DEVELOPMENT OF THE FUNCTIONS FOR AUTOMATED DENSITY CORRECTION AND MOISTURE GRADIENT MEASUREMENT OF HIGH FREQUENCY MOISTURE METER

研究了高频水分仪密度校正和水分梯度测量功能的开发，提出了一种电极扫描法测量水分梯度。在该方法中，测量了电容随电极距离的变化。由电极扫描引起的电容变化C（d）被定义为以下积分方程C（d）=* S（d，x）U（x）dx，其中S（d，x）是权重函数，U（x）是湿度梯度。为了求解该方程，引入了一个线性方程组。通过实验确定了不同含水率梯度的模型试件的权函数，并对电容曲线与含水率梯度的关系进行了仿真研究。结果表明：（1）在高频水分计中，电容对电极附近的水分状况非常敏感。(2)电容随电极间距的增加呈指数下降。(3)随着极距的增大，深部相对灵敏度增大。(4)水分梯度的反解不稳定，水分梯度的再现性不够。父亲的数学处理应该是必需的。(5)研究结果的实际应用是对电容曲线的频谱模式进行分类。木材密度对高频水分仪的测量有很大的影响。在本研究中，提出了同时测定密度和水分含量，并检查了以下算法。将Kollmann密度-水分含量图与水分计的阅读结果相结合。这些值在两到三次迭代中收敛，并证实了所提出的算法的适当性。

Development of the functions for density correction and moisture gradient measurement of high frequency moisture meter was investigated.In order to evaluate the moisture gradient, an electrode scanning method was proposed. In this method, the capacitance change in function of electrode distance was measured. The capacitance curve pattern showed good correlation with the moisture gradient pattern.The capacitance change due to electrode scanning C (d) was defined as the following integral equation, C (d)=* S (d, x) U (x) dx, where S (d, x) is a weight function and U (x) is a moisture gradient. In order to solve this equation, a linear simultaneous equation was introduced. The weight function was experimentally determined from model specimens with different moisture gradient.Simulation research was made to investigate the relationship between the capacitance curve and the moisture gradient. The following results were obtained : (1) In these high frequency moisture meter, the capancitance is sensitive very much to the moisture condition near electrodes. (2) The capacitance decreases exponentially with increase of the electrode distance. (3) As the electrode distance increases, relative sensibility of deep position increases. (4) The inverse solution of moisture gradient was not stable, and the reproduce of the moisture gradient was insufficient. Father mathematical treatment should be required. (5) Practical application of the results is to classify the spectrum patterns of the capacitance curves.Wood density affects very much on the measurement of a high frequency moisture meters. In this research, a simultaneous determination of a density and moisture content was proposed, and the following algorism was examined. The Kollmann's density-moisture content figure was combined with the result of the reading of a moisture meter. These values converged in two or three times of iteration, and the propriety of the proposed algorism was confirmed.