Concentration of polychlorinated biphenyls (PCBs) in beached resin pellets: variability among individual particles and regional differences   总被引：1，自引：0，他引：1  

Endo S  Takizawa R  Okuda K  Takada H  Chiba K  Kanehiro H  Ogi H  Yamashita R  Date T 《Marine pollution bulletin》2005,50(10):1103-1114

Concentrations of polychlorinated biphenyls (PCBs) in beached resin pellets were examined to reveal variability between individual particles and differences among beaches. Fifty-five resin pellets from a beach in Tokyo were individually analyzed for PCBs, and showed concentrations ranging from <28 to 2,300 ng/g. This indicates that concentrations are highly variable between particles. Among several characters, discoloration (e.g., yellowing) had a positive relationship with PCB concentration: discolored pellets contained more PCBs than others on most of the beaches sampled. Given the color-selective ingestion of food by some organisms, this may be ecotoxicologically important. Measurements of samples from 47 beaches in Japan showed regional differences in PCB concentrations in resin pellets consistent with those in mussels. Sporadic high concentrations of PCBs were also found in pellets from remote islands, suggesting that resin pellets could be the dominant route of exposure to the contaminants at remote sites. The similarity of PCB concentrations between resin pellets and mussels suggests a potential use of resin pellets to monitor pollution in seawater.  相似文献   

The chemical Th-U-total Pb isochron ages of Jiaodong and Jiaonan metamorphic rocks in the Shandong Peninsula, eastern China   总被引：3，自引：0，他引：3  

Masaki  Enami  Kazuhiro  Suzuki  Mingguo  Zhai Xiangshen  Zheng 《Island Arc》1993,2(2):104-113

Abstract The chemical Th-U-total Pb isochron method (CHIME) was applied to determine the age of monazite and thorite in five gneisses and zircon in an ultra high-pressure (UHP) phengite schist from the Su-Lu region, eastern China. The CHIME ages and isotopic ages reported in the literature show that gneisses in the Su-Lu region are divided into middle Proterozoic (1500–1720 Ma) and Mesozoic (100–250 Ma) groups. The Proterozoic group includes paragneiss and orthogneiss of the amphibolite-granulite facies, and their protolith age is late Archean-early Proterozoic. The Mesozoic group is mainly composed of orthogneiss of the greenschist-epidote amphibolite facies, and the protolith age is Middle Paleozoic-Early Proterozoic. The Proterozoic and Mesozoic gneisses occupy northern and southern areas of the Su-Lu region, respectively, which are divided by a major Wulian-Qingdao-Yantai fault. Ultra high-pressure metamorphic rocks occur as blocks in the Mesozoic gneisses, and form a UHP complex.
The UHP phengite schist in the Mesozoic orthogneiss contains detrital zircons with late Proterozoic CHIME age ( ca 860 Ma). Age of the UHP metamorphism is late Proterozoic or younger, and protolith age of the UHP metamorphic rocks is probably different from that of the surrounding Mesozoic gneisses.  相似文献   

Underground storage of carbon dioxide in depleted natural gas reservoirs and in useless aquifers     

Hitoshi Koide  Yoshiyuki Tazaki  Yoshikazu Noguchi  Masaki Iijima  Kazuitsu Ito  Yuji Shindo 《Engineering Geology》1993,34(3-4):175-179

Depleted reservoirs of natural gas and petroleum can provide excellent traps for carbon dioxide. Deep aquifers, which are not used due to high salinity, can host larger amount of the carbon dioxide under their high formation pressure than natural gas and oir reservoirs. Small fraction of aquifers in sedimentary basins in the world are enough to host about 87 gigaton-C of carbon dioxide.

A preliminary technical and economical survey on the carbon dioxide injection system suggests that the energy requirement for carbon dioxide injection into subterranean aquifers is about 269 kWh/ton-C and that the investment and operation costs for system are 79 $/ton-C. By our preliminary cost estimation in Japan, the CO₂-emission-free electricity generation may become possible with a cost increase of 35% for natural-gas-fired power station, and of 60% for coal-fired-power station.  相似文献   

High pressure transitions in the system KAlSi3O8-NaAlSi3O8     

Atsushi Yagi  Toshihiro Suzuki  Masaki Akaogi 《Physics and Chemistry of Minerals》1994,21(1-2):12-17

Phase relations in the system KAlSi₃O₈-NaAlSi ₃O₈ have been examined at pressures of 5–23 GPa and temperatures of 700–1200° C. KAlSi₃O₈ sanidine first dissociates into a mixture of wadeite-type K₂Si₄O₉, kyanite and coesite at 6–7 GPa, which further recombines into KAlSi₃O₈ hollandite at 9–10 GPa. In contrast, NaAlSi₃O₈ hollandite is not stable at 800–1200° C near 23 GPa, where the mixture of jadeite plus stishovite directly changes into the assemblage of calcium ferrite-type NaAlSiO₄ plus stishovite. Phase relations in the system KAlSi₃O₈-NaAlSi₃O₈ at 1000° C show that NaAlSi₃O₈ component gradually dissolves into hollandite with increasing pressure. The maximum solubility of NaAlSi₃O₈ in hollandite at 1000° C was about 40 mol% at 22.5 GPa, above which it decreases with pressure. Unit cell volume of the hollandite solid solution decreases with increasing NaAlSi₃O₈ component. The hollandite solid solution in this system may be an important candidate as a host mineral of K and Na in the uppermost lower mantle  相似文献   

Titanochondrodite and titanoclinohumite derived from the upper mantle in the Buell Park Kimberlite,Arizona, USA   总被引：2，自引：0，他引：2  

Ken-ichiro Aoki  Kiyoshi Fujino  Masaki Akaogi 《Contributions to Mineralogy and Petrology》1976,56(3):243-253

Kimberlite from Buell Park, Arizona, which was intruded into Permian sediments about 30 m.y. ago, is characterized by the hydrous silicates titanochondrodite and titanoclinohumite. Titanochondrodite is the first finding in kimberlites. Optical properties, chemical compositions and cell dimensions of these two minerals are determined.Titanochondrodite and titanoclinohumite are considered to crystallize from kimberlite magma at a depth of about 100 km and at 1,000° C, on the basis of kimberlite mineralogy, petrography and high pressure experimental work. Although there is no direct evidence, the importance of these two minerals in peridotite wedges above sinking lithosphere at the continental margins is also discussed.  相似文献   

Climatic speciation in Japanese ground crickets     

Sinzo Masaki 《GeoJournal》1983,7(6):483-490

The two species groups of ground cricket previously known as P. taprobanensis and P. fascipes are widely distributed from the tropical to temperate regions of East Asia. In the Japanese Islands they show parallel variations along a latitudinal gradient in both developmental and morphometric traits. The ovipositor length varies continuously from 44 to 28°N, but this cline is disrupted by an abrupt shortening farther south. The disruption is associated with changes in the life cycle from the presence to virtual absence of egg diapause and from a short-day to long-day type of nymphal photoperiodic response. It is inferred that the two different types of life cycle were selected for in the temperate and subtropical climates, respectively, and that this differential selection resulted in speciation. Since climatic adaptation seems to be the primary factor involved, this sort of divergence may be called “climatic speciation”.  相似文献   

Infrared spectra of high-pressure hydrous silicates in the system MgO-SiO2-H2O     

Masaki Akaogi  Syun-iti Akimoto 《Physics and Chemistry of Minerals》1986,13(3):161-164

Infrared absorption spectra are presented for four hydrous magnesian silicates which are stable at high pressures and high temperatures characteristic of the earth's mantle: phase A (Mg₇Si₂O₁₄H₆), phase B (approx. Mg₂₃Si₈O₄₂H₆), chondrodite (Mg₅Si₂O₁₀H₂), clinohumite (Mg₉Si₄O₁₈H₂). The results show that phase B as well as phase A, chondrodite and clinohumite contain hydroxyl groups in their structures. It is also suggested that phase B, in addition to phase A, could be of potential importance in the upper mantle and transition zone as a dense host mineral for hydroxyl ions. Chemical composition of phase A was reexamined by microprobe analysis: it agrees well with Mg₇Si₂O₁₄H₆, estimated by Yamamoto and Akimoto (1974, 1977), but disagrees with a newly proposed formula Mg₂SiO₅H₂ by Benimoff and Sclar (1984).  相似文献   

The farming of fish: Hickling, C.F. (1971): 88 pp. 5 figs., 8 tables. Oxford: Pergamon Press Ltd. £ 1.02 (hard cover), 65 p.(flexi)     

Masaki Yamaoka 《Geoforum》1973,4(4):106-107

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Improving Representation of Tropical Cloud Overlap in GCMs Based on Cloud-Resolving Model Data     

Xianwen Jing  Hua Zhang  Masaki Satoh  Shuyun Zhao 《Acta Meteorologica Sinica》2018,32(2):233-245

The decorrelation length (L_cf) has been widely used to describe the behavior of vertical overlap of clouds in general circulation models (GCMs); however, it has been a challenge to associate L_cf with the large-scale meteorological conditions during cloud evolution. This study explored the relationship between L_cf and the strength of atmospheric convection in the tropics based on output from a global cloud-resolving model. L_cf tends to increase with vertical velocity in the mid-troposphere (w₅₀₀) at locations of ascent, but shows little or no dependency on w₅₀₀ at locations of descent. A representation of L_cf as a function of vertical velocity is obtained, with a linear regression in ascending regions and a constant value in descending regions. This simple and dynamic-related representation of L_cf leads to a significant improvement in simulation of both cloud cover and radiation fields compared with traditional overlap treatments. This work presents a physically justifiable approach to depicting cloud overlap in the tropics in GCMs.  相似文献   

Effects of light intensity on the production of VSLs from the marine diatom Ditylum brightwellii     

Abe  Minami  Okuda  Yuki  Hashimoto  Shinya 《Journal of Atmospheric Chemistry》2022,79(1):1-16

Journal of Atmospheric Chemistry - Very short-lived substances (VSLs) are known to play an important role in ozone depletion in the troposphere and stratosphere. Environmental factors that...  相似文献