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21.
Square‐planar d8‐ML4 complexes might display subtle but noticeable local Lewis acidic sites in axial direction in the valence shell of the metal atom. These sites of local charge depletion provide the electronic prerequisites to establish weakly attractive 3c–2e M⋅⋅⋅H C agostic interactions, in contrast to earlier assumptions. Furthermore, we show that the use of the sign of the 1H NMR shifts as major criterion to classify M⋅⋅⋅H C interactions as attractive (agostic) or repulsive (anagostic) can be dubious. We therefore suggest a new characterization method to probe the response of these M⋅⋅⋅H C interactions under pressure by combined high pressure IR and diffraction studies.  相似文献   
22.
陈雁萍  蔡诗东 《中国科学A辑》1993,36(10):1047-1053
本文讨论了离子声等离子体波的激发条件和它们对荷电粒子间相互作用势的动力屏蔽效应.对一些具有两个未完全被充满的外层电子能带的金属,计算了这种屏蔽效应,并研究了此动力效应对金属钯中氘-氘聚变反应率的影响.  相似文献   
23.
Square‐planar d8‐ML4 complexes might display subtle but noticeable local Lewis acidic sites in axial direction in the valence shell of the metal atom. These sites of local charge depletion provide the electronic prerequisites to establish weakly attractive 3c–2e M???H? C agostic interactions, in contrast to earlier assumptions. Furthermore, we show that the use of the sign of the 1H NMR shifts as major criterion to classify M???H? C interactions as attractive (agostic) or repulsive (anagostic) can be dubious. We therefore suggest a new characterization method to probe the response of these M???H? C interactions under pressure by combined high pressure IR and diffraction studies.  相似文献   
24.
We report the results of doping- and pressure-dependent experimental investigations on the low-dimensional Mott-Hubbard insulators TiOCl and TiOBr. As observed by photoelectron spectroscopy, doping with Na and K shifts the valence band to higher binding energies associated with a jump of the chemical potential. With increasing doping, a broad hump develops close to the Fermi energy and the energy gap “softens”. The application of pressure induces the appearance of spectral weight close to the Fermi energy, as probed by infrared transmittance and reflectance measurements. The pressure-induced changes in the electronic properties coincide with a structural phase transition according to powder X-ray diffraction studies under pressure. The experimental findings are compared to theoretical predictions.  相似文献   
25.
We introduce the set of bicomplex numbers which is a commutative ring with zero divisors defined by where We present the conjugates and the moduli associated with the bicomplex numbers. Then we study the bicomplex Schr?dinger equation and found the continuity equations. The discrete symmetries of the system of equations describing the bicomplex Schr?dinger equation are obtained. Finally, we study the bicomplex Born formulas under the discrete symmetries. We obtain the standard Born’s formula for the class of bicomplex wave functions having a null hyperbolic angle.  相似文献   
26.
Auslender, Cominetti and Haddou have studied, in the convex case, a new family of penalty/barrier functions. In this paper, we analyze the asymptotic behavior of augmented penalty algorithms using those penalty functions under the usual second order sufficient optimality conditions, and present order of convergence results (superlinear convergence with order of convergence 4/3). Those results are related to the analysis of pure penalty algorithms, as well as augmented penalty using a quadratic penalty function. Limited numerical examples are presented to appreciate the practical impact of this local asymptotic analysis.This research was partially supported by NSERC grant OGP0005491  相似文献   
27.
多尺度B样条小波边缘检测算子   总被引:4,自引:0,他引:4       下载免费PDF全文
基于B样条理论提出了一类新的多尺度小波变换,通过其零交叉或模极值能有效地表示和检测信号或图象的边缘,对任意n次B样条,导出了相应的分解和重建的快速算法,对应的用于分解和重建的滤波器的时域和频域响应也被精确地给出.从时频局部化的角度对不同次数的B样条作了分析,认为3次B样条小波在边缘提取等实际应用中是渐近最优的,结果也为B样条小波在立体视觉匹配、滤噪等方面的进一步应用提供了基础.  相似文献   
28.
PARALLEL AUXILIARY SPACE AMG FOR H(curl) PROBLEMS   总被引:2,自引:0,他引:2  
In this paper we review a number of auxiliary space based preconditioners for the second order definite and semi-definite Maxwell problems discretized with the lowest order Nedelec finite elements. We discuss the parallel implementation of the most promising of these methods, the ones derived from the recent Hiptmair-Xu (HX) auxiliary space decomposition [Hiptmair and Xu, SIAM J. Numer. Anal., 45 (2007), pp. 2483-2509]. An extensive set of numerical experiments demonstrate the scalability of our implementation on large-scale H(curl) problems.  相似文献   
29.
蔡祖泉 《中国科学A辑》1974,17(2):109-110
历代反动派总是宣扬孔老二“上智与下愚不移”的唯心论说教,把它作为“剥削有理”、“压迫有理”的根据。林彪这个地主资产阶级的代理人,为了篡党夺权,复辟资本主义,建立林家法西斯王朝,也鼓吹“上智下愚”的谬论。他把自己吹成“生而知之”的“天才”,以“至贵”、超人自居,污蔑劳动人民“愚昧”、“落后”,只会说“恭喜发财”,只能想“油盐酱醋柴”。  相似文献   
30.
低温等离子体转化NO/O2/N2气氛中NO的实验研究   总被引:1,自引:0,他引:1  
王军  蔡忆昔  王攀  庄凤芝  冉冬立 《化学学报》2009,67(20):2315-2318
通过建立低温等离子体实验系统, 研究了介质阻挡放电型低温等离子体反应器作用于NO/O2/N2混合气体系时, NO, O2初始浓度对NO的转化效率的影响以及NOx, O3浓度随能量密度的变化关系. 低温等离子体作用于NO/O2/N2混合气体系时, NO同时发生氧化还原反应, 氧化反应占主导地位, 大部分NO转化为NO2; NO转化率随O2, NO初始浓度增大而降低, 能量密度在450~600 J/L时转化率较高; 产生的O3浓度随能量密度的增大呈先增后减的趋势.  相似文献   
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