JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech III Year NANO MATERIALS Previous Question Paper (February - 2023 - R18)
Note: i) Question paper consists of Part A, Part B. ii) Part A is compulsory, which carries 25 marks. In Part A, Answer all questions. iii) In Part B, Answer any one question from each unit. Each question carries 10 marks and may have a, b as sub questions.
Part A
What are the medicinal uses of Colloidal gold?
Answer
Colloidal gold is primarily used in medicine for diagnostic and therapeutic applications. Its key uses include:
- Diagnostic Imaging and Biosensing: Due to its localized surface plasmon resonance (LSPR) properties, colloidal gold is used as a contrast agent in medical imaging and as a label in lateral flow assays, such as rapid diagnostic tests for infectious diseases.
- Targeted Drug Delivery: Gold nanoparticles act as biocompatible carriers for the site-specific delivery of therapeutic agents, including genes and anti-cancer drugs, to tumor cells.
- Photothermal Therapy: Colloidal gold particles can absorb near-infrared light and convert it into heat, which is used to selectively ablate cancerous tissues while minimizing damage to surrounding healthy cells.
What are zero-dimensional nanostructures? Give examples with typical range of dimensions.
Answer
Zero-dimensional (0D) nanostructures are materials in which all three dimensions of the object are confined at the nanoscale, typically within the range of 1 to 100 nanometers. In these structures, there is no degree of freedom for free electron motion, leading to quantum confinement effects that significantly alter the material's physical, optical, and electronic properties.
Common examples include:
- Quantum dots: Semiconductor nanocrystals with dimensions typically between 2 nm and 10 nm.
- Nanoparticles: Metallic or ceramic particles, such as gold or silver nanoparticles, usually ranging from 1 nm to 100 nm.
- Fullerenes: Carbon-based molecules like C60, which have a diameter of approximately 1 nm.
What are quantum dots? Mention the properties of quantum dots.
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How the metallic nanoparticles are prepared by electrochemical deposition method?
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What is meant by “anisotropic growth” in nanowire formation?
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What is the mechanism of crystal growth according to Burton, Cabrera and Frank (BCF) theory?
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Define Epitaxy process of single crystal growth. How this process is classified?
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What is the principle and applications of Molecular beam epitaxy (MBE) method?
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What are carbon nanotubes? Summarize the properties and applications.
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Summarize the requirements for precursors used in Atomic layer deposition (ALD) method.
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Part B
Discuss the applications of nanomaterials in semiconductor industries.
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Explain the principles of top-down and bottom-up approach for nanomaterial synthesis.
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Elaborate the technical challenges faced in the fabrication and processing of nanomaterials and nanostructures.
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What are nanobots? List the applications of nanobots.
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Explain the importance of “overall Gibbs free energy” in homogenous nucleation process.
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Discuss the size distribution of nanoparticles when growth of nuclei is controlled by surface process.
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Discuss the fundamentals of heterogeneous nucleation process on a planar solid substrate.
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Explain the formation of nanoparticles by aerosol method.
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Explain the synthesis of nanomaterials by Evaporation-condensation growth method.
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Discuss the important conclusions of Wagner theory for Vapor – liquid – solid (VLS) growth process.
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Discuss the principle and applications of Electrophoretic deposition method and Electro chemical deposition method.
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With a schematic diagram, explain the Frank – van der Merwe growth mode and Stranski – Krastonov growth mode for initial nucleation in film growth.
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What is laser ablation method for film deposition? Mention the disadvantages.
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With schematic diagram, explain the principal elements and process steps in complex diamond Chemical Vapor Deposition (CVD) method.
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Discuss the constructional details of hot-wall and cold-wall CVD reactors.
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What is sol – gel process method? Discuss the stages of the dip – coating batch process with neat sketch.
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Write notes on the properties and synthesis of Multi-wall carbon nanotube.
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Discuss the principle of synthesis method, structure and uses of Carbon fullerene.
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What is the principle and applications of Atomic layer deposition (ALD) method?
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