Search results for "Negativity"

Semiempirical Correlation between Optical Band Gap Values of Oxides and the Difference of Electronegativity of the Elements. Its Importance for a Qua…

1997

A semiempirical correlation between the optical band gap of binary oxides and the difference of electronegativity between the oxygen and metallic elements (Pauling's extraionic energy) is proposed. In the frame of the proposed correlation an estimate of the repulsive term in the total lattice energy of ionic oxides is obtained in very good agreement with the existing data. An extension of the correlation to the ternary oxides and hydroxides is proposed by using the concept of average cationic or anionic group electronegativity. The usefulness of the proposed correlation for the in situ characterization of passive films on metals and alloys by photocurrent spectroscopy is illustrated by repo…

A Simple Model for the Photoelectrochemical Behavior of Corrosion Layers with Variable Hydration Degree

2002

Abstract With the goal of quantitatively applying photocurrent spectroscopy to corrosion studies, the photoelectrochemical behavior of layered passive films having a decreasing hydration/hydroxylation degree, from the solution interface toward the metal interface, has been modeled. The model makes use of the correlations between optical gap and electronegativity of the constituents previously proposed for surface oxides and hydroxides. In this paper, the model was tested successfully against the experimental data pertaining to three high band gap insulating oxide-forming metals, like Zr, Al, and Y. In the first case, the fitting of the experimental spectra was compatible with the occurrence…

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 …

Recent advances in photocurrent spectroscopy of passive films

2003

Abstract The quantitative application of photocurrent spectroscopy (PCS) for the in-situ determination of the composition of passive films and corrosion layers is reviewed in the light of recent theoretical advances, that have allowed to relate the measured optical gaps to the Pauling electronegativities of the film components. The correlations derived are tested versus recent experimental results regarding mixed oxides, anhydrous passive films on metallic alloys and hydroxide layers. The effect of the eventual long-range disorder into the passive film on the optical band gap values is also discussed. New experimental evidence reported for mixed d,d-metal oxides and passive films on sp,d-me…

Bounds on mixed state entanglement

2020

In the general framework of d 1 &times

2015

The recently proposed Wigner function for a particle in an infinite lattice [NJP 14, 103009 (2012)] is extended here to include an internal degree of freedom, as spin. The formalism is developed to account for dynamical processes, with or without decoherence. We show explicit solutions for the case of Hamiltonian evolution under a position-dependent potential, and for evolution governed by a master equation under some simple models of decoherence. Discrete processes are also discussed. Finally we discuss the possibility of introducing a negativity concept for the Wigner function in the case in which the spin degree of freedom is included.

Forward hadron production in pA collisions beyond leading order

2017

In this talk, we report our recent progress on pinning down the cause of negativity in the NLO single inclusive hadron production in pA collisions at forward rapidity.

Noiseless Conditional Teleportation of a Single Photon

2014

We experimentally demonstrate the noiseless teleportation of a single photon by conditioning on quadrature Bell measurement results near the origin in phase space and thereby circumventing the photon loss that otherwise occurs even in optimal gain-tuned continuous-variable quantum teleportation. In general, thanks to this loss suppression, the noiseless conditional teleportation can preserve the negativity of the Wigner function for an arbitrary pure input state and an arbitrary pure entangled resource state. In our experiment, the positive value of the Wigner function at the origin for the unconditional output state, W(0,0) = 0.015 $\pm$ 0.001, becomes clearly negative after conditioning, …

Psychological and physiological influences in chord progression including the prohibitions

2009

Harmony is one of three major elements in the music. Harmonics are the basic theory of composition. There are several kinds of prohibitions in relation to the chord progression in the rules of Harmonics. When composers compose music pieces, they pay attention not to contain these prohibitions. The prohibitions are empirically- defined with giving the musical expressions to melody processes by try and error. Even so, there are few studies that are quantitatively examined the perceptual effect of the prohibitions. Therefore, the authors have investigated the perceptual effects of the prohibition quantitatively. The present study deals with the psychological tests and the physiological measure…