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| | 講演要旨(英文) | | We used nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) technique to study pore microstructure. MRI experiment was carried out using spin-echo pulse sequence. In our experiment, brine of salinity 2% is subjected to cooling from the temperature of -3oC to -15oC. When brine undergoes freezing, only pure water converts into ice and salt remains in solution with increasing salinity of the solution. Unfrozen brine may be embedded inside micro pores in ice, with exhibiting solid-liquid co-existing system. Characterization of unfrozen brine was carried out with calculating T2 distribution. T1 weighted and diffusion weighted MR imaging technique were applied to obtained high resolution T1 weighted and DW-MR images of ice respectively. For the DW images, magnetic field gradient of 3mTm-1 was used. Two dimensional apparent diffusion coefficient (ADC) maps were prepared by DW images of b-value 0 and 81 s/mm2. MR images of partially frozen brine were prepared at temperatures of -3oC, -5oC, -7oC, and -12oC. We observed the spatial distribution of pores, microstructures and heterogeneity along the different direction of each sample slices at different temperatures. |
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