Advanced Materials Research Vol. 676

Abstract: Effect of four materials including glycine, arginine, proline and sodium glutamate on survival of Bifidobacterium bifidum during freeze-drying was studied by measuring the viable counts of before and after freeze-drying. The addition of glycine, arginine, proline and sodium glutamate (%, w/v) were all 1.0%, 2.0%, 3.0%，4.0% and 5.0%. Results were as follows: addition of glycine, arginine, proline and sodium glutamate into B. bifidum paste could significantly improve the survival rate of B. bifidum and the number of viable cells of lyophilized powder. The optimal concentrations of glycine, arginine, proline and sodium glutamate were 4.0%, 4.0%, 3.0% and 2.0%, the survival of B. bifidum was 87.49%, 84.28%, 67.50% and 69.01%, respectively.

Abstract: Gas hydrates are group ice-like crystalline compounds, which form through a combination of water and suitably sized guest molecules under low temperature and high pressure conditions. The important properties of hydrate are very high gas to solid ratio, 1m3 of hydrate may contain up to 175m3 of gas (at standard condition). When the conditions change, the methane hydrate can dissociate to methane and water. Hydrate meta-stable (self-preservation) property has been reported by some researchers in recent years. If we can utilize the property economically in addition to its high-density gas containing property, it is possible to store and transport stranded natural gas at higher temperature and lower pressure compared to the conventional liquid natural gas method. The authors conducted laboratory experiments of methane hydrate dissociation in order to examine its potential for application to natural gas storage and transportation. As the result, relatively extremely slow dissociation was confirmed within temperature range between -7.5°C and -3°C. These results seem to be very promising for practical application of self preservation property to natural gas storage and transportation.

Abstract: Ribbon silicon material is specially designed for solar cell wafers. In this paper, a novel ribbon silicon material “dipping method” has been designed in order to lower the cost of solar cell. The principle and procedure of dipping method were described. In addition, the diffusion of impurities in the silicon wafer and its influence on the efficiency of solar cells were investigated. The photovoltaic performance of polycrystalline silicon solar cells which were based on the metallurgical grade silicon substrate with the thickness of 600μm, was simulated by AMPS1-D software. And some import parameters were obtained including I-V characteristic, 17.004% conversion efficiency. This artic is provided theoretical support to the industrial production of solar cells by dipping method, and it will open a new road to production low cost solar cell.

Abstract: Response surface methodology(RSM) was used to optimize the formulation of one toothpaste with aglycone extracted from Panax notoginseng(APN). Biochemical materials are important components in toothpastes. The addition amount of APN, thickener, different ratios of humectant and friction agent were selected as three factors for the design. Our results showed that the experimental data could be adequately fitted into a second-order polynomial model. Addition amount of thickener and humectant : friction agent had a significant effect on the composite score. The optimum formulation for preparing APN toothpaste was predicted to be: APN, 0.12%; thickener, 1.58%; humectant : friction agent, 1.01.

Abstract: Environment material was a kind of material that considering the environment and ecology protection. Microbe as the key material of sewage treatment system played an important role in environmental protection. The paper researched that a strain of denitrifying phosphorus-removing bacteria could be isolated and screened from dephosphorization system by the conventional microbial breeding technology. The strain was preliminarily appraised itself belong to Pseudomonas sp., ultimately named as PX3.

Abstract: Mining, smelting, processing, and industrial production emissions of waste heavy metal pollution is serious, and the enrichment of heavy metals, it is difficult to be degraded in the natural environment. Conventional methods for removing metals may be ineffective extremely expensive. not eco-friendly.Based on wastes recycling and circular economy, this thesis studied the characteristics of industrial fermentation waste A.niger as adsorbent for sequestering Pb(II) from aqueous solution. .Optimum biosorption was observed to be 72％ at pH 5.5,biosorbent dose 1.5 mg／L, initial Pb(II)concentration 250 mg／L.A.niger can be used as a new economic and eco-friendly environmental materials of metal adsorption.

Abstract: Due to its single-stage high head, compact structure, convenient maintenance, low cost and high reliability, the high-speed centrifugal pump has been widely used in refining, petrochemical, chemical industry, and aerospace engineering fields. However, as the speed increases, the increasingly high demand for stability is showing and cavitation characteristics of the high-speed centrifugal pump is emerging. Reducing the mechanical vibration, hydraulic losses and improving the pressure distribution of the high-speed pump have become one of the main research fields for high-speed pumps. Three types of splitter blades were designed in this paper. Numerical simulations of the 3D steady flow in the high-speed pump have been carried out by using the software ANSYS CFX 12.0 and the comparative analysis of the velocity, pressure distributions and fluid mechanics in the high-speed pump under three different flow conditions were also carried out，Respectively. The effects of splitter blades on the high-speed pump performance were studied by analyzing both its inner flow field and hydraulic performance. The calculated H-Q curve of the high-speed pump was compared with the test results, and they agreed well with each other. The relative error of head at design conditions was lower than that at the non-design conditions.

Abstract: The differential equations of bending-torsional coupled vibration have been established with a switching crack for a Jeffcott rotor system with a transverse crack as the research object. Variable perturbation method has been used to study the stability of bending-torsional coupled vibration of a rotor system with a crack. The theoretical result shows that, when it is close to the natural frequency of 2 times, 3/2 times and 1 times, unstable vibrations exist and conditions of stable vibration. According to the above order, unstable region becomes narrow. While in 1/4 times, 1/6 times, the system is stable. The conclusions provide valuable theoretical basis for a crack rotor system in the real working conditions when corresponding measures need taking.

Abstract: In this investigation, a method combined with thermal-elastic-plastic finite element method and thermo-mechanical coupling method is proposed based on equivalence principle, which is used to predict residual deformation of large thick spherical structure after welding. In this solving framework, according the relationship of strain-stress of welding material, equivalent temperature load of single weld is obtained firstly, and then extended to other welds. Thus, the prediction of welding deformation for large thick spherical structure is obtained. Based on numerical analysis, the optimization of welding position is carried out. Then the optimum welding scheme of large thick spherical structure is presented. The numerical simulation in this paper provides theoretical basis for the process of large thick spherical structure. Moreover, it also provides a reliable method to predict the strain of large thick spherical structure.

Abstract: In this paper, the single disk rotor system with a transverse open crack has been taken as an example; the vibration properties on the system have been discussed theoretically. First, the equations of the motion of this kind of system are established. Then, the conditions, positions and areas of the stable vibrations and the unstable vibrations on the system are studied by applying the Floquet Theory. Finally the influence of several parameters on stability has been discussed.