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981.
In this paper three Banach spacesA
0(),A
andA
1() of functions holomorphic in the unit ballB of
n
are defined. We exhibit bounded projections fromC
0(B) ontoA
0(), fromL
1(B) ontoA
1(), and fromL(B) ontoA(). Using these projections, we show thatA
0()* A
1() andA
1()* A().Supported in part by the National Natural Science Foundation of China. 相似文献
982.
John Doyle 《The Journal of the Operational Research Society》1994,45(2):203-213
Following a critique of existing algorithms, an algorithm is presented which will re-organize a 2-way data table to bring like rows together, and like columns together. Extensions of the method are described, and justified, to accommodate distances measured in modular arithmetic, and with bipolar columns/rows, as in repertory grid analysis. One value of the algorithms is that the user can see relationships in the tables without the data in the cells themselves ever having been transformed. Thus, users will continue to feel they own their data. 相似文献
983.
This paper deals with the GI x /G/c queueing system in a steady state. We refine a diffusion approximation method incorporating the constraint of traffic conservation for general queueing systems. An approximate expression for the distribution of the number of customers is obtained. Numerical results are presented to show that the refined model provides improved performance. 相似文献
984.
985.
Mössbauer measurements in a-(Fe0.765Mn0.235)78Sn2Si6B14 have been performed with57Fe and119Sn. Both hyperfine fields show a kink near 70 K, indicating a freezing of the transverse spins. The ratio of the two hyperfine fields contains information about the correlation of the transverse spins. The ratioB
hf(Sn)/B
hf(Fe) stays constant aboveT
xy
and rises belowT
xy
. This indicates an alignment of the transverse spins on a local scale, as was also found inAuFe and a-FeZr. 相似文献
986.
Arcadiy V. Krasheninnikov Konstantin E. Kon’kov Leonid A. Openov Vladimir F. Elesin 《Czechoslovak Journal of Physics》1996,46(3):1197-1198
The effect of ion irradiation on the superconducting transition temperatureT c and resistivityρ ab (T) of YBa2Cu3O7-x films with different oxygen content (initial temperatureT c0≈90 K and 60 K) is studied experimentally. The dependenciesT c /T c0 on residual resistivityρ o are obtained in very wide range 0.2<T c /T c0 <1 andρ o μΩ·cm. The critical values ofρ o , corresponding to the vanishing of superconductivity, are found to be an order of magnitude larger then those predicted by theory ford-wave pairing. At 0.5÷0.6<T c /T c0<1 the experimental data are in close agreement with theoretical dependencies, obtained for the anisotropics-wave superconductor within the BCS-framework. 相似文献
987.
N. E. Hussey J. R. Cooper Chen Changkang J. W. Hodby 《Czechoslovak Journal of Physics》1996,46(3):1201-1202
Low-field magnetizationM(H) measurements can be used to probe the nature of the screening currents and the interlayer coupling in high-T c cuprates. Here we compare theM(H) behaviour of single crystals of Bi2Sr2CaCu2O8 and fully oxygenated and oxygen reduced YBa2Cu3O7??. In YBa2Cu3O7, theM(H) behaviour is consistent with anisotropic 3D superconductivity whilst in Bi2Sr2CaCu2O8, the surface screening currents are strongly affected by the presence of vortices, implying that the CuO2 planes are coupled via a weak Josephson interaction. In oxygen-deficient YBa2Cu3O6.7 (T c =63K), theM(H) behaviour at low temperatures is similar to that found for Bi2Sr2CaCu2O8, implying that the removal of oxygen from the chains has resulted in a dimensional crossover of the superconducting state in YBa2Cu3O7??. As the temperature approachesT c , the 3D behaviour is eventually restored as thec-axis coherence length ξ c becomes comparable with the interlayer spacingd. 相似文献
988.
Tshakane Tshepe Johan F. Prins Michael J. R. Hoch 《Czechoslovak Journal of Physics》1996,46(5):2439-2440
We have investigated low-temperature electrical transport mechanisms in the surface layer of a type IIa diamond which has been heavily implanted with boron-ions at low temperatures and then annealed at high temperatures. The boron atoms occupy substitutional sites giving rise to a heavily doped wide-bandgap semiconductor. The dc-conductivity results suggest that for the maximum boron doping that has been achieved, the diamond sample is close to the insulator-metal transition. A model to account for the observed increase in activated boron centres with ion dose is presented. On the insulating side of the transition, the data are interpreted in terms of variable-range hopping laws. 相似文献
989.
Katsunori Wakabayashi Mitsutaka Fujita Koichi Kusakabe Kyoka Nakada 《Czechoslovak Journal of Physics》1996,46(4):1865-1866
Anoble mechanism of spin polarization is proposed for finite graphite sheet with edge. For graphite ribbon with zigzag edge, there appear peculiar ‘edge states’. These localized states comprise nearly flat band at the Fermi level, which easily causes magnetic instability. Magnetic structure is suggested from Hartree-Fock analysis of the Hubbard model, where huge magnetic moments are induced at around both of edges by weak HubbardU and are coupled antiferromagnetically with each other. 相似文献
990.
LetK be an algebraically closed field withp:=char (K)>0 andX a bielliptic curve over Spec(K) with genus≥6 and such that the canonical model ofX is ordinary. In this paper we determine all the possible gap sequences of Weierstrass points on such curves. 相似文献