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1.
A scheme for INAA of pottery is proposed. The combination of 3 irradiations-epithermal and pile (short and long time) and 6 measurements (2 times after each irradiation) enables the determination of Al, As, Au, Ba, Br, Ce, Co, Cr, Cs, Dy, Eu, Fe, Hf, K, La, Lu, Mg, Mn, Na, Nd, Rb, Sb, Sc, Si, Sm, Ta, Tb, Th, Ti, U, V and Yb. The accuracy and precision of the method is evaluated by analysis of standard reference materials (USGS-BCR-1, USGS-W-1, ZGI-TB). The applicability of the method is demonstrated by analysis of 15 sgraffito ceramics from XV–XVIII cc. from Tzarevetz, Veliko Tirnovo (Bulgaria). The results from the clustering of the analytical data are presented and discussed. 相似文献
2.
An ion-exchange procedure is proposed for determination of Pt and Pd in environmental samples, using a Dowex 1-X10 anion-exchange resin. Pt and Pd were separated from the matrix elements in the sample by selective retention on the column as anionic chloro complexes and subsequent elution by circulated thiourea at 60 °C. The eluent, containing Pt and Pd was analyzed by inductively coupled plasma (ICP) atomic emission spectrometry (AES). Average recoveries of 98% and detection limit of 15 ng/g for both metals were achieved. Analysis of Pt and Pd concentrations in road dust, sampled from several sites in Germany was performed. The comparison of the obtained data with the concentrations of Pt and Pd in the same samples, determined by ICP-MS showed a very good agreement. 相似文献
3.
A sequential extraction procedure was used to study the changes in the physicochemical forms of americium (Am), thorium (Th), and uranium (U) in laboratory-contaminated Chernozem soil as a result of sharp variations of the environmental temperature and soil moisture. The influence of freezing and soil drought on the radio-ecological hazard was evaluated three months after radioactive contamination with aqueous solutions of 241Am, 234Th, and U. The subsequent changes in the physicochemical forms of the actinides, caused by sharp increases in the environmental temperature and soil moisture, were examined for one month. The data showed that continuous freezing increased the potentially mobile forms of Am and Th but had the opposite effect on U. Prolonged soil drought did not influence the fractionation of Am and Th but led to the redistribution of U between the carbonates and organic matter and caused its immobilisation. The sharp increase in the temperature of the frozen soil caused the immobilisation of Am and Th and increased the potential mobility of U. The warming and enhanced humidity of the dry soil led to the immobilisation of Am and redistribution of U between the soil phases. 相似文献
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Valentina Ljubomirova Rumyana Djingova Johannes T. van Elteren Marjan Veber Tomasz Kowalkowski Boguslaw Buszewski 《International journal of environmental analytical chemistry》2013,93(7):499-512
A sequential extraction procedure (three-step), proposed by the Standards, Measurements and Testing Programme (formerly BCR) of the European Union, was applied to street dust and spiked soil samples for the determination of PGEs. Analyses were carried out using inductively coupled plasma-mass spectrometry (ICP-MS). The results indicate that up to 5% from Pt, 70% from Pd and 14% from Rh are in mobile forms in street dust. The results for the soil samples spiked with crushed catalytic converter are significantly lower indicating that PGEs are oxidised more efficiently in natural conditions. Additionally Pt and Pd bound to humic acids were investigated. 相似文献
6.
Rumyana St. Velichkova Rayna Al. Tsevi 《Journal of polymer science. Part A, Polymer chemistry》1986,24(12):3399-3405
The polymerization of styrene oxide by nitronium tetrafluoroborate in nitromethane and methylene chloride at 5, 20, and 50°C is investigated. GPC analyses of the products combined with isocyanate method show that both cyclic and linear oligomers are formed. In CH3NO2 the cyclic dimer and trimer are 2-benzyl-4-phenyl-1,3-dioxolane and 1,3,5-tribenzyl-trioxane, respectively. In CH2Cl2 2,5-diphenyldioxane is isolated. In nitromethane, mainly isomerized structures with acetal linkage are produced, while in methylene chloride isomerization does not proceed. By NMR and IR spectra the presence of C?O and OH end groups in the linear oligomers is shown. There are indications that oligomers are formed both directly from the monomer and by degradation of the polymer. 相似文献
7.
I. Kuleff R. Djingova A. Alexandrova M. Iovtschev 《Isotopes in environmental and health studies》2013,49(2):90-92
Ion exchange chromatography of boric acid was carried out using an anion exchange resin in fluoride and chloride forms in order to investigate the temperature dependence of separation factor (S) for boron isotopes. The results are summarized as follows: For the fluoride form resin system, S? 1 = 1348/T2 ? 0.0051 (between 5 °C and 35 °C) and for the chloride form resin system, S? 1 = 645/T2 ? 0.0053 (between 5 °C and 50 °C) where T is the temperature in units of K. 相似文献
8.
Rumyana Djingova Veronika Mihaylova Valentina Lyubomirova Dimiter L. Tsalev 《应用光谱学评论》2013,48(5):384-424
Abstract: The study of the ionome (ionomics) is defined as quantitative and simultaneous measurement of the element composition of living organisms and changes in this composition in response to physiological stimuli, development stage, and genetic modifications (Salt et al., Ann. Rev. Plant Biol., Vol. 59, 2008). The necessity of understanding the regulation processes of elements in the organisms demands determination of many elements in the organism, tissue, and cell (Baxter, Plant Biol., Vol. 12, 2009). A prospect for ionomics is environmental pollution where great variety of conditions and pollutants exist resulting in concentration and interelemental changes in the plant ionome. The capabilities of and problems with several multielement analytical techniques, including instrumental neutron activation analysis (INAA), X-ray fluorescence, inductively coupled plasma–atomic emission spectrometry (ICP-AES), inductively coupled plasma–mass spectrometry (ICP-MS), and atomic absorption spectrometry (AAS), which are adequate and most promising in ionomic and environmental studies of plants, are reviewed. References are confined mainly to the last 10–15 years. Information about concentrations, roles, binding forms, and pollution sources of the elements and comparison between methods with respect to limits of detection, determined elements, interferences, and economic considerations are tabulated. Some combinations of instrumental techniques supplementing each other are highly valued, namely, ICP-MS and ICP-AES and INAA and AAS or ICP-AES. 相似文献
9.
R. Djingova Ju. Ivanova I. Kuleff 《Journal of Radioanalytical and Nuclear Chemistry》1998,237(1-2):25-34
The usefulness of INAA, radionuclide ED-XRF, ICP-AES and AAS are comparatively evaluated for the determination of nutrients,
essential and trace elements in various plant matrices. The comparison is performed by analysis of the following reference
materials: NIST-SRM-1573, NIST-SRM-1575, NIES-1, NIES-3, NIES-6, IAEA-V-10 and Bowen's kale. The detection limits, accuracy
and precision of the methods are discussed and a combination of INAA and GFAAS is recommended for analysis of plants for monitoring
purposes. 相似文献
10.
L. Popov I. Kuleff R. Djingova 《Journal of Radioanalytical and Nuclear Chemistry》2006,269(1):203-207
Summary A procedure for the radiochemical separation and radiochemical purification of radiocesium (134Cs and 137Cs) in bulk environmental water samples is proposed. Radiocesium was removed from the water by cation-exchange with copper
ferro(II)cyanide and was purified by precipitation with sodium tetraphenylborate. The influence of the concentration of potassium
in the water sample on the chemical yield was investigated. The validation of the proposed method was carried out by analyzing
reference materials. The application of the method was demonstrated with the determination of the concentration of radiocesium
in water samples from rivers around NPP “Kozloduy”, Bulgaria, Danube and Ogosta. 相似文献