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A Study of Linke Turbidity Factor over Qena / Egypt
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作者 Sayed M. Elshazly 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 1996年第4期519-532,共14页
Data on instantaneous atmospheric Linke turbidity factor TL (m) are reported for clear days at Qena/Egypt in the period from June 1992 to May 1993.TL(m) is determined using the values of irradiance of direct solar rad... Data on instantaneous atmospheric Linke turbidity factor TL (m) are reported for clear days at Qena/Egypt in the period from June 1992 to May 1993.TL(m) is determined using the values of irradiance of direct solar radiation (I),which are calculated from global (G) and diffuse (D) - solar radiation measurements.Monthly and seasonally variations of both diurnal and daily average values of TL (m) increases steadily in the direction of sunset in the months from June to December 1992 as well as Summer and Autumn seasons,while it falls generally in this direction for the months from January to March and Winter season.In April and May,TL (m) fluctuates obviously through the day hours,it is also shown that the average values of TL(m) are particularly large during Summer months compared to other months of the year.This behavior of TL(m) is discussed in view of the variations of some weather elements,which affect the content of water vapor and dust particle in the atmosphere of the study region.It seems t be of similar trends to that of other locations inside and outside Egypt.The virtual variation of TL(m) is eliminated by reducing its value to relative optical air mass m=2,according to Kasten formula.The resulting TL (2) is more representative for the content of dust particles and water vapor in the atmosphere. 展开更多
关键词 TURBIDITY linke turbidity factor Seasonal and diurnal variations Solar radiations components measurements AEROSOL
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一种考虑尺寸效应的缺口件疲劳寿命预测方法 被引量:7
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作者 奚蔚 姚卫星 《南京航空航天大学学报》 EI CAS CSCD 北大核心 2013年第4期497-502,共6页
提出了一种考虑尺寸效应的缺口件疲劳寿命预测方法。该方法首先将缺口件等效成一个参考光滑件,参考光滑件与缺口件外加应力的比值由缺口件疲劳缺口系数决定,参考光滑件尺寸按裂纹可能萌生区域面积相等的原则确定。再基于最弱环节理论,... 提出了一种考虑尺寸效应的缺口件疲劳寿命预测方法。该方法首先将缺口件等效成一个参考光滑件,参考光滑件与缺口件外加应力的比值由缺口件疲劳缺口系数决定,参考光滑件尺寸按裂纹可能萌生区域面积相等的原则确定。再基于最弱环节理论,将参考光滑件等效成一个与已具有试验数据的光滑件(称为标准光滑件)尺寸相同的新光滑件,它们外加应力的比例由Weibull指数和尺寸比例确定。在两次等效的基础上,最终建立缺口件与标准光滑件之间的联系,并提出等效应力的概念,用它查取标准光滑件的疲劳寿命试验数据可直接得到缺口件的疲劳寿命。该方法可考虑到缺口件疲劳损伤场大小对疲劳寿命的影响,并可消除用相同疲劳损伤量查取不同尺寸光滑件的试验数据寿命预测结果不同的现象。进行了材料LY12CZ的带中心孔缺口件的寿命算例分析,预测结果和试验结果吻合良好,表明该方法是有效的。 展开更多
关键词 缺口件 疲劳寿命 最弱环节理论 等效应力 疲劳缺口系数 尺寸效应
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Analysis of Atmospheric Turbidity in Clear Skies at Wuhan,Central China 被引量:2
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作者 Lunche Wang Yisen Chen +2 位作者 Ying Niu German Ariel Salaza Wei Gong 《Journal of Earth Science》 SCIE CAS CSCD 2017年第4期729-738,共10页
The Angstr6m turbidity coefficient (β) and Linke turbidity factor (TL) are used to study the atmospheric conditions in Wuhan, Central China, using measureβd direct solar radiation during 2010-2011 in this study.... The Angstr6m turbidity coefficient (β) and Linke turbidity factor (TL) are used to study the atmospheric conditions in Wuhan, Central China, using measureβd direct solar radiation during 2010-2011 in this study. The results show that annual mean β values generally increase from 0.28 in the morning to 0.35 at noon, and then decrease to 0.1 in the late afternoon during the day; annual mean TL generally varies from 3 to 7 in Central China. Both turbidity coefficients have maximum values in spring and summer, while minimum values are observed in winter months. It also reveals that β values show preponderance (52.8%) between 0.15 and 0.35, 78.1% of TL values are between 3.3 and 7.7, which can be compared with other sites around the world. Relationship between turbidity coefficients and main me- teorological parameters (humidity, temperature and wind direction) have been further investigated, it is discovered that the local aerosol concentrations, dust events in northern China and Southwest Monsoon from the Indian Ocean influences the β values in the study area. 展开更多
关键词 direct solar radiation AngstrOm turbidity coefficient linke turbidity factor Central China.
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Latent Co-interests' Relationship Prediction
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作者 Feng Tan Li Li +1 位作者 Zheyu Zhang Yunlong Guo 《Tsinghua Science and Technology》 SCIE EI CAS 2013年第4期379-386,共8页
With the development of the social media and Internet, discovering latent information from massive information is becoming particularly relevant to improving user experience. Research efforts based on preferences and ... With the development of the social media and Internet, discovering latent information from massive information is becoming particularly relevant to improving user experience. Research efforts based on preferences and relationships between users have attracted more and more attention. Predictive problems, such as inferring friend relationship and co-author relationship between users have been explored. However, many such methods are based on analyzing either node features or the network structures separately, few have tried to tackle both of them at the same time. In this paper, in order to discover latent co-interests' relationship, we not only consider users' attributes but network information as well. In addition, we propose an Interest-based Factor Graph Model (I-FGM) to incorporate these factors. Experiments on two data sets (bookmarking and music network) demonstrate that this predictive method can achieve better results than the other three methods (ANN, NB, and SVM). 展开更多
关键词 linking prediction node similarity social network factor graph model
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