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791.
A theoretical non-contact atomic force microscope (nc-AFM) image is simulated for an individual C60 molecule adsorbed on the clean Si(0 0 1) surface. The ability to identify the intramolecular features of the molecule though nc-AFM imaging would allow many of the different configurations the molecule may take when adsorbed, to be identified. This would be an important preliminary step in the manipulation of the molecule along the surface, as the initial configuration that the molecule is in will affect the periodicity of the tip trajectory during the manipulation event (see D.L. Keeling et al., Phys. Rev. Lett. 94 (2005) #146104). Presented in this paper are simulated images and force curves above important sites for key stable configurations of the C60 molecule. It is shown that in principle it is possible to distinguish between the different configurations of the molecule using nc-AFM. An ab initio DFT method was used to accurately describe the chemical interaction between the adsorbate and the Si tip, which has a single dangling bond at its apex. 相似文献
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794.
Triple exposure holographic interferometry provides knowledge of the displacement vector. Between the first two exposures the object is displaced by a calibrated amount, and before the last exposure it is translated by an unknown amount. 相似文献
795.
This article serves as an introduction to the focus issue on optical solitons. After a short review of the history of solitons and the field of integrable systems, a brief overview of the development of nonlinear optics and optical solitons is provided. Next, the various contributions to this focus issue are presented, and a few separate remarks are devoted to optical communications, where solitons promise to play a decisive role in the next generation of commercial systems. (c) 2000 American Institute of Physics. 相似文献
796.
S.B. Lev V.I. Sugakov G.V. Vertsimakha 《Physica E: Low-dimensional Systems and Nanostructures》2008,40(9):2899-2903
Transitions between direct and indirect excitons with change of magnetic field in double quantum well heterostructure Cd1−xMgxTe/Cd1−yMgyTe/Cd1−xMgxTe/Cd1−zMnzTe/Cd1−xMgxTe in external magnetic field are studied. The structure contains diluted magnetic semiconductor (Cd,Mn)Te layer that forms magnetic quantum well with the depth depending on the magnetic field intensity. Above some magnetic field the indirect exciton becomes the lowest excited state of the system. The indirect exciton lifetime exceeds by several orders of magnitude of the direct exciton one. The range of quantum well widths for which the indirect exciton is the exciton lowest state was estimated for the proposed system. 相似文献
797.
Lev S. Ruzer 《Journal of nanoparticle research》2008,10(5):761-766
A number of studies on the exposure of nanometer aerosols have indicated that health effects associated with low-solubility
inhaled particles in the range of 1–100 nm may be more appropriately associated with particulate surface area than mass concentration.
Such data on correlation between number, surface area and mass concentration are needed for exposure investigations, but the
means for measuring aerosol surface area are not readily available. In this paper we propose a method for particle surface
area assessment based on a new approach, deposition of the “unattached fraction of radon progeny” onto nanometer aerosols.
The proposed approach represents a synthesis of:
(1) Derived direct analytical correlation between the “unattached fraction” of radon progeny and surface area particle concentration
in the range of 1–100 nm particle diameter;
(2) Experimental data on correlation between the unattached fraction of radon progeny and particle surface area for particles
with diameter in the range of 44 nm–2.1 μm. 相似文献
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800.
Lev Kapitanski 《偏微分方程通讯》2013,38(7-8):1303-1323
Abstract The asymptotic behavior of eigenvalues of an elliptic operator with a divergence form is discussed. The coefficients of the operator are discontinuous through a boundary of a subdomain and degenerate to zero on the subdomain when a parameter tends to zero. We will prove that the eigenvalues approach eigenvalues of the Laplacian on the subdomain or on the complement. We will obtain precise asymptotic behavior of their convergence. 相似文献