Gerechtigkeit in flexiblen Arbeits- und Managementprozessen

Engels G, Maier GW, Ötting SK, Steffen E, Teetz A. Gerechtigkeit in flexiblen Arbeits- und Managementprozessen. In: Wischmann S, Hartmann EA, eds. Zukunft der Arbeit. Eine praxisnahe Betrachtung. Autonomik Industrie 4.0. Berlin: Springer Vieweg; 2018: 221-231

Quantum magnetism in two dimensions: From semi-classical N\'eel order to magnetic disorder

This is a review of ground-state features of the s=1/2 Heisenberg antiferromagnet on two-dimensional lattices. A central issue is the interplay of lattice topology (e.g. coordination number, non-equivalent nearest-neighbor bonds, geometric frustration) and quantum fluctuations and their impact on possible long-range order. This article presents a unified summary of all 11 two-dimensional uniform Archimedean lattices which include e.g. the square, triangular and kagome lattice. We find that the ground state of the spin-1/2 Heisenberg antiferromagnet is likely to be semi-classically ordered in most cases. However, the interplay of geometric frustration and quantum fluctuations gives rise to a quantum paramagnetic ground state without semi-classical long-range order on two lattices which are precisely those among the 11 uniform Archimedean lattices with a highly degenerate ground state in the classical limit. The first one is the famous kagome lattice where many low-lying singlet excitations are known to arise in the spin gap. The second lattice is called star lattice and has a clear gap to all excitations. Modification of certain bonds leads to quantum phase transitions which are also discussed briefly. Furthermore, we discuss the magnetization process of the Heisenberg antiferromagnet on the 11 Archimedean lattices, focusing on anomalies like plateaus and a magnetization jump just below the saturation field. As an illustration we discuss the two-dimensional Shastry-Sutherland model which is used to describe SrCu2(BO3)2.Comment: This is now the complete 72-page preprint version of the 2004 review article. This version corrects two further typographic errors (three total with respect to the published version), see page 2 for detail

Readjusting Our Sporting Sites/Sight: Sportification and the Theatricality of Social Life

This paper points out the potential of using sport for the analysis of society. Cultivated human movement is a specific social and cultural subsystem (involving sport, movement culture and physical culture), yet it becomes a part of wider social discourses by extending some of its characteristics into various other spheres. This process, theorised as sportification, provides as useful concept to examine the permeation of certain phenomena from the area of sport into the social reality outside of sport. In this paper, we investigate the phenomena of sportification which we parallel with visual culture and spectatorship practices in the Renaissance era. The emphasis in our investigation is on theatricality and performativity; particularly, the superficial spectator engagement with modern sport and sporting spectacles. Unlike the significance afforded to visualisation and deeper symbolic interpretation in Renaissance art, contemporary cultural shifts have changed and challenged the ways in which the active and interacting body is positioned, politicised, symbolised and ultimately understood. We suggest here that the ways in which we view sport and sporting bodies within a (post)modern context (particularly with the confounding amalgamations of signs and symbols and emphasis on hyper-realities) has invariably become detached from sports' profound metaphysical meanings and resonance. Subsequently, by emphasising the associations between social theatrics and the sporting complex, this paper aims to remind readers of ways that sport—as a nuanced phenomenon—can be operationalised to help us to contemplate questions about nature, society, ourselves and the complex worlds in which we live

Optisch nichtlineare organische Materialien mit neuen Chromophoren fuer nachrichtentechnische Anwendungen Abschlussbericht

This project should proove the applicability of NLO-polymers for the fabricaton of optical components for communication systems. As compared to LiNbO_3 polymers should allow simpler fabrication, the use of large substrates of various materials and a flexible tailoring for different applications. Last, but not least, a higher efficiency has been expected. Within this project numerous NLO-polymers have been characterized in terms of their optical and electro-optical data. This should allow the development of a NLO-polyer fulfilling the requirements of an optical switch. Different chromophores have been investigated and some efficient chromophores could be identified. Also polymers with sufficient low losses and high glass temperature have been found. The result of this project are a NLO-polymer with a high efficiency and another with low losses, but each with an insufficient glass temperature, and a NLO-polymer with a high glass temperature and a small efficiency. However, no material has been available fulfilling all the requirements for system applications in terms of efficiency, stability, and optical losses. This project and the results of other works have shown that still a considerable progress of the material development has to be achieved in order to allow the commerical application of NLO-polymers. (orig.)Available from TIB Hannover: F95B1631+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman

Material- und Technologieentwicklung fuer nachrichtentechnische Komponenten auf der Basis von SiO_2-Wellenleitern Abschlussbericht

Main task of the project was the development of a material base for integrated-optical components which combine passive as well as active functions. For the realisation of a lossless optical splitter the splitter itself and a 0.98/1.53 #mu#m wavelength multiplexer for the in- and outcoupling of the pumping light as the passive function and the planar optical amplifier as the active function was chosen. As basic materials SiO_2 and Al_2O_3 were under evaluation which were deposited by flamehydrolysis deposition (FHD) and plasma enhanced chemical vapour deposition (PECVD). For singlemode operation buried SiO_2 waveguides and strip loaded Al_2O_3 waveguides were used. The material quality is mainly described by the optical loss which was optimised to <0.1 dB/cm for silica waveguides and to <0.2 dB/cm for Al_2O_3 waveguides in the wavelength range for telecom applications (1,3 #mu#m to 1,5 #mu#m). Homogeneity and reproducibility of the silica process is well suited for the realisation of complex integrated components. Splitters with splitting ratios of 1:4 to 1:16 were realised with low insertion loss. The 0.98/1.53 #mu#m wavelength multiplexers showed an excellent 20 dB bandwidth of 111 nm for the signal light. The development of the planar optical amplifier in SiO_2 and Al_2O_3 led to fluorescence lifetimes of 8 ms resp. 7 ms. The maximum signal gain was 19 dB, but no net gain was achieved due to high material loss in Er-doped system. (orig.)SIGLEAvailable from TIB Hannover: F00B183+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung und Forschung (BMBF), Bonn (Germany)DEGerman

Thermo-optic 1*2- and 1*8-vertical coupled switches (VCS) using hybrid polymer/silica integration technology

Thermo-optic 1*2-vertical coupled switches (VCS) were fabricated using a polymer/ silica integration technology. The switches exhibited low insertion loss (<1.5 dB), low crosstalk (<-32 dB), low switching power ( 80 mW), and polarisation independence. Based on this building block, a 1*8-VCS has been demonstrated