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Random Electric Field Instabilities of Relaxor Ferroelectrics
(2017-06-13)
Relaxor ferroelectrics are complex oxide materials which are rather unique to study the effects of compositional disorder on phase transitions. Here, we study the effects of quenched cubic random electric fields on the ...
Tsunamis and tsunami prepardness in Costa Rica, Central America
(2005-12)
Pacific and Atlantic sides of Costa Rica there are coastal segments characterised by a flat relief, which increases the vulnerability of the coastal communities. In addition to tsunamis originating in the Middle American ...
Tsunamis and Tsunami Hazards in Central America
(2000-02)
A tsunami catalogue for Central America is compiled containing 49 tsunamis for the
period 1539–1996, thirty seven of them are in the Pacific and twelve in the Caribbean. At the Caribbean side, 5 events are related with ...
Stochastic approach to the smart quantum confinement model in porous silicon
(Surface Science 515 (2002) L509-L513, 2002)
A model that encompasses two approaches to explain the photoluminescence in p-type porous silicon is proposed. The model considers a stochastic distribution of nanocrystallite sizes within the porous matrix and explain the ...
Estimation of Silicon Nanocrystalline Sizes from Photoluminescence Measurements of RF Co-Sputtered Si/SiO2 Films
(Materials Research Society Symposium Proceedings 737 (2003), 2003)
A stochastic distribution of nanocrystalline sizes model is applied to fit photoluminescence
(PL) spectra of luminescent Si nanocrystals in a Si/SiO2 matrix synthesized by RF co-sputtering
on the top of quartz substrates. ...
Electronic structure of silicon-based nanostructures
(2007-08-30)
We have developed a unifying tight-binding Hamiltonian that can account for the electronic properties of recently proposed Si-based nanostructures, namely, Si graphene-like sheets and Si nanotubes. We considered the sp3s∗ ...
The 2:3:6 quasi-periodic oscillation structure in GRS 1915+105 and cubic subharmonics in the context of relativistic discoseismology
(Monthly Notices of the Royal Astronomical Society 440:3011-3015, 2014-06-01)
We propose a simple toy model to explain the 2:3:6 quasi-periodic oscillation (QPO) structure in GRS 1915+105 and, more generally, the 2:3 QPO structure in XTE J1550−564, GRO J1655−40 and H1743−322. The model exploits the ...
Large isotropic negative thermal expansion above a structural quantum phase transition
(2015-10-01)
Perovskite structured materials contain myriad tunable ordered phases of electronic and magnetic origin with proven technological importance and strong promise for a variety of energy solutions. An always-contributing ...
Why is the electrocaloric effect so small in ferroelectrics?
(2016-05-19)
Ferroelectrics are attractive candidate materials for environmentally friendly solid state refrigeration free of greenhouse gases. Their thermal response upon variations of external electric fields is largest in the vicinity ...
The mechanical career of Councillor Orffyreus, confidence man
(2013-05)
In the early 18th century, J. E. E. Bessler, known as Orffyreus, constructed several wheels that he claimed could keep turning forever, powered only by gravity. He never revealed the details of his invention, but he ...