14,998 research outputs found
Interaction of molecular nitrogen with Free-Electron-Laser radiation
We compute molecular continuum orbitals in the single center expansion
scheme. We then employ these orbitals to obtain molecular Auger rates and
single-photon ionization cross sections to study the interaction of N2 with
Free-Electron-Laser (FEL) pulses. The nuclei are kept fixed. We formulate rate
equations for the energetically allowed molecular and atomic transitions and we
account for dissociation through additional terms in the rate equations.
Solving these equations for different parameters of the FEL pulse, allows us to
identify the most efficient parameters of the FEL pulse for obtaining the
highest contribution of double core hole states (DCH) in the final atomic ion
fragments. Finally we identify the contribution of DCH states in the electron
spectra and show that the DCH state contribution is more easily identified in
the photo-ionization rather than the Auger transitions
Adaptation may cause some of the face caricature effect
One of the ways to demonstrate a caricature preference is to ask participants to adjust a face image over a range from anti-caricature to caricature until it shows the best likeness to a specific individual. Since facial adaptation, whereby exposure to a face influences subsequent perception of faces, is rapid, it is possible that adaptation promotes the selection of a caricatured image. We tested whether giving participants a reference average face image, to counteract any adaptation, would reduce the degree of caricature selected for famous faces. Results confirmed a significant decrease, but even without an average, participants chose an anti-caricatured image. These data suggest a role for adaptation in generating caricature preferences while also suggesting such preferences are not inevitable
The measurement of low pay in the UK labour force survey
Consideration of the National Minimum Wage requires estimates of the distribution of hourly pay. The UK Labour Force Survey (LFS) is a key source of such estimates. The approach most frequently adopted by researchers has been to measure hourly earnings from several questions on pay and hours. The Office for National Statistics is now applying a new approach, based on an alternative more direct measurement introduced in March 1999. These two measures do not produce identical values and this paper investigates sources of discrepancies and concludes that the new variable is more accurate. The difficulty with using the new variable is that it is only available on a subset of respondents. An approach is developed in which missing values of the new variable are replaced by imputed values. The assumptions underlying this imputation approach and results of applying it to LFS data are presented. The relation to weighting approaches is also discussed
High performance photonic microwave filters based on a 50GHz optical soliton crystal Kerr micro-comb
We demonstrate a photonic radio frequency (RF) transversal filter based on an
integrated optical micro-comb source featuring a record low free spectral range
of 49 GHz yielding 80 micro-comb lines across the C-band. This record-high
number of taps, or wavelengths for the transversal filter results in
significantly increased performance including a QRF factor more than four times
higher than previous results. Further, by employing both positive and negative
taps, an improved out-of-band rejection of up to 48.9 dB is demonstrated using
Gaussian apodization, together with a tunable centre frequency covering the RF
spectra range, with a widely tunable 3-dB bandwidth and versatile dynamically
adjustable filter shapes. Our experimental results match well with theory,
showing that our transversal filter is a competitive solution to implement
advanced adaptive RF filters with broad operational bandwidths, high frequency
selectivity, high reconfigurability, and potentially reduced cost and
footprint. This approach is promising for applications in modern radar and
communications systems.Comment: 19 pages, 12 figures, 107 reference
Hot melt adhesive attachment pad
A hot melt adhesive attachment pad for releasably securing distinct elements together is described which is particularly useful in the construction industry or a spatial vacuum environment. The attachment pad consists primarily of a cloth selectively impregnated with a charge of hot melt adhesive, a thermo-foil heater, and a thermo-cooler. These components are securely mounted in a mounting assembly. In operation, the operator activates the heating cycle transforming the hot melt adhesive to a substantially liquid state, positions the pad against the attachment surface, and activates the cooling cycle solidifying the adhesive and forming a strong, releasable bond
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