Research of NO_(2) vertical profiles with look-up table method based on MAX-DOAS

Obtaining the vertical distribution profile of trace gas is of great significance for studying the diffusion procedure of air pollution.In this article,a look-up table method based on multi-axis differential optical absorption spectroscopy(MAX-DOAS)technology is established for retrieving the tropospheric NO_(2) vertical distribution profiles.This method retrieves the aerosol extinction profiles with minimum cost function.Then,the aerosol extinction profiles and the atmospheric radiation transfer model(RTM)are employed to establish the look-up table for retrieving the NO_(2) vertical column densities(VCDs)and profiles.The measured NO_(2) differential slant column densities(DSCDs)are compared with the NO_(2) DSCDs simulated by the atmospheric RTM,and the NO_(2) VCDs,the weight factor of NO_(2) in the boundary layer,and the boundary layer height are obtained by the minimization process.The look-up table is established to retrieve NO_(2) VCDs based on MAX-DOAS measurements in Huaibei area,and the results are compared with the data from Copernicus Atmospheric Monitoring Service(CAMS)model.It is found that there are nearly consistent and the correlation coefficient R2 is more than 0.86.The results show that this technology provides a more convenient and accurate retrieval method for the stereoscopic monitoring of atmospheric environment.

Automatic Measurement of LED Colorimetric Parameters Based on LabVIEW

In order to accurately and automatically measure the light emitting diode(LED) colorimetric parameters,the design of a measurement system by adopting a high-performance spectrometer and looking-up table method was presented based on the LabVIEW.First,the data of the LED relative spectral power distribution(SPD) were read by the spectrometer to measure LED chromaticity coordinate,and the slopes table were formed by the LED chromaticity coordinate and the equal stimulus point.Then,the CIE1931 chromaticity diagram was divided into 4 different regions to ensure the slopes table that had the character of monotonic decreasing.Finally,the LED dominant wavelength and purity were automatically calculated using the LabVIEW programs.The data of LEDs' colorimetric parameters have demonstrated that the measurement method in this paper can achieve higher precision result.

A Five-year Follow-up Study on the Efficacy and Safety of Female Tubal Sterilization by Chemical Instillation

A multi center randomized clinical trial was adopted in the present study. 1705 eligible women with identical demographic and gynecological characteristics were divided into two groups: 871 using phenol atabrine paste (PAP) and 834 using phenol mucilage (PM). The five year follow up rates for the two groups were 97.5% and 98.1%, respectively. The multiple decrement life table analysis showed that there was a significant difference in the gross cumulative failure rates between the two groups. The 60th month gross cumulative failure rates for PAP group and PM group were 4.61% and 11.87%, respectively, thus indicating the efficacy of PAP to be significantly higher than that of PM. 97.7% users had cervical smear examinations, but no suspected cancer cells or cancer cells were found. Meanwhile, there was no known diseases related to the chemical reagent. This follow up study indicates that tubal sterilization by chemical instillation is a simple,safe and efficient female method. It suggested that this method would be introduced to a wider use on the basis of modification in the composition of chemical agents, standardized operational procedure, and improved administrative regulation in the use of this technology.