The Large sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) general survey is a spectroscopic survey that will eventually cover approximately half of the celestial sphere and collect 10 million spectra of stars, galaxies and QSOs. Objects in both the pilot survey and the first year regular survey are included in the LAMOST DR1. The pilot survey started in October 2011 and ended in June 2012, and the data have been released to the public as the LAMOST Pilot Data Release in August 2012. The regular survey started in September 2012, and completed its first year of operation in June 2013. The LAMOST DR1 includes a total of 1202 plates containing 2 955 336 spectra, of which 1 790 879 spectra have observed signalto-noise ratio (SNR) ≥ 10. All data with SNR ≥ 2 are formally released as LAMOST DR1 under the LAMOST data policy. This data release contains a total of 2 204 696 spectra, of which 1 944 329 are stellar spectra, 12 082 are galaxy spectra and 5017 are quasars. The DR1 not only includes spectra, but also three stellar catalogs with measured parameters: late A,FGK-type stars with high quality spectra (1 061 918 entries), A-type stars (100 073 entries), and M-type stars (121 522 entries). This paper introduces the survey design, the observational and instrumental limitations, data reduction and analysis, and some caveats. A description of the FITS structure of spectral files and parameter catalogs is also provided.
Biomass burning (BB) is a primary source of brown carbon (BrC) in the atmosphere. In the present work, for the first time, the application of an impinger for BrC collection was investigated by conducting BB in a home-built setup. UV−vis, fluorescence, and IR measurements indicated that BrC samples collected by the impinger method have the same properties as those collected by the quartz filter method. In addition to exhibiting good BrC collection performance, the impinger was proven to be effective in concentrating methanolinsoluble substances from the smoke plume. Although elemental analysis and IR spectroscopy revealed that the insoluble substances were mainly composed of plant fibers, the fluorescence emission results showed the presence of BrC, and STEM analysis revealed that BrC was characterized by particles strung on wire-like plant fibers.
Chinese Low-rent housing subsidy has been increasing year by year. However, it will be a very one-sided view if we only take the increasing number of subsidy into consideration when evaluating the effects of subsidy policy on low-rent housing lessees. Thus we studied on the impact of subsidy increase on low-rent housing lessees' welfare in China, and explored a valid way to evaluate the utility of the subsidy policy. At first, basing on the theory of welfare, we analyze the indifference curve model within consumption budget condition. After that, we applied the Cobb–Douglas utility function to establish a low-rent housing lessees' welfare model. Finally, some suggestions, especially in regard to the use of Information Technology to support subsidy making and protect low-rent housing lessees' welfare, are given to the Ministry of Housing and Urban–Rural Development of the People's Republic of China (MOHURD) and local Municipal Commissions of Housing and Urban–Rural Development (MCOHURD).
Lightweight plays an important role in energy conservation and emission reduction. Foam injection molding (FIM) is a promising technology for the mass preparation of structural parts. But it is still a challenge to prepare foam with good cellular structure via low gas pressure foam injection molding (LGP-FIM). Polypropylene (PP) as a kind of universal plastic exhibits good mechanical properties, but its mechanical properties are notably deteriorated after foaming. In this study, ethylene-propylene-diene monomer (EPDM) rubber and high-density polyethylene (HDPE) were added to PP to improve its melt strength and increase the gas diffusion rate. As a result, the cell size of the ternary blend attained was ∼2 μm, and the cell density was increased to 10 10 cells/cm 3 . Meanwhile, the tensile toughness of ternary blend foam increased by 668% compared to PP foam. The notched impact strength of ternary blend foam increased by 178% compared to PP foam. Considering the excellent performance of PP foam and the low cost of LGP-FIM, this work presents a method for fabricating high mechanical performance foams that could be easily industrialized.
Organic–inorganic hybrid perovskites have attracted tremendous attention in the photovoltaic industry because of their low cost, simple production process, and high efficiency. However, (photo)stability is still one of the main problems that limits their development and enormous efforts have been made in this area. In this Review, we focus on the ubiquitous redox reactions in perovskite solar cells (PSCs), reveal the reasons behind the occurrence of the reactions (both external and internal factors) and the resulting effects (favorable and unfavorable), and collect methods to mitigate or block the occurrence of the reaction. Then, we summarize the means of characterizing redox reactions to visualize their presence and mechanisms. Finally, we envision future research directions in this field and consider redox reactions a double‐edged sword. We hope that these insights will contribute to accelerating the commercialization of PSCs.
External vibration, shock, unbalanced torque and other uncertain disturbances are mainly transmitted to the motor rotor through the bearing friction. To restrain the uncertain friction disturbances and improve the speed stability of a permanent magnet synchronous motor (PMSM), an optimized active disturbance rejection control (ADRC) algorithm is proposed in this study. Firstly, an auxiliary model of friction and a reduced-order processing method are introduced into extended state observation (ESO) to reduce the burden of single ESO and promote the compensation accuracy of disturbances. In addition, a supervisory radial basis function (SRBF) is employed to supervise and promote the error elimination efficiency of the nonlinear state error feedback rate (NLSEF). The hybrid control algorithm makes up for the deficiency of typical ADRC through the fusion of multiple control quantities. Simulation and experimental results show that the proposed algorithm has strong anti-disturbance performance and effectively solves the problem of low-speed crawling.
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