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31.
LIU Xiangwen YANG Guangming ZOU Huamin QU Jing & ZHAO Wenxia . Graduate School China University of Geosciences Wuhan China . Test Center China University of Geosciences Wuhan China . Physics Technology College Wuhan University Wuhan China . Test Center Zhongshan University Guangzhou China 《中国科学D辑(英文版)》2004,47(3)
Sakhaite was first discovered by Ostrovskaya, Pertsev and Nikitina at Siberia in the former Soviet Union. By using the X-ray diffraction technique, they proved that the crystal system of sakhaite was cubic (a = 1.464 nm), its possible space groups were Fm3m, F432, F43m, Fm3, F23, and its crystal chemical for-mula was Ca48Mg16(CO3)16(BO3)28Cl4(OH)8 4H2O[1]. Chichagov, Simonov and Belov studied the crystal structure of synthetic sakhaite and determined that its space group was F4132, … 相似文献
32.
均匀色空间中绿色翡翠的色差 总被引:7,自引:0,他引:7
采用MPV-Ⅲ型显微光度计测定了32个翡翠样品的可见光吸收光谱,计算了部分样品的三刺激值。在此基础上引入色度学中均匀色空间及色差的概念,通过计算样品NBS值定量分析了不同翡翠样品间的绿色差异。结果表明,色差的定量计算可以反映样品间的真实颜色差别,并且不同于同色异谱指数,可作为绿色翡翠颜色鉴别中一种较为有效的定量方法。 相似文献
33.
South Africa’s cities have experienced dramatic changes over the past decade. Cities are now home to a multiracial population, and have been transformed by new forms of economic and social interaction. For some, these changes have become a significant source of fear and anxiety. In this paper, we examine reactions to urban spatial change in the city of Durban, as expressed in local newspapers and interviews with suburban residents. We describe how the discourses of urban change in Durban have centred on the increased presence of street traders within the city’s public spaces, and the various ways in which the activity of street trade has disrupted long-established modernist norms governing the occupation and use of the urban space. Specifically, we offer a detailed reading of three prominent narratives within the discussion of street traders in Durban--chaos, congestion and pollution. We argue that street traders have come to embody a wide range of more deeply seated cultural anxieties, which have been brought to the fore in the context of South Africa’s transition. These anxieties arise from the ways in which modern understandings of order, agency and subjectivity have been called into question by material changes in the city, and have implications for the nature of citizenship and civic engagement in post-apartheid South Africa. 相似文献
34.
Kirsten Simonsen 《Geoforum》2004,35(5):525-528
This intervention address some of the social and epistemological mechanisms that construct an `international' writing space imbued with an Anglo-American hegemony. This is done by way of three examples, each making it possible to infer one of the general mechanisms at work. Taking off from the, comment, by the way of examples from Denmark, tries to illustrate how a truthful acknowledgement of the contextuality of geographical knowledges can multiply the spaces of critical geography--in the end enriching Anglo-American and non-Anglo-American debates alike. 相似文献
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The high-altitude dayside cusps (both northern and southern) are extremely dynamic regions in geospace. Large diamagnetic cavities with significant fluctuations of the local magnetic field strength have been observed there. These cusp diamagnetic cavities are always there day after day and are as large as 6 RE Associated with these cavities are charged particles with energies from 20 keV up to 10 MeV. The intensities of the cusp energetic ions have been observed to increase by as much as four orders of the magnitude when compared with regions adjacent to the cusp which includes the magnetosheath. Their seed populations are a mixture of ionospheric and solar wind particles. The measured energetic ion fluxes in the high-altitude cusp are higher than that in both the regions upstream and downstream from the bow shock. Turbulent electric fields with an amplitude of about 10 mV/m are also present in the cusp, and a cusp resonant acceleration mechanism is suggested. The observations indicate that the dayside high-altitude cusp is a key region for transferring the solar wind mass, momentum, and energy into the Earth’s magnetosphere. 相似文献
37.
本文以长沙市中医医院的方案设计为例,对如何利用自然环境划分、组织建筑空间以及结合当地人文、地理环境塑造合理的建筑造型进行了详尽的描述。 相似文献
38.
通过潍坊中医院综合楼的方案设计,探讨了现代医院设计的发展趋势-把人的需求放在首位,既为病人也为医护人员服务,打破过去仅以技术科学为出发点的格局. 相似文献
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40.
随着地下空间资源的开发利用,越来越多深基坑呈现出开挖深、规模大、形状不规则等特点,其支护结构设计复杂,施工难度大,具有明显的空间效应。本文以南京地铁某基坑工程为例,分析基坑施工对邻近桥梁的影响。其场区位于长江下游漫滩相二元结构地层分布地段,上部软土层厚度大,下部承压含水层地下水位高、水量丰富,地质条件复杂,该基坑为典型的深大异形基坑,距离某大桥的双曲拱引桥仅为7. 2 m,由于之前桥梁已遭受其他地下工程施工产生的较大变形,所以后续工程对其影响变形控制要求极高。为此,该车站基坑支护结构设计基于地下空间实际功能采用设置分隔墙分区开挖及MJS超深工法墙综合变形控制方案。本文通过有限元数值模拟计算,开展复杂环境下基坑开挖引起的围护结构及桥梁桩基的变形预测分析,计算结果显示,该深大狭长异形基坑开挖对邻近桥梁沉降变形影响显著,通过设置分隔墙分区开挖及MJS工法墙进行变形控制,能够较好地控制基坑的空间效应,减少“长边效应”、“异形效应”等对桥梁沉降变形的影响。通过现场基坑开挖过程实际监测结果,验证这一综合变形控制方案的可行性。该研究成果对于类似复杂地质条件下深大狭长异形基坑的支护及施工设计具有很好的借鉴意义。 相似文献