5 research outputs found
Theory of the electronic states of semiconductor heterostructures
Get PDFThis thesis is concerned with theoretical calculations of the properties of electronic bound states in semiconductor heterostructures. The complex band structure empirical pseudopotential method (EPM) is used as the foundation of the work. Spin orbit coupling and strain effects (due to lattice mismatch) are included in familiar ways, as is the transfer matrix method, allowing the study of arbitrarily configured heterostructures. These techniques are used to investigate the unusually deep InAs/AlSb conduction band well. The strong possibility of intraband transitions at electro magnetic wavelengths around 1.55µm is predicted, with corresponding enhanced momentum matrix elements and joint density of states over interband transitions. An InAs/GaSb/AlSb asymmetric well is investigated, paying particular attention to the bound states in the vicinity of the InAs/GaSb band overlap. The electron-like states are found to cross with heavy hole and anti-cross with light hole-like states, as a function of heterostructure dimension or applied electrostatic field. This is analogous to the hybridisation of states in the in-plane band structure, except that for zero in-plane wave vector there can be no appreciable hybridisation of electron and heavy hole states. A technique is described that has been developed to extract envelope functions from heterostructure wavefunctions calculated using the realistic complex band structure EPM approach. These envelope functions conform to Burt’s theory (M. G. Burt, J. Phys.: Condens. Matt. 4, 6651 (1992)) in that they are uniquely defined, continuous and smooth over all space. Comparisons with traditional effective mass envelope functions are made. The extracted envelope functions are used to demonstrate conclusively Burt's predictions (M. G. Burt, Superlatt. Mi- crostruct. 17, 335 (1995)) concerning the inadequacy of certain approximations for the calculation of interband dipole matrix elements and charge oscillation. Finally, the issue of k • p operator ordering is convincingly settled, in favour of 'ordered' over 'symmetrised' Hamiltonians, by comparison to EPM calculations, and using EPM derived k • p parameters
The emerging role of Artificial Intelligence (AI) in urban and regional planning in India
No full textUrban and regional planning faces unprecedented challenges in the 21st century, ranging from rapid urbanization and population growth to climate change and resource depletion. In addressing these challenges, artificial intelligence (AI) has emerged as a transformative toolset for planners, offering advanced analytics, predictive modeling, and optimization capabilities. In this paper, the author discusses how artificial intelligence can be integrated into urban and regional planning in India’s socio-economic landscape. It highlights the use of machine learning to predict future trends and interpret complex data sets, geospatial analysis using various AI-powered tools for spatial planning, as well as Natural Language Processing for data mining. As a way of understanding and improving urban infrastructure, deep learning techniques can be used in urban image analysis and agent-based modeling along with urban simulation for better prediction and decision-making. Nevertheless, a great number of actors make it difficult to implement such techniques locally such as the absence of valuable local data, limited infrastructure facilities, professional knowledge gaps among employees and their poor integration into existing planning processes. The article strongly stresses institutional capacity building, interagency cooperation through governance structures and open data initiatives. Importantly, there has been an indication that the Indian government is committed to artificial intelligence based on various initiatives and policies showing its willingness to embrace these technologies despite their minimal
direct application in Indian urban and regional development so far
Restoring Natural Smile With Artificial Eye : A Case Report
Get PDFAims and objectives : fabrication of custom ocular prosthesis for a patient with enucleation defect in one eye. Case description : Impression of the anophthalmic socket was made using irreversible hydrocolloid material using an acrylic resin tray. The impression was poured in two sections. Molten wax was poured into the cast. Try in of the wax pattern was done. Acrylisation was done followed by painting and characterization and after completion of the characterization , a final layer of clear heat cure acrylic is added to the shell and processed by slow curing cycle. After recovering the prosthesis it was polished to get a smooth and shiny surface. CONCLUSION: fabricating a custom ocular prosthesis in this case not only restored the enucleation eye defect but also restored her natural smile
Reduced glutathione and cysteine hydrochloride on crossbred bull semen
Get PDFOver the last few years, good quality freezable semen was not utilized effectively due to less knowledge about the freezability of semen. One reason is the lack of sufficient antioxidants in the seminal plasma and semen extender. The antioxidant content is reduced during the cryopreservation process and causes premature cryo-capacitation and modification of sperm membrane structure upon thawing. So the study of pre-freezing and post thaw seminal parameters like viability, motility, acrosomal integrity, lipid peroxide assay, vanguard distance traveled by sperm, mitochondrial membrane potential, velocity and motility parameters (CASA) and field fertility trial helped to assess the effectiveness of the additives. The conception rate was better in reduced glutathione than the cysteine hydrochloride treated group. The glutathione has improved the poor freezing and maintained the good freezable semen. Thus the field fertility rate was enhanced and in turn helped to prevent waste of good quality germplasm and repeat breeder syndrome in cows
Trees, Shrubs and Grasses for Saltlands: an Annotated Bibliography
Get PDFResource /Energy Economics and Policy,
