Progress Report on NMIJ Acoustic Gas Thermometry at the Triple Point of Water

Herein, progress in the development of an acoustic gas thermometry (AGT) system at the National Metrology Institute of Japan is reported. This AGT system is an initial low-cost version that uses a 1-l quasi-spherical resonator (QSR) made of oxygen-free copper. The system was tested by measuring the speed of sound in argon at the temperature of triple point of water. Measurements were conducted at ten different pressures, ranging from 60 kPa to 420 kPa. The ideal gas limit of the squared speed of sound was obtained through extrapolation, and a preliminary calculation of the Boltzmann constant, which was 12 ppm below the CODATA2014 value, was made. Large inconsistencies among microwave and acoustic modes were observed, which are dominant sources of uncertainty in speed of sound measurements. The system will be improved by replacing the present QSR with another one that is more precisely fabricated.     

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.     

Optical-Fiber Power Meter Comparison Between NIST and PTB

We describe the results of a comparison of reference standards between the National Institute of Standards and Technology (NIST-USA) and Physikalisch-Technische Bundesanstalt (PTB-Germany) at nominal wavelengths of 1300 nm and 1550 nm using an optical-fiber cable. Both laboratories used thermal detectors as reference standards. A novel temperature-controlled, optical-trap detector was used as a transfer standard to compare two reference standards. Measurement results showed differences of less than 1.5 × 10⁻³, which is within the combined uncertainty for both laboratories.     

Realization of the Triple Point of Water in Metallic Sealed Cells at the LNE-INM/CNAM: A Progress Report

A miniature metallic cell for the water triple point (TPW, temperature 273.16 K) was developed for capsule-type thermometer calibrations for realizations with adiabatic calorimetry techniques. The LNE-INM/Cnam previously developed a copper cell for the water triple point and the techniques for cleaning, filling, and sealing. On the basis of previous work, a new copper cell prototype for the TPW was developed and filled at the LNE-INM/Cnam. Measurements were performed using an appropriate calorimeter and a comparison block containing several thermometers. Preliminary results show a scatter of the temperatures measured at the phase transition of the order of 0.2 mK when measurements are repeated over a short-term period (1 month). A positive drift in the phase transition temperature of about 30μK·month⁻¹ was observed over several months. Studies are in progress to improve the cell, to reduce the reproducibility uncertainty to less than 0.1 mK and to have a phase transition with better temporal stability.     

A New Generation of Open Zinc Freezing Point Cells at TUBITAK UME

The Temperature Laboratory at TUBITAK UME initiated a study which focused on the construction of freezing point cells of ITS-90 as primary temperature standards. The first cell constructed within the scope of this study was an open tin freezing point cell and the results were in good agreement with the reference tin fixed point cell of UME. The second set of cells constructed was two open zinc freezing point cells. The design of these cells is similar to the tin freezing point cell. After construction, all the home-made cells were evaluated by analyzing their melting and freezing curves. Finally comparison measurements were performed between the current laboratory reference zinc cell and all newly constructed cells.     

Effect of Impurities on the Freezing Point of Zinc

The knowledge of the liquidus slope of impurities in fixed-point metal defined by the International Temperature Scale of 1990 is important for the estimation of uncertainties and correction of fixed point with the sum of individual estimates method. Great attentions are paid to the effect of ultra-trace impurities on the freezing point of zinc in the National Institute of Metrology. In the present work, the liquidus slopes of Ga–Zn, Ge–Zn were measured with the slim fixed-point cell developed through the doping experiments, and the temperature characteristics of the phase diagram of Fe–Zn were furthermore investigated. A quasi-adiabatic Zn fixed-point cell was developed with the thermometer well surrounded by the crucible with the pure metal, and the temperature uniformity of less than 20 mK in the region where the metal is located was obtained. The previous doping experiment of Pb–Zn with slim fixed-point cell was checked with quasi-adiabatic Zn fixed-point cell, and the result supports the previous liquidus slope measured with the traditional fixed-point realization.     

The Influence of Impurities on the Zinc Fixed Point

Impurities are considered to be the most significant source of uncertainty for the realization of the International Temperature Scale of 1990 by means of metal fixed points. The determination and further reduction in this uncertainty require a traceable chemical analysis of dissolved impurities in the fixed-point metal and accurate knowledge of the specific temperature change caused by impurities (slope of the liquidus line). We determined the slope of the liquidus line for three binary systems and present results and conclusions from the chemical analysis of zinc with a nominal purity of 7N. For the Fe–Zn system, we determined a liquidus slope of (\(-0.91\pm 0.14\)) mK / (\(\upmu \hbox {g}{\cdot }\hbox { g}^{-1}\)) from the evaluation of freezing plateaus and (\(-0.76~\pm 0.20\)) mK / (\(\upmu \hbox {g}{\cdot }\hbox { g}^{-1}\)) from the evaluation of melting plateaus; for the Pb–Zn system, the corresponding results are (\(-0.27~\pm 0.05\)) mK / (\(\upmu \hbox {g}{\cdot }\hbox { g}^{-1}\)) and (\(-0.26~\pm 0.05\)) mK / (\(\upmu \hbox {g}{\cdot }\hbox { g}^{-1}\)). Although for the Sb–Zn system, we determined a liquidus slope of about \(-0.8\) mK / (\(\upmu \hbox {g}{\cdot }\hbox { g}^{-1}\)), our investigations showed that a correction of the influence of antimony is highly questionable because antimony can be found in zinc in a fully dissolved state or precipitated as an insoluble compound. Iron is the only impurity where a correction of the fixed-point temperature was possible. For the realization of the zinc fixed point at PTB, this correction is between 2 \(\upmu \)K and 16 \(\upmu \)K depending on the batch of zinc used. The influence of the sum of all impurities was estimated by means of the OME method. The resulting uncertainty contribution is between 12 \({\upmu }\hbox {K}\) and 48 \({\upmu }\hbox {K}\).     

Study on the Realization of Zinc Point and the Zinc-Point Cell Comparison

Continuing our study on aluminum, tin, and silver points, a study on the realization of the zinc point was conducted. Zinc-point cells were newly fabricated using 6N-nominal grade zinc samples, impurity elements of which were analyzed extensively based on glow-discharge mass spectrometry (GDMS). The present paper reports the temperature measurements done using the newly fabricated cells during the zinc freezing process, under which the zinc fixed point is defined, and the analysis of the freezing curve obtained. Comparisons of zinc-point temperatures realized by the newly fabricated cells (cell-to-cell comparisons) were also conducted. Zinc-point depression due to impurity elements was calculated based on the sum of individual estimates and the impurity element analysis. One of the cells evaluated was drawn out from its crucible and analyzed by GDMS at four points, namely, at around the center of the top, of the middle, of the bottom, and around the outer part of the middle area. The purpose of this cell disassembly is to see whether or not there has been some difference before and after cell fabrication, as well as difference in impurity element distribution within the ingot. From the aforementioned studies, some findings were obtained. First finding is that the homogeneity of the zinc ingot was within 30%, except for Pb, which was more concentrated in the center part. Second finding is that the cell-to-cell temperature difference changes along with the progressing solidification process. As a consequence, for an accurate cell-to-cell comparison, the locus in the freezing plateau where the comparison is done should be determined. Third finding is that the slope analysis estimates accurately the cell-to-cell comparison, and is consistent with the impurity analysis. This shows that the slope analysis gives extensive information about the effect of impurity to the zinc-point realization, especially after the cell fabrication.     

Recent Progress of the 2e/h Measurement at PTB

In this paper, an experimental setup is described with which the stability of the PTB voltage standard, consisting of a group of International Weston cells, can be monitored with a total uncertainty (1?) of 4 parts in 108 by means of the ac Josephson effect. The measured quotient of the fundamental constants 2e/h is given by 2e/h = (483 593.606 ± 0.020) GHZ/VPTB, May 1972.     

Effect of Ultra-Trace Impurities on the Freezing Point of Zinc

Impurities are the most significant source of uncertainty in most metal fixed points for the realization of the International Temperature Scale of 1990 (ITS-90). The methods for the estimation of uncertainties and corrections of fixed-point temperatures attributable to the influence of chemical impurities were summarized in 2005, and the sum of individual estimates (SIE) method was recommended to be used with the known concentration and liquidus slope of each impurity. This method requires the concentrations and the liquidus slopes of all impurities. For applying the SIE method, efforts still need to be made to solve a series of problems including the unsatisfactory chemical analysis, inadequate data of the liquidus slopes, and information about the dissolution and precipitation of impurities during the filling and the operation of a fixed-point cell. In the present work at the National Institute of Metrology (NIM), great attention is paid to the effect of ultra-trace impurities on the freezing point of zinc. Five slim graphite crucibles were filled with the same batch of zinc with a nominal purity of 6 N for this research. One of them was used to investigate the concentration and distribution of the impurities in the freezing point of zinc by chemical analysis. The remaining crucibles were used to carry out the ultra-trace impurity doping experiments. The liquidus slopes of Ag–Zn, Pb–Zn, Fe–Zn, and Ni–Zn were measured. All results are reported and discussed.     

基于准绝热的锌固定点复现装置

ITS-90温标固定点温坪受到诸多方面的影响,温场是其中重要影响因素之一。为提升温场性能弥补漏热造成的影响,借鉴低温固定点中广泛采用的绝热原理,设计基于准绝热的锌固定点装置,温场梯度性能由传统固定点的100 mK提升至20 mK,固定点高纯金属使用量由2.0kg降至200 g。实验结果表明该装置的温坪可持续时间较长,复现性0.1 mK,既能大幅度提升温场性能,同时达到了装置小型化、可重复使用经济实用的目的,又为高纯金属中微量杂质对相变温度的影响评估降低温场因素的干扰提供研究基础。     

Rise-Time Calibration of 50-GHz Sampling Oscilloscopes: Intercomparison Between PTB and NPL

The paper presents the results of the first intercomparison of the rise-time calibration of a 50-GHz sampling oscilloscope between Physikalisch-Technische Bundesanstalt, Germany, and National Physical Laboratory, U.K. (EUROMET project 641). Rise-times between 6.0 and 6.6 ps were obtained using optoelectronic techniques. Detailed uncertainty budgets are given, which yield typical rise-time uncertainties of 1.2 ps. The absolute values of the degree of equivalence are les 0.3 ps with an expanded uncertainty of 1.0 ps and, thus, validate the experimental techniques     

金属杂质对锌凝固点容器融化温坪的影响

本文介绍了不同浓度杂质对锌凝固点容器融化温坪的影响,同时研究了在不同凝固速率下融化温坪的变化。研究表明,融化温坪的区别直接反映了杂质在融化过程中的分布,不同的凝固速率对锌凝固点容器融化温坪斜率影响较大。     

微量杂质对锌凝固点影响的评估

介绍了当前微量杂质对固定点影响的多种评估方法,将这些方法应用到中国计量科学研究院最新研制的开口锌凝固点容器中, 并通过微量元素Sn的添加实验对这些方法给予比较与研究.     

钙钛矿太阳能电池的研究进展

钙钛矿太阳能电池自2009年被提出以来取得了迅速的发展,其性能已超过了多晶硅太阳能电池。目前,钙钛矿太阳能电池的光电转换效率已达到20.8%。但是它面临着稳定性差的问题,这严重阻碍了其商业化进程。本文将总结近年来钙钛矿太阳能电池取得的部分研究进展和存在的问题,讨论提高钙钛矿太阳能电池光电转换效率和稳定性的途径,并对未来发展的方向进行了展望。     

技术合作与非合作选择的博弈分析

应用博弈理论建立了我国企业与跨国公司技术合作与非合作的选择模型;在此模型的基础上,分析了技术伙伴的选择标准以及技术合作中收益的分配比例,并对企业应该采取的对策提出了建议。     

染料敏化太阳能电池研究进展

介绍了染料敏化太阳能电池(DSSC)的基本结构、工作原理和影响其光电转换效率的关键材料,如阳极材料、染料、电解质、阴极材料;综述了各组成部分的研究现状和发展趋势.对于DSSC的研究,有序半导体氧化物薄膜的进一步优化,全吸收染料的合成以及高效准固态或固态电解质的应用,对提高电池的整体性能具有重要的意义.此外,还评述了近年来DSSC所面对的问题,展望了其工业化进程.     

柔性薄膜太阳电池的研究进展

综述了近年来柔性薄膜太阳电池的发展状况,结合柔性薄膜太阳电池的发展历史,分析了用作柔性衬底薄膜太阳电池的研究成果,探讨了各种器件结构的优缺点,并介绍了柔性衬底材料的选择及柔性太阳电池的研究进展.