Forming and confining of dipolar excitons by quantizing magnetic fields

We show that a magnetic field perpendicular to an AlGaAs/GaAs coupled quantum well efficiently traps dipolar excitons and leads to the stabilization of the excitonic formation and confinement in the illumination area. Hereby, the density of dipolar excitons is remarkably enhanced up to $\sim 10^{11} cm^{-2}$. By means of Landau level spectroscopy we study the density of excess holes in the illuminated region. Depending on the excitation power and the applied electric field, the hole density can be tuned over one order of magnitude up to $\sim 2.5$ $10^{11} cm^{-2}$ - a value comparable with typical carrier densities in modulation-doped structures.Comment: 4.3 Pages, 4 Figure

Interaction of Spatially Localized LHW with Banana Particles

The paper proposes a novel mechanism of LHW stochastic acceleration of electrons in a tokamak

Energetics of metal slabs and clusters: the rectangle-box model

An expansion of energy characteristics of wide thin slab of thickness L in power of 1/L is constructed using the free-electron approximation and the model of a potential well of finite depth. Accuracy of results in each order of the expansion is analyzed. Size dependences of the work function and electronic elastic force for Au and Na slabs are calculated. It is concluded that the work function of low-dimensional metal structure is always smaller that of semi-infinite metal sample. A mechanism for the Coulomb instability of charged metal clusters, different from Rayleigh's one, is discussed. The two-component model of a metallic cluster yields the different critical sizes depending on a kind of charging particles (electrons or ions). For the cuboid clusters, the electronic spectrum quantization is taken into account. The calculated critical sizes of Ag_{N}^{2-} and Au_{N}^{3-} clusters are in a good agreement with experimental data. A qualitative explanation is suggested for the Coulomb explosion of positively charged Na_{\N}^{n+} clusters at 3<n<5.Comment: 11 pages, 6 figures, 1 tabl

Mass spectrometric comparison of swift heavy ion-induced and anaerobic thermal degradation of polymers

The study of polymers irradiated by highly energetic ions and the resulting radiation-induced degradation is of major importance for space and particle accelerator applications. The mechanism of ion-induced molecular fragmentation of polyethylene, polyethyleneimine and polyamide was investigated by means of mass spectrometry and infrared spectroscopy. The results show that the introduction of nitrogen and oxygen into the polymer influences the stability rendering aliphatic polymers with heteroatoms less stable. A comparison to thermal decomposition data from literature reveals that ion-induced degradation is different in its bond fracture mechanism. While thermal degradation starts at the weakest bond, which is usually the carbon-heteroatom bond, energetic ion irradiation leads in the first step to scission of all types of bonds creating smaller molecular fragments. This is due to the localized extreme energy input under non-equilibrium conditions when the ions transfer kinetic energy onto electrons. These findings are of relevance for the choice of polymers for long-term application in both space and accelerator facilities.We would like to thank the GSI for financial support and the material research group at GSI for given advice

AMADEUS: Towards the AutoMAteD secUrity teSting

The proper configuration of systems has become a fundamental factor to avoid cybersecurity risks. Thereby, the analysis of cyber security vulnerabilities is a mandatory task, but the number of vul nerabilities and system configurations that can be threatened is ex tremely high. In this paper, we propose a method that uses software product line techniques to analyse the vulnerable configuration of the systems. We propose a solution, entitled AMADEUS, to enable and support the automatic analysis and testing of cybersecurity vulnerabilities of configuration systems based on feature models. AMADEUS is a holistic solution that is able to automate the analy sis of the specific infrastructures in the organisations, the existing vulnerabilities, and the possible configurations extracted from the vulnerability repositories. By using this information, AMADEUS generates automatically the feature models, that are used for rea soning capabilities to extract knowledge, such as to determine attack vectors with certain features. AMADEUS has been validated by demonstrating the capacities of feature models to support the threat scenario, in which a wide variety of vulnerabilities extracted from a real repository are involved. Furthermore, we open the door to new applications where software product line engineering and cybersecurity can be empowered.Ministerio de Ciencia, Innovación y Universidades RTI2018-094283-B-C33 (ECLIPSE)Junta de Andalucía P20-01224 (COPERNICA)Junta de Andalucía US-1381375 (METAMORFOSIS

Middle managers’ struggle over their subject position in Open Strategy processes

In this paper we examine the struggle of middle managers over their subject position as strategists in the context of participative strategy processes. Based on a longitudinal, real-time case study of a company undertaking an Open Strategy process, we show how the wider inclusion of front-line employees in developing new strategy undermines the traditional subject position of middle managers. Based on these findings, we develop a process model depicting the recursive dynamics of middle managers’ struggles to maintain their subject positions in the face of employee participation. With these findings we contribute to the literature on middle managers by advancing our understanding of the implications of employee participation for middle managers’ subject position as strategists and their different ways of reclaiming their subject position. We also contribute to the literature on Open Strategy by revealing the challenges of participatory strategy-making processes and the implications for traditional strategy actors as well as by explaining the processual dynamics of participation over time