Anionic polymerization of <Emphasis Type="Italic">N</Emphasis>-substituted maleimide with achiral and chiral amines as an initiator

We have investigated anionic polymerization ability of N-substituted maleimides (RMI) with various amines as anionic initiator. As a result, anionic polymerizations of RMI proceed successfully in high polar solvents such as DMF and DMSO. The basicity and structure of amines influenced yields and number average molecular weights of polymers. Furthermore, using various chiral amines as an initiator, polymerizations of RMI were performed to obtain optically active polymers.     

The effect of rare earth elements on the kinetics of the isothermal coarsening of the globular solid phase in semisolid AZ91 alloy produced via SIMA process

In the present study, the effects of rare earth (RE) elements on the microstructure and coarsening kinetics of the solid globular particle in the semisolid slurry of AZ91 magnesium alloy have been studied at 570 °C and 580 °C. The results showed that the coarsening kinetics of the solid globular particles in semisolid slurry of AZ91 alloy satisfies the Ostwald ripening theory. It was shown that the coarsening rate of the solid particles decreases by adding RE elements into AZ91 alloy, specially at 580 °C, which results in the smaller particles size. It was attributed to the solid–liquid interfacial energy reduction due to the addition of RE elements.     

Fabrication of Ferroelectric Photonic Crystals

ABSTRACT

Ferroelectric photonic crystals consisted of a PLZT matrix and 800 nm-pitch air-holes with a diameter of 560 nm were successfully fabricated by the electron-beam-induced patterning process. Hexagonal holes inscribed to the circles with a diameter of 400 nm in a precursor matrix changed to circular holes with a diameter of 560 nm after heat-treatment due to shrinkage of the matrix. The optical properties of CSD-derived PLZT films were also evaluated. The PLZT films showed the refractive index of 2.3 and the Kerr constant of 0.4 × 10^{? 16} m²/V². Therefore, it is expected that an applied voltage of 9.7 V to 1 μ m-thick PLZT photonic crystals induces 1%-decrease in refractive index and 40°-swinging of light with a wavelength of 1.55 μ m.     

Biological stereoselective reduction of 2,6‐ and 3,5‐dimethylcyclohexanones by Glomerella cingulata

The microbial transformations of 2,6‐ and 3,5‐dimethylcyclohexanone were investigated using the plant pathogenic fungus, Glomerella cingulata. With this organism 2,6‐ and 3,5‐dimethylcyclohexanone gave the corresponding 2,6‐ and 3,5‐dimethylcyclohexanol. The metabolites from 2,6‐dimethylcyclohexanone indicated enantioselective reduction by specific optical rotation of the products. The enantiomeric excesses of the microbiological reduction products were determined by ¹H‐NMR spectra of (+)‐MTPA‐esters of the alcohols produced. The reduction of 2,6‐dimethylcyclohexanone was stereospecific, with the (2R,6R)‐ketone being converted to the corresponding (2R,6R)‐(−)‐2,6‐dimethylcyclohexanol; absolute configuration, 70% ee. On the other hand, 3,5‐dimethylcyclohexanone gave the (1α,3α,5α)‐3,5‐dimethylcyclohexanol (74%) and (1α,3β,5β)‐3,5‐dimethylcyclohexanol (26%). © 1999 Society of Chemical Industry     

Measurement of Faraday current in a disk MHD generator

The Faraday current flowing in a circumferential direction in a disk MHD generator was successfully measured using the Rogowski coil method. This fact allowed us to estimate the radial distributions of fluid and electrical properties, such as the gas flow velocity, Hall parameter, and electrical conductivity, from the experimental data. In this paper, a system for measuring the Faraday current measuring system and its calibration method are described in detail. As an example of the experimentally estimated properties, factors governing total pressure reduction along the radial direction are described. © 1998 Scripta Technica, Electr Eng Jpn, 125(4): 19–25, 1998     

DSC study on regioselectively substituted cellulose heteroesters

Six kinds of regioselectively substituted cellulose heteroesters (cellulose propanoate diacetate, cellulose butanoate diacetate, cellulose acetate dipropanoate, cellulose butanoate dipropanoate, cellulose acetate dibutanoate, and cellulose propanoate dibutanoate) and three kinds of cellulose triesters (cellulose triacetate, cellulose tripropanoate, and cellulose tributanoate) were prepared from a microcrystalline cellulose, and their melting points were measured by differential scanning calorimetry. Based on the results of strong correlationship between the melting point and the length of the acyl groups at the secondary hydroxyl groups at C2 and C3 positions, the latter was identified as playing a decisive role in the thermal properties of the cellulose fatty acid heteroesters. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:1511–1515, 1997     

Use of Blended Precursors of Poly(vinylsilane) in Polycarbosilane for Silicon Carbide Fiber Synthesis with Radiation Curing

Blended organosilicon precursors containing 10 or 20% of poly(vinylsilane) (PVS) in polycarbosilane (PCS) were prepared and shaped into fiber form by melt-spinning. The influence of PVS addition on the spinning, radiation-curing, and pyrolysis processes was investigated. The addition of PVS increased the spinability of the precursor melt and increased the oxidation sensitivity of the precursor. By adjusting the precursor compositions and the radiation conditions, highly heat-resistant silicon carbide fibers were obtained.     

Transparent biosensor with micro channel array for optical and electrophysiological detection of luciferin–luciferase reaction

This paper describes a transparent biosensor that was designed to detect both the optical and electrophysiological signals of the luciferin–luciferase reaction. By using microelectromechanical system (MEMS) technologies, we have studied and developed a ‘Micro Channel Array’ (MCA) integrated with suction holes and electrodes as planar patch‐clamp biosensors. A transparent biosensor was developed as an advanced MCA. The developed transparent biosensor employs an SU‐8‐based MCA structure for simultaneous multipoint sensing of optical and electrophysiological signals. In this study, we tested the newly developed biosensor using the mPer1‐luc slice culture, which has circadian rhythms and is a typical example of cells in which a luciferin–luciferase reaction occurs. We could measure the optical and electrophysiological signals of the mPer1‐luc slice culture. Here we describe the experimental results of this study, and describe the design and fabrication of the transparent biosensor with MCA. Copyright © 2007 Institute of Electrical Engineers of Japan© 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Application of water mimics on preparation of eicosapentaenoic and docosahexaenoic acids containing glycerolipids

To obtain enhanced incorporation of highly unsaturated fatty acids and recovery of glycerolipid products, organic solvents with high dielectric constants (water mimics) were substituted for part of the essential water for lipase activation to study their effect on acidolysis and transesterification. In acidolysis/transesterification of fish oil triglycerides and eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), Lipozyme IM-60 with ethylene glycol as a water mimic enhanced the incorporation of EPA and suppressed the hydrolysis of synthesized glycerolipid. On the other hand, transesterification between soy phosphatidylcholine and EPA was enhanced by a water and propylene glycol combination. In a nonaqueous medium that contained appropriate amounts of water and organic solvents (water mimics), Lipozyme IM-60 increased transesterification of EPA into soy phosphatidylcholine. Simultaneously, the recovered glycerolipid products showed decreased hydrolysis of newly synthesized EPA- and DHA-containing glycerolipids.     

Ultrahigh-efficiency power amplifier for space radar applications

This paper describes a broad-band switch mode power amplifier based on the indium phosphide (InP) double heterojunction bipolar transistor (DHBT) technology. The amplifier combines the alternative Class-E mode of operation with a harmonic termination technique that minimizes the insertion loss of matching circuitry to obtain ultrahigh-efficiency operation at X-band. For broad-band Class-E performance, the amplifiers output network employs a transmission line topology to achieve broad-band harmonic terminations while providing the optimal fundamental impedance to shape the output current and voltage waveforms of the device for maximum efficiency performance. As a result, 65% power-added efficiency (PAE) was achieved at 10 GHz. Over the frequency band of 9-11 GHz, the power amplifier achieved 49%-65% PAE, 18-22 dBm of output power, and 8-11 dB gain at 4 V supply. The reported power amplifier achieved what is believed to be the best PAE performance at 10 GHz and the widest bandwidth for a switch-mode design at X-band.