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排序方式: 共有434条查询结果,搜索用时 234 毫秒
171.
In order to effectively utilize results from quasi-static cyclic testing on structural components for the earthquake-induced collapse risk quantification of structures, the need exists to establish collapse-consistent loading protocols representing the asymmetric lateral drift demands of structures under low-probability of occurrence earthquakes. This paper summarizes the development of such protocols for experimental testing of steel columns prone to inelastic local buckling. The protocols are fully defined with a deformation- and a force-controlled parameter. They are generally applicable to quantify the capacity and demands of steel columns experiencing constant and variable axial load coupled with lateral drift demands. Through rigorous nonlinear earthquake collapse simulations, it is found that the building height, the column's local slenderness ratio, and ground motion type have the largest influence on the dual-parameter loading protocol indexes. Comprehensive comparisons with measured data from full-scale shake table collapse tests suggest that unlike routinely used symmetric cyclic loading histories, the proposed loading protocol provides sufficient information for modeling strength and stiffness deterioration in steel columns at large inelastic deformations. 相似文献
172.
A dataset of continental river discharge based on JRA-55 for use in a global ocean circulation model
Tatsuo Suzuki Dai Yamazaki Hiroyuki Tsujino Yoshiki Komuro Hideyuki Nakano Shogo Urakawa 《Journal of Oceanography》2018,74(4):421-429
A dataset of historical river discharge into oceans was created using the CaMa-Flood global river routing model and adjusted runoff from the land component of JRA-55. The major rivers were well resolved with a 0.25° horizontal resolution. The total runoff on each drainage basin exhibits a distinctive bias on decadal time scales. The input runoff data were modified using 5-year low-pass-filtered multiplicative factors to fit the annual mean climatology and decadal variations in the reference dataset. The model incorporated data from 1958 to 2016. The yearly and seasonal variations of the major rivers are well represented by the model. 相似文献
173.
Aoki Koji Sakamaki Tatsuya Ohashi Tomonori Ikeda Osamu Suzuki Akio 《Physics and Chemistry of Minerals》2020,47(6):1-9
Physics and Chemistry of Minerals - A black tourmaline sample from Seagull batholith (Yukon Territory, Canada) was established to be a schorl with concentrations of Fe2+ among the highest currently... 相似文献
174.
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
175.
Keita W. Suzuki Akihide Kasai Takane Isoda Kouji Nakayama Masaru Tanaka 《Estuarine, Coastal and Shelf Science》2008
To assess the potential of stable isotope ratios as an indicator of fish migration within estuaries, stable isotope ratios in important zooplankton species were analyzed in relation to estuarine salinity gradients. Gut contents from migratory juveniles of the euryhaline marine fish Lateolabrax japonicus were examined along the Chikugo River estuary of the Ariake Sea, which has the most developed estuarine turbidity maximum (ETM) in Japan. Early juveniles in March and April preyed primarily on two copepod species; Sinocalanus sinensis at lower salinities and Acartia omorii at higher salinities. Late juveniles (standard length > 40 mm) at lower salinities preyed exclusively on the mysid Acanthomysis longirostris until July and complementarily on the decapod Acetes japonicus in August. These prey species were collected along the estuary during the spring–summer seasons of 2003 and 2004, and their carbon and nitrogen stable isotope ratios (δ13C and δ15N) were evaluated. The δ13C values of prey species were distinct from each other and were primarily depleted within and in close proximity to the ETM (salinity < 10); S. sinensis (−26.6‰) < Acanthomysis longirostris (−23.3‰) < Acartia omorii (−21.1‰) < Acetes japonicus (−18.5‰). The overall gradient of δ13C with salinity occurred for all prey species and showed minor temporal fluctuations, while it was not directly influenced by the δ13C values in particulate organic matter along the estuary. In contrast to δ13C, the δ15N values of prey species did not exhibit any clear relationship with salinity. The present study demonstrated that δ13C has the potential for application as a tracer of fish migration into lower salinity areas including the ETM. 相似文献
176.
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
177.
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
178.
The frequency of Be and Ae stars in spectroscopic binaries and Algol binaries is examined based on the available catalogue data, and compared with that of stars in theBright Star Catalogue. It is shown that in binary systems Be and Ae stars reveal different statistical behaviours. The frequency of Be stars in spectroscopic binaries shows a notable peak in its orbital-period distribution in the range of 100–300 days, suggesting a statistical group separated from Algol systems. In contrast, most of Ae stars in spectroscopic binaries belong to the Algol systems. 相似文献
179.
The -ray and white-light flare of 13 May, 1981 is used for a study of spatial distributions of energetic electrons and high-temperature plasma. 相似文献
180.
The role of the grain boundary at chemical and isotopic fronts in marble during contact metamorphism
Hideki Wada Takamaru Ando Masayuki Suzuki 《Contributions to Mineralogy and Petrology》1998,132(4):309-320
Carbon and oxygen isotopic profiles around a low pressure metasomatic wollastonite reaction front in a marble of the Hida
metamorphic terrain, central Japan, display typical metamorphic fluid-enhanced isotopic zonations. Isotopic profiles obtained
from detailed microscale analyses perpendicular to the chemical reaction front in calcite marble show that diffusion-enhanced
isotopic exchange may control these profiles. Carbon and oxygen isotopic behaviour in grain boundaries is remarkably different.
Oxygen isotopic troughs (18O depleted rims) around the calcite-grain boundaries are widely observed in this contact aureole, demonstrating that diffusion
of oxygen in calcite grain boundary dominates over lattice diffusion in calcite. In contrast, no difference is observed in
carbon isotopic profiles obtained from grain cores and rims. There is thus no specific role of the grain boundary for diffusion
of carbonic species in the metamorphic fluid during transportation. Carbon chemical species such as CO2 and CO3 ions in metamorphic fluid migrate mainly through lattice diffusion. The carbon and oxygen isotope profiles may be modelled
by diffusion into a semi-infinite medium. Empirically lattice diffusion of oxygen isotopes is almost six times faster than
that of carbon isotopes, and oxygen grain-boundary diffusion is ten times faster than oxygen lattice diffusion. Oxygen isotopic
results around the wollastonite vein indicate that migration of the metamorphic fluid into calcite marble was small and was
parallel to the aquifer. From the stability of wollastonite and the attainment of oxygen isotopic equilibrium, we suggest
that diffusion of oxygen occurred through an aqueous fluid phase. The timescale of formation of the oxygen isotopic profile
around the wollastonite vein is calculated to be about 0.76 × 106 years using the experimentally determined diffusion constant.
Received: 14 January 1997 / Accepted: 23 April 1998 相似文献