Implementation of New OPAL Tables in Eggleton's Stellar Evolution Code

Based on previous works of OPAL, we construct a series of opacity tables for various metallicities Z=0, 0.000 01, 0.000 03, 0.000 1, 0.000 3, 0.001, 0.004, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.08 and 0.1. These tables can be easily used in Eggleton's stellar evolution code in place of the old tables without changing the code. The OPAL tables are used for log10(T/K) > 3.95 and Alexander's for log10(T/K) < 3.95. At log10(T/K) = 3.95, the two groups' data fit well for all hydrogen mass fractions. Conductive opacities are included by reciprocal addition according to the formulae of Yakovlev and Urpin. A comparison of 1 and 5 M models constructed with the older OPAL tables of Iglesias and Rogers shows that the new opacities have most effect in the late stages of evolution, the extension of the blue loop during helium burning for intermediate-mass and massive stars.     

SMALL项目数字化地磁资料可靠性分析

在对中美合作 SMALL (中国低纬地磁台阵 )项目安装在北京地磁台 (白家疃 )和云南通海地磁台的磁通门磁力仪记录资料与磁变仪模拟记录资料进行了详细的对比分析后 ,得出的结果表明 ,两者的日变形态、日变幅有较好的一致性 ,所选特定事件的变化幅度非常一致 ,说明磁通门磁力仪记录到的变化磁场的资料是真实可靠的。尽管目前磁通门磁力仪的基线值存在温度影响和离散度较大的问题 ,但随温度变化有明显的规律性 ,若能采取改进观测条件和观测方法以及缩短观测时间等措施 ,并对基线值进温度校正 ,磁通门磁力仪完全可以提供长期连续可靠的资料。而其为地震预报 ,空间环境预报 ,为日地物理 ,空间物理和地磁学的研究提供的高精度、高分辨率、连续可靠的数字化变化磁场资料是磁变仪模拟记录无法比拟的。     

断层模型在火山区形变和重力反演中的应用

利用腾冲火山区1998～2002年的垂直形变和重力测量资料，应用多元Mogi模型对测区的等效岩浆房位置及大小进行了反演计算，得出了最佳拟合值。但当对形变和重力资料联合分析时却发现：实测重力数据比用球形Mogi模型计算所得的值要大得多。为了对此进行合理的解释，提出了断层模型。当岩浆沿断层上升时，充填了断层中原先存在的大量空隙．因而可以只对重力产生影响．而不对形变产生影响。为此沿断层积分得出上升岩浆所产生的重力异常，其结果与实测重力资料拟合得较好。同时断层模型也对负的岩浆源(即岩浆的流失)作出了较为合理的解释。     

Coping with Pressures of Modernization by Traditional Farmers： a Strategy for Sustainable Rural Development in Yunnan, China

Traditional farming practices conform to sustainable rural livelihoods, while agricultural modernisation tends to undermine these practices through various perturbations. A case study in Tengchong County (western Yunnan, China) shows that transformation of traditional alder (Alnus nepalensis) and dry rice (upland rice) rotational farming to introduced Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) plantations leads to localised water scarcity and soil fertility decline. While farmers are aware of ecological sustainability of traditional farming, they prefer Chinese fir forestry because it is less labour-intensive, has a high market value, and releases time for profitable off-farm work. Farmers adapt to economic liberalization by planting high value crops and trees. However, alternatives to make local agricultural production more profitable through competitive business strategies, cooperative approaches, innovations in integrating high value crops and 'downstream' processingfor sustainable rural livelihoods have been overlooked largely due to poor information availability and lack of organisational framework.     

紫金山天文台13.7米望远镜水脉泽观测星表

本文简要总结了自1990年8月至1994年1日在紫金山天文台13.7米射电望远镜上进行的水脉泽源的观测,观测结果汇集为表1和图1。在所有435个观测对象中共观测到195个水脉泽源,其中108个为新探测到的 本文对观测仪器和数据处理亦作了简要介绍。     

Optical Photometric Observations of 7-Ray Loud Blazars

We report results of our optical photometric observations of ten gamma-ray loud blazers, namely: 0219+428 (3C66A), PKS 0420-014 (OA 129), S5 0716+714, 0754+100 (OI 090.4), 0827+243 (OJ248), 1652+398 (Mrk 501), 2200+420 (BL Lacertae), 2230+114 (CTA 102), 2251+158 (3C 454.3) and 2344+514. The observations were carried out in September-October, 2000 using the 70 cm optical telescope at Abstumani Observatory, Georgia. We found intra-day variations in 0420-014, S5 0716+714, BL Lacertae and CTA 102. A variation of 0.3 magnitude over a time scale of about 3 hours was observed in the R passband in BL Lacertae on JD 2451827. We did not detect any variation in 3C 66A, Mrk 501, or 3C 454.3 during our observations. Nor did we detect any clear evidence of variation in 1ES 2344+514 during our two weeks' observing run of the TeV gamma-ray source.     

Gamma-ray Emission from the γ-ray-loud BL Lac Objects

1 INTaoDUCTIONMany blazar-boe active galedes have recelltly been detected in MeVGeV 7-ray energyrange by detectors on board the Compton Ganuna-Ray Obsewtory (Von Mootigny et al. 1995;Hartman et al. 1999). More recently, TeV ends8ion is obsemd in some object8, such as Mrk421 (z = 0.031, Punch et al. l992), Mrk 501 (z = 0.034, Qbo et al. 1996), 1ES 2344 514(z == 0.044, Catanese et al. 1998), PKS 2155304 (z = 0.117, Chadwick et al. 1999), and1ES 1959 650 (z = 0.048, NisWa 1999). Th…     

On the fairness of the main galaxy sample of SDSS

Flux-limited and volume-limited galaxy samples are constructed from the Sloan Digital Sky Survey(SDSS)data releases DR4,DR6 and DR7 for statistical analysis.The two-point correlation functionsξ(s),monopole of three-point correlation functionsζ0,projected two-point correlation function wp and pairwise velocity dispersionσ12 are measured to test if galaxy samples are fair for these statistics.We find that with the increment of sky coverage of subsequent data releases in SDSS, ξ(s)of the flux-limited sample is...     

A computational method to help identify and measure metallines in high resolution QSO spectra

A computational code is developed to help identify metal absorption linesin high resolution QSO spectra,especially in the Lyα forest.The input to the codeincludes a list of line central wavelengths,column densities and Doppler widths.Thecode then searches for candidate metal absorption systems and assesses the probability that each system could be real.The framework of the strategy we employ isdescribed in detail and we discuss how to estimate the errors in line profile fitting thatare essential to identifi...     

典型强震动加速度仪一致性检验

针对两种典型强震动加速度仪,ETNA与MR2002,利用汶川地震强余震流动观测进行了两仪器的一致性检验.通过架设在同一仪器墩上的2种强震动加速度仪在5次余震事件中所获取加速度记录的波形、峰值、傅里叶振幅谱及反应谱的对比分析可知,ETNA仪器记录的峰值加速度与MR2002仪器记录的峰值加速度间的最大相对误差达23.6％,且南北向峰值加速度差异大于东西向和竖向,竖向明显小于两水平向;反应谱及傅里叶谱变化趋势基本相同,只是幅值存在些微差异,且竖向谱值相差最小,明显小于两水平向,反应谱最大相对误差近5％,相对于低频反应谱,高频反应谱差异较大;此外,亦存在两仪器记录时程曲线反向、记录时间长度不等、触发点不同等差异.经分析认为,这些差异主要是由于两种不同仪器性能上的微差异、仪器参数设置不同、以及触发滤波算法不同等因素引起的.