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991.
An investigation on environmental background values was made in an area of about 1,140,000 km2, which included temperate and subtropical zones of China. The environmental background values of 142 soil environment units, 18 main soil types, 87 surface water environment units, 8 aquatic organism environment units and 20 underground water environment units were obtained. The rules, causes and effecting factors of regional differentiation of the environmental background values were deduced from over 200,000 various data. 相似文献
992.
We estimate the contribution of millisecond pulsars to the diffuse gamma-ray background of the Galaxy, and show that a significant
fraction of the Galactic background may originate from them. A small number of the unidentified COS-B point sources may, in
fact, be millisecond pulsars. It is argued that several hundred millisecond pulsars may be detectable as point sources by
the GRO satellite
A preliminary version of these results was presented at the NATO Advanced Study Institute on Neutron stars, AGNs and Jets,
Erice, September 5–17, 1988.
On leave from Raman Research Institute, Bangalore, India. 相似文献
993.
Reviving a calculation made by Eddington in the 1920s, and using the most recent and comprehensive databases available on
stars and galaxies, including more than 2,500,000 stars and around 20,000 galaxies we have computed their total radiation
received at the Earth just outside its atmosphere. This radiation density, if thermalized, would be equivalent to a temperature
of 4.212 K. The comparability of this temperature to that of the cosmic microwave background (2.723 K) may either be a pure
coincidence or may hold a key to some as yet unknown, aspect of the universe. 相似文献
994.
995.
Kunming Basin locates middle of Yunnan altiplano and has a particularity in geography, topographic and geological environment. With the urban dilation quickly, add the reason of the unreasonable city layout, conflicts between environment and urban resources consumption become shrill increasingly. It is human being activities that lead to vulnerability and depravation of geological environment in local. Take a few examples on geological environment to expatiate relationship between urban construction and geological environment carrying capacity, and find a way how to make a better plan for urban sustainable development to achieve new balance between man and nature in local. 相似文献
996.
We review recent findings that the universe on its largest scales shows hints of violations of statistical isotropy, in particular alignment with the geometry and direction of motion of the solar system, and missing power at scales greater than 60°. We present the evidence, attempts to explain it using astrophysical, cosmological or instrumental mechanisms, and prospects for future understanding. 相似文献
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