摘要
The terahertz （THz） time-domain spectroscopy technique was used to characterize the cooling process of solid n-alkanes. The THz waveforms of n-octadecane, n- nonadecane, n-eicosane, n-heneicosane, n-docosane, and n-pentacosane were obtained with the cooling time using the aforementioned noncontact optical method. The peak values of the THz signal were found to be related to the cooling temperature of n-alkanes. The THz wave was sensitive to the size and structure of particles in the liquid; therefore, the crystallization process of n-alkanes was monitored. An empirical equation based on signal attenuation was proposed to quantitatively distinguish the content change of structural order in the samples. Results present a new noncontact optical approach for characteriz- ing wax crystallization via THz time-domain spectroscopy.
The terahertz （THz） time-domain spectroscopy technique was used to characterize the cooling process of solid n-alkanes. The THz waveforms of n-octadecane, n- nonadecane, n-eicosane, n-heneicosane, n-docosane, and n-pentacosane were obtained with the cooling time using the aforementioned noncontact optical method. The peak values of the THz signal were found to be related to the cooling temperature of n-alkanes. The THz wave was sensitive to the size and structure of particles in the liquid; therefore, the crystallization process of n-alkanes was monitored. An empirical equation based on signal attenuation was proposed to quantitatively distinguish the content change of structural order in the samples. Results present a new noncontact optical approach for characteriz- ing wax crystallization via THz time-domain spectroscopy.
基金
This work was supported by the National Basic Research Program of China （No. 2014CB744302）, the Specially Funded Program on National Key Scientific Instruments and Equipment Develop- ment （No. 2012YQ140005）, the China Petroleum and Chemical Industry Association Science and Technology Guidance Program （No. 20160107）, and the National Natural Science Foundation of China （Grant No. 11574401）.
