[en] Solid polymer electrolytes consisting of poly(propylene glycol) diacrylate and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) were deposited onto Cu_2O-coated 3D Cu nano-pillars through cathodic electropolymerization. Electropolymerization, using constant and pulsed current techniques, was used to produce polymer coatings directly onto 3D substrates with thicknesses down to nano-scale dimensions. SEM confirmed that pulsed current deposition is comparatively beneficial for producing uniform and conformal electrolyte coatings along the nano-pillar structure. ATR/FTIR studies of the electropolymerized electrolytes showed that the degree of polymerization in the electrolyte can be increased by a heating treatment after synthesis. XPS analysis confirmed the presence of co-deposited LiTFSI salt in the polymer layer during electropolymerization. The ionic conductivity of the obtained electrolytes was characterized by EIS and is in the order of 10"−"6 S cm"−"1 at room temperature. This work demonstrates that the electrolyte coated on the nano-pillar electrodes may serve as a template for further deposition of electrode materials for the assembly of 3D-microbattery whole-cells

[en] The effects of nano-TiO₂ and normal size TiO₂ additions on the microstructure and magnetic properties of manganese–zinc (Mn–Zn) power ferrites were investigated, respectively. It is found that the magnetic properties of Mn–Zn power ferrites can be improved with a suitable amount of nano-TiO₂ or normal size TiO₂ addition. At 100 °C, compared to the reference sample without nano-TiO₂ addition, the sample with 0.05 wt% nano-TiO₂ addition shows a more uniform grain structure and a decrease of 9.63% in power loss (P_L) to 394 kW/m³. In this case, the initial permeability of sample declines by 0.3%, compared to that of the sample with 0.03 wt% nano-TiO₂ addition. Besides that, at 100 °C, when the normal size TiO₂ concentration increases gradually to 0.07 wt%, the P_L of sintered samples decreases monotonously to 315 kW/m³. In the temperature range of 90–120 °C, the P_L of the sample with 0.07 wt% normal size TiO₂ addition are lower than 330 kW/m³. It is indicated that the optimal content of normal size TiO₂ is higher than 0.07 wt%. The thermal stability of sintered sample can be considerably improved with a suitable amount of nano-TiO₂ or normal size TiO₂ addition. - Highlights: • The magnetic properties of Mn–Zn ferrites doped with nano-TiO₂ were investigated. • With the content of nano-TiO₂ increasing, the magnetic properties increase. • The power loss (P_L) of the sample doped with 0.07 wt% normal-size TiO₂ is 315 kW/m³. • And the P_L of the sample is lower than 330 kW/m³ at the range of 90–120 °C

[en] Highlights: • Hydrogen produced by pulsed spark discharge in ethanol solution was first studied. • A reactor for on-board hydrogen production was designed. • The influence of many factors on hydrogen production was studied. • Energy consumption was reduced to 1.69 kW h/m"3, better than many others. - Abstract: Hydrogen production from ethanol solution by pulsed high voltage spark discharge was investigated in this work. It is the first time that pulsed high voltage spark discharge in ethanol solution has been used for hydrogen production in the existing documents. A needle–plate reactor for on-board hydrogen production was also designed, which is small-scale and portable for automobiles. By optimizing the reaction conditions, the flow rate of hydrogen can reach 422 mL/min at peak voltage = 30 kV, discharge frequency = 30 Hz, electrode distance = 15 mm, initial ethanol concentration = 50%. It was also found that energy consumption of this method is about 1.69 kW h/m"3, which is better than most existing methods.

[en] Highlights: • Metal work function was first used in hydrogen production by plasma reforming. • Metals with low work function as plate electrode can increase the hydrogen yield. • Energy efficiency was enhanced with low work function metal electrode. • The OES was used to analyze the process of hydrogen production. • Electron temperature and density were estimated. - Abstract: Hydrogen production from an ethanol solution by pulsed high voltage spark discharge was optimized by varying the material of plate electrode. It is the first time that metal work function has been used in hydrogen production by plasma reforming. With low work function metal plate electrode, both energy efficiency and hydrogen yield can be increased. The flow rate and the percentage concentration of hydrogen were achieved 1.3 L/min and 75% respectively while discharging with zinc plate electrode for hydrogen production, which is much better than traditional stainless steel electrodes at the same conditions. The analysis of emission spectra was also accomplished in this work. All the intensity of existing spectral lines showed a decline with higher work function metal as plate electrode, and H"· may be the key to the process of hydrogen production. Additionally, electron temperature and density were also estimated. Both of which were increased with lower work function metal plate electrodes. The electron temperature and density can reach 24,000 K, 7.5 × 10"1"8 cm"−"3 respectively.

[en] Free-standing gel polymer electrolytes with poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) matrix plasticized with tetraethylene glycol dimethyl ether (TEGDME) were prepared and investigated. The as-prepared gel polymer electrolytes exhibited large operating window and acceptable ionic conductivity. When applied in lithium oxygen batteries, the gel polymer electrolyte could support a high initial discharge capacity of 2988 mAh g⁻¹ when a carbon black electrode without catalyst was used as cathode. Furthermore, the battery with gel polymer electrolyte can last at least 50 cycles in the fixed capacity cycling, displaying an excellent stability. Detailed study reveals that the gelling process is essential for the cycling stability enhancement. With excellent electrochemical properties, the free-standing gel polymer electrolyte presented in this investigation has great application potentials in long-life lithium oxygen batteries.

[en] The pore structure of uranium-bearing sandstone is one of the critical factors that affect the uranium leaching performance. In this article, uranium-bearing sandstone from the Yili Basin, Xinjiang, China, was taken as the research object. The fractal characteristics of the pore structure of the uranium-bearing sandstone were studied using mercury intrusion experiments and fractal theory, and the fractal dimension of the uranium-bearing sandstone was calculated. In addition, the effect of the fractal characteristics of the pore structure of the uranium-bearing sandstone on the uranium leaching kinetics was studied. Then, the kinetics was analyzed using a shrinking nuclear model, and it was determined that the rate of uranium leaching is mainly controlled by the diffusion reaction, and the dissolution rate constant (K) is linearly related to the pore specific surface fractal dimension (D_S) and the pore volume fractal dimension (D_V). Eventually, fractal kinetic models for predicting the in-situ leaching kinetics were established using the unreacted shrinking core model, and the linear relationship between the fractal dimension of the sample's pore structure and the dissolution rate during the leaching was fitted

[en] Polycrystalline SnSe bulks were synthesized by a simple and rapid High Pressure and High Temperature (HPHT) method in pressure range of 1–5 GPa, and the thermoelectric performances were assessed after high pressure was released. HPHT can not only sharply shorten synthetic time to 25 min, but also tune thermoelectric properties in a broad range. More importantly, the beneficial thermoelectric properties under high pressure are effectively retained to ambient conditions via “quenching” procedure. The intrinsically high electrical resistivity of SnSe is remarkably reduced by HPHT, which is ascribed to pressure-induced band gap narrowing. A minimum electrical resistivity of 0.1 Ω cm at 5 GPa and maximum power factor of 1 × 10"−"4 Wm"−"1K"−"2 at 3 GPa for SnSe_0_._9_8Te_0_._0_2 are achieved at ambient conditions. Besides, the first principle calculations reveal that high pressure can fundamentally shrink interatomic distances and lattice parameters, which thus lead to a decreased band gap. The pressure coefficient of band gap dE_g/dP = −0.074 eV/GPa is obtained. The variations of electronic structure under high pressure are in accordance with the trend in measured thermoelectric properties. - Highlights: • HPHT a simple and rapid synthetic method (from elements to bulk in 25 min). • HPHT can distinctly reduce the intrinsically high electrical resistivity of SnSe. • The high pressure effects are retained to ambient conditions. • The calculations verify the interatomic distance shrinkage and band gap narrowing.

[en] Highlights: • An experiment of heat flux measurements in a film-cooled thrust chamber has been conducted. • Two-dimensional thermal loads on the inner surface of the combustion chamber were obtained. • A heat flux peak in the axial direction in the near-injector region was measured. • Transient characteristics of temperature and heat flux in the short-time tests are analyzed. • The distributions of thermal loads are significantly influenced by the injector-wall-film interactions. Heat transfer management of the combustion chamber walls of rocket engines is key to predicting their life-cycle. This study used a test apparatus to measure heat transfer on the inner wall of a film-cooled combustion chamber. Experiments on a heat-sink GH₂/GO₂ combustion chamber with film cooling at the injector head were carried out to measure the distribution of wall heat flux and temperature under different chamber pressures and propellant mixture ratios. Averaged heat fluxes and transient values were obtained in the tests, which found a high correlation between transient heat flux and chamber pressure. A heat flux peak appeared in the near-injector region, and its distance from the injector head increased with chamber pressure. The thermal loads decreased obviously when the mixture ratio was increased from 5.0 to 7.0. The measurement data were used to interpolate two-dimensional contours of the wall’s thermal loads. The results will be useful for the thermal-structural analysis needed to provide detailed boundary conditions in the hot-gas-side walls of rocket combustion chambers.

[en] Investigating the seepage characteristics of the leaching solution in the ore-bearing layer during the in situ leaching process can be useful for designing the process parameters for the uranium mining well. We prepared leaching solutions of four different viscosities and conducted experiments using a self-developed multifunctional uranium ore seepage test device. The effects of different viscosities of leaching solutions on the seepage characteristics of uranium-bearing sandstones were examined using seepage mechanics, physicochemical seepage theory, and dissolution erosion mechanism. Results indicated that while the seepage characteristics of various viscosities of leaching solutions were the same in rock samples with similar internal pore architectures, there were regular differences between the saturated and the unsaturated stages. In addition, the time required for the specimen to reach saturation varied with the viscosity of the leaching solution. The higher the viscosity of the solution, the slower the seepage flow from the unsaturated stage to the saturated stage. Furthermore, during the saturation stage, the seepage pressure of a leaching solution with a high viscosity was greater than that of a leaching solution with a low viscosity. However, the permeability coefficient of the high viscosity leaching solution was less than that of a low viscosity leaching solution

[en] The in-situ leaching of uranium mining is a very complicated non-linear dynamic system, which involves couplings and positive/negative feedback among many factors and processes. A comprehensive, coupled multi-factors and processes dynamic model and simulation method was established to study the in-situ leaching of uranium mining. The model accounts for most coupling among various processes as following: (1) rock texture mechanics and its evolution, (2)the incremental stress rheology of rock deformation, (3) 3-D viscoelastic/ plastic multi-deformation processes, (4) hydrofracturing, (5) tensorial (anisotropic) fracture and rock permeability, (6) water-rock interactions and mass-transport (both advective and diffusive), (7) dissolution-induced chemical compaction, (8) multi-phase fluid flow. A 3-D simulation program was compiled based on Fortran and C++. An example illustrating the application of this model to simulating acidification, production and terminal stage of in situ leaching of uranium mining is presented for the some mine in Xinjiang, China. This model and program can be used for theoretical study, mine design, production management, the study of contaminant transport and restoration in groundwater of in-situ leaching of uranium mining. (authors)