202 research outputs found
Nanoscopic Tunneling Contacts on Mesoscopic Multiprobe Conductors
We derive Bardeen-like expressions for the transmission probabilities between
two multi-probe mesoscopic conductors coupled by a weak tunneling contact. We
emphasize especially the dual role of a weak coupling contact as a current
source and sink and analyze the magnetic field symmetry. In the limit of a
point-like tunneling contact the transmission probability becomes a product of
local, partial density of states of the two mesoscopic conductors. We present
expressions for the partial density of states in terms of functional
derivatives of the scattering matrix with respect to the local potential and in
terms of wave functions. We discuss voltage measurements and resistance
measurements in the transport state of conductors. We illustrate the theory for
the simple case of a scatterer in an otherwise perfect wire. In particular, we
investigate the development of the Hall-resistance as measured with weak
coupling probes.Comment: 10 pages, 5 figures, revte
Fabrication of arrays of lead zirconate titanate (PZT) nanodots via block copolymer self-assembly
This Article presents a simple methodology for the fabrication of two-dimensional arrays of lead zirconate titanate (PZT) nanodots on n-doped Si substrates via the directed self-assembly of PS-b-PEO block copolymer templates. The approach produces highly ordered PZT nanodot patterns, with lateral widths and heights as small as 20 and 10 nm, respectively, and a coverage density as high as âŒ68 Ă 109 nanodots cmâ2. The existence of a perovskite phase in the nanodots was confirmed by X-ray diffraction and X-ray photoelectron spectroscopy. The piezo-amplitude and ferroelectric domain response obtained from the nanodots, through piezoresponse force microscopy, confirmed the presence of ferroelectricity in the PZT arrays. Notably, PZT nanodots with a thickness âŒ10 nm, which is close to the critical size limit of PZT, showed ferroelectric behavior. The presence of a multi-a/c domain structure in the nanodots was attributed to their polycrystalline nature
Special Libraries, April 1933
Volume 24, Issue 3https://scholarworks.sjsu.edu/sla_sl_1933/1002/thumbnail.jp
Fabrication of Relaxer-Based Piezoelectric Energy Harvesters Using a Sacrificial Poly-Si Seeding Layer
Gardens of happiness: Sir William Temple, temperance and China
This is the author accepted manuscript. The final version is available from Taylor & Francis via the DOI in this recordSir William Temple, an English statesman and humanist, wrote âUpon the
Gardens of Epicurusâ in 1685, taking a neo-epicurean approach to happiness
and temperance. In accord with Pierre Gassendiâs epicureanism, âhappinessâ is
characterised as freedom from disturbance and pain in mind and body, whereas
âtemperanceâ means following nature (Providence and oneâs physiopsychological constitution). For Temple, cultivating fruit trees in his garden was
analogous to the threefold cultivation of temperance as a virtue in the humoral
body (as food), the mind (as freedom from the passions), and the bodyeconomic (as circulating goods) in order to attain happiness. A regimen that was
supposed to cure the malaise of Restoration amidst a crisis of unbridled
passions, this threefold cultivation of temperance underlines Templeâs reception
of China and Confucianism wherein happiness and temperance are highlighted.
Thus Templeâs âgardens of happinessâ represent not only a reinterpretation of
classical ideas, but also his dialogue with China.European CommissionLeverhulme Trus
ZusammenhÀnge zwischen physikalischen und chemischen VorgÀngen bei der Muskelkontraktion
Which PZT thin films for piezoelectric microactuator applications?
The effective piezoelectric coefficient e(31) has been measured on sol-gel processed Pb(ZrxTi1-x)O-3 thin films with Zr concentrations ranging from 45 to 60%. The largest value was observed at 45% Zr, although dielectric constant and effective d(33) peak at 53% Zr. The findings suggest that the optimal composition for microactuators and sensors is less than 45% Zr, i.e., in the tetragonal part of the phase diagram
DC bias dependent shift of resonance frequencies in BST thin film membranes
DC bias dependent acoustic resonance phenomena have been observed in micromachined tunable thin film capacitors based on Ba0.3Sr0.7TiO3 (BST) thin films. The antiresonance frequency is only weakly dc bias dependent, whereas the resonance frequency exhibits a strong dependence on the applied dc bias. The resonance frequency shifted by 0.8% for a frequency of about 3.44 GHz and an applied of 333 KV/cm. At the same time the electromechanical coupling constant k(t)(2) increased to 1.8%. The experimental observations correlate well with the theoretical predictions derived from the free energy P expansion using Landau theory
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