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.

Despite tremendous progress in optoelectronic devices using lead perovskite (CH3NH3(+)PbI3(-)), there has been a paucity of mechanistic information on how photoactive micron-sized crystals of lead perovskite grow from a mixture of a layered crystal of lead(II) iodide and methylammonium iodide mediated by a polar solvent, DMSO or DMF. We report here that the whole process of the lead perovskite synthesis consists of a series of equilibria driven by reversible solvent participation involving a polymeric strip of plumbate(II) oligomer as a key intermediate. A significant finding includes quick decomposition of perovskite crystal upon exposure to DMSO or DMF at room temperature, where the solvent molecules act as a base to remove acidic ammonium iodide from the perovskite crystal. This observation accounts for the difficulty in controlling perovskite solar cell fabrication. Overall, the polar solvent is indispensible first to degrade a 2-D sheet of crystals of lead(II) iodide into 1-D fibrous intermediates and then to promote Oswald ripening of perovskite crystals. The detailed chemical information provided here will help to rationalize the photovoltaic device studies that have so far remained empirical and to open a new venue to a developing field of microscale lead perovskite devices, as illustrated by fabrication of photovoltaic devices and photodetectors.

Stable perovskite CH3NH3PbI3-xClx for a photodetector was prepared through spin-coating of a fluorous polymer as a light protection layer. The best responsivity of photodetector was 14.5 A/W to white light and 7.85 A/W for solar-blind UV light (λ = 254 nm). The response time was in the submicrosecond range. The fluorous polymer coating increases the lifetime of the devices to almost 100 days.

The approach of a hydrophilic group grafted buffer layer (HGGBL) was investigated for perovskite growth to realize highly efficient inverted planar perovskite solar cells with superior reproducibility, negligible hysteresis and improved stability.

Viscoelasticity-induced particle migration has recently received increasing attention due to its ability to obtain high-quality focusing over a wide range of flow rates. However, its application is limited to low throughput regime since the particles can defocus as flow rate increases. Using an engineered carrier medium with constant and low viscosity and strong elasticity, the sample flow rates are improved to be one order of magnitude higher than those in existing studies. Utilizing differential focusing of particles of different sizes, here we present sheathless particle/cell separation in simple straight microchannels that possess excellent parallelizability for further throughput enhancement. The present method can be implemented over a wide range of particle/cell sizes and flow rates. We successfully separate small particles from larger particles, MCF-7 cells from red blood cells (RBCs), and Escherichia coli (E. coli) bacteria from RBCs in different straight microchannels. The proposed method could broaden the applications of viscoelastic microfluidic devices to particle/cell separation due to the enhanced sample throughput and simple channel design.Continuous manipulation and separation of particles and cells is important for a wide range of applications in biology, 1,2 medicine, 2,3 and industry. [4][5][6] Microfluidic systems have been proven to be promising tools for particle/cell manipulation with higher sensitivity and accuracy than their macroscale counterparts. The last decade has seen extensive development of microfluidic approaches for particle/cell manipulation that resort to immunocapture, 7 externally applied physical fields, [8][9][10][11][12][13][14][15][16][17][18] microfiltration, 19,20 gravitational sedimentation, 21 or deterministic lateral migration. 22,23 More recently, cross-streamline migration induced by the hydrodynamic effects of carrier media, such as inertia 24,25 and viscoelasticity, 26,27 has shown its promise for effective particle/cell manipulation without need of labeling and external force fields. Particles and cells can be separated based on the size-dependent nature of hydrodynamic forces. Briefly, the inertial lift scales as F a ∝ , where a is the particle diameter. There are several cell types of biological and clinical interest with separable size ranges: epithelial tumor cells (15-25 µm in diameter), blood cells (erythrocytes are 6-8 µm biconcave disks and peripheral blood lymphocytes are 7-10 µm in diameter), and bacteria (1-3 µm). Inertial migration in Newtonian fluids has been intensively studied and implemented in high-throughput label-free separation devices for cell separation. [28][29][30][31][32][33][34] Recently, particle migration induced by viscoelasticity has begun to attract increasing attention due to its simple focusing pattern and potential for achieving efficient focusing over a wide range of flow rates. 35,36 In a viscoelastic medium, elasticity coupled with non-negligible inertia will drive particles towards the channel centerline, whic...

The structure of nanoparticles plays a critical role in dictating their material properties. Gold is well known to adopt face-centered cubic (fcc) structure. Herein we report the first observation of a body-centered cubic (bcc) gold nanocluster composed of 38 gold atoms protected by 20 adamantanethiolate ligands and two sulfido atoms ([Au38S2(SR)20], where R=C10H15) as revealed by single-crystal X-ray crystallography. This bcc structure is in striking contrast with the fcc structure of bulk gold and conventional Au nanoparticles, as well as the bi-icosahedral structure of [Au38(SCH2CH2Ph)24]. The bcc nanocluster has a distinct HOMO-LUMO gap of ca. 1.5 eV, much larger than the gap (0.9 eV) of the bi-icosahedral [Au38(SCH2CH2Ph)24]. The unique structure of the bcc gold nanocluster may be promising in catalytic applications.

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We find that Galactic disk stars near the anticenter exhibit velocity asymmetries in both the Galactocentric radial and vertical components across the mid-plane as well as azimuthally. These findings are based on LAMOST spectroscopic velocities for a sample of ∼ 400, 000 F-type stars, combined with proper motions from the PPMXL catalog for which we have derived corrections to the zero points based in part on spectroscopically discovered galaxies and QSOs from LAMOST. In the region within 2 kpc outside the Sun's radius and ±2 kpc from the Galactic midplane, we show that stars above the plane exhibit net outward radial motions with downward vertical velocities, while stars below the plane have roughly the opposite behavior. We discuss this in the context of other recent findings, and conclude that we are likely seeing the signature of vertical disturbances to the disk due to an external perturbation.