Yan-mei Chen

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We present a new method to estimate the average star formation rate per unit stellar mass (SSFR) of a stacked population of galaxies. We combine the spectra of 600−1000 galaxies with similar stellar masses and parameterise the star formation history of this stacked population using a set of exponentially declining functions. The strength of the Hydrogen(More)
Galaxies grow through both internal and external processes. In about 10% of nearby red galaxies with little star formation, gas and stars are counter-rotating, demonstrating the importance of external gas acquisition in these galaxies. However, systematic studies of such phenomena in blue, star-forming galaxies are rare, leaving uncertain the role of(More)
Quiescent galaxies with little or no ongoing star formation dominate the population of galaxies with masses above 2 × 10(10) times that of the Sun; the number of quiescent galaxies has increased by a factor of about 25 over the past ten billion years (refs 1-4). Once star formation has been shut down, perhaps during the quasar phase of rapid accretion onto(More)
Two new tetranorlabdane diterpenoids, named botryosphaerins G (1) and H (2), were isolated from the solid fermentation products of Botryosphaeria sp. P483 along with seven known tetranorlabdane diterpenes (3-9). Their structures were elucidated by extensive analysis, including 1D and 2D nuclear magnetic resonance (NMR) spectroscopy, and high-resolution(More)
For understanding the regional response to climate change, we explain the characteristics and change of landscape patterns at Huihe National Nature Reserve, Hulun Buir, Inner Mongolia, China. By the visual interpretation method and three-period TM images, we generated landscape classification information with the support of the Arcmap software platform and(More)
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