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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,135 records · Page 63
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

High-intensity source of extreme ultraviolet

High intensity ultraviolet radiation source was developed which is suitable for emission below 500 A. Source, useful for 100 to 1000 A range, is simple and inexpensive to construct, easy to operate, and very stable. Because of sufficiently intense output spectrum, source can be used with monochromator at wavelengths as low as 160 A.

Paresce, E.↗
NASA NTRS1971

Application of thin films extremely high frequencies

The use of thin film irises to control the beam direction from an array of microwave horns is discussed. The phenomenon is based on the finite transmission of electromagnetic energy through thin films. Diagrams of characteristic waveguides and numerical analyses of the irises are presented.

Ramey, R. L.↗
NASA NTRS1971

Extreme ultraviolet flashes of solar flares observed via sudden frequency deviations - Experimental results.

Properties of solar-flare EUV flashes are described as inferred from ionospheric events called sudden frequency deviation (SFD). SFD's are sensitive to bursts of radiation in the 1-1030 A wavelength range. He II 303.8 A, O V 629.7 A, H L-gamma 972.5 A and C III 977.0 A have essentially the same impulsive time dependence as the 1-1030 A flash responsible for SFD's. Soft X-rays (2-20 A) and certain EUV lines have a much slower time dependence than the 1-1030 A flash. Most SFD's have some fine structure, but marked quasi-periodicity in EUV flashes is quite rare. EUV flashes are closely associated with hard X-ray bursts, white-light emission, microwave radio bursts and small bright impulsive kernels in the H-alpha flare. The intensity of EUV flashes depends on the central meridian distance of the H-alpha flare location; the intensity decreases at the limb.

Donnelly, R. F.↗
NASA NTRS1971

Extreme-ultraviolet observations of a surge.

Observation of a flare surge at the limb in C III 977 A by the Harvard OSO 6 spectroheliometer. The kinematic behavior of the surge is the same in C III and in H alpha. The amount of C III emission is consistent with a model in which the C III ions occupy sheaths with a thickness of about 100 km surrounding the cooler H alpha-emitting threads. The mass of the material containing C III ions is about 0.01 times that emitting H alpha.

Kirshner, R. P.↗
NASA NTRS1972

Extreme-ultraviolet aluminum spectra emitted from a laser-produced plasma.

Five new aluminum lines in the region from 35 to 50 A have been produced by focusing the radiation of a 460-MW, Q-spoiled ruby laser on an aluminum target. Characteristics of the new lines, including their observed and predicted wavelength, intensity, and transition, are tabulated.

Williams, M. D.↗
NASA NTRS1972

Luna 16 sample G36 - Another crystalline product of an extremely mafic magma.

Luna 16 sample G36 is a microbasalt containing skeletal olivine, plagioclase, ilmenite, and interstitial pyroxene. It apparently resulted from very rapid crystallization of a highly fractionated, totally liquid mafic magma. Although different in many details, G36 is generally similar to the ferromagnesian-rich Apollo 11 and 12 basalts. In this respect, it emphasizes the continuing problem of identifying a process on the moon which generated highly mafic magmas.

Hollister, L. S.↗
NASA NTRS1972

Extreme radiation damage in soil from Mare Fecunditatis.

High-voltage electron microscopy has been used to compare radiation effects in micron-size soil grains from the Luna 16 site (Mare Fecunditatis) and the four Apollo landing sites. Radiation damage by heavy solar particles is strikingly greater in the Luna 16 sample than in the other four samples. It is suggested that less movement of the soil at Mare Fecunditatis has taken place, perhaps because of its proximity to the limb and consequent lower exposure to energetic electrons in the earth's magnetospheric tail, which would cause electrostatic agitation of fine particles.

Phakey, P. P.↗
NASA NTRS1972

Threonine deaminase from extremely halophilic bacteria - Cooperative substrate kinetics and salt dependence.

The effect of salt on the activity, stability, and allosteric properties of catabolic threonine deaminase from Halobacterium cutirubrum was studied. The enzyme exhibits sigmoidal kinetics with the substrate, threonine. The Hill slope is 1.55 at pH 10. The enzyme is activated by ADP at low substrate concentrations. In the presence of this effector, sigmoidal kinetics are no longer observed. At pH 10, in the absence of ADP, enzyme activity increases with increasing NaCl concentration from 0 to 4 M.

Lieberman, M. M.↗
NASA NTRS1972

Ogo 4 observations of extremely low frequency hiss.

Analysis of ELF and VLF data from the Stanford University experiment on Ogo 4 revealed an ELF hiss band with characteristics not previously identified. The band, referred to as band-limited ELF hiss, is seen from low to medium latitudes. On the basis of wave-propagation properties, it is proposed that the BLH is generated at large wave normal angles in the equatorial region near L = 4. This model can be used to explain the characteristics of the BLH. Two mechanisms for the generation of BLH based on radiation from energetic electrons are considered.

Muzzio, J. L. R.↗
NASA NTRS1972

The lithium-like spectra of K XVII through Mn XXIII in the extreme-ultraviolet region.

Identifications and classifications of spectral lines in the lithium-like spectra of the elements K through Mn is presented for the first time. The extrapolation procedures used to calculate these spectra are presented in detail. The excellent agreement between the predicted and measured lines establish the long-range extrapolation.

Goldsmith, S.↗