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对流层臭氧卫星遥感反演综述
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作者 许健 张卓 +13 位作者 饶兰兰 王雅鹏 闫欢欢 胡斯勒图 石崇 刘嵩 格根塔娜 王文煜 石恩涛 姚舜 朱军 王咏梅 董晓龙 施建成 《地球科学进展》 CAS CSCD 北大核心 2024年第1期56-70,共15页
臭氧是地球大气中最重要的痕量气体之一,在气候变化和生态环境中均扮演着至关重要的角色。对流层臭氧作为光化学烟雾的重要成分之一,其浓度变化与人类活动息息相关。基于卫星遥感技术监测对流层臭氧浓度可以帮助我们更好地发现和定量解... 臭氧是地球大气中最重要的痕量气体之一,在气候变化和生态环境中均扮演着至关重要的角色。对流层臭氧作为光化学烟雾的重要成分之一,其浓度变化与人类活动息息相关。基于卫星遥感技术监测对流层臭氧浓度可以帮助我们更好地发现和定量解释对流层臭氧在不同季节、不同时刻以及不同区域的变化特征,探讨臭氧在对流层中的成因机制。随着卫星遥感技术的全面发展,臭氧遥感产品(例如臭氧总量、廓线等)无论在产品精度或是时空分辨率方面均取得了显著进步,然而,由于受较弱卫星信号与复杂下垫面的影响,对流层臭氧遥感产品精度仍无法满足目前对流层大气成分的精细化科学应用研究。主要围绕对流层臭氧卫星遥感,回顾和分析了臭氧卫星遥感载荷的发展历程和现状,结果表明国内外已基于不同谱段(紫外—可见光、热红外和太赫兹)实现了全球及区域臭氧的时空分布探测;讨论了基于不同技术遥感反演算法(直接与间接反演、多波段联合反演、天底—临边协同反演、基于机器学习技术的创新算法等)的特点及适用性,分析表明算法精度的提升包括从复杂大气背景下的辐射传输模拟、基于地面观测的先验信息优化以及仪器定标与信噪比等多方面的工作;展望了卫星遥感在全球和区域尺度提供可靠对流层臭氧观测数据的应用前景,为对流层臭氧污染的形成机理、人类活动与气候变化如何影响对流层臭氧浓度变化等方面的研究提供关键数据支撑。 展开更多
关键词 卫星遥感 对流层臭氧 大气反演
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饱和超固结黏性土的三剪弹塑性本构模型研究 被引量:8
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作者 胡小荣 董肖龙 +1 位作者 胡勃阳 陈晓宇 《固体力学学报》 CSCD 北大核心 2017年第6期579-590,共12页
针对饱和超固结黏性土现有下加载面修正剑桥模型中破坏应力比为定值、土体黏聚力为零,以及不能准确反映不同应力状态下土的强度差异这些问题,基于三剪统一强度准则以及应力坐标平移法得到了扩展破坏应力比,其特点是能更好地反映应力状... 针对饱和超固结黏性土现有下加载面修正剑桥模型中破坏应力比为定值、土体黏聚力为零,以及不能准确反映不同应力状态下土的强度差异这些问题,基于三剪统一强度准则以及应力坐标平移法得到了扩展破坏应力比,其特点是能更好地反映应力状态变化以及土体黏聚力的影响.在此基础上提出了饱和超固结黏性土的三剪弹塑性本构模型,该模型的特点是能描述土体受力时的中间主应力效应,应力区间效应和拉压差影响,同时也能更好地考虑土体黏聚力的影响.基于该模型对ABAQUS软件进行了二次开发,对江西赣南崩岗土常规三轴压缩条件下力学特性作了模拟和试验结果对比,结果表明所提模型能很好地反映土体不同超固结比下的变形、剪胀、孔隙水压力变化特性.并利用其模拟了饱和超固结黏性土在不排水和排水条件下的真三轴和常规三轴压缩试验特性. 展开更多
关键词 饱和超固结黏性土 三剪弹塑性本构模型 三剪统一强度准则 扩展破坏应力比
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The Coix Genome Provides Insights into Panicoideae Evolution and Papery Hull Domestication 被引量:12
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作者 Chao Guo Yanan Wang +22 位作者 Aiguo Yang Jun He Chaowen Xiao Shanhua Lv Fengming Han Yibing Yuan Yuan Yuan xiaolong dong Juan Guo YawenYang-Hailan Liu Ningzhi Zuo Yaxi Hu Kangxu Zhao Zhengbo Jiang Xing Wang Tingting Jiang Yaou Sherf Moju Cao Yuan Wang Zhaobo Long Tingzhao Rong Luqi Huang Shufeng Zhou 《Molecular Plant》 SCIE CAS CSCD 2020年第2期309-320,共12页
Coix is a grass crop domesticated as early as the Neolithic era.It is still widely cultivated for both highly nutritional food and medicinal use.However,the genetic study and breeding of this crop are hindered by the ... Coix is a grass crop domesticated as early as the Neolithic era.It is still widely cultivated for both highly nutritional food and medicinal use.However,the genetic study and breeding of this crop are hindered by the lack of a sequenced genome.Here,we report de novo sequencing and assembly of the 1619-Mb genome of Coix,and annotation of 75.39%repeats and 39629 protein-coding genes.Comparative genomics analysis showed that Coix is more closely related to sorghum than maize,but intriguingly only Coix and maize had a recent genome duplication event,which was not detected in sorghum.We further constructed a genetic map and mapped several important traits,especially the strength of hull.Selection of papery hull(thin:easy dehulling)from the stony hull(thick:difficult dehulling)in wild progenitors was a key step in Coix domestication.The papery hull makes seed easier to process and germinate.Anatomic and global transcriptome analysis revealed that the papery hull is a result of inhibition of cell division and wall biogenesis.We also successfully demonstrated that seed hull pressure resistance is controlled by two major quantitative trait loci(QTLs),which are associated with hull thickness and color,respectively.The two QTLs were further fine mapped within intervals of 250 kb and 146 kb,respectively.These resources provide a platform for evolutionary studies and will facilitate molecular breeding of this important crop. 展开更多
关键词 COIX GENOME Comparative genomics PANICOIDEAE EVOLUTION HULL DOMESTICATION QTL mapping
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Multipoint fiber-optic laser–ultrasound generation along a fiber based on the core-offset splicing of fibers
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作者 xiaolong dong SHIMIN GAO +1 位作者 JIAJUN TIAN YONG YAO 《Photonics Research》 SCIE EI 2017年第4期287-292,共6页
Fiber-optic laser–ultrasound generation is being used in an increasing number of applications, including medical diagnosis, material characterization, and structural health monitoring. However, most currently used fi... Fiber-optic laser–ultrasound generation is being used in an increasing number of applications, including medical diagnosis, material characterization, and structural health monitoring. However, most currently used fiber-optic ultrasonic transducers allow effective ultrasound generation at only a single location, namely, at the fiber tip, although there have been a few limited proposals for achieving multipoint ultrasound generation along the length of a fiber. Here we present a novel fiber-optic ultrasound transducer that uses the core-offset splicing of fibers to effectively generate ultrasound at multiple locations along the fiber. The proposed laser–ultrasonic transducer can produce a balancedstrength signal between ultrasonic generation points by reasonably controlling the offsets of the fibers. The proposed transducer has other outstanding characteristics, including simple fabrication and low cost. 展开更多
关键词 CORE mode EDFA rate Multipoint fiber-optic laser ultrasound generation along a fiber based on the core-offset splicing of fibers
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