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以学科内容“深度系统化”为基础,促进物理观念水平提高
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作者 马永毅 《物理教学》 北大核心 2023年第5期8-13,7,共7页
本文通过对物理课程标准中“物理观念”五个层次学业质量标准水平的分析,梳理出了物理观念水平提高的详细途径。通过分析学科内容“深度系统化”的内涵及表现,提出了依托基本结构系统、有效应用系统、优化提升系统,并设计了“基本结构... 本文通过对物理课程标准中“物理观念”五个层次学业质量标准水平的分析,梳理出了物理观念水平提高的详细途径。通过分析学科内容“深度系统化”的内涵及表现,提出了依托基本结构系统、有效应用系统、优化提升系统,并设计了“基本结构系统”形成流程,和“有效应用系统”形成流程,提出从知识点主线、模型主线、方法主线、主题主线等多角度的去建立动态优化提升系统的设想。 展开更多
关键词 物理观念水平 深度系统化 基本结构 综合应用 关键概念
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Root Structure,Distribution and Biomass in Five Multipurpose Tree Species of Western Himalayas 被引量:1
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作者 Kartar Singh VERMA Sandeep KOHLI +1 位作者 Rajesh KAUSHAL Om Parkash CHATURVEDI 《Journal of Mountain Science》 SCIE CSCD 2014年第2期519-525,共7页
【Title】【Author】【Addresses】1The tree root distribution pattern and biomass of seventeen year old trees of Grewia optiva, Morus alba, Celtis australis, Bauhinia variegata and Robinia pseudoacacia were studied by e... 【Title】【Author】【Addresses】1The tree root distribution pattern and biomass of seventeen year old trees of Grewia optiva, Morus alba, Celtis australis, Bauhinia variegata and Robinia pseudoacacia were studied by excavation method. B. variegata roots penetrated to a maximum depth of 4.78 m, whereas, M. alba roots were found down to 1.48 m depth. Lateral spread was minimum in B. variegata (1.10 m)and maximum inR. pseudoacacia (7.33 m). Maximum root biomass of 6.30 kg was found in R. pseudoacacia and minimum (2.43 kg) was found in M. alba. For four species viz.,G. optiva, M. alba, C. australis andR. pseudoacacia, 68%-87% root biomass occurred within top 0-30 cm soil depth, but forB. variegata this was only45%. The soil binding factor was maximum in G. optiva and minimum in B. variegata. Soil physico-chemical properties also showed wide variation. The study suggests thatB. variegata with a deep root system is the most suitable species for plantation under agroforestry systems. R. pseudoacacia and G. optiva with deep root systems, more lateral spread and high soil binding factor are suitable for plantation on degraded lands for soil conservation. 展开更多
关键词 Root categories Root distribution Root biomass Soil binding factor Soil conservation NUTRIENTS
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