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Zn reduction was investigated by the vacuum carbothermic reduction of hemimorphite with or without CaF 2 as catalyst. Results indicate that CaF 2 can catalyze the carbothermic reduction of zinc silicate, decrease the reaction temperature and time. The lower the reaction temperature and the more the amount of CaF 2 , the better the catalytic effect. The optimal process condition is obtained as follows: the addition of about 10% CaF 2 , the reaction temperature of 1373 K, the molar ratio of C to Zn Total of 2.5, the pressure of system lower than 20 kPa, the reaction time of about 40 min. Under the optimal process condition, the zinc reduction rate is about 93% from hemimorphite.

Li4Ti5O12 powders were prepared by so-gel method using tetrabutyl titanate, lithium acetate and absolute alcohol as starting materials. Li4Ti5O12-polyaniline (Li4Ti5O12-PAn) composite was prepared by in situ polymerization method using aniline, ammonium persulfate and hydrochloricarried as starting materials. Li4Ti5O12-PAn composite was characterized by X-ray diffractometry (XRD), infrared spectrum (IR) combined with electrochemical tests. The results show that the electrical conductivity is enhanced obviously due to the introduction of PAn to Li4Ti5O12. Li4Ti5O12-PAn composite exhibits better high-rate capability and cyclability than Li4Ti5O12. The composite can deliver a specific capacity of 191.3 and 148.9 mA·h/g, only 0.13% and 0.61% of the capacity is lose after being discharged 80 times at 0.1C and 2.0C, respectively.

SnO 2 -Li 4 Ti 5 O 12 was prepared by sol-gel method using tin tetrachloride, lithium acetate, tetrabutylorthotitanate and aqueous ammonia as starting materials. The composite was characterized by thermogravimertric (TG) analysis and differential thermal analysis (DTA), X-ray diffractometry (XRD) and transmission electron microscopy (TEM) combined with electrochemical tests. The results show that SnO 2 -Li 4 Ti 5 O 12 composite derived by sol-gel technique is a nanocomposite with core-shell structure, and the amorphous Li 4 Ti 5 O 12 layer with 20–40 nm in thickness is coated on the surface of SnO 2 particles. Electrochemical tests show that SnO 2 -Li 4 Ti 5 O 12 composite delivers a reversible capacity of 688.7 mA·h/g at 0.1 C and 93.4% of that is retained after 60 cycles at 0.2 C . The amorphous Li 4 Ti 5 O 12 in composite can accommodate the volume change of SnO 2 electrode and prevent the small and active Sn particles from aggregating into larger and inactive Sn clusters during the cycling effectively, and enhance the cycling stability of SnO 2 electrode significantly.

LiMn2O4/Li4Ti5O12 composite was synthesized by in-situ composite technique using LiMn2O4, lithium acetate, tetrabutyl titanate as starting materials and characterized by various electrochemical methods in combination with X-ray diffractometry (XRD), infrared (IR) spectroscopy and scanning electron microscopy (SEM). The results show that Li4Ti5O12 is coated on the surface of crystalline LiMn2O4 to form LiMn2O4/Li4Ti5O12 composite. The structure of LiMn2O4 does not change due to the introduction of Li4Ti5O12. By being coated with Li4Ti5O12, the rate capability and high temperature cyclability of LiMn2O4 is improved greatly. At room temperature, the discharge capacity of LiMn2O4/Li4Ti5O12 composite is more than 108.4 mA·h/g and the capacity loss per cycle is only 0.053% after 20 cycles at 2.0C. While at 55 °C, the discharge capacity of LiMn2O4/Li4Ti5O12 composite is more than 109.9 mA·h/g and the capacity loss per cycle is only 0.036% after 60 cycles at 1.0C.

SnO 2 -CuO nanocomposite powders were prepared by chemical coprecipitation method using SnCl 4 5H 2 O, NH 3 H 2 O and Cu(NO 3 ).3H 2 O as raw materials. The powders were characterized by thermogravimertric(TG) analysis and differential thermal analysis(DTA), X-ray diffraction(XRD), and scanning electron microscope(SEM). The electrochemical properties of SnO 2 -CuO and undoped SnO 2 powders as anode materials of lithium ion batteries were investigated comparatively by galvanostatic charge-discharge experiments and AC impedance. The results show that SnO 2 -CuO nanocomposite powders with the average particle size of 87 nm can be obtained by this method. The structure of SnO 2 does not change with the introduction of CuO, but the average particle size of nano-SnO 2 decreases. SnO 2 -CuO nanocomposite powders show a reversible capacity of 752 mA h/g and better cycleability compared with nano-SnO 2. The capacity retention rates after 60 cycles of nano-SnO 2 -CuO and SnO 2 are 93.6% and 92.0% at the charge-discharge rate of 0.1 C, respectively, which suggests that the introduction of CuO into SnO2 can improve the cycleability of nano-SnO 2.

It is observed that the parameter of seismic inhomogeneous degree (GL value) calculated from the earthquake catalog shows obvious abnormal changes prior to strong earthquakes, indicating the state change of local seismic activity. This paper focuses on the mechanism for the abnormal changes of the GL values based on the sequences of acoustic emission for three types of rock samples containing macro-asperity fracture; compressional en-echelon fracture and model-III shear fracture. The results show that for the three types of rock samples, there are continuous abnormal changes of GL value (>1) just before the non-elastic deformation occurs or during the process of nucleation prior to the instability. Based on the experimental results, it seems that the process of creep sliding and resistance-uniformization along fault zone is the possible mechanism for the abnormal changes of GL value before rock fractures.