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951.
952.
Joseph Shipman 《Mathematical Intelligencer》2007,29(4):9-14
Theorems 2 and 3 establish the minimum algebraic conditions necessary for a field to be algebraically closed, and they can
therefore be said to “optimize” the Fundamental Theorem of Algebra. But each specific“degree implication” is a first-order
consequence of the axioms for fields, and could have been discovered two centuries ago; the existence of these finitary relationships
appears to have been unsuspected by practically everyone, with one important exception. 相似文献
953.
Ling-yan Tang Song-he Song 《应用数学学报(英文版)》2007,23(2):303-310
In this paper,we use Daubechies scaling functions as test functions for the Galerkin method,and discuss Wavelet-Galerkin solutions for the Hamilton-Jacobi equations.It can be proved that the schemesare TVD schemes.Numerical tests indicate that the schemes are suitable for the Hamilton-Jacobi equations.Furthermore,they have high-order accuracy in smooth regions and good resolution of singularities. 相似文献
954.
A. M. Kharitonov 《Thermophysics and Aeromechanics》2007,14(1):3-11
Sergey Alekseevich Khristianovich is one of the famous Russian mechanical engineers of the 20th century together with N.E.
Zhukovsky, S.A. Chaplygin, N.E. Kochin, and others. He made an immense contribution to some aspects of mechanics, such as
aerogasdynamics, rock mechanics, theory of plasticity, filtration theory, and environmental power engineering. All this was
preceded by a long, hard, and fruitful life full of outstanding events. 相似文献
955.
Historians have always seen jabr (restoration) and muqābala (confrontation) as technical terms for specific operations in Arabic algebra. This assumption clashes with the fact that the words were used in a variety of contexts. By examining the different uses of jabr, muqābala, ikmāl (completion), and radd (returning) in the worked-out problems of several medieval mathematics texts, we show that they are really nontechnical words used to name the immediate goals of particular steps. We also find that the phrase al-jabr wa'l-muqābala was first used within the solutions of problems to mean al-jabr and/or al-muqābala, and from there it became the name of the art of algebra. 相似文献
956.
E. Granot S. Sternklar D. Schermann Y. Ben-Aderet M.H. Itzhaq 《Applied physics. B, Lasers and optics》2006,82(3):359-362
We use the spectral ballistic imaging technique to measure the impulse response of a Fabry–Pérot etalon with less than 0.2 ps
temporal resolution. The results show excellent agreement with the theoretical predictions and negligible noise. Comparison
to the Kramers–Kronig method along with its limitations is also presented.
PACS 42.65.Re; 07.60.Ly; 42.30.Kq 相似文献
957.
M. Gai 《Physics of Atomic Nuclei》2006,69(11):1805-1811
The Standard Solar Model (BP04) predicts a total 8B neutrino flux that is 17.2% larger than that measured in the salt phase of the SNO detector (and if it is significant, it
will indicate oscillation to sterile neutrinos). Hence, it is important to examine in detail the uncertainties (and values)
of inputs to the BP04. Currently, the largest fractional uncertainty is due to the new evaluation of the surface composition
of the Sun. We examine the nuclear input on the formation of solar 8B [S
17(0)] and demonstrate that it is still quite uncertain due to the ill-known slope of the measured astrophysical cross section
factor and thus illdefined extrapolation to zero energy. This yields an additional reasonable uncertainty due to extrapolation
of
−3.0
+0.0
eV b (
−14%
+0%
). Since a large discrepancy exists between measured as well as predicted slopes, the value of S
17(0) is dependent on the choice of data and theory used to extrapolate S
17(0). This situation must be alleviated by new measurement(s). The “world average” is driven by the Seattle result owing to
the very small quoted uncertainty, which we, however, demonstrate to be an overestimated accuracy. We propose more realistic
error bars for the Seattle results based on the published Seattle data.
The text was submitted by the author in English. 相似文献
958.
Current techniques of water wave visualization such as shadowgraphy and stereo photography are widely used but are deficient
in many aspects. Refraction based visualization observes the bending of light as it traverses across a liquid-air interface.
This work describes the continued development of techniques to measure the surface height of a liquid free surface. The method,
Reference Image Topography, utilizes refraction of light at the free surface as a function of the local angle of that surface.
Particle Image Velocimetry (PIV) software is used to evaluate apparent dislocations of the target image viewed through the
free surface, which are approximately proportional to the surface angle. High-resolution images are presented of the dynamic
surface topography for a point source and the shallow water flow around a vertical cylinder. 相似文献
959.
960.