On the Stability of Ionization Fronts. II

1966 ◽  
Vol 145 ◽  
pp. 116 ◽  
Author(s):  
Allan F. Saaf
Keyword(s):  
Ionization Fronts ◽  
The Stability

On the Stability of Ionization Fronts.

1962 ◽  
Vol 135 ◽  
pp. 212 ◽  
Author(s):  
Peter O. Vandervoort
Keyword(s):  
Ionization Fronts ◽  
The Stability

The Stability of Ionization Fronts

1967 ◽  
Vol 149 ◽  
pp. 571 ◽  
Author(s):  
R. C. Newman ◽  
W. I. Axford
Keyword(s):  
Ionization Fronts ◽  
The Stability

scholarly journals On the Stability of Ionization Fronts

1958 ◽  
Vol 8 ◽  
pp. 1058-1061
Author(s):  
F. D. Kahn
Keyword(s):  
Interstellar Gas ◽  
Hii Region ◽  
Characteristic Shape ◽  
Ionization Fronts ◽  
Dark Material ◽  
The Stability

The boundaries between HII and HI regions often have shapes which suggest that the motion of the interstellar gas is unstable there. A characteristic shape of this kind is the so-called “elephant's trunk,” a long tongue of dark material (presumably an HI region) seen superimposed on the luminous HII region, and outlined by a thin rim brighter than the luminous background. A detailed study of these shapes has recently been made by Pottasch; earlier observations had been made by Duncan and by Struve.

The Stability of Ionization Fronts.

1964 ◽  
Vol 69 ◽  
pp. 133
Author(s):  
W. I. Axford
Keyword(s):  
Ionization Fronts ◽  
The Stability

The Stability of Ionization Fronts.

1964 ◽  
Vol 140 ◽  
pp. 112 ◽  
Author(s):  
W. I. Axford
Keyword(s):  
Ionization Fronts ◽  
The Stability

On the Stability of Ionization Fronts

1958 ◽  
Vol 30 (3) ◽  
pp. 1058-1061 ◽  
Author(s):  
F. D. Kahn
Keyword(s):  
Ionization Fronts ◽  
The Stability

Open discussion

1982 ◽  
Vol 99 ◽  
pp. 605-613
Author(s):  
P. S. Conti
Keyword(s):  
Buenos Aires ◽  
Large Mass ◽  
List Type ◽  
Common Phenomenon ◽  
Open Discussion ◽  
The Stability ◽  
Ring Nebulae

Conti: One of the main conclusions of the Wolf-Rayet symposium in Buenos Aires was that Wolf-Rayet stars are evolutionary products of massive objects. Some questions:–Do hot helium-rich stars, that are not Wolf-Rayet stars, exist?–What about the stability of helium rich stars of large mass? We know a helium rich star of ∼40 MO. Has the stability something to do with the wind?–Ring nebulae and bubbles : this seems to be a much more common phenomenon than we thought of some years age.–What is the origin of the subtypes? This is important to find a possible matching of scenarios to subtypes.

Symmetric Multistep Methods Revisited: II. Numerical Experiments

1999 ◽  
Vol 173 ◽  
pp. 309-314 ◽  
Author(s):  
T. Fukushima
Keyword(s):  
Multistep Methods ◽  
Computational Time ◽  
Integration Time ◽  
Implicit Methods ◽  
Symmetric Methods ◽  
Celestial Bodies ◽  
The Stability ◽  
Predictor Corrector ◽  
Symmetric Multistep Methods ◽  
Integration Errors

AbstractBy using the stability condition and general formulas developed by Fukushima (1998 = Paper I) we discovered that, just as in the case of the explicit symmetric multistep methods (Quinlan and Tremaine, 1990), when integrating orbital motions of celestial bodies, the implicit symmetric multistep methods used in the predictor-corrector manner lead to integration errors in position which grow linearly with the integration time if the stepsizes adopted are sufficiently small and if the number of corrections is sufficiently large, say two or three. We confirmed also that the symmetric methods (explicit or implicit) would produce the stepsize-dependent instabilities/resonances, which was discovered by A. Toomre in 1991 and confirmed by G.D. Quinlan for some high order explicit methods. Although the implicit methods require twice or more computational time for the same stepsize than the explicit symmetric ones do, they seem to be preferable since they reduce these undesirable features significantly.

Uniformity of Magnification from Different Electron Microscopes

1967 ◽  
Vol 25 ◽  
pp. 32-33
Author(s):  
Godfrey C. Hoskins ◽  
V. Williams ◽  
V. Allison
Keyword(s):  
Diffraction Grating ◽  
The Other ◽  
Carbon Replica ◽  
Electron Microscopes ◽  
The Stability

The method demonstrated is an adaptation of a proven procedure for accurately determining the magnification of light photomicrographs. Because of the stability of modern electrical lenses, the method is shown to be directly applicable for providing precise reproducibility of magnification in various models of electron microscopes.A readily recognizable area of a carbon replica of a crossed-line diffraction grating is used as a standard. The same area of the standard was photographed in Phillips EM 200, Hitachi HU-11B2, and RCA EMU 3F electron microscopes at taps representative of the range of magnification of each. Negatives from one microscope were selected as guides and printed at convenient magnifications; then negatives from each of the other microscopes were projected to register with these prints. By deferring measurement to the print rather than comparing negatives, correspondence of magnification of the specimen in the three microscopes could be brought to within 2%.

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