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21.
Samples of ancient Indian lime plaster have not previously been analysed. Excavation of a seventh century AD baked brick structure provided the necessary samples for a detailed laboratory examination of plaster. The plaster samples were studied by chemical and petrographic methods. The probable sources of lime and sand were indicated by the mineralogy. 相似文献
22.
利用热释光测定年代技术对青龙镇出土样品的烧造年代进行检测分析,以求帮助了解不同历史时期青龙镇瓷器贸易的发展状况。为此,本工作以青龙镇遗址出土瓷器中的67件瓷片及4件砖瓦样品为研究对象,用热释光前剂量饱和指数法测定瓷片样品古剂量;用热释光高温细颗粒技术测定砖瓦样品古剂量;用厚源α粒子计数法和X射线荧光光谱技术测量样品年剂量。瓷片样品热释光年代结果从唐代至南宋不等,砖瓦样品年代结果为北宋时期烧造,与文献记载中隆平寺塔的始建时间相符。 相似文献
23.
陶大卫 《文物保护与考古科学》2018,30(2):1-9
人牙结石淀粉粒分析是开展古代居民食物来源研究的有效途径之一。用此方法对河南新郑裴李岗遗址仅存的两具裴李岗文化人骨牙齿上的结石开展了淀粉粒分析,成功提取出38颗淀粉粒,其中可鉴定种属的淀粉粒主要来自于栎属、豆科和块茎类等非农作物,少量有可能来自于粟黍类作物。虽然分析样品较少,提取出的淀粉粒数量不多,但这一结果或许表明采集植物有可能构成了裴李岗遗址居民植物性食物的主体。结合贾湖、莪沟、石固和寨根等裴李岗文化遗址的植物考古学研究,裴李岗文化居民的食物结构具有广谱性特征。本研究为全面认识中原地区裴李岗文化居民食物构成和聚落生业经济,深入探讨中原地区早期农业形成过程等提供了新思路和新证据。 相似文献
24.
当前已经开始的西部大开发 ,是事关我国现代化建设和中华民族长远生存与发展的重大战略问题。本文在详细分析了西部现有生态环境的基础上 ,对在大开发中如何保护自然环境及进行生态建设作了论证。 相似文献
25.
It is well known from nature and experiments that the presence of brine strongly affects the microstructural evolution and the mechanical and transport properties of halite. Existing interpretations of the grain boundary structure in deformed, wet, salt samples annealed statically at room temperature are based on indirect evidence from reflected light microscopy and conventional scanning electron microscopy. This paper presents direct observations of fluid‐filled grain boundaries using the cryogenic‐scanning electron microscope (cryo‐SEM) in which the grain boundary fluids were frozen before breaking the samples. The rapid cooling transforms the brine into two phases, i.e. ice and hydrohalite, which are easily recognized from characteristic segregation patterns. We studied samples of wet, synthetic, polycrystalline halite annealed under static conditions at room temperature. In coarse‐grained samples, fine‐scale segregation patterns were observed at the boundaries of the primary recrystallizing grains. These points indicate the existence of fluid films with a thickness in the range of 30 nm, but the finer scale structure of the fluid remains unknown. In fine‐grained samples, the distribution and reorganization of fluids with annealing time is recorded by the combination of contact healing and successive accumulation of fluids in triple junction tubes. The contact healing is attributed to the small initial grain size, such that the fluid film necks down by accumulating the fluids into previously existing triple junctions via neck growth. Electron backscatter diffraction measurements of both primary and secondary recrystallized grains indicate that they are euhedral, i.e. the grain growth morphology is controlled by the anisotropy of the grain boundary energy of the growing grain, which results in planar growth faces. 相似文献
26.
在英国王室珍藏(The Royal Collection)收藏的中国瓷器有着近五百年的历史,这其中既包括外销瓷,也包括赏赉瓷器,而最难得瓷器珍品则是乾隆皇帝与慈禧太后赠送给英国君王的外交礼品用瓷。通过对英国王室珍藏初步的观察与判断,可以看出其反映了清代中英外交与贸易关系的变化,侧面反映了十八之十九世纪清朝由盛转衰的历史。 相似文献
27.
统购统销初期的粮食票证制度探析--以1953~1957年的河南为个案 总被引:1,自引:0,他引:1
1953~1957年的河南在统购统销初期实施粮食票证制度,经历了初创时期、基本成型时期、确立时期三个不同的发展阶段。粮食票证制度的形成,对于保证粮食统购统销政策的贯彻实施提供了有力的保障,并成为粮食统购统销制度的一个重要组成部分。 相似文献
28.
A major Alpine‐type peridotite located at Almklovdalen in the Western Gneiss Region of Norway was infiltrated by aqueous fluids at several stages during late Caledonian uplift and retrogressive metamorphism. Following peak metamorphic conditions in the garnet–peridotite stability field, the peridotite experienced pervasive fluid infiltration and retrogression in the chlorite–peridotite stability field. Subsequently, the peridotite was infiltrated locally by nonreactive fluids along fracture networks forming pipe‐like structures, typically on the order of 10 m wide. Fluid migration away from the fractures into the initially impermeable peridotite matrix was facilitated by pervasive dilation of grain boundaries and the formation of intragranular hydrofractures. Microstructural observations of serpentine occupying the originally fluid‐filled inclusion space indicate that the pervasively infiltrating fluid was characterized by a high dihedral angle (θ > 60°) and ‘curled up’ into discontinuous channels and fluid inclusion arrays following the infiltration event. Re‐equilibration of the fluid phase topology took place by growth and dissolution processes driven by the excess surface energy represented by the ‘forcefully’ introduced external fluid. Pervasive fluid introduction into the peridotite reduced local effective stresses, increased the effective grain boundary diffusion rates and caused extensive recrystallization and some grain coarsening of the infiltrated volumes. Grain boundary migration associated with this recrystallization swept off abundant intragranular fluid inclusions in the original chlorite peridotite, leading to a significant colour change of the rock. This colour change defines a relatively sharp front typically located 1–20 cm away from the fractures where the nonreactive fluids originally entered the peridotite. Our observations demonstrate how crustal rocks may be pervasively infiltrated by fluids with high dihedral angles (θ > 60°) and emphasize the coupling between hydrofracturing and textural equilibration of the grain boundary networks and the fluid phase topology. 相似文献
29.
Both macrofossil and microfossil plant remains from the grass family (Poaceae) have been recovered from Neolithic and historic sites in China. Basing our work on the plant taxa that were previously recovered, we analyzed the economically significant genera for modern starch grain analysis with a focus on the important tribe Triticeae. Modern starch grains from the tribe Triticeae were compared with those from other grasses, and criteria for identification were determined. In total, 38 species within 28 genera, 13 tribes and 4 subfamilies were selected for analysis. Results demonstrate that starch grains from members of the tribe Triticeae are discernible from those of other tribes by their distinctive lenticular morphologies and surficial pressure craters. A dichotomous key covering 10 species within 7 genera of the Triticeae was created, thus allowing identification of members of the tribe to the level of genus. Application of the dichotomous key to the ancient starch assemblage recovered from lithic tools excavated from the early Neolithic site of Donghulin demonstrates that plants from the genera Hordeum and Agropyron were exploited alongside millets at this site. 相似文献
30.
"贡瓷"及与其相关的"官窑"制度是中国古代瓷业生产中的重要学术问题。文物考古界一般认为,中国的"贡瓷"制度开始于唐代,烧制优质"贡瓷"的"官窑"制度则始于晚唐或宋代。然而,近年来在湖南湘阴窑和南京发现的"太官"、"供奉"、"上府"铭瓷器标本证实,"贡瓷"制度最迟开始于南北朝时期。湘阴窑址出土的刻有多种瓷业工人姓氏及"官"款的窑具资料可能还把中国烧制"贡瓷"的"官窑"制度开始的时间提前到南朝或隋代。 相似文献