Sharif Digital Repository

Coordination polymers are a wide range of metal-organic polymers that have good potential for use as extraction phase in solid phase extraction and solid phase microextraction. Also, these polymers can be synthesized in various morphologies such as nanorods, microspheres, nanofibers, etc. to demonstrate the effect of morphology on extraction efficiency.In this study, the extraction efficiency of a coordination polymer with two morphologies (nanorods and microspheres) and different nitrogen percentages was investigated in needle trap device using gas chromatography-mass spectrometry to measure polycyclic aromatic hydrocarbons as model analytes.PAHs were measured in conventional cigarette... 

Quantum mechanics, because of its special structure, on one hand offers us possibilities for doing un-classical tasks and on the other hand imposes limitations on performing some quantum tasks. We know these limitations as no-go theorems in Quantum mechanics. Studying these no-go theorems and properties which can be used as Quantum resources, has a wide variety of applications in Quantum information and Quantum computation, also they can lead us to a deeper understanding of the Quantum mechanics theory.One of these non-classical properties is Superposition. Quantum superposition is both a source for other Quantum properties like entanglement, and a Quantum resource for Quantum tasks. But... 

Reducing the size of transistors has dramatically increased the impacts of NBTI, HCI, and EM phenomena in comparison with decade ago. These phenomena are able to have influence on properties of different parts of a chip to make it changed gradually; including threshold voltage of a transistor and electrical conductivity of interconnections. These changes are known as the aging of a transistors that diminish the performance and reliability of a chip. A common reason that plays a significant role in all these phenomena is temperature. The temperature becomes more important when the power density increases per unit area due to decreased size of transistors, which is a trend in multi-core... 

Deposition of solid particles present in the process air on the walls of furnaces is one of the challenges in industries. This phenomenon has various causes. For example, in a furnace, the temperature of particles increases as they pass in front of the furnace burners, and due to the softening of the particles, their chances of deposition increase when they collide with the walls. Over time, with the growth of deposited particle layers on the combustion chamber walls, the performance of the combustion system gradually becomes impaired. present research aims to design air jets intersecting with the process air path, with the purpose of reducing the temperature of particles prone to deposition... 

This research aims to determine the severity of structural damage under earthquakes of varying intensities, taking into account the nonlinear behavior of structures. In recent years, identifying structural damage to prevent sudden collapse and avoid heavy human and financial losses has attracted considerable attention from researchers. Generally, the subject of structural diagnostics can be divided into localized and overall identification methods, with the overall identification approach further categorized into static and dynamic methods. In this study, a dynamic-based overall identification method is employed. Additionally, the identification of damage in large structures requires more... 

In many papers, GDP is used as a measure of economic growth, which is shown to possess a nonlinear structure. The study focuses on the nonlinear Granger causality between liquidity, government spending, oil revenues and economic growth by markov-switching vector autoregressive and markov- switching Granger causality approach for the period of 1369-1397 for Iran. The empirical results from MSAI(2)-VAR(4) suggest that Oil revenues and government spending have a significant impact on economic growth in both regimes. Also, markov- switching Granger causality results are quite different from the traditional Granger causality results, that suggests the nonlinear Granger causality has more... 

The use of microelectrode arrays in neural networks has offered a wonderful opportunity for evaluating numerous properties and interactions with excitable tissues such as the brain and spinal cord in the laboratory. In neural network applications, microelectrode arrays can be utilized to analyze nerve impulses or interact with neurons. They are either used to record neural data or to stimulate spinal cord nerves. Previous research has revealed that stimulating the spinal epidural region can help restore after spinal cord injuries (SCIs), which is the key to using them in the rehabilitation of living beings, including humans. According to the international campaign for the treatment of SCI... 

In this study, at first the V2O5 spent catalysts were characterized. The aim was to identifying whether these catalyst may be regenerated. Then, for feasibility study of them, three methods were applied: washing, diffusion and milling the spent catalysts for their subsequent reproduction. A variety of techniques such as XRD, XRF, AAS, TPR and TPO were applied in order to identify factors contributing in vanadium pentoxide catalysts deactivation. The results showed that approximately all of pollutants caused their performance deterioration, while they still have some active phases. Then, the polluted catalysts were washed (their yield increased from 43% to 72.2%). In the underside of the... 

Fabrication and characterization of different surface charged cellulose electrospun scaffolds including cellulose acetate, cellulose, carboxymethyl cellulose and quaternary ammonium cationic cellulose for biomedical applications have been reported in this research. We describe preparation of cellulosic nanofibers through the electrospinning following deacetylation cellulose acetate. Moreover, surface modification of electrospun cellulose nanofibers is carried out to obtain carboxymethyl cellulose and quaternized cellulose nanofibers, respectively. At last, the structural, morphological, mechanical, swelling, wettability and the cell culture properties of the scaffolds were analyzed and...