Physics - Mphil Thesis
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Item Structural and Electronic Properties of Blue Phosphorene Nanoribbons(Central University of Punjab, 2016) Ram Swaroop; Kumar, AshokExperimental discovery of graphene has opened up the door for the researcher in the field of 2D materials. After the successful synthesis of the graphene, new classes of the 2D material are emerging. Phosphorene, single layer of Phosphorous atoms, is one of those materials which was recently discovered in year 2014. In present study, we have focused on the Blue-Phosphorene nanoribbons which is one of the stable allotrope of phosphorene. Our DFT-based calculations suggest the electronic properties of blue phosphorene nanoribbons to have strong dependence on the edge structure. The passivation plays important role in the electronic properties of the Blue Phosphorene nanoribbons. In our work, we have also performed the calculations for mechanical strength, width and strain depended electronic properties of the Blue Phosphorene nanoribbons. It was found that the zigzag phosphorene nanoribbon (ZPNR) possess more mechanical strength than the armchair phosphorene nanoribbon (APNR). The electronic band gap is found to be inversely proportional to the width of the nanoribbons. On applying mechanical strain, the band gap the nanoribbon decreases and at specific high value of strain semiconductor to metallic transition occur. Our results may finds applications in Nanoelectronic devices based on the phosphorene based nanoribbons.Item Preparation and characterization of cathode material for energy storage/conversion devices(Central University of Punjab, 2016) SangeetaMetal Matrix Composites (MMCs) have evoked an intense interest in recent times for potential applications in marines, aerospace and automotive industries owing to their larger strength to weight ratio and high-temperature resistance. We have synthesized nanocomposites of (LaMnO3)1-x/(TiO2)x and (Fe2O3)1-x/(Cr2O3)x with varying concentration of TiO2 (x = 0.0-0.4) and Cr2O3 (x = 0.0-1.0). In the first chapter, includes the introduction of the metal matrix nanocomposites and their advantages. In the second chapter we have discussed about the literature review and knowledge gap. Chapter 3 involves the experimental procedure and discussion of different characterization techniques (XRD, FTIR, FESEM and EDS) used to study the prepared sample. Chapter 4 involves result and discussions obtained by characterizing the prepared sample. XRD analysis confirms the orthorhombic structure of (LaMnO3)/(TiO2) and rhombohedral structure (Fe2O3)/(Cr2O3) nanocomposites. From FESEM we have calculated the particle size for pure (LaMnO3) is 1 m and for (LaMnO3)1-x/(TiO2)x and its value decreases from 19.99- 16.91 nm with increase the concentration of TiO2 from x = 0.1-0.4. We have also calculated the band gap and refractive index from the FTIR analysis and found that gradual increase in band gap from 2.1-2.26 eV and decrease in refractive index from 2.67-2.62 as the concentration of TiO2 increases (x = 0.0-0.4). The (Fe2O3)/(Cr2O3) iv nanocomposites showed that increase in band gap 2.1-3.0 eV with decrease in particle size from 70.71-49.24 nm and refractive index from 2.67-2.44 as the concentration and Cr2O3 increases (x = 0.0-1.0.) The FTIR confirms all the functional groups present in the synthesized samples. The main application of these as- synthesized nanocomposites is photocatalysis.Item Synethesis and charcterization of nanocomposites(Central University of Punjab, 2016) Thakur, Priya; Yadav, KamleshThe Internet is global in scope and rapidly growing. With this growth, internet security threats are also increasing. The Internet is the global information exchange media, which is open and insecure, needs more and better security provision. In the era of computer network virtually all business, government and academic organizations interconnect their local area network with a collection of interconnected networks. Data transmission in a public communication system is not secure because of interception and improper manipulation by an opponent. Therefore, the attractive solution for this problem is steganography, which is the art and science of writing concealed messages in such a way that no one, apart from the sender and intend recipient, can notice the existence of the message. Thus, confidentiality and integrity principle of security can be achieved. There have been wide ranges of algorithms introduced using a text file as cover media. This thesis explains a two layered hiding technique that provides high security than other techniques. The use of local language ensures more security to the information exchange as the awareness of the local language is limited. The proposed approach uses the local language Punjabi as cover text. In proposed approach, the cover media is pre-existing media, not system generated media. Therefore, a user will be free to use the cover media taken from any Punjabi newspaper, magazine or book and the syntax of a sentence and sequence of sentence both will be true grammatically. Even though the opponent has a very good command on the Punjabi language, they will not found any suspiciousItem Synthesis and characterization of iron oxide nanoparticles(Central University of Punjab, 2016) Singh, Gurdhir; Yadav, KamleshChickpea is self pollinated legume crop which was believed firstly originated in South-Eastern Turkey and parts of Syria. Chickpea is the second most important pulse crop in the world. In Northern India, chickpea is grown in winter season. Preconditioning the plant with mild drought stress may trigger the various signaling pathways which will prepare the plants to conquer lethal cold stress. In this study, PBG1, PBG5 and GPF2 variety are more sensitive to the chilling stress, which were preconditioned with mild drought stress and then exposed to lethal cold stress. To see the effect of preconditioning various cell responses were monitored by measuring ELI, Relative Water Content and chlorophyll content at different stages of chickpea. All genotypes generated a variable response. Overall, relative water content and chlorophyll content were significantly higher in preconditioned PBG1, GPF2 and PBG5, which are sensitive to chilling stress. The study showed increase tolerance capacity in preconditioned plant towards chilling temperature and improve tolerance against chickpea.