Results 171 to 180 of about 2,441 (222)

Thermionic emission properties of hexaborides

Surface Science Letters, 1980
Abstract Thermionic emission properties of the single crystal hexaborides LaB6, CeB6, PrB6, NdB6, SmB6, EuB6, (La, Sr)B6, (La, Ba)B6, (La, Ce)B6, (La, Pr)B6, (La, Sm)B6, and (La, Dy)B6 are measured in the temperature range between 1250 and 1700°C.
M. Futamoto, M. Nakazawa, U. Kawabe
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Equations for Thermionic Emission

Nature, 1926
IN 1923, S. Dushman developed a general equation for thermionic emission, in agreement with the hitherto less frequently used one of the two equations suggested by O. W. Richardson, namely, when i = thermionic current in amp./cm.2. T = absolute temperature. b = constant for the substance. A = a universal constant.
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Thermionic Electron Emission*

Bell System Technical Journal, 1935
There have appeared in the Reviews of Modem Physics two excellent summaries on thermionic emission, one by Compton and Langmuir1 and one by Dushman.2 Compton and Lan gmuir, while dealing primarily with discharge in gases, also discussed many phases of thermionic emission. Dushman's article is a comprehensive review on thermionics.
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Thermionic Emission Constants and Band Overlap

Proceedings of the Physical Society, 1948
A general treatment is given of the effect of band overlap on thermionic emission. The results are applied to nickel, for which the experimental value of the current constant A of 1380 amp. cm-2 deg-2 differs markedly from the standard value of 120 amp. cm-2 deg-2.
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THERMIONIC EMISSION FROM FULLERENES

International Journal of Modern Physics B, 1992
Fullerenes in the gas phase, excited by a pulsed laser, exhibit thermionic emission. We analyze the time dependence of the ion yield of C n + in a mass spectrometer. By pulsing the extraction field of the ion lens, we are able to observe delayed ions formed as late as 50 µs after excitation by the 2nd, 3rd or 4th harmonic of a Q-switched YAG laser ...
Walder, Gerhard, Echt, Olof
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Thermionic emission from the fullerenes

Zeitschrift für Physik D Atoms, Molecules and Clusters, 1992
Delayed ionisation of the fullerenes is reported over a timescale of up to 16 µs and compared to the Klots' model for thermionic emission [1]. The laser fluence dependence of the observed time constants for ionisation and the measured dependence on cluster size are in good agreement with model predictions giving strong evidence for the thermionic ...
E. E. B. Campbell, G. Ulmer, I. V. Hertel   +2 more
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Automatic Regulation of Thermionic Emission

Journal of Scientific Instruments, 1950
A circuit is described which automatically controls the emission of thermionic devices for large changes of emission characteristics, and is also independent of large mains voltage fluctuations. In this circuit the power required to heat the emissive surface is controlled by two valves which have the two primary windings of the filament transformer as ...
W Steckelmacher, S van der Meer
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Thermionic emission from fullerenes

Zeitschrift für Physik D Atoms, Molecules and Clusters, 1993
We investigate the time dependence of carbon cluster ions, formed via thermionic emission from photoexcited fullerenes (C60 and C70). By pulsing the extraction field, we are able to observe delayed ions formed as late as 100 µs after excitation at 532 nm, 355 nm, or 266 nm. All even-sized clusters in the range 36 ≤ n ≤ 70 undergo thermionic emission.
Walder, Gerhard, Kennedy, Keith W., Echt, Olof   +2 more
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Thermionic Emission of Thoriated Tungsten

The Journal of Chemical Physics, 1958
Methods were developed for quantitative chemical analysis of those constituents of thoriated tungsten filaments, both uncarbonized and carbonized, which are significant for thermionic emission. Sensitivity was adequate for analysis of an individual filament; therefore the composition of each filament could be correlated with both its thermionic ...
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Thermionic emission from carbon

Proceedings of the Physical Society, 1938
Observations of the thermionic emission from a carefully outgassed filament of graphitic carbon were made at a series of temperatures between 1665° and 2191° K. The corresponding values of the constants A and ψ in the empirical emission formula i = AT2exp(-ψ/kT) were found to be 30 amp./cm.2-deg.2 and 4.34 eV. respectively.
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