[en] Through the experiment on test condition, a new method was established to detect the uranium in the liquor of acid leaching for uranium ores by portable radon counter. The application ideal was proposed to detect uranium in field geologic work, and to develop the on-line monitoring system for uranium milling. (authors)

[en] Uncertainty evaluation on the criteria of 'ferrous sulfate deoxidization/ammonium vanadate oxidation titrimetry to measure uranium' (EJ 267.2-84) issued by Ministry of Nuclear Industry was analyzed. The uncertainty brought by the method itself was obtained through the identification of uncertainty sources, quantification of uncertainty components and determination of uranium content by titration with calibrated ammonium vanadate solution. With the analytical study to uncertainty sources of entire process and components, and the application of statistical treatment based on scientific data, the combined standard uncertainty and expanded uncertainty about different levels of uranium content was reported. (authors)

[en] In this paper, the hot deformation behavior of Ti22Al25Nb was investigated by hot compression over a range of temperatures (950-1050 °C) and strain rates (0.001-1 s⁻¹). Considering the adiabatic heating and friction, the original curves were corrected. The friction-corrected data were lower than the measured flow stress data. The flow stress data increased after the temperature correction owing to the elimination of the softening effect. In addition, the work hardening effects on the hot deformation of the normal and multi-peak flow stress curves were compared. A critical dislocation density was proposed to analyze the multi-peak phenomenon. When the dislocation density decreased to a critical value, the work hardening and dynamic recrystallization mechanisms reached a balance. Then, a new work hardening mechanism became dominant, and the flow stress increased. The effect of second-phase particles on the hot deformation mechanisms was investigated. The result showed that second-phase particles led to a high nucleation rate and a low growth rate of new recrystallization grains during the rapid hot deformation.

[en] Radiation environment impact assessment is an important part of the environment assessment. According to the characteristics of tunnel construction, taking a tunnel project of the Northern Guangdong as an example, the radiation environment forecast and its impact assessment were studied, building the radiation environment prediction model, predicting the γ radiation dose rate of the tunnel and the amount of radon in the tunnel, estimating the diffusion of radon in air by air model, discussing the influence of the tunnel project on the radiation exposure of the surrounding public and construction workers basing on the estimated radiation dose. The radiation environment management could be strengthened. The additional radiation dose of environment and construction workers could be minimized, especially in the uranium-rich Northern Guangdong. (authors)

[en] We report the synthesis of sphere-like α-Ni(OH)₂ nanoarchitecture by self-assembly with the aid of hexamethylenetetramine (HMT). The α-Ni(OH)₂ nanoarchitectures, with a diameter of several micrometres, are composed of many nanoflakelets about 10 nm in thickness. The influences of the reaction temperature, time, reagent, nickel salt and pH value on the morphology and structure of the α-Ni(OH)₂ were studied, the chemical and thermal stability are discussed, and the formation mechanism is proposed. The α-Ni(OH)₂ nanoarchitectures display a good electrochemical capacity

[en] PM_2.5 aerosols from Jinan (36°256′N, 117°106′E) in the North China Plain region were investigated for water-soluble organic acids (WSOAs, i.e., oxalic acid, formic acid, acetic acid, methanesulfonic acid (MSA), and lactic acid) during 30 December 2016 to 21 February 2017. The average PM_2.5 concentration was 168.77 μg/m³ with about 90.74% samples beyond the National Ambient Air Quality (NAAQ) standards (Grade II). The total concentration of the measured WSOAs averaged at 1.34 μg/m³, contributing to 0.80% of PM_2.5 mass. In the observation, acetic acid was the most abundant WSOA, followed by oxalic acid, lactic acid, formic acid, and MSA. During the period, serious haze events frequently happened. The average concentrations of PM_2.5 and every WSOA species were higher in haze than those in non-haze. The correlations among species suggested that WSOAs in haze had complicated sources and secondary pathways, especially aqueous-phase reactions which played an important role on WSOAs. The concentrations of WSOAs declined in the Spring Festival compared with those in the non-Spring Festival due to holiday effect. Fireworks burning during the Spring Festival had different influences on WSOAs with slight increases for acetic acid and lactic acid. Five source factors were identified by positive matrix factorization (PMF) model for five WSOAs, respectively, and the results revealed that secondary reactions were the main sources of WSOAs in haze.

[en] Highlights: • The constitutive model was developed in the form of the hyperbolic sine. • The effects of deformation parameters on spheroidization mechanism were discussed. • The power dissipation map and instability map were constructed at the strain of 0.6. • The optimal processing parameters of Ti-5331 alloy were given. - Abstract: Ti-5331 titanium alloy, a new near α titanium alloy, as a candidate material for pressure hull of fusion reactor was studied in details in this paper. Firstly, the flow behavior was analyzed by stress-strain curves obtained by isothermal compression of Ti-5331 alloy, and the constitutive model was developed in the form of the hyperbolic sine. Secondly, the effects of deformation parameters on spheroidization mechanism were discussed. Finally, based on the dynamic materials model and instability criterion, the power dissipation map and instability map were constructed at the strain of 0.6, the obtained optimal processing parameters of Ti-5331 alloy were 750°C/0.001–0.01 s⁻¹ and 850–900 °C/0.01–0.1 s⁻¹ with the peak efficiencies of 65% and 73% respectively, which were further verified by the plate rolling test of Ti-5331 alloy.

[en] Flower-like Ni(OH)₂ nanoarchitectures have been synthesized through a one-step mild hydrothermal reaction with the aid of ethylenediamine in NiCl₂ aqueous solution. The flower with the size of several micrometers in diameter is composed of the ultra-thin nanosheets of several nanometers in thickness. It was found the ethylenediamine is vital to the formation of the flower-like nanoarchitectures. The influence of the concentration of the ethylenediamine and the reaction temperature on the formation of the flowers was analyzed and the formation mechanism of the flowers was proposed. Such flower-like β-Ni(OH)₂ nanoarchitectures will find potential applications in the fields, such as electrode, or will be used as a starting material to produce NiO, which is widely used in the magnetic, catalysts, sensor and electrochromic devices. - Graphical abstract: Flower-like Ni(OH)₂ nanoarchitectures were synthesized by a one-step mild hydrothermal reaction with the aid of ethylenediamine in NiCl₂ aqueous solution. The flower with the size of several micrometers in diameter is composed of the ultra-thin nanosheets of several nanometers in thickness. The flowers could be in catalysts, sensor and electrochromic devices, and alkaline rechargeable batteries

[en] Highlights: • V_2O_5 nanorods and their assemblies were synthesized by microwave way. • Electrochemical performance in Li-ion batteries was studied. • CV has revealed reversible redox behavior with charge–discharge cycling. • V_2O_5 nanorods assemblies show superior initial discharge capacity. • Low polarization of charge transfer reaction determines the enhanced capacity. - Abstract: Vanadium pentoxide nanorods assemblies were synthesized by a microwave-assisted hydrothermal synthesis, combined with subsequently annealing treatment. The structure and morphology of the nanorods were characterized by XRD, FESEM and HRTEM, and the electrochemical properties of the electrodes made from the V_2O_5 nanorods were investigated. The V_2O_5 nanorods with an average diameter of 100 nm and lengths up to several micrometers are almost parallel distributed in the assemblies. The V_2O_5 nanorods assemblies exhibit an initial discharge capacity of 330 mAh g"−"1 at a current density of 50 mA g"−"1, which is very higher than that of the separated V_2O_5 nanorods. The V_2O_5 nanorods assemblies also show a lower capacity fading rate in comparison with the separated V_2O_5 nanorods. A low polarization of the charge transfer reaction and a high diffusion rate of lithium ion inside the electrode composed of the paralleled nanorods are considered responsible for the enhanced capacity.

[en] Highlights: • Synthesize Lead sulfide (PbS) by chemical bath deposition method. • Drude-smith and Drude-Lorenz models were used to reproduce the complex conductivities extracted from the Terahertz spectrum. • The contribution of local free carriers to Terahertz conductivity is demonstrated in PbS. • Auger recombination was revealed by the optical pump-Terahertz probe technique. -- Abstract: The dynamics of carrier relaxation and charge transport of photoinduced carriers in Lead Sulfide nanocrystals with quantum confinement, synthesized by chemical bath deposition method, have been simultaneously determined using time-resolved terahertz spectroscopy with sub-picosecond time resolution. We use both Drude-Smith and Drude Lorenz model to successfully reproduce the photoconductivity spectra, which manifest that localized free-carriers not bounded excitons are responsible to the THz transport in PbS nanocrystals. The pump fluence dependence of carrier dynamics reveals the process of Auger recombination through the interaction between free carriers and excitons.