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Structural Study of Vitamin B1, B2 and B6 by NMR Spectroscopy and ab-initio Methods

, M.Sc. Thesis Sharif University of Technology Aghaee, Zahra (Author) ; Tafazzoli, Mohsen (Supervisor)

Abstract

The structure and energy of vitamin B1 (Thiamine), vitamin B2 (Riboflavin) and vitamin B6 (Pyridoxine) have been studied employing quantum mechanical calculation, DFT methods at B3LYP level using 6-311+G* basis set. Values of the coupling constants involving carbon-hydrogen and hydrogen-hydrogen on the torsion angle α and β were theoretically calculated. All Karplus equations which represent the correlation between coupling constants 1JCH, 2JHH, 2JCH, 3JHH, 3JCH and proper dihedral angle have been yielded. The effect of three solvents, water, ethanol and carbon¬ tetrachloride with different polarity on coupling constants, energy and structural parameters were calculated employing PCM model....

Multiverse and the Fine-Tuning of the Constants of Nature

, M.Sc. Thesis Sharif University of Technology Aghaee, Faez (Author) ; Golshani, Mehdi (Supervisor)

Abstract

In recent decades, the idea of multiverse has been raised in several areas of physics for different reasons. One of the interpretations of quantum mechanics, the inflation theory in cosmology and string theory in fundamental physics have led to the multiverse idea. On the other hand, after the problem of fine-tuning of the constants of nature became a hot topic in recent decades, physicists have tried to find a way to explain this puzzle. One of the most important approaches that have been suggested by some physicists, as a scientific explanation for this problem, is the idea of multiverse and they are even willing to set aside the principle of observability to confirm physical...

PLC Implementation of Fractional Order Controllers

, M.Sc. Thesis Sharif University of Technology Aghaee, Mehdi (Author) ; Tavazoei, Mohammad Saleh (Supervisor)

Abstract

In this thesis, various fractional order controllers (FOCs), e.g., FO-PID, FO-TID, CRONE and FO-Lead/Lag, are implemented using PLC. For this purpose first, several methods are used to approximate the differentiator and integral operators. Based on these methods, the equivalent rational transfer functions of the fractional order controllers are obtained. Then, using STEP7 software, the FOCs are implemented in Siemens PLC. Moreover, to facilitate the use of the implemented FOCs in the industry and to take full advantage of the controllers, WinCC software as an interface between human and machine (HMI) is used. The WinCC software enables the operator to access the PLC through a computer (PC)...

Real Time Trend Forecasting of Noisy Signal Using Deep Recurrent LSTM Network

, M.Sc. Thesis Sharif University of Technology Aghaee, Arman (Author) ; Vosoughi Vahdat, Bijan (Supervisor)

Abstract

Artificial neural networks are mathematical models inspired by the nervous system and brain. The types and applications of these networks are very widespread nowadays, and it seems that they can be used to track the signals well and estimate the data of the next. In this research, we try to present a model that can predict the future of the trend of noisy signals that have unpredictable behavior, or in other words, chaotic signals. Such research is also widely used in the medical sciences, including the diagnosis of epileptic seizures or heart attacks. In this research, a study with high volatility financial data has been done as an example on this issue and the proposed model tries to be...

Active distance-based clustering using k-medoids

, Article Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 19 April 2016 through 22 April 2016 ; Volume 9651 , 2016 , Pages 253-264 ; 03029743 (ISSN) ; 9783319317526 (ISBN) Aghaee, A ; Ghadiri, M ; Soleymani Baghshah, M ; Sharif University of Technology

Springer Verlag 2016

Abstract

k-medoids algorithm is a partitional, centroid-based clustering algorithm which uses pairwise distances of data points and tries to directly decompose the dataset with n points into a set of k disjoint clusters. However, k-medoids itself requires all distances between data points that are not so easy to get in many applications. In this paper, we introduce a new method which requires only a small proportion of the whole set of distances and makes an effort to estimate an upperbound for unknown distances using the inquired ones. This algorithm makes use of the triangle inequality to calculate an upper-bound estimation of the unknown distances. Our method is built upon a recursive approach to...

Concept Extraction of Sequential Patterns for Imitative Learning

, M.Sc. Thesis Sharif University of Technology Arjomand Aghaee, Ehsan (Author) ; Bagheri Shouraki, Saeed (Supervisor)

Abstract

The aim of this thesis is the concept extraction of sequential patterns for imitative learning for humanoid robots. In such a way that an existent that has the physical and cognitive similarities, begins to extract concepts and learns by observing the behavior of the other existent. In this project, it is assumed a humanoid robot that can understand the concepts such as hello, goodbye and different concepts and does the corresponding actions from the visual and auditory information. In this thesis, a new model has been presented to eliminate the improper and meaningless elasticity in patterns sequence, such as changes in accent or elasticity in movements. This model is called the fuzzy...

Two-phase flow separation in axial free vortex flow

, Article Journal of Computational Multiphase Flows ; Volume 9, Issue 3 , 2017 , Pages 105-113 ; 1757482X (ISSN) Aghaee, M ; Ganjiazad, R ; Roshandel, R ; Ashjari, M. A ; Sharif University of Technology

2017

Abstract

Multi-phase flows, particularly two-phase flows, are widely used in the industries, hence in order to predict flow regime, pressure drop, heat transfer, and phase change, two-phase flows should be studied more precisely. In the petroleum industry, separation of phases such as water from petroleum is done using rotational flow and vortices; thus, the evolution of the vortex in two-phase flow should be considered. One method of separation requires the flow to enter a long tube in a free vortex. Investigating this requires sufficient knowledge of free vortex flow in a tube. The present study examined the evolution of tube-constrained two-phase free vortex using computational fluid dynamics. The...

Spin effect on band structure of zigzag and armchair graphene nanoribbones with Stone-Wales defect

, Article 2013 21st Iranian Conference on Electrical Engineering ; May , 2013 , Page(s): 1 - 4 ; 9781467356343 (ISBN) Faez, R ; Barami, S ; Sharif University of Technology

2013

Abstract

In this paper the band structure of spin polarized zigzag graphene nanoribbons(ZGNRs) and armchair graphene nanoribons(AGNRs) with Stone-Wales defect are investigated. The results show when the spin effect is considered, the band structures of ZGNRs and AGNRs will be changed and modified. A larger gap will be created and the degenerate bands in ZGNRs will become far from each other. Tight-binding and hubard model were used to simulate the band structures

Design of a very fast logic gate using MBT

, Article Scientia Iranica ; Volume 7, Issue 3-4 , 2000 , Pages 212-218 ; 10263098 (ISSN) Faez, R ; Tabandeh, M ; Sharif University of Technology

Sharif University of Technology 2000

Abstract

Metal Base Transistor (MBT) is a device capable of working in very high frequencies. However, it suffers from a low current gain. By cascading several MBTs, one can obtain an acceptable gain. Using this type of circuit, a new logic gate has been designed in this paper in order to obtain a very fast gate while keeping a reasonable power delay product. In this design, a logic swing of 0.5 volt is chosen and, considering a noise margin of 0.1 V in each side, a total swing of 0.7 V is obtained. In the design, a fan out of three was considered, for which the relevant delay obtained was 15.5 ps and the power delay product for the gate was 310 fJ

Investigation of Impurities and Structural Defects in Graphene

, M.Sc. Thesis Sharif University of Technology Rostami, Melika (Author) ; Faez, Rahim (Supervisor)

Abstract

In this thesis the effects of impurities and different defects on electrical and magnetic properties of monolayer and bilayer graphene is investigated. Calculations are performed using density function theory. Alloying monolayer graphene with boron and nitrogen the energy gaps of 0.7 and 0.6 eV are obtained, respectively. Moreover, we show that BN is a good candidate for opening the band gap in graphene. Alloying monolayer graphene with BN the energy gap of 1.2 eV is obtained. Another way of opening band gap is to somehow break the symmetry between layers of the bilayer graphene. By alloying one layers of bilayer graphene with B, N or B-N, although the symmetry of layers is broken, each...

Simulation of Graphene Nanoribbon based Photodetector

, M.Sc. Thesis Sharif University of Technology Faramarzi, Vahid (Author) ; Faez, Rahim (Supervisor)

Abstract

In this work, we have simulated graphene nanoribbon based photodetector and impact of changing the width, and Boron-Nitride doping and Stone-Wales defects on the optical properties of GNR has study. The energy band structure of GNR with nearest-neighbor approximation in a tight binding model calculated. To correspond with experiment and accuracy, we need to consider the impact of third nearest neighbors and edge bond relaxation. By Using the band structure, we calculated joint density of state and optical matrix elements and obtain inter band selection rule for A-GNR and Z-GNR. Then, using the Fermi’s golden rule, we investigate optical properties of GNR such as optical conductivity and...

A Simulation Study of Graphene Nanoribbon Field Effect Transistor

, M.Sc. Thesis Sharif University of Technology Samadi, Mohsen (Author) ; Faez, Rahim (Supervisor)

Abstract

In this thesis, a field effect transistor (FET) using armchair graphene nanoribbon as the channel is simulated, and the effects of changing nanoribbon width and length, as well as adding defects, are also studied. To obtain the Hamiltonian matrix and the energy band structure of graphene nanoribbon, tight binding method is used in which the first and third neighbor approximation is considered. Also, to maximize accuracy, we also considered the edge bond reconstruction. To obtain the transport characteristics of the transistor, such as the transmission coefficient and the density of states (DOS), Poisson and Schrodinger equations are solved self-consistently. We used the nonequilibrium...

Design of Graphene Spintronic Devices

, M.Sc. Thesis Sharif University of Technology Barami, Soode (Author) ; Faez, Rahim (Supervisor)

Abstract

Magnetization have an important role in spintronic devices based on graphene. In this study the effect of stone-wales and vacancy defect on electrical and magnetic properties of zigzag and armchair graphene nanoribbons were investigated. Calculations are performed using tight-binding and hubard model combining with Green's function techniques. When the balance between A and B sub-lattices gets disturbed, magnetization will be appeared. In stone-wales defect we have local magnetization because of changing the position of sub-lattices and the total magnetization is zero. In addition the stone-wales defect can change and modify the band structures and band gaps. Vacancy of carbon atom in...

, M.Sc. Thesis Sharif University of Technology Sajadian, Ali (Author) ; Faez, karim (Supervisor)

Abstract

In this thesis all the information about different techniques and methods used in Local Area Network (LAN) are described and organized as follows:
Chapter 1: The network properties are described including Network definitions and different types of LAN and their relative applications
Chapter 2 :Different techniques and protocols of data transfer and switching methods are being described and compared.
Chapter 3 : Network technology consists of different topologies for physical connections and various transfer Medias are covered.
Chapter 4 :All network protocols are described including different methods of DATA access in LOOP, RING and BUS topologies and the ISO and IEEE...

Simulation of Organic Solar Cells

, M.Sc. Thesis Sharif University of Technology Bahrami, Ali (Author) ; Faez، Rahim (Supervisor)

Abstract

Solar cells are one of the most promising clean and readily available energy sources. Organic solar cells as a new generation of solar cells, have attracted strong attention in recent years, due to the advantages of flexibility, thinness, and simple manufacturing process. This work focuses on the electrical processes in organic solar cells and approaches for enhancing the efficiency of solar cell by employing two-dimensional drift-diffusion model. At the first step. We investigate the role of different parameters such as mobility (considering different recombination mechanisms), active layer thickness, light intensity, barrier injections and energetic disorder on the performance of single...

Design and Simulation of Panchromatic Organic Photodetector

, M.Sc. Thesis Sharif University of Technology Meraji, Omid (Author) ; Faez, Rahim (Supervisor)

Abstract

Organic photodetectrors(OPD) are new generation of photodetectors that use of organic materials to convert optical signal to electrical current. Organic photodetectors in recent decade have witnessed significant improvements and many recent research allocated to this photodetectors. This OPD’s have important application so that the inorganic photodetectors have some problems in that application , for example: wide area imagination , biomedical sensors , flexible application and . . . .This work focus on the design and simulation of a panchromatic photodetector that use of new material and have high bandwidth and low dark current. One of application of this OPD is to use in optical...

Simulation and Comparative Study of Tunneling FETs Based on Graphene Nanoribbon and Phosphorene Monolayer

, M.Sc. Thesis Sharif University of Technology Almasi, Hossein (Author) ; Faez, Rahim (Supervisor)

Abstract

In this thesis, we simulate and investigate two transistors which both have tunneling FET (TFET) structure but the channel in the first one is graphene nanoribbon (GNR) and in the second one is a monolayer of phosphorene (PML). To describe the quantum systems of the transistors, we use the tight binding method and its models for the channel materials. In case of the PML TFET, based on the behavior of the phosphorene nanoribbon in different widths, we obtain a proper amount for the width to model the infinite-width channel. To extract the channel quantum transport, the Schrodinger-Poisson equations are self-consistently solved. In the next step, we simulate the GNR TFET and present the...

Modeling and Simulation of a High Power Photoconductive Semiconductor Switch (PCSS)

, M.Sc. Thesis Sharif University of Technology Hemmat, Zahra (Author) ; Faez, Rahim (Supervisor)

Abstract

There are a wide variety of light-triggered switches. Photoconductive semiconductor switches (PCSSs) have been investigated intensively for many applications owing to their unique advantages over other switches. The advantages of PCSSs make them a perfect choice for many important applications where high switching accuracy and high-power capability are required. Photoconductive switches are fabricated from a variety of semiconductors, including silicon carbide (SiC), gallium arsenide (GaAs) and gallium nitride (GaN). In Photoconductive semiconductor switches (PCSSs) the switching mechanism is initiated by optical illumination and laser source controls the flow of current. In the off or...

Simulation and Analysis Graphene Based Bio-chemical Sensor Using Localized Surface Plasmon Resonance

, M.Sc. Thesis Sharif University of Technology Tareh, Batool (Author) ; Faez, Rahim (Supervisor)

Abstract

One of the different sensing techniques for biosensors is based on surface plasmon resonance which provides high reliability and efficiency. In this project working operating principles of biosensors based on surface plasmon resonance will be examined. For investigation of sensing meachanism we assume that there an array consisting of alternating graphen ribbons which by applying light leads to an effective magnetic field coupling to the localized surface plasmon. The numerical calculations are based on the exact solution of Maxwell's equation using Fuorier Model Method and Matlab coding. In these calculations, the coefficients of transmission, reflection and absorption of light versus...

Ferromagnetic Single Electron Transistor

, M.Sc. Thesis Sharif University of Technology Asgari, Somaieh (Author) ; Faez, Rahim (Supervisor)

Abstract

This thesis completely introduses ferromagnetic single electron transistor while that identifies the application and types of the transistor.Master equation is used for simulationing of the transistor. This simulation is divided to two general sections.In the first section proposed thermal equilibrium the normal island and The two spin subsystems , however, are in thermal equilibrium and quantized nature of energy spectrum of a small central electrode and ﬂuctuations in the spin accumulation were ignored , however, we simplify the problem and assume that the charging energy are independent of the electron distribution, and number of electrons in the normal island. ،hat tunnel rates can be...