Dielectric Properties of MWNTs/HDPE Composites in Terahertz Region Studied with Reverse Effective Medium Approach

2020 ◽  
Vol 42 (3) ◽  
pp. 358-358
Author(s):  
Wang Zhenqiang Wang Zhenqiang ◽  
Chen Xiliang Chen Xiliang ◽  
Liu Wei Liu Wei
Keyword(s):  
Refractive Index ◽  
Dielectric Properties ◽  
Absorption Coefficient ◽  
Time Domain ◽  
Effective Medium ◽  
Index Of Refraction ◽  
Terahertz Time Domain Spectroscopy ◽  
Terahertz Region ◽  
Effective Medium Approach ◽  
Properties Of Composites

Optical properties of composites MWNTs/HDPE were explored by terahertz time-domain spectroscopy (THz-TDS). It was found that with the increasing of frequency from 0.4 to 2 THz the absorption coefficient increases gradually whereas the refractive index decreases. Furthermore, composites with thick MWNTs possesses larger absorption coefficient and index of refraction compared to that with the thin MWNTs at the same concentration. The dielectric properties of the MWNTs were extracted with reverse effective medium approach (REMA) from that of the composites. The results of the absorption coefficient and refractive index for MWNTs calculated from different concentrations coincides well with each other. The extracted results were then analyzed with the Drude model combined with a localized Lorentz absorption.

scholarly journals Terahertz Time-Domain Polarimetry for Principal Optical Axes of Anisotropic Crystals

Photonics ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 213
Author(s):  
Alexander Mamrashev ◽  
Fedor Minakov ◽  
Nazar Nikolaev ◽  
Valery Antsygin
Keyword(s):  
Refractive Index ◽  
Absorption Coefficient ◽  
Time Domain ◽  
Detection System ◽  
Polarization Sensitivity ◽  
Practical Application ◽  
Terahertz Time Domain Spectroscopy ◽  
Lithium Triborate ◽  
Electro Optic ◽  
Optical Axes

We propose a method for measuring the terahertz properties for two principal optical axes of anisotropic crystals without optical activity using terahertz time-domain spectroscopy (THz-TDS). The method put forward in this paper utilizes the inherent polarization sensitivity of the THz-TDS electro-optic detection system. We demonstrate the practical application of the method by measuring the temperature dependence of the refractive index and the absorption coefficient of a lithium triborate crystal for three optical axes.

scholarly journals Terahertz Time Domain Spectroscopy to Detect Different Oxidation Levels of Diesel Engine Oil

Lubricants ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 18 ◽  
Author(s):  
Ali Abdul-Munaim ◽  
Jan Ornik ◽  
Martin Koch ◽  
Dennis Watson
Keyword(s):  
Refractive Index ◽  
Diesel Engine ◽  
Time Domain ◽  
Measurement Method ◽  
Oxidation Time ◽  
Engine Oil ◽  
Terahertz Time Domain Spectroscopy ◽  
Time Domain Spectroscopy ◽  
Thz Range

Diesel engine oil was subjected to thermal oxidization (TO) for six periods of time (0 h, 24 h, 48 h, 72 h, 96 h, and 120 h) and was subsequently characterized by terahertz time domain spectroscopy (THz-TDS). The THz refractive index generally increased with oxidation time. The measurement method illustrated the potential of THz-TDS when a fixed setup with a single cuvette is used. A future miniaturized setup installed in an engine would be an example of a fixed setup. For the refractive index, there were highly significant differences among the oxidation times across most of the 0.3–1.7 THz range.

Evaluating Oil Potential in Shale Formations Using Terahertz Time-Domain Spectroscopy

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Yizhang Li ◽  
Xinyang Miao ◽  
Honglei Zhan ◽  
Wei Wang ◽  
Rima Bao ◽  
...  
Keyword(s):  
Refractive Index ◽  
Time Domain ◽  
Oil Shale ◽  
Powdered Material ◽  
Specimen Preparation ◽  
Evolutionary Stage ◽  
Terahertz Time Domain Spectroscopy ◽  
Time Domain Spectroscopy ◽  
The Difference ◽  
Different Response

Optical assessment of oil shale using terahertz time-domain spectroscopy (THz-TDS) was carried out to study oil potential. Fischer assay testing was employed to obtain the oil yield of oil shale specimens to examine the difference of oil potential between oil shale samples from three regions: Beipiao, Barkol, and Huadian in China. Then, two types of specimens from each area were prepared for the optical tests and the results were compared. The refractive index (n) at 0.2–1.2 THz was derived; n decreased slowly with increasing frequency for all the specimens despite the oscillation pattern observed at lower frequencies. The specimen preparation method that mixed the powdered material led to minor differences between the specimens. The different response of kerogen to the terahertz pulse depending on the kerogen's evolutionary stage leads to a difference in the refractive index between the specimens from the various regions. This study indicates that using THz-TDS to evaluate the oil content in oil shale without inducing reaction within the specimen can be an effective method for resource exploration.

Accurate Complex Refractive Index with Standard Deviation of ZnTe Measured by Terahertz Time Domain Spectroscopy

2013 ◽  
Vol 52 (4R) ◽  
pp. 042401 ◽  
Author(s):  
Saroj R. Tripathi ◽  
Makoto Aoki ◽  
Masanori Takeda ◽  
Toshiaki Asahi ◽  
Iwao Hosako ◽  
...  
Keyword(s):  
Refractive Index ◽  
Standard Deviation ◽  
Time Domain ◽  
Complex Refractive Index ◽  
Terahertz Time Domain Spectroscopy ◽  
Time Domain Spectroscopy
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