Advanced Materials Research Vols. 391-392

Abstract: LiNi_0.5Mn_1.5O₄ material was synthesized by PVP-assisted gel-combustion method and examined as a cathode material for lithium-ion batteries, working together with a room temperature ionic liquid electrolyte and a lithium metal anode. The LiTFSI-Pp₁₃TFSI ionic liquid electrolyte was obtained by dissolution of solid lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) in liquid N-methyl-N-propylpiperidinium bis(trifluoromethanesulfonyl) amide (Pp₁₃TFSI). The LiNi_0.5- Mn_1.5O₄/LiTFSI-Pp₁₃TFSI/Li cell was tested by galvanostatic charging/discharging and compared with standard carbonate/LiPF₆ electrolyte. At low current (0.05 C) density, the LiNi_0.5Mn_1.5O₄/ LiTFSI-Pp₁₃TFSI/Li cell exhibited stable cycling for 11 cycles, but it degraded rapidly in subsequent cycles. Preliminary tests showed that both the cathode and anode interfacial reaction contributed to the rapid degradation.

Abstract: The soil productive forces are mainly affected by soil erosion as soil nutrients and organic carbon are taken away. On the premise of analysis of the last 17 years’ data of rainfalls and vegetation coverage in Xiejiawan small watershed, the grey model was established to forecast and evaluate the losses of organic carbon caused by water erosion in the hilly area of purple soils. Moreover, according to comparison of four-dimensional, five-dimensional and six-dimensional model groups, we found that, six-dimensional GM (1,1) model was the best one, posterior-variance-test accuracy of which amounted to the first class, and maximum simulated relative error ,average simulated relative error and predicted relative error of which were respectively 43.26 % ,16.85% and -17.09%, besides, its simulation and prediction accuracy was also high. Furthermore, the accuracy of simulated forecast value was all satisfactory. So the SOC loss by water erosion in purple areas of Xiejiawan small watershed was simulated and predicted well by grey model, also the unique evolution patterns of changing organic carbon in purple soil by water erosion could be well described and explained by the grey model.

Abstract: Series of anatase TiO₂ nanoparticles with different particle sizes were prepared by a fast microwave-assisted method and conventional hydrothermal method, using ionic liquids, 1-ethyl-2,3-dimethylimidazole bromide and N-butylpyridinium hexafluorophosphate, and polyethylene glycol as templates, respectively. The crystal structures and morphologies of the nanoparticles were characterized by XRD and SEM. Their light harvesting capabilities and band gap energies were investigated by UV-Vis diffuse reflectance absorption spectra. The surface –OH groups were detected by FT-IR and the photocatalytic activities were estimated by photodegradations of rhodamine B aqueous solutions under simulated sunlight irradiation. The results show that the type of the template and synthetic method affect the particle sizes of the products, and the photocatalytic activities of the TiO₂ nanoparticles are close related with their particle sizes.

Abstract: The effect of Sr addition on microstructure evolution of Mg-6Zn-2Al-2Ca-xSr (x=0.5, 1, 2, 3）alloys were investigated by using scanning electron microscope (SEM), X-ray diffraction (XRD) and optical microscope. The result show that Sr constitutional under cooling can significantly refined microstructure of alloys and formed rod-shaped Al4Sr phase in Mg-6Zn-2Al-2Ca alloys, while alloy microstructure turned to be coarse with further increase in Sr content. The addition of Sr slows down the precipitation power of Mg-6Zn-2Al-2Ca alloys and inhabits the β phase continuous precipitation.

Abstract: The adsorption and diffusion of polydimethylsiloxane (PDMS) with different chain lengths on a silicon (111) surface were studied by molecular dynamics simulations. The relative dielectric constant was selected to be 1 to mimic a vacuum. The chains were all present as two dimensional (2D) adsorption conformation on the surface but different conformations and dynamic properties were found in the two absolutely different environments. The relationship between the adsorption energy of the different chain lengths and the degree of polymerization follows a linear function and the average adsorption energy per segment is -0.42 kcal/mol. In addition, the diffusion coefficient (D) of these chains scales with the degree of polymerization (N) as N_-3/2.

Abstract: Papain and alcalase were successively used to hydrolyze grass carp scales for preparation of crude polysaccharide. Chondroitin sulfate were further purified by DEAE-Sepharose Fast Flow and Sepharose 6 Fast Flow gel column chromatograph, and indentified by IR, NMR, element analysis and chemical analysis. Three polysaccharide fractions including chondroitin sulfate were fistly obtained from grass carp scales. The weight-average molecular weight of chondroitin sulfate was 46168 Da. The contents of various elements (C, H, N, S, O) in chondroitin sulfate were 28.89 %, 3.80 %, 3.36 %, 6.71 % and 47.16 %, respectively. The results of IR, NMR and chemical analysis exhibited that the sulfate group in chondroitin sulfate be O-linked in position 4 of N-acetyl-D-galactosamine.

Abstract: Corn stover is a largely feasible and cheap renewable resource with low commercial value. An attractive alternative is utilization of corn stover for chemical industry，medicine，biochemistry etc. However, the production costs are still too high to apply on commercialization. The purpose of this study was to use the response surface methodology (RSM) to optimize of cellulose salvation by ZnCl₂ after the steam explosion .The solution of cellulose that had been pretreated with 87% ZnCl₂ at 139 °C for 49 min resulted in an optimum solubility of 76.2%.

Abstract: Six ternary silane systems were selected for the separation factor (s) calculation. These systems were: methyldichlorosilane+methyltrichlorosilane+benzene, methyldichlorosilane+ methyltrichlorosilane+dimethyldichlorosilane, methyldichlorosilane+methyltrichlorosilane+ toluene, methyltrichlorosilane+methylvinyldichlorosilane+toluene,methyldichlorosilane+methyltrichloro- silane+methylvinyldichlorosilane, dimethyldiethoxysilane+methyltriethoxysilane+ethanol. Based on the Antoine constants, critical parameters of the pure components and Wilson model parameters, the separation factors were obtained through a program. The effect of temperature and mole fraction to s was also discussed.

Abstract: Six binary silane systems were chosen to calculate the activity coefficients (γ) and free energies of mixing (ΔG_m). These systems included: methyldichlorosilane + methyltrichlorosilane, methyldichlorosilane + methylvinyldichlorosilane, methyldichlorosilane + toluene, methyltrichlorosilane + methylvinyldichlorosilane, methyltrichlorosilane + toluene, methylvinyldichlorosilane + toluene. Based on the Antoine constants, critical parameters of the pure components and Wilson model parameters, γ and ΔG_m were calculated. The influence factors of these thermodynamic properties were also discussed.

Abstract: High gain, rare-earth ions co-doped multicomponent phosphate glasses with different doped concentration ratio were prepared and investigated by means of absorption and fluorescence spectroscopy in order to investigate the influence of different doped concentration ratio on material optical properties. The main results showed that there was a strongest absorption at 980nm and saturated at 1530nm when Er³⁺and Yb³⁺ concentration ratio was 4:1, which is the optimum ratio. It is also demonstrated that reaction and energy transfer mechanism between different ions in rare-earth co-doped system, which is significant for their interest in the fields of optical fiber amplifier and laser.