66 results about "Resonance frequency shift" patented technology

A non-contact wireless communication apparatus and a mobile terminal apparatus are provided. The non-contact wireless communication apparatus includes a non-contact wireless communication antenna, a resonance capacitor, connected in parallel with the non-contact wireless communication antenna, for obtaining a predetermined resonance frequency with the non-contact wireless communication antenna, a resonance frequency adjustment unit for changing a resonance capacitance of the resonance capacitor to adjust the resonance frequency, a capacitance change amount control unit for controlling a change in resonance capacitance of the resonance capacitor in the resonance frequency adjustment unit, a resonance frequency shift unit for shifting the resonance frequency of the non-contact wireless communication antenna, and on / off control unit for performing on / off control of the resonance frequency shift unit in accordance with the amount of change in resonance capacitance of the resonance capacitor by the capacitance variation control unit.

The invention provides a sensor for monitoring an environmental parameter in concrete comprising an enclosure for embedding in concrete; a detecting means connected to the enclosure for detecting at least one environmental parameter in concrete, the detecting means comprising at least one capacitive element for measuring capacitive change; an active material connected to the enclosure, the active material being liable to respond to the environmental parameter and the active material being operably connected to the capacitive element; a RFID chip mounted within the enclosure, the RFID chip being operably connected to the detecting means; and an antenna operably connected to the RFID chip, the antenna being operably connected to the detecting means, and the antenna being part of an L-R-C circuit whose resonance frequency shifts within an assigned frequency band. The invention also provides a MEMS-based capacitor that responds to an environmental parameter in concrete.

A vibration wave driven apparatus capable of preventing a resonance frequency of a vibrator from being shifted to a frequency side higher than a fixed drive frequency of the vibrator during the execution of phase difference control or voltage control. Driving signals are supplied from a control apparatus to a vibration-type actuator having a piezoelectric element that functions as an electromechanical energy conversion element. To control the drive of the vibration-type actuator, either a phase difference between the driving signals or a voltage of the driving signals is changed. When either the phase difference or the driving signal voltage is changed, the frequency of the driving signals is set to a predetermined frequency higher than the frequency for use when neither the phase difference nor the driving signal voltage is changed.

A Push-Pull-type electrostatic ultrasonic transducer includes a first electrode having a through hole, a second electrode having a through hole making a pair with the through hole of the first electrode, and a vibration film held between a pair of electrodes composed of the first and the second electrodes and having a conductive layer to which a direct-current bias voltage is applied, and holds the pair of electrodes and the vibration film. Assuming that λ is the wavelength of the carrier wave having a frequency shifted as a predetermined amount of frequency from the resonance frequency, which is the mechanical resonance frequency of the vibration film, the thickness t of each of the pair of electrodes is set to (λ / 4)·n or roughly (λ / 4)·n (where, λ is the wavelength of the ultrasonic wave, n is a positive odd number), and an alternating-current signal, which is a modulated wave obtained by modulating the carrier wave in the ultrasonic frequency band with a signal wave in an audible frequency band, is applied between the pair of electrodes.

A method for measuring a material's complex permittivity is provided where a near-field microwave probe is positioned a predetermined distance from a first and a second standard sample for measuring a relative resonant frequency shift of the near-field microwave probe for standard samples. Based on measurements, calibration coefficients are calculated. A relative resonant frequency shift of the near-field microwave probe for a sample under study is measured by fast frequency sweep technique while the distance between the tip of the probe and the sample under the study is maintained nominally at the distance between the tip of the probe and each standard sample during a calibration procedure by a shear-force based distance control mechanism. Also, the change in the quality factor of the probe for unloaded and loaded resonator is measured. The dielectric constant of the sample under study is calculated using the resonant frequency shift and the change in the quality factor of the near-field microwave probe for the sample under study and the calibration coefficients obtained during the calibration procedure.

Method for measuring a target particle property. A suspended microchannel resonator is calibrated to determine the relationship between a detected mass and a resonance frequency shift of the resonator. The target particle is suspended in a fluid and introduced into the resonator, and the resonator frequency shift due to the particle is measured. Target particle mass is calculated from the resonator frequency shift, the target particle density, and the fluid density. A target particle property such as size or volume is determined from the calculated target particle mass.

A measurement technique based on a microwave near-field scanning probe is developed for non-contact measurement of dielectric constant of low-k films. The technique is non-destructive, non-invasive and can be used on both porous and non-porous dielectrics. The technique is based on measurement of resonant frequency shift of the near-field microwave resonator for a plurality of calibration samples vs. distance between the probe tip and the sample to construct a calibration curve. Probe resonance frequency shift measured for the sample under study vs. tip-sample separation is fitted into the calibration curve to extract the dielectric constant of the sample under study. The calibration permits obtaining a linear calibration curve in order to simplify the extraction of the dielectric constant of the sample under study.

A grammage measuring apparatus including a dielectric resonator which is arranged only at one side surface of a sample; a shielding container with which the dielectric resonator is substantially covered except for a sample measuring surface; a microwave excitation device which causes the dielectric resonator to generate an electric field vector; a detection device which detects transmission energy or reflection energy by the dielectric resonator; a storage device in which a calibration curve indicating a resonance frequency shift amount for a grammage is stored; and a data processing device which calculates the grammage of a measuring sample from the calibration curve and measurement result of the resonance frequency shift amount of the measuring sample.

A measurement technique based on a microwave near-field scanning probe is developed for non-contact measurement of dielectric constant of low-k films. The technique is non-destructive, non-invasive and can be used on both porous and non-porous dielectrics. The technique is based on measurement of resonant frequency shift of the near-field microwave resonator for a plurality of calibration samples vs. distance between the probe tip and the sample to construct a calibration curve. Probe resonance frequency shift measured for the sample under study vs. tip-sample separation is fitted into the calibration curve to extract the dielectric constant of the sample under study. The calibration permits obtaining a linear calibration curve in order to simplify the extraction of the dielectric constant of the sample under study.

Multi-energy radiation sources comprising charged particle accelerators driven by power generators providing different RF powers to the accelerator, capable of interlaced operation, are disclosed. Automatic frequency control techniques are provided to match the frequency of RF power provided to the accelerator with the accelerator resonance frequency. In one example where the power generator is a mechanically tunable magnetron, an automatic frequency controller is provided to match the frequency of RF power pulses at one power to the accelerator resonance frequency when those RF power pulses are provided, and the magnetron is operated such that frequency shift in the magnetron at the other power at least partially matches the resonance frequency shift in the accelerator when those RF power pulses are provided. In other examples, when the power generator is a klystron or electrically tunable magnetron, separate automatic frequency controllers are provided for each RF power pulse. Methods and systems are disclosed.

Method for measuring a target particle property. A suspended microchannel resonator is calibrated to determine the relationship between a detected mass and a resonance frequency shift of the resonator. The target particle is suspended in a fluid and introduced into the resonator, and the resonator frequency shift due to the particle is measured. Target particle mass is calculated from the resonator frequency shift, the target particle density, and the fluid density. A target particle property such as size or volume is determined from the calculated target particle mass.

A Push-Pull-type electrostatic ultrasonic transducer includes a first electrode having a through hole, a second electrode having a through hole making a pair with the through hole of the first electrode, and a vibration film held between a pair of electrodes composed of the first and the second electrodes and having a conductive layer to which a direct-current bias voltage is applied, and holds the pair of electrodes and the vibration film. Assuming that λ is the wavelength of the carrier wave having a frequency shifted as a predetermined amount of frequency from the resonance frequency, which is the mechanical resonance frequency of the vibration film, the thickness t of each of the pair of electrodes is set to (λ / 4)·n or roughly (λ / 4)·n (where, λ is the wavelength of the ultrasonic wave, n is a positive odd number), and an alternating-current signal, which is a modulated wave obtained by modulating the carrier wave in the ultrasonic frequency band with a signal wave in an audible frequency band, is applied between the pair of electrodes.

The invention discloses a method for detecting shock-absorption and noise-reduction performance of a car damping material. The method comprises detection on two aspects, i.e. the detection of a damping material on the aspect of the feeling of passengers for the vibration noise in the process of simulating the real driving process, and the detection of the damping material on the aspect of reducing the vibration of the overall structure of a car body and the bias of resonant frequency. By adopting a novel method for detecting the shock-absorption and noise-reduction performance of the damping material which is reasonably combined with the car body of a specific car, the shock-absorption performance index of the damping material applied to the car can be simply and intuitively expressed, the complicated modeling work can be omitted, the detection work is relatively simplified, the result is intuitive and dependable, and the application prospect is remarkable.

A vibration wave driven apparatus capable of preventing a resonance frequency of a vibrator from being shifted to a frequency side higher than a fixed drive frequency of the vibrator during the execution of phase difference control or voltage control. Driving signals are supplied from a control apparatus to a vibration-type actuator having a piezoelectric element that functions as an electro-mechanical energy conversion element. To control the drive of the vibration-type actuator, either a phase difference between the driving signals or a voltage of the driving signals is changed. When either the phase difference or the driving signal voltage is changed, the frequency of the driving signals is set to a predetermined frequency higher than the frequency for use when neither the phase difference nor the driving signal voltage is changed.

The invention relates to a concrete beam prestress value and prestress loss monitoring method. The method includes extracting resonant frequency and root-mean-square deviation from piezoelectric admittance signals of piezoelectric ceramic of the prestress concrete beam to recognize prestress value of a prestress concrete beam and extracting resonant frequency deviation indexes and root-mean-square deviation indexes to recognize prestress loss of the prestress concrete beam. The method provides a new way for real-time monitoring of the prestress value and the prestress loss of the prestress concrete. Compared with the prior art, the method can achieve quick monitoring, can obtain the prestress value and the prestress loss quickly of the prestress concrete beam not provided with a sensor for measuring the prestress value, and can accurately evaluate the loading force of the prestress concrete beam in the normal use state.

A resonance frequency shift amount Δf and a peak level change amount ΔP are measured using a microwave resonator, V1 and V2 are obtained based on V1=(Δf·∈″2 / Kf−ΔP·∈′2 / Kp) / (∈′1·∈″2−∈″1·∈′2), and V2=(Δf·∈″1 / Kf−ΔP·∈′1 / Kp) / (∈″1·∈′2−∈′1·∈″2), and an absolute dry basis weight and a moisture amount are obtained based on absolute dry basis weight=β·V1, and moisture amount=γ·V2. For the constants Kf, Kp, c′1, ∈′2, ∈″1 and ∈″2, the constants ∈′1, ∈′2, ∈″1 and ∈″2 are determined so that the variance values of Kf and Kp are smaller than a predetermined value.

The invention provides a method and system for achieving vehicle wireless charging through resonance-frequency shift. By the adoption of the method and system, wireless high-power vehicle charging with the power ranging from about 5 kW to about 150 kW is achieved, and constant-current voltage-limited charging management is completed. The system comprises a non-vehicle-end variable frequency emitting device and a power receiving device installed on an electric vehicle. According to the method and system for achieving vehicle wireless charging through resonance-frequency shift, frequency-shifted electric energy is emitted from a power emitting disk through two resonance circuits in a wireless mode, the electric energy is received by a power receiving disk, after rectification, a battery pack of the electric vehicle is charged, the requirement of the charging instruction of a battery management system BMS is met, in other words, the output power of the power emitting end and the output power of the power receiving end are controlled in a frequency shifted mode, and then constant-current voltage-limited charging is achieved. By the adoption of the mode that NFC and Bluetooth communication are combined, the electric vehicle can accurately establish the unique wireless communication channel link with a charging pile or a charger of the parking stall of the electric vehicle, the electric vehicles in a parking lot are in communication with the charging piles or the chargers in the parking lot in a one-to-one mode, link interference is avoided, and a stable negative feedback wireless control circuit is provided.