We study contributions of the pion meson and spatial component of the omega meson in the odd-A carbon isotopes. The pion and spatial omega provide small attractions in odd-A nuclei, giving rise to considerable influen...We study contributions of the pion meson and spatial component of the omega meson in the odd-A carbon isotopes. The pion and spatial omega provide small attractions in odd-A nuclei, giving rise to considerable influences on the single-particle energies rather than the bulk properties such as total binding energies, and root-mean-square (rms) radii. The ±? (spin) splittings, arising from the spatial omega, are large in <SUP>11</SUP>C and <SUP>13</SUP>C and drop as the isospin rises in odd-A carbon isotopes. As an isovector, the pion can shift slightly the relative potential depth of neutron and proton, contrary to the role of the rho meson. There is a general trend that both the pion and spatial omega fields reduce with the rise of isospin in the isotopic chain. From the normal nucleus to halo nucleus, an abnormal drop of the pion or spatial omega field may occur, as can be seen in <SUP>19</SUP>C, <SUP>15</SUP>C, and <SUP>21</SUP>C.展开更多
It reviewed results on low-energy nuclear reaction （LENR） processes in a high-voltage （1,000-4,000 V） electric discharge system. The experimental results are divided into three sets： excess heat measurements; yie...It reviewed results on low-energy nuclear reaction （LENR） processes in a high-voltage （1,000-4,000 V） electric discharge system. The experimental results are divided into three sets： excess heat measurements; yield of impurity nuclides （nuclear ash）; X-ray measurements. Up to 8 W of excess power was observed, with a power gain of up to 170% was seen in glow discharge experiments. Up to 300 W of excess power, with a power gain up to 340% was observed in experiments using a high-voltage electrolysis cell. The impurity nuclide yield showing a shift of up to a few per cent from natural isotopic abundances was detected by spark mass spectrometry, by secondary ionic mass spectrometry, and by secondary neutral mass spectrometry. X-ray emission in the range of 0.6-6.0 keV, has been observed. Based on these experimental results we propose a phenomenological model for LENR based on the interaction of an electric discharge with condensed matter （of the cathode）.展开更多
The feasibility of producing superheavy nuclei in proton evaporation channels was systematically studied within the dinuclear system(DNS)model.Due to the Z=114 proton-shell,one can synthesize Fl isotopes in proton eva...The feasibility of producing superheavy nuclei in proton evaporation channels was systematically studied within the dinuclear system(DNS)model.Due to the Z=114 proton-shell,one can synthesize Fl isotopes in proton evaporation channels.We only considered the case of evaporating one proton first and then n neutrons in this work,other cases were ignored due to the small cross-section.The production cross sections of unknown isotopes ^(290,291)Fl in ^(38)S+^(255)Es reaction are the highest compared with ^(50)Ti+^(243)Np and ^(54)Cr+^(239)Pa reactions,and the maximum cross sections are 1.1 and 15.1 pb,respectively.^(42)S+^(254)Es is a promising candidate to approach the island of stability as the radioactive beam facilities are upgraded in the future,and the production cross sections of ^(291−294)Fl in that reaction are estimated to be 3.2,6.0,4.0,and 0.1 pb,respectively.展开更多
The determination of the effective minimum detectable activity （MDA） of radionuclides by a detection system plays an im- portant role in environmental radiation monitoring. In this study, the responses of an NaI（TI...The determination of the effective minimum detectable activity （MDA） of radionuclides by a detection system plays an im- portant role in environmental radiation monitoring. In this study, the responses of an NaI（TI） airborne γ ray spectrometry （AGRS） system to different radionuclides （137Cs and 131I） were investigated using the Monte Carlo technique. The MDA values were determined under different conditions according to the counting spectra obtained from the Monte Carlo simulation. The equivalent mass thickness method was applied to the Monte Carlo modeling for monitoring ground radiation to reduce sta- tistical uncertainty. The secondary source method was used to monitor both air and ground radiation. A quadratic relationship was found between the MDA and activity concentration. An exponential relationship was found between the MDA and altitude The MDA of a specific radionuclide from external detectors was found to be superior to that obtained from internal detectors under the same conditions. The MDA values in an NaI（Tl） AGRS system under different conditions can be estimated based on the results of this study.展开更多
文摘We study contributions of the pion meson and spatial component of the omega meson in the odd-A carbon isotopes. The pion and spatial omega provide small attractions in odd-A nuclei, giving rise to considerable influences on the single-particle energies rather than the bulk properties such as total binding energies, and root-mean-square (rms) radii. The ±? (spin) splittings, arising from the spatial omega, are large in <SUP>11</SUP>C and <SUP>13</SUP>C and drop as the isospin rises in odd-A carbon isotopes. As an isovector, the pion can shift slightly the relative potential depth of neutron and proton, contrary to the role of the rho meson. There is a general trend that both the pion and spatial omega fields reduce with the rise of isospin in the isotopic chain. From the normal nucleus to halo nucleus, an abnormal drop of the pion or spatial omega field may occur, as can be seen in <SUP>19</SUP>C, <SUP>15</SUP>C, and <SUP>21</SUP>C.
文摘It reviewed results on low-energy nuclear reaction （LENR） processes in a high-voltage （1,000-4,000 V） electric discharge system. The experimental results are divided into three sets： excess heat measurements; yield of impurity nuclides （nuclear ash）; X-ray measurements. Up to 8 W of excess power was observed, with a power gain of up to 170% was seen in glow discharge experiments. Up to 300 W of excess power, with a power gain up to 340% was observed in experiments using a high-voltage electrolysis cell. The impurity nuclide yield showing a shift of up to a few per cent from natural isotopic abundances was detected by spark mass spectrometry, by secondary ionic mass spectrometry, and by secondary neutral mass spectrometry. X-ray emission in the range of 0.6-6.0 keV, has been observed. Based on these experimental results we propose a phenomenological model for LENR based on the interaction of an electric discharge with condensed matter （of the cathode）.
文摘The feasibility of producing superheavy nuclei in proton evaporation channels was systematically studied within the dinuclear system(DNS)model.Due to the Z=114 proton-shell,one can synthesize Fl isotopes in proton evaporation channels.We only considered the case of evaporating one proton first and then n neutrons in this work,other cases were ignored due to the small cross-section.The production cross sections of unknown isotopes ^(290,291)Fl in ^(38)S+^(255)Es reaction are the highest compared with ^(50)Ti+^(243)Np and ^(54)Cr+^(239)Pa reactions,and the maximum cross sections are 1.1 and 15.1 pb,respectively.^(42)S+^(254)Es is a promising candidate to approach the island of stability as the radioactive beam facilities are upgraded in the future,and the production cross sections of ^(291−294)Fl in that reaction are estimated to be 3.2,6.0,4.0,and 0.1 pb,respectively.
基金supported by the National Defense Basic Scientific Research Project(Grant No.B2520133077)National High-tech R&D Program of China("863"Program)(Grant No.2012AA061803)
文摘The determination of the effective minimum detectable activity （MDA） of radionuclides by a detection system plays an im- portant role in environmental radiation monitoring. In this study, the responses of an NaI（TI） airborne γ ray spectrometry （AGRS） system to different radionuclides （137Cs and 131I） were investigated using the Monte Carlo technique. The MDA values were determined under different conditions according to the counting spectra obtained from the Monte Carlo simulation. The equivalent mass thickness method was applied to the Monte Carlo modeling for monitoring ground radiation to reduce sta- tistical uncertainty. The secondary source method was used to monitor both air and ground radiation. A quadratic relationship was found between the MDA and activity concentration. An exponential relationship was found between the MDA and altitude The MDA of a specific radionuclide from external detectors was found to be superior to that obtained from internal detectors under the same conditions. The MDA values in an NaI（Tl） AGRS system under different conditions can be estimated based on the results of this study.
