By the comparison of the store technology of DAS,SAN,NAS,it introduces the multi-functional NAS structure,characteristic of memory technology,NAS present network,and the application and advantage in library.
This paper is centered on 51 serial MCU (AT89C52)and introduces with the corresponding circuit the functions of the electronic password lock to design, to store, to identify and to display codes and to drive the alarming circuit.
The five nutrient elements total storage in depth from 0 to 30 cm of the soil is 206 427.59 kg/hm~2, and available nutrient is 16 618.29 kg/hm~2, the crop nutrient elements storage amount just is occupying about 0.15% of the total nutrient store in the soil of five kind nutrient elements, and 1.95% of the available nutrient store in the soil of five kind nutrient elements.
Results The dose effect and time effect could be expressed by Y=95.4378D-91.2478 and Y=21.32T-3.96 respectively. The activity will decrease slightly with the rising of pH in pH conditions ranging from 5.5 to 8.5.Besides,the activity will not decrease after one year store or boiled at 100℃ for 2h.
The total store is 514.90 kg/hm~2 of the five kinds nutrient elements in the Robinia pseudoacacia forest ecosystem,and the tree layer nutrient element storage amount accouts for about 85.5 percent of total storage.