The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
Edmund G Seebauer - One of the best experts on this subject based on the ideXlab platform.
-
Temperature dependent energy thresholds for ion stimulated defect formation in Solids effects of ion mass and adsorbate substrate pairing
Surface Science, 2007Co-Authors: Zhengguang Wang, Edmund G SeebauerAbstract:Abstract Recent simulations and experiments have indicated that Solid Temperature affects the dynamics of defect formation when the energies of bombarding ions fall below about 100 eV. The physical picture formulated for this phenomenon predicts that ion mass should exert only a weak influence on the threshold energy for defect formation. The present work experimentally confirms that prediction through mesoscale surface diffusion measurements of Ge on Si(1 1 1) as a marker for ion-induced defect behavior. Furthermore, comparisons between the results and those already obtained for In on Si(1 1 1) and Ge(1 1 1) show that the magnitude of the variation in threshold energy with Temperature (∼0.1 eV/K) is largely independent of the adsorbate–substrate pairing. The present results give further evidence for the existence of a broad class of Temperature-dependent ion-induced defect formation processes.
-
Temperature dependent energy thresholds for ion stimulated defect formation in Solids
Physical Review Letters, 2005Co-Authors: Zhiyue J Wang, Edmund G SeebauerAbstract:Recent simulations and experiments have hinted that the Solid Temperature may affect the dynamics of defect formation when the energies of bombarding ions fall below about 100 eV. The present work offers direct experimental confirmation of this phenomenon through measurements of the energy thresholds for ion-enhanced surface diffusion of indium on silicon and germanium, where transport rates depend upon surface defect formation. Such Temperature-dependent energy thresholds may offer a new means for modulating sputtering and defect formation in a variety of ion processing applications.
Xiaoguang Chen - One of the best experts on this subject based on the ideXlab platform.
-
ultrasonic assisted brazing of al ti dissimilar alloy by a filler metal with a large semi Solid Temperature range
Materials & Design, 2016Co-Authors: Xiaoguang ChenAbstract:Abstract The Solidification Temperature range of filler metal is normally narrow to avoid Solidification cracks. In this paper, a new filler metal was designed that had large Solidification Temperature range between 517.7 and 179.2 °C. The large Solidification Temperature range reduced the residual thermal stress at the braze interface. The shear strength of the Al–Ti dissimilar braze joint increased from 45 MPa to 76 MPa when using the newly developed filler metal (namely ASn-II). The ASn-II filler metal was fabricated by adding 15 wt.% Sn to AlSiZnCuNi filler metal (namely A-I). During cooling, the Al, Si and CuAl2 phases first Solidify from the ASn-II filler metal between 517.7 and 487 °C. During further cooling, residual Sn-rich liquid exists and fills the gaps between the pre-Solidified grains by capillary effects to form a network. The semi-Solid state is maintained in the Temperature range of 487–179.2 °C, during which no residual thermal stress occurs at the braze interface. The softness of the continuous Sn phases could also be beneficial for releasing the residual thermal stress by plastic deformation. Ultrasonic assistance made it possible to conduct the process in air and without using flux. The effect of Sn addition on Ti oxide film removal is also discussed.
Xiaozheng Geng - One of the best experts on this subject based on the ideXlab platform.
-
modeling of particle dispersed melting mechanism and its application in corotating twin screw extrusion
Journal of Polymer Science Part B, 2001Co-Authors: Linjie Zhu, K A Narh, Xiaozheng GengAbstract:Particle-dispersed melting is a complex but important melting mechanism in the corotating twin-screw extruder. In this study, the complex multi-particle-dispersed system was simplified into a single-particle melting model. The finite-difference method was introduced to solve this problem. The simulation results show that the melting of a particle may involve two steps: the heating stage and melting stage. The heating time and melting time depend on Solid concentration, initial melt and Solid Temperature, and shear rate. Calculations indicate that high Solid concentration and Solid Temperature, low melt Temperature and shear rate will result in a more uniform Temperature distribution after polymer melting. The model offers valuable information for designing the melting zone in a corotating twin-screw extruder, especially at high screw speed. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2461–2468, 2001
-
Modeling of particle‐dispersed melting mechanism and its application in corotating twin‐screw extrusion
Journal of Polymer Science Part B: Polymer Physics, 2001Co-Authors: Linjie Zhu, K A Narh, Xiaozheng GengAbstract:Particle-dispersed melting is a complex but important melting mechanism in the corotating twin-screw extruder. In this study, the complex multi-particle-dispersed system was simplified into a single-particle melting model. The finite-difference method was introduced to solve this problem. The simulation results show that the melting of a particle may involve two steps: the heating stage and melting stage. The heating time and melting time depend on Solid concentration, initial melt and Solid Temperature, and shear rate. Calculations indicate that high Solid concentration and Solid Temperature, low melt Temperature and shear rate will result in a more uniform Temperature distribution after polymer melting. The model offers valuable information for designing the melting zone in a corotating twin-screw extruder, especially at high screw speed. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2461–2468, 2001
Zhiyue J Wang - One of the best experts on this subject based on the ideXlab platform.
-
Temperature dependent energy thresholds for ion stimulated defect formation in Solids
Physical Review Letters, 2005Co-Authors: Zhiyue J Wang, Edmund G SeebauerAbstract:Recent simulations and experiments have hinted that the Solid Temperature may affect the dynamics of defect formation when the energies of bombarding ions fall below about 100 eV. The present work offers direct experimental confirmation of this phenomenon through measurements of the energy thresholds for ion-enhanced surface diffusion of indium on silicon and germanium, where transport rates depend upon surface defect formation. Such Temperature-dependent energy thresholds may offer a new means for modulating sputtering and defect formation in a variety of ion processing applications.
Jesus Santamaria - One of the best experts on this subject based on the ideXlab platform.
-
In situ Temperature measurements in microwave-heated gas-Solid catalytic systems. Detection of hot spots and Solid-fluid Temperature gradients in the ethylene epoxidation reaction
Chemical Engineering Journal, 2017Co-Authors: Adrian Ramirez, Jose L. Hueso, Reyes Mallada, Jesus SantamariaAbstract:Abstract Infrared thermographic techniques have been used for the first time to determine real-time gas and Solid Temperatures, as well as gas-Solid Temperature gradients in microwave heated structured reactors. A special reactor vessel has been developed that allows direct observation of the catalyst under microwave heating, and an operating procedure is presented to obtain gas and Solid apparent emissivities as a function of Temperature. These values are thereafter used to calculate Temperatures at any point in the gas and Solid phases under reaction. The method has been used to obtain gas and Solid Temperatures during the ethylene epoxidation reaction carried out on a silver-copper oxide catalyst. The direct heating of the monolith walls produced a stable, large Temperature gradient between the Solid and the gas phase.