This study aimed to examine the changes in dry matter yield and growth characteristics of alfalfa (Medicago sativa L.) in response to variations in sowing dates during the autumn season of 2021-22 in a dry paddy field of Chilbo-myeon, Jeongeup-si, Jeollabuk-do. Treatments comprised four sowing dates at 10-day intervals, i.e., October 8, October 18, October 28, and November 8, 2021. The winter survival rate of alfalfa showed a significant difference between different treatments but was at a satisfactory level for all (p<0.05). The winter survival rate for the fourth sowing date, a month later than the first sowing date, was approximately 11.7% lower than that for the first sowing date. The plant height ranged between 82.3–93.1 cm and 60.5–63.7 cm at the first and second harvest, respectively, smaller at the second harvest than at the first harvest. The total dry matter yield of alfalfa was the highest at 13,316 kg/ha for the first sowing date, and the later the sowing date, the lower the dry matter yield. The protein content of alfalfa ranged between 13.6–17.3% in the first harvest, lower than the standard alfalfa protein content of 20% or more. In relative feed value, the first sowing (Oct. 8) was the most significantly higher in the first harvest (p<0.05). These results suggest that the early and mid-October sowing dates are optimum for sowing alfalfa during autumn and result in improved plant growth, dry matter yield, protein content, and winter survival compared to those at later sowing dates. Therefore, dry paddy fields can be safely employed for alfalfa cultivation with sowing dates in early and mid-October during autumn.

은 고분자 전해질은 올레핀/파리핀 혼합물 분리에 매우 효과적인 분리막 재료이다. 이는 고분자 매질속에 녹아 있는 은이온이 올레핀과 선택적, 가역적 반응을 통해 올레핀만을 분리막속으로 통과시키기 때문이다. 그러나 이러한 은 고분자 전해질 분리막은 실제 공정에 응용되기에는 다소 약한 장시간 운전 성능 안정성을 보인다. 즉 분리 성능이 시간이 지남에 따라 점차 감소되는데 이는 은이온이 은 나노입자로 환원되기 때문이다. 따라서 본 연구에서는 poly(vinyl pyrrolidone) (PVP)와 AgBF4로 이루어진 고분자 전해질막의 안정성을 향상시키고자 비이온 계면활성제인 C18H35(OCH2CH2)20OH (Brij98)를 첨가제로 사용하였다. 분리막속에서 은이온의 은 나노입자로의 환원현상을 원자전자 현미경과 자외선 분광학을 이용하여 분석하였다. 그 결과 Brij98이 첨가된 분리막의 경우 은 나노입자의 성장이 늦춰졌으며, 프로판/프로핀렌 선택도가 장시간 유지됨을 알 수 있었다.