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394 results on '"Shi, Zhijun"'

11. Experimental study on the performance of micro gas turbines under different intake environments

Author

Liu Cong, Shi Zhijun, Li Yimin, Zhou Zhongning, and Ma Lina

Subjects
Micro gas turbine, Combustion characteristics, Pollutant emissions, NOx concentration, Intake environments, Experimental study, Engineering (General). Civil engineering (General), TA1-2040
Abstract

This article uses experimental methods to measure the operational performance and pollutant emissions of micro gas turbines in different intake environments, and analyzes the feasibility of replacing mine ventilation fans with micro gas turbines. The results show that when the compressor efficiency is increased from 70 % to 90 %, the total efficiency of the micro combustion engine is increased from 28% to 34 %, with an increase of up to 21.4 %. When the demand power is 25 kW, the fluctuation range of NOx emission concentration is within 5.4 %. When the intake opening is below 50 %, the effect is obvious. When the intake opening is reduced from 50 % to 25 %, the performance of the micro gas turbine decreases by 0.7 %; The influence of intake humidity on various operating parameters of micro gas turbines is generally within 3 %, which can meet the requirements of high humidity environment operation; The intake temperature has the greatest impact, with an increase in intake temperature leading to a decrease in power generation efficiency. After comprehensive analysis, we believe that the application of gas turbines in mines is feasible.

Published
2024
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30. Bright colloidal gallium-doped CuInS2 quantum dots for luminescent solar concentrators.

Author

Chen, Haoran, Xu, Zhipeng, Shi, Zhijun, Zhao, Fenghuan, Cao, Lixin, Dong, Bohua, and Xia, Chenghui

Abstract

We have developed an efficient strategy to improve the brightness and stability of CuInS2 quantum dots via Ga3+ doping combined with the overgrowth of a ZnS shell. The incorporation of Ga3+ into crystal lattices greatly suppresses the diffusion of Cu+ and reduces the formation of Cu-related defects, leading to a photoluminescence quantum yield as high as 92%. These nanocrystals can be integrated into luminescent solar concentrators and the devices exhibit a power conversion efficiency reaching 3.87%. [ABSTRACT FROM AUTHOR]

Published
2024
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44. Photothermal Oxidation of Cyclohexane Over CeO2/g-C3N4 Composite with S-Scheme Heterojunction in Solvent-Free Conditions.

Author

Ding, Fangruo, Wang, Ya, Shi, Zhijun, Gao, Changsheng, Kan, Mei, Liang, Qianli, Gao, Zheng, Li, Shiqing, Peng, Rusi, Ma, Ying, Shangguan, Wenchao, Meng, Sugang, and Chen, Shifu

Abstract

The selective oxidation of saturated C-H bonds has long been a significant challenge in chemical research, with the partial oxidation of cyclohexane (Cy) to KA oil (a mixture of cyclohexanol and cyclohexanone) using molecular oxygen (O2) recognized as one of the most important reactions. In this study, we demonstrate the selective oxidation of cyclohexane via photothermal synergism under solvent-free conditions and in the presence of a co-catalyst system. We have elucidated the synergistic effect of the CeO2/g-C3N4 composite catalyst in the photothermal oxidation of cyclohexane. The CeO2/g-C3N4 composite achieved a cyclohexane conversion of 13% and a KA oil selectivity of 97.5%, surpassing the simple additive effects of photocatalysis and thermal catalysis. Through extensive characterization techniques, we present a detailed mechanistic study. Photo-generated electron–hole pairs facilitate the valence cycling of metals during thermal processes, while heat promotes the efficient utilization of these carriers. Furthermore, lattice oxygen can trap holes, reducing the recombination probability of photo-generated charge carriers. This interaction results in a synergistic effect between light and heat, elucidating the phenomenon of photothermal cooperative catalysis in the composite catalyst. These findings suggest that photothermal co-catalysis holds considerable potential for widespread application in green industrial catalytic processes, offering high selectivity and efficiency in organic transformations. Herein, we synthesized a CeO2/g−C3N4 composite with S−scheme heterojunction as a photothermal catalyst, and employed it for the oxidation of Cy to K−A oil in a solvent−free system. CeO2 demonstrates prominent photothermal synergy, and the addition of g−C3N4 can enhance the utilization of electron–hole pairs. This method significantly improves cyclohexane conversion and KA oil selectivity and exceeds the sum of generations of pure photocatalysis and thermal catalysis. The results provide a mechanistic description for photothermal co−catalysis and demonstrate its potential for widespread use in green industrial catalysis [ABSTRACT FROM AUTHOR]

Published
2025
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