Showing papers on "Electric potential published in 1982"
TL;DR: An infinitesimal change in electric potential across a polyelectrolyte gel produces a discrete, reversible volume change, which can be several hundred times smaller than that of the swollen gel.
Abstract: An infinitesimal change in electric potential across a polyelectrolyte gel produces a discrete, reversible volume change. The volume of the collapsed gel can be several hundred times smaller than that of the swollen gel.
1,246 citations
TL;DR: In this paper, the shift of the reversible redox potential of small metal particles with size is discussed and the electrochemical properties of these particles are discussed, and the influence of these properties on redox reactions, electrosorption, and chemisorption are discussed.
Abstract: Starting with equations for the shift of the reversible redox potential of small metal particles with size, the electrochemical properties of these particles are discussed. Approximate equations are given for the relationship between the particle size and the surface charge, the potential of zero charge, the surface potential, work function and quantities related to this function. The influence of these properties on redox reactions, electrosorption, and chemisorption are discussed. The results are used to explain experimental observation in connection with the surface enhanced Raman effect. 2 figures, 1 table.
304 citations
TL;DR: In this paper, the force and torque on a charged rigid macromolecule in electric fields were derived based on the Smoluchowski mean field approximation and yields the motion in terms of the electric potential and certain geometric quantities of the particle.
Abstract: General formulas are derived for the force and torque on a charged rigid macromolecule in electric fields. The theory is based on the Smoluchowski mean field approximation and yields the motion in terms of the electric potential and certain geometric quantities of the particle. If convection can be neglected in the ion conservation equations, the theory makes any further hydrodynamic considerations unnecessary. The formulas of Smoluchowski, Huckel, and Henry for electrophoretic mobility are obtained as simple consequences. Smoluchowski’s formula is generalized to nonconstant surface potentials. The torque on an uncharged rod in moderately strong field is considered.
144 citations
TL;DR: This paper presents calculations of the image potential for an ion in an aqueous pore through lipid membrane and the electric field produced in such a pore when a transmembrane potential is applied and develops a projection method that explicitly accounts for this behavior.
87 citations
TL;DR: A method is presented, based upon finite-difference forms of Laplace's equation, for the iterative calculation of three-dimensional electric field distributions in electrically conductive media with emphasis on its use for the prediction of power density in tissue when radio-frequency hyperthermia is utilized in the treatment of cancer.
Abstract: A method is presented, based upon finite‐difference forms of Laplace’s equation, for the iterative calculation of three‐dimensional electric field distributions in electrically conductive media. The method, while generally applicable to any conductive media, will be presented with emphasis on its use for the prediction of power density in tissue when radio‐frequency hyperthermia is utilized in the treatment of cancer. A computer code which performs these calculations has been written in BASIC so that it may be adapted to relatively inexpensive desktop computers for use in treatment planning. Example calculations of the distribution of electric potential, gradient, and power density with specific electrode configurations are presented. Applications and limitations of the technique are discussed.
74 citations
TL;DR: In this article, an improved surface charge method for computation of three-dimensional electric field distribution and its application to optimum insulator design is described, where each curved surface on which the charge is distributed is divided into many curved surface elements instead of planar elements.
Abstract: This paper describes an improved surface charge method for computation of three-dimensional electric field distribution and its application to optimum insulator design. In this method, each curved surface on which the charge is distributed is divided into many curved surface elements instead of planar elements. After computing numerically the charge distribution, the distributions of both potential and electric field are obtained. Because the use of many curved surface elements provides a good approximation of the insulator contour, the correction of insulator contour to achieve optimum insulator design can be performed smoothly.
67 citations
TL;DR: In this article, the global distribution of the electric potential as well as of ionospheric and field-aligned currents on the basis of ground magnetic records are reevaluated, and the results were quite satisfactory indicating that the numerical accuracy of the algorithms is adequate.
Abstract: Recent efforts in estimating the global distribution of the electric potential as well as of ionospheric and field-aligned currents on the basis of ground magnetic records are reevaluated. For this purpose, we have repeated crucial tests for the algorithms by using a data base from the IMS Alaska chain of magnetic observatories along with completely different ionospheric conductivity models. It is found that the ionospheric current patterns are only weakly dependent on the choice of the conductivity, while the calculated field-aligned currents are somewhat more sensitive and the electric field is quite sensitive to the assumed conductivity, as expected. A test is also conducted by using the calculated field-aligned currents as inputs to an inverse calculation to attempt to reproduce the original ground magnetic perturbations. The results were quite satisfactory, indicating that the numerical accuracy of the algorithms is adequate. These tests increase our confidence that ground magnetic records from a close network can be used to study the extent to which the magnetosphere and ionosphere are electrically coupled.
61 citations
60 citations
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20 Sep 1982
TL;DR: In this article, the levels of the electric potentials of a wiring and the image of the distribution of insulating matters by detecting thermal waves excited on the surface of an LSI due to the irradiation of an electron beam and combining the wiring, obtained from a thermal wave signal, with the image obtained from the electrical distribution of the insulating matter and the electrical potentials produced by a secondary electron signal.
Abstract: PURPOSE:To indicate the levels of the electric potentials of a wiring and the image of the distribution of insulating matters by detecting thermal waves excited on the surface of an LSI due to the irradiation of an electron beam and combining the wiring, obtained from a thermal wave signal, with the image of the distribution of the insulating matters and the image of the distribution of electric potentials produced by a secondary electron signal. CONSTITUTION:A sample LSI 1 is periodically driven by an LSI-driving circuit 2 according to data sent from a memory 21. An electron beam discharged from an electron gun 17 is turned into pulses synchronously with the LSI1 by means of a stroboscopic device, then irradiated upon the LSI1. Secondary electrons discharged from the LSI1 are detected by a secondary-electron detector 13, and a secondary electron signal is turned into a binary one by means of the binary circuit of a picture-treating circuit 12. On the other hand, thermal waves excited on the surface of the LSI1 are transferred to an ultrasonic detector 9 in which they are converted into a voltage signal. The thus obtained signal is sent through a sampling circuit 11 to the circuit 12 in which it is turned into a binary one. The circuit 12 treat both of the above binary signals to obtain a ternary image which corresponds to wiring patterns of a low and a high electric potential and insulating matters, thereby enabling three-colored indication for example to be realized on a displayer 14.
60 citations
TL;DR: In this article, a calculation method was proposed for the determination of profiles of stable menisci formed at one end of a capillary raised to an electric potential, where the Laplace equation relative to potential and the pressure balance equation at the liquid surface were solved simultaneously.
TL;DR: The normal component of the dc electric field measured on ISEE-1 ordinarily exhibits an enhancement of a few mV/m over both upstream and downstream values at the earth's bow shock as mentioned in this paper.
Abstract: The normal component of the dc electric field measured on ISEE-1 ordinarily exhibits an enhancement of a few mV/m over both upstream and downstream values at the earth's bow shock. Using the measured relative velocity between the shock and the spacecraft (from the ISEE-1/2 time delay in the magnetometer data), it is possible to transform the observed E enhancement to a potential drop (delta phi). For a subcritical shock the potential drop is found to be very close to the measured change of particle kinetic energy (delta phi, approximately 280 V on day 330, 1977), whereas for a supercritical shock the potential drop is only a fraction of the measured change of kinetic energy (delta phi, approximately 140 V on day 324, 1977).
TL;DR: In this paper, the boundary conditions for the scalar potential and each of the components of the vector potential were determined for a two-dimensional eddy current problem with variable electric conductivity.
Abstract: In calculating eddy currents in a conductor by means of the vector potential for which the Coulomb Gauge is used, the scalar potential appears when the electric conductivity varies in the conductor, while it is not necessary for the case of the constant electric conductivity. As the field equation is a Helmholtz-type equation under the Coulomb Gauge condition, we must determine the boundary conditions for the scalar potential and each of the components of the vector potential. How to determine the boundary conditions is presented, together with an illustrative example of a two-dimensional eddy current problem with the variable electric conductivity.
TL;DR: In this paper, a premidnight auroral arc was observed with high temporal and spatial resolution using the Chatanika incoherent scatter radar and the acceleration was estimated by deconvolving the electron density profiles, differential energy spectra and velocity distriubtions within the arc.
Abstract: Observations of a premidnight auroral arc were made with high temporal and spatial resolution using the Chatanika incoherent scatter radar. The arc was a quiet east-west aligned arc, about 40 km wide, that drifted slowly through the radar beam without appreciably changing in shape or luminosity. The distribution of ionsopheric electric fields and currents associated with the arc were computed from the ion density and line of sight velocity. The electric field was 30 mv/m outside the arc and decreased to a few mv/m within the arc. The horizontal potential drop was only approx.0.6 kV across the arc. By deconvolving the electron density profiles, differential energy spectra and velocity distriubtions were obtained within the arc. From these the accelerating potential parallel to the magnetic field lines was estimated by several techniques. One technique makes use of an empirical relationship between the parallel potential drop and the total electron current. The accelerating potential reached 7 kV at the arc center. The parallel potential drop within the arc is combined with ionospheric electric field measurements to reconstruct the equipotential contours above the arc.
TL;DR: The potential profile of erythrocytes is shown that the potential profile is strongly influenced by the negative charges of phosphatidyl serine at the inner membrane surface.
TL;DR: In this article, a model of a strong, time-independent, and relativistic double layer is studied, where double layers having the electric field parallel to the current are described.
Abstract: A model of a strong, time-independent, and relativistic double layer is studied. Besides double layers having the electric field parallel to the current the model also describes a certain type of oblique double layers. The ‘Langmuir condition’ (ratio of ion current density to electron current density) as well as an expression for the potential drop of the double layer are derived. Furthermore, the distributions of charged particles, electric field, and potential within the double layer are clarified and discussed. It is found that the properties of relativistic double layers differ substantially from the properties of corresponding non-relativistic double layers.
TL;DR: In this article, S3-3 plasma and ac-dc electric field data were used to construct a schematic picture of electrostatic potential structures for an afternoon auroral zone transversal.
Abstract: S3-3 plasma and ac-dc electric field data are used to construct a schematic picture of electrostatic potential structures for an afternoon auroral zone transversal The signatures impressed on the charged particle distribution functions were used to place constraints on the latitude and altitude extent of the structures, while the electric field data provided precise definition of the structures at the satellite altitude Upflowing field-aligned ions, ion conics, accelerated electrons, and the associated ULF-VLF waves are located consistently with respect to the inferred potential structures The potential distribution is found to be V-shaped at high altitudes and S-shaped at low altitudes
TL;DR: In this article, a capacitive divider with an active buffer circuit is incorporated, such that a 50-Ω line can be driven with a 60dB dynamic range and 100MHz bandwidth.
Abstract: It is often desirable, though difficult, to measure electric potential changes within a plasma, including variations due to waves and fluctuations. For a broad range of plasma parameters ac floating potential measurements may be made using the high input impedance probe described in this paper. A capacitive divider with an active buffer circuit is incorporated, such that a 50‐Ω line can be driven with a 60‐dB dynamic range and 100‐MHz bandwidth. Details of the electronic circuit, mechanical construction, and calibration of the probe are given, together with a discussion of the parameter range over which successful measurements may be made.
TL;DR: In this paper, the authors used a low-divergence (100,?rad) KrF laser to trigger 2.8-MV gas switches for lage pulsed-power systems.
Abstract: We are investigating the use of a low-divergence (100, ?rad) KrF laser to trigger 2.8-MV gas switches for lage pulsed-power systems. Using less than 0.1 J of laser energy, we have demonstrated subnanosecond-jitter triggering (1?) of these switches, which are insulated with pure SF6, at voltages between 75-90 percent of the self-breakdown voltage of the switch. The time delay between the laser pulse and the switch closure is relatively insensitive to variations in voltage, with delay changing by as little as 1.5 ns between 80-90 percent of the self-breakdown voltage. We also present parametric studies of laser triggering using lenses with different focal lengths at various input laser energies.
TL;DR: In this paper, the authors used the fact that the net current is zero to derive an expression for the gradient which is free of ambiguities associated with the shape of the averaging volume, one of the shortcomings of the previous theory.
TL;DR: In this article, a new variational wave function to describe the ground state and the excited states of a bound polaron is proposed, which is of the form |Ψ〉 = c|O〉|o n 〉 + ∑ g k ∗ V ∗ ∗ (e i k·r − ρk ∗ )a k + |O ǫ n + O n + o n + |
TL;DR: In this article, a rapidly changing electric field was measured by an optical method using Pockels device, which was successfully applied to the measurement of the electric field with space charge through a simple correction of measured values.
TL;DR: In this article, a technique for determining the latitudinal variation of the electrostatic potential associated with the ionospheric convection electric field is described, based on radar convection velocity experiments, the integral of E• dl is taken northward along the magnetic meridian, starting at low latitudes.
Abstract: A technique is described for determining the latitudinal variation of the electrostatic potential associated with the ionospheric convection electric field. Using the north-south electric field component derived from radar convection velocity experiments, the integral of E• dl is taken northward along the magnetic meridian, starting at low latitudes. The radar data consist of up to 40 independent measurements of plasma convection spanning 15° of invariant latitude centered on Chatanika, Alaska (65°Λ), with half-hour temporal resolution. It has been found that (1) the electric field contributions to the potential at and below 60°Λ are small under most circumstances and (2) the latitudinal variation of the potential is smooth and regular, permiting the potentials to be contoured across local time. It is found from the experiments that the potential often varies uniformly over 10° latitude at dawn and dusk. Electric fields of 50 mV/m are common. It is also noted that the latitude of the greatest negative potential in the premidnight sector coincides with the Harang discontinuity in ionospheric currents. The potentials calculated from the measured plasma drifts exhibit a regular local time variation. Equipotential contours derived from the latitude-local time potential field obtained with the long-duration radar experiments, while not providing a snapshot of the instantaneous pattern, elucidate the large-scale diurnal variation of the electrostatic potential at auroral latitudes. From such contours it is found that a two-cell convection pattern with varying degrees of asymmetry is consistently present at auroral latitudes, that a cross-polar cap potential drop of 70–120 kV is present in moderately disturbed conditions, and that substorms perturb the potential pattern at all local times.
01 Oct 1982
01 Sep 1982
TL;DR: In this paper, the difference of the Coulomb potential for a pointlike and for an extended nucleus is taken as a perturbation of the molecular energy and the observability of the resulting isotope shift in the molecular spectra is discussed in comparison to the usual mass shift.
Abstract: The difference of the Coulomb potential for a pointlike and for an extended nucleus is taken as a perturbation of the molecular energy. Correction terms, which are dependent on the mean square nuclear charge radius, are introduced for the molecular energies. The observability of the resulting isotope shift in the molecular spectra is discussed in comparison to the usual mass shift. Some examples for the pure electronic and rotational energy are presented using high precision laser and microwave experiments on Pb- and Tl-compounds.
TL;DR: Theoretical calculations of the electric potential were carried out using a model of the thylakoid consisting of a spherical dielectric membrane surrounded both inside and outside by highly conductive material as discussed by the authors.
TL;DR: In this paper, a theory for the steady-state potential of insulated surfaces near exposed high voltages is presented, which is bounded below by the zero of the material's I-V curve assuming total suppression of secondary electrons, and above by assuming total extraction of secondaries.
Abstract: A theory is presented for the steady-state potential of insulated surfaces near exposed high voltages. The term 'insulated surfaces' is used to mean either dielectric surfaces or electrically isolated metallic surfaces. The potential is bounded below by the zero of the material's I-V curve assuming total suppression of secondary electrons, and above by assuming total extraction of secondaries. Within these bounds, the material's surface potential is determined consistently with the solution to Poisson's equation external to the vehicle. The theory is compared with rocket experiments and with SCATHA satellite data. Also, an explanation is suggested for the observed 'snapover' of solar cell coverslips from near plasma ground potential to near the potential of positively biased interconnects with increasing bias voltage.
TL;DR: The hypervirial-perturbational method given by the present authors3,4,5,8) is applied to the particle-in-a-box model subjected to an electric field in order to obtain the energy eigenvalues.
Abstract: The hypervirial-perturbational method given by the present authors3,4,5,8) is applied to the particle-in-a-box model subjected to an electric field in order to obtain the energy eigenvalues The corrections up to the fourth-order are calculated in an analytical way, and higher-order corrections are determined by means of a computer Numerical values are compared with previous results