Advanced Materials Research Vol. 663

Abstract: A Membrane aerated bioreactor (MABR) capable of simultaneous nitrification and denitrification in a single reactor vessel was developed to investigate the factors of the simultaneous removal of nitrogen and carbon. The results showed that when the bubble point pressure of membrane modules is 25kPa, the relationship between oxygenation efficiency and intransmembrane pressure were not positively correlated, controlling the transmembrane pressure was 15kPa, oxygen supply rate (OSR) was the highest. During the earlier stage of operation, reducing the hydraulic retention time of MABR could improve the integral removal efficiency, when the HRT was 2h, the removal of COD and ammonia - nitrogen were respectively 70.29% and 52.3%. The dissolved oxygen in the reactor had a significant influence, with the dissolved oxygen （DO） concentration about 0.5mg/L, ammonia-nitrogen and total nitrogen removal efficiency was better, the removal rate were 79.5% and 63% respectively. The reaction tank had CO2 accumulation, and caused pH reduced to 5.8, the operation should maintain the pH at 7.5 by increasing the alkalinity of the raw water.

Abstract: AlN dielectric thin films were deposited on N type Si(100) substrate by reactive radio frequency magnetron sputtering that directly bombardment AlN target under different sputtering-power and total pressure. The crystal structure,composition,surface and refractive index of the thin films were studied by XRD, SEM, AFM and elliptical polarization instrument. The results show that the surface and refractive of the thin films strongly depends on the sputtering-power and total pressure,the good uniformity and smoothness is found at 230 W, Ar flow ratio 5.0 LAr/sccm, substrate temperature 100°Cand 1.2 Pa. The crystal structure of the as-deposited thin-films is amorphous，then it transforms from blende structure to wurtzite structure as the rapid thermal annealing(RTA) temperature changes from 600 to 1200°C. The refractive index also increases with the RTA temperature it is increasing significantly from 800 to 1000°C．

Abstract: Hydrogen peroxide is a green oxidizer. On-site electrochemical production of hydrogen peroxide has potential to become a new way for raw water pre-oxidation. The performance of electro-generation hydrogen peroxide was studied in the electrochemical reactor equipped with graphite felt as cathode and RuO2-IrO2-coated titanium mesh as anode. The effect of water flow rate, air flow rate and current density on concentration of hydrogen peroxide and energy consumption was studied. Results indicate that the optimal condition for the lowest energy consumption is to directly produce 5 mg/L of hydrogen peroxide as compared with producing high concentration followed by dilution. It was found that electrochemical pre-oxidation technology had a good effect on sterilization and removing turbidity and stink for raw water.

Abstract: A new nanostructure, 1D In₂O₃ nanorod, have been grown on single silicon substrates by Au catalyst assisted thermal evaporation of In₂O₃ and active carbon powders. The morphology and structure of the prepared nanorods are determined on the basis of field-emission scanning electron microscopy (FESEM) and x-ray diffraction (XRD). The field-emission properities of In₂O₃ nanorods have been measured and analysed. The growth mechanism of the In₂O₃ nanorods can be explained on the basis of the vapor–liquid–solid (VLS) processes.

Abstract: Metallic oxide ZnO short-nanorod of 33-83 nm in diameters and length up to 0.3um.with biological compatibility are environmentally fabricated by organic solvent-assisted annealing pro- cess. The sample was characterized by X-ray diffraction, field-emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HRTEM). It demonstrates that the obtained ZnO short-nanorods have good crystal quality. A growth mechanism is proposed. This paper establish base for application of Metallic oxide short-nanorod to the area of bioscience in our future work.

Abstract: A numerical model is given to identify equivalent parameters of composite materials, using BP neural network algorithm. Taking Filament-wound composite pressure vessels as the research object, finite element models are first constructed .Getting node displacements as network training samples, the mechanical parameters as output information of network for effective training, the equivalent material parameters can be obtained. The satisfactory numerical validation is given and results show that the proposed method can identify the equivalent modulus and the equivalent Poisson’s ratio of the Filament-wound composite pressure vessels with precision. The computational efficiency is improved with BP neural network.

Abstract: In this paper, we used the electron beam (e-beam) evaporation to deposit Ge thin film on glass, and used microwave annealing (MWA) system of 5.8 GHz frequency for thin film crystallization. Then, we compared the MWA experiment results of sample sheet resistance (Rs), crystallization strength and cross section with those using traditional rapid thermal annealing (RTA) equipment. We found that MWA can get poly-Ge thin film with (111), (220) and (311) crystallization directions and optimal Rs at a temperature of about 450 ° C without affecting the film thickness. By comparison, RTA equipment can only reduce the sample Rs at least temperature of 550oC.

Abstract: Lead strontium zirconate titanate (PSZT) ceramic is as one kind of piezoelectric materials can convert between stress and electric. Because of high performance, low cost of PSZT material, this kind of material are widely researched [2, 3] and used in the areas such as electrical sensors, actuators, alarm equipments etc [1]. As the more widely applications of the PSZT material, improving its piezoelectric properties becomes more important [4]. In this paper, for improving the electrical properties of PSZT material, elements manganese (Mn) or cerium (Ce) is doped into the bulk PSZT material. It has been found that, when the doping amount of MnO₂ is 0.15wt%, the electrical properties are improved to: tgδ=0.0095, kp=0.634, d₃₃=611pC/N and ε=2523. When the doping amount of CeO₂ is 0.2wt%, the electrical properties are enhanced to: tgδ=0.0168, kp=0.621, d₃₃=585pC/N, ε=3324.

Abstract: The mechanical responses of granular materials are affected significantly by the properties of the individual particle. In order to establish the link between the micro and macro parameters, series of numerical biaxial simulations are carried out using two-dimensional discrete element method. The microscale mechanisms of mechanical behavior of granular materials are investigated through sensitivity analyses. The key influence of microscale parameters on the strength and deformation are discussed respectively. The peak strength depends on void ratio, friction coefficient and confining stress significantly. The elastic modulus is affected by friction coefficient, confining pressure and stiffness ratio, especially when the friction coefficient ranges from 0.1 to 0.3. The samples with different initial void ratio under the same loading condition can finally achieve the same critical state; the critical states at micro and macro scale are both independent of the initial void ratio.

Abstract: MnO2 nanoparticle was produced using liquid coprecipitation method, CNT was produced using microwaveplasma chemical vapor deposition(MWPCVD). SEM and EDS were used to examine the morphology and the elements of the samples. The diameter of MnO2 particle is about 300nm. And the CNT sample has a diameter about 10~20nm and a length longer than 5 µm. Two methods, namely annealing and doping CNT, were used to modify the electrochemical characteristics of MnO2 particle. The electrochemical characteristics were tested using galvanostatic charge-discharge cycling. And the results demonstrated that the prepared MnO2 have a good pseudocapacitance behavior and power characteristic. And the specific capacitor (SC) of MnO2 particle was about 145.41F/g, the SC of CNT was 136.30F/g, the one up to 179.89F/g with a dopant of CNT.