Comparison of Four Kinds of Measurement Techniques for Wood Microfibril Angle
HUANG Yan-hui1, FEI Ben-hua1*,ZHAO Rong-jun2
1. Beijing Forestry Machine Institute, State Forestry Administration, P. R. China, Beijing 100029, China 2. Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, China
Abstract：X-ray diffraction technique, pit aperture observing technique, polarized light microscope technique and near infrared spectrum technique were used separately to test the wood microfibril angle of Chinese fir, and the results were as follows: For the identical tree of Chinese fir, the average microfibril angle obtained by the polarized light microscope technique was the biggest, followed by those obtained by X-ray diffraction technique, and then by polarized light microscope technique, but the difference in the average microfibril angle was not significant. For the different annual rings, the microfibril angle obtained by X-ray diffraction technique became the biggest after the 20th annual ring, the fluctuation of the microfibril angle got by the pit aperture observing technique were big, but the fluctuation got by the polarized light microscope technique was just the reverse. The measurement value curves got by the three techniques were fitted well, and the difference in the average microfibril angle was not significant between different annual rings. For the microfibril angle of the same annual ring, the difference between the maximum and the minimum value tested by the polarized light microscope technique was less than 4°, but the difference tested by the pit aperture observing technique achieved 21.53°, and the standard deviation achieved 4.75. The near infrared spectrum and the X-ray diffraction techniques were all called nondestructive testing techniques. The model set up by the two techniques was very good because of its high prediction and repeatability, and the model was also good for online analysis. The R2 of calibration model and tested model achieved 0.81 and 0.75 respectively，and the standard error of calibration and prediction were 1.79 and 2.02 respectively. In addition, the near infrared spectrum technique could be also used with the other three techniques to predict the wood microfibril angle，showing the superiority of the near infrared spectrum technique. Meanwhile, the advantages and shortcomings were analyzed for the four kinds of measurement techniques.
[1] LI Jian, LIU Yi-xing, CUI Yong-zhi, et al(李 坚，刘一星，崔永志, 等). J. Northeast Forestry University(东北林业大学学报)，1999，27(4)：23. [2] Cockrell F A. Journal of Forestry, 1946, 44: 876. [3] YANG Wen-zhong, FANG Sheng-zuo(杨文忠，方升佐). J. Northeast Forestry University(东北林业大学学报)，2004，32(1)：25. [4] Yang J L, Evans R. Holz, Als Roh-und Werkstoff, 2003, 61: 449. [5] Evans R, Ilic J. For. Prod. J., 2001, 51(3): 53. [6] Hunt D G, Gril J. Estimation of Wood Cell Wall Compliances from Creep Measurements. in: Butterfield B G (Ed.), Microfibril Angle in Wood, the Proceeding of the IAWA/IUFRO International Workshop on the Significance of Microfibril Angle to Wood Quality. Christchurch, New Zealand: University of Canterbury Press, 1997: 397. [7] HUANG Yan-hui, ZHAO Rong-jun, FEI Ben-hua, et al(黄艳辉，赵荣军，费本华, 等). J. Northwest Forestry College(西北林学院学报)，2006，21(4)：184. [8] YI Si-ci, RUAN Xi-gen, SUN Cheng-zhi, et al(尹思慈，阮锡根，孙成志, 等). Scientia Silvae Sinicae(林业科学)，1986，22(2)：209. [9] RUAN Xi-gen, YI Si-ci, SUN Cheng-zhi(阮锡根，尹思慈，孙成志). Scientia Silvae Sinicae(林业科学)，1982，18(1): 64. [10] JIANG Ze-hui, HUANG An-min, FEI Ben-hua, et al(江泽慧，黄安民，费本华, 等). Spectroscopy and Spectral Analysis(光谱学与光谱分析)，2006，26(7)：1230. [11] Huang C L, Kutscha N P, Leaf G J, et al. Comparison of Microfibril Angle Measurement Techniques. in: But Terfield B G (Ed.), Microfibril Angle in Wood, the Proceeding of the IAWA/IUFRO International Workshop on the Significance of Microfibril angle to Wood Quality. Christchurch, New Zealand: University of Canterbury Press, 1997. 177. [12] Saranpaan P, Serimaa R, Andersson S, et al. Variation of Microfibril Angle of Norway Spruce and Scots Pine-Comparing X-ray Diffraction and Optical Methods. in: But terfield B G (Ed.), Microfibril Angle in Wood, the Proceeding of the IAWA/IUFRO International Workshop on the Significance of Microfibril Angle to Wood Quality. Christchurch, New Zealand: University of Canterbury Press, 1997. 240. [13] Andersson S, Serimma R, Torkkeli M, et al. The Japan Wood Research Society, 2000, 46: 343. [14] Peura M, Muller M, Serimaa R, et al. Nuclear Instruments and Methods in Physics Research, 2005, B238: 16. [15] JIANG Ze-hui, HUANG An-min(江泽慧，黄安民). Spectroscopy and Spectral Analysis(光谱学与光谱分析)，2006，26(8)：1464.
