The atmospheric composition,extinction and luminosity of the LBV R71

ESO 3.6m Caspec spectra of the LMC luminous blue variable (LBV) taken at minimum have been analysed using NLTE model atmospheres and line formation calculations to derive atmospheric parameters and chemical composition. Using the silicon ionization balance and the hydrogen Balmer lines we deriveT _eff =17250, log g=1.80 and a microturbulent velocity of 15–20 km/s. The analysis yields abundance ratios by number of approximately 0.43 for He/H, 0.03 for C/N and 0.14 for O/N, implying that enrichment of the atmosphere by processed material has taken place. We have re-evaluated the reddening of R71 using IUE low resolution data and published UBVRIJHKL photometry and derive a value for A _V of 0.63. We also construct an extinction curve using archive IUE data for mid-B LMC supergiants and show that the extinction is anomalous; the 2175A bump being almost absent and the far UV rise very pronounced. A comparison of our model flux in theV-band with the observed (dereddened)V magnitude and the D.M. of the LMC (18.45), implies that the bolometric magnitude or R71 is –9.9. This is significantly higher than the value of –9.0 usually adopted for R71 and suggests that this object may not in fact be a subluminous LBV.     

G1000系统中GEA71部件及其常见故障分析

GEA71是G1000系统中一个非常重要的组件。本文简述了GEA71组件的安装位置和主要功用,并对其相关常见故障给出了排故思路。同时针对部分用户对GEA71组件出现误判的现象,还提供了Garmin公司给出的两条建议。     

智能远程温湿度监测系统的设计

介绍了一种通用的温湿度测量系统的设计,提出了以高集成度的温度湿度传感器SHT71作为数据采集模块,以MSP430F449为控制核心的多点测量系统的设计方案,该系统具有低成本、低功耗、高可靠性、抗干扰能力强等特点,根据不同需要可应用于多种温湿度检测系统中.