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991.
Z.H. Zhang X.L. Zhong H. Liao F. Wang J.B. Wang Y.C. Zhou 《Applied Surface Science》2011,257(17):7461-7465
In the present work, X-ray photoelectron spectroscopy (XPS) was used to investigate the composition depth profiles of Bi3.15Nd0.85Ti3O12 (BNT) ferroelectric thin film, which was prepared on Pt(1 1 1)/Ti/SiO2/Si(1 0 0) substrates by chemical solution deposition (CSD). It is shown that there are three distinct regions formed in BNT film, which are surface layer, bulk film and interface layer. The surface of film is found to consist of one outermost Bi-rich region. High resolution spectra of the O 1s peak in the surface can be decomposed into two components of metallic oxide oxygen and surface adsorbed oxygen. The distribution of component elements is nearly uniform within the bulk film. In the bulk film, high resolution XPS spectra of O 1s, Bi 4f, Nd 3d, Ti 2p are in agreement with the element chemical states of the BNT system. The interfacial layer is formed through the interdiffusion between the BNT film and Pt electrode. In addition, the Ar+-ion sputtering changes lots of Bi3+ ions into Bi0 due to weak Bi-O bond and high etching energy. 相似文献
992.
Riguang ZhangHongyan Liu Huayan ZhengLixia Ling Zhong LiBaojun Wang 《Applied Surface Science》2011,257(11):4787-4794
The adsorption and dissociation of O2 on the perfect and oxygen-deficient Cu2O(1 1 1) surface have been systematically studied using periodic density functional calculations. Different kinds of possible modes of atomic O and molecular O2 adsorbed on the Cu2O(1 1 1) surface are identified: atomic O is found to prefer threefold 3Cu site on the perfect surface and Ovacancy site on the deficient surface, respectively. CuCUS is the most advantageous site with molecularly adsorbed O2 lying flatly over singly coordinate CuCUS-CuCSA bridge on the perfect surface. O2 adsorbed dissociatively on the deficient surface, which is the main dissociation pathway of O2, and a small quantity of molecularly adsorbed O2 has been obtained. Further, possible dissociation pathways of molecularly adsorbed O2 on the Cu2O(1 1 1) surface are explored, the reaction energies and relevant barriers show that a small quantity of molecularly adsorbed O2 dissociation into two O atoms on the deficient surface is favorable both thermodynamically and kinetically in comparison with the dissociation of O2 on the perfect surface. The calculated results suggest that the presence of oxygen vacancy exhibits a strong chemical reactivity towards the dissociation of O2 and can obviously improve the catalytic activity of Cu2O, which is in agreement with the experimental observation. 相似文献
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In this Letter, we investigate the quantum nonlocality of two-mode correlated states. We find that the pseudospin formalism [Z.B. Chen, J.W. Pan, G. Hou, Y.D. Zhang, Phys. Rev. Lett. 88 (2002) 040406] generally fails to depict the nonlocality of the states when the photon number difference between the two modes is odd. The formalism is then generalized such that the nonlocality of a two-mode correlated state can be well revealed without regard to the difference. Later we consider the nonlocality of the two-mode intelligent SU(1,1) states in the generalized formalism and compare our results with the entanglement of the corresponding states. 相似文献
998.
We introduce an instantaneous and an average instantaneous cross-correlation function to detect the temporal cross-correlations between individual stocks based on the daily data of the United States and the Chinese stock markets. The memory effect of the instantaneous cross-correlations is investigated by applying the detrended fluctuation analysis (DFA), where the DFA exponents can be partly explained by the correlation function from the common sense. Long-range memory is observed for the average instantaneous cross-correlations, and persists up to a month magnitude of timescale for the United States stock market and half a month magnitude of timescale for the Chinese stock market. In addition, multifractal nature is investigated by a multifractal detrended fluctuation analysis. 相似文献
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1000.
The effects of electromigration on copper in carbon nanotube (CNT) channels are investigated using molecular dynamics simulations. The study shows that the potential energy of copper and the resistive forces on copper are dependent on the shape of the CNT junction, and the increase in bias voltages magnifies these effects. Bias voltages affect the density of copper in the downstream CNT. The velocity of copper in the downstream CNT is relatively lower than that in the upstream CNT when the biased voltage is high. 相似文献