High density expansions in the Thomas‐Fermi approximation

1973 ◽  
Vol 14 (4) ◽  
pp. 537-539 ◽  
Author(s):  
Michael Nauenberg
Keyword(s):  
High Density ◽  
Thomas Fermi ◽  
Density Expansions

High-density expansions of the relativistic Thomas-Fermi equation

1989 ◽  
Vol 40 (5) ◽  
pp. 2731-2737 ◽  
Author(s):  
Y. C. Leung ◽  
Shou-yong Pei
Keyword(s):  
High Density ◽  
Thomas Fermi ◽  
Density Expansions

scholarly journals Addressing the determinants of built-up expansion and densification processes at the regional scale

Urban Studies ◽  
2018 ◽  
Vol 55 (15) ◽  
pp. 3279-3298 ◽  
Author(s):  
Ahmed Mustafa ◽  
Anton Van Rompaey ◽  
Mario Cools ◽  
Ismaïl Saadi ◽  
Jacques Teller
Keyword(s):  
Multinomial Logistic Regression ◽  
Regional Scale ◽  
Controlling Factors ◽  
High Density ◽  
Low Density ◽  
Political Factors ◽  
Infill Development ◽  
Development Policies ◽  
Different Types ◽  
Density Expansions

An in-depth understanding of the main factors behind built-up development is a key prerequisite for designing policies dedicated to a more efficient land use. Infill development policies are essential to curb sprawl and allow a progressive recycling of low-density areas inherited from the past. This paper examines the controlling factors of built-up expansion and densification processes in Wallonia (Belgium). Unlike the usual urban/built-up expansion studies, our approach considers various levels of built-up densities to distinguish between different types of developments, ranging from low-density extensions (or sprawl) to high-density infill development. Belgian cadastral data for 1990, 2000 and 2010 were used to generate four classes of built-up areas, namely, non-, low-, medium- and high-density areas. A number of socioeconomic, geographic and political factors related to built-up development were operationalised following the literature. We then used a multinomial logistic regression model to analyse the effects of these factors on the transitions between different densities in the two decades between 1990 and 2010. The findings indicate that all the controlling factors show distinctive variations based on density. More specifically, the centrality of zoning policies in explaining expansion processes is highlighted. This is especially the case for high-density expansions. In contrast, physical and neighbourhood factors play a larger role in infill development, especially for dense infill development.

Virial and high-density expansions for the Lee-Yang lattice gas

2016 ◽  
Vol 94 (1) ◽  
Author(s):  
M. V. Ushcats ◽  
L. A. Bulavin ◽  
V. M. Sysoev ◽  
S. J. Ushcats
Keyword(s):  
Lattice Gas ◽  
High Density ◽  
Density Expansions

High density expansion for the Thomas-Fermi-Dirac function

1966 ◽  
Vol 292 (1429) ◽  
pp. 288-297 ◽  
Keyword(s):  
Free Electron ◽  
Positive Charge ◽  
Correlation Energy ◽  
Electron Gas ◽  
High Density ◽  
Thomas Fermi ◽  
Dirac Function ◽  
Density Expansion ◽  
Atomic Radii

An expansion is derived for the T.F.D. function at high densities (small atomic radii). Corresponding expansions are derived for the pressure and energy. The latter is compared with the somewhat similar Gell-Mann-Brueckner series for the correlation energy of a free electron gas moving in a background of positive charge.

Planar defects in ordered (Ga,In)P

1988 ◽  
Vol 46 ◽  
pp. 902-903
Author(s):  
S. McKernan ◽  
C. B. Carter ◽  
D. Bour ◽  
J. R. Shealy
Keyword(s):  
Electron Diffraction ◽  
Vapor Phase ◽  
Growth Direction ◽  
High Density ◽  
Ordered Structure ◽  
Planar Defects ◽  
Diffraction Patterns ◽  
Ternary Semiconductors ◽  
Anion Species ◽  
Metallic Vapor

The growth of ternary III-V semiconductors by organo-metallic vapor phase epitaxy (OMVPE) is widely practiced. It has been generally assumed that the resulting structure is the same as that of the corresponding binary semiconductors, but with the two different cation or anion species randomly distributed on their appropriate sublattice sites. Recently several different ternary semiconductors including AlxGa1-xAs, Gaxln-1-xAs and Gaxln1-xP1-6 have been observed in ordered states. A common feature of these ordered compounds is that they contain a relatively high density of defects. This is evident in electron diffraction patterns from these materials where streaks, which are typically parallel to the growth direction, are associated with the extra reflections arising from the ordering. However, where the (Ga,ln)P epilayer is reasonably well ordered the streaking is extremely faint, and the intensity of the ordered spot at 1/2(111) is much greater than that at 1/2(111). In these cases it is possible to image relatively clearly many of the defects found in the ordered structure.

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