Liatris spicata 구경(球莖)의 휴면도입기(休眠導入期) 및 휴면각성기(休眠覺醒期)를 조사(調査)함과 동시(同時)에 GA처리(處理)에 의(依)한 휴면타파효과(休眠打破效果)를 조사(調査)한 결과(結果)는 다음과 같다. 1. 맹아율(萌芽率), shooting율(率) 및 발근율(發根率)은 8월(月) 30일(日) 이후(以後) 서서히 저하(低下)되어 11월(月) 14일경(日頃) 가장 낮은 경향(傾向)을 보이다가 이후(以後) 서서히 증가(增加)하여 1월(月) 29일(日) 이후(以後)에는 모두 100%로써 매우 양호(良好)하였다. 2. 출아소요일수(出芽所要日數)에 있어서도 11월(月) 14일(日) 무처리구(無處理區)에 있어서 10.1일(日)로써 가장 길었으며 1월(月) 29일(日) 이후(以後)에는 급격(急激)히 단축(短縮)되었다. 3. 맹아(萌芽) 및 shooting 상태(狀態)를 봐서 대구지방(大邱地方)의 노지(露地)에서 Liatris spicata 구경(球莖)의 휴면도입기(休眠導入期)는 9월(月) 하순경(下旬頃), 휴면기(休眠期)는 11월(月) 중순경(中旬頃), 휴면각성기(休眠覺醒期)는 1월(月) 하(下)~2월(月) 초순경(初旬頃)이라고 사료(思料)된다. 4. 구경(球莖)의 휴면타파효과(休眠打破效果)는 GA 200ppm 1시간(時間) 침지처리(浸漬處理)로 효과(效果)가 인정(認定)되었으며 특히(特)히 휴면(休眠)이 깊을수록 그 효과(效果)는 더욱 증가(增加)되는 경향(傾向)을 보였다.

This study was conducted to determine the number of days required to break a plant’s dormancy and promote subsequent crop growth in new varieties of Gomchwi through the 4℃ treatment. Three new varieties of Gomchwi namely, ‘Sammany’, ‘Gommany’, and ‘Damogy’ were observed in this study. The rate of leaf emergence of ‘Sammany’ after 15-day of 4℃ treatment was 100%, while ‘Gommany’, and ‘Damogy’ took 20-days and 10-days, respectively to reach to 97.9% rate of leaf emergence. After 10-days of 4℃ treatment, ‘Damogy’ grew faster than the other varieties. and Harvest time for ‘Damogy’ was on January 18th, after 5-days of 4℃ treatment and yield was observed to be the highest at 15-days of 4℃ treatment. ‘Sammany’ was next with a minimum of 10-days of 4℃ treatment, although 15-days is more preferred for better harvest. ‘Gommany’ on the other hand, did not grow enough for harvest by January 18th, and its harvest time was delayed to January 31st. It needed a minimum of 15-days and preferentially 20-days of 4℃ treatment to grow normally and be ready for harvest. The plant height, leaf length and leaf petiole length appeared to grow better by extending duration of the 4℃ treatment. The number of leaves of ‘Sammany’ and ‘Gommany’ varieties was three leaves for the 5-days treatment which may be due to the incomplete breaking of dormancy. Regarding the yield per plant, ‘Sammany’ yielded 112.3 grams (g) in 15-days treatment, and ‘Gommany’ yielded 106.5 g in 25-days treatment. In the case of ‘Damogy’, it yielded 123.5 g and 183 g in the 10-days and 25-days treatment respectively. It is concluded that ‘Damogy’, ‘Sammany’ and ‘Gommany requires 10, 15, and 20 days of 4℃ treatment to break the plant’s dormancy and promote better plant growth.

선박이 계류삭을 이용하여 부두에 접안하는 경우, 과도한 선박 속력은 계류삭이 절단되는 사고를 야기할 수 있다. 이러한 계류삭의 파단 사고를 방지하기 위해서는 계류삭 파단 방지에 선박의 한계치 접안 속력을 알아야 한다. 본 연구의 목적은 계류삭 파단을 방지하기 위한 선박의 한계치 접안 속력 추정에 있다. 본 연구의 핵심은 선박의 속력을 모르는 경우 선박제원과 계류삭 제원을 이용하여 접안 시 한계치 접근 속력을 추정하는 방법이다. 본 연구에서는 선체저항과 계류삭의 탄성력 등에 관한 이론을 바탕으로 한계치 접안 속력의 추정 방법과 절차를 제안하였다. 135K LNG 선박과 IWRC, 6×36의 강선 계류삭을 대상으로 한계치 접안 속력을 추정한 결과, 추정한 접안 속력으로 접안하는 경우 계류삭이 파단이 되지 않는 것으로 분석되어 제안한 방법이 유효함을 알았다. 본 연구에서 제안한 방법은 실제 선박에서 계류삭 파단을 방지하는데 기여할 수 있을 것으로 기대된다.

The depth of a surface-breaking crack in a concrete slab is characterized by using airborne surface wave transmission measurements. Two air-coupled sensors are used to measure surface waves across surface-breaking cracks with varying depths from 0 mm to 100 mm in a concrete slab (1500 X 1500 X 180 mm3). Resulting transmission coefficient and crack depth relation from a series of experimental studies shows a good agreement with theoretical results previously obtained by the author.

Background: Developing new ginseng cultivars is a significant time-consuming process owing to the three years of growth required for ginseng to flower. To shorten the ginseng breeding process, it is necessary to establish rapid progression through each generation. In this study, we examined it was possible to rapidly break ginseng seed dormancy using gibberellic acid (GA3) treatment and alternating temperature. Methods and Results: Seeds were obtained from local variety. Seeds were treated with either GA3 at a concentration of 100 ㎎/ℓ, constant temperature (−2℃ and 2℃), alternating temperature (2℃ followed by −2℃, followed by 2℃) or a combination GA3 and temperature treatment. Following experimental treatment, seeds were sown into trays and placed in a greenhouse. Low germination rates were observed in seeds that did not receive GA3 treatment, which were similar following 2℃ and −2℃ constant temperature treatment. Germination rates increased in proportion to GA3 and more so when combined with alternating temperature treatment. In additon, stem and leaf lengths of the resulting ginseng plants were increased following GA3 treatment, although no synergistic effect was observed with alternating temperature treatment. Conclusions: These results suggest that a combination GA3 and alternating temperature treatment enhances ginseng seed germination, which can contribute to shortening the time required to progress through a single ginseng generation for breeding.

This study was carried out to develop an effective seed propagation method for Thalictrum rochebrunianum var. grandisepalum (H. Lev.) Nakai by analyzing seed dormancy types and germination characteristics. Seeds were collected between September to October at Gangwon province, and well-selected seeds were used while being dry-stored at 4±1℃. The seed size ranged 4.52 × 1.58 ㎜ and the weight of thousand seeds were 1,603.5 ± 0.02 ㎎. The moisture content was 7.2%. Seeds were achene type, and morphology characters showed an elliptical shape and rough texture, and light brown in color. Moist-chilling treatment was conducted for dormancy breaking because the seeds had an undeveloped embryo of liner type. The embryo had developed during a moist-chilling period, constantly, and fully developed in 10 weeks. Consequently, it seemed to be non-deep complex or intermediate complex type of morphophysiological dormancy, and embryo dormancy was broken by wet-chilling for 10 weeks. After 10 weeks of wet-chilling treatment, seed germination began. Germination percentage was higher in dark condition raher than light condition and recorded the maximum at 25℃ in the dark (16.3%). A pre-soaking treatment with a combined plant growth hormones promoted germination and shortened T50. Specifically, seed germination of 84.5% was achieved by pre-soaking of seeds with a combined solution of 500 ㎎/L GA3 and 10 ㎎/L kinetin for 24 h after a wet-chilling treatment for 10 weeks. Thus the effect of plant growth hormones coupled with chilling temperature on seed breaking dormancy provide asubsequent growth of seedlings for successful plantation.

Background : When ginseng seeds were gathered, the seeds were unripe. To grow immature embryo definitely, special treatment called dehiscence must be performed. Even though dehiscence is completed, most ginseng seeds are on enforced dormancy. The breaking seed dormancy is generally achieved using cold treatment. Also it is reported that gibberellin treatment can replace the treatment. It is very time consuming process in order to develop new ginseng cultivar because ginseng flowers after 3 years of growth. To shorten the ginseng breeding period, it is necessary to establish fast generation progress. Therefore, this study examined the possibility of breaking seed dormancy of ginseng using GA3 treatment and alternating temperature. Methods and Results : Seeds were obtained from local variety fruit which is not inbred. Gibberellin of 100 ppm was treated at seeds for 24 hours. Fixed cold condition was treated on both –2℃ and 2℃. Alternating cold condition was treated on 2℃ and then –2℃, finally 2℃. Fixed and alternating temperature was continued for 15, 30, 45, 60, 90 days that 15 days of alternating temperature is first 2℃ for 5days and then -2℃ for 5days, finally 2℃ for 5days. The other treatment periods such as 30, 45, 60, 90 days mean 10, 15, 20, 30 days respectively. Each of 48 seeds were sowed on tray in greenhouse at 3 replication. Experimental plot was completely randomized. Conclusion : Seeds untreated with GA3 were germinated little and there is no difference between 2℃ and –2℃. Alternating temperature until 60days made no difference with fixed temperature but germination rate increased up to 70.8% when seeds were treated for 90days. Germination of seeds treated with GA3 is much higher than untreated seeds especially combined with alternating temperature.

Lespedeza species are mainly used for wildlife food and cover and for erosion control. The germination of these species can be enhanced after a fire occurrence in forest, which is known as fire-activated seeds to germinate. While the heat treatment could break seed dormancy of Lespedeza, its germination rate was quite low. We investigated that chemical scarification could promote germination of L. tomentosa. Seeds were soaked in 100% sulfuric acid (H2SO4) for 0, 1, 3, 6, 12, 24, 48, 96, 192, and 384 min, and then washed in distilled water for 24 h. Very few seeds were germinated in control (H2SO4 for 0 min). More than 90% of seeds were germinated in H2SO4 for 24, 48, and 92 min. However, some damage was observed in roots and cotyledons of seedling dipped in H2SO4 for a long time. To search the optimal soaking time in H2SO4 without defects, seeds scarified in H2SO4 for 30, 60, 90, 120, 150, 180, and 300 min were sown the commercial soil medium. Seeds treated with H2SO4 for 90 min and 150 min emerged by about 92% and 84%, respectively. Therefore, H2SO4 treatment could break the seed dormancy of Lespedeza species, and especially in case of L. tomentosa the optimal treatment time in sulfuric acid was one to two hours. Germination of L. tomentosa began promptly following the scarification and was completed within about one month, indicating that seeds has no physiological dormancy, just has physical dormancy.

In offshore, various external forces such as wind force, tidal current and impulsive breaking wave force act on offshore wind tower. Among these forces, impulsive breaking wave force is especially more powerful than other forces. Therefore, various studies on impulsive breaking wave forces have been carried out, but the soil reaction are incomplete. In this study, the p-y curve is used to calculate the soil reaction acting on the offshore wind tower when an impulsive breaking wave force occurs by typhoon. The calculation of offshore wind tower against impulsive breaking wave force is applied for the multi-layered soil. The results obtained in this study show that although the same wave height is applied, the soil reaction generated by impulsive breaking wave force is greater than the soil reaction generated by wave force.

Background : Considerable time and effort is required to develop new Panax ginseng varieties. Ginseng breeders have been developing techniques to shorten the breeding cycle to resolve this problem. In this study, we investigated the effects of adding GA3 and alternating temperature (AT, 2℃→ −2℃ → 2℃) on breaking bud dormancy in the varieties (Chungsun and Sunun) of ginseng root. Methods and Results : The GA3 soaking treatment and AT were applied to one year old roots, which greatly accelerated the emergence of new buds. In one year old roots, new buds emerged from the 4th day post transplanting and after breaking dormancy with GA3 and AT treatments. The emergence of new buds was completed within two weeks. The rate of bud emergence for Chungsun was 60% - 98% over 15 - 60 days after the AT and GA3 treatments. The emergence rate of Sunun was 46% - 92%. Normal growth of the ginseng seedling was observed in spite of the early breaking of bud dormancy by combined GA3 and AT treatments. Conclusions : GA3 and AT treatments shortened the dormancy period and facilitated the stable emergence of ginseng seedlings. However, some plants suffered deformities and early sprouting owing to the combined GA3 and AT treatments. Early sprouting was free from dormancy after leaf fall from the of aerial part of the plant.

리프 지형은 전면에 경사가 존재한 후 그 경사가 완만하거나 평탄한 지형이 해안까지 지속되는 형태를 의미한다. 이러한 구조는 외해로부터 입사하는 파랑을 쇄파(braking)시킴으로 그 에너지를 감쇄시켜 해안을 보호하는 역할을 한다. 또한, 대기의 공기를 해저까지 유입시키고, 영양염류의 수직이동을 유도하여 해양생물이 서식하기 좋은 환경을 만들기도 한다. 그러므로 이러한 지형에서 파랑의 변형과 쇄파 양상을 파악하는 것이 중요한 연구 분야이며, 수치모델의 벤치마크 테스트에도 많이 사용되고 있다. 그러나 일정한 경사를 갖는 해안 지형에서의 파랑 변형 및 쇄파 양상에 대한 기존의 연구는 많은 반면, 리프 지형에 대한 연구는 그리 많지 않은 형편이다. 본 연구에서는 전면 경사를 1/40으로 설정한 리프 지형에 대해 수심과 파랑 조건을 변화시키며 파랑 변형 및 쇄파 양상에 대한 2차원 수리모형 실험을 수행하였다. 용량식 파고계를 이용하여 사면 및 리프 지형에서의 파고를 관측하였다. 실험을 통해 얻어진 관측 자료를 기존의 쇄파대 폭(surfzone width)과 쇄파한계파고 지수(breaker height index) 산정식으로 얻어진 결과 값과 비교함으로써 산정식의 적용성을 파악하였다. 또한 파랑조건 별 쇄파 안정파고를 계산하여 효과적인 인공리프(잠제) 폭 설계에 기여할 수 있도록 하고자 하였다.

파티클 기반의 유체 시뮬레이션에서 파티클 들이 경계면에 부딪쳐 쇄파를 일으키는 경우 과도한 움직임으로 인해 자연스러운 흐름을 표현하기 어렵다. 파티클이 이동하는 시간 간격을 세분화하여 선형보간 함으로써 이 문제를 해결할 수 있다. 이렇게 하면 경계면에 모여 압력이 높아진 파티클 들의 가속도 벡터가 부드럽게 변한다. 하지만 보간을 하기위한 최소 샘플수가 높기 때문에 파티클 들이 점성을 가진 액체처럼 뭉치는 문제가 발생한다. 본 연구에서는 이 문제를 해결하기 가중치 보간 방식을 사용한다. 가중치 보간은 파티클의 현재 가속벡터와 이전 가속벡터에 서로 다른 가중치를 주며 차례로 더해 이동벡터를 구한다. 가중치 보간 방식을 쓰면 비슷한 흐름을 표현하는데 필요한 샘플수가 선형 보간 방식보다 적다. 그 결과로 점성을 가진 액체처럼 뭉치는 선형보간 방식의 문제점을 해결할 수 있다.

The depth of a surface-breaking crack in a concrete slab is characterized by using non-contact surface wave transmission measurements. Two air-coupled sensors are used to measure surface waves across surface-breaking cracks with varying depths from 0mm to 100mm in a concrete slab (1500X1500X180mm3). Resulting transmission coefficient and crack depth relation from a series of experimental studies shows a good agreement with theoretical results previously obtained by the author.

쇄파로 인해 발생되는 쇄파유도류가 파랑의 굴절 및 회절에 미치는 영향을 평가하기 위해서는 보다 다양한 실험자료의 구축이 요구된다. 따라서 본 연구에서는 일정 수심상에 타원형 수중 천퇴를 설치한 후 파랑의 전파변형 및 쇄파유도류의 정량적 계측에 대한 수리실험을 수행하였다. 실험에 적용된 천퇴의 제원은 Vincent and Briggs(1989)의 실험과 유사하지만 서로 다른 주기의 파랑을 적용하여 실험자료를 구축하였다. 실험파는 규칙파와 일방향 불규칙파를 적용하였으며, 천퇴 상단에서 쇄파가 발생하는 경우와 발생하지 않는 경우를 포함하였다. 쇄파조건의 실험에 적용된 입사파는 천퇴에 도달하기 전까지는 쇄파가 발생하지 않는 파랑조건이다. 계측은 파봉선과 평행한 방향 뿐만 아니라 파 전파방향에 대해서도 수행하였다.

본 연구에서는 shelf 지형을 대상으로 불규칙파를 적용한 2차원 쇄파변형 수리실험과 Boussinesq형 방정식을 이용한 수치해석을 수행하였다. 유의파고, 유의파봉고, 유의파곡고, 평균수위 및 안정파고와 같은 쇄파특성을 수리실험자료로부터 분석하였고, 실험결과와 Boussinesq형 방정식의 해석결과를 비교하였으며, 두 결과는 비교적 잘 일치하였다. 일정수심상에서의 불규칙파의 쇄파후 안정파고는 수심의 약 0.56배로 분석되었다.

Japonica rice cultivars exhibit high susceptibility to bacterial blight(BB) disease due to genetic vulnerability in Korea. Korean japonica resistant rice cultivars mainly possess one of the genes, Xa1 or Xa3 for BB resistance. These resistance genes are becoming susceptible to K3a, resulting in serious rice yield reduction. This study was carried out to confirm the effect of xa13 gene pyramiding for developing of japonica rice cultivars resistant to BB pathogen breaking down Xa1 or Xa3. IRBB4 conferring Xa4 gene was resistant to K1(HB01013), K2(HB01014), K3(HB01015), and moderately resistant to K3a(HB01009). IRBB5 having xa5 gene was resistant to K1, K2, K3, and K3a. The recessive gene xa13 was resistant to K1 race but susceptible to K2, K3, and K3a. But Xa21 gene is susceptible to predominant K1 race but resistant to other races such as K2, K3, and K3a. Two genes Xa3 and xa13 were susceptible and Xa4 gene was moderate resistant to 24 isolates. xa5 and Xa21 genes were resistant to all isolates including K3a. When xa13 gene combined Xa4, xa5 and Xa21 genes, effect of xa13 gene pyramiding showed higher resistant reaction than that having singe gene out of Xa4, xa5, and Xa21. The order of resistance against 24 isolates breaking down Xa3 gene was IRBB55(xa13+Xa21) > IRBB53 (xa5+xa13) > IRBB51 (Xa4+xa13).