排序方式: 共有48条查询结果,搜索用时 312 毫秒
31.
Donor spin - flip transitions with ΔN = 0, ΔM = ?1, and Δλ = 1 are observed in InSb in high magnetic fields using an optically pumped far-infrared laser system. Variational calculations of the donor levels yielded good agreement with previously observed donor transitions energies. As regards the new spin - flip transitions reported in this work, the theoretical treatment has to be revised particularly for obtaining correct selection rules. 相似文献
32.
The integer Quantum Hall effect has been recently observed in the Hall conductivity
xy
at microwave frequencies. Here we present a calculation of the wave propagation in the crossed waveguide system used in the experiments. The field pattern is more complicated than in the case of a pure plane wave. The essential result, however, remains unchanged: The field strength in the second (crossed) waveguide is proportional to
xy
of the two-dimensional electron gas.
Dedicated to Professor Karlheinz Seeger on the occasion of his 60th birthday 相似文献
33.
34.
35.
On the effect of non-parabolicity in the quantum-mechanical treatment of cyclotron resonance in n-Ge
F. Kuchar 《Zeitschrift für Physik B Condensed Matter》1977,26(3):223-226
The quantum-mechanical expression for
± including non-parabolicity of the conduction band is applied to the case of the transverse-mass resonance of n-Ge in the quantum regime aroundk
B
T~ (=5.6×1012s–1). The essential results concern the resonance position in the transmittivity (shift with temperature) and the line shape (asymmetric absorption). 相似文献
36.
37.
38.
J.H. Smet B. Gorshunov C. Jiang L. Pfeiffer K. West V. Umansky M. Dressel R. Meisels F. Kuchar K. von Klitzing 《Physica E: Low-dimensional Systems and Nanostructures》2006,35(2):315
We have investigated the influence of the polarization of the incident radiation on the recently discovered microwave-induced resistance oscillations in state-of-the-art highest purity 2D electron systems. A quasi-optical setup allows us to tune in situ between different circular as well as linear polarization states. We find that the microwave-induced zero resistance and the resistance oscillations are notably immune to changes in the polarization. This observation is discrepant with a number of proposed theories. Deviations for different polarizations only occur for a bolometric contribution to the resistance associated with the resonant heating at the cyclotron resonance itself. 相似文献
39.
Kuchar M Pohl R Klepetárová B Votruba I Hocek M 《Organic & biomolecular chemistry》2008,6(13):2377-2387
Synthesis of novel purine bases and nucleosides bearing unsubstituted or substituted cyclopropyl rings in position 6 is reported. Unsubstituted 6-cyclopropylpurines were efficiently prepared by cross-coupling reactions of 6-chloropurines with cyclopropylzinc chloride. 6-Vinylpurines underwent Cu-mediated cyclopropanations with ethyl diazoacetate to give 6-[(ethoxycarbonyl)cyclopropyl]purines that were further transformed to carboxylic acids, amides and alcohols. 6-Cyclopropylpurine ribonucleoside exerted a significant cytostatic effect while all substituted derivatives were inactive. 相似文献
40.