45km
6.Ozone data observed by L625 differential absorption lidar in 2001 were processed and analyzed. Observation results show that ozone thickness is 0.264×10-5 km from 5 km to 45 km altitude over Hefei. Peak height is 24.9 km and peak value is 4.3677×1012 cm-3. Ozone number density at different altitude shows distinct seasonal characteristics.
8.This design requires P43 rail pinning up the line. The speed should be with 15km. However, actually, in the uphill sector when curve radius R= 500 and the gradient I= 1.2%, the speed should be no less than 45km, therefore, we should adopt the P36 steel I-beam in the carling construction instead of the P43 rail to connect and pin up the construction.
9.We studied geophysical data according to temperature pressure condition of gas hydrate and found that in seismic proifiles of some places in the northern margin of the South China Sea appear the Bottom Simulating Reflectors(BSR),and in other places the internal velocities of the first layer in sediments are 1 95～2 45 km/s,0 2～0 64km/s higher than those of general marine sediments.
