15 Fakultätsübergreifend / Sonstige Einrichtung
Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/16
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Item Open Access Item Open Access Philosophy of action and Its relationship to interactive visualisation and Molière’s theatre(2023) Feige, Daniel M.; Weiskopf, Daniel; Dickhaut, KirstenItem Open Access Zero bias anomalies in point-contact characteristics of αt-(BEDT-TTF)2I3(1994) Ernst, Gabriele; Nowack, Andreas; Weger, Meir; Schweitzer, DieterThe zero-bias anomaly in point-contact characteristics of the organic superconductor α-(BEDT-TTF)2I3 is investigated as a function of temperature and magnetic field. It is found that the zero-bias anomaly is insensitive to magnetic fields up to 5 T. In contrast, a structure at 5 meV, conventionally designated as the superconducting gap - but which is 4 times larger than the expected BCS gap - is strongly affected by magnetic fields above 1 T.Item Open Access Electrooptical investigation on the three switching states of a chiral smectic side group polymer(1992) Gießelmann, Frank; Zugenmaier, Peter; Scherowsky, Günter; Kühnpast, Kurt; Springer, JürgenElectrooptical properties of a polyacrylate with 1,3-dioxolane-4-carboxylic acid as chiral building block terminally attached to phenylpyridine mesogenic moiety and linked via a C11 spacer were studied. Results showed that the formation of 3 switching states for the polymer occurred upon conformational interactions between the side groups and the main chain.Item Open Access Lattice dynamics of 3-dimensional tilings modelling icosahedral quasicrystals(1993) Los, Joop; Janssen, Ted; Gähler, FranzA study of the lattice dynamics of three-dimensional tilings modelling icosahedral quasicrystals is presented. The phonon density of states is calculated, and the character of the eigenstates is determined. Three different types of commensurate approximants are considered, namely symmetrized, perfect and randomized approximants. It appears that the density of states is smoothed by randomization. The participation ratio, which measures the rate of localization of an eigenmode, is given as a function of frequency. Only the states at the very upper end of the frequency spectrum appear to be localized, whereas all other states are extended. The density of states at low frequencies is analyzed in more detail, by applying a Brillouin zone integration over the lowest branches. It is found that these lowest branches scale for successive approximants.Item Open Access Prüfgerechter Entwurf und Test hochintegrierter Schaltungen(1992) Wunderlich, Hans-Joachim; Schulz, Michael H.Der Beitrag gibt einen Überblick über die wichtigsten praxisrelevanten Teststrategien, wobei unter einer Teststrategie nicht nur die Verfahren zur Testsatzerzeugung und zur eigentlichen Testdurchführung, sondern auch das zugrunde liegende Fehlermodell und die erforderlichen testfreundlichen Entwurfsmaßnahmen, die die Voraussetzung für die Anwendung dieser Verfahren darstellen, zu verstehen sind. Es werden die gängigsten Methoden zum konventionellen externen Test vorgestellt und bewertet sowie das Prinzip der immer breitere Anwendung findenden Selbsttestmethoden und ihre Vorteile erläutert. Nach einem kurzen Ausblick auf die Fortschritte, die Verfahren zur automatischen Synthese testbarer Schaltungen erhoffen lassen, werden schließlich Aspekte des Systemtests und insbesondere das Boundary-Scan-Prinzip und die damit verbundenen Vorteile diskutiert.Item Open Access The social amplification of risk : theoretical foundations and empirical applications(1992) Renn, Ortwin; Burns, William J.; Kasperson, Jeanne X.; Kasperson, Roger E.; Slovic, PaulThe article presents the framework of social amplification of risk which integrates the technical assessment and the social experience of risk. Risk perception research has revealed that contextual factors shape individual risk estimations and evaluations. Identification of these factors, such as voluntariness, personal ability to influence risks, familiarity with the hazard, and catastrophic potential, provides useful information about the elements that individuals consider in constructing their interpretation of risks. In addition, analyses of people's heuristics in making inferences have shed some light on how risk information is generalized and evaluated intuitively. These psychological studies fail to explain, however, why individuals attend to certain characteristics of risks and ignore others. Furthermore, in focusing only on the individual as an information processor, these studies exclude from the analysis the social and cultural variance of risk interpretations. The social amplification framework postulates that the social and economic impacts of an adverse event are determined not only by the direct physical consequences of the event, but by the interaction of psychological, cultural, social, and institutional processes that amplify or attenuate public experience of risk and result in secondary impacts.Item Open Access Fluid flow and heat transfer in an axially rotating pipe subjected to external convection(1992) Weigand, Bernhard; Beer, HansThe effects of external insulation and tube rotation on the heat transfer to a fluid flowing inside a tube are examined by analysis. The turbulent flow is assumed to be hydrodynamically fully developed. Heat transfer was found to be strongly suppressed by tube rotation. It is shown that the significance of external insulation on the Nusselt number increases with growing rotation rate of the pipe.Item Open Access Electric field induced domain formation in surface stabilized ferroelectric liquid crystal cells(1994) Dierking, Ingo; Gießelmann, Frank; Schacht, Jochen; Zugenmaier, PeterTwo types of domains have been observed for S sub(C) ferroelectric liquid crystals in surface stabilized cells (SSFLC) by application of a high electric field with the smectic layers tilted by the amount of the chevron angle with respect to the normal of the rubbing direction in the substrate plane. The layer structure resembles that of a chevron configuration in the plane of the substrate similar to the recently reported stripe-shaped SSFLC structure. The two domain types 'appear' to switch in a reciprocal fashion when applying an AC electric field and observed between crossed polarizers. The temperature dependence of this effect has been investigated and an explanation proposed analogous to a striped texture model.Item Open Access Signal fidelity requirements for deriving impedance cardiographic measures of cardiac function over a broad heart rate range(1993) Hurwitz, Barry E.; Shyu, Liang-Yu; Lu, Chih-Cheng; Reddy, Sridhar P.; Schneiderman, Neil; Nagel, Joachim H.Our findings indicate that the impedance cardiogram spectrum extends from DC to 50 Hz. Any amplifier with an upper band limit less than 50 Hz can be expected to produce attenuation and distortion of the impedance cardiogram. This signal attenuation may be systematically enhanced under conditions of high heart rate when a greater proportion of signal energy will be in the upper frequency range of the impedance cardiogram spectrum. Therefore, the present study was designed to assess the influence of amplifier bandwidth on dZ/dtmax, stroke volume, and systolic time intervals (LVET, PEP, QZ, QX). Simultaneously measured ΔZ and dZ/dt signals from two impedance cardiographs, with corner frequencies of 120 and 60 Hz for the ΔZ and 50 and 15 Hz for dZ/dt channels, were contrasted over a broad range of heart rate (70–150 bpm). In addition to the analog dZ/dt signals obtained from the instruments, the ΔZ signals were digitally converted to dZ/dt by off-line digital differentiation with a 50 Hz corner frequency. The results demonstrated that the measurements with the 15 Hz corner frequency, when compared with the 50 Hz corner frequency measurements, systematically attenuated the dZ/dtmax amplitude and stroke volume measurements as heart rate increased. The attenuation of dZ/dtmax and stroke volume ranged from about 13% to 26% as heart rate increased from 70 to 150 bpm. When the upper bandlimit was 50 Hz, the dZ/dt signal had greater resolution of waveform events and produced less prolonged systolic time intervals. The 15 Hz amplifier differentially influenced the B point, Z-peak and X minimum, having no apparent effect on the temporal location of the B point, but delaying the Z-peak about 21.7 ms and the X minimum about 7.4 ms. These findings indicate that impedance cardiographs with insufficient upper bandlimits will differentially influence ICG-derived measurements as heart rate varies.