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Total 258 records

    Smulation of Hydrogen Production by the Process of Thermal Decomposition of Methane

    , M.Sc. Thesis Sharif University of Technology Parishan, Samira (Author) ; Saboohi, Yadollah (Supervisor)
    Abstract
    Different disadvantages associated with using fossil fuels as the main energy source including crisis of wells’ depletion and serious environmental problems, causing by the emission of large quantities of greenhouse gases (GHG), especially carbon dioxide (CO2), has increased attention to replacing them with renewable and clean fuels such as wind, solar, and geothermal energy sources. Hydrogen, as a clean energy carrier, is one of the best fuels in terms of the environment and cost. So, it is recently receiving increasing attention and it may one day replace fossil fuels for various applications such as in automobiles and power stations. The main subject of this thesis was surveying the... 

    Modeling Two-Dimensional Face from DNA Using the Face Embedding Approach in Deep Learning

    , M.Sc. Thesis Sharif University of Technology Mirzaei, Mohammad Amin (Author) ; Hossein Khalaj, Babak (Supervisor)
    Abstract
    the purpose of this research is to construct the facial image of a person from corresponding DNA. In this problem, we have a set of DNAs and facial images and we want to find the relation between the DNA and the features of facial images.using this relation we can find the facial Image of a person using the DNA. for this purpose we should first extract the features of faces that have the most variation among the population. by studying the feature extraction methods in this field, we borrow the deep neural network method that is used in face recognition fields.we found significant relations between DNA and extracted features from this network. finally using this relation we can predict the... 

    Design, Simulation and Fabrication of Integrated Centrifugal Microfluidic Platform for Separation and Lysis of Circulating Tumor Cells

    , M.Sc. Thesis Sharif University of Technology Momeni, Maede (Author) ; Shamloo, Amir (Supervisor) ; Firoozbakhsh, Keykhosrow (Supervisor)
    Abstract
    Cancer diagnosis area has recently been in the limelight of the medical research and there exist an unremitting focus on the devices & technologies which enable cancer detection in its victims. Lately a genius diagnostic method based on isolation and entrapment of circulating tumor cells has been developed which pave the path for cancer identification. These circulating cells which are detached from the primary tumor are carried out through body by means of circulation system. They play key role in phenomenon called metastasis. Separating these rare cells from multifarious background blood cells, assessing their quantity can supply valuable information on the stage of disease as well as its... 

    Design, Simulation and Construction of a Rapid Gene Amplification Microfluidic Device Using Polymerase Chain Reaction (PCR) Method

    , M.Sc. Thesis Sharif University of Technology Amadeh, Ali (Author) ; Shamloo, Amir (Supervisor)
    Abstract
    Polymerase chain reaction method is a conventional method for obtaining multiple copies of a specified segment in the DNA molecule and to amplify the DNA molecule itself. Therefore, this method has been of paramount importance in different fields of research and has been applied for different applications. PCR requires thermal cycling, or repeated temperature changes between two or three discrete temperatures to amplify specific nucleic acid target sequences. To achieve such thermal cycling, conventional bench-top thermal cyclers generally use a metal heating block powered by Peltier elements or benefit from forced convection heat transfer. Although efforts have been made in order to reduce... 

    Investigation of the Influence of Geometry and External Field on Fluid Flow Through Carbon Nanotubes by Molecular Dynamics Simulation

    , M.Sc. Thesis Sharif University of Technology Khodabakhshi, Milad (Author) ; Moosavi, Ali (Supervisor)
    Abstract
    Water transportation through carbon nanotubes is key for designing nanodevices. The directed transport of water molecules through a rotating charged carbon nanotube (CNT) is investigated by molecular dynamics simulations. It is found that the net flux of continuous unidirectional water flow depended sensitively on the charge distribution, charge density and rotation of the CNT. we find that for a constant charge density, the water flux increases with the increase of the charge difference. Besides, we find that the water flux shows a nonlinear dependence on the angular velocity of the rotation. The rotation of the CNT with low angular velocities, can not generate a continuous water flux. The... 

    Diffusion of Lipid and Protein Molecules in Cell Membranes

    , Ph.D. Dissertation Sharif University of Technology Khoshnood, Atefeh (Author) ; Jalali, Abbas (Supervisor)
    Abstract
    Lipid membranes are fundamental constituents of cell membranes and are now used in lap-on-a-chip technology. Membranes in living cells contain a significant fraction of proteins, which undergo lateral random movements due to thermal fluctuations and shear forces imposed by the solvent fluid. Prominent natural and biotechnological systems where membranes are highly sheared include the plasma membrane of endothelial cells, and membranes used in biosensors for high throughput screening of drug candidates, and in water purification devices. In these systems membrane is in direct contact with the mainstream suspension flow, which is driven by pressure gradients. The efficiency and function of... 

    Study, Optimization and Construction of a Microfluidic Gene Amplification Device by Using Thin Film Layer Method

    , M.Sc. Thesis Sharif University of Technology Eslami, Sara Sadat (Author) ; Vosoughi, Manouchehr (Supervisor) ; Alemzadeh, Iran (Co-Supervisor) ; Shamloo, Amir (Co-Supervisor)
    Abstract
    Polymerase Chain Reaction (PCR) is a process in which a special piece of a gene is amplified millions of times over a short period. This method has been of paramount importance in different fields of research and has been applied for different applications. PCR requires thermal cycling, or repeated temperature changes between two or three discrete temperatures to amplify specific nucleic acid target sequences. To achieve such thermal cycling, conventional bench-top thermal cyclers generally use a metal heating block powered by Peltier elements or benefit from forced convection heat transfer. Due to the fact that these methods are time consuming, it seems that design and fabrication of a fast... 

    Molecularly Imprinted Polymers for the Treatment of Disease

    , Ph.D. Dissertation Sharif University of Technology Nematollahzadeh, Ali (Author) ; Abd Khodaei, Mohammad (Supervisor) ; Shojaei, Akbar (Supervisor)
    Abstract
    In the present investigation, experimental design, synthesis and evaluation of Verapamil, Albumin, Immonuglubline G and Trypsin imprinted polymers and finally Albumin imprinted poly(dopamine) nano-layer were presented. A bimodal polymerization approach as a combination of precipitation and dispersion polymerization was taken towards producing 500 nm particles for verapamil imprinting purpose. In this case the imprinting factor was 2.17. In a challenge for producing spherical particles with predefined size and pore properties the hierarchical polymerization in packed beds, using porous silica particles (particle size ca. 40 µm) was developed, as well. The method resolving the problems... 

    Design and Simulation of CMOS Based Magnetic Sensor for Biosensing Applications

    , M.Sc. Thesis Sharif University of Technology Mafi, Alireza (Author) ; Akbari, Mahmood (Supervisor) ; Fotowat-Ahmady, Ali (Supervisor)
    Abstract
    This paper presents a scalable and ultrasensitive magnetic biosensing scheme based on on-chip LC resonance frequency-shifting. The sensor transducer gain is demonstrated as being location-dependent on the sensing surface and proportional to the local polarization magnetic field strength |B|2 generated by the sensing inductor. To improve the gain uniformity, a periodic coil is proposed as a substitution for the standard process coil. As an implementation example, the circuit is designed in a 65nm CMOS process. The spatially uniform sensor gain of the array is verified by COMSOL simulations. Overall, the presented sensor demonstrates an improvement in the uniformity of the inductor’s magnetic... 

    Measurement and Characterization of Electric Current in Metallic-DNA Bundles

    , M.Sc. Thesis Sharif University of Technology Sobhani Khakestar, Ali (Author) ; Fardmanesh, Mahdi (Supervisor) ; Hejazi, Mohammad Saeed (Supervisor)
    Abstract
    DNA is big protein molecule consisting of two strands intertwining each others. Recently DNA molecule has drawn attention of researchers to be used in electronic circuits and molecule electronic field. Therefore, many experiments have been carried out to measure DNA conductivity in different temperature in single molecule or bundle mode with varying size and shape. In this thesis, metallic bundle DNA at normal room temperature is studied and their resistance characteristic is obtained and compared. In order to improve DNA conductivity Metal Ions like zinc are adulterated to each of its structure period. DNAs with these metallic impurities are called metallic DNAs.
    Thus, golden electrodes... 

    Generation and Optimization of High-order Harmonics in the Interaction of Laser with N2O Molecule

    , M.Sc. Thesis Sharif University of Technology Monfared, Mohammad (Author) ; Sadighi-Bonabi, Rasoul (Supervisor) ; Irani, Elnaz (Co-Supervisor)
    Abstract
    The X-ray attosecond pulses have many useful applications for studying atomic and sub-atomic scales phenomena in attosecond scale duration. Generation and optimization of high-order harmonics is an efficient way to produce such attosecond pulses which are studied in this thesis. There are several limitations in the attosecond pulse generation such as low efficiency of high-order harmonics, long duration of output pulses and the impossibility of producing an attosecond pulse with any desired wavelength in the x-ray region. Therefore, more investigations into high harmonic generation and fully control and optimization of this process is significant. In this thesis, high harmonic generation... 

    Molecular Dynamics Study in the Interaction of Intense Femtosecond Laser Pulse with Methane Molecule

    , Ph.D. Dissertation Sharif University of Technology Irani, Elnaz (Author) ; Sadighi-Bonabi, Rasul (Supervisor) ; Anvari, Abbas (Co-Advisor) ; Asgari, Reza (Co-Advisor)
    Abstract
    In this project, the ionization and dissociation of methane molecule by intense femto-second lasers has been studied. Dissociation probability is calculated for interacting CH4 molecule under Ti: Sapphire laser pulse with pulse durations of 10- 40fs in intensities at the range of 1014-1016 Wcm-2. Calculations are carried out with time-dependent density functional theory using Gaussian03 and Octopus packages as powerful computational chemical physics programs. Due to importance of the dependence of interaction dynamics to laser parameters, the effect of these parameters including different intensities, polarization, various pulse durations and pulse envelopes are investigated. The optimal... 

    Ionization and Dissociation of the Chlorine Molecule by the Femtosecond Ti: Sapphire Laser Radiation

    , M.Sc. Thesis Sharif University of Technology Mostafaei, Anahita (Author) ; Sadighi-Bonabi, Rasoul (Supervisor)
    Abstract
    Ionization probability of Cl2 molecule is studied by irradiation of 800 nm Ti: Sapphire laser pulses at intensities of 1014 Wcm-2 to 1016 Wcm-2 with the Gaussian package. Molecular orbital symmetry and orientation of the molecule dipole moment with laser field polarization axis are very effective in ionization probability. The results show that the most ionization probability for the intensity of 1014 wcm-2 is at 900 and also 50 at intensity of 1016 wcm-2. Due to the lack of intrinsic dipole moment, variation of dipole moment with the intensity, bond length and time evolution of dipole moment are investigated. It is found that there is a linear dependance of these parameters with ionization... 

    Separation of Hydrogen Molecule from Methane Molecule by Intense Femtosecond Laser Pulses

    , M.Sc. Thesis Sharif University of Technology Moeini Alishah, Hamed (Author) ; Sadighi Bonabi, Rasoul (Supervisor)
    Abstract
    Conversion of Methane molecule to valuable heavier hydrocarbon and hydrogen by using of short pulse lasers is investigated. The dynamical information of molecule such as orientation, dipole moment variations with binding length, and potential energy levels are initially produced by using Gaussian software. Based on this information the Schrödinger wave equation for this polyatomic molecule is numerically solved. Then by selecting the various laser parameters and installing of them in the Hamiltonian of the mentioned system, the dependence of hydrogen transition and separation probability on these parameters are investigated. In this work by radiating of the laser beam along the C2 symmetry... 

    Study of Surface Growth of Organic Thin Film

    , M.Sc. Thesis Sharif University of Technology Hosseini, Hadi (Author) ; Rahimi Tabar, Mohammad Reza (Supervisor)
    Abstract
    In recent decades the Due to development of coating techniques and the diversity of high organic matter, Discussion of organic coating materials being raised. Moreover, because of many applications of organic thin film in electronic and optical systems for example OTFTs and OLEDs Organic thin film growth topic is very interesting for scientists. Among these, some scientists study the theory and another bunch of scientists pay to practical aspects of this topic. In this thesis I pay to the theoretical level of Organic thin film growth and I simulate the system includes a collection of molecules, Went on to study some statistical properties of the system will be discussed and the dynamic... 

    Survying the Process of Photodissociation of Methane with Using the Femto Second Lasers

    , M.Sc. Thesis Sharif University of Technology Irani, Elnaz (Author) ; Sadighi Bonabi, Rasoul (Supervisor)
    Abstract
    In this project , the dissociation of methane in the presence of Ti:Sapphire laser with parameters of 1014wcm-2, 800nm wave lengths and 100fs pulse width have been investigated theoretically, by using the Gaussian03 package –computational chemistry program that is capable of predicting many properties of atomic and molecular systems. It is based upon the fundamental laws of quantum mechanism. By considering some limitations in approximate techniques and incapability of advancing them, numerical calculation of solving the time dependent Schrödinger equation in order to improve the results and find more quantum dynamic information is applied. Therefore at first, by Gaussian03 package some of... 

    Theoretical Investigation of Hydrogen Bonding Effects on Acidity Enhancement of Alkyl sulfonic Acids and Hydroxy Alkyl Sulfonic Acids in Gas and Solution Phase

    , M.Sc. Thesis Sharif University of Technology Najdian, Atena (Author) ; Fattahi, Ali Reza (Supervisor) ; Hormozi-Nezhad, Mohammad Reza (Supervisor)
    Abstract
    Hydrogen bonding is an important weak interaction encountered in gas, liquid, as well as solid phases. The hydrogen bond plays a very vital role in many life processes and is one of the most frequently used terms in chemistry and biology.
    Polyols or polyhydric alcohols are, strictly speaking, simply organic chemicals containing more than two hydroxyl groups. Each hydroxyl is attached to separate carbon atoms of an aliphatic skeleton.They may also contain ester, ether, amide, acrylic, metal, metalloid and other functionalities; along with hydroxyl groups. Polyols are obtained from many plant and animal sources and are synthesized by a variety of methods. Among important properties of... 

    Influence of Intramolecular Hydrogen Bonding on Ability of Leaving Group in SN2 Reactions

    , M.Sc. Thesis Sharif University of Technology Ahmadi, Aliakbar (Author) ; Fattahi, Alireza (Supervisor)
    Abstract
    Many of the significant reactions in chemistry and biology are related to bimolecular nucleophilic substitution (SN2) reactions which have been studied first by Hughes and Ingold in the 1930s. Afterward, many organic chemists have continued this work. Up to now, numerous experimental kinetic and theoretical researches have studied the mechanism of these reactions. Since most SN2 reactions occur in solution, a large number of these studies have been devoted to the solvent effects. One of these effects that has been examined extremely is H-bonding via protic solvents that lowers the energy of an anionic nucleophile relative to the transition state, in which the charge is more diffuse, and... 

    Classification, Similarity Analysis and Modeling of Drug Activities Using Chemometric Techniques: Introduction of Classical Relativity in Chemical Space

    , Ph.D. Dissertation Sharif University of Technology Mani-Varnosfaderani, Ahmad (Author) ; Jalali-Heravi, Mehdi (Supervisor)
    Abstract
    The present research devoted to the application, development and implementation of clustering, classification and regression techniques for modeling of the biological activity of different drug and drug-like molecules. At first, the prediction ability of Bayesian regression techniques was evaluated for describing and predicting the inhibition behavior of Integrin antagonists. As a next step, the complementary local search techniques have been used for improving the performances of Bayesian regularized genetic neural network (BRGNN) algorithm. The results indicated that the pattern search algorithm has a great potential to be used as a feature selection method in Chemoinformatics. In line... 

    Synthesis and Properties of Cationic Polynulcear Complexes of Manganese with the Anionic Keggin Type Polyoxometalates as Single Molecule Magnets Hx[Mn4O2(CH3COO)7(bipy)2]n[Kegiin-Polyoxometalates]m.yH2O

    , M.Sc. Thesis Sharif University of Technology Daneshmand Kashani, Pargol (Author) ; Mohammdi Boghaei, Davar (Supervisor)
    Abstract
    Single molecule magnets due to their magnetic tunneling effect and the interaction they have with an external magnetic field are used widely in quantum computing and also the storage of data with high capacities. Polyoxometalates that are used as counter ions for cationic single molecule magnets, are able to affect their spin-couple nature via a magnetic exchange and also have an influence on the crystal accumulation in order to change the magnetic property of the molecule. In this research the probability of sedimenting a cationic single molecule magnet, [Mn4O2(CH3COO)7(bipy)2]+, with the use of anionic polyoxometalates with Keggin structures has been investigated. Thus, the single...