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71.
左江流域水土流失现状与治理措施   总被引:3,自引:0,他引:3  
左江流域包括扶绥、崇左、宁明、龙州、凭祥、大新六县市,位于南宁地区的西南部。由于长期以来不合理的开发利用,致使水土流失现象十分严重,不但有面蚀、沟蚀,有些地方甚至发展成崩岗。该区域总面积15092.39Km2,水上流失面积525.81Km2,本文在分析水土流失现状及成因的基础上,提出相应的水土保持措施。  相似文献   
72.
为弥补我国南方潮湿地区壁画保护材料研究的欠缺,模拟南方气候条件对壁画表面加固和裂隙灌浆材料进行保护效果的评价研究。通过前期预实验以及表面光泽度、防水性、耐老化性等测试评价得到:质量分数1.5%的RS1930纯丙乳液具有较好的表面加固效果;传统石灰中添加占石灰质量3.0%左右的ZB-SE-3A纯丙乳液和2.0%左右的纳米材料配制而成的灌浆材料具有较好的强度、防霉性、防水性与耐老化性,适合作为潮湿地区壁画灌浆加固材料。  相似文献   
73.
激光清洗作为一种新型清洗技术,具有高效、安全、可控等优点。本研究使用激光清洗技术对壁画样品表面污染物进行清洗试验。通过模拟样块试验确定激光清洗设备的损伤阈值与清洗阈值;然后在损伤阈值与清洗阈值范围内,根据不同污染物采用不同的激光能量密度和辅助手段,对壁画样品进行激光清洗试验,最终确定有效的设备参数;在激光清洗同时使用显微镜和色度仪进行清洗效果评估。清洗试验证实激光清洗技术可有效清理部分壁画表面污染物,并确定部分有效参数,为实际工作提供参考和借鉴。  相似文献   
74.
河南信阳城阳城遗址M8为高等级战国晚期楚国贵族墓,该墓出土了以漆木器为主的各类文物400余件,其中尤以黑、红两色竹蔑编织而成的髹漆竹席最为精美。为开展彩漆竹席脱水保护提供基础数据,采用激光共聚焦显微镜、拉曼分析仪和傅里叶红外吸收光谱仪(FTIR)及扫描电镜-能谱(SEM-EDS)等现代分析仪器对竹席漆膜的成分及表面形态进行了分析,并在此基础上,结合传统髹漆文献资料探讨了漆膜的制作工艺。结果表明:城阳城彩席中的黑色漆膜为大漆自然显色,红色漆膜是大漆掺加朱砂调制而成;黑色漆膜表面较为平整,漆膜与胎体结合紧密,红色漆膜表面相对粗糙,结构较为疏松;竹席漆膜的厚度在0.02~0.03 mm之间,应是由大漆涂刷至少3~5次制备而成。研究结果可为下一步的彩漆竹席的脱水保护及展示提供基础数据。  相似文献   
75.
Abstract

This paper will present research on the vulnerability mapping of coastal archaeological sites currently being undertaken in Northern Ireland. The ultimate aim of this research is improve current predictions of where archaeological sites and landscapes will be at risk in the future from coastal erosion. The initial stage of this approach uses a suite of oblique aerial photographs to construct a baseline of eroding locations and coastal geomorphology. The erosion baseline can then be integrated with existing historic environment records to obtain a coarse first-pass archaeological vulnerability assessment. Subsequent stages can then use this assessment to prioritize future mitigation such as field surveys or monitoring exercises, or conduct further refinements of vulnerability classifications by incorporating information on site type and positioning on a local scale.  相似文献   
76.
This article deals with evaluation of the seismic vulnerability of a high-voltage vertical disconnect switch, one of the most vulnerable elements of electric substations. The main objective of the research is to evaluate the seismic fragility of the apparatus using a new effective method. By combining standard reliability methods for time-invariant problems with the response surface technique, this original procedure called “EFA” (Effective Fragility Analysis) permits the evaluation of fragility curves using a very limited number of numerical simulations. On the basis of experimental tests, to determine the mechanical characteristics of the disconnect switch components (ceramic, joints, etc.) the fragility curves of the equipment analyzed are carried out. The results are discussed and compared with the results of Monte Carlo simulations, which confirm the reliability of the procedure.  相似文献   
77.
This article presents the effects of sediment-damping, impedance-contrast (IC), and size of semi-spherical (SS) basin on the focusing and trapping of the basin-generated surface (BGS) waves and the spatial-variation of average-spectral-amplification (ASA), differential ground motion (DGM), and average-aggravation-factor (AAF). A frequency-dependent focusing of the BGS-wave is inferred. Increase of ASA, DGM, and AAF with increase of size of the SS-basin with a fixed-shape-ratio revealed that the BGS-wave focusing has counter-balanced the sediment-damping effects. It is concluded that the BGS-wave focusing and trapping in the SS-basin is more sensitive to change of IC as compared to the similar change of sediment-damping.  相似文献   
78.
The bas-relief carved on the sandstone wall in the central part of the inner gallery of Bayon in the Angkor monuments, Cambodia, has been severely damaged mainly due to calcite crystallization. In order to confirm the mechanism of salt weathering and help determine conservation measures for the bas-relief, measurements of the annual change in the moisture content in the bas-relief were conducted. We found that water supplied from the platform behind the bas-relief is the cause of calcite crystallization. It is therefore indispensable for the conservation of the bas-relief to prevent the water permeating from the inside of the platform behind it. As precipitated calcite from the water block pores near the surface of the sandstone, the surface water absorption test is a useful method to evaluate the degree of the salt weathering.  相似文献   
79.
表面强度是夯土遗址重要的测试指标和加固效果的评价依据。常规的强度测试方法受到取样和运输等因素的制约,不适用于作为夯土遗址如夯土补筑、表面加固等措施的效果评估方法。贯入法是成熟的砂浆强度检测方法,通过改装砂浆贯入仪降低了仪器量程;制作夯土样、室内试验验证了测试的较高精度;标定了夯土样贯入深度测量值与抗压强度的幂函数关系,确定了测强曲线。在夯土遗址现场开展原位测试,分析了布点密度对测试结果精度的影响,并利用测强曲线推算了测试区域的表面抗压强度。本研究提出了一套集“仪器改装-室内标定-现场高密度布点测试”为一体的夯土遗址表面强度评估方法,为土遗址加固效果的评价体系建设提供了参考价值。  相似文献   
80.
The discovery and excavation of superimposed, information-rich Pre-Boreal hunting sites around the mountain lakes of Myrvatn and Fløyrlivatn in Southwest Norway have been the subject of archaeological debate. A brief review of research is presented here. In contrast to the well-preserved sites, settlement remains of a diametrically different order occur in the strongly water-eroded zone of the lakeshores: small, surface hearths in almost every stage of preservation, from evident hearths to diffuse and irregular scatters of fire-cracked stones. The latter category seems generally underestimated as a source of evidence. However, recent finds at Myrvatn demonstrate how even blurred, heavily eroded and almost intangible hearth remains, by the support of wood anatomical analysis, radiocarbon dating and intra-site comparison, may reveal concise, invaluable information both about the history of local use and regional landscape development.  相似文献   
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