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1.
Gas-liquid chromatographic method byGehrke
et al. was applied to the determination of the dissolved proteinaceous substace. Sea-water samples were evaporated in vacuum to the volume of one twentieth of the initial volume and separated from deposited inorganic salt crystals. Thirteen kinds of amino acids except histidine, arginine and cystine were quantitatively determined for artificial sea water containing sixteen standard amino acids with accuracy of about five percent and with yield of 80 to 103 percent. This method has advantage comparing with paper or thin layer chromatography on the precision and comparing with ion-exchange method on sensitivity.The difference of amino acid concentration between the sea-water samples of different depth and different region was observed. The total amounts of dissolved amino acids were found to be between 33 and 92g per liter in sea water of Pacific Ocean taken at the surface to 1,500 m in depth.Contribution No. 41, from The Research Institute of North Pacific Fisheries, Hokkaido University. 相似文献
2.
We theoretically study the scattering ofP, SV andSH waves by a zonal distribution of cracks, which simulates a fault fracture zone. An investigation is conducted how the geometrical properties of the crack distribution and the frictional characteristics of the crack surface are reflected in the attenuation and dispersion of incident waves, as well as in the amplitudes of the transmitted and reflected waves from the zone. If the crack distribution within the fault zone changes temporally during the preparation process of the expected earthquake, it will be important for earthquake prediction to monitor it, utilizing the scattering-induced wave phenomena.We consider the two-dimensional problem. Aligned cracks with the same length are assumed to be randomly distributed in a zone with a finite width, on which elastic waves are assumed to be incident. The distribution of cracks is assumed to be homogeneous and sparse. The crack surface is assumed to be stress-free, or to undergo viscous friction; the latter case simulates fluid-filled cracks. The opening displacement of the crack is assumed to be negligibly small. The idea of the mean wave formalism is employed in the analysis, and Foldy's approximation is assumed.When the crack surface is stress-free, it is commonly observed for every wave mode (P, SV andSH) that the attenuation coefficientQ
–1 peaks aroundka1, the phase velocity is almost independent ofk in the rangeka<1 and it increases monotonically withk in the rangeka>1, wherek is the intrinsicS wavenumber anda is the half length of the crack. The effect of the friction is to shift the peak ofQ
–1 and the corner of the phase velocity curve to the low wavenumber range. The high wavenumber asymptote ofQ
–1 is proportional tok
–1 independently of model parameters and the wave modes. If the seismological observation thatQ
–1 ofS waves has a peak at around 0.5 Hz in the earth's crust is combined with our results, the upper limit of crack size within the crust is estimated about 4 km. The information regarding the transmitted and reflected waves, such as the high wavenumber limit of the amplitude of the transmitted wave etc., allows estimation of the strength of the friction. 相似文献
3.
Ismail Husain Fathi Kaoru Miyashita Jun Kawahara 《Arabian Journal of Geosciences》2013,6(8):3111-3118
We adopted the seismic tomography technique to refine the three-dimensional velocity structure model of the western part of Hokkaido, Japan. Using the P-wave first arrival data listed by Japan Meteorological Agency from 2002 to 2005, we could estimate a 3-D inhomogeneous velocity structure model with a low velocity at a depth of 14 km beneath Asahikawa. The crustal structure near Sapporo was characterized by lateral velocity change toward the southern seaside. The low-velocity zone near Urakawa, proposed by previous research, was also clarified. In general, the present model showed lower-velocity values for most of the crustal layers in the area concerned. The results of this study were affected by less number of higher magnitude events (M?≥?0.5) in the central part of the area of interest. However, the perturbation results for comparatively shallow layers (6–50 km) were good in resolution. It was found that the source region of the Rumoi–Nanbu earthquake of December 14, 2004 was characterized by a low-velocity zone, located between high velocity zones. Such an inhomogeneous crustal structure might play an important role in the relatively high seismic activity in the Rumoi–Nanbu earthquake source region. 相似文献
4.
The purpose of this paper is to investigate the estimation of dynamic elastic behavior of the ground using the Kalman filter finite element method. In the present paper, as the state equation, the balance of stress equation, the strain–displacement equation and the stress–strain equation are used. For temporal discretization, the Newmark ¼ method is employed, and for the spatial discretization the Galerkin method is applied. The Kalman filter finite element method is a combination of the Kalman filter and the finite element method. The present method is adaptable to estimations not only in time but also in space, as we have confirmed by its application to the Futatsuishi quarry site. The input data are the measured velocity, acceleration, etc., which may include mechanical noise. It has been shown in numerical studies that the estimated velocity, acceleration, etc., at any other spatial and temporal point can be obtained by removing the noise included in the observation. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
5.
Arsenic contamination of ground and pond water and water purification system using pond water in Bangladesh 总被引：1，自引：0，他引：1
H. Yokota K. Tanabe M. Sezaki Y. Akiyoshi T. Miyata K. Kawahara S. Tsushima H. Hironaka H. Takafuji M. Rahman Sk. A. Ahmad M. H. S. U. Sayed M. H. Faruquee 《Engineering Geology》2001,60(1-4):323-331
This paper, firstly, shows the distribution of arsenic-contaminated groundwater in Samta village. This village, which is in Jessore district in Bangladesh, was chosen as a model village for investigating the mechanism of groundwater contamination. 90% of the tube wells in this village had arsenic concentrations above the Bangladesh standard of 0.05 mg/l. Tube wells with arsenic concentrations of over 0.50 mg/l were distributed in the southern part of the village with a belt-like shape from east to west. Secondly, groundwater distribution is discussed with respect to its flow and the high arsenic zone (As≥0.50 mg/l) agrees well with the drifting zone of the groundwater. Furthermore, arsenic-free water supply systems suitable for a small area in the village have been developed. A pond sand filter (PSF) system which purifies pond water is discussed in this paper. Prior to the construction of the PSF, the water quality in ponds was examined for arsenic levels. The inflow of drainage from the tube wells was found to be the major cause of arsenic contamination of pond water. The PSF installed in Samta is working very well and produces a good quality of treated water. 相似文献
6.
7.
Spectral ratios of teleseismic P waves for 15 deep (>200 km) earthquakes recorded at 146 High-Sensitivity Seismographic Network stations in the Kanto district and its surrounding area, eastern Japan, were inverted for attenuation parameter $ t_P^{ * } $ . The dataset consisted of good-quality vertical-component seismograms, whose P phases were handpicked. The P wave spectral ratios with high signal-to-noise ratios were calculated up to 1 Hz for all the station pairs, linear regressed, and then inverted for $ t_P^{ * } $ using the technique of least squares . The result showed that the active volcanic areas were clearly characterized by high $ t_P^{ * } $ . In contrast, $ t_P^{ * } $ varied in the nonvolcanic areas. The present result on the $ t_P^{ * } $ distribution was roughly consistent with the shallow part (<30 km) of an attenuation structure, which has been previously obtained based on 3-D tomography by using records of high-frequency (around 5 Hz) P waves from local earthquakes. This suggested that the present method of $ t_P^{ * } $ estimation is valid. The advantage and possible application to other areas were also discussed. 相似文献
8.
Mutsuto Kawahara 《Advances in water resources》1982,5(4):195-207
This paper presents a finite element method for the analysis of nearshore current, which is mainly induced by surface waves. The analysis is divided into two parts, i.e., the analysis of wave and the analysis of currents. The basic equations are conservation of wave number, wave energy, momentum and continuity. The first two are for wave analysis and the last two for the current analysis. The wave angle is determined from the conservation law of wave number. Using the resulting wave angle and the conservation of wave energy, the distribution of wave height is derived. The radiation stress is derived from the wave angle and height. The nearshore current flow is obtained from the conservations of momentum and continuity including the radiation stress. All the numerical procedures are based on the finite element method. For the analysis of the wave angle and wave height, the incremental iteration method and logarithmic function formulation are employed. For the analysis of the current flow, the stream function formulation is used. From the numerical computations, it is seen that the finite element method presented in this paper is very valuable in practical applications. The method is applied to the analysis of the nearshore current flow of Twan Bay in Japan. 相似文献
9.
Mansour Ioualalen Yoshinobu Wakata Yoshikazu Kawahara Yves Gouriou David Varillon 《Journal of Oceanography》2003,59(1):105-111
The sea surface salinity (SSS) derived from a network developed at Institut de Recherche pour le Développement (IRD/Nouméa)
has been analyzed during the period 1995–1998 in the tropical western Pacific. The measurements were made with thermosalinographs
installed on merchant ships selected for their regularity and routes. The western tropical Pacific was sampled mainly along
three regular routes across the equator leading to an average of a one month frequency. We analyze here how such a network
can be efficient in monitoring the SSS at time scales longer than one month. For this purpose we have used results derived
from the Princeton Ocean Model (POM) which is forced by the surface flux of National Centers for Environmental Prediction
(NCEP) reanalysis data. The interannual variability of the simulated SSS exhibits very similar features to (sub-sampled) observations
despite its being weakly damped to a climatology in order to avoid biases. Even smaller time scale phenomena can be simulated,
like the erosion/reconstruction of the region composed of low density waters lying within the Pacific warm pool. The agreement
between the observational data and the simulations indicate that the network sampling is sufficient to monitor the SSS variability
of the western tropical Pacific from three-month to interannual time scales.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
10.
The purpose of this paper is to present a parameter identification method to determine the force of a blast and the elastic modulus of the ground using the measurements of a dynamic elastic wave, the adjoint equation method of optimal control theory, and the finite element method. Before the excavation of rocky ground, it is important to estimate the ground properties. In this paper, the elastic modulus is determined as the performance function is minimized using a technique based on the first‐order adjoint method. The performance function is a square sum of the discrepancies between the computed and the observed values of the velocities. After the determination of the magnitude of the blasting force, we can determine the elastic modulus of the rock. As the basic equation to calculate the velocities of dynamic elastic body, elastic equilibrium equations with linear viscosity are employed. The adjoint equation method has been utilized in order to calculate the gradient of the performance function with respect to the parameters. The gradient of the performance function is calculated using the first‐order adjoint equation. The weighted gradient method is applied for minimization. In order to solve the state equations in space and time, the finite element method and the Newmark $\frac{1}{4}$ method are used. In this paper, we tested the practical application of our proposed method for determination of the elastic modulus of rock at the Ikawa tunnel located in the Tokushima prefecture, Japan. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献