共查询到19条相似文献,搜索用时 109 毫秒
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现行的辐射温度计检定规程,概念不够清晰,具体操作步骤描述过于简单,造成检定的实际测量条件有明显的差异,由此导致检定结果的差异。本文从技术角度出发,提出了一种可行的操作方法,力图提高辐射温度计检定结果的准确度。 相似文献
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用典型红外辐射温度计的辐射源尺寸效应的实验数据说明不同测量条件下的检定/校准结果的差异可能为其最大允许误差绝对值的数倍。提出具有明确测量条件的平面辐射源瞄准模型和以辐射源前置光阑的方式对于不同空腔黑体辐射源实现相同的等效平面源直径的方法,提出了对光阑的技术特性和放置距离要求,分析表明低温辐射源对光阑的冷却作用可能引起不可忽略的示值降低。采用等效平面源模型的实验结果表明以不同几何条件的空腔黑体辐射源可得到一致的检定结果。讨论了应用平面辐射源模型可能遇到的实际技术问题和解决的对策。 相似文献
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经典的短波高温修正模型不适用于中长波红外温度计的发射率修正和不确定度评定。采用有效亮度温度概念,得到了对于温度范围和测温波长具有广泛适用性的发射率影响模型以及具有简明物理含义的微差近似形式,包含了经典亮度温度理论中的发射率影响修正和环境辐射误差修正。定量分析了经典的短波高温修正模型的误差。针对黑体辐射源的不同溯源方法,讨论了辐射温度计校准中的发射率影响修正方法,并给出修正实例。所用方法可用于辐射测温应用、辐射温度计校准和黑体辐射源校准中的发射率和环境影响修正以及辐射源发射率不确定度对校准结果不确定度贡献的计算。 相似文献
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If a radiation thermometer is calibrated by measuring the temperatures of two cavities having different geometries, sometimes
discrepancies arise between them, even though their emissivities are close to that of a blackbody. The origin of such discrepancies
may result from the size-of-source effect, and in the distance-to-target effect for those thermometers that offer focusing
capability. Examples include: (a) out-of-focus image changes the reading: different focus settings produce different results
and (b) measurements taken at different distances produce different results. These effects are discussed, their contribution
to the measurement uncertainty is evaluated, and some recommendations are made for practical blackbody cavities or radiators
to reduce such effects. 相似文献
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热物理性质测试技术研究现状和发展趋势 总被引:3,自引:0,他引:3
本文在对热物理性质研究在热能工程、材料科学、信息科学、航天工程、环境工程、生物科学、微电子技术和计量学等众多科技领域中的重要性进行探讨的基础上,评述了热物理性质测试技术的研究现状和发展趋势。鉴于薄膜材料在微电子器件、集成电路和微电子机械系统等领域中日益广泛的应用,本文还综述了亚微米-纳米尺度薄膜材料热导率和热扩散率的测试新技术。 相似文献
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针对关节式坐标测量机(ACMM)在大尺寸工件的检测过程中测量范围有限且误差较大的问题,提出了一种基于距离约束的ACMM的蛙跳测量方法。在ACMM进行坐标转换的过程中,利用蛙跳球作为公共基准点,用高精度的三坐标测量机对蛙跳球之间的空间位置关系进行标定。在计算坐标转换参数的过程中,将任意两蛙跳球之间的位置关系作为距离约束条件,消除测量过程中产生的粗大误差并优化坐标转换模型的参数,以提高坐标转换精度。实验结果表明:距离约束能够有效地提高坐标转换参数的精度,同时增加公共基准点的个数会较大地提高蛙跳测量精度。 相似文献
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The article evaluates the uncertainty in the temperature indicated by a radiation thermometer with a direct readout in temperature,
due to the uncertainty in measuring the size-of-source effect (SSE) by the so-called “direct method.” Radiation thermometers
of this type are the ones most frequently used in practice. The uncertainty of the SSE characteristic is usually not a useful
quantity to report to users of commercial radiation thermometers. Instead, they would prefer to know the uncertainty in the
measured temperature that results from the uncertainty of the SSE characteristic, and this will be the result of our analysis.
The user of a direct reading radiation thermometer will be able to take into account the uncertainty of temperature due to
the SSE, if a target with known dimensions is measured. The uncertainty in temperature due to the SSE of analyses based on
Planck’s law and its approximation, Wien’s law is compared. 相似文献
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The knowledge of \(\sigma _{d}\), the parameter that measures the size-of-source effect of a radiation thermometer, as a function of the diameter d of a radiation source is mandatory to estimate the appropriate corrections to temperature values measured when aiming to radiation sources of different sizes. To obtain \(\sigma _{d}\) as a function of d is a complicated task because there is no universally recognized mathematical function that relates them. The direct method to evaluate \(\sigma _{d}\) usually requires a radiation source of appropriate size and a set of many diaphragms with increasing diameter. How good is the approximation to \(\sigma _{d}\) estimated in this way depends on the number of diaphragms used. To reduce the time and cost to evaluate \(\sigma _{d}\), it is desirable to have methods that provide good approximations with a reduced number of diaphragms. In this paper, we present a method to obtain an approximation to \(\sigma _{d}\) as a function of d with a limited number of diaphragms. When using this method, deviations of less than \(1\;{^{\circ }}\hbox {C}\) are obtained when measuring radiance temperatures of \(500\;{^{\circ }}\hbox {C}\), between the measured temperatures and those calculated from values of \(\sigma _{d}\). We also propose a simple equation to interpolate approximated values of \(\sigma _{d}\) for those diameters between those used in its evaluation, but a limitation is that \(\sigma _{d}\) must be bigger than 0.98. 相似文献