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您的检索式：作者名="Shintaro Azuma"
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| 1 | Initiation of plate tectonics in the Hadean: Eclogitization triggered by the ABEL Bombardment显示文摘When plate tectonics began on the Earth has been long debated and here we argue this topic based on the records of Earth-Moon geology and asteroid belt to conclude that the onset of plate tectonics was during the middle Hadean(4.37-4.20 Ga). The trigger of the initiation of plate tectonics is the ABEL Bombardment, which delivered oceanic and atmospheric components on a completely dry reductive Earth, originally comprised of enstatite chondrite-like materials. Through the accretion of volatiles, shock metamorphism processed with vaporization of both CI chondrite and supracrustal rocks at the bombarded location, and significant recrystallization went through under wet conditions, caused considerable eclogitization in the primordial continents composed of felsic upper crust of 21 km thick anorthosite, and 50 km or even thicker KREEP lower crust. Eclogitization must have yielded a powerful slab-pull force to initiate plate tectonics in the middle Hadean. Another important factor is the size of the bombardment. By creating Pacific Ocean class crater by 1000 km across impactor, rigid plate operating stagnant lid tectonics since the early Hadean was severely destroyed, and oceanic lithosphere was generated to have bi-modal lithosphere on the Earth to enable the operation of plate tectonics.Considering the importance of the ABEL Bombardment event which initiated plate tectonics including the appearance of ocean and atmosphere, we propose that the Hadean Eon can be subdivided into three periods:(1) early Hadean(4.57-4.37 Ga),(2) middle Hadean(4.37-4.20 Ga), and(3) late Hadean(4.20-4.00 Ga). | Shigenori Maruyama M.Santosh Shintaro Azuma | 2018 | Geoscience Frontiers2018，9，4： | 8 |
| 2 | Molecules with a TEMPO-based head group as high-performance organic friction modifiers显示文摘High-performance organic friction modifiers(OFMs)added to lubricating oils are crucial for reducing energy loss and carbon footprint.To establish a new class of OFMs,we measured the friction and wear properties of N-(2,2,6,6-tetramethyl-1-oxyl-4-piperidinyl)dodecaneamide referred to as C12Amide-TEMPO.The effect of its head group chemistry,which is characterized by a rigid six-membered ring sandwiched by an amide group and a terminal free oxygen radical,was also investigated with both experiments and quantum mechanical(QM)calculations.The measurement results show that C12Amide-TEMPO outperforms the conventional OFMs of glyceryl monooleate(GMO)and stearic acid,particularly for load-carrying capacity,wear reduction,and stability of friction over time.The friction and wear reduction effect of C12Amide-TEMPO is also greatly superior to those of C12Ester-TEMPO and C12Amino-TEMPO,in which ester and amino groups replace the amide group,highlighting the critical role of the amide group.The QM calculation results suggest that,in contrast to C12Ester-TEMPO,C12Amino-TEMPO,and the conventional OFMs of GMO and stearic acid,C12Amide-TEMPO can form effective boundary films on iron oxide surfaces with a unique double-layer structure:a strong surface adsorption layer owing to the chemical interactions of the amide oxygen and free radical with iron oxide surfaces,and an upper layer owing to the interlayer hydrogen-bonding between the amide hydrogen and free radical or between the amide hydrogen and oxygen.Moreover,the intralayer hydrogen-bonding in each of the two layers is also possible.We suggest that in addition to strong surface adsorption,the interlayer and intralayer hydrogen-bonding also increases the strength of the boundary films by enhancing the cohesion strength,thereby resulting in the high tribological performance of C12Amide-TEMPO.The findings in this study are expected to provide new hints for the optimal molecular design of OFMs. | Jinchi HOU Masaki TSUKAMOTO Seanghai HOR Xingyu CHEN Juntao YANG Hedong ZHANG Nobuaki KOGA Koji YASUDA Kenji FUKUZAWA Shintaro ITOH Naoki AZUMA | 2023 | Friction2023，11，2： | 0 |
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