supervisor) ; Kavehvash, Zahra (Supervisor)
    In this thesis, an X band vector modulator chip in CMOS .18 um technology is designed, implemented and measured. The receiver with two RF signal path includes differential amplifier, hybrid, attenuaters, variable gain amplifiers (VGA) and power combiner blocks respectively. Capability of gain and phase control is provided by 14 digital bit. 6 bits are used to control gain of each RF path, so that changing the phase and gain of the output signal in a trigonometric quarter shall be possible. The trigonometric quarter is selected by two single pole double throw switch. Cascode structure is utilized in amplifiers stages for its stability and isolation feature. Furthermore, in order to to enhance... 

    Design and Implementation of X-Ku Band Variable Gain Amplifier in CMOS Technology

    , M.Sc. Thesis Sharif University of Technology Shojaei, Mehdy (Author) ; Medi, Ali (Supervisor)
    In this thesis, a new wide band variable gain distributed amplifier (VGDA) is presented. A novel approach to implement uniform gain control in the wide band frequency range of 8 – 18 GHz is demonstrated. A different technique has been employed to provide necessary DC bias current, avoiding large DC-Feed inductors. A five-section wideband VGDA has been designed and fabricated in 0.18 μm CMOS technology. The VGDA have a flat gain of 11 dB, noise figure better than 5 dB, P1dB of 14 dBm at the output, input and output matching better than -12 dB and -14 dB, respectively, for maximum gain state over the 10 GHz UWB band. The gain control range is between 3 – 11 dB with gain steps of 0.5 dB and rms... 

    Electronic Structure Calculation of (Sr,Ca)2Ru04 By GW Approximation

    , M.Sc. Thesis Sharif University of Technology Hooshmand Quarebagh, Zahra (Author) ; Akhavan, Mohammad (Supervisor)
    In this thesis, we have studied systems called Ruthenates, which are common in possessing Ru element in their chemical compounds. Ruthenates are a group of transition metal oxides which have attracted so attention, especially in last years duo to their rich phase diagram which shows different orbital, charge and spin orderings.They cover a vast range of materials properties, from a Superconductor to Mott Hubbard insulator, from a paramagnetic metal to an antiferromanetic insulator. In these systems, substituting a covalent atom with structure base, leads to a vast variety changing, not only in electronic properties but also in magnetic and structural ones: Although Sr"RuO£ is a... 

    Design and Implementation of Fully Integrated Frequency Synthesizer for Biomedical Applications

    , M.Sc. Thesis Sharif University of Technology Aghlmand, Fatemeh (Author) ; Atarodi, Mojtaba (Supervisor)
    Fully integrated frequency synthesizer is one of the important system-on-chips building blocks. Among this circuit’s remarkable applications, Bioelectronics field is very common. In these applications, advanced microelectronic circuits are used in order to diagnosis and treatment of diseases. The aim of this thesis is design and implementation a wideband frequency synthesizer in a 0.18um CMOS technology. The main usage of this circuit is in a fully integrated implantable biomedical sensory chip. This circuit generates two necessary local signals in sensory chip to stimulus cells and process the information.
    Frequency synthesizer is based on phased locked loop (PLL) circuit and produce...