Soil salinization may negatively affect microbial processes related to carbon dioxide （CO2） and nitrous oxide （N20） emissions. A short-term laboratory incubation experiment was conducted to investigate the effects...Soil salinization may negatively affect microbial processes related to carbon dioxide （CO2） and nitrous oxide （N20） emissions. A short-term laboratory incubation experiment was conducted to investigate the effects of soil electrical conductivity （EC） and moisture content on CO2 and N20 emissions from sulfate-based natural saline soils. Three separate 100-m long transects were established along the salinity gradient on a salt-affected agricultural field at Mooreton, North Dakota, USA. Surface soils were collected from four equally spaced sampling positions within each transect, at the depths of 0-15 and 15-30 cm. In the laboratory, artificial soil cores were formed combining soils from both the depths in each transect, and incubated at 60% and 90% water-filled pore space （WFPS） at 25 ~C. The measured depth-weighted EC of the saturated paste extract （ECe） across the sampling positions ranged from 0.43 to 4.65 dS m-1. Potential nitrogen （N） mineralization rate and CO2 emissions decreased with increasing soil ECe, but the relative decline in soil CO2 emissions with increasing ECe was smaller at 60% WFPS than at 90% WFPS. At 60% WFPS, soil N20 emissions decreased from 133 g N20-N kg-1 soil at ECe （ 0.50 dS m-1 to 72 μg N20-N kg-1 soil at ECe = 4.65 dS m-1. In contrast, at 90% WFPS, soil N20 emissions increased from 262 g N20-N kg-1 soil at ECe ： 0.81 dS m-1 to 849 g N20-N kg-1 soil at ECe ： 4.65 dS m-1, suggesting that N20 emissions were linked to both soil ECe and moisture content. Therefore, spatial variability in soil ECe and pattern of rainfall over the season need to be considered when up-scaling N20 and CO2 emissions from field to landscape scales.展开更多
应用X射线衍射(XRD)、扫描电子显微镜(能谱分析)(SEM-EDS)和电子探针显微分析等方法探讨了预涂覆碱金属硫酸盐的Co Cr Fe NiTi_(0.5)高熵合金在0.75%SO_2气氛中的腐蚀行为。结果表明:在0.75%SO_2气氛中,合金的腐蚀动力学曲线遵循"...应用X射线衍射(XRD)、扫描电子显微镜(能谱分析)(SEM-EDS)和电子探针显微分析等方法探讨了预涂覆碱金属硫酸盐的Co Cr Fe NiTi_(0.5)高熵合金在0.75%SO_2气氛中的腐蚀行为。结果表明:在0.75%SO_2气氛中,合金的腐蚀动力学曲线遵循"抛物线"规律;合金表面生成由Ti,Cr_2,Fe氧化物,尖晶石结构复杂氧化物AB_2O_4以及(Fe,Ni)硫化物组成的腐蚀产物;升高温度显著增加氧化膜厚度以及腐蚀影响区的孔隙密度,这使得氧化层与基体结合程度变差甚至剥离,腐蚀深度增大。Co Cr Fe Ni Ti_(0.5)高熵合金在含硫气氛下的腐蚀归因于腐蚀初期合金元素的氧化,以及随后发生的金属氧化物的硫酸盐化、三元共晶复合盐的形成以及合金元素Fe在熔盐中的溶解反应;不仅如此,介于合金基体与金属氧化层间的腐蚀影响区还发生了合金元素(Fe,Ni)的硫化。展开更多
文摘Soil salinization may negatively affect microbial processes related to carbon dioxide （CO2） and nitrous oxide （N20） emissions. A short-term laboratory incubation experiment was conducted to investigate the effects of soil electrical conductivity （EC） and moisture content on CO2 and N20 emissions from sulfate-based natural saline soils. Three separate 100-m long transects were established along the salinity gradient on a salt-affected agricultural field at Mooreton, North Dakota, USA. Surface soils were collected from four equally spaced sampling positions within each transect, at the depths of 0-15 and 15-30 cm. In the laboratory, artificial soil cores were formed combining soils from both the depths in each transect, and incubated at 60% and 90% water-filled pore space （WFPS） at 25 ~C. The measured depth-weighted EC of the saturated paste extract （ECe） across the sampling positions ranged from 0.43 to 4.65 dS m-1. Potential nitrogen （N） mineralization rate and CO2 emissions decreased with increasing soil ECe, but the relative decline in soil CO2 emissions with increasing ECe was smaller at 60% WFPS than at 90% WFPS. At 60% WFPS, soil N20 emissions decreased from 133 g N20-N kg-1 soil at ECe （ 0.50 dS m-1 to 72 μg N20-N kg-1 soil at ECe = 4.65 dS m-1. In contrast, at 90% WFPS, soil N20 emissions increased from 262 g N20-N kg-1 soil at ECe ： 0.81 dS m-1 to 849 g N20-N kg-1 soil at ECe ： 4.65 dS m-1, suggesting that N20 emissions were linked to both soil ECe and moisture content. Therefore, spatial variability in soil ECe and pattern of rainfall over the season need to be considered when up-scaling N20 and CO2 emissions from field to landscape scales.
文摘应用X射线衍射(XRD)、扫描电子显微镜(能谱分析)(SEM-EDS)和电子探针显微分析等方法探讨了预涂覆碱金属硫酸盐的Co Cr Fe NiTi_(0.5)高熵合金在0.75%SO_2气氛中的腐蚀行为。结果表明:在0.75%SO_2气氛中,合金的腐蚀动力学曲线遵循"抛物线"规律;合金表面生成由Ti,Cr_2,Fe氧化物,尖晶石结构复杂氧化物AB_2O_4以及(Fe,Ni)硫化物组成的腐蚀产物;升高温度显著增加氧化膜厚度以及腐蚀影响区的孔隙密度,这使得氧化层与基体结合程度变差甚至剥离,腐蚀深度增大。Co Cr Fe Ni Ti_(0.5)高熵合金在含硫气氛下的腐蚀归因于腐蚀初期合金元素的氧化,以及随后发生的金属氧化物的硫酸盐化、三元共晶复合盐的形成以及合金元素Fe在熔盐中的溶解反应;不仅如此,介于合金基体与金属氧化层间的腐蚀影响区还发生了合金元素(Fe,Ni)的硫化。
