Advanced Materials Research Vols. 239-242

Abstract: Dominant 794nm wavelength upconversion emission, which originates from the Tm³⁺: ³H₄®³H₆ transition, has been recorded in Tm³⁺/Yb³⁺ codoped aluminum germanate glass under the 974nm wavelength laser excitation. Judd-Ofelt parameters W₂ (6.52´10^-20cm²), W₄ (9.83´10^-21cm²) and W₆ (1.02´10^-20cm²) indicate a higher inversion asymmetric and stronger covalent environment in the glass material. The spontaneous transition probability of ³H₄®³H₆ was derived to be 1121s^-1, which is responsable for obtaining the powerful 794nm emission. K⁺-Na⁺ ion-exchanged multimode channel waveguide amplifiers have been fabricated based on the Tm³⁺/Yb³⁺ codoped aluminum germanate glass substrate. The relative gain coefficient of a 2.20cm channel waveguide was determined to be 1.58dB/cm at a signal wavelength of 810 nm under 457mW 980nm laser diode excitation.

Abstract: PET(polyester) plain woven fabric deposited with nano-structured silver thin film was prepared by RF (radio frequency) magnetron sputtering at room temperature. The effect of different sputtering technical parameters on the morphology and particle diameters of the nano-structured silver thin film was characterized by AFM(atomic force microscope)and the conductivities of silver thin films were also analyzed under different sputtering technical parameters. The results indicated that the nanoparticles size of sliver thin films increased with higher sputtering power, the conductivity of sliver thin films was first decreased and then markedly enhanced; The nanoparticles size of sliver thin films decreased with higher gas pressure, the conductivity was markedly decreased; The nanoparticles size of sliver thin films increased with longer sputtering time, the conductivity was markedly enhanced, The best conductivity was achieved at the sputtering time of 15min.

Abstract: About 80 kg low carbon steel was refined in a multifunction ladle furnace (AC-LF) with alternating current supplying. The argon-hydrogen gas mixtures were injected into the electric arc zone through one hollow graphite electrode. The flow rate of the gas mixtures was 3 m³/h. Results of the tests and the calculation based on the plasma local equilibrium thermodynamics and metallurgical thermodynamics theories show that, when the argon-hydrogen gas mixtures are injected into the electric arc zone, the carburetion rate is 4.7×10^-6 per minute for the steel heated by conventional AC-LF, which is 1.26 and 1.51 times of the heats blown 90%Ar-10%H₂ and 80%Ar-20%H₂, respectively. The carburetion rate is reduced by 20% at least when argon-hydrogen gas mixtures are blown into the furnace. When H₂ content in the gas mixtures reached 20% from 0, the decarburization rate increased but the total reaction rate decreases by 1.59×10^-6 per minute.

Abstract: To satisfy the forming need of single-basin with a flange, sensitivity analysis is used to optimize the shape on the basis of the initial shape which gotten by the backward simulation method of analysis software ETA/Dynaform5.5.The optimum blank shape for unilateral constrained square cup deep-drawing is determined, and the optimized results were analyzed and compared before and after. Some measures about blank optimization will be given to such parts.

Abstract: This paper takes the butt joint of axle case steel as research object, simulates the real-time three dimensional dynamics CO₂ shielded welding of welding stress field by FEM software ANSYS and obtains the axle case steel 390Q’s transient stress field of weld zone at different welding speed. On that basis, the feasible dynamic simulation method of three-dimensional stress welding field which provides theoretical basis and guidelines for optimizing welding technology and norm welding parameters was proposed. The result of welding stress simulation shows that the welding stress is the lowest when the optimum welding speed is 5mm/s.

Abstract: Efficient methods of non-destructively measuring chlorophyll content (Chl) across a wide range of greenness in grape leaves are necessary for a producer to effectively monitor the status of the crop. Wet chemical methods and handheld leaf Chl meters such as the Minolta SPAD-502 Chl meter(Markwell,1995) have traditionally been used for this purpose. Recently, the availability of small and affordable radiometers , which uses Near infra-red and Red edge(CI_{red edge})( Mark R. Steel, 2008b), for Chl estimation in grapevine leaves, has provided means to estimate Chl from reflectance measurements. The two methods were equally accurate measuring pigments at low to moderate Chl levels. But, when Chl exceeded 300 mg/m², SPAD sensitivity to Chl declined noticeably and the accuracy of Chl estimation by the CI_{red edge} was much higher than that of the SPAD meter, the chlorophyll index was found to be capable of accurately estimating pigment contents across a much greater Chl range than the SPAD meter. However, in this paper an artificial-intelligence technique, the Support Vector Machine (SVM^LightV6.01) model was introduced to establish the relationship between the Chlorophylls content and reflectance of 400-750 nm spectrum, variation of species and growth stages, which can much more perfectly compensated the reflectance that was absorpted by anthocyanin and carotenoids and scatterd because of different leaf thickness, density, or surface properties. As a result that we have solved the problems such as saturation and/or asymptote in high/or lower content of chlorophyll, and SVM model was found to be capable of more accurately estimating pigment contents across a greater range than the SPAD and CI_{red edge,} thus it can be used for quantitative assessment of early stages of pant stress.

Abstract: The blast-furnace slag （BFS）has been characterized by chemical and phase composition to evaluate its hydration reactivity. It has high potential activity for its glassy structure, so its use to prepare new filling cementation material is possible. New backfilling cementation material composition has been formulated and optimized by activation of BFS. The optimal formula of new backfilling cementation material SL(Slag activated by lime) and SLG(Slag activated by lime and desulfurization gypsum) was 87% BFS, 13% lime and 78.4% BFS, 11.8% lime, 9.8% desulfurization gypsum respectively. Finally, the feature of application performance was analyzed through comparison between new cementation material and ordinary Portland cement with paste and sand mortar experiment. The result showed that material SL and SLG have superior performance to ordinary Portland cement used to mining cemented filling.

Abstract: The flow behavior of a 7039 aluminum alloy and the corresponding microstructural evolution during hot deformation were studied by Gleeble-1500 thermal simulation tests, EBSD and TEM observations with temperatures ranging from 300 °C to 500 °C under strain rates from 0.01 s^-1 to 10 s^-1. It has been shown that the flow stress increases with the decrease in the deformation temperature and increase in the strain rate. The degree of dynamic recrystallization (DRX) increases with the increase in the deformation temperature and strain rate in 7039 aluminum alloy. The complete dynamic recrystallization occurs at 500 °C with a strain rate of 10 s^-1.

Abstract: Ballast-less slab track is the primary structure form of the modern high-speed railway, and cements phalt mortar is the most important component of flexible adjusting layer of slab track structure. This article introduces simply development and application of ballast-less track，then detailed explain the production and research of cements phalt mortar special asphalt lotion .

Abstract: The visible-light photocatalytic activity of titanate nanotubes (TiNTs) sensitized by 5,10,15,20-tetraphenylporphyrin (TPP), 5,10,15,20-tetraphenylporphyrin manganese (MnTPP), 5,10,15,20-tetraphenylporphyrin nickel (NiTPP) and 5,10,15,20-tetraphenylporphyrin zinc (ZnTPP), respectively, was investigated by the photocatalytic degradation of methyl orange (MO) as a probe reaction. The results showed that the central ions of porphyrins had an important influence on the photocatalytic activity of the samples. The activity was in the order of TiNTs-ZnTPP > TiNTs-TPP > TiNTs-NiTPP > TiNTs-MnTPP. Combined the result of absorption spectra with that of fluorescence spectra, it was demonstrated that various visible-light absorption and photoelectron transfer caused by the central ions of porphyrins were the decisive factor for the visible-light photocatalytic activity of the sensitized TiNTs.