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31.
Boli basin, between Yishu fracture belt and Dunmi fracture belt, is the biggest Mesozoic coal basin in the east of Heilongjiang Province. Now it is a fault - fold remnant basin. The basin' s shape is generally consistent with the whole distribution of the cover folds, an arc protruding southwards. The basement of the basin can be divided into three fault blocks or structural units. The formation and evoluation of the basin in Mesozoic was determined by the basement fault blocks' displacement features rusulted from by the movement of the edge faults and the main basement faults.  相似文献   
32.
陆烨  赵刚  梁艳春 《天文学进展》2001,19(4):470-476
第一代恒星(星族Ⅲ恒星)标志着宇宙从暗物质时代到现在已知的宇宙的转折点。目前对第一代恒星(星族Ⅲ恒星)的观测结果表明,在银河系中还没有发现零金属丰度的恒星,金属丰度[Fe/H]≤-2.5的恒星极少。由于近几年的BPS巡天,银河系中已知的极端贫金属丰度的恒星数目大大增多。目前,可探测到的极端贫金属星的金属丰度[Fe/H]最低约为-4.1。金属丰度在-4到-3之间的恒星大约有100多颗,这些恒星的运动学特性非常类似于其它晕星。然而还没有发现第一代恒星,或金属丰度[Fe/H]≤-5的恒星。关于第一代恒星的形成过程、初始质量函数以及存在于银河系的什么地方,都还没有任何直接的证据。但第一代恒星确实存在。第一代恒星这个谜一般的实体,向观测和理论天文学家提出了巨大挑战。为探测和预言银河系中的第一代恒星,天文学家提出了许多观测方案和理论模型。对有关第一代恒星在观测和理论研究上的进展进行了综述。  相似文献   
33.
We give a summary of the morphology of the two-ribbon flare of 1981 May 13. One striking feature is that the Ha flare began at about 0338' UT and the double-ribbon structure was formed about 0346, before the impulsive phase of the radio 3 cm burst at 04 11 UT. The 3 cm radio burst flux beginning at 03 33 UT showed only slow, stepwise increases lasting half an hour until the impulsive phase and this type of increase is usually regarded to be a typical thermal process. Each step in the radio flux corresponded to a variation in the Ha flare, showing that the radio and Hα emissions during this period came from the same thermal source. In this paper, we explain this behaviour in terms of Hyder's model: we think that the magnetic trough supporting the solar prominence rose for some reason, causing the prominence matter (the dark filaments) to fall along the magnetic lines and to hit the chromosphere and trigger off the flare. We give rough estimates of the energy density, the height of prominence and the infall matter at the different radio increments. We also give a qualitative explanation for the appearances of the single-peak structure in the radio burst at 0411 and the covering of the sunspot shortly after at 04 13 and propose several possible mechanisms.  相似文献   
34.
FITS、BMP和SCR图象格式及相互转换   总被引:1,自引:0,他引:1  
本文详细介绍图象的FITS格式、BMP格式和SCR格式。FITS格式已经是天文界的通用格式,几乎所有的天文软件包都支持这一格式,而BMP格式在PC计算机上有广泛的运用,有大量PC软件支持BMP图象的显示,处理和打印。云南天文台的SCR格式是PC机采集CCD图象所使用的格式。实现这三种格式的相互转换,就可以自由的将CCD图象在PC机和工作站上进行各种处理。转换的包括图象头和图象数据的转换,其关键在于交换数据的高低字节。  相似文献   
35.
本文在Thorne工作的基础上讨论了吸积盘中黑洞的有关参量的演化,以及由Schwarzschild黑洞吸积盘向Kerr黑洞吸积盘演化过程中对吸积盘辐射通量的影响,最后针对几个典型的辐射过程,分别讨论了黑洞吸积盘在牛顿框架中的温度分布方程与广义相对论的温度分布方程的热不稳定性,并给出此类问题的热不稳定性的判据。  相似文献   
36.
Based on the MASNUM wave-tide-circulation coupled numerical model, the temperature structure along 35°N in the Yellow Sea was simulated and compared with the observations. One of the notable features of the temperature structure along 35°N section is the double cold cores phenomena during spring and summer. The double cold cores refer to the two cold water centers located near 122°E and 125°E from the depth of 30m to bottom. The formation, maintenance and disappearance of the double cold cores are discussed. At least two reasons make the temperature in the center (near 123°E) of the section higher than that near the west and east shores in winter. One reason is that the water there is deeper than the west and east sides so its heat content is higher. The other is invasion of the warm water brought by the Yellow Sea Warm Current (YSWC) during winter. This temperature pattern of the lower layer (from 30m to bottom) is maintained through spring and summer when the upper layer (0 to 30m) is heated and strong thermocline is formed. Large zonal span of the 35°N section (about 600 km) makes the cold cores have more opportunity to survive. The double cold cores phenomena disappears in early autumn when the west cold core vanishes first with the dropping of the thermocline position. Supported by the National Basic Research Program of China (No. G1999043809) and the National Science Foundation of China (No. 49736190).  相似文献   
37.
介绍了近年来河外H2O超脉泽的主要观测结果。H2O超脉泽通常起源于活动星系核中央的拱核盘。它们主要寄生在 Serfert 2星系或低电离核区。至今为止,已有20个星系探测到H2O超脉泽。脉泽辐射的各向同性光度为10~6000L⊙。所有超脉泽星系显示出核的活动,显然,脉泽是由核活动所产生的射电和X射线光子或激波来抽运的。H2O超脉泽倾向存在于高倾斜度的星系,这使得沿视线上的分子柱密度增高,产生足够大的放大光深。最有可能产生H2O超脉泽辐射的星系应有一个包含着射电源的侧向的分子盘以及一个适当的抽运机制。  相似文献   
38.
Technique for Controlling Spread of Limnotic Oncomelania   总被引:1,自引:0,他引:1  
Schistosomiasis is a parasitic disease mostly found in areas along the Changjiang River of China. The disease is spread solely through an intermediary named oncomelania, so its spread of schistosomiasis can be controlled by properly designing water intakes which prevent oncomelania from entering farming land or residential areas. This paper reports a successful design process and a new oncomelania-free intake device. The design of the new intake is based on a sound research program in which extensive experimental studies were carried out to gain knowledge of oncomelania eco-hydraulic behavior and detailed flow field information through CFD simulation.  相似文献   
39.
Radio emission of the historical supernovae remnants Tycho (SNR1572) and Kepler (SNR1604) and evolution of their luminosity are considered. Measurement data of secular luminosity decrease rate, obtained earlier by the authors, were corrected with account of variation in time of the flux density of the reference sources. As a result, it is found that the SNR1604 luminosity at 1667 MHz is weakening with an annual mean rate equal to (0.2 ± 0.07)%. The corresponding rate for SNR1572 is (0.47 ± 0.05)%. Since the radio luminosity evolution, as well as energy densities of magnetic field and relativistic electrons inside SNR1604 and SNR1572 are essentially different, these remnants should be considered as different types of supernovae. Bandiera classified SN1604 as type SNIb or SNII.  相似文献   
40.
The present paper reports 9 species of pontoniine shrimps collected from Hainan IS-land ,South China Sea ,by the Joint Chinese-German Marine Biology Expeditions,in which Peri-climenaeus arabicus (Calman,1939) and Periclimenaeus hecate (Nobili,1904) are recorded for the first time from Hainan Island.  相似文献   
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