拆样法纤维含量试验结果差异分析

为了分析用拆样法进行纤维含量试验中“湿试样”的湿重含量与“干试样”的净干质量结合公定回潮率含量的结果差异对检测结果的影响，选取1000个试样分别用拆样法进行纤维含量试验，并对试验结果的差异进行了分析。试验结果表明，当试样中纤维的公定回潮率差值≤5％时，湿重含量与净干质量结合公定回潮率含量的差异可以忽略不计；当公定回潮率差值在59／5～10％时，仅有2．1％的湿重含量与净干质量结合公定回潮率含量结果的差异超过1．0％；当公定回潮率差值〉10％时，有9．0％的湿重含量与净干质量结合公定回潮率含量结果的差异超过1．0％。该试验的结论为，在标准大气试验室进行拆样法纤维含量检测时，湿重含量与净干质量结合公定回潮率含量的差值均≤1．0%。

双组分纤维含量拆样法试验结果差异分析

为了提高双组分样品纤维含量拆样法的检测效率，缩短试验周期，统计并分析了用拆样法测试双组分纤维含量试验中湿重含量与净干质量结合公定回潮率含量的结果差异。分析结果表明，测试聚酯／纤维素纤维双组分样品时的湿重含量与净干质量结合公定回潮率含量间的差值超过1．O％的概率为20．3％，而绝大部分纤维素纤维／氨纶、锦纶／纤维素纤维和羊毛／桑蚕丝的双组分样品的湿重含量与净干质量结合公定回潮率含量问的差值小于0．5％，全部样品的湿重含量与净干质量结合公定回潮率含量间的差值小于1．0％，完全可以满足日常检测和抽查需求。所以，在用拆样法测试聚酯／纤维素纤维双组分样品的纤维含量时必须采用净干质量结合公定回潮率的含量；在用拆样法测试纤维素纤维／氨纶、锦纶／纤维素纤维和羊毛／桑蚕丝的双组分样品时可以直接采用湿重含量。

Effects of Grain Angle on Reproducibility and Accurate Measurement of Moisture Content of Wood Samples Using a Pin-Style Moisture Meter

Studies were conducted on the effects of grain angle on reproducibility and accurate measurement of moisture content of four wood samples using a pin-style moisture meter. The wood samples were partitioned into four quadrants and moisture contents were measured along the grain direction in the first and second quadrants from 0 degree to 150 degrees insteps of 30 degrees. Experimental results indicated that the average moisture content remained constant as the grain angle increased. Repeated measurements of moisture content at different grain angles or points on the wood surface showed similar patterns of variation. Within-point standard deviations of the moisture contents were greater than between-point standard deviations. A non-destructive method of measuring moisture content at the same location or point on the wood surfaces could not be proposed because of the high variation of moisture content when repeated measurements were taken at the same point. Instead, accurate measurements of moisture content could be obtained at random positions within a radius of 30 mm from the point of intersection of the moisture content axis and the grain angle.