Y. Yang

University of Science and Technology of China, Hefei, Anhui Sheng, China

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Publications (11)5.4 Total impact

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    ABSTRACT: We have undertaken a survey of the most massive and overdense galaxy structures in the early universe at z=2-4, traced by regions of the highest optical depth from IGM Lyα absorption over large scale of 10-30 Mpc. These structures represent the most biased regions in the universe at the peak of galaxy formation epoch, bridging the most luminous quasars observed at z∼ 6-7 and the most massive clusters in the local universe. Cosmological simulation and early observations show a strong correlation between the optical depth of 1-D intergalactic Lyα absorption and the 3-D mass overdensities. Based on the simulation and MMT high S/N observations, we have developed a novel technique to identify high-redshift overdense region by searching for high optical depth regions in quasar spectra and requiring that they are not associated with discrete high column density absorbers such as sub-damped Lyα (sub-DLA) or DLA systems. By examining absorption spectra of ∼ 140,000 sight lines provided by SDSS-III quasar survey, we have searched the IGM overdensities over a volume of 10 Gpc^3. This survey volume is more than two orders of magnitude larger than any existing Lyman Break Galaxy survey, enabling the discovery of the rarest and most massive systems. We have selected one unique field with three large Lyα absorption and seven quasars within 20 h^-1 Mpc. Our preliminary and shallow KPNO-4m narrowband + broadband imaging have revealed a significant overdensity of Lyα emitters at bright-end associating with this system. In future, we propose to carry out the LBT/LBC multi-color imaging to probe this field in much deeper using BX galaxies down to L^*, and further take the LBT/MODS observations to spectroscopically follow-up the ∼100 BX galaxies in this most overdense field and map the 3-D structure associated with the largest intergalactic HI overdensity.
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    ABSTRACT: The gas injection system (GIS) is an indispensable part of ITER fueling system. It deliveries the necessary gas species from tritium plant to vacuum vessel, pellet injection system or neutral beam for plasma operation and fusion power shutdown. In this paper, the current design status of GIS, including the previous design changes, is briefly described. As the GIS design justification and support, the experimental study on GIS response time is illustrated. The factors delayed the GIS response time are identified, and two kinds of control mode are proved to be effective for improving the GIS response time. The exploration on magnetic shield design shows the discrepancy of shielding performance occurs in the case of the paralleling external magnetic field to the sample cylinder. These R&D works prove the design feasibility in some ways, and support possible solutions for design challenges as alternative design options.
    Fusion Engineering and Design. 08/2012; 87(s 5–6):813–821.
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    ABSTRACT: 3D visualizations of complex structures within various samples have been achieved with high spatial resolution by X-ray computed nanotomography (nano-CT). While high spatial resolution generally comes at the expense of field of view (FOV). Here we proposed an approach that stitched several 3D volumes together into a single large volume to significantly increase the size of the FOV while preserving resolution. Combining this with nano-CT, 18-mum FOV with sub-60-nm resolution has been achieved for non-destructive D visualization of clustered yeasts that were too large for a single scan. It shows high promise for imaging other large samples in the future.
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    ABSTRACT: A naturally occurring clay mineral, palygorskite, which has the microstructure of nano-fibers, was used to support a metallocene compound, Cp2TiCl2. After activation by methylaluminoxane, the supported catalyst initiated an in situ ethylene polymerization resulting in the exfoliated dispersion of the nano-fibers into the polyethylene matrix. With no further chemical modification of the palygorskite after thermal treatment, the activity of the supported catalyst was found to be even higher than its solution counterpart under the same polymerization conditions. The addition of the filler in the polymer matrix led to an increase in composite rigidity as reflected by almost doubling the storage modulus at room temperature. Moreover, the filler affects the crystallization process, as observed by DSC and solid-state NMR, reducing the crystallinity up to 28% and the thickness of the rigid phase up to 22% compared with the neat sample.
    Polymer 10/2010; · 3.77 Impact Factor
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    ABSTRACT: Cellular structures of the fission yeast, Schizosaccharomyces pombe, were examined by using hard X-ray tomography. Since cells are nearly transparent to hard X-rays, Zernike phase contrast and heavy metal staining were introduced to improve image contrast. Through using such methods, images taken at 8 keV displayed sufficient contrast for observing cellular structures. The cell wall, the intracellular organelles and the entire structural organization of the whole cells were visualized in three-dimensional at a resolution better than 100 nm. Comparison between phase contrast and absorption contrast was also made, indicating the obvious advantage of phase contrast for cellular imaging at this energy. Our results demonstrate that hard X-ray tomography with Zernike phase contrast is suitable for cellular imaging. Its unique abilities make it have potential to become a useful tool for revealing structural information from cells, especially thick eukaryotic cells.
    Journal of Microscopy 10/2010; 240(1):14-20. · 1.63 Impact Factor
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    ABSTRACT: The gas injection of ITER has different functions at different phases. Corresponding to each function, the requirements on throughput, response time and gas species are analyzed in this paper. The requirements due to the concern of safety and control are also discussed. After this overall introduction of system requirements, challenges on design of some key components are outlined. Potential solutions are also listed as reference for ongoing work about gas injection system of ITER.
    Fusion Engineering and Design - FUSION ENG DES. 01/2010; 85(10):2292-2294.
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    ABSTRACT: We present optical observations of BL Lacertae (BL Lac) in the standard BVRI bands using 80 cm TNT Telescope from Sept. 3 to Sept 8 in 2005, and compare our results with the X-ray variability of TeV blazars.
    09/2007; 373:187.
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    ABSTRACT: CBET 804 available at Central Bureau for Astronomical Telegrams.
    Central Bureau Electronic Telegrams. 01/2007;
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    ABSTRACT: IAUC 8798 available at Central Bureau for Astronomical Telegrams.
    International Astronomical Union Circular. 01/2007;
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    ABSTRACT: CBET 335 available at Central Bureau for Astronomical Telegrams.
    Central Bureau Electronic Telegrams. 12/2005;
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    ABSTRACT: IAUC 8647 available at Central Bureau for Astronomical Telegrams.

Publication Stats

4 Citations
5.40 Total Impact Points

Top Journals


  • 2010
    • University of Science and Technology of China
      • National Synchrotron Radiation Laboratory
      Hefei, Anhui Sheng, China
    • Zhejiang University
      • Department of Chemical and Biochemical Engineering
      Hangzhou, Zhejiang Sheng, China
  • 2007
    • Tsinghua University
      Peping, Beijing, China