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941.
An analogue to the theory of Riesz potentials and Liouville operators in R
n
for arbitrary fractal d-sets is developed. Corresponding function spaces agree with traces of Euclidean Besov spaces on fractals. By means of associated quadratic forms we construct strongly continuous semigroups with Liouville operators as infinitesimal generator. The case of Dirichlet forms is discussed separately. As an example of related pseudodifferential equations the fractional heat-type equation is solved. 相似文献
942.
提出利用四叉树自适应图像划分、源块池柔性分类并结合人类视觉特性的高速分形图像编码算法.与其它同类算法相比,该算法在编码速度、压缩比和图像质量等方面均有显著提高. 相似文献
943.
The effects of thermal dispersion and thermal stratification on mixed convection about a vertical surface in a porous medium
are studied. The conservation equations that govern the problem are reduced to a system of nonlinear ordinary differential
equations. The resulting equations are solved on the basis of the local similarity approximation. The results indicate that
both dispersion and stratification effects have considerable influence on the heat transfer rate. 相似文献
944.
This paper presents an extension of the generalized multipole technique (GMT) for 2D anisotropic scatterers. New expansions similar to the Bessel multipole expansion are derived for arbitrary anisotropic media. Numerical simulations prove the accuracy and the rapid convergence of these expansions. As the results obtained are extremely accurate, this technique is most helpful for the evaluation of reference solutions and for the understanding of the physical interaction of light with arbitrary anisotropic media. 相似文献
945.
R L Ehman G E Wesbey K L Moon R D Williams M T McNamara W R Couet T N Tozer R C Brasch 《Magnetic resonance imaging》1985,3(1):89-97
Nitroxyl spin labels have been shown to be effective in vivo contrast agents for magnetic resonance imaging (MRI) of the central nervous system, myocardium, and urinary tract. A new pyrrolidine nitroxyl contrast agent (PCA) with better resistance to in vivo metabolic inactivation than previously tested agents was studied for its potential to enhance subcutaneous neoplasms in an animal model. Twenty-two contrast enhancement trials were performed on a total of 15 animals 4-6 weeks after implantation with human renal adenocarcinoma. Spin echo imaging was performed using a .35 T animal imager before and after intravenous administration of PCA in doses ranging from 0.5 to 3mM/kg. The intensity of tumor tissue in the images increased an average of 35% in animals receiving a dose of 3 mM/kg. The average enhancement with smaller doses was proportionately less. Tumor intensity reached a maximum within 15 min of injection. The average intensity difference between tumor and adjacent skeletal muscle more than doubled following administration of 3 mM/kg of PCA. Well-perfused tumor tissue was more intensely enhanced than adjacent poorly perfused and necrotic tissue. 相似文献
946.
J. Machta M. H. Ernst H. van Beijeren J. R. Dorfman 《Journal of statistical physics》1984,35(3-4):413-442
In a previous paper we developed a mode-coupling theory to describe the long time properties of diffusion in stationary, statistically homogeneous, random media. Here the general theory is applied to deterministic and stochastic Lorentz models and several hopping models. The mode-coupling theory predicts that the amplitudes of the long time tails for these systems are determined by spatial fluctuations in a coarse-grained diffusion coefficient and a coarse-grained free volume. For one-dimensional models these amplitudes can be evaluated, and the mode-coupling theory is shown to agree with exact solutions obtained for these models. For higher-dimensional Lorentz models the formal theory yields expressions which are difficult to evaluate. For these models we develop an approximation scheme based upon projecting fluctuations in the diffusion coefficient and free volume onto fluctuations in the density of scatterers.Work supported by grant No. CHE 77-16308 from the National Science Foundation and by a Nato Travel Grant. 相似文献
947.
Manojit Pal Venkataraman SubramanianKaruppasamy Parasuraman Koteswar Rao Yeleswarapu 《Tetrahedron》2003,59(48):9563-9570
(S)-Prolinol facilitated the coupling reaction of terminal alkynes with 3-iodoflavone under palladium-copper catalysis in aqueous DMF affording a mild and convenient method for the synthesis of 3-alkynyl substituted flavones of potential biological interest. 相似文献
948.
1.IntroductionIn[41,GhidagliaprovedthatforthedissipativeKdVequation:withperiodicboundaryconditionu(x,t)=u(x L,t),thereexistsaweakglobalattractoroffinitedimension.Recently,[7]obtainedasimilarresultfortheperiodicboundaryproblemwhereor>0,g/0,7>0,fEC'(R),If15A]ul'--',6>0,Gi(0,0)=0,i=1,2andforevery(CI,'2)eR',However,feweffortsaredevotedtotheexistenceofglobalattractorinunboundeddomain.Themaindifficultinthiscaseliesinthatthelinearprincipleoperatorisnothavecompactresolventoperatorandthuswecannot… 相似文献
949.
Sliding of self-similar sets 总被引:2,自引:0,他引:2
Li-feng XI Huo-jun RUAN & Qiu-li GUO Institute of Mathematics Zhejiang Wanli University Ningbo China Department of Mathematics Zhejiang University Hangzhou China 《中国科学A辑(英文版)》2007,50(3):351-360
This paper deals with the Lipschitz equivalence of slidings of self-similar sets by graph-directed construction and martingale theory. 相似文献
950.
利用谱表示理论和微扰展开法,从理论上给出了适合于一般微结构复合体系的有效非线性响 应的一般表示式,并结合有效媒质近似(EMA),在弱非线性条件下研究了由三阶非线性组 分(体积分数为p)和线性组分构成的非线性复合体系的有效非线性响应,讨论了复合 体系的有效介电常数ε~e=εe+χe|E0|2+ηe|E0| 4中的有效三次非线性响应χe和有效高次非线性响应ηe与体积分数p和 退极化因子L之间的关系,分析了非线性组分的介电常数为复数情形时体系的有效高阶非线 性响应,从理论上说明了组分的高次非线性响应对整个复合体系的有效介电常数的影响.
关键词:
非线性复合介质
有效非线性响应
谱表示理论 相似文献