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231.
Shiro ITOH Shigeru TERASHIMA Noboru IMAI Hikari KAMIOKA Naoki MITA Atsushi ANDO 《Geostandards and Geoanalytical Research》1993,17(1):5-79
Abstract: Analytical data for fourteen rare-earth elements, scandium, yttrium, zirconium and hafnium, received by May 1992, have been compiled on twenty-six GSJ (Geological Survey of Japan) reference samples. Seventeen of them are 'Igneous rock series' and nine are "Sedimentary rock series". The reported data including personal communication were evaluated under the consideration on analytical methods and geochemical evidences. No significant difference has been observed between the values obtained by the different analytical methods. Based on the selected available data, 1992 compilation values were tabulated. 相似文献
232.
Shigeru TERASHIMA Atsushi ANDO Takashi OKAI Yutaka KANAI Masahiro TANIGUCHI Fuminori TAKIZAWA Shiro ITOH 《Geostandards and Geoanalytical Research》1990,14(1):1-5
Nine new rock reference samples of the "Sedimentary rock series", Chert JCh-1, Dolomite JDo-1, Lake sediment JLk-1, Limestone JLs-1, Stream sediments JSd-1 to JSd-3, and Slates JS1-1 and JSl-2 have been prepared by the Geological Survey of Japan(GSJ). Thirty major, minor and trace elements were determined using atomic absorption spectrometry, flame emission spectrometry, infrared absorption spectrometry and wet chemical techniques. The results of homogeneity tests showed that almost all elements, with a few exceptions, are considered to be distributed homogeneously in each reference sample. 相似文献
233.
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
234.
Model of nucleation and growth of crystals in cooling magmas 总被引:4,自引:0,他引:4
Atsushi Toramaru 《Contributions to Mineralogy and Petrology》1991,108(1-2):106-117
The nucleation and growth of liquidus phases in cooling magmas at constant rates are modeled taking into account homogeneous
nucleation, diffusion-limited growth, and depletion of crystallizing component from melt, and the temperature-dependent diffusivity.
The formulation of governing equations shows that four dimensionless parameters, whose physical meanings are the nucleation
difficulty, the fusion enthalpy, the ratio of the growth rate to the cooling rate, and the activation energy of diffusion,
control the crystallization phenomena. The nucleation behavior with time (or temperature) is determined primarily by the competition
between increasing nucleation rate with cooling and the reduced supersaturation with depletion by progressive growth of crystals
previously nucleated. The maximum nucleation rate and the number density of crystals increase with decreasing interfacial
tension and diffusivity, and with increasing fusion enthalpy and cooling rate. Quantitative expressions of the time or temperature
interval for which the nucleation remains appreciable, the peak nucleation rate, the number density of crystals and the mean
crystal radius are derived as functions of controlling parameters, and can be used to estimate the cooling rate or other unknown
parameters from the number density of crystals of a rock. 相似文献
235.
Noboru IMAI Shigeru TERASHIMA Shiro ITOH Atsushi ANDO 《Geostandards and Geoanalytical Research》1996,20(2):165-216
Analytical data compiled on nine Geological Survey of Japan (GSJ) reference samples, "Sedimentary rock series" received by February 1996 are reported. After excluding outliers and examining critically the analytical procedures employed, the data were evaluated statistically. Recommended or preferable values for fifteen major and sixty minor and trace elements are proposed. 相似文献
236.
Geoelectric potential difference monitoring has been conducted in Kozu-shima Island about 170 km south of Tokyo. During the monitoring period (14 May 1997–30 November 1999), there were 21 anomalous geoelectric changes that could have been VAN-type seismic electric signals (SES) and 26 M>3 earthquakes within about 20 km. Possible correspondence between the geoelectric changes and earthquakes has been examined. There seems to be some systematic tendency regarding the dependence of appearance/non-appearance of changes and their polarity on epicentral location. This observation, however, is preliminary and admittedly inconclusive because of small number of cases and non-uniqueness in signal-earthquake correlation. 相似文献
237.
Jurassic and Lower Cretaceous radiolarian zonation in Japan and in the western Pacific 总被引:7,自引:0,他引:7
Abstract A radiolarian zonal scheme for the entire Jurassic and Lower Cretaceous using biostratigraphic data from both Japanese Island sections and the western Pacific seafloor is documented. The zonation is applicable to low and middle paleolatitude portions of the Paleo-Pacific ocean. Radiolarian bio-events such as the evolutionary first appearance biohorizon, first occurrence biohorizon, and last occurrence biohorizon were used to define zones. The 11 zones proposed are, in ascending order, Parahsuum simplum, Trillus elkhornensis, Laxtorum(?) jurassicum, Tricolocapsa plicarum, Tricolocapsa conexa, Stylocapsa(?) spiralis, Hsuum maxwelli, Pseudodictyomitra primitiva, Pseudodictyomitra carpatica, Cecrops sep-temporatus, and Acanthocircus carinatus zones. Preliminary age assignments for these zones are presented. 相似文献
238.
Numerical simulation of mitigation for liquefaction-induced soil deformations in a sandy ground improved by cement grouting 总被引:4,自引:0,他引:4
This paper presents a numerical study of mitigation for liquefaction during earthquake loading. Analyses are carried out using
an effective stress based, fully coupled, hybrid, finite element-finite differences approach. The sandy soil behavior is described
by means of a cyclic elastoplastic constitutive model, which was developed within the framework of a nonlinear kinematic hardening
rule. In theory, the philosophies of mitigation for liquefaction can be summarized as two main concepts, i.e. prevention of
excess pore water pressure generation and reduction of liquefaction-induced deformations. This paper is primarily concerned
with the latter approach to liquefaction mitigation. Firstly, the numerical method and the analytical procedure are briefly
outlined. Subsequently, a case-history study, which includes a liquefaction mitigation technique of cement grouting for ground
improvement of a sluice gate, is conducted to illustrate the effectiveness of liquefaction countermeasures. Special emphasis
is given to the computed results of excess pore water pressures, displacements, and accelerations during the seismic excitation.
Generally, the distinctive patterns of seismic response are accurately reproduced by the numerical simulation. The proposed
numerical method is thus considered to capture the fundamental aspects of the problems investigated, and yields results for
design purposes. From the results in the case, excess pore water pressures eventually reach fully liquefied state under the
input earthquake loading and this cannot be prevented. However, liquefaction-induced lateral spreading of the foundation soils
can be effectively reduced by the liquefaction mitigation techniques.
An erratum to this article can be found at 相似文献
239.
Seda Şalap-Ayça Piotr Jankowski Keith C Clarke Phaedon C Kyriakidis Atsushi Nara 《International journal of geographical information science》2018,32(4):637-662
The paper presents a computationally efficient meta-modeling approach to spatially explicit uncertainty and sensitivity analysis in a cellular automata (CA) urban growth and land-use simulation model. The uncertainty and sensitivity of the model parameters are approximated using a meta-modeling method called polynomial chaos expansion (PCE). The parameter uncertainty and sensitivity measures obtained with PCE are compared with traditional Monte Carlo simulation results. The meta-modeling approach was found to reduce the number of model simulations necessary to arrive at stable sensitivity estimates. The quality of the results is comparable to the full-order modeling approach, which is computationally costly. The study shows that the meta-modeling approach can significantly reduce the computational effort of carrying out spatially explicit uncertainty and sensitivity analysis in the application of spatio-temporal models. 相似文献
240.
Masahiro Sugiyama Yosuke Arino Takanobu Kosugi Atsushi Kurosawa Shingo Watanabe 《Climate Policy》2018,18(6):681-689
Climate engineering has received increasing attention, but its discussion has remained on the sidelines of mainstream climate policy. The policy relevance of this previously exotic option is poised to rise because of the gap between the temperature goals of the Paris Agreement and slow global mitigation efforts. It is therefore crucial to understand the risks and benefits of the proposed schemes, and the social implications of policy choices. Assessment of the risks and benefits of solar geoengineering strongly depends on scenarios, but previous scenarios have not reflected the full range of social choices. In light of concerns over risks, a newer set of scenarios is desirable, which represents both uncertainties and social choices more fully. Borrowing and extending lessons from recent literature on the new community climate scenario process, we envision a possible scenario-building process that combines interdisciplinary scholarship with the involvement of stakeholders and citizens. The resultant scenarios would better characterize uncertainties of, and policy choices for, solar geoengineering, and foster critical appraisal of its risks and benefits. Such societal choices might include not only total ban and large-scale deployment, but also limited deployment, which has received less attention in the scenario literature. The interaction between scenario and governance research would be able to highlight the central issues at stake, including ethical, social, and political dimensions.
Key policy insights
A more comprehensive assessment of solar geoengineering is necessary to evaluate its risks and benefits, necessitating new scenario research
It is crucial to reflect the full span of policy choices and uncertainties with interdisciplinary collaboration in such scenarios
Such societal choices might include not only total ban and large-scale deployment, but also limited deployment, which has received less attention in the scenario literature
Participatory scenario research would enable incorporating the concerns and opinions of stakeholders and citizens in scenario creation