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Relationship between acoustic emission characteristics generated with water conductivity of xylem and wood anatomy

木质部水电导率产生的声发射特性与木材解剖结构的关系

基本信息

批准号：
13660158
负责人：
SATO Keiichi
金额：
$ 0.32万
依托单位：
Tokyo University of Agriculture and Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

项目摘要

The acoustic emission from seedlings and adult trees was detected to relate to the transpiration or anatomical structure of vessels. There was significant relationship between AE events and amount of transpiration that is water flow through the vessels. Small specimens were cut from xylem of adult trees, and used for the water conductivity testing. Results were discussed hydrodynamically. The flow rate was determined by the pressure difference, the diameter of a vessel and number of vessel based on the Hagen-Poiseuille's law. There was relationship between AE events and the number of vessel. The AE generation was observed proportionally to the flow rate when the water flow velocity was over a certain value.The AE generation from seedlings and trees was depended on the climate and the water condition of the plants. It is possible to apply the AE technique to detection of the water stress of plants and to tree diagnosis. The AE generation occurred by not only the transpiration but also the shoot glowing, then the technique would be able to use for the research of tree phenologyIt is necessary to study ultrasonic properties propagating in the wood for the application of the ultrasonic to the tree diagnosis such as the AE and ultrasonic CT. The scanning acoustic microscope (SAM) was used for the measurement of isotropic wave velocity on the cell wall of tracheids. The wave velocity depended on the micro-fibril angle. The transverse wave velocity measured with a pulsar-and-receiver of the acousto-ultrasonic was depended on the anatomic wood structure.

从幼苗和成年树木的声发射检测到的蒸腾或解剖结构的导管。有显着的AE事件之间的关系和蒸腾量，即水流量通过导管。从成年树木的木质部切下小样本，并用于水传导性测试。结果进行了讨论流体动力学。根据哈根-普瓦勒定律，通过压差、血管直径和血管数量确定流速。不良事件发生率与血管数目有关。当水流速度超过一定值时，声发射的产生与水流速度成正比，幼苗和树木的声发射受气候和植物水分条件的影响。声发射技术有可能应用于植物水分胁迫的检测和树木诊断。声发射的产生不仅是由于蒸腾作用，而且也是由于枝条发光作用，因此，该技术可用于树木物候学的研究。研究超声波在木材中的传播特性，对于将超声波应用于树木的诊断，如声发射和超声CT是必要的。利用扫描声学显微镜（SAM）对管胞细胞壁各向同性波速进行了测量。波速取决于微纤丝角。用超声脉冲接收器测量木材的横波速度取决于木材的解剖结构。