[en] An ultrafast pump-probe spectroscopy was used to investigate the transient phenomena of the excitons induced by the electric field to gain an insight into the effect of electric field on the organic light emission diode. At high excitation density of 230 μJ/cm² the decay of the singlet excitons showed fast and slow components. The amplitude factor and the relaxation time of the fast component are field-dependent. The slow component is field-independent, and its relaxation time-constant is about 890 ps. We also observed the longitudinal acoustic phonons with sound velocity of 17 A/ps generated by excitation pulse.

[en] Non-oriented Fe-7.1wt.% Si as-cast strips were produced by twin-roll strip casting process. Then the as-cast strips were hot rolled with different reductions, followed by warm rolling and final annealing. The microstructure, texture evolution and magnetic properties were investigated in detail. The texture of hot rolled sheets with 40% reduction showed strongest {001}<110> texture, whereas the dominated texture was turned into {110}<001> and {110}<112>as the reduction was increased to 56% and 68%. After warm rolling and annealing, the average grain size was decreased firstly and then increased with an increase in hot rolling reduction. In the case of 40% hot rolling reduction, the recrystallization texture was dominated by strong γ (<111>//ND) texture. With an increase in hot rolling reduction, the γ texture was gradually weakened while α (<110>//RD) texture was enhanced. In addition, relatively stronger {100} texture was presented in the sheet of 68% hot rolling reduction. The highest B₅₀ value attained was 1.66 T and the lowest P_10/400 was 24.26 W/kg at a reduction of 56%. (paper)

[en] As the utmost downstream dam in the main stream of Xijiang River, Changzhou Hydro-Junction has changed the original hydrological characteristics and ecological environment of Xijiang River. In order to grasp the fish distribution and standing crops after reservoir impoundment, a split beam echo-sounder EY60 (120 kHz) was used in the river channel from Guiping to Wuzhou in April 2014, 2015, and 2016. The average fish density in the survey area was 0.1215±0.4198 ind.m^-3 in 2014, 0.0190±0.1232 ind.m^-3 in 2015 and 0.0107±0.0186 ind.m^-3 in 2016. According to the horizontal distribution data, fish density showed significant difference in different area and the density in the upper area was significantly higher than that in other areas. Moreover, fish density was negatively correlation with water depth. As a whole, the Target Strength (TS) decreased in the past three year, TS was significantly different among the three areas and showed a decreasing tendency from the dam area to the upper area. Fish resources decreased gradually, as indicated by the decreased fish density and miniaturized fish sizes in the past three years. (paper)

[en] This paper presents a solar-powered lighting system, using cold-cathode fluorescent-lamps (CCFLs), with its battery-charging circuit and lamp-ignition circuit being separated so that its solar panels can be installed at any distance deemed necessary away from the lighting site in order to receive the maximum solar energy available. This system adopts the maximum-power point tracking (MPPT) method to control the power output of the solar panels and uses the zero-voltage switching (ZVS) DC-DC converter, as the charging circuit, to increase the panels' power generation efficiency and the charging circuit's conversion efficiency. The electronic ballast circuit for the CCFL is constructed with a half-bridge inverter, a resonant inductor, and a Rosen-type piezoelectric transformer, which forms a piezoelectric resonant-type inverter: to simplify the circuitry and to improve the power conversion efficiency, the ballast circuit is designed to directly step up the battery voltage in igniting the lamp. We also establish the transmission-parameter model for the piezoelectric resonant-type inverter to provide the base for the electric-power circuit design. Our experimental results indicate that the proposed system possesses some advantages, such as greater energy efficiency, circuitry simplicity, and so on, and is suitable for night lighting in house yards, parks and advertising panels