| 1. |
- Abolfathi, Bela, et al.
(författare)
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The Fourteenth Data Release of the Sloan Digital Sky Survey : First Spectroscopic Data from the Extended Baryon Oscillation Spectroscopic Survey and from the Second Phase of the Apache Point Observatory Galactic Evolution Experiment
- 2018
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Ingår i: Astrophysical Journal Supplement Series. - : IOP Publishing Ltd. - 0067-0049 .- 1538-4365. ; 235:2
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Tidskriftsartikel (refereegranskat)abstract
- The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in operation since 2014 July. This paper describes the second data release from this phase, and the 14th from SDSS overall (making this Data Release Fourteen or DR14). This release makes the data taken by SDSS-IV in its first two years of operation (2014-2016 July) public. Like all previous SDSS releases, DR14 is cumulative, including the most recent reductions and calibrations of all data taken by SDSS since the first phase began operations in 2000. New in DR14 is the first public release of data from the extended Baryon Oscillation Spectroscopic Survey; the first data from the second phase of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2), including stellar parameter estimates from an innovative data-driven machine-learning algorithm known as "The Cannon"; and almost twice as many data cubes from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous release (N = 2812 in total). This paper describes the location and format of the publicly available data from the SDSS-IV surveys. We provide references to the important technical papers describing how these data have been taken (both targeting and observation details) and processed for scientific use. The SDSS web site (www.sdss.org) has been updated for this release and provides links to data downloads, as well as tutorials and examples of data use. SDSS-IV is planning to continue to collect astronomical data until 2020 and will be followed by SDSS-V.
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| 2. |
- Aguado, D. S., et al.
(författare)
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The Fifteenth Data Release of the Sloan Digital Sky Surveys : First Release of MaNGA-derived Quantities, Data Visualization Tools, and Stellar Library
- 2019
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Ingår i: Astrophysical Journal Supplement Series. - : Institute of Physics Publishing (IOPP). - 0067-0049 .- 1538-4365. ; 240:2
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Tidskriftsartikel (refereegranskat)abstract
- Twenty years have passed since first light for the Sloan Digital Sky Survey (SDSS). Here, we release data taken by the fourth phase of SDSS (SDSS-IV) across its first three years of operation (2014 July-2017 July). This is the third data release for SDSS-IV, and the 15th from SDSS (Data Release Fifteen; DR15). New data come from MaNGA-we release 4824 data cubes, as well as the first stellar spectra in the MaNGA Stellar Library (MaStar), the first set of survey-supported analysis products (e.g., stellar and gas kinematics, emission-line and other maps) from the MaNGA Data Analysis Pipeline, and a new data visualization and access tool we call "Marvin." The next data release, DR16, will include new data from both APOGEE-2 and eBOSS; those surveys release no new data here, but we document updates and corrections to their data processing pipelines. The release is cumulative; it also includes the most recent reductions and calibrations of all data taken by SDSS since first light. In this paper, we describe the location and format of the data and tools and cite technical references describing how it was obtained and processed. The SDSS website (www.sdss.org) has also been updated, providing links to data downloads, tutorials, and examples of data use. Although SDSS-IV will continue to collect astronomical data until 2020, and will be followed by SDSS-V (2020-2025), we end this paper by describing plans to ensure the sustainability of the SDSS data archive for many years beyond the collection of data.
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| 3. |
- Blanton, Michael R., et al.
(författare)
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Sloan Digital Sky Survey IV : Mapping the Milky Way, Nearby Galaxies, and the Distant Universe
- 2017
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Ingår i: Astronomical Journal. - : IOP Publishing Ltd. - 0004-6256 .- 1538-3881. ; 154:1
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Tidskriftsartikel (refereegranskat)abstract
- We describe the Sloan Digital Sky Survey IV (SDSS-IV), a project encompassing three major spectroscopic programs. The Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) is observing hundreds of thousands of Milky Way stars at high resolution and. high signal-to-noise ratios in the near-infrared. The Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey is obtaining spatially resolved spectroscopy for thousands of nearby galaxies (median z similar to 0.03). The extended Baryon Oscillation Spectroscopic Survey (eBOSS) is mapping the galaxy, quasar, and neutral gas distributions between z similar to 0.6 and 3.5 to constrain cosmology using baryon acoustic oscillations, redshift space distortions, and the shape of the power spectrum. Within eBOSS, we are conducting two major subprograms: the SPectroscopic IDentification of eROSITA Sources (SPIDERS), investigating X-ray AGNs. and galaxies in X-ray clusters, and the Time Domain Spectroscopic Survey (TDSS), obtaining spectra of variable sources. All programs use the 2.5 m Sloan Foundation Telescope at the. Apache Point Observatory; observations there began in Summer 2014. APOGEE-2 also operates a second near-infrared spectrograph at the 2.5 m du Pont Telescope at Las Campanas Observatory, with observations beginning in early 2017. Observations at both facilities are scheduled to continue through 2020. In keeping with previous SDSS policy, SDSS-IV provides regularly scheduled public data releases; the first one, Data Release 13, was made available in 2016 July.
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| 4. |
- Cui, Yong, et al.
(författare)
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Efficient Semitransparent Organic Solar Cells with Tunable Color enabled by an Ultralow-Bandgap Nonfullerene Acceptor
- 2017
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Ingår i: Advanced Materials. - : WILEY-V C H VERLAG GMBH. - 0935-9648 .- 1521-4095. ; 29:43
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Tidskriftsartikel (refereegranskat)abstract
- Semitransparent organic solar cells (OSCs) show attractive potential in power-generating windows. However, the development of semitransparent OSCs is lagging behind opaque OSCs. Here, an ultralow-bandgap non-fullerene acceptor, "IEICO-4Cl", is designed and synthesized, whose absorption spectrum is mainly located in the near-infrared region. When IEICO-4Cl is blended with different polymer donors (J52, PBDB-T, and PTB7-Th), the colors of the blend films can be tuned from purple to blue to cyan, respectively. Traditional OSCs with a nontransparent Al electrode fabricated by J52: IEICO-4Cl, PBDB-T: IEICO-4Cl, and PTB7-Th: IEICO-4Cl yield power conversion efficiencies (PCE) of 9.65 +/- 0.33%, 9.43 +/- 0.13%, and 10.0 +/- 0.2%, respectively. By using 15 nm Au as the electrode, semitransparent OSCs based on these three blends also show PCEs of 6.37%, 6.24%, and 6.97% with high average visible transmittance (AVT) of 35.1%, 35.7%, and 33.5%, respectively. Furthermore, via changing the thickness of Au in the OSCs, the relationship between the transmittance and efficiency is studied in detail, and an impressive PCE of 8.38% with an AVT of 25.7% is obtained, which is an outstanding value in the semitransparent OSCs.
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| 5. |
- Liu, Guofeng, et al.
(författare)
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Helicity Inversion of Supramolecular Hydrogels Induced by Achiral Substituents
- 2017
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 11:12, s. 11880-11889
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Tidskriftsartikel (refereegranskat)abstract
- Probing the supramolecular chirality of assemblies and controlling their handedness are closely related to the origin of chirality at the supramolecular level and the development of smart materials with desired handedness. However, it remains unclear how achiral residues covalently bonded to chiral amino acids can function in the chirality inversion of supramolecular assemblies. Herein, we report macroscopic chirality and dynamic manipulation of chiroptical activity of hydrogels self-assembled from phenylalanine derivatives, together with the inversion of their handedness achieved solely by exchanging achiral substituents between oligo(ethylene glycol) and carboxylic acid groups. This helicity inversion is mainly induced by distinct stacking mode of the self-assembled building blocks, as collectively confirmed by scanning electron microscopy, circular dichroism, crystallography, and molecular dynamics calculations. Through this straightforward approach, we were able to invert the handedness of helical assemblies by merely exchanging achiral substituents at the terminal of chiral gelators. This work not only presents a feasible strategy to achieve the handedness inversion of helical nanostructures for better understanding of chiral self-assembly process in supramolecular chemistry but also facilities the development of smart materials with controllable handedness in materials science.
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| 6. |
- Peng, Jianhui, et al.
(författare)
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Achieving ultra-high electromagnetic wave absorption by anchoring Co0.33Ni0.33Mn0.33Fe2O4 nanoparticles on graphene sheets using microwave-assisted polyol method
- 2018
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Ingår i: Ceramics International. - : ELSEVIER SCI LTD. - 0272-8842 .- 1873-3956. ; 44:17, s. 21015-21026
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Tidskriftsartikel (refereegranskat)abstract
- The Co0.33Ni0.33Mn0.33Fe2O4/graphene nanocomposite for electromagnetic wave absorption was successfully synthesized from metal chlorides solutions and graphite powder by a simple and rapid microwave-assisted polyol method via anchoring the Co0.33Ni0.33Mn0.33Fe2O4 nanoparticles on the layered graphene sheets. The Fe3+, Co2+, Ni2+ and Mn2+ ions in the solutions were attracted by graphene oxide obtained from graphite and converted to the precursors Fe(OH)(3), Co(OH)(2), Ni(OH)(2), and Mn(OH)(2) under slightly alkaline conditions. After the transformations of the precursors to Co-Ni-Mn ferrites and conversion of graphene oxide to graphene under microwave irradiation at 170 degrees C in just 25 min, the Co0.33Ni0.33Mn0.33Fe2O4/graphene nanocomposite was prepared. The composition and structure of the nanocomposite were characterized by X-ray diffraction (XRD), inductive coupled plasma emission spectroscopy (ICP), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy (RS), transmission electron microscopy (TEM), etc. It was found that with the filling ratio of only 20 wt% and the thickness of 2.3 mm, the nanocomposite showed an ultra-wide effective absorption bandwidth (less than -10 dB) of 8.48 GHz (from 9.52 to 18.00 GHz) with the minimum reflection loss of - 24.29 dB. Compared to pure graphene sheets, Co0.33Ni0.33Mn0.33Fe2O4 nano particles and the counterparts reported in literature, the nanocomposite exhibited much better electromagnetic wave absorption, mainly attributed to strong wave attenuation, as a result of synergistic effects of dielectric loss, conductive loss and magnetic loss, and to good impedance matching. In view of its thin thickness, light weight and outstanding electromagnetic wave absorption property, the nanocomposite could be used as a very promising electromagnetic wave absorber.
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