[en] Radionuclide contaminated soil adhered to plant surfaces can contribute to human ingestion dose. To determine this contribution, a method of ⁴⁶Sc neutron activation analysis was established and tested, by which a detection limit of 0.05 mg soil per g dry plant biomass can be obtained. In the field and greenhouse experiment the mass loading of soil on ryegrass (Lolium perenne L.) and broadbean (Vicia faba L.) was investigated and the contribution from rainsplash and wind erosion were evaluated separately. Soil retained on plant surfaces in field conditions in Seibersdorf/Austria was 5.77 ± 1.44 mg soil per g dry plant for ryegrass and 9.51 ± 0.73 mg soil per g dry plant for broadbean. Estimates of contribution from rainsplash and wind erosion to soil contamination of plants during the experimental period are 68 % and 32 % for broadbean 47 % and 53 % for ryegrass respectively. Mass loading results from field studies indicate that soil adhesion on plant surfaces can contribute up to 23 % of plant ¹³⁷Cs contamination, the transfer factors modified by mass loading decline differently, depending on ¹³⁷Cs concentration of the soil and the soil mass adhered to plant surfaces. (author)

[en] We consider two two-level atoms, which are located in two independent dissipative cavities. The two atoms are initially prepared in the singlet state vertical barΨ^-> - 1/√2 (vertical bar eg> - vertical bar ge>). We investigate the influence of dissipation on the entanglement between the two atoms. In the case of resonance the degree of the entanglement can fall abruptly to zero, which is the so-called sudden death of entanglement. It is noted that when two atoms are in a common environment, the singlet state is a decoherence-free state. When the dispersive limit is fulfilled, the degree of entanglement between the two atoms is oscillating at first, then it arrives at a steady value, which increases with the increase of the damping constant κ; when both fields are initially in the vacuum state, the entanglement between the two atoms will not decay

[en] Oxidation experiments associated with ion cyclotron resonance discharges (O-ICR) have been performed in HT-7 in the presence of a permanent magnetic field of 1.5-2.0 T. The influence of ICRH power and filling pressure on hydrogen and carbon removal rates was analysed. Total numbers of 5.70 x 10²² H-atoms, 1.6 x 10²² D-atoms and 2.35 x 10²² C-atoms had been removed within eight O-ICR cleanings. An ∼20.5 nm co-deposited film on average was removed from the limiters and liners with an area of 12 m². About 1.73 x 10²² O-atom retention in an O-ICR experiment corresponds to a coverage of 1.44 x 10¹⁶ O cm^-2. The highest removal rates of H, D and C-atoms of up to 2.64 x 10²² atoms h^-1, 7.76 x 10²¹ atoms h^-1 and 1.49 x 10²² atoms h^-1, respectively, were obtained in a 40 kW, 9 x 10^-2 Pa O-ICR cleaning, corresponding to a removal rate of co-deposits of about 317 nm/day (7.2 g/day for carbon). In a 50 min He-ICR cleaning after the O-ICR experiment about 5.39 x 10²¹ oxygen retention was removed. Also the influence of the oxidation experiment on the subsequent plasma operation was studied. Normal plasma discharges could be recovered after a few hours of disruptive plasma discharges

[en] Research on HT-7 tokamak focuses on exploiting the IBW-heated plasmas mainly to understand heating, active control of profiles and the synergetic interaction with LHCD. Both on-axis and off-axis electron heating with global peaked and localize steep electron pressure profile were realized. The operation of IBW and LHCD synergetic discharges were obtained and optimized through moving the IBW resonant layer to maximize the plasma performance and to avoid MHD activity. Experimental Advanced Superconducting Tokamak (EAST) has been built to perform advanced tokamak research in high performance regime and to explore methods for achieving a steady-state operation for a tokamak fusion reactor at ASIPP. This talk reports an overview of ICRF wall conditioning in HT-7 and EAST during recent campaigns.

[en] The magnetic domain structure of undercooled Fe₈₁Ga₁₉ alloys has been found to be very sensitive to the variation of undercooling during the solidification process. With increasing degree of undercooling, the evolution of domain patterns, magnetic contrast and the degree of the orientation was investigated which is relative to the magnetostriction. The combination of x-ray diffraction and magnetic force microscopy analyses has been shown to add new insights into the nature of the enhancement of magnetostriction in Fe₈₁Ga₁₉ alloys.

[en] Oxidation experiments by ion cyclotron resonance discharge in a gas mix of oxygen and helium (He/O-ICR) have been performed in a HT-7 in the presence of a permanent magnetic field of 1.5-2.0 T at wall temperatures of 400 to 470 K. Two kinds of gas mixture ratios of 4 : 1 and 1 : 1 (helium to oxygen) were used. With the same filling rate of oxygen, a higher pressure of He in the He/O-ICR plasma is beneficial for removal of co-deposition and reduces oxygen retention. For the same filling pressure, both the oxygen retention rate and the removal rate of H and C atoms during the He/O-ICR experiment were lower than that in the pure O-ICR experiment. The influence of ICR power and filling pressure on hydrogen and carbon removal rates was analysed. The highest removal rates of H and C atoms up to 5.4 x 10²¹ atoms/h and 7.2 x 10²¹ atoms/h, respectively, were obtained in 40 kW He/O-ICR cleaning with a ratio of He/O of 4 : 1 at 9.8 x 10^-2 Pa. By He-ICR cleanings and baking in helium gas, most oxygen retained on the wall was sufficiently removed before the subsequent plasma discharge. High power and high pressure He-ICRF cleanings are effective in removing the oxygen retained in the walls. Plasma discharges could be recovered after a few tens of disruptive plasma discharges

[en] Large-scale calculations have been performed using the GRASP2K package to accurately determine the lifetime of levels in 2p⁵3s configuration of neutral neon. In particular, we calculated the hyperfine-induced transition rates from two metastable levels ³P₂⁰,₀ to the ground state for odd Ne isotopes. It was found that hyperfine interactions drastically quench the lifetime of these two levels.

[en] When the effects of the finite mass of the nucleus and the spatial nuclear charge distribution are taken into account in the Hamiltonian describing an atomic system, the isotopes of an element have different electronic energy levels. In the present work, we are investigating these mass and field effects in neutral barium, hoping to shed some light on the surprising observed deviation of isotope shifts from their expected behavior for odd isotopes in an analysis based on King-plots.

[en] We prove that the Hartree–Fock (HF) basis provides good convergences for many-body perturbation calculations with renormalized realistic nuclear forces. Two types of ab initio perturbation calculations of effective interactions have been performed in the HF basis instead of the harmonic oscillator basis. One is called the Brillouin–Wigner (BW) perturbation and another is the Rayleigh–Schrödinger (RS) perturbation. The results show that ab initio perturbation calculations within the HF basis have comparably good convergences as the nonperturbative in-medium similarity renormalization group. In the HF basis some types of perturbation diagrams can be cancelled out, while the cancellation does not happen in the harmonic oscillator basis. We have investigated the sd shell with the chiral N³LO potential softened by $V_{\mathrm{l}\mathrm{o}\mathrm{w}-<!--\; ???\; -->k}$. With the low-momentum N³LO potential, we first perform the spherical HF calculation for the ¹⁶O core, and use the perturbations to derive the sd-shelleffective two-body interactions in the HF basis. The calculations give simultaneously single-particle energies and excitation spectra of two-valence-particle systems (i.e. ¹⁸O, ¹⁸F, and ¹⁸Ne in the sd shell). Convergences have been analyzed order by order. We find that the HF RS perturbation gives even better results than the HF BW approximation. The HF  effective interactions derived by the perturbations can be used for further many-body calculations. (paper)

[en] The close correlation between the edge electrostatic fluctuations around the last closed flux surface and the magnetohydrodynamic (MHD) activity in the case of lower hybrid current drive (LHCD) is observed and analysed in the HT-7 tokamak. The turbulent transport is primarily driven by a coherent MHD mode, indicating that the electrostatic fluctuations are strongly correlated with MHD activity. The results supply direct evidence that the edge electrostatic fluctuations in tokamak plasmas can be decreased by suppressing internal tearing mode activity and thus reduce the radial plasma transport. The coherent electrostatic fluctuations may be possibly attributable to the radial plasma transport accompanied by the internal tearing mode activity. Studies show that the smaller electrostatic fluctuations at a frequency of 10 kHz may be mainly ascribed to the suppressed MHD activity, possibly due to the formation of an internal transport barrier and flow shear in the edge region. It is speculated that the change of mode region resulting from the mode coupling/transform, excited by the modified current profile by LHCD, could also provide some contribution to the MHD reduction