The brightness distribution of IRC +10216 at 11 microns

The brightness distribution of IRC +10216 at a wavelength of 11 microns was measured in detail using a spatial interferometer. This brightness distribution appears to have azimuthal symmetry; an upper limit of 1.1 may be set to the ellipticity at 11 microns if the object has a major axis oriented either along or perpendicular to the major axis of the optical image. The radial distribution shows both compact and extended emission. The extended component, which is due to thermal emission from circumstellar dust, contributes 91% of the total flux and has a 1/e diameter of 0.90 minutes. The tapered shape of this component is consistent with a l/r squared dust density dependence. The compact component is unresolved (less than 0.2 minutes in diameter) and represents emission from the central star seen through the circumstellar envelope

Are there plasminos in superconductors?

Hot and/or dense, normal-conducting systems of relativistic fermions exhibit a particular collective excitation, the so-called plasmino. We compute the one-loop self-energy, the dispersion relation and the spectral density for fermions interacting via attractive boson exchange. It is shown that plasminos also exist in superconductors.Comment: 15 pages, 14 figures, revte

Spatial heterodyne interferometry of VY Canis Major's, alpha Orionis, alpha Scorpii, and R leonis at 11 microns

Using the technique of heterodyne interferometry, measurements were made of the spatial distribution of 11 micron radiation from four late type stars. The circumstellar shells surrounding VY Canis Majoris, alpha Orionis, and alpha Scorpii were resolved, whereas that of R Leonis was only partially resolved at a fringe spacing of 0.4 sec

Automating reconfiguration chain generation for SRL-based run-time reconfiguration

Run-time reconfiguration (RTR) of FPGAs is mainly done using the configuration interface. However, for a certain group of designs, RTR using the shift register functionality of the LUTs is a much faster alternative than conventional RTR using the ICAP. This method requires the creation of reconfiguration chains connecting the run-time reconfigurable LUTs (SRL). In this paper, we develop and evaluate a method to generate these reconfiguration chains in an automated way so that their influence on the RTR design is minimised and the reconfiguration time is optimised. We do this by solving a constrained multiple travelling salesman problem (mTSP) based on the placement information of the run-time reconfigurable LUTs. An algorithm based on simulated annealing was developed to solve this new constrained mTSP. We show that using the proposed method, reconfiguration chains can be added with minimal influence on the clock frequency of the original design

Reconfigurable quadruple quantum dots in a silicon nanowire transistor

We present a novel reconfigurable metal-oxide-semiconductor multi-gate transistor that can host a quadruple quantum dot in silicon. The device consist of an industrial quadruple-gate silicon nanowire field-effect transistor. Exploiting the corner effect, we study the versatility of the structure in the single quantum dot and the serial double quantum dot regimes and extract the relevant capacitance parameters. We address the fabrication variability of the quadruple-gate approach which, paired with improved silicon fabrication techniques, makes the corner state quantum dot approach a promising candidate for a scalable quantum information architecture

Graphene microwave transistors on sapphire substrates

We have developed metal-oxide graphene field-effect transistors (MOGFETs) on sapphire substrates working at microwave frequencies. For monolayers, we obtain a transit frequency up to ~ 80 GHz for a gate length of 200 nm, and a power gain maximum frequency of about ~ 3 GHz for this specific sample. Given the strongly reduced charge noise for nanostructures on sapphire, the high stability and high performance of this material at low temperature, our MOGFETs on sapphire are well suited for a cryogenic broadband low-noise amplifier