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81.
The role of the phase equilibrium of water in frost heave was studied for two kinds of soil. The rate of frost heave and the rate of water intake were measured simultaneously under various rates of heat removal. The experimental data revealed a trend common for both soils that the rate of water intake attains its maximum at a certain critical rate of heat removal. The data were analyzed by using equations accurately describing the relation between these rates. The results of the analysis indicate a serious doubt about the validity of phase equilibrium in the system. Alternatively, an assumption was introduced that supercooling occurred between a frost front and an unfrozen part of the soil. It was shown that supercooling could explain the data well under certain conditions. 相似文献
82.
An equation accurately describing the rate of frost heave is derived by using the mixture theory of continuum mechanics. It is shown that the rate of frost heave is determined mainly by the rate of heat removal and the rate of water intake. When the phase equilibrium holds in the system, the relation between the rate of heat removal and the rate of water intake is shown to depend mainly on the phase composition data of a given medium.By studying reported experimental data, it is found that the phase equilibrium may hold until th rate of heat removal reaches a certain critical value. When the rate of heat removal exceeds this critical value, the phase equilibrium may possibly be disrupted for some media. 相似文献
83.
Fast time spectral measurements of a gamma-ray burst acquired with a satellite-borne cooled germanium spectrometer during the 18 December, 1972 event indicate significant spectral variations during the course of the event. These data are compared with the results of other exerimenters providing additional evidence for spectral variations on short time scales. The fast time spectra are also compared with spectral measurements obtained by others with accumulation periods longer than typical time widths of the structure in the intensity profile and particularly with spectra averaged over the entire duration of the burst event.Paper presented at the COSPAR Symposium on Fast Transients in X- and Gamma-Rays, held at Varna, Bulgaria, 29–31 May, 1975. 相似文献
84.
Dr. S. Nakano 《Mineralogy and Petrology》1992,46(2):123-135
Summary The cooling history of the feldspars of a hypersthene-augite trachyte lava of Oki-Dogo island, Japan was investigated by optical microscope, electron microscope and X-ray microanalyzer. Anti-Rpakivi mantled feldspars in the alkaline volcanic rocks consist of anhedral plagioclase cores and subhedral to euhedral sanidine mantles. The interfaces between the cores and mantles are wavy, saw-tooth-like, or comb-like under the optical microscope, suggesting sanidine overgrowth after plagioclase was partially resorbed. Perthitic lenses or lamellae of plagioclase are also observed in the sanidine near the interfaces. After the formation of such mantled feldspars at the magmatic stage, perthitic lamellae were produced in sanidine due to subsolidus exsolution. Periodicity of the perthitic lamellae is below 10 nm.[/ab]
Zusammenfassung Die Abkühlungs-Geschichte von Feldspäten einer Hypersthen-Augit-Trachyt-Lava von der Insel Oki-Dogo, Japan, wurde mikroskopisch, elektronenmikroskopisch und mit der Mikrosonde untersucht. Anti-Rapakivi-Feldspate in den Alkali-Vulkaniten bestehen aus anidiomorphen Plagioklas-Kernen and idiomorphen Sanidin-Rändern. Die Grenzen zwischen Kernen and Randern erscheinen unter dem Mikroskop gewellt, sägezahnartig oder kammartig. Dies deutet darauf hin, daß Überwachsung mit Sanidin nach teilweiser Resorption von Plagioklas stattgefunden hat. Perthitische Linsen oder Lamellen von Plagioklas im Sanidin wurden im Grenzbereich der beiden Feldspäte beobachtet. Perthit-Lamellen im Sanidin entstanden durch Subsolidus-Entmischung nachdem die Feldspäte wahrend der magmatischen Phase gebildet worden waren. Die Periodizität der Perthit-Lamellen liegt unter 10 nm.相似文献
85.
The yearly variations of mean sea levels at various locations along the coasts of Japan have been investigated, based upon the data of observation taken at 55 tide-gauge stations from 1953 to 1970, and some discussions have been made on the relationships between those variations and meteorological and oceanographical conditions, etc. The results obtained are as follows:
- In cases covering 90% of all the tide-gauge stations, the magnitude of the annual mean rate of variation of ground level is less than 10 mm/year, and the mean value of the magnitude for all the stations is ?3.17 mm/year, while that exclusive of Osaka is ?1.7 mm/year.
- The effect of atmospheric pressure variation on the height of annual mean sea level is of the order of several centimeters in view from both time and place.
- In view of the characteristic types of variations, the coasts of Japan may be divided into five regions of similar mean sea level deviations. And in the yearly variations of mean sea levels, there can be seen a kind of variation which corresponds to the variation of oceanographical conditions such as abnormal fall of seawater temperature.
- The mean sea level deviations at various locations along the coasts of Japan, referred to the standard sea level “T.P.” are different for different places. Namely, (1) on the coast of the Japan Sea, the west coast of Kyushu, the coast of Sanriku and the coast of Hokkaido, the mean sea level is higher than on the Pacific coasts from Southern Kyushu to Southern Honshu. (2) Along the coast of the Seto-Inland Sea, the mean sea level is generally higher.
86.
Yugo Shimizu Takanori Iwao Ichiro Yasuda Shin-Ichi Ito Tomowo Watanabe Kazuyuki Uehara Nobuyuki Shikama Toshiya Nakano 《Journal of Oceanography》2004,60(2):453-462
Six newly developed floats, which were set to drift on the 26.7 σθ isopycnal surface and to profile temperature, salinity and pressure above 1000 dbar once a week, were deployed in the Oyashio
and Kuroshio Extension (KE) in order to examine the circulation, formation site and time scale of newly formed North Pacific
Intermediate Water (NPIW). The floats were deployed in February or May 2001, and the data from their deployments to December
2002 are analyzed here. Four of the six floats were deployed near the KE axis at around the first meander crest, and they
moved eastward to 157°E–176°W at latitudes of 30°N–45°N. The other two floats deployed in the Oyashio water with low-potential
vorticity near the south coast of Hokkaido moved southward to reach the KE front and then moved eastward to the same region
as the first four floats. The temperature and salinity at 26.7 σθ measured by the profiling floats indicate that the source waters of NPIW, Oyashio and Kuroshio waters are drastically mixed
and modified in the mixed water region west of 160°E. The floats were separated into the three paths east of 160°E between
the Kuroshio Extension front and the north of Water-Mass front (nearly subarctic front). New NPIW is judged to be formed along
these three paths since the vertical profiles of temperature and salinity are quite smooth, having a salinity minimum at about
26.7σθ along each path. Kuroshio-Oyashio isopycnal mixing ratios of the new NPIW are 7:3, 6:4 and 5:5 at 26.7σθ along the southern, middle and northern paths, respectively. Potential vorticity converges to about 14–15 × 10−11 m−1s−1 along these paths. The time scale of new NPIW formation is estimated to be 1–1.5 years from the merger of Oyashio and Kuroshio
waters to the formation of the new NPIW.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
87.
Yoshisuke Nakano 《Advances in water resources》1983,6(4):205-213
Similarity solutions to the second boundary value problem of unsaturated flow are studied in one-dimensional, semi-infinite porous media with the soil-water diffusivity proportional to some power of the water content. The existence and uniqueness of two types of similarity solutions to the problem are investigated and the properties of these solutions are presented. It is shown that these two types of similarity solutions exist and that they may not be unique for every parameter range studied. The use of the similarity solutions is discussed for the experimental determination of soil-water diffusivity. 相似文献
88.
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