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排序方式: 共有273条查询结果,搜索用时 15 毫秒
111.
Masayuki Uesugi Motoo Ito Hikaru Yabuta Hiroshi Naraoka Fumio Kitajima Yoshinori Takano Hajime Mita Yoko Kebukawa Aiko Nakato Yuzuru Karouji 《Meteoritics & planetary science》2019,54(3):638-666
Carbonaceous materials in the sample catcher of the Hayabusa spacecraft were assigned as category 3 particles. We investigated the category 3 particles with a suite of in situ microanalytical methods. Possible contaminants collected from the cleanrooms of the spacecraft assembly and extraterrestrial sample curation center (ESCuC) were also analyzed in the same manner as category 3 particles for comparison. Our data were integrated with those of the preliminary examination team for category 3 particles. Possible origins for the category 3 particles include contamination before and after the operation of the Hayabusa spacecraft. 相似文献
112.
113.
Accurate measurements of cell parameters were performed on the ilmenite phases of ZnSiO3 and MgGeO3 using an X-ray diffraction method under hydrostatic conditions. The linear changes in cell parameter are represented by 1?a/a 0=(1.06±0.04)×10?4 P(kbar) and 1?c/c 0=(2.11±0.04)×10?4 P for ZnSiO3, and 1?a/a 0=(1.37±0.03)×10?4 P and 1?c/c 0=(2.05±0.04)×10?4 P for MgGeO3. A least-squares calculation using the first-order Birch-Murnaghan equation gives K T =2.16±0.02 Mbar and K T =1.87±0.02 Mbar for ZnSiO3 and MgGeO3, respectively. Elastic systematics assuming K T V m =constant give a predicted value K T =2.14 Mbar for the ilmenite phase of MgSiO3. 相似文献
114.
R. Hino D. Inazu Y. Ohta Y. Ito S. Suzuki T. Iinuma Y. Osada M. Kido H. Fujimoto Y. Kaneda 《Marine Geophysical Researches》2014,35(3):181-190
Ocean-bottom pressure records obtained near the epicenter of the 2011 Tohoku-Oki earthquake were examined to test whether the earthquake was preceded by substantial precursory crustal deformation. The seafloor data enabled us to search for small-scale preslip near the epicenter that would be difficult to identify from terrestrial geodetic data. After treating the data to reduce nontectonic fluctuations, we obtained a time series of seafloor vertical deformation in the epicentral region with a noise level of 2–4 cm. No significant crustal deformation related to preslip was detected in the period of roughly a day before the mainshock, whereas postseismic deformation associated with the largest foreshock 2 days before the mainshock was apparent. From our quantitative estimate of the sensitivity of the seafloor network in detecting slip on the plate interface, we conclude that the Tohoku-Oki earthquake was not preceded by preslip with moment release greater than moment magnitude (Mw) 6.2 in the vicinity of the hypocenter or greater than Mw 6.0 along the subduction interface near the trench. 相似文献
115.
Tomoo Katsura Sho Yokoshi Kazuyuki Kawabe Anton Shatskiy Maki Okube Hiroshi Fukui Eiji Ito Akifumi Nozawa Ken-ichi Funakoshi 《Physics and Chemistry of Minerals》2007,34(4):249-255
The electrical conductivity of (Mg0.93Fe0.07)SiO3 ilmenite was measured at temperatures of 500–1,200 K and pressures of 25–35 GPa in a Kawai-type multi-anvil apparatus equipped
with sintered diamond anvils. In order to verify the reliability of this study, the electrical conductivity of (Mg0.93Fe0.07)SiO3 perovskite was also measured at temperatures of 500–1,400 K and pressures of 30–35 GPa. The pressure calibration was carried
out using in situ X-ray diffraction of MgO as pressure marker. The oxidation conditions of the samples were controlled by
the Fe disk. The activation energy at zero pressure and activation volume for ilmenite are 0.82(6) eV and −1.5(2) cm3/mol, respectively. Those for perovskite were 0.5(1) eV and −0.4(4) cm3/mol, respectively, which are in agreement with the experimental results reported previously. It is concluded that ilmenite
conductivity has a large pressure dependence in the investigated P–T range. 相似文献
116.
One answer to the question posed in the title is that we will have more accurate data for arrival times of SH waves, because the rotational component around the vertical axis is sensitive to SH waves although not to P-SV waves. Importantly, there is another answer related to seismic sources, which will be discussed in this paper.
Generally, not only dislocations commonly used in earthquake models but also other kind of defects could contribute to producing seismic waves. In particular, rotational strains at earthquake sources directly generate rotational components in seismic waves. Employing the geometrical theory of defects, we obtain a general expression for the rotational motion of seismic waves as a function of the parameters of source defects.
Using this expression, together with one for translational motion, we can estimate the rotational strain tensor and the spatial variation of slip velocity in the source area of earthquakes. These quantities will be large at the edges of a fault plane due to spatially rapid changes of slip on the fault and/or a formation of tensile fractures. 相似文献
Generally, not only dislocations commonly used in earthquake models but also other kind of defects could contribute to producing seismic waves. In particular, rotational strains at earthquake sources directly generate rotational components in seismic waves. Employing the geometrical theory of defects, we obtain a general expression for the rotational motion of seismic waves as a function of the parameters of source defects.
Using this expression, together with one for translational motion, we can estimate the rotational strain tensor and the spatial variation of slip velocity in the source area of earthquakes. These quantities will be large at the edges of a fault plane due to spatially rapid changes of slip on the fault and/or a formation of tensile fractures. 相似文献
117.
A series of in-situ high temperature infrared (IR) measurements of water in an agate sample and in a milky quartz has been conducted in order to understand the nature of water in silica at high temperatures (50–700?°C) and the dehydration behavior. IR absorption bands of water molecules trapped in the milky quartz showed a systematic decrease in intensities and a shift from 3425?cm?1 at 50?°C toward 3590?cm?1 at 700?°C without any loss of water. This indicates a change in IR absorption coefficients corresponding to different polymeric states of water at different temperatures. The broad 3430?cm?1 band in the agate sample also showed a systematic decrease in IR intensity and a band shift toward higher frequency with increasing temperature (~700?°C). This indicates that the agate sample also contains fluid inclusion-like water. For this agate sample, a dehydration of loosely hydrogen-bonded molecular water occurred at lower temperatures (<200?°C). At higher temperatures (>400?°C), sharp bands around 3660 and 3725?cm?1 (3740?cm?1 at 50?°C) due to surface silanols, appeared. This indicates dehydration of H2O molecules that are hydrogen bonded to surface silanols. SiOH species in the agate are divided into three groups, namely SiOH group located at structural defects, surface silanols hydrogen bonded to each other and free surface silanols. Former two dehydrate below 700?°C and the dehydration rate of the SiOH at structural defects is faster than the other. IR spectra show that SiOH species decrease continuously even after the dehydration of most of H2O molecules. All these results provide realistic bases for the change in physicochemical states of different OH species in silica at high temperatures. 相似文献
118.
Kazuyuki Uehara Shin-Ichi Ito Hideo Miyake Ichiro Yasuda Yugo Shimizu Tomowo Watanabe 《Journal of Oceanography》2004,60(2):397-409
During November 2000–June 2002, both direct current measurements from deployment of a line of five moorings and repeated CTD
observations were conducted along the Oyashio Intensive observation line off Cape Erimo (OICE). All the moorings were installed
above the inshore-side slope of the Kuril-Kamchatka Trench. Before calculating the absolute volume transports, we compared
vertical velocity differences of relative geostrophic velocities with those of the measured velocities. Since both the vertical
velocity differences concerned with the middle three moorings were in good agreement, the flows above the continental slope
are considered to be in thermal wind balance. We therefore used the current meter data of these three moorings, selected among
all five moorings, to estimate the absolute volume transports of the Oyashio referred to the current meter data. As a result,
we estimated that the southwestward absolute volume transports in 0–1000 db are 0.5–12.8 × 106 m3/sec and the largest transport is obtained in winter, January 2001. The Oyashio absolute transports in January 2001, crossing
the OICE between 42°N and 41°15′ N from the surface to near the bottom above the continental slope, is estimated to be at
least 31 × 106 m3/sec.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
119.
Shin-Ichi Ito Kazuyuki Uehara Takashi Miyao Hideo Miyake Ichiro Yasuda Tomowo Watanabe Yugo Shimizu 《Journal of Oceanography》2004,60(2):425-437
An observation line along the TOPEX/POSEIDON (T/P) ground track 060 was set to estimate the Oyashio transport. We call this
line the OICE (Oyashio Intensive observation line off-Cape Erimo) along which we have been conducting repeated hydrographic
observations and maintaining mooring systems. T/P derived sea surface height anomaly (SSHA) was compared with velocity and
transport on OICE. Although the decorrelation scale of SSHA was estimated at about 80–110 km in the Oyashio region, the SSHA
also contains horizontal, small-scale noise, which was eliminated using a Gaussian filter. In the comparison between the SSHA
difference across two selected points and the subsurface velocity measured by a moored Acoustic Doppler Current Profiler (ADCP),
the highest correlation (0.92) appeared when the smoothing scale was set at 30 km with the two points as near as possible.
For the transport in the Oyashio region, the geostrophic transport between 39°30′ N and 42°N was compared with the SSHA difference
across the same two points. In this case the highest correlations (0.79, 0.88 and 0.93) occurred when the smoothing scale
was set at 38, 6 and 9 km for reference levels of 1000, 2000 and 3000 db, respectively. The annual mean transport was estimated
as 9.46 Sv in the 3000 db reference case. The Oyashio transport time series was derived from the T/P SSHA data, and the transports
are smaller than that estimated from the Sverdrup balance in 1994–1996 and larger than that in 1997–2000. This difference
is consistent with baroclinic response to wind stress field.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
120.
Richard Saunders Rüdiger Kneissl Keith Grainge William F. Grainger Michael E. Jones Alessia Maggi Rhiju Das † Alastair C. Edge Anthony N. Lasenby G. G. Pooley Shigeru J. Miyoshi Taisuke Tsuruta Koujun Yamashita Yuzuru Tawara Akihiro Furuzawa Akihiro Harada Izamu Hatsukade 《Monthly notices of the Royal Astronomical Society》2003,341(3):937-940