681 research outputs found
Heat transfer coefficient saturation in superconducting Nb tunnel junctions contacted to a NbTiN circuit and an Au energy relaxation layer
In this paper we present the experimental realization of a Nb tunnel junction
connected to a high-gap superconducting NbTiN embedding circuit. We investigate
relaxation of nonequilibrium quasiparticles in a small volume Au layer between
the Nb tunnel junction and the NbTiN circuit. We find a saturation in the
effective heat-transfer coefficient consistent with a simple theoretical model.
This saturation is determined by the thickness of the Au layer. Our findings
are important for the design of the ideal Au energy relaxation layer for
practical SIS heterodyne mixers and we suggest two geometries, one, using a
circular Au layer and, two, using a half-circular Au layer. Our work is
concluded with an outlook of our future experiments.Comment: Applied Superconductivity Conference 201
Anatomical information science
The Foundational Model of Anatomy (FMA) is a map of the human body. Like maps of other sorts – including the map-like representations we find in familiar anatomical atlases – it is a representation of a certain portion of spatial reality as it exists at a certain (idealized) instant of time. But unlike other maps, the FMA comes in the form of a sophisticated ontology of its objectdomain, comprising some 1.5 million statements of anatomical relations among some 70,000 anatomical kinds. It is further distinguished from other maps in that it represents not some specific portion of spatial reality (say: Leeds in 1996), but rather the generalized or idealized spatial reality associated with a generalized or idealized human being at some generalized or idealized instant of time. It will be our concern in what follows to outline the approach to ontology that is represented by the FMA and to argue that it can serve as the basis for a new type of anatomical information science. We also draw some implications for our understanding of spatial reasoning and spatial ontologies in general
Protein-Interaction-Networks: More than mere modules
Cellular function is widely believed to be organized in a modular fashion. On
all scales and at all levels of complexity, relatively independent sub-units
perform relatively independent sub-tasks of biological function. This
functional modularity must be reflected in the topology of molecular networks.
But how a functional module should be represented in an interaction network is
an open question. In protein-interaction networks (PIN), one can identify a
protein-complex as a module on a small scale, i.e. modules are understood as
densely linked, resp. interacting, groups of proteins, that are only sparsely
interacting with the rest of the network.
In this contribution, we show that extrapolating this concept of cohesively
linked clusters of proteins as modules to the scale of the entire PIN
inevitable misses important and functionally relevant structure inherent in the
network. As an alternative, we introduce a novel way of decomposing a network
into functional roles and show that this represents network structure and
function more efficiently. This finding should have a profound impact on all
module assisted methods of protein function prediction and should shed new
light on how functional modules can be represented in molecular interaction
networks in general
Magnetic properties of single nanomagnets: EMCD on FePt nanoparticles
Energy-loss magnetic chiral dichroism (EMCD) allows for the quantification of
magnetic properties of materials at the nanometer scale. It is shown that with
the support of simulations that help to identify the optimal conditions for a
successful experiment and upon implementing measurement routines that
effectively reduce the noise floor, EMCD measurements can be pushed towards
quantitative magnetic measurements even on individual nanoparticles. With this
approach, the ratio of orbital to spin magnetic moments for the Fe atoms in a
single L ordered FePt nanoparticle is determined to be . This finding is in good quantitative agreement with the results of
XMCD ensemble measurements.Comment: 35 pages, 10 figure
Eine Web-Applikation zur Optimierung der KrĂĽmmung von Line Source Arrays
DFG, 393106680, Optimale Schallfelderzeugung fĂĽr Beschallungsaufgaben im Zeit- und Frequenzbereic
Mixed Analytical-Numerical Filter Design for Optimized Electronic Control of Line Source Arrays
Line source arrays (LSAs) are used for large-scale sound reinforcement that synthesizes homogeneous sound fields over the full audio bandwidth. The deployed loudspeaker cabinets are rigged with different tilt angles and are electronically controlled to provide the intended coverage of the audience zones and to avoid radiation toward the ceiling, reflective walls, or residential areas. In this article, a mixed analytical-numerical approach, referred to as line source array venue slice drive optimization (LAVDO), is introduced for optimizing the individual loudspeakers’ driving functions. This method is compared to numerical optimization schemes, including least-squares and multi-objective goal attainment approaches. For two standard LSAs in straight and in curved configuration, these temporal frequency domain optimizations are performed for a typical concert venue. It is shown that LAVDO overcomes the nonsmooth frequency responses resulting from numerical frequency domain approaches. LAVDO provides smooth amplitude and phase responses of the loudspeakers’ driving functions that are essential for practical finite impulse response filter design and implementation
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