Direct determination of barium in Sea water by inductively coupled plasma emission spectrometry     

Masahito Sugiyama  Masakazu Matsui  Eiichiro Nakayama 《Journal of Oceanography》1984,40(4):295-302

A method for the determination of barium in sea water was investigated using inductively coupled plasma emission spectrometry, and sea water samples from the Japan Sea and the Pacific Ocean were directly analyzed by this method. Artificial sea water was used to prepare matrix matched standard solutions to overcome the problem of physical interference. The detection limit (signal/noise ratio=2) for barium in deionized and distilled water was 0.08µg l^?1 and in sea water, 0.12µg l^?1. The reproducibilities in the purified water and in the sea water at the 10µg l^?1 level were 0.7% a#FFFFFFnd 0.5%, respectively. The barium concentration in both the Japan Sea and the Pacific Ocean increased with depth and ranged between 5.5–10.0µg l^?1 and 4.1–18.4µg l^?1, respectively.  相似文献   

Gravitational N-body problem on the accretion process of terrestrial planets     

Takafumi Matsui  Hitoshi Mizutani 《Icarus》1978,34(1):146-172

Numerical integration of the gravitational N-body problem has been carried out for a variety of photoplanetary clusters in the range N = 100 to 200. Particles are assumed to coagulate at collisions irrespective of relative velocity and mass ratio of the particles. It is shown graphically how the dispersed N-bodies accumulate to a single planet through mutual collisions. The velocity distribution and size distribution of bodies are also investigated as functions of time in the accretion process. The root mean square velocity of bodies in a cluster increases with time in an early stage of accretion but decreases with time in a late stage of accretion. Accretion rates of planets are found to be dependent strongly on the initial number density distribution, the initial size distribution, and the initial velocity distribution of bodies. Formation of satellites of about 10% in the planet mass is common to most cases in the present study. A substantial mass of bodies also escapes from the cluster. Many satellites and escapers formed during the accretion process of planets may be source materials of heavy bombardment in the early history of planets.  相似文献   

Performance of Mortar and Chemical Grout Injection into Surrounding Soil When Slurry Pipe-jacking Method is Used   总被引：1，自引：0，他引：1  

Hideki Shimada  Takashi Sasaoka  Saeid Khazaei  Yasuhiro Yoshida  Kikuo Matsui 《Geotechnical and Geological Engineering》2006,24(1):57-77

Small-diameter shallow tunnels are often being built by using the slurry pipe-jacking method. This system involves the pushing or thrusting of a drivage machine and concrete pipes into the ground. Chemical grout injection into the surrounding soil around the tunnel is carried out after the drivage and pushing processes are finished. The purpose of the chemical grout injection is to maintain permanent stability of the surrounding soil. However, the behavior of the chemical grouting material in the surrounding soil around the tunnel and the amount of optimum injection is not clearly understood. From these points of view, this paper discusses the performance of the chemical grouting material, when it is injected into the surrounding soil around the tunnel, by means of 2-D Eulerian–Lagrangian seepage analysis. Moreover, the effectiveness of the chemical grout injection was evaluated by using the non-linear finite element method. This investigation show when the range of the grouted zone is designed; it is necessary that the relationship between Young’s modulus of the soil/grouted zone and the confining stress be taken into consideration in order to establish effective, economical and safe chemical grout injection system. Understanding the performance of the seepage/dispersion behavior of the chemical grout and the characteristics of soil/ grouted zone is also important.  相似文献   

Real Time Analysis and Forecasting of Strata Caving Behaviour during Longwall Operations     

S. Tadisetty  K. Matsui  H. Shimada  R. N. Gupta 《Rock Mechanics and Rock Engineering》2006,39(4):383-393

Summary. Discontinuous manual observations and irregular caving characteristics of roof rocks often lead to improper decisions resulting in accidents and production loss. Hence, systematic monitoring of the hanging roof behind the chock shields is necessary for safe and productive mining operations. A real-time application was successfully implemented in an Indian mine for forecasting of hanging roof behaviour to enhance safety and productivity. This paper reports the functioning of real-time TWAP (time weighted average pressure) analysis in the forecasting of hanging roof behaviour in real time.  相似文献   

Monitoring of Over Cutting Area and Lubrication Distribution in a Large Slurry Pipe Jacking Operation   总被引：1，自引：0，他引：1  

Saeid Khazaei  Hideki Shimada  Takashi Kawai  Junichi Yotsumoto  Kikuo Matsui 《Geotechnical and Geological Engineering》2006,24(3):735-755

Slurry pipe jacking was firmly established as a special method for the non-disruptive construction of the underground pipelines of sewage systems. Pipe jacking, in its traditional form, has occasionally been used for short railways, roads, rivers, and other projects. Basically the system involves the pushing or thrusting of concrete pipes into the ground by a number of jacks. In slurry pipe jacking, during the pushing process, mud slurry and lubricant are injected into the face and the over cutting area that is between the concrete pipes and the surrounding soil. Next, the slurry fills voids and the soil stabilizes due to the created slurry cake around the pipes. Fillings also reduce the jacking force or thrust during operation. When the drivage and pushing processes are finished, a mortar injection into the over cutting area is carried out in order to maintain permanent stability of the surrounding soil and the over cutting area. Successful lubrication around the pipes is extremely important in a large diameter slurry pipe jacking operation. Control of lubrication and gaps between pipes and soil can prevent hazards such as surface settlement and increases in thrust. Also, to find voids around the pipes after the jacking process, in order to inject mortar for permanent stabilizing, an investigation around the pipes is necessary. To meet these aims, this paper is concerned with the utilization of known methods such as the GPR (Ground Penetrating Radar) system and borehole camera to maintain control of the over cutting area and lubricant distribution around the pipes during a site investigation. From this point of view, experiments were carried out during a tunnel construction using one of the largest cases of slurry pipe jacking in Fujisawa city, Japan. The advantages and disadvantages of each system were clarified during the tests.  相似文献   

MHD Dynamo Simulation Using the GeoFEM Platform: Comparison with a Spectral Method     

Hiroaki Matsui  Hiroshi Okuda 《Pure and Applied Geophysics》2004,161(11-12):2199-2212

— We investigate differences of results of a MHD dynamo simulation using the finite-element method (FEM) with that by the spherical harmonics expansion. The simulation was performed with a total of 7.8×10⁴ elements in the simulation domain. The results show that the magnetic energy is generated approximately four times of the kinetic energy in both cases. The outline of present results has consistence with that by the spectral method. However, small-scale patterns can be observed in the spectral method case. These discrepancies are caused by limitation of the spatial resolution in both of the present simulations.  相似文献   

Molecular dynamics study of MgSiO3 perovskite     

Masanori Matsui 《Physics and Chemistry of Minerals》1988,16(3):234-238

  相似文献   

Preliminary results of a study on the responses of sedimentary rocks to shaft excavation     

Kozo Sugihara  Hisaya Yoshioka  Hiroya Matsui  Toshinori Sato 《Engineering Geology》1993,35(3-4):223-228

A shaft with a diameter of 6 m and a depth of 150 m was excavated in sedimentary rocks. Anin situ study was carried out to identify the size and rock properties of the zone disturbed by the excavation and to estimate the applicability of existing methods for measuring and modelling such a zone. The study detected displacements and changes in the properties of the rock within about 1 m of the shaft wall. Numerical analysis using a model of continuous rock mass can simulate some features of disturbance due to excavation, although slight discrepancies exist between the measured and analysed results. The excavation disturbance detected in this study is probably due to fracturing, the redistribution of stress and undersaturation. However, the relationships between the disturbance due to excavation and these processes have not been quantified. The existing methods for measurements and numerical analysis can provide important information on the disturbance due to excavation but need to be improved to understand disturbance due to excavation further.  相似文献   

Diffusive Shock Acceleration of Electrons at an Interplanetary Shock Observed on 21 Feb 1994     

N. Shimada  T. Terasawa  M. Hoshino  T. Naito  H. Matsui  T. Koi  K. Maezawa 《Astrophysics and Space Science》1998,264(1-4):481-488

  相似文献   

Transient crater growth in granular targets: An experimental study of low velocity impacts into glass sphere targets     

Satoru Yamamoto  Koji Wada  Takafumi Matsui 《Icarus》2006,183(1):215-224

We experimentally studied the formation and collapse processes of transient craters. Polycarbonate projectiles with mass of 0.49 g were impacted into the soda-lime glass sphere target (mean diameters of glass spheres are ∼36, 72, and 220 μm, respectively) using a single-stage light-gas gun. Impact velocity ranged from 11 to 329 m s⁻¹. We found that the transient crater collapses even at laboratory scales. The shape (diameter and depth) of the transient crater differs from that of the final crater. The depth-rim diameter ratios of the final and transient craters are 0.11-0.14 and 0.26-0.27, respectively. The rim diameter of both the transient and final crater depends on target material properties; however, the ratio of final to transient crater diameter does not. This suggests that target material properties affect the formation process of transient craters even in the gravity regime, and must be taken into account when scaling experimental results to planetary scales. By observing impacts into glass sphere targets, we show that although the early stage of the excavation flow does not depend on the target material properties, the radial expansion of the cavity after the end of vertical expansion does. This suggests that the effect of target material properties is specifically important in the later part of the crater excavation and collapse.  相似文献