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31.
A technique for density measurement under high pressure and high temperature was developed using the X-ray absorption imaging method combined with an externally heated diamond anvil cell. The densities of solid and liquid In were measured in the pressure and temperature ranges of 3.2–18.6 GPa and 294–719 K. The densities obtained through the X-ray absorption imaging method were in good agreement (less than 2.0% difference) with those obtained through X-ray diffraction. Based on the measured density, the isothermal bulk modulus of solid In is determined as 48.0 ± 1.1?40.9 ± 0.8 GPa at 500 K, assuming K′ = 4 to 6. The compression curve of liquid In approaches that of solid In at higher pressures and does not cross over the solid compression curve in the measurement range. The present technique enables us to determine the densities of both solids and liquids precisely in a wide pressure and temperature range.  相似文献   
32.
A new method for wave propagation modeling is introduced in this paper. By using the constraint optimization (Lagrange multiplier) method, the sum of weighted squared Fourier amplitudes is minimized when subjected to a constraint. The sum of the maximum amplitudes obtained from all output models is normalized to unity and is taken as a constraint. In this method, all the actual time histories are considered as outputs and dealt with equally. Independently of the combinations of time histories (or the first ...  相似文献   
33.
A method has been developed for estimating the filtered narrow band surface albedo with Landsat/TM data. In this method, the surface albedo from filtered range of Landsat/TM is converted to the surface albedo with unfiltered spectral range. The atmospheric effects on each channel are systematically different, because of the different spectral behavior of atmospheric parameters. As a result, in this study, atmospheric correction has been done respectively in different parameters for visible and infrared channels. The surface albedos of the Kushiro Mire gotten with this method were compared with the observed data there. The results show that the satellite inferred albedos have a good agreement to the diurnal mean of ground observed albedos with 3% systematic error. There is a seasonal variation of albedo in high and low mires, the albedo decreased gradually from April to July and reached its minimum in July, further it rose gradually from August to October. It is also clear that there is a characteristic pattern of surface distribution according to the vegetation types of this area. The average surface albedos of each type of community are 0.164 for Sphagnum, 0.175 for Carex, 0.179 for Pragmites and 0.166 for Alnus. In the other words, the albedo in high mire (mainly covered by Sphagnum) is lower than that in low mire (mainly covered by Phragmites and Carex).  相似文献   
34.
In situ X-ray viscometry of the silicate melts was carried out at high pressure and at high temperature. The viscosity of the silicate melts in the diopside(Di)–jadeite(Jd) system was determined in the pressure range from 1.88 GPa to 7.9 GPa and in the temperature range from 2,003 K to 2,173 K. The viscosity of the Di 25%–Jd 75% melt decreases continuously to 5.0 GPa, whereas the viscosity of the Di 50%–Jd 50% melt increases over 3.5 GPa. The viscosity of the Di50%–Jd 50% melt reaches a minimum around 3.5 GPa. Since the amounts of silicon in the two melts are the same, the difference in the pressure dependence of the viscosity may be controlled by another network-forming element, i.e., aluminum. The difference in the pressure dependence of the viscosities in the melts with two intermediate compositions in the Di–Jd system is estimated to be due to the difference in the melt structures at high pressures and high temperatures.  相似文献   
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