Advanced Materials Research Vol. 650

Abstract: We developed the methods for purification of OMF from green glumes of cereals ears by hydrophobic and reverse phase choreographies. The study of properties of OMF shows that it could find widest application for vegetative reproduction of the trees plants in forestry, gardening and viticulture. Also OMF find wide application for conservation of rare and endangered species of plants by stimulation of germination of the weak germinated seeds. It is very important of the application of OMF for the increasing of tolerance of crop plants to tress conditions. In contras of all bioregulators which applied in agriculture and ecology OMF acts at concentration hundreds times less.

Abstract: The TiC/Fe steel matrix composites were prepared by gelcasting technology of selecting the appropriate gel system and additives, the reasonable technological parameters. The toluene and 2-hydroxyethyl methacrylate (HEMA) were as gel system, oleic acid as dispersant. The rheological property, curing process and performance of the body were analyzed. The results show that the monomer (HEMA) content of 4.6wt% and oleic acid to 2wt% which increased the solid content from 50 to 54vol.%. The relative density of green body is 59.6%, the intensity is 28MPa. After sintering, the complicated shape was prepared.

Abstract: Rare earth silicates (RE2_SiO₅ or RE₂Si₂O₇; RE=Er, Lu, Y, Yb etc.) possess a low silica activity and good thermal stability, making them good candidates for EBC top coating materials. We have performed first-principles total energy calculations for the Er₂O₃-SiO₂ pseudo binary system. The crystal lattice parameters and internal atomic coordinates of Er₂SiO₅ and Er₂Si₂O₇ are optimized, and the electronic structure and formation enthalpies are calculated. The present study provides a theoretical basis for exploring practical applications of the materials.

Abstract: The methods of constitutive modeling of restrained recovery for Shape memory alloys (SMAs) were described in this paper and experiments were carried out to provide the essential data for the methods. The present mathematical constitutive models are inconvenient for engineering applications. Then a back propagation (BP) neural network model was developed for restrained recovery of SMAs. This BP neural network model can learn the hysteresis of SMAs in the process of heating and cooling based on its properties of nonlinear function mapping and adaptation, and it can predict the complete restrained recovery stress of SMAs with different initial strains. The predicted results obtained from the proposed BP model agree well with the experimental data. Moreover, the proposed BP model is more simple, convenient and low cost compared with the present mathematical constitutive models.

Abstract: ffects of high magnetic fields (HMF) up to 19.81T on pearlite phase transformation are studied by examination of the microstructures of a Fe-0.47C-2.3Si-3.2Mn (wt %) alloy partially isothermally processed above the eutectoid temperature. The results show that granular pearlite (GP) can be obtained at earlier transformation stages. The evolution of the granular pearlite is always accompanied by the formation of lamellar pearlite. TEM analysis reveals the existence of sub-grain boundaries within GP colonies and indicates that the nucleation of ferrite matrix in GP belongs to multiple nucleation mechanism. Most of carbides at the early stage of pearlite formation are found to precipitate at the α/γ interface--the growing front of ferrite phases, and some of coarse carbides can further develop into thin lamellar cementite.

Abstract: The microstructure and tensile properties of the as-cast and as-extruded Mg-12Li-1Zn-xSn (x=1, 3, 5, 8, wt.%) alloys were investigated. The alloys are mainly composed of β-Li phase, Mg₂Sn phase. With the increase of Sn content, the microstructure of as-cast alloys is refined. After extrusion processing, grain size is obviously refined, and the Mg2Sn phase is broken into tiny particles. The elevated-temperature tensile behavior of the alloy was investigated at 373~523k under the strain rate of 1×10^-2~1.7×10^-4s^-1. The results indicate addition of Sn can improve the strength and plasticity, when the content of Sn is 5.0 wt.%, the as-extruded alloy possesses good superplasticity, which obtains the maximum elongation of 134.4% under a low strain rate of 1.0×10^-3s^-1 at 523K.

Abstract: A new kind of silica microspheres were first synthesized with chloropropyltrimethoxysilane (WD30) and tetraethoxysilane (TEOS) by sol-gel method. And hybrid membrane was prepared by incorporating the as prepared filler into polydimethylsiloxane (PDMS). The IR, swelling density(Dsw) and mechanical properties of these composites membranes were studied by means of IR analysis and tensile testing. The experimental results showed that both mechanical properties of these composites were significantly improved by using the as-synthesized filler. The filler synthesized in this research not only increased the volume and reduce the cost of HPDMS, but also reacted with the PDMS. The vulcanztion density was increasedwith the interaction between the filler and the PDMS chains. This new kind of silica microspheres is an effective reinforcement filler for PDMS composite.

Abstract: The present study investigated the effect of isothermal aging up to 2000 hours on the intermetallics formed between Sn-4Ag-0.5Cu lead free solder on electroless nickel electroless palladium immersion gold surface finish (Ni-Pd-Au). For all parameters, aging have an effect of changing the intermetallic morphology to coarser and dense structure. The intermetallic compound formed for the interconnection of the lead free solder changes with increased aging time from (Cu,Ni)₆Sn₅ compound to (Ni,Cu)₃Sn₄. At the end of the 2000 hours aging time, it changes to Ni₃Sn₄. This is the effect of Cu element availability during the intermetallics growth process. Starting from as reflow process, (Pd, Ni)Sn₄ intermetallics formed near the interface of the solder joint. The formation of the (Pd, Ni)Sn₄ intermetallics act like a diffusion barrier to slow down the growth of interface intermetallics. Lastly, Au element was detected in the Pd-Sn based intermetallic after aging more than 1000 hours.

Abstract: Gold-poly (3,4-ethylenedioxythiophene) (Au-PEDOT) nanowires with Au nanoparticles embedded in the polymer matrix and polyvinylpyrrolidone (PVP) modified Au-PEDOT coaxial nanocables with a core-shell structure have been synthesized by a new and facile self-assembly method. The morphology and structure features of the composites were characterized by transmission electron microscopy, selected-area electron diffraction, and energy-dispersive x-ray spectrometry. The room-temperature electrical conductivity of the casted composite films was about 0.21 S/cm. Photoresponse of the films were also investigated with respect to wide potential applications of the multifunctional composites. Clear photocurrent switching characteristic during switching on/off of a xenon lamp was observed.

Abstract: The ink penetration behavior depends on the coating surface structure and surface properties of the coating layer in the papermaking process, which include coating recipes and coating conditions, etc. The objective of this experiment was to investigate the relationship between binder content and ink absorption using laser scanning confocal microscope (LSCM). Fluorescent ink was used to observe and characterize ink penetration and distribution in coated paper by LSCM. The results indicated that higher binder content could result in higher amount ink absorption. With the increasing of binder content, ink penetration depth in coated paper increased. Sample G2 with 20 parts binder produced the most unevenness ink distribution. It could be concluded that the coated paper with 25 parts binder compared with the other samples resulted in higher ink usage and better printing quality.