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1.
The cosmological perturbation theory is revisited from the holographic point of view. In the case of the single brane model,
it turns out that the AdS/CFT correspondence plays an important role. In the case of the two-brane model, it is shown that
the effective equations of motion becomes the quasi-scalar-tensor gravity. It is also demonstrated that the radion anisotropy
gives the CMB fluctuations through the Sachs-Wolfe effect.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
2.
In this study we test Talley's hypothesis that Oyashio winter mixed-layer water (26.5–26.6σ θ) increases its density to produce the North Pacific Intermediate Water (NPIW) salinity minimum (26.7– 26.8σθ) in the Mixed Water Region, assuming a combination of cabbeling and double diffusion. The possible density change of Oyashio
winter mixed-layer water is discussed using an instantaneous ratio of the change of temperature and salinity along any particular
intrusion (R
l
). We estimate the range of R
l
DD
required to convert Oyashio winter mixed-layer water to the NPIW salinity minimum due to double diffusion, and then assume
double-diffusive intrusions as this conversion mechanism. A double-diffusive intrusion model is used to estimate R
l
DD
in a situation where salt fingering dominates vertical mixing, as well as to determine whether Oyashio winter mixed-layer
water can become the NPIW salinity minimum. Possible density changes are estimated from the model R
l
DD
by assuming the amount of density change due to cabbeling. From these results, we conclude that Oyashio winter mixed-layer
water contributes to a freshening of the lighter layer of the NPIW salinity minimum (around 26.70σθ) in the MWR. 相似文献
3.
Jiro Yoshida Hideo Sudo Masaji Matsuyama Yoshihiro Kurita Yuji Mine 《Journal of Oceanography》1993,49(1):121-129
A comparison between Japan-equator XBT sections along 150°E in late November 1989 and along 140°E in early December 1991 is made. The warmest surface water above 29°C diminished to the south of 2–4°N and the surface mixed layer noticeably decreased in thickness in the equatorial region in December 1991; besides, the North Equatorial Countercurrent was intensified. This is considered to be a manifestation of changes in the surface layer of the western equatorial Pacific in the mature phase of El Niño. 相似文献
4.
A new algorithm has been developed to determine the position of a Data Collection Platform (DCP) that is used for the ARGOS Localization and Data Collection System. The algorithm uses an estimation scheme to correct the orbital parameters to achieve accurate positioning of the NOAA meteorological satellite. It is proved that the positioning accuracy of a DCP by the method of orbital Paramater correction is superior to the translocation method.Positioning of a moving DCP was also attempted by installing a DCP on board a vessel. 相似文献
5.
Direct current measurements by a shipboard and bottom-mounted acoustic Doppler current profiler and concurrent hydrographic observations with a CTD were conducted off southeastern Hokkaido, Japan, between January and May 2005 to reveal temporal variations in the current structure and volume transport of the Coastal Oyashio (CO). The CO, which has a baroclinic jet structure with southwestward speeds exceeding 90 cm s?1 and a width of 7–8 km, was associated with a surface-to-bottom density front and was formed on the offshore side of the shelf break. The volume transport of CO (T CO) was estimated by integrating the fluxes of lower-density water that was trapped against the coast along the density front represented by the 26.2 σ θ isopycnal line. This transport decreased monotonously from 0.79 Sv (1 Sv = 106 m3 s?1) in January to 0.21 Sv in March and subsequently to 0.12 Sv in May, possibly due to the decay of the East Sakhalin Current Water in the Okhotsk Sea. Accompanied by a decrease in T CO, the location of the jet structure associated with the density front moved toward the coast while the maximum speed of the jet decreased and the tilt of the front became more horizontal. Consequently, more saline offshore Oyashio water flowed into the deep part of the shelf area, and the current structure altered from relatively barotropic in winter to baroclinic in spring. This study is the first to estimate the observed volume transport of the CO from direct current measurements. 相似文献
6.
Yoshihiko Kariya Go Sato Kuniyasu Mokudai Jiro Komori Masaki Ishii Ryoko Nishii Yosuke Miyazawa Noriko Tsumura 《Landslides》2007,4(1):91-94
This paper describes a rockfall event in the Daisekkei Valley of Mount Shirouma-dake (2,932 m), the northern Japanese Alps.
The rockfall occurred on a steep cliff comprising well-jointed felsites and produced debris of ≥8,000 m3. Most debris was deposited on an elongated snowpatch located immediately beneath the cliff, and it caused casualties among
people who were trekking along a trail on the snowpatch. Additionally, a large rock block slipped 1 km on the snowpatch. The
rockfall could have been due to the differential retreat of the rockwall, which contains areas of high- and low-density joints.
Seasonal and diurnal freeze–thaw activities and snow avalanches and wash appear to be important factors responsible for the
retreat. Although some rock blocks that can collapse further remain on the rockwall, the position of the mountain trail in
the Daisekkei Valley is fixed. Fundamental reform of tourism systems for climbers, including education on natural hazards,
is required. 相似文献
7.
GIS-based spatial and temporal prediction system development for regional land subsidence hazard mitigation 总被引：3，自引：0，他引：3
An integrated GIS-based approach for establishing a spatial and temporal prediction system for groundwater flow and land subsidence is proposed and applied to a subsidence-progressed Japanese coastal plain. Various kinds of fundamental data relating to groundwater flow and land subsidence are digitized and entered into a GIS database. A surface water hydrological cycle simulation is performed using a GIS spatial data operation for the entire plain, and the spatial and temporal groundwater infiltration quantity is hereby obtained. Through the data transformation from the GIS database to a groundwater flow code (MODFLOW), a 3D groundwater flow model is established and unsteady groundwater flow simulation for the past 21 years is conducted with results which compare satisfactorily with observed results. Finally, a Visual Basic code is developed for land subsidence calculations considering aquifer and aquitard deformation. Future land subsidence in the plain is predicted assuming different water pumping scenarios, and the results provide important information for land subsidence mitigation decision-making. 相似文献
8.
Kunasegaram Vijayakanthan Takemura Jiro 《Geotechnical and Geological Engineering》2022,40(6):2967-3005
Geotechnical and Geological Engineering - As a part of studies on cantilever type large-diameter steel tubular pipe retaining walls embedded into stiff ground, single pile lateral loading tests... 相似文献
9.
Contaminations in sediments by polycyclic aromatic hydrocarbons (PAHs) and alkylated PAHs were investigated at 44 sites in Osaka Bay, Japan. Concentrations of total PAHs and alkylated PAHs were in the range 6.40–7800 ng/g dry weights and 13.7–1700 ng/g dry weights, respectively. The PAH concentrations tended to be higher along the shoreline in the vicinities of big ports, industrialized areas, and densely populated regions such as the cities of Osaka and Kobe. The major sources appeared to be pyrogenic or both pyrogenic and petrogenic at most of the sites. PAH concentrations were remarkably high at a site near Kobe, where the concentrations of dibenzo(a,h)anthracene and benzo(g,h,i)perylene exceeded the effects-range-medium concentration and eight PAHs were above the corresponding effects-range-low concentrations. Those PAHs may have been derived from the great fire associated with the large earthquake in 1995. 相似文献
10.
Jiro Koyama Chie Imakado Seiichi Uno Takako Kuroda Shouichi Hara Takahiro Majima Hideyuki Shirota Nathaniel C. Añasco 《Marine pollution bulletin》2014
To assess risks of chemically-dispersed oil to marine organisms, oil concentrations in the water were simulated using a hypothetical spill accident in Tokyo Bay. Simulated oil concentrations were then compared with the short-term no-observed effect concentration (NOEC), 0.01 mg/L, obtained through toxicity tests using marine diatoms, amphipod and fish. Area of oil concentrations higher than the NOEC were compared with respect to use and non-use of dispersant. Results of the simulation show relatively faster dispersion near the mouth of the bay compared to its inner sections which is basically related to its stronger water currents. Interestingly, in the inner bay, a large area of chemically-dispersed oil has concentrations higher than the NOEC. It seems emulsifying oil by dispersant increases oil concentrations, which could lead to higher toxicity to aquatic organisms. When stronger winds occur, however, the difference in toxic areas between use and non-use of dispersant is quite small. 相似文献