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111.
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An investigation has been undertaken at St Andrew’s church, Walpole St Andrew, Norfolk, to establish the underlying causes of the observed stone decay to the upper parts of the six stone piers. The stone decay was first recorded in the early 1930s. The salt-contaminated masonry within the church has been shown to undergo severe salt decay during the summer, with little damage occurring over the winter months. The south aisle piers have been shown to decay 2.5 times faster than the north aisle piers. Although crystallization–hydration cycles have been identified, the rate of decay is at its greatest when the cycling is relatively infrequent. This was not the expected trend. Furthermore, it has been shown that during extended periods where the ambient relative humidity is less than 75%, the rate of decay reaches a maximum. It is the length of this ‘drying’ period that apparently has the greatest influence on the rate of decay and could explain the significant difference in the rate of decay between the south and north aisle piers. The results have serious implications for passive conservation, where it is often recommended to lower the ambient relative humidity to well below the equilibrium relative humidity of the salt contaminant, to avoid crystallization–hydration cycles. Since, at the time of building, the church was situated on the coast, it is possible that the sodium chloride contamination occurred during the building process (1440–1520), particularly since the area was prone to sea-flooding at this time. Alternatively, the salt could have been applied as a treatment during the general restoration of 1897. Whatever the source of the salt, it seems likely that the ambient environment was changed by the insertion of a sealed floor in 1897, which could account for the onset of the salt decay. 相似文献
113.
赛艇运动的项目特性及训练指导思想 总被引:13,自引:4,他引:9
通过对赛艇运动项目决定成绩的因素,如供能系统、专项素质、生理特性的分析,确定了赛艇运动的特性及规律,并据此特性科学地提出了该项目的训练指导思想. 相似文献
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对奥运会及我国大型运动会发行体育彩票融资的研究 总被引:1,自引:0,他引:1
当代大型运动会明显表现出对资金的高需求,但是目前各国中央政府的财政收入不足是各国政府共同面临的普遍问题,这将严重影响政府对大型运动会的投入,而发行体育彩票正是解决这一问题的主要手段之一.笔者就奥运会发行体育彩票的情况和我国举办大型运动会发行体育彩票的情况及存在问题作一论述,并对我国大型运动会通过发行体育彩票的融资提出建议. 相似文献
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Jajko P 《Medical reference services quarterly》1992,11(2):67-78
Information specialists should provide a value-added service by supplementing their online searches with primary research. Primary research results in more up-to-date information from a broader spectrum of sources. The requester benefits from primary research by receiving a cost-effective and more comprehensive information package. The information professional benefits by acquiring a more in-depth knowledge of the subject, increasing awareness of important projects within the organization, and achieving recognition as a key information analyst. 相似文献
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Jajko P 《Medical reference services quarterly》1992,11(1):63-66
Successful hospital and corporate libraries offer customized resources and services to meet the needs of their dynamic organizations. Concepts such as customer-driven, service-oriented and value-added are central to these libraries. Serving decision makers and integrating the library into the decision-making process of the organization is critical. Future articles in this new column will further explore the underlying philosophies and the specialized resources and services that characterize these libraries. 相似文献
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