基于噪声温度计的铟凝固点热力学温度研究

热力学温度研究表明,国际温标ITS-90定义的一系列固定点与真实热力学温度有一定差异。以量子电压标定的噪声温度计为基础,设计了用于铟凝固点测量的温度探测装置,解决了高温复杂环境下电磁干扰的抑制问题。实验采用研制的噪声温度计系统测量了铟凝固点的热力学温度,测量积分时间100h,在20～500kHz的测量带宽内得到的铟凝固点热力学温度为429.7476K,相对不确定度为11.58×10^-6,与ITS-90给出的铟凝固点值相差0.9mK。实验结果可以为国际温标的修订提供参考。     

有效亮度温度测量中发射率影响的修正

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。     

Measurement of Thermodynamic Temperature Above the Silver Point on the Basis of the Scheme n?=?2

In this article, a practical n = 2 scheme, fitting into the ??Mise en pratique for the definition of the kelvin?? (MeP-K) at high temperature: MeP-K-HT is presented. It is made up by selected, intertwined pairs of reference points with one common lower reference point, the copper point, all in all constituting a main range and five associated subranges. The upper reference point associated with a given subrange can be chosen in conformity with the application. As will be shown, the proposed scheme has the following advantages when disseminating and measuring T: high intrinsic robustness, flexibility in coverage of temperature??in conformity with the application??effectiveness in terms of accuracy, and efficiency in terms of expenditure. The n = 2 scheme, as proposed, would be a good candidate for an officially endorsed successor or at least an endorsed complement to ITS-90 above the silver point. This would not exclude any other scheme in conformity with the MeP-K-HT being put into practice, like??reversing the argument??the still officially endorsed ITS-90 is to be allowed for the time being as one of the means for implementing MeP-K-HT.     

一种可同时测量发射率及温度的被动式测温系统

介绍了一种实用化实时测温系统.该系统采用了PIN硅光电二极管作光接收器件,由光学接收系统、信号放大与处理系统及显示系统三部分组成.从系统的相对测温灵敏度及探测器的温度分辨率与波长间的关系出发,结合大气对红外辐射的透射特性,确定了系统的工作波长;从系统的抗反射辐射能力出发,并结合探测器的最小可探测光功率要求,确定了系统的波长带宽.从辐射能P1、P2的测量不确定度出发,讨论了待测目标的发射率及温度的测量精度.结果表明,当λ=0.80 μm、△λ=20 nm时,在测温范围600～2 500℃内,系统的测温不确定度优于0.3%,满足设计要求.     

有效亮度温度理论

经典亮度温度和有效波长理论忽略了环境辐射的影响,且实际测温理论偏离了亮度温度的定义.考虑了环境辐射影响,提出新的有效亮度温度概念,使有效亮度温度适用于存在环境辐射的任意温度测量;进一步提出了基于带通辐射温度计测量的积分有效亮度温度和等效波长理论,使辐射温度计的"主观"测量结果与物体的客观辐射特性相联系,避免了实际测量理论偏离被测量定义.     

Uncertainties in the Realization of Thermodynamic Temperature Above the Silver Point

Recent advances in high-temperature thermometry have opened up the possibility of realizing and disseminating thermodynamic temperatures above the silver point by means of both primary radiometry and radiation thermometry with the aid of high-temperature fixed points with known thermodynamic temperatures. A variety of realization schemes, denoted n = 0, 1, 2, 3, 3+, where n refers to the number of fixed points used in the realization, are described in new sections of the ??Mise en pratique for the definition of the kelvin.?? A major advantage of this approach is flexibility, accommodating the varying resources and needs of a wide range of laboratories and/or users. This article outlines the uncertainty analysis for each of the n ?? 0 schemes, which provides a means for assessing the suitability of any particular scheme and for selection of the appropriate fixed points. In all cases, the analysis is based on a modified Sakuma?CHattori model of the radiometer response. This model allows simple analytical expressions to be derived for all sensitivity coefficients, identification of the dominant uncertainty components, and each scheme to be easily compared. Current best estimates for each uncertainty component are given, and these are propagated to give a total uncertainty for each scheme.     

高纯无水InCl3反应热力学机理

通过直接氯化法,制备高纯无水InCl3,得到实验最佳反应温度为600 ℃。以热力学平衡计算为理论依据,用吉布斯自由能函数和平衡分压对体系中的反应方向和限度进行数据分析,确定不同温度下反应得到的理论产物,并通过分子动力模拟计算,进一步揭示体系中反应温度和反应机理的关系。理论计算结果表明,在反应温度为665 ℃以下时,In与Cl2反应生成In2Cl6后再分解为InCl3和其他副产物,在反应温度为665 ℃以上时,可直接得到主要产物InCl3;而实验结果与理论计算存在的65 ℃误差,说明反应过程中平衡状态与非平衡状态间存在差异。     

单圆柱微波谐振法测量热力学温度的研究

利用氩气的量子力学“从头算”理论和相关实验测量结果,基于圆柱微波谐振法建立了气体折射率热力学温度计实验系统,测量了253~303 K范围内的热力学温度。通过测量圆柱微波谐振腔内4个横磁模式的微波谐振频率,获得了氩气在700 kPa附近的气体折射率,不同微波模式得到的氩气折射率一致性优于1×10^-8,进一步结合氩气的维里状态方程得到热力学温度。热力学温度T和ITS-90国际温标T90差异不确定度为11.6 mK,与国际温度咨询委员会的评估值具有良好的一致性。未来随着氩气理论计算和实验系统压力测量不确定度的深入研究,该方法测定热力学温度的不确定度会进一步改善。     

Adiabatic Calorimetry Approach to Assess Thermal Influences on the Indium Melting Point

Within the framework of the Euramet project 732, LCM/LNE-CNAM has recently proposed a new device to investigate the melting point of indium (156.5985 °C) by the way of an adiabatic calorimetry approach. An apparatus based on a cell-within-cell configuration was developed and experimentally tested. First results highlighted parasitic heat flows due to the geometrical characteristics of the cell, disturbing significantly the isothermal condition within the calorimeter. Such thermal effects were also clearly identified with a specific numerical model developed for this purpose. Considering the remarkable agreement between the model and relevant experiments, an optimization step has been carried out to design a suitable cell geometry. A new enhanced cell was subsequently fabricated and arranged within the calorimeter (indium load of 122.32 g). The purpose of this article is to introduce the thermal behavior of such a highly effective apparatus, while presenting some series of measurements; on the one hand, the melting point of indium under adiabatic conditions is studied, and on the other hand, the so-called continuous heat flow method under isothermal conditions is worked out. The obtained results are discussed and analyzed according to the impurity concentrations into the ingot (sum of individual estimate method).     

Measurement of Melting Point and Radiance Temperature (at Melting Point and at 653 nm) of Hafnium-3 (wt. %) Zirconium by a Pulse Heating Method

A subsecond duration pulse heating method is used to measure the melting point and radiance temperature (at 653 nm) at the melting point of hafnium containing 3.12 weight percent zirconium. The results yield a value of 2471 K for the melting point on the International Practical Temperature Scale of 1968. The radiance temperature (at 653 nm) of this material at its melting point is 2236 K, and the corresponding normal spectral emittance is 0.39. Estimated inaccuracies are: 10 K in the melting point and in the radiance temperature, and 5 percent in the normal spectral emittance.     

基于仿人智能的煤的燃点测定

提出基于仿人智能技术的煤的燃点测定新方法。为克服电炉数学模型大范围变化的问题,采用仿人智能控制算法设计了炉温控制器。运用仿人智能技术识别煤的燃点,这种方法吸收了人工识别时逻辑推理的长处,克服了人工识别的主观随意性。实验结果表明,其测量平行误差小于1℃,适合于用氧气作氧化剂时煤的燃点测定。     

高精度复现铟凝固点

利用金属外壳密封铟点容器,采用连续热流密度法,高精度复现了铟熔化温坪和凝固温坪.通过线性拟合方法确定铟的液相温度,并将其与凝固温坪最大值之间的差异作为评判铟点容器质量的重要依据.实验结果表明:液相温度和凝固温坪最大值之间的差异在0.27 mK范围内一致;距离容器温度计阱底部16 cm内垂直温场均匀度为13 mK.因此,...     

点导纳法的模态密度测试试验

模态密度能反映结构系统振动能量的存储能力,是应用统计能量分析法研究中高频动响应问题的重要参数。模态密度的实验获取常采用激励点导纳法。基于点导纳法原理,分别采用脉冲锤击和正弦扫频两种激励形式,测试一矩形铝合金板的模态密度,考虑传感器的附加质量,对测试结果进行修正。结果表明,激励形式对矩形铝合金板的模态密度的测试精度有较大影响;传感器的附加质量在不同激励形式下,相同频段内,对识别结果影响的差异明显;经过附加质量修正后,正弦扫频激励测试结果与理论值吻合性较好。     

NMIJ Constant-Volume Gas Thermometer for Realization of the ITS-90 and Thermodynamic Temperature Measurement

The constant-volume gas thermometer (CVGT) of the National Metrology Institute of Japan (NMIJ), AIST with ³He as the working gas is used as an interpolating gas thermometer to realize the International Temperature Scale of 1990 (ITS-90) from 3 K to 24.5561 K and as a relative gas thermometer for thermodynamic temperature measurement calibrated at the triple point (TP) of Ne. The standard uncertainties of the realization and measurement are estimated to be 0.58 mK and 0.86 mK at a maximum in the mentioned temperature range, respectively. The maximum difference between both temperatures is about 1 mK. In the calibration of the CVGT, the TP of equilibrium hydrogen (e-H₂) is corrected for isotopic composition as specified in the Technical Annex for the ITS-90. The ambiguity of the TP of Ne due to the variability in isotopic composition is included in the uncertainty. Although the CVGT was also used in 2004 to realize the ITS-90, it was modified for the present experiment to reduce some measurement uncertainty components and the working gas was replaced with a higher-isotopic-purity gas. The results from 2004 were recalculated by correcting for the isotopic composition of e-H₂ and differ insignificantly from the present results, except for a wider scatter.     

Thermodynamic Temperature Measurements Traceable to Photometric Standards

The replacement of ITS-90 temperature measurements by direct thermodynamic temperature measurements based on radiometric techniques in the temperature range above 1000 °C has been proposed by many national measurement laboratories. This article reports on work at NMIA to develop a simple and robust traceability scheme for thermodynamic temperature, based on the use of photometers and a Thermogage furnace with a graphite tube element modified to improve its temperature uniformity and emissivity. A simple luminance meter was constructed using a commercial photometer and pairs of precision apertures to view the rear of the blackbody cavity. This photometer was calibrated against NMIA reference illuminance lamps, and relative spectral responsivity measurements were used to determine the color-temperature correction between the lamps and the Thermogage blackbody. Thermodynamic temperature determinations made using various combinations of apertures and photometers showed a range of less than 0.2 °C at 1700 °C, consistent with the calculated uncertainty of 0.29 °C (k = 2). ITS-90 measurements made by NMIA??s LP5 and HTSP primary radiation thermometers with an uncertainty of 0.16 °C (k = 2), are consistent with the thermodynamic measurements. It is suggested that routine thermodynamic temperature determinations can now be made with an effort comparable to that required to realize the ITS-90 above 1000 °C.     

Realization of the Indium Fixed Point by an Adiabatic Technique

This work investigates the effect of heating techniques on the realization of the ITS-90 fixed points above room temperature. For that purpose, LNE has constructed a new apparatus to realize the indium fixed point under adiabatic conditions using the “calorimetric” method. The adiabatic condition, in general, is established by maintaining a temperature difference between the fixed-point cell and its surroundings that is as small as possible. In this work, the indium fixed-point cell is located within thermally controlled heat shields whose walls also contain indium. Thus, the shields themselves are also indium cells. The experiments realizing the melting and freezing temperatures of indium using the calorimetric method are described. The results revealed the existence of thermal effects in the realization of the indium fixed-point cell by the conventional “continuous heat flux” method. The advantages of the “cell-within-cell” technique are presented.     

多种体温测量方法的比较

本文采用三种不同的体温测量方法,收集89例患者的体温,每种方法各收集到有效数据845个.通过对体温数据的处理分析,探索耳温、额温、肛温三者的关系.额温均数标准差:(37.12±0.32)℃;耳温的均数标准差:(37.37±0.47)℃;肛温的均数标准差(37.53±0.31)℃.     

CO2低温蒸发过程的热力分析与比较

通过对CO2与几种常用低温制冷剂蒸发过程的热力分析与比较，得出自然工质CO2亚临界循环具有明显的优势，应用于超市等商用制冷系统的低温循环，具有很好的应用前景。