共查询到18条相似文献，搜索用时 265 毫秒
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布朗族使用傣历（祖葛历）,以月份结合物候变化指导生产,生活中使用７ｄ（天）为１轮的纪日制度,并将７个日名赋予不同寓意。这种状况可能距今只有２００余年的历史,在此以前的历法,由于没有文字记录而被完全淡忘了,但从其先民的崖画和口头流传的传说中,有阴阳并重、同时崇拜太阳和月亮的内容看,是处于阴阳合历初期的“物候历”,其内容应与佤族（清朝时分化）的阴阳历相似。 相似文献
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云南丰富多彩的少数民族传统文化，在天文方面呈现为“物候历”、太阳历和阴阳合历等等，曾在历史上长期并存使用，与各个民族的社会经济发展相适应。这种现象与民族的迁徙紧密联系，早期的越人和羌人迁徙云南，可追溯到战国时期，甚至是新石器时期。大规模的迁徙意味着文化的迁徙，迁徙可促进文化的发展，也可使文化倒退，重要的原因之一，是能否与外界进行交流，吸取先进的成分来发展自己。认同他人的某些传统内容，也会形成地域性的共同文化现象，除历法外，鼓文化也是典型例子。 相似文献
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一星漫三国 东汉末年,三国鼎立,而天历测星畴人,则飘落各方,为所栖身之国提供推行天文律历之术。蜀国使用后汉四分历：魏国早期也使用此历,后改用景初历：吴国使用乾象历（上次聊六介绍的刘洪那部优秀的历法《乾象历》,在东汉末期的时代并没有被采用,竟被冷遇了四十多年后才在三国时期的东吴得以颁行）。 相似文献
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Apophis是一颗对地球具有高潜在威胁的小行星（Potentially Hazardous Asteroid,PHA）．对其开展高精度定位观测可为精确计算其轨道提供基本数据。2013年2月4～7日,使用云南天文台2．4m望远镜云南暗弱天体光谱及成像仪（YunnanFaint-Obiect Spectrograph and Cainera．YFOSC）对Apophis进行观测,采用天体测量软件Astrometrica处理原始CCD图像,获得了一批定位结果,并与JPL历表和IMCCE历表进行了外部比较,结果表明,当与JPL历表比较时,赤经、赤纬两个方向的观测位置减去计算位置（0一C）不大于O．1arcsec,每个方向单次测量精度约为0．1arcsec。 相似文献
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哈尼族原始的历法,是将一年分成10个月、每个月固定为36天,另外5～6天余日用于过新年,简称十月历。在受到汉族的农历影响、接受了一年分成12个月的概念后,十月历与十二月历被混淆在一起,出现了有月份重叠的现象,即在生活中,注重以十二生肖纪日,以物候指导生产,纪月相当模糊,相差几天也无所谓的局面。 据哈尼族的神话传说和云南绿春县的白氏家谱分析,哈尼族从使用十月历转向接受十二月历的概念,约开始于公元14世纪,而后逐渐扩展开来,十月历渐渐被淡忘。但是,转向完全使用农历,却经历了漫长的历史时期,直至1950年还没有完成这一转变过程,主要原因是经济发展极端缓慢,交通困难,很少与外部进行交流。 相似文献
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傣族历法是自成体系的阴阳合历, 其中的干支纪日纪年法是重要的组成部分, 并与汉族历法有渊源关系, 既保留有古汉语的读音, 又继承着称为“母子”的习惯。对其由来, 以往的一些讨论并未得到圆满的解释, 本文从迁徙史的角度提出, 傣族历法中的干支等内容, 是其先民从中原迁徙而带入今云南傣族地区。 相似文献
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傣族历法是自成体系的阴阳合历,其中的干支纪日纪年法是重要的组成部分,并与汉族历法有渊源关系,既保留有古汉语的读音,又继承着称为“母子”的习惯,对其由来,以往的一些讨论并未得到圆满的解释,本文从迁徙的角度提出,傣族历法中的干支等内容,是其先民从中原迁徙而带入今云南傣族地区。 相似文献
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云南丰富多彩的少数民族传统文化，在天文方面呈现为“物侯历”、太阳历和阴阳合历等等，曾在历史上长期并存使用，与各个民族的社会经济发展相适应。这种现象与民族的迁徒紧密联系，早期的越人和羌人迁徒云南，可追溯到战国时期，甚至是新石器时期。大规模的迁徒意味着文化的迁徒，迁徒可促进文化的发展，也可使文化倒退，重要的原因之一，是能否与外界进行交流，吸取先进的成分来发展自己。认同他人的某些传统内容，也会形成地域性的共同文化现象，除历法外，鼓文化也是典型例子。 相似文献
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本对一批中心星光度大于１０＾３Ｌ⊙质量大于７～８Ｍ⊙的大质量年轻星体（ＹＳＯｓ）进行了研究,利用近几年对这批源进行的ＪＨＫ波段的观测以及其它台站的红外测光和ＩＲＡＳ点源资料,得到了这批源的红外能谱,根据它们在７－２３μｍ间的低分辨率光谱（ＬＲＳ）确定了其尘埃粒子的类型,并将其分三类;（１）具有９．７μｍ的硅酸盐特征;（２）具有１１．３μｍ的ＰＡＨ特征;（３）特征不明显或谱噪音较大,本采用球对称 相似文献
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元代郭守敬等1280年编制的《授时历》是中国本土科学家研制的最后一部历法,具有极高的精度。采用其仍可预报2012年5月21日发生的日食,其预报北京地区的见食情况时食甚时刻误差4 min,食分误差为0.04。给出了《授时历》推步的1990～2050年北京的见食情况及精度,其中食甚时刻的标准偏差为103.04 min,食分的标准偏差则不低于0.33。通过考察1280～2050年间186个日食计算结果,可得出《授时历》自行用以来推步日食的误差,考虑到存在错报(不可见)和漏报因素的影响,其食甚时刻和食分的标准偏差分别不低于50.65 min和0.19;同时指出,随着行用时间的延长其推时误差也逐步放大。 相似文献
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Peat cores from ombrotrophic bogs have been used as a valuable archive to study environmental change for over a century. Much of this focus on the peat record has been on biological proxies of environmental change, such as pollen and peat-forming macrofossils, but there is growing interest in the geochemical record to study environmental changes. Several studies of long-term peat records in Europe have reconstructed past changes in atmospheric lead pollution, for example, and the general cohesiveness of the results and their agreement with known historical trends in metal production exemplify the best potential of peat geochemistry as an environmental archive. Based on the success with lead, a current emphasis in peat reconstructions is to assess the record of past mercury deposition and results thus far show generally consistent trends, e.g., a pre-anthropogenic mercury accumulation rate of about 0.5–1.5 μg Hg m− 2 year− 1. Despite this general consistency there is increasing concern that there may be diagenetic effects on the quantitative record of some metals, which can be inferred based on a strong relationship between mercury and other organically bound elements and proxies for peat decomposition (C/N ratio). However, it is possible that changes in decomposition and the alteration of some metal records could provide climatic information. A few recent studies show that closer examination of the geochemical matrix, in some cases along with biological proxies, can provide valuable information on landscape changes and climate; for example, partitioning metals into different weight fractions and source regions can be applied to climate studies. The best interpretations of the peat geochemical record in the context of environmental and climate change will likely come when geochemical and biological records are considered simultaneously. 相似文献
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“干支回推法”是针对中国历史时期所特有的干支材料而设计的新天文年代学方法．以一组假设的材料为例,系统地给出了该方法的完整求解过程．指出该方法的优势在于准确高效,能有效地处理某些年代学难题．此外,除材料的公历日期外还能将当时的历法细节一同迭代解出． 相似文献
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M.S. Dimitrijevi&#x; 《Astronomische Nachrichten》2002,323(6):570-573
The contribution to European astronomy of Milutin Milanković is analyzed. A crater on the far side of the Moon, a crater on Mars, and asteroid 1605 are named after this most distinguished Serbian astronomer. He explained the phenomenon of the ice ages by an astronomical theory. Milanković elucidated also the history of the Earth's climate as well as that of planet Mars, and in addition he was the author of the mathematical theory of climate and of the Earth's polar motion. He did important contributions to celestial mechanics and the history of astronomy, and was a great popularizator of science. At the orthodox church council in 1923 in Istanbul, he submitted a proposal concerning the reform of the calendar, elaborated by him and by Maksim Trpković, providing for a more exact calendar than the Gregorian one. The calendar of Milanković is now used by some orthodox churches, such as the Greek and Romanian ones. 相似文献
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Abstract— It has been known for some time that the volume of impact melt (Vm) relative to that of the transient cavity (Vtc) increases with the magnitude of the impact event. This paper investigates the influence that this phenomenon has on the nature of terrestrial impact craters. A model of impact melting is used to estimate the volume of melt produced during the impact of chondritic projectiles into granite targets at velocities of 15, 25, and 50 km S?1. The dimensions of transient cavities formed under the same impact conditions are calculated from current crater-scaling relationships, which are derived from dimensional analysis of data from cratering experiments. Observed melt volumes at terrestrial craters are collated from the literature and are paired with the transient-cavity diameters (Dtc) of their respective craters; these diameters were determined through an established empirical relationship. The model and observed melt volumes have very similar trends with increasing transient-cavity diameter. This Vm-Dtc relationship is then used to make predictions regarding the nature of the terrestrial cratering record. In particular, with increasing size of the impact event, the depth of melting approaches the depth of the transient cavity. As a consequence, the base of the cavity, which ultimately would appear as an uplifted central structure in a complex crater, will record shock stresses that will increase up to a maximum of partial melting. Examination of the terrestrial record indicates a general trend for higher recorded shock levels in central structures at larger diameters; impact structures in the 100-km size range record partially melted and vesiculated parautochthonous target rocks in their centers. In addition, as the depth of melting approaches a depth equivalent to that attained by the base of the transient cavity, the floor of the transient cavity will have progressively less strength, with the result that cavity modification and uplift will not produce topographic central peaks. Again, the observed terrestrial record is not inconsistent with this prediction, and we offer differential melt scaling as a possible mechanism for the transition from central topographic peaks to rings with increasing crater diameter. Among other implications is the likelihood that impact basins in the 1000-km size range on the early Earth would not have the same multi-ring form as observed on the moon. 相似文献
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Data from our compiled catalog of spectroscopically determined magnesium abundances in stars with accurate parallaxes are used to select thin-disk dwarfs and subgiants according to kinematic criteria. We analyze the relations between the relative magnesium abundances in stars, [Mg/Fe], and their metallicities, Galactic orbital elements, and ages. The [Mg/Fe] ratios in the thin disk at any metallicity in the range ?1.0 dex <[Fe/H] < ?0.4 dex are shown to be smaller than those in the thick disk, implying that the thin-disk stars are, on average, younger than the thick-disk stars. The relative magnesium abundances in such metal-poor thin-disk stars have been found to systematically decrease with increasing stellar orbital radii in such a way that magnesium overabundances ([Mg/Fe] > 0.2 dex) are essentially observed only in the stars whose orbits lie almost entirely within the solar circle. At the same time, the range of metallicities in magnesium-poor stars is displaced from ?0.5 dex < [Fe/H] < +0.3 dex to ?0.7 dex < [Fe/H] < +0.2 dex as their orbital radii increase. This behavior suggests that, first, the star formation rate decreases with increasing Galactocentric distance and, second, there was no star formation for some time outside the solar circle, while this process was continuous within the solar circle. The decrease in the star formation rate with increasing Galactocentric distance is responsible for the existence of a negative radial metallicity gradient (grad R[Fe/H] = ?0.05 ± 0.01 kpc?1) in the disk, which shows a tendency to increase with decreasing age. At the same time, the relative magnesium abundance exhibits no radial gradient. We have confirmed the existence of a steep negative vertical metallicity gradient (grad Z[Fe/H] = ?0.29 ± 0.06 kpc?1) and detected a significant positive vertical gradient in relative magnesium abundance (grad Z[Mg/Fe] = 0.13 ± 0.02 kpc?1); both gradients increase appreciably in absolute value with decreasing age. We have found that there is not only an age-metallicity relation, but also an age-magnesium abundance relation, in the thin disk. We surmise that the thin disk has a multicomponent structure, but the existence of a negative trend in the star formation rate along the Galactocentric radius does not allow the stars of its various components to be identified in the immediate solar neighborhood. 相似文献