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扫描仪分辨力和动态密度范围的评价方法
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作者 任云 《印刷杂志》 2003年第12期48-51,共4页
关键词 扫描仪 分辨力 动态密度范围 评价方法 性能指标
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谈滚筒扫描仪与平面扫描仪——PMT与CCD的比较
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作者 彭勃 《印刷世界》 1995年第4期7-9,共3页
滚筒扫描仪和平面扫描仪是摄取图象、文字、信息的重要工具,在图像、文字信息处理,特别是制版印刷领域有广泛的应用.一般经验认为,滚筒扫描仪比平面扫描仪在质量和效率方面占有较大优势,历史发展的轨迹也显示了这种事实,滚筒扫描仪与记... 滚筒扫描仪和平面扫描仪是摄取图象、文字、信息的重要工具,在图像、文字信息处理,特别是制版印刷领域有广泛的应用.一般经验认为,滚筒扫描仪比平面扫描仪在质量和效率方面占有较大优势,历史发展的轨迹也显示了这种事实,滚筒扫描仪与记录仪一体。 展开更多
关键词 平面扫描 滚筒扫描 扫描分辨率 扫描仪 CCDS 质量因素 输出分辨率 CCD元件 动态密度范围 最小密度
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Composition,Structure and Regeneration Dynamics of Olea ferruginea Royle Forests from Hindukush Range of Pakistan
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作者 NASRULLAH Khan FAYAZ Ali +1 位作者 KISHWAR Ali SHAHID Shaukat 《Journal of Mountain Science》 SCIE CSCD 2015年第3期647-658,共12页
Abstract" The abundance of Olea ferruginea in Malakand Division has been significantly reduced across its distribution range due to anthropogenic pressure in the recent past. A number of initiatives were taken for gr... Abstract" The abundance of Olea ferruginea in Malakand Division has been significantly reduced across its distribution range due to anthropogenic pressure in the recent past. A number of initiatives were taken for grafting this species to obtain better seeds for oil production, without the basic information on their ecology and management. To address this knowledge gap, we quantified the composition, structure and regeneration dynamics of Olea ferruginea forests in Malakand Division, Hindukush range of Pakistan. In the present study, five communities dominated by Oleaferruginea were identified using Ward's agglomerative cluster analysis. Total tree density ranged from 153-26o2 plants/ha, and basal area from 19.55 to 2353 m~ ha-1 with Olea having a relative density of 51% to 87% and basal area of 48% to 93%, respectively. The density of juveniles of the dominant and subordinate tree species were generally low which reflect their narrow distribution in the study area. Size-class distributions of O. ferruginea disclosed a bell-shaped pattern, indicating that forests were heavily exploited by local inhabitants in previous periods and recently by armed forces owing to security risks in the study area. The age (mean max. 300±34 years) and annual increment (3.2±1.2 years/cm) indicates that the species is long lived and generally slow growing among the different broad leaved species studied so far. However, the oldest trees can be found by the exploration of large diameter trees in the area. In addition, we found a stable linear relationship between the age and diameter (r2 = o.779), indicating that diameter is a good predictor of age for this broad leaved species. In view of its relatively slow growth, longevity and positive ring-width characteristics O. ferruginea seems to be a suitable choice for dendroecological and dendrochronological studies in lesser Himalayan and Hindukush ranges of Pakistan. The results obtained from this study may help in understanding the composition, structure and regeneration dynamics of other subtropical broad leaved species. 展开更多
关键词 Oleaferruginea Species composition Ward's agglomerative cluster analysis SEEDLING DENDROECOLOGY
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