排序方式: 共有51条查询结果,搜索用时 31 毫秒
1.
L. Narici M. Casolino L. Di Fino M. Larosa O. Larsson P. Picozza V. Zaconte 《Radiation measurements》2012,47(10):1030-1034
Iron abundance in cosmic rays impinging on astronauts in space habitats is of paramount importance when calculating the radiation risk for human space exploration. The concurrent high relative abundance of iron in Galactic Cosmic Rays (GCR) and iron ability to produce damages at cellular and molecular levels, together with recent radiobiology results suggests iron as a major candidate to be studied in order to produce accurate radiation hazard assessments. Iron may be in fact responsible for a large percentage of cancer risk during a long interplanetary voyage, and therefore deserves a specific attention. We built a simple model based on CREME96 for the radiation in the International Space Station (ISS) and tested it against recently performed measurements with the ALTEA and Alteino particle detectors. While we can report a good agreement between 50m and 250 keV/μm (very good for several peaks such as Si, Mg, S) we show an overestimation by this model of iron abundances of about 25–80% when compared to the measurements. New analysis on previously published work, supporting this result, are also reported.Reasons for this overestimation are discussed, they are likely to be related to the not detailed enough transport through the multiplicity of the ISS shielding and to the often used simplification of “aluminum equivalent shielding”. The iron sources in LEO, possibly not yet accurate enough when transported in Low Earth Orbit, can also play a role. New concurrent measurements (inside–outside the ISS) are suggested to help resolving this issue. 相似文献
2.
H. A. Freye A. Soltys M. Francis J. Fino und F. Kaufman 《Fresenius' Journal of Analytical Chemistry》1937,111(7-8):281-283
Ohne Zusammenfassung 相似文献
3.
H. A. Freye A. Soltys M. Francis J. Fino F. Kaufman 《Analytical and bioanalytical chemistry》1937,111(7-8):281-283
4.
We obtain a generalization of the Kodaira-Morrow stability theorem for cosymplectic structures. We investigate cosymplectic
geometry on Lie groups and on their compact quotients by uniform discrete subgroups. In this way we show that a compact solvmanifold
admits a cosymplectic structure if and only if it is a finite quotient of a torus. 相似文献
5.
Veronica Zaconte Marco Casolino Luca Di Fino Chiara La Tessa Marianna Larosa Livio Narici Piergiorgio Picozza 《Radiation measurements》2010,45(2):168-172
The ALTEA (Anomalous Long Term Effects on Astronauts) detector was used to characterize the radiation environment inside the USLab of the International Space Station (ISS), where it measured the abundances of ions from Be to Fe. We compare the ALTEA results with Alteino results obtained in the PIRS module of the Russian segment of the ISS, and normalize to the high energy Si abundances given by Simpson. These are the first particle spectral measurements, which include ions up to Fe, performed in the USLab. The small differences observed between those made inside the USLab and the Simpson abundances can be attributed to the transport through the spacecraft hull. However, the low abundance of Fe cannot be attributed to only this process. 相似文献
6.
The large time behavior of non-negative solutions to the reaction–diffusion equation ?t u=-(-D)a/2u - up{\partial_t u=-(-\Delta)^{\alpha/2}u - u^p}, ${(\alpha\in(0,2], \;p > 1)}${(\alpha\in(0,2], \;p > 1)} posed on
\mathbbRN{\mathbb{R}^N} and supplemented with an integrable initial condition is studied. We show that the anomalous diffusion term determines the
large time asymptotics for p > 1 + α/N, while nonlinear effects win if p ≤ 1 + α/N. 相似文献
7.
Raphaël Fino 《Central European Journal of Mathematics》2013,11(6):1068-1077
We prove certain results comparing rationality of algebraic cycles over the function field of a quadric and over the base field. These results have already been obtained by Alexander Vishik in the case of characteristic 0, which allowed him to work with algebraic cobordism theory. Our proofs use the modulo 2 Steenrod operations in the Chow theory and work in any characteristic ≠ 2. 相似文献
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9.
We study the existence of left invariant closed \(G_2\)-structures defining a Ricci soliton metric on simply connected nonabelian nilpotent Lie groups. For each one of these \(G_2\)-structures, we show long time existence and uniqueness of solution for the Laplacian flow on the noncompact manifold. Moreover, considering the Laplacian flow on the associated Lie algebra as a bracket flow on \({\mathbb {R}}^7\) in a similar way as in Lauret (Commun Anal Geom 19(5):831–854, 2011) we prove that the underlying metrics \(g(t)\) of the solution converge smoothly, up to pull-back by time-dependent diffeomorphisms, to a flat metric, uniformly on compact sets in the nilpotent Lie group, as \(t\) goes to infinity. 相似文献
10.
Anna Fino 《Advances in Mathematics》2009,221(3):914-935
On a compact complex manifold we study the behaviour of strong Kähler with torsion (strong KT) structures under small deformations of the complex structure and the problem of extension of a strong KT metric. In this context we obtain the analogous result of Miyaoka extension theorem. Studying the blow-up of a strong KT manifold at a point or along a complex submanifold, we prove that a complex orbifold endowed with a strong KT metric admits a strong KT resolution. In this way we obtain new examples of compact simply-connected strong KT manifolds. 相似文献