Aside from the approximate analysis for <sup>17</sup>O by mass spectrometry in the early 1930s, precise measurement was begun by Nier in 1950, but he calibrated his mass spectrometer with enriched argon is...Aside from the approximate analysis for <sup>17</sup>O by mass spectrometry in the early 1930s, precise measurement was begun by Nier in 1950, but he calibrated his mass spectrometer with enriched argon isotopes for the inlet gas CO<sub>2</sub>. His展开更多
Ⅰ. INTRODUCTIONRecently Dr. H. E. Holden has published a comprehensive review on the isotopic abundance of boron in various terrestrial materials. Among the data of R<sub>11/10</sub>, the ratio of atomic ...Ⅰ. INTRODUCTIONRecently Dr. H. E. Holden has published a comprehensive review on the isotopic abundance of boron in various terrestrial materials. Among the data of R<sub>11/10</sub>, the ratio of atomic fractions of the two boron isotopes with mass of 11 and 10, only a few values are greater than 4.4, which is due to either the inaccuracy of measurement or the uncorrection for the mass discrimination in the mass spectrometric analysis.展开更多
As Dr. Barnes of the National Bureau of Standards, USA, wishes us to check the isotopic composition of the reference material NBS-123, sphalerite with known δ<sup>34</sup>S=17.32±0.12‰ vs CDT （tent...As Dr. Barnes of the National Bureau of Standards, USA, wishes us to check the isotopic composition of the reference material NBS-123, sphalerite with known δ<sup>34</sup>S=17.32±0.12‰ vs CDT （tentative）, Canyon Diablo triolite, an展开更多
With enriched antimony isotopes of 99.224 atom% ^(121)Sb and 99.528 atom% ^(123)Sb, twotracer solutions were prepared, whose antimony content was ascertained by the isotopicdilution analysis utilizing an accurately as...With enriched antimony isotopes of 99.224 atom% ^(121)Sb and 99.528 atom% ^(123)Sb, twotracer solutions were prepared, whose antimony content was ascertained by the isotopicdilution analysis utilizing an accurately assayed laboratory standard. Mass spectrometricmeasurements were made on a Finnigan MAT- 261 instrument to find the ratio of masses121 and 123. Five synthetic mixtures formed from the tracers served to determine thecorrection factor of mass discrimination. The isotopic abundances thus found for the anti-mony in the mineral stibnite together with the known nuclidic masses yield an accurateatomic weight of antimony as 121 .7575± 0 .0009.展开更多
Since Aston first applied the mass spectrometric method to the determination of the atomic weight of lithium, there have been accumulated twenty-seven such atomic values, among which two fall far from the mean atomic ...Since Aston first applied the mass spectrometric method to the determination of the atomic weight of lithium, there have been accumulated twenty-seven such atomic values, among which two fall far from the mean atomic weight, A_r (Li)=6.941, whereas all the others are within the uncertainty limit, U_r (Li)= ±0.002, which actually implies the natural variation of isotopic abundances.展开更多
Among the rare earth elements there are six with even atomic numbers starting from neodymium, which possess atomic weights with poor uncertainties of ±0.02%. The present study aims at making precise mass spectrom...Among the rare earth elements there are six with even atomic numbers starting from neodymium, which possess atomic weights with poor uncertainties of ±0.02%. The present study aims at making precise mass spectrometric measurement of the six isotopic abundance ratios of samarium, attempting to correct the measured ratio, R<sub>150/152</sub> of samarium, by the known true ratio, R<sub>151/153</sub> of europium, and normalizing the six ratios so as to yield new isotopic abundance values and the atomic weight of samarium, 150.3548±0.0009.展开更多
A review of the thirty-five mass spectrometric measurements of the atomic weight of carbon reveals that no strict bias calibration by enriched isotopes has ever been made. The best measurement performed by Craig owed ...A review of the thirty-five mass spectrometric measurements of the atomic weight of carbon reveals that no strict bias calibration by enriched isotopes has ever been made. The best measurement performed by Craig owed to Nier, and the absolute isotopic abundance ratio R<sub>13/12</sub> of carbon was determined by the calibration of argon isotopes that might have a different bias from carbon dioxide. With the enriched Ba<sup>12</sup>CO<sub>3</sub> prepared from the展开更多
文摘Aside from the approximate analysis for <sup>17</sup>O by mass spectrometry in the early 1930s, precise measurement was begun by Nier in 1950, but he calibrated his mass spectrometer with enriched argon isotopes for the inlet gas CO<sub>2</sub>. His
文摘Ⅰ. INTRODUCTIONRecently Dr. H. E. Holden has published a comprehensive review on the isotopic abundance of boron in various terrestrial materials. Among the data of R<sub>11/10</sub>, the ratio of atomic fractions of the two boron isotopes with mass of 11 and 10, only a few values are greater than 4.4, which is due to either the inaccuracy of measurement or the uncorrection for the mass discrimination in the mass spectrometric analysis.
基金Project supported by the National Natural Science Foundation of China, grant No. 2860341
文摘As Dr. Barnes of the National Bureau of Standards, USA, wishes us to check the isotopic composition of the reference material NBS-123, sphalerite with known δ<sup>34</sup>S=17.32±0.12‰ vs CDT （tentative）, Canyon Diablo triolite, an
基金Project supported by the National Natural Science Foundation of China.
文摘With enriched antimony isotopes of 99.224 atom% ^(121)Sb and 99.528 atom% ^(123)Sb, twotracer solutions were prepared, whose antimony content was ascertained by the isotopicdilution analysis utilizing an accurately assayed laboratory standard. Mass spectrometricmeasurements were made on a Finnigan MAT- 261 instrument to find the ratio of masses121 and 123. Five synthetic mixtures formed from the tracers served to determine thecorrection factor of mass discrimination. The isotopic abundances thus found for the anti-mony in the mineral stibnite together with the known nuclidic masses yield an accurateatomic weight of antimony as 121 .7575± 0 .0009.
基金Project supported by the Doctoral Fund State Commission of Education of China
文摘Since Aston first applied the mass spectrometric method to the determination of the atomic weight of lithium, there have been accumulated twenty-seven such atomic values, among which two fall far from the mean atomic weight, A_r (Li)=6.941, whereas all the others are within the uncertainty limit, U_r (Li)= ±0.002, which actually implies the natural variation of isotopic abundances.
基金Project supported by the National Natural Science Foundation of China
文摘Among the rare earth elements there are six with even atomic numbers starting from neodymium, which possess atomic weights with poor uncertainties of ±0.02%. The present study aims at making precise mass spectrometric measurement of the six isotopic abundance ratios of samarium, attempting to correct the measured ratio, R<sub>150/152</sub> of samarium, by the known true ratio, R<sub>151/153</sub> of europium, and normalizing the six ratios so as to yield new isotopic abundance values and the atomic weight of samarium, 150.3548±0.0009.
基金Project supported by the National Natural Science Foundation of China
文摘A review of the thirty-five mass spectrometric measurements of the atomic weight of carbon reveals that no strict bias calibration by enriched isotopes has ever been made. The best measurement performed by Craig owed to Nier, and the absolute isotopic abundance ratio R<sub>13/12</sub> of carbon was determined by the calibration of argon isotopes that might have a different bias from carbon dioxide. With the enriched Ba<sup>12</sup>CO<sub>3</sub> prepared from the
