Determination of Ionization Rates in the Principal Crystallographic Directions in Silicon.

1983 ◽  
Author(s):  
Charles A. Lee
Keyword(s):  
Ionization Rates

scholarly journals On the Cosmic Ray-Induced Ionization Rate in Molecular Clouds

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Ararat G. Yeghikyan
Keyword(s):  
Molecular Clouds ◽  
Column Density ◽  
Cosmic Ray ◽  
Ionization Rate ◽  
Electronic Interaction ◽  
Absorbing Medium ◽  
Be Star ◽  
Good Agreement ◽  
Ionization Rates

The transformation of the energy dependence of the cosmic ray proton flux in the keV to GeV region is investigated theoretically when penetrating inside molecular clouds ( mag). The computations suggest that energy losses of the cosmic ray particles by interaction with the matter of the molecular cloud are principally caused by the inelastic (electronic) interaction potential; the transformed energy distribution of energetic protons is determined mainly by the column density of the absorbing medium. A cutoff of the cosmic ray spectrum inside clouds by their magnetic fields is also phenomenologically taken into account. This procedure allows a determination of environment-dependent ionization rates of molecular clouds. The theoretically predicted ionization rates are in good agreement with those derived from astronomical observations of absorption lines in the spectrum of the cloud connected with the Herbig Be star LkH 101.

Direct determination of impact-ionization rates near threshold in semiconductors using soft-x-ray photoemission

1992 ◽  
Vol 68 (6) ◽  
pp. 831-834 ◽  
Author(s):  
E. A. Eklund ◽  
P. D. Kirchner ◽  
D. K. Shuh ◽  
F. R. McFeely ◽  
E. Cartier
Keyword(s):  
Impact Ionization ◽  
Direct Determination ◽  
X Ray ◽  
Ionization Rates ◽  
Near Threshold

Reactions of aryl diazonium salts and arylazo alkyl ethers. VI. A comparison of the available methods for the measurement of the rate of ionization of (Z)-arylazo alkyl ethers in alcoholic solvents

1982 ◽  
Vol 35 (2) ◽  
pp. 319 ◽  
Author(s):  
TJ Broxton ◽  
MJ Mcleish
Keyword(s):  
Substituent Effects ◽  
Ionization Rate ◽  
New Method ◽  
Diazonium Salts ◽  
Advantages And Disadvantages ◽  
Diazonium Ions ◽  
Alkyl Ethers ◽  
Trapping Agent ◽  
Ionization Rates

Two previously reported methods for the determination of the ionization rate of (Z)-arylazo alkyl ethers by using x-naphtholate ions as a trapping agent are compared. A new method, which uses thiophenolate ions to trap the free diazonium ions formed in this ionization, is reported. This method is recommended in preference to the earlier methods because it includes a correction for the effect of the ionic strength of the solution on the rate of ionization. Rates measured by the thiophenolate method are consequently lower than those measured by either of the two previous methods. The advantages and disadvantages of the new method are discussed. The magnitude of salt effects and substituent effects on the ionization of (Z)- and (E)-arylazo alkyl ethers are compared.

scholarly journals Determination of interstellar pickup ion distributions in the solar wind with SOHO and Cluster

1996 ◽  
Vol 14 (5) ◽  
pp. 492-496 ◽  
Author(s):  
E. Möbius ◽  
D. Rucinski ◽  
P. A. Isenberg ◽  
M. A. Lee
Keyword(s):  
Interstellar Medium ◽  
Interplanetary Medium ◽  
Direct Detection ◽  
Neutral Density ◽  
Local Interstellar Medium ◽  
Pickup Ions ◽  
Ion Distributions ◽  
Wide Range ◽  
Ionization Rates

Abstract. Over the last 10 years, the experimental basis for the study of the local interstellar medium has been substantially enhanced by the direct detection of interstellar pickup ions and of interstellar neutral helium within the heliosphere. Pickup ions can be studied for a wide range of interstellar species. However, currently the accuracy of the method to determine the parameters of the interstellar medium, namely neutral density, temperature and relative velocity, is hampered by two problems: (1) In most cases the crucial ionization rates are not available from simultaneous measurements and (2) the transport of the pickup ions in the interplanetary medium substantially modifies the measured spatial distribution of the ions. In this study we will discuss how the enhanced capabilities of the instrumentation on SOHO and Cluster in combination with ongoing efforts to model the pickup ion distributions will lead to a significant improvement over the coming years.

Galactic orbits of stars

1966 ◽  
Vol 25 ◽  
pp. 93-97
Author(s):  
Richard Woolley
Keyword(s):  
Globular Cluster ◽  
Potential Field ◽  
High Velocity ◽  
Velocity Vector ◽  
Variable Stars ◽  
The Sun ◽  
Proper Motions ◽  
Rr Lyrae ◽  
The Galaxy

It is now possible to determine proper motions of high-velocity objects in such a way as to obtain with some accuracy the velocity vector relevant to the Sun. If a potential field of the Galaxy is assumed, one can compute an actual orbit. A determination of the velocity of the globular clusterωCentauri has recently been completed at Greenwich, and it is found that the orbit is strongly retrograde in the Galaxy. Similar calculations may be made, though with less certainty, in the case of RR Lyrae variable stars.

Distance to SN 1987A and the LMC

1999 ◽  
Vol 190 ◽  
pp. 549-554
Author(s):  
Nino Panagia
Keyword(s):  
Angular Size ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Light Curves ◽  
Distance Modulus ◽  
Absolute Size ◽  
Sn 1987A

Using the new reductions of the IUE light curves by Sonneborn et al. (1997) and an extensive set of HST images of SN 1987A we have repeated and improved Panagia et al. (1991) analysis to obtain a better determination of the distance to the supernova. In this way we have derived an absolute size of the ringRabs= (6.23 ± 0.08) x 1017cm and an angular sizeR″ = 808 ± 17 mas, which give a distance to the supernovad(SN1987A) = 51.4 ± 1.2 kpc and a distance modulusm–M(SN1987A) = 18.55 ± 0.05. Allowing for a displacement of SN 1987A position relative to the LMC center, the distance to the barycenter of the Large Magellanic Cloud is also estimated to bed(LMC) = 52.0±1.3 kpc, which corresponds to a distance modulus ofm–M(LMC) = 18.58±0.05.

International determination of the total motion of the pole

1961 ◽  
Vol 13 ◽  
pp. 29-41
Author(s):  
Wm. Markowitz
Keyword(s):  
Secular Motion ◽  
The Future

A symposium on the future of the International Latitude Service (I. L. S.) is to be held in Helsinki in July 1960. My report for the symposium consists of two parts. Part I, denoded (Mk I) was published [1] earlier in 1960 under the title “Latitude and Longitude, and the Secular Motion of the Pole”. Part II is the present paper, denoded (Mk II).

Time and Latitude in South Africa

1972 ◽  
Vol 1 ◽  
pp. 27-38
Author(s):  
J. Hers
Keyword(s):  
South Africa ◽  
Cape Town ◽  
Astronomical Observations ◽  
Royal Observatory ◽  
The Republic ◽  
Astronomical Determination ◽  
Limited Accuracy ◽  
Better Than

In South Africa the modern outlook towards time may be said to have started in 1948. Both the two major observatories, The Royal Observatory in Cape Town and the Union Observatory (now known as the Republic Observatory) in Johannesburg had, of course, been involved in the astronomical determination of time almost from their inception, and the Johannesburg Observatory has been responsible for the official time of South Africa since 1908. However the pendulum clocks then in use could not be relied on to provide an accuracy better than about 1/10 second, which was of the same order as that of the astronomical observations. It is doubtful if much use was made of even this limited accuracy outside the two observatories, and although there may – occasionally have been a demand for more accurate time, it was certainly not voiced.

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