30 research outputs found

    RSFQ Circuitry Using Intrinsic π-Phase Shifts

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    The latching of temporary data is essential in the rapid single flux quantum (RSFQ) electronics family. Its pulse-driven nature requires two or more stable states in almost all cells. Storage loops must be designed to have exactly two stable states for binary data representation. In conventional RSFQ such loops are constructed to have two stable states, e.g. by using asymmetric bias currents. This bistability naturally occurs when phase-shifting elements are included in the circuitry, such as pi-Josephson junctions or a pi-phase shift associated with an unconventional (d-wave) order parameter symmetry. Both approaches can be treated completely analogously, giving the same results. We have demonstrated for the first time the correct operation of a logic circuit, a toggle-flip-flop, using rings with an intrinsic pi-phase shift (pi-rings) based on hybrid high-Tc to low-Tc Josephson junctions. Because of their natural bistability these pi-rings improve the device symmetry, enhance operation margins and alleviate the need for bias current lines.\ud \u

    Integration of an ultraviolet direct write laser and its red differential confocal probe

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    The maskless photolithography method direct laser writing (DLW) can achieve sub-100-nm writing resolution if the photoresist is kept well on the plane of best focus of the optical system. Deviation from this plane leads to larger than intended or loss of developed areas. Here we present an approach to account for this problem through a Bessel-Gauss beam for the exposure

    Measurement precision of a planar nanopositioning machine with a range of motion of Ø100 mm

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    This work deals with various investigations into the accuracy of a newly developed planar nanopositioning machine. This machine, called Nanofabrication Machine 100 (NFM-100), has a positioning range of 100 mm in diameter. To determine the precision, various movement scenarios are performed with the machine table, and the trajectory deviation from the set trajectory is determined. In particular, the focus is on high velocities of up to 20 mm/s. Even at high speeds in the range of several millimetres per second, this machine can impress with its performance and only has a deviation in the nanometre range

    Measurement uncertainty analysis on a five-axis nano coordinate measuring machine NMM-5D following a vectorial approach

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    Dieser Beitrag zeigt ein Konzept für eine fünfachsige Nano-Koordinatenmessmaschine zur Messung auf stark gekrümmten asphärischen und frei geformten optischen Oberflächen in einem Messvolumen von 25mm × 25mm × 5mm mit einem maximal möglichen Neigungswinkel von bis zu 60° zur Hochachse und einer maximalen Rotation von 360° um die Hochachse. Dabei wird die Probe translatorisch bewegt und der Sensor in seiner Orientierung verändert. Unter Einhaltung des Abbe-Komparatorprinzips für alle Messachsen wird die Bewegungsabweichung des Sensors bei der Rotation durch ein in-situ-Referenzmesssystem erfasst. Dieses besteht aus drei kartesisch angeordneten Fabry-Pérot-Interferometern mit dem Ursprung im Antastpunktes des Sensors, die den Abstand zu einer hemisphärischen Referenzfläche messen. Die Messunsicherheitsbetrachtung des Gesamtsystems erfolgt nach dem guide to the expression of uncertainty in measurement in einem vektoriellen Ansatz und liefert unter konservativen Annahmen eine Unsicherheit des Antastpunktes von maximal 72 nm (k=1).In this paper a novel concept of an five axes nano coordinate measuring machine for the measurement on strongly curved aspheric and freeform optics is shown. Thereby the sample is moved translational in a measuring volume of 25mm×25mm×5mm and the sensor can be tilted up to an angle of 60° and it can be rotated up 360° around the z-axis. By strictly following the abbe comparator principle, the motion error that occurs during the sensor rotation is measured by an in-situ reference measuring system. It consists of three Fabry-Pérot-Interferometers whose measuring directions span a cartesian coordinate system with the origin in the sensors probing point. Those interferometers measure the distance to concentric arranged reference hemisphere. The measurement uncertainty is derived according to the Guide to the expression of uncertainty in measurement. A conservative estimation shows a maximum uncertainty of the probing point of 72 nm (k=1)

    Wirbellose Neozoen im Bodensee : neu eingeschleppte invasive Benthos-Arten ; Monitoringprogramm Bodenseeufer 2004 / LfU, Landesanstalt für Umweltschutz Baden-Württemberg. Bearb. Peter Rey ...

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    Der Große Höckerflohkrebs Dikerogammarus villosus und die Körbchenmuschel Corbicula fluminea zeigen in den Bundeswasserstraßen Rhein, Main, Donau, Neckar und Mosel seit Mitte der 1990er Jahre invasorische Ausbreitungstendenzen. Beide Arten wurden nun auch im Bodensee nachgewiesen. Zwischen Juni und November 2004 wurde ihre Ausbreitung im Rahmen des vorliegenden Untersuchungsprogramms dokumentiert. Mit Hilfe eines dichten Probestellennetzes konnten die aktuellen Verbreitungsgrenzen der beiden Arten unterschiedlich genau abgegrenzt werden. Durch flächenbezogene Proben und Proben aus verschiedenen Wassertiefen wurden Informationen über ihre relative Besiedlungsdichte und Biomasse gewonnen. Die Proben von Uferabschnitten außerhalb der aktuellen Verbreitung der beiden Arten lieferten Referenzdaten zur Zusammensetzung der bisherigen Benthosbiozönose. Die Überprüfung (Screening) bisher noch nicht bearbeiteter Proben von Dauerbeobachtungsstellen des Limnologischen Instituts der Universität Konstanz erbrachte, dass Dikerogammarus villosus bereits im Oktober 2002 bei Immenstaad am nördlichen Bodenseeufer mit wenigen Exemplaren vorkam. Auf der Westseite des Überlingersees (Wallhausen) wurde Dikerogammarus in Uferproben seit August 2003 nachgewiesen; hier wurde er jedoch bereits seit Februar 2003 lokal beobachtet. Dikerogammarus breitete sich seither über den gesamten nordwestlichen Teil des Bodensees aus. Seine westliche Ausbreitungsgrenze lag im November 2004 im Konstanzer Trichter oberhalb des Seerheins. Seit Februar 2004 zeigte diese Krebspopulation eine Arealvergrösserung von rund 4 km Uferlänge. Seine nordöstliche Verbreitungsgrenze liegt bei Langenargen, möglicherweise handelt es sich hier um eine zweite Inizialpopulation. Dikerogammarus zeigte innerhalb seiner Verbreitungsgrenzen eine auffällige Habitatkonkurrenz gegenüber anderen Benthosorganismen, vor allem gegenüber der bisher im See dominierenden Flohkrebsart Gammarus roeseli. Die durchschnittlichen Besiedlungsdichten von Dikerogammarus liegen zwar bisher unter denen der zuvor an gleicher Stelle siedelnden G. roeseli; auf geeignetem Substrat zeigte jedoch auch Dikerogammarus Massenvorkommen mit über 2000 Individuen/m2. Corbicula fluminea besiedelte im September 2004 am vorarlbergischen Rohrspitz einen Flachwasserbereich von rund 5 km Länge. Die Art kommt im ganzen Bodensee bisher nur in diesem Bereich vor und zeigt dort ohne ihre mindestens ebenso häufigen Individuen 2mm zu berücksichtigen, maximale Besiedlungsdichten von rund 600 Individuen/m2. Eine im Rahmen des vorliegenden Programms konzipierte Datenbankstruktur dient künftig dazu, recherchierte, aktuelle und gesammelte Informationen zur Neozoenausbreitung - auch über regionale Grenzen hinweg - zentral zusammenzustellen und mit Hilfe eines geografischen Informationssystems darzustellen. Mit dem Untersuchungsprogramm sollte die Grundlage für Langzeitbeobachtungen invasorischer Neozoen im Bodensee und seinem Einzugsgebiet bereitstellt werden. Neben den Benthosuntersuchungen am Bodenseeufer wurde auch begonnen, weitere Informationen über Bodensee-Neozoen zusammen zu stellen. Ein Informationsaustausch erfolgt seither mit allen namhaften Forschungsinstitutionen und Gewässerschutzfachstellen am Bodensee und in seinem Einzugsgebiet

    An electrothermally actuated Membrane as oscillating Pinhole for the highfrequent Modulation of Light

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    Differential Confocal Microscopy (DCM) can provide nanometer depth sensitivity for optical profilometry. We investigate a new approach for the creation of a differential depth signal through an oscillating pinhole, thereby reducing overall size, yet enhancing speed of the detection

    Tip- and laser-based 3D nanofabrication in extended macroscopic working areas

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    The field of optical lithography is subject to intense research and has gained enormous improvement. However, the effort necessary for creating structures at the size of 20 nm and below is considerable using conventional technologies. This effort and the resulting financial requirements can only be tackled by few global companies and thus a paradigm change for the semiconductor industry is conceivable: custom design and solutions for specific applications will dominate future development (Fritze in: Panning EM, Liddle JA (eds) Novel patterning technologies. International society for optics and photonics. SPIE, Bellingham, 2021. https://doi.org/10.1117/12.2593229). For this reason, new aspects arise for future lithography, which is why enormous effort has been directed to the development of alternative fabrication technologies. Yet, the technologies emerging from this process, which are promising for coping with the current resolution and accuracy challenges, are only demonstrated as a proof-of-concept on a lab scale of several square micrometers. Such scale is not adequate for the requirements of modern lithography; therefore, there is the need for new and alternative cross-scale solutions to further advance the possibilities of unconventional nanotechnologies. Similar challenges arise because of the technical progress in various other fields, realizing new and unique functionalities based on nanoscale effects, e.g., in nanophotonics, quantum computing, energy harvesting, and life sciences. Experimental platforms for basic research in the field of scale-spanning nanomeasuring and nanofabrication are necessary for these tasks, which are available at the Technische Universität Ilmenau in the form of nanopositioning and nanomeasuring (NPM) machines. With this equipment, the limits of technical structurability are explored for high-performance tip-based and laser-based processes for enabling real 3D nanofabrication with the highest precision in an adequate working range of several thousand cubic millimeters

    Importance of artificial high flows in maintaining the ecological integrity of a regulated river

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    Artificial high flows attempt to simulate natural flood pulses in flow-regulated rivers with the intent to improve their ecological integrity. The long-term use of such high flow events have shown beneficial ecological effects on various rivers globally. However, such responses are often non-linear and characterized by underlying feedback mechanisms among ecosystem components. The question arises as to what happens when such high flow releases are disrupted or even discontinued. Here, we used the long-term (22 years) monitoring dataset from the river Spöl to examine whether discontinuation (2016–2021) of the flood program (annual artificial high flows from 2000 to 2016) resulted in the ecological degradation of the river. We used monitoring data of physico-chemistry, periphyton, benthic organic matter, macroinvertebrates and fish (brown trout, Salmo trutta fario L.) in the analysis. The flood program had no long-term effect on water physico-chemistry with most parameters showing typical variations associated with season and inter-annual weather patterns. The floods were effective at mobilizing bed sediments that reduced periphyton biomass and benthic organic matter following each flood. Increases in periphyton biomass and benthic organic matter occurred between floods, but both parameters showed no significant increase with discontinuation of the flood program. Floods reduced macroinvertebrate densities, but with density increases occurring between floods. The pulsed disturbances, and the progressive change in the habitat template, resulted in shifts in community assembly by reducing densities of Gammarus fossarum, a dominant crustacean, which allowed other taxa to colonize the system. Macroinvertebrate densities remained low after discontinuation of the floods, although G. fossarum densities have increased substantially while other taxa, especially some stoneflies, remained low in abundance. Notably, community assembly returned to a pre-flood composition with discontinuation of the floods. The abundance of brown trout increased substantially during the flood program but returned to low pre-flood numbers with discontinuation of the floods. We conclude that the flood program was beneficial to the ecology of the river Spöl and discontinuation of the floods resulted in degradation of the system after a relatively short lag period. However, the system showed high resilience to an earlier perturbation, a sediment spill in 2013, suggesting a rapid positive response by biota with resumption of the flood program.ISSN:0048-9697ISSN:1879-102
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