[en] Short communication. 1 ref

[en] Partial melting technique consists of peritectic melting and solidification of Bi-2212 phase. This technique has been applied in two temperature ranges of the Ca poor part of the Bi_2.20Sr_3-yCa_yCu₂O_8+Δ system phase diagram, both involving multi-phase regions, with the aim of preparing bulk and dense Bi-2212 phase. Microstructural and intrinsic physical parameters which could act as potential suppression mechanisms of the electric transport properties of bulk Bi-2212 have been discussed

[en] The thermodynamic properties, including activity coefficients, osmotic coefficients and excess Gibbs free energy for RbCl and Rb₂SO₄ aqueous mixtures at T=298.15 K and in 0.01 mol · kg^-1 to 5 mol · kg^-1 ionic strength, were determined by emf measurements. The Rb-ISE and Ag-AgCl electrodes used in this work were prepared in our laboratory and had a reasonably good Nernst response. The experimental data were fitted by using the Harned rule and Pitzer model. The Harned coefficients and the Pitzer binary and ternary interaction parameters for the system have been evaluated. The experimental results obey the Harned rule. The Pitzer model can be used to describe this aqueous system satisfactorily

[en] Ribbons of the Fe₅₃Nd₃₇Al₁₀ alloy with different rolling rates were prepared by the melt spinning method. The magnetic properties, phase composition and microstructure of the ribbons were systematically investigated by vibrating sample magnetometer (VSM), differential scanning calorimeter (DSC), X-ray diffraction (XRD), scanning electron microscope (SEM), focused ion beam (FIB) and high resolution transmission electron microscope (HRTEM). The micrograph shows that the ribbon melt-spun at 5 m s⁻¹ is composed of Nd₂Fe₁₇ phase with approximately 5 μm in size and some clusters of 5 nm in diameter in the amorphous matrix, while no obviously crystallized phase is detected in the sample melt-spun at 20 m s⁻¹. Both of the ribbons melt-spun at 5 m s⁻¹ and 20 m s⁻¹ show hard magnetic properties at room temperature, but they exhibit different magnetic properties at low temperature. The hard magnetic property of the ribbon melt-spun at 5 m s⁻¹ would be due to the exchange coupling interactions and pinning effect. However, the magnetism of the sample melt-spun at 20 m s⁻¹ would be contributed to the pinning effect.

[en] A continuum dislocation dynamics model capable of capturing the cellular arrangements of dislocations in deformed crystals is presented. A small strain formulation of the model is given, followed by sample results of stress-strain behaviour, dislocation density evolution, dislocation cell pattern, lattice rotation, and geometrically necessary dislocation density and strain energy density distributions. An important finding of the current work is that dislocations form patterns under all circumstances due to their long range interactions. It is found, however, that the famous cell structure pattern forms when cross slip is activated. It is also found that cells are 3D sub-regions surrounded by dislocations walls in all directions, and they form, disappear, and reappear as a result of the motion of cell walls and formation of new walls by cross slip. It is further found that the average cell size is connected with the applied resolved shear stress according to the similitude principle observed in related experiments. The importance of these results is briefly discussed in the context of recrystallization. (paper)

[en] Short communication

[en] The details of the double-crystal monochromator and its control system of the first monochromatic photon beam line for EXAFS studies 4W1B at Beijing Synchrotron Radiation Laboratory are described in this paper, the commissioning and the first experimental results obtained are also presented

[en] The design and test of the focused x-ray beam line 4W1C for general purpose diffraction study at the Synchrotron Radiation Laboratory of the Institute of High Energy Physics is reported

[en] Variation trends across the AnO₂ series of An5f-electron covalent bonding and An5f→O3s, O2p→An5f charge transfer energies, are studied using DV-Xα relativistic spin-polarised computation of electronic structures applied to 11 'AnO₈' clusters, from ThO₈ to FmO₈. It is found that the binding energies of 5f orbitals, therefore the An5f-O2p hybridisation, are increasing though the 5f orbitals are localising across the An series. In our calculations, the 3s and 3p ionic-like orbitals of O^2- ions are included for the first time as LCAO-MO bases. Then, the conduction band is a mixing of O3s and An6d and its lower edge corresponds to an O3s-dominated state. Moreover, the calculated charge transfer (CT) energies of An5f→O3s and O2p→An5f transitions show the so-called tetrad effect when CT energies, respectively increasing and decreasing across the AnO₂ series. It is pointed out that the tetrad effect here comes mainly from the special spin-polarised pattern of 5f levels and the increasing general trend of 5f binding energies. (orig.)

[en] Full function integrated, compact silicon photodiode based solid state neutral particle analyzers (ssNPA) have been developed for energetic particle (EP) relevant studies on the Experimental Advanced Superconducting Tokamak (EAST). The ssNPAs will be mostly operated in advanced current mode with a few channels to be operated in conventional pulse-counting mode, aiming to simultaneously achieve individually proved ultra-fast temporal, spatial, and spectral resolution capabilities. The design details together with considerations on EAST specific engineering realities and physics requirements are presented. The system, including a group of single detectors on two vertical ports and two 16-channel arrays on a horizontal port, can provide both active and passive charge exchange measurements. ssNPA detectors, with variable thickness of ultra thin tungsten dominated foils directly deposited on the front surface, are specially fabricated and utilized to achieve about 22 keV energy resolution for deuterium particle detection