@article{64687, author = {{Glöckner, Helge}}, issn = {{0023-608X}}, journal = {{Journal of Mathematics of Kyoto University}}, keywords = {{46G20, 26E05, 26E15, 26E20, 46T25}}, number = {{3}}, pages = {{631–642}}, title = {{{Instructive examples of smooth, complex differentiable and complex analytic mappings into locally convex spaces}}}, doi = {{10.1215/kjm/1250281028}}, volume = {{47}}, year = {{2007}}, } @article{64689, author = {{Glöckner, Helge}}, issn = {{1370-1444}}, journal = {{Bulletin of the Belgian Mathematical Society - Simon Stevin}}, keywords = {{26E30, 26E20, 46A16, 46G05, 46S10}}, number = {{5}}, pages = {{877–904}}, title = {{{Comparison of some notions of C^k-maps in multi-variable non-archimedian analysis}}}, volume = {{14}}, year = {{2007}}, } @article{64686, author = {{Glöckner, Helge and Willis, George A.}}, issn = {{0146-4124}}, journal = {{Topology Proceedings}}, keywords = {{22D45, 22D05, 20G25, 22E15, 22E35}}, number = {{2}}, pages = {{481–501}}, title = {{{Directions of automorphisms of Lie groups over local fields compared to the directions of Lie algebra automorphisms}}}, volume = {{31}}, year = {{2007}}, } @article{64688, author = {{Glöckner, Helge}}, issn = {{0949-5932}}, journal = {{Journal of Lie Theory}}, keywords = {{22A05, 22E20, 22E65}}, number = {{4}}, pages = {{899–902}}, title = {{{Simplified proofs for the pro-Lie group theorem and the one-parameter subgroup lifting lemma}}}, volume = {{17}}, year = {{2007}}, } @article{66784, abstract = {{The link between formal education and national identities is widely acknowledged. Empirical research on national and supranational identities of teachers, however, is still relatively rare. Whilst a number of studies consider the special population of teachers, these contributions do not consistently focus on national and supranational identities. Based on a case study of 72 trainee teachers from Baden‐Württemberg (Germany), the present paper looks at the reconcilability of national and European identities and explores notions of the European Union in terms of cultural and geographical inclusiveness. Findings on the case study level are considered in their own right, but also compared to findings on the regional, national and European level, using relevant Eurobarometer survey data. The article shows that high levels of attachment to nation and high levels of attachment to Europe do not have to be mutually exclusive. It also demonstrates that, for most trainee teachers, the European Union constitutes a culturally and geographically inclusive institution that is supposed to stand for cultural diversity, peace, freedom and respect of human rights. Through comparisons that go beyond the case study level, the paper recognises the importance of regional and national contexts. Nonetheless, it argues that some of its findings are likely to be relevant for studies of national and European identities across different European societies.}}, author = {{Pöllmann, Andreas}}, issn = {{0305-7925}}, journal = {{Compare: A Journal of Comparative and International Education}}, number = {{1}}, pages = {{89--104}}, publisher = {{Informa UK Limited}}, title = {{{National and European identities: Notions of reconcilability and inclusiveness in a case study of German trainee teachers}}}, doi = {{10.1080/03057920601061844}}, volume = {{37}}, year = {{2007}}, } @article{9533, abstract = {{The design of piezoelectric transducers is usually based on single-objective optimization only. In most practical applications of piezoelectric transducers, however, there exist multiple design objectives that often are contradictory to each other by their very nature. It is impossible to find a solution at which each objective function gets its optimal value simultaneously. Our design approach is to first find a set of Pareto-optimal solutions, which can be considered to be best compromises among multiple design objectives. Among these Pareto-optimal solutions, the designer can then select the one solution which he considers to be the best one. In this paper we investigate the optimal design of a Langevin transducer. The design problem is formulated mathematically as a constrained multiobjective optimization problem. The maximum vibration amplitude and the minimum electrical input power are considered as optimization objectives. Design variables involve continuous variables (dimensions of the transducer) and discrete variables (the number of piezoelectric rings and material types). In order to formulate the optimization problem, the behavior of piezoelectric transducers is modeled using the transfer matrix method based on analytical models. Multiobjective evolutionary algorithms are applied in the optimization process and a set of Pareto-optimal designs is calculated. The optimized results are analyzed and the preferred design is determined. }}, author = {{Fu, Bo and Hemsel, Tobias and Wallaschek, Jörg}}, issn = {{0041-624X}}, journal = {{Ultrasonics}}, keywords = {{Piezoelectric transducer}}, pages = {{e747 -- e752}}, title = {{{Piezoelectric transducer design via multiobjective optimization}}}, doi = {{10.1016/j.ultras.2006.05.087}}, volume = {{44, Supplement}}, year = {{2006}}, } @inbook{9536, abstract = {{This paper presents a model for unsteady longitudinal slippage of a loaded rubber wheel. The aim of modelling was to calculate the dynamical contact behavior in a numerical efficient way. Further on, simulation results are compared to experimental data.}}, author = {{Gutzeit, F and Sextro, Walter and Kröger, Matthias}}, booktitle = {{Analysis and Simulation of Contact Problems}}, editor = {{Wriggers, Peter and Nackenhorst, Udo}}, isbn = {{978-3-540-31760-9}}, pages = {{261--270}}, publisher = {{Springer Berlin Heidelberg}}, title = {{{Unsteady rolling contact of rubber wheels}}}, doi = {{10.1007/3-540-31761-9_29}}, volume = {{27}}, year = {{2006}}, } @article{9539, abstract = {{Classically, rotary motors with gears and spindle mechanisms are used to achieve translatory motion. In means of miniaturization and weight reduction piezoelectric linear motors are of interest. Several ultrasonic linear motors found in literature base on the use of two different vibration modes. Most often flexural and longitudinal modes are combined to achieve an elliptic micro-motion of surface points. This micro-motion is converted to direct linear (or translatory) motion of a driven slider. To gain high amplitudes of the micro-motion and thus having a powerful motor, the ultrasonic vibrator should be driven near the eigenfrequency of its modes. Additionally, low mechanical and electrical losses lead to increased efficiency and large amplitude magnification in resonance. This demands a geometrical design that fits the eigenfrequencies of the two different modes. A frequency-deviation of only a few percent leads to non-acceptable disturbance of the elliptical motion. Thus, the mechanical design of the vibrators has to be done very carefully. Within this contribution we discuss different motor designs based on the coupling of two the same longitudinal vibrations within one structure to generate an elliptic motion of surface points. Different concepts based on piezoelectric plates and Langevin transducers are compared. Benefits and drawbacks against the combination of longitudinal and bending modes will be discussed. Numerical results of the stator vibration as well as motor characteristics are validated by measurements on different prototypes. }}, author = {{Hemsel, Tobias and Mracek, Maik and Twiefel, Jens and Vasiljev, Piotr}}, issn = {{0041-624X}}, journal = {{Ultrasonics}}, keywords = {{Piezoelectric linear motor}}, pages = {{e591 -- e596}}, title = {{{Piezoelectric linear motor concepts based on coupling of longitudinal vibrations}}}, doi = {{10.1016/j.ultras.2006.05.056}}, volume = {{44, Supplement}}, year = {{2006}}, } @inproceedings{9540, author = {{Hemsel, Tobias and Priya, S}}, booktitle = {{Proceedings of 2nd International Workshop on Piezoelectric Materials and Applications in Actuators}}, number = {{Band 180}}, pages = {{223--228}}, title = {{{Model Based Analysis of Piezoelectric Transformers}}}, year = {{2006}}, } @article{9541, abstract = {{Piezoelectric transformers are increasingly getting popular in the electrical devices owing to several advantages such as small size, high efficiency, no electromagnetic noise and non-flammable. In addition to the conventional applications such as ballast for back light inverter in notebook computers, camera flash, and fuel ignition several new applications have emerged such as AC/DC converter, battery charger and automobile lighting. These new applications demand high power density and wide range of voltage gain. Currently, the transformer power density is limited to $40 W/cm{^3}$ obtained at low voltage gain. The purpose of this study was to investigate a transformer design that has the potential of providing higher power density and wider range of voltage gain. The new transformer design utilizes radial mode both at the input and output port and has the unidirectional polarization in the ceramics. This design was found to provide 30 W power with an efficiency of 98\% and 30 $\,^{\circ}$C temperature rise from the room temperature. An electro-mechanical equivalent circuit model was developed to describe the characteristics of the piezoelectric transformer. The model was found to successfully predict the characteristics of the transformer. Excellent matching was found between the computed and experimental results. The results of this study will allow to deterministically design unipoled piezoelectric transformers with specified performance. It is expected that in near future the unipoled transformer will gain significant importance in various electrical components.}}, author = {{Hemsel, Tobias and Priya, S}}, issn = {{0041-624X}}, journal = {{Ultrasonics}}, keywords = {{Piezoelectric transformers}}, pages = {{e741 -- e745}}, title = {{{Model based analysis of piezoelectric transformers}}}, doi = {{10.1016/j.ultras.2006.05.086}}, volume = {{44, Supplement}}, year = {{2006}}, } @article{9543, abstract = {{An improved concept for ultrasonic hyperthermia of tumors is presented. This concept is based on past experience of a German government supported project [1], which ended in 1984. It offers a low cost alternative to common RF- and microwave methods for hyperthermia of tumors with volumes between 1 and 40 ml at treatment times between 30 and 60 min. Our new version of the system considerably improves the temperature suppression in the healthy tissue around the target area and enables the adjustment of the beam width to the actual tumor size and the field geometry to the depth and shape of the tumor. The applicator can be used for moderate hyperthermia with tissue overheating up to 10 K or for ablation therapy with short high temperature pulses. Its central area is free for the integration of a commercial ultrasonic diagnostic sector scanner or a Doppler flow sensor in order to support the adjustment of the transducer and to monitor the whole area during the therapy.}}, author = {{Lierke, E.G. and Hemsel, Tobias}}, issn = {{0041-624X}}, journal = {{Ultrasonics}}, keywords = {{Moderate hyperthermia}}, pages = {{e341 -- e344}}, title = {{{Focusing cross-fire applicator for ultrasonic hyperthermia of tumors}}}, doi = {{10.1016/j.ultras.2006.07.004}}, volume = {{44, Supplement}}, year = {{2006}}, } @article{9546, abstract = {{Rotary ultrasonic motors have found broad industrial application in camera lens drives and other systems. Linear ultrasonic motors in contrast have only found limited applications. The main reason for the limited range of application of these very attractive devices seems to be their small force and power range. Attempts to build linear ultrasonic motors for high forces and high power applications have not been truly successful yet. To achieve larger force and higher power, multiple miniaturized motors can be combined. This approach, however, is not as simple as it appears at first glance. The electromechanical behaviour of the individual motors differs slightly due to manufacturing and assembly tolerances. The individual motor characteristics are strongly dependent on the driving parameters (frequency, voltage, temperature, pre-stress, etc.) and the driven load and the collective behaviour of the swarm of motors is not just the linear superposition of the individual drive's forces. Thus, the bundle of motors has to be synchronized and controlled appropriately in order to obtain an optimized drive that is not oversized and costly. We have investigated driving and control strategies of a set of linear ultrasonic motors. Our contribution will be divided into three main parts. In part I ultrasonic linear motors will be introduced. In part II driving strategies for a single motor as well as for a bundle of motors will be presented. These concepts will be verified by simulation results and experimental data. In part III a simplified model for the motor's electromechanical behaviour will be given.}}, author = {{Mracek, Maik and Hemsel, Tobias}}, issn = {{0041-624X}}, journal = {{Ultrasonics}}, keywords = {{Ultrasonic linear motor}}, pages = {{e597 -- e602}}, title = {{{Synergetic driving concepts for bundled miniature ultrasonic linear motors}}}, doi = {{10.1016/j.ultras.2006.05.201}}, volume = {{44, Supplement}}, year = {{2006}}, } @article{9547, author = {{Mracek, Maik and Vasiljev, Piotr and Hemsel, Tobias and Wallaschek, Jörg}}, journal = {{Solid State Phenomena}}, pages = {{167--172}}, publisher = {{Trans Tech Publ}}, title = {{{Self configuration of a novel miniature ultrasonic linear motor}}}, volume = {{113}}, year = {{2006}}, } @inproceedings{9548, abstract = {{This paper presents a general model based on the electromechanical circuit theory. The model is set up as a mechanical equivalent model for base excited systems and describes the behaviour of a piezoelectric element around one resonance frequency which is sufficient for most practical applications. The model is extended to obtain the influence of geometrical and material properties. The derivated properties are used to describe the parameters of the general model which is easy to handle. Using this model either the calculation of the output power on a specific electric load or the determination of the design of the used piezoelectric element for a needed electric output power is possible. The paper focuses on the design of the ratio of length and width of a piezoelectric bimorph. The validity of the model is shown by the comparison of computed and experimental results.}}, author = {{Richter, Björn and Twiefel, Jens and Hemsel, Tobias and Wallaschek, Jörg}}, booktitle = {{ASME 2006 International Mechanical Engineering Congress and Exposition}}, keywords = {{Materials properties, Design, Generators}}, title = {{{Model based design of piezoelectric generators utilizing geometrical and material properties}}}, doi = {{doi:10.1115/IMECE2006-14862}}, year = {{2006}}, } @article{9550, author = {{Schiedeck, Florian and Hemsel, Tobias and Wallaschek, Jörg}}, journal = {{Solid State Phenomena}}, pages = {{195--198}}, publisher = {{Trans Tech Publ}}, title = {{{The use of shape memory alloy wires in actuators}}}, volume = {{113}}, year = {{2006}}, } @article{18597, abstract = {{We propose a new method for calculating optical defect levels and thermodynamic charge-transition levels of point defects in semiconductors, which includes quasiparticle corrections to the Kohn-Sham eigenvalues of density-functional theory. Its applicability is demonstrated for anion vacancies at the (110) surfaces of III–V semiconductors. We find the (+/0) charge-transition level to be 0.49 eV above the surface valence-band maximum for GaAs(110) and 0.82 eV for InP(110). The results show a clear improvement over the local-density approximation and agree closely with an experimental analysis.}}, author = {{Hedström, Magnus and Schindlmayr, Arno and Schwarz, Günther and Scheffler, Matthias}}, issn = {{1079-7114}}, journal = {{Physical Review Letters}}, number = {{22}}, publisher = {{American Physical Society}}, title = {{{Quasiparticle corrections to the electronic properties of anion vacancies at GaAs(110) and InP(110)}}}, doi = {{10.1103/PhysRevLett.97.226401}}, volume = {{97}}, year = {{2006}}, } @article{18599, abstract = {{This paper investigates the influence of the basis set on the GW self-energy correction in the full-potential linearized augmented-plane-wave (LAPW) approach and similar linearized all-electron methods. A systematic improvement is achieved by including local orbitals that are defined as second and higher energy derivatives of solutions to the radial scalar-relativistic Dirac equation and thus constitute a natural extension of the LAPW basis set. Within this approach linearization errors can be eliminated, and the basis set becomes complete. While the exchange contribution to the self-energy is little affected by the increased basis-set flexibility, the correlation contribution benefits from the better description of the unoccupied states, as do the quasiparticle energies. The resulting band gaps remain relatively unaffected, however; for Si we find an increase of 0.03 eV.}}, author = {{Friedrich, Christoph and Schindlmayr, Arno and Blügel, Stefan and Kotani, Takao}}, issn = {{1550-235X}}, journal = {{Physical Review B}}, number = {{4}}, title = {{{Elimination of the linearization error in GW calculations based on the linearized augmented-plane-wave method}}}, doi = {{10.1103/physrevb.74.045104}}, volume = {{74}}, year = {{2006}}, } @article{28093, author = {{van Ophuysen, Stefanie and Bloh, Bea and Schürer, Sina}}, journal = {{Forum Schule}}, number = {{4}}, pages = {{10--11}}, title = {{{Wie Schülerinnen und Schüler den Wechsel von der Grundschule zur weiterführenden Schule erleben – ein Zwischenbericht.}}}, year = {{2006}}, } @inbook{28173, author = {{Bloh, Bea and Schürer, Sina}}, booktitle = {{Risikofaktoren kindlicher Entwicklung. Migration, leistungsbezogene Emotionen und der Übergang von der Grundschulzeit zu den weiterführenden Schulen}}, editor = {{Schründer-Lenzen, A.}}, pages = {{208--222}}, publisher = {{VS Verlag}}, title = {{{Veränderung der Schulfreude von der Grundschule zur weiterführenden Schule}}}, year = {{2006}}, } @inbook{28172, author = {{Schürer, Sina and Bloh, Bea and van Ophuysen, Stefanie}}, booktitle = {{Professionelles Handeln in der Grundschule: Entwicklungslinien und Forschungsbefunde}}, editor = {{Hinz, R. and Pütz, T.}}, pages = {{90--96}}, publisher = {{Schneider Verlag Johengehren}}, title = {{{Übergangsgestaltung durch schulstufenübergreidende Lehrerkooperation}}}, year = {{2006}}, }