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THE REFRACTIVE INDICES OF LIQUID OXYGEN, NITROGEN, AND HYDROGEN |
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Canadian Journal of Research,
Volume 15a,
Issue 7,
1937,
Page 101-108
H. E. Johns,
J. O. Wilhelm,
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摘要:
The refractive indices of liquid oxygen, nitrogen, and hydrogen at temperatures ranging from the normal boiling point to the normal freezing point of the liquefied gases were determined by means of a Wollaston cell for the wavelengths 6939Å, 5461Å, and 4358Å. The values obtained at the normal boiling point for λ = 5461Å were: oxygen, 1.2242; nitrogen, 1.1990; hydrogen, 1.1120.
ISSN:1923-4287
DOI:10.1139/cjr37a-013
出版商:NRC Research Press
年代:1937
数据来源: NRC
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2. |
THE COEFFICIENT OF HEAT TRANSFER FOR VERTICAL SURFACES IN STILL AIR |
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Canadian Journal of Research,
Volume 15a,
Issue 7,
1937,
Page 109-117
R. Ruedy,
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PDF (423KB)
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摘要:
For a vertical plane surface in still air the coefficient of heat transfer, valid within the range of temperatures occurring in buildings, depends on the temperature and the height of the surface. If black body conditions are assumed for the heat lost by radiation, the coefficient is equal to 1.39, 1.50, 1.62, and 1.73 B.t.u. per sq. ft. per ° F. at 32°, 50°, 68°, and 86° F. respectively, the height of the heated surfaces being 100 cm. Convection is responsible for about one-third, and radiation, mainly in the region of 10 microns, for about two-thirds of the heat loss. Convection currents depend on the temperature difference, while radiation depends on the average temperature. When attempts are made to stop convection currents by placing obstacles across the surface, the loss of heat due to natural convection varies inversely as the fourth root of the height, providing that the nature of the flow of air remains unchanged.
ISSN:1923-4287
DOI:10.1139/cjr37a-014
出版商:NRC Research Press
年代:1937
数据来源: NRC
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