Gradient shimming method for overcoming convection effect on nuclear magnetic resonance spectrometer
A technology of nuclear magnetic resonance spectroscopy and gradient shimming, which can be used in magnetic resonance measurement, measurement of magnetic variables, etc., and can solve problems such as decreased effect.
Active Publication Date: 2013-10-09
XIAMEN UNIV
View PDF7 Cites 8 Cited by
- Summary
- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
Problems solved by technology
One problem that the above gradient shimming method does not solve is that for common samples such as acetone and chloroform, although the signal-to-noise ratio and speed of proton gradient shimming are better than deuterium gradient shimming, on some samples (especially Chloroform and acetone (two commonly used solvents) the effect of one-dimensional and three-dimensional gradient shimming of hydrogen nuclei will decrease
Method used
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View moreImage
Smart Image Click on the blue labels to locate them in the text.
Smart ImageViewing Examples
Examples
Experimental program
Comparison scheme
Effect test
Embodiment Construction
[0019] The superconducting nuclear magnetic resonance spectrometer is generally equipped with a temperature-controlled gas circuit for adjusting the experimental temperature of the sample to be tested. The convective effect is mainly caused by the temperature difference above and below the sample caused by the temperature-controlled air flow. The implementation process can use a pulse sequence including a gradient module that compensates for convection, or a method of adjusting the temperature-controlled airflow to reduce the temperature difference inside the sample to overcome the decline in gradient shimming effect caused by the convection effect.
[0020] For gradient shimming, the field diagram of the shimming coil must be prepared in advance. Sampling on the NMR spectrometer to prepare the shim coil field diagram should also pay attention to avoid the influence of the convection effect. Mixed samples of water and heavy water are commonly used, and samples with low viscous...
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More PUM
Login to View More Abstract
The invention provides a gradient shimming method for overcoming the convection effect on a nuclear magnetic resonance spectrometer, and relates to the nuclear magnetic resonance spectrometer. The gradient shimming method for overcoming the convection effect on the nuclear magnetic resonance spectrometer can overcome the convection effect inside a sample. The gradient shimming method comprises the following steps: step 1, a field graph of a shim coil is prepared in advance; step 2, the impulse sequence of a gradient module which comprises compensation convection in the direction of frequency coding is used, or the impulse sequence of a gradient shimming is used, but the temperature difference inside the sample is reduced; step 3, the impulse sequence is used for conducting two times of imaging sampling, sampling data are obtained, after the data are processed, the electric current variation of the shim coil which needs modulation is calculated through fitting, and hardware is led in; step 4, shimming iteration convergence condition judgment is conducted, and the step 3 and the step 4 are repeated if the convergence is not conducted. According to the gradient shimming method for overcoming the convection effect on the nuclear magnetic resonance spectrometer, the gradient module which comprises the compensation convection in the direction of frequency coding is used in the impulse sequence, or temperature control airflow is adjusted at the time of the gradient shimming so as to reduce the temperature difference inside the tested sample as much as possible, and therefore the effect of the convection effect on the gradient shimming is compensated or reduced.
Description
technical field [0001] The invention relates to a nuclear magnetic resonance spectrometer, in particular to a gradient shimming method for overcoming the convection effect on the nuclear magnetic resonance spectrometer. Background technique [0002] A high degree of uniformity in the magnetic field is a prerequisite for conventional NMR spectroscopy. On the high-resolution NMR spectrometer, dozens of groups of shim coils provide additional magnetic fields to compensate the inhomogeneous magnetic field inside the sample to meet the detection requirements of high uniformity. It is a very time-consuming process to manually adjust the current of these shim coils to make the magnetic field reach the uniformity required for detection. At present, the most effective automatic shimming method in NMR technology is gradient shimming, which uses magnetic resonance imaging to measure the magnetic field distribution of each shimming coil, and also measures the uneven distribution of the...
Claims
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More Application Information
Patent Timeline
Login to View More IPC IPC(8): G01R33/38G01R33/44
Inventor 刘光曹陈忠蔡淑惠
Owner XIAMEN UNIV