Effects of ligand speciation on determinations of the complexing abilities of strong ligands in natural waters     

Takashi Midorikawa  Eiichiro Tanoue 《Journal of Oceanography》1996,52(4):421-439

The presence of organic ligands (L) whose conditional stability constants (K_ML) are strong enough to allow them to form complexes with copper has been reported in oceanic waters. However, there is no general agreement on the distributional characteristics of such strong ligands in the water column. We present that these inconsistencies are derived from not only different analytical methods employed for their detection but also different oceanographic conditions. In particular, the nature and quantities of detectable natural ligands are affected by what kind of form the ligands are presentin situ in different marine environments, that is, chemical speciation of natural ligands (ligand speciation), which depends strongly on the variations in concentrations of coexisting trace metals. Using published data from observations in the laboratory and the field, we provide limits to the ranges of conditional stability constants of organic ligands for copper, zinc and cadmium that are detectable by the extensively used direct metal-titration method. For example, our model indicates that organic ligands for copper with log K_CuL(Cu)>12.4 in surface water and with log K_CuL(Cu)>9.9 in deep water might not have been detected because stronger ligands had formed complexes with ambient metalsin situ at a station in the North Pacific. The estimation suggests that there is a basinscale difference in speciation of natural organic ligands and, moreover, that this difference influences metal speciation. It is postulated that comparisons of the occurrence and levels of organic ligands might not be possible among spatially and temporally different observations without reconciliation of the effects of speciation of the ligands, even if an identical method is used in every case.  相似文献   

Determination of the lithium and rubidium in sea water by double channel flame emission spectrophotometry     

Taitiro Fujinaga  Tooru Kuwamoto  Eiichiro Nakayama  Shinji Tanaka 《Journal of Oceanography》1980,36(4):196-200

A precise and accurate technique for the determination of Li and Rb in sea water has been developed by using a double channel flame emission spectrophotometer. The advantage of this technique is that it is possible to correct the background emission by making use of the double channel system of the apparatus and to obtain constant intensity of emission even if there are large scale changes in the salinity of the sample. Sea water samples collected in the open sea and coastal areas of Japan were analyzed by this method. In one of the coastal areas, an extraordinarily high concentration of Li was found.  相似文献   

Direct determination of barium in Sea water by inductively coupled plasma emission spectrometry     

Masahito Sugiyama  Masakazu Matsui  Eiichiro Nakayama 《Journal of Oceanography》1984,40(4):295-302

A method for the determination of barium in sea water was investigated using inductively coupled plasma emission spectrometry, and sea water samples from the Japan Sea and the Pacific Ocean were directly analyzed by this method. Artificial sea water was used to prepare matrix matched standard solutions to overcome the problem of physical interference. The detection limit (signal/noise ratio=2) for barium in deionized and distilled water was 0.08µg l^?1 and in sea water, 0.12µg l^?1. The reproducibilities in the purified water and in the sea water at the 10µg l^?1 level were 0.7% a#FFFFFFnd 0.5%, respectively. The barium concentration in both the Japan Sea and the Pacific Ocean increased with depth and ranged between 5.5–10.0µg l^?1 and 4.1–18.4µg l^?1, respectively.  相似文献   

Groundwater resources management under environmental constraints in Shiroishi of Saga plain,Japan     

Nguyen Cao Don  Nguyen Thi Minh Hang  Hiroyuki Araki  Hiroyuki Yamanishi  Kenichi Koga 《Environmental Geology》2006,49(8):1223-1223

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午后多重极光弧观测研究          下载免费PDF全文

温艳波  杨惠根  韩德胜  T.Araki  艾勇  刘瑞源  刘勇华  胡泽骏  陈卓天  邓忠新  刘嵘  王晶 《极地研究》2005,17(4):255-263

本文利用2001-2003年南极中山站175天全天空摄像机观测,对午后多重极光弧的出现率及其与Kp指数的关系进行了统计分析,结果表明午后多重极光弧出现率呈一单峰分布,最大发生率出现在1445UT(1645MLT),其位置在1500MLT极光热点(1300-1700MLT)近夜侧的部分。与地磁活动指数Kp的相关统计分析表明,Kp值为2-3之间时多重极光弧有较大的出现率,这说明中等地磁活动情形下午后多重极光弧有较高的出现率。事件分析表明多重极光弧的强度变化与地磁Pc5脉动具有较高的相关性,并且有类似的频谱特征,这说明午后多重极光弧可能与同时出现的Pc5地磁脉动有关。  相似文献   

Lithological and physical properties of core samples from the Sagara oil field: Oil occurrence in Sagara core samples     

Satoshi  Hirano  Yoshiaki  Araki  Koji  Kameo  Hiroshi  Kitazato  Hideki  Wada 《Island Arc》2006,15(3):313-327

Abstract   A drilling and coring investigation of the Sagara oil field, central Honshu, Japan, was conducted to contribute to the understanding of hydrocarbon migration processes in a forearc basin. Core samples were analyzed to determine lithology, physical properties (specifically gas permeability) and the characteristics of oil occurrence. Gas permeability values greater than approximately 10⁻¹¹ m² constitute the basic precondition for any lithology to serve as a potential fluid conduit or reservoir in the Sagara oil field. Cores recovered from the 200.6-m-deep borehole were primarily composed of alternating siltstone, sandstone and conglomerate, all of which are correlated to the late Miocene Sagara Group. Both sandstone and conglomerate can be classified into two types, carbonate-cemented and poorly to non-cemented, based on matrix material characteristics. Oil stains are generally absent in the former lithology and more common in the latter. Variations in physical properties with respect to gas permeability values are directly related to the presence and character of carbonate cement, with higher permeabilities common in poorly to non-cemented rocks. The relationships between lithology, oil-staining, cementation and permeability indicate that cementation preceded oil infiltration and that cementation processes exerted significant control on the evolution of the reservoir.  相似文献   

On a time-symmetric Hermite integrator for planetary N-body simulation   总被引：2，自引：0，他引：2  

Eiichiro Kokubo  Keiko Yoshinaga  & Junichiro Makino 《Monthly notices of the Royal Astronomical Society》1998,297(4):1067-1072

We describe a P(EC) ⁿ Hermite scheme for planetary N -body simulation. The fourth-order implicit Hermite scheme is a time-symmetric integrator that has no secular energy error for the integration of periodic orbits with time-symmetric time-steps. In general N -body problems, however, this advantage is of little practical significance, since it is difficult to achieve time-symmetry with individual variable time-steps. However, we can easily enjoy the benefit of the time-symmetric Hermite integrator in planetary N -body systems, where all bodies spend most of the time on nearly circular orbits. These orbits are integrated with almost constant time-steps even if we adopt the individual time-step scheme. The P(EC) ⁿ Hermite scheme and almost constant time-steps reduce the integration error greatly. For example, the energy error of the P(EC)² Hermite scheme is two orders of magnitude smaller than that of the standard PEC Hermite scheme in the case of an N  = 100,  m  = 10²⁵ g planetesimal system with the rms eccentricity 〈 e ²〉^1/2 ≲0.03.  相似文献   

Extension of a polar ionospheric current to the nightside equator     

Tohru Araki  Joe H. Allen  Yuriko Araki 《Planetary and Space Science》1985,33(1):11-16

A detailed analysis of rapid-run magnetograms from Guam (geomagnetic latitude = 4.2°) revealed that there are two kinds of geomagnetic sudden commencement (SC) observed in nighttime. One is the ordinary SC consisting of a main impulse only which has a smooth rise of the H-component. The other is a superposition by a small positive impulse on the very beginning part of the smooth rise of the main impulse and consequently the SC starts with a small stepwise increase of the H-component. The latter type of SC occurs between 20 and 08 h L.T. and its occurrence rate takes the maximum value of about 50% around 03 h L.T. Corresponding magnetograms from a dayside equatorial station (Huancayo, geomagnetic latitude = ?0.7°) were examined and a good correlation was found between the stepwise SC at the nightside (Guam) and SC¹ with a preliminary reverse impulse (PRI) at the dayside (Huancayo). Since PRI observed at the dayside equator may be interpreted as an extension of an ionospheric current due to an dusk-to-dawn electric field impressed on the polar ionosphere, our results show that a polar originating ionospheric current can extend to the nightside equator and produce a small but observable magnetic effect in spite of much reduced nighttime ionospheric conductivity.  相似文献   

Similarity of electrophoretic dissolved protein spectra from coastal to pelagic seawaters     

Namiha Yamada  Eiichiro Tanoue 《Journal of Oceanography》2009,65(2):223-233

Dissolved proteins in seawater samples collected from a coastal area of Tokyo Bay, Sagami Bay and a location off the Kuroshio Current were investigated by one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and high resolution two-dimensional electrophoresis (2-DE). Four to nine protein bands were detected in SDS-PAGE in the apparent molecular weight (MW) range from 12 kilo Dalton (kDa) to 49 kDa. The 2-DE technique distinguished 10 to 46 protein spots exhibiting isoelectric point (pI)/MW ranging 4.3–9.2/12–63 kDa. The elecrophoretic patterns were similar between the coastal and pelagic samples, as well as previously reported patterns from various pelagic areas. The close similarity of electrophoretic mobility on both SDS-PAGE and 2-DE gels indicates the compositional homogeneity of dissolved proteins in seawater throughout a broad range of marine environments. Proteinaceous dissolved organic matter (DOM) that was unresolved and smeared staining characteristics on both SDS-PAGE and 2-DE gels was first observed in Tokyo Bay waters in the present study and its possible sources are discussed. Although the two protein species, 48 kDa and 39 kDa proteins, have been identified as homologues of Porin P and low molecular weight-alkaline phosphatase of Pseudomonas aeruginosa PAO1, respectively, four strains of P. aeruginosa and two species of Pseudomonas spp. have been newly identified as the source organisms of these proteins using the N-terminal amino acid sequence data determined in previous studies.  相似文献   

The interplanetary electric field, cleft currents and plasma convection in the polar caps     

P. M. Banks  T. Araki  C. R. Clauer  J. P. ST. Maurice  J. C. Foster 《Planetary and Space Science》1984,32(12):1551-1557

This report investigates the suggestion that the pattern of plasma convection in the polar cleft region is directly determined by the interplanetary electric field (IEF). Owing to the geometrical properties of the magnetosphere, the East-West component of the IEF will drive field-aligned currents which connect to the ionosphere at points lying on either side of noon, while currents associated with the North-South component of the IEF will connect the two polar caps as sheet currents centered at noon. The effects of the hypothesized IEF driven cleft current systems on polar cap ionospheric plasma convection are investigated through a series of numerical simulations. The simulations demonstrate that this simple electrodynamic model can account for the narrow “throats” of strong dayside antisunward convection observed during periods of southward interplanetary magnetic field (IMF) as well as the sunward convection observed during periods of strongly northward IMF. Thedawn-dusk shift of polar cap convection which is related to the B_y component of the IMF is also accounted for by the model.  相似文献