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Dispersive soils are highly sensitive to moisture content, and its particles are prone to hydraulic erosion and scouring. The objective of this study is to determine the impact of antecedent moisture content on the erosion of dispersive soils in the Zhenlai area and establish erosion characteristics. The soil samples were collected from the Zhenlai area in the western part of Jilin Province, China. The erodibility was assessed at five different antecedent moisture content levels (with a 2% increment) by simulating rainfall in a laboratory setting on small-scale slopes. The results indicate that there are significant differences in erosion characteristics among slopes with different antecedent moisture content levels. The sediment yield from slopes with antecedent moisture content above the optimum moisture content is 60% lower compared to slopes with moisture content below the optimum moisture content. The optimum moisture content was served as a clear erosion threshold. When introducing the soil parameter of matric suction, it was found that it effectively characterizes the sensitivity of dispersive soils in this area to variations in antecedent moisture content and their impact on slope erosion. [ABSTRACT FROM AUTHOR]

Bletilla striata is a good source of plant polyphenols which have regulatory functions on melanogenesis. In the present work, to maximise the yields of total polyphenols extracted from B. striata, the effects of Tween-60 concentration, shear speed, shear time, ethanol concentration, temperature, and material-to-solvent ratio on extraction of polyphenols were assayed using the high-shear dispersing emulsification technology (HSDE). The obtained data were analysed using the response surface methodology, which showed that the optimal extraction conditions were as follows: Tween-60 concentration of 2.00%, ethanol concentration of 69%, shear speed of 17,200 rpm, and extraction temperature of 55°C. Under these conditions, the extraction of the total polyphenols from B. striata was 13.79 ± 0.34 mg/g. Furthermore, the anti-melanogenesis activity of the total polyphenols extracted from B. striata was evaluated using α-MSH-induced B16F10 cells. Results showed that the total polyphenols from B. striata could significantly inhibit melanin production. Overall, these results presented the optimal conditions for the extraction of total polyphenols from B. striata, and also revealed the potential anti-melanogenesis values of B. striata polyphenols. [ABSTRACT FROM AUTHOR]

Making use of defects modification to P(VDF-TrFE) via either high energy electron irradiation treatment or copolymerizing VDF-TrFE with a small amount of chlorinated monomer to form a random terpolymer, we demonstrate that high electromechanical responses can be realized in P(VDF-TrFE) based polymers. It will be shown that in the stretched and irradiated 68/32 mol% copolymer, a transverse strain of 4.5% and a transverse electromechanical coupling factor [k.sub.31] of 0.65 can be induced under a field of 85 MV/m. In addition, the irradiated copolymer also exhibits a high elastic energy density, ~ 1 J/c[m.sup.3]. For PVDF based terpolymers such as P(VDF-TrFE-CFE) terpolymer (CFE: chiorofluoroethylene), an electrostrictive strain of more than 7% can be obtained. To elucidate the microstructure changes due to the defects modification in P(VDF-TrFE) based polymers, synchrotron X-ray measurement was carried out on the irradiated copolymers and the results show that, the irradiation converts the polar-phase into a non-polar phase. In addition, X-ray date show that the polar-phase can be induced, at the expense of the non-polar phase, by external fields, confirming that the field induced conformation change is responsible for the observed high electromechanical responses. Although the modified PVDF based polymer exhibits the highest room temperature dielectric constant (60 versus below 10), it is still far below those in the inorganic materials. Experimental results show that by using delocalized electrons in conjugated bonds an all-organic composite with a dielectric constant more than 400 can be achieved. As a result, a strain of near 2% with an elastic energy density higher than 0.1 J/c[m.sup.3] can be induced under a low applied field of 13 V/[micro]m. The strain is proportional to the applied field and the composite has an elastic modulus near 1 GPa. Index Terms--Electroactive polymers, relaxor-ferroelectric polymers, high dielectric constant polymers, electrostriction, field effect actuators.

Author(s): Q. M. Zhang (corresponding author); Hengfeng Li; Martin Poh; Feng Xia; Z.-Y. Cheng; Haisheng Xu; Cheng Huang Electroactive polymers (EAPs) can behave as actuators, changing their shape in response [...]

Research is presented concerning the characterization of the pi peizo-optical coefficients of Pb(Zn1/3Nb2/3)O3 - PbTiO3 ferroelectric single crystals as an investigation of their photoelastic effects.