Search results for "PASS"
showing 10 items of 1629 documents
La transformación nietzscheana del pensamiento según Deleuze
2015
Deleuze ve en Nietzsche a uno de los filósofos que con mayor eficacia crítica contradice la concepción clásica del pensamiento como búsqueda de la verdad y como ejercicio de amor a la verdad. Este artículo analiza el significado que para Deleuze tiene la oposición de Nietzsche a la tradición filosófica, que considera que el pensamiento quiere y ama la verdad de la que nos vemos alejados por la acción de fuerzas extrañas al pensamiento (procedentes del cuerpo, de las pasiones, de los intereses, etc.). De este modo se muestra de qué modo esas fuerzas que intervienen en el pensamiento remiten el pensamiento mismo a las fuerzas que le subyacen en cuanto pensamiento.
Influences of Structure and Composition on the Photoelectrochemical Behaviour of Anodic Films on Zr and Zr-20at.%Ti
2008
Abstract A photoelectrochemical investigation on anodic films of different thickness grown on sputter-deposited Zr and Zr–20 at.%Ti was carried out. The estimated optical band gap and flat band potential of thick ( U F ≥ 50 V) anodic films were related to their crystalline structure and compared with those obtained for thinner ( U F ≤ 8 V/SCE) anodic oxides having undetermined crystalline structure. The E g values obtained by photocurrent spectroscopy were also compared with the experimental band gap estimated by other optical ex situ techniques and with the available theoretical estimates of the zirconia electronic structures in an attempt to reconcile the wide range of band gap data rep…
Photocurrent Spectroscopy in Corrosion and Passivity Studies. A Critical Assessment
2016
Photocurrent Spectroscopy (PCS) is currently employed for the characterization of solid-state properties of semiconducting and insulating materials, since the knowledge of their band gap is a prerequisite to any possible application in different fields such as: solar energy conversion (photoelectrochemical and photovoltaic solar cells, photocatalysis) and microelectronics (high-k, high band-gap materials) (1-2). In the last 20-30 years an increasing number of scientists working in the area of corrosion has been attracted by this technique owing to its versatility and ability to scrutinize in situ corrosion layers and passive films having semiconducting or insulating behaviour. In previous w…
Photocurrent Spectroscopy Applied to the Characterization of Passive Films on Sputter-Deposited Ti-Zr Alloys
2008
Abstract A photoelectrochemical investigation on thin (⩽13 nm) mixed oxides grown on sputter-deposited Ti–Zr alloys of different composition by air exposure and by anodizing (formation voltage, UF = 4 V/SCE) was carried out. The experimental results showed that the optical band gap, E g opt , increases with increasing Zr content in both air formed and anodic films. Such behaviour is in agreement with the theoretical expectation based on the correlation between the band gap values of oxides and the difference of electronegativity of their constituents. The flat band potential of the mixed oxides was found to be almost independent on the Ti/Zr ratio into the film and more anodic with respect …
Photoelectrochemical investigation of passive layers formed on Fe in different electrolytic solutions
2004
Abstract The passive films formed on Fe in different electrolytic solutions, spanning almost the overall pH range, and with different growth procedures were investigated systematically by photocurrent spectroscopy. The potentiodynamic growth curves are compared both in aerated and de-aerated electrolytes and a potentiostatic growth procedure is also employed. For high positive formation potentials, similar anodic spectra are recorded in all solutions giving an optical gap very close to that expected for crystalline Fe2O3. The origin of photocurrent spikes is also investigated and the effect of the formation potential upon the measured absorption threshold is discussed taking into account th…
Study of passive films on stainless steels by photocurrent measurements
1990
Abstract Passive films formed on three different stainless steels have been studied by means of photocurrent spectroscopy. Differences in the photoelectrochemical behaviour have been attributed to the influence of the nickel content of the alloys and to the formation of different oxide phases.
A photocurrent spectroscopic investigation of passive films on chromium
1990
Abstract Photoelectrochemical experiments have been carried out in order to identify the passive layers grown on chromium metal in different conditions. Changes in the values of the band gap of the films have been related to changes of composition, due to the different water content of the films.
Physicochemical Characterization of Passive Films and Corrosion Layers by Differential Admittance and Photocurrent Spectroscopy
2009
Two different electrochemical techniques, differential admittance and photocurrent spectroscopy, for the characterization of electronic and solid state properties of passive films and corrosion layers are described and critically evaluated. In order to get information on the electronic properties of passive film and corrosion layers as well as the necessary information to locate the characteristic energy levels of the passive film/electrolyte junction like: flat band potential (Ufb), conduction band edge (EC) or valence band edge (EV), a wide use of Mott-Schottky plots is usually reported in corrosion science and passivity studies. It has been shown, in several papers, that the use of simpl…
Photocurrent spectroscopy of thin passive films
2002
Publisher Summary This chapter reviews theoretical background on the photoelectrochemistry of metal and semiconductor electrodes on which photocurrent spectroscopy (PCS) relies, by focusing particularly on new features that are typical of the photoelectrochemical behavior of thin passive films and usually absent in the behavior of bulk crystalline semiconductors. The chapter also highlights the advantages of PCS in getting in situ information on the structure of the metal-passive-film-electrolyte systems and shows a more recent quantitative use of this technique in characterizing the composition of passive films. The formation of a protective film on a metallic surface is a key step in esta…