摘要
采用气相色谱分离空气和甲烷是测定土壤脱附气中微量甲烷碳同位素δ13C整个实验的一个重要部分。此项分离,国外采用-70℃低温进样,我们由于设备条件所限,只能在20℃以上初温下注样。由计算得知,如果色谱分离的空气峰和甲烷峰保留时间间隔能保证在0.9分钟以上,就能使百分之百甲烷进入碳同位素测定的制样系统,为达此目的,必须选定可宜的色谱条件。
Abstract
Simplex method is a kind of mathematical optimum seeking method. It has been used to select optimum conditi ons of various experimental parameters.The author has applied the method to optimum seeking of experimental conditions for gas chromatography, such as flow rate of carrier gas, initial time, final column temperature, bridged eletric current, and the temperature of copper oxide oven.Through experiments and mathematical processes, five sets of conditions, i.e.Nos 12, 13, 15, 16, 17 points are considered to be the best. The basic idea of simplex method is to replace a worst point with a better one for the abrupt turn of a function.Thus, no matter how many dimensions a variable may has, only one experiment is needed for pushing one step to another.Besides, conditions selected by simplex method are gradually approaching optimum, and finally the graph will be oscilated within a certain range, which is the stable area near optimum conditions. So that multiple sets of conditions close to the optimum point can be chosen, and they are selective under different requirement.s Furthermore,because optimum point selected by simplex mehthod is obtained through comparision between experiments, there is no need for extra testing experiment.All these can not be achieved by other optimization method.
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