Ultraviolet photodetectors and readout based on a-IGZO semiconductor technology

In this work, real-time ultraviolet photodetectors are realized through metal–semiconductor–metal (MSM) structures. Amorphous indium gallium zinc oxide (a-IGZO) is used as semiconductor material and gold as metal electrodes. The readout of an individual sensor is implemented by a transimpedance amplifier (TIA) consisting of an all-enhancement a-IGZO thin-film transistor (TFT) operational amplifier and a switched capacitor (SC) as feedback resistance. The photosensor and the transimpedance amplifier are both manufactured on glass substrates. The measured photosensor possesses a high responsivity R , a low response time t _{R E S} , and a good noise equivalent power value NEP .     

On the adjoint-consistent formulation of interface conditions in goal-oriented error estimation and adaptivity for fluid–structure interaction

The numerical solution of fluid–structure-interaction problems poses a paradox in that most of the computational resources are consumed by the subsystem of least practical interest, viz., the fluid. Goal-oriented adaptive discretization methods provide a paradigm to bypass this paradox. Based on the solution of a dual problem, the contribution of local residuals to the error in a specific goal functional is estimated, and only the regions that yield a dominant contribution are refined. In the present work, we address a fundamental complication in the application of goal-oriented adaptivity to fluid–structure-interaction problems, namely, that the treatment of the interface conditions has nontrivial consequences for the properties of the dual problem. In the context of a linearized model problem, we consider two equivalent discretizations differing only on the formulation of the interface coupling terms. By means of an adjoint consistency analysis, we show that only one of these discretizations is adjoint consistent. Numerical experiments convey that the two discretizations behave very differently for the dual problem, and that the adjoint-consistent discretization yields more reliable error estimates. Based on the adjoint-consistent discretization, we finally present some h- and hp-adaptive results, confirming that tremendous savings in computational cost can be realized through the use of goal-oriented refinement strategies. The numerical experiments illustrate that the goal-oriented approach effectively equilibrates the error contributions of the fluid and structure subsystems, which is imperative for efficiently resolving the coupled fluid–structure-interaction problem, and which cannot be accomplished by uniform or residual-based refinement strategies.     

Method development for epoxy resin analysis

Epoxy resin based negative photo resists are showing interesting properties which are useful for a series of applications in electronic industries (Mark et al. in Encyclopedia of polymer science and engineering, Wiley, New York, 1986; Potter in Epoxide resins, Springer, New York, 1970; May and Tanka in Epoxy resin chemistry and technology, Marcel Dekker, New York, 1973; Bauer in Epoxy resin chemistry, vol 114, American Chemical Society, Washington, 1979; Hood in RAPRA Rev Rep 38:4, 1990). Especially in micro system technologies they promise a high potential. To adjust the properties for the particular application modification of the chemical composition and crosslinker system must be performed. An actual problem is the constancy in behaviour during the LIGA-process of the resist mixture. In this work analytical techniques are used to get a detailed insight into the chemical composition of a commercial available epoxy novolac resin. Methods like size exclusion chromatography (SEC), matrix assisted laser desorption-time of flight (MALDI-ToF) and fourier transform infrared spectroscopy (FTIR) offer information about the molecular weight and functionality. The results reveal a distribution in molecular weight and functionality. Due this the resin was chemically modified. After processing a dependency of molecular weight and therefore the amount of epoxy groups existent was obtained.     

Estimation of Detection Thresholds for Redirected Walking Techniques

In immersive virtual environments (IVEs), users can control their virtual viewpoint by moving their tracked head and walking through the real world. Usually, movements in the real world are mapped one-to-one to virtual camera motions. With redirection techniques, the virtual camera is manipulated by applying gains to user motion so that the virtual world moves differently than the real world. Thus, users can walk through large-scale IVEs while physically remaining in a reasonably small workspace. In psychophysical experiments with a two-alternative forced-choice task, we have quantified how much humans can unknowingly be redirected on physical paths that are different from the visually perceived paths. We tested 12 subjects in three different experiments: (E1) discrimination between virtual and physical rotations, (E2) discrimination between virtual and physical straightforward movements, and (E3) discrimination of path curvature. In experiment E1, subjects performed rotations with different gains, and then had to choose whether the visually perceived rotation was smaller or greater than the physical rotation. In experiment E2, subjects chose whether the physical walk was shorter or longer than the visually perceived scaled travel distance. In experiment E3, subjects estimate the path curvature when walking a curved path in the real world while the visual display shows a straight path in the virtual world. Our results show that users can be turned physically about 49 percent more or 20 percent less than the perceived virtual rotation, distances can be downscaled by 14 percent and upscaled by 26 percent, and users can be redirected on a circular arc with a radius greater than 22 m while they believe that they are walking straight.     

Low retaining force optical viewport seal

We report on the experimental realization of an ultrahigh vacuum (UHV) indium sealing between a conflat knife edge and an optical window. The sealing requires a very low clamping force and thus allows for the use of very thin and fragile windows.     

From concepts to consistent object specifications: Translation of a domain-oriented feature framework into practice

A steady increase in consumer demands,and severe constraints from both a somewhat damaged environment and newly installed government policies,require today‘s product design and development to be faster and more efficient than ever before,yet utilizing even fewer resources.New holistic approaches,such at total product life cycle modeling which embraces all aspercts of a product‘s life cycle,are current attempts to solve these problems,Within the field of product design and modeling,feature technology has proved to be one very promising solution component.Owing to the tremendous increase in information technology,to transfer from low level data processing towards knowledge modeling and information processing is about to bring a change in almost every computerized application.From this viewpoint,current problems of both feature frameworks and feature systems are analyzed in respect to static and dynamic consistency breakdowns.The analysis ranges from early stager of designing(feature)concepts to final system implementation and application.For the first tie,an integrated view is given on approaches,solutions and practical experience,with feature concepts and structures,providing both a feature framework and its implementation with sufficient system architecture and computational power to master a fair number of known consistency breakdowns,while providing for robust contexts for feature semantics and integrated models.Within today;s heavy use of information technology these are pre-requisites if the full potential of feature technology is to be successfully translated into practice.     

Beziehungen zwischen Struktur und Geschmack bei Aminos?uren mit cyclischen Seitenketten

Zusammenfassung 1-Aminocycloalkan-l-carbonsäuren mit Ringgrößen von 4–11 (ohne 10) wurden synthetisiert und auf ihre Geschmackseigenschaften untersucht. Süßer Geschmack tritt vom 4-Ring bis zum 8-Ring auf, beim 6-Ring ist der Schwellenwert minimal (c _Ssü=1–3 mmol/l). Bitter sind die Verbindungen vom 5-Ring bis zum 9-Ring, das Minimum des Schwellenwertes liegt beim 8-Ring (c _sbi=2–5 mmol/l). Die größeren Ringe sind bis zu Konzentrationen von 20 mmol/l ohne Geschmack. Beim 6-Ring löscht eine 2-Methylgruppe jeden Geschmackseindruck, während die 3- und 4-Methylverbindungen süß und bitter sind. Die 4-Äthylverbindung ist bitter aber nicht süß, die 4-tert.-Butylverbindung ist ohne Geschmack. 1-Aminonorbornan-1-carbonsäure ist süß (c _Ssü 50 mmol/l) und bitter (c _sbi=5–7mmo1/1), wobei der Schwellenwert für bitter fast eine Zehnerpotenz kleiner ist. tert.-Leucin ist ohne Geschmack. Die Ergebnisse werden im Zusammenhang mit früheren Untersuchungen an offenkettigen Aminosäuren diskutiert und in Modelle über sterische Voraussetzungen für Geschmack eingeordnet.

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Relationsships between structure and taste in amino acids with cyclic side chains

Summary 1-Aminocycloalkane-1-carboxylic acids with ring sizes of 4–11 (excluding 10) were synthesized and tested for their taste properties. The compounds with 4- to 8-membered rings are sweet, with threshold values going through a minimum for the 6-membered ring (c _tsw = l-3 mM/l). The compounds with 5- to 9-membered rings are bitter. Here the threshold value reaches a minimum for the 8-membered ring (c _tbi=2–5 mM/l). The larger rings are without taste up to concentrations of 20 mmol/l. With the 6-membered ring a 2-methyl group abolishes any taste impression, whereas the 3- and 4-methyl compounds are sweet and bitter. The 4-ethyl compound is bitter but not sweet, the 4-tert.-butyl compound has no taste. 1-Aminonorbornane-l-carboxylic acid is sweet (c _tsw 50mM/l) and bitter (c _tbi= 5–7 mM/l), withc _tbi being significantly smaller thanc _tsw. tert-Leucine is without taste. The results are discussed in relation to previous investigations into steric prerequisites for taste in the amino acid series.