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The present study established a determination method of Psoraleae Fructus by quantitative analysis of multi-components by the single marker(QAMS) and further improved the thin-layer chromatography(TLC) method. The QAMS method was established by UPLC with psoralen as the internal marker, and the content of psoralenoside, isopsoralenoside, psoralen, and isopsoralen was simultaneously determined. As revealed by the comparison with results of the external standard method, the QAMS method was accurate and feasible. According to the current quality standards of Psoraleae Fructus, the TLC method was further optimized and improved, and bakuchiol was added for identification based on the original TLC method with psoralen and isopsoralen as indicators. This study provides a reference for improving the quality control method of Psoraleae Fructus.

Two new chroman-4-ones penicichromanone A (

With the great development of solar telescope, astronomers are always trying to achieve higher guiding precision, which is one of the most important technologies for the solar observation. At present, the most popular solar guiding depends on the imaging mapping, correlation procession and capture the solar image by CCD directly. In this paper, a new full disk solar guiding method based on post-focus lens obstruction are proposed. A simple structural modification has been used to improve our solar guiding measurement and even for other extended sources. It has been proved that our new method is correct and feasible after building a simulated experiment system and running lots of experiment tests.

The Multi-channel Photometric Survey Telescope (Mephisto) is a wide-field ground based telescope with a 1.6m primary mirror and 2° field of view, proposed by Yunnan University. The telescope will be capable of imaging the northern sky in three colors simultaneously and deliver a colored movie of the universe. The R-C system with lens corrector was adopted as the optical system considering of the image quality requirement, light obscuration and camera arrangement, in which three cubic splitters were adopted for the three channel beams in order to get satisfied image quality over the whole field of view. Dichroic coating on the cubic will lead to nonuniform efficiency on the focal plane due to the polarization problem and wide incident angle, which need calibration. The image quality represented in 80% encircled light energy is around 0.6arcsec. In order to keep the optimal image quality in any operational conditions, a 5-DOF mechanism was designed to actively adjust M2 mirror positions according to the wavefront sensors or by direct star psf. Now the telescope are under developing in Nanjing, expected to be installed at Lijiang observatory before the end of 2021.

Viral pneumonia is caused by a spreading of lung infection caused by respiratory viruses. Some virus infections were found to be highly aggressive, leading to lung inflammation and severe damage in respiratory system with high fatality rate. Currently, there is no effective therapeutic drugs in the clinic. The common clinical symptoms of viral pneumonias include fever, rhinitis, runny nose, nonproductive cough, fatigue, myalgias and headaches after the immune system being tricked by driving cytokines and overactivated immune response induced by cytokine storms. Patients with severe symptoms could get persistent high fever, dysfunctional breathing, consciousness disorders and even respiratory failure, post-inflammatory pulmonary fibrosis, multi-organ damages, shock and so on. Most clinical treatments are used to inhibit virus replication, relieve symptoms, inhibit excessive inflammatory response, regulate immune balance and protect organs. Both applied and basic research demonstrate that Chinese patent medicine has certain anti-viral effects, effectively inhibiting viral pneumonia transiting from mild to severe, rapid relieving of patient symptoms because of their multi-component and multi-target integrated roles. This review has summarized the reports on the treatment of viral pneumonia. Based on the pathogenic characteristics of viral pneumonia, this paper summarizes the diverse roles of the marketed Chinese patent medicine, such as their effects in inhibiting the progress of viral replication and overactivated inflammatory response, regulating immune balance, attenuating pulmonary fibrosis and so forth. Our paper summarizes the advantages of Chinese patient medicine in the treatment of viral pneumonia, based on which improvements of clinical therapy are expected to be made soon.

OPTICS is a density-based clustering method that can address point sets with different densities; however, the outlier detection capability of OPTICS is limited by several factors, such as different parameter and different point set shapes. Therefore, an outlier detection method based on OPTICS was proposed, known as OD-OPTICS, which adds a pre-processing process and modifies the CD computing method. First, the Radius Filtration Strategy, which provides the key radii, is performed; and the crucial distances of the point set are reflected. Then, for the purpose of filtrating invalid radii and selecting the most appropriate one, the Covering Space Model was proposed. With the influence of the three rules that we established, the basic distance between two neighbouring points can be calculated by the covering space. Moreover, the CD calculation was optimized such that it could magnify the difference value between normal points and outliers. In the experiment part, the pre-processing details were demonstrated and the validity of OD-OPTICS on public point sets were tested; to verify the optimization and detectability of OD-OPTICS, the proposed method is compared to OPTICS and four other typical methods. The results demonstrated that the detection performance of OD-OPTICS is superior to that of OPTICS.

The LAMOST spectral survey provides a rich databases for studying stellar spectroscopic properties and chromospheric activity. We cross-matched a total of 105,287 periodic variable stars from several photometric surveys and databases (CSS, LINEAR, Kepler, a recently updated eclipsing star catalogue, ASAS, NSVS, some part of SuperWASP survey, variable stars from the Tsinghua University-NAOC Transient Survey, and other objects from some new references) with four million stellar spectra published in the LAMOST data release 2 (DR2). We found 15,955 spectra for 11,469 stars (including 5398 eclipsing binaries). We calculated their equivalent widths (EWs) of their Hα, Hβ, Hγ, Hδ and Ca ii H lines. Using the Hα line EW, we found 447 spectra with emission above continuum for a total of 316 stars (178 eclipsing binaries). We identified 86 active stars (including 44 eclipsing binaries) with repeated LAMOST spectra. A total of 68 stars (including 34 eclipsing binaries) show chromospheric activity variability. We also found LAMOST spectra of 12 cataclysmic variables, five of which show chromospheric activity variability. We also made photometric follow-up studies of three short period targets (DY CVn, HAT-192-0001481, and LAMOST J164933.24+141255.0) using the Xinglong 60-cm telescope and the SARA 90-cm and 1-m telescopes, and obtained new BVRI CCD light curves. We analyzed these light curves and obtained orbital and starspot parameters. We detected the first flare event with a huge brightness increase of more than about 1.5 magnitudes in R filter in LAMOST J164933.24+141255.0.

We study the classification and composite spectra of galaxy in the fourth data release (DR4) of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST). We select 40,182 spectra of galaxies from LAMOST DR4, which have photometric in- formation but no spectroscopic observations in the Sloan Digital Sky Survey(SDSS). These newly observed spectra are re-calibrated and classified into six classes, i.e. pas- sive, H{\alpha}-weak, star-forming, composite, LINER and Seyfert using the line intensity (H\b{eta}, [OIII]{\lambda}5007, H{\alpha} and [NII]{\lambda}6585). We also study the correlation between spectral classes and morphological types through three parameters: concentration index, (u - r) color, and D4000n index. We calculate composite spectra of high signal-to-noise ra- tio(S/N) for six spectral classes, and using these composites we pick out some features that can differentiate the classes effectively, including H\b{eta}, Fe5015, H{\gamma}A, HK, and Mg2 band etc. In addition, we compare our composite spectra with the SDSS ones and analyse their difference. A galaxy catalogue of 40,182 newly observed spectra (36,601 targets) and the composite spectra of the six classes are available online., Comment: 14 pages, 11 figures

Full author list: J.-J. Ren, R. Raddi, A. Rebassa-Mansergas, M. S. Hernandez, S. G. Parsons, P. Irawati, P. Rittipruk, M. R. Schreiber, B. T. Gänsicke, S. Torres, H.-J. Wang, J.-B. Zhang, Y. Zhao, Y.-T. Zhou, Z.-W. Han, B. Wang, C. Liu, X.-W. Liu, Y. Wang, J. Zheng, J.-F. Wang, F. Zhao, K.-M. Cui, J.-R. Shi, and H. Tian, Close white dwarf binaries consisting of a white dwarf and an A-, F-, G-, or K-type main-sequence star, henceforth close WD+AFGK binaries, are ideal systems to understand the nature of type Ia supernovae progenitors and to test binary evolution models. In this work we identify 775 WD+AFGK candidates from TGAS (The Tycho-Gaia Astrometric Solution) and Gaia Data Release 2 (DR2), a well-defined sample of stars with available parallaxes, and we measure radial velocities (RVs) for 275 of them with the aim of identifying close binaries. The RVs have been measured from high-resolution spectra obtained at the Xinglong 2.16 m Telescope and the San Pedro Mártir 2.12 m Telescope and/or from available LAMOST DR6 (low-resolution) and RAVE DR5 (medium-resolution) spectra. We identify 23 WD+AFGK systems displaying more than 3σ RV variation among 151 systems for which the measured values are obtained from different nights. Our WD+AFGK binary sample contains both AFGK dwarfs and giants, with a giant fraction ∼43%. The close binary fractions we determine for the WD+AFGK dwarf and giant samples are ≃24% and ≃15%, respectively. We also determine the stellar parameters (i.e., effective temperature, surface gravity, metallicity, mass, and radius) of the AFGK companions with available high-resolution spectra. The stellar parameter distributions of the AFGK companions that are members of close and wide binary candidates do not show statistically significant differences., This work is partially supported by National Natural Science Foundation of China 11903048, 11833006, U1831209, and 11873057. R.R. has received funding from the postdoctoral fellowship program Beatriu de Pinós, funded by the Secretary of Universities and Research (Government of Catalonia) and by the Horizon 2020 program of research and innovation of the European Union under the Maria Skłodowska-Curie grant agreement No. 801370. A.R.M. acknowledges support from the MINECO under the Ramón y Cajal program (RYC-2016-20254) and the AYA2017-86274-P grant, and the AGAUR grant SGR661/2017. M.S.H. acknowledges support through a Fellowship for National PhD students from ANID, grant No. 21170070. S.G. P. acknowledges the support of the STFC Ernest Rutherford Fellowship. M.R.S. is thankful for support from FONDECYT (grant No. 1181404).

We have constructed a new timescale, TT(IPTA16), based on observations of radio pulsars presented in the first data release from the International Pulsar Timing Array (IPTA). We used two analysis techniques with independent estimates of the noise models for the pulsar observations and different algorithms for obtaining the pulsar timescale. The two analyses agree within the estimated uncertainties and both agree with TT(BIPM17), a post-corrected timescale produced by the Bureau International des Poids et Mesures (BIPM). We show that both methods could detect significant errors in TT(BIPM17) if they were present. We estimate the stability of the atomic clocks from which TT(BIPM17) is derived using observations of four rubidium fountain clocks at the US Naval Observatory. Comparing the power spectrum of TT(IPTA16) with that of these fountain clocks suggests that pulsar-based timescales are unlikely to contribute to the stability of the best timescales over the next decade, but they will remain a valuable independent check on atomic timescales. We also find that the stability of the pulsar-based timescale is likely to be limited by our knowledge of solar-system dynamics, and that errors in TT(BIPM17) will not be a limiting factor for the primary goal of the IPTA, which is to search for the signatures of nano-Hertz gravitational waves., Comment: accepted by MNRAS

Square Kilometre Array: et al., arXiv:1810.02680v3, The Square Kilometre Array (SKA) is a planned large radio interferometer designed to operate over a wide range of frequencies, and with an order of magnitude greater sensitivity and survey speed than any current radio telescope. The SKA will address many important topics in astronomy, ranging from planet formation to distant galaxies. However, in this work, we consider the perspective of the SKA as a facility for studying physics. We review four areas in which the SKA is expected to make major contributions to our understanding of fundamental physics: cosmic dawn and reionisation; gravity and gravitational radiation; cosmology and dark energy; and dark matter and astroparticle physics. These discussions demonstrate that the SKA will be a spectacular physics machine, which will provide many new breakthroughs and novel insights on matter, energy, and spacetime., A. Racanelli has received funding from the People Programme (Marie Curie Actions) of the European Union H2020 Programme under REA grant agreement number 706896 (COSMOFLAGS). Funding for this work was partially provided by the Spanish MINECO under MDM-2014-0369 of ICCUB (Unidad de Excelencia ‘Maria de Maeztu’).

Accurate determination of stellar atmospheric parameters and elemental abundances is crucial for Galactic archeology via large-scale spectroscopic surveys. In this paper, we estimate stellar atmospheric parameters -- effective temperature T_{\rm eff}, surface gravity log g and metallicity [Fe/H], absolute magnitudes M_V and M_{Ks}, {\alpha}-element to metal (and iron) abundance ratio [{\alpha}/M] (and [{\alpha}/Fe]), as well as carbon and nitrogen abundances [C/H] and [N/H] from the LAMOST spectra with amultivariate regressionmethod based on kernel-based principal component analysis, using stars in common with other surveys (Hipparcos, Kepler, APOGEE) as training data sets. Both internal and external examinations indicate that given a spectral signal-to-noise ratio (SNR) better than 50, our method is capable of delivering stellar parameters with a precision of ~100K for Teff, ~0.1 dex for log g, 0.3 -- 0.4mag for M_V and M_{Ks}, 0.1 dex for [Fe/H], [C/H] and [N/H], and better than 0.05 dex for [{\alpha}/M] ([{\alpha}/Fe]). The results are satisfactory even for a spectral SNR of 20. The work presents first determinations of [C/H] and [N/H] abundances from a vast data set of LAMOST, and, to our knowledge, the first reported implementation of absolute magnitude estimation directly based on the observed spectra. The derived stellar parameters for millions of stars from the LAMOST surveys will be publicly available in the form of value-added catalogues., Comment: 23 pages, 23 figures; MNRAS accepted

Big data obtained from a stellar spectroscopic survey carried out using the Large Sky Area Multi-object Fiber Spectroscopic Telescope (LAMOST, also known as Guo Shou Jing telescope) provide important information for studying chromospheric activity, variability of chromospheric activity, and chromospheric statistical properties, and for searching subdwarfs and extreme subdwarfs. Using as chromospheric activity indicator the line, we detected 6391 active M stars among the 99741 stars in the M-star catalogue of the LAMOST survey. We also obtained the relationship between the fraction of active stars and the spectral types, which is consistent to previous results. We also studied the effects of activity on broadband photometric colors, and we did not see significant differences between active and inactive M stars. Using as spectroscopic molecular indicators the CaH123 and TiO5 lines, we found 1288 subdwarfs (including 120 active subdwarfs). We also found 15 extreme subdwarf (2 active extreme subdwarf) candidates. Our subdwarf candidates are slightly redder by about 0.05 mag in g-r compared with dwarfs using the g-r and r-i, and g-r and i-z color diagrams. Using our active M-star catalogue, we found that 898 stars exhibited 140 emission in at least two exposures (170 of them in at least three exposures). Among these 170 stars, 163 of them show variability in H-alpha, emission on long timescales (more than 2.5 h). Furthermore, 34 stars show variability over short timescales (less than 2.5 h), and 29 actives show variability over both short and long time scales.

Real-time analysis of single-photon coincidence is critical in photonic quantum computing. The large channel number and high counting rate foreseen in such experiments pose a big challenge for the conventional time tagged method and coincidence instruments. Here we propose a real-time time-tagged coincidence method and a data filtering solution, demonstrated by a 32-channel coincidence counting unit that has been implemented successfully on a field-programmable gate array system. The unit provides high counting rates, a tunable coincidence window, and a timing resolution of 390 ps. Beyond that, it is feasible to be scaled up to 104 channels and is thus ideally suited for channel consuming applications such as boson sampling. Based on the versatility and scalability the unit has shown, we believe that it is the turn-key solution for many single-photon coincidence counting applications in photonic quantum computing.

Mechanism of conductive defect states based filament for MOM (metal/oxide/metal) resistive switching structures has been proposed. Emphasis is given on the point defects of silicon dangling bonds percolation model in oxide semiconductor Pt/SiO x /Pt structure devices and the conductive defects filament model of oxygen vacancies in ionic solids Ti/Al 2 O 3 /HfO 2 /Al 2 O 3 /Pt structure devices. We introduce the Mott’s 8-N rule bonding concept to help us to understand the creation and formation of defect states induced by material non-stoichiometry. The experimental results indicated that the conductive processes are based on migration (drift and diffusion) of both electrons and ions under the external electric field.

We analyse the stochastic properties of the 49 pulsars that comprise the first International Pulsar Timing Array (IPTA) data release. We use Bayesian methodology, performing model selection to determine the optimal description of the stochastic signals present in each pulsar. In addition to spin-noise and dispersion-measure (DM) variations, these models can include timing noise unique to a single observing system, or frequency band. We show the improved radio-frequency coverage and presence of overlapping data from different observing systems in the IPTA data set enables us to separate both system and band-dependent effects with much greater efficacy than in the individual PTA data sets. For example, we show that PSR J1643$-$1224 has, in addition to DM variations, significant band-dependent noise that is coherent between PTAs which we interpret as coming from time-variable scattering or refraction in the ionised interstellar medium. Failing to model these different contributions appropriately can dramatically alter the astrophysical interpretation of the stochastic signals observed in the residuals. In some cases, the spectral exponent of the spin noise signal can vary from 1.6 to 4 depending upon the model, which has direct implications for the long-term sensitivity of the pulsar to a stochastic gravitational-wave (GW) background. By using a more appropriate model, however, we can greatly improve a pulsar's sensitivity to GWs. For example, including system and band-dependent signals in the PSR J0437$-$4715 data set improves the upper limit on a fiducial GW background by $\sim 60\%$ compared to a model that includes DM variations and spin-noise only., Comment: 29 pages. 16 figures. Accepted for publication in MNRAS

The highly stable spin of neutron stars can be exploited for a variety of (astro-)physical investigations. In particular arrays of pulsars with rotational periods of the order of milliseconds can be used to detect correlated signals such as those caused by gravitational waves. Three such "Pulsar Timing Arrays" (PTAs) have been set up around the world over the past decades and collectively form the "International" PTA (IPTA). In this paper, we describe the first joint analysis of the data from the three regional PTAs, i.e. of the first IPTA data set. We describe the available PTA data, the approach presently followed for its combination and suggest improvements for future PTA research. Particular attention is paid to subtle details (such as underestimation of measurement uncertainty and long-period noise) that have often been ignored but which become important in this unprecedentedly large and inhomogeneous data set. We identify and describe in detail several factors that complicate IPTA research and provide recommendations for future pulsar timing efforts. The first IPTA data release presented here (and available online) is used to demonstrate the IPTA's potential of improving upon gravitational-wave limits placed by individual PTAs by a factor of ~2 and provides a 2-sigma limit on the dimensionless amplitude of a stochastic GWB of 1.7x10^{-15} at a frequency of 1 yr^{-1}. This is 1.7 times less constraining than the limit placed by (Shannon et al. 2015), due mostly to the more recent, high-quality data they used., 25 pages, 6 tables, 5 figures. Accepted for publication in MNRAS

Here we present a catalogue of 1056 spectroscopically identified hydrogen-dominated white dwarfs (DAWDs), 34 helium-dominated white dwarfs (DBWDs) and 276 white dwarf main sequence (WDMS) binaries from the Large sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) survey data release 2 (DR2). 383 DAWDs, 4 DBWDs and 138 WDMSs are new identifications after cross-match with literature. There are similar to 4100 k spectra in total from DR 2. The low ratio of white dwarfs found in LAMOST is attributed to biased selection of LAMOST input catalogue and much brighter targets relative to stars observed in Sloan Digital Sky Survey. In this paper, a new DAWD selection method is adopted as a new attempt and supplement to the traditional methods. The effective temperature, surface gravity, mass, cooling age and distance of high signal-to-noise DAWDs are estimated. The peak of the mass distribution is found to be similar to 0.6 M-circle dot, which is consistent with previous work. The parameters of WDMS binaries are also provided in this paper. As the foundation of our future work, which is to identify more WDs with debris disc, WDs found in LAMOST showed a lot of potential. Interesting infrared-excess WDs will be reported in our forthcoming paper.

In this work, we select spectra of stars with high signal-to-noise ratio from LAMOST data and map their MK classes to the spectral features. The equivalent widths of prominent spectral lines, which play a similar role as multi-color photometry, form a clean stellar locus well ordered by MK classes. The advantage of the stellar locus in line indices is that it gives a natural and continuous classification of stars consistent with either broadly used MK classes or stellar astrophysical parameters. We also employ an SVM-based classification algorithm to assign MK classes to LAMOST stellar spectra. We find that the completenesses of the classifications are up to 90% for A and G type stars, but they are down to about 50% for OB and K type stars. About 40% of the OB and K type stars are mis-classified as A and G type stars, respectively. This is likely due to the difference in the spectral features between late B type and early A type stars or between late G and early K type stars being very weak. The relatively poor performance of the automatic MK classification with SVM suggests that the direct use of line indices to classify stars is likely a more preferable choice.

In this work, we report new quasars discovered in fields in the vicinity of the Andromeda (M31) and Triangulum (M33) galaxies with the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST, also called the Guo Shou Jing Telescope) during the 2013 observational season, the second year of the regular survey. In total, 1330 new quasars are discovered in an area of ～ 133 deg 2 around M31 and M33. With i magnitudes ranging from 14.79 to 20.0 and redshifts from 0.08 to 4.85, the 1330 new quasars represent a significant increase in the number of identified quasars in fields in the vicinity of M31 and M33. Up to now, there have been a total of 1870 quasars discovered by LAMOST in this area. The much enlarged sample of known quasars in this area can potentially be utilized to construct a precise astrometric reference frame for the measurement of minute proper motions of M31, M33 and their associated substructures, which are vital for understanding the formation and evolution of M31, M33 and the Local Group of galaxies. Moreover, in the sample, there are a total of 45, 98 and 225 quasars with i magnitudes brighter than 17.0, 17.5 and 18.0 respectively. In the aforementioned brightness bins, 15, 35 and 84 quasars are reported here for the first time, and 6, 21 and 81 are reported in our pervious work. In addition, 0, 1 and 6 are from the Sloan Digital Sky Survey and 24, 41 and 54 are from the NED database. These bright quasars provide an invaluable sample to study the kinematics and chemistry of the interstellar/intergalactic medium of the Local Group.

In this work, we provide 2189 photometrically- and kinematically-selected candidate members of 24 star clusters from the LAMOST DR2 catalog. We perform two-step membership identification: selection along the stellar track in the color-magnitude diagram, i.e., photometric identification, and selection from the distribution of radial velocities, i.e. the kinematic identification. We find that the radial velocities from the LAMOST data are very helpful in the membership identification. The mean probability of membership is 40% for the sample selected with radial velocity. With these 24 star clusters, we investigate the performance of the radial velocity and metallicity estimated with the LAMOST pipeline. We find that the systematic offsets in radial velocity and metallicity are 0.85 ± 1.26 km s −1 and −0.08 ± 0.04 dex, with dispersions of 5.47 +1.16 −0.71 km s −1 and 0.13 +0.04 −0.02 dex, respectively. Finally, we propose that the photometrically-selected candidate members of the clusters covered by the LAMOST footprint should be assigned higher priority so that more candidate stars can be observed.

Hypervelocity stars are believed to be ejected out from the Galactic center through dynamical interactions between (binary) stars and the central supermassive black hole(s). In this paper, we report 19 low mass F/G/K type hypervelocity star candidates from over one million stars found in the first data release of the LAMOST regular survey. We determine the unbound probability for each candidate using a Monte-Carlo simulation by assuming a non-Gaussian proper-motion error distribution, and Gaussian heliocentric distance and radial velocity error distributions. The simulation results show that all the candidates have unbound possibilities over 50% as expected, and one of them may even exceed escape velocity with over 90% probability. In addition, we compare the metallicities of our candidates with the metallicity distribution functions of the Galactic bulge, disk, halo and globular clusters, and conclude that the Galactic bulge or disk is likely the birth place for our candidates.

We have compared stellar parameters, including temperature, gravity and metallicity, for common stars in the LAMOST DR2 and SDSS DR12/APOGEE datasets. It is found that the LAMOST dataset provides a more well-defined red clump feature than the APOGEE dataset in the T eff versus log g diagram. With this advantage, we have separated red clump stars from red giant stars, and attempt to establish calibrations between the two datasets for the two groups of stars. The results show that there is a good consistency in temperature with a calibration close to the one-to-one line, and we can establish a satisfactory metallicity calibration of [Fe/H] APOGEE = 1.18[Fe/H] LAMOST + 0.11 with a scatter of ~ 0.08 dex for both the red clump and red giant branch samples. For gravity, there is no correlation for red clump stars between the two datasets, and scatters around the calibrations of red giant stars are substantial. We found two main sources of scatter in log g for red giant stars. One is a group of stars with 0.00253 × T eff − 8.67 −1 and log g APOGEE = 0.000874× T eff,LAMOST +0.588×log g LAMOST −3.117 (σ = 0.167) for [Fe/H] < −1. The calibrations are valid for stars with T eff = 3800 − 5400 K and log g = 0 − 3.8 dex, and are useful in work aiming to combine the LAMOST and APOGEE datasets in a future study. In addition, we find that an SVM method based on asteroseismic log g is a good way to greatly improve the accuracy of gravity for these two regions, at least in the LAMOST dataset.

We present chromospheric activity index S HK measurements for 119 995 F, G and K stars with high signal-to-noise ratio (S/N > 80) spectra, extracted from LAMOST DR1 in SDSS g band. The index δS for each of these stars is calculated by the difference between its S HK value and the baseline determined from very inactive stars. The effect of metallicity on measurement of δS varies with stellar T eff . No evident Vaughan-Preston gap appears in our sample. The relation between δS and vertical distance from the Galactic plane is determined for stars with T eff 5500 K, similar δS levels appear in both young and old cluster stars, which supports Pace’s suggestion that caution should be exercised when deriving the age of a single star by using its chromospheric activity. Finally, we investigate the relation between δS and the kinematics of our sample.

We present a catalog of 908 objects observed with the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) in fields in the vicinity of M31 and M33, targeted as globular clusters (GCs) and candidates. The targets include known GCs and candidates selected from the literature, as well as new candidates selected from the Sloan Digital Sky Survey (SDSS). Analysis shows that 356 of them are likely GCs with various confidence levels, while the remaining ones turn out to be background galaxies and quasars, stars and H II regions in M31 or foreground Galactic stars. The 356 likely GCs include 298 bona fide GCs and 26 candidates known in the literature. Three candidates, selected from the Revised Bologna Catalog of M31 GCs and candidates (RBC) and one possible cluster from Johnson et al., are confirmed to be bona fide clusters. We search for new GCs in the halo of the M31 among the new candidates selected from the SDSS photometry. Based on radial velocities yielded by LAMOST spectra and visual examination of the SDSS images, we find 28 objects, 5 bona fide and 23 likely GCs. Among the five bona fide GCs, three have been recently discovered independently by others, and the remaining 25 are our new identifications, including two bona fide ones. The newly identified objects fall at projected distances ranging from 13 to 265 kpc from M31. Of the two newly discovered bona fide GCs, one is located near M33, probably a GC belonging to M33. The other bona fide GC falls on the Giant Stream with a projected distance of 78 kpc from M31. Of the 23 newly identified likely GCs, one has a projected distance of about 265 kpc from M31 and could be an intergalactic cluster.

Most Galactic metal-poor stars exhibit enhanced α-abundances (e.g. [Mg/Fe] ~ +0.4) according to previous studies of stellar chemical compositions. However, a handful of metal-poor stars with large deficiencies in Mg (e.g. [Mg/Fe] ~ −0.2) show severe departures from this α-enhancement trend. The sub-solar [Mg/Fe] ratios of these anomalous stars indicate that they possess different chemical enrichment histories than the majority of Galactic metal-poor stars. In previous work, we presented a method to select Mg-poor metal-poor stars from low-resolution SDSS spectra based on a spectral matching technique. In this paper, a similar method is applied to low-resolution ( R ~ 1800) LAMOST spectra. Stellar [Mg/Fe] abundances are determined by using stellar parameters delivered by the LAMOST Data Release 2 catalog. From a sample of ~ 60 000 stars with atmospheric parameters in the range T eff = [5500, 6500] K and [Fe/H] = [−2.4, +0.5], we select 15 candidate Mg-poor metal-poor stars.

We present a spectroscopic catalog of 93 619 M dwarfs from the first data release of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) general survey. During sample selection, M giant contamination was eliminated using 2MASS photometry and CaH/TiO molecular indices. For each spectrum, the spectral subtype and values are provided including radial velocity, Hα equivalent width, a series of prominent molecular band indices, and the metal–sensitive parameter ζ, as well as distances and the space motions for high S/N objects. In addition, Hα emission lines are measured to examine the magnetic activity properties of M dwarfs and 7179 active ones are found. In particular, a subsample with significant variation in magnetic activity is revealed through observations from different epochs. Finally, statistical analysis for this sample is performed, including the metallicity classification, the distribution of molecular band indices and their errors.

Stellar fundamental parameters are important in the asteroseismic study of Kepler light curves. However, the most used estimates in the Kepler Input Catalog (KIC) are not accurate enough for hot stars. Using a sample of B stars from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) spectral survey, we confirmed the systematic underestimation in KIC effective temperature and overestimation in KIC surface gravity. The good agreement between LAMOST and other follow-up observations proved the accuracy of effective temperature and surface gravity of B stars derived from LAMOST low-resolution spectra. By searching through LAMOST data, we found four misclassified main-sequence B stars in the Kepler field, which had been previously classified as A-type variables. We present spectroscopic and detailed frequency analysis of these four stars based on LAMOST spectra and Kepler photometry., 19 pages, 12 figures, 7 tables, to appear in ApJ

We study the metallicity distribution and kinematic properties of 4,680 A/F/G/K-type giant stars with $|z|>$ 5 kpc selected from the LAMOST spectroscopic survey. The metallicity distribution of giant stars with 5 $, Comment: 8 pages, 8 figures, accepted for publication in ApJ

The radial number density and flattening of the Milky Way's stellar halo is measured with $\mathrm{5351}$ metal-poor ([Fe/H]$, Comment: 16 pages, 24 figures, accepted by MNRAS

Orthogonal experiments on oil content are done on a test rig in our lab by ECT (electrical capacitance tomography) technology under different experiment data groups which includes 3 kinds of characteristic parameters, such as air pressures, oil volume-per-cycle and lubrication cycle, of the system. The influence degree of the three characteristic parameters on oil content is sorted, and then the optimum experimental conditions resulted in the smallest oil content and the most stable distribution of oil film are obtained respectively from the experiments, and finally the change trend of the effect of lubrication cycle on the oil content is got by changing lubrication cycle, one of the 3 characteristic parameters, at a time and keeping 2 left characteristic parameters at the best level above proposed. These results will help us to research and apply further in the oil–air lubrication system.

Thickness of oil film, a parameter of an oil-air lubrication system, is an important evaluation criterion for two-phase annular flow flowed in the system. Experiment of the effects of oil volume-per-cycle on oil film’s thickness is done on a special test rig using ECT technology, and then the changing rule of oil film’s thickness is analyzed in this paper. The results show that, at the first the thickness of oil film is thinness and weakness, and then it changes to thickness and stabilization, at the last the oil focusing on the bottom of tube. The break of annular flow and the blocking of oil at elbow tube have been studied experimentally and theoretically.

Along with the development of society and economy, researchers begin to focus on the quality of economic development from simple pursuing economic growth rate. There are many indexes to measure the economic development quality, and carbon efficiency is one of the most important indexes. This paper constructing DEA model to calculate carbon efficiency indexes directly, through the carbon efficiency evaluation, can reflect the quality of economic growth objectively and then provide scientific basis for relevant government departments to make environmental economic decisions. Therefore, this study selects the four provincial-level municipalities of China (Beijing, Shanghai, Tianjin and Chongqing) as a case to evaluate carbon efficiency.

The resistive switching behaviors are investigated in highly silicon-rich SiOx (x = 0.73) films, which are deposited using the plasma enhanced chemical vapor deposition method. For the Pt/SiO0.73/Pt structures, after the forming process the reset voltages (∼0.7 V) are lower than the set voltages (∼1.7 V). The metal-free structures N+-Si/SiO0.73/N++-Si/Pt show almost the same switching behaviors as those of Pt/SiO0.73/Pt structures, demonstrating an intrinsic resistive switching mechanism. We use the silicon dangling bonds (Si-DBs) percolation model to explain this. It is based on the biasing electric field decreasing the bond strength and leading to the breakage of Si–O bonds in SiOx films. Consequently the new Si-DBs are created and will contribute to form the dangling bonds percolation path. The temperature dependence of forming voltages is investigated. The forming voltages show no obvious changes and the forming process will occur as soon as the sweeping voltage reaches ∼10.5 V, even if the temperature decreases to 5.5 K. It indicates that the electric field plays an important role during the forming processes. Moreover, through the analysis of X-ray photoelectron spectroscopy and electron spin resonance signals, it can be concluded that the •Si≡Si3 and •Si≡Si2O DBs centers are the main components in Si-DBs percolation path of SiO0.73 films.

the green design appeared in the 1980 s, this paper mainly introduces the concept of green design, features, basic principles of design, and the method of green design and the development trend of green packaging in our country. From the perspective of protecting the environment and resources, I put forward the significance of developing green packaging design and point out how to develop and perfect the green packaging design in our country based on analysis.

In physics experiments, various modular electronic instruments are developed in custom chassis, where several modules communicate and work jointly through a backplane. For maintaining the normal operation of these instruments, it is always necessary to fulfill routine management tasks on the modules. In this paper, we realize a JTAG-based modular instrument management bus on the backplane, with which the modules can be efficiently managed in batches. This management bus is built in a single-ring daisy-chain architecture and offers excellent compatibility with relevant hardware and software from different FPGA manufacturers. For surmounting the main disadvantage of this single-ring daisy chain, we designed a new automatic-check module integrated in the bus, based on which the communication between the modules on the backplane can be retained with empty slots in the chain. In addition, this bus is capable of being applied to different backplane infrastructures as long as they support the standard JTAG protocol. Based on these designs, our management bus can raise the working efficiency of custom scientific modular instruments.

Many novel and promising single-photon avalanche diodes (SPADs) emerged in recent years. However, some of them may demonstrate a very high dark count rate, even tens of megahertz, especially during the development phase or at room temperature, posing new challenges to device characterization. Gating operation with a width of 10 ns can be used to suppress the dark counts not coincident with the photon arriving time. However, as a side effect of the fast-gating operation, the gating response could be much higher than the avalanche signal and is usually removed by various circuit-based cancellation techniques. Here, we present an alternative method. A high-speed digital storage oscilloscope (DSO) is used to extract the weak avalanche signals from the large gating response background by waveform subtraction in software. Consequently, no complex circuit and precise tuning for each SPAD are needed. The avalanche detection threshold can be reduced to 5% of the full vertical scale of the DSO or 5 mV, whichever is greater. The timing resolution can be better than 2 ps for typical avalanche signals. Optical alignment and calibration are easy. The feasibility of on-wafer test with an RF probe station is discussed. All the advantages and features listed above make this method very useful in new SPAD research.

The aim of the present study was to investigate the role of interleukin (IL)-21 in chronic hepatitis B virus (HBV) infection. IL-21 stimulates T and B cell responses and plays a role in the control of chronic viral infections. Serum IL-21 levels were measured by enzyme immunoassay in 109 patients with chronic HBV infection at various clinical stages, as well as in 19 healthy controls (HCs). The proportion of T cells producing IL-21 in the peripheral blood was assessed by intracellular cytokine staining and flow cytometry. Mean serum IL-21 levels in patients with chronic hepatitis B (CHB) and the HCs were 303.54±152.77 pg/ml and 68.24±9.06 pg/ml, respectively (P=0.003). In addition, the mean serum IL-21 level in patients with hepatitis B-related acute-on-chronic liver failure (HB-ACLF) was 455.38±412.38 pg/ml, which exhibited a statistically significant difference when compared with the HCs (P=0.000). Serum IL-21 levels were highest in the patients with HB-ACLF (455.38±412.38 pg/ml) and exhibited a significant difference when compared with the CHB patients (P=0.04). The mean serum IL-21 levels in patients with cirrhosis also increased, but there was no statistically significant difference when compared with the HCs (P=0.82). The frequency of IL-21+CD4+ cells also increased compared with the HCs and correlated with the number and percentage of lymphocytes in the peripheral blood. Serum IL-21 levels increased in CHB and HB-ACLF patients. Relatively low serum IL-21 levels in CHB may have a causal role in the persistence of HBV infection. Higher serum levels in HB-ACLF may activate T and B cells to eliminate the virus or injure the liver via the release of inflammatory cytokines.

Hemorrhagic fever with renal syndrome (HFRS) is an acute viral infection caused by Hantavirus (HTV). Capillary leakage is one of the hallmarks of HTV infection. The mechanisms underlying the pathogenesis of HFRS are not completely understood. However, it has been suggested that immune mechanisms, including cytokines, might have an important role in HFRS pathogenesis. In this study, we investigated the potential role of interleukin-21 (IL-21) which is a newly discovered cytokine that stimulates T-cell and B-cell responses in the pathogenesis of HFRS. Serum samples were collected from 58 patients hospitalized with laboratory-verified HTV infection and 20 healthy controls. Serum IL-21 concentration was measured using an enzyme-linked immunosorbent assay. Serum IL-21 levels began to increase in the fever phase when renal damage appeared. The highest serum IL-21 level was detected in oliguric phase along with the peak degree of urinary renal impairment. When entering the polyuric phase, with gradual increase in urine and recovered renal function, the serum IL-21 level was observed to fall, returning to normal level after the renal function recovered in the convalescent phase. The serum IL-21 level was positively correlated with blood urea nitrogen (BUN) and creatinine (Cr), suggesting that the serum IL-21 level is associated with the disease severity of HFRS. This study indicated that IL-21 may act as an important inflammatory mediator in the immunopathogenesis of HFRS. The strategy to control IL-21 may hamper the immune response in patients with HFRS.

The fluid domain model of a new oil-air distributor in oil-air lubrication system is built and the phase distribution of oil and air two-phase flow on distribution interface is simulated based on the CFD model in Fluent, the mass flow rate of oil and air are collected from three different cross sections when the structures of oil-air guidance slot are designed as a plane, sphere and cone shape respectively, then the influence of oil-air guidance slot structure on the performance of distributor is analyzed in the oil-air lubrication system in this paper. The results show that the spherical surface and conical surface of oil-air guidance slot can improve the uniformity and stability of the oil and air two-phase flow distribution, promote the flow pattern to form a continuous annular oil film. Among these three structures of oil-air guidance slot, we also find that the distribution performance of conical surface is the best.

Speed of rolling bearing and flow rate of air have important influences on the bearing’s working temperature under the oil-air lubrication mode. Based on basic principle of lubrication, one of the heat productivity equations of deep groove ball bearing is selected to calculate the heat value of bearing’s cavity. The bearing’s temperature field is simulated by Fluent at different rotational speeds and air flow rates. Results of the simulation show that the highest temperatures of bearing have a quantitative relationship with the bearing’s rotational speeds. The relationships between the velocity of inlet and heat transfer coefficient, viscosity of the lubricant and the heating of bearing are analyzed in the end of this paper.

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