• 제목/요약/키워드: Precision metrology

검색결과 116건 처리시간 0.029초

Development of analytical method for the isotope purity of pure D2 gas using high-precision magnetic sector mass spectrometer

  • Chang, Jinwoo;Lee, Jin Bok;Kim, Jin Seog;Lee, Jin-Hong;Hong, Kiryong
    • 분석과학
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    • 제35권5호
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    • pp.205-211
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    • 2022

  • Deuterium (D) is an isotope with one more neutron number than hydrogen (H). Heavy elements rarely change their chemical properties with little effect even if the number of neutrons increases, but low-mass elements change their vibration energy, diffusion rate, and reaction rate because the effect cannot be ignored, which is called an isotope effect. Recently, in the semiconductor and display industries, there is a trend to replace hydrogen gas (H2) with deuterium gas (D2) in order to improve process stability and product quality by using the isotope effect. In addition, as the demand for D2 in industries increases, domestic gas producers are making efforts to produce and supply D2 on their own. In the case of high purity D2, most of them are produced by electrolysis of heavy water (D2O), and among D2, hydrogen deuteride (HD) molecules are present as isotope impurities. Therefore, in order to maximize the isotope effect of hydrogen in the electronic industry, HD, which is an isotope impurity of D2 used in the process, should be small amount. To this end, purity analysis of D2 for industrial processing is essential. In this study, HD quantitative analysis of D2 for high purity D2 purity analysis was established and hydrogen isotope RM (Reference material) was developed. Since hydrogen isotopes are difficult to analyze with general gas analysis instrument, they were analyzed using a high-precision mass spectrometer (Gas/MS, Finnigan MAT271). High purity HD gas was injected into Gas/MS, sensitivity was determined by a signal according to pressure, and HD concentrations in two bottles of D2 were quantified using the corresponding sensitivity. The amount fraction of HD in each D2 was (4518 ± 275) μmol/mol, (2282 ± 144) μmol/mol. D2, which quantifies HD amount using the developed quantitative analysis method, will be manufactured with hydrogen isotope RM and distributed for quality management and maintenance of electronic industries and gas producers in the future.

  • https://doi.org/10.5806/AST.2022.35.5.205 인용 PDF KSCI HTML

Measurement of Cortisol in Human Serum by Isotope Dilution Liquid Chromatography/Mass Spectrometry and a Comparison through a Proficiency Testing

  • Lee, Hwa-Shim;Shin, Hye-Sun;Park, Sang-Ryoul;Park, Chang-Joon
    • Bulletin of the Korean Chemical Society
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    • 제31권5호
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    • pp.1149-1154
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    • 2010

  • Liquid chromatography/mass spectrometry using isotope dilution method has been established as a primary method for the measurement of cortisol in human serum. Verification of this method was accomplished by the participation in Consultative Committee for Amount of Substance-Metrology in Chemistry (CCQM) pilot study. Two levels of cortisol certified reference materials were prepared and certified by the established method. They were used as sample materials for the proficiency testing. The expanded uncertainty in the measurement of cortisol in human serum was approximately 1.2% at 95% confidence level. The results of the proficiency testing showed a good precision among the participants, but some bias to the certified values. This means that commercial field laboratories should keep traceability chain to SI unit through available reference measurement procedures and/or available reference materials.

  • https://doi.org/10.5012/bkcs.2010.31.5.1149 인용 PDF KSCI

Effects of observation parameters on time transfer using GPS

  • Lee, Seung-Woo;Lee, Chang-Bok;Yang, Sung-Hoon;Lee, Young-Kyu;Han, Ji-Ae
    • 한국항해항만학회:학술대회논문집
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    • 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.2
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    • pp.113-116
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    • 2006

  • In order to fully utilize the inherent precision that GPS observables could offer, accurate estimation of dynamic and measurement parameters is vital. Among these parameters some are indispensable in virtually every form of GPS processing, while some are limitedly relevant to a particular application. In the context of time transfer by GPS, the transmission-related errors such as ionospheric and tropospheric delays, and the integer ambiguity of the carrier phase observables belong to the former, the atomic clock parameters and data batch-related parameters to the latter. Obviously the atomic clock parameters are of prime importance in GPS time transfer. In this study some of important parameters in conducting time transfer experiments by use of GPS were characterized and their effects on time transfer performance were investigated in detail

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