Processing effects on in-flight particle state and functional coating properties of plasma-sprayed manganese zinc ferrite

Magnetic properties of manganese zinc ferrite (MZF) coatings deposited by atmospheric dc plasma spraying largely depend on zinc and oxygen loss during particle flight. The temperature and velocity of in-flight MZF particles were widely varied by changing plasma spray conditions to examine these chemistry changes and resultant magnetic properties. Zn loss increases with increased particle temperature or decreased particle velocity. Meanwhile, wüstite (FeO) formation, related to the oxygen loss, is more complicated, partly because oxygen, which is lost during flight in the high-temperature zone of the plasma jet, can be recovered at longer spray distances. As a result, the saturation magnetization of MZF coatings decreases and the coercivity increases with increased particle temperature or decreased particle velocity.     

Preliminary spectrum shifter design for intermediate energy nuclear data benchmark experiments with DT neutrons

Integral benchmark experiments with DT neutrons are not always sufficient for nuclear data benchmarking in the MeV region, below 10 MeV. A neutron spectrum shifter, which will be placed between a sample and a DT neutron source, is effective to moderate DT neutrons incident to the sample. In order to estimate effects of the spectrum shifter, the ratio of the contribution of 14 MeV neutrons in the leakage neutron and gamma-ray spectra was calculated with MCNP-4C for an experimental configuration at FNS of JAEA, Japan. The calculations were carried out for a Li₂TiO₃ sample with a Be, D₂O, or ⁷LiD spectrum shifter. It was found out that the Be shifter was superior to others and the Be shifter was effective to decrease the contribution of 14 MeV neutrons especially for secondary gamma-ray spectrum measurements.     

Self-flux synthesis and photoluminescent properties of LiAl5O8

Pure-phase LiAl₅O₈ was selected as an oxide ceramic red phosphor material without dopants (color centers) and was synthesized using a self-flux method. The LiAl₅O₈ was formed by heating a powder mixture consisting of γ-Al₂O₃:Li₂SO₄ = 1:2 (molar ratio) at over 1100 °C for 1 h. Photoluminescence (PL) properties for the synthesized LiAl₅O₈ were investigated. The maximum intensity of the excitation spectrum for the photoluminescent emission of LiAl₅O₈ synthesized was at 274 nm. The peak intensity of the emission spectrum was at a wavelength of 667 nm (red color). The intensity of the peak emission spectrum increased with the heating temperature, i.e., the maximum peak intensity of the red emission spectrum was detected for the LiAl₅O₈ synthesized by heating at 1500 °C for 1 h.     

Detection of relative and uniform motion

We measured the lowest velocity (velocity threshold) for discriminating motion direction in relative and uniform motion stimuli, varying the contrast and the spatial frequency of the stimulus gratings. The results showed significant differences in the effects of contrast and spatial frequency on the threshold, as well as on the absolute threshold level between the two motion conditions, except when the contrast was 1% or lower. Little effect of spatial frequency was found for uniform motion, whereas a bandpass property with a peak at approximately 5 cycles per degree was found for relative motion. It was also found that contrast had little effect on uniform motion, whereas the threshold decreased with increases in contrast up to 85% for relative motion. These differences cannot be attributed to possible differences in eye movements between the relative and the uniform motion conditions, because the spatial-frequency characteristics differed in the two conditions even when the presentation duration was short enough to prevent eye movements. The differences also cannot be attributed to detecting positional changes, because the velocity threshold was not determined by the total distance of the stimulus movements. These results suggest that there are two different motion pathways: one that specializes in relative motion and one that specializes in uniform or global motion. A simulation showed that the difference in the response functions of the two possible pathways accounts for the differences in the spatial-frequency and contrast dependency of the velocity threshold.     

Laser Thomson scattering and optical emission studies of striated PDP micro‐discharge plasmas

Abstract— Properties of a plasma‐display‐panel (PDP) like discharge were examined by emission and laser Thomson scattering (LTS) measurements. Emission measurements were performed using an intensified CCD camera. By varying several external parameters such as the amplitude of the input voltage, gas composition, and pressure, the influence of these parameters on the discharge behavior was studied. Results of emission measurements showed that they were in good agreement with similar emission measurements on real PDP cells. LTS measurements were performed for the striated PDP‐like discharge at a pressure of 100 Torr and the results showed clear modulations in both profiles of electron density and electron temperature.     

Responses of maxillary sensilla styloconica inBombyx mori to glucosides fromOsmunda japonica,a nonhost plant

We isolated glucosides from the royal fern,Osmunda japonica, which elicit a deterrent response in larvae ofBombyx mori. These compounds were absent in taro (Colocasia antiquorum) and castor-oil plant (Ricinus communis) leaves and did not evoke responses of sensory cells in the lateral and medial sensilla styloconica ofSpodoptera litura. This glucoside extract of the royal fern leaves stimulates receptors generally associated with deterrent. It is also possible that this compound may act as a behavioral deterrent, and from actual feeding tests, it is suggested that this compound may prevent feeding in some monophagous insects, such asBombyx mori. The deterrent glucoside possesses a noncyclic aglycon.     

Electrochemical curing of epoxy resins

An electrochemical method has been developed for bonding electrically-conductive adherends. The procedure is based on the electrochemical generation of a curing agent from an otherwise chemically-unreactive precursor mixed with an epoxy resin sandwiched between the bonding members. The one-part epoxy resin is storage stable and cured rapidly on passage of current.     

A torsional transducer through in-plane shearing of paired planar piezoelectric elements

A torsional microtransducer for high-power applications was developed using standard bulk lead zirconium titantate (PZT) placed upon a small rectangular prism made from phosphor bronze, with a tapered conical end serving as a horn and a machined interior to improve the actuator's response. Torsion was obtained from a prototype at the design frequency of 192 kHz as well as over a wide range of frequencies from 136 kHz to 1.02 MHz. Torsional vibration velocities of 335 mm/s at 192 kHz were measured at 27.3 V(RMS) on the 1.5-mm diameter output tip, amounting to 25,600 degree/s vibration velocity along the outer circumference of the tip. At 1.02 MHz, a torsional vibration velocity of 1750 mm/s (134,000 degree/s) at 17.8 V(RMS) was obtained through use of the thickness mode of the PZT elements. Using the design described in this study, high-power torsional transducers with diameters of 5 mm and below are now possible.     

Post-densification behavior of reaction-bonded silicon nitride (RBSN): Effect of various characteristics of RBSN

The effects of the various characteristics of reaction-bonded silicon nitride (RBSN), such as crystalline secondary phases, residual Si, pore size distribution, and agglomerates developed during nitridation on the post-densification behavior, were investigated in detail. A model experiment was carried out to study the effect of crystalline secondary phases in RBSN on the post-densification. The result clearly indicates that the pre-formation of crystalline secondary phases does not influence the sintering of Si₃N₄-powder compacts, which is further demonstrated in the post-densification of RBSN, because the formation of a liquid, including its composition and properties, is dependent on the composition of the system and sintering temperature, but independent of the presence of crystalline secondary phases. In particular, the complete melt of crystalline secondary phases is not related to their melting points and only relies on the composition of the system. The residual Si and pore size distribution in RBSN show no significant effect on the post-densification. Some large pores of 5 m in size could be eliminated by liquid filling and grain growth during post-sintering. The residual Si in RBSN could change into -Si₃N₄ by nitridation of liquid Si and contribute to the weight gain during the early stage of post-sintering. However, it is shown that the agglomerates in RBSN play an important role in the post-densification. The effect of agglomerates on the post-densification strongly depends on their size and amounts in RBSN. Nearly complete densification of RBSN could be reached through lowering of the nitriding temperature or adding Si₃N₄ powder to green bodies, which leads to the formation of more uniform microstructure during nitridation. A mechanism that explains how the agglomerates affect the post-densification of RBSN was discussed based on the theories of liquid phase sintering.     

An aqueous suspension system for phospholipase D-mediated synthesis of PS without toxic organic solvent

Enzymatic synthesis of PS by phospholipase D (PLD)-mediated transphosphatidylation in an aqueous media was investigated. The purpose of this study was to establish a novel synthetic method where no toxic organic solvents were used. An attempt to react soybean lecithin (simply dispersed in an aqueous buffer) with an aqueous solution of l-serine and PLD was unsuccessful, giving only 20% of PS. By contrast, a suspension of lecithin adsorbed on fine powders such as silica was effectively converted into PS in an aqueous solution of l-serine and PLD. After screening various powders for use as the lecithin adsorbent, calcium sulfate was found to be the best with respect to lecithin conversion. In addition, calcium sulfate did not require prior adsorption of lecithin (i.e., the reaction proceeded effectively simply by adding the powder to an aqueous mixture of lecithin, l-serine, and PLD). With this “aqueous suspension system” of calcium sulfate, up to 180 mg/mL lecithin was completely converted, resulting in more than 80% PS in 24 h. The synthesized PS could easily be recovered from the powder by extracting with a mixture of n-hexane, ethanol, and diluted HCl.