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41.
本文在适当的假设下.给出了某些变系数椭圆算子基本解间的一些关系.可用来研究一些椭圆算子解的性质.  相似文献   
42.
The exponential Radon transform, a generalization of the Radon transform, is defined and studied as a mapping of function spaces. It is represented in terms of Fourier transform of its domain and range, and this leads to the harmonic decomposition reconstruction. The results are similar results of Tretiak and Metz. Foundation item: Supported by the National Natural Science Foundation of China (No. 19971064), Key Project of Science and Technology of Hubei Province Education Committee. Biography: Wang Jin-ping (1963-), male, Ph.D. candidate, research direction: numberical solution of singular integral equation and integral transformation etc.  相似文献   
43.
We propose a multiple-tree overlay structure for resource discovery in unstructured P2P systems. Peers that have similar interests or hold similar type of resources will be grouped into a tree-like cluster. We exploit the heterogeneity of peers in each cluster by connecting peers with more capacities closer to the root of the tree. The capacity of a peer can be defined in different ways (e.g. higher network bandwidth, larger disk space, more data items of a certain type etc.) according to different needs of users or applications.  相似文献   
44.
In October 1924, The Physical Review, a relatively minor journal at the time, published a remarkable two-part paper by John H. Van Vleck, working in virtual isolation at the University of Minnesota. Using Bohr’s correspondence principle and Einstein’s quantum theory of radiation along with advanced techniques from classical mechanics, Van Vleck showed that quantum formulae for emission, absorption, and dispersion of radiation merge with their classical counterparts in the limit of high quantum numbers. For modern readers Van Vleck’s paper is much easier to follow than the famous paper by Kramers and Heisenberg on dispersion theory, which covers similar terrain and is widely credited to have led directly to Heisenberg’s Umdeutung paper. This makes Van Vleck’s paper extremely valuable for the reconstruction of the genesis of matrix mechanics. It also makes it tempting to ask why Van Vleck did not take the next step and develop matrix mechanics himself. This paper was written as part of a joint project in the history of quantum physics of the Max Planck Institut für Wissenschaftsgeschichte and the Fritz-Haber-Institut in Berlin.  相似文献   
45.
By analyzing the observation data from Dongchuan Debris Flow Observation and Research Station and historical data from year 1965 to 1990 gotten from National Astronomical Ob-servatories/Yunnan Observatory,the responding of debris flow in Jiangjia Ravine to Solar Proton Flare is studied. The following conclusion can be drawn. Solar Proton Flare,as one of most im-portant astronomical factors,affects the activity of debris flow in Yunnan. Generally,from 1965 to1990,the more active Solar Pro-ton Flare is,the greater the probability of high frequency and large runoff of debris flow is. On the contrary,the less active Solar Pro-ton Flare is,the greater the probability of low frequency,small runoff,and low sediment transport of debris flow is.  相似文献   
46.
The unified chaotic system contains the Lorenz system and the Chen system as two dual systems at the two extremes of its parameter spectrum. This paper presents the design of bang bang controller for unified system and multitude of numerical experiments under various control parameters. Numerical experiments meet the theoretic proof perfectly and convincingly demonstrated the controller can be effectively used for unified systems with uncertainty of the equilibrium points. The method enriches the applications of chaotic control. Foundation item: Supported by the National Natural Science Foundation of China(50209012) Biography: Deng Xiao-ming (1980-), male, Master candidate, research direction: chaos control.  相似文献   
47.
马克思主义哲学与文化创新的关系主要体现在:解放思想,实事求是是文化创新的世界观和方法论的基础;辩证的否定是实现文化创新的哲学方法:善于吸取总结群众的智慧与实践经验是文化创新的源泉;做好人才工作是文化创新的重要基础。  相似文献   
48.
研究晶体的生长形态与形成该形态的物理化学条件,最终控制显微结构的形成,是材料科学的重要研究任务。本文研究了工业应用的电熔AZS材料中出现斜锆石晶相,刚玉斜锆石共晶体、斜锆石-莫来石共晶体的形貌。从凝固过程出发,运用界面结构理论及成分过冷等概念,对AZS材料中各晶相的形貌及其形成的物理化学条件关联起来进行了讨论。  相似文献   
49.
Tris(tropolonato)neodimium( Ⅲ )has been prepared by the electrochemical oxidation of neodimium meral anode in acetonitrile solution of 2-hydroxy - 2,4,6 - cycloheptatrienone(tropolone). The unusual divalent neodimium complex was formed at the first step of electrosyn - thesis. The final product ,Nd (C7H6O2)3, has been characterized by microanalysis and the studies of IR and H, C3 NMR spectra.  相似文献   
50.
用缩管法设计球铁铸件冒口时,为了既保证铸件质量,又节约金属,提高工艺出品率,采用了向下逐渐增大冒口直径,即所谓锥形冒口,本文介绍了球铁锥形冒口的设计方法及其需注意的问题,并用C语言设计编制了计算机程序  相似文献   
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