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Research paper : A new density standard replaced from water (K. Fujii)−197 Synthesiology - English edition Vol.1 No.3 (2009) Discussion with Reviewers1 On manufacture of sample and importance of evaluationQuestion (Norimitsu Murayama)The success of this research was achieved by successful manufacture of high-quality silicon single-crystal sphere, along with development of various elemental technologies for absolute measurement of density. I think the synthesiological value of this paper will increase if you describe the manufacturing process and quality evaluation (purity, crystal imperfection, and etc.) of the silicon sphere.Answer (Kenichi Fujii)Since development of technology to polish silicon single-crystals into 1 kg sphere with high sphericity by CSIRO of Australia was major motivation for establishing new density standard to replace water, I added the manufacturing procedure and quality evaluation to the beginning of Section 3. Also, I added Reference [26] for details of polishing method. If the sphere was to be used only for density standard, it was not important to evaluate the purity or defect in the silicon spheres, and it would have been sufficient simply to guarantee the stability of the density by measurement. However, for determining the Avogadro constant, it was essential to correct the effect of impurities on density and lattice constant, to quantify the concentration of defects and atomic vacancies, and to accurately evaluate the average number of atoms in the unit cell. If the sphere was polished by conventional mechanical polishing, crystal defects occurred near the surface and it would be difficult to accurately determine the Avogadro constant. Therefore, CSIRO employed a mechano-chemical polishing method that incorporated chemical polishing at the final phase of polishing to minimize the subsurface damage in the crystal. By taking such polishing process, not only geometric perfection of the sphere, but also the crystallographic perfection can be guaranteed.2 Technical terminologiesQuestion (Norimitsu Murayama, Mitsuru Tanaka)I think readers from other fields will be able to understand better if you provide definitions and concepts for “relative combined standard uncertainty” and “the standard traceable to the definition of SI.”Answer (Kenichi Fujii)I added a Terminology section after Acknowledgements to explain relative combined standard uncertainty and traceability.3 Scientific demandQuestion (Mitsuru Tanaka)The description about demands in fundamental physical constants in 2.2 Scientific demand does not necessarily cover scientific demands, so I think you should give other examples. Perhaps you may discuss “verification of theory for the von Klitzing constant RK (or the fine structure constant ).”Answer (Kenichi Fujii)I added importance of verification for theories used in the Josephson and quantum Hall effects as scientific demand for measuring the Avogadro constant in Section 2.2.4 Scientific issues to be positioned as Type 1 Basic Research that composes Full ResearchQuestion (Mitsuru Tanaka)The study to determine the Avogadros constant by silicon single-crystals is described as starting point. Rather, it may be easier for people to understand, if volumetric technology of sphere is set as Type 1 Basic Research. Since scientific output is included as goal of Full Research, I think it makes it difficult to understand if you start from determination of the Avogadro constant from AuthorKenichi FujiiGraduated from the Department of Mechanical Engineering, Keio University in 1982. Completed graduate studies at the Department of Mechanical Engineering, Keio University in 1984. Doctor in Engineering. Joined the National Research Laboratory of Metrology in 1984. Worked on density standard and precise measurement of sound velocity of fluids. Joined the National Institute of Standards and Technology (NIST), USA as a Guest Scientist for 2 years from 1994, and worked on research for measurement of the Planck constant using the watt balance method. Chairman of the Working Group on Density (WGD), Comite Consultatif pour la Masse et les Grandeurs Apparentèes (CCM), Comité International des Poids et Mesures (CIPM). Member of Consultative Committee for Units (CCU). Member of the Task Group on Fundamental Constants, Committee on Data for Science and Technology (CODATA).(43)−vacuo for a determination of the avogadro constant, IEEE Trans. Instrum. Meas., 44, 542-545 (1995).K. Fujii, M. Tanaka, Y. Nezu, K. Nakayama, H. Fujimoto, P. De Bievre and S. Valkiers: Determination of the Avogadro constant by accurate measurement of the molar volume of a silicon crystal, Metrologia, 36, 455-464 (1999).N. Kuramoto, K. Fujii, Y. Azuma, S. Mizushima and Y. Toyoshima: Density determination of silicon spheres using an interferometer with optical frequency tuning, IEEE Trans. Instrum. Meas., 56, 476-480 (2007).K. Fujii: Precision density measurements of solid materials by hydrostatic weighing, Meas. Sci. Technol., 17, 2551-2559 (2006).Y. Sakamoto: Hydrometer and alcohol concentration measurement according to analysis method designated by National Tax Agency, Keisoku Hyojun to Keiryo Kanri (Measurement Standard and Measurement Management), 58(1), 10-14 (2008) (in Japanese).M. Obayashi: On JCSS calibration of vibrating tube densimeter and density standard liquid, Keisoku Hyojun to Keiryo Kanri (Measurement Standard and Measurement Management), 58(1), 15-19 (2008) (in Japanese).N. Kuramoto, K. Fujii and A. Waseda: Accurate density measurements of reference liquids by a magnetic suspension balance, Metrologia, 41, S84-S94 (2004).A. Waseda and K. Fujii: Density comparison measurements of silicon crystals by a pressure-of-flotation method at NMIJ, Metrologia, 41, S62-S67 (2004).A. Waseda, K. Fujii and N.Taketoshi: Density measurement of a thin-film by the pressure-of-flotation method, IEEE Trans. Instrum. Meas., 54 (2), 882-885 (2005).A. Waseda and K. Fujii: Density evaluation of silicon thermal-oxide layers on silicon crystals by the pressure-of-flotation method, IEEE Trans. Instrum. Meas., 56, 628-631 (2007).Y. Kano, Y. Kayukawa, K. Fujii and H. Sato: A new method for correcting a force transmission error due to magnetic effects in a magnetic levitation densimeter, Meas. Sci. Technol., 18, 659-666 (2007).Received original manuscript June 2, 2008Revisions received July 18, 2008Accepted July 18, 2008[30][31][32][33][34][35][36][37][38][39]

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