Change of the amorphous state by heat treatment below the glass transition temperature

This study was undertaken to elucidate the state of a polymer in the amorphous state through a change of motion of the molecular chain caused by heat treatment below the glass transition temperature. From dielectric measurements of amorphous poly(ethylene terephthalate) heat-treated below T_g, it was found that the average relaxation time, the distribution of relaxation time and the dielectric strength increase with increase of heat treatment. From these results, it was concluded that the amorphous state becomes more random by heat treatment.     

Anodic Dissolution of Uranium Mononitride in Lithium Chloride-Potassium Chloride Eutectic Melt

Uranium-plutonium nitride is a candidate fuel for fast reactors, but its major drawback is ¹⁴C formation from natural nitrogen. One would probably have to use highly ¹⁵N-enriched nitrogen. A pyrochemical process with molten-salt electroreflning has been proposed as a means to increase the nuclear proliferation resistance of the fuel cycle. Molten-salt electroreflning could also be applied to nitride fuels to make possible the recycling of ¹⁵N. The anodic dissolution behavior of UN in LiCI-KCI melt was studied to provide the basis for a feasibility study of electroreflning of irradiated nitride fuels.     

New multicolor and rewritable holographic polymer film for three‐dimensional holographic display

We have developed a new multicolor holographic polymer film. Our holographic polymer film contains 3‐[(2,4,6‐trichloro)azo]‐9H‐carbazole‐9‐ethanol (A‐1) and poly(methyl methacrylate). The holographic polymer film can be recorded with a holographic image without applying an external electric field. The diffraction efficiency was 57% at A‐1 with a 20 wt% of dope ratio. The writable holographic image writing for the holographic polymer film step used the silver halide photographic emulsion master plate 532‐nm laser beam under the nonelectric field. After the copy hologram is formed, our holographic polymer film can be displayed in red and green holographic images. Even though our holographic polymer film is rewritten over 200 times, the diffraction efficiency does not fall. As the holographic polymer film is manufactured using roll‐to‐roll techniques, although still in a laboratory scale in this study, it has a strong possibility of being manufactured in larger sizes with lower cost.     

Tele‐Cocooning: Mobile Texting and Social Scope

The present study examines the tele‐cocooning hypothesis in the context of general trust using a nationally representative survey of Japanese youth. We find that although frequency of texting is positively correlated with general trust, this correlation is spuriously caused by how heavy mobile texters interpret the words “most people” in the general trust measurement. Heavy users assume that “most people” only refers to friends, family, and others going to the same school. When the effect of the “most people” assumption is controlled, the positive association between texting and general trust disappears. Further exploration of the data shows that heavy texting nevertheless has negative implications for social tolerance and social caution, both of which are theoretically proximate to general trust.     

Critical temperature for production of MAG by esterification of different FA with glycerol using <Emphasis Type="Italic">Penicillium camembertii</Emphasis> lipase

Production of MAG by a lipase-catalyzed reaction is known to be effective at low temperature. This phenomenon can be explained by assuming that synthesized MAG are excluded from the reaction system because MAG, which have low m.p., are solidified at low temperatures. Consequently, MAG are efficiently accumulated and do not serve as the precursor of DAG. If this hypothesis is correct, the critical temperature for MAG production, defined as the highest temperature at which DAG synthesis is repressed, should depend on the m.p. of the MAG. Esterification of FFA with glycerol using Candida rugosa, Rhizopus oryzae, and Penicillium camembertii lipases produced MAG efficiently at low temperatures. However, Candida lipase showed very low esterification activity at high temperatures (>20°C), and Rhizopus lipase produced not only MAG but also DAG even at low temperatures. Meanwhile, P. camembertii lipase catalyzed synthesis of MAG only from FFA and glycerol at low temperatures, although the enzyme catalyzed synthesis of DAG from MAG in addition to synthesis of MAG at high temperatures. We thus studied the effect of temperature on esterification of C₁₀−C₁₈ FFA with glycerol using Penicillium lipase as a catalyst and determined the critical temperatures for production of MAG. The critical temperature for production of each MAG showed a linear correlation with m.p. of the MAG, which supported the hypothesis. In addition, because the m.p. of MAG are estimated from that of the constituent FA, the optimal temperature for production of MAG can be predicted from the m.p. of the FFA used as a substrate.     

The effect of sputter etching on the surface characteristics of dyed aramid fabrics

Three kinds of aramid fabrics, Technora (modified p-aramid), Conex (m-aramid) and Kevlar (p-aramid), were subjected to sputter etching and argon low-temperature plasma treatments after dyeing in black with disperse dyes. The depth of shade increased considerably on Technora and Kevlar with the sputter etching treatment, but not on Conex fabrics. Argon low-temperature plasma treatment had virtually no effect on the depth of shade on the aramid fabrics.     

Local disturbances preceding a running crack front in a viscoelastic solid

The local disturbances ahead of a running crack front in a viscoelastic solid were measured through noncontact electro-optical tools. It was observed that the very high local strain rate up to 200/sec exists even in the present quasistatic loading case. It may be concluded that the running crack propagation velocities, not the conventional average strain rates ranging from about 10^?4/sec to 10^?2/sec, govern the local disturbances, as the crack propagation velocities always exceed 200m/sec for both average strain rates, while the local strain rates observed do not show much differences between both average strain rate cases.     

Low-Temperature Synthesis of ZrC Powder by Cyclic Reaction of Mg in ZrO2–Mg–CH4

We investigated the conditions for low-temperature synthesis of ZrC fine powder from ZrO₂–Mg–CH₄. The synthesis utilizes a thermite-type reaction, with Mg as the reducing agent, and a reaction between Mg and CH₄ gas as a carbon source. The Mg/ZrO₂ molar ratio as well as the heating rate were varied. Because C can be continuously fed into the reaction group by the cyclic reaction of Mg through the formation and decomposition of Mg₂C₃ (2Mg + 3CH₄→ Mg₂C₃+ 6H₂→ 2Mg + 3C), a molar ratio of 2.2 for Mg/ZrO₂ was sufficient for the synthesis of single-phase ZrC. ZrC powders were synthesized under the following conditions: Mg/ZrO₂ molar ratio = 2.2, heating rate = 20°C/min, and temperature maintained at 750°C for 30 min. The amount of reaction heat produced in the reduction reaction of ZrO₂ by Mg depended on the Mg/ZrO₂ molar ratio, specifically, the amount of ZrO₂ contained. Moreover, the cyclic reaction of Mg-Mg₂C₃–Mg was influenced by the amount of reaction heat described above and by the heating rate. The ZrC fine powder showed little aggregation and high dispersibility.     

Copolymerization of ethanesultam with 2-methyl-2-oxazoline

Summary This paper describes the so-called No Catalyst Copolymerization between dioxo-1,1-thiazetidine-1,2(Ethanesultam; ESm) and 2-methyl-2-oxazoline. The copolymerization took place without any added initiator to produce copolymers of MeOZO and ESm. The structure of the copolymer was determined by the IR and NMR spectra, elemental analysis, as well as by the result of an alkaline hydrolysis of the copolymer. The reaction scheme of the copolymerization via zwitterion mechanism (Eq 3–5) was proposed.     

Semiconductor Passivation and Insulation Properties for Hydroxyl- and Fluoride-Free ZnO-SiO2-B2O3-Al2O3 Glasses Stabilized by Increased P2O5

F⁻- and OH⁻-free ZnO-B₂O₃-SiO₂-Al₂O₃-P₂O₅ glasses used for semiconductor-device passivation or insulation are investigated with regard to compositional dependencies for thermal expansion, viscosity points, and metal oxide semiconductor (MOS) capacitor properties. The experimental data show that thermal expansion increases, and flow points decrease, when P₂O₅ is substituted for B₂O₃. MOS capacitors passivated by OH⁻- and F⁻-free ZnO-based glasses exhibit normal capacitance-voltage curves.