[en] The methods and results of the investigation on natural penetrating radiation level in the Tibet Autonomous Region are presented. 189 50 km x 50 km-grid measuring points were set uniformly up all over the region, with 136 densely measuring points of different types added. The results show that: (1) The point-weighted, area-weighted and population-weighted average value of natural γ radiation dose rate for field is 82.0, 78.0 and 84.2 nGy · h^-1, respectively; (2) The point-weighted average value of natural γ radiation dose rate for road is 83.3 nGy · h^-1; (3) The point-weighted and population-weighted average value of natural γ radiation dose rate inside buildings is 118.2 and 118.7 nGy·h^-1, respectively; (4)The point-weighted and population-weighted average value of the dose rate inside buildings from cosmic ray is 102.9 and 96.6 nGy·h^-1, and outside buildings is 121.4 and 112.1 nGy·h^-1, respectively; (5)The point-weighted and population-weighted average value of natural penetrating radiation dose rate inside buildings is 221.2 and 215.3 nGy·h^-1, outside buildings is 203.4 and 196.3 nGy·h^-1, respectively; (6)The annual effective dose equivalent from cosmic ray, natural γ radiation and natural penetrating radiation is 0.88, 0.67 and 1.55 mSv, respectively; and correspondingly, the annual collective effective dose equivalent is 0.18, 0.13 and 0.31 x 10⁴ man·Sv, respectively

[en] The basic theory of break-in-slope method in calculating the profile of auxiliary heating power deposition is presented. Using this method,the profile of ECRH power deposition is carried out by analyzing electron temperature and density at the time of ECRH injection on HL-2A for the first time. The applicability of this method is proved. (authors)

[en] Pd_77.5Cu₆Si_16.5 (at.%) bulk metallic glass with a diameter up to 11 mm was successfully fabricated by water quenching method together with melt purification. By using x-ray diffraction and transmission electron microscopy techniques, the structure of the as-prepared sample is confirmed to be glassy. The resulted sample with 11 mm diameter indicates that the melt purification by fluxing method can effectively enhance the glass forming ability of Pd-Cu-Si alloy, and increase its critical size of glassy sample. (condensed matter: structure, mechanical and thermal properties)

[en] We prepare Pd_40.5Ni_40.5P₁₉ glassy samples with purified ingots by copper mold casting at a high cooling rate and by water quenching at a low cooling rate. Both of them exhibit different supercooled liquid regions and multiple glass transition characteristics in their differential scanning calorimetric curves. The plasticity of the glassy sample prepared by copper mold casting is about 5% while that prepared by water quenching is almost zero (0.2%), indicating that cooling rate has influenced the plasticity of glassy alloys. By using high resolution TEM image analysis, it is revealed that there exist characteristic regions with different contrasts in the full glassy samples. The characteristic size is about 20–40 nm for the glassy sample prepared by water quenching and 2–4 nm for the one prepared by copper mold casting. The large difference in the plasticity of the glassy samples prepared by different cooling rates is believed to be related to the difference in the size of the characteristic nanoscale structures. The results indicate that adjusting cooling rate in preparation of glassy samples could modify the thermal and mechanical properties of the glassy alloys. (condensed matter: structure, mechanical and thermal properties)

[en] The investigation results of natural radioactivity level in river, lake, spring, well and tap water in the Tibet Autonomous Region is reported. There were totally 46 samples collected from 53 measuring points. The results show that the radioactivity level of water bodies of the Tibet Autonomous region was within normal natural background

[en] Upper and lower graphite divertor in EAST tokamak have been updated to tungsten divertors in 2014 and 2021 respectively to investigate the tungsten divertor operation and to realize high-performance long pulse discharge. Therefore, studies on the tungsten behavior are crucially important for improving the plasma performance. For the purpose four fast-time-response and four space-resolved extreme ultraviolet (EUV) spectrometers have been installed on EAST to observe line emissions from tungsten ions and their intensity radial profiles in wavelength ranges of 5 − 520 Å.

[en] Maximum likelihood method to process the data of HL-2A Thomson scattering system is presented. Using mathematical statistics, this method maximizes the possibility of the likeness between the theoretical data and the observed data, so that we could get more accurate result. It has been proved to be applicable in comparison with that of the ratios method, and some of the drawbacks in ratios method do not exist in this new one. (authors)

[en] Negative ions homologous to N⁻ are interesting systems, since there are several bound terms within the ground configuration. The forbidden transitions between them, often dominated by the magnetic dipole contributions, are affected by term mixing—a relativistic effect. When increasing the nuclear charge in the homologous sequence of negative ions, this effect increases. In this paper we use systematic multiconfiguration Dirac–Hartree–Fock calculations to study these effects and predict affinities, level splittings and transition rates between bound states of N⁻, P⁻, As⁻, Sb⁻ and Bi⁻. By monitoring the line strengths we are able to predict the deviation from the non-relativistic LS-coupled values for transitions between levels of the lowest ³P term. For Sb⁻ the ¹D term is also bound, and the prediction for the rates of its transition to the ³P-levels is a challenge for theory. For Bi⁻ less is known experimentally and we analyze its structure and the relativistic contributions to it. (paper)

[en] Based on the multi-configuration Dirac–Hartree–Fock method and using the GRASPVU package, a theoretical investigation was performed to study the lifetimes of hyperfine levels of the first excited level 3d⁹4s ³D₃ in Ni-like ions (Z = 72–79) for all stable isotopes with nuclear spin. Comparisons between hyperfine-induced electric quadrupole transition rates and the pure magnetic octupole transition rates show that the extra electric quadrupole transition channel caused by the nuclear magnetic dipole and electric quadrupole hyperfine interaction is important for most hyperfine levels in each individual ion. Lifetimes of most hyperfine levels are sensitive to this extra decay channel. Extreme cases are found in ¹⁸¹Ta, ¹⁸⁵Re and ¹⁸⁷Re, where lifetimes of some hyperfine levels are shortened by more than an order of magnitude. (paper)

[en] In this paper we propose an efficient off-axis multi-pass Nd:glass amplifier with a birefringence crystal. By utilizing the optical principle of birefringence crystals and the angle differences of the input–output laser directions in a typical off-axis amplifier, the amplification-pass was extended from four-pass to eight-pass without increasing the off-axis angle. The detailed principles and amplifier parameter design are presented. Using the proposed off-axis eight-pass amplifier, a 1 Hz repetitive Nd:glass amplifier at several joules was experimentally demonstrated. A total transmission of 54% was achieved. At an input energy of 1.5 mJ and small-signal gain of 3.6, the output energy and the corresponding net gain were 2.5 J and 1667, respectively. The beam quality was good. The spatial intensity modulation index for 90% beam aperture was 1.29 and the 95% energy concentration of far field patterns was 2.77 times the diffraction limit. (paper)