共查询到20条相似文献,搜索用时 15 毫秒
1.
J. P. W. Houtman 《Journal of Radioanalytical and Nuclear Chemistry》1977,35(1):21-30
This article describes how research planning may lead to a situation where a basis is provided for the cooperation between
a limited group of personel guided by a devotion towards the possibilities and on awareness of the limitations of the nuclear
reactor for analytical purposes and research groups in various sciences such as chemistry, biology, medicine, agriculture,
geology and archeology. Attention is paid to neutron activation analysis, the use of radioisotope tracers and to the specific
requirements set for them by workers in the above mentioned fields. 相似文献
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3.
H. J. Ache 《Journal of Radioanalytical and Nuclear Chemistry》1988,124(2):415-430
The selection of newly developed analytical and radioanalytical methods for the determination of trace and matrix elements in medium activity wastes is discussed. 相似文献
4.
E. Havránek A. Bumbálová J. Čižmárik 《Journal of Radioanalytical and Nuclear Chemistry》1984,85(1):21-31
The applicability of two nuclear analytical methods for the determination of hepatacaine hydrochloride in solution was studied, i. e. radionuclide X-ray fluorescence analysis and radiometric titrations based on precipitate formations. Methods used were evaluated on the basis of obtained sensitivity values. 相似文献
5.
Among nuclear analytical techniques, neutron activation analysis (NAA) is particularly useful for environmental studies. It affords low detection limits for many elements, high specificity and few sources of systematic error, which means that high accuracy is attainable. Neutron activation analysis is particularly useful for trace and ultra-trace analysis of environmental samples (water, soils, rocks and biological material). In trace element work associated with pollution, instrumental NAA is a powerful technique for multi-element surveys, in particular when combined with other spectroscopic techniques. Nuclear techniques, as with most analytical techniques, cannot be used to distinguish between different physico-chemical forms of an element per se. When used in combination with appropriate separation techniques, however, nuclear techniques can provide valuable information about trace element speciation in environmental and biological systems. From dynamic tracer experiments, i.e., addition of chemically well defined labelled compounds to environmental systems, valuable information can be obtained on the distribution of species and on microchemical processes influencing the physico-chemical forms. In these laboratories, speciation studies on trace elements in natural waters have been carried out by using instrumental NAA in combination with physical separation techniques, such as dialysis and ultrafiltration, in situ and in the laboratory. Dynamic radiotracer experiments have provided important information about processes influencing the speciation of trace elements in aquatic systems. Sequential extraction techniques have proved to be useful in studies on sediments and soils when combined with NAA. Sequential extractions also provide significant information about the physico-chemical behaviour of radionuclides supplied to natural soils from the Chernobyl accident. 相似文献
6.
Sumin Hu Xueying Mao Zhifang Chai Hongfei Wang Hong Ouyang Jianjun Zhang 《Journal of Radioanalytical and Nuclear Chemistry》2004,259(3):369-373
Neutron activation analysis (NAA) and dual energy X-ray absorptiometry (DEXA) have been used to study the effects of different
calcium supplements on osteoporosis, including calcium carbonate, calcium threonate, calcium gluconate, calcium lactate, calcium
acetate and a traditional Chinese medicine. Animal test results showed that calcium carbonate, calcium gluconate, calcium
acetate and the Chinese medicine notably increased osteoporotic rat's femoral bone mineral density (BMD). Also, calcium carbonate,
calcium acetate and the Chinese medicine significantly increased osteoporotic rat's vertebral BMD. But calcium L-threonate
and calcium lactate had no such effects. Calcium gluconate, calcium acetate and the Chinese medicine improved the bone mechanical
intensity of osteoporotic rats. The results of NAA showed that the loss of elements in spongy bones was more seriously than
that in compact bone and was difficult to be improved.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
7.
W. Maenhaut G. Ducastel R. E. Hillamo T. A. Pakkanen J. M. Pacyna 《Journal of Radioanalytical and Nuclear Chemistry》1993,167(2):271-281
Atmospheric aerosol samples were collected during spring sampling campaigns in 1988 and 1989 at Birkenes and Nordmoen in southern Norway. The aerosol collectors used included stacked filter units (SFUs), a low volume sampler (referred to as ILVS), which consists of a filter preceded by three impaction stages, and an 11-stage Berner low-pressure impactor (LPI). All samples were analyzed for up to about 40 elements by INAA and PIXE. The resuls obtained from parallel samplings were intercompared in terms of ratios ILVS/SFU and LPI/SFU, whereby these ratios were calculated separately for the coarse and fine size fractions. For the ILVS/SFU parallel samplings, excellent agreement was observed between the results for the fine fraction, with the overall mean average ratio (based on 21 samples and 22 elements) being 0.99±0.10. For the coarse fraction, the overall mean ILVS/SFU ratio (based on 21 elements) was 0.75±0.13. This low result is explained by different upper-particle-size cut-offs of the two samplers. For the parallel samplings with LPI and SFU, the agreement was poorer, but still reasonable. The atmospheric concentrations observed at the two sites in the two campaigns and also the LPI size distributions for the various elements are discussed briefly. 相似文献
8.
Technological process of welding is significant source of pollution of working environment with heavy metals. Evaluation of chemical quality of working environment was made by means of radionuclide X-ray fluorescent analysis and activation analysis with fast neutrons. Welding aerosols were sampled by filtration method on Synpor 4 membrane ultra-filters. For selected types of welding filter metals, determination of heavy metals in aerosols was performed. 相似文献
9.
Chromatographic techniques are very frequently used in analytical procedures for the separation, determination and identification of a wide spectrum of analytes present in samples with complex and sometimes variable matrices. However, the estimation of uncertainty of the final results does not include the uncertainties associated with the actual chromatographic process. In effect, such results cannot always be treated as a reliable source of analytical information. In this paper we present the basic terms, sources of uncertainty, and methods of calculating the combined uncertainty that any presentation of final determinations should include. 相似文献
10.
Alex Tarancón Héctor Bagán José F. García 《Journal of Radioanalytical and Nuclear Chemistry》2017,314(2):555-572
This article is a general overview of the potential capacities of plastic scintillators in radionuclide activity determination. Plastic scintillation (PS) behaves as liquid scintillation does, but with some differences related to the solid state of plastic scintillators. These differences are the base of some drawbacks and some advantages, related to the use of PS. This article describes how these capacities are affected by PS composition, sample preparation, scintillation mechanisms and quenching calibration procedures. It also describes the capabilities for alpha and beta emitter determination and discrimination through the use of PS microspheres and PS resins and their application to different types of samples and radionuclide determination. 相似文献
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An original focus on univariate calibration as an experimental process of quantitative analysis is presented. A novel classification system is introduced against the background of the present situation concerning nomenclature of calibration methods. Namely, it has been revealed that four methods well-known in analytical chemistry: the conventional method, the internal standard method, the indirect method and the dilution method, can be split into those carried out in both the interpolative and the extrapolative mode. It is then shown that the basic procedures of all these methods can be modified including different approaches, such as matrix-matched technique, spiking the sample with a reactant, bracketing calibration, and others. For the first time (as compared to monographies dealing with univariate calibration) it is reviewed how the methods are mixed and integrated with one another thereby creating new calibration strategies of extended capabilities in terms of enhanced resistance to the interference and non-linear effects – as the main sources of systematic calibration errors. As additional novelty, rationally possible combinations of the calibration methods – not met hitherto in the literature – have been predicted. Finally, some general rules relating to calibration are formulated and the main calibration problems that still need to be solved are displayed. 相似文献
13.
A. Gharib H. Rahimi H. Pyrovan N. J. Raoffi H. Taherpoor 《Journal of Radioanalytical and Nuclear Chemistry》1985,89(1):31-44
This work is part of a project with the IAEA, in a coordinated program on Trace Elements in Human and Bio-Environmental Systems to evaluate their nutritional requirements, interrelations and the role of trace elements in health, metabolism, etc. Cow's milk being regarded as one of the most important and nutritious foodstuffs consumed by people. Hence as a first step, an elemental analysis for milk was carried out for this purpose; a few samples of pasteurized milk and local sample were investigated for essential and toxic trace elements. The secondary aim of this project was the assessment of various analytical techniques involved. However, in the present work, the methods involved were AAS, PIXE and NAA. The latter method was applied both instrumentally and radiochemically. Although the results pertaining to the various methods employed are not in good agreement. there is, however, some justification to clarify this internal inconsistency. The precision of NAA and AAS allows a greater degree of acceptance. Although PIXE is very fast and rather routine, the technique for trace element analysis needs certain adaptations and development. 相似文献
14.
Floyd E. Stanley A. M. Stalcup H. B. Spitz 《Journal of Radioanalytical and Nuclear Chemistry》2013,295(2):1385-1393
Nuclear forensic (NF) techniques are critical in responding to both environmental releases of nuclear materials and illicit trafficking activities involving both nuclear and counterfeit materials. Despite rising need, however, significant barriers exist to the future success of such research. This subset of analytical chemistry contains unique concerns (e.g. chronometry and impurity signatures), a wide variety of preparatory/instrumental approaches, and is in need of innovative solutions to current problems both in and out of the lab. The present work introduces existing NF research, development challenges and notes potential areas for advancement by highlighting several key analytical approaches. Examples of concerns and techniques discussed in this review include: chronometry, reference materials, separations, counting spectrometry, mass spectrometry and more. 相似文献
15.
R. M. Parr 《Journal of Radioanalytical and Nuclear Chemistry》1987,110(2):491-502
In human nutrition research, nuclear analytical techniques, particularly neutron activation analysis (NAA), are used mainly for thein vitro study of trace elements. According to work sponsored by the IAEA, up to 15 trace elements and 5 minor elements of nutritional interest may be determined in biological materials by NAA with good accuracy and precision. A programme is described in which NAA was used for the determination of 14 trace elements and one minor element in human milk. NAA also plays an important role in the certification of reference materials for nutritional studies. 相似文献
16.
Statistical evaluation of recorded knowledge in nuclear and other instrumental analytical techniques
Tibor Braun 《Fresenius' Journal of Analytical Chemistry》1987,328(1-2):1-9
Summary The main points addressed in this study are the following: Statistical distribution patterns of published literature on instrumental analytical techniques 1981–1984; structure of scientific literature and heuristics for identifying active specialties and emerging hot spot research areas in instrumental analytical techniques; growth and growth rates of the literature in some of the identified hot research areas; quality and quantity in instrumental analytical research output.
Presented at the IAEA Advisory Group Meeting on Comparison of Nuclear Analytical Methods with Competitive Methods, October 3–7, 1986, Oak Ridge, TN, USA 相似文献
Statistische Auswertung von Veröffentlichungen in nuklearen und anderen instrumentellen analytischen Techniken
Presented at the IAEA Advisory Group Meeting on Comparison of Nuclear Analytical Methods with Competitive Methods, October 3–7, 1986, Oak Ridge, TN, USA 相似文献
17.
J. Orechovska P. Misaelides A. Godelitsas P. Rajec H. Klewe-Nebenius F. Noli E. Pavlidou 《Journal of Radioanalytical and Nuclear Chemistry》1999,241(3):519-527
Pure HEU-type zeolite (heulandite) crystals were allowed to interact with Sr2+ cations in aqueous solution. The powdered solid experimental products obtained from batch-type sorption experiments, using
solutions of Sr2+-concentrations between 10 and 1000 mg/l, were investigated using INAA, RI-XRF and SEM-EDS. The Sr uptake by the mineral which
can adequately be described with a Freundlich-type isotherm, varies from 3.14 to 6.22 mg/g. The distribution coefficients
increase progressively by decreasing the solutions concentration reaching a value of 1800 ml/g. The investigated zeolite interacts
with Sr2+ cations through ion exchange reactions and initial exchangeable Ca2+ cations are replaced into the structural micropores. However, in the best case, only ca. 43% of the theoretical CEC can be
covered because of the limited availability of the extra framework Ca2+ cations that can be removed from the lattice under ambient treatment conditions. The XPS investigation of Sr-loaded single
crystals indicated that adsorption of Sr2+ cations on the outer surface also occurs while surface precipitation phenomena must be excluded. Similar surface analyses
by means of12C-RBS showed that the Sr depth-distribution at near-surface layers is quite homogenous in contrast to a previous relevant
study revealing an intense surface Sr-accumulation on a natural Ca-zeolite of different structural characteristics (scolecite). 相似文献
18.
J. Gomez G. Blondiaux B. Hakim C. Perrin J. L. Debrun 《Journal of Radioanalytical and Nuclear Chemistry》1992,160(1):153-157
Ubiquitous elements like carbon and oxygen always contaminate surfaces and, therefore, are the soucre of important analytical errors at trace level. Even in the case of radioactivation (with charged particles), where the sample can be etched after irradiation, analytical problems exist. In this work, we show that laser desorption/ablation can efficiently clean surfacaes, in the case of GaAs samples, resulting in better analytical conditions. Under ultra high vacuum, these surfaces remain clean long enough, so that the analysis of carbon and oxygen can be carried out using various nuclear methods, according to the needs of the analyst. 相似文献
19.
A. Lucaciu M. V. Frontasyeva E. Steinnes Ye. N. Cheremisina C. Oprea T. B. Progulova L. Staicu L. Timofte 《Journal of Radioanalytical and Nuclear Chemistry》1999,240(2):457-458
This is the first systematic study of air pollution from heavy metals and other trace elements throughout several industrialized
areas and national parks of Eastern Romanian Carpathians using the moss biomonitoring technique. Samples ofHylocomium splendens collected at 120 sites were analyzed by epithermal neutron activation analysis at the pulsed fast reactor IBR-2 at JINR,
Dubna, for a wide range of elements including heavy metals and rare earths (Na, Mg, Al, Cl,K, Ca, Sc, V, Cr, Mn, Fe, Co, Ni
(by (n,p) reaction), Cu, Zn, As, Se, Br, Rb, Sr, Zr, Mo, Ag, Sn, Sb, I, Cs, Ba, La, Ce, Nd, Sm, Eu, Gd, Tb, Yb, Hf, Ta, W,
Au, Th, and U). Copper, lead and cadmium were determined by AAS. Certified Reference Standards of mosses produced for interlaboratory
comparisons in the European moss-survey 1995 were used to ensure the quality of the measurements. To present results in the
form of coloured contour maps the geographical information system GIS-INTEGRO was used. The regional extent of pollution with
specific metals was determined. Results reported are well consistent with those obtained in numerous recent projects carried
out in Germany, the Netherlands, Poland, Bulgaria and other countries. 相似文献
20.
The feasibility of fingerprinting elephant ivory and rhino horn to establish the origin and accordingly promote the sale of legally stockpiled reserves from South Africa into the (closed) world markets have been investigated in the past, and preliminary studies with non-nuclear techniques look promising. The Research Reactor programme within the framework of AFRA is currently becoming bent on applications of nuclear analytical techniques for socio-economic development. It is as part of this AFRA programme, that instrumental neutron activation analysis can possibly be used as a powerful and reliable fingerprinting technique for the determination of the origin of ivory. 相似文献