In situ X-ray diffraction measurements of the <Emphasis Type="Italic">fcc</Emphasis>–<Emphasis Type="Italic">hcp</Emphasis> phase transition boundary of an Fe–Ni alloy in an internally heated diamond anvil cell     

Tetsuya?KomabayashiEmail author  Kei?Hirose  Yasuo?Ohishi 《Physics and Chemistry of Minerals》2012,39(4):329-338

The phase transition boundary between the face-centered cubic (fcc) structure and hexagonal close-packed (hcp) structure in an Fe–Ni alloy was determined at pressures from 25 to 107 GPa by using an internally resistive-heated diamond anvil cell (DAC), combined with in situ synchrotron X-ray diffraction measurements. The fcc–hcp phase transition boundary in Fe–9.7 wt% Ni is located at slightly lower temperatures than that in pure Fe, confirming the previous understanding that the addition of Ni expands the stability field of the fcc phase. The dP/dT slope of the boundary was determined to be 0.0426 GPa/K, which is slightly larger than that of pure Fe. The pressure interval of the two-phase region is about 6 GPa at a constant temperature, implying that the previous estimates by laser-heated DAC experiments of 10–20 GPa were overestimated. The two-phase region of fcc + hcp would be limited to a pressure of about 120 GPa even in Fe–15 wt%Ni, excluding the possibility of the existence of the fcc phase in the inner core if the simple linear extrapolation of the two-phase region is applied. The pressure and temperature dependences of the c/a axial ratio of the hcp phase in Fe–9.7 wt% Ni are generally consistent with those in pure Fe, suggesting that Ni has minor effects on the c/a ratio.  相似文献   

Nonlinear sloshing in a floating‐roofed oil storage tank under long‐period seismic ground motion     

Tetsuya Matsui  Takashi Nagaya 《地震工程与结构动力学》2013,42(7):973-991

A hybrid analytical and FEM is proposed to investigate the nonlinear sloshing in a floating‐roofed oil storage tank under long‐period seismic ground motion. The tank is composed of a rigid cylindrical wall and a flat bottom, whereas the floating roof is treated as an elastic plate undergoing large deflection. The contained liquid is assumed to be inviscid and incompressible, and the flow is assumed to be irrotational. The method of analysis is based on representation of the liquid motion by superposing the analytical modes that satisfy the Laplace equation and the rigid wall and bottom boundary conditions. The FEM is then applied to solve the remaining kinematic and dynamic boundary conditions at the moving liquid surface coupled with the nonlinear equation of motion of the floating roof. This requires only the discretization of the liquid surface and the floating roof into finite elements, thus leading to a computationally efficient and accurate method compared with full numerical analysis. As numerical examples to illustrate the applicability of the proposed method, two oil storage tanks with single‐deck type floating roofs damaged during the 2003 Tokachioki earthquake are studied. It is shown that the nonlinear oscillation modes with the circumferential wave numbers 0, 2 and 3 caused by the finite liquid surface elevation as well as the membrane action due to large deflection of the deck produce excessively large stresses in the pontoon, which may cause the catastrophic failure of pontoon followed by the submergence of the roof. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Variable stars in the Magellanic Clouds – II. The data and infrared properties     

Yoshifusa Ita †  Toshihiko Tanabé  Noriyuki Matsunaga  Yasushi Nakajima  Chie Nagashima  Takahiro Nagayama  Daisuke Kato  Mikio Kurita  Tetsuya Nagata  Shuji Sato  Motohide Tamura  Hidehiko Nakaya  Yoshikazu Nakada 《Monthly notices of the Royal Astronomical Society》2004,353(3):705-712

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Diurnal variation of CO₂ concentration, Δ¹⁴C and δ¹³C in an urban forest: estimate of the anthropogenic and biogenic CO₂ contributions     

Hiroshi A. Takahashi  Eiichi Konohira  Tetsuya Hiyama  Masayo Minami  Toshio Nakamura  Naohiro Yoshida 《Tellus. Series B, Chemical and physical meteorology》2002,54(2):97-109

Diurnal variation in the atmospheric CO₂ concentration and the carbon isotopic composition (Δ¹⁴C and δ¹³C) was measured in a forest in an urban area on 9 February 1999. The carbon isotope approach used in the present study differentiated between the quantitative contributions from anthropogenic and biogenic CO₂ sources in the urban atmosphere. The anthropogenic (fossil fuel) and biogenic (soil respiration) contributions was estimated, and they ranged from 1 to 16% and from 2 to 8% of the total atmospheric CO₂. The diurnal variation of the anthropogenic CO₂ was the major cause of the total atmospheric CO₂ variation, while the biogenic CO₂ remained relatively constant throughout the day. Estimating the contribution of soil respired CO₂ provided the mean residence time of soil respired CO₂ within the forest atmosphere.  相似文献   

Frost heave analysis of ballasted track above box culvert and its influence on train vibration     

Bin Luo  Hao Lai  Tatsuya Ishikaw  Tetsuya Tokoro 《寒旱区科学》2017,9(3):229-235

The uneven frost heave of frost-susceptible subgrade soil causes track irregularity, which highly enhances train vibration and affects the comfort and safety of railway transportation. This paper presents a coupled thermo-hydro-mechanical (THM) analysis for the freezing behavior of railway located above a box culvert. The vertical acceleration of the vehicle, an indicator of riding comfort, is predicted through a vehicle dynamic model. The results reveal that the existence of a box culvert changes the subgrade thermal pattern, leading to a deeper frost penetration depth. The frost heave amount above the box culvert is larger than the adjacent section, resulting in uneven track structure upheave and track irregularity. This frost-induced track irregularity highly affects train vibration.  相似文献   

Evidence for the significant role of sea surface temperature distributions over remote tropical oceans in tropical cyclone intensity     

Anitha Kumari Hegde  Ryuichi Kawamura  Tetsuya Kawano 《Climate Dynamics》2016,47(1-2):623-635

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Preface to the Special Issue on Summer 2020: Record Rainfall in Asia — Mechanisms,Predictability and Impacts     

Robin T.CLARK  Xiquan DONG  Chang-Hoi HO  Jianhua SUN  Huiling YUAN  Tetsuya TAKEMI 《大气科学进展》2021,38(12):1977-1979

Throughout vast areas of Asia, the summer of 2020 was extraordinarily wet. After an exceptionally wet May in North-east India and Bangladesh, excessive rainfall hit at least 10 provinces in central and southern China in June and July, caus-ing extensive flooding in many rural and urban locations. Long standing rainfall, lake and river level records were con-sequently broken in several parts of the region with the Yangtze-Huaihe river valleys, particularly badly impacted, with con-sequential economic losses. Floods and landslides also affected parts of Japan with at least one location in Kumamoto province even experiencing a record-breaking 1000 mm of rainfall in just 3 days in early July. The 2020 wet season in South Korea was also exceptionally long, lasting 54 days, compared to their more usual 32.  相似文献   

Surface energy partitioning and evapotranspiration over a double‐cropping paddy field in Bangladesh     

Md. Shahadat Hossen  Masayoshi Mano  Akira Miyata  Md. Abdul Baten  Tetsuya Hiyama 《水文研究》2012,26(9):1311-1320

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An eddy-resolving simulation of the diurnal variation of fair-weather convection and tracer transport     

Tetsuya Takemi   《Atmospheric Research》2008,89(3):270-282

Tracer transport in the atmosphere is controlled not only by synoptic-scale to mesoscale weather disturbances but also by microscale boundary-layer processes especially under fair-weather conditions. The present study investigates numerically the diurnal variation of boundary-layer convection and cumulus clouds and their role in transporting tracers by conducting high-resolution simulations that explicitly resolve turbulent eddies. The transport of dust aerosols in a desert area under two distinct stability conditions is specifically examined. Convection plays a significant role in transporting dust upward; in other words, the vertical depth of the dust transport is critically determined by the depth of convection. Deep convection is effective in transporting dust into the free atmosphere. The early morning stratification strongly regulates the temporal evolution and the vertical growth of convection and therefore the amount of tracer emission and transport. A sensitivity to model resolution of O (1 km) in a cloud-resolving simulation range is also examined. A proper parameterization for activating microscale convection is required for representing the diurnal variation of convection and tracer transport.  相似文献   

Impact of seas/lakes on polar meteorology of Titan: Simulation by a coupled GCM-Sea model   总被引：1，自引：0，他引：1  

Tetsuya Tokano 《Icarus》2009,204(2):619-636

The detection of large hydrocarbon seas/lakes near the poles by the Cassini spacecraft raises the question as to whether and how polar seas affect the meteorology on Titan. The polar meteorology and methane hydrological cycle in the presence of seas are investigated by a three-dimensional atmospheric general circulation model coupled to a one-dimensional sea energy balance model considering the observed sea/lake geography. The sea composition has a large control on the seasonal evolution of seas, temperature and wind system in the polar region, particularly in the north where large seas are located. The surface of ethane-rich seas, which do not evaporate methane, undergo a large seasonal temperature variation and the sea surface is often warmer than the surrounding land surface. Land breeze in summer towards the seas causes a moisture convergence over the seas, which leads to enhanced summer precipitation in the sea area. On the other hand, methane-rich seas evaporate some methane and are therefore colder than the surroundings. This causes a sea breeze across the north pole in summer, which blows away the moisture from the polar region, so precipitation becomes scarce in the north polar region. The breeze can become stronger than the tidal wind. Sea evaporation peaks in winter, when the temperature and average methane mixing ratio in the planetary boundary layer become lowest. The sea level predominantly rises in summer by precipitation and retreats in winter by evaporation. The meteorology in the south polar region is less sensitive to the composition of the lakes because of the paucity and smallness of southern lakes. Lake-effect precipitation can occur either by moisture convergence by the breeze or humidity enhancement over the seas, but is more characteristic of warm seasons than of cold seasons.  相似文献