排序方式: 共有213条查询结果,搜索用时 15 毫秒
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以净初级生产力作为生态系统服务的综合测量指标,在经典柯布道格拉斯生产函数的基础上,运用协整与误差修正模型对1986-2010年黑龙江省生态系统服务对区域经济增长的影响进行了分析,并评估了净初级生产力的边际价格。结果表明,黑龙江省生态系统服务对区域经济增长具有明显的促进作用,净初级生产力每提高1%促进真实GDP增长0.0257%;在生态系统服务的影响下,黑龙江省经济系统以每年1.8%的速率将系统波动产生的非均衡状态向长期均衡状态调整,说明生态系统服务在促进经济增长的同时也保障了经济体系的稳定运行;在误差修正模型基础上得到的黑龙江省净初级生产力的边际价格为255.1元/106kgC(以1952年价格为基准),此价格主要受净初级生产力产出弹性的影响。 相似文献
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魏乐 《文物保护与考古科学》2022,34(1):10-19
以红花染纺织品作为主要研究对象,通过紫外光和LED两种光老化方式,研究不同褪色因素影响下纺织品中显色组分红花苷的降解变化情况,实验发现不同酸化作用对红花苷造成不同的影响。采用液相色谱质谱联用的方法,鉴定出红花苷、芹菜素等多种组分,并首次从红花中鉴定出国外报道的但一直未确定的组分Ct4的分子结构,实际是三香豆酰亚精胺,一种酚酰胺类化合物,可作为一种染色工艺指标对现代染和古代染色工艺进行区分。以故宫院藏两件红花染褪色纺织品文物为例阐述褪色机理,显色组分红花苷的降解,产生不同程度的裂化产物小分子,使原本微量存在的三香豆酰亚精胺相对含量增高,从而造成褪色明显,文物在长期日晒下正面原本红色外观呈现橘色打底。同时强调了博物馆应高度重视相同类型文物保存环境中的挥发性酸性气体监测。 相似文献
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Mengjun Jia Guofeng Wei Celestino Grifa Jianhui Zhang Biao Cui Min Li Jun Xu Xiao Ma 《Archaeometry》2023,65(4):736-753
Lime mortars have played an important role in constructing ancient Chinese masonry structures, including city walls, buildings, and tombs. A tomb built with lime mortars and stones belonging a Ming high-ranking official, Xu Jie, was discovered in Huzhou City of China. Eight different samples from Xu Jie’s tomb, representing four types of lime-mortar-based materials: joint mortar between stone bricks, bedding mortar, grouting mortar, and plaster mortars were collected for analysis and comparison. The characterization of the construction materials has therefore become of primary importance. The function of each mortar was reported and studies into the micro-textural features and mineralogical compositions of those mortars were performed via a multi-analytical approach. The joint mortars were all found to be aerial lime mortars with predominately lime. The bedding mortar was found to consist of lime, soil and sand, typical of a tabia mortar. The grouting mortar was found to consist of lime and ground contact metamorphosed limestone. Analysis of plaster sample taken from the roof of the main tomb identified the presence of calcium stearate/palmitate, indicating the usage of plant-based tung oil as an additive. The analytical results will promote our understanding of Ming architectural technology and craftsmanship, and provide critical information for the conservation of Xu Jie’s tomb. 相似文献
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区域是一个开放的复杂巨系统,系统科学的方法论对区域发展研究产生了重要的影响。本文对区域发展研究中采用的系统科学方法进行了回顾和总结,重点探讨了钱学森先生20世纪90年代首次提出的"综合集成研讨厅"体系在当代区域发展研究中的应用,并对其组织结构及实施原则进行了讨论。 相似文献
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从深圳市举行的一次城市道路规划听证会,引发出对城市规划诉讼特性的思索。通过将城市规划的一些基本属性与法理结合起来分析,认为城市规划成果以及城市规划制定有着不可诉的特性。依照我国目前的国情,应提倡城市规划不可诉,这将有助于促进城市规划的立法创新和公众参与。 相似文献
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旅游目的地推广与影视旅游研究 总被引:4,自引:0,他引:4
在现代科技和经济全球化迅猛发展的背景下,新的旅游目的地推广方式影视旅游随之产生。影视旅游之所以成为目的地推广工具,电影电视中出现的相关旅游地的旅游形象在其中起了重要作用,它影响了旅游者的旅游兴趣,最终促成旅游行为。本文在现有文献理论和实证研究的基础上,探讨了影视旅游推广的原理和如何运用影视旅游作为目的地推广工具,最大化推广旅游目的地,最终使得旅游目的地在竞争中占据有利地位,实现利益最大化。 相似文献
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为重建馆藏青铜器香薰三维模型和研究其制造工艺,利用高精度计算机断层扫描系统进行数字成像(DR)和锥束扫描(CT)两种方式扫描香熏,获得其灰度图像,经过图形图像处理,获取表面轮廓三维数据。表面定义和提取后,将数据输入逆向工程软件系统,重建香熏的三维CAD模型。结果表明,获得的点云数据密集均匀,未见扫描盲区;发现香熏存在焊孔和变形;逆向三维重建的香熏CAD模型具有良好的几何相似性。研究提示,高精度计算机断层扫描方法空间分辨率高,精确度高,可以作为一种获取青铜器三维数据的可靠方法。 相似文献
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The earliest noodles have been dated to 4000 years ago, based on the discovery of remains at Lajia in north western China. The Lajia noodles were described as having been made by repeatedly stretching dough composed of millet flour with husks. In order to try to understand this manufacturing technique we carried out simulation experiments in noodle‐making and documented morphological changes in noodle starches caused by cooking. Our research demonstrates that it is impossible to stretch pure millet dough into noodles. We conclude that the husk phytoliths and starch‐like granules said to be from the Lajia noodle remains may actually not have been part of the noodles themselves. 相似文献
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