An experimental stuty has been made to investigate the supercooling solidification of aqueous binary solutions. NaCl aqueous solutions of 0.0 to 22.4wt% in concentration were utilized as the testing solutions. Temperature variations have been measured during solidification, and the shape of growing ice has been observed under microscope for three cases of cooling direction (sidewise, bottom and top cooling). Solidification processes could be clarified into several steps: 1) rapid growth of a number of needle-shaped crystal, 2) melting of the top of needles, 3) at the same time, growing of thin and dense dendrides of which front is parallel to the cold plate, 4) coalescence of both fronts, and 5) stationary growing of dendrites. By the use of the box-counting method, it has been confirmed that the stationary growing dendritic ice patterns are fractals with a property of self-similarity, and their value of fractal dimension D has been obtained as 1.77 for sidewise growth dendrites, which was almost independent of the concentration c. In contrast to this case, smaller values of D were given in the case of upward growth and decreased with increasing c. These difference of D between the sidewise and the upward growth was attributable to the natural convection due to the gravity.
Quartz cristal units have been used widely for time and frequency contorol applications in many electoronics devices. A frequency of quartz cristal unit is adjusted by depositing a metal (silver or gold), measuring its frequency change in the proccess. For the demand of high-frequency band use and high accuracy of products recently, it has become necessary to measure frequencies by the transmission method with controlling the deposition rate in the frequency adjuster equipment. However, 4ppm frequency decrease of the cristal unit has occurred within 15 minutes after adjusting the frequency in the adjuster that vacuum had been performed by oil diffusion pumps. We found this frequency shift was the result from adsorption by oil moleculars on the fresh depositing surface, not from thermal radiation out of the evaporation source.
Pyrrole monomer substituted in the 3- and 4-positions by cyano and methyl groups (3-Cyano-4-methylpyrrole) was synthesized and it was polymerized by chemical oxidation method, using FeCl3 as oxidizing agents. The obtained polymer was soluble in general organic solvent, but had very low conductivity. We also report a method of preparing conducting copolymers of 3-Cyano-4-Methylpyrrole and pyrrole.
An adhesive agent to use with silicone rubber andacrylic resin was developed. The monomer with a -SiH group which reacts with addition type silicone rubber was synthesized and was copolymerized with MMA. The copolymer solution in toluene as used as an adhesive. Copolymer with different ration of γ-methacryloxy propyl tris (dimethyl siloxy) silane (γ-MPTDMS) and MMA were prepared and the toluene or the other solution of the copolymer was used as an adhesive. The copolymer with a ratio of γ-MPTDMS:MMA=1:9 provided good adhesion between silicone rubber and acrylic resin. The nitromethane solution of γ-MPTDMS/MMA copolymer provided higher bond strength than the other solutions for adhesion between silicone rubber and acrylic resin.