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121.
Analcime has been synthesized from natural rhyolitic tuff and green tuff (Miocene age) at 200° C and 20 kg/cm2 with solution of Na2SiO3 (12%) in 50- to 260-hr runs. From the diffraction intensities, it was found that the alteration products of green tuff contained more analcime than those of rhyolitic tuff. It has been concluded that the lithological character of starting materials and the chemical behavior of reaction products are important controlling factors in analcimization. 相似文献
122.
Gabbro — quartz diorite inclusions, angular to rounded and up to 20 cm in size, have been found as accidental fragments in a mud flow of the Okata basalt group, O-shima Island and in a tuff breccia, Hakone. New analyses are represented for seventeen inclusions and three pyroxenes. It is reasonable to conclude from petrographic and chemical features that the olivine gabbro inclusions were produced by crystal settling from a quartztholeiite magma at the early stage of fractionation within a magma reservior. On the other hand, gabbro and quartz gabbro inclusions are fragments of a small intrusive body within the Tertiary volcanic formation and consist of various amounts of cumulus phases and liquid. Quartz diorite inclusions are also fragments of a plutonic equivalent, but represents a strongly-differentiated liquid phase of the quartz-tholeiite magma. 相似文献
123.
The northeastern Japan forms a typical arcuate structure with a remarkable zonal arrangement of many geologic features, including the distribution of Quaternary volcanoes. Thus two distinct zones of volcanoes are noted here: i. e., Nasu zone on the east and Tyokai zone on the west. Some of the volcanoes of Nasu zone are characterized by the presence of pumice flows or pumice falls, sometimes of very large scales. These pumice flows belong to the calc-alkali rock series. While pumice flows or falls are rare in the Tyokai zone, where they are present though on small scale. Migration of the center of activity is noted along linear fissures, running either from east to west, or north to south at some volcanoes of Nasu zone, and consequently large swarms of volcanoes are common in this zone. While central eruption with definite center is typical of the Tyokai zone. From the petrographical and petrochemical study on the lavas and pyroclastics the original magma of the Nasu zone is estimated to be tholeiitic, and that of the Tyokai zone high-alumina basaltic. Abundant calc-alkali rocks are derived from these parental magmas. Thus the difference in the volcanic activity should be ascribed to the different nature of the parental magmas or the magmas derived from them. 相似文献
124.
Eddy activities of the surface layer in the western North Pacific detected by satellite altimeter and radiometer 总被引:5,自引:0,他引:5
Geosat radar altimeter data during the first year (from November 1986 to November 1987) of its Exact Repeat Mission are analyzed to estimate the eddy kinetic energy and propagation characteristics of anomalies of sea surface dynamic topography (SSDT) for the western North Pacific. SSDT anomalies are compared with anomalies of sea surface temperature (SST) derived from NOAA satellite radiometer data. The eddy kinetic energy (K
e
) is large in the Kuroshio stationary meander region and Kuroshio Extension region. In the downstream region of the Kuroshio Extension,K
e
is especially large on the upstream and downstream sides of prominent bathymetric features. In the interior region of the subtropical gyre is found a zonal tongue of largeK
e
at around 20–20°N. Westward propagation is dominant in the SSDT and SST anomaly field at mid-latitudes. Longitude-time lag correlation diagrams reveal the coincidence of SSDT and SST anomalies statistically, which fact suggests the baroclinic nature of the anomalies. Zonal phase speeds of SSDT anomalies are approximately equal to the theoretical speeds of baroclinic first-mode long Rossby waves, but the meridional variation of observed phase speeds does not follow the simple theoretical variation of decreasing speeds monotonously with increasing latitudes. 相似文献
125.
A rate‐dependent constitutive model of high damping rubber bearings: modeling and experimental verification 下载免费PDF全文
Yong Yuan Wei Wei Ping Tan Akira Igarashi Hongping Zhu Hirokazu Iemura Tetsuhiko Aoki 《地震工程与结构动力学》2016,45(11):1875-1892
In this study, a constitutive model of high damping rubber bearings (HDRBs) is developed that allows the accurate representation of the force–displacement relationship including rate‐dependence for shear deformation. The proposed constitutive model consists of two hyperelastic springs and a nonlinear dashpot element and expresses the finite deformation viscoelasticity laws based on the classical Zener model. The Fletcher–Gent effect, manifested as high horizontal stiffness at small strains and caused by the carbon fillers in HDRBs, is accurately expressed through an additional stiffness correction factor α in the novel strain energy function. Several material parameters are used to simulate the responses of high damping rubber at various strain levels, and a nonlinear viscosity coefficient η is introduced to characterize the rate‐dependent property. A parameter identification scheme is applied to the results of the multi‐step relaxation tests and the cyclic shear tests, and a three‐dimensional function of the nonlinear viscosity coefficient η with respect to the strain, and strain rate is thus obtained. Finally, to investigate the accuracy and feasibility of the proposed model for application to the seismic response assessment of bridges equipped with HDRBs, an improved real‐time hybrid simulation (RTHS) test system based on the velocity loading method is developed. A single‐column bridge was used as a test bed and HDRBs was physically tested. Comparing the numerical and RTHS results, advantage of the proposed model in the accuracy of the predicted seismic response over comparable hysteretic models is demonstrated. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
126.
At a time when the concept of ‘human and environmental symbiosis’ has taken on much significance, protection of suburban forests
(i.e. forests adjacent to or near developed areas) is a topic that has drawn much attention. Suburban forests have, since
ancient times, been places where people have gathered firewood and cultured trees. As a result, the vegetation of suburban
forests is only partially natural and continues to change as the forms of human activity in and around them changes. Accurate
forecasts of how suburban forests will change are, therefore, an important element in the debate over how to protect them.
In this study, a suburban forest was analyzed with laser radar sensing, multi-spectrum scanning, digital photogrammetry analysis,
aerial photograph interpretation, and a field survey. Data gathered using these techniques were compiled on a GIS to forecast
future changes in the forest. Aerial photographs taken over the past 50 years were analyzed to illuminate changes in the forest
over that period. Specifically, comparisons of precise Digital Elevation Models (DEMs) measured by using digital photogrammetry
workstations made it possible to estimate growth in forest height. The possible future conversion of such results to estimates
of amounts of carbon dioxide consolidated by forests should be very significant for discussions of global environmental problems.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
127.
Acoustic properties of deformed rocks in the Nobeoka thrust,in the Shimanto Belt,Kyushu, Southwest Japan 下载免费PDF全文
Yoshitaka Hashimoto Shogo Abe Hiroki Tano Gaku Kimura Asuka Yamaguchi Rina Fukuchi Jun Kameda Yohei Hamada Yujin Kitamura Koichiro Fujimoto Mio Eida 《Island Arc》2017,26(4)
Laboratory measurements for compressional and shear wave velocities (Vp and Vs, respectively) and porosity were conducted with core samples from the Nobeoka Thrust Drilling Project (NOBELL) under controlled effective pressure (5–65 MPa at 5 MPa intervals) and wet conditions. Samples were classified according to deformation texture as phyllite, foliated cataclasite, or non‐foliated cataclasite. Measured values of Vp, Vs, and porosity are within a range of 5.17–5.57 km/s, 2.60–2.71 km/s, and 2.75–3.10 %, respectively, for phyllite; 4.89–5.23 km/s, 2.46–2.57 km/s, and 3.58–4.53 %, respectively, for foliated cataclasite; and 4.90–5.32 km/s, 2.51–2.63 km/s, and 3.79–4.60 %, respectively, for non‐foliated cataclasite, which are all consistent with the previous laboratory experiments conducted with outcrop samples under dry conditions. However, our results also indicate higher Vp and Vs and lower porosity than those measured by the previous studies that adopted the wire‐line logging methods. The variations in Vp, Vs, and porosity are controlled by deformation structure and are greater for phyllite and foliated cataclasite than for non‐foliated cataclasite. 相似文献
128.
Shogo Aoki Kazumasa Aoki Kentaro Chiba Shuhei Sakata Yuta Tsuchiya Daichi Kato 《Island Arc》2020,29(1)
Zircon U–Pb dating of the Tonaru metagabbro body in the Sanbagawa metamorphic belt, southwest Japan, suggests that igneous events at ca 200–180 Ma were involved in the protolith formation. The trace element compositions of the Tonaru zircons are enriched in U (a fluid‐mobile element) and Sc (an amphibole‐buffered element), and depleted in Nb (a fluid‐immobile element), suggesting that the parental magmas related to the Tonaru metagabbros formed in an arc setting. Integration of our results with previous studies of the metasedimentary rocks in the Tonaru body clearly indicates that the protoliths of the Tonaru body were produced by oceanic‐arc magmatism. With the previous geochronological and geological studies, the tectono‐magmatic–metamorphic history of the Tonaru and other mafic bodies in the Sanbagawa metamorphic belt may be summarized as follows: (i) the protolith formation by the oceanic‐arc magmatic event had occurred at 200–180 Ma; (ii) the protoliths were accreted in the trench at ca 130–120 Ma; and (iii) they were completely subducted into the depth of the eclogite‐facies condition after 120 Ma. 相似文献
129.
Kurtulus Atasever Shogo Inanaga Toru Takeuchi Yuki Terazawa Oguz C. Celik 《地震工程与结构动力学》2020,49(15):1640-1661
There has been an increasing interest in using residual deformation as a seismic performance indicator for earthquake resistant building design. Self-centering braced structural systems are viable candidates for minimizing residual deformations following a major earthquake. Hence, this study proposes an alternative type of buckling restrained brace (BRB) with externally attached posttensioned (PT-BRB) carbon fiber composite cables (CFCCs). The steel core of the brace is used as an energy dissipator, whereas the CFCCs provide the self-centering force for minimizing residual story drifts. Three proof-of-concept specimens are designed, fabricated, and cyclically tested at different posttensioning force levels. The CFCC behavior to obtain cyclic response, including the anchorage system, is examined closely. A parametric study is also conducted to show the effect of the different configurations of PT-BRBs on the inelastic response. Furthermore, optimal brace parameters are discussed to realize design recommendations. The results indicated that the implementation of partially self-centering BRBs in building frames can lead to the target residual displacements. A stable behavior is obtained for the proposed PT-BRBs when subjected to the loading protocol specified in the American Institute of Steel Construction (AISC) 2016 Seismic Provisions. 相似文献
130.
Hideyuki Nakano Hiroyuki Tsujino Kei Sakamoto Shogo Urakawa Takahiro Toyoda Goro Yamanaka 《Journal of Oceanography》2018,74(4):393-420
The climatologies and variabilities of the fronts associated with the Kuroshio Extension (KE), the Kuroshio Extension Northern Branch (KENB), the flow along the Subarctic Boundary (SAB), and the Subarctic Current (SAC) are identified by a new method based on the absolute dynamic height product from the archiving, validation, and interpretation of satellite oceanographic data (the AVISO product). The fronts are detected by examining the specific contour values of the absolute dynamic topography (ADT) in the AVISO product. The (time-varying) specific contour values are decided from the local maxima of the averaged surface geostrophic velocity along the ADT. Assuming the specific contours as the front locations, we obtain an occurrence frequency map of the four front locations, and determine the monthly variability of the fronts over the 1993–2015 period. The results are validated by hydrographic observations. The KE and KENB east of the Shatsky Rise migrate southward several times at a speed of ~ 0.2 cm s?1, while the SAB and SAC are mostly stationary. 相似文献