期刊文献+
共找到3篇文章
< 1 >
每页显示 20 50 100
薄壳山核桃果材兼用林建立技术 被引量:3
1
作者 张计育 张凡 +1 位作者 王刚 李永荣 《现代农业科技》 2020年第9期70-70,共1页
薄壳山核桃是集高档干果、木本油料、园林绿化、高档木材于一体的生态经济型树种,果材兼用林的建立有利于充分挖掘利用薄壳山核桃的价值。本文对薄壳山核桃果材兼用林建立技术进行了总结,以期为生产提供指导。
关键词 薄壳山核桃 果材兼用 建林技术
下载PDF
Estimation of the Maximum Annual Loads Modeling for Kingdom of Bahrain 被引量:2
2
作者 Isa Salman Qamber 《Journal of Energy and Power Engineering》 2013年第10期2006-2011,共6页
The present paper proposes the impact of the air temperature on electricity demand as expected. It is clear that the annual maximum load is recorded versus the years starting by the year 2009 up to 2012. At present, t... The present paper proposes the impact of the air temperature on electricity demand as expected. It is clear that the annual maximum load is recorded versus the years starting by the year 2009 up to 2012. At present, the graph fitting technique is applied with some mathematical and computational tools based on the actual values of the years 2009 up to 2012 considering the lower values, the higher values and the average values of the annual maximum loads for Kingdom of Bahrain. For the three scenarios, the models are obtained by curve fitting technique. As well, the model of actual loads is obtained finally which has mostly the closest values obtained. 展开更多
关键词 Annual maximum load curve fitting load scenarios.
下载PDF
Changes in land use/cover mapped over 80 years in the Highlands of Northern Ethiopia 被引量:6
3
作者 ETEFA Guyassa Amaury FRANKL +5 位作者 Sil LANCKRIET BIADGILGN Demissie GEBREYOHANNES Zenebe AMANUEL Zenebe Jean POESEN Jan NYSSEN 《Journal of Geographical Sciences》 SCIE CSCD 2018年第10期1538-1559,共22页
Despite many studies on land degradation in the Highlands of Northern Ethiopia, quantitative information regarding long-term changes in land use/cover(LUC) is rare. Hence, this study aims to investigate the LUC change... Despite many studies on land degradation in the Highlands of Northern Ethiopia, quantitative information regarding long-term changes in land use/cover(LUC) is rare. Hence, this study aims to investigate the LUC changes in the Geba catchment(5142 km2), Northern Ethiopia, over 80 years(1935–2014). Aerial photographs(APs) of the 1930 s and Google Earth(GE) images(2014) were used. The point-count technique was utilized by overlaying a grid on APs and GE images. The occurrence of cropland, forest, grassland, shrubland, bare land, built-up areas and water body was counted to compute their fractions. A multivariate adaptive regression spline was applied to identify the explanatory factors of LUC and to create fractional maps of LUC. The results indicate significant changes of most types, except for forest and cropland. In the 1930 s, shrubland(48%) was dominant, followed by cropland(39%). The fraction of cropland in 2014(42%) remained approximately the same as in the 1930 s, while shrubland significantly dropped to 37%. Forests shrank further from a meagre 6.3% in the 1930 s to 2.3% in 2014. High overall accuracies(93% and 83%) and strong Kappa coefficients(89% and 72%) for point counts and fractional maps respectively indicate the validity of the techniques used for LUC mapping. 展开更多
关键词 fractional map Google Earth land use/cover multivariate adaptive regression Italian aerial photographs
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部