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1.
Yoshimasa Hosokawa 《Astrophysics and Space Science》1985,115(2):403-407
Dynamics of the apsidal motion in close binary systems are discussed. A comparison between the solution for the perfect fluid system and the solution for the rigid system reveals that some overall viscosity in the interior of distorted star has a right tendency to reconcile the observation of apsidal motion with the theory of internal structure. 相似文献
2.
Konstantin V. Lebedev Max Yaremchuk Humio Mitsudera Iwao Nakano Gang Yuan 《Journal of Oceanography》2003,59(6):751-763
A finite-difference quasigeostrophic (QG) model of an open ocean region has been employed to produce a dynamically constrained
synthesis of acoustic tomography and satellite altimetry data with in situ observations. The assimilation algorithm is based upon the 4D variational data interpolation scheme controlled by the model's
initial and boundary conditions. The data sets analyzed include direct and differential travel times measured at the array
of five acoustic transceivers deployed by JAMSTEC in the region of the Kuroshio Extension in 1997, Topex/Poseidon altimetry,
CTD soundings, and ADCP velocity profiles. The region monitored is located within the area 27.5°–36.5°N, 143°–155°. The results
of assimilation show that mesoscale variability can be effectively reconstructed by five transceivers measuring direct and
reciprocal travel times supported by relatively sparse in situ measurements. The misfits between model and data lie within the observational error bars for all the data types used in assimilation.
We have compared the results of assimilation with the statistical inversion of travel time data and analyzed energy balances
of the optimized model solution. Energy exchange between the depth-averaged and shear components of the observed currents
reveals a weak decay of the barotropic mode at the rate of 0.2 ± 0.7⋅10−5 cm2/s3 due to topographic interaction. Mean currents in the region are unstable with an estimate of the available potential energy
flux from the mean current to the eddies of 4.7 ± 2.3⋅10−5 cm2/s3. Kinetic energy transition has the same sign and is estimated as 2.8 ± 2.5⋅10−5 cm2/s3. Potential enstrophy is transferred to the mesoscale at a rate of 5.5 ± 2.7⋅10−18 s−3. These figures provide observational evidence of the properties of free geostrophic turbulence which were predicted by theory
and observed in numerical experiments.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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Oceanic current data in the warm pool region of the western equatorial Pacific measured by upward-looking moored Acoustic
Doppler Current Profilers at two equatorial sites (147°E and 154°E) and two off-equatorial sites (2°N and 2°S, 156°E) during
TOGA/COARE Intensive Observing Period (IOP) from November 1992 to February 1993 are used to examine short-term variabilities
in the upper layer above 160–240 m. In time series of the zonal and meridional currents in many layers, spectral peaks are
found at periods around 2 days and 4 days in addition to high energies in a period range longer than 10 days. The signal with
the period of about 2 days has significantly high energies at all sites, and its magnitude is higher for the meridional current
than for the zonal one. This signal is especially active in the first half of IOP from November to December in 1992. In this
period, the quasi-2-day signal in the current field is coherent between northern (2°N) and southern (2°S) stations, but it
has no evident relationship with that in the surface wind field around the stations. The quasi-4-day signal with the period
of about 4 days has highest energies in layers above 160 m at the southern station, and is coherent between northern and southern
stations. Besides, the signal at the station of 2°S has a significantly high coherence with that in the wind at the southern
station, suggesting that it is a local phenomenon. 相似文献
6.
The barotropic instability of a boundary jet on a beta plane is considered with emphasis on the effect of internal viscosity.
An eigenvalue problem for the disturbance equations and its inviscid version are solved by the aid of numerical methods, and
instability characteristics are determined as functions of the Reynolds numberR for various values of the beta-parameter. Typical disturbance structures (eigenfunctions) are also computed.
Numerical examples show that the minimum critical Reynolds numberR
cr
for instability is smaller than 100. At a Reynolds number of the order of hundreds, there appears a second mode of instability
in addition to the first unstable mode originating atR
cr
; a kind of ‘resonance’ between the first and second eigenvalues occurs at the particular value ofR. The neutral stability curves are accordingly multi-looped. Although each of the two unstable modes asymptotically approaches
its inviscid counterpart asR→∞, the asymptotic approach to the inviscid limit is rather slow and the effect of varyingR is conspicuous even atR∼O (104). It is thus demonstrated that the Reynolds number is an essential stability parameter for real boundary jets.
The main part of the material contained in this paper was presented at 1981-Autumn Assembly of the Oceanographical Society
of Japan. 相似文献
7.
When river water mixes with sea water in estuary area, the concentrations of the dissolved element in river water may be changed
by either a simple physical mixing process or some complex chemical processes. It has been clarified in the Chikugogawa River
estuary area that the change in concentrations of SO
4
2−
, BO
3
3−
, Mg2+, Ca2+ and F− is only due to the mixing process but the change in concentrations of SiO
3
2−
and Al3+ is due to the chemical process in addition to the mixing process.
相似文献
8.
Partitioning of elements between majorite garnet and melt and implications for petrogenesis of komatiite 总被引:5,自引:1,他引:5
Eiji Ohtani Iwao Kawabe Junko Moriyama Yoshihiko Nagata 《Contributions to Mineralogy and Petrology》1989,103(3):263-269
Partitioning of elements between majorite garnet and ultrabasic melt has been studied at 16 GPa and 1950° C. Ca, Ti, La, Sm, Gd, Zr, Hf, Fe, Ni, Mn, K, and Na are enriched in the melt, whereas Al, Cr, V, Sc and Yb are concentrated in majorite garnet. Thus, majorite garnet fractionation by partial melting could produce chemical heterogeneities in these elements deviating from chondritic abundance. Using the partitioning behaviour of elements between majorite garnet and ultrabasic melt, the petrogenesis of komatiite is discussed. A simple model to explain the chemical varieties of komatiites is as follows. Aluminadepleted komatiite was generated by partial melting of the primitive mantle at 200–650 km depth, and alumina-enriched komatiite is the product of remelting of the residual solid at the same depths, whereas alumina-undepleted komatiite was formed by partial melting of the primitive upper mantle at depths shallower than 200 km. We suggest the possibility of large-scale chemical layering or heterogeneity in the early Archean upper mantle as an alternative model for komatiite genesis; shallower mantle depleted in majorite garnet and the underlying mantle enriched in majorite garnet. Alumina-depleted and alumina-enriched komatiites in the early Archean might be generated by a high degree of partial melting of the layered mantle. Such chemical layering could have been homogenized by the late Archean. This explains the observations that alumina-depleted and alumina-enriched komatiites were generally formed in the early Archean but alumina-undepleted komatiite was erupted in the late Archean. 相似文献
9.
A formulation for the analysis of pullout test on highly extensible planar reinforcement is presented. The non-linear differential equation for pullout mechanism was expressed in non-dimensional form and solved numerically using the Gauss–Siedel technique. Parametric study was carried out for various ranges of relative stiffnesses, and relative bond resistances. Normalized load–displacement relations and the variations of pullout force and reinforcement displacements along the length of reinforcement are presented graphically. A method for the estimation of the interface interaction parameters from a pre-failure test is also given. The numerical predictions compare well with the available experimental pullout test results for various geotextiles, polymers and nylon geosynthetics. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
10.
Sato Minoru Oba Takashi Hosokawa Takao Yamaguchi Toshiyasu Nakano Toshiki Saito Tadao Muramoto Koji Kahara T akashi Funayama Katsura Kobayashi Akio Nakano Takahisa 《中国海洋大学学报(英文版)》2005,4(3):209-213
Brown alga ( Undaria pinnatifida) was treated with alginate lyase and hydrolyzed using 17 kinds of proteases and the inhibitory activity of the hydrolysates for the angiotensin-I-converting enzyme (ACE) was measured. Four hydrolysates with potent ACE-inhibitory activity were administered singly and orally to spontaneously hypertensive rats (SHRs). The systolic blood pressure of SHRs decreases significantly after single oral administration of the brown alga hydrolysates by pro- tease S ' Amano' (from Bacillus stearothermophilus) at the concentration of 10 (mg protein) (kg body weight)^ - 1. In the 17 weeks of feeding experiment, 7-week-old SHRs were fed standard diet supplemented with the brown alga hydrolysates for 10 weeks. In SHRs fed 1.0 and 0.1% brown alga hydrolysates, elevating of systolic bloodpressure was significantly suppressed for 7 weeks. To elucidate the active components, the brown alga hydrolysates were fractionated by 1-butanol extraction and HPLC on a reverse-phase column. Seven kinds of ACE-inhibitory peptides were isolated and identified by amino acid composition analysis, sequence analysis, and LC-MS with the results Val-Tyr, Ile-Tyr, Ala-Trp, Phe-Tyr, Val-Trp, Ile-Trp, and Leu-Trp. Each peptide was determined to have an antihypertensive effect after a single oral administration in SHRs. The brown alga hydrolysates were also confirmed to decrease the blood pressure in humans. 相似文献