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A wide-field time-series CCD photometric survey of variable stars in the field of the open cluster NGC 2168 was carried out using the BATC Schmidt telescope. In total 13 new variable stars are discovered with three W UMa systems, one EA type and two EB type eclipsing binaries (one of them could be a W UMa system), and seven pulsating stars including three candidates of δScuti stars. 相似文献
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Xi-Liang Zhang Xiao-Bin Wang Li-Yun Zhang National Astronomical Observatories / Yunnan Observatory Chinese Academy of Sciences Kunming Graduate School of Chinese Academy of Sciences Beijing 《中国天文和天体物理学报》2006,6(6):729-732
We measured the light-curve of the asteroid (147) Protogeneia in November 2004, with a CCD detector attached to the 1-meter telescope at the Yunnan Observatory, China. The synodic period and maximum amplitude of (147) at this apparition are 7.852 hours and 0.25 mag, respectively. The value of a/b for (147), from a preliminary estimation, is not less than 1.26:1. 相似文献
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Three selected asteroids, numbered 58, 360 and405, were observed during 2000at Yunnan Observatory, China. Thenew lightcurves are presented inthis paper. The synodic period of (58)Concordia is estimated as 9.90 ± 0.01hfor the first time. The synodic period of (405) Thia derived from ourobservation is 9.96 ± 0.01h, which is slightly different from the previousresult. For 360, we obtained the synodic period of 6.18 ± 0.02h which isconsistent with previous values. Additionally, the BV and UB-colourindexes for the three asteriods were also determined. 相似文献
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Yu Xin Xiao-Bin Zhang Li-Cai DengNational Astronomical Observatories Chinese Academy of Sciences Beijing 《中国天文和天体物理学报》2002,2(6)
We present a snapshot of our recent results of a variable star survey in 1 degree fields around three open clusters: NGC 188, NGC 7789 and M67. A total number of 39 variable stars are newly discovered, including 22 W UMa stars, 10 EA (Algol) type binaries, one RR-lyr and one RRd pulsator, and five unclassified variables. 相似文献
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海洋热流数据是开展海洋地球动力学研究和油气资源评价的基础数据.为深入认识琼东南盆地的地热特征,本文首先利用耦合沉积作用与岩石圈张裂过程的数值模型分析了张裂型盆地主要地热参数的垂向变化特征;并通过钻孔资料的详细分析,获得了琼东南盆地44口钻孔的热流数据;结合海底地热探针获取的热流数据,对琼东南盆地地热特征及其主要影响因素进行了简要分析.结果表明:沉积作用的热披覆效应对表层热流有较明显的抑制作用,由于沉积物生热效应与披覆效应的共同作用,同一钻孔处海底表层热流与钻孔深度3000~4000m处热流或与海底间的平均热流差异很小,可以一起用于分析琼东南盆地的热流分布特征;莺歌海组、乐东组热导率随深度变化小于黄流组及其下地层热导率的变化,钻孔沉积层平均热导率约为1.7 W·(m·K)-1,钻孔地层生热率一般低于2.5μW·m-3,平均生热率为1.34μW·m-3,平均地温梯度主要介于30~45℃/km,热流介于50~99mW·m-2,陆架区热流主要集中于60~70mW·m-2,深水区钻孔具有较高的地温梯度和热流值;从北部陆架与上陆坡区往中央坳陷带,热流值从50~70mW·m-2,增高为65~85mW·m-2,并且往东有升高趋势,在盆地东部宝岛凹陷、长昌凹陷与西沙海槽北部斜坡带构成一条热流值高于85mW·m-2的高热流带.进一步分析认为,琼东南盆地现今热流分布特征是深部热异常、强烈减薄岩石圈的裂后冷却作用、晚期岩浆热事件、地壳与沉积层的生热贡献以及沉积作用的热披覆效应等多种主要因素综合作用的结果. 相似文献
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基于第三代海浪数值模式WAVEWATCHⅢ(v3.14),在WRF模式提供模式风场驱动下,对1109号台风"梅花"的风浪场、涌浪场和混合浪场进行了数值模拟,并在我国东部沿海选取了3个关注站点,探讨涌浪和风浪波高随时间变化与台风中心位置的关系以及台风影响下海浪二维谱、风浪场和涌浪场分布和变化特征。结果表明,新版的海浪模式能较好表现福建和浙江沿海、长江口附近、山东半岛南端的3个关注区域的台风涌浪先于风浪到达的事实;距台风中心不同距离,混合浪波高的组成和波高变化不同;台风的外围区涌浪场的高值区对应着风浪场的低值区,台风的大风区风浪场的高值区对应着涌浪场的低值区,台风眼区则为涌浪区。涌浪多分布在台风风浪影响范围之外,波向由台风中心向外辐射。 相似文献
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2009年利用大功率人工源极低频电磁技术(CSELF)在位于华北、华南、东北、西北和西南的12个地震台站和几个流动观测点进行了连续30天新的观测试验.结果表明,利用CSELF技术可以在1700 km之外测量到人工源电磁场信号,计算得到的电、磁场功率谱密度和视电阻率与天然源信号相比,抗干扰能力更强,观测信号更稳定,特别有利于识别和捕捉地震等诱发的电磁异常现象,在地震预测监测中具有很大的研究应用潜力.试验还发现,各地震台站和流动测点观测的CSELF信号的强度,与台站或者测量的电、磁场分量相对于发射源的距离、方位有明显的关系;发现在离开发射源的相对近区,场强随距离的衰减,比在相对远区更快;发现接收磁场信号比电场信号较易获得更高信噪比的数据. 相似文献
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大功率人工源极低频电磁波（Control Source of Extremely Low Frequency method, CSELF）技术中,辐射天线由布设在高大地电阻率区的接地长导线源构成,通过接地点向大地注入数百安培的强电流.目前有关强电流在大地中的流动特性和分布规律,尚未完全弄清楚.本文提出一个新思路,将CSELF发射天线分解为两部分:交变的接地长导线源和接地处的交流点电流源,二者响应的叠加构成总场.本文重点讨论了均匀空间下交流点电流源的求解,对比研究了交流点电流源响应、直流点电流源响应之间的差异.结果表明,在小范围内（场源距几十、几百米以内）,均匀空间下交流点电流源场和直流源场差别较小,可相互近似,但在大范围内,交流点电流场比直流场的衰减要快得多.由于CSELF辐射天线跨度上百公里,场源距很大,其电流分布规律遵循交变场规则,不能近似为直流场. 相似文献
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Li-Feng Xing Shuang-Yi Zhao Wei Su Yan Shen Xiao-Bin Zhang Jian-Yan Wei 《中国天文和天体物理学报》2007,7(4):551-557
We monitored 16 X-ray selected young solar-type stars for light variation and found appreciable periodic light variability with amplitudes of a few hundredths of a magni-tude in nine of the objects. Using the method of Phase Dispersion Minimization (PDM) and Fourier analysis (software PERIOD04), the rotation periods of these stars were determined from the photometric data. The rotation periods of all nine stars are shorter than about 3days. It is suggested that, as with the Pleiades cluster, small amplitude light variations are quite common among young solar-type stars with rotation periods around 3 days or less. This gives further evidence for the spin up of solar-type stars predicted by models of angular momentum evolution of pre-main sequence stars. 相似文献