@article{oai:repo.qst.go.jp:00081765,
 author = {Miyanishi, Koichiro and F. Segawa, Takuya and Takeda, Kazuyuki and Ohki, Izuru and Onoda, Shinobu and Ohshima, Takeshi and Abe, Hiroshi and Takashima, Hideaki and Takeuchi, Shigeki and I. Shames, Alexander and Morita, Kohki and Wang, Yu and Frederick, T.-K. So and Terada, Daiki and Igarashi, Ryuji and Kagawa, Akinori and Kitagawa, Masahiro and Mizuochi, Norikazu and Shirakawa, Masahiro and Negoro, Makoto and Izuru, Ohki and Shinobu, Onoda and Takeshi, Ohshima and Hiroshi, Abe and So, Frederick and Daiki, Terada and Ryuji, Igarashi and Masahiro, Shirakawa and Makoto, Negoro},
 issue = {1},
 journal = {Magnetic Resonance},
 month = {Jan},
 note = {We demonstrate room-temperature 13C hyperpolarization by dynamic nuclear polarization (DNP) using optically polarized triplet electron spins in two polycrystalline systems: pentacene-doped [carboxyl-13C] benzoic acid and microdia-monds containing NV−centers. For both samples, the integrated solid effect (ISE) is used to polarize the13C spin system in magnetic fields of 350-400 mT. In the benzoic acid sample, the13C spin polarization is enhanced up to 0.12% through directelectron-to-13C polarization transfer without performing dynamic1H polarization followed by 1H-13C cross polarization. In5addition, ISE has been successfully applied for the first time to polarize naturally abundant 13C spins in a microdiamond sample to 0.01%. To characterize the buildup of the13C polarization, we discuss the efficiencies of direct polarization transfer be-tween the electron and13C spins as well as that of13C–13C spin diffusion, examining various parameters which are beneficial or detrimental for successful bulk dynamic13C polarization.},
 pages = {33--48},
 title = {Room-temperature hyperpolarization of polycrystalline samples with optically polarized triplet electrons: pentacene or nitrogen-vacancy center in diamond?},
 volume = {2},
 year = {2021}
}