Enantioselective C-H amidation of sulfondiimines for the synthesis of 1,2,4-benzothiadiazine-1-imines under cobalt catalysis

In comparison to the notable recent progress in the derivatization of sulfoximines via directed C–H activation, the C–H activation/functionalization of sulfondiimines is underdeveloped. Here, we report C–H amidation/cyclization reactions of sulfondiimines with dioxazolones catalyzed by the combination of a cobalt(III) catalyst and a pseudo C₂-symmetric chiral carboxylic acid, leading to the formation of unprecedented 1,2,4-benzothiadiazine-1-imine structures in high enantioselectivity

Flaw-Tolerant Fracture Enabled by Liquid-like Elasticity in Liquid Crystal Elastomers

Polydomain liquid crystal elastomers (P-LCEs) with randomly oriented directors exhibit extraordinary in-plane liquid-like mechanical properties, attributed to the minimal energy cost of local nematic director rotation, distinguishing them from conventional elastomers. This study reveals that during tensile tearing, notched P-LCEs demonstrate exceptional strain homogenization across the specimen, effectively mitigating the crack-tip strain concentration and suppressing crack-tip opening over a broad range of applied stretching until the polydomain-to-monodomain transition threshold. This unique capability significantly delays macroscopic fracture. Compared with conventional elastomers, the reduction in fracture strain caused by notching is substantially smaller in P-LCEs, underscoring the critical role of strain homogenization in enhancing fracture resistance. Our findings contribute to a foundation for designing polymer-based soft materials with superior mechanical properties and fracture resistance

18世紀クンスト・メルヒェンにおける想像力論の実践と展開― ヴィーラント・ゲーテ・ノヴァーリスの三者を中心に ―

京都大学新制・課程博士博士(文学)甲第25726号文博第966号京都大学大学院文学研究科文献文化学専攻(主査)教授 川島 隆, 准教授 籠 碧, 准教授 杉山 卓史, 教授 松村 朋彦学位規則第4条第1項該当Doctor of LettersKyoto UniversityDGA

-Free Porphyrinoids

-Unsubstituted (-free) porphyrins have been an effective platform for creating versatile peripherally functionalized porphyrins and directly-linked porphyrin oligomers. The synthetic strategy has been extended to produce -free porphyrinoids including carbaporphyrins, core-modified porphyrins, ring-contracted, and ring-expanded porphyrins. -Free porphyrinoids can serve as a benchmark for demonstrating the inherent physical properties and stabilities, free from the influences of substituents, thereby highlighting the significance of these porphyrinoid classes

表面弾性波を用いたフォノン角運動量の研究

京都大学新制・課程博士博士(理学)甲第25833号理博第5144号京都大学大学院理学研究科化学専攻(主査)教授 小野 輝男, 教授 島川 祐一, 教授 堀毛 悟史学位規則第4条第1項該当Doctor of ScienceKyoto UniversityDGA

東日本における縄文時代後期の動物資源利用に関する研究―下総台地での事例―

京都大学新制・課程博士博士(人間・環境学)甲第26101号人博第1179号京都大学大学院人間・環境学研究科共生文明学専攻(主査)准教授 山崎 健, 教授 玉田 芳英, 准教授 脇谷 草一郎, 植月 学学位規則第4条第1項該当Doctor of Human and Environmental StudiesKyoto UniversityDFA

脊髄損傷後のマカクザルにおける運動野由来軸索投射の脊髄より高位での可塑性

京都大学新制・課程博士博士(医学)甲第25882号医博第5167号京都大学大学院医学研究科医学専攻(主査)教授 渡邉 大, 教授 林 康紀, 教授 荒川 芳輝学位規則第4条第1項該当Doctor of Medical ScienceKyoto UniversityDFA

Food Sharing among the Baka Hunter-Gatherers

京都大学新制・課程博士博士(地域研究)甲第26123号地博第342号京都大学大学院アジア・アフリカ地域研究研究科アフリカ地域研究専攻(主査)教授 安岡 宏和, 教授 高田 明, 教授 高橋 基樹, 教授 平野(野元) 美佐学位規則第4条第1項該当Doctor of Area StudiesKyoto UniversityDGA

Evolution of fatigue damage and dislocation structures in micron-sized nickel single crystals under low cyclic loading

In single crystal metals, the threshold for fatigue crack initiation generally exceeds the critical resolved shear stress (τCRSS) determined from unidirectional loading tests. In contrast, at the micron-scale, it has been reported that fatigue cracks initiate at stress amplitudes below the τCRSS, and this reversal phenomenon might be attributed to differences in testing methodologies employed in various research groups. In this study, tensile tests and tension-compression cyclic loading tests were performed on 2 μm-wide nickel (Ni) single crystals using the same experimental setup. The τCRSS obtained from the tensile tests was approximately 20 times higher than that of the bulk counterpart. During the initial stages of cyclic loading at a stress amplitude approximately half of the τCRSS, the dislocation density increased progressively with the number of cycles without accompanying macroscopic plastic deformation, indicating that τCRSS provides a threshold at which dislocations multiply rapidly over wide regions under unidirectional loading, and that dislocations move at lower stresses and can multiply under cyclic loading. Subsequently, localized slip and crack-like intrusion formed on the surface in association with development of self-organized ladder-like dislocation structures. This sequence of processes was comparable to the early stage of fatigue crack initiation observed in bulk Ni. Unlike bulk materials, ladder-like dislocation structures and intrusion/extrusion appeared without the formation of veins, which are stable self-organized dislocation structures. The findings of this study represent a significant advancement in our understanding of the fatigue behavior of micron-sized single crystal metals