[en] A carbon-free, three-dimensional network structured material composed of NiCo_2O_4 nanowires and Ni foam was synthesized by a facile method. When applied as the air electrode for the lithium–oxygen battery, the unique network structure enables the surface of nanowires highly accessible to the reactants and facilities the electron transport during the charge/discharge processes. A superior electrochemical performance including low charge overpotential and excellent cyclability are obtained. This work suggests the great potential of the carbon-free NiCo_2O_4@Ni as the air electrodes for lithium–oxygen batteries

[en] In this study, nano-TiO_2(B) coated LiMn_2O_4 was prepared via a two-step method, combining a hydrothermal method with electrostatic attraction. By adjusting the sintering time, porous and dense nano-TiO_2(B) coating structure were formed on the surface of LiMn_2O_4 particles. Electrochemical test results showed that 2 wt.% porous TiO_2(B) coated LiMn_2O_4 exhibited highest capacity retention at 77.4% after 300 cycles at 55 °C and the best rate capability. Inductively coupled plasma spectroscopy(ICP), charge and discharge curves and electrochemical impedance spectroscopy (EIS) results revealed that the improved electrochemical performances was due to the suppression of the undesired SEI film, as well as suppression of Mn dissolution at the cathode and reduced polarization

[en] Nitrogen-doped porous carbon nanofiber webs-sulfur composites (N-CNFWs/S) were synthesized for the first time with sulfur (S) encapsulated into nitrogen-doped porous carbon nanofiber webs (N-CNFWs) via a modified oxidative template route, carbonization-activation and thermal treatment. The composites were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET), X-ray powder diffraction (XRD), and thermogravimetry (TG) measurements. The results show that sulfur is well dispersed and immobilized homogeneously in the micropores of nitrogen-doped porous carbon nanofiber webs (N-CNFWs) with high electrical conductivity, surface area and large pore volume. The electrochemical tests show that the N-CNFWs/S composites with 60 wt. % of S have a high initial discharge capacity of 1564 mA h g⁻¹, a good cycling stability at the current density of 175 mA g⁻¹, and excellent rate capability (reversible discharging capacity of above 400 mA h g⁻¹ at 1600 mA g⁻¹)

[en] In order to further understand the current status of capacity building of national nuclear emergency medical rescue units, wehave established an evaluation index system and scoring standards, and evaluated a unit based at the Second Affiliated Hospital of Soochow University. The assessment focuses on 7 first-level indicators, including policies and regulations, organizational structures, contingency plans, command and control, emergency facilities and equipment, emergency response actions, as well astraining and drill. With the status quofound out and problems identified, suggestions have been made on the capacity building and assessment, such as rescue plans, material and equipment allocation and management, training and drill. (authors)

[en] Highly conductive polyaniline (PANI) membranes synthesized by a proton doping method are used as waterproof barriers for lithium air batteries. When the membrane is attached to the air cathode, it promotes lithium ion transport into the electrode and blocks the moisture entrance, which can protect the lithium anode from erosion. Electrolyte evaporation from the battery is also greatly reduced. Electrochemical tests show that lithium air cells with this design deliver a much higher specific capacity, 3241 mAh g⁻¹ (referring to carbon), under high relative humidity (RH > 20%) conditions; the cells also have an excellent rate capability.

[en] Highlights: • Solid-state electrolyte based on ionic liquid/polymer/ceramic composites for room temperature solid-state LMBs is fabricated. • The synergistic effect on the SEI formation with high content of LiF is unveiled by experimental and computational study. • The high ionic conductivity and excellent mechanical strength of the SSCE enable superior cyclical stability. All-solid-state electrolytes provide a guarantee for the safe running of Li metal batteries (LMBs) with high energy density. Nevertheless, the low ionic conductivity and huge interfacial impedance between lithium anodes and electrolytes are the critical issues baffling their rapid development and practical application, particularly limiting their operation at room temperature. The introduction of ionic liquids (IL) is expected to solve the above problems. However, the effect of the IL-involved solid-state electrolytes on lithium dendrites suppression has not been clearly revealed and still necessitates in-depth evaluation. In this article, we report an in situ LiF-rich solid-electrolyte interphase (SEI) on the lithium anode triggered by reductive decomposition of IL and Li_1.5Al_0.5Ge_1.5(PO₄)₃-involved electrolyte. For the first time, the mechanism of SEI formed on Li metal based on IL-based solid-state electrolyte was unveiled. A combination of experimental and computational investigation manifests that the presence of Li_1.5Al_0.5Ge_1.5(PO₄)₃ promotes the release of fluorine anion from IL, and a SEI layer with high content of LiF can be generated in situ through the reductive decomposition of wandering fluorine anion. Thanks to the high mechanical modulus from Li_1.5Al_0.5Ge_1.5(PO₄)₃, the symmetric LiLi batteries equipped with synthesized solid-state composite electrolyte (SSCE) exhibit extremely stable Li plating/stripping behavior for more than 2700 h with a small polarization voltage of 50 mV at 0.1 mA cm⁻². Moreover, the assembled solid-state LiLiFePO₄ batteries based on SSCE could operate steadily for 196 cycles at ambient temperature, with 90.7% capacity retention. These results provide a promising insight into the design of SSCE and realization of room temperature solid-state LMBs with high performance.

[en] The concentrations of natural radioisotopes ²³⁰Th and ²³²Th in Korean foods were measured by the method of calcium oxalate co-precipitation in addition to the conventional anion-exchange method and alpha spectroscopic measurement. The ²³⁰Th concentrations (mBq/kg-fresh) in Korean foods were found to be as follows: milk 0.14-2.45, pork 2.98-8.97, beef 1.94-9.80, chicken 1.22-13.0, rice 0.43-2.35, wheat 0.53-14.4, and soybeans, 8.44-91.6. The ²³²Th concentrations (mBq/kg-fresh) in Korean foods were found to be as follows: milk 0.01-2.46, pork 0.28-9.32, beef 1.02-5.34, chicken 0.56-4.98, rice 0.32-2.54, wheat 0.53-20.0, and soybeans, 2.30-42.2. The annual internal dose of Th was also estimated. The annual internal dose of ²³⁰Th and ²³²Th in milk was about 0.006 μSv/yr and much lower than that of other countries because of the low intake of milk in Korea compared to other countries. The annual internal dose of ²³⁰Th and ²³²Th in the rice was about 0.043 μSv/yr and highest because rice is the staple food of Koreans. (author)

[en] Transition metal nitrides (TMNs) are promising electrode materials for high-performance energy storage devices owing to their excellent conductivity, thermal stability, high theoretical capacity and excellent electrochemical activity. However, the structural instability present in the electrochemical reaction process significantly limits their widespread application. Herein, we present a V-Ni-based nitride heterojunction on carbon cloth (VN/Ni₃N-Ni/CC) as an active electrode material for flexible supercapacitors. The VN/Ni₃N-Ni/CC composite electrode was successfully fabricated through controllable nitridation of the corresponding vanadium-nickel oxide grown on carbon cloth (V-Ni-O/CC) precursors. The electrochemical results reveal that the areal capacitance of the VN/Ni₃N-Ni/CC based supercapacitor with a nitriding temperature of 400 C and a nitriding time of two hours can achieve a maximum areal capacitance of 845.63 mF cm^-2 at a current density of 0.5 mA cm^-2, and the electrode in the three-electrode system retains 86.1% of its initial capacitance value after 1500 cycles at a current density of 10 mA cm^-2. In addition, the assembled flexible all-solid-state symmetric supercapacitor using the VN/Ni₃N-Ni/CC electrode exhibits an areal capacitance ratio of 19.1 mF cm^-2 at a current density of 0.4 mA cm^-2 and excellent cycling stability. Moreover, it displays exceptional flexibility under different bending angles highlighting its potential for integration into flexible electronic devices. (authors)

[en] The concentrations of naturally occurring radioisotopes (²³²Th, ²²⁸Th, ²³⁰Th, ²²⁸Ra, ²²⁶Ra, and ⁴⁰K) in typical Korean foods were evaluated. The daily intakes of these radioisotopes were calculated by comparing concentrations in typical Korean foods and the daily consumption rates of these foods. Daily intakes were as follows: ²³²Th, 0.00-0.23; ²²⁸Th, 0.00-2.04; ²³⁰Th, 0.00-0.26; ²²⁸Ra, 0.02-2.73; ²²⁶Ra, 0.01-4.37 mBq/day; and ⁴⁰K, 0.01-5.71 Bq/day. The total daily intake of the naturally occurring radioisotopes measured in this study from food was 39.46 Bq/day. The total annual internal dose resulting from ingestion of radioisotopes in food was 109.83 μSv/y, and the radioisotope with the highest daily intake was ⁴⁰K. These values were same level compiled in other countries