To enhance the understanding about the utilization of steel slags as a cementitious material, we comparatively studied the chemical, mineralogical and morphological properties of two types of steel slag; basicoxygen-f...To enhance the understanding about the utilization of steel slags as a cementitious material, we comparatively studied the chemical, mineralogical and morphological properties of two types of steel slag; basicoxygen-furnace carbon slag(BOF C) and electric-arc-furnace stainless steel slag(EAF S). Moreover, we studied the standard consistency, setting time and the effect of the slag replacement ratios on the fluidity and compressive strength of blended cement mortar. The experimental results showed that BOF C had higher alkalinity, higher pH value and more hydraulic phases than EAF S. Both types of slag showed water reduction effect due to its high fineness. Neat BOF C paste showed flash set and acceleration in the initial setting time of blended cement especially at high slag proportions. However, EAF S prolonged the setting time of blended cement even at low slag proportions. The pH values for blended cement contained 50% BOF C or EAF S were lower than those of pure cement paste. Despite of slag type, compressive strength gradually decreased with increasing slags content. The strength of BOF C mortar was higher than that of EAF S mortar with the same replacement ratio for the same age. Slag activity index demonstrated that BOF C and EAF S conformed to the Chinese National Standard(GB/T 20491-2006) requirements for steel slag as grade one and grade two, respectively.展开更多
信噪比(signal to noise ratio,SNR)是评价传感器性能的重要参数,是衡量传感器所获取的数字信号真实性的重要指标。SNR的高低对遥感数据能否得到有效利用具有至关重要的作用。任何传感器的指标设置都要以满足用户需求为出发点,因此有必...信噪比(signal to noise ratio,SNR)是评价传感器性能的重要参数,是衡量传感器所获取的数字信号真实性的重要指标。SNR的高低对遥感数据能否得到有效利用具有至关重要的作用。任何传感器的指标设置都要以满足用户需求为出发点,因此有必要开展基于波谱模拟的红外成像仪SNR指标设置研究。首先运用已有地物波谱库数据,从数据模拟的角度出发,通过辐射传输模型,模拟得到入瞳辐亮度数据;然后生成并添加高斯白噪声,按照设计方给出的波谱响应函数进行波谱重采样,得到与设计传感器相同的波段;最后采用波谱特征拟合的方法,判别不同SNR条件下地物的可识别度。针对不同领域用户对地物识别的精度需求,给出相应的SNR建议,为传感器的设计提供科学合理的依据。展开更多
基金Funded by the National Natural Science Foundations of China(Nos.51378113 and 51438003)the Plan of Six Peak Talents in Jiangsu Province(No.JZ-004)Partly Supported by the National Basic Research Program of China(973 Program,No.2015CB655102)
文摘To enhance the understanding about the utilization of steel slags as a cementitious material, we comparatively studied the chemical, mineralogical and morphological properties of two types of steel slag; basicoxygen-furnace carbon slag(BOF C) and electric-arc-furnace stainless steel slag(EAF S). Moreover, we studied the standard consistency, setting time and the effect of the slag replacement ratios on the fluidity and compressive strength of blended cement mortar. The experimental results showed that BOF C had higher alkalinity, higher pH value and more hydraulic phases than EAF S. Both types of slag showed water reduction effect due to its high fineness. Neat BOF C paste showed flash set and acceleration in the initial setting time of blended cement especially at high slag proportions. However, EAF S prolonged the setting time of blended cement even at low slag proportions. The pH values for blended cement contained 50% BOF C or EAF S were lower than those of pure cement paste. Despite of slag type, compressive strength gradually decreased with increasing slags content. The strength of BOF C mortar was higher than that of EAF S mortar with the same replacement ratio for the same age. Slag activity index demonstrated that BOF C and EAF S conformed to the Chinese National Standard(GB/T 20491-2006) requirements for steel slag as grade one and grade two, respectively.
文摘信噪比(signal to noise ratio,SNR)是评价传感器性能的重要参数,是衡量传感器所获取的数字信号真实性的重要指标。SNR的高低对遥感数据能否得到有效利用具有至关重要的作用。任何传感器的指标设置都要以满足用户需求为出发点,因此有必要开展基于波谱模拟的红外成像仪SNR指标设置研究。首先运用已有地物波谱库数据,从数据模拟的角度出发,通过辐射传输模型,模拟得到入瞳辐亮度数据;然后生成并添加高斯白噪声,按照设计方给出的波谱响应函数进行波谱重采样,得到与设计传感器相同的波段;最后采用波谱特征拟合的方法,判别不同SNR条件下地物的可识别度。针对不同领域用户对地物识别的精度需求,给出相应的SNR建议,为传感器的设计提供科学合理的依据。
