812 research outputs found

    Relevanz soziokultureller Faktoren für die Strategieumsetzung in Familienunternehmen – eine empirische Untersuchung anhand von Conrad Electronic

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    The thesis investigates the relevance and impact of the Competing Values Framework and selected social cultural factors of Edgar Schein regarding the implementation of strategies in family owned businesses. The qualitative research project is conducted as an empirical case study. Guided interviews with senior experts from strategic relevant areas of the family business of Conrad Electronic and debriefings with external senior executives, who reflect on their experiences of working in family owned businesses and challenge the findings of the interviews, are applied to discover the social cultural root causes that lead to the failure of strategic implementations in family owned businesses. An extensive review of international research projects, literature, models regarding the process of strategy implementation and cultural frameworks provide the academic foundation for the thesis. However, questions regarding the relevance and impact of the Competing Value Framework and the selected set of social cultural factors regarding the implementation of strategies in family owned businesses have not been researched to a degree that allow derivations with practical advices of how to cope with the social cultural challenges arising from transforming or renewing business models. Addressing the research gap, the thesis target to confirm or reject the relevance and impact of the Competing Value Framework selected social cultural factors of Edgar Schein, to build a deeper understanding of the Interrelations of selected social cultural factors and to provide meaningful advices to business leaders and practitioners. Novel insights of the relevance, impact and interrelations of the Competing Value Framework and selected cultural factors of Edgar Schein aim to support strategic leadership and improve decision-making processes of relevant leaders and practitioners, which increase the probability of a successful strategy implementation and therefore the chances of the ongoing continuance of family owned businesses

    Tunable Superconducting Phase Transition in Metal-Decorated Graphene Sheets

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    Using typical experimental techniques it is difficult to separate the effects of carrier density and disorder on the superconducting transition in two dimensions. Using a simple fabrication procedure based on metal layer dewetting, we have produced graphene sheets decorated with a non-percolating network of nanoscale tin clusters. These metal clusters both efficiently dope the graphene substrate and induce long-range superconducting correlations. This allows us to study the superconducting transition at fixed disorder and variable carrier concentration. We find that despite structural inhomogeneity on mesoscopic length scales (10-100 nm), this material behaves electronically as a homogenous dirty superconductor. Our simple self-assembly method establishes graphene as an ideal tunable substrate for studying induced two-dimensional electronic systems at fixed disorder and our technique can readily be extended to other order parameters such as magnetism

    Spectral Properties and Linear Stability of Self-Similar Wave Maps

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    We study co--rotational wave maps from (3+1)(3+1)--Minkowski space to the three--sphere S3S^3. It is known that there exists a countable family {fn}\{f_n\} of self--similar solutions. We investigate their stability under linear perturbations by operator theoretic methods. To this end we study the spectra of the perturbation operators, prove well--posedness of the corresponding linear Cauchy problem and deduce a growth estimate for solutions. Finally, we study perturbations of the limiting solution which is obtained from fnf_n by letting nn \to \infty.Comment: Some extensions added to match the published versio

    PT Symmetric, Hermitian and P-Self-Adjoint Operators Related to Potentials in PT Quantum Mechanics

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    In the recent years a generalization H=p2+x2(ix)ϵH=p^2 +x^2(ix)^\epsilon of the harmonic oscillator using a complex deformation was investigated, where \epsilon\ is a real parameter. Here, we will consider the most simple case: \epsilon even and x real. We will give a complete characterization of three different classes of operators associated with the differential expression H: The class of all self-adjoint (Hermitian) operators, the class of all PT symmetric operators and the class of all P-self-adjoint operators. Surprisingly, some of the PT symmetric operators associated to this expression have no resolvent set

    Symmetrical Differential Operators and Their Friedrichs Extension

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    AbstractSymmetric operator realizations of ordinary regular differential expressions are characterized explicitly by boundary conditions. For any such operator which is bounded below, the boundary condition determining its Friedrichs extension is identified

    Multiply Folded Graphene

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    The folding of paper, hide, and woven fabric has been used for millennia to achieve enhanced articulation, curvature, and visual appeal for intrinsically flat, two-dimensional materials. For graphene, an ideal two-dimensional material, folding may transform it to complex shapes with new and distinct properties. Here, we present experimental results that folded structures in graphene, termed grafold, exist, and their formations can be controlled by introducing anisotropic surface curvature during graphene synthesis or transfer processes. Using pseudopotential-density functional theory calculations, we also show that double folding modifies the electronic band structure of graphene. Furthermore, we demonstrate the intercalation of C60 into the grafolds. Intercalation or functionalization of the chemically reactive folds further expands grafold's mechanical, chemical, optical, and electronic diversity.Comment: 29 pages, 10 figures (accepted in Phys. Rev. B

    Existence of positive solutions of a superlinear boundary value problem with indefinite weight

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    We deal with the existence of positive solutions for a two-point boundary value problem associated with the nonlinear second order equation u+a(x)g(u)=0u''+a(x)g(u)=0. The weight a(x)a(x) is allowed to change its sign. We assume that the function g ⁣:[0,+[Rg\colon\mathopen{[}0,+\infty\mathclose{[}\to\mathbb{R} is continuous, g(0)=0g(0)=0 and satisfies suitable growth conditions, so as the case g(s)=spg(s)=s^{p}, with p>1p>1, is covered. In particular we suppose that g(s)/sg(s)/s is large near infinity, but we do not require that g(s)g(s) is non-negative in a neighborhood of zero. Using a topological approach based on the Leray-Schauder degree we obtain a result of existence of at least a positive solution that improves previous existence theorems.Comment: 12 pages, 4 PNG figure

    Density-potential mappings in quantum dynamics

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    In a recent letter [Europhys. Lett. 95, 13001 (2011)] the question of whether the density of a time-dependent quantum system determines its external potential was reformulated as a fixed point problem. This idea was used to generalize the existence and uniqueness theorems underlying time-dependent density functional theory. In this work we extend this proof to allow for more general norms and provide a numerical implementation of the fixed-point iteration scheme. We focus on the one-dimensional case as it allows for a more in-depth analysis using singular Sturm-Liouville theory and at the same time provides an easy visualization of the numerical applications in space and time. We give an explicit relation between the boundary conditions on the density and the convergence properties of the fixed-point procedure via the spectral properties of the associated Sturm-Liouville operator. We show precisely under which conditions discrete and continuous spectra arise and give explicit examples. These conditions are then used to show that in the most physically relevant cases the fixed point procedure converges. This is further demonstrated with an example.Comment: 20 pages, 8 figures, 3 table

    Resolving spin, valley, and moir\'e quasi-angular momentum of interlayer excitons in WSe2/WS2 heterostructures

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    Moir\'e superlattices provide a powerful way to engineer properties of electrons and excitons in two-dimensional van der Waals heterostructures. The moir\'e effect can be especially strong for interlayer excitons, where electrons and holes reside in different layers and can be addressed separately. In particular, it was recently proposed that the moir\'e superlattice potential not only localizes interlayer exciton states at different superlattice positions, but also hosts an emerging moir\'e quasi-angular momentum (QAM) that periodically switches the optical selection rules for interlayer excitons at different moir\'e sites. Here we report the observation of multiple interlayer exciton states coexisting in a WSe2/WS2 moir\'e superlattice and unambiguously determine their spin, valley, and moir\'e QAM through novel resonant optical pump-probe spectroscopy and photoluminescence excitation spectroscopy. We demonstrate that interlayer excitons localized at different moir\'e sites can exhibit opposite optical selection rules due to the spatially-varying moir\'e QAM. Our observation reveals new opportunities to engineer interlayer exciton states and valley physics with moir\'e superlattices for optoelectronic and valleytronic applications
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