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        검색결과 1,976

        1401.
        2018.10 서비스 종료(열람 제한)
        The purpose of this study is to compare the strength according as variables of Hwang-Toe activation temperature based on existing references. Compressive strength tests were carried out when the activation temperature was set to 450℃, 600℃, 850℃ and the replacement ration was set to 30%, 50%. As a result, it showed that strengths of specimens overall increased to 850℃. However, strengths of specimens with 50% replacement of Hwang-Toe were significantly reduced at 450℃ and 600℃. In this regard, it is necessary to study the proper quality of activated Hwang-Toe for mortar application in the future.
        1402.
        2018.10 서비스 종료(열람 제한)
        Prediction of compressive strength of concrete by Maturity Method is applied in construction site. However, due to the use of wired type high-priced equipment, economic efficiency and workability are falling. In this study, a newly developed concrete embedded wireless sensor is used to perform a mock-up test. Next, the concrete compressive strength of the Maturity Method is predicted using Saul and Plowman's function as measured temperature data. The predicted concrete strength at the beginning of the age was the actual strength and stiffness, but the error rate was less than 1% at 28th day.
        1403.
        2018.10 서비스 종료(열람 제한)
        This study sought to find a new diagnostic method. The drain hole temperature and the upstream water temperature change were measured for 1 year. The purpose of this study was to analyze the correlation between the temperature of the drain hole and the upstream temperature.
        1404.
        2018.09 KCI 등재 서비스 종료(열람 제한)
        멀티 앤빌 프레스(multi-anvil press)는 일반적으로 5-25 GPa의 압력범위와 ~2,300℃의 온도범위를 구현할 수 있는 고압 기기로, 지구과학에서는 상부맨틀-맨틀전이대까지의 지구 구성물질의 구조를 연구하는 데 도움이 된다. 본 연구에서는 광물의 상전이를 이용한 멀티 앤빌 프레스에 대한 압력- 부하 보정(pressure-load calibration) 과정을 소개하고, 시료실(sample chamber) 내에 존재할 수 있는 온도구배에 대해서 논의하였다. 압력-부하 보정은 14/8 G2, 14/8 step, 14/8 HT 조립세트(assembly set)와 18/12 조립세트에 대해 1,100톤 멀티 앤빌 프레스를 이용하여 수행했다. 초기 물질로 석영, 규회석 구조의 CaGeO₃, 포르스테라이트를 사용했고, 고압상의 동정은 XRD 분석을 통해 수행하였다. 광물의 상전이를 통해 1,200℃에서 시료에 가해지는 압력을 유추할 수 있었으며, α-석영에서 코에사이트로의 상전이는 3.1 GPa, 석류석 구조의 CaGeO₃에서 페로브스카이트 구조의 CaGeO₃로의 상전이는 5.9 GPa, 코에사이트에서 스티쇼바이트로의 상전이는 9.2 GPa, 포르스테라이트에서 와즐리아이트로의 상전이는 13.6 GPa의 압력 확인에 이용했다. XRD 결과로 획득한 압력-부하 보정 곡선은 기존에 보고된 유사한 기기의 압력-부하 보정 곡선에 비해 동일 압력을 구현하기 위해 50톤 가량의 유압이 더 필요한 것으로 확인됐다. 이러한 차이는 시료실의 크기 및 조립세트의 압력 매체(pressure medium)와 이차 앤빌 사이의 마찰력으로부터 기인한 유압 손실에 의한 것으로 생각된다. 또한 본 연구에서는 14/8 HT 조립세트에서의 시료실 내의 온도구배를 확인했다. 특히 열전대(thermocouple)의 위치 변화에 따라 시료실 높이에 평행한 방향으로 약 ~200 ℃/mm에 해당하는 온도구배가 존재한다. 본 연구로부터 구한 멀티 앤빌 프레스의 압력-부하 보정 곡선과 시료실 내의 온도구배 값은 앞으로 맨틀 내에서의 다양한 비정질 및 결정질의 지구물질에 대한 원자 구조의 변화와 그에 따른 물성 변화를 설명하는 데 적용할 수 있다.
        1406.
        2018.08 KCI 등재 서비스 종료(열람 제한)
        국내 일부 시설재배지는 장기간 과도한 양분 투입 등에 의한 염류 집적 현상이 문제가 되어왔으며, 최근 이상기온에 따른 온도장해에 의한 피해도 발생하고 있다. 이러한 현상에 대해 친환경적으로 대처하기 위하여 고염류와 온도 스트레스에 대해 작물에 내성을 증강시키는 미생물을 선발하였다. 국내 토양에서 분리한 1,944균주중 고염류 또는 온도 스트레스 조건에서 세균의 생장과 식물생장촉진 관련 특성(IAA 생성, ACC deaminase 활성, 인산가용화능)을 고려하여 20균주를 1차 선발(전체 균주의 1.03%)하였다. 1차 선발한 20균주 중 토마토 식물검정을 통해 고염류 또는 온도스트레스에 대한 내성을 유도하는 7세균(1차 선발균주의 35%, 전체 균주의 0.36%)을 단계적으로 선발할 수 있었다. 선발된 세균은 16S rRNA 유전자의 염기서열 분석을 통해 모두 Bacillus 속에 속하는 것으로 확인되었다. 이러한 결과로 선발된 7균주는 토마토의 고염류 또는 온도 스트레스에 대한 효과적인 미생물 제제로 활용이 가능한 것을 확인할 수 있었다.
        1407.
        2018.06 KCI 등재 서비스 종료(열람 제한)
        본 연구에서는 원적외선 방사체로 알려져 있는 준 보석 광물인 옥(jade)의 한 종류인 경옥(jadeite) 파우 더를 함유하는 스킨 케어용 O/W 유화 제형을 제조하였다. 경옥 파우더는 화장품 원료로 기 등록된 옥의 다른 한 종류인 연옥(nephrite) 파우더나, 자외선 차단을 목적으로 화장품에 적용되는 이산화티탄 파우더와는 달리, 아무런 분산 첨가제 없이도 수상에서 한달 이상 안정하게 분산이 유지되며 저점도 유화 제형에 5 wt% 이상 균질 유화기로 용이하게 분산이 가능하였다. 이렇게 제조된 경옥 파우더가 2% 함유된 제형을 피부에 도포하고 피부의 표면 온도변화를 적외선 열 영상 분석기로 측정한 결과 동일인의 안면 피부에 경옥 파우더가 함유된 O/W 유화제형을 도포한 부위가 30 min 경과 시 대조군을 도포한 부위의 온도 대비 평균 약 + 1.5 ℃, 최대 + 2 ℃의 온도차이를 나타내는 것을 확인하였다. 이와 같은 현상의 원인을 보다 분명하게 확인하기 위하여 경옥 파우더 자체를 가온한 뒤 복사에 의한 열 방출을 살펴보았고, 전파장대에서의 흡광 분석, 원적외선 방사율 및 표면 원소 분석을 진행한 결과, 이와 같은 피부 온도 변화는 경옥 파우더의 원적외선 방사 효과에 의존하는 것이 아니라 경옥 파우더의 표면에 노출된 원소들과 스킨케어용 화장품에 높은 비율로 포함되어 있는 물 분자와의 수소결합으로 인해 수분 증발을 억제하여 열에너지의 손실을 막기 때문인 것으로 확인되었다. 결론적으로 경옥 파우더는 화장품용 새로운 보습, 보온 소재로서 활용이 가능하며, 흡광 분석결과로 미루어 보아 이산화티탄과 같은 무기 자외선 차단제와 간단히 혼합 병용하여 자외선 및 유해 가시광선 영역의 차단을 증대시키는 보조 소재로도 유용할 것이다.
        1408.
        2018.06 KCI 등재 서비스 종료(열람 제한)
        The purpose of this study is to characterize the synoptic climatic patterns of extreme humansensible temperature (HST) events in Jeju Island, Korea under a subtropical climate condition as well as to examine their teleconnections with the large-scale climate systems. According to the extreme case analysis of the recent 30 years (1988-2017) data sets, the maximum daily average HST in the coastal areas of Jeju Island can rise up to about 40°C in mid-summer and even up to about 48°C during mid-daytime. These extreme HST events occur when the expansion of subtropical Pacific high pressure toward East Asia as well as the poleward shift of the Changma front provides hot and humid conditions over Jeju Island surrounded by seas, particularly in La Niña years with a positive (+) Arctic Oscillation mode. In contrast, the intensified western high and eastern low dipole pressure pattern in mid-winter, which accompanies the downward shear of upper tropospheric cold air toward the southern region of the Korean Peninsula under a negative (-) Arctic Oscillation mode, provides favorable conditions for frequent low HST extreme events. These conditions can lower daily average HST as much as -10°C in the coastal region of Jeju Island, and lower nighttime HST by -25°C on the peak areas of Mt. Halla due to wind chill effects. These findings will be used as a base for establishing prediction and warming systems of extreme HST events on Jeju Island, which is needed to mitigate the damage to the lives of Jeju residents and tourists under climate change.
        1409.
        2018.05 KCI 등재 서비스 종료(열람 제한)
        Fiber-Reinforced Cementitious Composites (FRCCs)는 시멘트 복합체에 혼입한 전도성 섬유로 인해 전기 전도성을 가진다. 이러한 특성은 전기적 응답 계측을 통하여 별도의 센서 설치가 필요 없는 구조물의 균열 모니터링을 가능하게 한다. 하지만 전기적 응답은 균열 발생뿐 만 아니라 온도의 변화에도 민감하게 변화하기 때문에 온도 요인은 전기적 응답 계측을 통한 균열 탐지를 방해하는 요소로 작용할 수 있다. 더욱이 전기적 응답을 측정하기 위한 탐침의 개수가 증가 할수록 원하지 않은 접촉 노이즈가 발생하기 때문에 이 논문에서는 탐침의 개수를 줄이기 위해 자체적인 자가센싱 임피던스 회로를 설계하였다. FRCC의 균열 발생과 온도 변화가 임피던스에 미치는 영향성은 자가센싱 임피던스 회로를 이용해 실험적으로 측정되었으며, 실험 결과, 임피던스 응답은 균열 발생보다 온도 변화에 더 민감하게 변화됨을 알 수 있었다.
        1410.
        2018.05 서비스 종료(열람 제한)
        Background : Prepared Rehmanniae root (PRR) has been used as traditional medicine, and is one of the most important oriental herbal medicines. However, physical characteristics of PRR are not suitable for use in industry. This study was performed to suggest preparation method of PRR powder, and determine the physicochemical characteristics of PRR powder with different pre-freezing temperatures. Methods and Results : Moisture content, powder yield, particle size, bulk density, compressive stress, extraction yield, and 5-HMF content of PRR powders with different pre-freezing temperatures (-20℃, -40℃, -60℃, and -80℃) were analyzed, and correlation among these factors was determined. Powder yield increased and particle size decreased in a pre-freezing temperature-dependent manner from -20℃ to -60℃. Hausner ratio increased from 1.186 to 1.225 with decreasing temperature from -20℃ to -80℃, and compressive stress showed the opposite trend. Extraction yield and 5-HMF content were not significantly different between PRR and powder. Significant correlations were observed among pre-freezing temperature and physical characteristics (yield, particle size, hausner ratio, and compressive stress). Conclusion : These results suggest that pre-freezing temperature was important factors affecting physical characteristics of PRR powder, and the results of this study are industrially applicable to production of PRR powder.
        1411.
        2018.05 서비스 종료(열람 제한)
        Background : Licorice (Glycyrrhiza uralensis F.) is one of the most widely used raw materials for food and pharmaceuticals, and is currently the No. 1 imported medicinal plant in Korea. Efforts to settle licorice cultivation in Korea have been carried out for hundreds of years but have not succeeded, and many people suspect that the reason is due to the inadequate cultivation environment. However, even until recently, most licorice has been procured by wild harvesting, so studies on licorice cultivation technique and cultivation environment have not been conducted much in the world. This experiment was conducted to investigate the germination characteristics of licorice by temperature and salt concentration in order to find the optimal cultivation environment conditions of licorice. Methods and Results : The germination rate of licorice seeds was high 77.5 - 90.5% at 10 - 3 6℃, but it started to drop from 66.5 - 68.0% at 38 - 40℃ and it decreased sharply from 9.0 - 15.0% at 42 - 46℃. No longer germinated at temperatures above 48℃. The average number of days of germination was 12.3 days at 10℃, 5.7 days at 20℃, 3.5 days at 30℃ and 4.1 days at 40℃. The germination start date was 2 to 4 days in the 18℃ - 46℃ range. The average germination rate was the highest at 32℃. The germination time of 40% was 2 - 4 days at 18 - 46℃. The germination of more than 80% took 3 - 5 days at 20 - 40℃, 6 - 8 days at 14 - 1 8℃ and 10 days at 10 - 12℃. Licorice was able to germinate even in the presence of salt. Seed germination rate was 78.5 - 85.5% at 0 - 1% salt concentration and 63% at 1.5% and 18% at 2.0%. In addition, 8.5% seeds germinated successfully even at 3.0% salt concentration. Conclusion : Licorice has been known as a low temperature crop, but germination was possible in a wide range of temperature and salt concentration. Especially, the germination characteristic was higher in the high temperature range of 30 - 36℃, which corresponds to the domestic summer temperature. Therefore, the results of this study are expected to be useful reference for exploring suitable cultivation area in Korea.
        1412.
        2018.05 서비스 종료(열람 제한)
        Background : Platycodon grandiflorum has been used as famous medicinal vegetable and traditional medicine in Korea. Platycodon grandiflorum is used more for vegetable than it is used as a medicine. Proper storage conditons are required for distribution of Platycodon grandiflorum as vegetables. The purpose of this study was to find the appropriate storage temperature. Methods and Results : 2-years old Platycodon grandiflorum cultivated in Herbal Crop Research, RDA Eumseong was used. They were packed with plastic container box of 45 × 70 × 30 ㎝ and then stored at –2℃, 2℃, 5℃, 25℃, humidity 80 - 82%. During the storage, hardness, L a b values, weight loss, decay rate were measured every 30 days as quality indices. During the storage period, L value decreased but a and b values increased and same pattern was observed at all storage temperatures. Hardness decreased and same pattern was also observed at all storage temperature. Under constant humidity conditions, weight loss was larger at higher temperature. The higher the temperature, the larger the deviation at weight loss. There were little decay but 25℃ temperature stored showed that dacay rate was higher with time over. Conclusion : The favorable temperature for storage is –2℃ - 2℃ while maintaining constant humidity.
        1413.
        2018.04 서비스 종료(열람 제한)
        In this study, the expandable shale collected from the same area in Korea is fired to confirm the foamability. The firing uses an electric furnace capable of firing up to 1600 ℃. The shale was classified into three types according to its constituent and apparent characteristics, and each component was analyzed by XRD analysis method. The shale was fired considering the firing temperature and the residence time. As a result of firing, it was found that the firing temperature was different by more than 100 degrees and it was confirmed that the foaming property was increased with increasing temperature
        1414.
        2018.04 서비스 종료(열람 제한)
        Prediction of the compressive strength of the maturity method has been studied by several researchers and has been applied to the construction of concrete structures. In order to apply the maturity method, which is a function related to temperature and time, it is important to measure the accurate temperature inside the concrete during the curing period. The purpose of this study is to verify the performance by analyzing sensitivity, measurement and transmission accuracy by exposing wireless embedded sensor to various curing environment.
        1415.
        2018.04 서비스 종료(열람 제한)
        In this study examined the strength of wall concrete using insulated molds and non-insulated forms by monitoring the strength of the structure using a wireless sensor network by maturity method. It was confirmed that the temperature and compressive strength of the structures are monitored in real time, along with effective strength control.
        1416.
        2018.04 서비스 종료(열람 제한)
        In this study, the partial correlation between the expansion and the vertical displacement excluding the temperature and the correlation between the expansion and vertical displacement and the average temperature of the reinforced truss member was analyzed. The correlation coefficients between temperature and expansion, temperature and vertical displacement were .929 and .874, respectively. The correlation coefficient between vertical displacement and expansion was 0.860 and partial correlation coefficient excluding temperature effect was 0.268.
        1417.
        2018.04 서비스 종료(열람 제한)
        Distributed optical fiber sensors have been developed to detect the occurrence of structural anomalies such as excessive stresses, cracks, and leaks at arbitrary locations in the facility. In this paper, we demonstrate fiber optic OFDR (Optical Frequency Domian Reflectometry) sensor to measure strain and temperature through the sensing optical fiber. A PVC pipe was prepared to show the strain measurement performance with a sensing optical fiber attached on the pipe. Also, a temperature test was performed with a sensing optical fiber located in a temperature chamber. In the results, this sensor can operate to resolve 14.2 micro strain and 1.62 degree temperature at the condition of 5 cm spatial resolution.
        1418.
        2018.03 KCI 등재 서비스 종료(열람 제한)
        The purpose of this article is analyzing the impacts of seawater surface temperature rise on sea mustard yields of Goheung and Wando coast in Korea, with employing a panel data regression model. Our results show that there has been a negative impacts on sea mustard yields as seawater surface temperature continuously has been rising. Especially if the upward trend in seawater surface temperature since 2005 will be maintained in future, sea mustard yield is expected to decrease by 2.6% per year.
        1419.
        2018.02 KCI 등재 서비스 종료(열람 제한)
        Background: Rehmanniae radix preparata (RRP) has been used as a traditional medicine and is one of the most important oriental herbal medicines. However, the physical characteristics of RRP are not suitable for use in industry. The present study was undertaken to determined the preparation method of RRP powder and the physicochemical characteristics of RRP powder by milling under different pre-freezing temperatures. Methods and Results: Moisture content, powder yield, particle size, bulk density, compressive stress, extraction yield, and 5-HMF content of PRR powders by milling with pre-freezing temperatures (−20, −40, −60, and −80℃) were analyzed, and correlation among these factors was determined. Powder yield increased and particle size decreased in a pre-freezing temperature-dependent manner from −20 to −60℃. The Hausner ratio increased from 1.186 to 1.225 with decreasing temperature from −20 to −80℃, whereas compressive stress showed the opposite trend. Extraction yield and 5-HMF content were not significantly different between RRP powder. Significant correlations were observed among pre-freezing temperature and physical characteristics (e.g., yield, particle size, Hausner ratio, and compressive stress). Conclusions: These results suggest that the pre-freezing temperature is an important factor affecting the physical characteristics of PRR powder and applicable to the industrial production of RRP powder
        1420.
        2017.12 KCI 등재 서비스 종료(열람 제한)
        The present study was conducted to investigate the developmental characteristics of Propylea japonica Thunberg (Coleoptera : Coccinellidae), a predator of aphids under laboratory conditions. The development times of the egg and immature stages of Propylea japonica were investigated at ten constant temperatures(15, 17.5, 20, 22.5, 25, 27.5, 30, 32.5, 35 and 38±1℃; 14L:10D; 60±5% RH). Development time was longest at 17.5℃. The developmental periods of P. japonica from the time of egg oviposited to adult emergence was 36.9 days at 17.5℃, and it decreased ash temperature increasing. Threshold temperature of development and degree days of the P. japonica from egg to adult were 11.9℃ and 196.0 respectively. The Briere 2 and Lactin 2 modes were best fitted for all development stages. The distribution of completion of each development stage was explain relatively well that 2-parameter, 3-parameter and Logistic model except egg and pupal stage.