We proposed a monolithic microcavity wavelength conversion device without a polarity-inverted structure. The device consists of a low birefringence paraelectric material and a dielectric material. A fundamental wave intensity is enhanced significantly in the microcavity with two distributed Bragg reflectors, and a second-harmonic wave is efficiently generated in a very short region close to a coherence length. As a first step of this study, we used GaN as a device material, and succeeded in the blue second harmonic generation with a wavelength of 428 nm.

synopsisThe effect of cooking schedule on the molecular weight distribution of an alkyd resin was investigated. At the molar ratio of 1.03/0.43/1.00 for glycerin, lauric acid, and phthalic anhydride, two kinds of alkyd resin were prepared, one by maintaining the reaction temperature a t 170°C for an hour and then raising it up to 230°C (sample I), the other by raising the temperature up to 230°C a t a uniform rate of 33°C per 10 min. (sample 11). Sample I and sample I1 were fractionated into seven or eight fractions by adding n-heptane to 5 wtr% toluene solution a t 30°C. Acid value, hydroxyl value, intrinsic viscosity [q], and the number-average molecular weight an were determined.The result showed that the molecular weight distribution curve obtained from sample I was much narrower than that from sample 11. In addition, a relation was found between were obtained for sample I and sample 11. Based on the differences in the molecular weight distribution curves and in the rate constants for the esterification reactions, glycerinflauric acid and glycerin/phthalic anhydride at 170' and 23OoC, the mechanism of condensation reaction of short oil alkyd resin was discussed.

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