Laboratory analogy of crystalline enstatite grain formation in plasma field     

T. Sato  K. Kamitsuji  Y. Kimura  O. Kido  Y. Saito 《Planetary and Space Science》2006,54(6):617-620

Crystalline enstatite (MgSiO₃) grains were produced by the simultaneous evaporation of SiO grains and Mg vapor in a plasma field. The MgSiO₃ grains were spherical or needlelike. The necessity of a plasma field in astromineralogy is suggested in the present study.  相似文献   

Elastic Boundary Conditions In Long-Period Core Oscillations   总被引：4，自引：0，他引：4  

D. E. Smylie  A. M. K. Szeto  Kachishige Sato 《Geophysical Journal International》1990,100(2):183-192

  相似文献   

The formation of todorokite and birnessite in sea water pumped from under ground     

N Takematsu  Y Sato  S Okabe 《Geochimica et cosmochimica acta》1984,48(5):1099-1106

Manganese oxides precipitated from aerated well sea water at the Marine Science Museum, Tokai University, have been analyzed chemically and mineralogically. The $\text{O}\text{Mn}$ ratios are lower in todorokite than in birnessite but these minerals have similar contents of minor transition metals, which can be taken up additionally from sea water after the precipitation of Mn oxides. On the basis of these results, the genesis of Mn minerals is discussed in relation to marine Mn nodules.  相似文献   

Dynamic behaviour and identification of non-uniform ground by the discrete wave number method     

Kenzo Toki  Tadanobu Sato 《Soil Dynamics and Earthquake Engineering》1987,6(2)

Powell's method for minimizing a function of several variables without calculating derivatives is applied to recorded earthquake motion on the ground surface to identify ground characteristics that have irregular profiles. The identifications are made by designating the shear wave velocity depth and width of the irregularity of surface ground as unknown parameters and are based on the least square fit between the amplitude of the transfer function determined from accelerograms recorded at two observation sites and the corresponding transfer function calculated from the response analysis of a ground model. The discrete wave number method is used to analyze the response of ground with a non-uniform profile for the incidence of SH waves. The effect of the initial assumed values on the convergence is studied by evaluating the square error between the theoretical transfer function and that calculated from the parameters identified. The dispersive trend found for the accelerograms is explained by the calculated response of a ground model with a non-uniform profile.  相似文献   

Separation and sliding between soil and structure during strong ground motion     

Kenzo Toki  Tadanobu Sato  Fusanori Miura 《地震工程与结构动力学》1981,9(3):263-277

This paper presents an approach to the problem of separation and sliding between soil and structure in the finite element analysis of dynamic soil-structure interaction problems. Joint elements are arranged along the contact surface between soil and structure and they have a property such that tensile forces are not transmitted between the planes representing structure and soil in the finite element analysis. The dynamic properties governing the sliding are determined by the Mohr-Coulomb failure law determined from the cohesion and the friction angle between soil and structure. The proposed method is applied to (i) a model of a reactor building resting on the free surface of layered ground and (ii) a buried foundation structure. The numerical computations reveal the following results: that the translation is dominant in the motion of the structure when sliding is taking place between soil and structure, and that the rocking is dominant in the rest of the response. The amplitude of the response during sliding is increased on any one point of the structure and decreased on any one point of the ground compared with that of the fixed condition at the interface. In the case of the buried structure, it is observed in the computed results that the structure and soil move in the opposite direction along the vertical contact surface and are separated from each other in the near surface region during the strong phase of the excitation.  相似文献   

A spectroscopic study of Epsilon Aurigae     

Mamoru Saitō  Shusaku Kawabata  Keiich Saijo  Hideo Sato 《Astrophysics and Space Science》1984,99(1-2):269-272

Epsilon Aurigae has been observed during ingress and totality between 1982 and 1983 at Okayama. Analyses of profiles of H line and of radial velocities of neutral hydrogen and metals show that the secondary component consists of at least three parts in structure.Paper presented at the Lembang-Bamberg IAU Colloquium No. 80 on Double Stars: Physical Properties and Generic Relations, held at Bandung, Indonesia, 3–7 June, 1983.  相似文献   

On the 3/1 planar and circular resonant problem     

Tadashi Yokoyama  Massae Sato 《Celestial Mechanics and Dynamical Astronomy》1986,39(2):117-132

The simplest model of a resonant problem of second order is the planar and circular case. Simplification like this is very old and for 3/1 resonance, several authors have studied this problem with different purposes. In this work, we test this model for the available asteroids, by applying Hori's perturbation method. Explicit solutions of the intermediate orbit are obtained. In the plane of two constants of the problem, all types of motion are described. By testing the model, it is shown that, in general, one can confirm results of numerical integrations indicating libration for a few number of asteroids and circulation for most of them. However, agreement in numerical values for amplitude and period of librations seems to be not possible mainly if Jupiter's eccentricity is neglected. On the other hand, even though there might be some physical reasons determining that only asteroids with high eccentricity may librate, it is shown that, from mathematical point of view, libration may occur even in the case of small eccentricities provided that some relations are satisfied.  相似文献   

Deep seismic reflection profiling across the Ou Backbone range, northern Honshu Island, Japan     

Hiroshi Sato  Naoshi Hirata  Takaya Iwasaki  Makoto Matsubara  Takeshi Ikawa   《Tectonophysics》2002,355(1-4)

Knowledge of the crustal structure, especially the geometry of seismogenic faults, is key to understanding active tectonic processes and assessing the size and frequency of future earthquakes. To reveal the relationship between crustal structure and earthquake activity in northern Honshu Island, common midpoint (CMP) deep reflection profiling and earthquake observations by densely deployed seismic stations were carried out across the active reverse faults that bound the Ou Backbone range. The 40-km-long CMP profiles portray a relatively simple fault geometry within the seismogenic layer. The reverse faults merge at a midcrustal detachment just below the base of the seismogenic layer, producing a pop-up structure that forms the Ou Backbone range. The top of the reflective middle to lower crust (4.5 s in travel time (TWT)) nearly coincides with the bottom of seismogenic layer. The P-wave velocity structure and surface geology suggest that the bounding faults are Miocene normal faults that have been reactivated as reverse faults.  相似文献   

Seismological features of island arc crust as inferred from recent seismic expeditions in Japan     

Takaya Iwasaki  Toshikatsu Yoshii  Tanio Ito  Hiroshi Sato  Naoshi Hirata 《Tectonophysics》2002,355(1-4)

Crustal studies within the Japanese islands have provided important constraints on the physical properties and deformation styles of the island arc crust. The upper crust in the Japanese islands has a significant heterogeneity characterized by large velocity variation (5.5–6.1 km/s) and high seismic attenuation (Qp=100–400 for 5–15 Hz). The lateral velocity change sometimes occurs at major tectonic lines. In many cases of recent refraction/wide-angle reflection profiles, a “middle crust” with a velocity of 6.2–6.5 km/s is found in a depth range of 5–15 km. Most shallow microearthquakes are concentrated in the upper/middle crust. The velocity in the lower crust is estimated to be 6.6–7.0 km/s. The lower crust often involves a highly reflective zone with less seismicity, indicating its ductile rheology. The uppermost mantle is characterized by a low Pn velocity of 7.5–7.9 km/s. Several observations on PmP phase indicate that the Moho is not a sharp boundary with a distinct velocity contrast, but forms a transition zone from the upper mantle to the lower crust. Recent seismic reflection experiments revealed ongoing crustal deformations within the Japanese islands. A clear image of crustal delamination obtained for an arc–arc collision zone in central Hokkaido provides an important key for the evolution process from island arc to more felsic continental crust. In northern Honshu, a major fault system with listric geometry, which was formed by Miocene back arc spreading, was successfully mapped down to 12–15 km.  相似文献   

南极中山站午后极光强度与太阳风参数的关系          下载免费PDF全文

胡红桥  刘瑞源  杨惠根  王敬芳  Natsuo Sato  Masayu kiKikuchi  李升贵 《极地研究》2001,13(3):151-158

本文利用1997年和1998年南极中山站多通道扫描光度计的地面观测数据和WIND卫星在弓激波上游对太阳风参数的观测数据，对午后高纬极光强度与太阳风等离子体密度、动压以及太阳风速度之间的相关性进行了定量研究。研究表明，午后极光630．0nm的强度与太阳风等离子体参数之间有较好的相关，630．0nm的强度表现出随太阳风等离子体密度、动压和速度的增大而增加的趋势，其相关系数分别为0．84、0．88和0．61；而557．7nm极光的强度与太阳风等离子体参数之间的相关较差。午后557．7nm极光的强度与太阳风等离子体参数之间的相关较差。午后557．7nm和630．0nm对太阳风参数的不同响应表明太阳风对630．0nm影响更直接，而557．7nm受到了磁层动力学过程的影响。  相似文献