Abstract. Four varieties of Chinese milled rice samples with 11.90-15.56% initial moisture content (IMC, wet basis) were used to determine the rate of moisture adsorption using the gravimetric method at 10, 20, 25, 30, and 35°C under 65%, 86%, and 100% relative humidity (RH), respectively. A moisture diffusion equation was modified to fit the relationship between the moisture ratio (MR) of samples and exposure time. In the range of 65% to 100% RH, the lower IMC of milled rice samples corresponded to higher moisture adsorption rate at temperatures of 10 to 35°C. The moisture adsorption rate of samples increased with an increasing temperature. The moisture sorption rate of samples with the same IMC increased with increasing RH at certain temperatures. A single milled rice kernel was geometrically considered a finite homogeneous cylinder shape, and the analytical solution of the partial differential equation of moisture diffusion was given. The effective moisture diffusivity was calculated using a slope method by plotting the experimental data in terms of ln (MR) versus rewetting time. In the range of 10-35°C, the effective moisture adsorption diffusivity of milled rice kernels with normal moisture was 4.321×10 -9 -1.117×10 -7 m 2 h -1 . For the same IMC, the effective moisture diffusivity of milled kernels tended to increase with increases in surrounding temperature at certain relative humidity levels, but decreased with an increase in RH at certain temperatures. It was concluded that the milled rice samples from different types had similar effective moisture diffusivity when similar IMC was given.

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-In stored-grain bulk, its state would be affected by the coupling actions of temperature, humidity, moisture, gas and so on. However the most important factors are temperature and humidity. In the paper, the wheat was sealed in the 30 ℃ temperature difference simulation bin for about 75d. The results indicated that the fastest of the temperature change rate was the upper of grain bulk in the same vertical direction of the same plane. In the same way, the grain with nearer to the high temperature district was faster temperature rise and higher amplitude. To the relative humidity of grain bulk, the change of the close to higher temperature grain zone was fiercer than the others. And the relative humidity of low temperature area would change gently. The micro-airflow in grain mainly stemmed from the temperature differences. So the migration and redistribution of the temperature and relative humidity in wheat bulk was caused by the actions of conduction and convection. And the convection was the predominant action in grain bulk. In addition, the differences between heat and mass transfer in vertical and horizontal direction could demonstrate that the grain is anisotropy.