Showing papers on "Electric potential published in 1968"
Patent•
23 Feb 1968
TL;DR: In this article, the authors present an image of the path of the electric field and three chromatic states, the normal color (before the electric potential is applied), the color given off when the electric fields are applied, and the color observed when the field is removed.
Abstract: This disclosure is directed to articles of manufacture, chiefly display devices, containing minute ''''naked'''' droplets or inclusions of cholesteric liquid crystal material in a substantially continuous polymeric matrix, said liquid crystal material changing color or shade of color not only upon application of an electric potential but also upon removal of the field. The image produced has a comparable outline to that of the path of the electric field. Three chromatic states are evident, the normal color (before the electric potential is applied), the color given off when the electric field is applied, and the color observed when the electric field is removed. All three chromatic states are readily discernible from one another. The polymer matrix protects the cholesteric liquid crystal droplets from aging and enhances electric field behavior because the third chromatic state (electric potential removed) has a greater longevity with the matrix-bound material versus unprotected material of identical composition but no polymeric matrix. Other advantages are also discussed.
156 citations
77 citations
01 May 1968
TL;DR: In this article, the electric field and potential distribution in the gap between a cylindrical rod having a hemispherical tip and an infinite plane perpendicular to the cylinder axis were determined using a charge simulation technique.
Abstract: The electric field and potential distribution in the gap between a cylindrical rod having a hemispherical tip and an infinite plane perpendicular to the cylinder axis was determined using a charge simulation technique. This method assumes a charge at the center of the hemisphere and a finite number of semi-infinite axial charges in the cylindrical portion of the rod electrode. Boundary conditions in the cylindrical and spherical portions enabled the formulation of simultaneous equations whose digital solution yielded the assumed lumped charges. The digital computer program provided values of the potential and both field components anywhere in the gap with an accuracy of about 2 percent.
73 citations
62 citations
TL;DR: In this paper, the voltage at the threshold for instability was measured and the frequency of overstability was also measured in a poorly conducting fluid subject to a vertical temperature gradient, and the experimental results support the theory.
Abstract: A uniform vertical electric field produces an instability in a poorly conducting fluid subject to a vertical temperature gradient. A previous paper presents the theory for this instability. Here measurements are made of the voltage at the threshold for instability. Since the instability occurs as an over‐stability, the frequency at the threshold was also measured. These experimental results support the theory. Heat‐transfer measurements show a significant increase in heat flow under the influence of electric fields.
57 citations
56 citations
Patent•
23 Feb 1968
TL;DR: In this paper, an image of a cholesteric liquid crystal with three chromatic states, the normal color before the electric potential, the color given off when the electric field is applied, and the color observed when the field is removed, is presented.
Abstract: This disclosure is directed to articles of manufacture, chiefly display devices, containing encapsulated cholesteric liquid crystals which change color or shade of color not only upon application of an electric potential but also upon removal of the field. The image produced has a comparable outline to that of the path of the electric field. Three chromatic states are evident, the normal color (before the electric potential is applied), the color given off when the electric field is applied, and the color observed when the electric field is removed. All three chromatic states are readily discernible from one another. The encapsulation of the cholesteric liquid crystal provides an unusual advantage regarding electric field behavior because the third chromatic state (electric potential removed) has a much greater longevity with the encapsulated material versus unencapsulated material of identical composition. Other advantages are also discussed.
54 citations
TL;DR: In this paper, the current response of a long GaAs Gunn diode is observed following a step function of voltage applied while a domain is in transit, the excess domain voltage, the apparent charge of one sign stored on the domain, and the peak field in the domain are measured using this technique.
Abstract: The current response of a long GaAs Gunn diode is observed following a step function of voltage applied while a domain is in transit. The excess domain voltage, the apparent charge of one sign stored on the domain, and the peak field in the domain are measured using this technique. These measurements are compared with other results obtained from more direct, high resolution capacitive probe measurements made on oscillating GaAs specimens. Both sets of measurements are compared with the predictions of "invariant domain" calculations. The measured domain voltages are found to be higher than predicted by theory. The differential capacity associated with a domain is about half that predicted by the simple zero diffusion model. Reasons for these results are advanced.
50 citations
TL;DR: In this paper, the authors extended the theory of part 1 to analyse the distribution of velocity and electric current in an electrically conducting liquid between two circular electrodes of finite diameter, when a current is passed between them.
Abstract: In this part we first extend the theory of part 1 to analyse the distribution of velocity and electric current in an electrically conducting liquid between two circular electrodes of finite diameter, when a current is passed between them. The electrodes are set opposite to each other in insulating planes and a magnetic field is applied perpendicular to these planes. When the Hartmann number M [Gt ] 1 we find that the current is confined to the cylinder of fluid joining the electrodes. This effect is accounted for by the velocity which is induced in thin layers of thickness O(M−½), at the circumference of the cylinder. In our analysis we concentrate on these interesting layers and, amongst other results, we find that in the limit M → ∞ the resistance of the fluid between the electrodes becomes that of the cylinder of fluid joining the electrodes.We then describe some experiments to test the validity of this theory. In these experiments we measured, as a function of the magnetic field, (a) the potential difference between the copper electrodes, the fluid being mercury, (b) the electric potential distribution in the fluid between the disks and in the thin layers between the electrode edges, by means of an electric potential probe, and (c) the velocities induced in the layers using a Pilot tube. Our conclusions were: (i) the overall predictions of the theory were correct; (ii) the results of the two probes approximately correlated with each other, despite the theory still having some limitations and the behaviour of these probes still being somewhat uncertain.
39 citations
32 citations
TL;DR: In this paper, the authors derived the transport properties of a dilute gas of polar molecules in the presence of a static homogenous electric field using as a starting point a form of the Waldmann-Snider transport equation.
TL;DR: In this paper, the theory of diffraction of low-energy electrons is formulated along the pseudopotential formalism well known in the theories of metals, and the inner-potential correction is dependent on the incident electron energy without regard to the inelastic processes.
Abstract: The theory of the diffraction of low-energy electrons is formulated along the pseudopotential formalism well known in the theory of metals. A Schroedinger-like equation with the pseudopotential is rewritten as an integral equation which in turn is solved by the t -matrix method of Bennemann. The effects of inelastic processes are expressed in terms of a complex (optical) potential. Inner-potential correction is shown to be dependent on the incident electron energy without regard to the inelastic processes. As an example, the intensity of the 00 wave from the (0001) face of graphite is calculated approximating the potential of each atom by a screened Coulomb potential and the core wave function by a Slater atomic orbital. The orthogonalization of the wave function for the incident electrons to the core wave functions improves the agreement of the calculated result with the observed one by Lander and Morrison.
TL;DR: In this paper, a method is described for predicting the field strength required to produce continuous wave breakdown of gases with spatially varying properties subjected to electric fields of nonuniform intensity.
Abstract: A method is described for predicting the field strength required to produce continuous wave breakdown of gases with spatially varying properties subjected to electric fields of nonuniform intensity. The proposed method is based on a variational principle derived from the electron continuity equation. A Ritz method is used to generate solutions of the variational problem. The approximate solutions are evaluated by comparing them with several exact solutions which are also developed. The use of a one‐term trial function in the Ritz method is found to give very good agreement with the exact solutions. A two‐term approximation provides greater accuracy than is presently available from experimental data.
01 Dec 1968
TL;DR: In this paper, a simplification of the Chapman-Enskog method for the calculation of transport properties of two-temperature, partially ionized gas mixtures in a magnetic field is presented.
Abstract: : A simplification of the Chapman-Enskog method for the calculation of transport properties of two-temperature, partially ionized gas mixtures in a magnetic field is presented. The simplication is achieved by exploiting the fact that the electron mass is much smaller than that of any other constituent of the gas. A systematic study is presented of the tensor coefficients for the electron electrical conductivity, thermal conductivity, and thermal diffusion. The interplay between the degrees of ionization and magnetic field in determining the sign of the transverse electron thermal diffusion coefficient has been examined. Simple formulas for the thermal diffusion coefficients in the presence of magnetic field have been obtained. The unified theory of Kihara and Aono for charged particle interactions was applied to obtain improved values of the transport coefficients when the number of particles in a Debye sphere is not large. These have been compared with theories based on a cut-off Coulomb potential, and on a shielded-Coulomb potential. It was found that the unified theory and the shielded-Coulomb theory are in close agreement. Mixture rules were given for all three transport coefficients, including the case when there is a magnetic field present. Simplifications introduced into the Chapman-Enskog method were also demonstrated in obtaining the transport coefficients of the heavy particles of a three component, two temperature plasma. (Author)
TL;DR: In this article, the effect of positive bias on annealing of radiation damage is obscured by the positive charge induced due to positive bias-temperature treatment alone, and no effect of drain-to-source potential on annesaling has been observed.
Abstract: Radiation damage in p -channel MOS devices by 1.5 MeV electrons has been studied by thermal annealing in conjunction with electric fields between the metallic gate and the substrate. Both positive and negative gate biases retard the process of annealing. Annealing with negative gate bias reveals 1) that during thermal annealing the majority of the electrons that recombine with the positive charge in the oxide originate from the conduction band of the silicon, and 2) that during irradiation a great number of ionized electrons that remain in the oxide do not recombine with the holes, but are trapped in weakly bound states. The effect of positive bias on annealing of radiation damage is obscured by the positive charge induced due to positive bias-temperature treatment alone. No effect of drain-to-source potential on annealing has been observed.
TL;DR: In this paper, the authors investigated the dependence of the electric charge of the edge dislocations in sodium chloride on impurity atoms at room temperature, and found that the edges are negatively charged when the crystal contained positive divalent impurities (Mg ++, Ca ++ ) and are positively charged when it contained negative divalent (S - ).
Abstract: The dependence of the electric charge of the edge dislocations in sodium chloride on impurity atoms was investigated at room temperature. It was found that the edge dislocations are negatively charged when the crystal contains positive divalent impurities (Mg ++ , Ca ++ ) and are positively charged when the crystal contains negative divalent impurity (S - ). Measurements have been done on the decay of the electric potential on the surfaces of the crystal when the crystal is suffering a cyclic plastic bending of 120 c/s of a finite amplitude. The electric potential on the surfaces decays through two stages and the decay depends on the kind and the concentration of the divalent impurity atoms contained in the crystal. This decay aspect was discussed in terms of the dislocation multiplication and the decrease of the electric charge of the dislocations during the cyclic plastic deformation.
TL;DR: In this paper, it is shown that an electric field can make easier the convection origin conditions and that convection is possible if the temperature gradient and the field of gravity are not parallel and in the absence of the second.
TL;DR: In this article, a new derivation of the gravity-induced electric field is given, which is a generalization of the Faraday cage idea, and it is assumed that the force on a test charge surrounded by a conductor is independent of the charge on the conductor and of external electric fields, even when the conductor is differentially compressed by gravity.
TL;DR: In this paper, the breakdown potential of argon flow between flat parallel plate electrodes between flat plate electrodes has been studied in terms of dynamic gas velocity and pressure effects on breakdown potential.
Abstract: Dynamic gas velocity and pressure effects on breakdown potential of argon flow between flat parallel plate electrodes
TL;DR: Resistor networks were developed to measure the magnitude, direction, and location of the resultant dipole moment of isolated hearts or muscles located at the center of a fluid-filled dish, and the resultant location was found to be midway between the centers of the two pieces.
Abstract: Resistor networks were developed to measure the magnitude, direction, and location of the resultant dipole moment of isolated hearts or muscles located at the center of a fluid-filled dish. With the network connected to the dish electrodes, these quantities could be determined from only four bipolar voltage measurements. Energized muscle strips were simulated by dipping pieces of metal of different lengths into the electrolyte. The resultant location was found to be midway between the centers of the two pieces, rather than at the gap between them.
TL;DR: In this paper, Fahleson has observed that for low values of the discharge current the voltage drop across the plasma is proportional to the magnetic field and independent of the current and pressure, while the magnitude of the voltage is generally smaller than the observed value by a factor of 2.
Abstract: In experiments with a homopolar device Fahleson has observed that for low values of the discharge current the voltage drop across the plasma is proportional to the magnetic field and independent of the current and pressure. The rotational velocity corresponds to a kinetic energy for the ions equal to the ionization potential of the gas. These experiments have been analyzed using a steady‐state continuum model of the flow in which the bulk of the gas rotates at a uniform velocity and the current is confined to thin Hartmann boundary layers on the end‐walls. The voltage drop has been calculated as a function of current, pressure, magnetic field, and atomic species. The dependence on these parameters is in good agreement with the measurements under all conditions, while the magnitude of the voltage is generally smaller than the observed value by a factor of 2.
TL;DR: In this paper, the authors investigated the thermo-electric power of hot carriers due to a high electric field E. The experimental results were found to be in a satisfactory agreement with theory and concluded that the energy relaxation for high-energy electrons in n-Ge is determined mainly by acoustical modes.
Abstract: The thermo-electric power of hot carriers UT due to a high electric field E is investigated. Two cases are considered: 1) weak electric field (E ≦ 103 V/cm) and 2) high electric field (E ≧ 103 V/cm). The theory is developed for both cases in the approximation of the isotropic mass and quasi-elastic scattering. Dc pulse measurements on n-type germanium in a weak electric field yield a quadratic dependence of UT on the electric field strength. The experimental results are found to be in a satisfactory agreement with theory. In high electric fields the microwave technique is used. It is concluded that the energy relaxation for high-energy electrons in n-Ge is determined mainly by acoustical modes.
[Russian Text Ignored]
TL;DR: In this article, the authors measured I-V curves and energy loss per cycle in Nb and Nb-Zr superconducting wires and showed that the energy loss is proportional to the number of cycles.
Abstract: AC induced voltages in Nb and Nb-Zr superconducting wires, measuring I-V curves and energy loss per cycle