为了研究烟煤在太赫兹频段下的光谱特性规律,采用太赫兹时域光谱技术对国内7种烟煤进行了测试,获取了烟煤的吸收谱和折射率谱,并分析了不同烟煤中灰分,挥发分含量及其变质程度等因素对太赫兹光谱特性的影响。实验数据表明,当样本厚度为2 mm时,烟煤的有效频谱带宽为1.2~1.8 THz,在有效带宽内无明显吸收峰。随烟煤变质程度的增加,烟煤的吸收效应会逐渐减弱,其折射率会逐渐变小;随烟煤中灰分含量的增加,烟煤的吸收效应会逐渐增强,其折射率也逐渐变大。虽然烟煤在太赫兹频段的吸收特性和折射率差异是由烟煤中各种成分差异综合造成的,但研究结果表明烟煤的变质程度和灰分含量是影响其太赫兹频段物理特性的主要因素,通过太赫兹时域光谱技术可以实现多种烟煤的准确分类。

In order to study the spectrum characteristics of bituminous coal under terahertz frequency band,7 kinds of Chinese bituminous coal were tested by using terahertz time domain spectroscopy ( THz-TDS). The absorption spec- trum and refractive index spectrum of the 7 kinds of bituminous coal were obtained. The effects of ash content,volatile matter,metamorphism degree and other factors of different bituminous coals on terahertz spectrum characteristics were analyzed. The results show that when the thickness of sample is 2 mm,the effective spectral bandwidth of bituminous coal is 1. 2 ~ 1. 8 THz,and no obvious absorption peak has been found in the effective bandwidth. With the increase of bituminous coal metamorphism degree,the absorption effect of bituminous coal gradually decreases,and its refractive index becomes smaller. With the increase of ash content in bituminous coal,the absorption effect of bituminous coal gradually increases,and the refractive index becomes bigger. Although the absorption effect and refraction index differ- ence of different bituminous coals in terahertz band are synthetically caused by the difference in composition of bitumi- nous coal,the results show that the ash content and metamorphism degree of bituminous coal are the major factors af- fecting the spectral characteristics. The accurate classification of different bituminous coals can be achieved by using THz-TDS.