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High-density highly oriented graphite sheets provided by Kaneka Corporation have been applied as stripper disks for heavy-ion acceleration at RIKEN RI Beam Factory since 2014. The graphite sheets withstand increasing amounts of beam intensity. We observed the graphite sheets after beam irradiation with an electron microscope and their lifetime was discussed.

The photolyses of dibenzothiophene N-substituted sulfilimines was performed in the presence of several trapping reagents such as sulfides, olefins, and phosphorus compounds to evaluate their ability as photochemical nitrene sources. The potent nature of dibenzothiophene N-tosyl and N-acylsulfilimines as nitrogen sources are indicated by the good yield of sulfilimines, aziridines, and iminophosphoranes.

The total synthesis of ciguatoxin and 51-hydroxyCTX3C, the two most toxic members of the ciguatoxin family, which is the principal cause for ciguatera seafood poisoning, is described. The synthesis, effected from the corresponding left and right wing fragments in a minimum number of steps, is based on a second generation strategy combined with a stereo- and chemoselective radical cyclization process.

The key transformations in the synthesis of the right wings of ciguatoxins are presented. These syntheses improved the stereoselectivity and efficiency in comparison to a previous synthesis.

Using a newly developed edge-support heat treatment method of polyimide, self-standing graphite thin films (GTFs) with a frame were prepared. The graphite basal plane in the GTF was oriented in the direction of the film surface, resulting in GTFs with high quality, large area, and a uniform thickness of 50–120 nm. The thickness distribution (3σ) with an area of 25 mm × 25 mm and a thickness of 54 nm sample was 5.17 nm (measurement area 7.8 mm × 10.4 mm). The electric conductivity of a similarly prepared sample was 1.81 × 104 S/cm. The Young's modulus and ultimate tensile strength of a 60-nm-thick GTF were 1.02 × 102 and 5.34 GPa, respectively. Approximately 50 nm thick GTF samples were thinned by reactive ion etching using oxygen to fabricate a thickness between 10 and 20 nm. A film with an area of 10 mm × 10 mm and thickness of 16.7 nm exhibited a 3σ value of 1.80 nm which means that the thickness difference corresponds to 5 layers of graphite. The conductivity of a 16.2-nm-thick GTF was 1.79 × 104 S/cm. These results indicate that the etching proceeded uniformly. The proposed top-down method is an industrially superior method that overcomes the drawbacks of conventional bottom-up methods. Using a modified ES method of polymer HT and its combination with RIE, crystalline GTFs at a thickness of 10–120 nm with an area within the cm scale were successfully fabricated. The GTF was fabricated with no substrate and exhibited good crystallinity, excellent thickness uniformity at the ±10% level, no wrinkles, and higher Young's modulus and UTS. Photograph of the produced GTF with 16.7 nm thick (a) and 25 × 25 mm2 area. and with 10.7 nm thick and 10 × 10 mm2 area (b). [Display omitted] [ABSTRACT FROM AUTHOR]