Aiming at the influence of different material properties on the vibration characteristics of cracked gas turbine compressor blades, the vibration characteristics of cracked compressor blades with three different materials were studied by numerical calculation. The first order bending vibration of a cracked cantilever beam was simplified to a single degree of freedom system. The breathing crack stiffness model was introduced to change the elastic modulus and other parameters of the material. The fourth-order Runge-Kutta method and fast Fourier transform were used to obtain the cantilever beam vibration characteristic diagram, and the relationship between the material properties and the structural vibration was analyzed. The results show that the elastic modulus of the material is proportional to the stiffness, and the stiffness of the material affects the vibration displacement response of the cantilever beam, and the larger the stiffness is, the smaller the vibration displacement is.

LiFePO4/C cathode material was synthesized by mechanical activation combined with carbothermal reduction method.The influences of parameters of mechanical activation(ball-to-power weight ratio,milling media,the atmosphere,temperature of ball-milling) on the structure and performance of the material were investigated.The structure,morphology and electrochemical properties of LiFePO4/C were analyzed by XRD,SEM,optical particle size analyzer,BET method and galvanostatic charge-discharge method,respectively.The results indicate that the optimum processing conditions of mechanical activation are ball-to-power weight ratio =6∶1,ball-milling at 25 ℃ for 6 h with Ar protect atmosphere in agate jar.LiFePO4/C composite material synthesized under this processing condition has fine particle size at 500-600 nm and excellent electrochemical performance with 136 mAh/g at 1 C discharge current.

Aluminum had been used as a current collector for Li-ion battery,but the corrosion of the aluminum might take place in the electrolyte of Li-ion battery,and cause irreversible capacity and safety problem.The characteristic of the aluminum,the mechanism and the effect factors of aluminum corrosion were analyzed.The methods for inhibiting aluminum corrosion were further introduced.

Research progress in recent years on the preparation, modification, how to control crystal size, relationship between structure and performance, and prospect of olivine-type lithium iron phosphate LiFePO4 cathode materials for the lithium-ion batteries was reviewed. Particle size and its distribution, ionic and electronic conductivity, and the content of Fe( ) have much effect on the performance of the samples. The use of inert gas, the addition of conductive dope, and the control of crystal size to gain nano-powder are the useful way to improve the electrochemical performance of LiFePO4.

LiFe0.9V0.1(PO4)(0.95)F-0.15/C was prepared via solid-state carbothermal reaction (CTR). F and V codoping did not alter the olivine structure of LiFePO4 but reduced the particle size and improved the Li+ diffusion coefficient. The cells based on this material showed higher discharge capacity, working voltage, rate capability, and better cyclic performance than that of undoped and F-doped materials.

Ni-Al layered double hydroxides were prepared with spray technique on the base of chemical co-precipitation.The structure of the product was analyzed and the physical properties were tested.Moreover,it was used as cathode active material to manufacture Zn-Ni cell,and then the charge-discharge performance was studied.The experimental results show that the sample has single a phase crystal structure and irregular particle morphology.Its specific surface area reaches 14.1 m2/g and the average particle size is 18.38 mm.The cell has obviously better cycle stability,higher discharge capacity and voltage plateau than that with spherical b-Ni(OH)2 cathode.The average discharge capacity reaches 287.4 mAh/g within 120 cycles at 1 C rate,and the median discharge voltage attains 1.688 V.

LiFePO4/C composite with carbon content of 5wt.% was synthesized by solid state reaction. Core-shell structure was confirmed by scanning electron microscope (SEM) and transmission electron microscopy (TEM). Rechargeable Lithium ion battery based on this compound has reached a high rate capacity of 121.5mAhg−1 under 5C. The rate capability retention between 0.1C and 5C is 86.9%, which is the highest as far as we know. We found the carbon content was 12.7% on the surface of LiFePO4 grain, although the whole carbon content was about 5wt.%. We attribute the improvement of rate capability retention to the existence of the carbon rich surface.

The effect of fluorine doping on the electrochemical performance of LiFePO4/C cathode material is investigated. The stoichiometric proportion of LiFe(PO4)1−x F3x /C (x = 0.01, 0.05, 0.1, 0.2) materials was synthesized by a solid-state carbothermal reduction route at 650 °C using NH4F as dopant. X-ray diffraction, scanning electron microscope, energy-dispersive X-ray, and X-ray photoelectron spectroscopy analyses demonstrate that fluorine can be incorporated into LiFePO4/C without altering the olivine structure, but slightly changing the lattice parameters and having little effect on the particle sizes. However, heavy fluorine doping can bring in impurities. Fluorine doping in LiFePO4/C results in good reversible capacity and rate capability. LiFe(PO4)0.95 F0.15/C exhibits highest initial capacity and best rate performance. Its discharge capacities at 0.1 and 5 C rates are 156.1 and 119.1 mAh g−1, respectively. LiFe(PO4)0.95 F0.15/C also presents an obviously better cycle life than the other samples. We attribute the improvement of the electrochemical performance to the smaller charge transfer resistance (R ct) and influence of fluorine on the PO 4 3− polyanion in LiFePO4/C.

In order to improve the ion conductivity of lithium iron phosphate, the LiFePO4/Li1.3Al0.3Ti1.7 (PO4)3/C composite were synthesized by high temperature solid state method. The influences of firing time, firing temperature and doping contents of Li1.3Al0.3Ti1.7(PO4)3 on the structure and performance of the material were investigated. The structure and properties of the composites were characterized by X-ray diffraction, scanning electron microscopy and galvano-static charge-discharge method, respectively. The results showed that the material doped by 2wt.% of Li1.3Al0.3Ti1.7(PO4)3 which was sintered for 25h at 650°C exhibited the best electrochemical performances and finest particle size distribution about 50nm. When discharge at 0.1C, its discharge specific capacity was 157.7mAh/g.

Chemical co-precipitation was used to prepare Ni-Al layered double Hydroxides doped with both Co and La and each one of them, respectively. The morphologies, specific surface areas, crystal structures and electrochemical performances of the products were analyzed or tested. Experimental results showed that the sample doped with both Co and La had particle shape approximating to sphere. Its specific surface area reached 132.5 m(2)/g and crystallinity was higher than that of the sample doped with La. Because more H2O molecule, CO32- and NO3- anions were intercalated in the interlayer region, the stability of crystal structure was enhanced. On the other hand, the sample had higher redox reaction reversibility and electrochemical activity, and its average discharge specific capacity attained 311.5 mAh/g at 1C rate when used as cathode active material for MH/Ni battery. The electrode with it exhibited excellent cycle stability and better charge-discharge performance than that with Co doped or La doped sample.

SnO2 is an interesting material for a wide array of applications. In this report, pure SnO2 films were deposited on Cu substrates by one-step cathodic electrodeposition without any pretreatment of the electrolyte or post-treatment of the deposit. It was found that the concentration of HNO3 in the electrolyte, ageing of the electrolyte, the electrodeposition temperature, and the electrodeposition voltage are critical to obtain SnO2 films and avoid co-deposition of Sn. By carefully controlling those processing parameters, pure SnO2 films composed of fine particles with good adherence to the Cu substrate have been successfully prepared.

In this paper,using bisphenol A epoxy resin as the matrix,TEPA as the curing agent,silver-plating copper powder as the conductive filler and AA-75 as the dispersant,the silver-plating copper filled epoxy conductive adhesive was prepared.DC low-resistance tester is used to measure the volume resistivity,infra-red spectrometry is used to characterize the adhesives with different amount of curing agent and differential scanning calorimetry is used to determine the optimal curing reaction temperature.The result showed that under the optimal proportions and process conditions the volume resistivity of conductive adhesive is 8.9×10-4 Ω·cm.

In this paper, in order to study the influence of the ratio of disordered/graphitized carbon on the electrochemical properties of LiFePO4/C, three carbon sources were used to synthesize LiFePO4/C samples through a solid-state reaction route. And the results of microstructure, carbon structure and electrochemical properties showed that carbon introduced kept the LiFePO4 olivine structure and most of the residual carbon was disordered. According to the value of disordered/graphitized ratio in pyrolyzed carbon, three carbon sources were arranged as following from low to high: soluble starch<glucose<carbon black. When carbon content was constant(ca. 11%wt.), the LiFePO4/C composite using starch as carbon source gave a lowest ratio of disordered/graphitized carbon, which delivered an initial specific capacity of 139.83 mAh/g at 0.1C discharge rate, and 115.68mAh/g at 5C discharge rate. The rate capability still kept 82.73% of that at 0.1C discharge rate.

In order to study the properties and structure of Sulfonated-poly(ether ether-ketone)/Silica/(SPEEK/SiO2) composite proton exchange membranes (PEM) prepared by ball milling for direct methanol fuel cell (DMFC) application,SPEEK/SiO2 Inorganic-Organic composite membranes were prepared with sulfonation degree 75% SPEEK matrix and SiO2 inorganic phase by ball milling. The properties of composite membranes such as conductivity methanol permeability swelling properties. mechanical properties. SEM and IR were also characterized. The results suggested that SPEEK/SiO2 composite membranes showed a very low methanol permeability,changed between 1.15x10(-8) similar to 1.38x10(-7)cm(2)/s ,which was as much as 1-2 orders lower than commercial Nafion 117 membranes. Composite membranes also exhibited good performance of anti-swelling,its water absorption was only 16.5% and swelling ratio declined to 4.1% at 30 degrees C. The tensile strength of composite membranes with 15wt% SiO2 reached 45.3MPa showed the good mechanical properties of composite membranes. Although the proton conductivity decreased after the addition of SiO2, the proton conductivity was still up to 9.6x10(-3)S/cm with 5wt% SiO2 at 80 degrees C.SEM and IR showed that fine SiO2 particles cross-linked and distributed homogeneously in SPEEK,and there was no agglomerate in composite membrane in SEM image.

LiFePO4 belongs to a new generation cathode material for lithium ion batteries. The improvement of the material's tap density is considered as an important research direction. LiFePO4/C composite was synthesized by a solid-state carbothermal reduction (CTR) method. The iron resource was obtained by the addition of (i) Fe2O3 and citrate ferric or (ii) single Fe2O3 as the Fe3+ precursors during synthesis. The LiFePO4/C composite synthesized with two kinds of Fe3+ precursors exhibited trimodal distribution and consisted of nanometer-sized and micrometer-sized particles, whereas the LiFePO4/C composite prepared with single Fe3+ precursor demonstrated unimodal distribution and was composed mainly of micrometer-sized particles. Because of the nanometer-sized particles filling in the space between the micrometer-sized particles, the composite synthesized with two kinds of Fe3+ precursors exhibited less vacancy than that prepared with single Fe3+ precursor and led to high tap density. The composite synthesized with two kinds of Fe3+ precursors had smaller grain size and resulted in superior discharge capacities at the rates of 0.1–1.0 C to that prepared with single Fe3+ precursor. The two kinds Fe3+ precursors method provides a simple and effective route to rapidly prepare high tap-density LiFePO4 product with excellent electrochemical performance, so it will achieve a wide-range of applications to the production of LiFePO4.

Pure olivine LiFePO4/C composite compounds are synthesized by carbothermal reduction (CTR) method using trigonal anhydrous FePO4 raw material. The physical and electrochemical properties of the prepared samples are investigated in comparison with those of a sample obtained from incompletely crystallized hydrous FePO4·2H2O. The olivine LiFePO4/C prepared with trigonal anhydrous FePO4 has a high discharge capacity of 142mAhg−1 at 0.1C. The composite also displays a better rate capability, a higher discharge capacity and a more stable cycle-life than that synthesized with incompletely crystallized hydrous FePO4·2H2O. The improved electrochemical performance of trigonal anhydrous FePO4 synthesis samples originates mainly from the single-phase structure and small particle size.

Sulfonated poly(ether ether-ketone)(SPEEK)/silica(SiO2)/silicotungstic acid(SiWA) composite membrane was synthesized via spreading method.The morphology,proton conducting performance,methanol permeability and swelling property of the composite membrane were studied.The composite membrane with m(SPEEK)∶m(SiO2)∶m(SiWA)=70∶10∶20 had fine performance,the conductivity at 90 ℃ was 0.018 s/cm,the methanol permeability was 3.4×10-8 cm2/s and 5×10-7 cm2/s at 30 ℃,90 ℃,respectively,the water absorption only increased 17.9% when the temperature raised from 30 ℃ to 80 ℃,the swelling ratio only increased 0.9%.SiO2 and SiWA particles distributed homogeneously in the composite membrane,the particles were fine and there was no agglomerate.

The composite electrode materials of MnO2/acetylene black(AB) were prepared via sonochemistry method and chemical mixing method,respectively.XRD analysis showed that the powder prepared by sonochemistry method presented a structure of α-MnO2,the powder prepared by chemical mixing method was an amorphous of MnO2.The results of SEM and electrochemical experiment indicated that the ultrasonic radiation could make MnO2 homogeneous dispersion with conductive agent,could improve electrochemical kinetics reversibility of the electrode material.The electrochemical specific capacitance of the composite electrode increased two times when AB content was 15%.