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81.
Wulan Hasi 《东北数学》1995,(3)
Hardy-LittlewoodTheoremsinMixedNormSpacesonBoundedSymmetricDomainofC~n¥(乌兰哈斯)WulanHasi(DepartmentofMathematics,InnerMongoliaN?.. 相似文献
82.
对于CONT的任意一个笛卡儿闭的满子范畴C,构造CONT的两个新的满子范畴R-C(以C对象的收缩为对象的范畴)和B-C(以C扩张序列的双极限为对象的范畴),并证明了它们都是笛卡儿闭范畴。由于R-C和B-C都包含C为其满子范畴,利用上述结果可得CONT的极大笛卡儿闭子范畴必对收缩和双极限封闭。本文还从范畴笛卡儿闭性的角度给出了Domain理论中一个公开问题的等价描述。 相似文献
83.
Infinite element computations are very efficient for predicting the vibro-acoustic response and sensitivities of a vibrating structure for an exterior acoustic domain. In addition, domain decomposition methods are very powerful algorithms for solving large linear systems in parallel. In this paper, an infinite element method is proposed and analyzed for parallel computations purpose. An original formulation of this method with Lagrange multipliers defined on (semi-)infinite space is presented. The implementation aspects of this method in an industrial acoustic software (SYSNOISE) are discussed. New numerical results illustrate the efficiency of the proposed method for realistic acoustical radiation problems. 相似文献
84.
This paper presents a theoretical formulation in which the stream-tube method (STM) is examined through a variational approach for solving solid strain and fluid flow problems with finite elements. The analysis considers a reference domain, used as computational domain, related to the physical domain by an unknown transformation function to be determined numerically. Mass conservation is automatically verified by STM. The variational approach leads to eliminate the pressure in fluid problems and avoids to set up a mixed displacement–pressure procedure in the case of incompressible solids. Examples are given for fluid flows, applications and comparisons are also provided in the bending problem in elasticity. 相似文献
85.
本文对关于HJB方程的拟变分不等式提出了松弛算法,也给出了基于上述算法的区域分解方法,并建立了相应的收敛性定理。 相似文献
86.
偏序集上的滤子极大理想 总被引:3,自引:1,他引:2
在偏序集上引入并考察了滤子极大理想的概念,证明了相应的存在性定理。引入并考察了伪极大元和伪既约元的概念,利用图表的形式对连续格中各种类型的既约元和素元之间的关系进行了归纳总结,完善了文献《Continuous Lattices and Domains》(作者:G.Gierz,et al)中的一个图表的相关内容,填补了在分配的连续格情形该图表的一个未知内容,部分地回答了该文献中的一个问题。 相似文献
87.
The temperature dependence of magnetic domain walls in ferromagnetic systems with strong exchange coupling and weak lattice anisotropy is studied assuming that the thermal influence results mainly from the temperature dependence of the magnetization. We obtain that in lattices with an uniaxial symmetry like Co the wall width increases with temperature, but stays finite up to the Curie temperature Tc. In contrary, for a cubic lattice like Fe the wall width diverges for T → Tc, if only the lattice anisotropy is taken into account. The shape of the domain walls is not conserved, since at Tc the wall is determined only by the lowest order of anisotropy. In addition, the temperature dependence of a domain wall width for a thin magnetic film is determined. Using a special symmetry, we obtain a diverging wall width at a temperature markedly lower than Tc. However, the consideration of additional domain wall modes should modify this result. 相似文献
88.
P. Podio-Guidugli G. Tomassetti 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,26(2):191-198
A new derivation is presented of Walker's exact solution to Gilbert equation, a solution which mimicks the travelling-wave
motion of a flat domain wall at 180°. It is shown that a process during which the working of the applied magnetic field exactly compensates dissipation (the Walker
condition) exists both under the constitutive circumstances considered in the standard Gilbert equation and when either the
internal free-energy or the dissipation, or both, are generalized by the introduction of higher-gradient terms; but that such
a process cannot solve the generalized Gilbert equation. It is also shown that, when dry-friction dissipation is considered
and a suitable magnetic field is applied, the associated Gilbert equation has a Walker-type solution mimicking a flat wall,
at 90° this time, which however does not satisfy the Walker condition.
Received 16 November 2001 相似文献
89.
A method to study domain structure in ferroelectrics, using pyroelectric effect is described. Variation of pyroelectric signal
from the surface of a triglycine sulphate crystal plate has been studied by scanning the surface of the crystal with a low
wattage He-Ne laser beam. The integrated pyroelectric signal is due to two components, namely, (1) the primary component arising
out of the change in spontaneous polarization with temperature and (2) the delayed component arising out of the possible polarization
reversal. The component of an electric field along the ferroelectric axis due to thermal hemisphere within the crystal plate
formed by the laser beam has been calculated and shown to exceed coercive field, making polarization reversal possible. The
delayed pyroelectric signal is a measure of polarization reversal within the patch illuminated and its observed variation
over the surface yields information of the domain structure. 相似文献
90.
At recent, Hourgat et gave a domain decomposition algorithm for elliptic problems which can be implemented in parallel. Many numerical experiments have illustrated its efficiency. In the present paper, we apply this algorithm to solve the discrete parabolic problems, analyse its convergence and show that its convergence rale is about (1 - 2p + σp2 ) which is nearly optimal and independent of the parameter τ, where σ τ O((1 +H )(1 + ln(H / h))2 ). 0 < p < 1 / σ,τ,h,H are the time step size, finite element parameter and subdomain diameter, respectively. 相似文献