175 results about "Radiofrequency pulse" patented technology

The invention discloses a radio frequency on-chip test system and a radio frequency on-chip test method. The radio frequency on-chip test system comprises a probe temperature adjusting module, an instantaneous pulse acquisition module, a dynamic compensation module, a thermal isolation module, radio frequency measurement equipment and a bearing platform. Wherein the probe temperature adjusting module is used for independently adjusting the temperature of a probe to a target value; the instantaneous pulse acquisition module is used for transmitting a radio frequency pulse signal and acquiring a radio frequency parameter when the probe is in contact with the normal temperature calibration sheet; the dynamic compensation module dynamically corrects the radio frequency parameters based on the real-time temperature of the probe; the thermal isolation module is used for reducing heat exchange between the probe and the external environment; the radio frequency measuring equipment is used for collecting and analyzing the radio frequency parameters; the bearing platform is used for bearing the normal temperature calibration sheet or the device to be tested. Through the synergistic effect of multiple modules, the problem of test errors caused by temperature fluctuation is effectively solved, and the precision and stability of radio frequency on-chip test are remarkably improved.

The invention discloses a high-spatial-resolution distributed optical fiber sound wave sensing system based on FPGA real-time demodulation. The system comprises a narrow linewidth laser source module, a first coupler, a high-bandwidth sweep frequency signal modulation module, a circulator, a coherent receiving and photoelectric conversion module and an FPGA integrated module. A laser source emitted by the narrow linewidth laser source module is divided into about 10% of reference light and about 90% of detection light through the first coupler. The FPGA integrated module is connected with the high-bandwidth sweep frequency signal modulation module, and transmits a sweep frequency radio frequency pulse signal and a frequency shift radio frequency pulse signal to the high-bandwidth sweep frequency signal modulation module; the high-bandwidth sweep frequency signal modulation module is connected with the sensing optical fiber through the circulator so as to output sweep frequency optical pulses; the sensing optical fiber is connected with the coherent receiving and photoelectric conversion module through the circulator to transmit Rayleigh backscattered light; the coherent receiving and photoelectric conversion module is connected with the FPGA integrated module, and the FPGA integrated module carries out signal processing to obtain vibration information on the optical fiber.

The invention discloses a magnetron sputtering coating method with uniform coating and high target material utilization rate, and belongs to the technical field of film preparation, and the method realizes high-precision coating through whole-process collaborative optimization of pretreatment, sputtering, deposition and post-treatment. The substrate is cleaned in cooperation with radio-frequency pulse focusing bombardment; an electromagnetic coil group containing a temperature compensation coil is used for target sputtering, a magnetic field is dynamically adjusted in combination with laser profile sensing and a PID self-adaptive algorithm, and a direct current pulse-radio frequency composite power supply is matched to solve the target problem; in the deposition stage, a quartz crystal instrument is used for closed-loop film thickness control, metal film pulse gas supply and compound film reaction gas phase adjustment; gradient temperature rise is carried out according to data of an X-ray stress meter in post-treatment, and argon is used for dynamic protection and impurity prevention. According to the magnetron sputtering coating method with uniform coating and high target material utilization rate, the uniformity of coating and the target material utilization rate are improved, and the technological adaptability and stability of coating are improved.

The invention belongs to the field of particle accelerator microwaves, and particularly relates to a C-band compact spherical microwave pulse compression device which comprises a shell, a dual-polarization mode coupler and a circular waveguide, a spherical energy storage cavity is formed in the shell, and the circular waveguide and the spherical energy storage cavity are communicated through a coupling hole; the dual-polarization mode coupler comprises a rectangular waveguide, a butterfly-shaped matching section and a cylindrical matching section. According to the klystron radio frequency pulse compression circuit, the radio frequency pulse with the pulse width of 2.5 microseconds of the klystron can be compressed to 300ns, the average power gain in a single pulse is more than 4 times, the peak power gain is 6.3 times, and the compression efficiency is about 54%. According to the dual-polarization mode coupler, the functions of power distribution, mode conversion and polarization mode generation are synchronously realized, a TE10 mode in a rectangular waveguide is converted into two polarization TE11 modes which are equal in amplitude and orthogonal in phase, and then the two orthogonal TE114 modes are excited in a spherical energy storage cavity.

The present disclosure relates to a target volume tracking method and a computer device. The method includes: determining an isocenter location corresponding to the target volume in a scout image of an object, and obtaining the spatial position of the treatment head in the radiotherapy device, and then determining the at least one slice on the scout image based on the isocenter location and the spatial position, so as to control the magnetic resonance scanner to radiate a RF pulse which excites the at least one slice to obtain a tracking image of the object; the tracking image includes the target volume.

The invention relates to a computer-implemented method for operating a magnetic resonance device (20) during a recording process according to a recording protocol, which comprises a plurality of sequence sections (1) of a magnetic resonance sequence in at least one repetition, wherein each sequence section (1) comprises a preparation module (8) and a readout module (10), and each readout module (10) comprises a plurality of readout submodules (2), in each of which radio-frequency pulses (12, 13) precede readout periods (6) for recording magnetic resonance data, wherein - in each readout module (10) at least one navigator submodule (11) is used to record navigator data of the sequence section (1), - for each sequence section (1), correlation information is determined by comparing the navigator data record of the sequence section (1) with at least one navigator data record of a further sequence section (1), and - the correlation information is evaluated to select sequence sections (1) whose magnetic resonance data are discarded and / or to assign a weighting to the magnetic resonance data of at least some of the sequence sections (1) before reconstructing a magnetic resonance image.

In a general aspect, a radar method includes transmitting an outgoing series of RF pulses toward a target region. The radar method also includes receiving an incoming series of RF pulses that is based on the outgoing series of RF pulses after passing through the target region. The radar method additionally includes producing, by operation of a vapor cell system, output signals that are based on incoming series of RF pulses and the laser signals interacting with a vapor of the vapor cell system. The radar method also includes operations of a signal processing system, such as generating response data, determining a Doppler shift, and determining a velocity of an object in the target region. The response data includes transient response data that represents transient responses of a vapor in the vapor cell system to respective phase changes in the incoming series of RF pulses.

The present disclosure describes a device, system, and methods for low-field magnetic resonance (MR) imaging. For example, a method for low-field MR imaging can include projecting a primary static magnetic field in a field of view, projecting a secondary static magnetic field to pre-polarize a first fluid moving toward the field of view, and acquiring a first image of the first fluid in the field of view based on a first RF pulse sequence. The method can further include projecting a tertiary static magnetic field to pre-polarize a second fluid moving toward the field of view and acquiring a second image of the second fluid in the field of view based on a second RF pulse sequence. The first image can be subtracted from the second image to generate a flow image of an object of interest positioned in the field of view.

The present disclosure provides an example method for using an MRI system electrically coupled to a computing device. The method includes generating, via the MRI system, an echo-shifted echo-planar imaging with blip up / down acquisition (“esEPI-BUDA”) pulse sequence including a first radiofrequency (“RF”) pulse and a second RF pulse, the first RF pulse followed by a first echo-train that is interleaved with the first and the second RF pulses, and the second RF pulse followed by a second echo-train such that the first and the second echo-trains have opposite phase-encoding blip gradient polarities to traverse echo planar imaging (“EPI”) k-space in a reversed order. In response to the pulse sequence being generated, the MRI system acquires two k-space datasets within a single shot and corrects image distortion, via the MRI system, based on the two acquired k-space datasets.

A time-efficient diffusion magnetic resonance imaging systems and methods are provided that can produce multiple diffusion-weighted images with different b-values in one repetition time, and / or multiple diffusion-weighted images with different diffusion times in one repetition time, both by utilizing a train of stimulated echoes. Each stimulated echo in the train of stimulated echoes is generated by a re-excitation radio-frequency (RE) pulse with a variable flip angle, following an initial 90° excitation RE pulse and a subsequent 90° restoration RE pulse.

The invention relates to NFC device detection. A device operating in a card emulation mode detects a first near field communication burst emitted by an external device. The first near field communication burst includes a first pulse of duration Tw. The device operating in card analog mode transmits a radio frequency pulse in response to an external device as a result of detecting a first pulse of a first near field communication burst. The duration of the radio frequency pulse is less than or equal to the duration Tw and is transmitted within a period of time less than or equal to 10 [mu] s from the leading edge of the first pulse of the first near field communication burst.

A method for optimization of an RF pulse for exciting spins in a slab in a magnetic resonance examination is provided. The RF pulse is to be played out with a coil having a plurality of independent parallel transmit elements. The method includes receiving complex B1+ field sensitivity maps for the plurality of parallel transmit elements and dividing the slab into at least two sub-slabs. For each sub-slab, B1+ shimming is performed to optimize the RF shim settings for the plurality of parallel transmit elements. The optimized RF shim settings are combined for each sub-slab to create a multiband RF pulse that simultaneously excites the spins in the complete slab.

The invention discloses a preparation method of a low-temperature plasma plating and permeating modified layer on the surface of a metal mold. The preparation method comprises the following steps: S1, precise pretreatment of a base body: sequentially carrying out mechanical grinding and polishing and ultrasonic cleaning on the base body, and then drying and putting the base body in a vacuum chamber; s2, plasma activation: after vacuumizing, introducing mixed gas of argon and hydrogen, generating glow discharge under the action of a pulse power supply, and performing sputtering activation on the surface of the substrate; s3, gradient transition layer plasma deposition is conducted, specifically, a pulse direct-current plasma source is adopted, a Ti target and a Cr target serve as sputtering sources, and a transition layer with components changing in a gradient mode is prepared; s4, plating and permeating a multi-element synergistic functional layer: preparing the functional layer by adopting a radio frequency-pulse direct-current composite plasma source, namely a Ti target, a Cr target, a Si-Al alloy target and a rare earth element target through synergistic sputtering; and S5, post-treatment optimization: performing vacuum cooling to room temperature after low-temperature annealing treatment to obtain a final modified layer. The permeation modified layer prepared by the method has high binding force, high hardness, high wear resistance and salt spray corrosion resistance.

The utility model discloses a radio frequency device for regulating and controlling skin temperature, which comprises a radio frequency signal generator for transmitting a radio frequency pulse signal and a pulse excitation signal for regulating and controlling the skin temperature; the electrode is used for receiving the radio-frequency pulse signal and generating a radio-frequency heat effect into the skin; the temperature sensor is arranged on the electrode or near the electrode and is used for detecting real-time temperature data of the skin in real time; the controller is used for controlling the radio frequency signal generator to output the pulse excitation signal for exciting the skin to reach the target temperature through one or more times based on the difference value between the temperature data and the target temperature; at least one of duty ratio, voltage and power of the pulse excitation signal is different from that of the radio frequency pulse signal, and the pulse width of the pulse excitation signal is smaller than that of the radio frequency pulse signal. When the real-time temperature data of the skin is abnormal in temperature rise, the skin is stimulated by one or more pulse excitation signals, so that the problem of abnormal temperature rise of the skin is effectively solved.

The invention relates to a longitudinal relaxation time calculation method, nuclear magnetic resonance imaging equipment and a storage medium, and the method comprises the steps: executing a pulse sequence, and collecting a first multi-echo signal; the pulse sequence comprises a radio frequency pulse and a readout gradient, and the radio frequency pulse comprises a first excitation pulse and a plurality of second excitation pulses in a repetition time of the pulse sequence; the first multi-echo signal is a multi-echo signal acquired after executing a second excitation pulse; performing image reconstruction on the first multi-echo signal to obtain a multi-echo image; calculating target signal intensity according to a signal attenuation function and the information of the multi-echo image; and calculating the longitudinal relaxation time according to the target signal intensities of the plurality of repetition times. According to the invention, after a small number of first excitation pulses are applied, accurate longitudinal relaxation time distribution is obtained, and the problem of low calculation efficiency in the prior art is solved.

The present invention relates to the field of auxiliary medical technology, and discloses a cold spray control method for a radio frequency treatment system and a radio frequency treatment system. The method comprises: determining a first temperature change rate and a second temperature change rate of the skin tissue in the current treatment area; wherein the first temperature change rate characterizes the temperature response of the skin tissue in the current treatment area to the cooling pulse, and the second temperature change rate characterizes the temperature response of the skin tissue in the current treatment area to the radio frequency pulse; and determining the duration of a single cold spray of the current cooling pulse based on the first temperature change rate and the second temperature change rate. The present invention dynamically adjusts the cold spray duration based on the different responses of the skin tissue to temperature changes, thereby ensuring that the temperature of the skin tissue is always maintained within a safe and effective range, ensuring that while the skin tissue is effectively treated with radio frequency, damage to the skin tissue in the current treatment area is avoided.

The embodiment of the invention provides a magnetic resonance imaging method and system. The method may include acquiring magnetic resonance imaging data of a target object. Magnetic resonance imaging data may be acquired by applying a magnetic resonance imaging pulse sequence to a target object. The magnetic resonance imaging pulse sequence may include a single radio frequency pulse for exciting a first substance in a target object and suppressing a second substance in the target object. The method may further include reconstructing a magnetic resonance image of the target object based on the magnetic resonance imaging data.

A disclosed etching method includes (a) preparing a substrate on a substrate support in a chamber. The substrate includes a multilayer film including a plurality of first films and a plurality of second films that are alternately stacked with the plurality of first films, and a mask disposed on the multilayer film. The etching method further includes (b) etching one or more first films among the plurality of first films. The etching method further includes (c) etching one or more second films among the plurality of second films. In each of the (b) and (c), a pulse of a source radio frequency power for plasma generation and a pulse of an electric bias for ion attraction are intermittently or periodically supplied.

The invention relates to a preparation method of a high-hardness ultra-smooth TiN coating, which comprises the following steps: putting a workpiece into a vacuum chamber, vacuumizing the vacuum chamber, and then introducing Ar to carry out ion cleaning on the surface of the workpiece; sequentially depositing a Cr layer and a Ti layer on the surface of the workpiece by adopting a radio frequency sputtering technology; a TiN layer is prepared on the surface of a workpiece by adopting a pure ion plating technology, when pure ion plating is carried out, mixed gas of Ar and N is introduced into a vacuum chamber, auxiliary ionization is carried out on the mixed gas in the vacuum chamber, negative bias voltage is applied to the workpiece, the ionization rate of a Ti target is improved by adopting a radio-frequency pulse power supply, and an ion beam is filtered by using a bent pipe magnetic filter. According to the TiN coating prepared through the method, the hardness can be stably higher than 3000 HV, the binding force on a high-speed steel base material is larger than 50 N, and the binding force with the base material is remarkably improved; the N content in the prepared TiN coating is larger than 45%, the ionization degree is very high, compactness is good, and the surface roughness Ra is smaller than 10 nm.

A computer-implemented method for operating a magnetic resonance device during the acquisition of magnetic resonance data from an examination region of an examination object may use a magnetic resonance sequence. The MR sequence may include a saturation section in which, by means of a saturation radiofrequency pulse which is generated when a saturation gradient pulse is applied, a saturation with respect to a spin species that is to be imaged is performed in at least one first saturation region. The saturation radiofrequency pulse may be designed as a multiband pulse by means of which, in addition, in at least one second saturation region, the magnetization with respect to a second spin species that is not to be captured is saturated.

Systems and methods are provided for producing diffusion-weighted images of a subject using a magnetic resonance imaging (MRI) system. The method includes performing a stimulated echo preparation module using non-selective radio-frequency (RF) pulses designed to induce a stimulated echo, performing an acquisition module that includes a multi-slice acquisition of MR data in the presence of diffusion gradients, and reconstructing the diffusion-weighted images of the subject from the MR data.

The invention discloses a method of imaging an object (10) placed in a magnetic field, comprising: subjecting the object (10) to a contrast preparation sequence (PRE) comprising at least one preparation radiofrequency, RF, pulse to non-selectively or selectively, partially or completely manipulate nuclear magnetization; subjecting the object (10) to an imaging sequence (IM) comprising at least one excitation RF pulse and switched magnetic field gradients to generate magnetic resonance, MR, signals, wherein the imaging sequence (IM) starts immediately after the preparation sequence (PRE) and samples a central portion of k-space (C) during a first time interval (TI1) encompassing a target time point at which the nuclear magnetization assumes a desired state after the contrast preparation sequence (PRE), and subsequently samples peripheral portions (PN, PP) of k-space during a second time interval (TI2); acquiring the MR signals from the object (10); and reconstructing an MR image from the acquired MR signals, wherein the visibility of particular tissues, structures, or pathological conditions within the object (10) is enhanced in the MR image by the contrast preparation sequence (PRE). A system is further disclosed, comprising a computational system configured to perform the method.

In an example, a method includes controlling electrical current to an actuation coil disposed about an elongate flexible body of a device within a field of view of magnetic resonance (MR) imaging system. The MR imaging system can be controlled to provide radio frequency pulses at one or more off-resonant frequencies to excite off-resonance spins near the actuation coil, such that the acquired MR data is representative of the off-resonance excitation. MR data can be provided based on MR signals acquired by the MR imaging system, in which at least some of the MR data includes the MR signals with the device within the field of view. Images can be reconstructed based on the MR data to provide reconstructed image data and localization data can be provided representative of at least one of a location, orientation and / or shape of the device based on the reconstructed image data.

The present application relates to the technical fields of radio frequency pulse signal source generating circuit, and particularly relates to a radio frequency pulse signal source generating circuit, comprising a frequency source module, a radio frequency switch module, a voltage-controlled gain adjustable module, a digital control attenuation module and a main control module, the main control module is electrically connected with the frequency source module and the digital control attenuation module, the voltage-controlled gain adjustable module is electrically connected with the radio frequency switch module and the digital control attenuation module, the frequency source module communicates with the main control module to obtain corresponding frequency setting code, and the frequency source module sets the corresponding register of the frequency source module according to the data obtained from the main control module; the radio frequency switch module and the voltage-controlled gain adjustable module are set to realize pulse modulation of signals, the signals modulated by the radio frequency switch module are continuously sent to the voltage-controlled gain adjustable module, finally the modulated radio frequency signals are sent to the digital control attenuation module, the purpose of controllable power of the signals sent to the receiver is realized, and then high suppression degree of continuous wave is realized.

This disclosure provides a radio frequency (RF) transmitting device, a magnetic resonance imaging (MRI) system, and an operating method. The RF transmitting device for the MRI system includes: a transmitting coil comprising a plurality of legs extending axially, the plurality of legs being arranged circumferentially at equal intervals around the axis of the transmitting coil; the plurality of legs including a plurality of first legs and a plurality of second legs arranged alternately, wherein each of the plurality of first legs includes a first portion and a second portion electrically isolated from each other; and a plurality of RF amplifiers, each of the plurality of RF amplifiers being integrated on one of the plurality of first legs, and the phase of the RF pulse signal output by each RF amplifier being individually adjustable.

A method for recording scan data of an examination object which includes spins of at least two different spin species by means of a magnetic resonance system. The method includes: radiating in a composite RF pulse, for example, a binomial pulse comprising at least two subpulses; switching bipolar slice selection gradients so that successive subpulses of the composite RF pulse are encoded with differently polarized slice selection gradients; recording as scan data magnetic resonance signals triggered by the composite RF pulse; and storing and / or further processing the recorded scan data, wherein the subpulses are radiated in at a frequency that is detuned by a detuning shift relative to a resonance frequency of a spin species that is to be represented, such that by way of the detuning shift a linear evolution of the phase over the temporal progression of the composite RF pulse results.

The application relates to the technical field of radio frequency signal processing, in particular to a radio frequency absorption rate determination method, device and computer readable storage medium. The method comprises the following steps: collecting instantaneous radio frequency output power in a single radio frequency pulse duration at a set time interval; calculating an equivalent pulse width of the single radio frequency pulse according to all the collected instantaneous radio frequency output powers; calculating pulse output energy of the single radio frequency pulse according to the equivalent pulse width; and calculating the radio frequency absorption rate of the radio frequency in a target time length according to the pulse output energy of the single radio frequency pulse. The method collects the instantaneous radio frequency output power of a single radio frequency pulse, determines the equivalent pulse width of the single radio frequency pulse, calculates the radio frequency absorption rate based on the equivalent pulse width, improves the accuracy of the radio frequency absorption rate calculation, and thus more effectively prevents the target, especially the target subjected to magnetic resonance detection, from being damaged due to excessive heat.

The invention belongs to the field of geotechnical engineering thermal-mechanical coupling experiment systems, and particularly relates to a buried heat storage-frozen soil hydrothermal coupling performance test experiment system. A magnet, a gradient unit and a radio frequency coil are utilized to form a nuclear magnetic resonance imaging assembly, and on the premise that a frozen soil structure is not disturbed, the structure of the frozen soil is optimized; high-resolution imaging is carried out on temperature distribution, moisture migration and pore evolution in the frozen soil; the time sequence of the magnetic field, the gradient field and the radio frequency pulse is accurately controlled through the control unit, the interaction process between the heat storage water body in the frozen soil and the freeze-thaw interface can be dynamically captured, the heat transfer path and the water vapor migration behavior are synchronously analyzed, and the temporal-spatial resolution and consistency of experimental data are improved; the corrugated pipe is connected with the constant-temperature bath to simulate the freeze-thaw environment of frozen soil, the external heat preservation cabin and a water source provided by the Markov bottle are matched, the dual control conditions of cold and hot disturbance and water supply are achieved, and the long-term disturbance and response mechanism of a heat storage system to the hot and humid state of the frozen soil in actual engineering is effectively simulated.

Disclosed in the present invention are a 3D navigator-based 3D gradient spin-echo diffusion imaging method, and a device. The method comprises: first, using a global saturation module to destroy previous residual transverse magnetization; second, by means of a diffusion encoding module, embedding a pair of trapezoidal cosine oscillation gradients or pulse gradients into radio frequency pulses of 90°x-180°y-90°-x, and separating diffusion encoding from signal acquisition; then using a fat saturation module to suppress a fat signal; using a 3D gradient spin-echo readout method to acquire an image signal; and finally, acquiring a 3D navigation echo signal in the last spin echo for correcting a phase error between multiple excitations. The present invention can effectively eliminate phase errors between multiple acquisitions and realize high-resolution whole-brain diffusion imaging. Compared with 2D echo planar imaging, the present invention increases the signal-to-noise ratio of diffusion magnetic resonance imaging, thereby supporting higher-resolution whole-brain 3D diffusion magnetic resonance imaging.