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When the quenching occurs in a superconducting coil, excessive joule heating in normal area may damage the coil. It is necessary to detect quenching in the coil as soon as possible and discharge the magnetic energy stored in the coil. Therefore, we propose a superconducting coil protection system based on an active power method. The system is highly resistant to the noise and does not require cancel voltage taps, so it is useful for both AC and DC coils. We have presented the effectiveness of the system using some test coils cooled in LN 2 or LHe. However, we have not discussed the effectiveness of the proposed system for helium-free cryocooled magnets, in which a larger temperature rise occurs after quenching than in liquid-cooled magnets. In this paper, we verify the effectiveness and practicality of the proposed system through coil protection tests for a cryocooled Nb 3 Al LTS coil.

During studies for identification of biologically active components from natural sources, a new polyoxygenated xanthone mangostanol was isolated from the fruit hull of Garcinia mangostana , along with known xanthones, α-mangostin, γ-mangostin, gartanin, 8-deoxygartnin, 5,9-dihydroxy-2,2-dimethyl-8-methoxy-7-(3-methylbut-2-enyl)-2 H ,6 H -pyrano[3,2- b ]xanthen-6-one, garcinone E and 2-(γ,γ-dimethylallyl)-1,7-dihydroxy-3-methoxyxanthone and epicatechin. Spectroscopic analysis mainly by 1D and 2D NMR spectroscopy, established the structure of mangostanol {3,5,9-trihydroxy-2,2-dimethyl-8-methoxy-7-(3-methylbut-2-enyl)-2 H ,6 H -3,4-dihydropyrano[3,2- b ]xanthen-6-one} Mangostanol, and α- and γ-mangostin show moderate inhibitory effects on cAMP phosphodiesterase.