[1] Nanni E A, Barnes A B, Griffin R G, et al. THz dynamic nuclear polarization NMR[J]. IEEE Transactions onTerahertz Science and Technology, 1, 145-163(2011).

[2] Griffin R G, Prisner T F. High field dynamic nuclear polarization—the renaissance[J]. Physical Chemistry Chemical Physics, 12, 5737-5740(2010).

[3] Masion A, Alexandre A, Ziarelli F, et al. Dynamic Nuclear Polarization NMR as a new tool to investigate the nature of organic compounds occluded in plant silica particles[J]. Scientific Reports, 7, 3430(2017).

[4] Liao S Y, Lee M, Wang T, et al. Efficient DNP NMR of membrane proteins: sample preparation protocols, sensitivity, and radical location[J]. Journal of Biomolecular NMR, 64, 223-237(2016).

[5] Leggett J, Hunter R, Granwehr J, et al. A dedicated spectrometer for dissolution DNPNMR spectroscopy[J]. Physical Chemistry Chemical Physics, 12, 5883-5892(2010).

[6] Plainchont B, Berruyer P, Dumez J N, et al. Dynamic nuclear polarization opens new perspectives for NMR spectroscopy in analytical chemistry[J]. Analytical Chemistry, 90, 3639-3650(2018).

[7] Mompeán M, Sánchez-Donoso R M, De LaHoz A, et al. Pushing nuclear magnetic resonance sensitivity limits with microfluidics and photo-chemically induced dynamic nuclear polarization[J]. Nature Communications, 9, 108(2018).

[13] Temkin R J. Development of terahertz gyrotrons for spectroscopy at MIT[J]. Terahertz Science and Technology, 7, 1-9(2014).

[14] [14] Hnstein M K, Bajaj V S, Griffin R G, et al. Design of a 460 GHz second harmonic gyrotron oscillat f use in dynamic nuclear polarization[C]Proceedings of the Twenty Seventh International Conference on Infrared Millimeter Waves. San Diego: IEEE, 2002: 193194.

[15] Idehara T, Kosuga K, Agusu L, et al. Continuously frequency tunable high power sub-THz radiation source—gyrotron FU CW VI for 600 MHz DNP-NMR spectroscopy[J]. Journal ofInfrared, Millimeter, and Terahertz Waves, 31, 775-790(2010).

[16] Glyavin M Y, Chirkov A V, Denisov G G, et al. Experimental tests of a 263 GHz gyrotron for spectroscopic applications and diagnostics of various media[J]. Review ofScientific Instruments, 86, 054705(2015).

[17] Yoon D, Soundararajan M, Cuanillon P, et al. Dynamic nuclear polarization by frequency modulation of a tunable gyrotron of 260 GHz[J]. Journal of Magnetic Resonance, 262, 62-67(2016).

[18] [18] Braunmüller F. Gyrotron physics from linear to chaotic regimes: experiment numerical modeling[D]. Lausanne: École Polytechnique Fédérale de Lausanne, 2016: 5076.

[19] Airila M I, Dumbrajs O, Reinfelds A, et al. Nonstationary oscillations in gyrotrons[J]. Physicsof Plasmas, 8, 4608-4612(2001).

[20] [20] Kern S. Numerische simulation der gyrotronwechselwirkung in koaxialen resonaten[D]. Karlsruhe: Universität Karlsruhe, 1996.

[21] [21] Kartikeyan M V, Bie E, Thumm M K A. Gyrotrons— high power microwave millimeter wave technology[M]. Berlin: Springer Press, 2003.

[22] Dumbrajs O, Nusinovich G S. Self-consistent non-stationary theory of the gyrotron[J]. Physics of Plasmas, 23, 083125(2016).

[23] Li Zhengdi, Du Chaohai, Qi Xiangbo, et al. A 0.33-THz second-harmonic frequency-tunable gyrotron[J]. Chinese Physics B, 25, 029401(2016).

[24] Zhao Qixiang, Yu Sheng, Zhang Yanyan, et al. Investigation of the influence of electron beam quality on the operation in 0.42-THz second harmonic gyrotron[J]. IEEE Transactions on Plasma Science, 44, 749-754(2016).

[25] [25] Zhang Yanqing. Research on magron injected gun of a ultrawideb continuously adjustable terahertz gyrotron[D]. Chengdu: University of Electronic Science Technology of China, 2020