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61.
62.
宜阳故城、阳翟故城和新郑韩城是战国时期韩国在进军中原的过程中先后建立的三个都城,这三大都城在选址、宫城和宫殿区以及防御设施和体系的营建、陵区的规划等方面有着明显的相似性。同时,受不同历史条件的影响,也表现出了很大的差异性,比如都城性质、城郭布局、破郑风水等。这些异同的比较有助于我们探讨当时韩国的社会和历史面貌。 相似文献
63.
Capillary trapping is a physical mechanism by which carbon dioxide (CO2) is naturally immobilized in the pore spaces of aquifer rocks during geologic carbon sequestration operations, and thus a key aspect of estimating geologic storage potential. Here, we studied capillary trapping of supercritical carbon dioxide (scCO2), and the effect of initial scCO2 saturation and flow rate on the storage/trapping potential of Berea sandstone. We performed two‐phase, scCO2‐brine displacements in two samples, each subject to four sequential drainage–imbibition core‐flooding cycles to quantify end‐point saturations of scCO2 with the aid of micro‐ and macro‐computed tomography imaging. From these experiments, we found that between 51% and 75% of the initial CO2 injected can be left behind after the brine injection. We also observed that the initial scCO2 saturation influenced the residual scCO2 saturation to a greater extent than the rate of brine injection under the experimental conditions examined. In spite of differences in the experimental conditions tested, as well as those reported in the literature, initial and residual saturations were found to follow a consistent relationship. 相似文献
64.
Metal‐catalysed CO2 hydrogenation is considered a source of methane in serpentinized (hydrated) igneous rocks and a fundamental abiotic process germane to the origin of life. Iron, nickel, chromium and cobalt are the catalysts typically employed in hydrothermal simulation experiments to obtain methane at temperatures >200°C. However, land‐based present‐day serpentinization and abiotic gas apparently develop below 100°C, down to approximately 40–50°C. Here, we document considerable methane production in thirteen CO2 hydrogenation experiments performed in a closed dry system, from 20 to 90°C and atmospheric pressure, over 0.9–122 days, using concentrations of non‐pretreated ruthenium equivalent to those occurring in chromitites in ophiolites or igneous complexes (from 0.4 to 76 mg of Ru, equivalent to the amount occurring approximately in 0.4–760 kg of chromitite). Methane production increased with time and temperature, reaching approximately 87 mg CH4 per gram of Ru after 30 days (2.9 mgCH4/gru/day) at 90°C. At room temperature, CH4 production rate was approximately three orders of magnitude lower (0.003 mgCH4/gru/day). We report the first stable carbon and hydrogen isotope ratios of abiotic CH4 generated below 100°C. Using initial δ13CCO2 of ‐40‰, we obtained room temperature δ13CCH4 values as 13C depleted as ?142‰. With time and temperature, the C‐isotope separation between CO2 and CH4 decreased significantly and the final δ13CCH4 values approached that of initial δ13CCO2. The presence of minor amounts of C2‐C6 hydrocarbons is consistent with observations in natural settings. Comparative experiments at the same temperatures with iron and nichel catalysts did not generate CH4. Ru‐enriched chromitites could potentially generate methane at low temperatures on Earth and on other planets. 相似文献
65.
位于长江入海口的“长江口二号”清代沉船是中国目前发现的保存最为完整的古代木制沉船之一,已于2022年11月完成整体打捞。在进行水下考古调查时,沉船出水的部分青花瓷出现的病害现象引起了考古工作者的关注,特别是裂纹中黑色污染物及表面铁锈状污染物对文物的外观产生了很大影响。本工作选取了三件具有典型被污染特征的青花瓷标本作为代表,使用能量色散X射线荧光分析(EDXRF)、光学显微镜(OM)、X射线衍射分析(XRD)、拉曼光谱分析(Raman)和扫描电子显微镜-能谱分析(SEM-EDS)等方法,对污染物进行了研究,探讨了其形成原因以及环境的影响作用,并对其潜在危害进行了分析。研究表明,污染物主要以方解石、菱铁矿等碳酸盐以及铁的氧化物、氢氧化物和硫化物为主。长期处于河口淤泥中的还原性环境是导致菱铁矿和亚稳的铁硫化物形成的原因,船体中铁质构件腐蚀对局部环境的污染是重要的影响因素,这也反映出被污染的青花瓷所处位置和环境的特殊性。出水的部分青花瓷釉中裂纹的形态表明其形成是由物理撞击造成,而釉中硅灰石晶体的选择性腐蚀会导致腐蚀坑的形成,裂纹和腐蚀坑均为外部污染物进入釉层内部提供了通道,导致瓷器劣化。出水后... 相似文献
66.
中国保存有众多砖质文物建筑,目前这些文物多处于户外环境中,面临严重盐害导致的掏蚀损毁问题。因而,研究兼具脱盐功能的加固材料成为砖质文物等保护的一种创新思路,加固材料的研制和工艺技术的开发是其重点和难点,具有重大的社会需求和急迫性。为此,本工作从可溶性盐的破坏机制出发,研究出一种双组分无机加固材料,加固方法是Ba(OH)_2甲醇溶液与H_2C_2O_4、H_3PO_4乙醇溶液交替滴加,并模拟可溶性盐(NaCl、KCl、Na_2SO_4)分布的典型环境,进行加固、除盐,借助X射线衍射仪(XRD)、X射线荧光光谱仪(XRF)和无线阻尼抗钻仪等现代科学仪器,追踪盐的流出与转化过程。结果表明,本材料不仅能够加固模拟样品,同时能对最具破坏性的盐Na_2SO_4实现不可逆转化,生成重晶石的主要成分BaSO_4,加固与脱盐一次完成,是一种具有实际应用潜力的新材料。 相似文献
67.
微生物病害是出水木质古船面临的主要病害之一。其中,古船所处水/土环境中微生物的生长代谢或对古船产生直接危害,或通过改变古船所处环境进而影响文物安全,同时环境的改变也会反作用于微生物的群落结构和代谢特征。因此,环境和微生物构成相互影响的动态体系,系统、深入地研究两者之间的相互作用机制,及时发现风险甚至预测风险并采取科学有效的防治策略,是出水木质古船保护的重要方向。本研究采用环境监测结合现代分子生物学技术,对“长江口二号”古船出水前后的环境特征因子、微生物群落结构和潜在病害微生物进行分析。结果表明:“长江口二号”古船出水前后,水环境因子的变化幅度较大,水体微生物丰富度与多样性明显下降,尤其细菌丰富度大幅下降;沉积物环境因子的变化幅度比水环境因子的变化幅度小,同时微生物群落丰富度和多样性变化较小。沉积物和水环境中可参与降解木质素和纤维素的潜在病害微生物主要为芽孢杆菌(Bacillus)、曲霉菌(Aspergillus)和枝孢霉菌(Cladosporium)。此外,沉积物中存在比例较高的硫酸盐还原菌须引起关注。本研究初步建立了“长江口二号”古船环境因子-病害微生物监测评估方法体系,为后续通过科学化、系统化地积累基础数据进而采用统计分析和模型模拟手段评估甚至预测“长江口二号”古船的环境微生物风险状况奠定了基础。 相似文献
68.
《Romance Quarterly》2012,59(2):69-77
This article deals with the literary representation of three historical events—the battle of Trafalgar in 1805, Madrid's popular upheaval on 2 May 1808, and the siege of Cadiz in 1810—in six novels by Benito Pérez Galdós (Trafalgar, El 19 de marzo y el 2 de mayo, and Cádiz) and Arturo Pérez-Reverte (Cabo Trafalgar, Un día de cólera, and El asedio). The first part of the article focuses on narrative form and genre in each novel. The second part examines how the authors reflect on both the past and the future of Spain from a different perspective. Whereas Galdós in the 1870s still hopes for a political reconciliation that will lead his country to modernization, Pérez-Reverte in the 2000s is skeptical about the nation's social and moral progress. 相似文献
69.
本文以形制最具代表性的陶鬲为切入点,对罗山天湖商代墓葬出土陶器文化因素构成和墓葬葬俗进行了分析,认为罗山天湖商代墓葬与晚商殷墟类型存在明显差异,而这种差异也正是晚商中心文化势力衰落的一个表现形式。 相似文献
70.
R. Gillis R‐M. Arbogast J‐F. Piningre K. Debue J‐D. Vigne 《International Journal of Osteoarchaeology》2015,25(6):912-922
For cattle (Bos taurus), age estimations using dental criteria before the eruption of the first molar (3–8 months) have large error margins. This hampers archaeozoological investigation into perinatal mortality or the putative slaughtering of very young calves for milk exploitation. Previous ageing methods for subjuveniles have focused on the length of unfused bones, but it is rarely possible to use them because they are restricted to foetuses and because of the fragmentation of bones. This paper presents new age prediction models based on length, breadth and depth of post cranial bones produced from a dataset of modern calves (n = 27). This reference collection was compiled from material of known age at death, sex and breed from collections in Britain, France, Germany and Switzerland. Linear regression models were constructed using the modern data for age prediction, and these models were then successfully tested and assessed using a Middle Neolithic assemblage of complete calves' skeletons from Bourguignon‐Lès‐Morey, France. From the assessment, the astragalus and metapodials were determined to be the most reliable bones, and the femur was the worst. Measurements of the epiphyseal and distal elements and depth measurements were the most reliable. For ages before 12 months, these models can provide ±1 month age estimates. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献