101 results about "Radiofrequency pulse" patented technology

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 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 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.

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.

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.

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.

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.

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.

Provided in the present invention is a relaxation exchange magnetic resonance imaging (REXI) sequence, comprising: a filtering module, consisting of a 90° excitation radio frequency pulse and a 180° refocusing radio frequency pulse; an exchange module, consisting of a 90° excitation radio frequency pulse and an exchange delay; and a detection module, consisting of a 90° excitation radio frequency pulse and a plurality of 180° refocusing radio frequency pulses. Paired crusher gradient pulses are applied to the filtering module and the detection module, and a spoiler gradient pulse is applied to the exchange module. Further disclosed in the present invention is an acquisition and analysis method for the REXI sequence: during REXI acquisition, the echo time of the filtering module is fixed, and only the exchange delay time of the exchange module and the echo time of the detection module are changed; and during REXI analysis, a dual-chamber exchange model is used for fitting data. Further disclosed in the present invention is the use of the REXI sequence and the acquisition and analysis method thereof in measuring transmembrane transport of cerebrospinal fluid by magnetic resonance imaging, which is especially suitable for magnetic resonance imaging for rapidly measuring the speed of molecular exchange between a short T2 component and a long T2 component in a dual-component system.

The invention discloses a radio-frequency pulse power supply for a radio-frequency carbon dioxide laser, and the power supply comprises an input unit which inputs a radio-frequency signal; the first-stage power amplification unit is used for receiving the radio frequency signal, amplifying power and outputting a first-stage amplified radio frequency signal; the first-stage power distribution unit receives the first-stage amplification radio frequency signal and equally divides the first-stage amplification radio frequency signal into two paths of first-stage distribution radio frequency signals with the same power for output; the second-stage power distribution units are arranged in pairs, receive the first-stage distribution radio-frequency signals, uniformly divide the first-stage distribution radio-frequency signals into two paths of second-stage distribution radio-frequency signals with the same power through voltage reduction and transformation, and output the two paths of second The second-stage power amplification unit receives one path of second-stage distribution radio frequency signal, amplifies power and outputs a second-stage amplification radio frequency signal; the power synthesis unit is used for receiving the four paths of secondary amplification radio-frequency signals and synthesizing the four paths of secondary amplification radio-frequency signals into high-power radio-frequency signals for output through boost transformation; and the output unit receives and outputs the high-power radio frequency signal. Through multi-stage amplification and multi-stage synthesis, pulse signal output with hundreds of watts to kilowatt peak power is realized.

To disclose a method for controlling plasma within a plasma processing chamber.SOLUTION: Multiple, sequential pulses of radiofrequency power are supplied to an electrode of a plasma processing chamber to control plasma within the plasma processing chamber. Each of the pulses of radiofrequency power includes a first duration over which a first radiofrequency power profile exists, immediately followed by a second duration over which a second radiofrequency power profile exists. The first radiofrequency power profile has greater radiofrequency power than that of the second radiofrequency power profile. The first duration is less than the second duration. And, the sequential pulses of radiofrequency power are separated from each other by a third duration. A radiofrequency signal generation system is provided to generate and control the multiple, sequential pulses of radiofrequency power.SELECTED DRAWING: Figure 4

To provide methods and systems for multi-level RF pulse monitoring and RF pulsing parameter optimization at a manufacturing system.SOLUTION: A method includes: pulsing a radio frequency (RF) signal within a processing chamber in accordance with a set of RF pulsing parameters; receiving sensor data from one or more sensors that indicates a multi-level RF pulse waveform; and identifying one or more peaks in the detected multi-level RF pulse waveform. Each identified peak corresponds to at least one RF signal pulse of the RF signal pulsing within the processing chamber. The method also includes: making a determination, based on the identified one or more peaks, whether the detected multi-level RF pulse waveform corresponds to a target multi-level RF pulse waveform; and providing an indication of whether the detected multi-level RF pulse waveform corresponds to the target multi-level RF pulse waveform to a client device.SELECTED DRAWING: Figure 2

The application discloses a parallel MPWM modulation method of 3X harmonic elimination, and relates to the technical field of wireless communication.The method comprises the following steps: based on the principle of harmonic elimination, input baseband signals are decomposed into four phase-controlled baseband modulation signals; the baseband modulation signals are subjected to digital up-conversion to obtain intermediate frequency signals; a parallel optimization module is set in a parallel MPWM algorithm, and the intermediate frequency signals are subjected to optimization processing based on the parallel optimization module to obtain four bit pulse sequence codes; the four bit pulse sequence codes are converted into four two-level radio frequency pulse signals; wherein, the sum of the four two-level radio frequency pulse signals is a required five-level radio frequency pulse width modulation signal, the center frequency of the five-level radio frequency pulse width modulation signal is a carrier frequency, and 3X harmonic is eliminated.The application can improve the signal-to-noise ratio, suppress harmonics, and widen the achievable carrier frequency of RF-PWM.

NFC Device Detection This description relates to a method comprising: - the detection, by a card-mode device (102), of a first burst of near-field communication emitted by an external device (104), the first burst comprising a first pulse of duration Tw; and - the emission, by the card-mode device in response to the external device following the detection of the first pulse of the first burst, of a radio frequency pulse of duration less than or equal to Tw, within a time interval less than or equal to 10 from a leading edge of the first pulse. Figure for the abstract: Fig. 1

Various systems and methods for T2-weighted chirp CPMG sequences and / or diffusion-weighted chirp CPMG sequences are disclosed herein. In one aspect, the method can include projecting a magnetic field toward a target object along a longitudinal axis and transmitting a radio frequency pulse sequence to a radio frequency coil assembly configured to selectively excite magnetization in the target object. The radio frequency pulse sequence can include a frequency-swept excitation pulse and a series of frequency-swept refocusing pulses following the excitation pulse. In some aspects, the radio frequency pulse sequence can include a series of refocusing pulses followed by a frequency-swept recovery pulse. In some aspects, the method can include transmitting a preparation radio frequency pulse sequence to the radio frequency coil assembly.

This invention discloses a magnetic resonance imaging (MRI) sequence translation communication control system and method. The system includes: a parameter customization module for receiving and verifying user-configured MRI parameters; a sequence generation module for generating MRI sequence files conforming to the Pulseq standard based on the verified parameters; a sequence translation module for translating the MRI sequence files into a TLV format hardware instruction stream according to the target spectrometer hardware configuration file; a hardware control module for writing the TLV instruction stream into the spectrometer hardware registers via an open hardware instruction bus, controlling the spectrometer to transmit radio frequency pulses, apply gradient fields, and acquire MRI signals; and a verification and feedback module for real-time monitoring of hardware execution status and data consistency verification. This invention solves the problems of complex hardware interfaces and poor sequence portability in existing MRI systems by constructing a closed-loop architecture of "parameter configuration - sequence generation - TLV translation - hardware execution," thereby improving the system's versatility, scalability, and control accuracy.

A system for performing arterial-spin labeling (“ASL”) includes at least one memory configured to store instructions and at least one processor configured to execute the instructions to cause the system to perform a labelling phase and a control phase. The labelling phase includes a first plurality of radio frequency (“RF”) pulses and each RF pulse of the first plurality of RF pulses has a frequency offset and a phase offset. The control phase includes a second plurality of RF pulses and each RF pulse of the second plurality of RF pulses has the frequency offset and the phase offset and alternating RF pulses of the second plurality of RF pulses has an additional phase shift.

To simultaneously collect and systematically evaluate information regarding free water and bound water within living organisms. [Solution] A magnetic resonance imaging apparatus according to one embodiment comprises a setting unit and a scanner. The setting unit sets a pulse sequence. The pulse sequence includes a plurality of sub-pulse sequences. The plurality of sub-pulse sequences collect MR (Magnetic Resonance) data corresponding to each of the plurality of echo signals generated after the application of MT (Magnetization Transfer) pulses and RF (radio frequency) pulses to the subject, using a UTE (Ultrashort Echo Time) sequence. The scanner collects MR data based on the pulse sequence set by the setting unit. The MR data corresponding to the first echo signal after the application of the RF pulse from among the plurality of echo signals of at least one sub-pulse sequence is used for the analysis of both bound water and free water in the subject.

This invention relates to a high-field magnetic resonance imaging (MRI) method, which uses an imaging sequence with excitation and retraction pulses for MRI. A radio frequency (RF) pulse is applied to the human tissue being examined in a main magnetic field, exciting the target region of the tissue. The precession frequencies of the target imaging material and interfering imaging material under the main magnetic field are obtained in advance, and the retraction pulse frequency parameters for non-retraction of the interfering imaging material are determined based on the two obtained precession frequencies. MRI is then performed using the imaging sequence with the determined parameters. By using the first precession frequency of the target imaging material under the main magnetic field strength as the center frequency of the retraction pulse, the target imaging interference signal is suppressed. This achieves reasonable suppression of the MRI signal of the interfering imaging material without the need for additional pulses, overcoming the problems of traditional signal suppression being sensitive to the RF field and poor imaging results caused by RF field inhomogeneity.

Embodiments of the present application provide a magnetic resonance scanning and imaging method, and a magnetic resonance imaging system. The method includes: determining a pulse to be adjusted in a scan sequence, the pulse to be adjusted including a first radio-frequency pulse and a first gradient pulse applied along with the first radio-frequency pulse; determining an adjustment factor based on the first gradient pulse and a minimum repetition time related to a specific absorption rate of radio-frequency energy; adjusting the scan sequence based on the adjustment factor; and, using the adjusted scan sequence, performing a diagnostic scan on a site to be examined, to obtain a magnetic resonance image.

A method and a magnetic resonance imaging (MRI) system improve an MRI signal from a magnetization of interest. The method includes performing an MRI pulse sequence containing three consecutive radio frequency (RF) elements, namely, a first element that is an inversion-recovery pulse sequence characterized by a time of inversion, a second element that is an image-encoding pulse sequence starting at the time of inversion with an excitation RF pulse followed by an image-encoding gradient and a data sampling. The second element is followed by a third element. An MRI signal generated by the object and sampled by image readout blocks applied to the object by the MRI system during each repetition time, is acquired. From the MRI signal, an image of the object is reconstructed. The third element is a modified driven-equilibrium (mDE) pulse sequence configured for achieving a conversion of a transverse magnetization component.

A system and method for in-situ atomic layer etching and high-selectivity etching based on radicals is disclosed. The system is provided with a switchable blocking capacitor, which eliminates the plasma sheath by grounding the electrostatic chuck (ESC), and also uses a high-power, short radio frequency pulse technology for the plasma source. These features enable a radical-based process with significantly reduced ion effects during the surface modification step of ALE and the radical-based HSE step. The invention also relates to the application scenarios of in-situ ALE and HSE processes.

The application discloses a kind of based on signal phase's magnetic resonance radio frequency gain calibration method, comprising the following steps: S1: design a fermi pulse, calculate corresponding radio frequency amplitude;S2: design pre-scan sequence;S3: the actual maximum radio frequency amplitude of fermi pulse under fixed radio frequency gain is measured to the data acquisition;S4: according to the actual maximum radio frequency amplitude measured and the maximum integer value of fermi pulse waveform file, the radio frequency conversion coefficient of radio frequency system at this time is calculated;S5: predict the flip angle of any radio frequency pulse under a certain radio frequency gain preset value;S6: according to multiple radio frequency gain preset values and corresponding flip angle, the radio frequency gain value required for target flip angle is predicted.The application is also disclosed a kind of based on signal phase's magnetic resonance radio frequency gain calibration system.The radio frequency conversion coefficient of radio frequency system is indirectly measured by more stable signal phase information, and will not be influenced by background magnetic field inhomogeneity, tissue signal attenuation and other environments.

The application provides a small animal sciatic nerve magnetic resonance coil and an imaging method, and the method comprises the following steps: filling a high-concentration sugar syrup solution at the bottom of the magnetic resonance coil and performing constant temperature control; placing a small animal in a prone position in the high-concentration sugar syrup solution and discharging air in the gap between the lower limbs and below the abdomen of the small animal; after performing magnetic resonance positioning scanning to determine the main sequence scanning range, starting the main sequence scanning, suppressing the flow tissue signal through a pre-pulse combination, exciting the tissue by using a radio frequency pulse with preset parameters, acquiring echo signals by combining a fast spin echo technology and filling K space, and obtaining scanning original data; performing preprocessing on the scanning original data and accurate segmentation of the sciatic nerve and spinal nerve to obtain a segmentation result; and completing three-dimensional model reconstruction, optimization and multi-modal fusion visualization based on the segmentation result to obtain an image scanning result. The application is suitable for small animals, is accurate in imaging, can effectively suppress various kinds of artifacts, and can be widely applied to sciatic nerve imaging scenarios of small animals.