Static electric field

Top PDF Static electric field:

Dynamics of Particle in Confined Harmonic Potential in External Static Electric Field and Strong Laser Field

Dynamics of Particle in Confined Harmonic Potential in External Static Electric Field and Strong Laser Field

Variation of transition probabilities of the bound and free states with respect to the laser frequency  for static electric field E0  0.005 a.u.. for different values of force constant[r]

10 Read more

Static electric field detection and behavioural avoidance in cockroaches

Static electric field detection and behavioural avoidance in cockroaches

Cockroaches approaching a static electric field are subject to considerable electrical forces, clearly illustrated by the antennal deflection observed through high-speed video caused by attraction forces pulling the antennae to the electrode. Before encountering an electric field, the charges on a cockroach are randomly distributed (Fig. 7A). When approaching a positively charged electrode, as used in our experiments, this induces an uneven charge distribution on the cockroach with negative charges attracted towards the electrode and, hence, leading to a passive bending of the antennae towards the electrode by the attraction of opposite charges (Fig. 7B). The imposed deflection of the antennae is detected by sensory receptors leading to a marked bending of the antennae as they are actively withdrawn from the forces attracting them to the electrode. Thus, the cockroaches use their antennae as multi-modal sensors to detect many external cues (Bell and Adiyodi, 1981). Electric fields cause displacement of the antennae about the head–scape joint, deflecting S-HP sensilla. There are three S-HPs on adult cockroach antennae located on the dorsal, medial and lateral surfaces (Staudacher et al., 2005) that detect antennal position in all planes (Okada and Toh, 2001). We have clearly established that it is the displacement of the antennae by electrical forces that are detected by the S-HP mechanoreceptors, enabling an animal to perceive static electric fields. The antennae are known to play a crucial role in insect behaviour and their deflection evokes avoidance or escape movements (Camhi and Johnson, 1999; Comer et al., 2003; Cowan et al., 2006; Okada and Toh, 2006). Information on antennal position is not only provided by the hair plates on the scape but also from pedicel hair plates, from the flagella and from internal movement detectors (Comer et al., 2003; Okada and Toh, 2000; Okada and Toh, 2006; Staudacher et al., 2005). Together, they provide information about deflection of the antennae in all planes of movement (Okada and Toh, 2001; Staudacher et al., 2005).
Show more

9 Read more

Studies on Absorptive Transitions Between Rotational Sublevels of Symmetric-Top Molecules in a Static Electric Field

Studies on Absorptive Transitions Between Rotational Sublevels of Symmetric-Top Molecules in a Static Electric Field

- 27 electri~ field E from the above expression for the line frequency gives for the voltage to be applied to the electrodes The Stark voltage for resonance evidently is independent of f[r]

106 Read more

Accurate Computation of Electric Field Enhancement Factors for Metallic Nanoparticles Using the Discrete Dipole Approximation

Accurate Computation of Electric Field Enhancement Factors for Metallic Nanoparticles Using the Discrete Dipole Approximation

Abstract We model the response of nanoscale Ag prolate spheroids to an external uniform static electric field using simulations based on the discrete dipole approximation, in which the spheroid is represented as a collection of polar- izable subunits. We compare the results of simulations that employ subunit polarizabilities derived from the Clausius– Mossotti relation with those of simulations that employ polarizabilities that include a local environmental correc- tion for subunits near the spheroid’s surface [Rahmani et al. Opt Lett 27: 2118 (2002)]. The simulations that employ corrected polarizabilities give predictions in very good agreement with exact results obtained by solving Laplace’s equation. In contrast, simulations that employ uncorrected Clausius–Mossotti polarizabilities substantially underesti- mate the extent of the electric field ‘‘hot spot’’ near the spheroid’s sharp tip, and give predictions for the field enhancement factor near the tip that are 30 to 50% too small.
Show more

5 Read more

Exposure of laboratory animals to small air ions: a systematic review of biological and behavioral studies

Exposure of laboratory animals to small air ions: a systematic review of biological and behavioral studies

other air molecules. Because of the low concentration and low probability for systemic absorption, a biologically plausible mechanism by which air ions—either positive or neg- ative—could mediate physiological changes or cause either beneficial or adverse effects on health is neither obvious nor claimed to be known. A possible exception may be that at high air ion densities the charge on body hair from air ions and any accompanying static electric field may be perceived by mechanosensory stimulation. Nevertheless, numerous studies reported in the literature have made claims of biologically significant effects. The purpose of this analysis is to comprehensively review the results of animal laboratory studies of air ion exposure. This review updates the assessment presented in the 1997 Oak Ridge National Laboratory report on exposures related to direct-current transmission lines [20]. The findings of this systematic review of animal studies do not support claims that air ions have any biologically significant effects. Recent systematic reviews of the human experimental data on air ion exposure specific to effects on res- piratory function and mood [6, 14] have reached a similar conclusion.
Show more

32 Read more

Nonlinear dielectric relaxation and dynamic Kerr effect in a strong dc electric field suddenly switched on: Exact solutions for the three dimensional rotational diffusion model

Nonlinear dielectric relaxation and dynamic Kerr effect in a strong dc electric field suddenly switched on: Exact solutions for the three dimensional rotational diffusion model

The goal of the present paper is to derive exact analytic equations for the dielectric and Kerr effect response func- tions and relaxation times when a strong static electric field is suddenly applied to an assembly of noninteracting polar and anisotropically polarizable molecules. For this purpose we shall apply an analytical method recently developed for the calculation of the linear response of systems of particles compelled to rotate in three-dimensional space @ 7,10–14 # . The essence of this method is the exact analytical solution of the infinite hierarchy of differential-recurrence relations gov- erning the relaxation dynamics of a Brownian particle in the presence of an external potential by means of ordinary or matrix continued fractions. The method also constitutes a particularly simple way of deriving the hierarchy of linear differential-recurrence relations for desired averages for any particular external potential from the vector nonlinear Euler- Langevin equation for a polar molecule. It is often very dif- ficult to obtain such a hierarchy from the Fokker-Planck equation because of the problems involved in separating the * Author to whom correspondence should be addressed.
Show more

14 Read more

Sub-ionospheric very low frequency perturbations associated with the 12 May 2008 7.9 Wenchuan earthquake

Sub-ionospheric very low frequency perturbations associated with the 12 May 2008 7.9 Wenchuan earthquake

in lower ionospheric conductivity, which is caused by elec- tric field increase before an EQ. The proposed mechanism to explain amplitude enhancement indicates towards chemi- cal channel (quasi-static electric field effect) of lithosphere– atmosphere–ionosphere coupling process (Hayakawa et al., 2010), which suggests that atmospheric electric field gener- ated on or near the ground surface during earthquake prepa- ration can cause significant ionospheric anomalies.

6 Read more

Electromagnetic fields in coupled cavities.

Electromagnetic fields in coupled cavities.

27 Prom Eq. (5*9)> we see that the irrotational electric field does not appear in the expression. It is now- necessary to give the proof_that the exclusion of P<* terms from the general field equations for the sub­ sidiary cavity is justified. Y/e recall that the sur­ face magnetic charge- and current densities over the iris are the only sources of excitation of the sub- sidary cavity, and that there is no electric current or charge present in V. Prom the M axwell’s equation

62 Read more

A Molecular Basis of Olfaction: Odorant-Specific Electric-Field Emission

A Molecular Basis of Olfaction: Odorant-Specific Electric-Field Emission

The electric-field profiles of a variety of chemical agents are shown in Figures 1, 2 and 3. The substances were contained in10 ml glass vials situated 3 meters distant from the sensor. For each test period of data acquisition, the vials were exposed to the sensor for 60 seconds in order to obtain an optimal SigmaPlot signature. The orientation of the plots are shown in a form which permits optimal visual comparisons between substance-specific profiles. Left axis: time, 0-60 seconds; bottom axis: amplitude, maximum 1 mV rms; right axis: frequency range, 280-420 Hz. (We have observed electric field signatures from radioisopes. Current focus is on generation of an algorithm to enable real-time digital identification of chemical substances.) The glass vials can themselves be further enclosed in other structures. The continually
Show more

9 Read more

Experimental Results for Microwave Tomography Imaging Based on FDTD and GA

Experimental Results for Microwave Tomography Imaging Based on FDTD and GA

to the measured data to correct the assumption in modeling and inversion algorithm. This correction coefficient can be obtained by comparing the simulated field values at the observation points for an assumed model with the measured field value from the same model at those receiver points. This correction factor is then applied to the measured scattered field data to compensate for the discrepancy between the measured and simulated field values. In order to calculate this factor, either the incident field or the scattered field of a known reference object has been suggested and used by researchers. Different reference objects such as an empty chamber (incident field) [24], a metallic cylinder [20, 25], nylon, or polyvinyl chloride [26], have been successfully used for different imaging algorithms.
Show more

14 Read more

A theory about induced electric current and heating in plasma

A theory about induced electric current and heating in plasma

MHD is the physical-mathematical framework that concerns the dynamics of magnetic fields in electrically conducting fluids, i.e. in plasmas and liquid metals. One of the most famous scholars associated with MHD was the Swedish physicist Hannes Alfven, who receive the Nobel Prize in Physics in 1970 for fundamental work and discoveries in MHD with fruitful applications in different parts of plasma physics. The notion of frozen-in magnetic field is the result of his work in connection with the discovery of MHD waves [3].

10 Read more

2 ELECTRIC FORCES AND FIELDS

2 ELECTRIC FORCES AND FIELDS

 A CHARGED OBJECT SETS UP AN A CHARGED OBJECT SETS UP AN ELECTRIC FIELD IN THE SPACE. ELECTRIC FIELD IN THE SPACE[r]

48 Read more

Modeling the electric field of weakly electric fish

Modeling the electric field of weakly electric fish

In Fig.·9 we studied the bimodal electric images produced by different-sized objects as a function of lateral distance. We have shown that the fish could, in principle, use the distance between the rostral and caudal peaks of the electric image (delta) in order to unambiguously determine lateral object distance, regardless of object size. The lateral distance measure presented here is different and computationally simpler than the one advanced earlier (von der Emde et al., 1998): only the locations of the two peaks need to be determined by the fish (normalization is not required). The electric fish could subsequently determine the object’s size using the bimodal electric image’s peak-to-peak amplitude (with the reasonable assumption that the object’s conductivity does not change during the electrolocation task). Furthermore, we have seen that measuring lateral object distance from the center of objects (Fig.·9) seemed much more fruitful than measuring it with respect to the object edges (Fig.·10). This corroborates a previous study, which noted that measuring lateral object distance with respect to object center had simpler functional forms (Rasnow, 1996). It seems likely, however, that determining the distance of an object’s edge would be more relevant for the fish. The fish could then, in principle, extract the edge’s distance by using the delta-lateral distance curve associated with the object’s center and then subtract its radius (obtained via the peak-to-peak potential value).
Show more

16 Read more

Schwinger mechanism in electromagnetic field in de Sitter spacetime

Schwinger mechanism in electromagnetic field in de Sitter spacetime

Abstract. We investigate Schwinger scalar pair production in a constant electromagnetic field in de Sitter (dS) spacetime. We obtain the pair production rate, which agrees with the Hawking radiation in the limit of zero electric field in dS. The result describes how a cosmic magnetic field affects the pair production rate. In addition, using a numerical method we study the effect of the magnetic field on the induced current. We find that in the strong electromagnetic field the current has a linear response to the electric and magnetic fields, while in the infrared regime, is inversely proportional to the electric field and leads to infrared hyperconductivity.
Show more

5 Read more

Bioconvective electromagnetic nanofluid transport from a wedge geometry : simulation of smart electro conductive bio nano polymer processing

Bioconvective electromagnetic nanofluid transport from a wedge geometry : simulation of smart electro conductive bio nano polymer processing

16 Validation of this present numerical method has been conducted with existing solutions in the literature. In the absence of electric field parameter (𝐸 𝑓 = 0) , magnetic field parameter (𝑀 = 0), and latent heat transfer of the fluid (𝜆 = 0), thermal conductivity (𝐾 = 1), and no slip boundary condition (𝑎 = 0), the mathematical model defined by Eqns. (17)–(21) with boundary conditions of Eqn. (22) reduces to the case considered by Jafar et al. [45]. Table1shows the comparison for the value of the skin friction function, 𝑓 ′′ (0), with the published Keller box implicit finite difference results of Jafar et al. [45]. Further validation with the earlier quasi-linearization numerical solutions is also included in Table 1. An excellent agreement is found between the present BVP5C computations and the other two solutions. The graphs are drawn for the numerical outcomes and observations are detailed over the effects of the governing parameters on momentum and thermal boundary layers. Figures 2-8 illustrate selected distributions of the key variables i.e. dimensionless velocity, induced magnetic field, temperature, nano-particle volume fraction, and the micro-organism concentration function with transverse coordinate ( 𝜂 ). Figure 9 displays plots for skin friction coefficient, local Nusselt number, local Sherwood number, and local micro-organism transfer rate respectively. These physical quantities must asymptotically approach zero, i.e. 𝑓 ′ (𝜂) − 𝐾 → 0, ℎ ′ (𝜂) − 𝐾 → 0, 𝜃(𝜂) → 0, 𝜑(𝜂) → 0, 𝜒(𝜂) → 0 as 𝜂 → ∞ (for 𝐾 = 1 ),
Show more

36 Read more

ELECTRIC AND MAGNETIC FIELD MANAGEMENT

ELECTRIC AND MAGNETIC FIELD MANAGEMENT

1. EMF Management for Transmission Lines : Among all the sources of EMF, overhead transmission lines produce the greatest EMF. Nowadays, extra high voltage (EHV) is transmitted through overhead transmission lines. The installations and distribution of EHV transmission line produce the highest electric field near the ground surface. Overhead transmission lines (OHTL) produces extremely low frequency (ELF) EMF, which requires reducing to minimum level. In the age of electrification, the evaluation of EHV, people are used to stay around ELF field sources, which may further lead to responsible for biological effects of human as well as living beings. Electric and magnetic field management of overhead transmission lines require different factors such as line designing, Right of way (ROW), shielding, grounding and techniques for reduction of EMF. Electric field is reducing to extremely low values using ground grids of densely spaced wires and the magnetic field of these EHV OHTL can be significantly reduced with voltage upto 115kV or by using loops cancellation method [10].
Show more

8 Read more

Applied Electric Field ZERO

Applied Electric Field ZERO

Electric Properties of Channels, Proteins, as it does Ionic Solutions. Shielding is ignored in traditional treatments of Ion Channels and of Active Sites of proteins[r]

51 Read more

Real Magnetic Poles (Magnetic Charges) in the Physics of Magnetism, Gravitation and Levitation

Real Magnetic Poles (Magnetic Charges) in the Physics of Magnetism, Gravitation and Levitation

1) At first stage happened superficial interpretation of experimental results Oersted when were taken into ac- count only the explicit participants of physical process: the electric current and the magnetic field around the conductor. This interpretation, ignoring the popular wisdom that “the truth never lies on the surface,” took Maxwell, putting it as the basis of their EM theory that more than on one hundred years cemented mistaken view of magnetism as an emanation electricity. And all these years vicious EM-concept of Maxwell remained of the “fulcrum” on which form interpretations of the various magnetic and electromagnetic effects, i.e. in theoret- ical analysis of electric charges dealt solely with complete disregard for the actually existing in the atoms and substance of the magnetic charges.
Show more

10 Read more

Derivation of force constants based on the electric field gradient

Derivation of force constants based on the electric field gradient

From Equation (19), it is proved that the second order force constant is directly derived from electric field gra- dients EFG. Therefore, it is the first time to explore that the force constant is essentially caused by electric field gradients, and the second order force constant and its har- monic oscillator frequency have been derived from elec- tric field gradients. However, the force constants are usu- ally derived from spectroscopic data; however, it is indi- rect with spectroscopic data. Therefore, this is the sup-

5 Read more

Electric field control of magnetization reorientation in Co/Pb (Mg1/3Nb2/3) PbTiO3 heterostructure

Electric field control of magnetization reorientation in Co/Pb (Mg1/3Nb2/3) PbTiO3 heterostructure

Co thin films was deposited on a PMN-PT (011) (thick- ness is 300 μm) substrate by radio frequency magnetron sputtering, as shown in Fig. 1a. The background pres- sure was lower than 5 × 10 -5 Pa. For the deposition of Co layers, a Co target, 75 mm in diameter and 3 mm in thickness was used as the sputtering target, and the argon gas was used as the ambient gas. The sputtering chamber was evacuated to a base pressure 0.2 Pa. The RF power was 50w. The thickness of Co layer was 20 nm. While sputtering, an Ar flow rate of 10 SCCM (SCCM denotes cubic centimeter per minute at STP). Sputtering angle of the film was 20° without applied field. Figure 1b shows the schematic drawing of the sputtering arrangement. The film thickness was mea- sured by the setback instrument (Vecco Dektak 8). The static magnetic properties were measured by vibrating sample magnetometer (VSM) and the dynamic magnetic properties were measured by in-plane ferromagnetic res- onance (FMR) measurements were performed in a JEOL, JES-FA 300 (X-band at 8.969 GHz) spectrometer. The microwave permeability measurements of the films were performed by a vector network analyzer (PNA E8363B) with micro-strip method.
Show more

5 Read more

Show all 10000 documents...