The discovery of the gamma spectrum abnomal is reported for the uranium ore sample No. 15, In comparison with a parallel investigation on a reference natural uranium saraple the relative abundance of U^235 is obtained...The discovery of the gamma spectrum abnomal is reported for the uranium ore sample No. 15, In comparison with a parallel investigation on a reference natural uranium saraple the relative abundance of U^235 is obtained and the U^233 content of sample No. 15 turns out to be 5 percent higher than that of the reference natural sample, Discussion is given to the mechanism by which U^235 is enriched in the ore.展开更多
O571.435 98031498NSRL光电子能谱实验控制软件设计及其应用=Photoelectron spectroscopy experiment soft-ware conduction and application at NSRL[刊,中]/余小江,徐彭寿,陆尔东,徐世红,张发培,潘海滨,徐长山(中国科技大学国家同步...O571.435 98031498NSRL光电子能谱实验控制软件设计及其应用=Photoelectron spectroscopy experiment soft-ware conduction and application at NSRL[刊,中]/余小江,徐彭寿,陆尔东,徐世红,张发培,潘海滨,徐长山(中国科技大学国家同步辐射实验室.安徽,展开更多
Six low-lying tautomers of 1-methyl-hypoxanthine have been studied at the B3LYP/aug-cc- pVDZ level. Two tautomers NTH and N9H with the comparable energies are far more stable than the others. The vertical ionization e...Six low-lying tautomers of 1-methyl-hypoxanthine have been studied at the B3LYP/aug-cc- pVDZ level. Two tautomers NTH and N9H with the comparable energies are far more stable than the others. The vertical ionization energies of the tautomers calculated with ab initio electron propagator theory in the P3/aug-cc-pVDZ approximation are in agreement with the experimental data from photoelectron spectroscopy. According to the calculated relative energies and the comparison between the simulated and the experimental photoelectron spectra, it demonstrates that there are at least two tautomers of 1-methyl-hypoxanthine in the gas-phase experiments.展开更多
The neutron spectra and angular distributions from （p,n） reactions in the input proton energy range 6-25 MeV were analyzed. These are the old experimental data, however, re-analysis of these data reveals very intere...The neutron spectra and angular distributions from （p,n） reactions in the input proton energy range 6-25 MeV were analyzed. These are the old experimental data, however, re-analysis of these data reveals very interesting peculiarities which never have been discussed before. The high energetic part of neutron spectrum due to the direct mechanism changes considerably from one isotope to other. This difference was described with incorporation of two components which provide the ＂broad bump＂, or ＂step like＂ shape of neutron spectra at high energy. The properties of these components are： different shape, energy shift between them, and very strong fluctuation between different isotopes for ratio of cross sections connected with partial contribution. One may conclude that shape of non-compound neutron spectrum demonstrates very strong （N-Z） odd-even effect. The direct comparison of experimental data, and semi-empirical results with （p,n） spectra predicted by the EMPIRE code, gave evidence that the traditional approach cannot predict this effect. New finding may explain the ＂constant temperature＂ dependence for level density in mass range A-60 discussed in several investigations. These new experimental peculiarities were demonstrated, and it may be considered as reality. At the same time there is not consequent physical model for their explanation. The fact that spectrum shape is correlated with N-Z value may give a hint that discussed effects are connected with ＂halo-neutrons＂.展开更多
With the widespread application of radionuclide ^235U（VI）, it is inevitable that part of U（VI） is released into the natural environment. The potential toxicity and irreversibility impact on the natural environment...With the widespread application of radionuclide ^235U（VI）, it is inevitable that part of U（VI） is released into the natural environment. The potential toxicity and irreversibility impact on the natural environment has become one of the most forefront pollution problems in nuclear energy utilization. In this work, rod-like metal-organic framework （MOF-5） nanomaterial was synthesized by a solvothermal method and applied to efficiently adsorb U（VI） from aqueous solutions. The batch experimental results showed that the sorp- tion of U（Vl） on MOF-5 was strongly dependent on pH and independent of ionic strength, indicating that the dominant interaction mechanism was inner-sphere surface complexation and electrostatic interac- tion. The maximum sorption capacity of U（Vl） on MOF-5 was 237.0 mg]g at pH 5.0 and T = 298 K, and the sorption equilibrium reached within 5 rain. The thermodynamic parameters indicated that the removal of U（VI） on MOF-5 was a spontaneous and endothermic process. Additionally, the FT-IR and XPS analyses implied that the high sorption capacity of U（Vl） on MOF-5 was mainly attributed to the abundant oxygen-containing functional groups （i.e., C-O and C=O）. Such a facile preparation method and efficient removal performance highlighted the application of MOF-5 as a candidate for rapid and efficient radionuclide contamination＇s elimination in practical applications.展开更多
文摘The discovery of the gamma spectrum abnomal is reported for the uranium ore sample No. 15, In comparison with a parallel investigation on a reference natural uranium saraple the relative abundance of U^235 is obtained and the U^233 content of sample No. 15 turns out to be 5 percent higher than that of the reference natural sample, Discussion is given to the mechanism by which U^235 is enriched in the ore.
文摘O571.435 98031498NSRL光电子能谱实验控制软件设计及其应用=Photoelectron spectroscopy experiment soft-ware conduction and application at NSRL[刊,中]/余小江,徐彭寿,陆尔东,徐世红,张发培,潘海滨,徐长山(中国科技大学国家同步辐射实验室.安徽,
文摘Six low-lying tautomers of 1-methyl-hypoxanthine have been studied at the B3LYP/aug-cc- pVDZ level. Two tautomers NTH and N9H with the comparable energies are far more stable than the others. The vertical ionization energies of the tautomers calculated with ab initio electron propagator theory in the P3/aug-cc-pVDZ approximation are in agreement with the experimental data from photoelectron spectroscopy. According to the calculated relative energies and the comparison between the simulated and the experimental photoelectron spectra, it demonstrates that there are at least two tautomers of 1-methyl-hypoxanthine in the gas-phase experiments.
文摘The neutron spectra and angular distributions from （p,n） reactions in the input proton energy range 6-25 MeV were analyzed. These are the old experimental data, however, re-analysis of these data reveals very interesting peculiarities which never have been discussed before. The high energetic part of neutron spectrum due to the direct mechanism changes considerably from one isotope to other. This difference was described with incorporation of two components which provide the ＂broad bump＂, or ＂step like＂ shape of neutron spectra at high energy. The properties of these components are： different shape, energy shift between them, and very strong fluctuation between different isotopes for ratio of cross sections connected with partial contribution. One may conclude that shape of non-compound neutron spectrum demonstrates very strong （N-Z） odd-even effect. The direct comparison of experimental data, and semi-empirical results with （p,n） spectra predicted by the EMPIRE code, gave evidence that the traditional approach cannot predict this effect. New finding may explain the ＂constant temperature＂ dependence for level density in mass range A-60 discussed in several investigations. These new experimental peculiarities were demonstrated, and it may be considered as reality. At the same time there is not consequent physical model for their explanation. The fact that spectrum shape is correlated with N-Z value may give a hint that discussed effects are connected with ＂halo-neutrons＂.
基金supported by the National Key Research and Development Program of China(2017YFA0207002)the National Natural Science Foundation of China(21577032,21607042)+1 种基金the Fundamental Research Funds for the Central Universities(2018ZD11,2018MS114,and 2016MS02)the Jiangsu Provincial Key Laboratory of Radiation Medicine and Protection and the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘With the widespread application of radionuclide ^235U（VI）, it is inevitable that part of U（VI） is released into the natural environment. The potential toxicity and irreversibility impact on the natural environment has become one of the most forefront pollution problems in nuclear energy utilization. In this work, rod-like metal-organic framework （MOF-5） nanomaterial was synthesized by a solvothermal method and applied to efficiently adsorb U（VI） from aqueous solutions. The batch experimental results showed that the sorp- tion of U（Vl） on MOF-5 was strongly dependent on pH and independent of ionic strength, indicating that the dominant interaction mechanism was inner-sphere surface complexation and electrostatic interac- tion. The maximum sorption capacity of U（Vl） on MOF-5 was 237.0 mg]g at pH 5.0 and T = 298 K, and the sorption equilibrium reached within 5 rain. The thermodynamic parameters indicated that the removal of U（VI） on MOF-5 was a spontaneous and endothermic process. Additionally, the FT-IR and XPS analyses implied that the high sorption capacity of U（Vl） on MOF-5 was mainly attributed to the abundant oxygen-containing functional groups （i.e., C-O and C=O）. Such a facile preparation method and efficient removal performance highlighted the application of MOF-5 as a candidate for rapid and efficient radionuclide contamination＇s elimination in practical applications.
