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排序方式: 共有216条查询结果,搜索用时 15 毫秒
71.
Yutaka Nakamura Akira Fukukita Kazuo Tamura Issei Yamazaki Taichi Matsuoka Kazuhiko Hiramoto Katsuaki Sunakoda 《地震工程与结构动力学》2014,43(4):507-527
This paper presents a new type of electromagnetic damper with rotating inertial mass that has been developed to control the vibrations of structures subjected to earthquakes. The electromagnetic inertial mass damper (EIMD) consists of a ball screw that converts axial oscillation of the rod end into rotational motion of the internal flywheel and an electric generator that is turned by the rotation of the inner rod. The EIMD is able to generate a large inertial force created by the rotating flywheel and a variable damping force developed by the electric generator. Device performance tests of reduced‐scale and full‐scale EIMDs were undertaken to verify the basic characteristics of the damper and the validity of the derived theoretical formulae. Shaking table tests of a three‐story structure with EIMDs and earthquake response analyses of a building with EIMDs were conducted to demonstrate the seismic response control performance of the EIMD. The EIMD is able to reduce story drifts as well as accelerations and surpasses conventional types of dampers in reducing acceleration responses. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
72.
Hiroshi Nagasawa Kazuo Yamakoshi Tadashi Shimamura 《Geochimica et cosmochimica acta》1979,43(2):267-272
The possible existence of meteoritic spherules was investigated among several silicate spherules separated from oceanic sediments and analyzed by means of INAA (instrumental neutron activation analysis).A 0.72 mg glassy spherule was found to have uniform enrichment of 4 ~ 5 for the refractory REE (rare earth elements) and Sc with substantial depletion of Ce relative to chondritic abundances. This implies that this spherule is meteoritic in origin and that the enrichment of refractory elements was established by high temperature heating in a high O/H environment, possibly at the time of entering the Earth's atmosphere.The other three analyzed spherules showed major and trace element abundances that are consistent with an origin in the oceanic environment. 相似文献
73.
Moored instrument observations in the Kuroshio south of Kyushu 总被引:1,自引:0,他引:1
Masaki Takematsu Kazuo Kawatate Wataru Koterayama Toshiro Suhara Hisashi Mitsuyasu 《Journal of Oceanography》1986,42(3):201-211
In each of the (fiscal) years 1979–1982, multilayer current measurements by means of moored instruments were carried out in the Kuroshio off Tanegashima Island, south of Kyushu, with particular interest in the baroclinic layer (0–1,000 m) of the intense current. Most of the moored instruments were in position for more than 30 days, the maximum duration being 145 days. This paper describes some noticeable features of the mean and fluctuation fields in the surface Kuroshio as inferred from the the new data sets.Vertical profiles of horizontal velocities show that the eastward current of the Kuroshio in the region is confined to the upper 600 m on average and below this level the mean current is directed to the southwest along the local isobaths. This is believed to be the first observation of the level of no motion in this region. It is argued that the indicated level of no motion would lead to much smaller values for the Kuroshio transport than previous values referred to the 1,000 m level — for example, earlier estimates by Nitani (1972).The fluctuation field in the upper intense current appears to be dominated by an organized motion with a time scale of about 30 days. This can be seen clearly in the time variations of water temperature and local volume transport, but less clearly in the velocity records. The horizontal transfer components of momentum and heat are calculated and it is suggested that the transverse momentum transfer, UV tends to be negative (offshore) in the region of anticyclonic shear of the upper Kuroshio; no evidence for a negative eddy viscosity effect is found. 相似文献
74.
Osamu Katoh Kazuyuki Teshima Katsuhiko Kubota Kazuo Tsukiyama 《Journal of Oceanography》1996,52(1):93-108
In order to clarify detailed current structures west of Kyushu, ADCP measurements were carried out in July and September 1990 by the quadrireciprocal method (Katoh, 1988) for removing diurnal and semidiurnal tidal flows from observed flows. On the basis of these results, together with data of routine oceanographic observations, we study the downstream transition of the Tsushima Current west of Kyushu in summer. In the southwest of the Goto Islands, a northward current identified as the Tsushima Current was clearly found. In the south of Cheju, a westward current bifurcated from the Tsushima Current. In the northwest of the Goto Islands, the Tsushima Current narrowed and its velocity became strengthened. Salinity of the Tsushima Current water was much diluted by a current from the Cheju Strait. Near the west coast of the Goto Islands, a countercurrent bifurcating from the Tsushima Current often occurred. The volume transport of the Tsushima Current was 2.3 Sv (1 Sv=106 m3s–1) on the northern side of latitude 31°N. The substantial bifurcation of the Tsushima Current toward the Eastern and Western Channels of the Tsushima Strait occurred in the vicinity of Tsushima. The volume transport through the Western Channel was two to three times larger than that through the Eastern Channel. The baroclinic component in volume transport of the Tsushima Current west of Kyushu was much smaller than that in the Japan Sea. 相似文献
75.
Kazuo Kawatate 《Progress in Oceanography》1986,17(3-4)
On the basis of a lumped mass method in two-dimension, we derive a dynamic calculation method for a system including both extensible and inextensible underwater lines. The Newmark beta method is used in numerical integration with respect to time. The Newton Raphson method is applied so that the numbers of iterations are reduced. A transient response of a line during deployment is calculated. 相似文献
76.
77.
Masahiro Narukawa Masahiro Sakata Kohji Marumoto Kazuo Asakura 《Journal of Oceanography》2006,62(3):249-257
In Tokyo Bay the concentrations of dissolved gaseous mercury (DGM) in the surface seawater and total gaseous mercury (TGM)
over the sea were measured during December 2003, October 2004 and January 2005. Based on these data, the evasional fluxes
of mercury from the sea surface were estimated using a gas exchange model. In addition, an automatic wet and dry deposition
sampler was used to measure the wet and dry depositional fluxes of mercury from December 2003 to November 2004 at three locations
in and near Tokyo Bay. The results indicate that the average DGM and TGM levels of seven locations are 52 ± 26 ng m−3 and 1.9 ± 0.6 ng m−3, respectively, which shows that the surface seawater in Tokyo Bay is supersaturated with gaseous mercury, leading to an average
mercury evasional flux of 140 ± 120 ng m−2d−1. On the other hand, the annual average wet and dry depositional fluxes of mercury at three locations were 19 ± 3 μg m−2yr−1 and 20 ± 9 μg m−2yr−1, respectively. These depositional fluxes correspond to the daily average total depositional flux of 110 ± 20 ng m−2d−1. Thus, it is suggested that in Tokyo Bay, the evasional fluxes of mercury are comparable to the depositional fluxes. 相似文献
78.
Regionalcharacteristicsofstressfieldinthesouthernpartofthenorth-southseismicbeltinChinaanditsrelationwithplate movementJi-Ren... 相似文献
79.
Kazuo Abe 《Journal of Oceanography》2007,63(2):341-347
From April 2005 to March 2006, the concentration of dissolved cadmium (Cd) was monitored in the surface seawater of Urasoko
Bay, which is in a subtropical area of the North Pacific Ocean and is surrounded by a well-developed fringing reef. During
this period, the observed salinity and Cd concentrations varied in a range of approximately 16–34.5 and 4.8–77.8 pM, respectively.
The concentration range of Cd obtained in this study was considered to be too low to damage the coral species, and its variation
throughout the year did not show any seasonality and was not connected with climate data. The Cd-salinity plot for all the
data in the salinity range over 26 showed apparent non-conservative behavior, which suggests a possible irregular input of
Cd from a solid phase through streams and groundwater, release from bottom sediments, and atmospheric deposition into the
bay. 相似文献
80.
Pi-SAR极化数据与K分布指数估算森林生物量与实验验证 总被引:1,自引:0,他引:1
用2002年和2003年日本Pi-SAR全极化数据,研究日本北海道苫小牧森林地区的森林生物量.雷达后向散射系数随森林生物量的增大而增大并迅速达到饱和,L波段雷达数据饱和点约为40t/hm2,X波段仅约为20t/hm2.在SAR数据统计分布中,K分布的指数参数在饱和点以上仍随生物量的增大而增大,并且HV极化方式时相关性最高.根据交叉极化数据K分布的指数参数与森林生物量的关系,本文估算了23个观测点的森林生物量,结果表明平均准确率为85%.因此该算法可以作为一种新的估算森林生物量的手段. 相似文献