Röntgenographische Phasenbestimmungen zur thermischen Dissoziation und das Hydrolyseverhalten von Alkalihexafluorogermanaten bei höheren Temperaturen

Phase Determinations by X-rays on the Thermal Dissociation and the Hydrolysis of Alkali Hexafluorogermanates at Higher Temperatures For a better understanding of the thermal dissociation of alcaline hexafluorosilicates investigations have been done on hexafluorogermanates. In these systems the formation of new phases has been studied by x-rays in dependence of temperature. Thermal behaviour of the substances strongly depends on the starting structure. Phase transformations taking place at lower temperatures are strongly determine the reaction at higher temperature. Therefore, we found differences to the analogous thermal reactions of hexafluorosilicates. There is a high sensitivity to hydrolysis of hexafluorogermanates above 600°C. We discuss the difference in reaction of thin powder layers and of powder samples in the volume.     

A remark on the localisation of a charged Bose field

We give two natural definitions for the local field algebras associated with a massive relativistic charged Bose field. These are both covariant, but are relatively antilocal in the sense of Segal and Goodman [1].They have the same representation of the Poincaré group, but are not in the same Borchers class [2].Research supported by the Science Research Council, London.     

Untersuchungen an Metallkatalysatoren. Zur Dispersit?t von Pt-Ir-Katalysatoren

Ohne Zusammenfassung     

Inductive limits and partitions of unity

Let E be the inductive limit of a family of locally convex topological vector spaces E_l. We introduce the concept of partitions of unity in E, which extends the usual partitions of unity in function spaces. Inductive limits admitting such a partition of unity have many interesting properties, similar to those of the strict inductive limits.They also have rather unusual properties concerning duals and spaces of mappings, which seem to be unknown, even in spaces likeD() andE().Some examples of such inductive limits are quoted at the end of the paper.     

The time evolution of quantized fields with bounded quasi-local interaction density

We extend to arbitrary dimension the proof by Guenin that the time-evolution is an automorphism group of the local algebras, if the interaction Hamiltonian is a space-integral of a bounded local density with finite range.Supported by the Science Research Council.     

Zur Kenntnis der μ-Peroxo-bis(pentacyanokobaltate(III)). Neuartige Darstellung,Beschreibung eines μ-Hydroperoxo-komplexes K5[Co2OOH(CN)10] · 2 H2O und eines μ-Peroxo-Carbonato-Komplexes K6[Co2CO4(CN)10] · 2 H2O

Investigations on Metal Catalysts. XXII. Chemisorption of Hydrogen on Pt? Ru and η-Al₂O₃ Supported Pt? Ru Catalysts Measurements of the H₂ chemisorption by volumetric method were carried out on several series of Pt? Ru and η-Al₂O₃ supported Pt? Ru catalysts. Addition of Ru to Pt and vice versa effects a remarkable influence on the sorption behaviour of the starting samples. For mixtures of carrier-free catalysts and η-Al₂O₃ as well as Pt? Ru/η-Al₂O₃ catalysts a hydrogen-spillover effect was found.     

Mach stem hysteresis: Experiments addressing a novel explanation of clumpy astrophysical jet emission

Recent time-series observations of shock waves in stellar jets taken with the Hubble Space Telescope reveal localized bright knots that persist over nearly 15 years. While some of these features represent shock fronts caused by variable velocities in the flow, others appear at the intersection points between distinct bow shocks. Theoretically, when the angle between two intersecting shocks exceeds a certain critical value, a third shock (Mach stem) should form. Because Mach stems form perpendicular to the direction of flow, incoming particles encounter a normal shock instead of an oblique one, which results in brighter emission at this location. To study this phenomenon in a controlled laboratory setting, we have carried out experiments on the Omega laser aimed at understanding the formation, growth, and destruction of Mach stems in the warm dense plasma regime. Our experimental results indicate how the growth rate depends upon included angle, and numerical simulations indicate that it may be possible to stabilize an already-formed Mach stem below the critical angle when certain conditions are satisfied.     

Information trade-offs for optical quantum communication

Recent work has precisely characterized the achievable trade-offs between three key information processing tasks-classical communication (generation or consumption), quantum communication (generation or consumption), and shared entanglement (distribution or consumption), measured in bits, qubits, and ebits per channel use, respectively. Slices and corner points of this three-dimensional region reduce to well-known protocols for quantum channels. A trade-off coding technique can attain any point in the region and can outperform time sharing between the best-known protocols for accomplishing each information processing task by itself. Previously, the benefits of trade-off coding that had been found were too small to be of practical value (viz., for the dephasing and the universal cloning machine channels). In this Letter, we demonstrate that the associated performance gains are in fact remarkably high for several physically relevant bosonic channels that model free-space or fiber-optic links, thermal-noise channels, and amplifiers. We show that significant performance gains from trade-off coding also apply when trading photon-number resources between transmitting public and private classical information simultaneously over secret-key-assisted bosonic channels.