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Institution

Academia Sinica

FacilityTaipei, Taiwan
About: Academia Sinica is a facility organization based out in Taipei, Taiwan. It is known for research contribution in the topics: Population & Galaxy. The organization has 52086 authors who have published 65998 publications receiving 1728114 citations. The organization is also known as: Central Research Academy.


Papers
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Journal ArticleDOI
TL;DR: An unexpected bandgap tunability with distance from the grain boundary in single-layer molybdenum disulphide is reported, which also depends on the grain misorientation angle.
Abstract: Two-dimensional transition metal dichalcogenides have emerged as a new class of semiconductor materials with novel electronic and optical properties of interest to future nanoelectronics technology. Single-layer molybdenum disulphide, which represents a prototype two-dimensional transition metal dichalcogenide, has an electronic bandgap that increases with decreasing layer thickness. Using high-resolution scanning tunnelling microscopy and spectroscopy, we measure the apparent quasiparticle energy gap to be 2.40 ± 0.05 eV for single-layer, 2.10 ± 0.05 eV for bilayer and 1.75 ± 0.05 eV for trilayer molybdenum disulphide, which were directly grown on a graphite substrate by chemical vapour deposition method. More interestingly, we report an unexpected bandgap tunability (as large as 0.85 ± 0.05 eV) with distance from the grain boundary in single-layer molybdenum disulphide, which also depends on the grain misorientation angle. This work opens up new possibilities for flexible electronic and optoelectronic devices with tunable bandgaps that utilize both the control of two-dimensional layer thickness and the grain boundary engineering.

381 citations

Journal ArticleDOI
TL;DR: It is shown that members of the rice (Oryza sativa) GA2ox family are differentially regulated and act in concert or individually to control GA levels during flowering, tillering, and seed germination and that improvements in plant architecture could be induced by overexpression of wild-type or modified C20 GA 2oxs.
Abstract: Gibberellin 2-oxidases (GA2oxs) regulate plant growth by inactivating endogenous bioactive gibberellins (GAs). Two classes of GA2oxs inactivate GAs through 2β-hydroxylation: a larger class of C19 GA2oxs and a smaller class of C20 GA2oxs. In this study, we show that members of the rice (Oryza sativa) GA2ox family are differentially regulated and act in concert or individually to control GA levels during flowering, tillering, and seed germination. Using mutant and transgenic analysis, C20 GA2oxs were shown to play pleiotropic roles regulating rice growth and architecture. In particular, rice overexpressing these GA2oxs exhibited early and increased tillering and adventitious root growth. GA negatively regulated expression of two transcription factors, O. sativa homeobox 1 and TEOSINTE BRANCHED1, which control meristem initiation and axillary bud outgrowth, respectively, and that in turn inhibited tillering. One of three conserved motifs unique to the C20 GA2oxs (motif III) was found to be important for activity of these GA2oxs. Moreover, C20 GA2oxs were found to cause less severe GA-defective phenotypes than C19 GA2oxs. Our studies demonstrate that improvements in plant architecture, such as semidwarfism, increased root systems and higher tiller numbers, could be induced by overexpression of wild-type or modified C20 GA2oxs.

380 citations

Journal ArticleDOI
03 May 2002-Science
TL;DR: Archaefructaceae is proposed as a new basal angiosperm family of herbaceous aquatic plants and is a sister clade to all angiosperms when their characters are included in a combined three-gene molecular and morphological analysis.
Abstract: Archaefructaceae is proposed as a new basal angiosperm family of herbaceous aquatic plants. This family consists of the fossils Archaefructus liaoningensis and A. sinensis sp. nov. Complete plants from roots to fertile shoots are known. Their age is a minimum of 124.6 million years from the Yixian Formation, Liaoning, China. They are a sister clade to all angiosperms when their characters are included in a combined three-gene molecular and morphological analysis. Their reproductive axes lack petals and sepals and bear stamens in pairs below conduplicate carpels.

377 citations

Journal ArticleDOI
TL;DR: A phylogenetic tree of the Brassicaceae species under study was constructed and showed that the rate of nucleotide substitution in the first intron of the mitochondrial (mt) gene for NADH subunit 4 (nad4) is very low, about 0.16–0.23 × 10−9 substitution per site per year, which is about half of the silent rate in exons of nad4
Abstract: We obtained 16 nucleotide sequences ( approximately 1400 bp each) of the first intron of the mitochondrial (mt) gene for NADH subunit 4 (nad4) from 10 species of Brassicaceae. Using these new sequences and five published sequences from GenBank, we constructed a phylogenetic tree of the Brassicaceae species under study and showed that the rate of nucleotide substitution in the first intron of nad4 is very low, about 0.16-0.23 x 10(-9) substitution per site per year, which is about half of the silent rate in exons of nad4. The ratios of substitution rates in this intron, ITS, and IGS are approximately 1:23:73, where ITS is the nuclear intergenic spacer between 18S and 25S rRNA genes and IGS is the intergenic spacer of 5S rRNA genes. A segment (335 bp) in the first intron of nad4 in Brassicaceae species that is absent in wheat was considered as a nonfunctional sequence and used to estimate the neutral rate (the rate of mutation) in mtDNA to be 0.5-0.7 x 10(-9) substitution per site per year, which is about three times higher than the substitution rate in the rest of the first intron of nad4. We estimated that the dates of divergence are 170-235 million years (Myr) for the monocot-dicot split, 112-156 Myr for the Brassicaceae-Lettuce split, 14.5-20.4 Myr for the Brassica-Arabidopsis split, and 14.5-20.4 Myr for the Arabidopsis-Arabideae split.

377 citations

Journal ArticleDOI
TL;DR: The LAMOST Experiment for Galactic Understanding and Exploration (LEGUE) survey as discussed by the authors is a large-scale survey of millions of stars in the Milky Way galaxy using the Guo Shou Jing Telescope (GSJT).
Abstract: We describe the current plans for a spectroscopic survey of millions of stars in the Milky Way galaxy using the Guo Shou Jing Telescope (GSJT, formerly called the Large sky Area Multi-Object fiber Spectroscopic Telescope - LAMOST). The survey will obtain spectra for 2.5 million stars brighter than r < 19 during dark/grey time, and 5 million stars brighter than r < 17 or J < 16 on nights that are moonlit or have low transparency. The survey will begin in the fall of 2012, and will run for at least four years. The telescope's design constrains the optimal declination range for observations to 10 degrees < delta < 50 degrees, and site conditions lead to an emphasis on stars in the direction of the Galactic anticenter. The survey is divided into three parts with different target selection strategies: disk, anticenter, and spheroid. The resulting dataset will be used to study the merger history of the Milky Way, the substructure and evolution of the disks, the nature of the first generation of stars through identification of the lowest metallicity stars, and star formation through study of open clusters and OB associations. Detailed design of the LAMOST Experiment for Galactic Understanding and Exploration (LEGUE) survey will be completed in summer 2012, after a review of the results of the pilot survey.

376 citations


Authors

Showing all 52129 results

NameH-indexPapersCitations
Yi Chen2174342293080
Jing Wang1844046202769
Jie Zhang1784857221720
Hyun-Chul Kim1764076183227
Yang Yang1642704144071
Yuh Nung Jan16246074818
Jongmin Lee1502257134772
Hui-Ming Cheng147880111921
Teruki Kamon1422034115633
Jian Yang1421818111166
I. V. Gorelov1391916103133
S. R. Hou1391845106563
Kaori Maeshima1391850105218
Jiangyong Jia138117391163
Kenneth Bloom1381958110129
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
202315
2022111
20212,414
20202,356
20192,330
20182,349