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Detail description of Lithophyllum okamurae(Lithophylloideae,Corallinales), a widely distributed crustose coralline alga in marine ecosystems
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作者 Qunju Hu Fangfang Yang +4 位作者 Zhangliang Wei Jiahao Mo Chao Long xinpeng tian Lijuan Long 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2020年第6期96-106,共11页
Lithophyllum okamurae is one of the important encrusting coralline algae,which plays important roles as primary producer,carbonate sediment builder,and habitat provider in the marine ecosystems.In this study,L.okamura... Lithophyllum okamurae is one of the important encrusting coralline algae,which plays important roles as primary producer,carbonate sediment builder,and habitat provider in the marine ecosystems.In this study,L.okamurae was collected from tropical coast of Sanya,and firstly described based on both detailed morph-anatomical characteristics and molecular studies of typic DNA sequences.The structure of the thalli of L.okamurae was pseudoparenchymatous construction with radially organized dimerous organizations in the crustose portion.The pseudoparenchymatous construction were composed of three parts,including 1 to 3 layers of epithelia cells which had flatten to round outermost walls,one layer of square or rectangular cells of the hypothallia and multiple layers of square or elongated rectangular peripheral cells.Palisade cells were observed,and the cells of the contiguous vegetative filaments were connected by secondary pit-connections with cell fusions absent.The carposporangial conceptacles,the spermatangial conceptacles,the bisporangial conceptacles and the tetrasporangial conceptacles were observed,and all these four kinds of conceptacles were uniporate.The spermatangial conceptacles were slightly convex and buried at shallow depths in the thalli tissues,and the carposporangial conceptacles and asexual conceptacles were protruding and conical.Phylogenetic studies based on DNA barcoding markers of 18 S rDNA,COI,rbc L and psb A revealed that L.okamurae clustered with the closest relation of L.atlanticum,and formed a distinct branch.Based on the comparative anatomical features and the molecular data,the detailed description of the valid species of L.okamurae was firstly given in this study to provide theoretical basis for algae resources utilization and conservation in marine ecosystems. 展开更多
关键词 Lithophyllum okamurae crustose coralline algae marine ecosystem morphological characteristics conceptacles DNA-barcoding
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基于多尺度模型解释固体中的挠曲电效应
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作者 马润玉 郝一涵 +1 位作者 田新鹏 邓谦 《固体力学学报》 CAS CSCD 北大核心 2022年第4期477-484,共8页
挠曲电效应是一种跨尺度的多场耦合现象.当前的宏观挠曲电理论均是基于应变梯度局部破坏晶体反演对称这一微观机理对该现象进行唯象描述.该宏观理论与基于晶格动力学及密度泛函理论的微观挠曲电理论模型之间存在较大差异.难以将两者结... 挠曲电效应是一种跨尺度的多场耦合现象.当前的宏观挠曲电理论均是基于应变梯度局部破坏晶体反演对称这一微观机理对该现象进行唯象描述.该宏观理论与基于晶格动力学及密度泛函理论的微观挠曲电理论模型之间存在较大差异.难以将两者结合用以跨尺度地研究材料中的挠曲电效应.针对该现状,论文基于前人提出的原子场理论,建立了一种新的多尺度挠曲电模型.并在该多尺度模型框架下解释了应变梯度诱发极化的微观机理.一方面,与基于连续介质力学的唯象理论不同,论文从材料微结构演化的角度推导了原子位移与极化的关系.另一方面,与通过晶格波假设原子位移的微观理论不同,论文得到的极化表达式更加真实和广义地解释了挠曲电效应.其能够适用于材料边界存在机械力作用,材料内部存在缺陷等复杂的情况.本文所建立的多尺度挠曲电模型能够为后续多尺度挠曲电效应的研究提供一些思路. 展开更多
关键词 挠曲电效应 连续介质力学 微结构演化 多尺度模型
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