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测量不确定度是测量技术的重要概念,只要涉及到测量数据的场合,都不可避免地牵涉到测量不确定度。本文介绍了人造板静曲强度的测量不确定度评定的方法,并对实验室自制定向刨花板静曲强度进行测量不确定度的评定,得到实验室自制定向刨花板静曲强度为：σb=（60±3）MPa,其中扩展不确定度的包含因子kp=1.985,置信概率p=95%。 相似文献
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选用3种自制阻燃剂浸渍思茅松单板,通过测试胶合板的胶合强度、氧指数和烟密度,分析阻燃剂对胶合板的胶合强度和燃烧性能的影响.研究结果表明:工业制备阻燃胶合板的胶合强度、氧指数、烟密度等级满足国家标准GB/T 17657和GB 8624-2006的要求,说明工业生产阻燃胶合板是可行的.与对照试件相比较,阻燃胶合板的氧指数提高了75.8％～149.8％、烟密度等级降低了15.4％～60.5％、胶合强度降低了43.9％ ～ 56.1％;其中阻燃剂FR-B对胶合板氧指数影响最大,阻燃剂FR-A对胶合板的烟密度影响最大,阻燃剂FR-C对胶合板的胶合强度影响最小. 相似文献
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涂胶量对胶合强度的影响 总被引：1，自引：0，他引：1
本文通过实验数据的整理,绘制出在一定工艺条件下桦木、柳桉、山樟三个树种胶合板的涂胶量与胶合强度的关系曲线,由此提出临界涂胶量的概念。同时对涂胶量、热压压力和胶合强度、木材压缩率进行研究,提出在胶合板生产中确定合理涂胶量值的方法,以保证在取得合格的胶合强度的同时,达到降低成本的目的。并对临界涂胶量值进行了理论分析。 相似文献
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在单板表面喷雾施涂异氰酸酯胶黏剂,热压制备无醛胶合板,比较不同树种的单板材料无醛胶合板的胶合性能,比较施胶后陈放时间对胶合性能的影响。结果表明,单板的材种对无醛胶合板性能有影响,杨木、桦木、尾叶桉这三种阔叶材的无醛胶合板的胶合强度达到了GB/T17657-1999中规定的Ⅰ类胶合板的胶合强度水平,而落叶松和杉木的胶合强度低于这个水平;施胶量为20g/m~2时,放置时间对胶合性能基本没有明显影响。根据试验结果并结合生产实际的成本分析表明,达到Ⅰ类胶合板水平的无醛胶合板的成本较PF板降低了80元/m~3,较UF板的成本增加了约100元/m~3。 相似文献
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依照JJF 1059.1-2012《测量不确定度评价与表示》的方法,对浸渍纸层压木地板内结合强度测量试验中影响其测量结果不确定度进行了分析和评定。结果表明：浸渍纸层压木地板内结合强度为：σ=（1.04±0.01）MPa,其中扩展不确定度的包含因子k=2,置信概率p=95%。 相似文献
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以磷酸二氢铵（MAP）溶液为阻燃剂,通过浸泡尾叶桉单板,研究了单板的载药量;以Ⅱ类胶合强度为指标,利用正交试验对常规胶合板生产工艺进行了优选。在此基础上,选取浸泡时间和最优生产工艺试制了阻燃桉树胶合板,并对其Ⅱ类胶合强度和燃烧性能进行了检测。结果表明：不同厚度尾叶桉单板的载药量随浸泡时间的延长呈现相似的增长规律;试验所得常规尾叶桉胶合板最优生产工艺为施胶量210 g.m-2、热压温度130℃、热压时间8 min,该条件下胶合板的Ⅱ类胶合强度达到了2.01 MPa;单板浸泡8h后,单板平均载药量为32.05 kg.m-3,所制得阻燃胶合板氧指数提高了13.9%,炭化长度减少了8.3 mm（26.2%）,阻燃性能明显提高,而胶合强度也达到了Ⅱ类胶合板的国家标准。研究初步证明利用常规桉树胶合板生产工艺生产阻燃桉树胶合板是可行的。 相似文献
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对废水中的磷用钼蓝分光光度法进行了测量,对测量过程的不确定度进行了分析,找出了影响不确定度的因素,对不确定度进行评估,给出不确定度,以如实反映测量的置信度和准确度,提出了在检测过程中应采取一些技术改进措施。 相似文献
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本文依据国家标准GB/T14074—2006,用滴定法测量脲醛树脂中游离甲醛含量,详细分析了测量过程中的各个影响因素,对检测结果的不确定度进行了评定,在测量过程中,重复性对不确定度贡献比较大。 相似文献
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Uncertainty in eddy covariance measurements and its application to physiological models 总被引：1，自引：0，他引：1
Flux data are noisy, and this uncertainty is largely due to random measurement error. Knowledge of uncertainty is essential for the statistical evaluation of modeled and measured fluxes, for comparison of parameters derived by fitting models to measured fluxes and in formal data-assimilation efforts. We used the difference between simultaneous measurements from two towers located less than 1 km apart to quantify the distributional characteristics of the measurement error in fluxes of carbon dioxide (CO2) and sensible and latent heat (H and LE, respectively). Flux measurement error more closely follows a double exponential than a normal distribution. The CO2 flux uncertainty is negatively correlated with mean wind speed, whereas uncertainty in H and LE is positively correlated with net radiation flux. Measurements from a single tower made 24 h apart under similar environmental conditions can also be used to characterize flux uncertainty. Uncertainty calculated by this method is somewhat higher than that derived from the two-tower approach. We demonstrate the use of flux uncertainty in maximum likelihood parameter estimates for simple physiological models of daytime net carbon exchange. We show that inferred model parameters are highly correlated, and that hypothesis testing is therefore possible only when the joint distribution of the model parameters is taken into account. 相似文献
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In this study, N-hydroxymethyl acrylamide (NMA) and vinyl acetate (VAc) were used in order to prepare secondary emulsions; additionally urea was then introduced into the polymerization to form ternary emulsions, adjusting different proportions of the three components. Compared to pure polyvinyl acetate, these two emulsion types presented shorter curing time, improved water resistance, and higher bond strength; this is based on the crosslinking ability introduced by the NMA, enabling such a partial crosslinking already during the polymerization process and during storage. The viscosity, solid content, storage stability, curing and drying behavior, water resistance, delamination time, and bond strength were influenced by the proportions of NMA and urea in the two systems. Urea had a positive effect on the wet bond strength, but a negative effect on the dry bond strength. The proportion of NMA and of urea during the polymerization preferably was 1–2 % based on VAc. 相似文献
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Axially loaded glued-in hardwood dowels 总被引：4，自引：0，他引：4
J. L. Jensen A. Koizumi T. Sasaki Y. Tamura Y. Iijima 《Wood Science and Technology》2001,35(1-2):73-83
The failure load of axially loaded hardwood dowels glued-in parallel to the grain direction of the jointed timber parts is
considered. Two simple theoretical solutions using linear elastic fracture mechanics/ideal plasticity and linear elastic stress
analysis, taking into account the finite shear stiffness of the bond line are, presented and compared with experimental results.
Theory shows that bond line shear strength is the governing strength property for ductile joints and fracture energy is the
governing strength property for brittle joints. Bond line shear strength and fracture energy are determined by means of curve-fitting.
Received 24 April 1997 相似文献