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[en] Total-Reflection X-ray Fluorescence spectrometry (TRXF) is known for its high sensitivity down to Pg-level or sub ppb level, respectively. Therefore the spectrometry is considered as a most competitive tool in the application of trace element analysis. The technique of TRXF was investigated in the laboratory. But small isotope X-γ source is chosen as an exciting source instead of general X-ray tube. From the primitive experiment the conclusion proved that the condition of total reflection can be built and the analysis sensitivity of TRXF is higher than that of normal x-ray analysis

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[en] In the three wastes treatment of Hongyanhe nuclear power, the blowing type level gauge is devoted to the process drains tanks. But the level meter usually displays drift data. The paper analyses the reasons by the mechanical model and the simple formula, and draw the main conclusion: the scavenge pipe is clogged by precipitated borax. (author)

[en] Single-crystalline wurtzite GaN nanotubes have been synthesized recently with proposed applications in nanoscale electronics, optoelectronics and the biochemical-sensing field. Molecular dynamics methods with a Stillinger-Weber potential are used to investigate the melting behavior, thermal conductivity and mechanical properties of these wurtzite-type single crystalline GaN nanotubes. Four major topical areas are summarized in this chapter. (1) The melting temperature of the GaN nanotubes increases with the thickness of the nanotubes to a saturation value, which is close to the melting temperature of bulk GaN. The simulations result reveal that the nanotubes begin to melt at the surface, and then the melting rapidly extends to the interior of the nanotubes as the temperature increases. (2) The thermal conductivity of nanotubes is smaller than that of the bulk GaN single crystal. The thermal conductivity is also found to decrease with temperature and increase with increasing wall thickness of the nanotubes. The change of phonon spectrum and surface inelastic scattering may account for the reduction of thermal conductivity in the nanotubes, while thermal softening and high frequency phonon interactions at high temperatures may provide an explanation for its decrease with increasing temperature. (3) At low temperatures, the simulation results show that the nanotubes exhibit brittle properties; whereas at high temperatures, they behave as ductile materials. The brittle to ductile transition temperature generally increases with increasing wall thickness of the nanotubes and increasing strain rate. (4) The simulation temperature, tube length and strain rate affect the buckling behavior of GaN nanotubes. The critical stress decreases with the increase of simulation temperature and tube length. The dependence of buckling on tube length is consistent with the analysis of equivalent continuum structures using Euler buckling theory