[en] By analyzing the behavior and existence form of uranium in different geochemical environments, existence form of uranium and uranium minerals species, this paper expounds the formation mechanism of main commercial uranium mineral--pitchblende: (1) uranium is a valence-changeable element. It is reactivated and migrates in oxidized environment, and is reduced and precipitated in reducing environment; (2) [UO₂(CO₃)₃]^4-, [UO₂(CO₃)₂]^2- coming from oxidized environment react with reductants such as organic matter, sulfide and low-valence iron at the redox front to form simple uranium oxide--pitchblende; (3)the adsorption of uranium by organic matter and clay minerals accelerates the reduction and the concentration of uranium. Therefore, it is considered, that the reduction of SO₄^2- by organic matter to form H₂S, and the reduction of UO₂²⁺ by H₂S are the main reasons for the formation of pitchblende. This reaction is extensively and universally available in neutral and weakly alkaline carbonate solution. The existense of reductants such as H₂S is the basic factor leading to the decrease of Eh in environments and the oversaturation of UO₂²⁺ at the redox front in groundwater, thus accelerating the adsorption and the precipitation of uranium

[en] The E coil highly expressing rhIL-6 constructed by our department was fermented and rhIL-6 products were extracted and purified. The specific activity of the purified rhIL-6 products reached 4.83 x 10⁸ IU/mg. The rhIL-6 products were used to treat BALB/c mice injured by ⁶⁰Co irradiation for six days (2 μg/big/each). The results showed that the bleeding time, coagulation time and prothrombin time of the rhIL-6 treatment group were significantly shorter than those of the control group (P<0.01), the platelet count and WBC increased by 130% and 165% in the treatment group as compared with the control, the numbers of CFU-Mix cultured in vitro and CFU-s in spleen were significantly higher than those in the control group (P<0.01). These results suggest that rhIL-6 exerts beneficial effects on the recovery of mice from radiation-induced injuries of hematopoietic stem/progenitor cells, and thus helps recovery from radiation injury of bone marrow and hematopoietic function. (17 refs., 4 figs., 5 tabs.)

[en] The topological properties of silicene and Sn film decorated with chemical functional groups (–H, –F, –Cl, –Br, –I) are investigated by the first-principle calculations. It is found that Sn films decorated with F, Cl, Br and I are topological insulators with sizable gap while the other combinations are normal insulators. The phase transition of X decorated silicene and Sn film was investigated by applying external strain. Our results pointed out that the normal insulators can transform into topological insulators with sizable gap under critical strain. The research provided new routes to design 2D topological insulator with sizable gap which has wide applications in next-generation spintronics devices. - Highlights: • The inverted band order can be obtained with applying external strain. • Band gaps of TIs can be enhanced by external strain. • Quantum phase transition is observed under a critical strain for X−Si and X−Sn

[en] It is found that the radius for a stable strangelet is a decreasing function of temperature in quark mass density- dependent model. To overcome this difficulty, the authors extend this model to quark mass density- and temperature- dependent model in which the vacuum energy density at zero baryon density limit B depends on temperature. A constant B = B₀[1-a(T/T_c) + b(T/T_c)²] is introduced and the regions for the best choice of the parameters are studied

[en] LiNi_0_._8Co_0_._1_5Al_0_._0_5O_2 (NCA) microspheres covered by a nanoscale Li_2TiO_3-based shell were synthesized by a facile strategy based on a solvothermal pre-coating treatment combined with a post-sintering lithiation process. The morphology, structure and composition of the Li_2TiO_3-coated NCA samples were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning scanning electron microscope (SEM) with an energy-dispersive X-ray spectroscope (EDS), and transmission electron microscopy (TEM). Owing to the complete, uniform and nanoscale Li_2TiO_3 coating shell, the resultant surface-modified NCA microspheres used as Li-ion battery cathode materials manifest remarkably enhanced cycling performances, attaining 94% and 84% capacity retention after 200 and 400 cycles at 0.5 C, respectively, which is much better than the pristine NCA counterpart (60% retention, 200 cycles). More impressively, the surface-modified NCA also shows an intriguing storage stability. After being stored at 30 °C for 50 days, the coated NCA-based cells are subjected to be cycled both at room and elevated temperatures, in which the aged cells can still remain 84% capacity retention after 200 cycles at 25 °C and 77% capacity retention after 200 cycles at 55 °C, respectively. All these results demonstrate that the Li_2TiO_3-coated LiNi_0_._8Co_0_._1_5Al_0_._0_5O_2 microsphere is a promising cathode material for Li-ion batteries with long lifespan. - Graphical abstract: Nanoscale Li_2TiO_3-based shell encapsulated LiNi_0_._8Co_0_._1_5Al_0_._0_5O_2 (NCA) microspheres are fabricated through a solvothermal pre-coating treatment combined with post-lithiation process. The surface-coated NCA as cathode materials shows a remarkably enhanced cycling performance and storage stability for long lifespan Li-ion batteries. - Highlights: • Li_2TiO_3 is used as coating materials for layer structured LiNi_0_._8Co_0_._1_5Al_0_._0_5O_2 cathode. • Solvothermal coating strategy is employed to strengthen surface coating. • Coating layer improves the velocity of Li"+ migration on electrode surface. • Erosion from the HF and CO_2 on electrode is greatly suppressed.

[en] Due to the absence of weak-links in grain boundaries, less anisotropy, and high availabilities at reasonable cost, magnesium boride, MgB${}_2$, has been studied extensively in the past decade. It has relatively high critical temperature, which is correlated to crystallographic and electronic structures. Two topological indices, the electric connectivity index and valence energy level connectivity, are characteristics of compound branching. We develop the Gaussian process regression (GPR) model to shed light on the relationship between topological descriptors and superconducting transition temperature for doped MgB${}_2$ superconductors. The model is highly accurate and stable, which contributes to fast predictions of superconducting transition temperature.

[en] Recently, Fe-based superconductors have shown promising properties of high critical temperature and high upper critical fields, which are prerequisites for applications in high-field magnets. Critical temperature, T${}_c$, is an important characteristic correlated with crystallographic and electronic structures. By doping with foreign ions in the crystal structure, T${}_c$ can be modified, which however requires significant manpower and resources for materials synthesis and characterizations. In this study, we develop the Gaussian process regression model to predict T${}_c$ of doped Fe-based superconductors based on structural and topological parameters, including the lattice constants, volume, and bonding parameter topological index H${}_{31}$. The model is stable and accurate, contributing to fast T${}_c$ estimations.

[en] Lithium titanate enriched by "6Li isotope is considered as a candidate of tritium breeding materials for fusion reactors due to its excellent performance. The reuse of burned Li_2TiO_3 pebbles is an important issue because of the high costs of "6Li-enriched materials and waste considerations. For this purpose, reprocessing of Li_2TiO_3 pebbles by graphite bed method was developed. Simulative Li_2TiO_3 pebbles with low-lithium content according to the expected lithium burn-up were fabricated. After that, Li_2TiO_3 pebbles were re-fabricated with lithium carbonate as lithium additives, in order to gain the composition of lithium titanate with a Li/Ti ratio of 2. The process was optimized to obtain reprocessed Li_2TiO_3 pebbles that were suitable for reuse as ceramic breeder. Density, porosity, grain size and crushing load of the reprocessed pebbles were characterized. This process did not deteriorate the properties of the reprocessed pebbles and was almost no waste generation

[en] The characteristics are investigated of a transient grating induced by laser in glasses doped with CdSSe semiconductor and the nonlinear response time of the material is obtained. Also the properties of photoluminescence of the glasses are studied and a blue shift in luminescence spectra with increasing intensity of the input beam is observed. It is assumed that the nonlinearity of the material is due to band filling in semiconductor microcrystallites. (author)

[en] Fixed bed reactors are widely used in desulfurization processes. However, this kind of reactors has an obvious disadvantage leading to discontinuous operation that the catalysts and adsorbents must be regenerated periodically. As a continuous operated reactor, moving bed reactor can let both gas and solids move through the reactor, making it possible to remove the saturated adsorbents as well as deactivated catalysts. Meanwhile, fresh gas and solids can be fed into the reactor. This paper builds mathematical model of adsorptive moving bed reactor based on Claus Process. The model is simulated with Aspen Custom Modeler. Simulation results show that adsorptive moving bed reactor has good performance in Claus Process. Under the reaction conditions, the adsorption ability is limited by the temperature. Adequate increment of adsorbent volume fraction in the solids can improve the reactor’s performance. (paper)