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131.
The aim of this contribution is to study lanthanum containing fullerenes produced and treated under different conditions. The work was done using solid soot extract giving poorly resolved ESR spectra or separated lanthanofullerenes in solution showing well resolved ESR spectra. ESR experiments in connection with the mass spectrometry give information on the electronic states due to the electron transfer from the endohedral metal to the fullerene cage and the influence of oxygen on endohedral lanthanofullerene. The analysis of ESR spectra indicates the presence of up to nine octets of lanthanum containing fullerenes. These species have different stabilities. Furthermore, a very narrow single ESR line in the lanthanofullerene spectrum was detected having a linewidth ΔB=0.008 mT and ag-factor 2.0025. The electron transfer to the endohedral La@C82 molecule studied by voltammetry and electrochemicalin situ ESR experiments is described. The interaction of the lanthanofullerene with oxygen in solution is also studied. In different solvents the influence of oxygen on line broadening in the ESR spectra of La@C82 was observed. 相似文献
132.
H. Günther M. Foerste M. Kunze G. zu Putlitz U. von Stein 《Zeitschrift für Physik B Condensed Matter》1996,100(4):613-617
We review the previous conclusion [J.Y. Ryu, Y.C. Chung and S.D. Choi, Phys. Rev. B 32, 7769 (1984)] that the trace property Tr(ABC) = Tr(CAB) leads to two different cyclotron transition absorption formulae in the electron-phonon systems in the lowest order approximation. The pictorial expression and the calculated linewidths in Ge and Si show that the socalled EWC scheme is more seeming than the socalled MWC scheme. The difference is expected to disappear if we take into account all the higher order perturbation terms or start with the many body formalism in the complete scheme. 相似文献
133.
H. Fawcett S. Barlag H. Becker E. Belau T. Böhringer M. Bosman V. Castillo V. Chabaud D. Bucholz C. Damerell C. Daum G. De Rijk H. Dietl S. Gill A. Gillman R. Gilmore T. Gooch P. Gras Z. Hajduk E. Higon B. Hyams D. Kelsey J. Kemmer R. Klanner U. Kötz S. Kwan B. Lücking G. Lütjens G. Lutz J. Malos W. Männer E. Neugebauer H. Palka M. Pepé G. Polok J. Richardson M. Rozanska K. Rybicki H. Seebrunner U. Stierlin R. Tapper H. Tiecke M. Turala G. Waltermann S. Watts P. Weilhammer F. Wickens L. Wiggers A. Wylie T. Zeludziewicz ACCMOR Collaboration 《Zeitschrift fur Physik C Particles and Fields》1990,46(4):513-519
The production of the neutralK ? (892) resonances by 200 GeVK ? andπ ? has been studied over the kinematic range 0.0<x f<1.0 andp t 2 <5.0 GeV2. Longitudinal and transverse momentum distributions are presented. In addition the decay angular distributions inK ? fragmentation to \(\bar K^{0*} \) have been investigated. 相似文献
134.
H. -J. Simonis S. Kremeyer F. Hagelberg U. Reuter M. Knopp K. -H. Speidel J. Cub W. Karle P. N. Tandon J. Gerber 《Hyperfine Interactions》1990,61(1-4):1351-1354
From hyperfine interaction studles on free single electron16O(3−) ions. in a time differential mode using the recoil distance technique. It is shown that these ions are polarized when emerging
from magnetized thin layers of Fe. The observed degree of polarization
, however, is smaller than expected from transient field measurements. 相似文献
135.
We investigate representations of classical noncompact Lie groups induced by representations of the maximal parabolic subgroup. Formulas are obtained for 5O0(2p, 2q)/U(p, q) and U(2p, 2q) Sp(p, q).Translated from Ukrainskii Mathematicheskii Zhurnal, Vol. 42, No. 1, pp. 128–131, January, 1990. 相似文献
136.
Au/Pt(111) has been studied by spin-, angle- and energy-resolved photoemission with normal incident circularly polarized synchrotron radiation of BESSY and normal photoelectron emission for different Au coverages. The prepared layers were characterized by LEED and Augerelectron spectroscopy and turned out to grow up two dimensional and epitaxially. In the photoemission experiments the development of the 3-dimensional bandstructure in the -direction could be observed. For a coverage of 2.6 layers the highest occupied spin-orbit split bands are located at about 0.6 eV lower binding energy than the corresponding bands for a 3D-Au crystal and show dispersion which is, however, weaker than in a 3D-Au crystal. A 5 layer Au adsorbate was found to have already the same dispersion and energetic location as a Au(111)-crystal. For thick gold layers, which behave in photoemission like Au(111)-crystals, we find structures that cannot be due to direct transitions into a free electron like final band. The coverage dependence and spin polarization of these structures show that some of them are due to surface resonances, while the origin of one strong peak could not yet be explained conclusively. In addition we find strong hybridization and two avoided crossings in the occupied part of the bandstructure. 相似文献
137.
The spin content of the proton is investigated by studying the flavor singlet axial structure of the nucleon in a non-topological chiral soliton model. In order to construct a nucleon state we used the generator coordinate projection method as well as a coherent state for the meson wave function. Using a standard set of parameters we found the value g A 0 ? 0.44 for the flavor singlet axial vector coupling constant. This result is not far from that of a typical valence quark model. 相似文献
138.
The influence of impurity scattering is studied theoretically in a two-layer model for the high-T
c
superconductor Y1Ba2Cu3O7– with intra- and inter-layer pairing. Two types of impurities are considered: (I) impurities which conserve the reflection symmetry of the two layers and (II) impurities which break it. Impurities of type (I) have no influence on the critical temperature. Type (II) impurities have strong influence onT
c
as well as onH
c2
if there is a pairing interaction between carriers of different layers. The treatment of type (II) impurities is generalized to a periodic layer model appropriate for La2–x
Ba
x
CuO4. Available experiments on impurities in Y1Ba2Cu3O7– and La2–x
Ba
x
CuO4 are interpreted with our theory. 相似文献
139.
Dr. H. U. Buhl 《Mathematical Methods of Operations Research》1988,32(2):111-119
Contrary to the variety of models and procedures for optimizing the ordering decision in inventory control theory, no comparable tools exist for the scrapping decision. Thus, the current paper constitutes a step in this direction. Using a simple deterministic model, the basic economics and structure of the problem are introduced first. Then we determine explicitly scrap-optimal turn-around-times as well as the corresponding scrap- and rest-quantities. Accounting for the stochastic nature of demand, the model is generalized and algorithms for determination of optimal scrapping decision are discussed. Finally we compare the results and discuss practical applications. 相似文献
140.
Radiative processes and non-equilibrium thermodynamics 总被引:1,自引:0,他引:1
With the assumption of an elementary physical concept meteorologically effective radiative processes (absorption-emission, scattering) can be included consistently in nonequilibrium thermodynamics of irreversible phenomena. Analogously to the usual Gibbs relations a fundamental equation was formulated for monochromatic light rays as the nucleus of the theory.Using the methods of classical irreversible theory, a complete entropy balance equation is derived in which the entropy variations of the mass as well as of the radiation field are explicitly represented. The resulting entropy source strength function through its analytical structure reveals the dynamical character of the irreversible variation terms. The-expression being positive according to the second law of thermodynamics is found to have a bilinear form as a function of the irreversible fluxes representing the entropy generating radiative processes and their conjugated thermodynamic forces. The mathematical structure and the positive sign of, following the usual line of reasoning, motivate the assumption of constitutive relations for the irreversible radiative processes. These equations developed from purely thermodynamical reasoning turn out to be equivalent to the usual radiative transfer equation which is founded on a very different theoretical concept. A very fundamental relationship can be deduced in this context from the entropy production function. It provides a direct thermodynamical proof that in nonscattering media the definition of a local temperature is necessarily accompanied by the validity of the Kirchhoff law. 相似文献