The National Institute of Metrology (NIM, China) proposed a joule balance method to measure the Planck constant in 2006, and built the first prototype NIM-1 to verify its principle with a relative uncertainty of 8.9 × 10 -6 by 2013. Since 2013, a new joule balance NIM-2 has been designed, with a series of improvements to reduce the measurement uncertainty. By April 2017, NIM-2 has been constructed and can be employed to measure the Planck constant in vacuum. A first measurement on NIM-2 yields a determination of the Planck constant is 6.626 069 2(16) × 10 -34 Js with a relative uncertainty of 2.4 × 10 -7 . The determination differs in relative terms by −1.27 × 10 -7 from the CODATA 2014 value. Further improvement of NIM-2 is still in progress towards 10 -8 level uncertainty in the future.

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Abstract-A frequency dependent model of sheet resistance of transparent conductive mesh coatings is proposed based on transmission line theory and vilified by experiments. And the effect on shielding effectiveness of frequency dependent sheet resistance is analyzed. Simulation results of shielding effectiveness are compared with the experimental data of a mesh-coated window sample with equivalent parameters fabricated and measured by Exotic Electro-Optics. The agreement between experiment and simulated proves the validity of the proposed sheet resistance model. So it can be therefore concluded that the frequency dependent model can be used to reasonably evaluate sheet resistance and shielding effectiveness of transparent conductive mesh coated windows.

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