32,319 research outputs found
Cat. n. I.26b. Pietro Santi Bartoli (attrib.) (Perugia, 1635-Roma, 1700), Allegorie di settembre, ottobre e novembre
No full textCat. n. I.27b. Francesco Bartoli (attrib.) (Roma 1670-1733), Allegoria di settembre (da Pietro Santi Bartoli)
No full textCat. n. I.26c. Pietro Santi Bartoli (attrib.) (Perugia, 1635-Roma, 1700), Planimetria dello scavo del 1693 presso la chiesa dei Letterati con iscrizione
No full textCat. n. I.27a. Francesco Bartoli (attrib.) (Roma 1670-1733), Parete affrescata con decorazioni in quarto stile dallo scavo di Palazzo Rospigliosi (1709)
No full textExperimental investigation into the effect of substrate clamping on the piezoelectric behaviour of thick-film PZT elements
No full textThis paper details an experimental investigation of the clamping effect associated with thick-film piezoelectric elements printed on a substrate. The clamping effect reduces the measured piezoelectric coefficient, d33, of the film. This reduction is due to the influence of the d31 component in the film when a deformation of the structure occurs, by either the direct or indirect piezoelectric effect. Theoretical analysis shows a reduction in the measured d33 of 62%, i.e. a standard bulk lead zirconate titanate (PZT)-5H sample with a manufacturer specified d33 of 593pC/N would fall to 227.8pC/N. To confirm this effect, the d33 coefficients of five thin bulk PZT-5H samples of 220µm thickness were measured before and after their attachment to a metallized 96% alumina substrate. The experimental results show a reduction in d33 of 74% from 529pC/N to 139pC/N. The theoretical analysis was then applied to existing University of Southampton thick-film devices. It is estimated that the measured d33 value of 131pC/N of the thick-film devices is the equivalent of an unconstrained d33 of 345pC/N
A Physics-Based Approach to Model Hot-Electron Trapping Kinetics in p-GaN HEMTs
No full textHot electron trapping can significantly modify the performance of GaN-based HEMTs during hard switching operation. In this letter, we present a physics-based model based on rate equations to model the trapping kinetics of hot-electrons in GaN transistors submitted to semi- ON-state stress. The model is validated through comparison with the experimental data, obtained by means of a pulsed-drain current transient setup developed ad-hoc. Hot-electron trapping is found to have logarithmic time dependence; the first 10 mu ext{s} of operation are critical in determining the current collapse during stress
THE ANOMALOUS FLUORESCENCE OF N,N-DIALKYL-P-CYANOANILINES
No full textPresent address of Omar S. Khalil: School of Chemistry, Rutgers University New Brunswick, New Jersey, 08903.Author Institution: Coates Chemical Laboratories, Louisiana State UniversityAbsorption and luminescence spectra of N,N-dialkyl-p-cyanoanilines in a variety of solvents are reported. Evidences for ``dimer” and ``excimer” formation are provided and the anomalous luminescences of these molecules, which exhibits three distinctly-different fluorescence emissions and two very dissimilar phosphorescence processes, are interpreted
Measurement of the branching fraction
No full textThe B
0
s
→ J/ψK
0
S
branching fraction is measured in a data sample corresponding to 0.41 fb−1
of integrated luminosity collected with the LHCb detector at the LHC. This channel is sensitive to
the penguin contributions affecting the sin 2β measurement from B
0
→ J/ψK
0
S
. The time-integrated
branching fraction is measured to be B(B
0
s
→ J/ψK
0
S
) = (1.83±0.28)×10−5
. This is the most precise
measurement to date
Far plasma wake of Titan from the RPWS observations: A case study
No full textThe Titan's plasma wake has been investigated using observations from the Radio and Plasma Wave Science (RPWS) instrument onboard the Cassini spacecraft during one Titan flyby on December 26, 2005. The Langmuir Probe and the wideband receiver suggest a strong asymmetry of the plasma wake, which is displaced from the ideal wake. Two distinct structures are identified inbound and outbound of the flyby with significantly different electron number densities (ne). The maximum electron number density reached 14 cm(-3) on the Saturn side, connected to the sunlit ionosphere, while on the opposite side of Saturn observations indicate a density smaller than 2 cm(-3). Other derived parameters of the Langmuir probe analysis suggest also a difference in plasma composition between the two structures, where heavy and light ions dominate the Saturn and anti- Saturn side respectively. The total ion outflow is estimated at 2-7 x 10(25) ions/s assuming a cylindrical geometry for the plasma wake
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