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LAMOST medium-resolution spectral survey of Galactic nebulae(LAMOST-MRS-N):subtraction of geocoronal Hαemission

Research in Astronomy and Astrophysics 2021年第11期21卷 89-97页

作者： Wei Zhang Hong Wu Chao-Jian Wu Juan-Juan Ren Jian-Jun Chen Chih-Hao Hsia Yu-zhong Wu Hui Zhu Jian-Rong Shi zhong-Rui bai Zhao-Xiang Qi Yong-Heng Zhao Yong-Hui Hou CAS Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China CAS Key Laboratory of Space Astronomy and Technology National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China State Key Laboratory of Lunar and Planetary Sciences Macao University of Science and TechnologyTaipaMacaoChina Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China Nanjing Institute of Astronomical Optics&Technology National Astronomical ObservatoriesChinese Academy of SciencesNanjing 210042China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China

We introduce a method of subtracting geocoronal Hαemissions from the spectra of LAMOST medium-resolution spectral survey of Galactic nebulae(LAMOST-MRS-N).The flux ratios of the Hαsky line to the adjacent OHλ6554 single line do not show a pattern or gradient distribution in a *** interestingly,the ratio is well correlated to solar altitude,which is the angle of the Sun relative to the Earth’s *** is found that the ratio decreases from 0.8 to 0.2 with the decreasing solar altitude from–17 to–73 *** on this relation,which is described by a linear function,we can construct the Hαsky component and subtract it from the science *** method has been applied to the LAMOST-MRSN data,and the contamination level of the Hαsky to nebula is reduced from 40%to less than 10%.The new generated spectra will significantly improve the accuracy of the classifications and the measurements of physical parameters of Galactic nebulae.

关键词： techniques:spectroscopic instrumentation:spectrographs ISM:general

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Research on the Characteristics of Deep and Shallow Structures in Shenyang City and Their Relationship with Seismic Activities

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Earthquake Research in China 2010年第2期24卷 255-262页

作者： Wu Mingda zhong Yizhang bai Yun Earthquake Administration of Liaoning Province Shenyang 110034 China

Deep and shallow tectonic data in Shenyang and its relationship with seismic activity shows that the NE trending faults developed on the surface control the formation and development of the fault-uplift and fault-depression. The uplift and depression of the bedrock at a depth of 7km underground are＇consistent with the surface structure. 12 planar listric normal faults have developed above a depth of 18km -20km and two deep faults have developed in the lower crust. Because of the deep incision and new activities, the surface Wanggangpu-Xinehengzi fault and Yongle-Qingshuitai fault, which correspond to the deep F3 fault and F6 fault, might be related to seismic activity in Shenyang.

关键词： Deep tectonic structure Shallow tectonic structure Earthquake Shenyang city

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EXPERIMENTAL STUDY OF THE ASYNCHRONOUS MULTISPLITTING RELAXATION METHODS FOR THE LINEAR COMPLEMENTARITY PROBLEMS

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Journal of Computational Mathematics 2002年第6期20卷 561-574页

作者： zhong-zhi bai(State Key Laboratory of Scientific/Engineering Computing, Institute of Computational Mathematicsand Scientific/Engineering Computing, Academy of Mathematics and System Sciences, ChineseAcademy of Sciences, Beijing 100080, China) Institute of Computational Mathematics and Scientific/Engineering Computing Academy of Mathematics and System Sciences Chinese Academy of Sciences State Key Laboratory of Scientific/Engineering ComputingCAS 北京 100080

Presents a study of the numerical behaviors of the relaxed asynchronous multisplitting methods for linear complementarity problems by solving typical problems from practical applications on a real multiprocessor system. Description of the tested problems and computing environment used in the computations; Description of the asynchronous multisplitting unsymmetric accelerated overrelaxation method; Discussion of results.

关键词： linear complementarity problem matrix multisplitting asynchronous iterative methods numerical experiment

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Electronic Structures and Spectra of the Bases and Base Pairs of Nucleic Acids

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Chemical Research in Chinese Universities 1992年第2期8卷 89-95页

作者： WANG Zhi-zhong and bai Ya-wen (Institute of Theoretical Chemistry, Jilin University, Changchun, 130023)

The present paper covers electronic structures and spectra of the bases and the base pairs of nucleic acids calculated by using the INDO/S method. For free bases we give the energy levels of ground states and transition energies of low-lying excited states and discuss the band characters. The results indicate that the calculated spectra are in good agreement with experimental values. On the other hand, our calculations for A-T and G-C pairs are very beneficial to understanding hydrogen bond properties of these pairs.

关键词： Bases and base pairs of nucleic acid Electronic structures and spectra,INDO/S

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Focused Section on Matrix Computations

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Communications on Applied Mathematics and Computation 2021年第1期3卷 107-107页

作者： zhong-Zhi bai Institute of Computational Mathematics Academy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China

During April 19–23,2019,the International Workshop on Matrix Computations—Gene Golub Memorial Day 2019,was held at Lanzhou University,Lanzhou,*** 60 senior researchers,young scholars,and graduate students attended this workshop,including several famous numerical linear algebraists such as Michele Benzi from Italy,Walter Gander and Martin *** from Switzerland,Wai-Ki Ching and Franklin *** from Hong Kong,China,and Yu-Jiang Wu from the mainland of *** the workshop,the winners of the“Gene Golub Memorial Workshop Best Presentation Prize”were Zeng-Qi Wang from Shanghai Jiao Tong University(for the best oral presentation)and Jun-Feng Yin from Tongji University(for the best poster presentation),both from Shanghai,*** of the winners received a plaque,a certificate,and some kind of gifts.

关键词： Focus mainland Walter

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PARALLEL CHAOTIC MULTISPLITTING ITERATIVE METHODS FOR THE LARGE SPARSE LINEAR COMPLEMENTARITY PROBLEM

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Journal of Computational Mathematics 2001年第3期19卷 281-292页

作者： zhong-zhi bai (State Key Laboratory of Scientific/Engineering Competing Institute of Computational Mathematics and Scientific/Engineering Computing, Academy of Mathematics and Systems Sciences, Chinese Academy of Sciences, Beijing 100080, China) 中科院计算数学与工程计算数学所科学与工程计算国家重点实验室北京 100080

Focuses on a study which presented a parallel chaotic multisplitting method for solving the large sparse linear complementarity problem. Preliminaries of the study; Equations of the parallel chaotic multisplitting met... 详细信息

关键词： linear complementarity problem matrix multisplitting chaotic iteration relaxed method convergence property

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An in-depth Exploration of LAMOST Unknown Spectra Based on Density Clustering

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Research in Astronomy and Astrophysics 2023年第5期23卷 52-65页

作者： Hai-Feng Yang Xiao-Na Yin Jiang-Hui Cai Yu-Qing Yang A-Li Luo zhong-Rui bai Li-Chan Zhou Xu-Jun Zhao Ya-Ling Xun Shanxi Key Laboratory of Big Data Analysis and Parallel Computing Taiyuan University of Science and TechnologyTaiyuan 030024China School of Computer Science and Technology Taiyuan University of Science and TechnologyTaiyuan 030024China School of Computer Science and Technology North University of ChinaTaiyuan 030051China National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China

Large sky Area Multi-Object fiber Spectroscopic Telescope(LAMOST) has completed the observation of nearly 20 million celestial objects,including a class of spectra labeled “Unknown.” Besides low signal-to-noise ratio,these spectra often show some anomalous features that do not work well with current *** this paper,a total of 637,889 “Unknown” spectra from LAMOST DR5 are selected,and an unsupervised-based analytical framework of “Unknown” spectra named SA-Frame(Spectra Analysis-Frame) is provided to explore their origins from different *** SA-Frame is composed of three parts:NAPC-Spec clustering,characterization and origin ***,NAPC-Spec(Nonparametric density clustering algorithm for spectra) characterizes different features in the “unknown” spectrum by adjusting the influence space and divergence distance to minimize the effects of noise and high dimensionality,resulting in 13 ***,characteristic extraction and representation of clustering results are carried out based on spectral lines and continuum,where these 13 types are characterized as regular spectra with low S/Ns,splicing problems,suspected galactic emission signals,contamination from city light and un-gregarious type ***,a preliminary analysis of their origins is made from the characteristics of the observational targets,contamination from the sky,and the working status of the *** results would be valuable for improving the overall data quality of large-scale spectral surveys.

关键词： methods data analysis-surveys-techniques spectroscopic-site testing-methods analytical

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On the radial velocity calibrations in the LAMOST medium-resolution spectroscopic survey of nebulae

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Research in Astronomy and Astrophysics 2021年第3期21卷 1-14页

作者： Juan-Juan Ren Hong Wu Chao-Jian Wu Wei Zhang Jian-Jun Chen Chih-Hao Hsia Fan Yang Chao Liu Jian-Rong Shi Yu-zhong Wu Hui Zhu Bin Li zhong-Rui bai Hao Tian Yong-Hui Hou CAS Key Laboratory of Space Astronomy and Technology National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China CAS Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China State Key Laboratory of Lunar and Planetary Sciences Macao University of Science and TechnologyTaipaMacaoChina University of Chinese Academy of Sciences Beijing 100049China Purple Mountain Observatory Chinese Academy of SciencesNanjing 210008China University of Science and Technology of China Hefei 230026China Nanjing Institute of Astronomical Optics&Technology National Astronomical ObservatoriesChinese Academy of SciencesNanjing 210042China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China

Accurate radial velocity determinations of optical emission lines(i.e.,[NⅡ]λλ6548,6584,Hαand[SⅡ]λλ6717,6731)are very important for investigating the kinematic and dynamic properties of *** second stage survey program of Large sky Area Multi-Object fiber Spectroscopic Telescope(LAMOST)has started a sub-survey of nebulae(MRS-N)which will spectroscopically observe the optical emission lines of a large sample of nebulae near the Galactic *** now,15 MRS-N plates have been observed from September 2017 to June *** on fitting the sky emission lines in the red band spectra of MRS-N,we investigate the precision of wavelength calibration and find there are systematic deviations of radial velocities(RVs)from~0.2 to 4 km s^(-1) for different *** for the plates obtained in March 2018,the systematic deviations of RVs can be as large as~4 km s^(-1),which then go down to~0.2-0.5 kms^(-1) at the end of 2018 and January *** RV calibration function is proposed for these MRS-N plates,which can simultaneously and successfully calibrate the systematic deviations and improve the precision of RVs.

关键词： ISM:general ISM:kinematics and dynamics technique:spectroscopic technique:radial velocities

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Synthesis of fulleropyrrolidine derivatives of C_(60)

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Chinese Science Bulletin 1997年第14期42卷 1180-1184页

作者： LI Yuliang, ZHENG Dagui, XU Juhua, MAO zhong, YANG Jingkui, bai Fenglian and ZHU DaobenInstitute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China Institute of Chemistry Chinese Academy of Sciences Beijing China

1 Experimental ORGANIC chemical derivatization of fullerene by cycloaddition reactions has attracted in-tense interest. It has been found that C60 can undergo a series of cycloaddition reactions associ-ated with poorly-conjugated and electron-deficient alkenes, including [4+2], [3+2], [2+2] and [2+1] cycloaddition reaction, 1, 3-dipolar cycloaddition reactions. [3+2] cycloaddi-tion reactions of azomethine ylides to C60 have been widely used to prepare N-substituted

关键词： fullerene pyrrolidine 1 3-dipolar.

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Relative flux calibration for the Guoshoujing Telescope (LAMOST)

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Research in Astronomy and Astrophysics 2012年第4期12卷 453-464页

作者： Yi-Han Song A-Li Luo Georges Comte zhong-Rui bai Jian-Nan Zhang Wei Du Hao-Tong Zhang Jian-Jun Chen Fang Zuo Yong-Heng Zhao National Astronomical Observatories Chinese Academy of SciencesBeijing 100012China Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100012China Graduate University of Chinese Academy of Sciences Beijing 100049China Observatoire Astronomique Marseille-Provence and Laboratoire d'Astrophysique de Marseille F-13388 Marseille CedexFrance

This paper presents a relative flux calibration method for the Guoshoujing Telescope （LAMOST）, which may be applied to connect a blue spectrum to a red spectrum to build the whole spectrum across the total wavelength range （3700 ～ 9000 A）. In each spectrograph, we estimate the effective temperatures of selected stars using a grid of spectral line indices in the blue spectral range and a comparison with stellar atmosphere models. For each spectrograph, stars of types A and F are selected as pseudo-standard stars, and the theoretical spectra are used to calibrate both the blue （3700 ～ 5900 A） and red spectrograph arms （5700 ～ 9000 A）. Then the spectral response function for these pseudo-standard stars could be used to correct the raw spectra provided by the other fibers of the spectrograph, after a fiber efficiency function has been derived from twilight flat-field exposures. A key problem in this method is the fitting of a pseudo stellar continuum, so we also give a detailed description of this step. The method is tested by comparing a small sample of LAMOST spectra calibrated in this way on stars also observed by the Sloan Digital Sky Survey. The result shows that the T eff estimation and relative flux calibration method are adequate.

关键词： techniques: spectroscopic — calibration: methods:data analysis

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