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高水压作用下井壁混凝土强度发展趋势
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作者 薛维培 姚直书 +2 位作者 李必达 徐进 金冬 《中国科技论文》 CAS 北大核心 2017年第1期91-94,共4页
为了探究高强高性能井壁混凝土在高水压作用下强度发展趋势,配制了C70、C80这2种强度等级井壁混凝土,并根据养护条件不同将每种强度等级的混凝土分为密封状态试件和常规状态试件,研究4、6、8、10 MPa这4种水围压作用下混凝土试件三轴峰... 为了探究高强高性能井壁混凝土在高水压作用下强度发展趋势,配制了C70、C80这2种强度等级井壁混凝土,并根据养护条件不同将每种强度等级的混凝土分为密封状态试件和常规状态试件,研究4、6、8、10 MPa这4种水围压作用下混凝土试件三轴峰值强度变化情况;同时采用Richart线性强度准则和Newman非线性强度准则对试验结果进行拟合。结果表明:水围压作用下混凝土试件三轴峰值强度较单轴抗压强度有较大提高,其中密封状态混凝土试件水围压增强效应更大,且随着混凝土强度等级提高,常规状态混凝土试件三轴峰值强度提高系数有所减少;Newman非线性强度准则拟合精度更高,说明高水压作用下井壁混凝土强度呈非线性发展趋势。 展开更多
关键词 井壁混凝土 高水压 三轴峰值强度 强度发展趋势 非线性
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Century-long variability and trends in daily precipitation characteristics at three Finnish stations 被引量:5
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作者 Masoud IRANNEZHAD Hannu MARTTILA +1 位作者 Deliang CHEN Bj?rn KL?VE 《Advances in Climate Change Research》 SCIE CSCD 2016年第1期54-69,共16页
Long-term variations and trends in a wide range of statistics for daily precipitation characteristics in terms of intensity, frequency and duration in Finland were analysed using precipitation records during 1908e2008... Long-term variations and trends in a wide range of statistics for daily precipitation characteristics in terms of intensity, frequency and duration in Finland were analysed using precipitation records during 1908e2008 from 3 meteorological stations in the south(Kaisaniemi),centre(Kajaani) and north(Sodankyl€a). Although precipitation days in northern part were more frequent than in central and southern parts, daily precipitation intensity in the south was generally higher than those in the centre and north of the country. Annual sum of very light precipitation(0 mm < daily precipitation long-term 50 th percentile of daily precipitation more than 0 mm) significantly( p < 0.05) decreased over time,with the highest rate in northern Finland. These decreasing trends might be the result of significant increases in frequency of days with very light precipitation at all the stations, with the highest and lowest rates in northern and southern Finland, respectively. Ratio of annual total precipitation to number of precipitation days also declined in Finland over 1908e2008, with a decreasing north to south gradient. However, annual duration indices of daily precipitation revealed no statistically significant trends at any station. Daily precipitation characteristics showed significant relationships with various well-known atmospheric circulation patterns(ACPs). In particular, the East Atlantic/West Russia(EA/WR)pattern in summer was the most influential ACP negatively associated with different daily precipitation intensity, frequency and duration indices at all three stations studied. 展开更多
关键词 Daily precipitation characteristics Trend analysis Intensity Frequency Duration EXTREMES Atmospheric circulation patterns FINLAND
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Carbon Emission Trends of Manufacturing and Influencing Factors in Jilin Province,China
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作者 YU Chao MA Yanji 《Chinese Geographical Science》 SCIE CSCD 2016年第5期656-669,共14页
This paper constructed a carbon emission identity based on five factors: industrial activity, industrial structure, energy inten- sity, energy mix and carbon emission parameter, and analyzed manufacturing carbon emis... This paper constructed a carbon emission identity based on five factors: industrial activity, industrial structure, energy inten- sity, energy mix and carbon emission parameter, and analyzed manufacturing carbon emission trends in Jilin Province at subdivided industrial level through Log-Mean Divisia Index (LMDI) method. Results showed that manufacturing carbon emissions of Jilin Province increased 1.304 ~ 107t by 66% between 2004 and 2010. However, 2012 was a remarkable year in which carbon emissions decreased compared with 2011, the first fall since 2004. Industrial activity was the most important factor for the increase of carbon emissions, while energy intensity had the greatest impact on inhibiting carbon emission growth. Despite the impact of industrial structure on carbon emissions fluctuated, its overall trend inhibited carbon emission growth. Further, influences of industrial structure became gradually stronger and surpassed energy intensity in the period 2009-2010. These results conclude that reducing energy intensity is still the main way for carbon emission reduction in Jilin Province, hut industrial structure can not be ignored and it has great potential. Based on the analyses, the way of manufacturing industrial structure adjustment for Jilin Province is put forward. 展开更多
关键词 MANUFACTURING carbon emissions influencing factors Log-Mean Divisia Index (LMDI) industrial structure adjustment Jilin Province China
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