High coercivity in melt-spun SmFe10(Ti,M)2 ribbons (M=V/Cr/Mn/Mo)

Magnetic properties of SmFe₁₀(Ti,M)₂ melt-spun ribbons were studied, where M is V, Cr, Mn, and Mo. The ribbons (M=V/Cr/Mo) quenched at 20 m/s exhibit the high coercivities of 4.2-5.5 kOe. Annealing the ribbons quenched at 40 m/s enhances their coercivities in the range of 5.9-10.0 kOe. In particular, SmFe₁₀ (TiV) and SmFe₁₀(TiCr) ribbons yield coercivities of 10.0 kOe and 7.9 kOe, respectively. This is the highest value among the reported melt-spun ThMn₁₂-type structure ribbons. The importance of Sm atmosphere during annealing in minimizing the Sm evaporation from ribbons is also demonstrated     

Cacao liquor polyphenols reduce oxidative stress without maintaining α-tocopherol levels in rats fed a vitamin E-deficient diet

The effect of crude polyphenols (CLP) from cacao liquor on vitamin F-deficient rats was examined. The CLP fraction contained 49.8% antioxidative polyphenols such as catechins and their oligomers. Supplementation of the vitamin E-deficient diet with CLP for 7 wk did not prevent the decrease in α-tocopherol levels in the liver, kidney, heart, brain, and plasma. The lipid peroxide levels in these tissues increased in the group fed the vitamin F-deficient diet compared with the control group. However, these changes were inhibited in a dose-dependent manner as a result of supplementation of the vitamin E-deficient diet with 0.25, 0.5, or 1.0% CLP. The lipid peroxide levels in plasma increased in the group fed the vitamin E-deficient diet. This change tended to be suppressed as a result of supplementation of the diet with CLP, but the difference was not significant. There was no evidence of absorption and distribution of CLP to the tissues; however, CLP intake resulted in a decrease in oxidative stress without maintaining vitamin E levels in the plasma and the tissues.     

Plasma-polymerized films as moisture barriers for alkali halide optics

The nature of the alkali halide surface is of paramount importance in enabling plasma-polymerized films to act as moisture barriers and protective coatings. We developed an effective in situ surface passivation method that uses the active species formed in a plasma derived from Freon gases to remove surface hydroxide groups with chlorine or fluorine atoms. A plasma-polymerized ethane protective coating deposited onto a passivated NaCl window provided protection from damage by water vapor at 98% relative humidity (RH) for at least 100 h. Furthermore, thin films of a variety of surfactants derived from fatty acids on NaCl and KBr were also useful passivating agents. Lifetimes of up to 10 days were obtained on NaCl at 88% RH. Plasma-polymerized films contained long-lived trapped free radicals which reacted with oxygen when the film was exposed to air. This generated oxygen functionality in the polymer which decreased the hydrophobicity and increased the IR absorption. Methods to eliminate these radicals are discussed.     

Enzyme-immobilized Langmuir-Blodgett film for a biosensor

A lipid-protein monolayer for a biosensor was prepared utilizing a Langmuir- Blodgett technique. The enzyme glucose oxidase was used as the protein. Three types of lipid were chosen to change the surface charge of the polar group. The enzyme was immobilized on the lipid monolayer by adsorption from the subphase solution onto the lipid monolayer on the air/water interface. It was found that the lipid-enzyme interaction was dominated by electrostatic forces, and the characteristics of the film can be controlled by expansion and recompression of the adsorbed monolayer. Finally, a glucose sensor was fabricated by depositing the film onto a hydrogen peroxide electrode.     

Influence of calcium content on the preparation of the high T c (110 K class) Bi-Pb-Sr-Ca-Cu-O thin film

The Bi-Pb-Sr-Ca-Cu-O thin films with various Ca/Sr ratios were prepared by r.f. magnetron sputtering using multi-targets (Bi_0.5Pb_0.50 _x , CaCu_0.750 _x , SrCu_0.75O_x. The high T _c phase (2223 phase) was obtained by firing these films. The film with the highest Ca/Sr ratio (Ca/Sr > 1.0) produced the largest amount of 2223 phase on firing at 850 °C. The highest Ca/Sr ratio (=1.17) film contained 91% volume ratio of 2223 phase compared with the low T _c phase (2212 phase) after 15 h firing. However, the 2223 phase decreased with increasing long-term firing (65 h). The resistance curve of the film with the highest Ca/Sr ratio fired for 65 h showed tailing, until the temperature fell below 20 K, suggesting that this phenomenon was due to the segregation of excess calcium and copper components around the grain, in the amorphous state.     

A voltage source PWM rectifier-inverter with feedforward control of instantaneous power

In general, diode rectifiers with electrolytic capacitors on the dc side have been used as dc power supplies for voltage source inverters. This type of rectifiers, however, causes many problems such as poor power factor and harmonics. Recently, voltage source PWM rectifier-inverters have been studied to provide the following advantages; (1) harmonic-free on both ac sides; (2) unity power factor on the input ac side; (3) power flow of either direction or power regeneration; (4) reduction of the dc capacitor. It is, however, difficult for a conventional one to regulate the capacitor voltage on transient states because of having only a voltage feed-back loop. This paper describes a voltage source PWM rectifier-inverter with feed-forward control of instantaneous power. Based on the pq theory, the instantaneous power which is calculated in the control circuit of the inverter is fed forward to the control circuit of the rectifier. The feed-forward control of instantaneous power makes a great contribution to sufficiently suppress voltage fluctuation of the dc capacitor on transient states. Transient characteristics are discussed and some interesting experimental results of a laboratory model are shown.     

Direct preparation of porous polyethylene filters by radiation polymerization of ethylene

In order to prepare porous, macroscopically homogeneous filters without a separate packing process, ethylene was polymerized by radiation in glass tubes. The bulk density of the polyethylene is approximately proportional to ρ (? M)²I^0.9t², where ρ M is average ethylene density, ? M is average ethylene fugacity, I is radiation dose rate, and t is reaction time. The effect of the bulk density on “treatment capacity” was investigated by experiments where air samples containing 0.1 wt-% iodine vapor were filtered. Treatment capacity is difined as that amount of air per gram of polyethylene which passes through a filter until the polyethylene reaches the break point. The treatment capacity is approximately constant at 9 × 10² cm³/g over the bulk density range from 0.03 to 0.07 g/cm³, and it is lower at the outside of this range. The pressure drop due to the polyethylene filters varies with the 2.7th power of the bulk density when the bulk density is more than 0.03 g/cm³; below 0.03 g/cm³ this exponent increases with decreasing bulk density. Because of both the necessity of high Treatment capacity and that of low pressure drop, the optimum bulk density of polyethylene in the filter is about 0.03 g/cm³.     

Adding versus averaging models revisited: A test of a path-analytic integration model.

Evidence in support of the averaging model of information integration over the adding model is based on the assumption of independence among the items of information being integrated. When nonindependence is introduced in a manner relating to path analysis, the resulting path-analytic integration (PAI) model is shown to account for both crossover interaction and the decelerating set-size effect. The PAI model also makes a prediction contrary to the averaging model: When the set of correlations among 2 items of information and the overall judgment has a negative product, the crossover interaction is predicted to be the opposite of that previously reported. Results supporting the PAI model over the averaging model are obtained in an experiment in which 120 university students were asked to make judgments about the overall attractiveness of a product based on information given about its price and/or quality. (29 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)