共查询到20条相似文献，搜索用时 78 毫秒
1.
Comstock GM Fleischer RL Giard WR Hart HR Nichols GE Price PB 《Science (New York, N.Y.)》1971,172(3979):154-157
Counts of tracks from heavy cosmic-ray nuclei in helmets from Apollo missions 8 and 12 show variations caused by solar modulation of the galactic cosmic-ray flux. Specific estimates of the biological damage to certain nonreplaceable cells by track-forming particles during these space missions indicate that the fraction of deactivated cells could range from a lower limit of 3 x 10(-7) to an upper limit of 1.4 x 10(-4). 相似文献
2.
Fleischer RL Haines EL Hanneman RE Hart HR Kasper JS Lifshin E Woods RT Price PB 《Science (New York, N.Y.)》1970,167(3918):568-571
Particle tracks in Apollo 11 samples are dominantly of cosmic ray and solar origin: primary galactic and solar flare particles, likely spallation recoil tracks, and possible solar-wind heavy particles. The energy spectrum of irongroup nuclei is inferred from track density gradients in surface layers, and a limit of < 10(-7) centimeter per year is deduced for the surface erosion rate. From cosmic ray tracks in rock and core samples it is clear that the lunar soil is stirred often during each few million years. X-rays reveal augite, anorthite, olivine, ilmenite, troilite, nonmeteoritic iron, and assorted glasses, but no major structural damage. Hydrogen, helium, and other gases in the fines are compatible with expected solar wind ratios. 相似文献
3.
Fleischer RL Hart HR Comstock GM Carter M Renshaw A Hardy A 《Science (New York, N.Y.)》1973,181(4098):436-438
Doses of heavy particles at positions inside the command modules of Apollo missions 8, 12, 14, and 16 correlate well with the calculated effects of solar modulation of the primary cosmic radiation. Differences in doses at different stowage positions indicate that the redistribution of mass within the spacecraft could enhance safety from the biological damage that would otherwise be expected on manned, deep-space missions. 相似文献
4.
Adler I Trombka J Gerard J Lowman P Schmadebeck R Blodget H Eller E Yin L Lamothe R Osswald G Gorenstein P Bjorkholm P Gursky H Harris B 《Science (New York, N.Y.)》1972,177(4045):256-259
The lunar surface was mapped with respect to magnesium, aluminum, and silicon as aluminum/ silicon and magnesium/ silicon intensity ratios along the projected ground tracks swept out by the orbiting Apollo 16 spacecraft. The results confirm the observations made during the Apollo 15 flight and provide new data for a number of features not covered before. The data are consistent with the idea that the moon has a widespread differentiated crust (the highlands). The aluminum/ silicon and magnesium/ silicon concentration ratios correspond to those for anorthositic gabbros through gabbroic anorthosites or feldspathic basalts. The x-ray results suggest the occurrence of this premare crust or material similar to it at the Descartes landing site. 相似文献
5.
Beaujean R Schmidt M Enge W Siegmon G Krause J Fischer E 《Science (New York, N.Y.)》1984,225(4658):193-195
A stack of plastic nuclear track detectors was exposed to heavy cosmic rays on the pallet of Spacelab 1. Some layers of the stack were rotated with respect to the main stack to determine the arrival time of the particles. After return of the stack the latent particle tracks are revealed by chemical etching. Under the optical microscope the charge, mass, energy, and impact direction of the particles can be deduced from the track geometry. 相似文献
6.
A one-step, three-component aqueous etchant was developed for revealing the tracks of charged particles in olivine. The etchant reveals tracks of small cone angle, which are equally well developed in all the crystallographic directions. The scope of fossil cosmic-ray track studies in extraterrestrial samples has thus been increased, because olivine is often an abundant constituent and because it has a higher threshold ionization for track registration and has lower uranium, thorium, and trace element concentrations as compared with pyroxenes and feldspars. The etchant does not attack any of the principal rock-forming minerals in normal etching time, which allows a nondestructive study of fossil tracks in thin-section mounts. The study of fossil cosmic-ray tracks in olivine is particularly valuable for investigations of very, very heavy cosmic-ray nuclei and for highly irradiated samples such as those found in the lunar regolith. 相似文献
7.
The energetic nuclei in cosmic rays interact with meteoroids, the moon, planets, and other solar system matter. The nuclides and heavy nuclei tracks produced by the cosmic-ray particles in these targets contain a wealth of information about the history of the objects and temporal and spatial variations in the particle fluxes. Most lunar samples and meny meteorites have complex histories of cosmicray exposure from erosion, gardening, fragmentation, orbital changes, and other processes. There appear to be variations in the past fluxes of solar particles, and possibly also galactic cosmic rays, on time scales of 10(4) to 10(7) years. 相似文献
8.
A glass filter from Surveyor 3 has a surface density of approximately 1 x 10(6) tracks per square centimeter from heavy solar flare particles. The variation with depth is best fitted with a solar particle spectrum dN/dE = 2.42 x 10(6) E(-2) [in particles per square centimeter per year per steradian per (million electron volts per nucleon)], where E is the energy and N is the number of particles, from 2 million electron volts per nucleon to approximately 7 million electron volts per nucleon and dN/dE = 1.17 x 10(7) E(-3) at higher energies. Not much difference is observed between 0.5 and 5 micrometers, an indication that there is a lack of track-registering particles below 0.5 million electron volts per nucleon. The Surveyor data are compatible with track results in lunar rocks, provided an erosion rate of approximately 10(-7) centimeter per year is assumed for the latter. The results also suggest a small-scale erosion process in lunar rocks. 相似文献
9.
Jaffe LD 《Science (New York, N.Y.)》1971,171(3973):798-799
Analysis of discoloration patterns on the camera of the spacecraft Surveyor 3, after the Apollo 12 lunar module landed nearby, indicates that lunar surface particles were eroded and entrained by lunar modute exhaust during the landing and were ejected almost horizontally at 70 meters per second or faster. These particles struck the Surveyor camere and whitenzed its surface. 相似文献
10.
11.
Comparison of values of the specific radioactivities reported for lunar surface material from the Apollo 11 mission with analogous data for stone meteorites suggests that energetic particles from the solar flare of 12 April 1969 may have produced most of the cobalt-56 observed. 相似文献
12.
Under certain conditions ships can affect the structure of shallow layer clouds. Simultaneous observations of two ship track signatures in stratus clouds from a satellite and in situ from an aircraft show that in the ship tracks the droplet sizes were reduced and total concentrations of both droplets and particles were substantially increased from those in adjacent clouds. In situ measurements of the upwelling radiance within the ship tracks was significantly enhanced at visible wavelengths, whereas radiance at 2.2 micrometers was significantly reduced. Cloud reflectivity along the tracks was enhanced at 0.63 and 3.7 micrometers. These observations support the contention that ship track signatures in clouds are produced primarily by particles emitted from ships. 相似文献
13.
Fuchs LH 《Science (New York, N.Y.)》1970,169(3948):866-868
Rock fragments consisting of orthopyroxene-calcic plagioclase assemblages appear to be more common in Apollo 12 soil samples than in the breccias or soil from Apollo 11 and are mineralogically and chemically different from any of the crystalline rocks returned by either Apollo 11 or Apollo 12. Compositionally, these fragments are orthopyroxenites and feldspathic orthopyroxenites. They are probably not fragments of meteorites; other considerations point to a near-surface lunar origin. 相似文献
14.
Lunar sample Preliminary Examination Team 《Science (New York, N.Y.)》1971,173(3998):681-693
The major findings of the preliminary examination of the lunar samples are as follows: 1) The samples from Fra Mauro base may be contrasted with those from Tranquillity base and the Ocean of Storms in that about half the Apollo 11 samples consist of basaltic rocks, and all but three Apollo 12 rocks are basaltic, whereas in the Apollo 14 samples only two rocks of the 33 rocks over 50 grams have basaltic textures. The samples from Fra Mauro base consist largely of fragmental rocks containing clasts of diverse lithologies and histories. Generally the rocks differ modally from earlier lunar samples in that they contain more plagioclase and contain orthopyroxene. 2) The Apollo 14 samples differ chemically from earlier lunar rocks and from their closest meteorite and terrestrial analogs. The lunar material closest in composition is the KREEP component (potassium, rare earth elements, phosphorus), "norite," "mottled gray fragments" (9) from the soil samples (in particular, sample 12033) from the Apollo 12 site, and the dark portion of rock 12013 (10). The Apollo 14 material is richer in titanium, iron, magnesium, and silicon than the Surveyor 7 material, the only lunar highlands material directly analyzed (11). The rocks also differ from the mare basalts, having much lower contents of iron, titanium, manganese, chromium, and scandium and higher contents of silicon, aluminum, zirconium, potassium, uranium, thorium, barium, rubidium, sodium, niobium, lithium, and lanthanum. The ratios of potassium to uranium are lower than those of terrestrial rocks and similar to those of earlier lunar samples. 3) The chemical composition of the soil closely resembles that of the fragmental rocks and the large basaltic rock (sample 14310) except that some elements (potassium, lanthanum, ytterbium, and barium) may be somewhat depleted in the soil with respect to the average rock composition. 4) Rocks display characteristic surface features of lunar material (impact microcraters, rounding) and shock effects similar to those observed in rocks and soil from the Apollo 11 and Apollo 12 missions. The rocks show no evidence of exposure to water, and their content of metallic iron suggests that they, like the Apollo 11 and Apollo 12 material, were formed and have remained in an environment with low oxygen activity. 5) The concentration of solar windimplanted material in the soil is large, as was the case for Apollo 11 and Apollo 12 soil. However, unlike previous fragmental rocks, Apollo 14 fragmental rocks possess solar wind contents ranging from approximately that of the soil to essentially zero, with most rocks investigated falling toward one extreme of this range. A positive correlation appears to exist between the solar wind components, carbon, and (20)Ne, of fragmental rocks and their friability (Fig. 12). 6) Carbon contents lie within the range of carbon contents for Apollo 11 and Apollo 12 samples. 7) Four fragmental rocks show surface exposure times (10 x 10(6) to 20 x 10(6) years) about an order of magnitude less than typical exposure times of Apollo 11 and Apollo 12 rocks. 8) A much broader range of soil mechanics properties was encountered at the Apollo 14 site than has been observed at the Apollo 11, Apollo 12, and Surveyor landing sites. At different points along the traverses of the Apollo 14 mission, lesser cohesion, coarser grain size, and greater resistance to penetration was found than at the Apollo 11 and Apollo 12 sites. These variations are indicative of a very complex, heterogeneous deposit. The soils are more poorly sorted, but the range of grain size is similar to those of the Apollo 11 and Apollo 12 soils. 9) No evidence of biological material has been found in the samples to date. 相似文献
15.
Data from total melt and step-by-step heating experiments on the Apollo 11 lunar samples suggest a close affinity between lunar and meteoritic rare gases. Trapped neon-20/neon-22 ratios range from 11.5 to approximately 15, resembling those for the gas-rich meteorites. Trapped krypton and xenon in the lunar fines and in the carbonaceous chondrites are similar except for an interesting underabundance of the heavy isotopes in both lunar gases which suggests that the fission component found in carbonaceous chondrites is depleted in lunar material. Spallation gases are in most cases quite close to meteoritic spallation gases in isotopic composition. 相似文献
16.
Data from the Apollo 15 and Apollo 16 laser altimeters reveal the first accurate elevation differences between distant features on both sides of the moon. The large far-side depression observed in the Apollo 15 data is not present in the Apollo 16 data. When the laser results are compared with elevations on maps from the Aeronautical Chart and Information Center, differences of 2 kilometers over a few hundred kilometers are detected in the Mare Nubium and Mare Tranquillitatis regions. The Apollo 16 data alone would put a 2-kilometer bulge toward the earth; however, the combined data are best fit by a sphere of radius 1737.7 kilometers. The offset of the center of gravity from the optical center is about 2 kilometers toward the earth and 1 kilometer eastward. The polar direction parameters are not well determined. 相似文献
17.
森林消防头盔的人机工程学分析 总被引：1，自引：0，他引：1
森林消防头盔的人机工程学设计与其安全性能紧密相关,为了提高森林消防头盔的安全性能,对国内应用广泛的3款消防头盔产品,从外形结构、材料、安全、舒适性等方面进行了性能评价.并根据消防员的使用情况进行数据分析,提出了使用悬挂系统、安装高度调节器、使用外设旋钮的可调式护目镜、分解使用头盔、护目镜、面罩等设计建议,为今后的森林消... 相似文献
18.
The number and length of etchable tracks, created by alpha particles in a cellulose nitrate sheet, are significantly enhanced by the application of an electric field across the cellulose nitrate. 相似文献
19.
The alpha particle spectrometer aboard the Apollo 15 command/service module was designed to detect alpha particles from radon decay and to locate regions with unusual activity on the moon. A significant increase in radon-222 activity was detected from a region containing the crater Aristarchus. The result is interpreted as probably indicating internal activity at the site. By analogy with terrestrial processes, increased radon emanation may be associated with the emission of other volatiles. 相似文献
20.
Tolansky S 《Science (New York, N.Y.)》1972,176(4035):671-673
Glass objects in the fines from the Apollo 11 and Apollo 12 missions are shown, by two-beam reflection interferometry, to have been subject to shock at temperatures below the melting or softening point of the glass. Possible causes for the glass fragmentation are discussed. 相似文献