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基于超声断层成像的小动物器官声速成像 被引量:1
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作者 胡智明 杨明春 +1 位作者 朱翔 田超 《中国科学技术大学学报》 CAS CSCD 北大核心 2022年第1期61-66,F0003,共7页
声速是表征组织的一个重要声学参数。我们开发了一种超声断层成像(USCT)系统,用于小动物器官的体外声速成像和评估。该USCT系统采用256个阵元的环形阵列换能器,并允许所有通道同时进行信号传输和接收。该方法不需要复杂的样品制备程序,... 声速是表征组织的一个重要声学参数。我们开发了一种超声断层成像(USCT)系统,用于小动物器官的体外声速成像和评估。该USCT系统采用256个阵元的环形阵列换能器,并允许所有通道同时进行信号传输和接收。该方法不需要复杂的样品制备程序,测量结果准确。实验结果表明,该方法测量的离体大鼠脑、心、肝、脾、肾的声速与已发表的数据接近。这项工作展示了一种新的声速成像方法,并具有在体应用潜力。 展开更多
关键词 超声断层成像 声速度 组织表征 图像重建
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Impact of soil compaction on the rill erosion of Mollisol by waterflow:A comparative analysis before and after the seasonal freezing and thawing
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作者 Boxiang Zhang Yanfeng Jia +8 位作者 Haoming Fan Chengjiu Guo Fangli Su Shuang Li Juan Fu Xi Zhang Mingyao Yu mingchun yang Renming Ma 《International Soil and Water Conservation Research》 2025年第4期756-770,共15页
Soil erosion resulting from soil compaction and freeze-thaw action is a major global environmental issue in intensively mechanized agricultural and cold regions.Existing studies predominantly focus on the direct effec... Soil erosion resulting from soil compaction and freeze-thaw action is a major global environmental issue in intensively mechanized agricultural and cold regions.Existing studies predominantly focus on the direct effects of freeze-thaw cycles on soil erosion,yet overlook the legacy effects of pre-freeze-thaw soil compaction.This study aimed to reveal the cross-temporal impact mechanisms of pre-freeze-thaw soil compaction on post-freeze-thaw soil erosion and how soil properties drive these effects.A comparative study was conducted in the Mollisol region of Northeast China by utilizing in situ field erosion experiments and soil property measurements under various compaction levels before and after the freeze-thaw period.Results showed that before the freeze-thaw period,compaction significantly increased total runoff and sediment mass(p<0.05).After the freeze-thaw period,the sediment mass of compacted soil decreased by 1.84%-57.73%compared to before the freeze-thaw period,but still increased by 28.59%-148.22%compared to uncompacted soil.The structural equation model revealed that before the freeze-thaw period,the influence of soil properties on runoff was greater than their direct effect on sediment mass,and the sediment mass variation was mainly driven by runoff scouring due to soil compaction.After the freeze-thaw period,the decreased soil erosion resistance(aggregate stability and soil strength)and the increased runoff caused by the legacy effects of compaction were the primary reasons for higher sediment mass in compacted soil compared to uncompacted soil.This study highlights the crucial role of human activities before the freeze-thaw period in influencing subsequent erosion dynamics,providing essential insights for erosion control and soil restoration in vulnerable farmlands. 展开更多
关键词 Soil compaction Freeze and thaw cycles RUNOFF Soil erosion Chinese Mollisol
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