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31.
Aharon G. Beged-Dov Thomas A. Klein 《The Journal of the Operational Research Society》1970,21(3):311-326
This paper analyses the major problems confronted in research on management problems. That management science can neither be completely formal nor completely empirical is emphasized. The conclusion reached is that a subtle interplay between the two is essential: factual and theoretical positions which are mutually compatible must be established in the development of useful problem solving algorithms. This condition suggests that the most powerful managerial algorithms are heuristic and computer-based. 相似文献
32.
Yuri Mekler Aharon Eviatar 《Journal of Quantitative Spectroscopy & Radiative Transfer》1977,18(5):531-533
We show that the traditional interpretation of the non-detection of forbidden lines in dense natural plasmas is based on a misunderstanding. The central intensity of the line, taken to be a measure of detectability, is shown to have a maximum as a function of electron density and to be a linear function of electron density in tenuous plasmas. 相似文献
33.
A new formulation for the channel capacity problem is derived by using the duality theory of convex programming. The simple nature of this dual representation is suitable for computational purposes. The results are derived in a unified way by formulating the channel capacity problem as a special case of a general class of concave programming problems involving a generalized information measure recently introduced by Burbea and Rao [10].Research supported by National Science Foundation Grant No. ECS-8604354. 相似文献
34.
The sonolysis of an aqueous solution of Fe(CO)(5) in the presence of sodium dodecyl sulfate leads to the formation of a stable hydrosol of amorphous Fe(3)O(4) nanoparticles. The amorphicity of iron oxide nanoparticles was determined by X-ray diffraction and differential scanning calorimetry. The nanoparticles were characterized by elemental analysis, EDX, transmission electron microscopy, dynamic light scattering, Raman spectroscopy, XPS, and spot test. 相似文献
35.
The polar Kerr effect in the spin-triplet superconductor Sr2RuO4 was measured with high precision using a Sagnac interferometer with a zero-area Sagnac loop. We observed nonzero Kerr rotations as big as 65 nanorad appearing below Tc in large domains. Our results imply a broken time-reversal symmetry state in the superconducting state of Sr2RuO4, similar to 3He-A. 相似文献
36.
We describe a general scheme for solving nonconvex optimization problems, where in each iteration the nonconvex feasible set
is approximated by an inner convex approximation. The latter is defined using an upper bound on the nonconvex constraint functions.
Under appropriate conditions, a monotone convergence to a KKT point is established. The scheme is applied to truss topology
design (TTD) problems, where the nonconvex constraints are associated with bounds on displacements and stresses. It is shown
that the approximate convex problem solved at each inner iteration can be cast as a conic quadratic programming problem, hence
large scale TTD problems can be efficiently solved by the proposed method. 相似文献
37.
Abu-Much R Meridor U Frydman A Gedanken A 《The journal of physical chemistry. B》2006,110(16):8194-8203
In this paper, we report on the self-assembly formation of three-dimensional microstructures of Fe3O4 hydrosol. First, we perform new, facile, and direct fabrication of a stable hydrosol of Fe3O4 nanoparticles, based on the sonolysis of an aqueous solution of iron acetate in the presence of PVA-100,000. This is then followed by investigations of the formation of different microstructures obtained on drying a drop of the water suspension on a glass microscope substrate. The evaporation was carried out both without and in the presence of an external magnetic field. 相似文献
38.
Two model catalysts, Au/TiO2/C (S) (sonochemically derived) and Au/TiO2/C (M) (microwave derived), were produced by employing ultrasound irradiation and microwave irradiation, respectively. The deposition of gold colloids onto the support powders, TiO2/C, was accomplished by using a solvated metal atom impregnation (SMAI) method. The SMAI technique provides highly-dispersed gold particles on the TiO2/C support. The catalytic performance of Au based catalysts 1 wt% Au-TiO2/C (S) and 1 wt%Au-TiO2(M)/C (M) have been tested for the oxidation of CO in the temperature range of 0-300 degrees C and compared to that of 1 wt% Au-TiO2 (Degussa-P25). A boost in the conversion of CO was observed for the sonochemically-derived catalyst, Au/TiO2/C (S), at low temperature. Hence, the reactivity order found for CO oxidation is (Au/TiO2/C (S)>Au/TiO2 (P25)>Au/TiO2/C (M)). 相似文献
39.
A.I. Shames E. Rozenberg Ya.M. Mukovskii E. Sominski A. Gedanken 《Journal of magnetism and magnetic materials》2008,320(14):e8-e11
Electron magnetic resonance (EMR) was studied on crystalline bulk and nanometer-sized samples of the same La0.7Ca0.3MnO3 manganite compound aiming to compare their magnetic homogeneities. The results obtained show that single-crystalline bulk sample is less homogeneous than the nanocrystalline one. Except for higher homogeneity, the nanometer-sized sample also demonstrates a weaker magnetic anisotropy. As a result, well-pronounced coexistence of different magnetic phases (coexistence of ferromagnetic and paramagnetic resonance signals) is observed in the bulk sample, while it is absent in the nanocrystalline one. It is suggested that such strong difference is directly connected to the difference in structural state of the samples. 相似文献
40.
Aharon Razon 《manuscripta mathematica》1997,94(1):531-542
We construct an abundance of Hilbertian domains: LetK be an abelian extension of ? such that {ord(a)|a εG(K/?)} is unbounded, let ? K be its ring of integers, and lete ≥ 2 be an integer. Then, for almost all σ εG (?) e , each ring between ? K andK · (σ) is Hilbertian. 相似文献