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Mantle convection modeling of the supercontinent cycle: Introversion,extroversion, or a combination?

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Geoscience Frontiers 2014年第1期5卷 77-81页

作者： masaki Yoshida M.Santosh Institute for Research on Earth Evolution (IFREE) Japan Agency for MarineeEarth Science and Technology (JAMSTEC) 2-15 Natsushima-choYokosukaKanagawa 237-0061 Japan Division of Interdisciplinary Science Faculty of Science Kochi UniversityAkebono-cho 2-5-1Kochi 780-8520 Japan School of Earth Sciences and Resources China University of Geosciences (Beijing)

The periodic assembly and dispersal of continental fragments, referred to as the supercontinent cycle, bear close relation to the evolution of mantle convection and plate tectonics. Supercontinent formation involves complex processes of ＂introversion＂（closure of interior oceans）, ＂extroversion＂（closure of exterior oceans）, or a combination of these processes in uniting dispersed continental fragments, Recent developments in numerical modeling and advancements in computation techniques enable us to simulate Earth＇s mantle convection with drifting continents under realistic convection vigor and rheology in Earth-like geometry （i.e., 3D spherical-shell）. We report a numerical simulation of 3D mantle convection, incorporating drifting deformable continents, to evaluate supercontinent processes in a realistic mantle convection regime. Our results show that supercontinents are assembled by a combi- nation of introversion and extroversion processes. Small-scale thermal heterogeneity dominates deep mantle convection during the supercontinent cycle, although large-scale upwelling plumes intermit- tently originate under the drifting continents and/or the supercontinent.

关键词： Mantle convection Numerical simulation Tectonics Supercontinent cycle Introversion Extroversion

Degenerate slave-makers,but nevertheless slave-makers?Host worker relatedness in the ant Myrmoxenus kraussei

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Integrative Zoology 2015年第2期10卷 182-185页

作者： masaki SUEFUJI Jürgen HEINZE Zoology/Evolutionary Biology University of RegensburgGermany

Socially parasitic ants of the formicoxenine genus Myrmoxenus exhibit considerable diversity in colony structure and life *** some species are active slave-makers with many workers and others are workerless‘murder-parasites,’Myrmoxenus kraussei is considered as a‘degenerate slave-maker’because of its very low worker ***,we document that Temnothorax recedens host workers in single colonies of *** from Lago di Garda,Italy,exhibit significantly more genetic diversity than workers in unparasitized *** raises the possibility that,despite its low worker numbers,*** may actively engage in slave raids in nature.

关键词： dulosis nestmate relatedness Myrmoxenus social parasitism slave-making

Conjecture with water and rheological control for subducting slab in the mantle transition zone

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Geoscience Frontiers 2015年第1期6卷 79-93页

作者： Fumiko Tajima masaki Yoshida Eiji Ohtani University of California at Irvine 4164 Frederick Reines Hall4IrvineCA 92697USA Institute for Research on Earth Evolution(IFREE) Japan Agency for Marine-Earth Science and Technology(JAMSTEC) Department of Earth and Materials Science Graduate School of ScienceTohoku University

Seismic observations have shown structural variation near the base of the mantle transition zone （MTZ） where subducted cold slabs, as visualized with high seismic speed anomalies （HSSAs）, flatten to form stagnant slabs or sink further into the lower mantle. The different slab behaviors were also accompanied by variation of the ＂660 kin＂ discontinuity depths and low viscosity layers （LVLs） beneath the MTZ that are suggested by geoid inversion studies. We address that deep water transport by subducted slabs and dehydration from hydrous slabs could affect the physical properties of mantle minerals and govern slab dynamics. A systematic series of three-dimensional numerical simulation has been conducted to examine the effects of viscosity reduction or contrast between slab materials on slab behaviors near the base of the MTZ. We found that the viscosity reduction of subducted crustal material leads to a sepa- ration of crustal material from the slab main body and its transient stagnation in the MTZ. The once trapped crustal materials in the MTZ eventually sink into the lower mantle within 20 30 My from the start of the plate subduction. The results suggest crustal material recycle in the whole mantle that is consistent with evidence from mantle geochemistry as opposed to a two-layer mantle convection model. Because of the smaller capacity of water content in lower mantle minerals than in MTZ minerals, dehydration should occur at the phase transformation depth, ~660 kin. The variation of the disconti- nuity depths and highly localized low seismic speed anomaly （LSSA） zones observed from seismic P waveforms in a relatively high frequency band （~ 1 Hz） support the hypothesis of dehydration from hydrous slabs at the phase boundary. The LSSAs which correspond to dehydration induced fluids are likely to be very local, given very small hydrogen （H＋） diffusivity associated with subducted slabs. The image of such local LSSA zones embedded in HSSAs may not be necessarily captured

关键词： Stagnant slab Discontinuity depth variation Deep water transport by subduction Crustal separation Crustal recycling

Prediction of Photosynthetic Carbon Assimilation Rate of Individual Rice Leaves under Changes in Light Environment Using BLSTM-Augmented LSTM

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Computer Modeling in Engineering & Sciences 2022年第12期133卷 557-577页

作者： Masayuki Honda Kenichi Tatsumi masaki Nakagawa Graduate School of Bio-Applications and Systems Engineering Tokyo University of Agriculture and TechnologyKoganei City184-8588Japan Institute of Agriculture Tokyo University of Agriculture and TechnologyFuchu City183-0054Japan Institute of Engineering Tokyo University of Agriculture and TechnologyKoganei City184-8588Japan

A model to predict photosynthetic carbon assimilation rate(A)with high accuracy is important for forecasting crop yield and *** short-term memory(LSTM),a neural network suitable for time-series data,enables prediction with high accuracy but requires mesophyll *** addition,for practical use,it is desirable to have a technique that can predict A from easily available *** this study,we propose a BLSTM augmented LSTM(BALSTM)model,which utilizes bi-directional LSTM(BLSTM)to indirectly reproduce the mesophyll variables required for *** most significant feature of the proposed model is that its hybrid architecture uses only three relatively easy-to-collect external environmental variables—photosynthetic photon flux density(Q_(in)),ambient CO_(2) concentration(C_(a)),and temperature(T_(air))—to generate mesophyll CO_(2) concentration(C_(i))and stomatal conductance to water vapor(g_(sw))as intermediate ***,A is predicted by applying the obtained intermediate outputs to the learning ***,in this study,1)BALSTM(Q_(in),C_(a),T_(air))had a significantly higher A prediction accuracy than LSTM(Q_(in),C_(a),T_(air))in case of using only Q_(in),C_(a),and T_(air);2)BALSTMC_(i),g_(sw),which had C_(i) and g_(sw) as intermediate products,had the highest A prediction accuracy compared with other candidates;and 3)for samples where LSTM(Q_(in),C_(a),T_(air))had poor prediction accuracy,BALSTMC_(i),g_(sw)(Q_(in),C_(a),T_(air))clearly improved the ***,it was found that incorrect predictions may be formed when certain factors are not reflected in the data(e.g.,timing,cultivar,and growth stage)or when the training data distribution that accounts for these factors differs from the predicted data ***,a robust model should be constructed in the future to improve the prediction accuracy of A by conducting gasexchange measurements(including a wide range of external environmental values)and by increasing the

关键词： Hybrid prediction model assimilation rate leaf internal variables recurrent neural network fluctuating light environments rice

Model Analysis of Radar Echo Split Observed in an Artificial Cloud Seeding Experiment

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Journal of Meteorological Research 2016年第3期30卷 386-400页

作者： masaki Shimada KIKURO Tomine KOJI Nishiyama Department of Earth and Ocean Sciences National Defense Academy Faculty of Engineering Kyushu University

An artificial cloud seeding experiment was performed over the Japan Sea in winter to show how massive seeding could be effective to mitigate heavy snowfall *** results showed that 20 min after cloud seeding,a portion of the radar echo beneath the seeding track was weakened to divide the radar echo into two *** order to analyze the results,a numerical simulation was conducted by using the Weather Research and Forecasting model verion *** this simulation,the seeding effects were represented as phenomena capable of changing rain particles by accreting cloud ice and snow to form graupel particles and by changing cloud liquid water to snow *** graupel particles fell rapidly,thus temporarily intensifying the rainfall,which subsequently ***,the weakened radar echo in the field experiment is deemed to have been caused by the increase in rapidly falling graupel particles.

关键词： heavy snowfall artificial cloud seeding numerical experiment

A Rice Phytochrome A in Arabidopsis： The Role of the N-terminus under red and far-red light

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Molecular Plant 2008年第1期1卷 84-102页

作者： Julia Kneissl Tomoko Shinomura masaki Furuya Cordelia Bolle Ludwig-Maximilians-Universitat Munchen Bereich Botanik Menzinger Str. 67 80638 Munchen Germany Hitachi Advanced Research Laboratory Hatoyama Saitama 350-0395 Japan

The phytochrome （phy）A and phyB photoreceptors mediate three photobiological response modes in plants; whereas phyA can mediate the very-low-fluence response （VLFR）, the high-irradiance response （HIR） and, to some extent, the low fluence response （LFR）, phyB and other type U phytochromes only mediate the LFR. To investigate to what level a rice phyA can complement for Arabidopsis phyA or phyB function and to evaluate the role of the serine residues in the first 20 amino acids of the N-terminus of phyA, we examined VLFR, LFR, and HIR responses in phyB and phyAphyB mutant plants transformed with rice PHYA cDNA or a mutant rice PHYA cDNA in which the first 10 serine residues were mutated to alanines （phyA SA）. Utilizing mutants without endogenous phyB allowed the evaluation of red-light-derived responses sensed by the rice phyA. In summary, the WT rice phyA could complement VLFR and LFR responses such as inhibition of hypocotyl elongation under pulses of FR or continuous R light, induction of flowering and leaf expansion, whereas the phyA SA was more specific for HIR responses （e.g. inhibition of hypocotyl elongation and anthocyanin accumulation under continuous far-red light）. As the N-terminal serines can no longer be phosphorylated in the phyA SA mutant, this suggests a role for phosphorylation discriminating between the different phyA-dependent responses. The efficacy of the rice phyA expressed in Arabidopsis was dependent upon the developmental age of the plants analyzed and on the physiological response, suggesting a stage-dependent downstream modulation of phytochrome signaling.

关键词： phytochrome (phy) high-irradiance response (HIR) very-low-fluence response (VLFR)

Carbonation of low heat portland cement paste precured in water for different time

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Journal of University of Science and Technology Beijing 2007年第2期14卷 178-184页

作者： Deping Chen Etsuo Sakai masaki Daimon Yoko Ohba Civil and Environmental Engineering School University of Science and Technology Beijing Beijing 100083 China Graduate School of Science and Engineering Tokyo Institute of Technology Tokyo 152-8552 Japan

The carbonation technique was applied to accelerate the hydration of low heat portland cement （LHC）. Before carbonation, the demoulded pastes were precured in water for 0, 2, 7, and 21 d, respectively. The results show that precuring time in water strongly influences the carbonation process. The phenolphthalein test indicates that the paste precured in water for a shorter time is more quickly carbonated than that for a longer time. The content of calcium hydroxide increases with increasing the precuring time in water, whereas, the amount of absorbed carbon dioxide changes contrarily. Scanning electron microscope （SEM） observation shows that portlandite always fills up big air bubbles in the paste during precuring in water, and the mercury intrusion porosimetry （MIP） results show that there are less large capillary pores in the paste precured in water for a longer time. It is found that the paste without precuring in water has more carbon dioxide absorption during curing in carbon dioxide atmosphere, and its total pore volume decreases remarkably with an increase in the carbonation time than that precured in water. X-ray diffraction （XRD） and Brunauer-Emmett-Teller （BET） surface area analyses indicate that the carbonate products are vaterite and calcite; CxSHy formed from carbonation has low BET surface area in comparison with that of C-S-H formed from curing in water.

关键词： carbonation carbon dioxide absorption vaterite BET surface area pore size distribution

Energetics of the Solid Earth:An integrated perspective

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能源地球科学(英文) 2020年第1期1卷 28-35页

作者： masaki Yoshida M.Santosh Geophysical Research Group Research Center for Volcanoes and Earth’s InteriorJapan Agency for Marine-Earth Science and Technology(JAMSTEC)2-15 Natsushima-choYokosuka237-0061Japan School of Earth Sciences and Resources China University of GeosciencesBeijing100083China Department of Earth Sciences School of Physical SciencesUniversity of AdelaideSA5005Australia

The internal energy of the Solid Earth is mainly transferred through thermal convection of the ***,we discuss the 10^(20)-J-scale energy relating to the dynamics of the Solid Earth’s *** energy released from the interior of the present-day Earth to outer space per year is estimated as E_(earth)=1.4×10^(21) J yr^(-1) based on the recent dataset of globally observed crustal heat flow,which is a factor of two or three times larger than the annual energy consumption of the total population of the world,5.7×10^(20) J yr^(-1).Of the energy from global crustal heat flow,the energy released by all of the major hotspot plumes in volcanic vents per year is estimated as E_(plume)=7.2×10^(19) J yr^(-1),which is approximately only 6%of the *** propose that a large number of mantle plumes have not emerged as hotspots on the Earth’s surface,with the possibility that Eplume is larger than expected if the energy released from small seamounts of the Earth is *** the heat(energy)budget of the Earth,the heat production by the decay of radioactive isotopes in the mantle and crust is nearly comparable to the heat released by the secular cooling of the *** Eearth,the annual energy released by the secular cooling of the Earth is estimated as 6.6×10_(20) J yr^(-1).This energy is closely related to the geothermal energy from our planet.

关键词： Solid earth Energy Hot spots Earthquakes Volcanic eruptions

Generation of micro/nano hybrid surface structures on copper by femtosecond pulsed laser irradiation

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Nanomanufacturing and Metrology 2022年第3期5卷 274-282页

作者： Ayumi Nakajima masaki Omiya Jiwang Yan School of Integrated Design Engineering Graduate School of Science and TechnologyKeio UniversityYokohama 223-8522Japan Department of Mechanical Engineering School of Science and TechnologyKeio UniversityYokohama 223-8522Japan

The delamination of copper lead frames from epoxy molding compounds(EMC)is a severe problem for microelectronic devices,as it leads to reduced heat dissipation or circuit *** micro/nanoscale surface structuring of copper is a promising method to improve the copper-EMC interfacial *** this study,the generation of micro/nano hybrid structures on copper surfaces through femtosecond pulsed laser irradiation is proposed to improve interfacial *** micro/nano hybrid structures were realized by generating nanoscale laser-induced periodic surface structures(LIPSS)on microscale parallel *** types of hybrid surface structures were generated by changing the laser polarization direction,fluence,and scanning *** a specific aspect ratio of microgrooves,a latticed structure was generated on the sides of microgrooves by combining LIPSS formation and direct laser interference *** study provides an efficient method for the micro/nanoscale hybrid surface structure formation for interfacial adhesion improvement between copperand EMC.

关键词： Femtosecond pulsed laser Copper Metal surface LIPSS Direct laser interference patterning-Micro/nano hybrid structures