The Experts below are selected from a list of 36996 Experts worldwide ranked by ideXlab platform
Rogério Martins Saldanha Da Gama - One of the best experts on this subject based on the ideXlab platform.
-
On the conduction/radiation Heat Transfer Problem in a body with wavelength-dependent properties
Applied Mathematical Modelling, 2004Co-Authors: Rogério Martins Saldanha Da GamaAbstract:Abstract In this work the coupled conduction/radiation Heat Transfer phenomenon in an opaque convex body with radiation properties depending on the wavelength is mathematically modelled. The considered Heat Transfer process is described by a partial differential equation subjected to a nonlinear boundary condition which involves the classical Planck's law. In order to provide a more adequate description, a modified version of Planck's law is constructed and a minimum principle is employed for proving existence and uniqueness of the solution, and which provides a way for simulating the considered nonlinear energy Transfer phenomenon.
-
The nonlinear conduction/radiation Heat Transfer phenomenon represented as the limit of a sequence of linear Problems
International Communications in Heat and Mass Transfer, 1998Co-Authors: Rogério Martins Saldanha Da GamaAbstract:Abstract In this work it is presented a procedure for constructing the solution of conduction/radiation Heat Transfer Problems (inherently nonlinear) from a sequence of linear Problems. It is shown that the solutions of these linear Problems give rise to a nondecreasing sequence (always convergent) whose limit is exactly the solution of the original nonlinear conduction/radiation Heat Transfer Problem. In addition it is presented a way for estimating the error at each iteration. A particular example is considered to illustrate the procedure.
-
the nonlinear conduction radiation Heat Transfer phenomenon represented as the limit of a sequence of linear Problems
International Communications in Heat and Mass Transfer, 1997Co-Authors: Rogério Martins Saldanha Da GamaAbstract:Abstract In this work it is presented a procedure for constructing the solution of conduction/radiation Heat Transfer Problems (inherently nonlinear) from a sequence of linear Problems. It is shown that the solutions of these linear Problems give rise to a nondecreasing sequence (always convergent) whose limit is exactly the solution of the original nonlinear conduction/radiation Heat Transfer Problem. In addition it is presented a way for estimating the error at each iteration. A particular example is considered to illustrate the procedure.
Julia Eizenkop - One of the best experts on this subject based on the ideXlab platform.
-
single pulse excimer laser nanostructuring of silicon a Heat Transfer Problem and surface morphology
Journal of Applied Physics, 2008Co-Authors: Julia Eizenkop, Ivan Avrutsky, Daniel G Georgiev, Vipin ChaudcharyAbstract:We present computer modeling along with experimental data on the formation of sharp conical tips on silicon-based three-layer structures that consist of a single-crystal Si layer on a 1 μm layer of silica on a bulk Si substrate. The upper Si layers with thicknesses in the range of 0.8−4.1 μm were irradiated by single pulses from a KrF excimer laser focused onto a spot several micrometers in diameter. The computer simulation includes two-dimensional time-dependent Heat Transfer and phase transformations in Si films that result from the laser irradiation (the Stefan Problem). After the laser pulse, the molten material self-cools and resolidifies, forming a sharp conical structure, the height of which can exceed 1 μm depending on the irradiation conditions. We also performed computer simulations for experiments involving single-pulse irradiation of bulk silicon, reported by other groups. We discuss conditions under which different types of structures (cones versus hollows) emerge. We confirm a correlation be...
-
single pulse excimer laser nanostructuring of thin silicon films nanosharp cones formation and a Heat Transfer Problem
Journal of Applied Physics, 2007Co-Authors: Julia Eizenkop, Ivan Avrutsky, Daniel G Georgiev, Gregory W Auner, Vipin ChaudharyAbstract:We present analytical and computer modeling along with an experiment on the formation of sharp conical tips on monocrystalline silicon thin films, silicon-on-insulator, subjected to irradiation by single 25 ns pulses from a KrF excimer laser focused into a spot several micrometers in diameter. These fabricated structures have heights of about 1 μm and apical radii of curvature of several tens of nanometers. We offer a simplified analytical model for the formation of these structures. The computer simulation includes two-dimensional time-dependant Heat Transfer and phase transformations in Si films on SiO2 substrates that result from the laser irradiation (the Stefan Problem). It is shown that upon irradiation and initial melting, the liquid/solid interface remains mainly parallel to the surface of the film. After the laser pulse, the molten material self-cools and resolidifies. The solid/liquid interface moves predominately laterally toward the center of the irradiated spot, forming an almost vertical fro...
Vipin Chaudchary - One of the best experts on this subject based on the ideXlab platform.
-
single pulse excimer laser nanostructuring of silicon a Heat Transfer Problem and surface morphology
Journal of Applied Physics, 2008Co-Authors: Julia Eizenkop, Ivan Avrutsky, Daniel G Georgiev, Vipin ChaudcharyAbstract:We present computer modeling along with experimental data on the formation of sharp conical tips on silicon-based three-layer structures that consist of a single-crystal Si layer on a 1 μm layer of silica on a bulk Si substrate. The upper Si layers with thicknesses in the range of 0.8−4.1 μm were irradiated by single pulses from a KrF excimer laser focused onto a spot several micrometers in diameter. The computer simulation includes two-dimensional time-dependent Heat Transfer and phase transformations in Si films that result from the laser irradiation (the Stefan Problem). After the laser pulse, the molten material self-cools and resolidifies, forming a sharp conical structure, the height of which can exceed 1 μm depending on the irradiation conditions. We also performed computer simulations for experiments involving single-pulse irradiation of bulk silicon, reported by other groups. We discuss conditions under which different types of structures (cones versus hollows) emerge. We confirm a correlation be...
Daniel G Georgiev - One of the best experts on this subject based on the ideXlab platform.
-
single pulse excimer laser nanostructuring of silicon a Heat Transfer Problem and surface morphology
Journal of Applied Physics, 2008Co-Authors: Julia Eizenkop, Ivan Avrutsky, Daniel G Georgiev, Vipin ChaudcharyAbstract:We present computer modeling along with experimental data on the formation of sharp conical tips on silicon-based three-layer structures that consist of a single-crystal Si layer on a 1 μm layer of silica on a bulk Si substrate. The upper Si layers with thicknesses in the range of 0.8−4.1 μm were irradiated by single pulses from a KrF excimer laser focused onto a spot several micrometers in diameter. The computer simulation includes two-dimensional time-dependent Heat Transfer and phase transformations in Si films that result from the laser irradiation (the Stefan Problem). After the laser pulse, the molten material self-cools and resolidifies, forming a sharp conical structure, the height of which can exceed 1 μm depending on the irradiation conditions. We also performed computer simulations for experiments involving single-pulse irradiation of bulk silicon, reported by other groups. We discuss conditions under which different types of structures (cones versus hollows) emerge. We confirm a correlation be...
-
single pulse excimer laser nanostructuring of thin silicon films nanosharp cones formation and a Heat Transfer Problem
Journal of Applied Physics, 2007Co-Authors: Julia Eizenkop, Ivan Avrutsky, Daniel G Georgiev, Gregory W Auner, Vipin ChaudharyAbstract:We present analytical and computer modeling along with an experiment on the formation of sharp conical tips on monocrystalline silicon thin films, silicon-on-insulator, subjected to irradiation by single 25 ns pulses from a KrF excimer laser focused into a spot several micrometers in diameter. These fabricated structures have heights of about 1 μm and apical radii of curvature of several tens of nanometers. We offer a simplified analytical model for the formation of these structures. The computer simulation includes two-dimensional time-dependant Heat Transfer and phase transformations in Si films on SiO2 substrates that result from the laser irradiation (the Stefan Problem). It is shown that upon irradiation and initial melting, the liquid/solid interface remains mainly parallel to the surface of the film. After the laser pulse, the molten material self-cools and resolidifies. The solid/liquid interface moves predominately laterally toward the center of the irradiated spot, forming an almost vertical fro...
Ivan Avrutsky - One of the best experts on this subject based on the ideXlab platform.
-
single pulse excimer laser nanostructuring of silicon a Heat Transfer Problem and surface morphology
Journal of Applied Physics, 2008Co-Authors: Julia Eizenkop, Ivan Avrutsky, Daniel G Georgiev, Vipin ChaudcharyAbstract:We present computer modeling along with experimental data on the formation of sharp conical tips on silicon-based three-layer structures that consist of a single-crystal Si layer on a 1 μm layer of silica on a bulk Si substrate. The upper Si layers with thicknesses in the range of 0.8−4.1 μm were irradiated by single pulses from a KrF excimer laser focused onto a spot several micrometers in diameter. The computer simulation includes two-dimensional time-dependent Heat Transfer and phase transformations in Si films that result from the laser irradiation (the Stefan Problem). After the laser pulse, the molten material self-cools and resolidifies, forming a sharp conical structure, the height of which can exceed 1 μm depending on the irradiation conditions. We also performed computer simulations for experiments involving single-pulse irradiation of bulk silicon, reported by other groups. We discuss conditions under which different types of structures (cones versus hollows) emerge. We confirm a correlation be...
-
single pulse excimer laser nanostructuring of thin silicon films nanosharp cones formation and a Heat Transfer Problem
Journal of Applied Physics, 2007Co-Authors: Julia Eizenkop, Ivan Avrutsky, Daniel G Georgiev, Gregory W Auner, Vipin ChaudharyAbstract:We present analytical and computer modeling along with an experiment on the formation of sharp conical tips on monocrystalline silicon thin films, silicon-on-insulator, subjected to irradiation by single 25 ns pulses from a KrF excimer laser focused into a spot several micrometers in diameter. These fabricated structures have heights of about 1 μm and apical radii of curvature of several tens of nanometers. We offer a simplified analytical model for the formation of these structures. The computer simulation includes two-dimensional time-dependant Heat Transfer and phase transformations in Si films on SiO2 substrates that result from the laser irradiation (the Stefan Problem). It is shown that upon irradiation and initial melting, the liquid/solid interface remains mainly parallel to the surface of the film. After the laser pulse, the molten material self-cools and resolidifies. The solid/liquid interface moves predominately laterally toward the center of the irradiated spot, forming an almost vertical fro...