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Structure and magnetic properties of the Zr1−xMnxCo2+δ alloys were studied for 0 x <0.7, δ=0, 0.45. The cubic C15 Laves phase structure shows Mn solubility up to x≈0.4. The other Laves phase with the hexagonal C36 structure found for x0.5 apparently has a small region of Mn solubility in the vicinity of Zr0.4Mn0.6Co2. Though the parent Mn-free compounds are known to be paramagnetic, the Mn-substituted alloys show ferromagnetic behavior with the Curie temperatures up to 625 K and the room-temperature saturation magnetization of about 100 emu/g. The onset of ferromagnetism with the Mn substitution for Zr may be caused by polarization of itinerant 3d electrons, like it was earlier supposed for the off-stoichiometric ZrCo2+δ. The universal composition dependencies of the intrinsic magnetic properties for different δ can be obtained, if plotted against the amount of zirconium atoms missing in its sublattice. The room-temperature anisotropy with the noticeable anisotropy field of 24 kOe and the 1 1 0 easy magnetization direction laying in a basal plane was found in the hexagonal Zr0.5Mn0.5Co2. 相似文献
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M. Boazi J. Gabay S. Devir C. Shenberg 《Journal of Radioanalytical and Nuclear Chemistry》1978,45(2):395-406
Aerosol samples from urban, industrial and traffic areas were collected and analyzed for various elements. The correlation
between the multielement content of the samples and their sources was studied. It was found necessary to anlayze samples before
and after ashing because, while ashing improves the peak-to-background ratio, volatile elements may be lost. Samples collected
at heights of 1.5 and 15 m were found to have the same elemental composition. Samples collected on consecutive filters showed
sharp elemental fractionation An example of source identification is given for a high traffic area as compared with an area
in which a large bromine plant is located. In both cases different Pb∶Br ratios were observed, with high bromine concentration
in the latter. The analytical method used was based on the detection of characteristic K and L X-rays induced by a241Am-I source-target assembly. 相似文献
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Michaël Gabay Nadia Brauner Vladimir Kotov 《4OR: A Quarterly Journal of Operations Research》2017,15(2):183-199
We use game theory techniques to automatically compute improved lower bounds on the competitive ratio for the bin stretching problem. Using these techniques, we improve the best lower bound for this problem to 19/14. We explain the technique and show that it can be generalized to compute lower bounds for any online or semi-online packing or scheduling problem. 相似文献
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Muriel Ney-Nifle Marc Gabay 《Physica C: Superconductivity and its Applications》1995,250(3-4):349-360
We study the thermal fluctuations of anisotropic order parameters (OP) in layered superconductors. In particular, for copper oxides and a d-wave OP, we present some experimental consequences of fluctuations in the direction normal to the layers. It is shown that the c-axis penetration depth λc can have a “disorder-like” quadratic temperature dependence at low temperature. The fluctuations are analyzed in the framework of a Lawrence-Doniach model with an isotropic Fermi surface. Anisotropies pin the orientation of the OP to the crystallographic axes of the lattice. Then we study an extended t-J model that fits Fermi surface data of bilayers YBCO and BSCCO. This leads to a d-wave OP with two possible orientations and, including the thermal fluctuations, yields the announced temperature dependence of λc. Furthermore a reservoir layer is introduced. It implies a finite density of states at the Fermi energy which is successfully compared to conductance and specific heat measurements. 相似文献
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J. Tenenbaum I. Smilanski S. Gabay L.A. Levin G. Erez S. Lavi 《Optics Communications》1980,32(3):473-477
The structure of the 510.6 and 578.2 nm copper laser lines were calculated and measured as a function of cooper density and buffer gas pressure. The line shapes were consistent with the calculations only near the oscillation threshold. The buffer gas pressure data indicate that the pressure broadening coefficient is very small for our experimental conditions. 相似文献
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A.M. Gabay M. Marinescu-Jasinski C.N. Chinnasamy J.F. Liu G.C. Hadjipanayis 《Journal of magnetism and magnetic materials》2012
Processes of high-energy ball milling of SmCo5 alloys were compared for three single-liquid environments without using additional surfactants. Both coarsely grained as-cast and nanocrystalline pre-milled SmCo5 precursors showed tendency toward formation of thin flakes if milled in polar liquids (acetone and ethanol) in a marked contrast to milling in non-polar heptane. CaF2 dielectric powder added prior to milling in the polar liquids tends to become attached on the flake surfaces. Milling in heptane in the presence of CaF2 produces flake-like SmCo5 particles which with increasing the milling time are found to incorporate an increasing amount of CaF2. The SmCo5—5 wt% CaF2 mixtures milled for the optimum time in both the polar and non-polar liquids were successfully hot-pressed into laminated composite magnets having intrinsic coercivity of 25–30 kOe, maximum energy product of approximately 6.5 MG Oe and electrical resistivity of 500–600 μΩ cm, which is more than 7 times the resistivity of conventional Sm–Co magnets. 相似文献
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M. Benakli M. Gabay W.M. Saslow 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,1(2):197-204
Boundary conditions strongly affect the results of numerical computations for finite size inhomogeneous or incommensurate
structures. We present a method which allows to deal with this problem, both for ground state and for critical properties:
it combines fluctuating boundary conditions and specific histogram techniques. Our approach concerns classical systems possessing
a continuous symmetry as well as quantum systems. In particular, current-current correlation functions, which probe large
scale coherence of the states, can be accurately evaluated. We illustrate our method on a frustrated two dimensional XY model.
Received: 9 September 1997 / Revised: 17 October 1997 / Accepted: 3 November 1997 相似文献
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