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151.
Saori Imada Kei Hirose Tetsuya Komabayashi Toshihiro Suzuki Yasuo Ohishi 《Physics and Chemistry of Minerals》2012,39(7):525-530
Compression behaviors of two Al-rich phases in the lower mantle, hexagonal new aluminum-rich (NAL) phase and its high-pressure polymorph Ca-ferrite-type (CF) phase, were examined for identical Na0.4Mg0.6Al1.6Si0.4O4 (40?% NaAlSiO4–60?% MgAl2O4) composition. The volumes of the NAL and CF phases were obtained at room temperature up to 31 and 134?GPa, respectively, by a combination of laser-annealed diamond-anvil cell techniques and synchrotron X-ray diffraction measurements. Fitting of the third-order Birch–Murnaghan equation of state to such pressure–volume data yields bulk modulus K 0?=?199(6) GPa at 1?bar and its pressure derivative K 0′?=?5.0(6) for the NAL phase and K 0?=?169(5) GPa and K 0′?=?6.3(3) for the CF phase. These results indicate that the bulk modulus increases from 397 to 407 GPa across the phase transition from the NAL to CF phase at 43 GPa, where the NAL phase completely transforms into the CF phase on Na0.4Mg0.6Al1.6Si0.4O4. Density also increases by 2.1?% across the phase transition. 相似文献
152.
Vinicius Aguiar de Souza Levent Kirkayak Katsuyuki Suzuki Hideyuki Ando Hidetoshi Sueoka 《Ocean Engineering》2012
This paper describes an approach to simulate a seven-tier stack consisting of scaled model of a 20 ft ISO freight container and its linking connectors, denominated twist locks, subjected to dynamical load induced by its base. The physical (dimensions, mass, and moments of inertia) and structural (longitudinal, transversal and torsional stiffness) characteristics of the scaled models were decided based on two dimensionless numbers: ratios between gravity force and inertia force, and elastic force divided by inertia force, through experimental and numerical analysis. A series of experiments with controlled parameters were performed using a shaking table test to understand the effects of each variable in the container stack dynamics and present enough data to validate the numerical model. The results of this study indicate that the numerical model built is a promising tool for further study. Moreover, the model is able to predict conditions close to real situations faced by container stacks while storage on a ship's deck. 相似文献
153.
T. Ichimura M. Hori P. E. Quinay M. L. L. Wijerathne T. Suzuki S. Noguchi 《地震工程与结构动力学》2012,41(4):795-811
The seismic structural response is affected by temporal and spatial variations in strong ground motion. It can be evaluated through the fault‐structure system: the fault mechanism, wave propagation through the crust, amplification near the surface, and soil‐structure interaction. To analyze this system at high resolution and accuracy, we previously proposed a new multiscale analysis method and numerically verified its validity. However, the problem of the extremely large computation cost of constructing a three‐dimensional numerical model and solving the discretized governing equations still remains. Here, we introduce a new method to resolve these difficulties. By combining this new method with our multiscale analysis, we developed a tool for fault‐structure system analysis. The accuracy of this tool is verified by comparing it to a Green's function solution. Finally, we demonstrate the potential utility of the method by estimating the seismic response of a large and complex underground highway junction in a given earthquake scenario. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
154.
Takeshi Yoshimura Koji Suzuki Hiroshi Kiyosawa Tsuneo Ono Hiroshi Hattori Kenshi Kuma Jun Nishioka 《Journal of Oceanography》2013,69(5):601-618
Response of phytoplankton to increasing CO2 in seawater in terms of physiology and ecology is key to predicting changes in marine ecosystems. However, responses of natural plankton communities especially in the open ocean to higher CO2 levels have not been fully examined. We conducted CO2 manipulation experiments in the Bering Sea and the central subarctic Pacific, known as high nutrient and low chlorophyll regions, in summer 2007 to investigate the response of organic matter production in iron-deficient plankton communities to CO2 increases. During the 14-day incubations of surface waters with natural plankton assemblages in microcosms under multiple pCO2 levels, the dynamics of particulate organic carbon (POC) and nitrogen (PN), and dissolved organic carbon (DOC) and phosphorus (DOP) were examined with the plankton community compositions. In the Bering site, net production of POC, PN, and DOP relative to net chlorophyll-a production decreased with increasing pCO2. While net produced POC:PN did not show any CO2-related variations, net produced DOC:DOP increased with increasing pCO2. On the other hand, no apparent trends for these parameters were observed in the Pacific site. The contrasting results observed were probably due to the different plankton community compositions between the two sites, with plankton biomass dominated by large-sized diatoms in the Bering Sea versus ultra-eukaryotes in the Pacific Ocean. We conclude that the quantity and quality of the production of particulate and dissolved organic matter may be altered under future elevated CO2 environments in some iron-deficient ecosystems, while the impacts may be negligible in some systems. 相似文献
155.
Sedimentary facies of the Tsagayan Formation is distributed in the eastern Zeya-Bureya Basin has been analyzed. The formation is of the Maastrichtian to Danian in age and characterized by the cyclicity of the fining-upwards successions. Analysis of environmental changes during the K/T boundary is the focus of this study. Five facies have been identified: Facies A, thick and laterally extensive coarse-grained to medium-grained sandstone units, interpreted as channelfill deposits; Facies B, parallel-laminated to massive mudstone units interpreted as interchannel lakes and flood plain deposits; Facies C, sheet-like medium-grained to fine-grained sandstones interpreted as crevasse splay deposits;Facies D, coal to coaly mudstone beds interpreted as deposits ofpeatlands; Facies E, very poorly sorted sandy mudstone beds interpreted as debris flow deposits. Fluvial environments with the low-relief flat topography was inferred. A channel transported large volumes of clasts, and a flood basin with interchannel lakes and peatlands was deciphered. Any distinct change of sedimentary environments has not been identified throughout the Tsagayan Formation (including the K/T boundary). However, two beds of debris flow deposits were identified. The one occurs at the uppermost part of the lower Tsagayan Subformation and contains dinosaur fossils. The other is intercalated in the upper Tsagayan Subformation. 相似文献
156.
The concentrations of 129I in seawater samples from two sites (off Sekine and the Toyama Bay) in the Japan Sea were determined by accelerator mass spectrometry. The observed concentrations exceed amounts expected from natural origin and globally distributed fallout due to nuclear weapons testing. Because the fraction of natural origin and global fallout is 2% and 8.9–13.8%, respectively, the residual more than 80% of the concentration must come primarily from nuclear fuel reprocessing plants. This result indicates a rapid distribution of 129I through atmospheric transport on a global scale. The depth distribution of 129I at the Toyama Bay in the Japan Sea shows that the 129I maximum is in the mixed layer and that concentrations decrease with depth. The inventory of 129I in water column is four times higher than that measured in the Gulf of Mexico which has almost the same depth at the Toyama Bay. This higher inventory probably reflects: (1) the rapid water sinking in the Japan Sea, (2) the difference of distance in sampling locations with respect to major 129I releasing plants and (3) the strong increase in emissions from nuclear fuel reprocessing plants after the profile of the Gulf of Mexico was taken. 相似文献
157.
Atsushi Suzuki Yusuke Yokoyama Hironobu Kan Kayo Minoshima Hiroyuki Matsuzaki Nozomu Hamanaka Hodaka Kawahata 《Quaternary Geochronology》2008,3(3):226-234
The Meiwa Tsunami, one of the largest tsunamis recorded in historical documents in Japan struck Ishigaki Island and neighboring islands of the Ryukyu Arc in April 1771 AD, killing more than 12 000 people. An enormous number of massive Porites coral boulders are scattered on the shore and in the reef moat of eastern Ishigaki Island. Although these boulders likely were cast ashore by the Meiwa Tsunami, a detailed examination has not yet been conducted. When the marine reservoir effect is taken into account, one of mode values of calibrated radiocarbon dates possibly corresponds to the time of the 1771 event. However, the range of calibrated radiocarbon ages indicates that the transport of the boulders cannot be ascribed solely to the tsunami. Oxygen isotope microprofiling, which indicates sea-surface temperature variation, was therefore conducted to further investigate the mechanism of transport. The results suggest that the skeletal growth of most coral colonies was interrupted in summer or autumn; hence, tropical storms and typhoons are also very likely to be agents of transport. Thus, by combining radiocarbon dating with oxygen isotope microprofiling to investigate Porites coral boulders, it is possible to separate paleotsunami boulders from those transported by storm events as far as tsunamis occurred during the non-storm season. 相似文献
158.
A history of water pollution and countermeasures for water purification in Dokai Bay, Japan are reviewed. Now, Dokai Bay suffers from the occurrences of red tides and oxygen-deficiency in summer. In order to prevent the occurrences of red tides and oxygen-deficiency, an ecological numerical model has been developed. The model experiments forecast that when the phosphorus or nitrogen load from land will be cut by 90% or 95%, respectively, red tides and oxygen-deficiency will not occur in Dokai Bay. If the industrial and sewage facilities are not sufficient to cut the nutrients load to the necessary degree, we have to consider other countermeasures such as cultivating bivalves and algae in order to decrease the nutrients concentration in the bay. International co-operation related to coastal zone management is also discussed. 相似文献
159.
Y. Suzuki 《Planetary and Space Science》1981,29(1):57-63
On the basis of a ray tracing method the propagation and the attenuation of an auroral infrasonic wave are studied. Relations between the direct and reflected waves recorded at the Syowa Station, Antarctica, are clarified with regard to; (1) the delay time, (2) the intensity ratio, and (3) trace velocities. The time required for a wave to travel from the source to the ground is calculated as a function of a source altitude. The retardation time of the wave arrival behind the zenith crossing of the source current is deduced. A method is proposed for estimating the altitude of a source current from the retardation and a trace velocity of the wave. It is concluded that the existence of a supersonic equatorward motion of an electrojet which continues for a certain distance is necessary for the observation of auroral infrasonic waves. This distance must exceed at least 60 km equatorwards from the zenith to enable the direct wave to be observed and with total length of 930 km to enable the reflected wave to be observed. From these conditions it is also concluded that the infrasonic wave is not seen in mid latitudes and the reflected wave is a rare phenomenon. 相似文献
160.
Ohishi Masatoshi Kaifu Norio Suzuki Hiroko Morimoto Masaki 《Astrophysics and Space Science》1986,118(1-2):405-407
A molecular spectral line survey of the title source detected 166 molecular lines from 18 interstellar molecules in the frequency ranges of 34.25–50.00, 83.50–84.50, and 86.00–91.50 GHz. For each molecule, gaussian decomposition of the velocity components in the transition profiles gave consistent radial velocity and linewidth. Rotation diagrams were drawn for each velocity component.Paper presented at the IAU Third Asian-Pacific Regional Meeting, held in Kyoto, Japan, between 30 September–6 October, 1984. 相似文献