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Detection of CO Outflow in Rotating Cores

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Chinese Journal of Astronomy and Astrophysics 2008年第2期8卷 230-236页

作者： Xin Guan yue-fang wu Department of Astronomy Peking University Beijing 100871

We investigate the effect of bulk motion on the detection of molecular outflows in the sources S146, GGD27, and IRAS 22566＋5830. The traditional techniques do allow for bulk motions or systematic VLSR shifts of the core emissions, which may cause contamination of the high velocity gas emissions, and outflows may either fail to be detected or have their properties miscalculated. We used a program to follow the systematic shift of VLSR and better results have been obtained.

关键词： ISM: jets and outflows -- ISM: kinematics and dynamics -- ISM: molecules-- stars: formation

Molecular Cores in Different Evolutionary Stages near Luminous IRAS Sources and UC HII Regions

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Chinese Journal of Astronomy and Astrophysics 2007年第3期7卷 331-334页

作者： Lei Zhu yue-fang wu Department of Astronomy Peking University Beijing 100871

We report the results of ^12CO of Ultra-Compact （UC） HII regions with and ^13CO J=1-0 observations of eight candidates the Purple Mountain Observatory （PMO） Qinghai 13.7 -m telescope, which resulted in revealing 11 molecular cores. Their masses range from 130 to 1.7 × 10^4 M⊙, with different spatial scales （1 - 6 pc）. Also presented are the relevant HCO＋ j=1-0 maps, which enabled us to investigate more detailed structures of these cores. Further comparisons show that four of the cores deviated from the centers of infrared （MIR） emission of Midcourse Space Experiment （MSX）, while others correspond either to bright MIR sources or diffuse MIR background. This indicates various evolutionary phases of the cores, including quite early ones for those without MIR sources.

关键词： stars formation- ISM clouds- ISM molecules- ISM evolution

Infrared Characteristics of Associated Sources of Water Masers

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Chinese Journal of Astronomy and Astrophysics 2005年第6期5卷 587-594页

作者： Jarken Esimbek yue-fang wu Jun-Zhi Wang Department of Astronomy Peking University Beijing 100871 National Astronomical Observatories/Urumqi Observatory Chinese Academy of SciencesUrumqi 830011

We present an analysis of the infrared properties of 1417 water masers collected from the literature published by December 2004. The associated infrared sources of the water masers were identified with IRAS and MSX （Midcourse Space Experiment） catalogues. There are 1252 water masers associated with IRAS sources within 11, which include 700 interstellar and 552 stellar sources. For 382 sources, the IRAS counterpart identification and the maser classification are new. We found the colors of the interstellar maser sources are much redder than those of the stellar ones at IRAS wavelength bands; 99% of the interstellar maser sources are above black body line, while 95% of the stellar masers are below. The distribution difference of the two kinds of masers shown in the color-color diagram is due to their different optical depths and temperature distributions of dust regions. There are 743 water masers with MSX counterparts, of which 552 are interstellar masers and 191 are stellar masers. MSX colors of the associated sources of water masers are here analyzed for the first time. The color differences among the MSX bands are small and the interstellar masers are redder than the stellar masers. There is a correlation between the intensity of the stellar water maser emission and that of the 12μm and 25μm emissions, while there is no correlation between the water maser emission and the 8μm emission. The infrared intensity increases with increasing wavelength for the interstellar masers, while it is the opposite for stellar masers. These results may provide clues for the pumping of water maser and for the properties of the two kinds of maser emission regions.

关键词： masers - ISM kinematics and dynamics - stars mass loss

A search for massive young stellar objects with 98 CH_3OH maser sources

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Research in Astronomy and Astrophysics 2010年第1期10卷 67-82页

作者： Tie Liu yue-fang wu Ke Wang Department of Astronomy Peking University Beijing 100871 China

Using the 13.7 m telescope of the Purple Mountain Observatory （PMO）, a survey of the 3 = 1 - 0 lines of CO and its isotopes was carried out on 98 methanol maser sources in January 2008. Eighty-five sources have infrared counterparts within one arcmin. In the survey, except for 43 sources showing complex or multiple-peak profiles, almost all the ^13CO line profiles of the other 55 sources have large line widths of 4.5km s^-1 on average and are usually asymmetric. Fifty corresponding Infrared Astronomical Satellite （IRAS） sources of these 55 sources have Lbdl larger than 10^3 L⊙, which can be identified as possible high-mass young stellar sources. Statistics show that the ^13CO line widths correlate with the bolometric luminosity of the associated IRAS sources. Here, we also report the mapping results of two sources; IRAS 06117＋1350 and IRAS 07299-1651. Two cores were found in IRAS 06117＋1350 and one core was detected in IRAS 07299-1651. The northwest core in IRAS 06117＋1350 and the core in IRAS 07299-1651 can be identified as precursors of UC HII regions or high-mass protostellar objects （HMPOs）. The southeast core of IRAS 06117＋1350 has no infrared counterpart, seeming to be at a younger stage than the pre-UC HII phase.

关键词： stars formation -- ISM clouds -- ISM methanol maser

Gas infall in the massive star formation core G192.16–3.84

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Research in Astronomy and Astrophysics 2019年第3期19卷 71-78页

作者： Meng-Yao Tang Sheng-Li Qin Tie Liu yue-fang wu Department of Astronomy Yunnan University and Key Laboratory of Astroparticle Physics of Yunnan Province Korea Astronomy and Space Science Institute East Asian Observatory Department of Astronomy Peking University

Previous observations have revealed an accretion disk and outflow motion in the high-mass starforming region G192.16–3.84, but collapse has not been reported before. Here we present molecular line and continuum observations toward the massive core G192.16–3.84 with the Submillimeter Array. C18 O(2–1) and HCO+(3–2) lines show pronounced blue profiles, indicating gas infalling in this region. This is the first time that infall motion has been reported in the G192.16–3.84 core. Two-layer model fitting gives infall velocities of 2.0±0.2 and 2.8±0.1 km s-1. Assuming that the cloud core follows a power-law density profile(ρ∝ r1.5), the corresponding mass infall rates are(4.7±1.7)×10-3 and(6.6±2.1)×10-3 M⊙yr-1 for C18 O(2–1) and HCO+(3–2), respectively. The derived infall rates are in agreement with the turbulent core model and those in other high-mass star-forming regions, suggesting that high accretion rate is a general requirement for forming a massive star.

关键词： ISM individual objects(G192.16-3.84)-ISM molecules-stars formation

Design and Implementation of Nonlinear Precoding for MIMO-SDMA Toward 6G Wireless

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China Communications 2024年第1期21卷 69-87页

作者： Chaowu wu yue Xiao Shu fang Gang wu National Key Laboratory of Wireless Communications University of Electronic Science and Technology of ChinaChengdu 611731China

In this paper,we present a novel and robust nonlinear precoding(NLP)design and detection structure specifically tailored for multiple-input multipleoutput space division multiple access(MIMO-SDMA)systems toward 6G *** approach aims to effectively mitigate the impact of imperfect channel estimation by leveraging the channel fluctuation mean square error(MSE)for reconstructing a highly accurate precoding matrix at the ***,we introduce a simplified receiver structure that eliminates the need for equalization,resulting in reduced interference and notable enhancements in overall system *** conduct both computer simulations and experimental tests to validate the efficacy of our proposed *** results reveals that the proposed NLP scheme offers significant performance improvements,making it particularly well-suited for the forthcoming 6G wireless.

关键词： MIMO-SDMA nonlinear precoding Tomlinson-Harashima precoding(THP) vector perturbation(VP)

Superior compound coatings prepared by low-temperature vanadium-nitrocarburizing duplex treatment

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Rare Metals 2024年第4期43卷 1828-1835页

作者： Gen Jin fang-fang Xu Xun-Xun Hu yue Xu School of Chemistry Beihang UniversityBeijing100191China Guobiao(Beijing)Testing and Certification Co. LtdBeijing100088China School of Materials Science and Engineering Beihang UniversityBeijing100191China

Superior compound coatings were prepared on CK45 steel surface by vanadium-nitrocarburizing duplex treatment in low-temperature salt *** this study,the microhardness,the phase constitution and the compositional distribution in the coatings prepared under different conditions were systematically *** results indicated that the reactions among activated vanadium,carbon and nitrogen atoms occurred on the steel surface,leading to the formation of compound coatings composed of outermost and compound *** mechanism for the formation of compound layer as well as the growth kinetics of the layer was also *** the duplex treatment,the wear and corrosion resistances of steel surface were significantly *** was found that the growth kinetics of compound layer obeyed the parabolic law,with the activation energy of 122.82 kJ·moL^(-1).

关键词： Vanadium-nitrocarburizing duplex treatment Compound coatings Microstructure Formation mechanism Growth kinetics

Photocatalytic Activity Enhancement in Organic Dyes Degradation by Loading Ag Nanoparticles onto α-Fe_(2)O_(3)/ZnOs

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Journal of wuhan University of Technology(Materials Science) 2024年第2期39卷 309-314页

作者：李保六 MENG Xinrui yue Yifan GAO fang Key laboratory of Hubei Province for Coal Conversion and New Carbon Materials Wuhan University of Science and TechnologyWuhan 430081China

Fe_(2)O_(3)/ZnO/Ag ternary composite photocatalytic material was prepared by simple hydrothermal method,and its structure and photocatalytic properties were *** experimental results show that Fe_(2)O_(3)/ZnO/Ag exhibits better photocatalytic *** two hours of UV irradiation,the degradation rates of orange Ⅱ and methyl orange reached 91.9% and 75.9%,*** design and preparation of the photocatalyst provide a theoretical basis for the practical application of photocatalytic technology.

关键词： Fe_(2)O_(3) ZnO composites photocatalysis

Single thiolate replacement of metal nanoclusters

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Science China Chemistry 2024年第2期67卷 523-528页

作者： Ambreen Ambreen yue Zhou Wanmiao Gu Qing You Liang fang Guoqing Bian Nan Yan Nan Xia Zhikun wu Key Laboratory of Materials Physics Anhui Key Laboratory of Nanomaterials and NanotechnologyInstitute of Solid State PhysicsHefei Institutes of Physical Science(HFIPS)Chinese Academy of SciencesHefei230031China University of Science and Technology of China Hefei230601China Institute of Physical Science and Information Technology Anhui UniversityHefei230601China

Surface thiolates play important roles in evincing the structures and properties of thiolated metal nanoclusters—one type of recently emerging inorganic-organic hybrids,and thus the thiolate substitution,especially single thiolate substitution,is highly desirable for subtly tailoring the structures and properties of metal ***,such a single-thiolate substituting is challenging,and its influence on the metal-metal and metal-sulfur bonds remains mysterious due to the absence of the singlethiolate-substituted ***,we developed a combined method,concurrently synthesized the single-thiolate-substituted nanocluster and its parent nanocluster,and successfully resolved their structures by single crystal X-ray crystallography,which reveals that the single thiolate substitute has an obvious influence on the metal-metal and metal-sulfur bond lengths although it has no effect on the absorption ***,the metal-metal and metal-sulfur bonds show various thermal extensibility and even the negative thermal expansion phenomena of the Au–S bond were observed in the single-thiolate-substituted *** bond length-related stability was also ***,this study highlights a novel synthesis method and offers novel structural insights and an in-depth structure-property correlation of thiolated metal nanoclusters.

关键词： metal nanoclusters single thiolate replacement thermal expansion stability intercluster interaction