Advanced Materials Research Vol. 669

Abstract: Well-crystallized 0.7(Na1/2Bi1/2)TiO3-0.3(K1/2Bi1/2)TiO3 (NKBT) thin films were prepared on quartz substrates using a sol-gel process. The sign and magnitude of both the real and imaginary parts of third-order nonlinear susceptibility (3) of the thin films have been determined by the Z-scan technique performed at 532nm with picosecond laser. The nonlinear refractive index n2 and the nonlinear absorption coefficient of the thin films are determined to be 3.13×10-8 esu and 3.84×10-9 m/W, respectively. The real part and imaginary part of the third-order nonlinear susceptibility (3) of the sample were calculated and the values were 1.49×10-16 m2/V2and 3.96×10-18 m2/V2, respectively. The results suggested that the nonlinearity is dominated by the refractive for the films and the NKBT thin films is a promising material for applications in nonlinear optical devices.

Abstract: To synthesize morphology- controlled nano- copper with excellent lubrication properties as lubricant’s additive, chemical reduction synthesis method was used coalescing in situ via liquid paraffin as resolvent and modification with polyethylene glycol (PEG-2000). The as- prepared Cu nanopieces with 35.59 nm average length and 21.03 nm average width were characterized by X-ray diffraction (XRD), and transmission electron microscopy (TEM). The tribological behavior of Mobil 1 5W-30 lubricating oil with nano- Cu were measured by ball- on- disk UMT- Ⅱ tribometer and analyzed by SEM and EDS. It is found that the tribological performance of Mobil 1 5W- 30 with nano- Cu is improved, and the optimization addition is 0.4% (Cu wt) with the lowest friction coefficient.

Abstract: The influences of re-sintering on the structure and electrochemical performance of LiNi1/3Co1/3Mn1/3O2 were researched in this paper. The synthesized materials were characterized and tested by means of X-ray diffraction (XRD) and electrochemical measurements respectively. It was found that the re-sintered samples with better well-ordered layered structure, more perfect crystallization and more complete crystal structure will be formed with increasing temperature. Moreover, reasonable re-sintering time was required. The materials re-sintered at 860°C for 2h exhibited the best electrochemical performance, including high initial discharge capacity of 150.6 mAh•g-1 and coulomb efficiency of 84% at 0.2C rate.

Abstract: We fabricated mono-dispersed hollow waxberry shaped ß-quartz GeO₂ by a facile one-step synthesis in emulsion at room temperature. TEM images indicated that hollow waxberry shaped GeO₂ were consisted of nano-sphere whose average size were estimated to be 20 nm. The growth mechanism and optical properties of the products were also investigated. The possible formation mechanism of the hollow interior is proposed as the Ostwald ripening. The optical properties of the ß-GeO₂ nanoparticles with hollow shapes were also studied with photoluminescence spectrum, which reveals a broad emission, suggesting potential applications in electronic and optoelectronic nanodevices. These attractive results provide us a new simple method further used to fabricate other specific hollow structure and indicate hollow waxberry shaped GeO₂ may have potential applications in light-emitting nanodevices.

Abstract: General Purpose Polystyrene (GPPS) and High Impact Polystyrene (HIPS) were foamed with supercritical carbon dioxide in the batch foaming process. Foaming behaviors of GPPS and HIPS were investigated. The cell diameters and cell densities of GPPS and HIPS vary strangely with foaming conditions and can be explained by the classical nucleation. The competition between cell growth and cell nucleation is used to explain these strange foaming behaviors. The glass transition temperature (Tg) almost remains constant with the foaming temperature rising.

Abstract: Sol-gel method was applied to synthesize nano-TiO2 particles doped with metal and non-metallic elements. Nano-TiO2 particles were doped at different calcinations’ temperatures with S and Fe, Ce and La, respectively. A comparison was performed on the effect of different metallic elements on nano-TiO2 particles doped with the same non-metallic element S. X-ray diffraction results indicated that the diameter of doped nano-TiO2 particle was smaller than that of non-doped nano-TiO2 particles. The minimum diameter of nano-TiO2 doped with Ce and S was about 8nm, while that of nano-TiO2 doped with La and S was about 9nm. The minimum diameter of nano-TiO2 particles doped with Fe and S was about 10nm. In addition, with the increase of calcinations’ temperature, the size of nano-TiO2 particle increased. All nano-TiO2 particles doped with double elements were antae. Methyl orange was used to simulate the pollutant to analyze the photocatalytic property of doped nano-TiO2. The results indicated that the doped element had some effect on the photocatalytic property of nano-TiO2, and varied for different doped metallic elements. Among them, the degradation rate of methyl orange by nano-TiO2 doped with La and S under the calcinations’ temperature of 550 °C reached 28.97%.

Abstract: This paper will conduct a systematic study on method of recovering Ge from pulverized fuel ash in Lincang prefecture, Yunnan province. Details are like this, in view of the fact that Ge contained in pulverized fuel ash is wrapped up by a lot of Silica, Cao, magnesium oxide and is difficult to react with hydrochloric acid, so, first, have the pulverized fuel ash grinded to 200 meshes; then, ammonium fluoride should be put into 85-90°Cdilute sulphuric acid solution to produce hydrogen fluoride so as to destroy silicon dioxide and calcium oxide contained in the pulverized fuel ash. Meanwhile, dilute sulphuric acid solution dissolves magnesium oxide, by doing so, Ge will be released to react with sulfuric acid and produce Sulfuric acid Ge, and Ge will go into the solution；as for low state Ge（e.g,GeO,GeS）contained in the pulverized fuel ash which is difficult to be dissolved by sulfuric acid, sodium chlorate will be used as a kind of oxidant to change bivalence Ge into tetravalence Ge, then dissolve it into the solution, after the liquid-solid separation, sulfuric acid leaching solution rich in Ge will be obtained. Then, tannic acid will be used as precipitant to recover Ge from the leaching solution, and Ge concentrate will be produced through distillation and roasting. After this, put Ge concentrate on hydrochloric acid distillation to get germanium tetrachloride, After going through strenuous evaporation, distillation and hydrolysis, germanium dioxide with high purity will be yield. This paper has conducted conditional tests and discussion on the process parameters which will influence recovery Ge from pulverized fuel ash, including the dosage of Sulfuric acid, ammonium fluoride, sodium chlorate ,tannic acid and extraction time to find out the prior controlling condition of Ge recovery，under this prior condition, Ge leaching rate is as high as 84%，and tannic sinking Ge rate is as high as 98%. The pulverized fuel ash, after recovering Ge, can be used to backfill the mine pit, besides, most of the lixivium after recovering Ge can be recycled, and the rest of it will be released after neutralized up to the standard by lime. This process enjoys the following quality: high Ge recovery rate, less time used during the process ,less consumption of auxiliary material, easier to control the process, avoiding the potential pollution on the environment and lower cost involved in it, therefore, which is a kind of efficient and economic process of recovering Ge from pulverized fuel ash.