Abstract: The present disclosure relates to a beam measuring device, a sample processor including the beam measuring device, and a method of measuring a beam using the beam measuring device. The beam measuring device includes a detection unit and a light impediment unit. The light impediment unit is located between the detection unit and a light source, and is configured to generate a shadow area on the detection unit by blocking transmission of part of a beam coming from the light source. The detection unit is configured to measure the shadow area, and to determine whether the beam is divergent or inclined with respect to a predetermined optical axis based on the measurement of the shadow area. The beam measuring device may shorten the optical detection channel and ensure the detection accuracy, thereby having a compact structure. In addition, the beam measuring device may measure divergence angle and directionality, respectively.

Abstract: The invention relates to a cuvette assembly for a sample processor, a flow cell for a sample processor comprising the cuvette assembly, and a sample processor comprising the cuvette assembly or the flow cell. The cuvette assembly comprises a cuvette body and a reflector. The cuvette body is in the shape of a rectangular parallelepiped and comprises a sample detection channel vertically penetrating the cuvette body. The cuvette body has long sides and short sides in a horizontal section. The reflector has a flat surface attached to a first side surface extending along one of the long sides of the cuvette body and a spherical surface that is opposite to the flat surface and has a truncated lower half. The reflector is positioned so that it is flush with a lower surface of the cuvette body and a center of sphere of the spherical surface falls into the sample detection channel, and the reflector extends along the long side and exceeds the short side.

Abstract: A detection circuit for instantaneous voltage drop and an on-board diagnostic system. The detection circuit comprises two RC circuits, each of the RC circuits comprises a first resistor, a second resistor, and an energy storage capacitor; a first end of the first resistor is used for receiving a to-be-detected voltage, and a second end thereof is connected to a first end of the second resistor; the energy storage capacitor is connected in parallel with the second resistor; the first end of the second resistor forms an output end of the RC circuit, and the output end is connected to an input end of the comparator; an output end of the comparator is connected to the determination unit; in the two RC circuits, the resistance ratios of the second resistors to the first resistors are different, the capacitances of the energy storage capacitors are different.

Abstract: Methods, systems, and computer-readable storage mediums for correcting time in a nuclear magnetic resonance device are provided. In one aspect, a method includes obtaining respective transmission time delays of three gradient pulse signals that are generated by a three-dimensional gradient subsystem of the nuclear magnetic resonance device and include a slice-selection gradient signal, a phase-encoding gradient signal, and a frequency-encoding gradient signal, determining a time correction value according to the obtained respective transmission time delays of the three gradient pulse signals, and correcting a respective output time of each of the three gradient pulse signals, an output time of a radio-frequency (RF) pulse signal generated by a RF transmitting subsystem of the nuclear magnetic resonance device, and a reception time of a magnetic resonance signal received by a RF receiving subsystem in a scanning cycle according to the determined time correction value.

Abstract: A method for determining a position of an RF coil in a magnetic resonance imaging (MRI) system is disclosed. As an example, a center of a field of view (FOV) to be scanned may be adjusted to a magnetic field center of an MRI system, and coordinate values in a coordinate system for shape-characteristic points of the FOV may be determined, where an origin of the coordinate system is located at the magnetic field center of the MRI system. A preset gradient magnetic field may be applied to the FOV, and coil units respectively covering the shape-characteristic points may be determined. An effective region may be obtained by connecting the determined coil units according to the shape of the FOV, and a coil unit located in the effective region may be determined as an effective coil unit for imaging the FOV by the MRI system.

Abstract: Impedance matching circuits and methods for radio frequency (RF) transmission coil are disclosed. An example impedance matching circuit includes a coil matching circuit, a RF power detection circuit, and a spectrometer. The spectrometer outputs an output voltage reversely applied on a varactor diode of the coil matching circuit. An impedance of the coil matching circuit is changed based on the output voltage. The spectrometer outputs a RF transmission signal to the RF power detection circuit, receives a power of a RF reflected signal corresponded to the output voltages. The spectrometer receives powers of different RF reflected signals corresponded to different output voltages, and assigns an output voltage corresponded to a minimum power of the RF reflected signals as an impedance matching voltage, where an equivalent impedance of the coil matching circuit and the RF transmission coil matches with an impedance of RF transmission lines.

Abstract: Methods, systems, and computer-readable storage mediums for correcting time in a nuclear magnetic resonance device are provided. In one aspect, a method includes obtaining respective transmission time delays of three gradient pulse signals that are generated by a three-dimensional gradient subsystem of the nuclear magnetic resonance device and include a slice-selection gradient signal, a phase-encoding gradient signal, and a frequency-encoding gradient signal, determining a time correction value according to the obtained respective transmission time delays of the three gradient pulse signals, and correcting a respective output time of each of the three gradient pulse signals, an output time of a radio-frequency (RF) pulse signal generated by a RF transmitting subsystem of the nuclear magnetic resonance device, and a reception time of a magnetic resonance signal received by a RF receiving subsystem in a scanning cycle according to the determined time correction value.

Abstract: A method for determining a position of an RF coil in a magnetic resonance imaging (MRI) system is disclosed. As an example, a center of a field of view (FOV) to be scanned may be adjusted to a magnetic field center of an MRI system, and coordinate values in a coordinate system for shape-characteristic points of the FOV may be determined, where an origin of the coordinate system is located at the magnetic field center of the MRI system. A preset gradient magnetic field may be applied to the FOV, and coil units respectively covering the shape-characteristic points may be determined. An effective region may be obtained by connecting the determined coil units according to the shape of the FOV, and a coil unit located in the effective region may be determined as an effective coil unit for imaging the FOV by the MRI system.

Abstract: A method of calibrating a RF power of a magnetic resonance imaging system is provided. With a fixed time-domain length of RF pulses, a RF pulse amplitude having a larger step size increment is selected to perform a traversal scanning to obtain FID signal values corresponding to different RF pulse amplitudes. In subsequent traversal scanning, the step size is continuously scaled down, and a start value and an end value are re-determined to continuously narrow a range for the subsequent traversal scanning, which may quickly and accurately determine a RF pulse amplitude corresponding to a 90° flip angle that can be obtained from a RF pulse amplitude corresponding to a maximum FID signal value in a last traversal scanning. A linear relationship between a flip angle and a RF pulse amplitude is obtained according to the 90° flip angle and its corresponding RF pulse amplitude for calibrating a RF power.

Abstract: A method for positioning a radio frequency (RF) receiver coil in a Magnetic Resonance Imaging (MRI) system is provided. In one example method, a distance from a center of the RF receiver coil to one end of a support bed for carrying a subject and a distance from one end of the support bed to an imaging center of the MRI system may be obtained after locations of the RF receiver coil, the subject, and the support bed may be fixed. A distance from the center of the RF receiver coil to the imaging center of the MRI system may be obtained based on the obtained two distances. Moving the support bed a displacement equal to the distance from the center of the RF receiver coil to the imaging center of the MRI system may enable centering of the RF receiver coil on the imaging center of the MRI system.

Abstract: Impedance matching circuits and methods for radio frequency (RF) transmission coil are disclosed. An example impedance matching circuit includes a coil matching circuit, a RF power detection circuit, and a spectrometer. The spectrometer outputs an output voltage reversely applied on a varactor diode of the coil matching circuit. An impedance of the coil matching circuit is changed based on the output voltage. The spectrometer outputs a RF transmission signal to the RF power detection circuit, receives a power of a RF reflected signal corresponded to the output voltages. The spectrometer receives powers of different RF reflected signals corresponded to different output voltages, and assigns an output voltage corresponded to a minimum power of the RF reflected signals as an impedance matching voltage, where an equivalent impedance of the coil matching circuit and the RF transmission coil matches with an impedance of RF transmission lines.