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11.
In an attempt to detect streaming potentials induced by subsurface water flows, we have observed the horizontal electric field (self-potential) variations across stationary electric dipoles near geothermal wells in the Takinoue geothermal area, Japan. We observed variations of self-potential which seem to be associated with the water flows in the aquifer, induced by turning on and off the flow of the wells. Amplitudes of the variations are 3–5 mV across 60–200 m dipoles, and can be explained well with a proposed electrokinetic model: the streaming potential coefficient of − 15 mV/bar and/or the ζ-potential of −50 to −100 mV in the aquifer are appropriate to explain the observed data by the model. The obtained electrokinetic coupling coefficients are in situ ones and determined for crustal rock-water system under high temperature (˜200°C) condition. The present results, together with a laboratory study by Ishido and Mizutani (1981), give fundamental information on electrokinetic coupling coefficients in the earth's interior, and are very important when we make quantitative interpretations of self-potentials generated by geothermal activity on the basis of electrokinetic effects. 相似文献
12.
A. Kouchi S. Hosoya M. Kitamura H. Takei I. Sunagawa 《Physics and Chemistry of Minerals》1983,9(3-4):167-172
The effective distribution coefficient K eff of Ni between solid and liquid has been experimentally determined as a function of growth rates and crystallographic orientations for (Mg, Ni)2SiO4 crystals grown by the floating-zone method. Crystals were grown by the continuous mechanism at slow rates, but were faceted at high rates, which enables us to determine the dependence of K eff on orientations and on smooth versus rough interfaces. It has been verified that K eff of Ni becomes larger than the equilibrium value K o as the growth rate increases and that K eff of faceted «110» directions is larger than that of non-faceted higher index directions. The results can be qualitatively explained by the theories which treat the distribution of elements in relation to growth kinetics. Element distribution during the recovery process from rounded to faceted morphology is also analysed in detail. 相似文献
13.
S. Yukimoto M. Endoh Y. Kitamura A. Kitoh T. Motoi A. Noda T. Tokioka 《Climate Dynamics》1996,12(10):667-683
Interannual and interdecadal variabilities in the Pacific are investigated with a coupled atmosphere-ocean GCM developed
at MRI, Japan. The model is run for 70 years with flux adjustments. The model shows interannual variability in the tropical
Pacific which has several typical characteristics shared with the observed ENSO. A basin-scale feature of the principal SST
variation for the ENSO time scale shows negative correlation in the central North Pacific with the tropical SST, similar to
that of the observed one. Associated variation of the model atmosphere indicates an intensification of the Aleutian Low and
a PNA-like teleconnection pattern as a response to the tropical warm SST anomaly. The ENSO time scale variability in the midlatitude
ocean consists of the westward propagation of the subsurface temperature signal and the temperature variation within the shallow
mixed layer forced by the anomalous atmospheric heat fluxes. For the interdecadal time scale, variation of the SST is simulated
realistically with a geographical pattern similar to that for the ENSO time scale, but it has a larger relative amplitude
in the northern Pacific. For the atmosphere, spatial structure of the variation in the interdecadal time scale is also similar
to that in the ENSO time scale, but has smaller amplitude in the northern Pacific. Long oceanic spin-up time (>∼10 y) in the
mid-high latitude, however, makes oceanic response in the interdecadal time scale larger than that in the ENSO time scale.
The lagged-regression analysis for the ocean temperature variation relative to the wind stress variation indicates that interdecadal
variation of the ocean subsurface at the mid-high latitudes is considered as enhanced ocean gyre spin-up process in response
to the atmospheric circulation change at the mid-high latitudes, remotely forced by the interdecadal variation of the tropical
SST.
Received: 6 November 1995 / Accepted: 19 April 1996 相似文献
14.
Kosmochlor (NaCrSi2O6) was synthesized by the flux method from melts along the join Na2O·2 SiO2-Na2O·Cr2O3·4 SiO2 at 1000° C in air, and isolated by dissolving the glassy matrix with hydrofluoric and perchloric acids. The join CaMgSi2O6-NaCrSi2O6 was studied at 1 atmosphere in air by the quenching technique at temperatures between 900° and 1450° C, using mixtures of kosmochlor and diopside crystals or diopside glass as starting materials. The phases are diopside solid solution, kosmochlor, spinel (Mg-chromite), eskolaite (Cr2O3) and glass. The maximum solubility of kosmochlor in diopside is 24 wt percent at 1140° C, while diopside is not soluble at all in kosmochlor, resulting in the existence of a wide range of immiscibility. Petrologic significance of the results is discussed. 相似文献
15.
An experiment on evapotranspiration from citrus trees under irrigation with saline water was carried out for 4 months. Two lysimeters planted with a citrus tree in the green house were used. One lysimeter was irrigated with saline water (NaCl and CaCl2 of 2000 mg/L equivalence,EC = 3.8 dS/m, SAR = 5.9) and the other was irrigated with freshwater using drip irrigation. The applied irrigation water was 1.2 times that of the evapotranspiration on the previous day. Evapotranspiration was calculated as the change in lysimeter weight recorded every 30 minutes. The lysimeters were filled with soil with 95.8% sand. The results of the experiment were as follows. (i) The evapotranspiration from citrus tree was reduced after irrigation with saline water. The evapotranspiration returns to normal after leaching. However it takes months to exhaust the salt from the tree. (ii) To estimate the impact of irrigation with saline water on the evapotranspiration from citrus trees, the reduction coefficient due to salt stress (Ks) was used in this experiment. Evapotranspiration under irrigation with saline water (ET s ) can be calculated from evapotranspiration under irrigation with freshwater (ET) by the equationET s =K s × ET. Ks can be expressed as a function ofEC sw . (iii) The critical soil-water electrical conductivity (EC sw ) is 9.5 dS/m, beyond which adverse effects on evapotranspiration begin to appear. IfEC sw can be controlled at below 9.5 dS/m, saline water can be safely used for irrigation. 相似文献
16.
The system CaMgSi2O6CaAl2SiO6CaFeAlSiO6 has been studied in air at 1 atm. The phase assemblage at subsolidus temperatures in the CaMgSi2O6-rich portion is Cpx + An + Mel and that in the CaMgSi2O6-poor portion Cpx + An + Mel + Sp. At subsolidus temperatures the sigle-phase field of clinopyroxene increases with an increase in the CaFeAlSiO6 component of the system. The Al2O3 content of clinopyroxene, however, continues to increase beyond the single-phase field and attains at least 16.04 wt.% Al2O3 with 3.9 wt.% Fe2O3. The stability field of fassaite in the system over a range of pressures and oxygen fugacities has been estimated from data in the literature as well as the present data. The CaFeAlSiO6 content of fassaite is dependent on oxygen fugacity, but is not influenced by pressure. The stability field is strongly influenced by oxygen fugacity at low and high pressure, and decreases with decreasing oxygen fugacity. Clinopyroxenes in both volcanic and metamorphic rocks from various localities, when plotted on the CaMgSi2O6CaAl2SiO6CaFeAlSiO6 triangle, show that there is no compositional gap between diopside and fassaitic pyroxene in metamorphic rocks, and that the fassaitic pyroxene in alkalic rocks becomes richer in both CaAl2SiO6 and CaFeAlSiO5 components as crystallization proceeds. These results agree with those obtained in the experimental study. 相似文献
17.
The behaviour of tetrahedrally coordinated and octahedrally coordinated Cr3+ ions in diopside is discussed from the study on the join CaMg-Si2O6-CaCrCrSiO6. The molecule CaCrCrSiO6 decomposes into uvarovite+eskolaite and its maximum solubility in diopside is 6.7 wt percent at 940 ° C. Crystalline phases are diopside ss (ss is abbreviation of solid solution), uvarovite ss, wollastonite ss, spinel and eskolaite. The diopside ss is blue in colour. Its optical spectra were measured in the wavelenght range of 325–2600 nm, and assigned after tetrahedral configuration Td and octahedral configuration Oh. It is estimated that octahedral Cr3+ ions are in high spin state, while tetrahedral Cr3+ ions may be probably in low spin state. The t and B are 10,300–10,370 cm–1 and 429–432 cm–1. The CFSE for tetrahedral low spin Cr3+ ions is nearly the same as that for octahedral high spin Cr3+ ions. The ionic radii of tetrahedral low spin Cr3+ ions calculated are 0.47–0.53 Å, shrinked from the radius of octahedral high spin Cr3+ ion (0.615 Å) as much as 14–24 percent. Petrologic implications of the result are also discussed.The first half of the D. Sc. dissertation of K. Ikeda presented to Hokkaido University in June, 1976 相似文献
18.
E. Curti K. Fujiwara J. Tits A. Kitamura W. Müller 《Geochimica et cosmochimica acta》2010,74(12):3553-5422
High-purity synthetic barite powder was added to pure water or aqueous solutions of soluble salts (BaCl2, Na2SO4, NaCl and NaHCO3) at 23 ± 2 °C and atmospheric pressure. After a short pre-equilibration time (4 h) the suspensions were spiked either with 133Ba or 226Ra and reacted under constant agitation during 120-406 days. The pH values ranged from 4 to 8 and solid to liquid (S/L) ratios varied from 0.01 to 5 g/l. The uptake of the radiotracers by barite was monitored through repeated sampling of the aqueous solutions and radiometric analysis. For both 133Ba and 226Ra, our data consistently showed a continuous, slow decrease of radioactivity in the aqueous phase.Mass balance calculations indicated that the removal of 133Ba activity from aqueous solution cannot be explained by surface adsorption only, as it largely exceeded the 100% monolayer coverage limit. This result was a strong argument in favor of recrystallization (driven by a dissolution-precipitation mechanism) as the main uptake mechanism. Because complete isotopic equilibration between aqueous solution and barite was approached or even reached in some experiments, we concluded that during the reaction all or substantial fractions of the initial solid had been replaced by newly formed barite.The 133Ba data could be successfully fitted assuming constant recrystallization rates and homogeneous distribution of the tracer into the newly formed barite. An alternative model based on partial equilibrium of 133Ba with the mineral surface (without internal isotopic equilibration of the solid) could not reproduce the measured activity data, unless multistage recrystallization kinetics was assumed. Calculated recrystallization rates in the salt solutions ranged from 2.8 × 10−11 to 1.9 × 10−10 mol m−2 s−1 (2.4-16 μmol m−2 d−1), with no specific trend related to solution composition. For the suspensions prepared in pure water, significantly higher rates (∼5.7 × 10−10 mol m−2 s−1 or ∼49 μmol m−2 d−1) were determined.Radium uptake by barite was determined by monitoring the decrease of 226Ra activity in the aqueous solution with alpha spectrometry, after filtration of the suspensions and sintering. The evaluation of the Ra uptake experiments, in conjunction with the recrystallization data, consistently indicated formation of non-ideal solid solutions, with moderately high Margules parameters (WAB = 3720-6200 J/mol, a0 = 1.5-2.5). These parameters are significantly larger than an estimated value from the literature (WAB = 1240 J/mol, a0 = 0.5).In conclusion, our results confirm that radium forms solid solutions with barite at fast kinetic rates and in complete thermodynamic equilibrium with the aqueous solutions. Moreover, this study provides quantitative thermodynamic data that can be used for the calculation of radium concentration limits in environmentally relevant systems, such as radioactive waste repositories and uranium mill tailings. 相似文献
19.
20.
Masatoshi Kitamura 《Astrophysics and Space Science》2005,296(1-4):33-41
It was in 1936 when a young Czech student of age 22 came to Japan through Siberia for participating in the solar eclipse expedition.
Since then, he had visited us 13 times until 1993 (when he passed away). At each visit his lectures were vivid for us and
had strong impact on the audience. Needless to say, it was the late Professor Zdeněk Kopal. In this brief presentation first
I reveal my reminiscences of our common time in Manchester and Japan as a contemporary, and second I make some remarks on
my activities for the Japanese Official Development Assistance (ODA) for astronomy in developing countries, in a similar way
like Professor Kopal contributed in later years to the development of astronomy mainly in middle-east countries. 相似文献