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131.
132.
J. Balogh D. Kaptás L. F. Kiss T. Kemény L. Bujdosó I. Vincze 《Hyperfine Interactions》2006,169(1-3):1343-1347
Magnetic multilayers of 57Fe with nominal thickness, T
nom, between 0.4 and 1.0 nm separated by 3.0 nm Al spacer layers were prepared by alternate deposition of the constituents in
high vacuum. The samples were investigated at 4.2 K in external magnetic field. A fraction of Fe atoms corresponding to about
0.3 nm equivalent Fe-thickness was found to mix into the Al spacer. The extremely strong magnetic anisotropy observed for
T
nom < 0.8 nm is attributed to Fe layers of approximately two atomic planes thick. The anisotropy decreases considerably after
the building up of the third Fe atomic layer starts at T
nom = 0.8 nm, but full saturation was not achieved even for T
nom = 1 nm and 3 T magnetic field applied perpendicularly to the sample plane. 相似文献
133.
B. E. López M. A. Rodriguez S. L. A. Fucugauchi 《Journal of Radioanalytical and Nuclear Chemistry》1993,175(4):273-280
It has been established that the coexistence of chemical species structurally different from cerium, is a direct consequence of the time taken for its preparation. Its practical applications, within the scope of purifying uranium, may constitute the most important technological aspect in the process of ionic exchange, to separate141Ce from uranium. 相似文献
134.
Let F denote a family of pairwise disjoint convex sets in the plane. F is said to be in convex position if none of its members is contained in the convex hull of the union of the others. For any fixed k≥ 3 , we estimate P
k
(n) , the maximum size of a family F with the property that any k members of F are in convex position, but no n are. In particular, for k=3 , we improve the triply exponential upper bound of T. Bisztriczky and G. Fejes Tóth by showing that P
3
(n) < 16
n
.
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<onlinepub>26 June, 1998
<editor>Editors-in-Chief: &lsilt;a href=../edboard.html#chiefs&lsigt;Jacob E. Goodman, Richard Pollack&lsilt;/a&lsigt;
<pdfname>19n3p437.pdf
<pdfexist>yes
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</lsiheader>
Received March 27, 1997, and in revised form July 10, 1997. 相似文献
135.
M. A. Morón C. Romero F. R. Ruiz del Portal 《Journal of Optimization Theory and Applications》1996,91(3):643-649
The purpose of this paper is to seek utility functions satisfying a weak condition which guarantees that the utility optimum always belongs to the compromise set. This set is a special subset of the attainable or feasible set, which is generated through the application of the well-known operational research approach called compromise programming. It is shown that there are large families of utility functions satisfying this condition, thus reinforcing the value of compromise programming as a good surrogate of the traditional utility optimum.Thanks are due to the reviewers for their helpful suggestions. The English editing by Ms. Christine Méndez is appreciated. The authors have been supported by the Comisión Interministerial de Ciencia y Tecnología (CICYT), Madrid, Spain. 相似文献
136.
János Komlós 《Order》1990,7(2):107-113
Using Ramsey theory, we establish the following pigeon-hole type principle: From a large number of random variables (functions, vectors, etc.) one can always select two, X and Y, such that P(X < Y) 1/2. We apply the principle for a poset problem. 相似文献
137.
J. Casahorrán J. G. Esteve A. Tarancón 《International Journal of Theoretical Physics》1990,29(12):1285-1297
We consider bidimensional scalar models including kink solutions
k
(x). Using the hidden supersymmetric properties of the Dirac equation, we describe a general method to find normalizable fermionic zero modes. In particular, we apply the technique to a (
6)1+1 model. Going to the one-loop order of the effective potential, the emergence of a radiative kink provides an interesting scalar background in order to discuss the Dirac equation. 相似文献
138.
Novel mixed valence states have been obtained by the treatment of cobaltous ferrocyanides (Co+2FeII) and ferricyanides (Co+2FeIII) in an ozone flow. The CN stretching bands occur at 2085 cm–1 for Co+2FeII and at 2160 cm–1 for Co+2FeIII. After the ozonization process of Co+2FeII, an intense band approximately at 2125 cm–1 is detected. This intermediate band must correspond to a mixed valence state of the type: FeII–CN–Co2+–NC–FeIII Mössbauer spectra recorded in situ during the ozonization of Co+2FeII show the presence of two components: a doublet with isomer shift and quadrupole splitting values close to the cobalti ferricyanide and a very broad line for the mixed valence state. From the Mössbauer and infrared spectra of the aged samples of the Co+2FeII after ozonization, a relaxation process to the initial state of the samples is observed but the mixed valence state is stable. 相似文献
139.
140.
The title compound (C14H8N2O7,M
r
=306.2) crystallizes in the orthorhombic space group Pbca witha=6.962(1).b=24.688(1), andc=15.890(1)Å,V=2731.0 Å3,D
x
=1.489 g·cm–3 forZ=8,=0.98 mm–1,F(000)=1296,T=293 K. FinalR=0.053 for 1873 observed reflections. The structure was solved by direct methods. Approximately planar molecules lie perpendicular to the [100] direction and show partial stacking. The structure is the first example of a symmetric anhydride which does not retain the symmetry in the crystal state. The two independent nitro groups twist out of the ring planes by 10.5 and 14.8°, respectively. 相似文献