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1.
The content of selenium and its chemical form in sea water 总被引：1，自引：0，他引：1
By using the new fluorometric method of determination of the total selenium ( Se), Se (IV) and Se (VI), the content of selenium in sea weter was determined in the western North Pacific. Results showed that the content of Se in surface water ranged from 0.06 to 0.12g l–1, while in deeper layers, the content increased to 0.20g l–1. It was found that Se (IV) showed rather uniform distribution with depth, while Se (VI) increased with depth to about three times that in the surface. The ratio of Se (IV) to the Se ranged from 0.5 to 0.8 in the surface and 0.4 to 0.6 in the deep. The coexistence of the hexa- and tetravalent ions of selenium was confirmed both in surface and deep layers. Some results of observations on the content of selenium in the coastal areas of Japan were also reported. 相似文献
2.
A new method of determination of selenium and separation of Se(IV) and Se(VI) in sea water is described. The selenium is determined by fluorometric method using Se-DAN complex in cyclohexane media. Prior to the fluorometric determination, Se(IV) is separated from sea water by means of Se(IV)-DDTC complex which is adsorbed on the macroreticular resin. As to the separation of the total selenium from sea water sample, the reduction and coprecipitation method is used. Se(VI) is determined with the same method as used for the total selenium after the separation of Se(IV). The average recoveries are 92.5±1.3% for Se(IV) and 97.4±0.9% for Se. The standard deviation of analytical results is below 10%. 相似文献
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Carbon isotopic fractionation during the air/sea exchange process is not fully understood at present. Information on the equilibrium and kinetic fractionation factors is an essential requirement, together with the value of the CO2 partial pressure, for understanding the carbon cycle in the atmosphere and marine environments. Using a specially designed countercurrent equilibrator system, the fractionation factors between gaseous CO2 and dissolved inorganic carbon in sea water were determined under both kinetic and equilibrium conditions. The following results were obtained: kinetic fractionation factor for air to sea (αas) is 0.998 at 288.2 K; kinetic fractionation factor for sea to air (αsa) is 0.990; equilibrium fractionation factor (αeq) is 0.991 at pH = 8.3 and 288.2 K. From these results, the carbon isotopic ratio of CO2 passed through the air/ sea interface is estimated to be about ?10 %. for air to sea and ?8 %. for sea to air when CO2 exchange takes place between air (δ13C = ?8 %.) and surface sea water (δ13C = 2 %.) at 288.2 K. 相似文献
4.
Thorium isotopes in the airborne dust collected at Tsukuba Science City in Japan from January 1981 to December 1982 show clear seasonal variations. Especially228Th in the airborne particles have a typical maximum cincentration between February and April, which is about an order of magnitude higher than during the remainder of the year. According to the result of size distribution of thorium isotope-bearing particles in the air, about 53% of228Th is associated with the particles less than 1.6 μm aerodynamic diameter. These results reveal that228Th in the airborne particles is present in fine soily matters originating from the East Asian deserts. 相似文献
5.
Arata Sugimura Tokihiko Matsuda Kiyotaka Chinzei Kazuaki Nakamura 《Bulletin of Volcanology》1963,26(1):125-140
The late Cenozoic orogeny in Japan is briefly reviewed. Amounts of volcanic materials in the three periods of the orogeny are estimated at: early Neogene 150 × 103 km3 (mafic 40 %, salic 60 %), middle and late Neogene 20 × 103 km3 (mafic 70 %, salic 30 %), Quaternary 5 × 103 km3 (mafic 80 %, salic 20 %). The largest volume per unit time is in the early Neogene, and the smallest in the middle and late Neogene. Volume per unit area becomes larger towards the southeastern margin or «front» of the volcanic belt. Thermal energy transported by volcanic materials is compared with the terrestrial heat flow in the belt. 相似文献
6.
Juan C. Tokeshi Madan B. Karkee Yoshihiro Sugimura 《Soil Dynamics and Earthquake Engineering》2006,26(2-4):163-174
The paper utilizes previously developed microtremor simulation technique to evaluate the reliability of Rayleigh wave dispersion curve estimated by f–k spectral analysis of microtremor array measurement. The simulated microtremors are obtained for a fictitious (TEST) site. Attempt is also made to obtain the dispersion curve for two real sites (OHDATE and SKC) by inverse analysis of the microtremor array measurement using f–k spectra method. The estimated dispersion curve from simulated microtremors (TEST site) compares well with the theoretical dispersion curve, demonstrating the reliability of f–k spectra method and indicating that the estimated dispersion curve from microtremor measurements could be adequately used as the target for inverse analysis purposes. It is also demonstrated that the dispersion curve from microtremor measurements can be utilized to estimate the soil profile at OHDATE and SKC sites by inverse analysis. Results show that the theoretical dispersion curve of the fundamental mode of Rayleigh wave after the end of inverse analysis are in good agreement with the dispersion curve obtained by f–k spectral analysis of microtremor array measurement. 相似文献
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Normal fault growth and linkage in the Gediz (Alaşehir) Graben,Western Turkey,revealed by transient river long‐profiles and slope‐break knickpoints 
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下载免费PDF全文 Emiko Kent Sarah J. Boulton Alexander C. Whittaker Iain S. Stewart M. Cihat Alçiçek 《地球表面变化过程与地形》2017,42(5):836-852
The Gediz (Ala?ehir) Graben is located in the highly tectonically active and seismogenic region of Western Turkey. The rivers upstream of the normal fault‐bounded graben each contain a non‐lithologic knickpoint, including those that drain through inferred fault segment boundaries. Knickpoint heights measured vertically from the fault scale with footwall relief and documented fault throw (vertical displacement). Consequently, we deduce these knickpoints were initiated by an increase in slip rate on the basin‐bounding fault, driven by linkage of the three main fault segments of the high‐angle graben bounding fault array. Fault interaction theory and ratios of channel steepness suggest that the slip rate enhancement factor on linkage was a factor of 3. We combine this information with geomorphic and structural constraints to estimate that linkage took place between 0.6 Ma and 1 Ma. Calculated pre‐ and post‐linkage throw rates are 0.6 and 2 mm/yr respectively. Maximum knickpoint retreat rates upstream of the faults range from 4.5 to 28 mm/yr, faster than for similar catchments upstream of normal faults in the Central Apennines and the Hatay Graben of Turkey, and implying a fluvial landscape response time of 1.6 to 2.7 Myr. We explore the relative controls of drainage area and precipitation on these retreat rates, and conclude that while climate variation and fault throw rate partially explain the variations seen, lithology remains a potentially important but poorly characterised variable. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
9.
Uno S Tanaka H Miki S Kokushi E Ito K Yamamoto M Koyama J 《Marine pollution bulletin》2011,63(5-12):477-481
This paper reports for the first time the detection and occurrence of nitroarenes (NPAHs) in marine organisms. Mussels and oysters collected from Osaka Bay, Japan, had total NPAHs concentrations that ranged from 2380 to 24,688 pg/g dry and 2672 to 25,961 pg/g dry, respectively. Relatively higher concentrations were detected in sampling sites located near the central district and suburbs of Osaka City implying that the most probable sources of NPAHs in the two bivalves are exhaust gases and smokes emitted by automobiles and industrial plants. Bivalves had relatively higher residues of 1-nitronaphthalene, 2-nitronaphthalene, 3-nitrophenanthrene, and 9-nitrophenanthrenes. Residues of 2-nitrofluorene, 1-nitropyrene, 4-nitropyrenes, and 6-nitrochrysene were much lower compared to nitronaphthalenes and nitrophenanthrenes. Inter-species differences was only observed for 2-nitronaphthalene with oysters exhibiting significantly higher residues than mussels. 相似文献
10.
The uranium content and activity ratio A234U/A238U were determined in open ocean water, marine plankton, marine algae and sea water in the environment in which plankton and
algae live. The average uranium content of 3.34±0.28×10−6 g/l and the average activity ratio of 1.13±0.04 were obtained in open ocean water. The uranium contents in plankton and algae
were respectively from 1.7 to 7.8×10−7 g/g and 0.4 to 23.5×10−7 g/g on dry basis with the respective concentration factors of 48 to 260 and 10 to 733. The activity ratio in plankton and
algae ranged from 1.07 to 1.18 which coincided well with those in the environmental sea water. 相似文献