Biomedical subjects

Kai-Fa Cao

Publications and source records attributed to Kai-Fa Cao.

2 recordsLinked to original sources

PubMed2006

[Study on the nonlinear Raman lidar monitoring the CO2 gas].

It is a new skill to use SRS rays as emitting waves for the lidar monitoring CO2 gas, and the nonlinear Raman lidar based on the SRS process was devised. The third harmonic Nd: YAG laser wave (354.7 nm) was injected into the Raman cells filled with higher pressure gases, CO2 and N2. The first Stokes (S1) line 371.66 nm (CO2) and 386.7 nm (N2) were generated by stimulated Raman scattering. The variable S1 energy was measured by changing the gas pressure in the Raman cell andthe Nd:YAG laser system output energy. The optimum pressures of the CO2 and N2 in the Raman cell were achieved. Moreover, the principles of this physical process were put forward. This skill has been applied to the lidar for monitoring the CO2 gas.

English Abstract↗

PubMed2006

[Method for retrieving pollution gas concentration from Raman lidar return].

Raman lidar is an important tool for the detection of atmosphere pollution, and inversion for lidar returns is an important process. The key for inversion is to get transmission exponential function exp [integral of 0 (R) [alpha(lambda1, z) - alpha(lambda2, z)]]. Three methods with extinction coefficient as the center are presented. First, 532 nm atmospheric extinction coefficient was used to indirectly obtain alpha(lambda1, z) and alpha(lambda2, z). This method has been used generally by people. Two new methods were proposed: 1, reference gas with approximate Raman wavelength is used so that alpha(lambda1, z) = alpha(lambda2, z). 2, Mie-Rayleigh scattered return with wavelength lambda1 or lambda2 is used to compute exp [integral of 0 (R) [alpha(lambda1, z) - alpha(lambda2, z)]].

English Abstract↗