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The Inclination, Pitch Angle and Forbidden Radius of Spiral Arms of PGC 35105

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Chinese Journal of Astronomy and Astrophysics 2006年第2期6卷 175-180页

作者： Tao Hu zheng-yi shao Qiu-He Peng Department of Astronomy Nanjing University Nanjing 210093 Shanghai Astronomical Observatory Chinese-Academy of Sciences Shanghai 200030 Joint Institute for Galaxies and Cosmology Chinese Academy of Sciences Shanghai 200030 Joint Astrophysics Center of Chinese Academy of Sciences-Peking University Beijing 100871 The Open Laboratory of Cosmic Ray and High Energy Astrophysics Chinese Academy otSciences Beijing 100049

We have studied some properties including surface brightness in the u, g, r, i, and z bands of the nearly face-on galaxy PGC 35105. By subtracting a model surface brightness distribution from the observed image we obtain the residual image that shows only the spiral arms freed from the contamination by the bulge. From this we measured the the inclination, pitch angle, and forbidden radius （identified with the innermost point of the arm） for each of the two arms; and that for each of the five observing bands. We found these three parameters are largely independent of the observing band.

关键词： galaxies: fundamental parameters - galaxies: spiral - galaxies: structure - galaxies: surface brightness - galaxies: individual (PGC 35105)

Searching for classical Be stars in LAMOST DR1

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Research in Astronomy and Astrophysics 2015年第8期15卷 1325-1331页

作者： Chien-Cheng Lin Jin-Liang Hou Li Chen zheng-yi shao Jing Zhong Po-Chieh Yu Shanghai Astronomical Observatory Chinese Academy of Sciences Department of Physics and Astronomy University of CaliforniaLos AngelesCA 90024USA

We report on searching for Classical B-type emission-line（CBe） stars in the first data release of the Large Sky Area Multi-Object fiber Spectroscopic Telescope（LAMOST; also called the Guo Shou Jing Telescope）. A total of 192 objects（including 12 previously known CBes） were identified as CBe candidates with prominent He I λ4387, He I λ4471 and Mg II λ4481 absorption lines, as well as Hβλ4861and Hαλ6563 emission lines. These candidates significantly increase the currently known sample of CBes by about 8%. Most of the CBe candidates are distributed near the Galactic Anti-Center due to the observing strategy used for LAMOST. Only two CBes are in star clusters. These two CBes have ages of 15.8 and 398 Myr, respectively.

关键词： stars: emission-line—Be—stars: early-type—open clusters and associations: general

Color gradients of spiral disks in the Sloan Digital Sky Survey

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Research in Astronomy and Astrophysics 2009年第10期9卷 1119-1130页

作者： Cheng-Ze Liu Shi-yin Shen zheng-yi shao Rui-Xiang Chang Jin-Liang Hou Jun yin Da-Wei Yang Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai 200030 China Graduate University of Chinese Academy of Sciences Beijing 100049 China Key Laboratory for Astrophysics Shanghai 200234 China Department of Physics Hebei Normal University Shijiazhuang 050016 China

We investigate the radial color gradients of galactic disks using a sample of - 20 000 face-on spiral galaxies selected from the fourth data release of the Sloan Digital Sky Survey （SDSS-DR4）. We combine galaxies with similar concentrations, sizes and luminosities to construct composite galaxies, and then measure their color profiles by stacking the azimuthally averaged radial color profiles of all the member galaxies. Except for the smallest galaxies （R50 〈 3 kpc）, almost all galaxies show negative disk color gradients with mean 9 - r gradient Ggr = -0.006 magkpc-1 and r - z gradient Grz = -0.018 mag kpc^-1. The disk color gradients are independent of the morphological types of galaxies and strongly dependent on the disk surface brightness μd, with lower surface brightness galactic disks having steeper color gradients. We quantify the intrinsic correlation between color gradients and surface brightness as Ggr = -0.011μd ＋ 0.233 and Grz - -0.015μd ＋ 0.324. These quantified correlations provide tight observational constraints on the formation and evolution models of spiral galaxies.

关键词： galaxies spiral -- galaxies statistics -- galaxies evolution -- galaxies fundamental parameters (color gradient, luminosity, radius, surface brightness)

An isolated compact galaxy triplet

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Research in Astronomy and Astrophysics 2016年第5期16卷 17-24页

作者： Shuai Feng zheng-yi shao Shi-yin Shen Maria Argudo-Femgandez Hong Wu Man-I Lam Ming Yang Fang-Ting Yuan Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical ObservatoryChinese Academy ofSciencesShanghai 200030China University of the Chinese Academy of Sciences Beijing 100049China Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing100012China Key Lab for Astrophysics Shanghai 200234China

We report the discovery of an isolated compact galaxy triplet SDSS J084843.45＋164417.3, which is first detected by the LAMOST spectral survey and then confirmed by a spectroscopic observation of the BFOSC mounted on the 2.16 meter telescope located at Xinglong Station, which is administered by National Astronomical Observatories, Chinese Academy of Sciences. It is found that this triplet is an iso- lated and extremely compact system, which has an aligned configuration and very small radial velocity dispersion. The member galaxies have similar colors and show marginal star formation activities. These results support the opinion that the compact triplets are well-evolved systems rather than hierarchically forming structures. This serendipitous discovery reveals the limitations of fiber spectral redshift surveys in studying such a compact system, and demonstrates the necessity of additional observations to complete the current redshift sample.

关键词： galaxies: group -- galaxies: interaction -- galaxies: star formation -- galaxies: evolution

Single-atom-mediated electron islands boost photocatalytic CO_(2)chemical fixation

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Science China Chemistry 2024年第7期67卷 2292-2299页

作者： Shu Shang Lei Li Xin He Hui Wang Lirong zheng Wei shao Xiaodong Zhang yi Xie Hefei National Research Center for Physical Sciences at the Microscale University of Science and Technology of ChinaHefei 230026China Institute of Energy Hefei Comprehensive National Science CenterHefei 230031China Beijing Synchrotron Radiation Facility Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China School of Chemistry and Chemical Engineering Hefei Normal UniversityHefei 230031China

Photocatalytic cycloadditions of CO_(2)with epoxides are emerging as a significant platform for the green synthesis of valuable carbonates,where efficient catalytic systems with spatially separated charge carriers are ***,a single p-block metal atom is proposed to be a candidate for photogenerated electron localization on a metal oxide *** taking the Bi single-atom supported on ZnO nanosheet(Bi1/ZnO)as an example,we show that the Bi atom plays the role of an electron island in the sea of delocalized holes within ***,the as-formed electron island could readily promote the rate-determining ring-opening process of cycloaddition *** from the unique spatially separated electrons and holes,the Bi1/ZnO achieves a high yield of cyclic carbonates with almost 100%*** study provides a pioneering strategy for enhancing the performances of photocatalytic CO_(2)chemical fixation.

关键词： electron islands CO_(2)photofixation photogenerated charge carriers

The Logarithmic Sobolev Inequality for a Submanifold in Manifolds with Nonnegative Sectional Curvature

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Chinese Annals of Mathematics,Series B 2024年第3期45卷 487-496页

作者： Chengyang yi Yu zheng School of Mathematical Sciences East China Normal UniversityShanghai 200241China

The authors prove a sharp logarithmic Sobolev inequality which holds for compact submanifolds without boundary in Riemannian manifolds with nonnegative sectional curvature of arbitrary dimension and *** the Michael-Simon Sobolev inequality,this inequality includes a term involving the mean *** extends a recent result of Brendle with Euclidean setting.

关键词： Logarithmic Sobolev inequality Nonnegative sectional curvature Submanifold

Adaptive Trajectory Tracking Control for Nonholonomic Wheeled Mobile Robots:A Barrier Function Sliding Mode Approach

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IEEE/CAA Journal of Automatica Sinica 2024年第4期11卷 1007-1021页

作者： Yunjun zheng Jinchuan zheng Ke shao Han Zhao Hao Xie Hai Wang the School of Mechanical Engineering Hefei University of TechnologyHefei 230009China the School of Science Computing and Engineering TechnologiesSwinburne University of TechnologyHawthorn VIC 3122Australia the School of Civil Aviation Northwestern Polytechnical UniversityXi’an 710072China the Shanghai Aerospace Control Technology Institute Shanghai 201109 the School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China the College of Science HealthEngineering and EducationMurdoch UniversityPerth WA6150Australia

The trajectory tracking control performance of nonholonomic wheeled mobile robots(NWMRs)is subject to nonholonomic constraints,system uncertainties,and external *** paper proposes a barrier function-based adaptive sliding mode control(BFASMC)method to provide high-precision,fast-response performance and robustness for *** with the conventional adaptive sliding mode control,the proposed control strategy can guarantee that the sliding mode variables converge to a predefined neighborhood of origin with a predefined reaching time independent of the prior knowledge of the uncertainties and disturbances *** advantage of the proposed algorithm is that the control gains can be adaptively adjusted to follow the disturbances amplitudes thanks to the barrier *** benefit is that the overestimation of control gain can be eliminated,resulting in chattering ***,a modified barrier function-like control gain is employed to prevent the input saturation problem due to the physical limit of the *** stability analysis and comparative experiments demonstrate that the proposed BFASMC can ensure the prespecified convergence performance of the NWMR system output variables and strong robustness against uncertainties/disturbances.

关键词： Adaptive sliding mode barrier function nonholonomic wheeled mobile robot(NWMR) trajectory tracking control

Eat at the right time: Regulation of ER-phagy receptors in plant response to environmental stresses

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Molecular Plant 2024年第2期17卷 236-239页

作者： Yang shao Jiaqi Sun Huanquan zheng The Key Laboratory of Plant Development and Environmental Adaptation Biology Ministry of EducationSchool of Life SciencesShandong UniversityQingdao 266237China Department of Biology McGill UniversityMontrealQC H3A 1B1Canada

The endoplasmic reticulum(ER)is a cellular factory for biosynthesis of proteins and *** accommodate a wide array of biosynthetic demands in responses to environmental stresses,the plant ER remodels to maintain a structural and functional homeostasis.A key process facilitating this balance is selective autophagy of the ER(ER-phagy),where malfunctioned ER is recognized,engulfed by autophagosomes,and then delivered to the vacuole for degradation.

关键词： maintain accommodate function

Differentially private SGD with random features

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Applied Mathematics(A Journal of Chinese Universities) 2024年第1期39卷 1-23页

作者： WANG yi-guang GUO zheng-chu Polytechnic Institute of Zhejiang University Zhejiang UniversityHangzhou 310015China School of Mathematical Sciences Zhejiang UniversityHangzhou 310058China

In the realm of large-scale machine learning,it is crucial to explore methods for reducing computational complexity and memory demands while maintaining generalization ***,since the collected data may contain some sensitive information,it is also of great significance to study privacy-preserving machine learning *** paper focuses on the performance of the differentially private stochastic gradient descent(SGD)algorithm based on random *** begin,the algorithm maps the original data into a lowdimensional space,thereby avoiding the traditional kernel method for large-scale data storage ***,the algorithm iteratively optimizes parameters using the stochastic gradient descent ***,the output perturbation mechanism is employed to introduce random noise,ensuring algorithmic *** prove that the proposed algorithm satisfies the differential privacy while achieving fast convergence rates under some mild conditions.

关键词： learning theory differential privacy stochastic gradient descent random features reproducing kernel Hilbert spaces