亚热带海岸沙地主要树种叶片金属元素含量与重吸收率

为了探讨不同树种对养分贫瘠环境的适应策略,以中国亚热带海岸沙地上5种主要树种(木麻黄Casuarina equisetifolia、厚荚相思Acacia crassicarpa、湿地松Pinus elliottii、尾巨桉Euca-lyptus grandis x E.urophylla和潺槁木姜子Litsea glu...     

赣南地热水形成条件分析与赣县区地热水勘查靶区圈定

为巩固脱贫攻坚成果,迈向乡村振兴,赣县人民梦寐以求在赣县探测到地热水资源.本文探讨了赣南山地隆起区构造裂隙地热水形成规律,分析了江西赣南地区地热水形成的条件:①燕山-喜山期岩浆侵入、热液活动是热供给来源;②红层盆地中巨厚的白垩系是储热盖层;③元古代至早古生代浅变质岩分布区岩石受多期次构造运动作用,裂隙发育、岩体破碎,有...     

Correction Factors of the Measurement Errors of the LAMOST-LRS Stellar Parameters

We aim to investigate the propriety of stellar parameter errors of the official data release of the LAMOST lowresolution spectroscopy(LRS) survey. We diagnose the errors of radial velocity(RV), atmospheric parameters([Fe/H], Teff, logg) and α-enhancement([α/M]) for the latest data release version of DR7, including 6,079,235effective spectra of 4,546,803 stars. Based on the duplicate observational sample and comparing the deviation of multiple measurements to their given errors, we find that, in ...     

Photometric Properties and Stellar Parameters of the Rapidly Rotating Magnetic Early-B Star HD 345439

We first present the multicolor photometry results of the rapidly rotating magnetic star HD 345439 using the Nanshan One-meter Wide-field Telescope.From the photometric observations,we derive a rotational period of 0.7699±0.0014 day.The light curves of HD 345439 are dominated by the double asymmetric S-wave feature that arises from the magnetic clouds.Pulsating behaviors are not observed in Sector 41 of the Transiting Exoplanet Survey Satellite.No evidence is found of the occurrence of centrifug...     

Results of 23 yr of Pulsar Timing of PSR J1453-6413

In this paper, we presented the 23.3 yr of pulsar timing results of PSR J1456-6413 based on the observations of Parkes 64 m radio telescope. We detected two new glitches at MJD 57093(3) and 59060(12) and confirmed its first glitch at MJD 54554(10). The relative sizes(Δν/ν) of these two new glitches are 0.9 × 10^-9and 1.16 × 10^-9,respectively. Using the “Cholesky” timing analysis method, we have determined its position, proper motion, and two-dimensional transverse velocities...     

An accessible strong-motion dataset (PGA,PGV, and site vS30) of 2022 MS6.8 Luding,China Earthquake

A M_S6.8 earthquake occurred on 5th September 2022 in Luding county, Sichuan, China, at 12: 52 Beijing Time(4:52 UTC). We complied a dataset of PGA, PGV, and site v_S30 of 73 accelerometers and 791 Micro-Electro-Mechanical System(MEMS)sensors within 300 km of the epicenter. The inferred v_S30 of 820 recording sites were validated. The study results show that:(1)The maximum horizontal PGA and PGV reaches 634.1 Gal and 71.1 cm/s respectively.(2) Over 80% of records ar...     

Neutral Hydrogen Content of Dwarf Galaxies in Different Environments

Environments play an important role in galaxy formation and evolution,particularly in regulating the content of neutral gas.However,current HI surveys have limitations in their depth,which prevents them from adequately studying low HI content galaxies in high-density regions.In this study,we address this issue by employing the Five-hundred-meter Aperture Spherical radio Telescope with extensive integration times to complement the relatively shallow Arecibo Legacy Fast Arecibo L-band Feed Array H...     

An Update of the Catalog of Radial Velocity Standard Stars from the APOGEE DR17

We present an updated catalog of 46,753 radial velocity(RV) standard stars selected from the APOGEE DR17.These stars cover the Northern and Southern Hemispheres almost evenly,with 62% being red giants and 38%being main sequence stars.These RV standard stars are stable on a baseline longer than 200 days(with 54% longer than one year and 10% longer than five years) with a median stability better than 215 m s^-1.The average number of observations of those stars is 5 and each observation i...     

Research on Ultra-wide Bandwidth Low-frequency Signal Channelization for Xinjiang 110m Radio Telescope

Aiming at the subband division of ultra-wide bandwidth low-frequency(UWL) signal(frequency coverage range:704–4032 MHz) of the Xinjiang 110 m QiTai radio Telescope(QTT), a scheme of ultra-wide bandwidth signal is designed. First, we analyze the effect of different window functions such as the Hanning window, Hamming window, and Kaiser window on the performance of finite impulse response(FIR) digital filters, and implement a critical sampling polyphase filter bank(CS-PFB) based on the Hamming win...     

DRC-Net Method for Two-dimensional Spectral Classification

Spectral classification plays a crucial role in the analysis of astronomical data. Currently, stellar spectral classification primarily relies on one-dimensional(1D) spectra and necessitates a sufficient signal-to-noise ratio(S/N). However, in cases where the S/N is low, obtaining valuable information becomes impractical. In this paper,we propose a novel model called DRC-Net(Double-branch celestial spectral classification network based on residual mechanisms) for stellar classification, which op...