Control of Snow Falling Flow around NACA0015 Blade using a Plasma Electrode with Weather Resistant Design

The plasma actuation (PA) effect on the snow falling flow was investigated using a plasma electrode with weather resistant design and the natural snow wind facility of the Hokkaido University of Science. NACA0015 test blade with chord length c of 300 mm was used. Wind tunnel tests were carried out under the angle of the attack of the blade was fixed at 15 degrees, and the main flow velocity is U=5 m/s. PIV (Particle image velocimetry) measurements were conducted on various PA conditions using natural dry snowflakes as a tracer. When the actuator was driven under the condition of the fundamental frequency of F=50 kHz, and the pulsed modulated frequency f of fc/U=1 and Duty ratio (Ratio of plasma ON time to pulse duration time) =1%, movement of snowflakes was controlled the most effectively tested. It was clarified that the fundamental frequency of PA also affects the control of snow flow. Under snowfall conditions, the weather resistant designed plasma electrode has suffered no damage and operated successfully.     

Changes of Aldehyde Levels in Defatted Soybean Extract

Aldehyde levels in defatted soybean extracts were measured by using aldehyde dehydrogenase. The level increased during incubation of flour-water suspension and its centrifuged extract at pH 6.5, while it decreased markedly at alkaline pHs. This aldehyde-eliminating activity was observed in 1:5 flour:water ratio, but was not in 1:20 flour:water ratio. ¹⁴C-labelled acetaldehyde added to 1:5 flour:water extract was converted into acetic acid. Fractionation of the extract indicated that a heat-labile protein and a heat-stable compound with low molecular weight were required for the aldehyde-eliminating activity.     

一种微小物体精密定位的直线微工作台

提出了一种基于平滑冲击驱动原理的精密定位直线微工作台.通过采用微小强磁铁作为摩擦元件,减小了由摩擦元件磨损而产生的摩擦力的变化,从而提高了微工作台的稳定性.设计制作了微工作台样机,并对精密定位工作台的动态特性和静态特性进行了实验研究.结果表明,微工作台体积小(20mm×10 mm×3 mm),可实现6 nm的精确定位,最高驱动速度可达5.4 mm/s,最大行程可达20 mm.     

Comparative study of behavior of inhaled samarium and cerium in mice

Distribution of Sm and Ce in mice was investigated after inhalation exposure to their oxide particles of 5 μm diameter and 15 mg/m3.Sm and Ce were mainly distributed in lung,their concentrations decreased with passing time,and their concentrations in lung were correlated with exposure periods.Concentrations of Ce were lower than that of Sm in each point.Sm was also distributed in the other organs and bone but Ce was scarcely detected.These results suggest that the behaviors of Sm and Ce inhaled were different,although their chemical properties are similar.     

绕击雷侵入波下1 100 kV电气设备的绝缘配合研究

用电气几何模型(A-W theory)和EMTP程序定量研究了中国特高压变电站设备的绝缘配合问题。与出厂雷电冲击试验电压波形不同,由绕击雷电侵入波在主变压器上产生的电压波形在波头有高频振荡且波尾时间长。考虑多重雷的绕击雷电侵入波,在线路入口安装瓷柱式避雷器和罐式避雷器可以更好地保护断路器和高抗。     

Quality Evaluation of Fish Meat by 31 Phosphorus-Nuclear Magnetic Resonance

³¹Phosphorus-Nuclear Magnetic Resonance (³¹P-NMR) was used to evaluate degree of freshness of loach muscle depending on metabolic changes of high energy phosphate compounds. The phosphocreatine ([PCr])/inorganic phosphate ([Pi]) ratio was found to be a sensitive index of early metabolic hypofunction. Ratios of [PCr]/β-phosphate of ATP ([β-ATP]), and [Pi]/[β-ATP] were demonstrated to be appropriate indexes to estimate such metabolic changes in fresh fish. The intramuscular levels of creatine phosphate, ATP and pH were maintained at higher levels in blood-drained loach than in untreated fish. The freshness of fish which were bled and washed at lower temperatures were better preserved.     

Quantitative analysis of work hardening and dynamic softening behaviors of Cu-6 wt pct Ag binary alloy based on true stress vs strain curves

The work hardening and dynamic softening behaviors of Cu-6 wt pct Ag binary alloy were studied by hot compression tests under temperature range of 700-850℃ at strain rates of 0.01-10s-1.The critical conditions for the onset of dynamic recrystallization (DRX) were determined based on the conventional strain hardening rate curves (dσ/dε versus σ).The progress of DRX was analyzed by constructing a model of volume fraction of DRX based on flow curves.The strain rate sensitivity (SRS) and activation volume V were calculated.The results show that the DRX almost can happen under all deformation conditions even at high Z deformations where dynamic recovery (DRV) is the main softening mechanism.The DRX fraction curves can well predict the DRX behavior.The strain has significant effects on SRS at the strain rates of 0.01s-1 and 10s-1 which are mainly due to off-equilibrium saturation of dislocation storage and annihilation while the effects of the temperature on the SRS are based on the uniformity of microstructure distribution.The formation of "forest" of dislocation is contributed to the low activation volume V*(about 168b3) which is independent of Z values at the initial deformation.The cross-slip due to dislocation piled up beyond the grain boundaries or obstacles is related to the low activation volume under the high Z deformation conditions at high strain (ε=0.6) while the fine DRX grains coarsed is the main reason for the high activation volume at low Z under the same strain conditions.     

Dissolution amounts of nickel, chromium and iron from SUS 304, 316 and 444 stainless steels in sodium chloride solutions

The release of nickel and chromium from stainless steels by sweat, is often responsible for allergic contact dermatitis. The amounts of metal released from stainless steels were in trace amounts, because corrosion resistance was excellent. However, measurement of dissolution amounts is difficult, and if these amounts are not known, the improvement and development of stainless steels with excellent resistance to NaCl solution is difficult. In this work, trace dissolution amounts from the main components of stainless steels which can cause an allergy were investigated. SUS 304, 316 and 444 stainless steels were used in this test. The test solutions used were 0.9 (isotonic sodium chloride solution), 1, 3, 5 and 10 wt% NaCl solutions. Nickel,chromium and iron ions in the test solutions were rapidly determined by stripping voltammetry. The detection limits of Ni(II), Cr(VI) and Fe(III) ions in 1 wt% NaCl solution were 1.0, 0.1 and 0.5 ng cm^-3, respectively, with standard deviations of five tests at 5 ng cm^-3 Ni(II), Cr(VI) and Fe(III) ions, of 6.4%, 1.8% and 2.2%, respectively. Generally, the amounts of the metals dissolved increased in direct proportion to the immersion, in the range 30–60 days for nickel, 30–90 days for chromium and 30–120 days for iron. The dissolution amounts of nickel from SUS 304 and 316 stainless steels increased rapidly over 60 days, while that of chromium increased rapidly over 90 days, in isotonic sodium chloride solution. The ratio of the three dissolved metal ions was not consistent with the composition of the specimens. The ratio of dissolved nickel in SUS 304 and 316 stainless steels was larger than that in the specimen, and dissolved preferentially. The dissolution ratio of chromium and iron in SUS 444 stainless steel approximately agreed with the composition of the specimen. This revised version was published online in November 2006 with corrections to the Cover Date.