紧跟SI步伐 顺应国际计量发展

为了更好地了解SI的这一发展趋势，国家质检总局特别邀请国际知名专家——国际计量局（BIPM）荣誉局长Terry Quinn博士和国际计量委员会单位制咨询委员会（CIPM／CCU）主席Ian Mills教授，分别作了题为《SI单位定义的实际复现以及国际计量委员会关于SI基本单位重新定义的建议》和《21世纪国际单位制（SI）的修订》的报告。     

四种测量玻尔兹曼常数的原级温度计研究综述

第26届国际计量大会批准了利用基本常量重新定义国际单位制（SI）。其中,温度单位“开尔文（K）”采用玻尔兹曼常量（k）重新定义。精确测量玻尔兹曼常量是重新定义开尔文和复现热力学温度的关键,本文详细介绍了用于测量玻尔兹曼常量的四种原级温度计：声学气体温度计、介电常量气体温度计、约翰逊噪声温度计、多普勒展宽温度计。阐述了四种原级温度计的工作原理、主要参数、实际应用情况,分析并探讨了它们对玻尔兹曼常量值修订起到的贡献。最后对原级测温方法未来发展方向进行总结与展望,为热力学温度的复现和传递提供研究支撑。     

国际计量局关于新SI常见问题解答

正2018年11月,第26届国际计量大会(CGPM)经国际计量局(BIPM)正式成员国表决,全票通过了关于国际单位制(SI)修订的"1号决议"。根据决议,新SI所有基本单位的定义都将建立在7个常数上,从而使SI以更高稳定性、复现方法多元性、全球通用性等优势,满足科学探索、技术发展等人类活动在长远未来的需求。根据决议,新SI将于2019年5月20日起正式生效。新SI到底改变了什么?为什么要做出这样的改变?     

四项国家计量基准采纳国际单位制新定义值

近日,市场监管总局发布2021年第5号公告,批准我国基于量子化效应建立的电学计量基准——直流电压基准装置、直流电压副基准装置、直流电压作证基准装置、直流电阻(量子化霍尔电阻)基准装置复现单位量值采纳国际单位制(SI)新定义值。2018年11月16日,第26届国际计量大会(CGPM)表决通过“修订国际单位制(SI)”的1号决议。     

国际计量体系及SI重新定义后的新格局

本文在对当前国际计量体系简要回顾的基础上,描述国际计量组织、区域计量组织和主要国家计量院在SI重新定义中所做的部分工作,探讨新SI下国际计量组织角色定位和职责任务的转变,以及国际计量格局可能的一些变化。     

国际单位制(SI) 迎来历史性变革

<正>2018年11月16日,第26届国际计量大会(CGPM)经包括中国在内的53个成员国表决,全票通过了关于"修订国际单位制(SI)"的1号决议。根据决议,SI基本单位中的4个,即千克、安培、开尔文和摩尔分别改由普朗克常数h、基本电荷常数e、玻尔兹曼常数A和阿伏伽德罗常数N_A定义。新定义于2019年5月20日起正式生效。     

漫谈国际单位制变革

2018年11月16日,第26届国际计量大会(CGPM)表决通过了关于"修订国际单位制(SI)"的1号决议。根据决议,国际单位制七个基本量的新定义将于2019年5月20日起正式生效。至此,国际测量体系有史以来首次全部建立在恒定不变的常数上。本文回顾计量发展的几个阶段,引入国际单位制的由来,分析其变革的原因,展望探讨国际单位制重新定义后可能带来的变化和影响,最后再简要介绍中国在国际单位制变革中的贡献与担当。     

发达国家计量管理的主要经验及对中国的启发

国际社会上公认不断建设和完善质量基础设施是解决全球质量问题的终极答案。计量在质量基础设施(NQI)体系框架内具有最重要的地位,是其他各质量要素的基础。尤其在2018年召开的国际计量大会上,对四个SI单位的定义重新修订,使得所有量值基于自然常数来定义,让量子基准取代了实物基准,让计量基础更加牢固,让架构在这之上的科学体系、测量体系、认证体系都获得了新的支撑。     

四项国家计量基准采纳国际单位制新定义值

正本刊讯近日,市场监管总局发布2021年第5号公告,批准我国基于量子化效应建立的电学计量基准——直流电压基准装置、直流电压副基准装置、直流电压作证基准装置、直流电阻(量子化霍尔电阻)基准装置复现单位量值采纳国际单位制(SI)新定义值。2018年11月16日,第26届国际计量大会(CGPM)表决通过"修订国际单位制(SI)"的1号决议,千克、安培、开尔文、摩尔等4个基本单位的定义与内涵发生重大变化。     

国家技术监督局关于在我国统一进行光辐射计量单位改值的通知

1979年第十六届国际计量大会重新定义了发光强度单位坎德拉(cd)。这在光度和辐射度计量的发展进程上具有重大意义。我国和一些工业先进国家根据新定义重新复现了发光强度单位坎德拉。并于1985年参加了由国际计量局组织的发光强度和总光通量标准的国际比对．     

Adapting the International System of Units to the twenty-first century

We review the proposal of the International Committee for Weights and Measures (Comité International des Poids et Mesures, CIPM), currently being considered by the General Conference on Weights and Measures (Conférences Générales des Poids et Mesures, CGPM), to revise the International System of Units (Le Système International d'Unitès, SI). The proposal includes new definitions for four of the seven base units of the SI, and a new form of words to present the definitions of all the units. The objective of the proposed changes is to adopt definitions referenced to constants of nature, taken in the widest sense, so that the definitions may be based on what are believed to be true invariants. In particular, whereas in the current SI the kilogram, ampere, kelvin and mole are linked to exact numerical values of the mass of the international prototype of the kilogram, the magnetic constant (permeability of vacuum), the triple-point temperature of water and the molar mass of carbon-12, respectively, in the new SI these units are linked to exact numerical values of the Planck constant, the elementary charge, the Boltzmann constant and the Avogadro constant, respectively. The new wording used expresses the definitions in a simple and unambiguous manner without the need for the distinction between base and derived units. The importance of relations among the fundamental constants to the definitions, and the importance of establishing a mise en pratique for the realization of each definition, are also discussed.     

The fundamental constants and the transition to new definitions of the SI units

Problems in fundamental metrology associated with variations in constants and the planned transition to new definitions of SI units based on fixed values of the fundamental physical constants are examined. It is pointed out that all the necessary conditions for such a transition have not yet been satisfied.     

新国际单位制——建立基本单位的里程碑

国际单位制是在米制基础上发展起来的,其基本单位是以国际单位原器为基准定义的.由于国际单位原器相对不稳定性,国际基本单位及其导出单位也存在一定的不确定度.因此,对国际基本单位进行了重新定义并给出了新定义的实现方法,建议在此基础上建立新国际单位制.新定义更多地采用了相对精确的基本常数,提高其相对标准精度.     

论新国际单位制(SI)的“秒制”特征及其未来发展

2019年5月20日起实行新的国际单位制,其主要变化在于7个基本单位用一个或多个定义的基本常数推导出,为基本单位确立了完美的标准定义。论述了新一轮国际单位制变革中基本单位千克、安培、开尔文和摩尔的新定义和特点;通过回溯国际单位制的发展历程,阐释了新国际单位制的“秒制”特征;最后分析了新国际单位制的问题和局限性,提出一种更加开放和包容多学科量值发展的新国际单位制体系的构想,并以此构建了新国际单位制未来发展的概念图。     

Possible definition of the unit of mass and fixed values of the fundamental physical constants

Ways of increasing the accuracy of the values of the Planck and Avogadro constants in experiments with Watt balances and crystalline silicon spheres are examined. These are needed for the new definitions of the kilogram and mole. The advantages and disadvantages of fixing the values of a number of fundamental physical constants when introducing definitions of the SI units are discussed, in particular a new definition of the unit of mass based on a fixed value of the Avogadro constant.     

Optimum choice of fundamental physical constants with fixed values for redefinition of SI units

The advantages and disadvantages of the procedure of fixing the values of fundamental physical constants (FPC) for redefining the basic SI units are examined. The case in which a fixed value of the Avogadro constant is used simultaneously for new definitions of the unit of mass and the unit of the amount of matter is discussed in detail. A criterion is proposed for choosing the optimum set of FPC with fixed values for redefining basic SI units. A set of FPC compatible with this criterion is considered.     

The Quantum Hall Effect and Von Klitzing Constant

Measurement Techniques - The paper addresses a current issue in the area of electrical measurements arising from the new definitions of the SI base units adopted at the 26th General Conference on...     

A new quantification algorithm for the GO methodology

This paper provides a new quantification algorithm in the GO methodology, which includes three parts: (1) A signal state cumulative probability is introduced and defined based on the definitions of the signal states in the GO method. (2) The quantitative formulas of signal state cumulative probabilities have been derived, so it is unnecessary to calculate the joint probability of the complex combination of states. (3) The calculation process and the transfer rules about the shared signal have been presented, therefore, the new algorithm permits the direct calculation of all signal state cumulative probability. The new algorithm is very easy for programming. It is an improved algorithm in the GO methodology instead of the joint probability algorithm. The result of an example shows that the algorithm is practical and meaningful for development and application of the GO methodology and useful in practice.     

The Current SI Seen From the Perspective of the Proposed New SI

A revised International System of Units (SI) proposed by the International Committee for Weights and Measures is under consideration by the General Conference on Weights and Measures for eventual adoption. Widely recognized as a significant advance for both metrology and science, it is defined via statements that explicitly fix the numerical values of a selected set of seven reference constants when the values of these constants are expressed in certain specified units. At first sight this approach to defining a system of units appears to be quite different from that used to define the current SI. However, by showing how the definitions of the seven base units of the current SI also fix the numerical values of a set of seven reference constants (broadly interpreted) when the values of these constants are expressed in their coherent SI units, and how the definition of the current SI can be recast into the same form as that of the revised SI under consideration, we show that the revision is not as radical a departure from the current SI as it might initially seem.     

Preparative Steps Towards the New Definition of the Kelvin in Terms of the Boltzmann Constant

The International Committee for Weights and Measures (CIPM) approved, in its Recommendation 1 of 2005, preparative steps towards new definitions of the kilogram, the ampere, the kelvin, and the mole in terms of fundamental constants. Within the Consultative Committee for Thermometry (CCT), a task group (TG-SI) has been formed to consider the implications of changing the definitions of the above-mentioned base units of the SI, with particular emphasis on the kelvin and the impact of the changes on metrology in thermometry. The TG-SI has presented the results of its deliberations to the CCT and to the Consultative Committee for Units, CCU, and worked with them to prepare a report to the CIPM. This contribution, authored by the members of TG-SI, solicits input from the wider scientific and technical community on this important matter at the TEMPMEKO 2007 conference. For this purpose, the main details of the report to the CIPM are presented. The unit of temperature T, the kelvin, can be defined in terms of the SI unit of energy, the joule, by fixing the value of the Boltzmann constant k, which is simply the proportionality constant between temperature and thermal energy kT. Currently, several experiments are underway to determine k. The TG-SI is monitoring closely the results of all experiments relevant to the possible new definition of the kelvin, and has identified conditions to be met before proceeding with the proposed redefinition. The TG-SI considers that these conditions will be fulfilled before the 24th General Conference on Weights and Measures in October 2011. Therefore, the TG-SI is recommending a redefinition of the kelvin by fixing the value of the Boltzmann constant. A new definition of the kelvin in terms of the Boltzmann constant does not require the replacement of ITS-90 with an improved temperature scale nor does it prevent such a replacement. H. Ugur is the President, Consultative Committee for Thermometry (CCT).