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Studies conducted by R. Conrad (1970, 1973) and M. I. Posner et al (1969) led to the hypothesis that the prelingually deaf encode visually perceived verbal information on the basis of its form. To examine this hypothesis, the RTs of 19 congenitally deaf and 33 normal 9–16 yr olds were measured as the Ss compared successively presented pairs of upper- and lowercase letters. Results fail to support the hypothesis and demonstrate the importance of the effects of development and of modern education programs for the deaf on the encoding of perceived verbal materials. (French abstract) (33 ref) (PsycINFO Database Record (c) 2016 APA, all rights reserved)
Autistic symptoms become apparent at the earliest during the 2nd-3rd month of life when the spontaneous registration of the meaning of specific-visual stimuli (eyes, configuration of the mother's face) do not occur and also learning experiences by reason of mimic and gestures repeatedly shown by the interaction partner can neither evoke a social smile nor stimulate anticipational behaviour. Even with increasing age an empathetic perception of feelings in the corresponding mimical gesticular formation is very difficult and they themselves are only insufficiently able to express their own feelings intelligibly to everyone. As mimic and gestures are, however, visually perceived, the autistic perceptive child's competence is of great importance. On the basis of the examinations of visual perception (retinal pathology, tunnel vision) perceptual processing (recognition of feelings, sex and age) and the disintegration of multimodal stimuli it can be presumed that social and emotional deficits are to be seen in connection with a deviant perceptive interpretation of the world and irregular processing on the basis of a neuro-biological handicap (the absence of a genetic determined reference-system for emotionally significant stimuli), which can have various causes (comp. Gillberg 1988) and also impede the adequate expression of feelings in mimic, gestures and voice. Autistic people see, experience and understand the world in a specific way in which and by which they differ from non-handicapped people.
An analytical model for dual-gate-controlled SOI MOSFETs is presented, assuming uniformly doped p-silicon films. It is restricted to electron inversion layers and depletion regions, neglecting hole densities. It allows to account for the spatial description of electronic quantities in the silicon film. Due to the non-linearities of the semiconductor equations the model parameters must be extracted iteratively. Some applications are presented to demonstrate the usefulness of the model.
Psychotherapeutic possibilities of treating chronic pain are employed in two different ways: Firstly in the form of psychotherapy in patients whose strategies for coping with pain and/or pain genesis can be described in terms of psychopathological categories; secondly in the form of pain-coping training, which is generally indicated in the presence of chronic pain, in particular that which is traditionally termed organic. With respect to their effectiveness in achieving, in the first place, mood change, and in the assessment of symptoms, the individual procedures have been well tested. The question as to differential indication, which can most readily be applied to the use of biofeedback, remains largely unanswered.
An analytical model for the spatial distribution of potential, electric field and carrier densities is presented, assuming uniform doping density and constant quasi-Fermi potentials in the direction of modeling. Starting from the current relations a differential equation respecting two-dimensional effects is developed and solved approximately by decomposition in three regions with different preconditions: (a) flatband region, (b) constant spacecharge density and (c) strong inversion or accumulation. Inaccuracies arise mainly from violated preconditions at the interfaces between the different regions. Two-dimensional effects are respected in the analytical model of (b) only but they influence region (c) by means of boundary conditions at the interface of (b) and (c).
The investigations of this paper are focused to region (c). This part of our model is identical to the model of Hauser and Littlejohn[1]. They integrated a simplified form of the semiconductor-Poisson equation twice but were restricted to one-dimensional applications and thermal equilibrium. Our derivation allows for large electric fields and current densities perpendicular to the direction of modeling. From analytical considerations confirmed by numerical experiments we suggest preference to the gradual channel condition, with x and y defined according to Fig. 1. This definition allows the potentials to vary significantly with respect to y. We found that this holds for the quasi-Fermi potentials also. Furthermore an empirical model for the maximum width of strong-inversion layers in uniformly doped silicon films is presented in eqn (46).
Distinct electron and hole quasi-Fermi potentials, øf,n and øf,p, are included into a one-dimensional SOI MOSFET model that accounts for finite inversion and depletion layer thicknesses. The inclusion of øf,n, øf,p in the nonlinear analytical model is demonstrated to describe phenomena like kink effect and the multistable-charge-controlled-memory effect (MCCM) in SOI MOSFETs. The calculation of øf,p(t) depends on the device history and generation/recombination rates.
A one-dimensional analytical model for dual-gate-controlled SOI MOSFETs is presented and applied to a stacked p-channel MOSFET fabricated by epitaxial lateral overgrowth (ELO). The authors found and modeled a nonlinear dependence of front-gate threshold voltage on back-gate voltage if threshold is defined by a constant current instead of a constant silicon-surface potential. It is demonstrated by comparison of subthreshold slopes that surface potentials are not pinned to the onset of strong inversion or accumulation. Accurate one-dimensional modeling is a necessity for device characterization and a precondition for general SOI models for circuit simulation.< >
Angekündigte Rechtsprechungsänderungen - Die „Annunziationsjudikatur“ des Bundesarbeitsgerichts
(1992)
La présente invention concerne un circuit intermédiaire entre un circuit logique a basse tension et un étage de sortie à haute tension réalisés dans une technologie CMOS standard. L'étage de sortie (20) comporte deux transistors respectivement à canal N et à canal P, réalisés selon une technologie CMOS standard. Le circuit intermédiaire comporte un translateur de niveau de tension (21) couplé entre un circuit logique d'entrée SL et ledit étage de sortie (20). Ce translateur de niveau de tension (21) est réalisé selon une technologie CMOS standard et est constitué d'au moins deux blocs de base identiques formant des miroirs de tension interconnectés de façon croisée. Ce circuit est utilisé pour commander des transducteurs, des écrans plasma et des actionneurs électromécaniques.
A family of CMOS low- to high-voltage output interface circuits based on a standard, unmodified low-voltage CMOS technology is described. Using only thin-oxide high-voltage (HV) devices with reduced V/sub GS/ (gate-to-source voltage) swing, it makes use of level-shift techniques to meet the constraints on the gate control signals. These static circuits permit the full output voltage swing of V/sub DDH/, while keeping the V/sub GS/ swing of the output devices within the safety limits, including during HV supply transients. Using a standard 2- mu m n-well CMOS technology, reliable, reproducible V/sub DS/ breakdown voltages as high as 120 V and 80 V have been obtained for HV-nMOS and HV-pMOS devices, respectively.< >
Design and Optimization of High-Voltage CMOS Devices Compatible wih a Standard 5V CMOS Technology
(1993)
High-voltage n- and p-MOSFETs fully compatible with a standard 5 V CMOS technology have been designed, optimized, and fabricated. No process changes are required. By modifying the logical equations generating one of the physical masks from the design masks, a p-type buffer region for the high-voltage p-MOS was easily implemented. This modification does not affect the low-voltage part of the circuits. These high-voltage devices have been used successfully as output drivers in semicustom arrays, and as building blocks for custom low- to high-voltage output interfaces. Aspects of reliability, device protection, and circuit design techniques are addressed.
The efficacy of psychological treatment to reduce pain has recently been shown in a number of studies. They are considered to enhance or even replace medical approaches in pain management, especially in chronic pain-states. The study reported here aimed to test two established (multimodal pain management, relaxation training) and one newly designed approach (visualization techniques) in comparison with a control group (medical treatment alone). The study was conducted with in-patients (N = 46; rheumatoid arthritis). Medical and pain data were gathered before and after treatment. Patients also filled out questionnaires in the beginning and at the end of the study assessing pain-experience, emotional states and capability to cope with pain. Patients participating in the multimodal pain management group and the visualization group profited from participation (especially in pain reduction) only if they gained substantially extents in the capability to cope with pain. Simply taking part in the groups and not reaching acceptable measures to cope with pain had no or negative effects. Both approaches were clearly above the control- and the relaxation-condition (relaxation participants were hardly better than the controls). The range of efficacy was broadest in the multimodal group (in addition to pain-reduction, substantial improvements in emotional states were obtained). However, visualization techniques, which were tested empirically for the first time here, can also be recommended as pain management therapy.
Berufliche Integration körperbehinderter Menschen : eine regionale Studie im Landkreis Regensburg
(1995)
We investigate the mechanical and microstructural properties of a diamond-like carbon coating (DLC) which is deposited by plasma enhanced chemical vapor deposition (PECVD) onto an alumina/aluminosilicate glass composite used for biomedical applications. Ball-on-ring tests yield a fracture strength that is essentially influenced by the surface topology/roughness. The surface topology of the coating is investigated by atomic force microscopy (AFM). Tribology tests and nanoindentation represent the wear resistance and hardness; these are properties that are mainly influenced by the microstructural properties of the DLC coating. This microstructure is investigated by transmission electron microscopy (TEM) and analyzed by parallel electron energy loss spectroscopy (PEELS). For the general applicability of the coated composite, the interfacial adhesion of the DLC coating on the comparably rough substrate (roughness amplitudes and wavelengths are in the micrometer range) is important. Therefore, we focus on TEM investigations that show the interface to be free of gaps and pores that we, together with a characteristic microstructure adjacent to the interface, relate to the excellent adhesion. The interlayer consists of a high density of SiC grains, part of them directly bound to the substrate, and part of them bound to other SiC grains. This interlayer is followed by an essentially different region of the coating as concerns the microstructure; this region consists of nanocrystalline diamond particles embedded in an amorphous carbon matrix. It is this heterogeneous microstructure to which we attribute (i) the good adhesion based upon the interface stabilizing SiC grains, and (ii) the high hardness and wear resistance based upon the diamond nanocrystals in the coating.
Alkoholabhängige Frauen nehmen im Bereich der Alkoholismusbehandlung in mehrfacher Hinsicht den Status einer Minderheit ein. Zum einen sind sie in Einrichtungen, in denen stationäre Behandlung angeboten wird, in Relation zu ihrem Anteil an der Gesamtzahl der alkoholabhängigen seltener anzutreffen als Manner; desweiteren sind sie in den Kliniken, in denen sie gemeinsam mit Männern behandelt werden, deutlich in der Minderheit und schließlich werden Themen, die sie betreffen im Rahmen der Behandlung seltener berücksichtigt.
Es werden mögliche Erklärungen dafür gesucht, weshalb Frauen Fachkliniken seltener in Anspruch nehmen als Männer. Au ßerdem werden Folgen der Minderheitssituation der Frauen für die Kliniken als Institutionen und die Interaktion zwischen Patientinnen und Patienten aufgezeigt.
Zensur im Internet?
(1996)
We briefly report on calculated addition spectra for electrons in a circular quantum dot with perpendicular magnetic field. We compare our current density functional theory calculations with recent experiments by Tarucha et al. [PRL 77, 3613 (1996)]. We find a very good qualitative agreement of the structures and find an additional effect caused by Hund's first rule in magnetic field, which gives rise to new substructures not discussed in the paper by Tarucha.
We investigate the mechanical and microstructural properties of a diamond-like carbon coating (DLC) which is deposited by plasma enhanced chemical vapor deposition (PECVD) onto an alumina/aluminosilicate glass composite used for biomedical applications. Ball-on-ring tests yield a fracture strength that is essentially influenced by the surface topology/roughness. The surface topology of the coating is investigated by atomic force microscopy (AFM). Tribology tests and nanoindentation represent the wear resistance and hardness; these are properties that are mainly influenced by the microstructural properties of the DLC coating. This microstructure is investigated by transmission electron microscopy (TEM) and analyzed by parallel electron energy loss spectroscopy (PEELS). For the general applicability of the coated composite, the interfacial adhesion of the DLC coating on the comparably rough substrate (roughness amplitudes and wavelengths are in the micrometer range) is important. Therefore, we focus on TEM investigations that show the interface to be free of gaps and pores that we, together with a characteristic microstructure adjacent to the interface, relate to the excellent adhesion. The interlayer consists of a high density of SiC grains, part of them directly bound to the substrate, and part of them bound to other SiC grains. This interlayer is followed by an essentially different region of the coating as concerns the microstructure; this region consists of nanocrystalline diamond particles embedded in an amorphous carbon matrix. It is this heterogeneous microstructure to which we attribute (i) the good adhesion based upon the interface stabilizing SiC grains, and (ii) the high hardness and wear resistance based upon the diamond nanocrystals in the coating.
The morphology and microstructure of an Al2O3 glass composite (trade name In-Ceram, Vita Zahnfabrik) were studied using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The composite was produced by infiltration of a lanthanum-based glass throughout a porous Al2O3 body. This alumina body was formed by three classes of particles differing in size and shape: faceted particles typically ≤4 μm in diameter, platelets of average diameter 8 μm, 1.5 μm thickness, and small spheres 0.4 μm in diameter. The outstanding strength properties of the composite (600 MPa, ball-on-ring test) are a result of the high wetting capability of the glass phase on the Al2O3 surface. In addition, plastic strain relaxation in the faceted particles by dislocation formation compensates partially for residual stresses and impedes crack formation at the glass/Al2O3 interface.
A methodology for the evaluation of the annual probability of occurrence of post-elastic seismic damage in realistic structures is presented. The seismic damage hazard analysis (SDHA) is carried out here by coupling conventional seismic hazard analysis (SHA) for the site and the structural response to earthquakes of different intensities. The structural performance is statistically investigated by conducting appropriate non-linear dynamic analyses for a limited set of real ground-motion records that might potentially pose a threat to the structure at the site. The merging of these two approaches permits calculation of the seismic hazard faced by the structure in direct damage terms. The methodology is presented in this paper with the aid of a simple illustrative case study where the annual probability of damage and, eventually, failure of a power house steel structure is computed. This methodology can find practical applications in seismic retrofit of nuclear power plant structures and in the evaluation of seismic damage hazards in new structure designs.
Zur diagnostischen Unterstützung bei der Befundung laryngealer Erkrankungen soll eine Farb- und Formanalyse der Stimmlippen durchgeführt werden. In diesem Beitrag wird ein Verfahren zur Trennung der spiegelnden und diffusen Reflexionsanteile in Farbbildern des Larynx vorgestellt. Die Farbe der diffusen Komponente entspricht dabei der beleuchtungsunabhängigen Objektfarbe, während deren Wichtungsfaktoren als Eingabe für Shape-from-Shading-Verfahren zur Oberflächenrekonstruktion dienen.
A method for solving networks containing generic analog components such as resistors, capacitors and inductors onan event driven time axis using digital VHDL is presented. The components are modeled as complex state machines communicating with their neighbors using INOUT type ports. The method takes advantage of simulation deltas to iterate without simulation-time consumption. A limited range of implicit equations can be solved this way.
Feedback-nach-Feedforward-Transformation zur Verhaltensmodellierung rückgekoppelter Verstärker
(1997)
A method to model high-gain feedback-loop analog amplifiers on an event driven timeaxis is presented. The demonstrator is coded in digital VHDL’93. In the event-driven scheme any node in the network must converge „on its own“ based on the information delivered from its neighbors, as no overall matrix is set up. For this reason signalloops with a loop gain larger than one are typically unstable. This communication presents a numerically stable generic model for high gain amplifiers with a userdefined feedback network. Non-ideal effects like offset or finite gain can be taken into account.
The mixed-signal event-driven (MixED) method developed to simulate small portions of analog circuitry within a digital environment is demonstrated in a mixed signal application. The MixED models using concurrent iteration to account for analog nodes were coded and run in standard VHDL’93. Networks containing linear components such as sources, resistors, capacitors, inductors and operational amplifiers are presented. The possibility to manipulate resistors during runtime is used to simulate switches.
Chronic pain has a variety of causes. Therefore patients with chronic pain should be treated in an interdisciplinary way. From a psychological point of view a cognitive-behavioral approach is preferred. This includes training for coping with pain as well as the added option of a comprehensive psychotherapy. This form of treatment seems to be indicated in most cases, but it is not suitable if the patient does not agree with the procedure, preferring instead a special kind of therapy which is not cognitive-behavioral. On the other hand a psychological treatment is not indicated if the therapist is not prepared to cooperate with other therapists in an interdisciplinary fashion.
Spritzbetone mit alkalifreier Erstarrungsbeschleunigung werden ohne alkalische Zusatzmittel (Spritz-Bindemittel mit begrenztem Alkaligehalt oder alkalifreiem Erstarrungsbeschleuniger) verarbeitet. Ein entscheidender Punkt fuer den Einsatz der alkalifreien Erstarrungsbeschleunigung ist das geunstige Auslaugverhalten, speziell hinsichtlich der Einbringung von Alkalien in Tunnelwaesser. Diese Spritzbetone zeigen bei Kontakt mit Wasser das gleiche Auslaugverhalten wie Normalbeton. Alkalihaltige Zusatzmittel fuehrten bisher bei unsachgemaesser Anwendung auch zu Veraetzungen der Haut und der Augen (bis zur Erblindung) sowie zu Reizungen der Schleimhaeute. Die arbeitshygienischen und oekologischen Nachteile klassischer alkalihaetiger Erstarrungsbeschleuniger wurden mit der neuen Technologie ueberwunden. Die Festigkeitsentwicklungen von Spritzbetonen mit alkalifreier Erstarrungsbeschleunigung weisen unterschiediche Charakteristika auf und weichen im Festigkeitsverlauf untereinander beziehungsweise gegenueber herkoemmlichen, mit alkalihaltigen Beschleunigern versehenen Spritzbetonen ab. Eine charakteristische Druckfestigkeitsentwicklung zeigen nur Spritzbetone unter Verwendung von Spritz-Bindemitteln fuer den Einsatz mit ofentrockenen Zuschlaegen beziehungsweise Spritz-Bindemittel auch mit naturfeuchten Zuschlaegen.Werden Zemente auf Basis von Portlandzementklinker mit alkalifreiem Erstarrungsbeschleuniger eingesetzt, so sind grosse Unterschiede im Festigkeitsverlauf, primaer abhaengig vom Erstarrungsbeschleunigergehalt und Wasserzement-Wert, sowohl im Trocken- als auch im Nassspritzverfahren feststellbar.
Double-layered quantum dots represent a novel realization of a multi-component plasma system. By modelling the system and applying classical concepts we investigate the oscillator strength of the acoustic plasma mode and its dependence on the system parameters. In view of recent experimental results, we discuss the observability of this collective excitation.
This paper firstly explains the basics of pathfollowing in nonlinear statics. It then discusses the four general approaches for solving the occurring sets of linear equations. As a result we introduce an Arnoldi (IOM)—Newton algorithm which has a wide range of application and is highly efficient, as it adapts its effort to the progress of the computation. Two examples are given to prove the good performance of the algorithm.
Soziales Kapital
(1997)
Der Begriff „soziales Kapital“ erfreut sich in den letzten Jahren zunehmender Verbreitung in sozialwissenschaftlichen Publikationen. In diesem Arbeitsbericht wird in Form eines Theorieüberblicks versucht, Aufschluß über die Notwendigkeit und Brauchbarkeit des Konzeptes „soziales Kapital“ zu gewinnen. Es wird untersucht, wie der Begriff bei verschiedenen Autoren definiert wird, welche inhaltlichen Aspekte und Dimensionen des Begriffs zu berücksichtigen sind, wie der Begriff bisher in der empirischen Forschung angewendet und operationalisiert wurde und welche Probleme sich daraus ergeben, welche theoretischen und empirischen Defizite weiterhin bestehen und wie eine wissenschaftstheoretische Beurteilung der bisherigen Forschungen aussieht. Zum Ursprung und der Verbreitung des Begriffs läßt sich feststellen, daß der Begriff innerhalb unterschiedlicher Arbeitsbereiche mehr oder weniger unabhängig voneinander entwickelt wurde, wobei sich mehrere Diskussionszusammenhänge und Verwendungsweisen identifizieren lassen. Es ist grundsätzlich zu unterscheiden zwischen dem Nutzen, den eine Person mit vielen und/oder aufwendig gepflegten sozialen Beziehungen selbst aus diesem „sozialen Kapital“ hat, dem Nutzen, den Personen, die geringen Aufwand zur Aufrechterhaltung von Beziehungen betreiben, haben, indem sie über Dritte („weak ties“) Zugang zu nützlichen Ressourcen erhalten können, und dem Nutzen, den das gesamte Kollektiv aus dem Vorhandensein von bestimmten (kleinen geschlossenen oder großen weitläufigen) Beziehungsnetzen und dem damit verbundenen „sozialen Kapital“ hat. Soziales Kapital wird in empirischen Studien sowohl als unabhängige als auch als abhängige Variable zur Erklärung der unterschiedlichsten Phänomene verwendet und es ist dabei keine einheitliche Operationalisierung feststellbar. Allgemein lassen sich bei der Verwendung des Begriffs des sozialen Kapitals zwei Analyseebenen unterscheiden: In verschiedenen individualistischen und netzwerktheoretischen Ansätzen wird soziales Kapital (analog zum Humankapital) als instrumentell einsetzbare, individuelle, aber nicht unabhängig von anderen Personen verfügbare, Ressource aufgefaßt. In der Debatte um politische Kultur dagegen wird das Gesamt-Sozialkapital oder Vertrauensniveau einer Gesellschaft als positiv bewertete Ressource der Gemeinschaft betrachtet, die zur Lösung von Kollektivgutproblemen beiträgt. Es stellt sich die Frage, ob es sinnvoll ist, alle diese Varianten mit dem Begriff des sozialen Kapitals zu bezeichnen.
We study the energy-level statistics for electrons in a lateral two-dimensional superlattice in dependence on the strength of the modulation potential at a given perpendicular magnetic field. The interminiband statistics at some selected point in the magnetic Brillouin zone shows a transition from degenerate Landau levels to universal spectral correlations while the corresponding classical dynamics displays a crossover from regular cyclotron orbits to chaotic motion. In terms of the nearest-neighbor spacing distribution, we observe the occurrence of level repulsion for all nonzero modulation amplitudes, which indicates a discontinuous transition to universal fluctuations for the smallest level spacings when the rotational invariance of the system is broken by a finite superlattice potential. In order to test the universality of the transition on larger scales, we propose a random matrix model with one transition parameter for comparison. Confirmed by two different types of potential shapes, we detect an explicit influence of the potential shape on the level spacing distributions, which hence cannot be described by the one-parameter model. Using the spectral rigidity, however, universal long-range fluctuations in the regime of negligible Landau-level mixing are found, in agreement with our random matrix model.
Magnetotransport in lateral superlattices covers a variety of apparently different physics dependent on the amplitude of the modulation potential relative to the Fermi energy ranging from the weakly modulated 2DEG to the antidot lattice. Here we investigate the transition between weak modulation and antidots within the quantum-mechanical theory by studying (i) the single-particle spectrum with respect to quantum signatures of classical chaos and (ii) the change of characteristic features in the magnetoresistance starting from the Kubo formula.
Each particular implementation of the beam propagation method (BPM) requires a special procedure allowing for radiation to leave the computational window. We propose a new approach to constructing the finite difference schemes of the BPM at the boundary of the computational window. These schemes are independent of the computed fields and allow for a similar treatment of both interior and boundary points. The new approach can be further improved by correcting the field values at the boundary points according to Hadley's method. The algorithm is easy to implement for both two- and three-dimensional structures. The new method considerably reduces computation times because the propagation matrices remain constant in longitudinally invariant sections, thus avoiding repeated LU-decompositions. The basic idea-establishing the finite difference scheme such that locally exact, approximate, or plausible solutions are recovered-may be of interest for other efforts to solve partial differential equations by the finite difference method.
Effective coupling between two remote optical waveguides without branching sections can be achieved in a three-guide system with multimode central waveguide. We investigate the nonlinear power switching of c.w. laser radiation by such radiatively coupled waveguides. It is shown that effective all-optical switches with spatially well separated input/output channels can be realized although the influence of multimode interference on the switching characteristics becomes more pronounced for increasing thickness of the central guide. Different coupling regimes are specified, and the changes in switching characteristics during the transformation from one regime to another is studied. Numerical calculations for the critical power are compared with an approximate analytical expression. It is also shown that, at a moderate input power, a small number of modes determines the switching behavior.
We investigate a system of two waveguides with leaky modes sharing a common substrate (radiatively coupled waveguides). The main advantage of such a system is the possibility of remote coupling. A perturbation theory is developed for both TE and TM polarization. Numerical calculations of dispersion curves and of the coupling length allow us to determine the limitations of the perturbation theory. We study the influence of multimode interference on the process of beating by considering the propagation of a given initial field. Finally, we propose a new design for an effective, integrated optical TE-TM polarization splitter.
In a three-guide coupler with multimode central waveguide, more than two modes of the entire structure participate in the coupling between the outer waveguides. Using a three-mode approximation we found simple conditions for complete power transfer between the outer waveguides: the device length has to match certain multiples of the con- ventionally defined coupling length. The specific form of the relevant modes allows us to design a magneto-optic isolator or circulator with significantly reduced device length (as compared to the conventional nonreciprocal coupler). The performance of the proposed devices is simulated by propagating-mode calculations. Estimates for admissible fabrication tolerances for the layer thicknesses are presented.
The anisotropy ΔS of the thermopower in thin films of the high-Tc superconductor Bi2Sr2CaCu2O8 is investigated using off–c-axis epitaxial film growth and the off-diagonal Seebeck effect. The measurements represent a new method for the investigation of anisotropic transport properties in solids, taking advantage of the availability of oriented grown crystalline thin films instead of using bulk crystals. First results for the temperature dependence ΔS(T) in Bi2Sr2CaCu2O8 thin films are presented and described within a two-band model. Subjecting the films to heat treatments in different gases at relatively low temperatures, ΔS could reversibly be changed in a wide range.
Magnetoresistance measurements and theoretical calculations for two-dimensional electron systems under a perpendicular magnetic field are presented which illuminate transport effects due to a periodic electrostatic potential modulation. We focus on features arising from the resolution of the magnetic miniband structure which are beyond the perturbative regime governed by the dispersion of Landau bands. Our non-perturbative quantum-mechanical calculations reveal that the dispersion of individual minibands is responsible for the complicated behaviour of the magnetoresistance in the regime of intermediate modulation strength. In particular, the interplay between miniband and scattering contributions to the conductivity leads to an almost structureless magnetoresistance in this regime followed by the formation of antidot peaks due to the miniband conductivity.
Ground-state calculations based on current spin density-functional theory for circular parabolic quantum dots are presented which reveal interesting spin effects in dependence on an external magnetic field: Hund's first rule (well-known from atomic physics for zero magnetic field) is related to the level occupancy near the Fermi energy and determines the spin configuration of the ground state in finite magnetic field. Consequently, the addition spectrum of the quantum dot exhibits a specific non-monotonous dependence on magnetic field, which is visible in recent quantum transport experiments.
We report on ground-state calculations based on current-spin density-functional theory for circular parabolic quantum dots. Hund's first rule, well-known from atomic physics, applies not only at zero magnetic field; analogous rules, related to the level occupancy near the Fermi energy, determine the spin configuration of the ground state in finite magnetic field. Consequently, the addition spectrum of the quantum dot exhibits a specific non-monotonous dependence on magnetic field. We discuss our results with focus on recent experiments which may already contain indications of this new feature.
We present current-spin density-functional calculations for circular parabolic quantum dots in zero magnetic field. We find the possibility for broken time-reversal symmetry via exchange correlation with spontaneously induced orbital currents. For certain electron numbers, this results in new current textures which give rise to a finite magnetization even for ground states with vanishing total angular momentum.
Three-guide couplers with multimode central waveguides allow for remote coupling between optical channels. A simple three mode approximation turns out to be sufficient for the description of the main features of the power transfer behavior. The specific form of the relevant modes suggests the design of integrated optical isolators and circulators based on magnetic garnet materials. These novel devices are superior to conventional nonreciprocal couplers with respect to the total length and admissible fabrication tolerances. We characterize the isolation performance and the transmission loss for the proposed devices by propagating mode simulations and estimate the influence of geometry parameter deviations.
Quantitative Farbmessungen sollen die Diagnostik laryngealer Erkrankungen unterstützen. Dabei wird der Farbeindruck nicht nur durch die Reflexionseigenschaften des Gewebes sondern auch durch die Farbe der verwendeten Lichtquelle beeinflußt. Der hier vorgestellte Farbkonstanz-Algorithmus basiert auf dem dichromatischen Reflexionsmodell und liefert eine pixelweise Trennung des Farbbildes in seine beiden Faxbanteile. Die Körperfarbe entspricht dabei der gewebespezifischen Reflexion, die Oberfächenfarbe der Strahlung der Lichtquelle.
Laryngoscopic images of the vocal tract are used for diagnostic purposes. Quantitative mea-surements like changes of the glottis size or the surface of the vocal cords during an image sequence can be helpful to describe the healing process or to compare the findings of diffe-rent patients. Typically the endoscopic images are circulary symmetric distorted (barrel di-stortion). Therefore measurements of geometric dimensions depend on the object´s position in the image. In this paper an algorithm is presented which allows the computation of the translational invariant "real" object size by correcting the image distortion without using additional calibration of the optical environment.
Nutzung eines Farbkonstanz-Algorithmus zur Entfernung von Glanzlichtern in laryngoskopischen Bildern
(1998)
1 Einführung
Funktionelle und organische Störungen im Larynx beeinträchtigen die Ausdrucksfähigkeit des Menschen. Zur Diagnostik und Verlaufkontrolle werden die Stimmlippen im Larynx mit Hilfe der Video-Laryngoskopie aufgenommen. Zur optimalen Farbmessung wird dazu an das Lupenendoskop eine 3-Chip-CCD-Kamera angeschlossen, die eine unabhängige Aufnahme der drei Farbkanäle erlaubt. Die bisherige subjektive Befundung ist von der Erfahrung des Untersuchers abhängig und läßt nur eine grobe Klassifikation der Krankheitsbilder zu. Zur Objektivierung werden daher quantitative Parameter für Farbe, Textur und Schwingung entwickelt. Neben dem Einfluß der wechselnden Lichtquellenfarbe auf den Farbeindruck ist die Sekretauflage auf den Stimmlippen ein Problem bei der Farb-und Texturanalyse. Sie kann zu ausgedehnten Glanzlichtern führen und so weite Bereiche der Stimmlippen für die Farb-und Texturanalyse unbrauchbar machen. Dieser Beitrag stellt einen Farbkonstanz-Algorithmus vor, der unabhängig von der Lichtquelle quantitative Farbwerte des Gewebes liefert und die Glanzlichtdetektion und -elimination ermöglicht.
2 Methodik
Ziel des Farbkonstanz-Algorithmus ist die Trennung von Lichtquellen-und Gewebefarbe. Unter Verwendung des dichromatischen Reflexionsmodells [1] kann die Oberflächenreflexion mit der Farbe der Lichtquelle und die Körperreflexion mit der Gewebefarbe identifiziert werden. Der Farbeindruck entsteht aus der Linearkombination beider Farbkomponenten. Ihre Gewichtung ist von der Aufnahmegeometrie abhängig, insbesondere vom Winkel zwischen Oberflächennormalen und dem Positionsvektor der Lichtquelle. In einem zweistufigen Verfahren wird zunächst die Lichtquellenfarbe geschätzt, dann die Gewebefarbe ermittelt. Hieraus können beide Farbanteile durch die Berechnung der Gewichtsfaktoren pixelweise getrennt werden.
Video Documentation of endoscopic findings simplifies diagnostic counseling of the patient and aids pre-operative discussion among the medical team. Judgment of such images is still subjective and can not give a quantitative evaluation of the disease process regarding diagnosis or response to treatment. Modern treatment of early laryngeal cancer with laserablation requires intensive follow up and frequent direct laryngoscopy under general anesthesia with blind biopsies to detect any tumor residual or recurrence. Inflammatory conditions of the larynx are frequently confused with other causes of dysphonia. Mapping anddigital analysis of the documented image will suggest the tumor site and avoids undue blind biopsies under anesthesia. However, varying illumination results in different colors reflected from the same object. To achieve quantitative analysis, color constancy has to be assured. Inthis paper, the environment is presented which allow the objective judgment of larngoscopies.
The mixed-signal event-driven (MixED) simulationalgorithm using standard VHDL is capable of modelinga number of analog and mixed-signal problems in digital circuits, e.g. RCL networks representing pads or wires, charge pumps, dynamic logic, voltage-controlledoscillators, phase-locked loops, etc. Important featuresare single-kernel simulation as well as rapid A/D andD/A interfacing.
This paper demonstrates the simulation of a phase-locked loop (PLL), which is one of the most interesting applications of the MixED method. Many digital designs contain a PLL as only mixed-signal building block. The MixED method allows to simulate such designs with standard VHDL.