Wagner polarization

When performing a Hebb-Wagner polarization experiment one has to take the following aspects into careful consideration ... 

M.D. Frogley, Q. Zhao, and H.D. Wagner, Polarized resonance Raman spectroscopy of single-wall carbon nanotubes within a polymer under strain. Phys. Rev. B 65, 113413.1-113413.4 (2002). 

In the second case (limit of fast kinetics at the gas-solid interface), the film becomes entirely bulk transport limited, corresponding to the limit of Hebb— Wagner polarization. Since electronic conduction is fast, this situation yields a Warburg impedance for finite length diffusion ... 

Mawell-Wagner polarization enhanced by fabric arrangement... 

H. Use of the Wagner Polarization Parameter to Estimate Qualitatively the Uniformity of Current Distribution... 

The behavior of the relaxation times as a function of temperature for aniline in CPG of 7,5 nm pore size are depicted in Fig. 3. For temperatures greater than 246 K (melting point inside the pores), there are two different relaxations. The longer component of the relaxation that is of the order of lOx 10" s is divided into three regions. The response in the region T > 267K is due to Maxwell-Wagner polarization. 

The three phase dielectric system backbone-waterlayer-air of a real RF aerogel is reduced to a two layer system. The third phase (air) is neglected because of its relative low influence (compared to the other two phases) on the compound dielectric permittivity according to its own material parameters e and k. In order to explain the measured spectra by Maxwell-Wagner polarization processes due to the absorbed water we propose the following model. ... 

Maxwell-Wagner polarization (20-23) arises in heterogeneous specimens containing domains of different conductivity and/or dielectric constant. This phenomenon can be distinguished by low-frequency impedance dispersions that extend over several decades of frequency. In addition, the magnitude and frequency dependence of Maxwell-Wagner polarization is related to spatial fluctuations of dielectric... 

This is the well-known Maxwell-Wagner polarization. It always arises when two media are in contact and have differing electrical properties. A strong field and a disparity of charges arises at the juncture, leading to the possibility of high effective polarizations. These are ubiquitous in biology. 

Yeo LY, Lastochkin D, Wang S-C, Chang H-C (2004) A new ac electrospray mechanism by Maxwell-Wagner polarization and capillary resonance. Phys Rev Lett 92 133902... 

Fig. 27.1. Wagner polarization experiments, (a) Current is sent from the non-blocking electrode to the blocking electrode. Both ionic and electronic currents can be sustained, (b) Current is sent from the blocking electrode to the non-blocking electrode. There is no electrode reaction to sustain the ionic current, so only an electronic current can be sustained.

Due to the phase-separated structure of immiscible polymer blends including phase boundaries in the corresponding dielectric spectra, MaxweU/Wagner polarization process can be observed especially at low frequencies. As discussed in Sect. 12.2.3.3, the theoretical equations are complex and hard to solve. For certain model systems like inclusion in poly(carbonate filled) with poly(ethylene oxide) (Hayward et al. 1992), it could be shown that for low concentrations the most important quantities are the volume fraction, the geometry of the dispersed phase... 

Interfacial or Maxwell-Wagner polarization is a special mechanism of dielectric polarization caused by charge build-up at the interfaces of different phases, characterized by different permittivities and conductivities. The simplest model is the bilayer dielectric [1,2], (see Fig. 1.) where this mechanism can be described by a simple Debye response (exponential current decay). The effective dielectric parameters (unrelaxed and relaxed permittivities, relaxation time and static conductivity) of the bilayer dielectric are functions of the dielectric parameters and of the relative amount of the constituent phases ... 

Keywords dielectric relaxation, dielectric strength permittivity, dipole moment, polarization, relaxation, conductivity, relaxation time distribution, activation energy, Arrhenius equation, WLF-equation, Maxwell-Wagner polarization. 

The dependence of the ER effect on the dispersed particle conductivity has been comprehensively investigated. As shown earlier, the strongest ER effect was found to occur at the conductivity about 10 S/m for the polyaceneqiiinones/cereclor suspension fllS], and tliere was no detectable ER activity observed once the conductivity shifts far away from this value. A similar result was obtained in oxidized polyacrylonitrilc/siliconc oil suspension and interpreted in view of Maxwell-Wagner polarization [119, 120]. The effect of the particle conductivity on the ER activity was also theoretically analyzed [121-123]. A conduction model was presented for understanding ER phenomena and ER mechanism [124]. The current density of an ER fluid is obviously a very important parameter that scales energy consumption in practical devices. Both the current density and ER activity... 

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