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431.
Butler Shearer Redfern Colhoun O'Kane Penny Morris Griffiths & Cullum 《Monthly notices of the Royal Astronomical Society》1998,296(2):379-391
The Galway/DIAS Image Sharpening Camera, TRIFFID, has been used to make observations in two colours of the centre of the post-core-collapse globular cluster M15. We present here our analysis of the photometry in B over two seasons. We have combined the complementary qualities of the HST 's high astrometric precision and TRIFFID's extended coverage and photometric precision, to perform crowded-field photometry in the innermost region of M15. Our technique virtually eliminates the problem of extreme crowding which has hitherto hampered studies of the variable star populations in globular cluster cores, and thereby provides an extension of the HST 's capability. Candidate variables detected with the HST have been confirmed and monitored over longer periods. We show that most of these are RR Lyrae stars, and that one is a short-period Type II Cepheid (the third to be discovered in M15). Our photometric study also produced evidence of a similar number of new variables. These also appear to be RR Lyrae stars, except for a possible eclipsing system. Further data from an upgraded version of TRIFFID have recently been obtained to help to refine the light curves of all these objects. 相似文献
432.
Tim Naylor 《Monthly notices of the Royal Astronomical Society》1998,296(2):339-346
This paper is primarily an investigation of whether the 'optimal extraction' techniques used in CCD spectroscopy can be applied to imaging photometry. It is found that using such techniques provides a gain of around 10 per cent in signal-to-noise ratio over normal aperture photometry. Formally, it is shown to be equivalent to profile fitting, but offers advantages of robust error estimation, freedom from bias introduced by mis-estimating the point spread function, and convenience. In addition some other techniques are presented, which can be applied to profile fitting, aperture photometry and the 'optimal' photometry. Code implementing these algorithms is available at http://www.astro.keele.ac.uk/~timn/. 相似文献
433.
浦城地区火山岩型铀成矿远景预测 总被引:1,自引:0,他引:1
本文根据浦城地区的成矿地质条件,利用信息量法、逻辑矢量长度法和逻辑矢量长度加权法,在已有成矿地质模型的基础上,筛选出有利的地质变量。根据地质变量对成矿的贡献大小,建立评价模型,圈出有利成矿区。经地质评价,认为各有利成矿区成矿条件有利,有较大的找矿前景。 相似文献
434.
傅立叶变换红外光谱联用技术在化石燃料分析中的应用 总被引:2,自引:0,他引:2
对傅立叶变换红外光谱联用技术在化石燃料分析中的应用进行了较全面的总结评述,重点介绍了气相色谱/红外光谱联机、高压液相色谱/红外光谱联机、薄层色谱/红外光谱联机、超临界流体色谱/红外光谱联机、裂解色谱/红外光谱联机、热重分析/红外光谱联机、气相色谱/红外光谱/质谱三机联用技术等在化石燃料的结构组分分析、成因机理研究及其勘探等诸方面的重要应用,尤其是在芳香族化合物和几何异构体的分离鉴定方面发挥出的突出功效。引用文献59篇。 相似文献
435.
Numerical Simulation of the 1918 Puerto Rico Tsunami 总被引:1,自引:0,他引:1
The Caribbean Sea region is well known for its hurricanes, and less known for tsunamis. As part of its responsibilities in hazard assessment and mitigation, the U.S.A. Federal Emergency Management Agency, and the Puerto Rico Civil Defense, funded a pilot study to perform a numerical simulation of the 1918 Puerto Rico tsunami, one of the most deadly in the region. As part of the study a review has been made of the tectonic and tsunamigenic environment around Puerto Rico, the fault parameters for the 1918 event have been estimated, and a numerical simulation has been done using a tsunami propagation and runup model obtained through the Tsunami Inundation Modeling for Exchange (TIME) program. Model results have been compared with the observed runup values all along the west coast of Puerto Rico. 相似文献
436.
Development of Seismic Risk Scenarios Based on a Hybrid Method of Vulnerability Assessment 总被引:11,自引:5,他引:6
A hybrid methodology of vulnerability analysis is presented, involving elements from both empirical and theoretical methods. A model for correlating analytically calculated structural damage indices to loss (in monetary terms) is also proposed and calibrated against available statistical data. Probability damage matrices derived using this methodology are incorporated into a cost-benefit model tailored to the problem of estimating the feasibility of seismically rehabilitating the existing stock of reinforced concrete buildings in Thessaloniki, Greece. Losses calculated using the suggested procedure are found to be in good agreement with losses incurred during the 1978 Thessaloniki earthquake. The results of the present study also indicate that benefit/cost ratios for reinforced concrete buildings are quite low. Hence, it appears that a pre-earthquake strengthening programme is not economically justifiable. 相似文献
437.
脆弱生态环境定量评价方法的研究 总被引:132,自引:4,他引:128
建立了一套系统、完整、客观、灵活且具较强可操作性的脆弱生态环境定量评价指标体系及方法,并通过用此法评价全国26个省、区生态环境脆弱度的方式,对其可操作性和准确性进行了验证。 相似文献
438.
新疆破坏性地震损失“盲估”方法 总被引:1,自引:1,他引:0
通过总结新疆近年来的震害预测研究成果和震害损失评估工作的实践,给出了震后损失快速评估方法-“盲估”方法。提出今后震灾评估的发展方向是建立震后趋势快速判定计算机管理系统。 相似文献
439.
震后灾害损失盲场快速评估的技术方法及其计算机软件系统可在确定地震震级、震中位置和发震时间等参数后,在人员未到地震现场的情况下,快速给出该次地震对一个区域造砀 经济损失和人员伤亡的初步评估结果。选择鲁南地震重点监视防御区为评估区域,并使用该软件系统对1995年9月-20日发生在苍山的5.2级地震进行了灾害损失快速评估的实际检验。从检验结果可看出 ,用固定资产损失率矩阵计算经济损失,获得基础资料方便, 相似文献
440.