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41.
We present the Fermi surface properties in strongly correlated electron systems of rare earth and uranium compounds via de Haas–van Alphen experiments. The conduction electrons with large cyclotron effective masses over 100m0 (m0: rest mass of an electron) are detected in CeRu2Si2, CeCoIn5 and UPt3. These electrons move slowly in the crystal. The topology of the Fermi surface and the cyclotron mass are compared to those of energy band calculations. 相似文献
42.
Tetsuya Hirade Frans H. J. Maurer Morten Eldrup 《Radiation Physics and Chemistry》2000,58(5-6):465-471
Measurements have been carried out of electron spin densities (by electron spin resonance technique) and positronium (Ps) formation probability as functions of Co-60 γ-irradiation dose in poly(methyl methacrylate) and linear poly(ethylene) at 77 K. We observe a linear relationship between the enhancement of the Ps formation and the density of trapped electrons in both polymers. This clear correlation strongly supports the previous suggestion by the authors that the increase in Ps formation with time (that has been observed at low temperatures for a number of polymers) can be explained as a reaction of free positrons with trapped electrons produced by the previously injected positrons. 相似文献
43.
《Communications in Nonlinear Science & Numerical Simulation》2014,19(5):1338-1346
Properties of obliquely propagating ion-acoustic solitons and double layers in a magnetized auroral plasma composed of hot adiabatic ions and two types of, cool and hot Maxwellian electrons are studied using Sagdeev pseudo-potential technique and assuming the quasi-neutrality condition. The new and surprising result which emerges from the model is that in contrast to the case of cold ions where ion-acoustic solitons and double layers are found for subsonic Mach numbers only, the hot ions case allows these nonlinear structures to exist for both subsonic and supersonic Mach number regimes. The double layers exist at lower angle of propagation as hot ion temperature is increased. The soliton electric field amplitudes are increased but their width and pulse duration are decreased with the increase in hot ion temperature. For the auroral zone parameters, the maximum electric field amplitude, width, pulse duration and speed for the solitons come out to be in the range ∼ (0.3–15) mV/m, ∼ (195–455) m, (7–20) ms and (22–26) km/s, respectively. The results seem to be in agreement with the Viking satellite observations in the auroral zone. 相似文献
44.
45.
用"删除法则"求3个同科电子的光谱项 总被引:11,自引:1,他引:10
提出了3个同科电子体系在L-S耦合中确定光谱项的“删除法则”,并加以证明.利用“删除法则”可以很方便地求出3个同科电子所形成的光谱项. 相似文献
46.
47.
S Chakraborty 《Pramana》1985,25(3):275-280
A theoretical study of theL-shell ionization of atoms by relativistic electrons is made for atomic numbers in the range 47 to 92. A new potential model
recently proposed by Das and Chakraborty dealing with atomic screening effect in a better way has been used. The results are
in satisfactory agreement when compared with some available experimental results and also with the theoretical results of
Scofield. 相似文献
48.
49.
We investigate temperature and concentration driven phase transitions (structural and reentrant phase transitions included) in magnetic and superconducting systems with the use of a wide class of model Hamiltonians applied to rare earth (Re) based compounds and alloys (integer and fluctuating valence systems). Studying the temperature or concentration dependence of the chemical potential we observe small but distinct and well localized kinks at all critical points as evidence for phase transitions. For systems with, at least, two kinds of interacting electrons the kinks at critical temperatures or concentrations occur also in the electronic average occupation numbers (critical electron redistribution). These observations suggest a direct and universal experimental application of the chemical potential as a detector of phase transitions for temperature and concentration driven phase transitions, as well as, for pressure-or external field-induced transitions in solids. The agreement between the calculated critical temperature behaviour of the chemical potential, presented in this paper, and experimental measurements for high-temperature superconductor YBa2Cu3O7-δ entirely supports these general observations. 相似文献
50.
We show that it is possible to produce terahertz wave generation in an open waveguide, which includes a multilayer dielectric plate. The plate consists of two dielectric layers with a corrugated interface. Electrons, drifting in the potential well, interact with the non-uniform electric field which is induced near the dielectric interface by the natural wave of the waveguide. The corrugated period and parameters of the electronic system are chosen in order to ensure the most effective interaction of electrons with a wave. Generation of electromagnetic waves is achieved by converting the electrons? energy into the electromagnetic wave energy. 相似文献