Design and Implementation of NMR Permanent Magnet Precision Temperature Controller

doi:10.11938/cjmr20182632

Abstract

Abstract: Neodymium-iron-boron (NdFeB) permanent magnets always used to generate a static magnetic field in low field NMR spectrometers has poor temperature stability. Temperature fluctuations will affect the reliability of NMR experiments. In order to improve the stability of low-field magnetic resonance spectrometer, a precise temperature control scheme of permanent magnet based on dual-loop control algorithm was proposed and verified on 0.06 T NMR spectrometer. The results show that the 24 h temperature control accuracy is better than ±0.005℃. And the drift in ¹H resonance frequency decreases from 255 Hz to 15 Hz within 0.5 h, and from 4 950 Hz to 145 Hz within 24 h, compared to that without temperature control. That improves the stability of low-field NMR spectrometer with permanent magnet effectively.

Key words: low-field NMR, precision temperature controller, double-loop control algorithm, permanent magnet

CLC Number:

O482.53

YANG Chang, CHEN Jun-fei, CHEN Li, ZHANG Zhi, FENG Ji-wen, CHEN Fang, LIU Chao-yang. Design and Implementation of NMR Permanent Magnet Precision Temperature Controller[J]. Chinese Journal of Magnetic Resonance, 2018, 35(3): 294-302.

References

[1] ZHANG Y, BLÜMICH B. Gint2D-T₂ correlation NMR of porous media[J]. J Magn Reson, 2015, 252:176-186.
[2] ZHANG Y, XIAO L Z, LIAO G Z, et al. Direct correlation of diffusion and pore size distributions with low field NMR[J]. J Magn Reson, 2016, 269:196-202.
[3] LIU H B, NOGUEIRA D E M, OBRUCHKOV S, et al. Determining pore length scales and pore surface relaxivity of rock cores by internal magnetic fields modulation at 2MHz NMR[J]. J Magn Reson, 2014, 246:110-118.
[4] MITCHELL J. Rapid measurements of heterogeneity in sandstones using low-field nuclear magnetic resonance[J]. J Magn Reson, 2014, 240:52-60.
[5] LEWIS R T, DJURHUUS K, SELAND J G. Characterising oil and water in porous media using decay due to diffusion in the internal field[J]. J Magn Reson, 2015, 259:1-9.
[6] 陈海玲. 钕铁硼永磁材料热稳定性快速检测方法的研究[D]. 沈阳:沈阳工业大学, 2005.
[7] 胡志华. 烧结Nd-Fe-B磁体的磁性能、温度稳定性以及冲击韧性研究[D]. 沈阳:东北大学, 2009.
[8] KIM S H, DOOSE C. Temperature compensation of NdFeB permanent magnets[C]//IEEE:Particle Accelerator Conference, 1998, 3:3227-3229.
[9] YAO B L, LIN Y, LIU X Q. Analysis of thermal performance of NdFeB permanent magnet[J]. Electric Machines & Control Application, 2008, 35(4):52-55. 姚丙雷, 林岩, 刘秀芹. 钕铁硼永磁材料热性能的分析[J]. 电机与控制应用, 2008, 35(4):52-55.
[10] 利格斯迈尔著, 张聚译. 嵌入式系统软件工程-基础知识, 方法和应用[M]. 北京:电子工业出版社, 2009.
[11] 乔治·埃利斯著, 汤晓君译. 控制系统设计指南[M]. 北京:机械工业出版社, 2016.
[12] HE Y G, FENG J W, ZHANG Z, et al. A peripheral component interconnect express-based scalable and highly integrated pulsed spectrometer for solution state dynamic nuclear polarization[J]. Rev Sci Instrum, 2015, 86(8):083101.

[1]	LIU Zhuo, OU-YANG Chuan-xiang, WANG Chang-quan, HAN Deng-lin, WU Qiong, GAO Xing. Construct NMR Capillary Pressure Curves by Piecewise Power Function Based on T₂ Cutoff Values [J]. Chinese Journal of Magnetic Resonance, 2019, 36(1): 45-54.
[2]	CHANG Xiao, SU Guan-qun, NIE Sheng-dong. Wavelet Transform-Based Signal Denoising in Low-Field NMR [J]. Chinese Journal of Magnetic Resonance, 2018, 35(3): 393-406.
[3]	ZOU Yue-qi, GUO Pan, XU Zheng. High-Efficiency Low-Field Nuclear Magnetic Resonance Measurements with a Monte Carlo Simulation Algorithm [J]. Chinese Journal of Magnetic Resonance, 2018, 35(2): 226-233.
[4]	ZHANG Shi-mao, ZHANG Shao-nan, GE Xiang, WU Jian-meng. Optimal Design and Application of Two-Dimensional NMR Logging in Chuanxi Tight Gas Reservoir [J]. Chinese Journal of Magnetic Resonance, 2018, 35(2): 234-242.
[5]	LIU Zhong-chun, CHENG Qian, LIU Nai-gui, ZHOU Yang, FANG Tao, ZHU Tao-tao, WANG Wei-min. NMR On-Line Measurement of Stress Sensitivity of Tight Matrix Limestone Cores in a Karstic Reservoir [J]. Chinese Journal of Magnetic Resonance, 2017, 34(2): 206-213.
[6]	DENG Feng, XIAO Li-zhi, TAO Ye, LIU Xin-yun, GENG Dong-shi, WANG Meng-ying. Low-Field and On-Line NMR Detection for Fluid Molecular Structure [J]. Chinese Journal of Magnetic Resonance, 2017, 34(2): 214-222.
[7]	LIU Ying, ZHANG Yu-wen, LIANG Zhen, ZHANG Hao-wei. A Heterogeneous Dual-Core Receiver System for Magnetic Resonance Applications [J]. Chinese Journal of Magnetic Resonance, 2017, 34(1): 100-107.
[8]	DENG Feng, XIAO Li-zhi, TAO Ye, GENG Dong-shi, WANG Meng-ying. Low-Field NMR Flowing Fluid Measurement: The Effects of Flow Rate and Corrections [J]. Chinese Journal of Magnetic Resonance, 2017, 34(1): 78-86.
[9]	CHEN Shan-shan, XIA Tian, BI Xin, MIAO Zhi-ying, YANG Pei-qiang, WANG Hong-zhi, DAI Shu-guang. Design and Implementation of An Active Shimming System for Low Field NMR Analyzers [J]. Chinese Journal of Magnetic Resonance, 2017, 34(1): 87-99.
[10]	LIU Min，QIU Wen-qi，SUN Hui-jun*，CHEN Zhong. Progress in the Portable NMR Spectrometer [J]. Chinese Journal of Magnetic Resonance, 2014, 31(4): 504-514.
[11]	ZHAO Shou-yuan1，WANG Yuan-yuan1，ZHANG Rong-chun2，CHEN Tie-hong1，SUN Ping-chuan1*?. Low-Field NMR Studies on the Structure and Dynamics of Nanocomposite Hydrogels [J]. Chinese Journal of Magnetic Resonance, 2014, 31(2): 172-184.
[12]	NIU Qiang1,2，WANG Zhi-zhan3，ZENG Jian-hui1，WANG Xin2，DU Huan-fu2，GAI Shan-shan2*. Evaluating Shale Porosity and Oil Content with 2D NMR [J]. Chinese Journal of Magnetic Resonance, 2014, 31(2): 206-213.
[13]	HOU Shu-Lian, XIE Huan-Tong, HOU Xiao-Wen, LI Shi-Yu, CHEN Wei. Gradient Coil of Permanent Magnet Mini-Magnetic Resonance Imager and Image Quality [J]. Chinese Journal of Magnetic Resonance, 2012, 29(4): 508-520.
[14]	SUN Wei, WANG Wei-Min, GU Chang-Chun, ZHANG Yan-Lei. DESIGN OF A MAGNET USED IN A PORTABLE NMR ROCK ANALYZER [J]. Chinese Journal of Magnetic Resonance, 2004, 21(3): 337-344.