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292 results on '"Dang, Fei"'

4. Physical Properties of H II Regions in M51 from Spectroscopic Observations

Author

Wei, Peng, Zou, Hu, Kong, Xu, Zhou, Xu, Hu, Ning, Lin, Zesen, Mao, Yewei, Lin, Lin, Zhou, Zhimin, Liu, Xiang, Ma, Shuguo, Ma, Lu, Zhong, Tuhong, Dang, Fei, Sun, Jiantao, and Lin, Xinkui

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

M51 and NGC 5195 is an interacting system that can be explored in great details with ground-based telescopes. The H II regions in M51 were observed using the 2.16 m telescope of the National Astronomical Observatories of the Chinese Academy of Sciences and the 6.5 m Multiple Mirror Telescope with spatial resolution of less than $\sim100$ pc. We obtain a total of 113 spectra across the galaxy and combine the literature data of Croxall et al. to derive a series of physical properties, including the gas-phase extinction, stellar population age, star formation rate (SFR) surface density, and oxygen abundance. The spatial distributions and radial profiles of these properties are investigated in order to study the characteristics of M51 and the clues to the formation and evolution of this galaxy. M51 presents a mild radial extinction gradient. The lower gas-phase extinction in the north spiral arms compared to the south arms are possibly caused by the past encounters with the companion galaxy of NGC 5195. A number of H II regions have the stellar age between 50 and 500 Myr, consistent with the recent interaction history by simulations in the literatures. The SFR surface density presents a mild radial gradient, which is ubiquitous in spiral galaxies. There is a negative metallicity gradient of $-0.08$ dex $R_{e}^{-1}$ in the disk region, which is also commonly found in many spiral galaxies. It is supported by the "inside-out" scenario of galaxy formation. We find a positive abundance gradient of 0.26 dex $R_{e}^{-1}$ in the inner region. There are possible reasons causing the positive gradient, including the freezing of the chemical enrichment due to the star-forming quenching in the bulge and the gas infall and dilution due to the pseudobulge growth and/or galactic interaction., Comment: 20 pages, 8 figures, 1 appendix, Accepted for publication in PASP. Comments and suggestions are welcome

Published
2020
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11. The Adaptability Analysis of Hydrocyclone Separation for Sand and Natural Gas Hydrate to Back Pressure

Author

Wang, Dang-fei, Wang, Guo-rong, Zhong, Lin, Fang, Xing, di Prisco, Marco, Series Editor, Chen, Sheng-Hong, Series Editor, Vayas, Ioannis, Series Editor, Kumar Shukla, Sanjay, Series Editor, Sharma, Anuj, Series Editor, Kumar, Nagesh, Series Editor, Wang, Chien Ming, Series Editor, Sun, Baojiang, editor, Sun, Jinsheng, editor, Wang, Zhiyuan, editor, Chen, Litao, editor, and Chen, Meiping, editor

Published
2022
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15. Mechanics equilibrium in Tai-chi diagram.

Author

Dang, Fei, Xiao, Qingquan, and Yang, Pengfei

Subjects
*TAI chi, *YIN-yang, *POTENTIAL energy, *EQUILIBRIUM, *SIGNS & symbols
Abstract

Tai chi culture has a widespread influence on the world. Tai-chi diagrams, as the symbol of Tai chi culture, express the balance between Yin and Yang through the centrosymmetric pattern, but the balance connotation of Tai-chi diagrams needs a comprehensive understanding in more aspects, e.g., the balance in mechanics. In this work, we propose a mechanics theory to investigate the intrinsic mechanism of Yin–Yang equilibrium in ancient and modern Tai-chi diagrams. The model based on the minimum potential energy theory can effectively describe the interface curves of the Yin–Yang equilibrium by modifying boundary conditions, which is proven by experiments. The results show that the balance of Tai-chi diagrams is not only manifested in its symmetrical appearance but also reflected in its intrinsic balance configuration in mechanics. The model presented herein provides a new perspective to understand the balance of Tai-chi diagrams, which may provide useful insights into the applications of Tai-chi diagrams. [ABSTRACT FROM AUTHOR]

Published
2024
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18. Application of Automatic Mineral Analysis Technology to Identify Minerals and Occurrences of Elements in Sandstone-type Uranium Deposits in the Ordos Basin

Author

ZHANG Ran, YE Li-juan, DANG Fei-peng, XIAO Zhi-bin, BI Jun-hui, ZHOU Jing, GUO Hu, XU Ya-wen, GENG Jian-zhen, and ZHOU Hong-ying

Subjects
automatic mineral analysis system, energy dispersive spectrometer, sandstone type uranium deposit, mineral identification, occurrence of uranium minerals, ordos basin, Geology, QE1-996.5, Ecology, QH540-549.5
Abstract

BACKGROUND The Ordos Basin is one of the most important areas in China because it hosts lots of sandstone-type uranium deposits and a variety of other energy and mineral resources. The occurrence of uranium minerals is of great significance to the genetic understanding and prospecting of sandstone-type uranium deposits. However, the complex mineral composition, fine grain size, and various types and occurrences of uranium minerals make the initial identification stage of the study difficult. Currently, radiograph and electron probe microanalysis (EMPA) have played an important role in the identification of uranium minerals. Radiography can be used to obtain the position, occurrence and radioactive form of all uranium minerals in the light film at one time, but the mineral type cannot be identified. Moreover, it is a lengthy process and must be performed in darkness. Electron probe can be used to obtain the backscattered image of the uranium mineral. However, it takes time and effort to find uranium minerals with small content and small particle size in thin slices at high magnification, and it is impossible to quickly determine the types of associated minerals in BSE images. OBJECTIVES To find a more rapid and accurate method for identifying uranium minerals. METHODS The automatic mineral analysis system (AMICS), scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS) were used to identify minerals from sandstone-type uranium deposits in the north, south, and west margins of the Ordos Basin. RESULTS The minerals in the study were identified as coffinite, pitchblende, uraninite and uranophane. Pyrite and titanium oxide were closely related to uranium minerals, and other associated minerals were identified as quartz, rutile, feldspar, mica and kaolinite. CONCLUSIONS AMICS-SEM-EDS in situ analysis technology proves to be a reliable method for the rapid identification of uranium minerals, associated minerals, and their occurrences.

Published
2021
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29. Threats to Terrestrial Plants from Emerging Nanoplastics

Author

Dang, Fei, primary, Wang, Qingyu, additional, Yan, Xiliang, additional, Zhang, Yuanye, additional, Yan, Jiachen, additional, Zhong, Huan, additional, Zhou, Dongmei, additional, Luo, Yongming, additional, Zhu, Yong-Guan, additional, Xing, Baoshan, additional, and Wang, Yujun, additional

Published
2022
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30. KIC 3440495: A Rapidly Rotating δ Scuti-γ Doradus Hybrid Pulsator in a Binary System

Author

Ma, Shuguo, primary, Esamdin, Ali, additional, Hernández, Antonio García, additional, Murphy, Simon J., additional, Lv, Chenglong, additional, Wei, Peng, additional, Rieutord, Michel, additional, Pascual-Granado, Javier, additional, Dang, Fei, additional, Niu, Hubiao, additional, Yang, TaoZhi, additional, Feng, Guojie, additional, Karimov, Rivkat, additional, and Tillayev, Yusuf, additional

Published
2022
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47. Identification and Speciation of Nanoscale Silver in Complex Solid Matrices by Sequential Extraction Coupled with Inductively Coupled Plasma Optical Emission Spectrometry

Author

Hong, Aimei, primary, Tang, Qing, additional, Khan, Ashfeen Ubaid, additional, Miao, Maozhong, additional, Xu, Zhenlan, additional, Dang, Fei, additional, Liu, Qian, additional, Wang, Yawei, additional, Lin, Daohui, additional, Filser, Juliane, additional, and Li, Lingxiangyu, additional

Published
2021
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