Journal of nuclear and radiochemical sciences最新文献

{"title":"Application of PIGE to Determine Fluorine Concentration in Human Teeth : Contribution to Fluorosis Study","authors":"H. Salah, N. Arab","doi":"10.14494/JNRS2000.8.31","DOIUrl":"https://doi.org/10.14494/JNRS2000.8.31","url":null,"abstract":"In human nutrition fluorine plays a dual role; to prevent tooth decay at a certain level of intake 1,2 and to cause serious damages in bony and dental tissues. When restrained to low level, it can play a role of an inhibitor against certain enzyme systems. But, an excessive ingestion can result in dental fluorosis and bone abnormalities. Skeletal changes and mottled enamel may result when drinking water content of fluorine exceeds few ppm. There is worldwide evidence that fluorine intake above tolerance levels over certain period leads to cumulative effect resulting in systemic illness and osteosclerosis. Several dental fluorosis has been associated with developmental disturbances of ossification. However, bone can be affected at all ages. Clinical inspection constitutes a belated diagnostic and when the harmful effect of fluorine is recognised, no treatment or medicine can be applied. Since fluorine is beneficial at trace amounts, it can not be subtracted from human nutrition. An optimisation of fluorine intake is of a vital importance and this requires deep knowledge of the mechanisms of both of its beneficial and harmful actions on the organism and a sensitive method for its analysis. Conventional methods such as potentiometry are suitable when samples to be analyzed are fluids. These techniques necessitate sample preparations that limit their efficacy and are, usually, destructive. The well known methods for trace elements analysis are the IBA (Ion Beam Analysis) techniques for their advantage to be non destructive and to provide concentrations with high sensitivity. For elements such as Li, Be, B, and F, nuclear reaction analysis with γ-ray emission is recommended. This technique provides quantitative and efficient measurements with sensitivity better than 0.1% for light elements. The γ-ray peaks are generally well isolated and the energy is high enough that correction for absorption is not necessary. No special preparation is needed for the samples. This gives the possibility to analyse the sample without affecting its morphology, allowing fluorine mapping. Having high sensitivity, PIGE is suitable to analyse volatile elements such as fluorine. It permits also the analysis of a great number of samples under same conditions, which result in an accurate comparison. The 19 F(p, αγ) 16 O reaction","PeriodicalId":16569,"journal":{"name":"Journal of nuclear and radiochemical sciences","volume":"70 1","pages":"31-34"},"PeriodicalIF":0.0,"publicationDate":"2007-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76204253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploring the Frontiers of Nuclear and Radiochemistry","authors":"D. Hoffman","doi":"10.14494/JNRS2000.8.35","DOIUrl":"https://doi.org/10.14494/JNRS2000.8.35","url":null,"abstract":"Frontiers in fundamental research on both nuclear and chemical properties and prospects for future advances were highlighted in this two-day Symposium. The following four areas were especially emphasized: Superheavy elements − production, chemical and nuclear properties, and potential use of the unique techniques developed to solve applied problems; Nuclear processes as chemical probes to explore environmental and ecological radionuclide distributions; Application of nuclear and radiochemical techniques to geochemical, pharmaceutical, and biological sciences, and even information technology; Environmental radiochemistry and fundamental actinide sciences and practical applications in nuclear waste storage and remediation. These topics were explored in both invited lectures and poster presentations. The Global Nuclear Energy Program recently proposed by the U. S. is briefly described and the potential need for scientists with expertise in nuclear and radiochemistry and actinide science, and the opportunities for synergistic interactions are highlighted.","PeriodicalId":16569,"journal":{"name":"Journal of nuclear and radiochemical sciences","volume":"19 1","pages":"35-38"},"PeriodicalIF":0.0,"publicationDate":"2006-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85189995","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Measurement of 26Al in Terrestrial Silicate Rock, Revisited","authors":"S. Shibata, Y. Okuda, K. Takamiya, Y. Oki, T. Sasaki, H. Matsuzaki, K. Sakamoto","doi":"10.14494/JNRS2000.7.2_33","DOIUrl":"https://doi.org/10.14494/JNRS2000.7.2_33","url":null,"abstract":"Al (T1/2 = 7.2 × 10 y) observed in terrestrial and extraterrestrial matters provides one of the important clues to the deciphering fossil records stored in those materials and allows investigations of their irradiation history by cosmic radiation. In their pioneering work in 1968, Tanaka et al. searched for Al produced in terrestrial silicate rock (chert) by the interaction of muons with Si, which is the most abundant isotope in the earth’s crust except for O, in order to investigate the secular variation of cosmic radiation intensity. They chemically extracted and purified aluminum from several tens of kg of silicate rock collected from an area with a low erosion rate. The aluminum separated was ignited to Al2O3. Each 100 g of the Al2O3 was pressed into a disk of 7 cm in diameter and 2 cm thick. The annihilation γ rays from the decay of Al in these samples were measured using a low-background γ−γ coincidence spectrometer consisting of two 7.6 × 7.6 cm NaI(Tl) crystals installed in the underground counting facility. Unfortunately, they were not able to obtain the positive results, and reported the Al activities of 0.02 ± 0.12 dpm/10 kg SiO2 for the surface rock and of 0.00 ± 0.08 dpm/10 kg SiO2 for the sample collected at a depth of 24 meters of water equivalent (mwe). In 1975, Hampel et al. measured again the same sample prepared by Tanaka et al. by means of a low-level γ−γ coincidence spectrometry system consisting of two 15 × 10 cm NaI(Tl) crystals with improved statistics. For the measurement, four original disks of the sample 1A prepared from the surface rock by Tanaka et al. was repressed into a larger disk (a 402 g disk of Al2O3) of 15 cm in diameter and 1.65 cm thick. The result was reported to be 0.0068 ± 0.0028 dpm Al/kg SiO2. Based on the result, they discussed the muon flux during the last several million years and the erosion rate at the collecting location of the measured sample. In the conclusion of their paper, a more quantitative measurement in the future was expected for wide applications of cosmic-ray-produced longlived nuclides in geology, geophysics, and cosmic ray physics. For trace analyses of long-lived nuclides, accelerators have now extensively been applied as high-energy and extremely high-sensitive mass spectrometers, accelerator mass spectrometry (AMS). By the advances in AMS, it became possible to apply cosmogenic radionuclides produced in situ in terrestrial samples for studies of erosion and sedimentation rates and surface exposure ages. Recently, quartz, which is geologically abundant mineral, is used as one of the ideal samples for these studies. We have applied the AMS method to measure the trace amount of cosmogenic radionuclides produced in terrestrial and extraterrestrial substances. In the course of this study, Al induced by cosmic ray secondaries in terrestrial silicate rock was measured in order to confirm the result reported by Hampel et al. While the large amount of the rock sample is needed for the radi","PeriodicalId":16569,"journal":{"name":"Journal of nuclear and radiochemical sciences","volume":"7 1","pages":"33-35"},"PeriodicalIF":0.0,"publicationDate":"2006-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90453215","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mossbauer Investigation into the Reactions of Laser-evaporated Iron with Solid Oxygen at Low Temperatures","authors":"Y. Yamada, S. Hirayama","doi":"10.14494/JNRS2000.7.2_17","DOIUrl":"https://doi.org/10.14494/JNRS2000.7.2_17","url":null,"abstract":"Laser-ablation has been studied extensively and has been applied to many fields including the surface treatment of solids and the formation of thin films. Laser-evaporation is a very useful method for vaporizing various kinds of materials without causing radiant heating of surrounding materials. This makes it a convenient method for vaporizing materials near a cold head in a cryostat in order to study low-temperature reactions. We have previously reported reactions of laser-evaporated iron atoms with various reactant gases using a low temperature matrix isolation technique and Mossbauer spectroscopy. 1-4 The reactions of laser-evaporated iron atoms with oxygen produced FeO, Fe(O2), FeO3, (O2)FeO2, and OFeO which are reaction products of the gas phase and are trapped in a low temperature Ar matrix. 5 We have also reported laserdeposition of Fe metal onto Al or Si substrates at various temperatures, 6 and the formation of Fe-Al alloy or Fe-Si compounds was observed at the boundary between the Fe-films and the Al or Si substrate. Laser-deposition of hematite or magnetite onto Al substrates produced iron oxide films whose composition varied depending on the substrate temperature. 7 Thereby laser-deposition has the possibility of producing functional films whose chemical compositions and physical properties can be controlled. Here, we report the reactions of laser-evaporated Fe with solid oxygen at 20 K. While the experimental setup is very similar to that employed in our previous matrix-isolation studies, 5 in this study the Fe atoms and O2 gas are introduced alternately to the cold substrate in order to investigate the reaction of Fe with solid oxygen rather than the gas-phase reactions. This study is also a useful cross reference for the 57 Mn in-beam Mossbauer study of solid oxygen, 8 although the densities of 57 Fe and 57 Mn atoms are very different. Furthermore the reac","PeriodicalId":16569,"journal":{"name":"Journal of nuclear and radiochemical sciences","volume":"40 1","pages":"17-20"},"PeriodicalIF":0.0,"publicationDate":"2006-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90466400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modeling the Sorption Kinetics of Cesium and Strontium Ions on Zeolite A","authors":"K. A. El-Rahman, M. R. El-Sourougy, N. Abdelmonem, I. Ismail","doi":"10.14494/JNRS2000.7.2_21","DOIUrl":"https://doi.org/10.14494/JNRS2000.7.2_21","url":null,"abstract":"Zeolite A was chemically synthesized and characterized using X-ray diffraction, X-ray fluorescence, and thermal analysis. The sorptive removal of cesium and strontium ions from aqueous waste solution using synthetic zeolite A was investigated. Experiments were carried out as a function of pH, solute concentration, and temperature (298–333 K). Analysis of the respective rate data in accordance with three kinetic models revealed that the intraparticle diffusion was the rate determining step for the sorption of both studied ions. Values of the pseudo first order and pseudo second order rate constants and the particle diffusion coefficients were determined from the graphical representation of the proposed models. Activation energy and thermodynamic parameters of free energy (∆ G*), enthalpy (∆ H*), and entropy (∆ S*) of activation for each sorption process were calculated from the linearized form of Arrhenius equation.","PeriodicalId":16569,"journal":{"name":"Journal of nuclear and radiochemical sciences","volume":"74 1","pages":"21-27"},"PeriodicalIF":0.0,"publicationDate":"2006-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85796574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mössbauer Study on the Electron Transfer Rate Depending on the Intermolecular Interaction in Iron (II, III) Mixed-Valence Complex","authors":"Natsuko Motokawa, S. Hayami, Masahiko Yamamoto, Y. Maeda","doi":"10.14494/JNRS2000.7.2_N5","DOIUrl":"https://doi.org/10.14494/JNRS2000.7.2_N5","url":null,"abstract":"active sites of metalloproteins play important roles in biological systems. The model compounds of these compounds have been studied intensively and characterized by using various methods. One of the model complexes is a family of carboxylato mixed-valence diiron(II,III) complexes. For example, mixed-valence diiron complexes with a heptadentate polypyridine ligand (bpmp), the ligand having imidazol groups (bimp), and the ligand having phenol groups (bbpmp), have been reported previously (scheme 1). In the investigation of mixed-valence complexes with such ligands, knowledge of the mechanism of the electron transfer between the two iron centers is most important. Furthermore, in the field of nanomaterial science, understanding the electron transfer phenomena at single molecule level is also important. The mixed-valence diiron(II,III) bpmp complexes with various carboxylic acid were reported by Maeda et al. previously, and characterized by using Mössbauer spectroscopy. They reported that the electron trapped/detrapped states are affected by the kind of carboxylic acids, being bridging ligands. They also suggested that the rate of the intramolecular electron transfer is influenced by the crystal packings. Therefore it is thought that the intermolecular interactions play an important role in the electron transfer of the mixed-valence state. We focused on the intermolecular interactions in the mixed-valence state, and prepared two types of samples of the mixed-valence diiron(II,III) compound [FeFe(bpmp) (ena)2](ClO4)2, where Hbpmp represents 2,6-bis[bis-(2-pyridylmethyl)-aminomethyl]-4-methylphenol and Hena represents enanthic acid (Figure 1). One is a polycrystalline sample as prepared and the other is a film sample. The film sample was prepared by mixing an acetonitrile solution of poly(methyl methacrylate) (PMMA) and an acetonitrile solution of the complex, and obtained as a transparent film. In the film sample, the complex molecules were dispersed completely at a single molecular level and thus the intermolecular interaction would be very weak. Herein, we report that the rates of the electron transfer for the polycrystalline and film samples are different, depending on the strengths of the intermolecular interactions. Hereafter, the polycrystalline sample of [FeFe(bpmp)(ena)2](ClO4)2 is represented as 1, and the film sample as 2. Mössbauer Study on the Electron Transfer Rate Depending on the Intermolecular Interaction in Iron(II, III) Mixed-Valence Complex","PeriodicalId":16569,"journal":{"name":"Journal of nuclear and radiochemical sciences","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2006-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87739810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative Study on Bromide and Iodide Ion-Isotopic Exchange Reactions Using Strongly Basic Anion Exchange Resin Duolite A-113","authors":"R. Lokhande, P. Singare, M. Dole","doi":"10.14494/JNRS2000.7.2_29","DOIUrl":"https://doi.org/10.14494/JNRS2000.7.2_29","url":null,"abstract":"","PeriodicalId":16569,"journal":{"name":"Journal of nuclear and radiochemical sciences","volume":"20 1","pages":"29-32"},"PeriodicalIF":0.0,"publicationDate":"2006-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84894507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Dependency on the Dissipation Tensor of Multi-modal Nuclear Fission","authors":"T. Asano, T. Wada, M. Ohta, S. Yamaji, H. Nakahara","doi":"10.14494/JNRS2000.7.7","DOIUrl":"https://doi.org/10.14494/JNRS2000.7.7","url":null,"abstract":"In the study of the fission of actinide nuclei at low excitation energies including the spontaneous fission, it was found that the fragment mass distribution and the total kinetic energy (TKE) distribution consist of more than one component, in contrast to the simple single peak structure that is found in the fission at high excitation energies. 1– 6 This phenomenon is attributed to the existence of more than one fission path and is called the multi-modal fission. The mass and TKE distributions depend sensitively on the excitation energy and the position of the peaks of the mass distribution suggests the influence of the closed shell structure of the fragments. Therefore, it is supposed that the microscopic energy plays an important role for the manifestation of this phenomenon. It is a great challenge for us to understand this phenomenon in terms of nuclear many-body dynamics. Several authors studied the potential energy surface (PES) including the microscopic energy in a multi-dimensional parameter space that describes various nuclear shapes; one can deduce the possible fission paths by studying the location of the saddle points and the fission valleys in multi-dimensional parameter space. 7 With this method, they could explain the general trend of the position of the peaks of the mass distribution. The dynamical point of view is necessary to progress the study of the fission mode. We have applied the Langevin approach to the study of the fission modes in uranium nuclei and in fermium nuclei. 8–10 We studied the mass and TKE distributions and demonstrated that we can decompose the fission events into several components by tracing the Langevin trajectories. We also studied the isotope dependence and the excitation energy dependence of the fission mode. 8–10 In the previous studies, we adopted the wall-and-window type one-body friction as the dissipation mechanism of the nuclear fission dynamics. The validity of this dissipation mechanism has been demonstrated by one of the authors (T.W.) who studied the dissipation tensor dependence of the pre-scission neutron multiplicity and the mean TKE. 11–14 From the comparison of the results of the dynamical calculation with experimental data, they excluded the possibility of the two-body type dissipation to be the dominant mechanism by showing that it cannot reproduce the pre-scission neutron data and the TKE data simultaneously. On the other hand, they showed that the wall-and-window type one-body friction can reproduce both data reasonably well and concluded that it is a reasonable model for the dissipation mechanism of nuclear fission. There are other models that are of one-body nature, e.g. surface-plus-window formula, modified wall-and-window formula and chaos weighted wall formula. 15–17 Though there were no free parameters in the original derivation of the one-body friction, 18, 19 the strength has been modified frequently in order to reproduce some experimental data. For example, in the study of t","PeriodicalId":16569,"journal":{"name":"Journal of nuclear and radiochemical sciences","volume":"14 1","pages":"7-11"},"PeriodicalIF":0.0,"publicationDate":"2006-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84350413","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Global Comparison of TALYS and ALICE Code Calculations and Evaluated Data from ENDF/B, JENDL, FENDL, and JEFF Files with Measured Neutron Induced Reaction Cross-sections at Energies above 0.1 MeV","authors":"C. Broeders, A. Konobeyev, L. Mercatali","doi":"10.14494/JNRS2000.7.N1","DOIUrl":"https://doi.org/10.14494/JNRS2000.7.N1","url":null,"abstract":"The goal of the work is the study of uncertainties in the calculation of activation and transmutation cross-sections for neutron induced reactions using nuclear models and codes having direct relation to the generation of nuclear data files. The calculations were performed with the TALYS code and the ALICE/ASH code, which have been extensively used for nuclear data evaluation during the last decade. The results of calculations are compared with experimental cross-sections from EXFOR for neutron induced reactions for nuclei from Al to Bi. The comparison is done for main reaction channels, for which experimental data are available, without the distinction. The obtained deviation factors allow to define appropriate models for nuclear reaction cross-section calculation at different mass ranges of target nuclei.","PeriodicalId":16569,"journal":{"name":"Journal of nuclear and radiochemical sciences","volume":"57 12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2006-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73551832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"57Fe Mössbauer Parameters of Two Crystal Polymorphs of Fc+AsF6- and the Sign of the Quadrupole Splitting in the Ferrocenium Ion","authors":"R. Herber, I. Nowik, D. Braga, M. Polito","doi":"10.14494/JNRS2000.7.13","DOIUrl":"https://doi.org/10.14494/JNRS2000.7.13","url":null,"abstract":"Temperature-dependent 57Fe Mossbauer effect spectroscopy has been used to characterize the hyperfine and dynamical properties of the metal atom in two crystallographic forms of ferrocenium hexafluoroarsenate. The temperature dependence of the recoil-free fraction and the spin-lattice relaxation rates have been determined over the interval 89<T<300 K and shows a small difference between the two crystallographic forms. The sign of the quadrupole splitting parameter in the Fc+ cation has been elucidated in a transverse magnetic field experiment at room temperature.","PeriodicalId":16569,"journal":{"name":"Journal of nuclear and radiochemical sciences","volume":"47 1","pages":"13-15"},"PeriodicalIF":0.0,"publicationDate":"2006-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78520337","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}