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51.
M. K. Pham M. Betti P. P. Povinec M. Benmansour V. B��nger J. Drefvelin C. Engeler J. M. Flemal C. Gasc�� J. Guillevic R. Gurriaran M. Groening J. D. Happel J. Herrmann S. Klemola M. Kloster G. Kanisch K. Leonard S. Long S. Nielsen J.-S. Oh P. U. Rieth I. ?stergren H. Pettersson N. Pinhao L. Pujol K. Sato J. Schikowski Z. Varga V. P. Vartti J. Zheng 《Journal of Radioanalytical and Nuclear Chemistry》2011,288(2):603-611
A new certified reference material (CRM) for radionuclides in sea water from the Irish sea (IAEA-443) is described and the results of the certification process are presented. Ten radionuclides (3H, 40K, 90Sr, 137Cs, 234U, 235U, 238U, 238Pu, 239+240Pu and 241Am) have been certified, and information values on massic activities with 95% confidence intervals are given for four radionuclides (230Th, 232Th, 239Pu and 240Pu). Results for less frequently reported radionuclides (99Tc, 228Th, 237Np and 241Pu) are also reported. The CRM can be used for quality assurance/quality control of the analysis of radionuclides in water samples, for the development and validation of analytical methods and for training purposes. The material is available in 5 L units from IAEA (http://nucleus.iaea.org/rpst/index.htm). 相似文献
52.
Utilization of Slovak bentonites in deposition of high-level radioactive waste and spent nuclear fuel 总被引:2,自引:0,他引:2
Michal Galambo? Ol��ga Rosskopfov�� Jana Kuf?��kov�� Pavol Rajec 《Journal of Radioanalytical and Nuclear Chemistry》2011,288(3):765-777
The basic strategic aims in the field of managing high-level radioactive waste and liquidation of nuclear power plants are all contained in the Energy policy of the Slovak Republic. Its aim is to resolve the concept of the backside of the nuclear energetics fuel cycle??long-term deposition of high-level radioactive waste and spent nuclear fuel (SNF). The most important form of high-level radioactive waste and SNF long-term deposition is their deposition in deep geological formations created by natural as well as engineering barriers used to isolate the long-lived radionuclides from the biosphere. The basic components of these barriers are clays, of which bentonite is generally referred to as the most suitable clay material. There are a few significant bentonite deposits in the Slovak Republic: Jel?ový potok, Kopernica, Lastovce, Lieskovec, Dolná Ves. The review article summarizes the information on geotechnical properties of Slovak bentonites published up-to-date, which is inevitable to know for the intention of their use. It highlights the advantages and shows drawbacks of five Slovak deposits. It suggests further research direction, to draw a thorough hydraulical, microbial and radiation profile of Slovak bentonites. 相似文献
53.
P. K��d��r K. Varga B. Baja Z. N��meth N. Vajda Zs. Stef��nka L. K?v��r I. Cserny J. T��th T. Pint��r J. Schunk 《Journal of Radioanalytical and Nuclear Chemistry》2011,288(3):943-954
Within the frame of a joint project, the accumulation of the uranium and transuranium (TRU) species on some structural materials used at Soviet made VVER-type pressurized water reactors (such as heat exchanger tube of steam generators and stainless steel canister material) has been studied. The experiments were carried out in a laboratory model system. During the sorption studies, boric acid coolants provided by the Paks Nuclear Power Plant (Paks NPP) were circulated for a period of 30 h. Solution and tube samples obtained in the course of above experiments were analyzed by independent methods (??- and ??-spectrometry, ICP-MS, SEM-EDX, voltammetry and XPS). The experimental results reveal that: (i) the surface excess of the TRU nuclides studied is extremely low (less than 1% of a monolayer coverage); (ii) the surface excess of uranium species measured on the SG tube surfaces is significantly higher, after 30 h sorption period (??sample = 1.0 ??g cm?2 U ? 3.7 × 10?9 mol cm?2 UO2) exceeds a monolayer coverage; (iii) the mechanistic features of the contamination processes (specific or non-specific adsorption, deposition of colloidal and/or disperse particles) depend decisively upon the nature of the studied radionuclides and the chemical structure and composition of the oxide layer formed on stainless steel surfaces. 相似文献
54.
Zal U��yun Wan Mahmood Che Abd Rahim Mohamed Zaharudin Ahmad Abdul Kadir Ishak 《Journal of Radioanalytical and Nuclear Chemistry》2011,287(1):255-260
A total of eight sediment cores with 50 cm length were taken in the Sabah and Sarawak coastal waters using a gravity corer in 2004 to estimate sedimentation rates using four mathematical models of CIC, Shukla-CIC, CRS and ADE. The average of sedimentation rate ranged from 0.24 to 0.48 cm year?1, which is calculated based on the vertical profile of 210Pbex in sediment core. The finding also showed that the sedimentation rates derived from four models were generally shown in good agreement with similar or comparable value at some stations. However, based on statistical analysis of paired sample t-test indicated that CIC model was the most accurate, reliable and suitable technique to determine the sedimentation rate in the coastal area. 相似文献
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56.
Laura Hinojosa Reyes Jorge Luis Guzm��n Mar Aracely Hern��ndez-Ram��rez Juan Manuel Peralta-Hern��ndez Juan Manuel Alfaro Barbosa H. M. Skip Kingston 《Mikrochimica acta》2011,172(1-2):3-14
The application of microwave-assisted extraction (MAE) to the work-up of environmental and biological samples in the study of mercury speciation analysis has increased in recent years and is now increasingly accepted as a standard approach. The review provides a brief theoretical background of microwave heating and the basic principles of microwave energy used for extraction. The advantages and disadvantages of (a) MAE techniques, (b) the influence of the main parameters affecting the extraction, (c) statistical optimization approaches, and (d) strategies for method validation also are highlighted. Recent applications of MAE to mercury species analyses in biological samples, soils, sediments, and crude oil samples are surveyed and critically reviewed. In addition, comparisons of its use with other well-established extraction procedures are discussed. Figure
Microwave-assisted extraction has become a very useful sample preparation techniques in the study of mercury speciation in environmental and biological samples 相似文献
57.
Barbara Le?niewska Monika Kosi��ska Beata Godlewska-?y?kiewicz El?bieta Zambrzycka Agnieszka Z. Wilczewska 《Mikrochimica acta》2011,175(3-4):273-282
An ion-imprinted polymer (IIP) was obtained by copolymerization of methacrylic acid (as a functional monomer) and ethylene glycol dimethacrylate (as a crosslinking agent) in the presence of various chelators for Pt(II) ion and using 2,2??-azo-bis-isobutyronitrile as the initiator. Specifically, acetaldehyde thiosemicarbazone (AcTSn) and benzaldehyde thiosemicarbazone (BnTSn) were used as chelators. The IIPs were applied as sorbents for solid-phase extraction of Pt(II) and Pt(IV) ions from aqueous solutions. The effects of acidity and flow rate of the sample, of elution conditions and of potentially interfering ions were investigated. The imprinting effect of analyte is clearly demonstrated by the fact that only the IIP is capable of quantitative retention of Pt(II) and Pt(IV) ions. The method works best in the pH range from 0.5 to 1 and from 3.5 to 9.5. The ions can be recovered with an acidic solution of thiourea. The Pt-AcTSn polymer displays better sorption properties for the separation of analytes. The selectivity coefficients of the Pt-AcTSn and control polymers for Pt(IV) in the presence Pd(II), Rh(III), Ru(III), Al(III) and Cu(II) were calculated, and the sorbent capacity for Pt(IV) was found to be 4.56???g?g?-1. The method was successfully applied to the determination of Pt(IV) by electrothermal atomic absorption spectrometry in tap water, tunnel dust and anode slime samples. Figure
The new ion imprinted polymers based on Pt(II)-thiosemicarbazone derivative chelates were prepared and used as solid phase extraction sorbent for selective separation of platinum. The method was successfully applied to the determination of analyte in environmental samples by electrothermal atomic absorption spectrometry 相似文献
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59.
V. Yu. Rad��kov G. G. Skvortsov G. K. Fukin K. A. Lyssenko M. Yu. Antipin A. A. Trifonov 《Russian Chemical Bulletin》2011,60(5):803-808
The reaction of lithium silylamide [??o-MeOC6H4N(SiMe3)}Li(OEt2)]2 with 2 equiv. of benzonitrile in THF at ??20 °C affords the lithium derivative of the new tridentate amidinate ligand [{o-MeOC6H4NC(Ph)N(SiMe3)}Li]2. The X-ray diffraction study showed that this complex has a dimeric structure due to the coordination of the N atoms and the ether group of one amidinate ligand to different Li atoms. The reaction of anhydrous YCl3 with the resulting complex in THF gives the monoamidinate complex [{o-MeOC6H4NC(Ph)N(SiMe3)}YCl2(THF)2]2 regardless of the reagent ratio. The latter has a dimeric structure in the crystalline state as a result of the presence of two ??2-bridging Cl atoms that link Y atoms. The ether groups of the amidinate ligands are not involved in the metal-ligand interaction. 相似文献
60.
E. G. Gal��pern A. R. Sabirov Yu. N. Novikov I. V. Stankevich 《Russian Chemical Bulletin》2011,60(8):1556-1563
The modeling of the molecular and electronic structures of the following mono- and biosmium complexes of fullerene C60 was performed by quantum chemical methods (MNDO/PM3 and DFT/PBE): (??2-C60)[Os(PPh3)2(CO)CNMe], (??2,??2-C60)[Os(PPh3)2(CO)(CNMe)]2, (??2-C60)[Os(PH3)2(CO)H], (??2,??2-C60)[Os(PH3)2(CO)H]2, (??2-C60)[Os(PH3)2(CO)CNMe], (??2,??2-C60)[Os(PH3)2(CO)CNMe]2, and (5-C60H5)[Os(C5H5)], (5, 5-C60H10)[Os(C5H5)]2.The osmium atoms in the first six complexes are ??2-coordinated by fullerene C60. In the last two complexes, the ??5-coordination mode is observed. The structures of the radical anions of these complexes were calculated. The energies of the frontier orbitals were evaluated. The acceptor properties of the complexes are discussed. The electron affinities were estimated in two ways: from the energy of the lowest unoccupied molecular orbital (LUMO) and as the energy difference between the neutral molecule and its radical anion. 相似文献