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CCD Photometry of Asteroid (147) Protogeneia

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Chinese Journal of Astronomy and Astrophysics 2006年第6期6卷 729-732页

作者： xi-liang zhang xiao-Bin Wang Li-Yun zhang National Astronomical Observatories / Yunnan Observatory Chinese Academy of Sciences Kunming 650011 Graduate School of Chinese Academy of Sciences Beijing 100049

We measured the light-curve of the asteroid （147） Protogeneia in November 2004, with a CCD detector attached to the 1-meter telescope at the Yunnan Observatory, China. The synodic period and maximum amplitude of （147） at this apparition are 7.852 hours and 0.25 mag, respectively. The value of a/b for （147）, from a preliminary estimation, is not less than 1.26：1.

关键词： asteroid - photometric observation - synodic period

Exploring U.S.-China climate cooperation through linked carbon markets

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Advances in Climate Change Research 2023年第1期14卷 145-155页

作者： Alexander F.LI Chen-Fei QU xi-liang zhang Schwarzman College Tsinghua UniversityBeijing 100084China Institute of Energy Environmentand EconomyTsinghua UniversityBeijing 100084China

Emissions trading systems(ETSs)are a widely used policy tool for driving emissions reductions and serve as an avenue for international climate *** the recent global agreement on carbon market standards at COP26,this study explores linked ETSs as an avenue for the *** China to cooperate on climate *** emissions,energy,and economic effects of linked ETSs are analyzed through the China-in-Global Energy Model(C-GEM),a multi-regional,computable general equilibrium *** the development of national economy-wide ETSs,two scenarios are developed linking China and the U.S.:1)a bilateral U.S.-China ETS linkage 2)a multilateral ETS linkage that includes China,the U.S.,and nations in Southeast *** indicate that emissions and energy consumption outcomes would be similar in the bilateral and multilateral ***,economic outcomes are more favorable in the multilateral linkage *** China and the *** in bilateral ETS linkage,China predominantly benefits from additional support for domestic decarbonization while the *** from increased GDP compared to without ETS *** Southeast Asia to establish multilateral linkage improves GDP outcomes for all participants,reducing adverse effects on China's GDP while boosting GDP for the *** Southeast *** policymakers considering the design and implementation of international ETSs,this study presents updated modeling on the effects of ETS linkage on each country as well as the economic benefits of expanding participation to additional regions.

关键词： U.S.-China climate cooperation Climate change Emissions trading system Carbon markets Computable general equilibrium model

A novel hybrid algorithm for lucky imaging

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Research in Astronomy and Astrophysics 2021年第5期21卷 155-167页

作者： Jin-liang Wang Bin-Hua Li xi-liang zhang Faculty of information engineering and automation Kunming University of Science and TechnologyKunming 650500China Key Laboratory of Applications of Computer Technologies of the Yunnan Province Kunming University of Science and TechnologyKunming 650500China Yunnan Observatories Chinese Academy of SciencesKunming 650011China

Lucky imaging is a high-resolution astronomical image recovery technique with two classic implementation algorithms,*** selecting,shifting and adding in image space,and data selecting and image synthesizing in Fourier *** paper proposes a novel lucky imaging algorithm where with space-domain and frequency-domain selection rates as a link,the two classic algorithms are combined successfully,making each algorithm a proper subset of the novel hybrid *** results show that with the same experiment dataset and platform,the high-resolution image obtained by the proposed algorithm is superior to that obtained by the two classic *** paper also proposes a new lucky image selection and storage scheme,which can greatly save computer memory and enable lucky imaging algorithm to be implemented in a common desktop or laptop with small memory and to process astronomical images with more frames and larger *** addition,through simulation analysis,this paper discusses the binary star detection limits of the novel lucky imaging algorithm and traditional ones under different atmospheric conditions.

关键词： methods:data analysis techniques:high angular resolution techniques:image processing

Development of low-carbon technologies in China's integrated hydrogen supply and power system

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Advances in Climate Change Research 2024年第5期15卷 936-947页

作者： Dai-Wei LI un-Ling HUANG Dan YU Da zhang xi-liang zhang Tsinghua University-China Three Gorges Corporation Joint Research Center for Climate Governance Mechanism and Green Low-carbon Transformation Strategy Beijing 100084China Institutes of Energy Environment and EconomyTsinghua UniversityBeijing 100084China International Clean Energy Research Office China Three Gorges CorporationBeijing 100038China National Center for Climate Change Strategy and International Cooperation Bejing 100035China

Hydrogen and electricity are crucial and interdependent energy carriers in China's pursuit of carbon neutrality,suggesting the necessity of utilizing cost-effective low-carbon technologies that facilitate their integrated *** cost-optimal,provincial level,deployment of low-carbon technologies under this long-term goal remains to be *** study employs the REPO model to identify the cost-optimal,low-carbon hydrogen production mixes and the evolution of the integrated power system of China from 2020 to *** integrated planning and operation of hydrogen supply and power systems are explored at the provincial *** role of high-temperature gas-cooled reactors in this integrated energy system is also *** results reveal that electrolytic hydrogen would dominate China's hydrogen supply after 2040,with alkaline,proton exchange membrane,and solid oxide electrolyzers produce over 1 Mt of hydrogen in the short term,by 2035,and in *** the low-carbon heat production of high-temperature gas-cooled reactors in addition to its electricity generation to meet the thermal requirements of solid oxide electrolyzers could boost the output to 4.2 Mt in 2050 and reducing the total system CO_(2) emissions and costs by 2.28%and 0.05%,*** 2050,the integration of hydrogen supply and power systems also generates up to 2194 TW h of flexible electricity demand by electrolyzers,which raised the renewable energy penetration by 4 percentage points while decreasing the need of flexible natural gas power generations and energy *** study is valuable for proposing the analytical framework and performing the provincial-level study of decarbonization of China's integrated hydrogen supply and power system.

关键词： Hydrogen energy Power system Energy system modelling Scenario analysis Carbon neutrality

Discovery of extended structures around two evolved planetary nebulae M2–55 and Abell 2

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Research in Astronomy and Astrophysics 2020年第7期20卷 149-160页

作者： Chih-Hao Hsia Yong zhang xi-liang zhang Tao Luo State Key Laboratory of Lunar and Planetary Sciences Macao University of Science and TechnologyTaipaMacaoChina School of Physics and Astronomy Sun Yat-Sen University Zhuhai CampusTangjiaZhuhai 519082China Yunnan Observatories Chinese Academy of SciencesKunming 650216China

We report a multi-wavelength study of two evolved planetary nebulae(PNs)M 2–55 and Abell *** optical narrow-band images([O III],Hα,and[N II])of M 2–55 reveal two pairs of bipolar lobes and a new faint arc-like *** arc-shaped filament around M 2–55 appears as a well-defined boundary from southwest to southeast,strongly suggesting that this nebula is in interaction with its surrounding interstellar *** the imaging data of Wide-field Infrared Survey Explorer(WISE)all-sky survey,we discovered extensive mid-infrared halos around these PNs,which are approximately twice the size of their main nebulae seen in the *** also present a mid-resolution optical spectrum of M 2–55,which shows that it is a high-excitation evolved PN with a low electron density of 250 cm^-***,we investigate the properties of these nebulae from their spectral energy distributions(SEDs)by means of archival data.

关键词： infrared:ISM ISM:structure planetary nebulae:individual(M2–55 and Abell 2) stars:AGB and post-AGB

Chromospheric activity on the late-type star V1355 Ori using Lijiang 1.8-m and 2.4-m telescopes

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Research in Astronomy and Astrophysics 2016年第10期16卷 27-34页

作者： Qing-Feng Pi Li-Yun zhang liang Chang xian-Ming Han Hong-Peng Lu xi-liang zhang Dai-Mei Wang College of Physics/Department of Physics and Astronomy Guizhou University Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Mingde College Guizhou University Yunnan Observatories Chinese Academy of Sciences Dept.of Physics and Astronomy Butler University

We obtained new high-resolution spectra using the Lijiang 1.8-m and 2.4-m telescopes to inves- tigate the chromospheric activities of V1355 Ori as indicated in the behaviors of Ca n H＆K, Hγ HT, H/3, Na1 D1, D2, Ha and Ca II infrared triplet （IRT） lines. The observed spectra show obvious emissions above the continuum in Ca II H＆K lines, absorptions in the Hδ, Hγ, H/3 and NaI D1, D2 lines, variable behavior （filled-in absorption, partial emission with a core absorption component or emission above the continuum） in the Ha line, and weak self-reversal emissions in the strong filled-in absorptions of the Ca II IRT lines. We used a spectral subtraction technique to analyze our data. The results show no excess emission in the H6 and H7 lines, very weak excess emissions in the Na I D1, D2 lines, excess emission in the H/3 line, clear excess emission in the Ha line, and excess emissions in the Ca II IRT lines. The value of the ratio of EWs542/EWsa9s is in the range 0.9 to 1.7, which implies that chromospheric activity might have been caused by plage events. The value of the ratio EHδ/EHβ is above 3, indicating that the Balmer lines would arise from prominence-like material. We also found time variations in light curves associated with equiva- lent widths of chromospheric activity lines in the Na I D1, phenomena can be explained by plage events, which are activity indicators. D2, Ca II IRT and Ha lines in particular. These consistent with the behavior of chromospheric

关键词： stars: chromosphere- stars: activity -- stars: individual (V1355 Ori)

An Exposure Meter of Lijiang Fiber-fed High-Resolution Spectrograph

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Research in Astronomy and Astrophysics 2023年第11期23卷 60-66页

作者： xiao-Guang Yu Kai-Fan Ji xi-liang zhang liang Chang Yun-Fang Cai Ying Qin Zhen-Hong Shang Yunnan Observatories Chinese Academy of SciencesKunming 650011China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650216China University of Chinese Academy of Sciences Beijing 100049China Faculty of Information Engineering and Automation Kunming University of Science and TechnologyKunming 650500China

In 2016,an exposure meter was installed on the Lijiang Fiber-fed High-Resolution Spectrograph to monitor the coupling of starlight to the science fiber during *** on it,we investigated a method to estimate the exposure flux of the CCD in real time by using the counts of the photomultiplier tubes(PMT)of the exposure meter,and developed a piece of software to optimize the control of the exposure ***,by using flat-field lamp observations,we determined that there is a linear and proportional relationship between the total counts of the PMT and the exposure flux of the ***,using historical observations of different spectral types,the corresponding relational conversion factors were determined and obtained ***,the method was validated using actual observation data,which showed that all values of the coefficient of determination were greater than ***,software was developed to display the counts of the PMT and the estimated exposure flux of the CCD in real-time during the observation,providing a visual reference for optimizing the exposure time control.

关键词： telescopes instrumentation:spectrographs instrumentation:photometers

Astrometry of three near Earth asteroids with the Lijiang 2.4 m telescope

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Research in Astronomy and Astrophysics 2015年第3期15卷 435-442页

作者： xi-liang zhang Yong Yu Xue-Li Wang Chuan-Jun Wang liang Chang Yu-Feng Fan Zheng-Hong Tang Yunnan Observatories Chinese Academy of Sciences Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Shanghai Astronomical Observatory Chinese Academy of Sciences

Under the framework of observational campaigns organized by the GAIA Follow Up Network for Solar System Objects, three near Earth asteroids, 367943 Duende, 99942 Apophis and 2013 TV135, were observed with the Lijiang 2.4m telescope administered by Yunnan Observatories. The software package PRISM was used to calibrate the CCD fields and measure the positions of 99942 Apophis and 2013 TV135, and our own software was used for 367943 Duende. A comparison of the results show that the ephemerides of INPOP10a and JPL are consistent for 99942 Apophis and 2013 TV135, however, they are quite inconsistent for 367943 Duende. Moreover, we have found that differences between the mean values in the ephemerides of INPOP10a and JPL are about 72＂ and -199＂ in right ascension and declination respectively for 367943 Duende. Moreover, the ephemeris published by JPL is reliable in terms of the mean observed-minus-calculated （O - C） residuals in right ascension and declination of about 2.72＂ and 1.49＂ respectively.

关键词： astrometry -- near Earth objects -- astrometric observation --ephemerides

Effect of annealing time and phosphorus addition on bake hardening behavior of ultra-low carbon bake hardening steel

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Journal of Iron and Steel Research International 2018年第12期25卷 1287-1295页

作者： xi-liang zhang Hua-feng Hou Tao Liu Qian Zhou Hong-ji Liu Yu-long zhang Hao-xuan Cui Zheng Lv College of Mechanical and Equipment Engineering Hebei University of EngineeringHandan 056038HebeiChina

The relationship of the P and C grain boundary segregation and its effect on bake hardening behavior were investigated in ultra-low carbon bake hardening (ULC-BH)steel with and without P addition annealed at 810 ℃ for various time using electron probe micro-analyzer,electroh backscattered diffraction,and three-dimensional atomic probe *** revealed that P addition and annealing duration considerably affected the bake hardening behavior of experimental steel. The BH value of ULC-BH steel without P addition is lower than that with P addition within a short annealing time,and the difference in the BH value gradually decreases as the annealing duration is prolonged.P segregation is dominant in terms of a high P bulk content in steels with P addition at the expense of C segregation during *** contrast,opposite effects are observed in low carbon bake hardening *** high residual solute C content in steel with P addition is due to P segregation at the grain *** competition is mainly responsible for the lower BH value in ULC-BH steel without P addition than that with P *** the annealing time is further extended,C segregation begins at grain boundary despite the delayed P segregation,leading to a gradual decrease in the solute concentration in the matrix of steels with P addition.C and P segregations reach the equilibrium as the annealing time increases to 60 min at 810 ℃ in the two steel *** calculations reveal that the residual solute C concentration in the matrix decreases to zero,and this finding is consistent with the change trend of the bake hardening ***,the C segregation at grain boundary. adversely influences the bake hardening property of ULC-BH steel.

关键词： Ultra-low carbon bake hardening steel Carbon Phosphorus addition Bake hardening behavior Grain boundary segregation