Advanced Materials Research Vols. 756-759

Abstract: Chlorophyll fluorescence images of lettuce in four nitrogen levels were studied to investigate the influence of nitrogen on fluorescence parameters. The results indicated that, at seedling period, Fo and Fm declined with the increase of the amount of nitrogen fertilizer. Fv/Fm had a downward trend after the first rise with the increase of the amount of nitrogen fertilizer. And the influence of nitrogen on Yield, qp, qN were not obvious. At tillering stage, Fo, Fm were on a same level in every nitrogen level. Yield, qp and ETR decreased with the increase in the amount of nitrogen. At mature stage, in addition to in the severe lack of nitrogen level, Fo and Fm reached the maximum of the whole growth period. In the normal nitrogen amount, Fv/Fm, Yield, ETR, qp were high, but qN was very low.

Abstract: In this paper, PP cotton loosing mechanism by cotton loosing machine are in-depth studied, and then influence factors of cotton loosing machines performance to long fiber PP cotton are analyzed to improve performance of the machine.

Abstract: Derived the approximate relationship between minimum cutting thickness and tip radius, ratio of vertical load and shear force, friction coefficient between tip and sample. Wire was being processed by changing the load size. The critical load of chip formation and machining thickness were found from atomic force scan picture. Contrast tests were done by transforming the specimen. The experimental results are basically consistent with the derived values.

Abstract: Four flavonoid glycosides were isolated from the pulps of Elaeagnus angustifolia and identified as Quercetin 3,4'-O-β-D-diglucoside (1), Isorhamnetin-3-O-β-D-galactopy-ranoside (2), Quercetin 3-O-β-D-Galactopyranoside-4'-O-β-D-glucopyranoside (3) and Isorhamnetin 3-O-β-D-Galacto-pyranoside-4'-O-β-D-glucopyranoside (4). Among which, the compounds 1, 3 and 4 were isolated for the first time from this plant. The antioxidant activities of the four compounds were evaluated by measuring their reducing power and ability to scavenge the ABTS radical, DPPH radical and to inhibit superoxide anions. The results indicated that theses compounds exhibited antioxidant activities with a dose-dependent manner in all tested models, and had some structureactivity relationships. The order of potential antioxidant capacity was as follows:1>3>2>4. Considering related reports, the flavonoid might be responsible for antioxidant activity of pulps of E. angustifolia.

Abstract: Ni-Mn-Zn ferrite films were deposited on Si substrate with CeO2/YSZ(YSZ:yttria-stabilized ZrO2) buffer layer by pulsed laser deposition (PLD). The effect of CeO2/YSZ buffer layer on the Ni-Mn-Zn ferrite film was studied by XRD, SEM and VSM. The results revealed that the CeO2/YSZ buffer layer can improve the films crystallinity, smooth the roughness of film, reduce the film crack and lead to a homogeneous microstructure. The saturation magnetization (Ms) higher than 240 emu/cm3 can be obtained. It also found annealing process can improve the film crystallinity and the magnetic properties, decrease the coercivity (Hc).

Abstract: Based on the experimental result of the flexure capability of reinforced concrete beams strengthened by carbon fiber sheets, the stress distribution changes only after steel yielding and carbon fiber sheets function better. However serious the extent of the damage is before strengthened, the tensile strain of main steel reaches about 1.6 times of the yield strain for the secondary grade of steel as failure happens. To satisfy the object reliability indicator, reliability is analyzed using the ratio of the steel strain at the balanced failure to the yield strain as variable to obtain its optimum value, which is coincide with the experimental result, and makes better consistency between calculated reliability indicator and object reliability indicator.

Abstract: The microstructure characteristics of complex binders under two curing conditions were studied by observing the micro-morphology, analyzing the pore character and means of spectrum test. The results showed that high temperature curing improved the pore structure formed in the early hydration period and reduced the porosity and the coarse pores in pastes. More hydration products were generated on the surface of fly ash particles that made the microstructure of pastes more denser than cured in room temperature. However, high temperature curing had insignificant influence on the CaO/SiO₂ ratio of C-S-H gel in pastes and contributed little to the improvement of the later hydration degree and microstrcture of fly ash-cement pastes.

Abstract: Recently, the finite element (FE) numerical simulation technology has become an effective approach to solve problems in precise manufacturing of sheet metal parts in aircraft industries. Based on FE analysis software Pam-Stamp, Chengdu Aircraft Industrial Company developed a FE system for analysis of typical sheet metal forming. This system has been successfully applied in the development of new products, which shortens the preparation cycle of process and enhances the capability for rapidly researching and developing.

Abstract: China's iron and steel industry was rapided development, however, the steel bridge construction is very slow. Timely development of steel - concrete composite bridge will be the major trend of the future bridge construction.This paper intruduces the theory, advantages, applications and development trends of steel-concrete structure, by comparion of steel-concrete structure with prestressen concrete structure. Finaly, illustrates the need for steel-concrete structure used in bridge construction.