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排序方式: 共有98条查询结果,搜索用时 15 毫秒
1.
四川省馆藏文物保存环境监测区域中心(简称四川区域中心)平台,经过两年多的运行实践,实现了12家博物馆监测站的集成联网。本研究分析了区域中心监测平台运行中常见故障现象的表现形式、故障原因及故障率。结果表明:监测平台的主要故障现象为传输异常和数据异常;除温湿度外的其他监测终端故障率较高;软件平台建设也不够完善,导致数据利用率低,尚不能实现风险评估、预测预警和预防调控等管理功能。针对分析发现的问题,提出一些相应的技术措施和管理措施,为有效降低故障的发生率,提升国内区域中心平台建设提供一定的指导和参考。  相似文献   
2.
Two sets of twelve Portland limestone tablets were attached to carousels outside and under the open, lightweight shelter at Bishop’s Palace (Witney, England) for 18 months to assess the influence of shelters on soiling and microbiological growth on stone. At the start, and at 6-month intervals, tablets were analysed using microscopy (optical and SEM), colour measurement (spectrophotometry), weight change measurement and salt content determination (ion chromatography). Concentrations of NO2 and SO2 were also monitored for a month using diffusion tubes. In addition, results were compared with those obtained by the UK National Materials Exposure Programme (NMEP) on chemical weathering rates. Differences in soiling and biological growth on sheltered and unsheltered samples, and their influence on limestone decay were established. The shelter is likely to reduce biological growth by modifying the micro-environmental conditions. However, it may also exacerbate dust deposition, which might increase decay rates in the long-term.  相似文献   
3.
Recent research has studied the effects of seasonal variability on waterlogged burial environments. In a new approach to the study of archaeological contexts, the use of controlled laboratory conditions via lysimeters has enabled new insights into the nature of short term fluctuations in saturation, and the impact that these can have on burial contexts. In addition, the protocols used have facilitated interesting insights into burial environments and the way in which fluctuations in saturation and seasonality can impact on the contained organic components within them.  相似文献   
4.
1992年以来我国城镇居民居住消费的变化趋势   总被引:3,自引:0,他引:3  
1992年之后,我国明确了建立社会主义市场经济体制的目标,城镇住房制度改革取得了实质性突破,城镇居民居住消费发生了深刻变化。居民购房公平自由,私有住房的比重急剧攀升,住房设施日益完善,居住环境不断优化,居住开支迅猛增长,城镇居民居住水平获得了前所未有的提高。然而受不正确的思想观念的影响,在居民居住消费过程中,一些诸如住宅私有率过高、住宅面积过大、一房伴终身等严重脱离实际需要和基本国情的问题日益突出。  相似文献   
5.
揭示家庭生命周期对旅游者行为的影响可以为家庭旅游精准营销提供依据.将城镇居民的家庭生命周期分为筑巢期、满巢Ⅰ期、满巢Ⅱ期、空巢期4个阶段,探究家庭生命周期对其旅游行为的影响,发现:①家庭生命周期影响旅游者的目的地选择行为,不同家庭生命周期旅游者的景区到访率距离衰减速率不同;②家庭生命周期影响旅游者的旅游活动类型偏好,满...  相似文献   
6.
In the prehispanic Gran Canaria there are some anthropological differences between the coastal inhabitants who buried their dead mainly in tumuli, and those from the central mountains, mainly buried in caves. Some data, as the prevalence of auricular exostoses, and a different bone Ba/Sr ratio support the view that there were differences in economy and diet between both groups of islanders. Moreover, the proportion of carious teeth was significantly higher among the population buried in caves. In the present study we analysed the prevalence of dental calculus, periodontal disease and antemortem tooth loss in remains of 791 individuals belonging to the anthropological collection of the Museo Canario (Las Palmas). Calculus deposition was very frequent (88.51%), no differences existing between men and women or between those interred in tumuli or in caves. Age at death was the only parameter independently related to calculus deposition by stepwise multivariate analysis. Periodontal disease was observed in 66.78% of the population, significantly more in men (χ2 = 4.88, P = 0.027). No differences existed between individuals buried in tumuli and in caves. Antemortem teeth loss was observed in 64.73% of individuals, no differences existing between men and women or between those interred in tumuli or in caves. There was a significant association between calculus and periodontal disease (χ2 = 18.07, P < 0.0001). Both caries (χ2 = 8.40, P = 0.004) and periodontal disease (χ2 = 44.96, P < 0.0001) were associated with tooth decay. However, the proportion of teeth with calculus deposition (in relation to observed teeth) was significantly higher among the population buried in tumuli (Z = 3.18, P = 0.001), although no differences were observed when the proportion of antemortem lost teeth and alveoli with periodontal disease were compared among people buried in tumuli and in caves, but women showed significantly lower proportions of alveoli with periodontal disease and antemortem tooth decay. These data suggest that the population buried in caves had a different dietary pattern to that of those buried in tumuli, since calculus deposition -more frequent in the latter-may be related to the consumption of proteins. The results also point to the existence of differences in diet between men and women.  相似文献   
7.
银元主币流通与上海洋厘行市的更替   总被引:2,自引:0,他引:2  
邹晓昇 《史学月刊》2006,3(8):36-42
墨西哥鹰洋成为近代中国流通最广的银元主币,历时长达60余年之久。1914年后开铸的袁世凯像新币,逐渐取代鹰洋成为流通中的主币。上海钱业公所和其后的上海钱业公会深谙流通中主币的消长变化态势,审时度势,先后于1915年和1919年取消龙洋和鹰洋行市。鹰洋行市的取消进一步促使国币通行成为主币,使货币兑换市场逐步走向统一,降低社会交易成本;同时也为废两改元准备了条件,促进了近代货币统一化进程。  相似文献   
8.
明代科举各级考试的规模及其录取率   总被引:2,自引:0,他引:2  
郭培贵 《史学月刊》2006,(12):24-31
明中叶后,各省直的科考规模在四五千人至数万人之间,平均录取率估计在10%上下。乡试录取率,明初一般在10%上下;成、弘间定为5.9%;嘉靖末年又降为3.3%;而实际录取率又低于此。会试录取率,自洪武至万历中平均为8.6%;其中,洪武至永乐二年平均为21.7%,永乐四年至万历中期平均为8.4%。殿试规模和录取数在理论上皆等于同科会试录取数。永乐二年后,明廷共在51科14938名二、三甲进士中考选了1277名庶吉士,平均录取率为8.55%。上述录取率,都是在朝廷调控下形成的,并非完全自由竞争的结果。而之所以进行调控,又是由官缺的有限性和科举取士用途的单一性矛盾造成的。  相似文献   
9.
A noted specialist on the Russian economy presents an assessment of the impact of the global financial crisis on the mechanism of the country's economic growth. Focusing on the demand side of the economic ledger, the author explores the question of whether Russia will be able to re-attain the high economic growth rates of the period from 2000 to 2007 after recovering from the crisis. The paper analyzes the sharp drop in production in 2008 and the first quarter of 2009, attributing most of the damage to liquidity problems and declines in the price of oil. Empirical evidence is based primarily on data collected by the author from the Central Bank of Russia and the country's federal bureau of statistics (Rosstat). Journal of Economic Literature, Classification Numbers: E010, E200, E660, F210, G010. 11 figures, 3 tables, 29 references.  相似文献   
10.
A noted American authority on China's economy and monetary policy presents a statistical as well as theoretical analysis of a variety of perspectives on the controversy surrounding China's currency, basing his paper on both. The author provides the historical background and comprehensive summaries, focusing on different viewpoints about whether China's currency is undervalued, and thus may contribute to global imbalances. In the paper, he divides observers involved in the controversy into two main camps, namely the ones who find China's trade balances to be sensitive to price effects through exchange rate adjustments and those who emphasize other factors as bearing the responsibility for China's large surpluses, including the U.S. credit bubble emerging before the global financial crisis, as well as a version of Dutch disease.  相似文献   
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