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Li Q.,China University of Petroleum - Beijing | Li Q.,Key Laboratory of Oil and Gas Terahertz Spectroscopy and Photoelectric Detection | Zhao K.,China University of Petroleum - Beijing | Zhao K.,Key Laboratory of Oil and Gas Terahertz Spectroscopy and Photoelectric Detection | And 5 more authors.
Science China: Physics, Mechanics and Astronomy | Year: 2014

The goal of continuous ambient participate monitoring has been accomplished by the use of terahertz (THz) wave. The frequency-dependent spectrum and absorbance of the particulate matter (PM2.5) were measured in the range of 0–10 THz. The PM2.5 concentration ρ was calculated according to the sampling time and air flow. With the increase of ρ, the THz wave amplitude gradually decreased and the absorbance A of PM2.5 increased. The relationship between r and A can be described mathematically through ρ ∝ A0.5. Our results demonstrate that the terahertz wave could be a valuable tool to monitor and inspect the PM2.5 concentration. © 2014, Science China Press and Springer-Verlag Berlin Heidelberg.


Leng W.-X.,China University of Petroleum - Beijing | Leng W.-X.,Key Laboratory of Oil and Gas Terahertz Spectroscopy and Photoelectric Detection | Ge L.-N.,China University of Petroleum - Beijing | Xu S.-S.,Polytechnic University of Mozambique | And 3 more authors.
Chinese Physics B | Year: 2014

Heptafluoropropane (HFP), as the best alternative to halon fire-suppression agents, is now a widely used fire extinguishing agent. The current studies of HFP, concentrating on the extinguishing mechanisms of flames and decomposition products, in general deal with the destructive and high temperature cases. In this paper, terahertz time-domain spectra are used to characterize HFP at different pressures. Optical parameters of HFP, such as absorption coefficient, refractive index, and relative permittivity, and their relationship with concentration of samples, are discussed. The absorption peak of HFP at 0.3 THz depends strongly on the applied pressure, and the corresponding parameters increase almost linearly with increasing HFP concentration. The present study lays a foundation for future extensive applications. © 2014 Chinese Physical Society and IOP Publishing Ltd.


Dong C.,China University of Petroleum - Beijing | Bao R.-M.,China University of Petroleum - Beijing | Zhao K.,China University of Petroleum - Beijing | Zhao K.,Key Laboratory of Oil and Gas Terahertz Spectroscopy and Photoelectric Detection | And 3 more authors.
Chinese Physics B | Year: 2014

The particle sizes and porosities of simulated pore structures are probed by terahertz time-domain spectroscopy. A double-peak time-domain spectrum phenomenon is observed when the terahertz (THz) pulses illuminated a pore and a particle. The amplitudes of the two peaks depend strongly and monotonically on the particle size and porosity. A model is used to study the phenomenon, and the computational results agreed with the experimental measurements. These measurements indicate the terahertz spectroscopic behaviors of pores and particles, suggesting that terahertz spectroscopy can be used as a noncontact probe of porosity. © 2014 Chinese Physical Society and IOP Publishing Ltd.


Ge L.N.,China University of Petroleum - Beijing | Zhan H.L.,China University of Petroleum - Beijing | Zhan H.L.,Key Laboratory of Oil and Gas Terahertz Spectroscopy and Photoelectric Detection | Leng W.X.,Key Laboratory of Oil and Gas Terahertz Spectroscopy and Photoelectric Detection | And 2 more authors.
Energy and Fuels | Year: 2015

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. © 2015 American Chemical Society.


Zhan H.,China University of Petroleum - Beijing | Wu S.,Sinopec | Bao R.,China University of Petroleum - Beijing | Bao R.,Key Laboratory of Oil and Gas Terahertz Spectroscopy and Photoelectric Detection | And 4 more authors.
Fuel | Year: 2015

The purpose of this article is to demonstrate the practicability to classify the sources and types of crude oils from different oil fields in several countries and regions with terahertz time-domain spectroscopy (THz-TDS). THz parameters spectra, such as refractive index and absorption coefficient, were calculated. Multivariate statistical methods, including cluster analysis (CA) and principal component analysis (PCA), were used to build models between THz parameters and crude oils from different countries and regions. The distances of CA between oils and the first principal component (PC1) scores of oils in PCA method reflected the oil-dependent differences, indicating that there existed consistency between CA and PCA. Consequently, the combination of THz technology as well as multivariate statistical methods could be an effective method for rapid identification of crude oils with different properties and geographical locations. © 2014 Elsevier Ltd. All rights reserved.


Qin F.,China University of Petroleum - Beijing | Qin F.,Key Laboratory of Oil and Gas Terahertz Spectroscopy and Photoelectric Detection | Li Q.,Key Laboratory of Oil and Gas Terahertz Spectroscopy and Photoelectric Detection | Zhan H.,Key Laboratory of Oil and Gas Terahertz Spectroscopy and Photoelectric Detection | And 4 more authors.
Science China: Physics, Mechanics and Astronomy | Year: 2014

Terahertz time-domain spectroscopy (THz-TDS) was used for the quantitative detection of sulfur content in gasoline. Models of chemo metrics methods and partial least squares (PLS) were built to measure THz-TDS and the sulfur content. All of the samples were divided into two parts. One part was used for calibration and the other one for validation. In order to evaluate the quality of the models, the correlation coefficient (R) and root-mean-square errors (RMSE) of calibration and validation models were calculated. The value of R and RMSE were close to 1 and 0 within acceptable levels, respectively, indicating that the combination of THz-TDS and PLS is a potential method for further quantitative detection. © 2014 Science China Press and Springer-Verlag Berlin Heidelberg.


Liu H.,China University of Geosciences | Sun Q.,China University of Petroleum - Beijing | Sun Q.,Key Laboratory of Oil and Gas Terahertz Spectroscopy and Photoelectric Detection | Xing J.,China University of Geosciences | And 6 more authors.
ACS Applied Materials and Interfaces | Year: 2015

In the present work, a ZnO nanowire array/reduced graphene oxide film hybrid nanostructure was realized, and the photovoltaic responses from the visible to the near-infrared range were investigated. Compared with the pure ZnO nanowire array and rGO thin film, the hybrid composite exhibited a fast and greatly enhanced broadband photovoltaic response that resulted from the formation of interfacial Schottky junctions between ZnO and rGO. © 2015 American Chemical Society.


Jin W.-J.,State Key Laboratory of Petroleum Resources and Prospecting | Jin W.-J.,China University of Petroleum - Beijing | Jin W.-J.,Key Laboratory of Oil and Gas Terahertz Spectroscopy and Photoelectric Detection | Zhao K.,State Key Laboratory of Petroleum Resources and Prospecting | And 6 more authors.
Applied Geophysics | Year: 2013

We measured the water content (0.01%-0.25% w/w) in crude oil emulsions using terahertz time-domain spectroscopy (THz-TDS). To improve the precision and range of the measurements, we used 1 and 10 mm thick quartz cells. The experiments were performed at 20 °C and the THz wave was transmitted vertically to the samples and detected on the other side. The experimental results suggest linear relation for the THz absorption coefficient and the water content of the crude oil emulsions in the observed range. The linear dependence facilitates high-precision measurements of the water content of crude oil. This suggests the potential of THz-TDS in determining the water concentration in crude oil and borehole fluid identification. © 2013 Editorial Office of Applied Geophysics and Springer-Verlag Berlin Heidelberg.


Jiang C.,China University of Petroleum - Beijing | Jiang C.,Key Laboratory of Oil and Gas Terahertz Spectroscopy and Photoelectric Detection | Zhao K.,China University of Petroleum - Beijing | Zhao K.,Key Laboratory of Oil and Gas Terahertz Spectroscopy and Photoelectric Detection | And 5 more authors.
Energy and Fuels | Year: 2014

Magnetic technology can significantly change the characteristics of crude oil, and the physical mechanism has received much attention for several years. To date, there is not yet an accurate conclusion. Terahertz time-domain spectroscopy is employed in this paper to characterize the optical parameters of selected wax-bearing crude oil under the action of a magnetic field. The corresponding absorption coefficient and extinction coefficient of samples are obtained by a fast Fourier transform frequency domain spectrum, and the aggregation characteristics of particles are analyzed in crude oil under a magnetic field. The decrease of the extinction coefficient may be suggested as qualitative proof of a magnetic-field-induced disaggregation of the suspended colloidal particles. Terahertz time-domain spectroscopy may be a powerful tool to characterize the particle disaggregation state in crude oil. © 2014 American Chemical Society.


Zhan H.,China University of Petroleum - Beijing | Zhan H.,Key Laboratory of Oil and Gas Terahertz Spectroscopy and Photoelectric Detection | Li Q.,China University of Petroleum - Beijing | Li Q.,Key Laboratory of Oil and Gas Terahertz Spectroscopy and Photoelectric Detection | And 7 more authors.
IEEE Transactions on Terahertz Science and Technology | Year: 2015

Economic and industrial development has led to increasing problems with particulate pollution in many countries. Particulate matter with the diameter of less than 2.5 \mum (PM2.5) is of concern in many cities. In this study, a total of 70 samples of PM2.5 were collected from dusty environments and analyzed using terahertz (THz) radiation. The transmission spectrum of PM2.5 had two distinct absorption bands between 2.5 and 7.5 THz. Their center frequencies were 3.36 and 6.91 THz, respectively. Based on the THz absorbance spectra, the elemental compositions were studied by monitoring PM2.5 masses in conjunction with two-dimensional correlation spectroscopy. Correlations between absorption bands and cross peaks in the synchronous and asynchronous plots indicated that the metallic oxides showed absorption features in the range from 2.5 to 7.5 THz. The vibration modes of anions and cations were located at relatively low and high frequencies, respectively. Statistical methods, including partial least squares and back propagation artificial neural network, were used to quantitatively characterize the PM2.5 content with the input of absorbance over the whole frequency range. This research indicates that THz spectral analysis of PM2.5 is a promising tool for investigating the composition and mass of pollutants. © 2011-2012 IEEE.

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Loading Key Laboratory of Oil and Gas Terahertz Spectroscopy and Photoelectric Detection collaborators