Sharif Digital Repository

The coupling of optical and mechanical degrees of feedom via radiation pressure has been a subject of early research in the context of gravitational wave detection. Recent experimental advances have allowed studying the modifications of mechanical dynamics provided by radiation pressure. First, this thesis reviews the consequences of dynamic back-action in optical microcavities with mechanical degree of feedom, and presents a unified treatment of its two manifestations: the parametric instability (mechanical amplification or oscillation) and radiation pressure back-action cooling. Then, by considering the Fabry-Perot cavity with two movable mirrors, and using Multi-Reflection Method, we... 

In recent years, a strong interplay between quantum mechanics and the physics of waveguide arrays was established based on a formal analogy between atomic and photonic lattices. The study of light evolution in photonic lattices has provided deep insights into the physics of wave function dynamics and, hence, peculiar quantum mechanical features. Arrays of evanescently coupled waveguides is a very versatile model system for discrete physics. Anderson localization and Bloch oscillations are two examples of coherent quantum transport phenomena, which have been investigated in this thesis. In the first part of this thesis, we investigate numerically the effect of long-range interaction on the... 

Synthesis and Investigation of Effect of Pr Doping on the Compound Y_(3-x) 〖Pr〗_x 〖Ba〗_5 〖Cu〗_8 O_(19-δ)-FInvestigation of doping of the parent compounds with different elements is important to understand the origin of high-Tc superconductivity. Several research groups have attempted to improve the properties of superconductivity and better understand the superconductivity mechanism of cuprate through doping different elements. In this research, at first, optimization of Y_3 〖Ba〗_5 〖Cu〗_8 O_(19-δ) F_z samples with z=0.2 ,0.4 ,0.6 ,0.8 ,1 ,2 ,3 ,4 have been done. By doping fluorine instead of oxygen, we expected an increase in the transition temperature, based on some the reports. But after... 

In this study new manganese(III) complexes of phox [Mn(phox)2(MeOH)2](ClO4), (phox= 2-(2` hydroxyphenyl)-5,6-dihydro-1,3-oxazine) have been synthesized and characterized with CHN,NMR and IR.The six-membered bidentate (N,O) oxazine ligand have been widely used throughout organometallic and inorganic chemistry, and are particularly important in homogeneous catalysis. The presence of N and O donor sites in oxazines may modify significantly the ligand roles for the variation of steric and electronic properties. Therefore, such systems are worth exploring for new catalytic uses . Catalytic oxidation reactions provide excellent alternatives for the use of stoichiometric reagents like urea... 

The human leukocyte antigen protein, commonly known as HLA, has the ability to present small protein fragments called peptides on the surface of cells, whether they originate from within the cell or externally. The binding of these peptides to HLA receptors is a crucial step that triggers an immune response. By estimating the affinity between peptides and HLA class I, we can identify novel antigens that have the potential to be targeted by cancer therapeutic vaccines. Computational methods that predict the binding affinity between peptides and HLA receptors have the potential to expedite the design process of cancer vaccines. Currently, most computational methods exclusively rely on... 

A lot of efforts to make CMOS integrated wireless systems have been made in the past few years. One of the most challengeable parts of wireless systems is power amplifier designing with high output power (Watt Level). Power amplifier linearization and efficiency are the most important parameters. Today, high linear and efficiency power amplifier designing is one of the most important designer challenge of integrated circuits in wireless networks. Generally, there is one inverse relation between linearization and power efficiency. So, circuit and system solutions have been suggested that high efficiency nonlinear switching power amplifier with linearization techniques and linear power... 

This thesis presents a new approach to probabilistic seismic hazard analysis. Hazard in this context means the probability of exceeding a measure of earthquake intensity. The main components of the proposed approach are twofold: 1) Reliability methods compute the exceedance probabilities; 2) Multiple probabilistic models compute the earthquake intensity. These two components are presented in details. The proposed methodology is employed in a comprehensive seismic hazard analysis of Iran with an area of nearly 1.65 million square kilometers and 112 sources of seismicity. In this analysis, a grid of 2045 points is chosen to produce a high resolution hazard map. The analysis is carried out for... 

From 1990’s the Cosmological Constant Problem was brought back to spotlight and physicists have tried to find out its source. But the value that particle physic anticipates for cosmological constant is not harmonic with cosmological considerations. This thesis investigates the studies in this field  

Detecting small particles is one of the needs of researchers. Industrial and research developments in nano and biotechnology expands the need of suitable equipments. One of the challenges in this field is detecting the qualitative and quantitative properties in the sample. Until today there are numerous methods to detect the properties of the particles and different commercial machines are presented for this purpose. In this method, based on one the methods of detecting particles, called resistive pulse sensing, a mechanism is composed and by its help 7 um and 800 to 2000 nm particles are distinguished separately. This sensor has two important parts: the fluid and the electronic. In the... 

Blockchain technology presents a decentralized management structure designed to cater to various needs, such as decentralization and the elimination of single points of failure. With the evolution of blockchain technology, smart contracts have emerged as a remarkable platform for facilitating financial activities in a decentralized manner. Among the different types of smart contracts, decentralized exchanges stand out by their absence of a central authority overseeing user transactions. This lack of a central oversight exposes users of such exchanges to potential attacks from malicious entities. A key challenge faced by these exchanges is the concept of Miner Extractable Value. Miner... 

In recent years, lots of efforts has been done to implement Ultra-Wideband (UWB) Low Noise Amplifiers (LNAs), and Reconfigurable Low Noise Amplifiers, to achieve low Noise Figure (NF) and power dissipation, and high gain and linearity. In this thesis an Ultra-Wideband CMOS Low Noise Amplifier is presented. Due to really low power consumption and extremely high data rates, the UWB standard is popular in the consumer market. The LNA is the outer most part of an UWB transceiver, which provides enough gain to the signal with the least possible noise and distortion. 0.18u CMOS technology has been chosen for the design of the LNA at the transistor level. Two different bandwidths in a single LNA... 

The main purpose in this study is the determination of offshore structures reliability index over time by considering the simultaneous effects of natural hazards. Importance of this study stems from the effect of events associated with time which induces high amount of uncertainties on offshore structures performance during their life time. Extreme wave, marine current, earthquake, fatigue, corrosion and marine growth hazards are considered in this paper. The intensity and occurrence time of all hazards are time dependent parameter. In addition some of these hazards have the possibility to coincidence and the interaction effect. Whereas, the previous studies in this field, the effect of each... 

This thesis studies the effect of soil-structure interaction on the seismic performance of structures with due account of uncertainties. The motivation for this study stems from the significant uncertainty in the earthquake ground motion and in the properties of the soil and the nonlinear behavior of the structure. The soil-structure system is modeled by the sub-structure method. The uncertainty in the properties of the system is described by random variables that are input to this model. Monte Carlo sampling is employed to compute the probability distribution of responses that describe the seismic performance of the structure, such as the ductility demand. In each sample, a randomly... 

This thesis revisits the effect of dynamic soil-structure interaction (SSI) on multistory buildings with a probabilistic approach. For this purpose, the relationship between the strength demands of fixed- and flexible-base multi-degree-of-freedom (MDOF) systems, or strength reduction factor thereof, with that of fixed- and flexible-base equivalent single-degree-of-freedom (eSDOF) systems is investigated considering prevailing uncertainties. To this end, Monte Carlo sampling analysis is employed in which a suite of nearly 2000 records are utilized to properly quantify the ground motion uncertainty. The soil-structure system is modeled by the sub-structure method. The uncertainty in the... 

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... 

In 1917 Einstein used Λ as a cosmological constant in his theory of general relativity, but after a while he receded for some reasons. This constant has been reconsidered again recently. But using it in general relativity has caused some problems. In this thesis, after a short review of important elements in studying cosmological constant problem, like a short introduction to general relativity and cosmology in the first chapter as well as a short review of quantum field theory and supersymmetry in the second chapter, we will study the history and introduction of the problem in the third chapter.in the third chapter , different solutions to this problem ,like supersymmetry,anthropic... 

The primary objective of this thesis is twofold: First, the effect of soil-structure interaction (SSI) and SSI seismic design provisions on the seismic risk estimates of buildings are studied. Risk, in this context, denotes the probability distribution of seismic monetary loss due to structural and non-structural damage. The risk analysis here uncovers the probability that SSI is beneficial, detrimental, or ineffective on seismic losses. Moreover, the consequence of practicing SSI provisions of current seismic codes on the seismic risk of structures is investigated. Second, the consequences of practicing the SSI provisions of two prominent seismic design guidelines, i.e., ASCE 7-10 and the... 

This paper proposes a novel probabilistic approach to account for soil-structure interaction (SSI) in the seismic design of building structures. In this approach, an SSI response modification factor, RSSI, is introduced to capture SSI effects on the seismic performance of structures. The proposed procedure quantifies RSSI such that the probability distribution of the collapse capacity of the structure designed to account for SSI concurs with that of the structure designed using the default fixed-base provisions. The proposed approach is employed for special steel moment frame buildings with surface foundation. A surrogate single degree of freedom (SDOF) system is developed in this study and...