Soil samples were taken from depth of 0-12cm in the virgin broad- leaved/Korean pine mixed forest in Changbai Mountain in April, 2000. 20 μL·L-1 and 200 μL·L-1 CH4 and N2O concentration were supplied for a...Soil samples were taken from depth of 0-12cm in the virgin broad- leaved/Korean pine mixed forest in Changbai Mountain in April, 2000. 20 μL·L-1 and 200 μL·L-1 CH4 and N2O concentration were supplied for analysis. Laboratory study on CH4 oxidation and N2O emission in forest soil showed that fresh soil sample could oxidize atmospheric methane and product N2O. Air-dried soil sample could not oxidize atmospheric methane, but could produCt N2O. However, it could oxidize the supplied methane quickly when its concentration was higher than 20 μL·L-1. The oxidation rate of methane was increased with its initial concentration. An addition of water to dry soil caused large pulse of N2O emissions within 2 hours. There were curvilinear correlations between N2O emission and temperature (r2=0.706, p <0.05), and between N2O emission andtwater content (r2=0.2968. p <0.05). These suggested temperature and water content were important factors controlling N2O emission. The correlation between CH4 oxidization and temperature was also found while CH4 was supplied 200 μL·L-1 (r2 =0.3573, p<0.05). Temperature was an important f8Ctor controlling CH4 oxidation. However, when 20 μL·L-1 CH4 was supplied, there was no correlation among CH4 oxidization, N2O emission, temperature and water content.展开更多
为满足矿井变频通风系统对井下空气质量监测的需求,提出了一种基于改进随机森林的矿井空气质量评价方法,旨在精确监测矿井内部的空气质量,为变频通风系统推广应用提供重要参考,有效保障安全生产和矿工身体健康。首先,分析了矿井空气中...为满足矿井变频通风系统对井下空气质量监测的需求,提出了一种基于改进随机森林的矿井空气质量评价方法,旨在精确监测矿井内部的空气质量,为变频通风系统推广应用提供重要参考,有效保障安全生产和矿工身体健康。首先,分析了矿井空气中污染物来源及其对矿工健康的潜在危害,选取CO、SO_(2)、H_(2)S、NO_(2)和粉尘这5项主要污染物作为评价因子,建立了评价标准。其次,利用受试者工作特征(Receiver Operating Characteristic,ROC)曲线下的面积(Area Under Curve,AUC)改进随机森林算法,对矿井空气质量进行了综合评价。试验结果表明:模型性能较优,泛化误差最小值仅为0.0177,测试数据分类准确性最高达97.72%。基于改进算法开发的矿井空气质量评价系统,能够有效实现对矿井空气质量评价,具有较高的鲁棒性和准确性,为智慧矿山建设和矿井空气质量评价提供了新思路。展开更多
文摘Soil samples were taken from depth of 0-12cm in the virgin broad- leaved/Korean pine mixed forest in Changbai Mountain in April, 2000. 20 μL·L-1 and 200 μL·L-1 CH4 and N2O concentration were supplied for analysis. Laboratory study on CH4 oxidation and N2O emission in forest soil showed that fresh soil sample could oxidize atmospheric methane and product N2O. Air-dried soil sample could not oxidize atmospheric methane, but could produCt N2O. However, it could oxidize the supplied methane quickly when its concentration was higher than 20 μL·L-1. The oxidation rate of methane was increased with its initial concentration. An addition of water to dry soil caused large pulse of N2O emissions within 2 hours. There were curvilinear correlations between N2O emission and temperature (r2=0.706, p <0.05), and between N2O emission andtwater content (r2=0.2968. p <0.05). These suggested temperature and water content were important factors controlling N2O emission. The correlation between CH4 oxidization and temperature was also found while CH4 was supplied 200 μL·L-1 (r2 =0.3573, p<0.05). Temperature was an important f8Ctor controlling CH4 oxidation. However, when 20 μL·L-1 CH4 was supplied, there was no correlation among CH4 oxidization, N2O emission, temperature and water content.
文摘为满足矿井变频通风系统对井下空气质量监测的需求,提出了一种基于改进随机森林的矿井空气质量评价方法,旨在精确监测矿井内部的空气质量,为变频通风系统推广应用提供重要参考,有效保障安全生产和矿工身体健康。首先,分析了矿井空气中污染物来源及其对矿工健康的潜在危害,选取CO、SO_(2)、H_(2)S、NO_(2)和粉尘这5项主要污染物作为评价因子,建立了评价标准。其次,利用受试者工作特征(Receiver Operating Characteristic,ROC)曲线下的面积(Area Under Curve,AUC)改进随机森林算法,对矿井空气质量进行了综合评价。试验结果表明:模型性能较优,泛化误差最小值仅为0.0177,测试数据分类准确性最高达97.72%。基于改进算法开发的矿井空气质量评价系统,能够有效实现对矿井空气质量评价,具有较高的鲁棒性和准确性,为智慧矿山建设和矿井空气质量评价提供了新思路。
