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Sun T.,Sichuan Normal University | Chen K.,The Second Research Institute of Civil Aviation Administration of China
Huaxue Gongcheng/Chemical Engineering (China) | Year: 2012

UV unit is one of the important operation units in the ultrapure water production. Due to high energy consumption of usual UV unit, searching a high-efficient energy-saving UV unit becomes one of the hottest research topics nowadays. The TiO2 film was successfully prepared by sol-gel method with tetrabutyl titanate as precursor and ethanol as solvent. The nitrogen-doped TiO2 film was attained by calcinations of TiO2 film through ammoniation at elevated temperature. The photocatalytic activities of synthesized catalysts were examined using ethylene glycol, isopropyl alcohol and urea as model organic contaminants in ultrapure water. The experimental results demonstrate that under the same ultraviolet light radiation, the catalytic effect of nitrogen-doped TiO2 is much better than that of TiO2, and the same oxidation effect can be achieved by either using 185 nm UV lamp only or using the combination of nitrogen-doped TiO2 with 254 nm UV lamp. The application of such technology in ultrapure water purification can greatly reduce the energy consumption and cost of production. Source

Peng W.,University of Electronic Science and Technology of China | Wang X.-G.,University of Electronic Science and Technology of China | Tang B.,University of Electronic Science and Technology of China | Wu H.-G.,The Second Research Institute of Civil Aviation Administration of China
Dianzi Yu Xinxi Xuebao/Journal of Electronics and Information Technology | Year: 2010

In this paper, based on the Dechirping technique, a new method of measuring relative delays among digital T/R modules for the wideband digital array utilizing wideband LFM pulses is proposed. To enhance radar system's flexibility and extensibility and reduce hardware costs, this method can be realized by software. By using the decimation and FFT algorithm, not only can the measurement method be easier to be implemented for computational efficiency and reduce data rate, but also good measurement precision and real-time performance are achieved, at the same time, all relative delays among multiple digital T/R modules are enabled to be acquired in one measurement process. The performance of the proposed method is analyzed from the theoretical angle and thus some optimal system parameters are determined. The simulation results show the effectiveness and efficiency of the proposed method. Source

Qiu R.,Southwest Jiaotong University | Zhu F.,Southwest Jiaotong University | Gou J.,Southwest Jiaotong University | Ye J.,The Second Research Institute of Civil Aviation Administration of China | Yang X.,The Second Research Institute of Civil Aviation Administration of China
Gaodianya Jishu/High Voltage Engineering | Year: 2015

In order to theoretically analyze and calculate induced current on cable caused by space electromagnetic field coupling, we obtained the analytic expression of the induced current for different terminal loads of cable by using the transmission line model with a distributed source of aerial shielded cable-ground circuit. Then we analyzed the resonance mechanism of induced current, and acquired the relationship between resonance frequency and cable's length. Additionally, we discussed the relationship among induced current resonance, ground conductivity, and cable's overhead height. The results show that, when resonance occurs in the induced current, its amplitude increases with the cables-ground circuit's time constant. Under preconditions including earth conductivity of 0.01 S/m, irradiation wave frequency of 75 MHz, cable radius of 4 mm, height between cable and ground of 1 m, cable length of 2 m, and both ends of cable being overhead, error between the theoretically calculated result and measured result of the cable induced current is below 5 dB. ©, 2015, Science Press. All right reserved. Source

Chen K.,University of Electronic Science and Technology of China | Zheng M.,University of Electronic Science and Technology of China | Liu W.,The Second Research Institute of Civil Aviation Administration of China | Wu H.,The Second Research Institute of Civil Aviation Administration of China
Dianbo Kexue Xuebao/Chinese Journal of Radio Science | Year: 2012

For the optimization of sparse separable array, a new method based on matrix pencil method is proposed to reduce the number of elements, to solve the element locations and to design the excitations. The pattern of seperable planar array is produced by the pattern of two orthogonal linear array. Firstly, the two desired orthogonal linear array radiation pattern is sampled to form a discrete data set. Secondly, a Hankel Matrix is built and the singular value decomposition (SVD) can be performed. By discarding the insignificant singular values, we obtain an optimal low-rank approximation of the Hankel matrix which corresponds to sparse antenna array. Finally, the generalized eigen-decomposition is employed to calculate the sparse linear array locations and excitations, then the locations and excitations of the sparse separable array are obtained. Simulation results are presented to demonstrate the efficiency of the proposed approach. Source

Chen K.,The Second Research Institute of Civil Aviation Administration of China | Sun T.,Sichuan Normal University | Xiang H.,The Second Research Institute of Civil Aviation Administration of China
Canadian Journal of Chemical Engineering | Year: 2016

Due to continued concern about effects of tetraethyl lead (TEL) emission on the environment and human health, the complete removal of TEL from aviation gasoline (avgas) is a desirable pursuit. In order to maintain high antiknock performance of avgas, an advanced adsorption method was developed using 5A zeolite to remove linear and monobranched alkane from avgas for octane number enhancement. An experimental study of single, binary, and quaternary adsorption of octane isomers on a fixed bed reactor was performed in this work. The effects of partial pressure, operating temperature, and initial mixture composition on breakthrough curves and sorption selectivity were thoroughly studied. At fixed partial pressure, normal octane was the strongest-adsorbed component, followed by 2-methylheptane, 2, 5-dimethylhexane, and 2, 2, 4-trimethylpentane. Adsorption capacity of all components increased with increased partial pressure and decreased with increased operating temperature. However, for all binary mixtures studied in this work, the sorption selectivity decreased as total pressure increased. At equimolar concentrations the normal and monobranched isomers were preferentially adsorbed, while when the volume percentages of the isomers were different, the adsorption of the isomer with the higher volume ratio was favoured. The quaternary breakthrough curves for octane isomers at 473K with each component having partial pressure of 0.15kPa also indicated the feasibility of simultaneous removal of normal and monobranched isomers from a multiple-component mixture by this 5A zeolite. © 2016 Canadian Society for Chemical Engineering. Source

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