scholarly journals Forcing and response in simulated 20th and 21st century surface energy and precipitation trends

2009 ◽  
Vol 114 (D17) ◽  
Author(s):  
Timothy Andrews
Keyword(s):  
Surface Energy ◽  
21St Century ◽  
Precipitation Trends

Studies of 21st-century precipitation trends over West Africa

2010 ◽  
Vol 31 (10) ◽  
pp. 1415-1424 ◽  
Author(s):  
Leonard M. Druyan
Keyword(s):  
West Africa ◽  
21St Century ◽  
Precipitation Trends

Surface energy budget changes over Central Australia during the early 21st century drought

2016 ◽  
Vol 37 (1) ◽  
pp. 159-168 ◽  
Author(s):  
Norman G. Loeb ◽  
Hailan Wang ◽  
Lusheng Liang ◽  
Seiji Kato ◽  
Fred G. Rose
Keyword(s):  
Surface Energy ◽  
21St Century ◽  
Energy Budget ◽  
Surface Energy Budget ◽  
Early 21St Century ◽  
Central Australia ◽  
The Early 21St Century

The annealed (0001) α-alumina surface and its influence on thin-film growth

1995 ◽  
Vol 53 ◽  
pp. 336-337
Author(s):  
Michael W. Bench ◽  
Paul G. Kotula ◽  
C. Barry Carter
Keyword(s):  
Electron Microscopy ◽  
Surface Energy ◽  
Film Growth ◽  
Thin Film Growth ◽  
Energy Calculations ◽  
Transmission Electron ◽  
Reflection Electron Microscopy ◽  
Low Energy Electron ◽  
Surface Nature

The growth of semiconductors, superconductors, metals, and other insulators has been investigated using alumina substrates in a variety of orientations. The surface state of the alumina (for example surface reconstruction and step nature) can be expected to affect the growth nature and quality of the epilayers. As such, the surface nature has been studied using a number of techniques including low energy electron diffraction (LEED), reflection electron microscopy (REM), transmission electron microscopy (TEM), molecular dynamics computer simulations, and also by theoretical surface energy calculations. In the (0001) orientation, the bulk alumina lattice can be thought of as a layered structure with A1-A1-O stacking. This gives three possible terminations of the bulk alumina lattice, with theoretical surface energy calculations suggesting that termination should occur between the Al layers. Thus, the lattice often has been described as being made up of layers of (Al-O-Al) unit stacking sequences. There is a 180° rotation in the surface symmetry of successive layers and a total of six layers are required to form the alumina unit cell.

The nucleation of cavities at grain boundaries

1987 ◽  
Vol 45 ◽  
pp. 288-291
Author(s):  
P. J. Goodhew
Keyword(s):  
Surface Tension ◽  
Surface Energy ◽  
Grain Boundaries ◽  
Radiation Damage ◽  
Impurity Concentration ◽  
Driving Force ◽  
Nucleation And Growth ◽  
Phase Boundaries ◽  
Cavity Nucleation ◽  
Spherical Bubble

Cavity nucleation and growth at grain and phase boundaries is of concern because it can lead to failure during creep and can lead to embrittlement as a result of radiation damage. Two major types of cavity are usually distinguished: The term bubble is applied to a cavity which contains gas at a pressure which is at least sufficient to support the surface tension (2g/r for a spherical bubble of radius r and surface energy g). The term void is generally applied to any cavity which contains less gas than this, but is not necessarily empty of gas. A void would therefore tend to shrink in the absence of any imposed driving force for growth, whereas a bubble would be stable or would tend to grow. It is widely considered that cavity nucleation always requires the presence of one or more gas atoms. However since it is extremely difficult to prepare experimental materials with a gas impurity concentration lower than their eventual cavity concentration there is little to be gained by debating this point.

E-Learning: Educating the 21st Century Speech-Language Pathologist

ASHA Leader ◽  
2007 ◽  
Vol 12 (14) ◽  
pp. 24-25 ◽  
Author(s):  
Gloria D. Kellum ◽  
Sue T. Hale
Keyword(s):  
21St Century ◽  
Speech Language Pathologist ◽  
E Learning
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