Based on the density functional theory, we calculated the structures of the two main possible self-interstitial atoms（SIAs） as well as the migration energy of tungsten（W） atoms. It was found that the difference of...Based on the density functional theory, we calculated the structures of the two main possible self-interstitial atoms（SIAs） as well as the migration energy of tungsten（W） atoms. It was found that the difference of the 110 and 111 formation energies is 0.05–0.3 e V. Further analysis indicated that the stability of SIAs is closely related to the concentration of the defect. When the concentration of the point defect is high, 110 SIAs are more likely to exist, 111 SIAs are the opposite. In addition, the vacancy migration probability and self-recovery zones for these SIAs were researched by making a detailed comparison. The calculation provided a new viewpoint about the stability of point defects for selfinterstitial configurations and would benefit the understanding of the control mechanism of defect behavior for this novel fusion material.展开更多
The paper is a summary of Russian material studies performed in frames of activi-ties aiming at substantiation of safety of the International Thermonuclear Experimental Reactor(ITER)after 2001.Subthreshold sputtering ...The paper is a summary of Russian material studies performed in frames of activi-ties aiming at substantiation of safety of the International Thermonuclear Experimental Reactor(ITER)after 2001.Subthreshold sputtering of tungsten by 5 eV deuterons was revealed at temper-atures above 1150℃.Mechanism of globular films formation was further studied.Computations of tritium permeation into vacuum vessel coolant confirmed the acceptability of vacuum vessel cooling system for removal of the decay heat.The most dangerous accident with high-current are in toroidal superconducting magnets able to burn out a bore up to 0.6 m in diameter in the cryostat vessel was determined.Radiochemical reprocessing of V-Cr-Ti alloy and its purification from activation products down to a contact dose rate of~10μSv/h was developed.展开更多
This paper introduces the ceramic materials fusion method to use porcelain crucible instead of platinum crucible. By this method, not only the funds can be saved, but also the operation becomes simple and the analysed...This paper introduces the ceramic materials fusion method to use porcelain crucible instead of platinum crucible. By this method, not only the funds can be saved, but also the operation becomes simple and the analysed results are accurate and reliable. On the other hand, the high fusion point materials, such as high aluminum ceramic raw ma- terials, can also be melted and their aluminum contents can be determined by this method. Thus, it can be widely used in the students laboratory and routine analysis of small and middle industrial enterprises.展开更多
Recently, the work function （WF） changes in metallic and ceramic materials to be potentially used in future fusion reactors have been examined by means of Kelvin probe （KP）, under He ion irradiation in high energy...Recently, the work function （WF） changes in metallic and ceramic materials to be potentially used in future fusion reactors have been examined by means of Kelvin probe （KP）, under He ion irradiation in high energy （MeV） and / or low energy （500 eV） ranges. The results of polycrystalline Ni samples indicate that the 1 MeV beam only induces decrease in the WF within the experimental fluence range; whereas the irradiation of 500 eV beam results in decrease in the WF firstly, then increase till saturation. A dual layer surface model is employed to explain the observed phenomena, together with computer simulation results by SRIM code. Charges buildup on the surface of lithium ceramics has been found to greatly influence the probe output, which can be explained qualitatively using a model concerning an induction electric field due to external field and free charges on the ceramic surface.展开更多
基金Project supported by the Fundamental Research Funds for the Central Universities of Ministry of Education of China(Grant Nos.A0920502051411-5 and2682014ZT30)the Program of International Science and Technology Cooperation,China(Grant No.2013DFA51050)+6 种基金the National Magnetic Confinement Fusion Science Program,China(Grant Nos.2011GB112001 and 2013GB110001)the National High Technology Research and Development Program of China(Grant No.2014AA032701)the National Natural Science Foundation of China(Grant No.11405138)the Southwestern Institute of Physics Funds,Chinathe Western Superconducting Technologies Company Limited,Chinathe Qingmiao Plan of Southwest Jiaotong University,China(Grant No.A0920502051517-6)the China Postdoctoral Science Foundation(Grant No.2014M560813)
文摘Based on the density functional theory, we calculated the structures of the two main possible self-interstitial atoms（SIAs） as well as the migration energy of tungsten（W） atoms. It was found that the difference of the 110 and 111 formation energies is 0.05–0.3 e V. Further analysis indicated that the stability of SIAs is closely related to the concentration of the defect. When the concentration of the point defect is high, 110 SIAs are more likely to exist, 111 SIAs are the opposite. In addition, the vacancy migration probability and self-recovery zones for these SIAs were researched by making a detailed comparison. The calculation provided a new viewpoint about the stability of point defects for selfinterstitial configurations and would benefit the understanding of the control mechanism of defect behavior for this novel fusion material.
文摘The paper is a summary of Russian material studies performed in frames of activi-ties aiming at substantiation of safety of the International Thermonuclear Experimental Reactor(ITER)after 2001.Subthreshold sputtering of tungsten by 5 eV deuterons was revealed at temper-atures above 1150℃.Mechanism of globular films formation was further studied.Computations of tritium permeation into vacuum vessel coolant confirmed the acceptability of vacuum vessel cooling system for removal of the decay heat.The most dangerous accident with high-current are in toroidal superconducting magnets able to burn out a bore up to 0.6 m in diameter in the cryostat vessel was determined.Radiochemical reprocessing of V-Cr-Ti alloy and its purification from activation products down to a contact dose rate of~10μSv/h was developed.
文摘This paper introduces the ceramic materials fusion method to use porcelain crucible instead of platinum crucible. By this method, not only the funds can be saved, but also the operation becomes simple and the analysed results are accurate and reliable. On the other hand, the high fusion point materials, such as high aluminum ceramic raw ma- terials, can also be melted and their aluminum contents can be determined by this method. Thus, it can be widely used in the students laboratory and routine analysis of small and middle industrial enterprises.
文摘Recently, the work function （WF） changes in metallic and ceramic materials to be potentially used in future fusion reactors have been examined by means of Kelvin probe （KP）, under He ion irradiation in high energy （MeV） and / or low energy （500 eV） ranges. The results of polycrystalline Ni samples indicate that the 1 MeV beam only induces decrease in the WF within the experimental fluence range; whereas the irradiation of 500 eV beam results in decrease in the WF firstly, then increase till saturation. A dual layer surface model is employed to explain the observed phenomena, together with computer simulation results by SRIM code. Charges buildup on the surface of lithium ceramics has been found to greatly influence the probe output, which can be explained qualitatively using a model concerning an induction electric field due to external field and free charges on the ceramic surface.
