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71.
“Optimization of aircraft maintenance/support infrastructure using genetic algorithms—level of repair analysis” 总被引:4,自引:0,他引:4
Level of repair analysis (LORA) is an approach used during the design stage of complex equipment for analysis of the cost
effectiveness of competing maintenance strategies. LORA is carried as a part of the life cycle cost and cost of ownership
analysis and plays a significant role in minimizing the life cycle cost and cost of ownership of the capital equipment. Since
many purchasing decisions of complex equipment are based on cost of ownership, it has become essential to carry out LORA to
compete in the market. In this paper, we develop a mathematical model for LORA and propose a solution methodology based on
genetic algorithms. The concept is illustrated using a hypothetical aircraft engine. 相似文献
72.
Th. Friedrich I. Kath A. Moroianu U. Semmelmann 《Journal of Geometry and Physics》1997,23(3-4):259-286
A nearly parallel G2-structure on a seven-dimensional Riemannian manifold is equivalent to a spin structure with a Killing spinor. We prove general results about the automorphism group of such structures and we construct new examples. We classify all nearly parallel G2-manifolds with large symmetry group and in particular all homogeneous nearly parallel G2-structures. 相似文献
73.
A. U. Klimyk 《Ukrainian Mathematical Journal》1992,44(7):801-812
Kravchuk polynomials of a discrete variable and different types of Kravchuk q-polynomials are determined. The importance of these polynomials for the theory of representations of Lie and Chevalley groups and the theory of symmetric and quantum groups is shown. The article presents a survey of the contemporary results in these areas.Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 44, No. 7, pp. 888–901, July, 1992. 相似文献
74.
P. -M. Binder 《Journal of statistical physics》1992,67(3-4):827-832
Average first-passage times for a single-variable stochastic model with a critical fixed point at the origin are computed by exact enumeration. The numerical measurements show excellent agreement with analytical results. The scaling function approaches the predicted asymptotic dependence. 相似文献
75.
The new olefinic substituted aminodisilanes, which are obtained from the reaction of organometallic reagents with aminochlorodisilanes, are converted into the chlorodisilanes by equilibration reactions or treatment with HCI. The resulting olefinic functionalized disilanes are identified by means of 29Si, 13C, 1H NMR and GC MS measurements. 相似文献
76.
We show that if a polynomial filled Julia set has empty interior, then it is computable. 相似文献
77.
78.
R. López-Martens J. Mauritsson P. Johnsson K. Varjú A. L’Huillier W. Kornelis J. Biegert U. Keller M. Gaarde K. Schafer 《Applied physics. B, Lasers and optics》2004,78(7-8):835-840
We characterize the temporal structure of high-order harmonic radiation on both the femtosecond and attosecond time scales. The harmonic emission is characterized by mixed-color two-photon ionization with an infrared femtosecond laser using a Mach–Zehnder interferometer where both pump and probe arms travel completely separate paths. In a first experiment, we measure the duration and chirp of individual harmonics. In a second experiment, we resolve, for the first time with this type of setup, the attosecond beating of several harmonics generated under conditions similar to the first experiment. We suggest that the results of both measurements can be combined to determine the full attosecond time structure of the harmonic emission. PACS 32.80.Rm; 42.65.Ky 相似文献
79.
80.
We have studied by ESR and ENDOR spectroscopy the free radicals produced in γ-irradiated inclusion compound formed between the ketone 10-nonadecanone and urea. Only one type of long lived radical is formed by the removal of an α-proton from the ketone. The hyperfine (hf) coupling constants of the α- and β-protons of the radicals have been measured by ESR at different temperatures in the range 110–292 K and at different orientations of the crystals. The hf coupling of the γ-protons of the radical and of the urea protons have been studied by ENDOR. The temperature and angular dependences of the coupling constants have been analyzed in terms of the internal and overall motions of the radical inside the hexagonal channels formed by the urea molecules. It has been found that the radical cannot perform complete reorientations around the long molecular axis, but it undergoes restricted rotational diffusion. This process is explained by assuming a coupling between the rotational and translational degrees of freedom of the radical inside the urea channels. 相似文献