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991.
我们于1989年用北京天文台兴隆观测站的60/90/180厘米施密特望远镜及Thomson红敏CCD对14个PG候选激变变星进行光度观测.其光变曲线特性表明:PG0027+260,PG0818+513,和PC1030+590为激变食变星,PG1341—079 是一个可能的激变食变星,PG1551+719为SU UM_a型矮新星,此外还有6个天体的光变曲线有激变星特有的闪变特征.因此PG样本中,激变变星的成功率为79%.PG1030+590的轨道周期为3~h279,PG1717+413的闪变变幅在二个月内有明显变化,它与本身的亮度无明显相关,说明闪变变幅的变化可能是亮斑的局部效应. 相似文献
992.
用天文方法建立商后期甲骨文年代序列的新途径—解析殷历月法 总被引:8,自引:2,他引:6
利用对具有月龄特征的历谱规律的研究成果,以推定甲骨文的绝对年代,从而提供了建立商后期甲骨文年代序列的新方法,并给出了13版卜辞的例证,通过分析殷历月的结构,得出殷历中“二癸月”和“四癸月”的月首分别为首甲日和首癸日,初步归纳出殷历月法,月首为初三,月长等于逆望月周期,建立固定,且找到建立丑之例,置闰规律未知,已存在年终,年中置闰两种闰法。 相似文献
993.
中国古历定朔推步综述 总被引:10,自引:0,他引:10
“朔”简言之表日月黄经相等,先民对其认识经历了一个从平朔到定朔的过程,通过研究古历,文中分析并归纳了不同时期中国古历日制度的基本元素之一-朔的两种推步方法:“积年法”和“《授时历》法”,其中包括平朔,日躔,月离,及定朔的推步方法等;得出了由各历的基本历数直接推出的中国古历定朔计算的一般公式,同时亦给出了《授时历》的推朔法和部分算例。 相似文献
994.
995.
It is apparent that there is a difference between mud coasts and sand coasts in such aspects as sediment components, hydrodynamics
of nearshore waters, and the formative process in configuration, and profile. The intensity distribution of waves affecting
the mud flats in Lianyungang, and the conditions determining tidal water levels, are discussed in this paper. A mathematical
model which describes the erosion process of mud flats has been derived on the basis of the results of tests for the mud process
in seawater. The model is satisfactory for the actual mud flat profile change in Lianyungang with artificial mud discharges. 相似文献
996.
For the period September 1978 to December 1982 we have identified 55 solar flare particle events for which our instruments on board the ISEE-3 (ICE) spacecraft detected electrons above 10 MeV. Combining our data with those from the ULEWAT spectrometer (MPI Garching and University of Maryland) electron spectra in the range from 0.1 to 100 MeV were obtained. The observed spectral shapes can be divided into two classes. The spectra of the one class can be fit by a single power law in rigidity over the entire observed range. The spectra of the other class deviate from a power law, instead exhibiting a steepening at low rigidities and a flattening at high rigidities. Events with power-law spectra are associated with impulsive (<1 hr duration) soft X-ray emission, whereas events with hardening spectra are associated with long-duration (<1 hr) soft X-ray emission. The characteristics of long-duration events are consistent with diffusive shock acceleration taking place high in the corona. Electron spectra of short-duration flares are well reproduced by the distribution functions derived from a model assuming simultaneous second-order Fermi acceleration and Coulomb losses operating in closed flare loops. 相似文献
997.
Active Tectonics of the Mediterranean Region 总被引:32,自引:0,他引:32
Dan McKenzie 《Geophysical Journal International》1972,30(2):109-185
998.
999.
ZHAO Wenzhi WANG Zhaoyun HE Haiqing ZHANG Mingjie WANG Hongjun WANG Yunpeng & QIN Yong . Research Institute of Petroleum Exploration & Development PetroChina Beijing China . PetroChina Exploration & Production Beijing China . Department of Geology Lanzhou University Lanzhou China . Guangzhou Geochemical Institute Chinese Academy of Sciences Guangzhou China . China University of Mining Technology Xuzhou China 《中国科学D辑(英文版)》2005,48(4):441-453
It has been proven in exploration practice that thecarbonates in China not only can generate hydrocar-bons, but also form commercial reservoirs. The car-bonates are different from clastic rocks in view of theirdeposition environment as well as their sedimentaryand diagenetic processes. Therefore, the evaluationcriteria and hydrocarbon generation mechanism forcarbonates can not be the same as that for clasticrocks, and it is important to establish a special hydro-carbon generation mechanism and… 相似文献
1000.
The primary goal of this paper is to stimulate discussion and promote the use of mollusc models and multidisciplinary research approaches in the field of environmental toxicology. Molluscs are effective models because they are ubiquitous, have highly conserved control and regulatory pathways that are often homologous to vertebrate systems, and are extremely sensitive to anthropogenic inputs. We have attempted to provide initial references as an avenue into the literature and as a means for researchers to expand their thoughts to regions outside of their own area of expertise. The authors are particularly interested in developing multidisciplinary international collaborative efforts. 相似文献