Environmentally-induced stone decay: the cumulative effects of crystallization–hydration cycles on a Lincolnshire oopelsparite limestone     

Belinda J. Colston  David S. Watt  Helen L. Munro   《Journal of Cultural Heritage》2001,2(4)

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   

普通高校实施《学生体质健康标准》的实践与思考     

陈华 《浙江体育科学》2006,28(4):43-46

运用比较研究法,通过杭州电子科技大学实施《学生体质健康标准》的实践,结果表明:男女学生身高随着年级递升略有下降,男生体重随着年级递升而逐渐增加,女生体重随着年级递升而逐渐下降,男女学生较低体重率明显高于体重正常率,低年级学生心血管机能水平明显好于高年级,二年级男生和四年级女生肺功能水平较好;男女学生下肢爆发力、男生柔韧性和女生前臂力量的峰值出现在二年级;并对身高标准体重的评价标准进行思考。  相似文献   

基于Jess规则的数据库通知服务   总被引：1，自引：0，他引：1  

胡勤友施朝健  陈海山危强 《上海海事大学学报》2006,27(1):44-48

提出一种实现数据库通知服务的技术框架,使用Jess规则代替SQL编码来表达用户的数据监控策略,规则执行时先由规则解释器将规则翻译成SQL语句然后执行.使用这种方法,数据监控策略易于理解和接受,修改方便;其次,可在规则解释器中实现异构数据库系统之间的关联通知服务;最后,Jess规则还可以进行复杂的推理,实现通知业务的智能化.  相似文献   

Oddy Test Reloaded: Standardized Test Equipment and Evaluation Methods for Accelerated Corrosion Testing     

Hildegard Heine 《文物保护研究》2018,63(5):362-365

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Particle Penetration,Emission and Deposition in the Diocesan Museum in Udine,Italy to Assess Soiling of Giambattista Tiepolo’s Wall Paintings     

Chiara Bertolin  Marcin Strojecki  Roman Kozłowski 《文物保护研究》2018,63(5):326-328

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银行监督、利率管制与中小企业融资   总被引：1，自引：0，他引：1  

刘宇光 《徐州师范大学学报(哲学社会科学版)》2005,31(3):85-88,92

自有资金较少的中小企业只有在受到监督的情况下才能得到贷款。而监督需要成本,在监督成本较高的情况下,银行就不愿意发放监督贷款,中小企业就很难得到融资。只有进行利率市场化改革和降低监督成本,才能解决中小企业融资难的问题。  相似文献   

八段锦竞赛功法对大学生机体自由基代谢和身体形态影响的研究     

李秋平  刘毅  彭婵  陈阳阳  任建立 《湖北体育科技》2016,(5)

目的:探索健身气功·八段锦(竞赛功法)对大学生机体自由基代谢和身体形态的影响。方法:主要采用实验法,随机抽取2014级康保系男生和女生各20人,持续进行4个月的功法习练,观察血脂和生理机能的变化。结果:大学生经过4个月的功法习练后,3个时间点测试SOD、CAT和大腿围指标呈上升趋势,MDA、XOD和腰臀比指标呈下降趋势,差异具有统计学意义;测试体重、体重指数和大臂围3项指标没有显著性差异。结论:健身气功·八段锦(竞赛功法)对大学生机体脏腑、固肾壮腰、提振精神、防治疲劳、改善血液循环、提高腰腹柔韧和腿部力量等方面有重要帮助。  相似文献   

Validity of Self-Reported Pedometer Steps per Day in College Students     

Brittany Star Overstreet  Scott E. Crouter  George A. Butler  Cary M. Springer  David R. Bassett 《Measurement in physical education and exercise science》2016,20(3):140-145

The purpose of this article was to examine the validity of self-reported pedometer steps/day. Forty-seven participants were provided a New Lifestyles NL-2000 (NL-2000; Lees Summit, MO, USA) pedometer and a physical activity (PA) diary for 3 weeks, but not informed of the data-storing capabilities. For weeks 2 and 3, each participant was given a step goal of 3,000 steps/day above week 1 average. A 2 × 3 repeated measures analysis of variance (ANOVA) was used to examine differences between reported steps/day. Bland–Altman plots assessed the mean bias and limits of agreement between reporting methods. Mean self-reported and NL-2000 steps/day were 9,264 ± 3,555 and 8,971 ± 3,590 steps/day (n = 26, p > .05). Mean biases were 216 ± 1,753 (week 1), –506 ± 1,355 (week 2), and –590 ± 1,360 (week 3) steps/day. Negative mean bias values indicate higher self-reported steps/day. Mean steps/day were similar between recording methods, but large differences were observed among individuals, suggesting self-reported steps/day may be valid for PA research at the population level, but not the individual level.  相似文献   

多元学校问责:OECD国家教育治理的新趋势     

张雅慧  王阳  唐汉卫 《比较教育研究》2019,41(8):86-91

21世纪以来,受教育权力分散化、市场机制、参与式民主以及绩效问责不足等内外因素的影响,多元学校问责日益成为OECD国家教育治理的新兴方式。多元学校问责是指多个主体根据学校提供的数据和信息资源等对学校进行全方位监测,以促进学校教育质量的改善与提升。多元化的问责主体、多样性的问责方式、横向性的问责机制是多元学校问责的显著特征。在推进现代教育治理体系化背景下,多元学校问责已成为OECD国家基于各自国情而展开的一种实践方式,而精准识别利益相关主体、协调利益相关者之间的权力以及提高学校管理者的领导力也已然成为OECD国家有效实施多元学校问责的重要经验。  相似文献   

导学教师对学生学习监控的探讨     

吉云辉 《山西广播电视大学学报》2006,11(2):65-66

在开放教育教师与学生在时空上准分离的情况下,对学生学习过程的有效监控十分困难,为此,试图从导学教师对学生学习过程监控入手,就监控的标准、内容、途径等问题做一探讨。  相似文献