大气环境中气体污染物空间浓度分布的重构

【作者】 王晓斐；

【导师】 王俊德； 李燕；

【作者基本信息】 南京理工大学 ， 应用化学， 2005， 硕士

【摘要】 本文利用遥感傅立叶变换红外光谱仪和计算机层析算法,对气体浓度在空间的分布进行重构。主要研究内容有以下三个方面: 1、利用曲线拟合算法对室内单光路上气体污染物浓度的分布进行了重构。通过对所用的六种拟合算法(5次、6次、7次、8次、9次最小二乘多项式拟合以及三次样条插值拟合)的比较,可知利用7次最小二乘多项式拟合所得到的重构结果与实际值最接近,优于其它算法。 2、利用双三次B样条曲面重构技术发展了一种快速算法,有效地重构出丙酮气体浓度在测量平面上的空间分布。将其重构出的浓度最大值及其位置的结果,与用SBFM算法得到的结果进行了比较,二者一致。该算法的一个突出特点是计算速度很快,仅0.719s,明显优于SBFM算法的计算速度(224s)。 3、本论文对丙酮、二氯甲烷、氯仿三种有机有毒大气污染物进行了气体浓度分布的快速重构。利用BP-ANN对混合气体的红外谱图进行解析,然后利用快速算法有效地重构出三种物质在测量平面上的浓度峰值和及其位置。更多还原

【Abstract】 This paper reconstructed distribution of gas concentration by Open-path FourierTransform Infrared Spectrometer in combination with Computed Tomography. The majorcontent was discussed as follows:1、 Curve fitting technique was applied into reconstructing gas concentration distribution along one beam path. Comparing the results from the six methods (5^th, 6^th, 7^th, 8^th and 9^th least-square polynomial curve fitting, and cubic-spline interpolation), it could be known that the 7^th least-square polynomial curve fitting performed better than others in the reconstruction results.2、 A rapid reconstruction algorithm was developed based on Bi-cubic B-spline surface technique. This algorithm could map gas concentration effectively in a two-dimensional plane. By comparison with SBFM algorithm, this rapid algorithm could get accordant results with SBFM algorithm about the reconstructed maximum concentration and its corresponding position. The most advantage of this rapid method lied in computing speed being just 0.719s, faster than the value of SBFM, which was 224s.3、 This paper also researched the performance of this rapid algorithm in reconstructing concentration distribution of acetone, methylene chloride, and chloroform in the measuring plane. BP-ANN technique was utilized to analyze the spectrogram of the mixed gas before reconstruction by this rapid algorithm. The results illustrated that this method worked well in the reconstruction of the maximum concentrations and its corresponding positions about the three VOCs.更多还原