Showing papers on "Coupling published in 1972"

Optical power flow in multimode fibers

Abstract: Loss, coupling, and delay differences among the modes of multimode fibers influence their transmission characteristic in a complicated way An approximation of the modes by a continuum leads to a comprehensive description of these interrelations We relate the mode power distribution to the far-field output and calculate these distributions as functions of the fiber length and the input We report measurements of the far-field distributions at various lengths of a cladded low-loss multimode fiber A comparison of theory and experiment yields a quantitative estimate of the mode coupling involved We associate this coupling with random irregularities of the fiber configuration and straightness, and construct a quantitative model of such irregularities

Quick disconnect coupling

Abstract: A quick connect and disconnect coupling for a pair of interfitting male and female coupling members which includes a resilient locking member carried by the male coupling member and snap locking with the female coupling member upon axial engagement of the coupling members into locked condition. Camming means on the female coupling member are engageable with the locking member when the coupling members are further axially engaged beyond the locked condition to contract the locking member into unlocked condition. Upon still further axial engagement of the coupling members, locking member capture means on the male coupling member engage with the locking member to hold the same in contracted condition whereby the coupling members may be separated. Removable stop means may be included between the coupling members to prevent inadvertent unlocking, which stop means must be removed before disconnection of the coupling is possible.

Orientational Dependance of Vicinal and Geminal 13C–1H Coupling

Abstract: The effect of changes in the relative orientation of vicinal and geminal 13C and 1H nuclei, and in the disposition of adjacent substituents, on coupling between these nuclei has been examined with a variety of 13C-labelled carbohydrates. Compounds synthesized for this purpose include derivatives of D-glucose-1- and -6-13C and L-idose-6-13C, and related lactones, and the measurements have been made with p.m.r. spectra of these compounds. Vicinal 13C-1H coupling, both through C—C and C—O bonds shows an orientational dependance analogous to that for protons: i.e., dihedral angles of 60–100° are associated with smaller coupling (0–3 Hz) than angles of 140–180° (4.5–5.5 Hz); sp2 carbon produces splittings of almost twice these values. The observed spacing is smaller when an oxygen atom is in the plane of the coupling pathway than when out of plane, both for vicinal and geminal 13C–1H interactions, and the presence of an extra oxygen also may have a notable impact on the geminal interaction. A study of rotation...

Electric and Magnetic Coupling through Small Apertures in Shield Walls of Any Thickness

Abstract: A method is presented for evaluating the coupling between two identical resonant cavities coupled by a small aperture in a plane common wall of arbitrary thickness. The coupling is related to the frequencies of the symmetric and asymmetric modes of oscillation of the coupled cavity structure, and a variational technique is used to determine those frequencies. The method is applied to circular and rectangular apertures, and it is shown that the coupling is separable into electric and magnetic terms. The results enable theoretical solutions to be obtained for the electric and magnetic polarizabilities of circular and rectangular apertures in walls of zero thickness, and equivalent polarizabilities to be obtained when the wall thickness is nonzero. Curves of numerical values are given for circular and rectangular apertures. With zero wall thickness, the results obtained are the same as those of Bethe for a circular aperture and give good agreement with Cohn's experimental results for rectangular apertures.

Nuclear magnetic resonance spectroscopy. Carbon-carbon coupling.

Abstract: One-bond, carbon-carbon coupling constants have been observed for several series of compounds containing ^(13)C in its natural abundance of 1.1% at both sites. The small (10-15 Hz) coupling constants in cyclopropanes show that the carbon-carbon bonds have low s character. Substituent and hybridization effects on the carbon-carbon coupling of aliphatic and alicyclic alcohols, ketones, and five- and six-membered aromatic heterocycles have been observed. Carbon-carbon couplings in methyl derivatives are proportional to carbon-proton coupling in similar bonding situations, with a slope similar to that predicted and observed by Karabatsos for the correlation of carbon-proton and proton-proton couplings. Two- and three-bond carbon-carbon coupling constants are interpreted in terms of the Fermi contact mechanism by correlations with proton-proton and carbon-proton coupling constants in similar bonding situations.

Torque limiting coupling

Abstract: A torque limiting coupling having a driving member and a driven member and which limits the amount of torque transmitted between the members. When excessive torque is attempted to be transmitted, the coupling is released and over-runs freely until the coupling is reset by causing reversal of its relative direction of rotation. The coupling utilizes a plurality of balls which act between pockets in the two opposing members, thereby causing axial separation and release of the coupling when one of the members rotationally moves relative to the other.

Pulse propagation in multimode dielectric waveguides

Abstract: Using coupled power equations to describe the average performance of a multimode waveguide with random coupling, it is shown that a Gaussian input pulse remains approximately Gaussian with a pulse width that increases proportionally to the square root of the length of the waveguide. The proportionality factor is determined for the model of a slab waveguide. Since coupling between guided modes of necessity causes coupling of some of the guided modes to radiation modes, radiation losses are un-avoidable. A desired improvement in pulse distortion that is accomplished by coupling the guided modes intentionally to each other must be paid for by a certain loss penalty. This loss penalty is also evaluated for the special case of the slab waveguide model. Pulse dispersion improvement can be achieved by providing intentional roughness of the core-cladding interface of the dielectric waveguide. The “power spectrum” of the core-cladding interface function must be designed very carefully in order to minimize the radiation loss penalty that accompanies any attempt to reduce pulse dispersion. The dependence of the loss penalty on the shape of the “power spectrum” of the core-cladding interface function is studied in this paper. Design criteria for the improvement of multimode pulse dispersion are given based on the slab waveguide model. The connection between the slab waveguide model and the round optical fiber is pointed out.

Self-Consistent Electron-Phonon Coupling in the Tight-Binding Approximation. II

Abstract: The validity of the rigid-atom model for electron-phonon coupling in the tight-binding approximation is examined within the linearized self-consistent theory. It is shown that the deformation-induced charge-density wave will generally reduce the strength of the coupling, thus reducing the Kohn anomaly in the phonon spectrum and the superconducting transition temperature computed from the rigid-atom model. The charge-density wave does not appear for certain modes; the optimal situation is that of the (nearly) half-filled band, when the rigid-atom model gives approximately correct results.

Mutual coupling in phased arrays of randomly spaced antennas

Abstract: Mutual coupling effects in phased arrays with randomly located elements are studied. The network formulation of antenna arrays is found to be a convenient and useful approximation. Two main effects of coupling are separately considered. The first is the increase in the sidelobe level. A new solution for the distribution of sidelobe level has been obtained which is applicable even for small arrays. It is found that the increase in sidelobe level is noticeable only for small average spacing (e.g., less than 2.5 wavelengths). The second effect of coupling is that it causes the fluctuation of main-beam amplitude as a function of the scan angle. The probabilistic properties of these fluctuations are studied. In the uniformly spaced arrays the accumulation of coupling effects may cause "blind angles". In random arrays this accumulation is highly improbable. This method of removing blind angles is further illustrated by an experiment on diffraction gratings where Wood's anomalies and blind angles are recognized as identical phenomena. Finally, an important contribution of this investigation is the analysis by various methods of the radiation pattern of random array. The results obtained by these methods agree remarkably well with the Monte Carlo simulations.

Hollow dielectric waveguide for distributed feedback lasers

Abstract: Hollow dielectric waveguides with gas-filled core and a dielectric tube seem promising as laser structures. The tube fulfills the dual role of a guidance structure for the electromagnetic radiation as well as that of a container for the plasma of the gas laser. Feedback for laser oscillation is achieved by providing coupling between forward- and backward-traveling modes by means of periodic ripples of the inner surface of the hollow dielectric tube. This paper is devoted to the derivation of the coupling coefficients between two guided modes that are coupled by ripples in the tube wall. The calculation is based on the model of a slab waveguide. Expressions for the leaky-mode losses and the scattering losses inevitably introduced by the coupling mechanism are also presented.

Plane-wave theory of parametric oscillator and coupled oscillator-upconverter

Abstract: Previous steady-state plane-wave theory for the singly resonant parametric oscillator has been extended to the case of arbitrary mirror reflectivities using the exact solutions given by Armstrong et al. [3] for the parametric interaction of three traveling waves. Numerical results are obtained for the efficiency, pump power transmission, optimum output coupling, threshold for the second mode, etc., for parametric oscillators with arbitrary mirror reflectivities and operating under arbitrary power levels. The analysis is also applied to the intracavity-coupled parametric oscillator-upconverter.

Light coupling data transfer system

Abstract: A system especially for use in accurately transmitting patient derived data comprising a light coupling unit employed for patient isolation purposes, a modulating unit for generating a constant amplitude switching waveform of a frequency higher than the patient derived data having zero crossings which are modulated thereby to drive the light coupling unit between an on and off state, and a demodulating unit connected from the light coupling unit for demodulating the zero crossing information derived to essentially recover the patient derived data.

On the Coupling Scheme in Uranyl Complexes

Abstract: Simple theoretical considerations of the ligand field type have been applied to the electronic structure of insular uranyl complexes. The study of the consequences of equatorial ligation is used as a means to test the applicability of different coupling schemes for the isolated uranyl ion. From the analysis of the spectra of a large number of different uranyl complexes of Dnh symmetry, it was previously shown how the effect of equatorial ligation consists in lifting certain degeneracies of the free uranyl electronic energy levels and introducing variations in the corresponding transition probabilities. In this note the equatorial field operator is successively applied to uranyl wavefunctions derived in a Russell‐Saunders approximation, in an ω ‐ω coupling approximation, and in an intermediate scheme. Only Russell‐Saunders coupling allows a satisfactory explanation of the observed splitting and intensity pattern.

Mutual coupling effects in semi-infinite arrays

Abstract: An analysis of mutual coupling effects in linear and planar uniformly spaced semi-infinite arrays is presented. The currents under arbitrary excitations at the array ports are obtained by solving an infinite order difference equation with the aid of an extension of the Wiener-Hopf factorization procedure to finite Fourier transforms. The solution for mutual coupling coefficients as well as for the active reflection coefficients in a phased semi-infinite array is expressed explicitly in terms of the active impedance in a phased infinite array. The analytical results are directly applicable to the evaluation of "edge effects" in large phased arrays. Numerical results for active reflection coefficients and element patterns are presented for a semi-infinite array of slots in a perfectly conducting ground plane and for a linear dipole array.

Theory of Three‐Dimensional Reactive Collisions Using Natural Collision Coordinates

Abstract: Starting from the classical kinetic energy expressed in natural collision coordinates, the Hamiltonian operator is derived for three dimensional reactions of the form AB+C→near linear intermediate→ A + BC. After writing the wavefunction as a sum of products of symmetric top wavefunctions (which provide for orientation of the plane of the three particles) times internal functions (which determine the size and shape of the three particle triangle), a system of coupled equations is obtained for the internal functions. Coupling mixes states of different K (component of angular momentum along rotating z axis). At large distances, K± 1 coupling is important even though the bending potential vanishes. At small distances, K ± 2 coupling is most important but even this should be small for a near linear intermediate. After expanding the internal functions in a perturbed stationary state basis, coupled differential equations (containing only local potentials) are obtained for the translational functions. The rotatio...

Shaft-coupling device preventable from over-torque transmission

Abstract: A mechanical shaft-coupling device fitted with at least one steel ball, inserted at the coupling part of driving and driven shafts, engages with both the driving and driven shafts under normal load to transmit normal torque but, shifts its position to cut the transmission with the driven shaft in over-loaded condition so that the driving shaft idles and no over-torque works on the driven shaft.

Personnel protection sleeve

Abstract: A sleeve of predetermined length that fits over one end portion of a high pressure flexible hose assembly. One end of the sleeve is coupled to or near a coupling of the hose assembly while the opposite end of the sleeve is unfastened.

Flexible disc coupling for tandem coupling assembly

Abstract: A flexible disc-type coupling for use in a tandem coupling assembly transmits torque through a plurality of flexible discs. Each of these discs has a flexing area which includes at least one, but not more than about four, circumferentially extending convolutions. The discs are held apart by incompressible spacers and the area between the convolutions is free from all solids so that contact between flexure points, and thus surface damage, is avoided.

Power tool with torque control

Abstract: The drawings illustrate a power tool whose torque output may be continuously measured and controlled by the torque reaction on a rotatably mounted planetary ring gear, with transducer means associated therewith for converting the torque reaction to a fluid pressure signal to cut off the fluid flow to the motor rotor at a predetermined torque.

Upper limit of the torque of the solar wind on the Earth

Abstract: An upper limit is presented for the torque exerted on the earth by the solar wind. It is found that the maximum possible torque is 3 or 4 orders of magnitude too small to be responsible for the slowing of the earth's rotation, contrary to Coleman's (1971) suggestion.

Reaction Zone‐Shock Front Coupling in Detonations

Abstract: Some new observations are reported of the delayed effect of chemical reaction on the trajectory of an isolated triple point in a detonation. The implications of these observations relative to the self‐sustenance of finite amplitude transverse waves on a propagating detonation front are developed. A new criterion for the minimum size of a detonation cell is found, based on the requirement that a reaction‐generated compression wave must overtake the triple point within the first half of the cell. This feature and certain other acoustic wave propagation phenomena are incorporated in a new, qualitatively quite detailed model of a detonation cell.

Coupling for connecting the adjacent ends of shafts

Abstract: A flexible coupling for connecting the adjacent ends of shafts, comprising hubs adapted to be non-rotatably fixed to the adjacent ends of the shafts, said hubs providing radially spaced concentric bearing members, containing peripherally spaced, longitudinally extending opposed grooves within which are mounted roller bearings and walls at the end of the bearing members for retaining said roller bearings in the grooves and the inner bearing member within the outer bearing member, said grooves being of uniform cross-section from end-to-end and said roller bearings being shorter than the distance between the walls and tapering from a maximum diameter at their midlengths toward their ends.