69 results about "Force frequency" patented technology

Techniques are provided for use in controlling rate-adaptive pacing within implantable medical devices such as pacemakers or implantable cardioverter-defibrillators (ICDs). In one example, a force-frequency relationship is determined for the heart of the patient, which is representative of the relationship between cardiac stimulation frequency and myocardial contractile force. To this end, various parameters are detected for use as surrogates for contractile force, including selected systolic pressure parameters and cardiogenic impedance parameters. Rate-adaptive pacing is then controlled based on the detected force-frequency relationship to, for example, deactivate rate-adaptive pacing if the slope and/or abscissa of the force-frequency relationship indicates significant contractility dysfunction within the patient. In other examples, rather than deactivating rate-adaptive pacing, control parameters are adjusted to render the rate-adaptive pacing less aggressive. In still other examples, trends in the slope and/or abscissa of the force-frequency relationship are monitored to detect contractility dysfunction and/or heart failure and titrate medications accordingly.

Acoustic sensing utilizing a cantilever structure coupled about at least one side of said cantilever to a base substrate, wherein said cantilever includes a piezoelectric section and has at least one acoustic wave device on a portion of the cantilever, wherein a flexure of the cantilever produces force-frequency effects measurable by the acoustic wave device. According to one embodiment, the cantilever sensor uses the flexure-frequency effect as measured by an acoustic wave device to sense a target matter. According to one embodiment, a sensing material is disposed on at least a portion of at least one surface of the cantilever.

Machine vibration baselines are synthesized without averaging historical vibration data. Instead machinery configuration information is used, including data about the machine train, the machine's rotating components, and the machine speeds. For each component being considered, a plurality of parameters is identified for deriving baseline portions. The parameters for one component are used to identify baseline vibration amplitude floor values, vibration amplitudes at frequencies corresponding to various harmonics of a rotational speed, and vibration amplitudes corresponding to forcing frequencies and their harmonics/sidebands. Parameters for other components also may be used to identify amplitudes at harmonic frequencies and forcing frequencies.

The invention discloses a positive and negative stiffness parallel-connection low-frequency vibration isolation device of a coupling dynamic vibration absorber. A cam-ball-spring mechanism symmetry arrangement is taken as a negative stiffness mechanism, the negative stiffness mechanism is in parallel connection with a positive stiffness spring to form a quasi-zero stiffness vibration isolator, andon this basis, a dynamic vibration absorber is additionally arranged to form a positive and negative stiffness parallel-connection vibration isolation system of a coupling linear vibration absorber;based on the anti-resonance characteristic in a multi-degree-of-freedom system, the additional dynamic vibration absorber is used for absorbing the vibration energy of a main system, so that the vibration energy is transferred to the dynamic vibration absorber to weaken the vibration intensity of a main structure; when the exciting force frequency is close to the inherent frequency of the dynamicvibration absorber, the power provided by the dynamic vibration absorber to the main system gradually offsets the exciting force acting on the main system, so that the amplitude of the main system canbe reduced sharply; and the vibration absorber with proper quality, stiffness and damping is selected, so that the force transmission rate curve can be moved leftwards, the initial vibration isolation frequency is reduced, the vibration isolation frequency bandwidth is expanded, and the low-frequency vibration isolation performance of the system is improved. The vibration isolation device has high static stiffness and low dynamic stiffness, has wide vibration isolation bandwidth and can be popularized and applied to low-frequency vibration control.

A method for dynamic investigation of a subject lung, the method comprising the steps of: (i) imparting an oscillation to the lung at one or more forcing frequencies so as to elicit a lung response, (ii) sensing the response of the lung simultaneously with the imparting of the oscillation to elicit a lung response, (iii) choosing at least one parameter used in the sensing to define the lung motion associated with the lung response, (iv) comparing one of the chosen parameters at each forcing frequency with the response at the forcing frequency in at least one region of the lung, and (v) recording the comparison of step (iv).

The invention relates to the field of kinetic energy power generation of electric automobiles, in particular to a method. According to the method, when a spring upper automobile body with a vertical elastic system vibrates in the running process of an electric automobile, a spur rack vertically fixed in the spring upper automobile body is meshed with a gear which is arranged on another elastic vibrating body and in which a unidirectional bearing is sleeved, the elastic vibrating body is unidirectionally and synchronously driven to be subjected to forced frequency resonance or effective vibration to generate kinetic energy, and a kinetic energy power generation device arranged on the elastic vibrating body generates power by using the generated kinetic energy.

The invention discloses a micro-vibration signal processing method for processing acquired micro-vibration signals and obtaining disturbance-vibration force and error analysis. The micro-vibration signal processing method comprises the following steps of: firstly, installing a calibration disc on a six-component eight-sensor disturbance-vibration-force testing platform fixedly, hammering 16 calibration points on the calibration disc by using a standard force hammer, and when hammering at every time, acquiring voltage time-domain signals of the force hammer and eight sensors and a frequency response function of the six-component disturbance-vibration force testing platform; obtaining a calibration matrix and calibration errors by the calibration process; secondly, acquiring time-domain data by a data acquisition system when moving parts on the six-component eight-sensor disturbance-vibration-force testing platform generate small disturbance for the testing platform, acquiring the time-domain data by the data acquisition system, obtaining a frequency-domain result by fast Fourier transform, obtaining a disturbance-vibration-force frequency-domain signal by the calibration matrix and obtaining disturbance-vibration-force time-domain data by inverse Fourier transform.

The invention discloses a self-adaptive torsional vibration damper. The self-adaptive torsional vibration damper comprises an inner shell, an outer shell and resonators arranged between the inner shell and the outer shell; each resonator comprises a mass block and a restraint spring, each mass block is supported between the inner shell and the outer shell through the corresponding restraint spring, and the resonators are arranged in pairs and are symmetrically distributed around the center of a rotating shaft; and when the excitation force frequency and the resonance frequency of the rotatingshaft are coincident, the resonators conduct targeted absorption on torsional vibration energy under the frequency to reduce vibration, the torsional vibration amplitude value can be reduced from thesource angle, and safe operation of a shafting system is ensured.

The invention relates to a tactile stimulating device with measurable tactile stimulating force and adjustable force frequency. The tactile stimulating device comprises an alternating current motor mechanism which is used for sending a pulse and driving an eccentric wheel to rotate, an elastic steel ruler mechanism for generating elastic deformation, an eccentric wheel mechanism for generating force data, and a probe mechanism which is used for generating a displacement in the vertical direction to change to stimulate the epidermis of a living organism, wherein the alternating current motor mechanism is fixedly connected with the eccentric wheel mechanism; the eccentric wheel of the eccentric wheel mechanism is closely attached to an elastic steel ruler of the elastic steel ruler mechanism; and the probe mechanism is fixedly arranged on the lower end surface of the elastic steel ruler mechanism. The tactile stimulating device is simple in structural design, high in integration degree and safe to work; an electromagnetic material covers the outer surface of an alternating current motor to form an electromagnetic shielding device, so that interference is basically eliminated, and the signal stability is high; by the adoption of a noninvasive mechanical stimulation mode, no wound can be caused in the use process; and as the frequency can be adjusted and the stimulating strength can be adjusted, the force action is stable, and the tactile stimulation within a relatively wide frequency range can be flexibly modulated.

Radio frequency (RF) power is sent out by a base station to radio frequency identification transponders (RFID tags) for a first time at a first frequency. The frequency is changed to a second frequency, and the RF power sent out for a second time substantially different from the fist time so as to tend to improve data throughput. In one embodiment forced frequency “hops” are implemented if the time it takes to perform a particular transaction is greater than the time available on a particular carrier frequency. In one embodiment, a radio frequency identification (RFID) base station processor (in conjunction with program information stored in a base station memory) is adapted to (i) determine the amount of time available on a particular carrier frequency (e.g., pursuant to Federal Communications Commission (FCC) regulations, European Telecommunications Standardization Institute (ETSI) regulations, etc.), (ii) determine the amount of time it would take to perform a particular transaction, and (iii) force the base station to “hop” to another carrier frequency if the transaction time is longer than the available time. In one embodiment, the time it would take to perform a particular transaction is the time it would take to perform the next transaction. In another embodiment, the time it would take to perform a particular transaction is the time it would take to perform the longest (or “worst-case”) transaction. In alternate embodiments, a transaction is defined as the transmission of information (e.g., data, commands, etc.) or both the transmission of information and the reception of related information.

The invention discloses a Duffing oscillator detection method for a chirp signal under a strong noise background. The method is characterized by comprising the following steps: intercepting and demodulating a chirp signal; carrying out quantitative determination on the phase state of a Duffing oscillator based on a Poincare mapping feature function; and carrying out frequency conversion Duffing oscillator detection of a chirp signal. When the method is used for detection, the built-in driving force frequency of the Duffing oscillator system is changed and thus a single-frequency signal component in the demodulated frequency signal is scanned; and whether the system has a resonance phenomenon is determined based on the Poincare mapping feature function value outputted by the detection system, so that the chirp signal detection under a low-signal-to-noise-ratio background is realized. The method has advantages of good scientific and reasonable properties, high applicability and good effect.

A method for estimating a steady state response of a drill string in a borehole includes calculating a first displacement of the drill string in a frequency domain for a first excitation force frequency and a number of multiples of this frequency using an equation of motion of the drill string. The equation of motion has a static force component, an excitation force component, and a non-linear force component with respect to at least one of a deflection and a derivative of the deflection of the drill string. The method further includes: transforming the first displacement from the frequency domain into a time domain; calculating a non-linear force in the time domain; calculating a frequency domain coefficient derived from the calculated non-linear force in the time domain; and calculating a second displacement of the drill string in the frequency domain using the equation of motion and the frequency domain coefficient.

The invention relates to a monitoring control system for rail transportation, comprising at least one sensor group arranged at a selected monitoring point of a rail. Each sensor group comprises at least one acting force sensor and one vibration sensor; a rail dynamic signal processing circuit is connected with the sensor group and used for respectively receiving and converting an acting force time-domain signal measured by the acting force sensor of the sensor group and a vibration time-domain signal measured by the vibration sensor, and sending the converted signals to a signal calculating and processing unit; the signal calculating and processing unit comprises an acting force signal time-domain/frequency-domain conversion circuit, a vibration signal time-domain/frequency-domain conversion circuit and a frequency responding function calculating unit, wherein the frequency responding function calculating unit divides a received acting force frequency-domain signal and a received vibration frequency-domain signal to generate an input and output response spectrum signal, therefore, the abnormal status of the rail can be judged according to the input and output response spectrum signal.

The invention discloses a wind turbine blade made from a shape memory fiber hybrid composite material and a manufacturing method of the wind turbine blade, and aims to solve the technical problem of dither caused to an existing fan blade by instability of wind. The wind turbine blade is characterized in that the fan blade adopts the shape memory fiber hybrid composite material as a driving material; the rigidity of shape memory fibers is changed by controlling the value of the current in order to change the rigidity of the shape memory fiber hybrid composite material, so that variable-rigidity control on the blade material is realized, the inherent frequency of the blade is far away from an excitation force frequency range, and fan damages caused by dither of the blade can be avoided. By adopting the shape memory fiber hybrid composite material, the wind turbine blade disclosed by the invention has the advantages of being remarkably reduced in vibration in comparison with the wind turbine blade made from a glass fiber reinforced composite material in the background technology, also realizing semi-active control of the blade, solving the problem of dither of the wind turbine blade and being lower in cost in comparison with the wind turbine blade made from a carbon fiber composite material.

The invention discloses a cable force testing method based on the support stiffness of an unknown damper under a complicated boundary condition. A technical problem that the cable force-frequency relationships of the inhaul cables change greatly because of installation of various dampers at end portions of inhaul cables of the modern bridges and thus the precision of cable force measurement by theconventional frequency method is affected can be solved. According to the invention, a finite-element cable force testing method for damper identification is provided for the inhaul cable with a damper. An inhaul cable is established and the position of a rubber ring of the damper is replaced by a spring device equivalently; a cable force frequency relationship under support stiffness of different dampers is obtained; the support stiffness of the inhaul cable is identified by using multi-order practically measured frequency and the cable force-frequency relationship is corrected; and then onthe basis of an interpolation principle, a practically measured cable force is determined by the practically measured frequency. When the cable force testing method is applied to a certain arch bridge, the finite-element-method-based cable force-frequency relationships before and after installation of the dampers at the end portions of the cable are close to the field practically measured results,so that the certain engineering value is verified.

The invention relates to a long-term automatic cable force monitoring system based on a vibration method. The system comprises a vibration sensor, a knocking device for knocking an inhaul cable, a vibration collector and a control platform; the vibration sensor is connected with the vibration collector; the control platform is connected with the vibration collector and the knocking device; and the control platform controls collection time of the vibration collector and controls work of the knocking device. The system can test the practical cable force in a better way by means of excitation of a reliable outside force, and the problem that the cable force frequency cannot be excited by the wind speed at present is solved.

Particulate matter is dispersed in a fluid material. A sample including a first material in a fluid state and second material comprising particulate matter are placed into a chamber. The second material is spatially dispersed in the first material utilizing EMAT force. The dispersion process continues until spatial distribution of the second material enables the sample to meet a specified criterion. The chamber and/or the sample is electrically conductive. The EMAT force is generated by placing the chamber coaxially within an induction coil driven by an applied alternating current and placing the chamber and induction coil coaxially within a high field magnetic. The EMAT force is coupled to the sample without physical contact to the sample or to the chamber, by another physical object. Batch and continuous processing are utilized. The chamber may be folded within the bore of the magnet. Acoustic force frequency and/or temperature may be controlled.

The invention discloses a high-sensitivity microphone based on a quartz crystal resonator, which is on the basis of a force-frequency effect of the quartz crystal resonator, that is, if an oscillator of the quartz crystal resonator is subjected to the effect of a force or strain, the resonant frequency of the resonator changes in a linear manner along with changes of the force. The core of the invention is that a vibration diaphragm generates vibrations according to the size of pressure and different frequencies when being subjected to the pressure of sound waves, the vibration is converted into strain through a mechanical structure and acts on a quartz crystal, the quartz crystal resonator is enabled to generate frequency deviation so as to accomplish sound-electricity conversion, a vibration parameter of the diaphragm can be acquired through measuring the frequency deviation, and transmitted sound wave information can be further acquired. The microphone disclosed by the invention has the characteristics of high sensitivity, large frequency response range and small volume.