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BSEC Method for Unveiling Open Clusters and its Application to Gaia DR3:83 New Clusters

Research in Astronomy and Astrophysics 2024年第5期24卷 169-184页

作者： Zhong-Mu Li cai-yan mao Institute of Astronomy and Information Dali UniversityDali 671003China

Open clusters(OCs) are common in the Milky Way, but most of them remain undiscovered. There are numerous techniques, including some machine-learning algorithms, available for the exploration of OCs. However, each method has its limitations and therefore, different approaches to discovering OCs hold significant values. We develop a comprehensive approach method to automatically explore the data space and identify potential OC candidates with relatively reliable membership determination. This approach combines the techniques of Hierarchical Density-Based Spatial Clustering of Applications with Noise, Gaussian mixture model, and a novel cluster member identification technique, color excess constraint. The new method exhibits efficiency in detecting OCs while ensuring precise determination of cluster memberships. Because the main feature of this technique is to add an extra constraint(EC) for the members of cluster candidates using the homogeneity of color excess,compared to typical blind search codes, it is called Blind Search-Extra Constraint(BSEC) method. It is successfully applied to the Gaia Data Release 3, and 83 new OCs are found, whose color–magnitude diagrams(CMDs) are fitted well to the isochrones. In addition, this study reports 621 new OC candidates with discernible main sequence or red giant branch. It is shown that BSEC technique can discard some false negatives of previous works, which takes about three percentage of known clusters. It shows that as an EC, the color excess(or twocolor) constraint is useful for removing fake cluster member stars from the clusters that are identified from the positions and proper motions of stars, and getting more precise CMDs, when differential reddening of member stars of a cluster is not large(e.g., ΔE(G_(BP)-G_(RP)) < 0.5 mag). It makes the CMDs of 15% clusters clearer(in particular for the region near turnoff) and therefore is helpful for CMD and stellar population studies. Our result suggests that the color excess con

关键词： Galaxy stellar content-(Galaxy:)open clusters and associations general-stars fundamental parameters

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A database of spectral energy distributions of progenitors of core-collapse supernovae

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Research in Astronomy and Astrophysics 2021年第9期21卷 1-10页

作者： Zhong-Mu Li cai-yan mao Institute for Astronomy and History of Science and Technology Dali UniversityDali 671003China

This paper presents a database of the spectroscopic-and photometric-spectral energy distributions(spec-SEDs and phot-SEDs respectively)of the progenitors of core-collapse supernovae(CCSNe).Both binary-and single-star progenitors are included in the *** database covers the initial metallicity(Z)range of 0.0001-0.03,mass range of 8-25 M⊙,binary mass ratio range of 0-1,and orbital period range of 0.1-10000 *** low-resolution spec-SEDs and phot-SEDs of single-and binary-star CCSN progenitors are included in the *** data can be used for studying the basic parameters,e.g.,metallicity,age,and initial and final masses of CCSN *** can also be used for studying the effects of different factors on the determination of parameters of CCSN *** the database is utilized for fitting the SEDs of binary-star CCSN progenitors,it is strongly suggested to determine the metallicity and orbital period in advance,but this is not necessary for single-star progenitors.

关键词： (stars:)supernovae:general astronomical databases (stars:)binaries:general

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A binary study of color-magnitude diagrams of 12 globular clusters

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Research in Astronomy and Astrophysics 2010年第2期10卷 135-141页

作者： Zhong-Mu Li cai-yan mao Ru-Heng Li Ru-Xi Li mao-cai Li College of Physics and Electronic Information Dali University Dali 671003 China National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China

Binary stars are common in star clusters and galaxies, but the detailed ef- fects of binary evolution are not taken into account in some color-magnitude diagram （CMD） studies. This paper studies the CMDs of twelve globular clusters via binary- star stellar populations. The observational CMDs of the star clusters are compared to those of binary-star populations, and then the stellar metallicities, ages, distances and reddenings of these star clusters are obtained. The paper also tests the different effects of binary and single stars on CMD studies. It is shown that binaries can better fit the observational CMDs of the sample globular clusters compared to single stars. This suggests that the effects of binary evolution should be considered when modeling the CMDs and stellar populations of star clusters and galaxies.

关键词： (Galaxy:) globular clusters: general -- galaxies: star clusters

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Synthesis and molecular recognition characteristics of a tetrapodal benzene cage

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Chinese Chemical Letters 2024年第8期35卷 240-244页

作者： caihong mao yanfeng He Xiaohan Wang yan cai Xiaobo Hu Key Laboratory of the Ministry of Education for Advanced Catalysis Materials College of Chemistry and Materials ScienceZhejiang Normal UniversityJinhua 321004China

In this contribution,we describe the preparation and recognition characteristics of a novel tetrapodal benzene cage(1).The cage can express a wide recognition range without losing selectivity for the object of appropriate size and functional *** key to obtaining the desired structural isomer of 1 is the synthesis and isolation of the o-bis(bromomethyl)benzene precursor(5).Three distinct guests,F^(−)(ex-tremely small size),d-lactate(appropriate size)and l-Asp(branched shape),were selected as examples to demonstrate the recognition characteristics of *** NMR titration studies,they all expressed good binding affinity(K>10^(5) L/mol)in competitive medium(10%DMSO/THF),indicating that 1 has a wide recognition *** highest binding constant was observed for d-lactate,revealing that 1 has good selectivity for d-lactate versus F^(−)and ***,the NMR titration study of F^(−)in DMSO indicates 1 can achieve different binding modes(1:1 and 2:1 guest-host)for small-sized guests,which allows for the further development of binary binding properties and thereafter applications in the field of catalysis.

关键词： Cage molecules Host-guest chemistry Multi-step organic synthesis d-Lactate recognition l-Asp recognition

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Powerful CMD:a tool for color-magnitude diagram studies

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Research in Astronomy and Astrophysics 2017年第7期17卷 77-88页

作者： Zhong-Mu Li cai-yan mao Qi-Ping Luo Zhou Fan Wen-Chang Zhao Li Chen Ru-Xi Li Jian-Po Guo Institute for Astronomy and History of Science and Technology Dali University Key Laboratory for Optical Astronomy National Astronomical ObservatoriesChinese Academy of Sciences College of Science and Technology Puer University

We present a new tool for color-magnitude diagram（CMD） studies, Powerful CMD. This tool is built based on the advanced stellar population synthesis（ASPS） model, in which single stars, binary stars, rotating stars and star formation history have been taken into account. Via Powerful CMD, the distance modulus, color excess, metallicity, age, binary fraction, rotating star fraction and star formation history of star clusters can be determined simultaneously from observed CMDs. The new tool is tested via both simulated and real star clusters. Five parameters of clusters NGC 6362, NGC 6652, NGC 6838 and M67 are determined and compared to other works. It is shown that this tool is useful for CMD studies, in particular for those utilizing data from the Hubble Space Telescope（HST）. Moreover, we find that inclusion of binaries in theoretical stellar population models may lead to smaller color excess compared to the case of single-star population models.

关键词： (stars:) Hertzsprung-Russell and C-M diagrams - (Galaxy:) globular clusters general -galaxies clusters general

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Theoretical screening of cooperative N-bridged dual-atom sites for efficient electrocatalytic nitrogen reduction with remolding insight

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Nano Research 2024年第4期17卷 3413-3422页

作者： Huimei Chen yan yang Chi Jiao Zhiwen Zhuo Junjie mao yan Liu Key Laboratory of Functional Molecular Solids Ministry of EducationCollege of Chemistry and Materials ScienceAnhui Normal UniversityWuhu 241002China

The electrocatalytic nitrogen reduction reaction(e-NRR)is a promising alternative method for the Haber–Bosch ***,it still faces many challenges in searching for high activity,stability,and selectivity catalysts and ascertaining the catalytic mechanism with complete ***,a series of graphene-based N-bridged dual-atom catalysts(M1-N-M2/NC)are systematically investigated via first-principle calculation and a high-throughput screening *** result unveils that N_(2) adsorption on M1-N-M2/NC in bridge-on adsorption mode can effectively break the scaling relationship on single-atom catalysts(SACs).Moreover,V-N-Ru/NC and V-N-Os/NC are systematically screened out as promising e-NRR catalysts,with extremely low limiting potentials of-0.20 and-0.18 V,***,the adsorption site competition between*N_(2) and*H,as well as the competitive twin reactions of hydrogen evolution reaction(HER)on intermediates(N_(n)H_(m))during the e-NRR process,is systematically evaluated to form a remodeling insight for the reactions in mechanism,and the e-NRR of new proposed dual-atom catalysts(DACs)is strategically optimized for its high-efficiency performance potential via our remolding insight in e-NRR *** work provides new ideas and insights for the design and mechanism of e-NRR catalysts and an effective strategy for rapidly screening highly efficient e-NRR catalysts.

关键词： nitrogen reduction dual-atom catalysts high-throughput screening hydrogen evolution reaction density functional theory calculations

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Comparison of the Minimum Bounding Rectangle and Minimum Circumscribed Ellipse of Rain Cells from TRMM

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Advances in Atmospheric Sciences 2024年第3期41卷 391-406页

作者： Hongke cai Yaqin mao Xuanhao ZHU Yunfei FU Renjun ZHOU Plateau Atmospheric and Environment Laboratory of Sichuan Province School of Atmospheric SciencesChengdu University of Information TechnologyChengdu 610225China School of Earth and Space Sciences University of Science and Technology of ChinaHefei 230026China Center for Atmospheric Optics Anhui Institute of Optics and Fine MechanicsChinese Academy of SciencesHefei 230031China

Based on the TRMM dataset, this paper compares the applicability of the improved MCE(minimum circumscribed ellipse), MBR(minimum bounding rectangle), and DIA(direct indexing area) methods for rain cell fitting. These three methods can reflect the geometric characteristics of clouds and apply geometric parameters to estimate the real dimensions of rain cells. The MCE method shows a major advantage in identifying the circumference of rain cells. The circumference of rain cells identified by MCE in most samples is smaller than that identified by DIA and MBR, and more similar to the observed rain cells. The area of rain cells identified by MBR is relatively robust. For rain cells composed of many pixels(N> 20), the overall performance is better than that of MCE, but the contribution of MBR to the best identification results,which have the shortest circumference and the smallest area, is less than that of MCE. The DIA method is best suited to small rain cells with a circumference of less than 100 km and an area of less than 120 km^(2), but the overall performance is mediocre. The MCE method tends to achieve the highest success at any angle, whereas there are fewer “best identification”results from DIA or MBR and more of the worst ones in the along-track direction and cross-track direction. Through this comprehensive comparison, we conclude that MCE can obtain the best fitting results with the shortest circumference and the smallest area on behalf of the high filling effect for all sizes of rain cells.

关键词： TRMM minimum bounding rectangle minimum circumscribed ellipse

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Sensitivity and resistance risk analysis of Didymella bryoniae populations to fluopyram

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Journal of Integrative Agriculture 2024年第7期23卷 2306-2317页

作者： Zhiwen Wu Xiaowei cai Xuewei mao Mingguo Zhou Yiping Hou College of Plant Protection Nanjing Agricultural UniversityNanjing 210095China

Fluopyram is an succinate dehydrogenase inhibitors(SDHI)fungicide that has been registered in China to control gummy stem blight(GSB)in watermelons for many ***,whether the field pathogens of GSB are still sensitive to fluopyram or not is ***,we collected 69 Didymella bryoniae isolates from the fields that usually use fluopyram to control GSB to determine the sensitivity *** EC_(50)(50%inhibition effect)values of fluopyram against *** ranged from 0.0691 to 0.3503μg mL^(–1) and the variation factor was *** mean EC_(50) value was(0.1579±0.0669)μg mL^(–1) and the curve of sensitivity was *** resistant strains were found in the isolates,which means that the pathogens were still sensitive to *** minimal inhibition concentration(MIC)of fluopyram against *** was 3μg mL^(–1).Four low-resistant mutants and two medium-resistant mutants were obtained using fungicide taming and the resistance of mutants could be inherited *** growth rate of mutants decreased significantly compared with that of wild-type strains while the biomass of most mutants was similar to that of wild-type *** sensitivity of most resistant mutants to various stresses was increased compared with that of wild-type *** virulence of mutants receded except for low-resistant mutant XN51FR-1,which had the same lesion area as XN51 on the watermelon *** results indicated that the fitness of resistant mutants was decreased compared with that of wild-type *** cross-resistance assay indicated that fluopyram-resistant mutants were positive cross-resistant to all six SDHI fungicides in this test but were still sensitive to fluazinam and *** the resistance risk of *** to fluopyram was *** addition,we found that the SdhB gene of low-resistant mutant XN30FR-1 had three new point mutations at positions K258N,A259P,and ***-resistant mutant XN52FR-1 showed a mutation at position H277N an

关键词： fluopyram D.bryoniae sensitivity risk assessment

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A novel method for determining the resistivity of compressed superconducting materials

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Matter and Radiation at Extremes 2024年第4期9卷 1-3页

作者： Liling Sun Qi Wu Shu cai yang Ding Ho-kwang mao Center for High Pressure Science and Technology Advanced Research Beijing 100094China Institute of Physics Chinese Academy of SciencesBeijing 100190China

The measurement of resistivity in a compressed material within a diamond anvil cell presents significant *** high-pressure exper-imental setup makes it difficult to directly measure the size changes induced by pressure in the three crystallographic directions of the *** this study,we introduce a novel and effective method that addresses these technical *** method is anticipated to offer a valuable foundation for high-pressure investigations on quantum materials,particularly those with anisotropic layered structures.

关键词： resistivity method foundation

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Frequency and associated factors of accommodation and non-strabismic binocular vision dysfunction among medical university students

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International Journal of Ophthalmology(English edition) 2024年第2期17卷 374-379页

作者： Jie cai Wen-Wen Fan Yun-Hui Zhong cai-Lan Wen Xiao-Dan Wei Wan-Chen Wei Wan-yan Xiang Jin-mao Chen Department of Ophthalmology First Affiliated Hospital of Guangxi Medical UniversityNanning 530021Guangxi Zhuang Autonomous RegionChina Digital and Intelligent Technology Transformation and Application Research Institute of Visual Function Tianjin 300000China Guangxi Medical University Nanning 530021Guangxi Zhuang Autonomous RegionChina

AIM:To investigate the frequency and associated factors of accommodation and non-strabismic binocular vision dysfunction among medical university ***:Totally 158 student volunteers underwent routine vision examination in the optometry clinic of Guangxi Medical *** data were used to identify the different types of accommodation and nonstrabismic binocular vision dysfunction and to determine their *** analysis and logistic regression were used to examine the factors associated with these ***:The results showed that 36.71%of the subjects had accommodation and non-strabismic binocular vision issues,with 8.86%being attributed to accommodation dysfunction and 27.85%to binocular *** insufficiency(CI)was the most common abnormality,accounting for 13.29%.Those with these abnormalities experienced higher levels of eyestrain(χ2=69.518,P<0.001).The linear correlations were observed between the difference of binocular spherical equivalent(SE)and the index of horizontal esotropia at a distance(r=0.231,P=0.004)and the asthenopia survey scale(ASS)score(r=0.346,P<0.001).Furthermore,the right eye's SE was inversely correlated with the convergence of positive and negative fusion images at close range(r=-0.321,P<0.001),the convergence of negative fusion images at close range(r=-0.294,P<0.001),the vergence facility(VF;r=-0.234,P=0.003),and the set of negative fusion images at far range(r=-0.237,P=0.003).Logistic regression analysis indicated that gender,age,and the difference in right and binocular SE did not influence the emergence of these ***:Binocular vision abnormalities are more prevalent than accommodation dysfunction,with CI being the most frequent *** binocular refractive disparity leads to more severe eyestrain symptoms.

关键词： optometry clinic non-strabismic binocular vision dysfunction college students convergence insufficiency

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