Browsing Exact and Earth Sciences by Author "Jornada, Joao Alziro Herz da"
Now showing items 1-17 of 17
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Apparatus for processing of samples at high pressures and high temperatures in a fast quenching-rate regime and synthesis of polyacetylene by pulsed laser heating of confined carbon thin films
Andreazza, Marcos Luiz; Perottoni, Claudio Antonio; Jornada, Joao Alziro Herz da (2011) [Journal article]The pulsed laser heating of confined samples followed by ultrafast cooling constitutes an interesting route to explore the production of new phases and compounds. Indeed, in some cases the ultrafast cooling allows retaining ... -
Compression mechanism and pressure-induced amorphization of [upsilon]-ZrW/sub 2/O/sub 8/
Figueiredo, Camila Araújo de; Catafesta, Jadna; Zorzi, Janete Eunice; Souza, Leonardo Salvador; Baumvol, Israel Jacob Rabin; Gallas, Marcia Russman; Jornada, Joao Alziro Herz da; Perottoni, Claudio Antonio (2007) [Journal article]The structure of [upsilon]-ZrW2O8 has been optimized at zero pressure and also at V/V0=0.97 by means of density functional theory calculations using the B3LYP functional. As previously found for [upsilon]-ZrW2O8, tungsten ... -
Effects of high pressure on the electric field gradient in sp metals
Jornada, Joao Alziro Herz da; Zawislak, Fernando Claudio (1979) [Journal article]The effect of high pressure on the electric field gradient (EFG) present at 111Cd impurity nuclei in sp host metals of Zn, In, β-Sn, and TI has been measured by the time-differential perturbed angular correlation technique. ... -
Electric field gradients and impurity distributions in doped noble metals : a systematic study
Baumvol, Israel Jacob Rabin; Behar, Moni; Jornada, Joao Alziro Herz da; Livi, Rogerio Pohlmann; Lodge, Kenneth William; Zawislak, Fernando Claudio; Lopez Garcia, A. (1980) [Journal article]The electric field gradients created at 111Cd nuclei by dilute transition-element impurities in noble metais are studied by the technique of time-differential perturbed angular correlation. The present results supplement ... -
Evaluation of the adhesion strength of diamond films brazed on K-10 type hard metal
Santos, Sergio Ivan dos; Casanova, Carlos Alberto Medeiros; Teixeira, Cleiton Rodrigues; Balzaretti, Naira Maria; Jornada, Joao Alziro Herz da (2004) [Journal article]The coating of cutting tools with diamond films considerably increases the tool performance due to the combination of the unique tribological properties of diamond with the bulk properties of the substrate (toughness). The ... -
First-principles calculation of the structure and elastic properties of a 3D-polymerized fullerite
Perottoni, Claudio Antonio; Jornada, Joao Alziro Herz da (2002) [Journal article]In this paper we present results obtained from first-principles calculations concerning the crystal structure and elastic properties of a three-dimensional-polymerized fullerite. The orthorhombic structure we studied was ... -
Hardness and elasticity in cubic ruthenium dioxide
Leger, Jean Michel; Djemia, P.; Ganot, F.; Haines, Julian; Pereira, Altair Soria; Jornada, Joao Alziro Herz da (2001) [Journal article]The Knoop hardness of the highly incompressible cubic phase of ruthenium dioxide was found to be 19–20 GPa from indentation tests. This value scales well with the shear modulus approximated by the elastic constant C44 of ... -
A influência do sistema de gestão de laboratórios nos resultados dos ensaios de proficiência da construção civil
Pizzolato, Morgana; Ten Caten, Carla Schwengber; Jornada, Joao Alziro Herz da (2008) [Journal article]A participação de laboratórios em atividades de ensaio de proficiência (EP) é uma das formas de avaliar e demonstrar a confiabilidade das suas atividades de medição. Isso significa dizer que, por intermédio dos ensaios de ... -
Moldagem por injeção em baixa pressão de peças complexas de cerâmicas avançadas produzidas com pós submicrométricos
Zorzi, Janete Eunice; Perottoni, Claudio Antonio; Jornada, Joao Alziro Herz da (2004) [Journal article] -
Phase diagram of the heavy fermion system YbFe/sub 2/Ge/sub 2/ under pressure
Larrea Jiménez, Julio Antonio; Fontes, Magda Bittencourt; Baggio-Saitovitch, E.; Plessel, Jochen; Abd-Elmeguid, Mohsen M.; Ferstl, Julia; Geibel, Christoph; Pereira, Altair Soria; Jornada, Joao Alziro Herz da; Continentino, Mucio Amado (2006) [Journal article]The phase diagram of the heavy fermion compound YbFe2Ge2 under high pressures P ≤ 18.2 GPa was obtained by electrical resistivity measurements. Pressure drives the system from a paramagnetic Fermi liquid state to a ... -
Phase separation in ion bombarded feni invar alloys
Gallas, Marcia Russman; Amaral, Livio; Jornada, Joao Alziro Herz da (1991) [Journal article]Studies of the effects of ion bombardment on the phase equilibria and ordering of FeNi alloys with 30.6 and 39.5 at. % Ni were performed. The FeNi samples were bombarded with Ne, Ar, and Kr at different doses and temperatures, ... -
Piston-cylinder apparatus for high-pressure impedance spectroscopy
Hinrichs, Ruth; Jornada, Joao Alziro Herz da (1997) [Journal article]A simple piston–cylinder apparatus was developed for impedance spectroscopy at pressures up to 3 GPa and temperatures up to 500 °C. The apparatus is of the compound cylinder type, with the innermost cylinder made of a ... -
Pressure dependence of the refractive index of monoclinic and yttria-stabilized cubic zirconia
Balzaretti, Naira Maria; Jornada, Joao Alziro Herz da (1995) [Journal article]The pressure dependence of the refractive index of monoclinic and yttria-stabilized cubic zirconia was measured up to 3 and 8 GPa, respectively, using an interferometric method with the diamond-anvil cell. The experimental ... -
Pressure-induced self-insertion reaction in CoSb/sub 3/
Kraemer, Airton Carlos; Gallas, Marcia Russman; Jornada, Joao Alziro Herz da; Perottoni, Claudio Antonio (2007) [Journal article]The thermoelectric material CoSb3, with skutterudite structure, was subjected to high pressures using a diamond anvil cell up to 40 GPa. Above 20 GPa this compound undergoes an irreversible isosymmetric transition to a ... -
Pressure induced water insertion in the defect pyrochlore nh/sub 4/nbwo/sub 6/
Perottoni, Claudio Antonio; Jornada, Joao Alziro Herz da (1997) [Journal article]A sudden and reversible increase of about 5% in the unit cell volume of ammonium tungstoniobate at pressures around 2.5 GPa was observed with pressure transmitting media containing water. This behavior was attributed to ... -
Processing of amorphous carbon films by ultrafast temperature treatment in a confined geometry
Lenz, Jorge Alberto; Perottoni, Claudio Antonio; Balzaretti, Naira Maria; Jornada, Joao Alziro Herz da (2001) [Journal article]A pressure cell with an anvil made of sapphire and the other made of tungsten carbide, was constructed to process thin film samples using a high power Nd:YAG pulsed laser, in a regime of ultrafast quenching rate and confined ... -
Variation of the refractive index and polarizability of sapphire under high pressures
Balzaretti, Naira Maria; Denis, J.P.; Jornada, Joao Alziro Herz da (1993) [Journal article]In this article we present the experimental results for the pressure variation of the refractive index of sapphire up to 16 GPa, obtained with an interferometric method, using the diamond anvil cell. In the range of ...