Thomas Schulte - Academia.edu (original) (raw)

Papers by Thomas Schulte

Information Assurance and Security, 1997

An optimized control scheme for the most advanced traveling wave type ultrasonic motor powered by... more An optimized control scheme for the most advanced traveling wave type ultrasonic motor powered by a resonant power converter is presented and verified by measurements on a prototype drive. Basing on an averaged drive model, which reflects the slow dynamic behavior of the drive's ultrasonic oscillations by time varying fundamental Fourier coefficients, a cascaded two-phase vector control scheme is designed.

at - Automatisierungstechnik, 2015

The extension of microelectronics to new frontiers that include MEMS, nanotechnology, flexible el... more The extension of microelectronics to new frontiers that include MEMS, nanotechnology, flexible electronics, biotechnology, energy and solid state lighting is inevitable. Development of a necessary multi faceted work force is critical to o ur nation's innovation edge in these fields. The department of Microelectronic Engineering at Rochester Institute of Technology received a NSF implementation grant in 2005 to institute a

IEEE/ASME International Conference on Advanced Intelligent Mechatronics, 1999

A novel speed control for traveling wave type ultrasonic motors is presented and verified by meas... more A novel speed control for traveling wave type ultrasonic motors is presented and verified by measurements on a prototype drive, Based on an underlying bending wave control the nonlinear torque generation of the USM is compensated by an inverse contact model calculating the reference values of bending wave control under consideration of an optimized set point adjustment. For this task

IEEE-ASME Transactions on Mechatronics, 2000

A complete model-based control for traveling-wave-type ultrasonic motors is presented. The contro... more A complete model-based control for traveling-wave-type ultrasonic motors is presented. The control scheme consists of inner control loops with respect to the oscillation systems, offering all meaningful degrees of freedom for adjusting the traveling bending wave, and outer control loops for torque and speed. After a brief review on modeling the actuator and presentation of a parameter identification method, the

Solid State Ionics, 2001

Application of a material with the nominal composition Gd0.7Ca0.3CoOx is considered for use as me... more Application of a material with the nominal composition Gd0.7Ca0.3CoOx is considered for use as membrane material in an exhaust gas sensor for NOx. SEM–EDX and XRD measurements revealed that after sintering at 1200°C in air, three co-existing phases are present: (Gd0.6Ca0.4)2CoOx (60 vol.%), GdCoO3 (26 vol.%) and CoO. Catalytic activities were investigated using temperature-programmed reaction (TPR). Whereas the composite Gd0.7Ca0.3CoOx shows no catalytic activity towards NOx reduction, as required in the targeted application, the single phase components (Gd0.6Ca0.4)2CoOx and GdCoO3, were found both to be active. The permeation rates exhibited by the composite material, at 1000°C, are considered too low for real application of this material. Oxygen permeation rates through perovskite-structured GdCoO3−δ and (Gd0.6Ca0.4)2CoO4−δ, having the K2NiF4-structure, were found to be below the range of detection (<10−11 mol/cm2 s).

Physical Review Letters, 2008

We propose and analyze a general mechanism of disorder-induced order in two-component Bose-Einste... more We propose and analyze a general mechanism of disorder-induced order in two-component Bose-Einstein condensates, analogous to corresponding effects established for XY spin models. We show that a random Raman coupling induces a relative phase of π/2 between the two BECs and that the effect is robust. We demonstrate it in 1D, 2D and 3D at T = 0 and present evidence that it persists at small T > 0. Applications to phase control in ultracold spinor condensates are discussed.

Physical Review Letters, 2003

We measure the intensity correlation function of two interfering spatially displaced copies of a ... more We measure the intensity correlation function of two interfering spatially displaced copies of a phase fluctuating Bose-Einstein Condensate (BEC). It is shown that this corresponds to a measurement of the phase correlation properties of the initial condensate. Analogous to the method used in the stellar interferometer experiment of Hanbury Brown and Twiss, we use spatial intensity correlations to determine the phase coherence lengths of elongated BECs. We find good agreement with our prediction of the correlation function and confirm the expected coherence length.

Physical Review A, 2003

The coherence properties of phase fluctuating Bose-Einstein condensates are studied both theoreti... more The coherence properties of phase fluctuating Bose-Einstein condensates are studied both theoretically and experimentally. We derive a general expression for the N -particle correlation function of a condensed Bose gas in a highly elongated trapping potential. The second order correlation function is analyzed in detail and an interferometric method to directly measure it is discussed and experimentally implemented. Using a Bragg diffraction interferometer, we measure intensity correlations in the interference pattern generated by two spatially displaced copies of a parent condensate. Our experiment demonstrates how to characterize the second order correlation function of a highly elongated condensate and to measure its phase coherence length.

Physical Review A, 2008

We present a detailed analysis of the dynamics of Bloch oscillations of Bose-Einstein condensates... more We present a detailed analysis of the dynamics of Bloch oscillations of Bose-Einstein condensates in disordered lattice potentials. Due to the disorder and the interparticle interactions these oscillations undergo a dephasing, reflected in a damping of the center of mass oscillations, which should be observable under realistic experimental conditions. The interplay between interactions and disorder is far from trivial, ranging from an interaction-enhanced damping due to modulational instability for strong interactions, to an interaction-reduced damping due to a dynamical screening of the disorder potential.

Journal of the European Ceramic Society, 2001

Several mixed ionic–electronic conductors such as Gd1–xCaxCoO3–d (GCC) and La1–xSrxCo1–yCuyO3–d a... more Several mixed ionic–electronic conductors such as Gd1–xCaxCoO3–d (GCC) and La1–xSrxCo1–yCuyO3–d as well as composite materials like Gd1–xCaxCoO3–d / Ce1–xGdxO2–d (GCCCGO) have been investigated with respect to their use as highly selective membranes within a new amperometric sensor system. Materials characterisation was carried out concerning surface reactions of the membranes, thermal expansion, and electronic as well as oxygen permeation properties. Taking

Applied Physics B: Lasers and Optics, 2003

Quasi one dimensional Bose-Einstein condensates (BECs) in elongated traps exhibit significant pha... more Quasi one dimensional Bose-Einstein condensates (BECs) in elongated traps exhibit significant phase fluctuations even at very low temperatures. We present recent experimental results on the dynamic transformation of phase fluctuations into density modulations during time-of-flight and show the excellent quantitative agreement with the theoretical prediction. In addition we confirm that under our experimental conditions, in the magnetic trap density modulations are strongly suppressed even when the phase fluctuates. The paper also discusses our theoretical results on control of the condensate phase by employing a time-dependent perturbation. Our results set important limitations on future applications of BEC in precision atom interferometry and atom optics, but at the same time suggest pathways to overcome these limitations.

Cold atomic gases placed in optical lattices enable studies of simple condensed matter theory mod... more Cold atomic gases placed in optical lattices enable studies of simple condensed matter theory models with parameters that may be tuned relatively easily. When the optical potential is randomized (e.g. using laser speckle to create a random intensity distribution) one may be able to observe Anderson localization of matter waves for non-interacting bosons, the so-called Bose glass in the presence of interactions, as well as the Fermi glass or quantum spin glass for mixtures of fermions and bosons.

ABSTRACT Der Simulation kommt im Rahmen einer durchgehenden digitalen Fabrikplanung immer größere... more ABSTRACT Der Simulation kommt im Rahmen einer durchgehenden digitalen Fabrikplanung immer größere Bedeutung zu. Eine Möglichkeit, die Qualität sowie Termintreue bei der Erstellung von automatisierten fertigungstechnischen Anlagen sicherzustellen, stellt die Absicherung des Steuerungscodes mit einer virtuellen Inbetriebnahme (VIBN) dar. Jedoch ist der für eine VIBN zwingend notwendige Modellbildungsprozess oftmals mit hohen Aufwänden verbunden, die das Einsparpotential einer VIBN oftmals übertreffen und dem Nutzen einer Simulation insgesamt entgegenstehen. Eine mögliche Lösung könnte die automatische Simulationsmodellgenerierung fertigungstechnischer Anlagen sein. Der vorliegende Beitrag zeigt, wie aus Anlagenstrukturdaten, dargestellt im objektorientiert aufgebauten Datenaustauschformat AutomationML, Simulationsmodelle fertigungstechnischer Anlagen in der objektorientierten Modellierungssprache Modelica automatisch generiert werden können. Das generierte Modell läuft anschließend auf einer auf einem Standard-PC basierenden Hardware-in-the-Loop-Plattform und wird mit der mit der realen Steuerung verbunden, so dass diese virtuell in Betrieb genommen werden kann. Beispielhaft wird die VIBN einer unstetigen Fördertechniklösung als typisches Beispiel einer fertigungstechnischen Anlage gezeigt.