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21.
At temperatures above the brittle-to-ductile transition (490 °C) in Te-doped GaAs three types of predominant defect configurations have been observed after uniaxial compression along a [001] direction: (i) twins and stacking faults (500 … 520 °C), (ii) slip zones of dislocations (≈550 °C) and (iii) dislocation cells (580 … 590 °C). In Part II quantitative details of the appearance of slip and cell formation are given. Leading segments of gliding half loops are mainly of 60° type. Cell walls were formed by multiple slip of perfect dislocations. 相似文献
22.
23.
F. W. N. de Boer H. J. Wollersheim H. Emling H. Grein E. Grosse W. Spreng G. Eckert Th. W. Elze K. Stelzer Ch. Lauterbach 《Zeitschrift für Physik A Hadrons and Nuclei》1986,325(4):457-466
In a systematic study of nucleon transfer reactions accompanied by Coulomb excitation we have bombarded152Sm,160Gd and232Th with206, 208pb beams at incident energies close to the Coulomb barrier. Particle-gamma coincidence techniques were used to identify excited states of reaction products populated through inelastic scattering and in nucleon transfer reactions. One-neutron stripping and pick-up reactions on152Sm were observed leading to known states of the rotation alignedi 13/2-bands in153Sm and151Sm. In the160Gd+206, 208Pb systems no significant population of low lying states of product nuclei was found in the nucleon-transfer channels. Large cross sections were observed for one- and two-neutron pick-up from232Th at an incident energy of 6.4 MeV/u. Around the grazing angle they are of the same order of magnitude as the cross section measured for inelastic scattering. The results are analyzed in the framework of semiclassical models. 相似文献
24.
We study quartic matrix models with partition function \({\mathcal{Z}[E, J] = \int dM}\) exp(trace \({(JM - EM^{2} - \frac{\lambda}{4} M^4)}\) ). The integral is over the space of Hermitean \({\mathcal{N} \times \mathcal{N}}\) -matrices, the external matrix E encodes the dynamics, \({\lambda > 0}\) is a scalar coupling constant and the matrix J is used to generate correlation functions. For E not a multiple of the identity matrix, we prove a universal algebraic recursion formula which gives all higher correlation functions in terms of the 2-point function and the distinct eigenvalues of E. The 2-point function itself satisfies a closed non-linear equation which must be solved case by case for given E. These results imply that if the 2-point function of a quartic matrix model is renormalisable by mass and wavefunction renormalisation, then the entire model is renormalisable and has vanishing β-function. As the main application we prove that Euclidean \({\phi^4}\) -quantum field theory on four-dimensional Moyal space with harmonic propagation, taken at its self-duality point and in the infinite volume limit, is exactly solvable and non-trivial. This model is a quartic matrix model, where E has for \({\mathcal{N} \to \infty}\) the same spectrum as the Laplace operator in four dimensions. Using the theory of singular integral equations of Carleman type we compute (for \({\mathcal{N} \to \infty}\) and after renormalisation of \({E, \lambda}\) ) the free energy density (1/volume) log \({(\mathcal{Z}[E, J]/\mathcal{Z}[E, 0])}\) exactly in terms of the solution of a non-linear integral equation. Existence of a solution is proved via the Schauder fixed point theorem. The derivation of the non-linear integral equation relies on an assumption which in subsequent work is verified for coupling constants \({\lambda \leq 0}\) . 相似文献
25.
Self-injection length in La0.7Ca0.3MnO3-YBa2Cu3O7-δ ferromagnet-superconductor multilayer thin films
We have carried out extensive studies on the self-injection problem in barrierless heterojunctions between La0.7Ca0.3MnO3 (LCMO) and YBa2Cu3O7-δ (YBCO) thin films. The heterojunctions were formed in situ by sequentially growing LCMO and YBCO films on 〈100〉 LaAlO3 (LAO) substrate using a pulsed laser deposition (PLD) system. YBCO micro-bridges with 64 μm width were patterned both on
the LAO (control) and LCMO side of the substrate. Critical current, I
c, was measured at 77 K on both the control side as well as the LCMO side for different YBCO film thickness. It was observed
that while the control side showed a J
c of ∼ 2 × 106 A/cm2, the LCMO side showed about half the value for the same thickness (1800 ?). The difference in J
c indicates that a certain thickness of YBCO has become ‘effectively’ normal due to self-injection. From the measurement of
J
c at two different thicknesses (1800 ? and 1500 ?) of YBCO films both on the LAO as well as the LCMO side, the value of self-injection
length (at 77 K) was estimated to be ∼ 900 ?. To the authors’ best knowledge, this is the first time that self-injection length
has been quantified. A control experiment carried out with LaNiO3 deposited by PLD on YBCO did not show any evidence of self-injection. 相似文献
26.
We have experimentally demonstrated how two beams of light separated by an octave in frequency can become entangled after their interaction in a chi;{(2)} nonlinear medium. The entangler was a nonlinear optical resonator that was strongly driven by coherent light at the fundamental and second-harmonic wavelengths. An interconversion between the fields created quantum correlations in the amplitude and phase quadratures, which were measured by two independent homodyne detectors. Analysis of the resulting correlation matrix revealed a wave function inseparability of 0.74(1)<1, thereby satisfying the criterion of entanglement. 相似文献
27.
Blaschke Daniel N. Grosse Harald Kronberger Erwin Schweda Manfred Wohlgenannt Michael 《The European Physical Journal C - Particles and Fields》2010,69(3-4):575-579
The European Physical Journal C - Motivated by the success of the non-commutative scalar Grosse–Wulkenhaar model, a non-commutative U ⋆(1) gauge field theory including an... 相似文献
28.
Pauli Hamiltonians with first-order relativistic corrections according to Foldy and Wouthuysen are rigorously studied applying methods of singular perturbation theory. The results include a proof of first-order spectral concentration in the non-relativistic limit and a characterization of first-order pseudoeigenvalues by means of formal perturbation theory. 相似文献
29.
P. Grosse B. Harbecke B. Heinz R. Meyer M. Offenberg 《Applied Physics A: Materials Science & Processing》1986,39(4):257-268
Measurements of the reflectance and transmittance in the infrared part of the spectrum (400...4000cm–1) are carried out on oxidized Si wafers. Intrinsic dielectric properties of the oxide layers prepared by various methods are derived from experimental data. The dielectric functions of the oxides can be fitted by oscillator models. The related model parameters are compared with those of other SiO2 samples, as crystals and glasses. Optical arrangements to detect and characterize layers of thicknesses down to 3 nm are discussed. In particular, it is shown that experiments with polarized light at oblique incidence up to 80° are a powerful tool to characterize those layers.Experiments are reported to determine, in addition, extrinsic properties such as B and P atoms in the oxide layer or defects due to an ion implantation treatment.Conditions are discussed which should be applied to obtain the best quantitative analysis of the defect concentration. 相似文献
30.
A. Mauthofer K. Stelzer J. Idzko Th. W. Elze H. J. Wollersheim H. Emling P. Fuchs E. Grosse D. Schwalm 《Zeitschrift für Physik A Hadrons and Nuclei》1990,336(3):263-278
The nuclear level structure and electromagnetic properties of196Pt were investigated withγ-spectroscopic techniques using multiple Coulomb excitation by208Pb projectiles. Particle-γ, and particle-γ-γ coincidences were measured over a wide range of scattering angles.E2-transition moments and static quadrupole moments have been determined by a comparison of experimental scattering-angle dependentγ yields with calculated yields in a largely model-independent procedure. The results are compared with different theoretical models: the Asymmetric-Rotor Model, the Generalized Collective Model, and the Interacting Boson Model. The best agreement is obtained with the Generalized Collective Model representing a triaxial nucleus which is soft in theγ degree of freedom. 相似文献