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考虑了具有结构阻尼和外阻尼的非自治非线性粘弹性梁方程的拉回D_δ,E_1-吸引子.首先利用Galerkin方法,证明了在齐次边界条件和初始条件下系统在V×H和D(A)×V中的整体解的存在唯一性;其次通过先验估计,证明了系统的拉回吸收集的存在性;最后证明了系统满足拉回D_δ,E_1-条件(C),从而证明了系统的强拉回D_δ,E_1-吸引子的存在性. 相似文献
185.
Tadashi Kobayashi Hiratoshi Katsuda Yukio Sakabe Kiyoshi Iwai Seiji Kanba 《Phase Transitions》2013,86(3):215-223
EPR spectra of superconducting YBa2Cu3O7-δ and insulating Y2BaCuO5 have been examined. The intensity of Cu2+ ions in YBa2Cu3O7-δ is about 1/3000 of that in Y2BaCuO5 at room temperature. Owing to the Meissner effect in the superconducting state, the EPR signal of Cu2+ ions in YBa2Cu3O7-δ disappears; moreover the EPR signal of DPPH deposited on the YBa2Cu3O7-δ specimen is shifted. An additional EPR line is found for YBa2(Cu2.94Cr0.06)O7-δ at temperatures below 113K; this can be related to the phenomenon of superconductivity. 相似文献
186.
S. Mazumder H. Rajagopal A. Sequeira Jagriti Singh A. K. Rajarajan L. C. Gupta 《Phase Transitions》2013,86(1-3):97-105
Effects of doping YBa2Cu3O7-δ with Mg and Zn on its crystallographic structure and superconducting behaviour have been investigated. Orthorhombic structure is retained upto Mg/Cu ratio of 0.12 (the highest investigated here), but Tc decreases rapidly with the level of Mg-doping. The effects produced by Mg-doping are very similar to those due to Zn-doping investigated by the present authors as well as by others. Neutron diffraction measurements have been carried out on two substituted materials: YBa2Cu2.82Mg0.18O7-δ and YBa2Cu2.82Zn0.18O7-δ. Both Mg- and Zn-dopants show strong tendency of occupying Cu(II)-sites in the unit cell. In the case of Mg-doping, however, a strikingly different feature is the concomitant depletion of oxygen at the O3-sites by an amount nearly equal to the Mg-concentration. 相似文献
187.
H. Venker 《辐射效应与固体损伤》2013,168(3):209-210
Abstract Photoluniinescence of Solutions. C. A. Parker, American Elsevier Publishing Company, Inc., New York, 1968. $30.00 The Radiation Belt and Magnetosphere. Wilmot N. Hess, Blaisdell Publishing Company, New York, 1968, 548 pages. $16.50 Radiation Dosimetry. F. H. Attix and W. C. Roesch Academic Press, New York Vol. I, 1968, 405 pages. $19.50 Vol. 11, 1966,462 pages. $20.00 Radiation Effects in Semiconductor Devices. F. Larin, John Wiley &; Sons, New York, 1968,287 pages. $11.95 相似文献
188.
Abstract Natural nitrogen isotope ratios were measured in different compartments (needles or leaves and twigs of different age classes and crown positions, roots and soil of different horizons) of spruce (Picea abies), larch (Larix decidua) and beech (Fagus sylvatica) trees in an 11-year-old mixed stand in the Fichtelgebirge, NE Bavaria, Germany. In addition, samples of understorey vegetation (mainly ericaceous shrubs and grass) and of ectomycorrhizal and saprophytic fungi were analyzed. The δ15N values found for all samples ranged between ?7.5 and + 4.5‰. No significant differences were found for the nitrogen isotope ratios of the three tree species despite of their evergreen versus deciduous foliage and despite of their different rooting depth. Ericaceous shrubs had the most negative and fungi and soil from the mineral horizon the most positive δ15N values. Positive δ15N values of the fungi indicate their ability to utilize organic soil nitrogen, but the data do not unequivocally show that plants forming mycorrhizas profit from this organic nitrogen source. 相似文献
189.
本文研究了空间X中具有一定性质的子集可度量化的问题.利用一般拓扑学证明一个空间可度量的方法,得到如下结论:若正则空间具有与其有界子集有关的正则Gδ对角线,那么该子集的闭包是可度量化的;若正则空间具有与其有界强零集A有关的Gδ对角线,那么该子集A是X的紧可度量的子空间,推广了文献[1,2]的结果. 相似文献
190.
Abstract Electrochemical lithium intercalation into Li1-δMn2O4 electrode prepared by sol-gel method was investigated from the thermodynamic view point by using galvanostatic intermittent titration technique (GITT) combined with EMF-temperature measurement. The electrode potential vs. lithium content curve was theoretically calculated with the aid of the lattice gas model based upon the Bragg-Williams approximation for the cubic spinel composed of two sub-lattices. Considering the considerable difference between both lithium contents in two sub-lattices due to the ordering of the intercalated lithium ions, the theoretical partial molar enthalpy and entropy were calculated at various lithium contents by a numerical method. From the comparison between the theoretical partial molar quantities and experimental results, the electrochemical lithium intercalation into the Li1-δMn2O4 electrode was discussed in terms of the ordering of the intercalated lithium ions. 相似文献