130 results about "Wave mode" patented technology

The present invention provides a method and apparatus for acoustic position logging ahead of a drill bit. The method and apparatus comprise a bottomhole assembly (BHA) conveyed on a drilling tubular in a borehole within an earth formation. The BHA has a source array for emitting preselected acoustic signals into the earth formation, and at least one receiver on the BHA for receiving a second acoustic signal produced by an interaction of the preselected acoustic signal with said formation. The source array for acoustic energy may be configured as an axially distributed array of axially or azimuthally directed sources, or an azimuthally distributed array of axially or azimuthally directed sources. The sources may be activated according to preselected time delays. The emitted acoustic signal is differing in spectrum and/or wave mode from the acoustic energy of a rotating drill string.

Optical plasmon-wave attenuator and modulator structures for controlling the amount of coupling between an guided optical signal and a surface plasmon wave. Optical power coupled to the plasmon wave mode is dissipated in varying amounts producing an intensity modulation effect on the optical signal. For electrical modulation, an additional dielectric (or polymer) layer with variable refractive index in optical contact with a metal layer supporting at least one plasmon wave mode is used to perturb or vary the propagation constant of plasmon wave. Propagation constant variation results in the power coupling variation between the surface plasmon wave and the optical wave. The refractive index variation of the dielectric (or polymer) layer can be accomplished via an electro-optic traveling-wave, a lump-element, or any other integrated optics modulator configuration situated to affect the layer, thereby permitting data rates into tens of GHz. Because of the extremely small interaction lengths needed, the optical plasmon-wave modulator is a very compact device which can be implemented on the top of a fiber or as an integrated optical planar structure.

A touch sensor comprising an acoustic wave transmissive medium having a surface; a plurality of acoustic wave path forming systems, each generating a set of incrementally varying paths through said transmissive medium; and a receiver, receiving signals representing said sets of waves, a portion of each set overlapping temporally or physically by propagating in said transmissive medium along axes which are not orthogonal. The waves may also be of differing wave modes. The receiver system may include a phase, waveform or amplitude sensitive system. Reflective arrays are associated with said medium situated along a path, said path not being a linear segment parallel to a coordinate axis of a substrate in a Cartesian space, a segment parallel to an axial axis or perpendicular to a radial axis of a substrate in a cylindrical space, nor parallel and adjacent to a side of a rectangular region of a small solid angle section of a sphere; situated along a path substantially not corresponding to a desired coordinate axis of a touch position output signal; situated along a path substantially non-parallel to an edge of said medium; has a spacing of elements in said array which differs, over at least one portion thereof, from an integral multiple of a wavelength of an incident acoustic wave; has elements in said array which are non-parallel; has an angle of acceptance of acoustic waves which varies over regions of said array; and/or coherently scatter at least two distinguishable acoustic waves which are received by said receiving system.

A ceiling tile adapted to be supported in an overhead opening and function as a loudspeaker. The tile is in the form of a distributed mode acoustic radiator with a transducer mounted wholly and exclusively on the radiator at a location for coupling to resonant bending wave modes so as to vibrate the radiator and cause it to resonate.

A method for the in vivo non-invasive characterization of the material and architectural properties of a bone in which an ultrasonic wave is introduced into a bone in such way as to produce one or more guided wave modes within the bone, and the signals emerging from the bone are stored and analyzed to determine the propagation characteristics of the guided wave/s. These measured guided wave propagation characteristics are then processed to obtain estimates of desired bone properties such as cortical thickness, bone density and bone elastic constants. The invention also includes an unltrasound arrangement with movable transducers.

The invention discloses a fault positioning method for a transmission line and belongs to the technical field of power systems. The fault positioning method comprises the following steps: arranging a Rogowski coil-based broadband core-through traveling wave detection device on the high-voltage transmission line; acquiring a current traveling wave signal of a three-phase line; performing singular value detection by applying the phase mode conversion and wavelet mode maximum principle; accurately identifying the traveling wave line mode wave head, and accurately determining the wave head arrival time by using a GPS high-precision clock; and measuring the wave speed of real-time traveling wave mode on line according to different wave head time difference information to realize accurate fault positioning. The fault positioning method has the advantages of effectively avoiding two main factors influencing the traveling wave fault positioning precision, along with high positioning precision and accurate and reliable fault positioning result.

The invention relates to a lightning striking fault identifying method of a direct current power transmitting line traveling wave protection. According to the characteristic difference of voltage traveling wave shape between the formed faults and unformed faults, two-pole voltage traveling wave weight and origin direct current weight are used to identify changing trend of the wave shape; ratio of a initial traveling wave mode maximum value and the second mode maximum value is used for representing saltation that the wave shape is cut; combining the two characteristics to achieve the identification of the voltage traveling wave while not causing the faults by lightning pole tower, lightning striking lightning line, lightning striking line shift central distance and the voltage traveling wave of non-lightning short circuit fault by the lightning pole tower, lightning striking line shift central distance. The interference and identification of the two lightning weaves are combined to improve the identifying reliability. A large number of emulations represent that this method is reliable and effective. The physical conception of this invention is intuitionistic and clear and has a rapid action function. The invention does not be influenced by the fault type and transition resistance and it is easy to achieve and suitable for apllying to direct current system protecting device.

A method for the nondestructive inspecting of coated or uncoated pipeline, using ultrasonic guided waves excited on the outer or inner pipe surface, wherein at least one or more transducers are individually or simultaneously excited to generate ultrasound, wherein multiple received signals with different focal spot positions are processed and combined to produce a reduced number of final waveforms that show defect axial positions in the pipe, wherein a data calibration scheme is utilized to adjust velocity variability for all the guided wave modes at different frequencies, and wherein the hardware arrangement has at least one pulser channel and one receiver channel for the collection and storage of signals.

A fiber-optic surface plasmon resonance sensor may include an optical fiber and a surface plasmon excitation layer. The optical fiber may include a core, a cladding surrounding the core, and a depression. The surface plasmon excitation layer may include a first excitation layer, a second excitation layer and an optical waveguide layer between the first excitation layer and the second excitation layer. Incident light incident through the core may be coupled to the surface plasmon excitation layer at a specific angle of incidence and wavelength satisfying the surface plasmon resonance condition. Depending on the polarizing direction of the incident light, an s-polarized component may be coupled to the guided-wave mode in the optical waveguide layer constituting the surface plasmon excitation layer.

In order to design on-chip interconnect structures in a flexible way, a CAD approach is advocated in three dimensions, describing high frequency effects such as current redistribution due to the skin-effect or eddy currents and the occurrence of slow-wave modes. The electromagnetic environment is described by a scalar electric potential and a magnetic vector potential. These potentials are not uniquely defined, and in order to obtain a consistent discretization scheme, a gauge-transformation field is introduced. The displacement current is taken into account to describe current redistribution and a small-signal analysis solution scheme is proposed based upon existing techniques for static fields in semiconductors. In addition methods and apparatus for refining the mesh used for numerical analysis is described.

The invention relates to an impulse vibrating method for testing the bridge substructure natural frequency of vibration which uses avoirdupois weight to stroke the pier and tests the vibrating response of the pier to analyze and compute the natural frequency of vibration. It uses avoirdupois weight to stroke the pier top part and tests the speed and hastens response of the bridge. It usually dose multi-stroke and uses the recording wave mode superposition to dispel the noise to obtain the accurate response wave mode. It reads the response wave mode to do Fourier analysis to ascertain Fourier frequency spectrum and combines with the peak spectrum to ascertain the natural frequency of vibration of bridge.

The invention discloses a plastic waveguide for guiding terahertz (THz) wave with a wavelength ranging from 30 to 3000 μm. The plastic waveguide includes a core and a cladding layer. At least part of the core is made of a first plastic medium having a first refractive index, and the maximum length of a cross-section of the core is smaller than the wavelength of the guided terahertz wave. The cladding layer surrounds the core and has a second refractive index lower than the first refractive index. In the invention, only one wave mode is propagated in the plastic waveguide, and a first attenuation constant of the core for the guided terahertz wave is higher than a second attenuation constant of the cladding layer for the guided terahertz wave.

A sensing method and apparatus using photonic band gap multilayered material. Photonic band gap multi-layers are formed from alternating layers of higher refractive index and lower refractive index materials, and may be deposited or disposed on a optically transparent substrate or a reflecting face of a prism. Light is directed into the prism, directed to the photonic band gap multilayer, and reflected out of the prism, where it is captured and analyzed. Various sensor configurations keep light wavelength or coupling angle fixed, while monitoring the change in the other parameter. Also disclosed is a microarray configuration with an array of probe spots placed on one surface of the multilayer, which is mounted on an x-y translation stage. Also disclosed is a configuration where a cylindrical lens focuses an expanded and collimated light beam to a line that transects the rows of array elements sequentially, producing an image with shifted surface electromagnetic wave modes for each row, corresponding to individual elements of the array row.

A system and method for measuring various weld characteristics is presented. The system and method can comprise a means to measure penetration depth of butt welds in thin plates, for example, using laser generated ultrasounds. Superimposed line sources (SLS) can be used to generate narrowband ultrasounds. A signal processing procedure that combines wavenumber-frequency (k-ω) domain filtering and synthetic phase tuning (SPT) is used to reduce the complexity of Lamb wave signals. The reflection coefficients for different wavelengths corresponding to each wave mode can be calculated. Regression analysis that can include stepwise regression and corrected Akaike's information criterion (AIC) can be performed to build prediction models that use the reflection coefficients as predictors.

The present invention discloses a calculation method for separating symmetric and flexural mode wave packet and extracting weak signal of the bending mode. Based on the wave structure characteristic theory of axisymmetric mode and bending mode, the method uses finite element software to establish correlative model, extracts transient displacement signal of signal acquisition nodes of a guided-wave monitoring surface, and conducts delay superimposing on the collected signals on the frequency domain in accordance with relative formula; then the superimposed frequency domain signal is subjected to the inverse Fourier transform to obtain guided-wave mode wave packet of each order after separation; and Hilbert-Huang envelope is employed to calculate reflection coefficient for each mode. The method uses secondary development function of finite element software to compile the secondary development program, quantitatively analyze the influence degree of the parameters such as characteristics of defect size, location distribution, the number of defects and the center excitation frequency on the amplitude value of the flexural mode reflection echo generated from the defect locations through modal conversion, thereby integrally utilize reflection coefficients of axisymmetric mode and bending mode to evaluate the distribution of defect locations.

A slow wave structure for coupling RF energy with an electron beam comprises a co-propagating RF section including a plurality of pins having a uniform separation from the plane of an electron beam axis. An output aperture is positioned a half wavelength from a reflection section comprising a change in depth of the pintles, such that RF energy reflected by the change in pintle depth is added to the RF energy traveling with the electron beam. One or more rows of pintles are removed in the region of the output aperture to enhance coupling to the output aperture. The device may include a beam shaper for shaping the electron beam to surround the pintles, and the beam shaper and pintles may share common channels which are longitudinal to the electron beam axis. The slow wave structure may operate in forward and backward wave modes, and may be used in conjunction with other structures to form amplifiers and oscillators.

The invention relates to methods, devices, systems and uses of such systems for the generation and detection of electromagnetic fields carrying orbital angular momentum. An electromagnetic wave placed in a resonator having a closed-loop waveguide supporting a guided wave propagating at resonance with angular order, p, and with an angular grating patterned in the closed-loop waveguide, the angular grating having a integer number, q, of grating elements. The angular grating selectively couples the guided wave mode to a free space radiation mode having an OAM quantity, l, and out-of-plane wave vector component, krad,z, and wherein significant coupling to the grating occurs only when the following wave matching condition is satisfied: l=p−mq where: m is the diffraction order of the angular grating, m=1, 2, 3, . . . ,.

The invention relates to a high repetition frequency harmonic wave mode locking fiber laser based on external continuous light injection, comprising a laser pumping source, a wavelength division multiplexing device, an optical isolator, a continuous light source, an optical coupler, a saturable absorber and a gain fiber, wherein the laser pumping source is connected to the pumping input terminal of the wavelength division multiplexing device, and the wavelength division multiplexing device is in connection with the optical isolator, and is then connected to the optical coupler together with the continuous light source; the optical coupler comprises a laser signal output terminal and a signal connection output terminal, wherein the signal connection output terminal is successively in connection with the saturable absorber and the gain fiber; the gain fiber is then in connection with the wavelength division multiplexing device; glowing ions are doped in the fiber core of the gain fiber. The high repetition frequency harmonic wave mode locking fiber laser has the characteristics of simple structure and low cost; through the combination between the continuous light source and a passive mode locking fiber laser, high repetition frequency harmonic wave mode locking is realized; in addition, outputted optical pulses possess the advantages of high repetition rate and narrow pulse width.

The invention relates to a method for judging a D-shaped cable hybrid circuit fault section directing at a strong fault and based on a fault voltage initial row amplitude value comparison, and belongs to the technical field of alternating current transmission line fault location. The method includes the steps that when the strong fault occurs in a D-shaped cable hybrid circuit, fault voltage data in short time windows at the head end before the fault occurs and at the back tail end after the fault occurs are extracted and undergoes phase-mode transformation, so that mode components are obtained; wavelet transform is conducted on the mode components on the two sides, so that a corresponding mode maximum value is obtained; a specific value of a wave mode maximum value of an initial row of the tail end of the fault and a wave mode maximum value of an initial row of the head end of the fault is used as a judgment feature value, and the D-shaped cable hybrid circuit fault section is judged through comparison of the judgment feature value and a preset threshold value. According to the theoretical analysis and a large number of simulations, the method is good in effect.

A method of using ultrasonic guided wave to detect the length of grate column of half buried under different highway roadbed, belongs to nondestructive testing field. The method is to determine parameters of grate column before buried calculate group velocity dispersion curve of grate column before buried; select detection frequency from the curve and input the arbitrary function generator to form a single audio signal through the power amplifier module, switch modules, guided wave transceiver components, stimulate the vertical axisymmetric guided wave mode in the vertical column; the guided wave modal generate end echo when encounter the end of the column, the end echo is sent to oscilloscope through guided wave transceiver components and switch modules, determine the corresponding time of end echo, obtain the group velocity from the group velocity dispersion curve, multiple the group velocity with the echo time, divided by 2 to obtain the length of column. The present invention has the advantages of do not need to consider surrounding medium of column, high detection accuracy and of low cost.