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151.
Wolfhard Hansen 《Potential Analysis》2017,46(1):1-21
We consider the stochastic differential equation (SDE) of the form where \(\sigma :{\mathbb {R}}^ d\to {\mathbb {R}}^ d\) is globally Lipschitz continuous and L={L(t):t≥0} is a Lévy process. Under this condition on σ it is well known that the above problem has a unique solution X. Let \((\mathcal {P}_{t})_{t\ge 0}\) be the Markovian semigroup associated to X defined by \(\left ({\mathcal {P}}_{t} f\right ) (x) := \mathbb {E} \left [ f(X^ x(t))\right ]\), t≥0, \(x\in {\mathbb {R}}^{d}\), \(f\in \mathcal {B}_{b}({\mathbb {R}}^{d})\). Let B be a pseudo–differential operator characterized by its symbol q. Fix \(\rho \in \mathbb {R}\). In this article we investigate under which conditions on σ, L and q there exist two constants γ>0 and C>0 such that
相似文献
$$\begin{array}{@{}rcl@{}} \left\{\begin{array}{rcl} dX^ x(t) &=& \sigma(X(t-)) dL(t) \\ X^ x(0)&=&x,\quad x\in{\mathbb{R}}^ d, \end{array}\right. \end{array} $$
$$\left| B {\mathcal{P}}_{t} u \right|_{H^{\rho}_{2}} \le C \, t^{-\gamma} \,\left| u \right|_{H^{\rho}_{2}}, \quad \forall u \in {H^{\rho}_{2}}(\mathbb{R}^{d} ),\, t>0. $$
152.
M. Wegscheider C. Simbrunner R. Jakie?a M. Quast A. Bonanni 《Applied Surface Science》2008,255(3):731-733
High p-type conductivity of GaN - commonly achieved via doping with Mg - is a challenge to be faced on the way to the realization of a GaN-based diluted magnetic semiconductor showing ferromagnetism at room temperature. In this work we present a study of GaN:Mg films grown in a metalorganic vapor phase epitaxy process where the Mg atoms are incorporated in a δ-doping fashion. The effect of a post-growth annealing step on the diffusivity of magnesium is studied by means of atomic force microscopy and photoluminescence measurements in the ultraviolet regime. A comparison of the presented results with transmission electron microscopy studies leads to the conclusion that a considerable amount of Mg is transported towards the surface where it is thermally removed during the annealing step. 相似文献
153.
154.
A.F. Dethlefsen E. Mariani W. Wegscheider R.J. Haug 《Physica E: Low-dimensional Systems and Nanostructures》2006,34(1-2):108
The activation energy Δ of the fractional quantum Hall state at constant filling factor and also at and has been measured as a function of the perpendicular magnetic field B while modulating the electron density via a top gate. At small magnetic fields we observe a linear increase of Δ with the magnetic field. The slope of Δ vs. B allows us to directly extract the composite fermion g-factor. 相似文献
155.
We experimentally study the energy gap within the incompressible strip at local filling factor ν
c
= 1 at the quantum Hall edge for samples of very different mobilities. The obtained results indicate strong enhancement of
the energy gap in comparison to the single-particle Zeeman splitting. We identify the measured gap as a mobility gap, so a
pronounced experimental in-plane magnetic field dependence can both be attributed to the spin effects as well as to the change
in the energy levels broadening. 相似文献
156.
Ilya Kuselman Maria Belli Stephen L. R. Ellison Ales Fajgelj Umberto Sansone Wolfhard Wegscheider 《Accreditation and quality assurance》2007,12(11):563-567
Comparability and compatibility of proficiency testing (PT) results are discussed for schemes with a limited number of participants
(less than 20–30) based on the use of reference materials (RMs) as test items. Since PT results are a kind of measurement/analysis/test
result, their comparability is a property conditioned by traceability to measurement standards applied in the measurement
process. At the same time, metrological traceability of the certified value of the RM (sent to PT participants as test items)
is also important, since the PT results are compared with the RM certified value. The RM position in the calibration hierarchy
of measurement standards sets the degree of comparability for PT results, which can be assessed in the scheme. However, this
assessment is influenced by commutability (adequacy or match) of the matrix RM used for PT and routine samples. Compatibility
of PT results is a characteristic of the collective (group) performance of the laboratories participating in PT that can be
expressed as closeness of the distribution of the PT results to the distribution of the RM data. Achieving quality-of-measurement/analysis/test
results in the framework of the concept “tested once, accepted everywhere” requires both comparability and compatibility of
the test results. 相似文献
157.
We investigate the Kondo effect and spin blockade observed in a many-electron quantum dot and study the magnetic field dependence. At lower fields, a pronounced Kondo effect is found, which is replaced by the spin blockade at higher fields. In an intermediate regime, both effects are visible. We make use of this combined effect to gain information about the internal spin configuration of our quantum dot. We find that the data cannot be explained assuming regular filling of electronic orbitals. Instead, spin polarized filling seems to be probable. 相似文献
158.
Dr. Rud Wegscheider 《Monatshefte für Chemie / Chemical Monthly》1890,11(1):538-544
Ohne Zusammenfassung 相似文献
159.
Ohne Zusammenfassung 相似文献
160.
Wolfhard Hansen 《Mathematische Annalen》2006,334(3):643-678
Given a Green function G (e.g. with respect to (−Δ)α/2, 0<α≤2) on a region X where G has a generalized triangle property and given a (G-bounded) signed measure μ on X, necessary and sufficient conditions are given for the existence of a perturbed Green function which is comparable with G. This is done in the general setting of measurable spaces. Applications to C1,1-regions in Rd and, for the classical case α=2, to finitely connected regions in ℝ2 are given. 相似文献