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2,2′-Biazulene diimide-based conjugate polymers for highperformance field-effect transistors

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Science China Chemistry 2018年第8期61卷 973-974页

作者： taku Shoji Shunji Ito Graduate School of Science and Technology Shinshu University Graduate School of Science and Technology Hirosaki University

Azulene,which is one of the non-alternating 10π-electron aromatic compounds,has attracted the interest of many research groups due to the application to material sciences utilizing the unique optoelectronic properties.

关键词： Th THF Biazulene diimide-based conjugate polymers for highperformance field-effect transistors PTB

Phase transition in Pd_(40)Ni_(10)Cu_(30)P_(20) bulk metallic glass under HP & HT

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Science China(Physics,Mechanics & Astronomy) 2005年第6期48卷 716-722页

作者： Utsumi Wataru Okada taku Synchrotron Radiation Research Center Japan Atomic Energy Research Institute 1-1-1 Kout Mikasuki Sayo Hyogo 679-5148 Japan

The phase transitions in Pd40Ni10Cu30P20 bulk metallic glass (BMG) have been studied under high pressure and high temperature (HP & HT) by X-ray diffraction measurements with synchrotron radiation source. We found that the BMG underwent a phase transitions of amorphous-crystalline-amorphous at 10 GPa upon heating. The parallel experiments were carried out at 7 GPa, while we did not observe the amorphous-crystalline-amorphous transitions by increasing temperature. Quenching the melted BMG at 7 GPa, it was found that the phase crystallized from the melt differed from the primary phase crystallized from the starting amorphous solid upon heating, suggesting there existed a distinct mechanism in two cases.

关键词： phase transition, Pd40Ni10Cu30P20, high pressure and high temperature.

Ab Initio Two-Phase Molecular Dynamics on the Melting Curve of SiO_2

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Journal of Earth Science 2010年第5期21卷 801-810页

作者： Yusuke Usui taku Tsuchiya Geodynamics Research Center Ehime University

Ab initio two-phase molecular dynamics simulations were performed on silica at pressures of 20-160 GPa and temperatures of 2 500-6 000 K to examine its solid-liquid phase boundary. Results indicate a melting temperature （Tin） of 5 900 K at 135 GPa. This is 1 100 K higher than the temperature considered for the core-mantle boundary （CMB） of about 3 800 K. The calculated melting temperature is fairly consistent with classical MD （molecular dynamics） simulations. For liquid silica, the O-O coordination number is found to be 12 along the Tm and is almost unchanged with increasing pressure. The self-diffusion coefficients of O and Si atoms are determined to be 1.3×10^-9-3.3×10^-9 m2/s, and the viscosity is 0.02-0.03 Pa＇s along the Tin. We find that these transport properties depend less on pressure in the wide range up of more than 135 GPa. The eutectic temperatures in the MgO-SiO2 systems were evaluated and found to be 700 K higher than the CMB temperature, though they would decrease considerably in more realistic mantle compositions.

关键词： Ab Initio Two-Phase Molecular Dynamics on the Melting Curve of SiO2 SiO CMB MgO than

Base flow separation for soil erosion simulation in a granitic forested headwater catchment using a process-based model, GeoWEPP

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International Journal of Sediment Research 2023年第4期38卷 494-502页

作者： takuhei Yamasaki Shoichiro Hamamoto taku Nishimura The Graduate School of Agricultural and Life Sciences The University of Tokyo

Distributed erosion models, which simulate the physical processes of water flow and soil erosion, are effective for predicting soil erosion in forested catchments. Although subsurface flow through multiple pathways is dominant for runoff generation in forested headwater catchments, the process-based erosion model, Geo-spatial interface for Water Erosion Prediction Project(Geo WEPP), does not have an adequate subsurface component for the simulation of hillslope water flow. In the current study, the quick flow related to soil erosion during rainfall events is separated from the total hydrograph using base flow separation for Geo WEPP to use direct runoff to predict sediment discharge from a granitic-forested catchment in Japan. Water runoff and sediment discharge also are simulated using the conventional method that reproduces the total hydrograph, and the accuracy of the calculation and estimated erodibility parameters are evaluated. The proposed procedure reproduced the quick-flow runoff during rainfall and the cumulative sediment discharge from the catchment. Simultaneously, the proposed procedure overestimates water runoff during extreme weather events, such as typhoons. The estimated erodibility parameters for the hillslope soil were comparable to those of the surface soil in Japan using both the proposed procedure and the conventional one. Conversely, the channel erodibility obtained from the proposed procedure matched the observed sediment characteristics in the granitic forested catchment. The proposed procedure is a promising method to predict sediment discharge from forested catchments based on the geological features of the catchment.

关键词： Soil erosion Base flow separation GeoWEPP Headwater catchment Forest

Expanding-contracting Earth

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Geoscience Frontiers 2013年第3期4卷 341-347页

作者： taku Tsuchiya Kenji Kawai Shigenori Maruyama Geodynamic Research Center Ehime UniversityMatsuyamaEhime 790-8577Japan Department of Earth and Planetary Sciences Tokyo Institute of TechnologyMeguroTokyo 152-8551Japan Department of Earth Science University of CaliforniaSanta Barbara 93106CAUSA

The Earth was born from a giant impact at 4.56 Ga. It is generally thought that the Earth subsequently cooled, and hence shrunk, over geologic time. However, if the Earth＇s convection was double-layered, there must have been a peak of expansion during uni-directional cooling. We computed the expansion- contraction effect using first principles mineral physics data. The result shows a radius about 120 km larger than that of the present Earth immediately after the consolidation of the magma-ocean on the surface, and subsequent shrinkage of about 110 km in radius within about 10 m.y., followed by gradual expansion of 11 km in radius due to radiogenic heating in the lower mantle in spite of cooling in the upper mantle in the Archean. This was due to double-layered convection in the Archean with final collapse of overturn with contraction of about g km in radius, presumably by the end of the Archean. Since then, the Earth has gradually cooled down to reduce its radius by around 12 km. Geologic evidence supports the late Archean mantle overturn ca. 2.6 Ga, such as the global distribution of super-liqnidus flood basalts on nearly all cratonic fragments （〉35 examples）. If our inference is correct, the surface environment of the Earth must have undergone extensive volcanism and emergence of local landmasses, because of the thin ocean cover （3-5 km thickness）. Global unconformity appeared in cratonic fragments with stromatolite back to 2.9 Ga with a peak at 2.6 Ga. The global magmatism brought extensive crustal melting to yield explosive felsic volcanism to transport volcanic ash into the stratosphere during the catastrophic mantle overturn. This event seems to be recorded by sulfur mass-independent fractionation （SMIF） at 2.6 Ga. During the mantle overturn, a number of mantle plumes penetrated into the upper mantle and caused local upward doming of by ca. 2-3 km which raised local landmasses above sea-level. The consequent increase of atmospheric oxygen enabled life evolutio

关键词： Mantle overturn Expanding Earth Global unconformity Nutrients Eukaryotes

The second continent:Existence of granitic continental materials around the bottom of the mantle transition zone

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Geoscience Frontiers 2013年第1期4卷 1-6页

作者： Kenji Kawai Shinji Yamamoto taku Tsuchiya Shigenori Maruyama Department of Earth Science University of CaliforniaSanta BarbaraCA 93106USA Department of Earth and Planetary Sciences Tokyo Institute of TechnologyOokayama 2-12-1MeguroTokyo 152-8551Japan Department of Earth and Planetary Sciences Tokyo Institute of TechnologyOokayama 2-12-1MeguroTokyo 152-8551.Japan Department of Earth Science and Astronomy Graduate School of Arts and SciencesThe University of TokyoKomaba 3-8-1MeguroTokyo 153-8902Japan Geodynamics Research Center Ehime University.Bunkyo-cho 2-5MatsuyamaEhime 790-8577Japan

It has been thought that granitic crust, having been formed on the surface, must have survived through the Earth＇s evolution because of its buoyancy. At subduction zones continental crust is predominantly created by arc magmatism and is returned to the mantle via sediment subduction, subduction erosion, and continental subduction. Granitic rocks, the major constituent of the continental crust, are lighter than the mantle at depths shallower than 270 km, but we show here, based on first principles calcu- lations, that beneath 270 km they have negative buoyancy compared to the surrounding material in the upper mantle and transition zone, and thus can be subducted in the depth range of 270-660 km. This suggests that there can be two reservoirs of granitic material in the Earth, one on the surface and the other at the base of the mantle transition zone （MTZ）. The accumulated volume of subducted granitic material at the base of the MTZ might amount to about six times the present volume of the continental crust. Our calculations also show that the seismic velocities of granitic material in the depth range from 270 to 660 km are faster than those of the surrounding mantle. This could explain the anomalous seismic-wave velocities observed around 660 km depth. The observed seismic scatterers and reported splitting of the 660 km discontinuity could be due to jadeite dissociation, chemical discontinuities between granitic material and the surrounding mantle, or a combination thereof.

关键词： Continental growthGraniteFirst principlesMantle transition zoneTectonicsGeodynamics

Microstructure and mechanical properties of ZrO_2(Y_2O_3)-Al_2O_3 nanocomposites prepared by spark plasma sintering

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Particuology 2012年第3期10卷 345-351页

作者： Shufeng Li Hiroshi Izui Michiharu Okano Weihua Zhang taku Watanabe College of Science and Technology Nihon University7-24-1NarashinodaiFunabashiChiba 274-8501Japan College of Science and Technology Nihon University1-8-14KandasurugadaiChiyoda.Tokyo 101-8308Japan College of Materials Science and Technology Xi'an University of Technology5 SouthJinhua RoadXi'anShaanxi 710048China

Zirconia （yttria）-alumina ceramic nanocomposites were fabricated from different powders by spark plasma sintering （SPS）. One powder was a commercially available nanocomposite powder TZP-3Y2OA, consisting of 3 mol% yttria-stabilized zirconia （3-YSZ） reinforced with 20wt% alumina, and the other, used as a comparison, was a conventional mechanically mixed powder 3YSZ-2OA, a blend made of 3 mol% yttria-stabilized zirconia powder ZrO2 （3Y） and 20 wt% ,x-alumina powder. The effect of the sintering temperature on the densification, the sintering behavior, the mechanical properties and the microstructure of the composites was investigated. The results showed that the density increased with increasing sintering temperature, and thus, the mechanical properties were strengthened because of the increased densification. The nanocomposite powder TZP-3Y20A was easily sintered, and good mechanical properties were achieved as compared with the powder from the conventional mechanically mixed method, the maximum flexural strength and fracture toughness of which were 967 MPa and 5.27 MPa m 1/2, respectively.

关键词： Zirconia-aluminaNanocompositeSpark plasma sintering (SPS)Mechanical propertiesMicrohardnessFracture toughnessDensification

ILES of an array of three subsonic counter-flow jets issuing from a wing leading edge exposed to hypersonic aerodynamic heating

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Advances in Aerodynamics 2020年第1期2卷 236-249页

作者： Tomonori Shimada taku Ohwada Department of Aeronautics and Astronautics Graduate School of EngineeringKyoto UniversityKyoto 615-8530Japan

The flow of an active thermal protection system exploiting subsonic counter-flow jets for wing leading edges of hypersonic vehicles is numerically studied on the basis of the three dimensional Navier-Stokes *** coolant air issuing from around the stagnation point as an array of three jets spreads over both the upper and the lower sides of the cylinder surface and about 40~60%cooling effectiveness is achieved in the range up to 5 degrees angle of attack despite the occurrence of various three-dimensional fluid-dynamic *** numerical scheme is second order accurate but simple inclusion of high order polynomial approximation in the reconstruction enables the capturing of finer structure of the flow field.

关键词： Subsonic jet Counter-flow Aerodynamic heating TPS Rayleigh-Taylor Kelvin-Helmholtz Near-wall streaks

Preoperative portal vein embolization for hepatocellular carcinoma: consensus and controversy

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World Journal of Hepatology 2016年第9期8卷 439-445页

作者： taku Aoki Keiichi Kubota Second Department of Surgery Dokkyo Medical University

Thirty years have passed since the first report of portal vein embolization(PVE),and this procedure is widely adopted as a preoperative treatment procedure for patients with a small future liver remnant(FLR).PVE has been shown to be useful in patients with hepatocellular carcinoma(HCC)and chronic liver ***,special caution is needed when PVE is applied prior to subsequent major hepatic resection in cases with cirrhotic livers,and volumetric analysis of the liver segments in addition to evaluation of the liver functional reserve before PVE is mandatory in such *** in the embolic material and selection of the treatment approach,and combined use of PVE and transcatheter arterial embolization/chemoembolization have yielded improved outcomes after PVE and major hepatic resections.A novel procedure termed the associating liver partition and portal vein ligation for staged hepatectomy has been gaining attention because of the rapid hypertrophy of the FLR observed in patients undergoing this procedure,however,application of this technique in HCC patients requires special caution,as it has been shown to be associated with a high morbidity and mortality even in cases with essentially healthy livers.

关键词： Hepatocellular carcinoma Future liver remnant Poral vein embolization Liver functional reserve The associating liver partition and portal vein ligation for staged hepatectomy