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151.
Let be a densely defined operator on a Banach space X. Characterizations of when generates a C0‐semigroup on X are known. The famous result of Lumer and Phillips states that it is so if and only if is dissipative and is dense in X for some . There exists also a rich amount of Banach space results concerning perturbations of dissipative operators. In a recent paper Tyran–Kamińska provides perturbation criteria of dissipative operators in terms of ergodic properties. These results, and others, are shown to remain valid in the setting of general non–normable locally convex spaces. Applications of the results to concrete examples of operators on function spaces are also presented. 相似文献
152.
Anne Davaille Angela Limare Floriane Touitou Ichiro Kumagai Judith Vatteville 《Experiments in fluids》2011,50(2):285-300
We present an experimental study of the dynamics of a plume generated from a small heat source in a high Prandtl number fluid
with a strongly temperature-dependent viscosity. The velocity field was determined with particle image velocimetry, while
the temperature field was measured using differential interferometry and thermochromic liquid crystals. The combination of
these different techniques run simultaneously allows us to identify the different stages of plume development, and to compare
the positions of key-features of the velocity field (centers of rotation, maximum vorticity locations, stagnation points)
respective to the plume thermal anomaly, for Prandtl numbers greater than 103. We further show that the thermal structure of the plume stem is well predicted by the constant viscosity model of Batchelor
(Q J R Met Soc 80: 339–358, 1954) for viscosity ratios up to 50. 相似文献
153.
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155.
Angela Bonaccorso 《Acta Physica Hungarica A》2003,18(2-4):193-202
This article examines a number of reaction mechanisms for scattering initiated by an exotic projectile. Comparisons are made with recent experimental data, in order to extract information on the peculiarity of the nuclear structure under extreme conditions and to test the accuracy of the available theoretical methods. Predictions for future experiments are also made. 相似文献
156.
Angela Mller 《无机化学与普通化学杂志》2005,631(12):2285-2296
The aim of this research report is to give an introduction to a specific solid state reaction applied in the field of alkali metal rich transition metal compounds. The approach is an explorative investigation of the oxidation of transition metals with CdO in the presence of alkali metal oxides and / or compounds with complex anions such as Na2SO4. Thereby, a range of unusual compounds have been obtained and structurally characterized. In particular, low valences and uncommon coordination numbers (C.N.) of the late 3d transition metals, as well as interesting varieties in the anionic part of the structures are accessible. The presented examples were selected mainly in order of their inherent aspects concerning the reactivity, structural features or electronic structures. 相似文献
157.
Armandodoriano BiancoClaudia Cavarischia Angela FarinaMarcella Guiso Carolina Marra 《Tetrahedron letters》2003,44(51):9107-9109
Several naturally occurring flavonoids have been synthesised following a new proposed method based on the use of the Heck reaction. The key step involves the coupling of an aryl vinyl ketone with an aryl iodide. This procedure affords the flavonoid moiety in a single step. 相似文献
158.
For group III-nitrides with wurtzite structure the presence of fixed polarization interface charges yields new challenges in order to understand and control Schottky barrier heights, band offsets and 2D confinement in heterostructure FETs. In this short review experimental results obtained by in situ photoemission spectroscopy on MBE AlGaN/GaN heterostructures grown on 6H–SiC are discussed, with emphasis on the presence and interplay of surface electronic states. Schrödinger–Poisson calculations are performed to get the complete band scheme at the selected heterojunctions. Results on the polarity dependence of Pt/GaN Schottky barrier values from the literature are also discussed. 相似文献
159.
Angela Desai 《Indagationes Mathematicae》2006,17(3):353-359
We prove that any ?d shift of finite type with positive topological entropy has a family of subsystems of finite type whose entropies are dense in the interval from zero to the entropy of the original shift. We show a similar result for ?d sofic shifts, and also show every ?d sofic shift can be covered by a ?d shift of finite type arbitrarily close in entropy. 相似文献
160.
Regioselective Acceptorless Dehydrogenative Coupling of N‐Heterocycles toward Functionalized Quinolines,Phenanthrolines, and Indoles
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Dinesh Talwar Angela Gonzalez‐de‐Castro Dr. Ho Yin Li Prof. Jianliang Xiao 《Angewandte Chemie (International ed. in English)》2015,54(17):5223-5227
A new strategy has been developed for the oxidant‐ and base‐free dehydrogenative coupling of N‐heterocycles at mild conditions. Under the action of an iridium catalyst, N‐heterocycles undergo multiple sp3 C? H activation steps, generating a nucleophilic enamine that reacts in situ with various electrophiles to give highly functionalized products. The dehydrogenative coupling can be cascaded with Friedel–Crafts addition, resulting in a double functionalization of the N‐heterocycles. 相似文献