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51.
The microclimatic analysis of the Petrarca's tomb in Arquà Petrarca, Padua (Italy) was performed to assess the suitability of a closed environment located outdoors respect to the conservation requirements of heritage materials. Results showed that the thermo-hygrometric conditions inside the tomb were not suitable for the conservation of organic materials, like bones and wood. The orientation (north or south) was the main responsible for the different damage features of the two sides of the wooden case housing the human remains inside the tomb. Technical solutions were finally implemented to improve the conservation conditions, thus avoiding further damage.  相似文献   
52.
结合足球专项运动的特点,运用生化学原理分析足球运动员的专项有氧能力,对目前大多数学者所认同的足球运动员的专项有氧能力是速度耐力不够的观点提出了不同看法。并根据足球专项运动能量代谢特点,提出了专项有氧能力的训练方法。  相似文献   
53.
本文结合《有机化学》课程自身的特点,从多媒体内容的选择、实施方式、注意事项等方面,就MOOC时代,如何更好的发挥多媒体辅助课堂教学的作用,从而提高有机化学的教学效果进行了思考。  相似文献   
54.
Cellulose nitrate was widely used as a film base for photography, cinematography, and radiography in the first half of the twentieth century. Its stability is inherently poor and subject to environmental storage conditions. The risk of fire and the cross-infection effect on the cellulose acetate film stored at the same location necessitate that cellulose nitrate is identified within collections and stored separately. Not only medical archives, but also museums using radiography in their research may hold a sizeable amount of historical X-ray films. The Natural History Museum, London has been using film for X-radiography since before World War II. This suggests that some of the X-ray materials in its collections have a cellulose nitrate rather than ‘safety’ (cellulose acetate or polyester) film base. X-ray sheets rarely contain information related to their composition so science-based identification methods must be used. We propose the determination of nitrogen content in the film by organic elemental analysis (OEA) as a reliable method for the identification of films (X-ray, photographic, or cinematographic) with a cellulose nitrate base. Though it is a destructive method, the sample size required is small (<1?mg). This method does not require any sample preparation apart from weighing the samples and wrapping them in tin foil. OEA proved to be more accurate than the ‘float’ test in trichloroethylene and quicker and more straightforward to perform than infrared spectroscopy.  相似文献   
55.
Air pollution is one of the environmental influences that degrade cultural heritage objects situated indoors. Other essential influences, such as temperature, relative humidity, and light are often well monitored. The presence of air pollutants is less often measured or included in risk assessment. The MEMORI® technology presented in this paper was developed as a tool for easy measurement and assessment of the general risk of degradation of heritage objects situated indoors due to indoor exposure to air pollutants. MEMORI dosimetry was performed in locations belonging to English Heritage and Tate (both located in London) and the National Archives of Norway in Oslo, to assess air quality. The related damage risk for collection objects and the protection offered by display and storage designs was assessed. A high level of acidic effect was observed inside a number of showcases, and a high level of oxidizing effect was observed in some room locations. Relatively simple mitigation measures, such as constructing tightly sealed showcases using low emitting materials, installing active carbon absorbing media inside a ‘microclimate’ frame, and using cardboard storage boxes for paper, significantly improved air quality. Overall, implementation of such measures is likely to improve the preservation of objects and reduce conservation costs.  相似文献   
56.
论述了在有机合成中选择控制的重要性,结合教学实践归纳总结了各种选择控制的策略和办法。  相似文献   
57.
58.
Manghan Faulted Sag is an exploratory target area in Kailu Basin. In order to determine its exploration prospect, the effectiveness of its source rocks is evaluated by organic geochemical behavior analysis of the samples, and their distributions are predicted using trace integration seismic inversion technology. Studies on their organic matter abundance, type and maturity indicate that the source rocks in the Sag have great generating potentials. Furthermore, it is found that, based on the spatial distribution predication, the source rocks in the Sag are well developed. Therefore, the Sag has a promising prospect for exploration.  相似文献   
59.
利用透析方法将不同时间点收获的富铬决明子芽中的有机铬和无机铬分开,用石墨炉原子吸收分光光度法测定富铬决明子芽中的总铬含量和无机铬含量,计算出各时间点收获的决明子芽的有机铬转化率。探讨决明子生芽转化有机铬的效果。培育时间对决明子芽有机铬转化率有一定影响,在本实验条件下,72h是培育富铬决明子的适宜时间段。  相似文献   
60.
本文介绍了食品科学专业硕士研究生有机合成课程教学改革的几点体会,包括教学内容的掌握、教学形式的多样化、练习环节的探索及考试形式的选择等内容。  相似文献   
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