• Journal of the Korean Applied Science and Technology
• /
• v.35 no.3
• /
• pp.857-864
• /
• 2018

Demand for developing artificial green pearl that meets the needs of modern people has been increasing. In this paper, eco-friendly inorganic pearlescent pigment was used instead of organic pigment and urethane resin was substituted for nitrocellulose which has been used as main materials in previous preparation method, increasing gloss from 73.4% to 86.7%. Urethane was coated on substrate before finishing with CVD, resulting high gloss of 96%. Colorimeteric analysis shows that a* and b* of CIE value was changed from +37.7 and +24.5 to +31.9 and +14.2 respectively because of CVD finishing, obtaining colorful, high gloss and durable artificial pearl. Quality and toxicity of samples was established by chemical resistance, glossiness, colorimeter, surface roughness, wear resistance, content of heavy-metal, and salt water test.

• Journal of the Korean Applied Science and Technology
• /
• v.32 no.3
• /
• pp.528-535
• /
• 2015

Humanity has tended pursuing beauty. Pearls has been loved by many people for thousands of years as a symbol of wealth and status. Today, Artificial pearl were made using organic pigment due to bright colors and easy coating process. But the new coating technique is required due to low durability, weather resistance and difficulty of luxurious luster expression. This study, nitrocellulose and urethane were used as binder and inorganic pigment were used to expression of colors. Experimental variable of artificial pearl with nitrocellulose and solvent ratio, urethane and curing agent ratio, the amount of pearl number of coating, drying temperature and time, and coating technology was developed. The coated artificial pearl was evaluated with color-difference meter, ultraviolet ray resistance, promotion weathering. Urethane was better than nitrocellulose when compared with weather resistance, acid-alkalinity resistance.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.29 no.4
• /
• pp.334-341
• /
• 1984

Yield response of 30 rice varieties widely grown during the past 70 years in Korea was examined at the six transplanting dates from May 10 to June 29 at the 10 day intervals in 1982. Early japonica varieties grown before 1960s showed the highest yield at the June 9 and 19 transplantings and yields decreased with earlier or later transplantings except the earliest transplanting of May 10. However, yield of recent japonica varieties grown after 1960s was similar among the transplanting dates from May 10 to June 19, but yield was lower at the June 29 transplanting. In the indica/japonica varieties grown after mid- 1970s, yield was highest at the May 10, 20, and 30 transplantings and it decreased with further delay of transplantings largely due to the decreased panicle number, percent ripened grains, and 1,000 grain weight. This may indicate that recently developed varieties may be more adaptable toearly transplanting than older varieties. The number of panicles per hill was variable among the transplanting dates in all varieties, but it decreased as transplanting dates delayed after June 9. In japonica varieties the number of spikelets per panicle, percent ripened grains, and 1,000 grain weight increased as transplanting was delayed. However, in indica/japonica varieties the number of spikelets per panicle was similar among the transplanting dates and percent ripened grains and 1,000 grain weight decreased as transplanting date was delayed after June 9. The percent ripened grains of japonica varieties decreased with increase in the number of spikelets per hill but increased as heading date delayed. However, in indica/japonica varieties the percent ripened grains was not affected by both the number of spikelets per hill and heading date except that of June 29 transplanting of which percent ripened grains was extremely low because of delayed heading although the number of spikelets per hill was low. Grain/Straw ratio was not affected by heading date in japonica varieties, but it decreased significantly as heading date was delayed in indica/japonica varieties.