A thermal model of the phase transition of a high-temperature eutectic in a cylindrical vessel

A model to describe the phase transition of a material enclosed in a cylindrical vessel is constructed. Different methods of determining the phase-transition temperature are compared. The method of determining the temperature at a point situated at the end of the linear part of the temperature-time graph has the highest accuracy. __________ Translated from Izmeritel’naya Tekhnika, No. 6, pp. 53–55, June, 2007.     

The Realization of Fixed Points of the Temperature Scale in Small-Size Ampoules

Results of an investigation of small-size ampoules of the fixed points of gallium and indium are described. It is concluded that they can be used as an inexpensive standard means of measuring temperature.     

Fixed points as part of the KT-500 and KT-650 temperature calibrators

The results of a measurement of the indium, tin, and zinc fixed points in the KT-500 and KT-650 temperature calibrators are presented. It is shown that the error in reproducing the temperature does not exceed 0.003°C for indium and tin and 0.014°C for zinc. It is concluded that it is possible to use these points to check second-class and third-class standard resistance thermometers. __________ Translated from Izmeritel’naya, Tekhnika, No. 6, pp. 57–59, June, 2007.     

Approximating the ITS-90 between Zinc and Copper with an Infrared Thermometer at NIS-Egypt

This paper presents an approximation to the International Temperature Scale of 1990 (ITS-90) between the Zn (420 °C) and Cu (1085 °C) fixed points using a 900 nm narrow-band radiation thermometer. This thermometer has a 400 mm working distance and a 150 mm objective focal length. An image of the measured target is focused by the objective lens onto a 1 mm aperture (drilled mirror). The light passing through the aperture is conveyed by a condenser lens through an interference filter with a nominal central wavelength of 900 nm and a half-bandwidth of 10 nm before reaching a silicon photodiode working in the photovoltaic mode. The thermometer was calibrated at the Zn, Al, Ag, and Cu blackbody fixed points. The results of the calibration were used to determine the constants A, B, and C of the Sakuma-Hattori interpolation equation. The results showed that the ITS-90 can be approximated within ± 0.051 °C throughout the Zn-Cu interval when the thermometer is calibrated at the Zn, Al, Ag, and Cu fixed points.     

Ga-In共晶固定点复现及赋值研究

次级固定点进一步分度温度计应用于温度校准已成为减小温度量值传递不确定度的重要方法.围绕Ga-In二元合金,以高复现水平为目标,详细介绍了大尺寸固定点容器研制、固定点灌注过程,开展了固定点复现性、亚配比剩余镓温坪验证实验研究;采用了切线交点法、均值法、三次多项式拟合法3种相变温度取值方法对Ga-In固定点进行了评价和分析...     

Ga-In-Sn微型共晶点相变特性研究

以Ga-In-Sn三元合金为研究对象,研制了可用于现场及在线标定的微型Ga-In-Sn共晶点容器,开展了3种不同配比对相变温度和温坪复现影响的研究。结果表明:3种配比的共晶点温坪可持续1.2~2 h,实验的复现性优于4.5 mK,合成扩展不确定度为9.3 mK(k=2),3种配比的共晶点相变温度平均值为10.748 ℃;在相同热工况下Ga-In-Sn合金发生共晶反应的相变温度不受配比的影响;改变合金熔体的降温速率可改变微型共晶点过冷度。     

Bi-In-Sn合金熔化温坪优化方法探索

为了提高红外遥感高精度测量水平,研发适用于红外遥感测温范围的次级固定点已成为提高在轨温度标定精度的重要手段.针对红外遥感领域涉及的温度范围(190～350 K),研制了Bi-In-Sn三元合金固定点.为提高三元合金温坪复现水平,采用预熔方法对三元合金固定点进行预处理,分析不同热工况对三元合金温坪的影响,获得适用于该三元...     

Fixed point on the basis of Ga-In eutectic alloy for rapid monitoring of thermometers and temperature measurement systems

A fixed point based on Ga-In eutectic alloy with a phase transition temperature of 288.798 K (15.648°C) is proposed and studied. This temperature makes it possible to accomplish a phase transition without the use of external thermostat devices. __________ Translated from Izmeritel’naya Tekhnika, No. 5, pp. 26–30, May, 2008.     

A method for indirect measurements of the parameters of platinum resistance thermometers at the freezing point of silver

A procedure for reproducing the International Temperature Scale ITS-90 for solving special measurement problems is considered.Translated from Izmeritelnaya Tekhnika, No. 11, pp. 46–49, November, 2004.     

高温共晶点坩埚耐用性研究

高温共晶点坩埚因采用石墨材料制作,结构强度较低,在复现试验后易发生破裂,造成高温共晶点的损坏。坩埚耐用性问题已成为制约高温共晶点加入下一代温标的主要障碍之一。为了解决上述问题,本文依据ANSYS对坩埚受力情况进行分析,明确了坩埚主要受力点的理论位置,之后结合多种高温共晶点的实际破裂情况,分析了不同种类共晶点坩埚破裂的原因,并有针对性的提出了两种高温共晶点坩埚改进方案：改进型Hybrid结构和导流盖结构。最后使用改进结构的坩埚灌注了新的高温共晶点/包晶点,复现试验后未出现损坏问题,初步验证了方案的有效性。     

Large scale cathodic exfoliation of graphite using deep eutectic solvent and water mixture

A short-time and low-cost synthesis route was used to produce large lateral size (from 2 to 15 μm) from monolayers to few layers of graphene by a two-step process of electrochemical exfoliation with a deep eutectic solvent in a mixture with water that can be reused, and ultrasonic bath. The graphene was characterized by SEM, TEM, AFM, Raman and electrochemical activity. During the electrochemical exfoliation, high expanded graphene particles were obtained and these were dispersed in a mixture of water with 5%wt ethylene glycol by an ultrasonic bath in order to complete the exfoliation process. An enhancement of the electrical conductivity of these dispersions was obtained with the increase of graphene concentration, 0.38 mg/mL, which best result was achieved with 30 wt% water and a DC voltage of 10 V. It was possible to add a conductive layer to a glass substrate with the graphene obtained and Tyndall effect was observed.     

The Dutch National Realization of the ITS-90 over the Range 13.8033 K–273.16 K

The facility constructed at NMi VSL to realize the ITS-90 in the capsule standard platinum resistance thermometer range (CSPRT, 13.8033–273.16K) is presented. To demonstrate the performance of our facility, the results of a recent measurement campaign are reported, in which 3 NMi VSL CSPRTs were calibrated in the range 13.8–273.16K at all of the fixed points required by the ITS-90. The uncertainty of the calibration of the CSPRTs at each of the fixed points is evaluated in accordance with the most recent recommendations of the Consultative Committee for Thermometry and its Working Groups 1 and 3.     

Realization of the Gallium Triple Point at NMIJ/AIST

The triple point of gallium has been realized by a calorimetric method using capsule-type standard platinum resistance thermometers (CSPRTs) and a small glass cell containing about 97 mmol (6.8 g) of gallium with a nominal purity of 99.99999%. The melting curve shows a very flat and relatively linear dependence on 1/F in the region from 1/F = 1 to 1/F = 20 with a narrow width of the melting curve within 0.1 mK. Also, a large gallium triple-point cell was fabricated for the calibration of client-owned CSPRTs. The gallium triple-point cell consists of a PTFE crucible and a PTFE cap with a re-entrant well and a small vent. The PTFE cell contains 780 g of gallium from the same source as used for the small glass cell. The PTFE cell is completely covered by a stainless-steel jacket with a valve to enable evacuation of the cell. The melting curve of the large cell shows a flat plateau that remains within 0.03 mK over 10 days and that is reproducible within 0.05 mK over 8 months. The calibrated value of a CSPRT obtained using the large cell agrees with that obtained using the small glass cell within the uncertainties of the calibrations.     

The Influence of Antimony on the Tin Point

In 2005, an agreement was reached on how to estimate uncertainties and how to correct fixed-point temperatures for the influence of chemical impurities. Although the general procedure is now specified, some problems remain. The slope of the liquidus line at very low-impurity concentrations must be extracted either from binary-phase diagrams or from doping experiments. Apart from this, there is little experimental evidence to prove that the models used to characterize the freezing and the melting plateaux are adequate, especially for impurities that increase the fixed-point temperature. Therefore, a series of measurements were carried out using a tin fixed-point cell doped with antimony. By varying the freezing and the melting conditions, some useful experimental data were collected.     

-38.8344~156.5985℃温区温标偏差方程外推和内插研究

根据90国际温标定义,对0~29.7646℃和-38.8344~29.7646℃两个子温区偏差方程使用范围的外推进行研究,给出了-38.8344~156.5985℃温区的新偏差方程,采用15支和23支标准铂电阻温度计的标定数据对偏差方程的外推和新方程进行验证。结果表明:在0~29.7646℃与-38.8344~29.7646℃温区内的偏差方程分别外推到100℃与-80℃时,外推结果与温标偏差方程计算结果的最大差值为1.1 mK与2.6 mK,新的偏差方程在1.5 mK内与温标定义偏差方程等效,两个子温区偏差方程使用范围外推及新偏差方程在一定程度具备可行性。     

深过冷Ni-Sn合金非规则共晶的形成机制

采用熔融玻璃净化配合循环过热使Ni-32.5%Sn(质量分数)共晶合金实现了深过冷快速凝固.当过冷度大于某一临界值时,非规则共晶在凝固组织中出现.随着过冷度的提高,最终得到完全的非规则共晶组织.通过分析Ni-Sn共晶合金中各相形核、生长、以及枝晶熔断机制随过冷度的变化,解释了非规则共晶的形成机制.在深过冷条件下熔体中初生相率先形核并长入过冷熔体中,形成枝晶骨架,再辉重熔后次生相从残余熔体中析出并包围初生相,形成非规则共晶.     

Apparatus for realizing the ITS-90 in the temperature range from the triple point of argon to the melting point of gallium

Systems for realizing the fixed points of the ITS-90 for calibrating column and capsule standard platinum thermometers, namely, the triple points of argon and mercury and the melting point of gallium, are constructed and investigated. The errors of the values of the metrological characteristics of the systems obtained enable one, using platinum resistance thermometers, to reproduce and transfer the temperature scale in the 83.8–302.9 K range. The extended uncertainty in reproducing the temperatures of the fixed points does not exceed 0.4 mK. This paper has been prepared from the contributions presented at the 3rd All-Russia Conference “Temperature 2007”; see the selection of papers in Measurement Techniques, Nos. 8 and 9, 2007. __________ Translated from Izmeritel’naya Tekhnika, No. 11, pp. 26–31, November, 2007.     

汞三相点的复现

利用自制的超高纯汞三相点容器,复现了1990年国际温标(ITS-90)中新设定的汞三相点。结果表明其融化范围和凝固范围均在0.1mK以内,复现性优于0.1mK,两者的符合程度也在0.1mK之内,分别用纯度为99.99999％的超高纯商品汞和实验室清洗的汞经高真空蒸馏制备的两个密封容器,测定结果在实验误差内一致,差异不大于0.1mK。文中介绍了三相点容器的制备工艺要点。     

高精度钾热管铝凝固点炉研制及性能测试

热管作为等温炉衬可提高固定点炉温场均匀性。为提高铝凝固点复现水平,研制了1套高精度钾热管铝凝固点炉。介绍了钾热管和固定点炉的研制流程,并测试了钾热管固定点炉性能。测试结果表明:采用分段升温的方式,炉子升温曲线平缓,整个升温过程中没有明显过冲现象,可有效保护铝凝固点容器的使用寿命;钾热管铝凝固点炉垂直温场均匀性为6.6mK;利用该钾热管铝凝定点炉可以实现铝凝固点温坪的复现,温坪重复性为0.02mK。     

PPRTs偏差方程外推至-189.3442~156.5985℃温区的研究

由于ITS-90定义固定点数量少且温度间隔大,基于偏差方程的外推是解决超出温区范围的温度计标定问题的有效方法。实验对16支精密铂电阻温度计在超出温区范围标定,验证了固定点法和比较法偏差方程从窄温区范围外推至-189.3442~156.5985℃温区的可行性。实验结果表明:-38.8344~0.01℃温区新偏差方程外推至 -189.3442℃ 的平均最大差值为5.2mK;0~29.7646℃温区偏差方程外推至156.5985℃的平均最大差值为 2.0mK;基于比较法的偏差方程在-189.3442~156.5985℃温区的平均差值小于3.3mK。3种方程均提高了精密铂电阻温度计在超出温区范围的外推精度,为星载黑体辐射源的量值溯源提供了数据支撑。