Sharif Digital Repository

Capturing the atmospheric CO2 and turning it into value added products is a topic that has been extensively studied in recent years. One of the methods through which CO2 is valorized is via converting it into carbon nanofiber, CNFs. CNFs can be an important material in future human activities due to its valuable properties such as wide range of electrical conductivity, their superior flexibility and strength, But it is currently obstructed in use due to the high cost of manufacturing and the complexity of the synthesis. Furthermore, in today's world, human life is heavily influenced by greenhouse gases, and avoiding emitting gases like CO2, is almost infeasible. This thesis provides an... 

In this project alumina-zirconia-ceria nanocomposite with 80% mol alumina (0.2Ce0.1Zr0.9O2-0.8Al2O3) was produced by solution combustion synthesis method. In the mentioned method, optimal fuel with composition of 75% urea, 25% ammonium acetate, and stoichiometric amount of glycine (0.75U-0.25AA-1G) was used. Moreover, ammonium nitrate as aid combustion was added to optimal fuel. In order to calcinations, nanopowder obtained from combustion synthesis was heated to 500°C for 1 hour and kept at this temperature for 2 hours. To complete heat treatment, the nanopowder was heated to 1150°C for 2 hours and 10 min and kept at this temperature for 2 hours. Then the specimens were pressed at pressure... 

Syntheses of coats including nickel nano-particles by electrodeposition have been
investigated for over 10 years. A method of testing according to surface reply was chosen
to reveal the effect of each pulse parameters (including duty cycle, frequency, average
current density, off time (toff) and on time (ton)) and the effect of saccharin concentration
on electroplating cathode efficiency, nanostructure. Pulse electroplating test of nickel was
composed by 30 tests. Pulse electroplating with relatively high peak current density was
employed and saccharine was added to increase deposition and rate of nickel nucleation on
surface. According to the results of cathode... 

Rhenium(I) tricarbonyl complexes with NN-donor ligands display promising properties for potential applications as molecular catalysts for the reduction of carbon dioxide and as biocompatible pro-drugs for the controlled release of carbon monoxide. In this context the diimine type ligands are one of the most widely used bidentate chelating moieties. In this work, several [Re(CO)3(DAB)X] complexes were prepared in a standard manner by replacement of two cis CO groups in the starting bromo- or chloro-pentacarbonylrhenium complexes with 1,4-diazabutadiene (DAB) ligands. Their pseudo-octahedral facial structures were established using FT-IR, 13C-NMR and 1H-NMR and confirmed by X-ray... 

In the classical theories of plasticity, plastic deformation of material is modeled with a macro- scopic viewpoint and without considering the existing physical mechanisms at the crystal scale. However, plastic deformation stems from slip phenomena and evolution of crystalline structure. Furthermore the effects of initial texture of material on its mechanical properties, like formability, and also texture evolution of material can only be calculated by considering these physical mecha- nisms.The main purpose of this thesis is to predict forming limit diagrams of sheet metals based on crystal plasticity approach by considering the effect of initial material texture and presentation of... 

In this study, synthesis structural and theoretical studies of four rhenium tricarbonyl complexes with 3-cyanobenzaldimino ethylenediamine (3CNbzen) and 2,3,6,7-tetraphenyl-1,4,5,8-tetraazaphenantherene (Ph4TAP) were investigated. The synthesized complexes were characterized by spectroscopic methods and their solid-state structure were determined by single-crystal X-ray diffraction analysis. Using single-crystal X-ray diffraction structure, the intra- and intermolecular interactions of the complexes and their dimers resulted from X-ray Cartesian coordinates were investigated. Furthermore, computational approaches were carried out to confirm the existence of the intra- and intermolecular... 

X-ray radiation is an ionizing radiation that can be produced under some conditions in an ion implanter and can have significant effects on equipment and personnel health. In this dissertation, we first examine the properties of ionizing radiations and their effects of electronic devices and discuss the general properties of common detectors. Next, Using Silvaco TCAD and GEANT4 we will simulate the interaction of ionzing radiation with energies up to 300 keV with electronic devices including a commercial off the shelf photo diode and a specialized x-ray detector and show that these devices can efficiently reveal informations of a radiation source to the user. Also, it has been shown that... 

A soft X-ray spectrometer based on Johann's method and an embedded curved crystal is designed and fabricated for Sharif University of Technology's Plasma Focus (SUT-PF) in this project. Focusing rays with the same wavelength at a point to increase the ray intensity is the reason of choosing the cylindrical curved crystal spectrometer since its performance is inspired to the Bragg's law.The optimal conditions for SUT-PF (pressure and voltage) is adjusted and examined by photodiode detector and the camera pinhole before spectroscopy experiments. The diameter of generated hot spots is measured as 80 microns in the optimal condition.The recorded spectral lines on the radiography film and the... 

Cold plasma due to its special properties has many applications in the microelectronics industry. At the beginning of this study, a few examples of widely used plasmas and the requirements for driving their power sources have been investigated. To generate and characterize plasma, various topologies of DC power supply construction, including high-voltage low-current power supplies called multipliers and low-voltage high-voltage power supplies called converters, have been reviewed and compared.Circuit for pulse generating for plasma application has also been proposed and investigated. In the simulation section, after introducing, reviewing, and compareing the common types of simulators, the... 

Designing a system based on 2 to 5 MeV electron accelerators for X radiation of urban waste.Nowadays , the use of ionizing radiation in two cases of treatment and removal of contaminants in the waste including; 1) Pathological hospital waste 2) leachate from buried urban waste, which is studied and examined in this project. Buried urban wastes begin to break down under aerobic and anaerobic processes, and as long as the materials are not changed into sustainable materials, these processes will continue and results in landfill gas and leachate. Gas is produce due to anaerobic processes and leachate which is produced through water infiltration (atmospheric precipitation) in the landfill or... 

Although studies have shown interesting piezoelectric and dielectric properties of PZT containing composite piezoelectric ceramics, there has been no systematic investigation on the PZT-PCN, especially on the porous one.In this study, the dense ceramics of 0.8Pb (Zr1/2Ti1/2)O3–0.2Pb(Co1/3Nb2/3)O3 abbreviated to (PZTCN) systems were successfully prepared by the columbitewolframite precursor method via the mixed oxide technique. Porous PZT-PCN ceramics were prepared by burnable plastic sphere process (BURPS) technique with three types of pore forming agents (PFAs), poly vinyl chloride (PVC), stearic acid (SA), and poly methyl methacrylate (PMMA) at different weight percentages(5, 10,and 15... 

The g-C3N4/Fe2O3 nanocomposite was produced by the combustion synthesis. The product was characterized by x-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller study (BET), Ultraviolet-visible analysis (UV-vis) and photoluminescence measurement (PL). Effect of iron nitrate on stability and photocurrent density under simulated visible-light irradiation was determined. The highest photocurrent density obtained (4.25 μA/Cm2) was twelve times the pure g-C3N4. This improvement was due to a bandgap decrease, the specific surface area increase, reduction of the electron-hole recombination, and... 

In this research, the surface of multi-walled carbon nanotubes (CNTs), as template, were coated by Lead zirconate titanate (PZT) with composition of Pb(Zr0.52Ti0.48)O3 via sol-gel process. The final product is called PZT-CNT hybrid material. For functionalizing of CNTs, benzyl alcohol was used. Simultaneous thermal analysis (STA) proved that the as-derived amorphous material crystallized at 520 ˚C. Scanning Electron Microscope (SEM) images verified the deposition of a uniform coating of PZT on the surface of CNTs and proved that the functionalizing treatment was done successfully. X-ray diffraction (XRD) showed that the crystal structure of the hybrid was tetragonal perovskite.... 

In this project, synthesis of sol-gel derived Pb(Zr0.52Ti0.48)O3 nanotubes in the form of PZT-CNT hybrid, was accomplished by using multi-walled carbon nanotubes as sacrificial template. Simultaneous thermal analyses proved that the as-derived amorphous material crystallized at a significantly low temperature by a considerably low activation energy. X-ray diffraction and selected area electron diffraction patterns showed that the final crystal structure is tetragonal perovskite. Raman spectroscopy results proved that significant changes happened at the surface of carbon nanotubes which are believed to be due to coating. Electron images supported the deposition of a coating on the surfaces of... 

In the first part, two copper(I) complexes were synthesized as additive products of nitrogen-donor, phosphine and stibine ligands and copper(I) iodide, and in the second part, the triple-core copper(I) complex was synthesized with a phosphine ligand. The synthesized complexes were identified by FT-IR, 1H-NMR, 31P-NMR spectroscopy and the structure of these complexes was investigated using single crystal X-ray diffraction. In addition, the possibility of Cuprophilic interactions using structural parameters, And theoretical studies were reviewed. On the other hand, molecular structure determination allowed us to fully investigate the intramolecular and intermolecular interactions of the... 

In this study first some new diimine ligands were synthesized, then mononuclear and binuclear Cu(I) complexes with starting matrials, [Cu(NCCH3)4]X (X= PF6, ClO4) or CuI, and the synthesized diimine ligands and phosphinic (POP) ligand were prepared. These complexes were characterized using 1HNMR, 31P{1H}NMR, and FT-IR spectroscopic methods and their solid state structure were determined by single crystal X-ray diffraction. Inspection of the solid-state structurs, showed variety of the stabilizing interactions shuch as NO2•••NO2, π•••π, C─H•••π, and NO2•••π. Density functional theory (DFT) was used for geometry optimization of the singlet states in gas phase and the electronic structure... 

In this study, a number of complex cobaloxim complexes [Co(DMG)2LX] in which L= 4-MePy, 3-MePy, 4-bzPy, 3-CNPy, 4-CNPy, tBuPy, styPy, NaphPy synthesized and their structure studied. These complexes were identified by FT-IR and 1H NMR methods as well as their solid state structure studied by X-ray crystallography of single crystals. Gaussian 09 software was used to optimize the geometric structure and obtain the vibrational frequency of cobalt complexes. Charge decomposition Analysis (CDA) and molecular orbital studies were performed using the AOMix 6.88 software. Also, the characterization of σ-donating and П-acceptoring of pyridine ligands in these complexes was investigated using... 

The synthesis, characterization, structural and computational studies of mononuclear Re(I) tricarbonyl complexes of 2,2'-bipyridine (2,2′-bpy) and 2,9-dimethylphenanthtroline (2,9-Me2Phen), [Re(CO)3(NN)(X)], where NN=2,2′-bpy,X=Br (1) and X=–ONO (3); NN=2,9-Me2 Phen, X=Br (2) and X= –ONO (4), were reported. The complexes characterized by crystallographic and spectroscopic methods and elemental analyses. In each complex, the Re(I) center showed the distorted octahedral geometry. Single crystal X-ray diffraction data revealed the endo-nitrito (κ1–ONO) coordination in complexes 3 and 4. It has been shown that the replacement of the bromo ligand in complexes 1 and 2, either by AgOTf/NaNO2 in a... 

Electrical arc discharge in ambient air, vacuum, reactive gas and other environment is an appropriate method for synthesis of different nanostructures. This method can provide stable and ultra pure nanostructures with diverse applications. In this research we focus on synthesis and analysis of titanium nitride nanoparticles in liquid nitrogen(lack of oxygen)by Electrical arc discharge . At the beginning a reactor for the electrical arc discharge process designed and implemented. Titanium nanoparticles have synthesis by this method analyzed. Several characterization techniques such as X-ray diffraction (XRD), dynamic light scattering (DLS), X-ray photo electron spectroscopy (XPS), scanning...