Chemical coal analysis can be supplemented by the determination of oxygen in high-and lowtemperature ash, in coal as received, and in dried coal at 105ยฐC. The rapid method utilizes fastneutron activation. The reaction 160(np)16N and counting of the 6.1 and 7.1 MeV gamma radiation of 7.3 s half-life
Rapid and simple spectrophotometric determination of oxygen stoichiometry in YBCO superconducting materials
โ Scribed by T. Nedeltcheva; L. Costadinova; P. Simeonova; V. Lovchinov
- Publisher
- Elsevier Science
- Year
- 1996
- Tongue
- English
- Weight
- 316 KB
- Volume
- 336
- Category
- Article
- ISSN
- 0003-2670
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โฆ Synopsis
A spectrophotometric method that does not require both measuring sample mass and calibration has been developed for determining oxygen stoichiometry in YBCO superconducting materials (bulk samples and films). The method allows the determination of the ratio between oxygen and copper molar quantities, as well as the calculation of the value of the ycoefficient in monophase YBa,Cu& superconducting materials. A monophase YBa&u,O, bulk sample is analyzed by the suggested method. The R.S.D. of the oxygen stoichiometric coefficient is 0.15%. The accuracy of the results is confirmed by a spectrophotometric method using calibration, as well as by iodometric titrations. The application of the method for determining oxygen stoichiometry in films is tested by analyzing smaller portions of the bulk sample following the procedure for film analysis. Two films of unproven homogeneity are analyzed, and the analytical results obtained are in good agreement with the film superconductivity.
๐ SIMILAR VOLUMES
The method of using absorbance in conjunction with hemoglobin (Hb) to monitor rapid changes in oxygen consumption in vitro was improved by using a non-linear calibration technique and multiwavelength spectroscopy. The O(2) dependence of Hb absorbance was effectively linearized using the current tech