Applied Mechanics and Materials Vols. 84-85

Abstract: The physical model for the optical pulse propagating in the amplifier has been established. Within the normal dispersion region of the fiber, the evolution of the optical pulse in the amplifier has been simulated numerically, and the influence of gain dispersion on the propagation characteristics of the pulse has been discussed emphatically. The results show that, during the propagation of the ultrashort optical pulse in a distributed fiber amplifier, group velocity dispersion and Kerr nonlinear effect will affect the pulse profile and spectrum. For the ultrashort optical pulse with a wideband spectrum, the influence of gain spectrum on the propagation characteristics of the optical pulse, in essence, is that of gain dispersion, which is equivalent to a loss mechanism and will generate gain narrowing effect, so it should be considered in the design of an amplifier system.

Abstract: Composite insulated wall panels using carbon fiber grid in combination with expanded polystyrene (EPS) insulation have been produced for over 5 years. The carbon fiber grid and the EPS act together to provide shear transfer between the wythes of the composite panel. A design procedure has been developed, based on testing at Washington University and North Carolina State University. The approach discussed here is to ensure that the flexural strength, the cracking moment, and the deflection are all within acceptable limits. This paper first discusses the testing that has been performed to develop the material properties used in the design procedure. Then methods for computing the flexural strength, the cracking moment and the deflection are also presented. Deflections are not often an issue and cracking moments can be easily controlled by the amount of prestress. Therefore, the most important concern is providing adequate shear transfer. The design procedures discussed here were later verified by full scale testing at North Carolina State University.

Abstract: The aromatic polyester from diphenolic acid and isophthaloyl chloride was synthesized by interfacial polycondensation with tetrabutylammonium chloride as phase transfer catalyst. The structure was characterized by means of FTIR. The poly(DPA-IPC) solution was titrated by aqueous HCl solution. The titration curves were obtained. The trend of reduced viscosity of solution with concentration was studied. Besides, the stability of poly(DPA-IPC) in aqueous basic solution was discussed.

Abstract: An attempt has been made to increase the corrosion resistance properties of medium steel substrate by using silica sol.The results show that: sol-gel method can increase corrosion resistance of phosphating coating. PS(silicon sol coated after phosphating )’s corrosion potential reduced more than P(phosphating sample)’s and its corrosion density also reduced.Polarizationg resistance of PS can improved many times.R2 of PS more reduced than P,but R3 improved more than ten times and R4 improved over sixty times by using equivalent circuit to fit EIS measurement. Corrosion resistance of PS was higher than that of P.

Abstract: Since MSWI fly ash enriches heavy metals and many toxic components and these components would potentially leach when the ashes are land filled, it is regulated as hazardous waste in many countries. Electrokinetic removal, an electrochemically assisted extraction method, has recently been adopted as a new method for removal of heavy metals from MSWI fly ashes. But the generation of metal hydroxide precipitation near the cathode decreased conductivity of electrokinetic removal system and limited metal extraction from the sample area. In this study, cation exchange membrane was used in electrokinetic removal experiment to improve this method. After 192 hours of electrokinetic removal, about 15%Cd,20%Pb, 30% Zn, and 10% As was removed from 2.850kg MSWI fly ash. It showed positive effect compared to the trial test. But there still exists some problems, such as low removal efficiency. Further work should be done to solve it.Moreover, the high conductivity in fly ash limits the current , which in turn causes low electroosmotic flow. While electroosmotic flow is the main factor leting the heavy meatals release from fly ash, it would become the focus in further experiment to look for ways increasing the electroosmotic flow in sample cell.

Abstract: Ln³⁺ (Ce³⁺ and Tb³⁺) -doped Lu₂SiO₅ thin films were fabricated by Pechini sol–gel method combined with spin-coating technique on silicon substrates. The results of XRD patterns indicate that the films are completely crystallized at 1100 °C, the AFM observation reveals that the phosphor films are uniform and crack-free, consisting of closely packed grains with an average size of 200-300 nm. The PL and PLE spectra show the characteristic emission for Tb³⁺ and Ce³⁺, the optimum concentrations are found for LSO:Tb³⁺ (8%) and LSO:Ce3+ (2%) with respectively, the effect of heat-treatment temperature on the luminescent properties is also investigated.

Abstract: The bioleaching effect of different concentrations of silver ion catalysis on chalcopyrite tailings has been investigated in shaking flasks. In this paper, A.t ferrooxidans were selected for conducting the bioleaching process. Experiments were carried out under the condition of pulp density 150 g/L, inoculation amount 106~7 cells/mL, pH around 2.0, culture temperature 30°C, rotation speed 150 r/min. The silver ion concentrations varied from 0 to 0.05g/L. After a bioleaching time of 24 days, 82% and 55% of copper was dissolved from the ore for the silver ion concentration of 0.01 g/L and 0.001 g/L respectively, compared with only 37% and 13% recovery for the silver ion concentration of 0 and 0.05 g/L. Preliminary tests showed that the silver ion concentration had a markedly catalytic effect on the copper extraction. The experimental results also showed that high silver ion concentration would inhibit the copper extraction. That was because the silver ions at high concentrations are toxic and they can suppress the bacteria growth and oxidation activity.

Abstract: This paper mainly studied the Viscosity of polyethylene glycol dilaurate and the surface tension, discussing the effects of temperature, concentration, rotate speed on the viscosity. The results show that the viscosity of the long carbon chain fatty acid was higher than the short carbochain, and the viscosity decreasing trend with increase of the temperature. The internal structure of emulsion may take place changing due to the temperature changing. The liquid crystal disintegration or occurred phase change could result that the viscosity appeared the abrupt peak. The viscosity of emulsion maybe appear one or two peaks with the changing of concentration, that the viscosity decreasing with increase of the temperature and rotate speed.

Abstract: The first-principle method based on the pseudopotential plane-wave is adopted to analyze O₂ adsorption on the LaMnO₃ (001) surface. The calculated results indicate that, LaMnO₃ presents half-metal properties by calculating the band structure and density of states (DOS). In the MnO₆ octahedron, the O-Mn-O bond is mainly covalent, on the contrast, O-La-O bond is mainly ionic. Molecular oxygen can adsorb on the LaMnO₃ (001), M2 may be the most favourable adsorption mode. The adsorption mode leads to the formation of .The valence of Mn in the adsorption sites after adsorption of M1 and M2 is Mn^3+0.25, Mn^3+0.31, respectively. M2 may be the most adsorption mode that can make Pd ⁰ to shift Pd²⁺ more quickly in the process of direct synthesis of diphenyl carbonate (DPC) using the catalyst -Pd supported on the LaMnO_3.

Abstract: This paper discusses the effect factors and proposals between milling process of Ⅱ-powdery emulsion explosives and raw materials, production process parameters. The effect from percentage of the additive M on dispensability and detonation parameter of explosive can be analyzed through the experiments.