Transition to turbulence in a non-standard rotating flow

Characteristic features of the transition to turbulence in standard Taylor-Couette flow are the persistence of cellular structure and residual temporal order to high values of the Reynolds number R. We report here the results of an experimental investigation in a non-standard system which has discrete symmetries. The transition process is found to be charged qualitatively and has features common to other non-linear systems. In addition, a state of temporal and spatial chaos is achieved at moderate values of R.     

Über die Gleichstetigkeit von Mengen von linearen Abbildungen und eine Klasse von topologischen linearen Räumen

In the first part of this paper we proof the following theorem: Let E and F be topological linear spaces, α an infinite cardinal number, and H a set of linear mappings from E into F such that every subset G of H with cardinality |G|≤α is equicontinuous. Then H is equicontinuous on every linear subspace of E which is the closed linear hull of a family (B_L;L∈I), |I|≤α, of precompact subsets of E. In the second part we introduce the class of all topological linear spaces E with the following property: A set H of linear mappings from E into a topological linear space is equicontinuous, if every countable subset of H is equicontinuous. We show that this class is closed with respect to forming topological products and linear final topologies.     

Multiplikative quadratische Formen

Ohne Zusammenfassung     

Correlation inequalities for some classical spin vector models

Correlation inequalities are derived for a class of lattice systems including some classical anisotropic X-Y and Heisenberg ferromagnets. In particular, a comparison is estab- lished between some correlation functions of the X-Yand Heisenberg models.     

Control of chaotic Taylor-Couette flow with time-delayed feedback

We demonstrate that unstable periodic orbits embedded in the experimental chaotic attractor determined by the Taylor-Couette flow can be stabilized with a time-delay autosynchronization algorithm. The optimal parameters of the feedback and their dependence on the control parameter are shown as experimental results.     

Low voltage green LED on ZnTe obtained by a simultaneous double diffusion procedure

We report electrical and optical properties of green (5515 Å at 300 K — half maximum width 76 Å) LED using p-type ZnTe and simultaneous diffusion of aluminium and lithium. Electroluminescence is obtained when the device is forward biased. No luminescence has been observed for reverse bias. The injection mechanism is supposed to be double injection in an insulating layer as in ion-implanted green LED, but this insulating layer we obtain is much thinner than the one obtained by ion implantation. As a consequence the threshold voltage for electroluminescence decreases from 6 V to 2.5-3 V.     

On the hadron contributions to high-energy quantum electrodynamics

Without taking into account the electromagnetic structure, caused by the strong interactions, all charged particles contribute with nearly the same weight to the electromagnetic vacuum polarization at very high energy. The structure effects come in via the form factors at timelike momentum transfer. By making use of the strong asymptotic decrease of the nucleon form factors for spacelike argument, it is inferred from an unsubtracted dispersion relation that the nucleon contribution to vacuum polarization can be neglected asymptotically, compared to the contribution of the unstructured leptons.     

A site-selective dual anchoring strategy for artificial metalloprotein design

Introducing nonnative metal ions or metal-containing prosthetic groups into a protein can dramatically expand the repertoire of its functionalities and thus its range of applications. Particularly challenging is the control of substrate-binding and thus reaction selectivity such as enantioselectivity. To meet this challenge, both non-covalent and single-point attachments of metal complexes have been demonstrated previously. Since the protein template did not evolve to bind artificial metal complexes tightly in a single conformation, efforts to restrict conformational freedom by modifying the metal complexes and/or the protein are required to achieve high enantioselectivity using the above two strategies. Here we report a novel site-selective dual anchoring (two-point covalent attachment) strategy to introduce an achiral manganese salen complex (Mn(salen)), into apo sperm whale myoglobin (Mb) with bioconjugation yield close to 100%. The enantioselective excess increases from 0.3% for non-covalent, to 12.3% for single point, and to 51.3% for dual anchoring attachments. The dual anchoring method has the advantage of restricting the conformational freedom of the metal complex in the protein and can be generally applied to protein incorporation of other metal complexes with minimal structural modification to either the metal complex or the protein.     

Analyticity properties of the correlation functions for the anisotropic Heisenberg model

It is shown for the Heisenberg model that the correlation functions are analytic inh andT if Re(h)≠0 andT is positive.