23,853 research outputs found
Characterization of bismuth titanate ceramics derived by mechanochemical synthesis
No full textBismuth titanate, Bi(4)Ti(3)O(12) (BIT) nanosized powders have been successfully synthesized via high energy mechanochemical activation. The phase formation of BIT, crystal structure, microstructure, crystallite size and specific surface area were followed by XRD, scanning electron microscopy (SEM) and the BET specific surface area measurements. The BIT milled 2 h shows the orthorhombic crystalline structure with small amount of amorphous phase. The microstructure of Bi(4)Ti(3)O(12) ceramics sintered at 1000 degrees C for 12h exhibit plate-like grain structure.Inst Phys, Belgrade 11001, SerbiaInst Multidisciplinary Res, Belgrade, SerbiaUNESP, Inst Quim, Araraquara, SP, BrazilUNESP, Inst Quim, Araraquara, SP, Brazi
Electron-proton collisions at a centre of mass energy of 200 GeV: proposal for a study for a Canadian electron ring at a high energy accelerator
No full text
Plethysms and interacting boson models
No full textA short review of the plethysm technique aiming to its application in finding branching rules for the reduction of an irreducible representation of a group under the restriction to one of its subgroups is given. The algebraic structure of the interacting boson model and some of its extensions is given together with the branching rules needed to classify their basis states, obtained by the use of plethysms. (C) 2003 American Institute of Physics.Univ Estadual Paulista, Inst Fis Teor, BR-01405900 São Paulo, BrazilLatvian State Univ, Inst Solid State Phys, Lab Radiat Phys, LV-2169 Salaspils, LatviaInst Theoret Phys & Astron, LT-2600 Vilnius, LithuaniaUniv Estadual Paulista, Inst Fis Teor, BR-01405900 São Paulo, Brazi
Probing supernova physics with neutrino oscillations
No full textWe point out that solar neutrino oscillations with large mixing angle as evidenced in current solar neutrino data have a strong impact on strategies for diagnosing collapse-driven supernova (SN) through neutrino observations. Such oscillations induce a significant deformation of the energy spectra of neutrinos, thereby allowing us to obtain otherwise inaccessible features of SN neutrino spectra. We demonstrate that one can determine temperatures and luminosities of non-electron flavor neutrinos by observing (υ) over bar (e) from galactic SN in massive water Cherenkov detectors by the charged current reactions on protons. (C) 2002 Elsevier B.V. B.V. All rights reserved.Tokyo Metropolitan Univ, Dept Phys, Hachioji, Tokyo 1920397, JapanUniv Estadual Paulista, Inst Fis Teor, BR-01405900 São Paulo, SP, BrazilMax Planck Inst Phys & Astrophys, Werner Heisenberg Inst Phys, D-80805 Munich, GermanyUniv Valencia, CSIC, Inst Fis Corpuscular, E-46071 Valencia, SpainUniv Estadual Paulista, Inst Fis Teor, BR-01405900 São Paulo, SP, Brazi
Freeze-out in hydrodynamical models in relativistic heavy ion collisions
No full textUniv Bergen, Sect Theoret Phys, N-5007 Bergen, NorwayKFKI Res Inst Particle & Nucl Phys, H-1525 Budapest, HungaryUniversidade Federal de São Paulo, Inst Fis, BR-05389970 São Paulo, SP, BrazilUniv Frankfurt, Inst Theoret Phys, D-60054 Frankfurt, GermanyUniv Fed Rio de Janeiro, Inst Fis, BR-21945970 Rio de Janeiro, BrazilUniversidade Federal de São Paulo, Inst Fis, BR-05389970 São Paulo, SP, BrazilWeb of Scienc
Equivalence of many-gluon Green's functions in the Duffin-Kemmer-Petieu and Klein-Gordon-Fock statistical quantum field theories
No full textWe prove the equivalence of many-gluon Green's functions in the Duffin-Kemmer-Petieu and Klein-Gordon-Fock statistical quantum field theories. The proof is based on the functional integral formulation for the statistical generating functional in a finite-temperature quantum field theory. As an illustration, we calculate one-loop polarization operators in both theories and show that their expressions indeed coincide.Univ Estadual Paulista, Inst Fis, São Paulo, BrazilPN Lebedev Phys Inst, Moscow 117924, RussiaUniv Estadual Paulista, Inst Fis, São Paulo, Brazi
Quantum Phase Transitions: Frustration can be critical
No full textMax Planck Inst Phys Komplexer Syst, Dresden, GermanySAIFR, ICTP, Sao Paulo, SP, BrazilUniv Estadual Paulista, Inst Fis Teor, Sao Paulo, SP, BrazilUniv Estadual Paulista, Inst Fis Teor, Sao Paulo, SP, Brazi
An approach to analyzing synthesis, structure and properties of bismuth titanate ceramics
No full textThe family of bismuth titanate, Bi(4)Ti(3)O(12) (BIT) layered-structured ferroelectrics materials is attractive from the viewpoint of such as their application as electronic materials dielectrics, piezoelectrics and pyroelectrics, because they are characterized by good stability of piezoelectric properties, a high Curie temperature and a good resistance vs temperature. Bismuth titanate (Bi(4)Ti(3)O(12)) powders can be prepared using different methods, depending if the creation will be film coating or ceramics. The structure and properties of bismuth titanate materials show a significance dependence on the applied synthesis method. In this review paper, we made an attempt to give an approach to analyszing the structure, synthesis methods and properties of bismuth titanate ferroelectrics materials.UNESP, Inst Quim, Araraquara, SP, BrazilInst Phys, Belgrade, Serbia MontenegUniv Belgrade, Ctr Multidisciplinary Studies, Belgrade, Serbia MontenegUNESP, Inst Quim, Araraquara, SP, Brazi
Irradiation induced pulsations of reverse biased metal oxide/silicon structures
No full textSpecific electronic features have been found in structures consisting of metal oxide layers on silicon substrates upon swift heavy ion irradiation. These features are linked to the appearance of radiation-induced negative differential resistances in the structures. in the reversed bias direction they show high frequency current pulsations at around similar to 10 kHz frequency. Their amplitude increases with increasing applied voltage. the pulsation frequency also shows a small increase. the current amplitude depends on the ion fluence and flux. (C) 2007 American Institute of Physics.Hahn Meitner Inst Berlin GmbH, D-14109 Berlin, GermanyBen Gurion Univ Negev, IL-84105 Beer Sheva, IsraelUniversidade Federal de São Paulo, BR-05508090 São Paulo, BrazilUniv Delhi, Dept Phys & Astrophys, Delhi 110007, IndiaS Ukrainian State Univ, UA-65008 Odessa, UkraineBelarusian State Univ, Minsk 22080, ByelarusInst Phys, UA-03028 Kiev, UkraineUniversidade Federal de São Paulo, BR-05508090 São Paulo, BrazilWeb of Scienc
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