Oil yield is an important indicator for oil shale to optimize the comprehensive utilization. Generally, oil shale is highly anisotropic owing to the combined effects similar to shale. In this paper, THz-TDS was employed to investigate the anisotropic response of oil shale samples from Longkou, Yaojie, and Barkol with different oil yields. All the samples had significant anisotropy of the refractive index (n) and absorption coefficient (α) with symmetries at a location of 180°, which corresponded with the bedding plane and the partial alignment of particles. Additionally, the D values of experiment n in the vertical and parallel directions of the bedding plane were calculated as Δn′ = n ⊥ − n ∥ , and samples from Beipiao and Huadian were also tested in the horizontal and vertical directions for a sufficient number of THz parameters. Linear regression was built between the Δn′ of the samples from five regions and the oil yield, described as y = 60.86x+3.72 for oil yield (y) and Δn′ (x), with the correlation coefficient R equaling 0.9866, and the residual sum of squares was 1.182, indicating THz technology could be an effective selection for evaluating the oil yield of oil shale.

High-water-cut crude oil is currently the main form of underground oil in China. The high water content and the distribution of oil and water have an important impact on the rheological property and exploration efficiency. Terahertz (THz) waves are extremely sensitive to hydrogen bonds and intermolecular forces, and consequently, the responses of oil, water and air exhibit obvious differences. In this work, a series of crude oils with high water content were investigated by using THz timedomain spectroscopy (THz-TDS). Linear models were built between amplitudes of THz-TDS and the absorbance and water content from 50.05% to 100.00% with correlation coefficients (R) of 0.99 and >0.93, respectively. In addition, oil and water were determined to be distributed at different positions, based on THz signals in a series of oriented scans. Moreover, the transparent parts for visible light are identified by scanning the local points. The positions with low and high THz intensities refer to water and air regions, respectively. Therefore, THz technology is expected to act as a supplementary method to characterize highwater-cut crude oil, which will promote the efficiency and safe operation of pumping units and oil pipelines.

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A rapid technique is necessary to detect the natural gas which is a more and more significant fuel resource in modern industry. Terahertz (THz) technique was employed in this research to detect the principal hydrocarbon components of natural gas including methane, ethane, and propane. Two- and three-component mixtures were measured by THz setup, respectively. The amplitude ratio and time delay deviation of THz peaks between samples and reference were calculated. Phase projection pictures were obtained between the component concentrations and the amplitude ratio as well as time deviation. The phase figures evidently reflected the concentration dependent THz response, and a greatly different distribution was located in the whole phase projection area. In addition, back-propagation artificial neural networks method was utilized for the quantitative determination of components concentration and total pressure, and the correlation coefficient of the prediction set was proved to be 0.9859. Therefore, THz technique can satisfy the increasing need of rapid and efficient detection in the natural gas industry.

The current study surveyed major studies on the characteristics of motivating factors for knowledge workers, both in the USA and in China. Comparisons were made between studies in the two countries, and new perspectives were offered on the motivating factors for knowledge workers. Future research directions were proposed.