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241.
242.
243.
We present some algorithms related to rings of Ore polynomials (or, briefly, Ore rings) and describe a computer algebra library
for basic operations in an arbitrary Ore ring. The library can be used as a basis for various algorithms in Ore rings, in
particular, in differential, shift, and q-shift rings.
__________
Translated from Sovremennaya Matematika i Ee Prilozheniya (Contemporary Mathematics and Its Applications), Vol. 13, Algebra,
2004. 相似文献
244.
本文提出的MMD算法用于提高模型区别错误信息和正确信息的能力.利用该算法在对模型的参数进行重估计时.涉及到复杂的目标函数的梯度运算.击运用矩阵运算使得梯度运算变得简单明了,因此本文给出了MMD算法下的HMM参数重估计的矩阵表示形式并给出了证明. 相似文献
245.
Complex impedance spectra were obtained on a crystal of CaCu3Ti4O12 (CCTO) from 289 to 456 K. As in the case of ceramic CCTO, these spectra can be interpreted as arising from a conducting material containing insulating barriers. This is then further evidence for the existence of planar defects within crystals of CCTO that act as insulating barriers and produce the large dielectric constant through a space charge mechanism. 相似文献
246.
We investigate the two methods of defining the surface gravity ,κ on the horizon, which are the metric definition and the definition given by the spacetime conformal method. It is found that the latter is of greater generality. By this method, we find that ,κ of η- ξ spacetime is equal to the exponent factor α in the coordinate transformation, which confirms the argument that η- ξ spacetime can be considered as the background spacetime for finitetemperature field theories. The reasons why the metric definition of ,κ can not be applied in η- ξ spacetime are presented. 相似文献
247.
We present the cosmological solutions in the six-dimensional Einstein-gauge theory to which is added a matter term. The general behavior of the scale factors of the ordinary (R3) and extra (R2) dimensions can be depicted in four stages. Stage 1: Both R3 and R2 expand. Stage 2: R2 is a constant and R3 is an inflationary solution. Stage 3: R2 recollapses towards its minimum value, R3 will continue to increase monotonically. Stage 4: R2 stabilizes at RKK and R3 expands in the usual FRW way, while the four-dimensional cosmological constant becomes zero. 相似文献
248.
激光晶体YAG中Er3+的辐射跃迁 总被引:2,自引:0,他引:2
本文讨论和分析了激光晶体YAG中Er3+离子的激光上能级的4S3/2、4I11/2和4I13/2辐射跃迁的有关因素。 相似文献
249.
J.-F. Pascual-Sánchez A. San Miguel F. Vicente 《General Relativity and Gravitation》2004,36(9):2075-2083
We analyze the geometry of a rotating disk with a tangential acceleration in the framework of the theory of Special Relativity, using the kinematic linear differential system that verifies the relative position vector of time-like curves in a Fermi reference. A numerical integration of these equations for a generic initial value problem is made up and the results are compared with those obtained in other works. 相似文献
250.
The title compound, [Cd(SeCN)2(pyCN)2]∞, adopts an extended one‐dimensional chain structure in which the neighboring cadmium atoms are bridged by two selenocyanate ions. The central cadmium atom has a distorted octahedral geometry defined by two isonicotinonitrile and four selenocyanate ions in a 4N2Se fashion. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献