Showing papers on "Transverse plane published in 1990"

Overview of transverse effects in nonlinear-optical systems

Abstract: Beams of light interacting with nonlinear-optical materials naturally form complex transverse profiles. Self-focusing, filamentation, modulational instabilities, spontaneous pattern formation and symmetry breaking, nonlinear waveguiding, and transverse mode excitation are but some of the many phenomena that are observed in lasers, in optical bistability, and in the free interaction of beams. As an introduction to a special issue of the Journal of the Optical Society of America B on transverse effects in nonlinear-optical systems, we provide this overview of history and current work.

Measurement of the Transverse Mechanical Properties of High-performance Fibres

Abstract: The measurement of the transverse modulus of single fibres having a diameter of 5–15 μm has become possible by the development of a new instrument. An account is given in this paper of an investigation of some typical high-performance fibres for their transverse modulus and their fibre strength in transverse compression. The high-performance fibres studied were aramid fibres having different longitudinal moduli, pitch and PAN carbon fibres, also of different modulus values, and some other reference fibres. These fibres had strong anisotropy in the longitudinal and transverse directions to the fibre axis, and there was correlation between the two directional moduli. The transverse strength by the two directional moduli. The transverse strength by compression was also investigated for these fibres. Organic fibres of highly oriented polymers showed a ductile property in transverse compression and had a yielding stress, but carbon and ceramic fibres showed brittle behaviour in compression. A correlation betwe...

Quantum oscillations in the transverse voltage of a channel in the nonlinear transport regime.

Abstract: A transverse voltage is observed when a current is passed through a narrow channel in a twodimensional electron gas, using two nonidentical opposite point contacts äs voltage probes. The transverse voltage is even in the applied current, and exhibits oscillations äs the number of occupied subbands in one of the voltage probes is varied. The effect is shown to be related to the thermopower of a quantum point contact.

Source inversion of the 1988 Upland, California, earthquake: Determination of a fault plane for a small event

Abstract: We examined short-period P waves to investigate if waveform data could be used to determine which of two nodal planes was the actual fault plane for a small ( M L 4.6) earthquake near Upland, California. We removed path and site complications by choosing a small aftershock ( M L 2.7) as an empirical Green function. The main shock P waves were deconvolved by using the empirical Green function to produce simple far-field displacement pulses. We used a least-squares method to invert these pulses for the slip distribution on a finite fault. Both nodal planes (strike 125°, dip 85° and strike 221°, dip 40°) of the first-motion focal mechanism were tested at various rupture velocities. The southwest trending fault plane consistently gave better fitting solutions than the southeast-trending plane. We determined a moment of 4.2 × 10 22 dyne-cm. The rupture velocity, and thus the source area could not be well resolved, but if we assume a reasonable rupture velocity of 0.87 times the shear wave velocity, we obtain a source area of 0.97 km 2 and a stress drop of 38 bars. Choice of a southwest-trending fault plane is consistent with the trend of the nearby portion of the Transverse Ranges frontal fault zone and indicates left-lateral motion. This method provides a way to determine the fault plane for small earthquakes that have no surface rupture and no obvious trend in aftershock locations.

Directional differences in excitability and margin of safety for propagation in sheep ventricular epicardial muscle.

Abstract: Computer simulations and isolated tissue experiments were used to characterize the relation between excitability and margin of safety for propagation in anisotropic ventricular myocardium. Longitudinal, uniform transverse, and nonuniform transverse tissue directions were modeled in a one-dimensional Beeler-Reuter based cable. Stimulation threshold was smallest in the nonuniform transverse direction. The safety factor for propagation was determined in the model as the total axial charge that was available for depolarizing downstream tissue divided by the threshold charge that was just sufficient for continued propagation and was largest in the longitudinal direction. The strength-interval plot for the junction between simulated longitudinal and nonuniform transverse directions identified a range of stimulus strengths and intervals that resulted in nonuniform transverse but not longitudinal propagation. When high values of transverse resistance were used, higher stimulus strengths during premature stimulation resulted in longitudinal but not nonuniform transverse propagation. The experimental strength interval plots from 17 L-shaped preparations of isolated sheep epicardial muscles had similar characteristics. In nine additional L-shaped tissue experiments, changing extracellular K+ concentrations from 4 to 20 mM resulted in progressive membrane depolarization and conduction impairment in both directions. However, in eight of nine experiments, complete block occurred first in the transverse direction. In one experiment, block was simultaneous in both directions. We conclude that, under normal conditions, threshold requirements for active propagation are lower for transverse than for longitudinal propagation. In addition, when active membrane properties are impaired, the safety factor for propagation is larger in the direction along the longitudinal axis of the cells.

Apparatus for monitoring the motion components of the spine

Abstract: An apparatus is disclosed for monitoring the functional motion characteristics of the spine in each of three planes. The apparatus is designed to be mounted on the back of a patient and it includes an exoskeleton of T-shaped elements which resemble the spinous process and the transverse process of the spine. The elements each include a central bore for receiving a cable, and three separate openings for receiving a wire therethrough. The cable is attached to a potentiometer which measures twisting movement of the spine, and each of the three wires is attached to a separate potentiometer so as to measure flexing in the and sagittal and transverse planes. The signals from the potentiometers are processed so as to provide, for each of the three planes, a measurement of the angular position of the spine as a function of time, the angular velocity as a function of time, and the angular acceleration as a function of time.

Scattering from a cavity-backed slit in a ground plane-TM case

Abstract: Two-dimensional transverse electric wave scattering from a cavity-backed slit in a ground plane is analyzed by R.F. Harrington and J.R. Mautz's (1976) generalized network formulation. The admittance matrix of the cavity or arbitrary shape and medium is obtained by the finite-element method. A variational equation for the cavity problem is established and then discretized to a matrix equation. An efficient algorithm using the modified frontal-solution algorithm is developed to solve the matrix equation. The solution is manipulated to get the admittance matrix of the cavity. The computed admittance matrix is added to the radiation admittance matrix of the equivalent magnetic current on a ground plane and is used to solve for the equivalent magnetic current on the slit. Numerical results for trapezoidal and coated rectangular cavities are included. >

Direct measurement of the transverse velocity of dark spatial solitons

Abstract: We describe the direct experimental measurement of the transverse propagation velocities of dark spatial solitons. Good agreement is obtained from a comparison of the velocities measured experimentally and the velocities predicted by the two-dimensional theory of Zakharov and Shabat [Sov. Phys. JETP 37, 823 (1973)].

Search for Collective Transverse Flow Using Particle Transverse Momentum Spectra in Relativistic Heavy Ion Collisions

Abstract: The particle transverse momentum spectra recently measured in relativistic heavy-ion collisions at CERN and BNL are analysed within an expanding fireball model. All the particle spectra at a given beam energy can be reproduced simultaneously with a single set of intensive parameters for the initial state of the fireball. As typical freeze-out parameters in this beam energy region we find a freeze-out temperatureTf≃110 MeV for most hadrons, and an average transverse expansion velocity at freeze-out of 〈v/c〉≃0.4–0.45. The striking enhancement at transverse momentapT<200 MeV/c in the CERN pion data cannot be fully explained by the existence of transverse flow.

TE scattering by an inhomogeneously filled aperture in a thick conducting plane

Abstract: The electromagnetic characterization of the transmission and scattering properties of an aperture in a thick conducting plane filled with an inhomogenous composite material for transverse electric polarization is discussed. Of particular interest in this analysis is the introduction of a new technique that combines the finite element and boundary integral methods. To allow the treatment of large apertures, the conjugate gradient method (CGM) and fast Fourier transform (FFT) are also incorporated for the solution of the resulting system. Numerical examples that demonstrate the validity, versatility, and capability of the technique are presented. >

Coupling means between a light source and a bundle of optical fibers and method of making such coupling means

Abstract: This coupling means comprises a sleeve containing a bore in which is located a bundle of optical fibers, at least some of which are of compression-deformable material. The input ends of the fibers, which receive light from a light source, are located in a predetermined plane. The bore tapers from a relatively large diameter at a location in a second plane spaced from said predetermined plane to a relatively small diameter at said predetermined plane. The tapered bore is of such a size that the optical fibers therein are laterally compressed and the compression-deformable fibers are so deformed in transverse cross-section relative to their normal cross-sections that the fibers more completely fill the bore in its relatively small diameter region than in said second plane.

Transverse discharge excited laser head with three electrodes

Abstract: A new configuration of the electrodes of a transverse discharge pumped gas laser is disclosed, in which the electrode connected to ground (1) and the electrode connected to the main condenser bank (3) are placed on the same plane so as to face a third electrode (2) connected to a high impedance. There are two distinct discharge regions, one of which is the back path of the current passing through the first discharge region.

Mode coupling in circular-cylindrical system and its application to fingerprint resonators

Abstract: Coupled-mode equations are given in the circular-cylindrical coordinate system for the evaluation of two-dimensional fingerprint resonators. The general form of coupled-mode equations is outlined. The coupling coefficients are found for transverse electric and transverse magnetic modes. The quality value Q is defined, and a numerical evaluation is given. A detailed derivation of the coupled-mode equations is given. >

Rotary cutting apparatus

Abstract: The apparatus comprises, between each pair of upper and lower bearing blocks, a shim or strut which provides a support for two bearing blocks on one another. Each of the upper bearing blocks is extended, in an upper portion and toward an inside of said apparatus, by a cantilevered portion subjected to action, in a downward direction, of a pressure exerting vertical jack mounted in an upper portion of said apparatus. A vertical and transverse plane containing a central axis of each pressure exerting vertical jack is situated between a vertical and transverse plane in which is situated a shim or strut placed between the bearing blocks and a vertical and transverse plane of raceways for an upper cutting cylinder and a lower cutting cylinder.

Conservation of complex power technique for waveguide junctions with finite wall conductivity

Abstract: Scattering at the junction of two waveguides with finite wall conductivity is rigorously treated using E-field mode matching and the conservation of complex power technique. At the transverse junction discontinuity between the two waveguides, the complex power absorbed by the junction wall is taken into account along with the usual transfer of complex power from one guide to the other. This leads to a generalized form of the scattering matrix (S) of the lossy junction which incorporates the surface impedance Z/sub m/ of the transverse metallic wall, assumed to be a good conductor. The specific case of a copper transverse diaphragm with centered circular iris in an X-band guide is considered and the equivalent TE/sub 10/ shunt admittance is computed. Numerical results are also given for lossy X-band cavity resonators with circular coupling holes. >

Explicit crack problem solutions of unidirectional composites - Elastic stress concentrations

Abstract: This paper examines the stress concentration problems in unidirectional continuous fiber composites due to transverse multifilament failure. The loading conditions are considered: uniform load at infinity and concentrated force dipole on the crack plane. The boundary value problems are formulated based upon a two-dimensional elastic shear-lag model. The present theory is unique in that the general solution for the multifilament failure problem is obtained explicitly using the Legendre polynomials and that the stress concentration factors in all fibers on the crack plane are given in closed forms. The present analysis also provides rigorous proofs of Hedgepeth's inspection on the tensile stress concentration factor and Fichter's inspection on the shear stress concentration factor at the tip of a notch. b d EA Fn G ^nm h

Methods and apparatus for the continuous formation of an extruded product

Abstract: IMPROVEMENTS IN OR RELATING TO METHODS AND APPARATUS FOR THE CONTINUOUS FORMATION OF AN EXTRUDED PRODUCT Method and apparatus for the continuous formation of an extruded product from material containing fibres, molecules or other constituents susceptible to alignment or other ordered orientation. While the extrudate is still molten and moving through the die, in the direction of the extrusion axis, it is subjected to pulsating displacements in a direction transverse relative to that axis. These displacements give rise to a shearing action within the material, resulting in a degree of transverse orientation of the constituents. This orientation may be "locked" in to the extruded product when the melt solidifies, so improving the transverse strength of that product, and/or may correct an unwanted orientation that existed in the melt upstream of the point where the pulsating displacements were applied. The displacements may be applied by the synchronized operation of pistons, operating in chambers which open into the die cavity at separated locations all lying in the same transverse plane. The extrusion of products of rectangular, tubular and other sections is described, as are various methods of applying forced cooling to the die to accelerate the solidification of the molten product.

Surface Plasmon-polaritons on an Anisotropic Substrate

Abstract: The case of a surface plasmon-polariton (excited by transverse magnetic light) propagating at the interface between an isotropic metal (silver) and an anisotropic (uniaxial) substrate is considered. The field distribution within the system is illustrated when the optic axis of the substrate is not orthogonal in the plane of light propagation. It is seen that in this case a component of the electric field perpendicular to the plane of propagation exists, and in certain circumstances this can become a propagating transverse electric mode. Thus a transverse electric re-radiation occurs, which is enhanced by the surface plasmon resonance, this could form the basis of an electro-optic switch using the anisotropic properties of a liquid crystal layer.

Optical cable with at least one optical waveguide

Abstract: The optical waveguide (AD) has a substantially rectangular internal opening in the form of a chamber (CA) for accepting the optical fibers arranged in the form of ribbon conductors (BL1-BLn). The optical fibers (AD) (sic) has a preferred bending plane (BP), the ribbon conductors being arranged with their broad sides substantially parallel to this preferred bending plane (BP), and the ribbon conductors (BL1-BLn) being guided in an undulating fashion such that their excursion extends transverse to the preferred bending plane.