본 실험에서는 낮은 음의 온도계수를 갖는 저온 소결 유전체에 대해 연구하였다. 새로 개발된 재료의 조성은 TiO2(100-X) CuOx(X=1~5wt%)에 미량의 MnO2를 첨가 하였다. CuO를 첨가하지 않은 경우에는 저온 (900˚C) 에서 소결이 진행되지 않았다. CuO 함량이 증가할수록 저온에서 소결이 가능하였으나, 유전율이 낮아지고 유전손실은 증가 하였다. MnO2를 0.6wt% 첨가한 경우 유전율과 Q값이 가장 높게 나타났다.
Concept of primary solidification mode control was adopted to obtain optimal solidification crack resistance, hot ductility, corrosion resistance and toughness for austenitic stainless steel. By controlling primary solidification phase as primary δ and containing no ferrite at room temperature, optimal solidification crack resistance, hot ductility, corrosion resistance and cryogenic toughness could be obtained. The optimum chemical composition of austenitic stainless steel ranges 1.46~1.55(Creq/Nieq ratio) calculated by Schaeffler's equation.
노지재배(露地栽培)한 Lilium elegans 'Connecticut king'의 구근(球根) 굴취시기(掘取時期)를 개화기(開花期)인 6월 5일부터 7월 25일까지 10일(日) 간격(間隔)으로 나누고 잔존엽수(殘存葉數)를 달리해서 일정기간(一定期間) 냉장처리(冷藏處理)(, 0~105일간(日間) 8처리(處理))한 후(後) 촉성재배(促成栽培)한 결과(結果)는 다음과 같다. 1. 맹아율(萌芽率)은 저온처리기간(低溫處理期間)이 길어질수록, 잔존엽수(殘存葉數)가 많을수록 그리고 구근비대기간(球根肥大期間)이 길수록 증가(增加)하는 경향(傾向)이었으며 개화기(開花期)의 미숙구근(未熟球根)도 짧은 저온처리(低溫處理)로 높은 맹아율(萌芽率)을 나타내었다. 개화율(開花率)을 보면 개화기(開花期)의 미숙구근(未熟球根)과 엽(葉) 10매(枚)를 남기고 50일간(日間) 비대(肥大)시킨 구근(球根) 그리고 엽(葉)20매(枚)를 남기고 30일이상(日以上) 비대(肥大)시킨 구근(球根)을 90일간(日間) 저온처리(低溫處理)하였을때, 또 전엽(全葉)을 남기고 30일이상(日以上) 비대(肥大)시킨 구근(球根)을 60일간(日間) 저온처리(低溫處理)했을때 90%이상(以上)의 높은 개화율(開花率)을 나타내었다. 2. 맹아(萌芽) 및 개화(開花)소요일수(日數)는 저온처리일수(低溫處理日數)가 증가(增加)함에 따라 짧아지는 경향(傾向)이었으며 특히 개화(開花)소요일수(日數)에 있에서는 개화기(開花期)의 미숙구근(未熟球根)이 타(他) 처리구(處理區)에 비해 가장 짧았고 정식(定植) 후(後) 100 일 이내에 개화(開花)시킬 수 있었다. 3. 초장(草長), 착화수(着花數), 경경(莖經)등은 공히 개화후(開花後) 구근비대기간(球根肥大期間)이 길수록 증가(增加)하였으며 개화기의 미숙구근(未熟球根)이 가장 저조한 생육(生育)을 나타내었다. 그러나 대구(大球)를 사용(使用)한다면 구근비대기간(球根肥大期間)없이 개화기(開花期)의 미숙구근(未熟球根)을 사용(使用)하여 연내(年內) 절화재배(切花栽培)가 가능할 것으로 판단(判斷)되었다.
저온하(低溫下)의 Growth chamber에서 근유균(根瘤菌)(R-12)를 접종(接種)한 Alfalfa의 수확시기별(收穫時期別) 작물(作物) 각부위(各部位)의 질소시비(窒素施肥)의 효과에 관하여 미국(美國) University of Nevada에서 실험(實驗)한 결과(結果)들을 요약(要略)하면 다음과 같다. 초장(草長), 근장(根長) 및 전장(全長)에 있어서는 질소시비(窒素施肥)의 효과가 나타나지 아니하였으며 작물(作物)의 용적(容積)과 건물수량(乾物
Kadsura coccinea (Lem.) A.C. Smith is used as a medicinal plant and cosmetic material in China and Southeast Asia. To mass-produce Kadsura coccinea seedlings, the effects of gibberellic acid (GA3) and cold stratification treatments on seed germination were investigated. Seed germination rate with GA3 treatment was most effective at concentrations of 250 or 500 mg/L. With respect to mean germination time (MGT), mean daily germination, and T50 (days to reach 50% seed germination), the germination-promoting effect was improved as the concentration of GA3 increased. Stem growth of seedlings was the highest following GA3 treatments of 250 and 500 mg/L, and the growth promoting effect gradually decreased as the concentration of GA3 decreased. Root growth was stimulated at GA3 concentrations of 250–1,000 mg/L. Examination of the effect of stratification treatment for 15, 30 and 60 days at temperatures of 0, 5 and 10℃ on the germination rate revealed that the most stratification treatment temperature was 10℃, and the results improved with longer treatment periods. Altogether, GA3 and stratification treatments improved the seed germination rate, shortened the MGT, improved germination uniformity, and produced healthy seedlings.
지구/행성 내부의 다양한 지질학적 과정을 이해하기 위해서는 고온-고압 환경에서 지구 내부 구성 물질의 특성을 이해하는 것이 필수적이다. 이러한 고압환경을 생성하기 위하여 사용되는 멀티 앤빌 프레스 (multi-anvil press)는 주로 상부맨틀조건의 극한 상황을 재현하는데 사용된다. 멀티 엔빌프레스의 지질학적 사 용을 위한 필수 보정 과정 중 하나는 압력을 생성하기 위한 프레스의 유압과 실제로 시료에 가해지는 압력 사이의 관계인 압력-부하 보정(pressure-load calibration)이다. 압력-부하 보정은 일반적으로 고온-고압 조건에 서는 결정질 물질의 상전이를 이용해서 이루어지는데, 고온에서의 경우와 달리 저온(상온)의 경우 상전이 과 정이 상대적으로 비효율적이므로 압력-부하 보정의 다른 방법론이 요구된다. 본 연구에서는 파이로프 조성 (Mg3Al2Si3O12)의 비정질(비정질 파이로프)의 상온에서의 압축(cold compression)에 따라 발생하는 영구적인 고 밀도화 현상(permanent densification)과 그 기원이 되는 알루미늄 배위 환경의 변화를 고해상도의 27Al MAS 및 3QMAS NMR 분광분석을 통해 정량화하고, 이로부터 압력에 따른 알루미늄의 배위수 변화를 이용해 14/ 8 HT 조립세트(assembly set)와 1,100톤 멀티 앤빌 프레스에 대한 상온에서의 압력-부하 보정을 수행하였다. 본 연구는 NMR분광분석을 이용하여 압력보정을 수행한 최초의 연구결과이며, 비정질 파이로프의 압축-감압에 따른 원자 단위에서의 비가역적 구조 변화는 섭입대 환경과 같은 저온 고압 환경에서 비정질 물질이 겪는 변 화와 그에 따른 지질학적 현상의 이해고양에 실마리를 제공한다.
The purpose of this study is to explore spatio-temporal patterns of extreme low human-sensible temperature (HST) across Mt Halla (1,950m), Korea. To do this, decadal (2011/12-2020/21) averages of daily or hourly windchill index (WCI), which quantifies HST considering the combined effects of low temperature and strong wind, are calculated for 24 weather stations in Mt Halla. Time series of decadal average daily mean show that extreme low HST events with moderate risk level (-27~-10°C) occur in mid-winter (mid-January~early February) around the high mountainous areas of Mt Halla, while such risk does not exist in the low-elevated coastal regions of Jeju Island under subtropical climate. Strong wind around the subalpine climate belt lowers HST by 5°C than air temperature in mid-winter. In extreme cases when the advection of northerly cold wind is intensified by the west high-east low pressure pattern in East Asia, the HST around the peak of Mt Halla can be lowered to high risk level (-39~-28°C) in the early morning times of mid-winter days. These information about mountain bioclimate may help establish mountain extreme climate warning systems, which are needed to protect mountaineers from potential life-threatening accidents caused by extreme low HST events over high mountains such as Mt Halla.
Extreme low temperature has various effects on society. It has negative impacts on health, industry, agriculture, and transportation during winter season. Therefore, extreme low temperature is recognized as main factor that causing traffic accidents. This study analyzed the relationship between low temperature and traffic accidents from 2012 to 2018. This study also compared the differences in vulnerability to low temperature between urban and rural areas. Generalized Additive Model (GAM) and Poisson regression model are used to estimate the thresholds and the level of traffic accidents. The results show that the thresholds tend to be decreased gradually, but the level of traffic accidents are more likely to increase in both urban and rural areas Comparatively, rural areas are more vulnerable to traffic accident caused by drop in temperature than urban areas.
This study was conducted to determine the effect of low temperature and low radiation conditions on the yield and quality of hot pepper at an early growth stage in Korea. In plastic greenhouses, low temperature, low temperature with covered shading treatments were set 17 to 42 days after transplanting. The pepper growing degree days decreased by 5.5% due to the low temperature during the treatment period. Radiation decreased by 74.7% due to the covered shading. After commencing treatments, pepper plant growth decreased with low temperature and low radiation. Analysis of the yield showed that the first harvest was delayed by low radiation. The cumulative yields of 119 days after transplanting were 1,956, 2,171, and 2,018 g/m2 for control, low temperature, and low temperature with low radiation respectively. Capsaicin and dihydrocapsaicin concentrations in pepper fruit decreased with low temperature and low radiation. To investigate the photosynthetic characteristics according to the treatment, the carbon dioxide reaction curve was analyzed using the biochemical model of photosynthesis. Results showed that the maximum photosynthetic rate, Vcmax (maximum carboxylation rate), J (electric transportation rate), and TPU (triose phosphate utilization) decreased at low temperatures; the maximum photosynthetic rate, J, and gm (dark respiration rate) were reduced by shading. These results indicate that low temperature and low radiation can retard early growth, yield, and quality, but these can also be recovered 119 days after planting. Based on the results, the yield and quality of pepper can recover from abiotic stresses with proper cultivation.
In this study, the behavior and ductility characteristics of fiber reinforced concrete was experimentally conducted under high and low temperature conditions. The results showed that the ductility index was increased with temperature increase.
This study was conducted to compensate for the decrease in intensity due to the decrease in temperature and proposed temperature correction strength T28, using the Fractional function model.
저온 감압 조건에서 얻어진 천년초 추출액의 여러 특성을 살펴보고, 이 추출액을 보습제로 활용한 에센스 화장품을 제조하였다. 천년초 추출액은 다른 보습제인 글리세린, 히알루론산 1% 용액에 비해 표면장력(25mN/m)과 접촉각(8 °)이 매우 낮은 값으로 나타났다. 또한 점도도 낮고 끈적임이 거의 없는 특성을 보였다. 천년초 저온감압 추출액은 별도의 계면활성제 첨가 없이도 물에 적은 양의 오일을 유화시킬 수 있었다. 다른 보습제와 달리, 화장품 에센스에서 천년초 추출액의 함량이 높을수록 제형의 끈적임과 점도는 감소하는 결과가 나타났다. 이러한 결과들로부터 천년초 저온 감압 추출액이 수분감과 함께 끈적임이 적은 사용감을 부여하는 천연 보습제로 활용이 가능함을 알 수 있었다.
Background : Ginseng seeds are one of short-lived seeds species which loose their viability easily in the condition of conventional storage. Cryopreservation using liquid nitrogen (LN) has been recommended as a alternative storage for this kind of germplasm short lived or dessiccation-sensitive. This study was performed to find out whether cryopreservation could assure initial viability not only for seeds with high germination rate but also for seeds with low germination rate (in aging process).
Methods and Results : In this work, 3 cultivars of dehisced ginseng seeds were artificial aged in the condition of 40℃, 95% RH during 6 hours with 3 hours-interval. The germination rate of ginseng seeds was decreased to the range of 71 - 94% of initial viability by artificial aging treatment. After 24 hours of vapor-LN exposure on both of artificial aged and non treated seeds as a cryopreservation, germination rate for each cultivar was decreased with the range of 76 - 95% of initial viability. While the decreasing patterns of germination rate for each cultivar showed similar curves between before and after vapor-LN exposure, the aging effects could be slightly little by cryopreservation for 3 cultivars of ginseng seeds.
Conclusion : From the above results, we may suggest that cryopreservation could be recommened for storage tool of dehisced ginseng seeds even with low viability also and expected to make slower seed aging process during preservation period through further study.