Uniaxial stress dependence of the permittivity of electroceramics

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Two main factors govern the ingress of chloride ions into concrete reinforced with ordinary steel reinforcement, from de-icing salts: (1) the cover concrete (permeability, thickness), and (2) the microclimatic conditions (humidity, temperature, concentration of de-icing salts) at the concrete surface. A numerical model of chloride transport, taking into consideration environmental conditions (temperature, humidity, snow, rain and salt spreading), was used to predict the chloride profiles in concrete represe

It is shown that a strong but diffuse dielectric anomaly, commonly expected only in disordered ferroelectrics, may be inherent in strained and defect-free perovskite ferroelectric thin films. The origin of this unusual anomaly, which was never predicted for a defect-free system, is the overcritical trace of a critical point in the film phase diagram, This possibility is illustrated by the mean-field thermodynamic calculations performed for (111)-oriented PbTiO3 films epitaxially grown on dissimilar cubic su

Pb(Zr,Ti)O-3 (PZT) and Pb(Zr,Ti,Nb)O-3 (PNZT) thin films were grown on platinized silicon substrates by r.f. magnetron sputtering followed by a post-annealing treatment. The Niobium, Nb, concentration varied from 1 to 7 at.% by increment of 1 at.%. The effects of the Nb introduction on the PZT electrical properties, i.e, dielectric, ferroelectric and piezoelectric ones were investigated. The relative dielectric constant (epsilon (T)) was very sensitive to the Nb introduction; epsilon (T) reaches 1100 for a

Electromechanical properties of a number of ferroelectric films including PbZrxTi1-xO3(PZT), 0.9PbMg(1/3)Nb(2/3)O(3)-0.1PbTiO(3)(PMN-PT), and SrBi2Ta2O9(SBT) are investigated using laser interferometry combined with conventional dielectric measurements. Effective electrostriction coefficients of the films, Q(eff), are determined using a linearized electrostriction equation that couples longitudinal piezoelectric coefficient, d(33), with the polarization and dielectric constant. It is shown that, in PZT film

A detailed investigation of the constitutive behavior of the International Energy Agency (IEA) program heat of 8 Cr unirradiated F82H ferritic-martensitic steel has been undertaken in the temperature range of 80-723 K. The overall tensile flow stress is decomposed into temperature-dependent and athermal yield stress contributions plus a mildly temperature-dependent strain-hardening component. The fitting forms are based on a phenomenological dislocation mechanics model. This formulation provides a more accu

We present a new type of microinstrument allowing manipulation and mechanical perturbation of individual cells under an optical microscope. These instruments, which we call microplates, are pulled from rectangular glass bars. They have flat tips, typically 2 microm thick x 20 microm wide, whose specific shape and stiffness can be adjusted through the pulling protocol. After appropriate chemical treatment, microplates can support cell adhesion and/or spreading. Rigid microplates are used to hold cells, where

Mechanisms of polarization switching and fatigue in (Pb, La)(Zr, Ti)O-3 (PLZT) films are studied by comparative analysis of degradation and leakage conduction of PLZT capacitors with Pt, SrRuO3 (SRO), and layered Pt/SRO (80/5 nm) electrodes. It is found that the asymmetrical Pt/SRO/PLZT/Pt structure exhibits a good fatigue performance in combination with low leakage like that on identically processed Pt/PLZT/Pt capacitor. This asymmetrical structure exhibits very unusual dependence of the endurance of switc

A surprising non-cumulative effect of the degradation mechanism (fatigue) of the switched polarization (P-r(s)), was observed in MOCVD and sol-gel prepared Pb(Zr0.47Ti0.53)O-3 (PZT) ferroelectric thin films capacitors (FECAP) with Pt-electrodes. This effect is a manifestation of the ability of the suppression mechanism of P-r(s) to self-adjust to the fatiguing field. Experimentally this was shown by performing two consecutive fatigue procedures on the same capacitor. The field used in the first procedure wa

The weak-field dielectric properties of ordered, disordered, and lead-deficient disordered Pb(Sc0.5Ta0.5)O-3 (PST) ceramics (PST-O, PST-D, and PST-DV, respectively) were investigated under various de-bias conditions. The de-bias field influences the paraelectric-to-ferroelectric transition in PST-O and the relaxor-to-normal-ferroelectric transition in disordered PST-D, Phase diagrams, with respect to de bias and temperature, were proposed for ordered and disordered PST materials. A field-induced ferroelectr

The concept of reaction invariants is extended to include flow invariants of chemical-reaction systems with inlet and outlet streams. A transformation to normal form is introduced that allows the separation of (1) the evolution of the independent reactions, (2) the influence of inlet streams, and (3) the behavior of the reaction and flow invariants. In the light of this transformation to normal form, model reduction, state accessibility, state reconstruction, and feedback linearizability are analyzed.

The effects of niobium doping on the hysteresis parameters of sol-gel Pb-1.1-x/2(Zr0.53Ti0.47)(1-x)NbxO3 (0 < x < 0.05) have been reported fbr two sets of films with analogous grain size and degree of (111) texture but with different surface microstructures. For both sets, a strong continuous decay of the remnant and maximum polarizations and slope of the hysteresis loop at the coercive field was observed with increasing niobium concentration. The held dependence of the remnant polarization for any given ni

This study describes the spatial heterogeneousness of the chemical composition of underground waters, particularly the trace elements, and the carbon-13 isotope in several carbonate aquifers of the alpine belt in Europe. The research forms part of the AQUITYP project which have been worked on the last 14 years by the Geology laboratory of the Swiss Federal Institute of Technology in Lausanne (GEOLEP). The main aim of the project is to define the typology of the aquifers, based on the chemical characterisati

Uniaxial stress dependence of the permittivity of electroceramics

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Chloride penetration model considering the microclimate

Strain-induced diffuse dielectric anomaly and critical point in perovskite ferroelectric thin films

Ferroelectric and piezoelectric properties of Nb doped PZT films

Characterization of the effective electrostriction coefficients in ferroelectric thin films

Constitutive behavior and fracture toughness properties of the F82H ferritic/martensitic steel

Microplates: a new tool for manipulation and mechanical perturbation of individual cells

Top-interface-controlled switching and fatigue endurance of (Pb, La)(Zr,Ti)O-3 ferroelectric capacitors

Field-adjusted suppression of the switching polarization in ferroelectric PZT thin films with Pt-electrodes

Dielectric properties of complex perovskite lead scandium tantalate under dc bias

Reaction and Flow Variants/Invariants in Chemical Reaction Systems with Inlet and Outlet Streams

Use of ferroelectric hysteresis parameters for evaluation of niobium effects in lead zirconate titanate thin films

Typologie géochimique des eaux des aquifères carbonatés des chaînes alpines d'Europe centrale et méridionale