SDSS J131339.98+515128.3: a new gravitationally lensed quasar selected based on near-infrared excess     

Eran O. Ofek  Masamune Oguri  Neal Jackson  Naohisa Inada  Issha Kayo 《Monthly notices of the Royal Astronomical Society》2007,382(1):412-418

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Dimensions of long‐nosed Chimaera Harriotta Raleighana from New Zealand     

J. A. F. Garrick  T. Inada 《新西兰海洋与淡水研究杂志》2013,47(2):159-167

The proportional dimensions of 66 adult specimens of Harriotta raleighana Goode & Bean, 1895 (Holocephali: Rhinochimacridae) from New Zealand are summarised; in both sexes there is considerable variation in proportions. Within the size range of the sample, the snout region of males is proportionately longer than that of females, and growth of the snout is negatively allometric in both sexes. Meagre data suggest that similar sexual dimorphism and allometry occur in North Atlantic specimens, though very large and very small specimens do not fit an extrapolation of the New Zealand data. None of the New Zealand males has the snout tip upturned and armed with large rounded knobs as described for North Atlantic males.  相似文献   

Fast shear behavior of granular materials in ring-shear tests and implications for rapid landslides   总被引：1，自引：0，他引：1  

Yao Jiang  Gonghui Wang  Toshitaka Kamai 《Acta Geotechnica》2017,12(3):645-655

The high mobility of rapid landslides is one of the most important subjects of both theoretical and practical interest to engineers and scientists. The idea that ultralow resistance could explain the high mobility inspires researchers to examine the shear behavior of granular materials under a wide range of conditions, but the response of granular materials to fast loading rates is largely unknown. The motivation for this study was to examine several fundamental issues of particle properties and mechanical conditions on the fast shear behavior of granular materials. Two granular materials were studied in the oven-dried state and were sheared by employing a ring-shear apparatus. Results indicated that angular particles (silica sand) had higher shear strength parameters than spherical particles (glass beads). In addition, the dilative process was observed during shearing, which depended on normal stress and particle shape. A slightly negative shear-rate effect on shear strength was observed for both granular materials under a certain range of shear rates. Furthermore, cumulative shear displacement had a significant effect on the degree of particle crushing. Fast ring-shear tests also revealed that shear rate had a slightly negative effect on particle crushing. Based on these experimental results, the possible applications of dynamic grain fragmentation theory to assess the high mobility of rapid landsliding phenomena were discussed. It was indicated that the magnitude and release rate of elastic strain energy generated by grain fragmentation played important roles on the dynamic process of landslide mobility.  相似文献   

APPLICATION OF MEM SPECTRAL ESTIMATION TO MU RADAR OBSERVATION   总被引：1，自引：0，他引：1       下载免费PDF全文

Li Wei  L&#;Daren  Shoichiro Fukao  Mamoru Yamamoto  Toshitaka Tsu  Susumu Kato 《Acta Meteorologica Sinica》1991,5(3):293-298

Preliminary results of the wind velocity estimation using the Maximum Entropy Method (MEM) to MUradar observation data sets are presented. The comparison of the results from the periodogram method and theMEM shows that the MEM estimation is reliable, and has higher accuracy, resolution and detectability than theestimation from periodogram method. The high accuracy power spectrum obtained by the MEM is veryuseful to studying the atmospheric turbulence structure. However. the MEM needs the longer computingtime for obtaining the high accuracy spectrum. Particularly, the estimation of MEM will bring serious devia-tion at lower signal-to-noise ratio.  相似文献   

Seasonal variation of atmospheric 210Pb and Al in the western North Pacific region     

Shizuo Tsunogai  Takayoshi Kurata  Toshitaka Suzuki  Khchiro Yokota 《Journal of Atmospheric Chemistry》1988,7(4):389-407

The atmospheric concentration of ²¹⁰Pb was determined for two years at six stations in the western North Pacific region. The following results were obtained and discussed by comparing them with those of Al. The atmospheric concentration of ²¹⁰Pb varied widely from week to week, but the degree of variation was about a half that of Al. Contrary to Al, the year-to-year variation of ²¹⁰Pb was not pronounced and its seasonal variation was well expressed by a sine curve. The ²¹⁰Pb concentration did not show a marked latitudinal variation and its base-line concentration was high in the surface air over the North Pacific. These suggest that atmospheric ²¹⁰Pb has a longer residence time, due to its transportation through higher altitudes and deposits much more evenly onto the Earth's surface and the ocean, as compared with Al in mineral dust which is larger in size in the source region.  相似文献   

Full-correlation analysis of turbulent scattering layers in the mesosphere observed by the MU radar     

Mamoru Yamamoto  Toru Sato  Toshitaka Tsuda  Shoichiro Fukao  Susumu Kato 《Pure and Applied Geophysics》1989,130(2-3):605-616

We have applied a full-correlation analysis technique to the echo power fluctuations observed by the MU radar (35°N, 136°E), and analyzed the horizontal structure of the scattering pattern in the mesosphere as well as their horizontal motions. The velocity of the scattering pattern did not agree with the background wind velocity, but was associated with the horizontal propagating direction of a saturated inertia gravity wave identified in the wind field. The length of the long axis of the characteristic ellipse of the scattering pattern was approximately 50 km, and the direction was almost perpendicular to the propagating direction of the wave. The correlation time of the scattering pattern was approximately 700 s, which is much longer than the lifetime of the isolated turbulence itself. This implies that the observed scattering pattern is associated with a region where the saturated inertia gravity wave generates turbulence.  相似文献   

Diurnal variations of the planetary boundary layer observed with anL-band clear-air doppler radar     

Hiroyuki Hashiguchi  Manabu D. Yamanaka  Toshitaka Tsuda  Mamoru Yamamoto  Takuji Nakamura  Tatsuhiro Adachi  Shoichiro Fukao  Toru Sato  Daniel L. Tobing 《Boundary-Layer Meteorology》1995,74(4):419-424

Based on continuous observations of the planetary boundary layer (PBL) with anL-band (1357.5 MHz) boundary-layer radar (BLR) at a hilly location in Japan, we have discovered that on clear days, a thin enhanced echo layer corresponding to the top of the PBL (or mixed layer) appeared at about 500 m height in the morning and ascended to about 1500 m in the afternoon. Strong upward velocities were observed below the echo layer (or inside the PBL), reaching 1500 m in the afternoon.  相似文献   

Seismic Retrofit of Gravity Retaining Walls for Residential Fills Using Ground Anchors     

Aurelian Catalin Trandafir  Toshitaka Kamai  Roy Carl Sidle  Mihail Popescu 《Geotechnical and Geological Engineering》2007,25(6):679-691

Failure of several gravity retaining walls in residential areas built on reclaimed land, during the October 23, 2004 Chuetsu earthquake in Niigata Prefecture, Japan, determined the authorities to consider the seismic retrofit of the walls in order to mitigate future similar disasters in the urban environment. This study addresses the effectiveness of ground anchors in improving the seismic performance of such retaining structures through a sliding block analysis of the seismic response of an anchored gravity retaining wall supporting a dry homogeneous fill slope subject to horizontal ground shaking. Sliding failure along the base of the wall and translational failure along a planar slip surface of the active wedge within the fill material behind the wall were considered in the formulation, whereas the anchor load was taken as a line load acting on the face of the gravity retaining wall. The effects of magnitude and orientation of anchor load on the yield acceleration of the wall-backfill system and seismically induced wall displacements were examined. It was found that for the same anchor orientation, the yield acceleration increases in a quasi-linear manner with increasing the anchor load, whereas an anchor load of a given magnitude acting at various orientations produces essentially identical yield accelerations. On the other hand, the computed earthquake-induced permanent displacements of the anchored gravity retaining wall decrease exponentially with increasing magnitude of anchor load. Additionally, the influence of backfill strength properties (e.g., internal friction angle) on the seismic wall displacement appears to diminish considerably for the anchored gravity retaining wall. A dynamic displacement analysis conducted for the anchored gravity retaining wall subjected to various seismic waveforms scaled to the same peak earthquake acceleration revealed a good correlation between the calculated permanent wall displacements and the Arias intensity parameter characterizing the input accelerogram.  相似文献   

Abyssal circulation in the Japan Sea     

Gamo  Toshitaka  Horibe  Yoshio 《Journal of Oceanography》1983,39(5):220-230

Journal of Oceanography - The water below a depth of 1,000 m in the Japan Sea was found to consist of two water masses, the upper layer (the Deep Water) and the lower layer (the Bottom Water). The...  相似文献   

Seasonal and areal variation of continental aerosol in the surface air over the western North Pacific region   总被引：1，自引：0，他引：1  

Shizuo Tsunogai  Toshitaka Suzuki  Takayoshi Kurata  Mitsuo Uematsu 《Journal of Oceanography》1985,41(6):427-434

Weekly aerosol samples were collected for two years from 1981 at six stations in the western North Pacific region. The samples were analyzed for aluminum to determine the mineral dust concentration in the air. By combining our data with observations in the central and eastern North Pacific by a US research group, the following results and conclusions have been obtained. Spring peaks in atmospheric mineral dust were observed at all the stations accompanied byKosa episodes (hazes due to mineral dust of Chinese origin). The spring peaks, however, varied from year to year. The mean concentration of mineral dust depends not only on the distance from the Asian coast but also on the latitude of the sampling station. The half-decrease distance of the atmospheric mineral dust turned out to be 500–600 km for all latitudes in the western North Pacific. This indicates that the rate of deposition of mineral dust in the western North Pacific is much larger than that in the central and eastern North Pacific.  相似文献