Loading...
Search for:
shahrokhian--saeed
0.008 seconds
Total 51 records
Application of Pd-Au Nanoparticles on Carbon Nanotubes Modified Electrode for Electrochemical Determination of Ceftazidime
, M.Sc. Thesis Sharif University of Technology ; Shahrokhian, Saeed (Supervisor)
Abstract
This present work is an introduction of a new electrochemical sensor toward the determination of biomolecule. A simple electrodeposition method was employed to construct a thin film modifier of palladium–gold nanoparticles (Pd–AuNPs) decorated multi-walled carbon nanotube (MWCNT) on the surface of glassy carbon electrode (GCE). Morphological characterization of the modified electrode was performed by the scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and cyclic voltammetry (CV) techniques. This nanostructured film modified electrode effectively exhibited enhanced properties for the detection of ceftazidime (CFZ). The effects of various experimental variables such...
Study and Preparation of the Modified Nanostructure Carbon Electrode for Capacitive Deionization (CDI) Process
, Ph.D. Dissertation Sharif University of Technology ; Ahadian, Mohammad Mahdi (Supervisor) ; Shahrokhian, Saeed (Supervisor)
Abstract
Nowadays capacitive deionization (CDI) has attracted a lot of attention for water treatment. CDI is an emerging water treatment technology that uses electrophoretic driving forces for desalination of water. During the CDI process, ions are adsorbed onto the surface of electrodes by applying a low voltage electric field (DC<2V). In addition, the regeneration of the electrodes contains desorption of the electrosorbed ions from the surface of the electrodes to the water in the absence of the applied electric field. In the mechanism of CDI, separation and accumulation of ions in the electric field are the main processes and no additional chemicals are required in this technology. Therein,...
Morphology-Dependent Electrocatalytic Activity of Silver Nanostructures and Differentia Pulse Voltammetry Determination of Atorvastatin at Silver Nanowires Modified Electrode
, M.Sc. Thesis Sharif University of Technology ; Shahrokhian, Saeed (Supervisor) ; Hormozi Nezhad, Mohammad Reza (Supervisor)
Abstract
In this work two shapes of silver nanostructures including silver nanowires and silver nanocubeswere synthesized by polyol method. Silver nanostructures were characterized by SEM, XRD and UV-Vis spectroscopy. Afterwards the morphology-dependent electrocatalyticperformance of these nanocrystals on the differential pulse behavior of naltrexone (NAL) was investigated. To this aim the differential pulse voltammetric behavior of NAL on a glassy carbon electrode modified with electrochemical deposited gold nanoparticles conjugated with different shapes of silver nanostructures and nafion was investigated. It was proved that silver nanowires show more effective electrocatalytic activity toward...
Design of a Microfluidic System for Continuous Glucose Measurement, as well as Fabricating and Experimentally Testing the Biosensor
, M.Sc. Thesis Sharif University of Technology ; Saeedi, Mohammad Saeed (Supervisor) ; Kazemzadeh Hannani, Siamak (Supervisor) ; Shahrokhian, Saeed (Co-Supervisor)
Abstract
Diabetic patients, unlike other people whose blood glucose vary in a limited and normal range, encounter hyperglycemia and hypoglycemia, so their glucose level should be measured periodically and kept in the normal range. The aim of this research is to design an implantable integrated microfluidic system in order to regularly measure the glucose level in the human body, using the microdialysis method. The main compartments of this system are a micropump, array of hollow microneedles at the base of them located semipermeable membranes, the channels of dialysis fluid and an electrochemical sensor for measuring the glucose level. The micropump of this system is designed and simulated based on...
Design and Fabrication of Flexible Fiber- Shaped Hybrid Micro- Supercapacitors Based on Carbon Nanostructures and Oxides, Sulfides and Phosphides of Some Transition Metals
, Ph.D. Dissertation Sharif University of Technology ; Shahrokhian, Saeed (Supervisor)
Abstract
Miniaturization of electronic devices with portable, flexible and wearable characteristics created a great demand for high-performance microscale energy storage devices with lightweight and flexible properties. Among the energy storage devices, wire-shaped micro-supercapacitors have recently received tremendous attention due to their small size, lightweght, and high flexibility. In the first part, the porous dendritic Ni-Cu film was prepared on Cu wire substrate (CW) for fabrication of high- performance wire-type micro-supercapacitors (micro-SCs). The porous structure with dendritic morphology provides a high surface area, short ion diffusion pathway and low contact resistance between...
Design and Fabrication of Advanced Electrode Materials Based on Metal-organic Frameworks and Double Layered Hydroxides Using Hollow Copper Hydroxide Nanotubes Scaffold; Application to Nonenzymatic Glucose Sensor
, M.Sc. Thesis Sharif University of Technology ; Shahrokhian, Saeed (Supervisor)
Abstract
One of the remarkable subject in advanced electrochemistry is, design and architecting new advanced materials with new electrochemical capabilities. One of the notable capabilities is electrocatalysis. Extensive researches are carrying out into the design and preparation of electrocatalyst materials to take advantage of these materials in fabrication of electrochemical sensors and storage/conversion devices. In this field nonoporous materials attracted a lot of attentions due to their unique features. In order to make use of the nanoporous materials as the electrocatalysts, these materials must be fabricated into continuous supported thin films on the electrode surface, which is the...
Design and Implementation of Near Field Excitation System for Spectroscopy of Biological Species
, Ph.D. Dissertation Sharif University of Technology ; Rashidian, Bizhan (Supervisor) ; Vossoughi, Manouchehr (Supervisor) ; Shahrokhian, Saeed (Co-Advisor)
Abstract
The main goal of this project is analysis, design and implementation of scanning near field optical system for detection of biological species. The activities fall in two main category. Theoretical and experimental. In theoretical part, after studying different models describing near field interaction, we have developed software for computationally analysis of nonlinear interaction of light with nanostructures, considering third order nonlinear susceptibility and dispersion behavior of permittivity for metallic nanostructures. The software implements three dimensional finite difference time domain (FDTD) method for analysis of interaction of electromagnetic wave with matter. In developed...
Design and Fabrication Nanocomposite Modified Electrode Materials Based on Transition Metal Phosphide Using Copper Hydroxide Nanotubes as a Catalytic Substrate for Glucose Sensing in Non-Enzymatic Sensors
, M.Sc. Thesis Sharif University of Technology ; Shahrokhian, Saeed (Supervisor)
Abstract
In this study, transition metal phosphide, with a high accessible surface and abundant electroactive centers, was used as an electrocatalyst to fabrication an electrochemical sensor of Gloucose. The direct growth of thin film of nanocomposite can be considered as an efficient method to modify the electrode surface, and the application of these modified electrodes as electrochemical sensors. nanocomposite of transition metal phosphide (CuCoP) were directly grown on Cu(OH)2 nanotubes (as-prepared on GCE) in order to design hierarchical core-shell nanostructure with using efficient, inexpensive and fast method. Here, Cu(OH)2 nanotubes not only served as substrate, but also steer the CuCoP to...
Design and Fabrication of Supercapacitors Based on Modified Carbon Nanospheres Using Transition Metal Oxide/Hydroxide
, M.Sc. Thesis Sharif University of Technology ; Shahrokhian, Saeed (Supervisor)
Abstract
Herein a simple tow step method is developed to design hierarchical binder free structure of binary nickel cobalt carbonate hydroxide decorated hydrothermal carbon sphere. First carbon sphere were synthesized on nickel foam via hydrothermal process using glucose solution followed by carbonization process. Ni Co carbonate hydroxide core shell array were directly grown on binder free carbon spheres using hydrothermal method. The synthesized electrode afforded high specific capacitance (497/83 mAhg-1 at a current density of 1/4 A g-1) and good cyclic stability (85% after 1500 charge / discharge cycles). EIS measurement showed negligible internal resistance (0.638 Ω) which is attributed to the...
Design and Development of Electrochemical DNA Nanobiosensors for Identification and Determination of Important Biomarkers
, Ph.D. Dissertation Sharif University of Technology ; Shahrokhian, Saeed (Supervisor) ; Kalhor, Hamid Reza (Co-Supervisor)
Abstract
The main purpose of this Ph.D. Thesis is to develop DNA-based biosensors using Label-free approaches applying simple, inexpensive and fast electrochemical techniques to measure the biological markers of cancer.In the first part, a simple protocol for detection of specific-sequence DNA is introduced. In this method carbon nanotube is used as a hybridization indicator. This label-free system provides the advantage of eliminating additional labeling procedure. As the signal enhances in the presence of MWCNT and decreases in the presence of target, the fabricated sensor is known as a signal-off device. The oxidation signal of Fe(CN)63-/4- is followed as an analytical signal to detect target...
Design of Plasmonic Systems for Nanobiophotonic Applications
, Ph.D. Dissertation Sharif University of Technology ; Rashidian, Bizhan (Supervisor) ; Vosoughi, Manouchehr (Supervisor) ; Shahrokhian, Saeed (Co-Advisor)
Abstract
In this thesis periodic plasmonic nanostructures are studied for detection of biological specious. The behavior of metal nanostructure arrays under normal incidence has been widely reported. However, simulation of periodic dispersive structures under oblique incidence requires newer formulations. Formulations, and algorithms based on modified split-field finite-difference time-domain (SF-FDTD) method are introduced, permitting analysis of metallic nanostructures arrays under oblique incidence. These novel algorithms are practically implemented on a parallel processing system based on graphics processing unit (GPU). Test and verification of these formulations are done by analyzing referenced...
Design, Construction and Application of Nanostructured Electrochemical Biosensor Based on Aptamers for Diagnosis Some of the Pathogenic Bacteria
, Ph.D. Dissertation Sharif University of Technology ; Shahrokhian, Saeed (Supervisor)
Abstract
Since that pathogenic bacteria have a predominant role in different aspects of human life such as clinical analysis and spread of contagious disease, food quality control and monitoring of environmental microbial infections, the aim of these studies is design and construction of electrochemical and electro-optical biosensors based on nanomaterials employing specific aptamer and antibody for detection of different bacteria in various real samples. An impedimetric biosensor based on nanoporous gold (NPG) was presented in the first part of the thesis for detection of Salmonella typhimurium as one of the main food- borne pathogenic bacterium. Three-dimensional structure of NPG was synthesized...
Design, Construction and Investigation of the Behavior of Electrocatalysts Based on Some Transition Multi Metals Nanostructures toward Electrochemical Water Splitting
, Ph.D. Dissertation Sharif University of Technology ; Shahrokhian, Saeed (Supervisor)
Abstract
Energy and the environment issues are among the most important concerns of the present age. Global demand for energy is growing rapidly and energy demand is projected to double within the next 15 years. However, today most of the energy consumption comes from fossil fuels, which have limited and unstable reserves and are among the sources of environmental pollution. Hence, the production and conversion of clean energy from renewable sources is considered as an intelligent solution to significantly reduce dependence on fossil fuels and protect the environment. Fuel cells, metal-air batteries, and water electrolysis are among the simplest, most efficient, and most reliable technologies among...
Synthesis and Stability Evaluation of Single Enzyme Nanoparticles for Enzymatic Based Processes
, Ph.D. Dissertation Sharif University of Technology ; Vossoughi, Manoochehr (Supervisor) ; Shahrokhian, Saeed (Co-Advisor) ; Alemzadeh, Iran (Co-Advisor)
Abstract
Enzymes, the nanometric biocatalysts that play a key role in biochemical reactions of living cells and bio-organisms, offer various applications including biosensing, bioremediation and chemical synthesis. A simple bio-conjugation procedure to surround a single horseradish peroxidase (HRP) enzyme molecule with dendritic polyester macromolecules (Polyester-32-hydroxyl-1-carboxyl bis-MPA Dendron, Generation 5) was proposed in this project. The characterization of resultant nanoparticles entitled HRP dendrozyme, was performed by TEM, DLS, GPC and FTIR spectroscopy. The results showed that HRP nanoparticles were spherical in shape and have an average size of 14 nm in diameter. Furthermore,...
Synthesis of Hybrid Graphene Nanostructures and Their Application in Design and Fabrication of Electrochemical Sensors for Pharmaceutical and Biological Applications
, Ph.D. Dissertation Sharif University of Technology ; Shahrokhian, Saeed (Supervisor) ; Iraji Zad, Azam (Supervisor) ; Mohajerzadeh, Shamsoddin ($item.subfieldsMap.e)
Abstract
Recent years have witnessed an increasing interest in graphene and graphene-based materials due to their extraordinary electrical properties, large specific surface area, fascinating mechanical properties, good chemical stability and remarkable electrochemical activity. The combination of these properties make graphene an attractive candidate for a wide range of applications including energy conversion and storage devices (batteries and supercapacitors), electronic devices (transistors and memory devices) and solar cells. On the other hand, graphene has a potential application in constructing different kind of sensors such as biosensors and electrochemical sensors due to its planar...
Fabrication and Investigation of Supercapacitors Based on Graphene Nanocomposites
, Ph.D. Dissertation Sharif University of Technology ; Iraji Zad, Azam (Supervisor) ; Shahrokhian, Saeed (Supervisor)
Abstract
Development of renewable energy production from sun and wind and the development of hybrid electric vehicles seem to be integral components in modern societies in order to overcome the environmental pollution and reduce the use of fossil fuel sources. In such devices energy storage plays an important role and supercapacitor is one the important energy storage devices. Structure of supercapacitor electrodes has considerable effect on supercapacitor performance. Graphene as a 2D carbon structure can improve electrochemical properties of electrodes. Here three different hybrid structure of graphene have been realized. The high capacitance and cyclic stability of graphene nanosheets decorated...
Constructing and Investigation of the Electrochemical Behavior of Nanocomposite of Conducting Polymers on Copper Hydroxide Nanotubes; Application to Determination of Glucose
, M.Sc. Thesis Sharif University of Technology ; Shahrokhian, Saeed (Supervisor)
Abstract
A novel amperometric non-enzymatic glucose (NEG) sensor is designed by a facile preparation method. It is made by electrodeposition of Cu clusters and converting them to Cu(OH)2 nanotubes (Cu(OH)2NTs) arrays along with thin-film electro-polymerized of spindle-shaped polypyrrole (PPy@Cu(OH)2NTs), which have been doped by using sodium Benzene-1,3- disulfonate as an anion dopant. The electrochemical performance of the modified electrode toward glucose detection is investigated by various electrochemical methods. Under the optimized conditions, a significant electrochemical response improvement is observed toward the electro-oxidation of glucose on the surface of PPy@Cu(OH)2NTs electrode...
Fabrication of Hybrid Supercapacitors Based on Graphene-Conducting Polymers and Some Metallic Oxides and Sulfides and Investigation of Their Electrochemical Behavior
, Ph.D. Dissertation Sharif University of Technology ; Shahrokhian, Saeed (Supervisor) ; IrajiZad, Azam (Co-Supervisor)
Abstract
In this research, metal oxides and hydroxides with carbon materials and conductive polymers (CPs), as well as transition metal oxysulfide nanostructures (TMOS), hybrid of Tin oxide and sulfie and polyphasphate-reduced graphene oxide (PPO-RGO) have been used as an active electrode materials for supercapacitors. In the first section of thesis, Tiron and graphene oxide (GO) were used as an anionic dopants to increase the capacity and stability of polypyrrole (PPy). In order to increase the capacity of Tiron/PPy/GO nanocomposite, vanadium oxide (V2O5) was used. The Tiron/PPy/GO/V2O5 nanocomposite was deposited on a stainless steel (SS) as a substrate via one-step electrochemical deposition...
Growth of Polymer/TiO2 Nanostructures by Layer-by-Layer Self Assembly Method as Electrodes of Photoelectrochemical Cells
, Ph.D. Dissertation Sharif University of Technology ; Taghavinia, Nima (Supervisor) ; Shahrokhian, Saeed (Co-Advisor)
Abstract
Dye sensitized solar cells (DSCs) are among the 3rd generation solar cells which their mechanism of light absorption is similar to chlorophyll in green leafs and is based on photo-excitation of dyes. The electron-hole pairs of photo-excited dye separate at the interface of mesoporous semiconductor-dye-electrolyte. One of the approaches to increase the light path length and therefore the light harvesting efficiency in DSC is the addition of light scatterers inside the mesoporous semiconductor (photoanode).In this research, nanoparticulated hollow TiO2 fibers are introduced as novel light scatterers in DSCs with simultaneous light scattering, light trapping and high surface area. Light...
Electrochemical Sensors Based on Electrodes Modified with Composites of Carbon Nanostructures and Polypyrrole; Application to Electrochemical Investigations and Determination of Nifedipine and Tizanidine
, M.Sc. Thesis Sharif University of Technology ; Shahrokhian, Saeed (Supervisor)
Abstract
In the first part, the electropolymerization of pyrrole was performed in the presence of Titan Yellow (TY) as a dopant anion on the surface of the electrode precoated with CNTs. The modified electrode was used to study the voltammetric response of tizanidine (TIZ). A remarkable increase was observed in the anodic peak current of TIZ on the surface of the modified electrode relative to the bare GCE. The surface morphology PPY/CNT/GCE was thoroughly characterized by scanning electron microscopy (SEM) and cyclic voltammetry (CV) techniques. Under the optimized analysis conditions, the modified electrode showed two linear dynamic ranges of 0.01 - 1 μM and 1-10 μM with a detection limit of 3 nM...