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871.
Yu. F. Popov A. M. Kadomtseva G. P. Vorob’ev S. S. Krotov K. I. Kamilov M. M. Lukina 《Physics of the Solid State》2003,45(11):2155-2159
Complex studies of the magnetic, magnetoelectric, and magnetoelastic properties of GdMn2O5 single crystals in strong pulsed magnetic fields are carried out in order to obtain additional indirect information on the character of the rare-earth and manganese spin ordering. It is shown that magnetic ordering of Gd3+ spins affects the manganese sublattice spin orientation and initiates new magnetic phase transitions. The observed magnetoelectric properties of the GdMn2O5 system are interpreted in terms of the theory of phase transitions. 相似文献
872.
Magnetization reversal processes by a switching field in single-domain nano-sized magnetic particles in the presence of a small transverse non-static bias field are studied. Applying an oscillating bias field instead of a static field, the reversal time becomes much shorter when the switching field is slightly stronger than the effective anisotropy field. A pulsed bias field of a suitably chosen duration in the nanosecond scale is found to induce a rapid switching, even when the switching field is smaller than the anisotropy field. The dependence of the reversal time on the frequency of an oscillating bias field and the duration of a pulsed bias field are studied. The present work thus complement the earlier studies on switching in the presence of a static bias field. 相似文献
873.
The electrocatalytic oxidation of 2-propanol was investigated using on line differential electrochemical mass spectrometry (DEMS) on electrodeposited Pt and an arrange of bimetallics: Pt0.84Rh0.16, Pt0.70Rh0.30, Pt0.55Rh0.45. It has been observed that the Pt0.84Rh0.16 bimetallic electrode presented the best catalytic activity for 2-propanol electrochemical oxidation. Since 2-propanol is a secondary alcohol, only acetone and CO2 are produced. The total yield of CO2 and acetone has been determined from the DEMS measurements. It is found that acetone is the major product, as reported before for other electrodes. The acetone and CO2 yield depends on the electrode composition. High amount of rhodium in the electrode composition strongly diminish the reaction rate as indicated by the decrease of both the acetone and CO2 yield. However, acetone inhibition is much more intense. The only bimetallic electrode that presents considerable mass spectroscopy signals intensity for CO2 and acetone is the Pt0.84Rh0.16 electrode. This electrode shows a slight increase in CO2 selectivity, compared to the other electrodes studied in this work. Only very low coverages of stable adsorbates were present during the reaction. Two and one carbon adsorbate were observed for all the electrodes. Three carbon adsorbates were detected only for the Pt0.84Rh0.16 electrode. Therefore, acetone production does not require a stable adsorbate. 相似文献
874.
Translated from Matematicheskie Zametki, Vol. 57, No. 3, pp. 338–349, March, 1995. 相似文献
875.
Yu. I. Ryabukhin A. Yu. Eliseeva K. F. Suzdalev 《Chemistry of Heterocyclic Compounds》1992,28(2):236-237
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 280–281, February, 1992. 相似文献
876.
E. A. Davis A. Singh S. F. J. Cox S. R. Kreitzman T. L. Estle B. Hitti R. L. Lichti R. DuVarney 《Hyperfine Interactions》1994,86(1):705-710
Studies of the muonium fractions in the amorphous oxide a-SiO have been carried out by RF resonance at TRIUMF, Canada and LF repolarization techniques at RAL, U.K. The resonance measurements confirm the presence of the interstitial Mu centre in this intermediate oxide of silicon. Analysis of the data gathered at RAL, using a recently-developed fitting technique, reveals that the Mu* state is present here as well, but with lower relative fractions than in a-Si. However, as in the latter material, but in contrast to c-Si, this bond-centre species appears to be stable up to room temperature. 相似文献
877.
878.
Bruno Crosignani 《Fiber and Integrated Optics》1992,11(3):235-252
The basic differential equations necessary to represent nonlinear propagation of short and ultrashort optical pulses in dielectric waveguides are derived. After introducing fundamental and higher-order soliton solutions of the nonlinear Schroedinger equations, the possibilities of realizing soliton-based communication systems are discussed. Higher-order nonlinear effects associated with selj-Raman gain and optical amplification in connection with the use of active fibers are also described. 相似文献
879.
Eu3+ in ca. 10 wt% europium-exchanged Y-zeolite is partially reduced by treatment in hydrogen at 600°C to Eu2+. The reduction of Eu3+ is more readily achieved in Y-zeolite than in europium(III) oxide. The discrepancy in the extent of reduction as revealed by151Eu Mössbauer spectroscopy and near edge X-ray absorption fine structure (XANES) is associated with any difference in the recoil free fractions of Eu2+ and Eu3+ which may exist at 298 K and the enhanced sensitivity of the XANES to changes in the europium oxidation state. 相似文献
880.
B.J. Stoyanov R.A. Farrell J.F. Bird 《Journal of Computational and Applied Mathematics》1994,50(1-3):533-543
Asymptotic expansions of certain finite and infinite integrals involving products of two Bessel functions of the first kind are obtained by using the generalized hypergeometric and Meijer functions. The Bessel functions involved are of arbitrary (generally different) orders, but of the same argument containing a parameter which tends to infinity. These types of integrals arise in various contexts, including wave scattering and crystallography, and are of general mathematical interest being related to the Riemann—Liouville and Hankel integrals. The results complete the asymptotic expansions derived previously by two different methods — a straightforward approach and the Mellin-transform technique. These asymptotic expansions supply practical algorithms for computing the integrals. The leading terms explicitly provide valuable analytical insight into the high-frequency behavior of the solutions to the wave-scattering problems. 相似文献