Estimating seismic attenuation (Q) by an analytical signal method

2005 ◽  
Author(s):  
Arnim B. Haase ◽  
Robert R. Stewart
2021 ◽  
Vol 80 (17) ◽  
Author(s):  
Khalid S. Essa ◽  
Eid R. Abo-Ezz ◽  
Yves Géraud

Author(s):  
Nguyen Le Minh ◽  
Satoru Tanaka ◽  
Yasushi Ishihara ◽  
Nguyen Tien Hung ◽  
Ha Vinh Long ◽  
...  
Keyword(s):  

2018 ◽  
Vol 84 (11) ◽  
pp. 9-14
Author(s):  
E. S. Koshel ◽  
V. B. Baranovskaya ◽  
M. S. Doronina

The analytical capabilities of arc atomic emission determination of As, Bi, Sb, Cu, Te in rare earth metals (REM) and their oxides after preparatory group concentration using S,N-containing heterochain polymer sorbent are studied on a high-resolution spectrometer “Grand- Extra” (“WMC-Optoelectron-ics” company, Russia). Sorption kinetics and dependence of the degree of the impurity extraction on the solution acidity are analyzed to specify conditions of sorption concentration. To optimize the procedure of arc atomic emission determination of As, Bi, Sb, Cu, and Te various schemes of their sorption preconcentration and subsequent processing of the resulted concentrate with the addition of a collector at different stages of the sorption process have been considered. Graphite powder is used as a collector in analysis of rare earth oxides due to universality and relative simplicity of the emission spectrum. Conditions of analysis and parameters of the spectrometer that affect the analytical signal (mass and composition of the sample, shape and size of the electrodes, current intensity and generator operation mode, interelectrode spacing, wavelengths of the analytical lines) are chosen. The evaporation curves of the determinable impurities were studied and the exposure time of As, Bi, Sb, Cu, and Te in the resulted sorption concentrate was determined. Correctness of the obtained results was evaluated using standard samples of the composition and in comparisons between methods. The results of the study are used to develop a method of arc chemical-atomic emission analysis of yttrium, gadolinium, neodymium, europium, scandium and their oxides in a concentration range of n x (10-2 - 10-5) wt.%.


2020 ◽  
Vol 16 (7) ◽  
pp. 872-879
Author(s):  
Samin Hamidi

Background: Abuse of drugs is associated with several medical, forensic, toxicology and social challenges. “Drugs of abuse” testing is therefore an important issue. Objective: We propose a simple CE-based method for the quantification of amphetamine, codeine and morphine after direct injection of Exhaled Breath Condensate (EBC) by the aid of simple stacking mode and an off-line pre-concentration method. Methods: Using graphene oxide adsorbents, amphetamine, codeine and morphine were extracted from EBC in order to eliminate the proteins and other interferences. In addition to off-line method, an online stacking mode was applied to improve the analytical signal obtained from the instrument. Results: The validation parameters were experimented on the developed method based on the FDA guideline over concentration ranges of 12.5-100, 30-500 and 10-1250 ng/mL associated with amphetamine, codeine and morphine, respectively. Small volumes (around 100 μL) of EBC were collected using a lab-made setup and successfully analyzed using the proposed method where precisions and accuracies (within day and between days) were in accordance with the guideline (recommended less than 15 % for biological samples). The recovery tests were used to evaluate the matrix effect and data (94 to 105 %) showed that the proposed method can be applied in different EBC matrix samplings of subjects. Conclusion: The proposed method is superior for simultaneous determination of amphetamine, codeine and morphine over chromatographic analyses because it is fast and consumes fewer chemicals, with no derivatization step.


1988 ◽  
Vol 53 (12) ◽  
pp. 3021-3028 ◽  
Author(s):  
Karel Eckschlager ◽  
Jiří Fusek

It is shown how the information content expressed in terms of the extended divergence measure I(r; p, p0) depends on the amount of the component to be determined when homoscedastic and heteroscedastic dependences of the analytical signal on the amount of the analyte are distinguished. The importance of the accuracy is pointed out, with which the amount of the analyte is known in a reference material employed for testing a particular analytical method. Rules are set, the maintaining of which is aimed at avoiding the origin of null information content of analytical results.


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