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901.
902.
Michael S. Roddy 《Order》1994,11(1):1-9
Theretracts (idempotent, isotone self-maps) of an ordered set are naturally ordered as functions. In this note we characterize the possible ways that one retract can cover another one. This gives some insight into the structure of the ordered set of retracts and leads to a natural generalization of the core of an ordered set.Supported by NSERC Operating Grant 41702. 相似文献
903.
S. E. Kholodovskii 《Journal of Applied Mechanics and Technical Physics》1991,32(6):931-933
Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, No. 6, pp. 119–122, November–December, 1991. 相似文献
904.
905.
906.
Let M be a symplectic manifold with a Hamiltonian circle action with isolated fixed points. We prove that σ (M) = b0(M) − b2(M) + b4(M) − b6(M) + … where σ (M) is the signature of M and bi(M) is the ith Betti number of M. 相似文献
907.
P. I. H. Bastiaens S. G. Mayhew E. M. O'Naulláin A. van Hoek A. J. W. G. Visser 《Journal of fluorescence》1991,1(2):95-103
Both a mode-locked argon-ion laser and synchrotron radiation were used as excitation sources to obtain time-resolved polarized fluorescence of the two FAD cofactors in electron transferring flavoprotein fromMegasphaera elsdenii. Red-edge excited and blue-edge detected fluorescence anisotropy decay curves did not contain a fast relaxation process which was observed upon mainband excitation and detection. This relaxation was assigned to homo-energy transfer between the two FAD cofactors. Failure of energy transfer as observed with edge spectroscopy on this protein excludes restricted reorientational motion of the flavins as a possible mechanism of depolarization. From the global analysis of the fluorescence anisotropy decay surface obtained at multiple excitation and detection wavelengths, the distance between and the relative orientation of the flavins could be estimated. The methodology described has general applicability in other multichromophoric biopolymers and has the potential to acquire accurate geometrical parameters in these systems. 相似文献
908.
The diffusion of Ni on a Si (111) surface is investigated by LEED and Auger electron spectroscopy. It is found that, in contrast
to the process on the initially clean Si (111)−7×7 surface, on Si (111) surfaces with submonolayer Co coverages the nature
of the Ni transport mechanism changes at a temperature of about 750 °C, and the Ni surface diffusion coefficients increase
sharply below this temperature.
Pis’ma Zh. éksp. Teor. Fiz. 66, No. 9, 611–614 (10 November 1997) 相似文献
909.
A. S. Il'inskii S. V. Trubnikov N. A. Fedoseeva 《Computational Mathematics and Modeling》1994,5(3):195-202
Translated from Matematicheskie Modeli i Optimizatsiya Vychislitel'nykh Algoritmov, pp. 131–143, 1993. 相似文献
910.
A well-known problem of prediction in linear regression models is to find a confidence interval for the random value of the dependent variable when the values of the independent variables are given. Such a situation may arise in economic quality control models when the independent variables are costly inputs and the dependent variable is some measure of quality or production. In such a circumstance, an important control objective may be to find values for the inputs that will maximize the lower limit of the prediction confidence interval for a fixed budget, or alternatively, to minimize the cost of the inputs for a fixed lower limit of the confidence interval. In this paper, we shall show that global optima can be found using known algorithms. The special case of simple linear regression is discussed and an illustrative example is provided. 相似文献