Quality Alchemist (品質煉金術師): Metrology Symposium 2019 (The New SI for a Smarter World)

2019年1月11日星期五

Metrology Symposium 2019 (The New SI for a Smarter World)

The Government Laboratory (GL), Hong Kong Council for Testing and Certification (HKCTC), Open University of Hong Kong (OUHK) and Standards and Calibration Laboratory of Innovation and Technology Commission (SCL) jointly organized the Metrology Symposium 2019 on 11^th Jan 2019. The theme is “The New SI for a Smarter World”. Hong Kong Society for Quality (HKSQ) was one of supporting organizations. On May 20, 2019, the implementation of the revised International System of Units (SI) would start. Four of the seven SI base units namely kilogram, ampere, kelvin and mole would be redefined based on the fundamental constants, which remove the current limitations imposed by the use of artefact standards. Before the seminar, I met Ms. Brenda Lam (SCL) and we took a photo for memory.

In the entry of venue, silicon sphere was set for the new definition of mass use.

I took a photo with silicon sphere for memory.

I also met Mr Nick Leung (HKAS) and we seat together.

In the beginning, Prof. Reggie Kwan Ching Ping (Vice President, OUHK) gave welcoming address. He briefed that OUHK had 30 years with more than 9000 students. Testing and Certification was one of key program in OUHK.

Mr. WW Wong (Assistant Commissioner, Innovation and Technology Commission) gave opening remarks. He mentioned one of tasks was metrology through SCL to assurance the accuracy and reliability that traceable to SI units. He also stated that the poster designed by SCL was selected as the poster of the World Metrology Day 2019 and the design ideas were based on modern world becoming smarter with many smart technologies such as Artificial Intelligence (AI), big data, robotics, virtual reality (VR), 5G and autonomous vehicles, etc.

The all speakers took a group photo.

The first speaker was Dr. Della Sin (Government Chemist, Government Laboratory) and her topic entitled “The new SI and its implications”. Firstly, Dr. Sin briefed Measurement and Metrology basic concept and history that the Metre Convention signed in Paris since 1875.

Then she mentioned the BIPM’s member states voted on 16 Nov 2018 at the 26^th meeting of the General Conference on Weights and Measures (CGPM) to revise the Four SI units in terms of Physical Constants. The 9^th edition of SI Brochure would be published by BIPM at https://www.bipm.org/en/measurement-units/ . And the she briefed implications of the revision.

Finally, Dr. Sin summarized that the new definitions of SI would come into force on 20 May 2019. It simplified the definition from material artefact to the physical constants. The revision of the SI would ensure that the SI continued to meet the needs of science, technology, and commerce in the 21^st century.

The second speaker was Ir. Aaron YK Yan (Head of Laboratory, Standards and Calibration Laboratory) and his topic named “The New SI for a Smarter World – The Story of the SI”. “Measurement is not a new things and it happened in Ancient Times” Ir. Yan said.

Then Ir. Yan introduced different International Metrology Infrastructure included General Conference on Weights and Measures (CGPM), International Committee for Weights and Measures (CIPM), International Bureau of Weights and Measures (BIPM), and Consultative Committee (CC). The International System of Units started since 1960 which was scientifically based coherent units. Then he introduced the revised SI 7 Physical Constants in following diagram.

Finally, he said the future direction would be redefinition of second based on optical clock(s) to achieve accuracy in 10^-18. He used a France sentence “a tous les temps, a tous les peuples” (At all time, for all people) to conclude his presentation.

Dr.-Ing. Prof. HC Frank Hartig (Head of Division Mechanics and Acoustic, PTB, Germany) was the third speaker and his presentation title was “The new kilogram now approachable for extraterrestrials and nonhumans”. Firstly, Prof. Frank Hartig briefed the SI based on artefacts and then introduced SI based on defining constants.

The future kilogram (kg) would be defined by taking the fixed numerical value of the Planck constant h to be 6.626 070 15 x 10^-34 when expressed in the units Js (kg m² s^-1). Prof. Hartig then demonstrated the silicon sphere to us.

The new definition of mass equation was demonstrated and explained. Finally, he concluded the new kilogram using a modified France sentence “a tous les temps, a tous les espece intelligente” (At all times, to all intelligent species).

During the tea break, there were some research posters demonstration. Poster for redefinition of the kilogram showed two primary methods and they were Kibble Balance and Avogadro Sphere (Si Sphere).

Another poster showed the time frame for revision of SI. It was simple and easy to understand the whole story.

The fourth speaker was Dr. WF Wong (Chemist, Government Laboratory) and her presentation named “Mole: Definition and Facts, Now and in the Future”. Firstly, she briefed the history of the Mole. The current definition is the amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kilogram of carbon 12. But new definition of the mole would no longer be related to the carbon 12.

Dr. Wong explained the current and new definition of the Mole through the following table. That uncertainty is almost zero.

After that she briefed the metrological traceability which stated in ISO/IEC 17025:2017 and ISO 17034:2016. The Metrological Traceability Network was showed in the following diagram. Lastly, she concluded that one mole contained exactly 6.02214076 x 10²³ elementary entities. Avogadro constant is fixed with no uncertainty. Moreover, revised definition of the mole would not require any change to common practice.

The fifth speaker was Ir. Raymond Leung (Electrical and Mechanical Engineer, SCL) and his topic entitled “The metric system is of so much interest”. Firstly, he briefed the metric system employed in Hong Kong many years ago.

Then he mentioned the seven base units to be revised as follows.

Finally, Ir. Leung concluded that the revised definitions used “the rule of nature to create the rules measurement”. So that it would provide long-term stability and ensured that SI continued to meet the needs of science, technology, and commerce in the 21^st century.

The sixth speaker was Ir. Dr. Steven Yang (Electronics Engineer, Standards and Calibration Laboratory) and his presentation topic named “Small Changes in Electrical Units, a Big Step Forward in Electrical and Medical Metrology”. Firstly, Dr. Yang briefed the current definition of unit of electric current (ampere). Current practical realization of ampere was used either Josephson effect or Quantum Hall effect.

Then Dr. Yang stated the revised definition of electric current (ampere) that defined by taking the fixed numerical value of the elementary charge e to be 1.602176634x10^-19 when expressed in the unit C. (Current = Flow of charge).

Finally, Dr. Yang mentioned several medical application would be benefit under new definition for electrical testing.

Ir. Dr. Terry Lai (Electronics Engineer, SCL) was the last speaker and his topic entitled “Optical Clocks and the Future of the Second”. Firstly, Dr. Lai briefed one second time interval of the mechanical clock and digital clock. In which crystal oscillator employed in digital clock.

Then Dr. Lai introduced Atomic Clocks family included microwave frequency standard and optical frequency standard. Optical clocks had potential to realize the second at much lower uncertainty than caesium clocks in the future.

Q&A Session

Some interesting questions were discussed. For instance. Dr. Terry Lai answered that the bill of electricity would be increased HKD7000 for whole HK electricity consumption per year under new unit definition. For chemistry, Dr. WF Wong said it was no effect on chemical testing even though down to ppb level.