Preliminary report on radionuclide concentrations in the bottom waters at the entrance of Wakasa Bay with special reference to the Japan Sea Proper Water     

F. Kasamatsu  Y. Ueda  T. Tomizawa  N. Nonaka  Y. Nagaya 《Journal of Oceanography》1994,50(5):589-598

Marked fluctuation of concentrations of⁹⁰Sr and¹³⁷Cs was observed in the bottom waters at the entrance of Wakasa Bay during 1987–1992, and the cause was investigated. The concentrations of⁹⁰Sr and¹³⁷Cs in the bottom waters were significantly low when the upper level of the Japan Sea Proper Water (JSPW) was high and covered the sampling depth, but high when the upper level of the JSPW was low. The cause of the fluctuation observed in the bottom waters is, therefore, suggested to be the vertical fluctuation of the upper level of the JSPW on the shelf slope, which has been little described before.  相似文献   

The chemical composition and nickel,cobalt, copper,zinc and lead contents of Nanao Bay sediments     

Yoshikazu Yamamoto  Yukitaka Tanaka  Shunzo Ueda 《Journal of Oceanography》1977,33(5):242-246

The contents of major and some of the minor elements, nickel, cobalt, copper, zinc and lead were studied on sediments collected from three inlets of Nanao Bay located at eastern side of Noto Peninsula. Little variation was found on the average contents of silicon, iron, titanium, aluminum, manganese, magnesium and potassium among the sediments of West, South and North Bays in Nanao Bay. Whereas significant difference was found on the contents of calcium, chlorine, sulfur and nitrogen among sediments of three bays.As to the minor elements, the average contents of nickel (20±5 ppm), cobalt (5±1 ppm), copper (18±5 ppm) and lead (17±8 ppm) are relatively low but zinc content is high in these sediments comparing with those of coastal deposit around Japan Island. From the results obtained here, it became clear that no environmental contamination of nickel, cobalt, copper and lead, and a little organic pollution were found in Nanao Bay sediments.  相似文献   

Managing and bridging communities in temporary housing: case of the Great East Japan Earthquake and Tsunami in Kesennuma City,Japan     

Yasutaka Ueda  Rajib Shaw 《Natural Hazards》2016,80(1):567-587

  相似文献   

Sulfur isotope study of Quaternary volcanic rocks from the Japanese Islands Arc     

Akira Ueda  Hitoshi Sakai 《Geochimica et cosmochimica acta》1984,48(9):1837-1848

The sulfide and sulfate contents and their δ³⁴S values were determined in Quaternary volcanic rocks from the Japanese Islands Arc. The total sulfur contents are much lower (less than 40 ppm) and the δ³⁴S values are higher (+4.4 ± 2.1) than those of ocean-floor basalts (800 ± 100 ppm and +0.8 ± 0.5, respectively; Moore and Fabbi, 1971; Sakaiet al., 1982). Lateral variations of both sulfur content and δ³⁴S values were observed in the four volcanic belts in Japan. In the Northeast Japan belt, the sulfur content (30 ± 10 ppm) of the rocks in the inner zone (the Japan Sea side) is 3 to 5 times that in the outer zone (the Pacific side), although the δ³⁴S values of the two zones are almost the same (+4.3 ± 1.0). The δ³⁴S values for the two belts in West Japan are on the average 2%. higher than those of East Japan.This study suggests that the primary magmas that formed the island arc volcanic rocks are initially depleted in sulfur (<120 ppm) and enriched in ³⁴S ($\text{δ}{}^{34}\text{S: +5 ～ +7}$) compared to ocean-floor tholeiitic basalts which formed at mantle under oceanic region. This indicates that the upper-mantle is heterogeneous in sulfur content and isotope composition.  相似文献   

ASCA observations of the Galactic superluminal sources GRO J1655–40 and GRS 1915+105     

Kazutaka Yamaoka  Yoshihiro Ueda  Hajime Inoue  Fumiaki Nagase  Ken Ebisawa  Taro Kotani  Yasuo Tanaka 《Astrophysics and Space Science》2001,276(1):19-22

We summarize the ASCA observations of the two Galactic superluminal sources GRO J1655–40 and GRS 1915+105, focusing on theabsorption line features.The high spectroscopic capability of ASCA enabled us to detectiron-K absorption line features from both objects. This is direct evidence for the presence of highly ionized plasma in a non-spherical configuration around a black hole, and is considered to be a unique signature of superluminal jet systems. The candidate of the line-absorber would be a part of an accretion disk at a distance of 10^9-11 cm from the central X-ray source.  相似文献   

Fast Oxidation Reaction of Nitrite by Dissolved Oxygen in the Freezing Process in the Tropospheric Aqueous Phase     

Norimichi Takenaka  Tohru Daimon  Akihiro Ueda  Keiichi Sato  Masaru Kitano  Hiroshi Bandow  Yasuaki Maeda 《Journal of Atmospheric Chemistry》1998,29(2):135-150

Nitrite oxidation in the tropospheric aqueous phase by freezing was evaluated by freezing a field sample. Nitrite oxidation by dissolved oxygen in the freezing process is much faster than by other oxidation processes, such as reactions with ozone, hydrogen peroxide or dissolved oxygen in an aqueous solution at pHs 3 to –6. At pH 4.5 and 25°C, the lifetime of nitrite in the aqueous phase is ca. 1 hr in oxidation by ozone (6×10^-10 mol dm^-3), ca. 10 hr in oxidation by H₂O₂ (2×10^-4 mol dm^-3), and 7.5 hr (Fischer and Warneck, 1996) in photodissociation at midday in summer. Under the same conditions at a temperature below 0°C, the lifetime of nitrite in the freezing process is estimated as ca. 2 sec when the droplets are frozen within a second. The reaction by freezing is affected by the presence of salts, such as NaCl or KCl, or orgnaic compounds, such as methanol or acetone. The results of freezing a field rain or fog sample showed that nitrite oxidation proceeds below pH 6, and the conversion ratio of nitrate from nitrite increases with decreasing pH. The oxidation of nitrite by freezing was also observed in freezing fog particles generated by an ultrasonic humidifier. The ratios of the concentrations of ions in the winter sample to those in the summer sample (or those in the fog sample) were almost the same values. However, the concentration of nitrite in the winter sample was lower than that estimated by the ratios of other ions. From the present study, it seems that the freezing process plays an important role in the nitrite sink process in the tropospheric aqueous phase.  相似文献   

Evaluation of failure of slopes with shaking-induced cracks in response to rainfall     

Xu  Jiawei  Ueda  Kyohei  Uzuoka  Ryosuke 《Landslides》2022,19(1):119-136

Landslides - Centrifuge model tests on slopes subject to shaking and rainfall have been performed to examine the response of slopes with shaking-induced cracks to subsequent rainfall and evaluate...  相似文献   

Global shearing modes of galactic disks     

Masanori Iye  Tatsuo Ueda  Masafumi Noguchi  Shinko Aoki 《Astrophysics and Space Science》1983,89(2):363-376

A new scheme has been devised to calculate discrete unstable global shearing spiral modes of gaseous disk models of galaxies. The scheme makes use of the Legendre expansion of eigen functions and the problem of stability analysis is reduced to an eigenvalue problem of an infinite matrix. The spiral patterns of these shearing wave solutions of linearized equations change their form in the course of time due to the differential rotation of the equilibrium disk. These shearing wave solutions are presumed to have intermediate characteristics between so-called density-waves and material arms. Comparison between these shearing modes and the non-shearing normal modes for a series of disk models is presented.  相似文献   

Shenandoah Watershed Study-Virginia Trout Stream Sensitivity Study (SWAS-VTSSS): Stream water quality and hydrologic monitoring data for mid-Appalachian headwater streams     

Ami L. Riscassi  Todd M. Scanlon  Suzanne W. Maben  James N. Galloway 《水文研究》2021,35(4):e14164

The Shenandoah Watershed Study (established in 1979) and the Virginia Trout Stream Sensitivity Study (established in 1987) serve to increase understanding of hydrological and biogeochemical changes in western Virginia mountain streams that occur in response to acidic deposition and other ecosystem stressors. The SWAS-VTSSS program has evolved over its 40+ year history to consist of a temporally robust and spatially stratified monitoring framework. Currently stream water is sampled for water quality bi-hourly during high-flow events at three sites and weekly at four sites within Shenandoah National Park (SHEN), and quarterly at 72 sites and on an approximately decadal frequency at ~450 sites within the wider western Virginia Appalachian region. Stream water is evaluated for pH, acid neutralizing capacity (ANC), base cations (calcium, magnesium, sodium and potassium ion), acid anions (sulphate, nitrate and chloride), silica, ammonium, and conductivity with a subset of samples evaluated for monomeric aluminium and dissolved organic carbon. Hourly stream discharge (four sites) and in-situ measurements of conductivity, water and air temperature (three sites) are also measured within SHEN. Here we provide an overview and timeline of the SWAS-VTSSS stream water monitoring program, summarize the field and laboratory methods, describe the water chemistry and hydrologic data sets, and document major watershed disturbances that have occurred during the program history. Website links and instructions are provided to access the stream chemistry and time-series monitoring data in open-access federal databases. The purpose of this publication is to promote awareness of these unique, long-term data sets for wider use in catchment studies. The water chemistry and hydrologic data can be used to investigate a wide range of biogeochemical research questions and provide key inputs for models of these headwater stream ecosystems. SWAS-VTSSS is an ongoing program and quality assured data sets are uploaded to the databases annually.  相似文献   

Supersonic jet formation and propagation in x-pinches     

D. M. Haas  S. C. Bott  J. Kim  D. A. Mariscal  R. E. Madden  Y. Eshaq  U. Ueda  G. Collins IV  K. Gunasekera  F. N. Beg  J. P. Chittenden  N. Niasse  C. A. Jennings 《Astrophysics and Space Science》2011,336(1):33-40

Observations of supersonic jet propagation in low-current x-pinches are reported. X-pinches comprising of four 7.5 ??m diameter tungsten wires were driven by an 80 kA, 50 ns current pulse from a compact pulser. Coronal plasma surrounding the wire cores was accelerated perpendicular to their surface due to the global J×B force, and traveled toward the axis of the x-pinch to form an axially propagating jet. These jets moved towards the electrodes and, late in time (??150 ns), were observed to propagate well above the anode with a velocity of 3.3±0.6×10⁴ m/s. Tungsten jets remained collimated at distances of up to 16 mm from the cross point, and an estimate of the local sound speed gives a Mach number of ??6. This is the first demonstration that supersonic plasma jets can be produced using x-pinches with such a small, low current pulser. Experimental data compares well to three-dimensional simulations using the GORGON resistive MHD code, and possible scaling to astrophysical jets is discussed.  相似文献