A calculating spare parts supplied amount model based on marginal cost method is established and how to determine spare parts purchased amount based on limited support expenses is discussed.

Calculation and analysis of infiltration replenishment in river course;

In terms of groundwater flow, infiltration of rainwater, leakage releasing water and other aspects this paper analyzes the factors influencing the replenishment of deep groundwater resources in order to enhance the calculation accuracy to provide reasonable foundation for exploitation of groundwater.

Based on application of the theory of water balance,quantitative research on the water balance and the dynamical characteristics of monthly evaporation and replenishment of mobile sandy land in the growing season is conducted.

This paper deals with the essential principle and method of radioisotope (tritium) applied to hydrogeogeological surveing of railway tunnel, The tritium content is used to calculate the relative age judge vertical zoning of hydrogeological features of groundwater controled by structure,and then calcutation vertical seepage velocity of groundwater, determine the recharge rate of groundwater.