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The model system Pd/TiO2 (110) was used to evaluate the correlation between metal encapsulation and electronic structure of TiO2 crystals. We observed encapsulation of Pd clusters supported on TiO2 crystals, which were heavily Ar+ sputtered, Nb-doped, or reduced by vacuum annealing. In contrast, encapsulation was not observed on unreduced, undoped, or slightly sputtered TiO2 crystals. Our results indicate a strong dependence of the encapsulation process on the electron density in the conduction band of TiO2 and on the space charge formed at Pd/TiO2 interfaces. This behavior is controlled by the initial position of the Fermi energy level (EF) of the metal and the oxide before contact is established. We proved that encapsulation reactions are favored by n-type doping of the oxide and a large work function of the metal. On the basis of this mechanism, we conclude on general trends controlling encapsulation reactions of oxide-supported metal clusters and the strong metal-support interaction (SMSI).

The GPGP/TAEMS domain-independent coordination framework for small agent groups was first described in 1992 and then more fully detailed in an ICMAS'95 paper. In this paper, we discuss the evolution of this framework which has been motivated by its use in a number of applications, including: information gathering and management, intelligent home automation, distributed situation assessment, coordination of concurrent engineering activities, hospital scheduling, travel planning, repair service coordination and supply chain management. First, we review the basic architecture of GPGP and then present extensions to the TAEMS domain-independent representation of agent activities. We next describe extensions to GPGP that permit the representation of situation-specific coordination strategies and social laws as well as making possible the use of GPGP in large agent organizations. Additionally, we discuss a more encompassing view of commitments that takes into account uncertainty in commitments. We then present new coordination mechanisms for use in resource sharing and contracting, and more complex coordination mechanisms that use a cooperative search among agents to find appropriate commitments. We conclude with a summary of the major ideas underpinning GPGP, an analysis of the applicability of the GPGP framework including performance issues, and a discussion of future research directions.

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The microwave response of high quality niobium films in a perpendicular static magnetic field has been investigated. The complex frequency shift was measured up to the upper critical fields. The data have been analyzed by the effective conductivity model for the type-II superconductors in the mixed state. This model is found to yield consistent results for the coherence lengths in high-κ superconducting samples, and can be used with HTSC even at temperatures much below Tc. It is shown that for samples with high values of depinning frequency, one should measure both components of the complex frequency shift in order to determine the flow resistivity.The thick Nb film (160 nm) has low resistivity at 10 K, comparable to the best single crystals, and low κ value. In contrast, the thinnest (10 nm) film has κ ≈ 9.5 and exhibits a high depinning frequency (≈ 20 GHz). The upper critical field determined from microwave measurements is related to the radius of nonoverlaping vortices, and appears to be larger than the one determined by the transition to the normal state.

In the last decade, visible‐light photoredox catalysis has evolved into a versatile tool in organic synthesis. However, most reports have used homemade photoreactors in their design and optimisation of new methods, complicating the reproducibility of some transformations. To improve reproducibility and efficiency, laboratory photoreactors have been developed and commercialized. Herein we report a comparison of four commercially available photoreactors in six mechanistically distinct photoredox reactions focusing on the difference in product yields and kinetics as well as the factors which lead to these differences, including reaction temperature and light intensity.

Al 1 − x In x N layers with an indium content between x=10.5% and x=24% were grown by metal-organic vapor-phase epitaxy and characterized concerning their optical, structural and morphological properties with regard to the realization of optoelectronic devices. The indium content and the strain of these layers were measured by high resolution x-ray diffraction. Ellipsometric measurements were used to determine the optical constants [refractive index n(λ) and extinction coefficient κ(λ)] in dependence of wavelength and indium content. The values determined for the electronic bandgaps are in good agreement with theoretical predictions and previous publications on this topic but are more focused on AlInN layers which are pseudomorphically grown on GaN. A bowing parameter of b=10.3±0.1 was determined for fully strained layers with an indium content between 13% and 24%. In order to investigate the suitability of these layers for use in distributed Bragg reflectors, the surface morphology is characterized with respect to the indium content. Furthermore, the influence of an annealing step which often is necessary during device growth, was studied. The influence of this annealing step on the roughness was analyzed by atomic force microscopy, while structural features are monitored by high resolution secondary electron microscopy images. Based on these results distributed Bragg reflectors for the green spectral region with up to 40 pairs and a peak reflectivity of 97% have been realized. Transmission electron microscopic analysis of the layer interfaces are in good agreement with the atomic force and secondary electron microscopy images of the single layer surfaces.