The Experts below are selected from a list of 207 Experts worldwide ranked by ideXlab platform
K Park - One of the best experts on this subject based on the ideXlab platform.
-
Nonequilibrium Roughening Transition in a volume conserving system.
Physical review. E Statistical nonlinear and soft matter physics, 2001Co-Authors: K Park, H J Kim, I KimAbstract:We introduce a simple volume conserving stochastic model undergoing a nonequilibrium Roughening Transition (NRT) in 1+1 dimensions. In our model, there is no deposition and evaporation of a particle breaking the volume conserving condition. The degree of roughness of the fluctuating interface in our model is determined by whether or not the hopping of a particle depends on the local slope of the interface. The hopping process of a particle is controlled by the probability 0
-
Nonequilibrium Roughening Transition in a volume conserving system.
Physical Review E, 2001Co-Authors: K Park, H J Kim, In-mook KimAbstract:We introduce a simple volume conserving stochastic model undergoing a nonequilibrium Roughening Transition (NRT) in $1+1$ dimensions. In our model, there is no deposition and evaporation of a particle breaking the volume conserving condition. The degree of roughness of the fluctuating interface in our model is determined by whether or not the hopping of a particle depends on the local slope of the interface. The hopping process of a particle is controlled by the probability $0l~pl~1.$ For $pl1/2,$ a moving particle tends to hop in the downhill direction of the local slope of the interface, and so the interface is in a smooth phase with a zero roughness exponent. For $pg1/2,$ a particle tends to hop in the uphill direction, and so the interface cannot reach a saturated phase. When $p=1/2,$ the hopping of a particle does not depend on the local slope of the interface. Then the interface can reach a saturated phase. The saturated interface at $p=1/2$ is in a rough phase with a nonzero roughness exponent. Our model, therefore, exhibits the NRT at the critical parameter ${p}_{c}=1/2.$
Young Kyu Cho - One of the best experts on this subject based on the ideXlab platform.
-
Roughening Transition of grain boundaries in metals and oxides
Journal of Materials Science, 2005Co-Authors: Duk Yong Yoon, Young Kyu ChoAbstract:Extensive theoretical analysis and experimental observations show surface Roughening Transitions of crystals. The surface Roughening is characterized by step free energy, which gradually decreases to 0 at the Roughening Transition temperature. For a crystal of finite size, the surface Roughening Transition is manifested by gradual increase of the curved edge and corner areas. In alloys, the interfaces between the solid and the liquid phases can be either singular, partially rough, or completely rough at different temperatures. Their thermally induced Roughening Transitions are similar to those of the solid-vapor interfaces. The interface Roughening and the reverse Transition to singular structures can also be induced by additives. The grain boundaries of any misorientation angles in oxides and metals also show Roughening Transitions. The singular grain boundaries have either flat, hill-and-valley, or kinked shapes, and with temperature increase or composition changes, they become defaceted to curved shapes. These defaceted grain boundaries are rough. It is thus possible to produce either singular or rough grain boundaries by heat-treatment or additives to vary their properties.
-
surface Roughening Transition and coarsening of nbc grains in liquid cobalt rich matrix
Journal of the American Ceramic Society, 2004Co-Authors: Young Kyu Cho, Duk Yong Yoon, Byoung-kee KimAbstract:When NbC–30 wt% Co powder compact is sintered at various temperatures where NbC grains (with small amounts of Co) coexist with a liquid Co–NbC matrix, the NbC grains undergo a surface Roughening Transition with temperature increase and the grain growth changes from abnormal to normal growth. When sintered at 1400°C, the grains are polyhedral with sharp edges (and corners) and grow abnormally because their singular surfaces move by nucleation of surface steps. When sintered at 1600°C, the edges become round, indicating the surface Roughening Transition. The grains still grow abnormally, but their number density is larger than that at 1400°C because of the smaller surface step free energy. When sintered at 1820°C, the grains are nearly spherical, but the flat-surface segments still remain. The grain growth at this temperature is nearly normal because of very small surface step free energy. The surface Roughening Transition is reversed when a specimen initially sintered at 1820°C is heat-treated again at 1400°C, but some grains show Transition shapes with nearly flat edges and slope discontinuities (shocks).
-
Grain Boundary Roughening Transition
Materials Science Forum, 2004Co-Authors: Duk Yong Yoon, Young Kyu Cho, Hyun Min JangAbstract:Flat surfaces and grain boundaries lying on low crystal planes are singular corresponding to the cusps in the polar (Wulff) plots of their energy against their orientation. The theoretical analysis of the entropy effect at high temperatures shows that these interfaces undergo Roughening Transitions. The molecular dynamics simulations also show disordering to liquid-like structures at high temperatures that can be interpreted as the Roughening Transition. Experimentally, singular flat surfaces and grain boundaries become curved at high temperatures or with additives, indicating their Roughening Transition. The grain boundaries in polycrystals are often faceted with hill-and-valley shapes and their defaceting at high temperatures also show their Roughening Transition.
-
Surface Roughening Transition and Coarsening of NbC Grains in Liquid Cobalt‐Rich Matrix
Journal of the American Ceramic Society, 2004Co-Authors: Young Kyu Cho, Duk Yong Yoon, Byoung-kee KimAbstract:When NbC–30 wt% Co powder compact is sintered at various temperatures where NbC grains (with small amounts of Co) coexist with a liquid Co–NbC matrix, the NbC grains undergo a surface Roughening Transition with temperature increase and the grain growth changes from abnormal to normal growth. When sintered at 1400°C, the grains are polyhedral with sharp edges (and corners) and grow abnormally because their singular surfaces move by nucleation of surface steps. When sintered at 1600°C, the edges become round, indicating the surface Roughening Transition. The grains still grow abnormally, but their number density is larger than that at 1400°C because of the smaller surface step free energy. When sintered at 1820°C, the grains are nearly spherical, but the flat-surface segments still remain. The grain growth at this temperature is nearly normal because of very small surface step free energy. The surface Roughening Transition is reversed when a specimen initially sintered at 1820°C is heat-treated again at 1400°C, but some grains show Transition shapes with nearly flat edges and slope discontinuities (shocks).
Byoung-kee Kim - One of the best experts on this subject based on the ideXlab platform.
-
surface Roughening Transition and coarsening of nbc grains in liquid cobalt rich matrix
Journal of the American Ceramic Society, 2004Co-Authors: Young Kyu Cho, Duk Yong Yoon, Byoung-kee KimAbstract:When NbC–30 wt% Co powder compact is sintered at various temperatures where NbC grains (with small amounts of Co) coexist with a liquid Co–NbC matrix, the NbC grains undergo a surface Roughening Transition with temperature increase and the grain growth changes from abnormal to normal growth. When sintered at 1400°C, the grains are polyhedral with sharp edges (and corners) and grow abnormally because their singular surfaces move by nucleation of surface steps. When sintered at 1600°C, the edges become round, indicating the surface Roughening Transition. The grains still grow abnormally, but their number density is larger than that at 1400°C because of the smaller surface step free energy. When sintered at 1820°C, the grains are nearly spherical, but the flat-surface segments still remain. The grain growth at this temperature is nearly normal because of very small surface step free energy. The surface Roughening Transition is reversed when a specimen initially sintered at 1820°C is heat-treated again at 1400°C, but some grains show Transition shapes with nearly flat edges and slope discontinuities (shocks).
-
Surface Roughening Transition and Coarsening of NbC Grains in Liquid Cobalt‐Rich Matrix
Journal of the American Ceramic Society, 2004Co-Authors: Young Kyu Cho, Duk Yong Yoon, Byoung-kee KimAbstract:When NbC–30 wt% Co powder compact is sintered at various temperatures where NbC grains (with small amounts of Co) coexist with a liquid Co–NbC matrix, the NbC grains undergo a surface Roughening Transition with temperature increase and the grain growth changes from abnormal to normal growth. When sintered at 1400°C, the grains are polyhedral with sharp edges (and corners) and grow abnormally because their singular surfaces move by nucleation of surface steps. When sintered at 1600°C, the edges become round, indicating the surface Roughening Transition. The grains still grow abnormally, but their number density is larger than that at 1400°C because of the smaller surface step free energy. When sintered at 1820°C, the grains are nearly spherical, but the flat-surface segments still remain. The grain growth at this temperature is nearly normal because of very small surface step free energy. The surface Roughening Transition is reversed when a specimen initially sintered at 1820°C is heat-treated again at 1400°C, but some grains show Transition shapes with nearly flat edges and slope discontinuities (shocks).
I Kim - One of the best experts on this subject based on the ideXlab platform.
-
Nonequilibrium Roughening Transition in a volume conserving system.
Physical review. E Statistical nonlinear and soft matter physics, 2001Co-Authors: K Park, H J Kim, I KimAbstract:We introduce a simple volume conserving stochastic model undergoing a nonequilibrium Roughening Transition (NRT) in 1+1 dimensions. In our model, there is no deposition and evaporation of a particle breaking the volume conserving condition. The degree of roughness of the fluctuating interface in our model is determined by whether or not the hopping of a particle depends on the local slope of the interface. The hopping process of a particle is controlled by the probability 0
H J Kim - One of the best experts on this subject based on the ideXlab platform.
-
Nonequilibrium Roughening Transition in a volume conserving system.
Physical review. E Statistical nonlinear and soft matter physics, 2001Co-Authors: K Park, H J Kim, I KimAbstract:We introduce a simple volume conserving stochastic model undergoing a nonequilibrium Roughening Transition (NRT) in 1+1 dimensions. In our model, there is no deposition and evaporation of a particle breaking the volume conserving condition. The degree of roughness of the fluctuating interface in our model is determined by whether or not the hopping of a particle depends on the local slope of the interface. The hopping process of a particle is controlled by the probability 0
-
Nonequilibrium Roughening Transition in a volume conserving system.
Physical Review E, 2001Co-Authors: K Park, H J Kim, In-mook KimAbstract:We introduce a simple volume conserving stochastic model undergoing a nonequilibrium Roughening Transition (NRT) in $1+1$ dimensions. In our model, there is no deposition and evaporation of a particle breaking the volume conserving condition. The degree of roughness of the fluctuating interface in our model is determined by whether or not the hopping of a particle depends on the local slope of the interface. The hopping process of a particle is controlled by the probability $0l~pl~1.$ For $pl1/2,$ a moving particle tends to hop in the downhill direction of the local slope of the interface, and so the interface is in a smooth phase with a zero roughness exponent. For $pg1/2,$ a particle tends to hop in the uphill direction, and so the interface cannot reach a saturated phase. When $p=1/2,$ the hopping of a particle does not depend on the local slope of the interface. Then the interface can reach a saturated phase. The saturated interface at $p=1/2$ is in a rough phase with a nonzero roughness exponent. Our model, therefore, exhibits the NRT at the critical parameter ${p}_{c}=1/2.$
