Jilin University

Tingting Lin

Ling Wan

Yang Zhang

Jun Lin

Kun Zhou

Jing Zhao

Xing Gao

Yujing Yang

Chao Chen

Xin Cai

Ying Yang

Hongyu Wang

Zekai Liu

Xu Shu

Weihao Yang

Yue Li

Hualiang Wang

Pengfei Wang

Qi Yu

Yu Song

A high-efficiency and high signal-to-noise ratio surface nuclear magnetic resonance detection method is provided. The present disclosure adopts a concentric arrangement of a direct current transmitting coil and an alternating current transmitting coil to form a transmitting coil group, replacing the traditional single alternating current transmitting coil. Through the change of magnetization intensity caused by alternating excitation, the direct current emission time, alternating current emission time and emission interval time are adjusted, and the magnetization intensity is controlled to be gradually accumulated and stabilized in a certain range, thus improving the macro magnetization vector of hydrogen atoms. The single pulse emission time of the alternating excitation emission mode provided by the present disclosure is within 1 second, which can effectively improve the detection efficiency. The present disclosure achieves the effect of simultaneously improving the signal-to-noise ratio of surface nuclear magnetic resonance detection signals and enhancing detection efficiency.

High-efficiency and high signal-to-noise ratio surface nuclear magnetic resonance detection method

An adaptive gain transient electromagnetic receiving system based on exponential prediction and a method thereof are provided. The system includes a signal input unit, an amplification unit, a gain control unit, and a dual channel signal acquisition card. The signal input unit includes a receiving coil and a low-pass filter, and the amplification unit is a voltage controlled amplifier; the low-pass filter pre-processes the output signal of the receiving coil and divides the output signal into two signals. One is passed through a gain control unit, and the other enters into a voltage controlled amplifier. The A/D converter of the gain control unit converts the analog signal output by the low-pass filter into a digital signal, the FPGA module calculates the gain voltage, and the dual channel signal acquisition card collects the amplified signal and gain voltage simultaneously, which enhances the signal detection capability in deep regions.

Adaptive gain transient electromagnetic receiving system based on exponential prediction and method thereof

A distributed device and method for detecting groundwater based on nuclear magnetic resonance are provided. The device includes an excitation apparatus, multiple polarization apparatuses, an aerial reception apparatus, and a control apparatus. The aerial reception apparatus includes an array cooled coil sensor. For each of the multiple polarization apparatuses, a position analysis module determines, together with a second position analysis module of the polarization apparatus, a position of the array cooled coil sensor relative to a polarization coil in the polarization apparatus. A polarization transmitter in the polarization apparatus switches to a mode of waiting for output in a case that the array cooled coil sensor is in coverage of the polarization coil. The polarization transmitter in the polarization apparatus remains in a standby mode in a case that the array cooled coil sensor is beyond coverage of the polarization coil.

Distributed device and method for detecting groundwater based on nuclear magnetic resonance

The instant invention relates to a method for noise reduction from a magnetic resonance sounding (MRS) oscillating signal, and more particularly, to a data processing method for reducing random noise contained in MRS oscillating signal based on joint algorithm principles of EMD and TFPF. A MRS oscillating signal is decomposed into different eigen-mode components by using decomposition characteristic of EMD algorithm; then a signal-dominated eigen-mode component is encoded as an instantaneous frequency of an analytical signal of unit amplitude using TFPF algorithm; and random noise is suppressed with the characteristics that the time-frequency distribution of the analytical signal is concentrated along with the instantaneous frequency. The method requires fewer filtering constraints and is simple to operate without need of designing a filtering interval in the time-frequency domain, and has good adaptability to the MRS oscillating signal with a low signal-noise-ratio.

Method for random noise reduction from MRS oscillating signal using joint algorithms of EMD and TFPF

An anti-saturation device for a ground magnetic resonance signal amplifying circuit has a receiving coil connected with a band-pass filter circuit through a pre-amplifying circuit and a programmable amplifying circuit. The programmable amplifying circuit is connected with an AD acquisition card through the band-pass filter circuit. The band-pass filtering circuit is connected with a computer through the AD acquisition card, and the AD acquisition card is connected with an emitting system through the computer. An automatic amplification factor adjusting module is embedded into a nuclear magnetic resonance detector, and can also directly replace a receiving amplification circuit of the nuclear magnetic resonance detector to work independently.

Anti-saturation device and method for ground magnetic resonance signal amplifying circuit

Provided are a surface nuclear magnetic resonance system excited by a geoelectric field and a field working method for groundwater detection. A computer is connected to a synchronization module via a transmitter. The transmitter is connected to a first electrode and a second electrode via a transmission line. Receiving coils are symmetrically arranged on two sides of the transmission line. Each of the receivers is mounted with two receiving coils. The computer is connected to a fourth receiver via a first receiver, a second receiver, a third receiver, a sixth receiver and a fifth receiver, and the synchronization module is connected to the first receiver, the second receiver, the third receiver, the fourth receiver, the fifth receiver and the sixth receiver.

Surface nuclear magnetic resonance system excited by geoelectric field for groundwater detection and field detection method

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Changchun, China

Tingting Lin