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The production of an extracellular polysaccharide, EPS-R, from the marine bacteriumHahella chejuensiswas investigated at various aeration rates in a batch culture. Higher aeration rate resulted in enhanced EPS production and increased the viscosity of the culture broth. At an aeration rate of 1.5 vvm, EPS-R (12.2 g/L) was obtained with a yield (YP/S) of 0.6 from the STN medium after 72h of cultivation. TheH. chejuensiscells changed their rod morphology to a short-rod form in the stationary growth phase.

A marine microorganism, strain 96CJ10356 produced exopolysaccharide, designated as EPS-R. To optimize culture conditions for the production of EPS-R, carbon and nitrogen sources, mineral salts, temperature, and pH were examined. From this study, STN medium for the production of EPS-R was suggested as follows; sucrose 20 g, tryptone 10 g, NaCl 10 g, MgSO45 g, CaCl21 g, KH2PO476 mg, K2HPO483 mg, FeCl25 mg, MnCl21 mg, NaMoO41 mg, and ZnCl21 mg per liter at pH 7.0. About 9.23 g/L of EPS-R was obtained from STN medium after cultivation for 120 h at 25°C in a 5-liter jar fermentor with an aeration rate of 0.17 vvm. Apparent viscosity and flocculation activity of the culture broth were increased with the production of EPS-R and the maximal values were 415 cP and 1400 unit/mL against 0.5% activated carbon, respectively.

AbstractFabrication method of alignment layer was investigated to verify which mechanism is dominant in generating the pretilt angle of LC. The surface energy and the geometrical surface structure were systematically controlled by combining the rubbing and Langmuir-Blodgett(LB) methods. Two layers of LB film were deposited on the top of rubbed polyimide films to remove the surface energy generated by rubbing. In a rubbed polyimide film, polymer chains array in a certain angle which increase with the rubbing strength. The rubbed film with two LB layer showed the contact angle to be the same as the LB film, while the pretilt angle of LB layer on rubbed film was reduced. Therefore it is concluded that the pretilt is more affected by the surface structure of the polyimide alignment layer than the surface energy.

AbstractThe π-A isotherm and transfer characteristics of polymerizable liquid crystals spread at the air-water interface were investigated. The limiting areas of n-[(4-cyano-4′-biphenyl)oxy] alkyl vinyl ether (CN-n-M) homologues series of n = 8, 10, and 11 were about 10, 13, and 17 Å2/molecule respectively, and smaller than the area of hydrophilic cyanobiphenyl group. All the CN-n-M formed apparently stable monolayers and the transferred type of pure CN-11-M monolayer on the hydrophilic surface was Z-type for the first several layers. The monolayer of a mixture with poly(amic acid) salts at 25 mN/m was polymerized by UV-irradiation.

AbstractThe π-A isotherms and transfer characteristics of synthesized, polymerizable liquid crystals spread at the air-water interface were investigated. The liquid crystals mixed with a poly(amic acid) salt were spread, and the mixed monolayers were polymerized by UV-irradiation. The in situpolymerization was monitored by a multi-channel photo detector.