12 results about "Rf excitation" patented technology

This invention discloses a multi-level collaborative SAW exhaled breath detection system and method based on a large language model, belonging to the field of SAW detection technology. The system includes a precision RF excitation control layer, an IoT gateway layer, and a cloud-based AI analysis layer. Data interaction between the three layers is achieved through a heterogeneous communication protocol stack. The precision RF excitation control layer includes a microcontroller, a DDS frequency synthesizer, and an SAW resonator; the microcontroller has a built-in pre-verification module. The IoT gateway layer includes a dual-core processor, a wireless communication module, and an I / O interface. 2 The system features an S-channel audio interface and a dual-core processor with a heterogeneous architecture. The cloud-based AI analysis layer includes speech recognition services, large language model inference services, a utility function definition library submodule, and a command string generation submodule. The system has an end-to-end device-level mapping channel from user speech to the DDS frequency synthesizer's frequency tuning word register. This invention lowers the operational threshold for precision SAW inspection and adapts to on-site inspection scenarios.

The invention relates to a method of MR imaging of an object (10) positioned in an examination volume of a MR device (1). It is an object of the invention to enable efficient spiral MR imaging without blurring artefacts, even in situations of strong B0 inhomogeneity. The method of the invention comprises the following steps: —subjecting the object (10) to an imaging sequence comprising at least one RF excitation pulse and modulated magnetic field gradients, —acquiring MR signals along two or more planar spiral k-space trajectories (31, 32, 33), wherein the radial k-space speed, i.e. the rate of variation of the radial distance from the spiral origin is essentially constant along each planar spiral k-space trajectory, and wherein the two or more k-space trajectories (31, 32, 33) are offset in-plane from each other, and—reconstructing an MR image from the acquired MR signals. Moreover, the invention relates to a MR device (1) and to a computer program for a MR device (1).

In a method for improving the recording of measurement data of an object under inspection, the method includes loading desired imaging parameters and a desired flip angle for recording the measurement data by means of a recording method, wherein the gradient to be switched for position encoding of the measurement data has its full intensity during the incident RF excitation pulse. A quantization value of a desired interference for the recording method is determined based on the desired imaging parameters, and a check on the feasibility of correcting for the interference is performed based on the quantization value and the desired flip angle.

A system for RF based frequency encoding utilizing a Bloch-Siegert shift, includes a controller, an RF encoding system, and an injection transformer simultaneous transmit and receive filter. The controller generates RF excitation pulses, RF based frequency encoding pulses, and a cancellation signal. The RF encoding system includes one or more RF coils configured to transmit the RF excitation pulses and RF based frequency encoding pulses, and to receive an MR signal from the subject where the MR signal includes a leakage signal induced by the RF based frequency encoding pulses. The injection transformer simultaneous transmit and receive filter is in signal communication with the controller and the RF encoding system. The injection transformer simultaneous transmit receive filter is configured to receive the cancellation signal, the MR signal including the leakage signal, and to cancel the leakage signal from the received MR signal to generate a filtered MR signal.

An apparatus for multiphoton parallel transmission for magnetic resonance imaging (MRI) of a subject, includes a radio frequency (RF) transmit coil, a single-channel universal excitation coil positioned outside of the RF transmit coil, and a processor device coupled to the RF transmit coil and the single-channel universal excitation coil. The RF transmit coil is configured to perform at least one RF excitation pulse of a multiphoton parallel transmit excitation comprising a multiphoton excitation pulse configured to correct spatial inhomogeneities and the single-channel universal excitation coil is configured to perform a low-frequency excitation pulse of the multiphoton excitation pulse. The processor device is configured to control current waveforms provided to the RF transmit coil to perform the at least one RF excitation pulse and to control current waveforms provided to the single-channel universal coil to perform the low frequency excitation pulse of the multiphoton excitation pulse.

In a method for measuring brain free water content, in response to an RF excitation field generated on the basis of a magnetic resonance fingerprinting sequence and applied to the brain, an equilibrium magnetization mixed term (M0) signal is acquired from radiation emitted by each excited voxel of the brain, to obtain an M0 value of each voxel of the brain; a receive coil sensitivity (RP) value of each voxel of the brain is acquired; the M0 value of each voxel of the brain is divided by the RP value of the corresponding voxel to obtain a proton density (PD) value of each voxel of the brain; a PD value of cerebrospinal fluid is taken to be a reference PD value; and the PD value of each voxel of the brain is divided by the reference PD value to obtain the free water content of each voxel of the brain. The method advantageously increases the speed and accuracy of measurement of brain free water content.

A method according to the invention for acquiring T2*-weighted measurement data of a test object using a magnetic resonance system comprises the steps: - irradiating a first RF excitation pulse to excite spins in a first layer in the test object, - switching gradients to generate at least one gradient echo signal, - after an echo time following the irradiation of the first RF excitation pulse, acquiring a first gradient echo signal from the first layer, - after the irradiation of the first RF excitation pulse and before the elapsed echo time following the first RF excitation pulse, irradiating at least one further RF excitation pulse to excite spins in a further layer,wherein, before the application of a further RF excitation pulse and after each RF excitation pulse preceding the further RF excitation pulse, a pre-rephasing gradient of a moment corresponding to the further RF excitation pulse following the pre-rephasing gradient is switched, - recording generated further gradient echo signals from further layers. By switching the pre-rephasing gradients according to the invention, gradient echo signals of the spins of different layers excited by the first RF excitation pulse and the at least one further RF excitation pulse can be separated. Thus, the echo time TE, which elapses until a first gradient echo signal is measured after the first RF excitation pulse, can be used to generate and measure further gradient echo signals in further layers after the first gradient echo signal, which increases the readout efficiency.

A method for generating a magnetic resonance image of a subject using a magnetic resonance imaging (MRI) system includes receiving, using the MRI system, at least one parameter for a multiphoton parallel transmit excitation comprising a multiphoton excitation pulse configured to correct spatial inhomogeneities and performing, using the MRI system, a pulse sequence comprising the multiphoton parallel transmit excitation to acquire data from the subject. The multi photon excitation pulse of the multi photon parallel transmit excitation is performed using a radio frequency (RF) coil and a set of one or more shim coils of the MRI system. The method further includes generating, using a processor, an image of the subject using the acquired MR data. In some embodiments, the multiphoton excitation pulse includes an off-resonance RF excitation pulse performed using the RF coil and a plurality of low-frequency excitation pulses performed using the set of one or more shim coils. The plurality of low-frequency excitation pulses are performed simultaneously with the off-resonance RF excitation pulse.

The invention relates to a method of MR imaging of at least a portion of a body (10) of a patient placed in an examination volume of an MR system (1). It is an object of the invention to provide an improved fast gradient echo imaging technique with the ability to obtain angiographic information. The method of the invention comprises the steps of subjecting the body portion to a magnetization preparation RF pulse (MP); subjecting the body portion to a gradient echo imaging sequence comprising a series of RF excitations (EP) after a preparation delay (TD), wherein a phase encoding gradient (PE) and a refocusing gradient (RO) and at least one bipolar velocity encoding gradient (VE) pair are applied in repetition time intervals (TR) between successive RF excitations (EP) to sample a predefined region of k-space and generate gradient echoes in each repetition time interval (TR); acquiring echo signals from the body portion; reconstructing a morphological MR image of the body portion from the acquired echo signals; and deriving phase contrast angiographic information from the phase imparted on the echo signals by the velocity encoding gradients (VE). Furthermore, the invention also relates to an MR system (1) and a computer program.

This invention discloses an MBE (molecular beam epitaxy) source furnace and its thin film growth method, belonging to the field of semiconductor thin film preparation technology. The source furnace includes a gas mass flow controller, a plasma initiation device, a plasma generation cavity, and a plasma termination device connected sequentially along the beam direction. The outer wall of the plasma generation cavity is surrounded by a cross-distributed RF electrode system for efficient and uniform gas ionization. The plasma termination device is a double-layer batching disk structure used to shape the plasma into a uniform molecular beam. The method for growing thin films using this source furnace includes steps such as substrate heating, introduction of reactive gas, RF excitation to generate plasma, and beam application to the substrate for thin film growth. This invention effectively solves the problems of low ionization efficiency and non-uniform beam flow in traditional plasma sources, and is particularly suitable for the preparation of high-quality nitride and oxide semiconductor single-crystal thin films.

This invention discloses a wireless human body temperature measurement tag based on RFID technology for use in the field of temperature measurement devices. It highly integrates three major functional modules—RF excitation, local data processing, and remote transmission—into a single device—an RF transmitting base station. This enables long-distance, low-power monitoring, solving the pain point of short communication distance in purely passive RFID systems. Furthermore, the RFID temperature tag requires no battery, achieving extremely low maintenance costs throughout the system's lifecycle. Additionally, the introduction of an STM32 microcontroller chip at the base station for data preprocessing enables local data cleaning and verification, effectively filtering out invalid or erroneous data, reducing data redundancy and error rates transmitted to the cloud, and improving the overall system's data quality and transmission efficiency. Finally, a fixing unit is provided for the RFID temperature tag, allowing it to be fixed to clothing, enabling continuous long-term use and reducing the cost of using the RFID temperature tag.

An apparatus for controlling electromagnetic (EM) radiation emitted from a magnetic resonance imaging (MRI) system having a magnet assembly having a superconducting magnet and a radio frequency (RF) shield includes an RF birdcage body coil positioned in the magnet assembly proximate to an inner radius of the RF shield and configured to apply one or more RF excitation pulses, at least one radiation control array positioned in the magnet assembly and configured to control EM radiation generated by the RF birdcage body coil during application of the one or more RF excitation pulses, and a processor device coupled to the RF birdcage coil and the at least one radiation control array and configured to control current waveforms provided to the RF birdcage body coil and to the at least one radiation control array.