木材中的水分对木材的性能有着决定性的影响，目前测量木材水分的方法多适用于小型木材的检测．然而，当树木被砍伐后，在加工前希望了解其内部水分状态，因此需要一种方法来检测大型原木的水分．该文设计了一种微型核磁共振(NMR)传感器，该传感器为圆柱型结构（直径为 28 mm，长度为 60 mm），测量区域位于传感器外侧，形成与传感器同轴的圆环．测量前，需在被测部位凿一个与传感器直径相当的孔．测量时传感器沿着孔壁测量即可获得对应位置的 NMR 参数信息．初步实验结果表明，该传感器可以分辨被测木材中自由水和束缚水的分布以及各部位水分的相对含量．

The content and distribution of water in wood affect its performance. So far, most technologies to measure water content/distribution can only be applied to small wood samples. A method to measure the water content inside large timber is urgently needed, given that information on water content/distribution inside the harvested timber is often required before the timber can be processed to products. In this work, a mini cylindrical NMR sensor (i.e., 28 mm in diameter and 60 mm in length) for measuring water content inside large timber was designed. The sensitive volume is a coaxial ring just outside of the sensor. For measurement, the sensor needs to be placed inside a hole drilled on the timber, which has a similar diameter with the sensor. By moving the sensor around the wall of the hole, the NMR parameters of the timber could be measured. Preliminary experimental results showed that the sensor can detect signals from both free water and the bound water in large timber, and such signals can be used to calculate relative water contents.