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71.
Nobuo Sugimoto Atsushi Shimizu Ichiro Matsui Itsushi Uno Kimio Arao Xuhui Dong Shuli Zhao Jun Zhou Choo-Hie Lee 《Water, Air, & Soil Pollution: Focus》2005,5(3-6):145-157
We have conducted dust observations at a number of locations including Beijing, Hefei, Suwon, Fukue, Nagasaki, Tsukuba, and
Sapporo using automated two-wavelength polarization lidars o study Asian dust phenomena, including generation, transport,
and change during transport. We developed a method using the depolarization ratio for estimating the contributions of Asian
dust and spherical air-pollution aerosols in observed aerosol mixtures. We analyzed the dust profiles statistically to derive
climatological characteristics and year-on-year variations. We also studied dust source and transport path for each dust event
using the regional chemical transport model CFORS. The statistical analysis clearly demonstrated the year-on-year variation
of dust phenomena and the characteristics depending on the locations of the observational sites. Most major dust events in
2001 and 2002 originated in Inner Mongolia and/or Mongolia at the southern edge of a low-pressure area located in Siberia
and were transported by strong westerlies. In 2003, the typical meteorological pattern for heavy dust cases accompanying a
strong low in Siberia was not seen, except for one case in April. Furthermore, the lidar observation in Beijing suggests that
less dust was generated in the source regions in Inner Mongolia and/or Mongolia, probably due to higher precipitation in 2003. 相似文献
72.
A. Yano M. Ogura A. Sato Y. Sakaki Y. Shimizu N. Baba K. Nagasawa 《Marine Biology》1997,129(3):523-530
To investigate the role of magnetic compass orientation in oceanic migrating chum salmon, Oncorhynchus keta, an ultrasonic telemetry study was carried out in the western North Pacific off the coast of Kushiro, Hokkaido. Four salmon
were fitted with a tag which generated an artificial magnetic field and modified the geomagnetic field around the head of
the fish. Initially, the free-ranging salmon with stomach-implanted ultrasonic transmitters were tracked for a period of several
hours before the magnetic field was altered for a period of 16 h. The generator produced an alternating magnetic field intensity
of about 6 gauss, with polarity which reversed every 11.25 min. There was no observable effect on the horizontal and vertical
movements of the salmon when the magnetic field was modified. However, it was noted that salmon slowed their swimming speed
significantly before changing direction, regardless of whether the fish were swimming under the normal geomagnetic field or
whether they were swimming under the modified field.
Received: 6 April 1997 / Accepted: 29 April 1997 相似文献
73.
74.
Larvae of the marine cheilostomatid bryozoan Bugula neritina (L.) were prevented from settling for 1, 4 and 8 h by mechanical agitation, following which settlement and metamorphosis
success were examined. Settlement rates were significantly affected by swimming time, which decreased from 100% after 2 h
to 93.7 ± 4.3% after 8 h. Similarly, metamorphosis to the feeding ancestrula was significantly impaired following a swimming
time of 8 h, declining from 93.7 ± 4.3% after 1 h to 65.9 ± 7.0% after 8 h. The resultant colonies grew well for the first
3 wk, following which time, growth patterns became erratic. Growth rate was in all cases highly variable, and did not correlate
with enforced swimming times. Larval protein composition was examined after 1, 4 and 8 h swimming time, and post-larval composition
1, 2, 5, 24 and 48 h after settlement using sodium-dodecyl-sulphate polyacrylamide-gel electrophoresis (SDS-PAGE). Individual
protein content was measured using a densitometer. Larvae did not consume protein during swimming, however a protein measuring
170 kdaltons was consumed during metamorphosis. These results are discussed in the context of larval settlement and energetics.
Received: 19 July 1998 / Accepted: 3 December 1998 相似文献
75.
Hiroshi Shimizu Manai Tsuzuki Yasuo Yamazaki A. Koichi Hayashi 《Journal of Loss Prevention in the Process Industries》2001,14(6):603-608
The study of extinguishment using water mist has been motivated due to the phase-out of the use of halens and the search for alternative means that preserve all of the benefits of a clean total flooding agent without adverse environmental impact. With the numerical simulation, we analyzed a gas–liquid two-phase problem including water (liquid), air and methane (gas) using Eulerian equations for the liquid phase and the full Navier–Stokes equations for the gas phase. Gaseous mass, momentum and energy equations are integrated simultaneously by a Harten–Yee explicit non-MUSCL modified-flux type TVD scheme for the convective terms and a central difference scheme for the viscous terms. Liquid phase conservation equations are solved with an application of a flux-vector-splitting scheme. In the experiments in an open room (500×500×500 mm) we observed an interaction of the diffusion flame with the water mists. The results show remarkable flame quenching and a good agreement between the numerical and experimental results. 相似文献
76.
本研究以太平洋附近具有典型海岸地形地貌的3.2km2的区域为调查研究对象。首先,通过调查设置在河流上的5处调查点的河流水位及河水铅直方向电导率,掌握了感潮河流海水上朔的规律。其次,通过调查设置在区域内的26口调查井在满潮和干潮时的地下水位,推断出了潮汐的涨落及感潮河流和地下水流动方向的关系。此外,对与海岸垂直的断面和平行的断面上的10口调查井的调查结果显示,同一位置、不同季节其地下水面波动的特点不同;不同的调查井,因所处位置的不同及与海岸、感潮河流距离的不同,其地下水面波动的振幅及其与潮汐波动的位相差也不同。 相似文献
77.
Akata N Hasegawa H Kawabata H Chikuchi Y Sato T Ohtsuka Y Kondo K Hisamatsu S 《Journal of environmental radioactivity》2007,95(1):1-9
Biweekly atmospheric depositions of (137)Cs were measured in Rokkasho, Aomori, Japan from March 2000 to March 2006 to study recent (137)Cs deposition. Although the deposition level was generally lower than the detectable limit, deposition samples collected in spring occasionally had measurable levels of (137)Cs. The annual (137)Cs deposition from 2001 to 2005 was 0.04-0.69 Bq m(-2) with a mean value of 0.27 Bq m(-2). Depositions of insoluble Al, Fe and Ti were strongly correlated with the (137)Cs deposition, suggesting that suspension of soil particles was the main source of the recent (137)Cs deposition. Asian dust events were coincident with some of the significant (137)Cs depositions in spring. It was found that the ratios of (137)Cs/Al and Fe/Al could be used as indices for discriminating Asian dust from suspension of the local surface soil. Backward trajectory analysis suggested southern Mongolian and northeastern China regions as sources of the significant (137)Cs depositions. 相似文献
78.
Shimizu Hiroyuki Matsuura Norihisa Gu TingTing Tsuritani Takashi Okamoto Minoru Yamamoto-Ikemoto Ryoko 《Journal of Material Cycles and Waste Management》2022,24(6):2341-2352
Journal of Material Cycles and Waste Management - Improving the solid-state digestion of food waste (FW) is important for recovering energy and utilizing the digested residue as fertilizer. Herein,... 相似文献
79.
Measures of niche overlap are used to assess the similarity or dissimilarity of two populations. Matusita's measure is one of commonly used niche overlap measures. We consider the problem of estimating Matusita's measure when samples are from multivariate normal distributions with unknown mean vectors and covariance matrices. Asymptotic variances and biases of Matusita's measure estimates are derived and bias reduction methods are proposed. Simulation results are shown to illustrate characteristics of the estimates and bias reduction methods. 相似文献
80.
Evaluating stream water quality through land use analysis in two grassland catchments: impact of wetlands on stream nitrogen concentration 总被引:2,自引:0,他引:2
Hayakawa A Shimizu M Woli KP Kuramochi K Hatano R 《Journal of environmental quality》2006,35(2):617-627
We evaluated the impacts of natural wetlands and various land uses on stream nitrogen concentration in two grassland-dominated catchments in eastern Hokkaido, Japan. Analyzing land use types in drainage basins, measuring denitrification potential of its soil, and water sampling in all seasons of 2003 were performed. Results showed a highly significant positive correlation between the concentration of stream NO3-N and the proportion of upland area in drainage basins in both catchments. The regression slope, which we assumed to reflect the impact on water quality, was 24% lower for the Akkeshi catchment (0.012 +/- 0.001) than for the Shibetsu catchment (0.016 +/- 0.001). In the Akkeshi catchment, there was a significant negative correlation between the proportion of wetlands in the drainage basins and stream NO3-N concentration. Stream dissolved organic nitrogen (DON) and carbon (DOC) concentrations were significantly higher in the Akkeshi catchment. Upland and urban land uses were strongly linked to increases in in-stream N concentrations in both catchments, whereas wetlands and forests tended to mitigate water quality degradation. The denitrification potential of the soils was highest in wetlands, medium in riparian forests, and lowest in grasslands; and was significant in wetlands and riparian forests in the Akkeshi catchment. The solubility of soil organic carbon (SOC) and soil moisture tended to determine the denitrification potential. These results indicate that the water environment within the catchments, which influences denitrification potential and soil organic matter content, could have caused the difference in stream water quality between the two catchments. 相似文献