A Study Of The Atmospheric Boundary Layer Using Radon And Air Pollutants As Tracers     

Toshio Kataoka  Eiji Yunoki  Mitsuo Shimizu  Tadashige Mori  Osamu Tsukamoto  Yukitaka Ohashi  Ken Sahashi  Toshihiko Maitani  Koh’ichi Miyashita  Toru Iwata  Yoko Fujikawa  Akira Kudo  Roger H. Shaw 《Boundary-Layer Meteorology》2001,101(2):131-156

Concentrations of radon ²²²Rn andair pollutants, meteorological parametersnear the surface and vertical profiles of meteorological elements were measured atUchio (Okayama City, Okayama Prefecture, Japan) 12 km north from the coast ofthe Inland Sea of Japan. In the nighttime, the ²²²Rn concentration increased in the case of weak winds, but did not increase as much in the case of moderate or strong winds, as had been expected. In the daytime, the ²²²Rn concentrationheld at a slightly higher than average level for the period from sunrise to about 1100 JST. It is considered that this phenomenon is due to a period of morning calm, that is, a transition period from land breeze to sea breeze.NO, which is sensitive to traffic volume,brought information concerning advection.Oxidant concentrations,which reflect the availability of sunlight,acted in the reverse manner to ²²²Rnconcentrations. Thus, a set of ²²²Rn and air pollutants could provide useful information regarding the local conditions of the atmospheric boundary layer.  相似文献   

Organochlorine and butyltin residues in deep-sea organisms collected from the western North Pacific,off-Tohoku,Japan   总被引：4，自引：0，他引：4  

de Brito AP  Takahashi S  Ueno D  Iwata H  Tanabe S  Kubodera T 《Marine pollution bulletin》2002,45(1-12):348-361

Organochlorine (OCs) and butyltin (BTs) residues were determined in deep-sea organisms collected from the western North Pacific, off-Tohoku, Japan. Among OCs, concentrations of polychlorinated biphenyls (PCBs) and DDTs (DDTs and its metabolites) were the highest in deep-sea organisms (maximum concentrations of 6700 and 13,000 ng/g lipid wt, respectively). Chlordane compounds (CHLs) were the next most abundant OCs, and hexachlorocyclohexanes (HCHs) and hexachlorobenzene (HCB) were the lowest. BTs were also detected at maximum concentrations of 570 ng/g wet wt. Concentrations of PCBs, CHLs and BTs in deep-sea organisms collected from the western North Pacific, off-Tohoku, were generally lower than those in deep-sea and shallow water organisms from Japanese coastal waters. On the other hand, considerable variations in the concentrations of OCs were found among deep-sea organisms analyzed. Several carnivorous fishes such as snubnosed eel, lanternshark and grenadiers accumulated some OCs such as PCBs, DDTs and CHLs at high concentrations of up to a few μg/g levels. In addition, the residue pattern of OCs and BTs in fishes showed a specific trend according to the sampling depth; higher concentrations of PCBs, DDTs and CHLs and lower concentrations of HCHs, HCB and BTs were found in fishes collected from greater depth (1000 m) compared to those from shallower waters. This trend is consistent with the results of our earlier study on mesopelagic myctophid fishes. Results of this study suggest vertical transport of hydrophobic OCs such as PCBs, DDTs and CHLs and its accumulation in benthic deep-sea organisms.  相似文献   

Late Paleozoic faults of the Altai region, Central Asia: tectonic pattern and model of formation   总被引：4，自引：0，他引：4  

M. M. Buslov  T. Watanabe  Y. Fujiwara  K. Iwata  L. V. Smirnova  I. Yu Safonova  N. N. Semakov  A. P. Kiryanova 《Journal of Asian Earth Sciences》2004,23(5):655-671

The present kinematic and dynamic analysis of large-scale strike-slip faults, which enabled the formation of a collage of Altai terranes as a result of two collisional events. The Late Devonian–Early Carboniferous collision of the Gondwana-derived Altai-Mongolian terrane and the Siberian continent resulted in the formation of the Charysh–Terekta system of dextral strike-slip faults and later the Kurai and Kuznetsk–Teletsk–Bashkauss sinistral strike-slip faults. The Late Carboniferous–Permian collision of the Siberian and Kazakhstan continents resulted in the formation of the Chara, Irtysh and North-East sinistral strike-slip zones. The age of deformation of both collisional events becomes younger toward the inner areas of the Siberian continent. In the same direction the amount of displacement of strike-slip faulting decreases from several thousand to several hundred kilometers. The width of the Late Paleozoic zone of deformation reaches 1500 km. These events deformed the accretion-collision continental margins and their primary paleogeographic pattern.  相似文献   

Energy dissipation behaviour of shear panels made of low yield steel     

Masayoshi Nakashima  Satoshi Iwai  Mamoru Iwata  Toru Takeuchi  Shinzo Konomi  Takashi Akazawa  Kazuhiro Saburi 《地震工程与结构动力学》1994,23(12):1299-1313

This paper presents the results of a pilot test conducted for evaluating the energy dissipation behaviour of shear panels made of low yield steel whose 0.2 per cent offset yield stress is 120 MPa. A total of six full-scale shear panels were tested with the loading condition, stiffener spacing, and magnitude of axial force as test variables. The shear panels tested yielded at a shear force that is approximately 1/3 of the yield shear force of equivalent shear panels made of common mild steel. Shear panels with proper stiffener arrangement exhibited stable hysteresis, thus ensuring large energy dissipation capacity. Sufficient strain hardening was observed in the shear panels tested, with their energy dissipation capacity about 1.5 times larger than that of an equivalent linear-elastic and perfect-plastic system. Plate buckling did not lead the shear panels to immediate degradation in their energy dissipation capacity. Post-buckling resistance was found to be a subject that requires further studies for quantifying the performance of shear panels made of low yield stress steel as hysteretic dampers.  相似文献   

Searching for novel CYP members using cDNA library from a minke whale liver     

Kim EY  Iwata H  Fujise Y  Tanabe S 《Marine environmental research》2004,58(2-5):495-498

The contaminant-induced cytochrome P450 (CYP) members in minke whale (Balaenoptera acutorostrata) can be potential biomarkers of the contaminant exposure and toxic effects. In this study, we constructed a cDNA library from the liver of minke whale from the North Pacific, and further screened a total of 6930 clones randomly selected in the library for the isolation of cDNA clones encoding novel members of CYP superfamily. The screening revealed the isolation of six novel CYP cDNA clones that are classified into CYP1A, CYP2C, CYP2E, CYP3A, CYP4, and CYP4A subfamilies. The BLAST homology search using the partial cDNA fragments of four CYP subfamilies (CYP1A, CYP2C, CYP2E and CYP4A) demonstrated that the minke whale CYPs were most closely related to pig CYPs (81-91%). Identification of multiple CYP genes in marine mammal species such as minke whale will provide new insights into the metabolic or toxicological functions of individual CYP members.  相似文献   

Identification of constitutive androstane receptor cDNA in northern fur seal (Callorhinus ursinus)     

Sakai H  Iwata H  Kim EY  Tanabe S  Baba N 《Marine environmental research》2004,58(2-5):107-111

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Surface circulation in Sagami Bay: the response to variations of the Kuroshio axis     

Shizuo Iwata  Masaji Matsuyama 《Journal of Oceanography》1989,45(5):310-320

In order to study the characteristics of the surface circulation in Sagami Bay, long-term current measurements were carried out at five moored stations during the period from October 1982 to January 1984. The majority of current patterns show the existence of a cyclonic eddy in the bay, while at times the direction of the circulation is reversed. When the Kuroshio current flows over the Izu-Ogasawara Ridge and approaches Sagami Bay, the current that passes through the Oshima-West Channel north of Oshima Island (COWC), has a strong clockwise flow, while the counterclockwise circulation in the bay becomes intensified. When the Kuroshio shifts southward off the shore, the COWC and the flow in the bay are weak or at times reverse their directions.  相似文献   

134Cs and 137Cs in the North Pacific Ocean derived from the March 2011 TEPCO Fukushima Dai-ichi Nuclear Power Plant accident,Japan. Part two: estimation of 134Cs and 137Cs inventories in the North Pacific Ocean     

Michio Aoyama  Mizuo Kajino  Taichu Y. Tanaka  Tsuyoshi Thomas Sekiyama  Daisuke Tsumune  Takaki Tsubono  Yasunori Hamajima  Yayoi Inomata  Toshitaka Gamo 《Journal of Oceanography》2016,72(1):67-76

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Arsenic species and their accumulation features in green turtles (Chelonia mydas)     

Agusa T  Takagi K  Iwata H  Tanabe S 《Marine pollution bulletin》2008,57(6-12):782-789

Total arsenic (As) and its compounds were determined in liver, kidney, muscle, and stomach contents of green turtles (Chelonia mydas). Total As concentrations in the muscle were higher than those in the kidney and liver. Arsenobetaine (AB) was the predominant compound in all the three tissues and its levels were positively correlated with total As concentrations. This indicates that AB greatly contributes to As accumulation in green turtles. Higher concentrations of remaining As in the sample after extraction were detected in the liver, implying that lipid-soluble or protein bound As compounds accumulate in the liver of green turtles. Total As levels in tissues showed significant negative correlations with standard carapace length. The size-dependence of As accumulation in green turtles may be related to their feeding habit, shifting from carnivore to herbivore at different growth stages. Concentrations of AB and dimethylarsinic acid (DMA) were low in the stomach contents but high in the tissues, implying bioaccumulation of these arsenicals in green turtles.  相似文献   

Validation of 3-D basin structure models for long-period ground motion simulation in the Osaka basin, western Japan     

Asako Iwaki  Tomotaka Iwata 《Journal of Seismology》2008,12(2):197-215

We studied the applicability of two types of existing three-dimensional (3-D) basin velocity structure models of the Osaka basin, western Japan for long-period ground motion simulations. We synthesized long-period (3–20 s) ground motions in the Osaka basin during a M6.5 earthquake that occurred near the hypothetical Tonankai earthquake source area, approximately 200 km from Osaka. The simulations were performed using a 3-D finite-difference method with nonuniform staggered grids using the two basin velocity structure models. To study the ground motion characteristics inside the basin, we evaluated the wave field inside the basin using the transfer functions derived from the synthetics at the basin and a reference rock site outside the basin. The synthetic waveforms at the basin site were obtained by a convolution of the calculated transfer function and the observed waveform at the reference rock site. First, we estimated the appropriate Q values for the sediment layers. Assuming that the Q value depends on the S wave velocity V _S and period T, it was set to Q = (1/3V _S)(T ₀/T) where V _S is in m/s and the reference period T ₀ is 3.0 s. Second, we compared the synthetics and the observations using waveforms and pseudovelocity response spectra, together with a comparison of the velocity structures of the two basin models. We also introduced a goodness-of-fit factor to the pseudovelocity response spectra as an objective index. The synthetics of both the models reproduced the observations reasonably well at most of the stations in the central part the basin. At some stations, however, especially where the bedrock depth varies sharply, there were noticeable discrepancies in the simulation results of the models, and the synthetics did not accurately reproduce the observation. Our results indicate that the superiority of one model over the other cannot be determined and that an improvement in the basin velocity structure models based on simulation studies is required, especially along the basin edges. We also conclude that our transfer function method can be used to examine the applicability of the basin velocity structure models for long-period ground motion simulations.  相似文献