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61.
62.
Auger spectroscopy has been used to investigate the interactions of oxygen and nitrogen with both the (100) face niobium and with polycrystalline niobium. Sticking coefficients for both gases have been determined as a function of coverage. A temperature and concentration ependent segregation of oxygen at the surface has been observed even under conditions where the solid solubility of the bulk was not exceeded. A model to describe this segregation has been developed and extended to explain discrepancies in earlier investigations f the reaction of oxygen with niobium. 相似文献
63.
The density of states for the Ni-Cu alloy system has been calculated as a function of concentration by the supercell method. This method takes into account inter-site interactions in contrast with current effective medium or single site theories. We show that the method is practical for the study of disordered systems. Comparison is made with previous work as well as with photoemission data. 相似文献
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66.
Harold Widom 《Integral Equations and Operator Theory》1978,1(3):415-443
Pseudodifferential operator techniques are employed to obtain higher-order spectral asymptotic results for integral operators on hypersurfaces in Euclidean space.Supported by a grant from the National Science Foundation. 相似文献
67.
Harold Jones 《Applied Physics A: Materials Science & Processing》1977,14(2):169-173
The design and use of two wide-band microwave cells suitable for double resonance experiments within the resonator of a cw
CO2-laser are described. The high sensitivity of the intracavity arrangement allowed very strong double-resonance and two-photon
transition signals to be observed with high microwave-frequency scan-rates (1 GHz/min), and low microwave pumping powers (≦10mW/cm2). Both cells were used over a range 15 to 63 GHz, with transmission and VSWR measurements made over the range 18 to 26.5
GHz. 相似文献
68.
69.
Andrew T. Zander Myron H. Miller 《Spectrochimica Acta Part B: Atomic Spectroscopy》1985,40(8):1023-1037
Electron densities are measured in the high current, analytical and intervening zones of a DCP whose operating parameters are systematically varied. Detailed Ne distribution profiles are obtained for various sleeve flow, nebulizer flow, arc current and matrix concentration regimes. Flowing argon is found to establish a thermal pinch in the high current zone and to steepen gradients in plasmas employed for spectrochemical analysis. The distinctive electron density distributions in the DCP are more sensitive to modulation of gas flow variables than to changes in arc current. Magnetic pressure has no discernible role in pinch formation. Electron densities in spectroscopic regions are minimally affected by easily ionized or other matrix constituents at usual analytical concentrations. 相似文献
70.
The knapsack problem, maximize Σmi = 1cixi when Σmi = 1aixi?b for integers xi?0, can be solved by the classical step-off algorithm. The algorithm develops a series of feasible solutions with ever-increasing objective values. We make a change in the problem so that the step-off algorithm produces a series of solutions of not necessarily increasing objective values. A point is reached when no better solutions can be found and the calculation is stopped. 相似文献