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Estimating the costs of one hectare of poplar planting and supplying wood required for producing various types of paper in Iran
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作者 Majid AZIZI 《Forestry Studies in China》 CAS 2013年第4期349-356,共8页
In Iran, due to abundant restrictions on harvesting wood from northern forests by implementing the preservation project and also lack of possibility for sufficient wood production, development of the area of planting ... In Iran, due to abundant restrictions on harvesting wood from northern forests by implementing the preservation project and also lack of possibility for sufficient wood production, development of the area of planting poplar is quite inevitable. Poplar wood properties have special importance to produce many wood production, particularly pulp and paper. Paper factories are the major consumers of poplar wood at the global level and this is because of unique morphological, physical, mechanical and technological properties of poplar wood. Therefore, regarding the importance of using this species in making various printing and writing paper, packaging or carton, cardboard and newsprint, in this study, costs of poplar production in one hectare including planting and harvesting were examined and determined. Then, based on conversion coefficients of FAO, required round wood, productivity and the cost of poplar wood were calculated for the producing various kinds of paper. The results indicate that carton and cardboard paper or packaging allocate the lowest cost and highest return, while printing and writing paper had highest cost and lowest return in terms of poplar wood supply needed for paper production. 展开更多
关键词 poplar packaging paper newsprint paper printing and writing paper PLANTING conversion coefficient productivity
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毛白杨落叶的分解及叶上小型真菌种群的演替 被引量:12
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作者 李越中 郑是琳 姜广正 《微生物学报》 CAS CSCD 北大核心 1992年第4期299-304,共6页
毛白杨(Populus tomentosa Carr.)在我国以黄河中、下游为分布中心。它作为绿化树种而广为种植。其落叶主要在地表层的土壤(5—15cm)中分解。各种不同的土壤微生物参与落叶的实质性分解,其中真菌起主要作用。落叶分解的研究在国内报道... 毛白杨(Populus tomentosa Carr.)在我国以黄河中、下游为分布中心。它作为绿化树种而广为种植。其落叶主要在地表层的土壤(5—15cm)中分解。各种不同的土壤微生物参与落叶的实质性分解,其中真菌起主要作用。落叶分解的研究在国内报道较少。落叶分解过程中叶上小型真菌种群的研究,国内尚无完整的工作。本文报道了毛白杨落叶在一年内的分解和叶上小型真菌种群的演替,并探讨了温度和湿度对分解的影响。 展开更多
关键词 毛白杨 真菌种群 演替
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《白杨礼赞》与中国现代抒情散文的转折 被引量:2
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作者 吕东亮 《延安大学学报(社会科学版)》 2007年第1期36-40,共5页
茅盾的经典散文《白杨礼赞》呈现了新的写作姿态,进而标识了中国现代抒情散文的转折。它的诞生与茅盾的西北旅行和西北发现紧密相关。《白杨礼赞》所呈现出的新的意象和新的情感是20世纪40年代文学的重要表征之一。《白杨礼赞》开启了... 茅盾的经典散文《白杨礼赞》呈现了新的写作姿态,进而标识了中国现代抒情散文的转折。它的诞生与茅盾的西北旅行和西北发现紧密相关。《白杨礼赞》所呈现出的新的意象和新的情感是20世纪40年代文学的重要表征之一。《白杨礼赞》开启了新的写作范式,同时也影响了现代抒情散文文脉的流延。 展开更多
关键词 《白杨礼赞》 写作姿态 转折 文脉
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