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排序方式: 共有134条查询结果,搜索用时 46 毫秒
41.
Kenichi HOSHINO Yuki YAMAMOTO Xiangping GU Su Young LEE Makoto WATANABE 《Resource Geology》2000,50(3):185-190
Abstract: Possible ore deposition by fluid mixing was preliminarily examined using MIX 99, a FORTRAN program developed for simulating water-rock interactions. We consider mixing of two fluids, the low fO2 and high temperature source fluid and the high fO2 and low temperature seawater. Oxygen fugacity of a mixed fluid formed by titration of seawater into the source fluid gradually decreases with decreasing temperature (model A). Sequential precipitation of ore-forming minerals was examined in this model. On the other hand, simultaneous precipitation of the minerals could be followed by simulation of instantaneous overall mixing of the two fluids (model B). Results of simulation of the both models revealed that a temporal sequence of mineralization observed in the Karuizawa mine, NE Japan, can be formed by model A, while model B is suitable for the mineralization of an active chimney found in the Rainbow hydrothermal area of the Mid-Atlantic Ridge. 相似文献
42.
43.
Masahiro Sugiyama Osamu Akashi Kenichi Wada Amit Kanudia Jun Li John Weyant 《Climatic change》2014,123(3-4):397-411
Energy efficiency is one of the main options for mitigating climate change. An accurate representation of various mechanisms of energy efficiency is vital for the assessment of its realistic potential. Results of a questionnaire show that the EMF27 models collectively represent known channels of energy efficiency reasonably well, addressing issues of energy efficiency barriers and rebound effects. The majority of models, including general equilibrium models, have an explicit end-use representation for the transportation sector. All participating partial equilibrium models have some capability of reflecting the actual market behavior of consumers and firms. The EMF27 results show that energy intensity declines faster under climate policy than under a baseline scenario. With a climate policy roughly consistent with a global warming of two degrees, the median annual improvement rate of energy intensity for 2010–2030 reaches 2.3 % per year [with a full model range of 1.3–2.9 %/yr], much faster than the historical rate of 1.3 % per year. The improvement rate increases further if technology is constrained. The results suggest that the target of the United Nations’ “Sustainable Energy for All” initiative is consistent with the 2-degree climate change target, as long as there are no technology constraints. The rate of energy intensity decline varies significantly across models, with larger variations at the regional and sectoral levels. Decomposition of the transportation sector down to a service level for a subset of models reveals that to achieve energy efficiency, a general equilibrium model tends to reduce service demands while partial equilibrium models favor technical substitution. 相似文献
44.
Toshihiko Masui Kenichi Matsumoto Yasuaki Hijioka Tsuguki Kinoshita Toru Nozawa Sawako Ishiwatari Etsushi Kato P. R. Shukla Yoshiki Yamagata Mikiko Kainuma 《Climatic change》2011,109(1-2):59-76
Representative Concentration Pathway 6.0 (RCP6) is a pathway that describes trends in long-term, global emissions of greenhouse gases (GHGs), short-lived species, and land-use/land-cover change leading to a stabilisation of radiative forcing at 6.0 Watts per square meter (Wm?2) in the year 2100 without exceeding that value in prior years. Simulated with the Asia-Pacific Integrated Model (AIM), GHG emissions of RCP6 peak around 2060 and then decline through the rest of the century. The energy intensity improvement rates changes from 0.9% per year to 1.5% per year around 2060. Emissions are assumed to be reduced cost-effectively in any period through a global market for emissions permits. The exchange of CO2 between the atmosphere and terrestrial ecosystem through photosynthesis and respiration are estimated with the ecosystem model. The regional emissions, except CO2 and N2O, are downscaled to facilitate transfer to climate models. 相似文献
45.
Assessment of nitrogen loading from the Kiso-Sansen Rivers into Ise Bay using stable isotopes 总被引:1,自引:0,他引:1
Ryo Sugimoto Akihide Kasai Kouichi Fujita Kenichi Sakaguchi Tomomi Mizuno 《Journal of Oceanography》2011,67(2):231-240
Concentrations of particulate organic nitrogen (PN), dissolved inorganic nitrogen (DIN), and their nitrogen isotope ratios
(δ
15N) in the Kiso-Sansen Rivers were determined from monthly observations over the course of a year to assess variations in the
form and sources of riverine nitrogen discharged into Ise Bay. The δ
15N values of NO3
− observed in the Kiso-Sansen Rivers showed a logarithmic decreasing trend from 8 to 0‰, which varied with the river discharge,
indicating mixing between point sources with high δ
15N and non-point sources with low δ
15N. The influence of isotope fractionation of in situ biogeochemical processes (mainly DIN assimilation by phytoplankton) on
δ
15N of NO3
− was negligible, because sufficient concentrations of NH4
+ for phytoplankton demand would inhibit the assimilation of NO3
−. A simple relationship between river discharge and δ
15N of NO3
− showed that the fraction of total NO3
− flux arising from point sources increased from 4.0–6.3% (1.1–1.8 tN day−1) during higher discharge (>600 m3 s−1) to 30.2–48.3% (2.6–4.1 tN day−1) during lower discharge (<300 m3 s−1). Riverine NO3
− discharge from the Kiso-Sansen Rivers can explain 75% of the variations in surface NO3
− at the head of Ise Bay over the year. 相似文献
46.
Masahiko Tanaka Tomoki Nakamura Takaaki Noguchi Aiko Nakato Hatsumi Ishida Toru Yada Kei Shirai Akio Fujimura Yukihiro Ishibashi Masanao Abe Tatsuaki Okada Munetaka Ueno Toshifumi Mukai 《Meteoritics & planetary science》2014,49(2):237-244
The crystallization temperatures of Itokawa surface particles recovered by the space probe Hayabusa were estimated by a plagioclase geothermometer using sodic plagioclase triclinicity. The Δ131‐index required for the thermometer, which is the difference in X‐ray diffraction peak positions between the 131 and 11 reflections of plagioclase, was obtained by a high‐resolution synchrotron Gandolfi camera developed for the third generation synchrotron radiation beamline, BL15XU at SPring‐8. Crystallization temperatures were successfully determined from the Δ131‐indices for four particles. The observed plagioclase crystallization temperatures were in a range from 655 to 660 °C. The temperatures indicate crystallization temperatures of plagioclases in the process of prograde metamorphism before the peak metamorphic stage. 相似文献
47.
Konstantin D. Litasov Eiji Ohtani Akio Suzuki Kenichi Funakoshi 《Physics and Chemistry of Minerals》2007,34(3):159-167
High-pressure in situ X-ray diffraction experiment of Fe- and Al-bearing phase D (Mg0.89Fe0.14Al0.25Si1.56H2.93O6) has been carried out to 30.5 GPa at room temperature using multianvil apparatus. Fitting a third-order Birch–Murnaghan equation of state to the P–V data yields values of V 0 = 86.10 ± 0.05 Å3; K 0 = 136.5 ± 3.3 GPa and K′ = 6.32 ± 0.30. If K′ is fixed at 4.0 K 0 = 157.0 ± 0.7 GPa, which is 6% smaller than Fe–Al free phase D reported previously. Analysis of axial compressibilities reveals that the c-axis is almost twice as compressible (K c = 93.6 ± 1.1 GPa) as the a-axis (K a = 173.8 ± 2.2 GPa). Above 25 GPa the c/a ratio becomes pressure independent. No compressibility anomalies related to the structural transitions of H-atoms were observed in the pressure range to 30 GPa. The density reduction of hydrated subducting slab would be significant if the modal amount of phase D exceeds 10%. 相似文献
48.
49.
A Lagrangian ensemble model describing the population dynamics of Neocalanus cristatus was developed. To describe the ecology of N. cristatus, life stage must be included in the model. For this purpose, a new zooplankton compartment, divided into nine life stages, was added to the North Pacific ecosystem model for understanding regional oceanography. In addition, we introduced Lagrangian particles for the copepod population. Each Lagrangian particle represented a population of the same cohort of copepods with information on representative age, developmental stage, growth rate, structural weight, and food satiation. The new model revealed that surviving cohorts are only matched with the phytoplankton bloom after the nauplii stages. The model showed that the existing phytoplankton concentration when copepodites of N. cristatus appear in the surface water determines the development pattern of copepodite stages. The timing of the seasonal phytoplankton bloom depends on climate change, and a sensitivity analysis showed that the multiple spawning strategy through time has an important role in matching the unstable seasonal bloom cycle on a daily basis. The model including the cohorts can collaborate closely with weekly or monthly observations to reveal the rapid response of the marine ecosystem. 相似文献
50.
Yuki Shibazaki Eiji Ohtani Hiroshi Fukui Takeshi Sakai Seiji Kamada Daisuke Ishikawa Satoshi Tsutsui Alfred Q.R. Baron Naoya Nishitani Naohisa Hirao Kenichi Takemura 《Earth and Planetary Science Letters》2012
We have determined the density evolution of the sound velocity of dhcp-FeHx (x ≈ 1) up to 70 GPa at room temperature, by inelastic X-ray scattering and by X-ray diffraction. We find that the variation of VP with density is different for the ferromagnetic and nonmagnetic dhcp-FeHx, and that only nonmagnetic dhcp-FeHx follows Birch's law. Combining our results with Birch's law for iron and assuming an ideal two-component mixing model, we obtain an upper bound of the hydrogen content in the Earth's inner core, 0.23(6) wt.% H, corresponding to FeH0.13(3). The iron alloy with 0.23(6) wt.% H can satisfy the density, and compressional and shear sound velocities of the PREM inner core, assuming that there are no other light elements in the inner core. 相似文献