Multi-Magnon Scattering in the Ferromagnetic XXX-Model with Inhomogeneities

We determine the transition amplitude for multi-magnon scattering induced through an inhomogeneous distribution of the coupling constant in the ferromagnetic XXX-model. The two and three particle amplitudes are explicitely calculated at small momenta. This suggests a rather plausible conjecture also for a formula of the general n-particle amplitude.Comment: 21 pages, latex, no figure

Resolution of the Nested Hierarchy for Rational sl(n) Models

We construct Drinfel'd twists for the rational sl(n) XXX-model giving rise to a completely symmetric representation of the monodromy matrix. We obtain a polarization free representation of the pseudoparticle creation operators figuring in the construction of the Bethe vectors within the framework of the quantum inverse scattering method. This representation enables us to resolve the hierarchy of the nested Bethe ansatz for the sl(n) invariant rational Heisenberg model. Our results generalize the findings of Maillet and Sanchez de Santos for sl(2) models.Comment: 25 pages, no figure

Simultaneous adsorptive cathodic stripping voltammetric determination of Nickel(II) and Cobalt(II) at the in-situ bismuth-modified gold electrode

A study on the simultaneous determination of Ni(II) and Co(II) dimethylglyoximates (Ni-DMG and Co-DMG) through adsorptive cathodic stripping voltammetry at an in situ bismuth-modified gold electrode (Bi-AuE) is reported. The key operational parameters, such as Bi(III) concentration, accumulation potential and accumulation time were optimized and the morphology of the Bi-microcrystals deposited on the Au-electrode was studied. The Bi- AuE allowed convenient analysis of trace concentrations of solely Ni(II) or of Ni(II) and Co(II) together, with cathodic stripping voltammograms characterized by well-separated stripping peaks. The calculated limit of detection (LOD) was 40 ngL1 for Ni(II) alone, whereas the LOD was 98 ngL1 for Ni(II) and 58 ngL1 for Co(II), when both metal ions were measured together. The optimized method was finally applied to the analysis of certified spring water (NIST1640a) and of natural water sampled in the Lagoon of Venice. The results obtained with the Bi- AuE were in satisfactory agreement with the certified values and with those provided by complementary techniques, i.e., ICP-OES and ICP-MS

Application of AC-SECM in Corrosion Science - Local visualisation of inhibitor films on active metals for corrosion protection

The suitability of frequency-dependent alternating-current scanning electrochemical microscopy (4D AC-SECM) for the investigation of the thin passivating layers covering the surface of corrosion-inhibited metals has been demonstrated. The inhibition of copper corrosion by benzotriazole (BTAH) and methyl-benzotriazole (MBTAH), which are effective inhibitors for this metal in many environmental conditions, was investigated. Strong dependencies were found for the AC z-approach curves with both the duration of the inhibitor treatment and the frequency of the AC excitation signal applied in AC-SECM. Both negative and positive feedback behaviours were observed in the AC approach curves for untreated copper and for Cu-BTAH and Cu-MBTAH samples. Negative feedback behaviour occurred in the low frequency range, whereas the positive feedback effect was observed at higher frequencies. A threshold frequency related to the passage from negative to positive regimes could be determined in each case. The value of the threshold frequency for inhibitor-modified samples was found always to be significantly higher than for the untreated metal, because the inhibitor film provides electrical insulation for the surface. Moreover, the threshold frequency increased with greater surface coverage by the inhibitor. 3D AC-SECM was successfully applied to visualizing spatially-resolved differences in the local electrochemical activity between inhibitor-free and inhibitor-covered areas of the sampl

A scanning electrochemical microscopy characterization of the localized corrosion reactions occurring on nitinol in saline solution after anodic polarization

Sensors and Actuators B: Chemical 321 (2020) 128610. https://doi.org/10.1016/j.snb.2020.12861