Potential electric field

Electrical forerunners may be found out as the result of electrical field potential between two points (electrotelluric field on the earth surface) measurement. Usually the background potential is 10 mV and during the earthquake it equals to 70 mV. 

This electrical field potential is measured by means of portable millivoltmeter with high input resistance. The field registration is carried out in the mountain areas at the distance of 5 km and more, at the same time the minimal gradient value is about 10 mV/km. 

When electrons are injected as minority carriers into a -type semiconductor they may diffuse, drift, or disappear. That is, their electrical behavior is determined by diffusion in concentration gradients, drift in electric fields (potential gradients), or disappearance through recombination with majority carrier holes. Thus, the transport behavior of minority carriers can be described by a continuity equation. To derive the p—n junction equation, steady-state is assumed, so that = 0, and a neutral region outside the depletion region is assumed, so that the electric field is zero. Under these circumstances,... 

The electric field potential can be found using Eq. (1). The thermoelectric field intensity can be written as [13] ... 

Fig. 15.27 The use of an electric field potential to capture/repel BG spores and demonstration of the number of bacteria spores captured on the sensor surface. Reprinted from Ref. 22 with permission. 2008 The Royal Society of Chemistry...

Electroosmosis and Its Application for Puri fication of Water. Electroosmosis is the diffusion of a liquid or a gas thru a porous wall or semi-permeable membrane caused by an electric field (potential gradient)... 

Such a photoinduced charge separation can proceed effectively provided an electric field (potential gradient) has been established at the position where the primary photoexcitation takes place. In general, a potential gradient can be produced at the interface between two different substances (or different phases). For example, a very thin (ca. 50 A) lipid membrane separating two aqueous solutions inside the chloroplasts of green plants is believed to play the essential role in the process of photosynthesis, which is the cheapest and perhaps the most successful solar conversion system available. 

Three synthetic approaches to donor-acceptor-substituted conjugated molecules with enhanced orientability in electric fields, potentially applicable to the preparation of electro-optic polymers via electric field poling, are summarized. The three approaches are parallel attachment of chromophores to a common framework, embedding the chromophore in a zwitterion, and head-to-tail oligomerization of chromophores. The oligomerization method as well as the use of dyes as curing agents are briefly discussed in relation to the stability of electric field-induced polar order in polymer matrices. 

UltrasonicVibration Potential (UVP), an electroacoustica] method involving detection of the alternating electric field (potential or current) generated when dispersed species are made to move by imposed sound waves (Figure 4.8). This technique is also referred to as colloid vibration potential (CVP), or colloid vibration current (CVC). 

While the distinction of the electron trajectories as being either direct or indirect and the observation of quantum mechanical interferences among the trajectories can be understood in terms of the DC electric field strength and the photoelectron kinetic energy with respect to the saddlepoint in the Coulomb + DC electric field potential, this is not the only quantity that characterizes the photoelectrons that are emitted. Above the saddlepoint in the Coulomb + DC potential there exists a continuation of the Stark manifold. This Stark manifold manifests itself in the excitation spectrum of the atom, which shows pronounced peaks in the photoionization efficiency as a func-... 

Here, Vtp is the gradient of electric field potential tp in the conductor, which is equal by definition to electric field intensity E. Thus,... 

The technique of hpce, or ce, involves high-vOltage electrophoresis in narrow-bore fused-silica capillary tubes or columns and on-line detectors similar to those used in hplc (p. 123). Components of a mixture injected into one end of the tube migrate along it under the influence of the electric field (potential gradient) at rates determined by their electrophoretic mobilities. On passing... 

The most severe cases of human amnesic shellfish poisoning occurred in males of advanced age, which originally suggested that age and sex are predisposing factors (Perl et al. 1990). However, the age-related predisposition is, at least in part, the result of renal impairment (Teitelbaum et al. 1990) and is supported by several experimental studies (Suzuki and Hierlihy 1993 Truelove and Iverson 1994 Xi et al. 1997). Nonetheless, advanced age may enhance snsceptibihty in other ways to domoic acid. Electric field potential analysis of hippocampal slices determined that aged rats differed from younger rats in that they did not exhibit preconditioned tolerance to domoic acid (Kerr et al. 2002). This was interpreted that the older rats may be deficient in neuroprotective mechanisms. 

Sedimentation or centrifugation potential gradient gravity or centrifugation field particles liquid electric field potential difference per unit of length sed V m" ... 

An electrode interface has a layered structure in which a nonunifomi electric field (potential slope) is generated by polarization of the electrode. An extremely strong electric field of around 10 Vcm in the innermost layer, the so-called electron transfer layer, which is very thin, 10 A or less, might cause a variety of polar effects. Since not only the electron transfer step but also adsorption and some of the chemical steps involved in an electrolytic reaction take place in the electron transfer layer, the electrochemical reaction should be strongly influenced by polar factors. The orientation of polar adsorbed species, such as ions and dipoles, is electrostatically influenced, and consequently the stereochemistry of their reactions is also controlled by this kind of electrostatic factor. 

Magetoresistivity-based sensors, which are based on a resistivity change induced by a magnetic field, have found wide application in industry. However, such sensors are usually fabricated of metals and hence it is difficult to integrate them with conventional semiconductor devices. To develop magetoresistive sensors in semiconductors, one of the key problems is how to effectively inject spin-polarized electrons into paramagnetic semiconductors. The spin Hall effect (SHE), which involves a spin-current transverse to an applied electric field, " potentially provides a new way to resolve this issue. 

References electric field potential at the outer boundary of the Stern layer... 

We use the effective mass approximation. The structure potential is approximated b y a c onsequence o f rectangular quantum barriers a nd wells. Their widths and potentials are randomly varied with the uniform distribution. The sequence of the parameters is calculated by a random number generator. Other parameters, e.g. effective masses of the carriers, are assumed equal in different layers. To simplify the transmission coefficient calculations, we approximate the electric field potential by a step function. The transmission coefficient is calculated using the transfer matrix method [9]. The 1-V curves of the MQW stmctures along the x-axis (growth direction) a re derived from the calculated transmission spectra... 

The fluxes of the two interdiffusing species are equal in magnitude because of the electroneutrality requirement. The more mobil ion is slowed down by electric field potentials, while the slow ion is accelerated. Diffusion is unidirectional and the sample is semi-infinite in the direction parallel to the direction of diffusion. 

The electric field potential is described by Poisson s equation,... 

Fig. 7.10 Distribution of the dimensionless electric field potential in a capillary section for various values of A = Ad/g.

Thus, the task reduces to solving the hydrodynamic and electrodynamic equations vith the appropriate boundary conditions. Omitting the mathematics, ve present the final results for the electric field potential... 

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