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141.
An amended formula for the decay of radioactivematerial is presented. It is a modification of thestandard exponential formula. The new formula appliesfor long cosmic times comparable to the Hubble time. It reduces to the standard formula for shorttimes. It is shown that the material decays faster thanexpected. The application of the new formula to directmeasurements of the age of the universe and its implications are briefly discussed. 相似文献
142.
We have examined and subjected to analysis an exhaustive number of consumer products, including but not limited to lotions and cosmetics, herbal supplements, household cleaners, food items, and beverages. As a result we describe all those consumer products herein, to our knowledge, that are appropriately labelled as “Chemical free”. 相似文献
143.
Aleksey A. Goldberg Aleksey V. Shastin Valentine G. Nenajdenko 《Journal of fluorine chemistry》2010,131(3):384-5688
CF3CFBr2 was employed in catalytic olefination reactions of aromatic aldehydes. In situ prepared hydrazones of aldehydes were transformed to β-fluoro-β-(trifluoromethyl)styrenes by reaction with CF3CFBr2 under CuCl catalysis. Based on this reaction, a novel stereoselective approach towards β-fluoro-β-(trifluoromethyl)styrenes was elaborated. Nucleophilic vinylic substitution of fluorine by secondary amines, thiolates and alkoxides in β-fluoro-β-(trifluoromethyl)styrenes was also tested. 相似文献
144.
S. Yu. Torilov K. A. Gridnev V. I. Zherebchevsky M. Brenner L. I. Vinogradov V. Z. Goldberg T. V. Korovitskaya T. Lönnroth N. A. Maltsev M. Mutterer B. G. Novatskii M. Norrby J. M. K. Slotte Yu. G. Sobolev W. H. Trzaska G. P. Tyurin S. V. Khlebnikov 《JETP Letters》2011,94(1):6-10
High-spin states of the 22Ne nucleus in the excitation energy range of 15–30 MeV have been studied. The angular correlation method has been used to determine the spins of excited states. A number of new states with high angular momenta—20.0 MeV (9?), 20.7 MeV (11?), 21.6 MeV (9?), 22.2 MeV (12+), and 25.0 MeV (9?)—have been revealed. They are intensely populated in the reaction 14C(12C, α1)22Ne* → α2 + 18O and correspond to the rotational bands of various structures. 相似文献
145.
R.A. Vidal F. Bonetto J. Ferrón M.A. Romero Evelina A. García E.C. Goldberg 《Surface science》2011,605(1-2):18-23
In this paper we report measurements of the positive (H+) and negative (H?) ion fractions after H+ scattering from a highly oriented pyrolytic graphite (HOPG) surface. The experimental results show that for a fixed (large) exit angle the negative fraction is almost independent of the primary ion energy, while the positive fraction increases steadily. For a fixed incident energy, the H+ and H? fractions show a complementary behavior with exit angle. A dynamical quantum mechanical calculation, based on the localized and extended features of the atom–surface interaction, allows us to understand many of the features of the experimental results. 相似文献
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148.
We prove that any planar 4-web defines a unique projective structure in the plane in such a way that the leaves of the web
foliations are geodesics of this projective structure. We also find conditions for the projective structure mentioned above
to contain an affine symmetric connection, and conditions for a planar 4-web to be equivalent to a geodesic 4-web on an affine
symmetric surface. Similar results are obtained for planar d-webs, d>4, provided that additional d−4 second-order invariants vanish. 相似文献
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150.