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排序方式: 共有467条查询结果,搜索用时 15 毫秒
1.
浑仪、简仪(以下简称两仪)在高PH、大气污染和日晒雨淋环境中的腐蚀是一种动态加速腐蚀过程。采用合成的双唑胺铜缓蚀剂和有机硅改性的甲基丙烯酸树脂,并分别复配成协同缓蚀剂群和含有增效稳定剂的封护剂。采用这两种材料和脱水后再防护的工艺,使带锈防护后的浑仪、简仪的腐蚀低于无污染大气中的速率。用电化学方法评价了防护技术的可行性,根据腐蚀与人工老化试验结果讨论了防护材料性能与腐蚀环境和带锈防护的关系,采用XPS分析方法探索了双唑胺比BTA更适用于两仪防护的原因。  相似文献   
2.
Accurate simulation of multiphase flow in fractured porous media remains a challenge. An important problem is the representation of the discontinuous or near discontinuous behaviour of saturation in real geological formations. In the classical continuum approach, a refined mesh is required at the interface between fracture and porous media to capture the steep gradients in saturation and saturation‐dependent transport properties. This dramatically increases the computational load when large numbers of fractures are present in the numerical model. A discontinuous finite element method is reported here to model flow in fractured porous media. The governing multiphase porous media flow equations are solved in the adaptive mesh computational fluid dynamics code IC‐FERST on unstructured meshes. The method is based on a mixed control volume – discontinuous finite element formulation. This is combined with the PN+1DG‐PNDG element pair, which has discontinuous (order N+1) representation for velocity and discontinuous (order N) representation for pressure. A number of test cases are used to evaluate the method's ability to model fracture flow. The first is used to verify the performance of the element pair on structured and unstructured meshes of different resolution. Multiphase flow is then modelled in a range of idealised and simple fracture patterns. Solutions with sharp saturation fronts and computational economy in terms of mesh size are illustrated.  相似文献   
3.
卢梭的“自然美”思想丰赡深邃,精远宏阔.从美育目标、理念、重点三个层面梳理了卢梭自然主义美育思想的核心内容,将其教育特点归纳为整体性、平民性、情感性和自然性,并着重阐述了这一思想对新时期我国美育工作的四个重要启示:即注重美育工作的辩证性;尊重美育实践的主体性;激励美育过程的情感性;倡导美育内容的生态性.  相似文献   
4.
《隸續》載《米巫祭酒張普題字》全文,宋洪适對碑文作了綜述,云:"此碑有天師道法及祭酒、鬼兵字,而云受《■經》十二卷,蓋諸張妖黨指傳授之約,頗合史氏所載。"本文對"張普題字"以及該碑所在地作了分析。傳授之約或是祭酒向初入教的道徒傳授道家關於宇宙原始以及長生之道的基本觀念。此碑實是現存罕見的爲後人留下史籍未備的五斗米道入道儀式記録。  相似文献   
5.
Recognition and respect for sexual minorities in Hong Kong is still a contested area. Public sexual identity politics in Hong Kong has been framed by traditional Chinese gender ideology and imported Christian beliefs which are profoundly negative. Focusing on the interpersonal relationships in three spheres of life, the research adopted the sociological perspective of personal life and the feminist geographers’ idea of spatialization of identity management to analyze how the sexual self of sexual minorities has been marginalized and excluded in intimate social spaces of family, church communities and schools in Hong Kong with specific spatial practices and different forms of power/knowledge. By examining overlooked intimate injustice in personal life, this study illustrates that identity conflicts between Christianity and non-heterosexuality in everyday life is constructed through misrepresentation, misrecognition, harassment and exclusion in intimate relationships. Different types of knowledge are being used to reiterate pre-existing norms and institutionalized patterns of cultural value that constitute the sexual minorities as comparatively unworthy of respect. These micro-political processes involve both conformity and resistance to gender and sexual stereotypes. Participants managed to develop spatial coping strategies such as concealment, compartmentalization, confrontation and alternative sources of support to manage their lives with dignity and self-esteem.  相似文献   
6.
The quick and accurate identification of post-earthquake rescue objects can minimize the casualties and property loss caused by earthquakes. With the rapid development of remote sensing technology, rescue objects can be identified through high-resolution remote sensing images. There are two main categories of approaches to identify rescue object through high-resolution images: automatic extraction by a computer and visual judgment by professionals. Although results can be obtained quickly by using automatic extraction, the accuracy of the results is unacceptably low. For visual judgment, the large demands for time and professionals restrict its wide practical application. In this study, we introduce crowdsourcing into the identification of post-earthquake rescue objects. First, we integrate the advantages of the computer and crowdsourcing, which means that the computer takes advantage of the speed of information processing, while crowdsourcing makes full use of human recognition capabilities. Second, we take visual judgment tasks out of the hands of professionals and entrust the tasks to workers in a crowdsourcing platform. Not only are the human resources infinite, but we can also improve the efficiency of identifying rescue objects. Third, we propose a crowdsourcing model that improves the quality of the results and saves human resources. Finally, experimental results demonstrate that our solution is feasible.  相似文献   
7.
为了探索一种适宜的遗址文物保存方式,在四季分明,气候变化较为剧烈的西北地区的文物遗址环境区,达到最大程度保护遗址文物的目的,通过对开放式的秦始皇兵马俑博物馆一号坑遗址环境的建筑结构、温度和相对湿度变化及大气颗粒物进行分析监测,并与封闭式汉阳陵博物馆外葬坑的结果进行对比研究,发现单从环境温湿度恒定、阻挡室外颗粒污染物和气态污染物的角度来讲,封闭式的汉阳陵博物馆存在明显的优势。但依然不能阻止温湿度的季节间波动和室外空气污染物渗入的威胁,同时还要预防室内污染的发生,并且出现玻璃护围内部结露,文物大面积返碱等问题,并不能很好解决文物良好保存和观展目的。所以依旧需要探索一种适宜的遗址文物保存方式,既能保持文物保存环境的温湿度的相对稳定和洁净,又能缓解全封闭玻璃护围内部结露,文物大面积返碱等问题,最大程度延长遗址文物的寿命的同时,满足观众参观的需求。本对比研究结果可为今后的设计提供参考。  相似文献   
8.
Abstract

The author scrutinizes the history of Muli (木里) as a semiautonomous political entity in the 17th century southern Sino-Tibetan borderland. By tracing Muli’s improvization in the face of multiple powerful regimes such as the Naxi kingdom, the Geluk Tibetans, the Khoshut Mongols, and the Chinese dynasties, the author explores how an indigenous notion of power took shape in the wake of geopolitical turbulence. Before 1580, Muli was a colony of the Naxi kingdom and dominated by the Kagyu school of Tibetan Buddhism. After 1640, it became a stronghold of the Tibetan Buddhist Geluk school and was deeply involved in the power struggles between the Geluk and Kakyu schools as well as the Tibetans and Mongols. Despite of acknowledging multiple sovereigns, Muli rulers utilized various tactics to hold on to power and prioritize local interest. The nuanced, yet creative, strategies Muli people adopted showcases the significant role border regimes played and their agency in shaping the power dynamics in pre-modern Eastern Asian borderlands.  相似文献   
9.
The provenance of more than 2200-year-old terracotta warriors and horses in the Qin Shihuang Mausoleum is still a mystery, even though some researchers have inferred that the terracotta figures were produced near the mausoleum. The sporomorphs (pollen and spores) extracted from terracotta fragments of a warrior and a horse and compared with those obtained from soil samples from the Qin Dynasty layer in Pit No. 2 of the Qin Shihuang Mausoleum indicate that the pollen spectrum from the terracotta horse is different from that of the warrior, but similar to the local soil samples. Herbaceous pollen was dominant in the warrior sample, while arboreal pollen predominates in the horse and soil samples. Palynological evidence suggests that the terracotta horses were produced at a locality near the mausoleum, while the warrior came from a site which was further afield.  相似文献   
10.
黎虎 《史学月刊》2007,(3):19-27
"吏户"论所指的"吏"是行政系统的"吏",但是在具体论证时,却常常以军事系统的"军吏"——如"将吏"、"吏士"、"吏兵"、"武射吏"、"武吏"、"文武吏"等有关资料作为证据,这不仅将行政系统之"吏"与军事系统之"吏"乃至士兵混为一谈,而且根据这种资料所作出的论断就很难说是符合历史实际的。  相似文献   
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