共查询到20条相似文献,搜索用时 10 毫秒
1.
A. Komosa 《Journal of Radioanalytical and Nuclear Chemistry》1999,240(1):19-24
The distribution of Pu isotopes in three profiles of forest soil in Lublin region was determined. The retention half-time
and migration velocity of239,240Pu originated from global and Chernobyl fallouts was calculated. The average rate of migration of the global fallout plutonium
was 0.4 cm/year and that of the Chernobyl one 0.7 cm/year. Good correlation between Pu concentration and organic matter contents
was found only in the case of podzolic soil profile. In two profiles a good negative correlation between Pu activity and exchangeable
pH of the soil layer was determined. 相似文献
2.
Investigation of adsorption and vertical migration of137Cs in three kinds of soil at Lublin vicinity
S. Chibowski J. Zygmunt Z. Klimowicz 《Journal of Radioanalytical and Nuclear Chemistry》1999,242(2):287-295
The results of field, column and laboratory studies carried out on three types of mineral soils are encloses presented. Based
on the field tests, average migration rates of137Cs were calculated. The highest rate was found for the brown soil (FAO/UNESCO—Cambisol). Cesium migrated with the lowest rate
in the podzol soil (FAO/UNESCO—Cambic Podzol). The column experiments confirmed the above observation. In laboratory tests
the adsorption and desorption isotherms of Cs were determined on samples taken from 0–2 cm layers of each soil profile. It
was found from the calculated partition coefficients that Cs is always irreversibly bonded to some extent, but it appears
to be completely and irreversibly immobilized on the podzol soil. The permanent retention of cesium in the podzol soil was
also confirmed by microcalorimetric studies. The desorption energy was negligibly small and amounted to −0.21 mJ/g. In the
brown soil, containing prevailing amounts of loamy minerals, the desorption energy was found to be 106.89 mJ/g. The investigations
are supplemented by the sorption kinetics measurements. These indicate that the adsorption equilibrium is reached after a
dozen, up to twenty or so minutes. 相似文献
3.
J. Zygmunt S. Chibowski Z. Klimowicz 《Journal of Radioanalytical and Nuclear Chemistry》1998,231(1-2):57-62
The vertical distribution of137Cs is shown for two types of soil: silly loamy “supposed” soil and silly lessive one, slightly eroded, occuring in the vicinity
of Lublin (Eastern Poland). Based on the distribution data the vertical migration rates of137Cs are calculated for both soils. These rates are found to be 0.045 and 0.3 cm/year respectively. The percent contribution
of137Cs originating from the damaged reactor in Chernobyl is also calculated. The kinetics of cesium adsorption and its adsorption
isotherms on minerals separated from the tested soils are also studied. The sorption of Cs on soil minerals markedly affects
the migration rate of137Cs in soil. The experimental results indicate that, among the extracted mineral fractions, the largest adsorption takes place
on marls from the silly loamy soil. This work is supplemented by results of a physicochemical analysis of the studied soils. 相似文献
4.
Radon concentration in basements of old buildings in the oldest towns of Lublin region (Zamo, Chelm and Sandomierz) was determined. Two techniques were applied: passive (Pico-rad) and alpha-spectrometry for radon progeny concentration measurement (SILENA). It was found that only 7% of results exceeded a dose limit of 400 Bq·m-3, established for old buildings. Radon concentration levels ranged from 0.2 to 5150 Bq·m-3. Distribution of the results satisfied a log-normal relationship. Applying these two methods at the same time, the radioactive equilibrium factor of radon and its progeny was determined. In the underground ways, open for visitors, no higher radon concentration was observed. 相似文献
5.
J. Solecki M. Reszka S. Chibowski 《Journal of Radioanalytical and Nuclear Chemistry》2003,257(2):261-265
Radioactivity of 90Sr and 137Cs in several species of herbs collected at Fajsawice and Góra Puawska located in Lublin (Poland) region was examined. Depending on the type of herb the radioactivity of strontium ranged from 0.004 to 1.808 Bq/kg dry weight whereas that from cesium varied from 0.053 to 9.853 Bq/kg. Calculated transfer factors of the radioisotopes in the plants studied revealed much stronger accumulation of strontium than cesium. Concentration of calcium and potassium in these plants has no influence on the concentration of measured radioisotopes. 相似文献
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The first plutonium(III) borate, Pu(2)[B(12)O(18)(OH)(4)Br(2)(H(2)O)(3)]·0.5H(2)O, has been prepared by reacting plutonium(III) with molten boric acid under strictly anaerobic conditions. This compound contains a three-dimensional polyborate network with triangular holes that house the plutonium(III) sites. The plutonium sites in this compound are 9- and 10-coordinate and display atypical geometries. 相似文献
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10.
A. V. Stepanov T. P. Makarova A. M. Fridkin 《Journal of Radioanalytical and Nuclear Chemistry》1979,51(2):385-391
The behaviour of the complex ion formed by quadrivalent plutonium with 1,2-diaminecyclohexanetetraacetic acid (DCTA) in reductive
media is studied. 相似文献
11.
R. M. Piasentin M. J. A. Armelin O. Primavesi P. E. Cruvinel 《Journal of Radioanalytical and Nuclear Chemistry》1998,238(1-2):7-12
Instrumental neutron activation analysis (INAA), followed by gamma-ray spectrometry, was used to determine the concentration
of K, Ca, Mg, Na, Zn, Fe, Mn, Mo, Co, Cr, La, Eu and Th in six species of legumes and three species of grasses. Each species
of forage was cultivated on two differet oxisols, that is, a red yellow Latossol and a dark red Latossol, with the aim of
comparing the influence of the soils in the mineral extraction. Besides, on each kind of soil, two different limestone concentrations
were used in order to verify how the soil pH correction could influence the elemental absorption in each species, and at the
same time; to search for an optimum value of limestone concentration for each soil. 相似文献
12.
A. G. Rykov N. N. Andreychuk V. Ya. Vasilev V. A. Ermakov 《Journal of Radioanalytical and Nuclear Chemistry》1979,51(2):363-376
Plutonium(IV) oxidation has been studied in 1 to 20 mol/1 HNO3 under 1 to 14 W/1 internal alpha-irradiation and at plutonium concentrations from 2 to 100 mmol/1. Curium isotopes have been
used as the basic alpha-irradiation sources. It has been established that in the systems investigated both oxidation of plutonium(IV)
and reduction of plutonium(VI) take place, resulting with time in reaching the equilibrium between plutonium(IV) and plutonium(VI).
The presence of plutonium(IV) enhances the reduction of plutonium(VI). The rate constants for plutonium(IV) oxidation and
plutonium(VI) reduction have been estimated and their dependences upon the concentrations of nitric acid, plutonium(IV) and
plutonium(VI) as well as upon the dose rate investigated. An equation has been derived which permits to calculate the concentrations
of plutonium(IV) and plutonium(VI) at any desired time. 相似文献
13.
The Na(+) ion encapsulated within the Preyssler heteropolyoxoanion, [NaP5W30O110](14-), was exchanged with Pu(III) under hydrothermal conditions to obtain [Pu(III)P5W30O110](12-) (abbreviated [PuPA](12-)) with hybrid electrochemical properties resulting from the combination of the key redox behaviors of the Pu cation and the P-W-O anion. The electroanalytical chemistry of this two-center, multielectron redox system in a 1 M HCl electrolyte shows that Pu(III) is oxidized to Pu(IV) at the half-wave potential, E(1/2), of +0.960 V versus Ag/AgCl, which is 0.197 V more positive than the corresponding electrode potential for the Pu(III) aqua ion also in 1 M HCl, indicating the stabilization of the trivalent Pu cation by its encapsulation in the Preyssler polyoxometalate (POM). This effect is uncommon in actinide-POM chemistry, wherein electrode potential shifts of the opposite nature (to more negative values), leading to the stabilization of the tetravalent ions by complexation, are renowned. Moreover, in cyclic voltammetry measurements of the Pu(III) aqua ion and [PuPA](12-), the peak currents, i(p), for the one-electron Pu(III)/Pu(IV) processes show different dependencies with the scan rate, nu. The former shows proportionality with nu(1/2), indicating freely diffusing species, whereas the latter shows proportionality with nu, indicating a surface-confined one. The first of the five successive two-electron, W-centered reduction processes in [PuPA](12-) occurs at E(1/2) = -0.117 V versus Ag/AgCl, which is 1.077 V less than the E(1/2) for the Pu(III)/Pu(IV) oxidation, thereby providing an experimental, electrochemical measure of the highest occupied molecular orbital/lowest unoccupied molecular orbital energy gap, which compares well with values previously obtained by density-functional theory, complete active space-self consistent field, and post-Hartree-Fock calculations for a series of M(n+)-exchanged systems, [MPA](n-15) for 1 < or = n < or = 4 (Fernandez, J. A.; Lopez, X.; Bo, C.; de Graff, C.; Baerends, E. J.; Poblet, J. M. J. Am Chem. Soc. 2007, 129, 12244-12253). It was not possible to prepare the Np-exchanged Preyssler anion in the manner of [PuPA](12-), because of the instability of tri- and tetravalent Np to oxidation and the formation of the neptunyl(V) ion, which also could not be exchanged for Na(+). 相似文献
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Tuzimski T 《Journal of AOAC International》2010,93(6):1748-1756
The application of TLC with a diode array detector (TLC-DAD) and HPLC-DAD after SPE for identification and quantitative analysis of pesticides in water samples is demonstrated. The procedures described for the determination of compounds are inexpensive and can be applied to routine analysis of analytes in water samples after preliminary cleanup and concentration by SPE. Average recoveries for four different cartridges and three solvents by the proposed HPLC-DAD method after SPE also are presented. The efficiency of the SPE procedure was evaluated using real water samples from the Zemborzycki Reservoir, near Lublin, southeastern Poland. The method was validated for precision, repeatability, and accuracy. 相似文献
17.
An investigation of the state of terbium and neodymium ions in solutions of various supporting electrolytes was conducted using an analysis of the electronic absorption spectra of Nd(II) and the fluorescence spectra of Tb(III). The supporting electrolytes selected were the salts LiSCN, LiCl, MgCl2, NaCl, and CsCl, the concentration of which was varied within wide limits. The neodymium and terbium chloride concentrations were kept constant in all the solutions and equal to 0.015 and 0.03 M, respectively. To eliminate the influence of hydrolysis on the experimental results, all the solutions were acidified with hydrochloric acid (0.1 M).St. Petersburg University. Translated from Zhurnal Strukturnoi Khimii, Vol. 34, No. 2, pp. 105–111, March–April, 1993. 相似文献
18.
J. Solecki 《Journal of Radioanalytical and Nuclear Chemistry》2004,262(3):759-766
The adsorption of 90Y on various types of soil samples representing successive horizons was studied. The adsorption process can be described by
a Freundlich isotherm and was influenced by the soil type and the horizon's depth. Hydrogen ions did not have a significant
influence on the adsorption of 90Y.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
19.
R. T. Chitnis S. G. Talnikar R. G. Bhogale S. K. Patil 《Journal of Radioanalytical and Nuclear Chemistry》1979,50(1-2):53-60
Fluoride complexing of Pu(IV) has been studied by controlled-pontential coulometry at an ionic strength of 1.0. The values
of β1 and β2 have been found to be 4.6·104 and 2.1·107, respectively. 相似文献