221 results about "Rayleigh wave" patented technology

An active micromixer uses a surface acoustic wave, preferably a Rayleigh wave, propagating on a piezoelectric substrate to induce acoustic streaming in a fluid in a microfluidic channel. The surface acoustic wave can be generated by applying an RF excitation signal to at least one interdigital transducer on the piezoelectric substrate. The active micromixer can rapidly mix quiescent fluids or laminar streams in low Reynolds number flows. The active micromixer has no moving parts (other than the SAW transducer) and is, therefore, more reliable, less damaging to sensitive fluids, and less susceptible to fouling and channel clogging than other types of active and passive micromixers. The active micromixer is adaptable to a wide range of geometries, can be easily fabricated, and can be integrated in a microfluidic system, reducing dead volume. Finally, the active micromixer has on-demand on/off mixing capability and can be operated at low power.

A bond log device comprising a sonde, an acoustic transducer, and an acoustic receiver. The acoustic transducer is comprised of a magnet combined with a coil, where the coil is energizable by an electrical current source. The acoustic transducer can also be comprised of an electromagnetic acoustic device. The acoustic transducer is capable of producing various waveforms, including compressional waves, shear waves, transversely polarized shear waves, Rayleigh waves, Lamb waves, and combinations thereof.

The method and apparatus of the present invention provides for inducing and measuring shear waves within a wellbore casing to facilitate analysis of wellbore casing, cement and formation bonding. An acoustic transducer is provided that is magnetically coupled to the wellbore casing and is comprised of a magnet combined with a coil, where the coil is attached to an electrical current. The acoustic transducer is capable of producing and receiving various waveforms, including compressional waves, shear waves, Rayleigh waves, and Lamb waves as the tool traverses portions of the wellbore casing.

The invention discloses a direct current method for bed-parallel advanced detection of water bearing structure in mine tunnel. Common advanced detection technology comprises a seismic reflection wave method, a Rayleigh wave method and the like, but with the extensive application of a fully-mechanized roadheader, the above methods are harder to adapt to the present production task requirements. The method of the invention is as follows: a mine direct current method seven-electrode series detecting device is used to arrange four current-emitting electrodes of A1, A2, A3 and A4 which are arranged on one straight line near a mine tunnel heading end, and the four current-emitting electrodes respectively form a loop with another current-emitting electrode B arranged at infinity to supply direct current under the ground, so that a direct current field is built; meanwhile, two electrodes M and N with relatively fixed distance behind the tunnel are used for measuring the distribution rule of the electric field; after treatment with special mating interpreting technology, electrical property distribution information in a geologic body 0-140m ahead a drifting tunnel or a tunnel is obtained. The invention has the advantages of small workload, high speed, small possibility of influence by personal factors, high objectivity and high accuracy, and belongs to a non-destructive detection method.

A SAW device includes an IDT which is provided on the principal surface of a quartz crystal substrate having Euler angles (−1.5°≦φ≦1.5°, 117°≦θ≦142°, |ψ|≠90°×n (where n=0, 1, 2, 3)) and excites a Rayleigh wave (wavelength: λ) in a stopband upper end mode. Inter-electrode-finger grooves are recessed between electrode fingers of the IDT. An IDT line occupancy η and an inter-electrode-finger groove depth G satisfy a predetermined relationship in terms of the wavelength λ, such that the SAW device has a frequency-temperature characteristic of a cubic curve having an inflection point between a maximum value and a minimum value in an operation temperature range. The inflection point is adjustable to a desired temperature or a desired temperature range depending on the IDT line occupancy η within an operation temperature range.

An automated scanning system and method, utilizing specialized dual phased array ultrasonic transducers for producing and detecting Rayleigh waves in ceramic bearing balls are provided for nondestructive, non-contact inspection of ceramic bearing balls. The phased array ultrasonic transducer utilizes a complex curvature configuration that enables the dual phased array ultrasonic transducers to focus ultrasonic energy onto the ball to optimally generate and receive Rayleigh wave signals in the spherical objects.

A SAW device has an IDT which is provided in the principal surface of a quartz crystal substrate having Euler angles (−1.5°≦φ≦1.5°, 117°≦θ≦142°, |ψ|≠90°×n (where n=0, 1, 2, 3)) and excites a Rayleigh wave (wavelength: λ) in a stopband upper end mode. Inter-electrode-finger grooves are recessed between the electrode fingers of the IDT. The depth G of the inter-electrode-finger grooves is 0.01λ≦G≦0.07λ, and an electrode finger thickness H and an IDT line occupancy η satisfy a predetermined relationship. Thus, a frequency-temperature characteristic constantly has an inflection point between a maximum value and a minimum value in an operation temperature range, thereby suppressing a fluctuation in an inflection-point temperature due to a manufacturing variation in the IDT line occupancy η.

The invention relates to a safety state fast non-destructive detection method of operation roadbed, the method comprises steps: performing full cover scanning on a detected roadbed by adopting a geology radar to obtain a geology radar image and a dielectric constant of the detected roadbed; detecting Rayleigh velocities VR obtained by each detection point by a wave detector adopting a Rayleigh wave method; performing a penetration detection by a light type power penetrometer to record the hammering numbers N10; obtaining information of a roadbed integral state by analysis and comparison. The invention provides the non-destructive detection method and theoretical system for evaluating the safety state of the operation roadbed, the invention can be widely used for detecting integral states of various roadbeds, has characteristics of wide application range and comprehensive evaluation index; meanwhile, the invention can be applied to the operation roadbed, without damaging the road facilities, the detection construction period can be greatly shortened, and the detection coat can be reduced.

Method and system for ongoing monitoring for underground structure at or near a production wellpad is provided. The system includes a sparse acquisition grid and utilizes information obtained from Rayleigh waves to monitor subsurface structures.

The invention relates to a method of applying Rayleigh waves in non-linear ultrasonic evaluation of surface damage of a metal material. The method comprises the following steps: 1) excitation and reception of Rayleigh waves; 2) detection of reliability of a testing system; 3) measurement of non-linear coefficients when the surface of a test piece has damage of different degrees; 4) repeatable operation of test. Compared to the method of using body waves for ultrasonic nondestructive test, the non-linear ultrasonic evaluation method provided in the invention has the characteristic that Rayleigh surface waves are especially suitable for measurement of non-linear coefficients of large-scale complex plate structures. According to the invention, it is only needed to carry out excitation and measurement of supersonic waves at one side of a structure during measuring, which enables measuring to be simple and easy; the Rayleigh surface waves have advantages favorable for measuring, e.g., concentration of energy on the surface of a structure, a long propagation distance, etc.; operation is simple and easy, so the method is especially suitable for on-site detection of structural elements; effective evaluation of early damage and degeneration of mechanical properties of a material structure can be realized by using the non-linear ultrasonic method.

The invention discloses a sound surface wave integrated magnetic sensor for a magnetic fluid with a back groove type structure, which comprises a piezoelectric substrate, two interdigital transducers (IDT), a magnetic fluid groove and two sets of antennae for receiving and transmitting magnetic wave signals; the two interdigital transducers (IDT) are positioned at two ends of the surface of the substrate respectively; the magnetic fluid groove is arranged in the middle of the bottom of the piezoelectric substrate between the two interdigital transducers; the antennae for receiving and transmitting the magnetic wave signals are connected to omnibus bars of the two IDTs respectively; the sensor can realize passive wireless high-precision real-time magnetic intensity measurement, and receive a radio frequency signal by the antennae, excite a Rayleigh wave (RSAW) on the IDTs; the zero lagging response of the magnetic fluid on the change of an outer magnetic field instantaneously makes the energy of the Rayleigh wave attenuated, converts the attenuated Rayleigh wave into a magnetic wave by the IDTs and transmits the magnetic wave by the antennae. According to the corresponding relation of the changes of the frequency and the amplitude of the transmitted magnetic wave and the magnetic filed intensity change, the magnetic filed change can be accurately measured.

An elastic wave device includes a piezoelectric substrate, an IDT electrode including a first electrode layer which is provided on the piezoelectric substrate and contains Pt as a main component and a second electrode layer which is laminated on the first electrode layer and contains Cu as a main component, and a dielectric film that is provided on the piezoelectric substrate and covers the IDT electrode. The piezoelectric substrate is made of lithium niobate. The dielectric film is made of silicon oxide. The elastic wave device uses Rayleigh waves propagating along the piezoelectric substrate.

An acoustic wave device includes a piezoelectric substrate, a comb-shaped electrode formed on the piezoelectric substrate and configured to excite a Rayleigh wave as a main acoustic wave, a first dielectric film formed above the piezoelectric substrate to cover the comb-shaped electrode, and a second dielectric film having a portion provided between electrode fingers of the comb-shaped electrode and a portion provided above the comb-shaped electrode. The portion provided between the electrode fingers is provided between the piezoelectric substrate and the first dielectric film. The portion provided above the comb-shaped electrode is provided between the comb-shaped electrode and the first dielectric film. A speed of a transverse wave propagating through the first dielectric film is lower than a speed of the Rayleigh wave excited by the comb-shaped electrode. A speed of a transverse wave propagating through the second dielectric film is higher than the speed of Rayleigh wave excited by the comb-shaped electrode.

A nondestructive measuring-method of surface temperature and pressure of cylindrical pressure container includes setting up relation model of Rayleigh wave transition time to pressure container surface temperature and pressure; utilizing measurement unit formed by four Rayleigh wave probe, ultrasonic transceiver circuit, circulation control circuit, time/digit conversion circuit and monolithic computer for calculating out surface pressure and temperature value of pressure container by measuring transition time of Rayleigh wave in transmission distance.

The invention discloses a flexible magnetic field measurement device and a manufacturing method and belongs to the magnetic sensor field. The device comprises a flexible substrate layer, a metal buffer layer, a magnetostrictive layer, a piezoelectric film layer and a protection layer which are sequentially laminated from down to up, wherein a side of the piezoelectric film layer corresponding to the protection layer is provided with an energy transducer layer embedded in the protection layer, and the energy transducer layer is a single-end or double-end resonance type structure composed of aninterdigital energy transducer and a reflecting grating. The measurement device is advantaged in that through utilizing the flexible substrate material, compared with a sensor prepared from a traditional rigidity substrate material, besides surface acoustic wave modes including common rayleigh waves and Love waves, a new wave mode, e.g., lamb waves can be further generated by the flexible magneticsensor, so bending property, high magnetic field sensitivity, integrated processing and low cost are realized, and the measurement device is suitable for miniaturization and intelligentization development of sensors, and the measurement device is applicable to magnetic field measurement and intelligent wearing fields.

The invention discloses a method for detecting early-stage mechanical property degradation of a material by utilizing nolinear rayleigh wave, belonging to the field of nondestructive testing. The invention comprises the following steps: inputting frequency, periodicity and other parameters of a selected transmission signal to a signal generator to generate a required single sound signal, and determining the incident angle theta of the transmission signal according to the wave speed of a piece to be tested; collecting a non-linear Rayleigh wave signal in equal time intervals in the stretching or fatigue loading process of the piece to be tested; and carrying out Fourier transform to obtain basic wave amplitude and secondary harmonic amplitude, computing the ultrasound non-linear coefficient beta, and knowing the early-stage mechanical property degradation of the piece to be tested according to beta. In the invention, a sensor is directly arranged at the edge of the piece to be tested to transmit and receive Rayleigh wave to improve the excitation and receiving efficiencies of the signal and decrease the non-linear influence brought by the coupling of the sensor and the piece to be tested; and both the excitation and the receiving adopt the piezoelectric sensor, thus being more applicable to engineering actual situation, and realizing continuous on-line detection on the piece to be tested.

A surface acoustic wave actuator has a mover arranged on a first surface of a piezoelectric board and comb-shaped electrodes formed on the first surface. High frequencies are applied to the comb-shaped electrodes to generate Rayleigh waves that move the mover. In the surface acoustic wave actuator, the com-shaped electrodes include first to fourth electrodes formed on the first surface of the piezoelectric board, the first and third comb-shaped electrodes being on each side of the mover on an X-axis, the second and fourth comb-shaped electrodes being on each side of the mover on a Y-axis. The mover at least has a permanent magnet. The surface acoustic wave actuator further has a unit to selectively apply a high frequency to at least one of two electrodes one selected from the first and third comb-shaped electrodes and the other from the second and fourth comb-shaped electrodes. The surface acoustic wave actuator also has a mover holder facing the mover with the piezoelectric board interposed therebetween. The mover holder at least has a magnetic material configured to hold the mover.

A surface acoustic wave device utilizing a Rayleigh wave includes a LiNbO₃ substrate having Euler angles of (0°±5°, 0±5°, 0°±10°), an electrode which is disposed on the LiNbO₃ substrate and which includes an IDT electrode primarily including Au, a first silicon oxide film disposed in a region other than the region in which the above-described electrode is disposed, the first silicon oxide film having a film thickness substantially equal to the thickness of the above-described electrode, and a second silicon oxide film arranged to cover the electrode and the first silicon oxide film, wherein the film thickness of the electrode is in the range of about 0.062λ to about 0.14λ, where λ represents the wavelength of a surface acoustic wave, and θ of the above-described Euler angles of (0°±5°, 0±5°, 0°±10°) is in the range satisfying the following Formula (1):

θ=31.72−206.92×exp (−1×T_Au/0.0138)   Formula (1)

where T_Au is a value of Au electrode film thickness normalized with the wavelength λ.

The invention discloses a method for determining mechanical parameters of the stratum via the Rayleigh wave speed. According to the method, information from Rayleigh wave exploration is fully utilized, the mechanical parameters of the stratum in geotechnical engineering are inverted according to the Rayleigh wave speed, comparative verification is carried out by combining drilling data, shearing wave speed and indoor geotechnical test, the different mechanical parameters of the stratum are determined via the Rayleigh wave speed, and reference values of stratum mechanical indexes and stratigraphic division are provided for exploration in geotechnical engineering without drilling and pitting data. The method of the invention is efficient, economical and practical, a lot of drilling and pitting work can be reduced, the method is especially suitable for landform and geologic positions which a drilling machine can hardly reach, a result is reasonable and effectively, the working efficiency is greatly improved, the cost is reduced, and an effective solution is provided to determine the mechanical parameters in geotechnical engineering of the stratum.

The invention relates to a method for dividing bed rock weathering zones by using a longitudinal wave-surface wave speed ratio method. The method comprises the following steps of: (1) arranging an earthquake arrangement graph on the ground surface; (2) carrying out refracted wave inversion on the earthquake arrangement to primarily divide stratums and determine the longitudinal wave speed VP of the stratums; (3) carrying out Rayleigh wave inversion on the earthquake arrangement to primarily divide stratums and determine the Rayleigh wave speed of the stratums to be VR; and (4) dividing weathering zones of rocks according to the formula of VP/VR=K. The method has the advantages that excitation is carried out once, longitudinal waves and surface waves are simultaneously received to achieve the purpose of complex geophysical prospecting, and the cost of seismic exploration can be reduced by more than 60 percent; earthquake arrangement can be flexibly arranged in places which are difficult to carry out geotechnical engineering investigation and drilling, which solves the problem of stratigraphic division; and the K value can be accurately determined through counting a large quantity of pore wave speed testing data and is used as a division standard of rock weathering degrees. The method is an area type prospection method, has the advantage of abundant information by viewing in the grander scheme and has more comprehensiveness compared with drilling.