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51.
The aim of the study was to compare the performances of the Brungraber Mark II (BM II) and Mark III (BM III) slipmeters. Friction measurements with the two slipmeters were conducted in a laboratory using four footwear materials, four floor types, and three surface conditions. Both the coefficient of friction (COF) values obtained with the slipmeters and the force platform-based COF values were measured. The COF measured with the BM II was slightly higher than that measured with the BM III with a R2 of 0.83. A comparison of the averaged normal force between the two slipmeters showed that the BM II generated a significantly higher normal force than the BM III at a low COF and the difference of the normal force between the two slipmeters decreased when the COF value was increased. The regression analysis results in this study showed that the force platform-based COF values were closer to the COF values obtained with the BM III than with the BM II. The R2 values for the regression model between the COF values obtained from the slipmeter and the force platform were 0.90 and 0.79 for the BM II and BM III, respectively. 相似文献
52.
热真空设备中与温度相关的试验技术探讨 总被引:1,自引:0,他引:1
以RZHM-1400-AB型热真空试验箱为实例,简述设备主要工作原理。强调其温度传递方式及航天产品在热真空试验中温度参数的重要性。以无数试验数据为依据,着重论证何种类型测温传感器与实际设备相匹配,同时论证选取何种外形的测温传感器为最佳温度测量工具。同时,进一步介绍几种在热真空试验中使用这些测温传感器的方法,以减少不必要的人为测量误差。 相似文献
53.
锶盐废渣含硫状态分析及硫含量的测定 总被引:1,自引:0,他引:1
锶盐废渣中硫的状态及含量不同其作用大不相同,有的呈现活性导致膨胀破坏,而有的则表现为惰性,因此有必要了解硫的存在状态及含量。分析表明锶盐废渣中硫主要以硫酸盐硫(SO3)和硫化物硫(S2-)两种形式存在。选择硫酸钡重量法和碘量法进行化学测定,然后用X-射线能谱仪进行元素定性分析;并将化学分析和仪器测定两种方法进行对比。结果表明,X-射线能谱法可以快捷、方便地探测锶渣所含各种元素,但不能确定元素的价态;化学分析方法可得到相对准确的元素含量;用硫酸钡重量法和碘量法联合测定锶渣中的硫含量,与X-射线能谱法相比,偏差仅为0.37%。 相似文献
54.
三维脚型测量技术及方法的研究 总被引:1,自引:0,他引:1
本文阐述了人体脚型的测量方法及特点,比较后得出人工测量与三维扫描测量技术之间的差别。以YETI三维脚型扫描仪为模型,详细分析了脚型扫描仪的结构原理,摸索并提出了简单实用的测量方法,讨论了YETI三维脚型扫描仪获得的原始数据、脚型横截面以及脚型投影图的特点。 相似文献
55.
Indicators are used to draw conclusions about ecological endpoints when these endpoints cannot be measured directly. In many cases, inferences about an endpoint are only possible because assumptions have been made about the relationship between indicator and endpoint; we refer to such indicators as judgement indicators. The validity of inferences made using a judgement indicator can be gauged by examining the known or assumed form of the general relationship between indicator and endpoint. The rules for this kind of inference are a consequence of scale invariance, which originates from measurement theory. For simple indicators comprised of a single indicator measurement, the inferences allowed – equivalence, rank, equality of intervals, and equality of ratios – depend on whether the data are nominal, ordinal, interval, or ratio scaled. For composite indicators containing two or more simple indicators, inferences are also affected by the mathematical form of combination; e.g., whether the terms are summed or multiplied. Standardizing simple or composite indicators can allow inferences about the relative importance of observations, based on the natural range of occurrence. Scale invariance is a particularly important consideration in landscape assessments, since these often make use of judgement indicators. 相似文献
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Thomas A. Fontaine 《Journal of the American Water Resources Association》1991,27(3):509-520
ABSTRACT: The areal mean precipitation (AMP) over a catchment is normally calculated using point measurements at rainfall gages. Error in AMP estimates occurs when an insufficient number of gages are used to sample precipitation which is highly variable in space. AMP error is investigated using historic, severe rainfalls with a set of hypothetical catchments and raingage networks. The potential magnitude of error is estimated for typical gage network densities and arrangements. Possible sources of error are evaluated, and a method is proposed for predicting the magnitude of error using data that are commonly available for severe, historic rainfall. 相似文献
60.
介绍了1993年获得的两个中等地震震例的情况,并以此验证据以往震例总结出的预报公式。验证的结果与实际符合较好。另外,文中指出了该手段的主要优点及克服其缺点的可能途径,即有些台站可采用地磁等变线差值法处理。 相似文献