7,869 research outputs found
Alternative Buffer-Layers for the Growth of SrBi2Ta2O9 on Silicon
In this work we investigate the influence of the use of YSZ and CeO2/YSZ as
insulators for Metal- Ferroelectric-Insulator-Semiconductor (MFIS) structures
made with SrBi2Ta2O9 (SBT). We show that by using YSZ only the a-axis oriented
Pyrochlore phase could be obtained. On the other hand the use of a CeO2/YSZ
double-buffer layer gave a c-axis oriented SBT with no amorphous SiO2 inter-
diffusion layer. The characteristics of MFIS diodes were greatly improved by
the use of the double buffer. Using the same deposition conditions the memory
window could be increased from 0.3 V to 0.9 V. From the piezoelectric response,
nano-meter scale ferroelectric domains could be clearly identified in SBT thin
films.Comment: 5 pages, 9 figures, 13 refernece
Metallopolymer Organohydrogels with Photo-Controlled Coordination Crosslinks Work Properly Below 0 degrees C
Dynamics of quartz tuning fork force sensors used in scanning probe microscopy
We have performed an experimental characterization of the dynamics of
oscillating quartz tuning forks which are being increasingly used in scanning
probe microscopy as force sensors. We show that tuning forks can be described
as a system of coupled oscillators. Nevertheless, this description requires the
knowledge of the elastic coupling constant between the prongs of the tuning
fork, which has not yet been measured. Therefore tuning forks have been usually
described within the single oscillator or the weakly coupled oscillators
approximation that neglects the coupling between the prongs. We propose three
different procedures to measure the elastic coupling constant: an
opto-mechanical method, a variation of the Cleveland method and a thermal noise
based method. We find that the coupling between the quartz tuning fork prongs
has a strong influence on the dynamics and the measured motion is in remarkable
agreement with a simple model of coupled harmonic oscillators. The precise
determination of the elastic coupling between the prongs of a tuning fork
allows to obtain a quantitative relation between the resonance frequency shift
and the force gradient acting at the free end of a tuning fork prong.Comment: 16 pages, 6 figures, 2 Table
Experiences influencing walking football initiation in 55-75 year-old adults
Adults aged 55 and older are least likely to play sport. Despite research suggesting this population experiences physical and psychological benefits when doing so, limited research focuses on older adult sport initiation, especially in âadapted sportsâ such as walking football. The aim of this study was to explore initiation experiences of walking football players between 55 and 75 years old. Semistructured interviews took place with 17 older adults playing walking football for 6 months minimum ( Mage = 64). Inductive analysis revealed six higher order themes representing preinitiation influences. Eight further higher order themes were found, relating to positive and negative experiences during initiation. Fundamental influences preinitiation included previous sporting experiences and values and perceptions. Emergent positive experiences during initiation included mental development and social connections. Findings highlight important individual and social influences when initiating walking football, which should be considered when encouraging 55- to 75-year-old adults to play adapted sport. Policy and practice recommendations are discussed
Deep radio images of the HEGRA and Whipple TeV sources in the Cygnus OB2 region
Context. The modern generation of Cherenkov telescopes has revealed a new
population of gamma-ray sources in the Galaxy. Some of them have been
identified with previously known X-ray binary systems while other remain
without clear counterparts a lower energies. Our initial goal here was
reporting on extensive radio observations of the first extended and yet
unidentified source, namely TeV J2032+4130. This object was originally detected
by the HEGRA telescope in the direction of the Cygnus OB2 region and its nature
has been a matter of debate during the latest years.
Aims. We aim to pursue our radio exploration of the TeV J2032+4130 position
that we initiated in a previous paper but taking now into account the latest
results from new Whipple and MILAGRO TeV telescopes.
Methods. Our investigation is mostly based on interferometric radio
observations with the Giant Metre Wave Radio Telescope (GMRT) close to Pune
(India) and the Very Large Array (VLA) in New Mexico (USA). We also conducted
near infrared observations with the 3.5 m telescope and the OMEGA2000 camera at
the Centro Astronomico Hispano Aleman (CAHA) in Almeria (Spain).
Results. We present deep radio maps centered on the TeV J2032+4130 position
at different wavelengths. In particular, our 49 and 20 cm maps cover a field of
view larger than half a degree that fully includes the Whipple position and the
peak of MILAGRO emission. Our most important result here is a catalogue of 153
radio sources detected at 49 cm within the GMRT antennae primary beam with a
full width half maximum (FWHM) of 43 arc-minute. Moreover, our
multi-configuration VLA images reveal the non-thermal extended emission
previously reported by us with improved angular resolution.Comment: 10 pages, 8 figures, 1 online catalogue. Accepted for publication in
Astronomy & Astrophysic
Light-Switchable Polymer Adhesive Based on Photoinduced Reversible Solid-to-Liquid Transitions
Elastic Superhydrophobic and Photocatalytic Active Films Used as Blood Repellent Dressing
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