Electrical performance of Ti/Pt thin films on glass-ceramic substrates after high temperature loading

In this study, the influence of post-deposition annealings (PDA) up to temperatures of T _PDA=700°C on the room-temperature resistivity of e-beam evaporated titanium/platinum (Ti/Pt) bi-layers on low temperature co-fired (LTCC) substrates covered with a glass encapsulate is investigated. The thickness of the platinum top layer is varied between 24 and 95 nm (titanium film thickness: 5 nm) and between 23 and 90 nm (titanium film thickness: 15 nm), respectively. In the “as-deposited” state and up to post-deposition annealing temperatures of T _PDA=450°C, the film resistivity is linearly correlated with the reciprocal value of the platinum film thickness according to the size effect. When applying, however, solely the Fuchs-Sondheimer model for evaluation, the effective mean free path for electrons is substantially above the value reported for crystalline platinum at room temperature. Compared to similar investigations on smooth Si/SiO₂ substrates yielding interpretable results within this theoretical approach, this is due to the increase of the thickness-dependent fraction in film resistivity which is strongly affected by the enhanced LTCC/glass surface roughness. At T _PDA>600°C, diffusion of titanium into the platinum top layer and the roughening of the LTCC/glass substrate dominate the electrical behavior, both causing an increase in film resistivity above average. In contrast to Si/SiO₂ substrates, thermal induced grooving effects in the Pt top layer play a minor role as the temperature coefficients of expansion of metallization and glass-ceramic substrate match better and the effective temperature difference for stress generation is lower due a glass softening temperature of about 450°C.     

Phase transition to hyperon matter in neutron stars

Recent progress in the understanding of the high density phase of neutron stars advances the view that a substantial fraction of the matter consists of hyperons. The possible impacts of a highly attractive interaction between hyperons on the properties of compact stars are investigated. We find that a hadronic equation of state with hyperons allows for a first order phase transition to hyperonic matter. The corresponding hyperon stars can have rather small radii of R approximately equal 8 km.     

A measurement of the proton structure functions from neutrino-hydrogen and antineutrino-hydrogen charged-current interactions

Within the framework of the quark-parton model, the quark and anti-quark structure functions of the proton have been measured by fitting them to the distributions of the events in the Bjorkeny variable. The data used form the largest sample of neutrino and antineutrino interactions on a pure hydrogen target available, and come from exposures of BEBC to the CERN wide band neutrino and antineutrino beams. It is found that the ratiod _v /u _v of valence quark distributions falls with increasing Bjorkenx. In the context of the quark-parton model the results constrain the isospin composition of the accompanying diquark system. Models involving scattering from diquarks are in disagreement with the data.     

Breakdown of a topological phase: quantum phase transition in a loop gas model with tension

We study the stability of topological order against local perturbations by considering the effect of a magnetic field on a spin model--the toric code--which is in a topological phase. The model can be mapped onto a quantum loop gas where the perturbation introduces a bare loop tension. When the loop tension is small, the topological order survives. When it is large, it drives a continuous quantum phase transition into a magnetic state. The transition can be understood as the condensation of "magnetic" vortices, leading to confinement of the elementary "charge" excitations. We also show how the topological order breaks down when the system is coupled to an Ohmic heat bath and relate our results to error rates for topological quantum computations.     

Vocal Tract Configurations in Male Alto Register Functions

Purpose

Professional male altos (countertenors) mostly use a register function, which is considered to be derived from falsetto. However, the sound produced differs in professional altos compared with the modal register or falsetto of untrained voices. The aim of this study was to analyze differences of the vocal tract shapes in male alto register functions.

Material and Methods

Dynamic real-time magnetic resonance imaging of eight frames per second was used to analyze the vocal tract profile in seven professional male altos who sang on the vowel /a/, an ascending and descending scale from G3 (196 Hz) to E4 (330 Hz). The scale included their register transition from modal register to stage (counter) falsetto and naïve falsetto.

Results

Register transitions from modal register to stage falsetto were associated with increased lip opening, jaw retraction, elevation and back positioning of the tongue, pharynx narrowing, uvula elevation, drop of larynx height, and tilting of the larynx. Differences between stage and naïve falsetto were found mostly with regard to lip opening and pharynx width.

Conclusions

The differences between the vocal tract configurations might have an impact on the acoustic characteristics observed in professional male alto register functions.     

Crystalline Pr:SrAl12O19 waveguide laser in the visible spectral region

We fabricated waveguides in Pr:SrAl(12)O(19) crystals by direct femtosecond laser writing. The propagation losses were calculated to be as low as 0.16 dB/cm at a wavelength of 633 nm. Laser oscillation in a diode-pumped waveguide at a wavelength of 643.5 nm was realized. The output power of the waveguide laser was 28.1 mW at a slope efficiency of 8%.