• Nuclear Engineering and Technology
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• 제44권5호
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• pp.523-534
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• 2012

The objective of this study was to experimentally investigate the effect of heat curing methods on the temperature history and strength development of slab concrete exposed to $-10^{\circ}C$. The goal was to determine proper heat curing methods for the protection of nuclear power plant structures against early-age frost damage under adverse (cold) conditions. Two types of methods were studied: heat insulation alone and in combination with a heating cable. For heat curing with heat insulation alone, either sawdust or a double layer bubble sheet (2-BS) was applied. For curing with a combination of heat insulation and a heating cable, an embedded heating cable was used with either a sawdust cover, a 2-BS cover, or a quadruple layer bubble sheet (4-BS) cover. Seven different slab specimens with dimensions of $1200{\times}600{\times}200$ mm and a design strength of 27 MPa were fabricated and cured at $-10^{\circ}C$ for 7 d. The application of sawdust and 2-BS allowed the concrete temperature to fall below $0^{\circ}C$ within 40 h after exposure to $-10^{\circ}C$, and then, the temperature dropped to $-10^{\circ}C$ and remained there for 7 d owing to insufficient thermal resistance. However, the combination of a heating cable plus sawdust or 2-BS maintained the concrete temperature around $5^{\circ}C$ for 7 d. Moreover, the combination of the heating cable and 4-BS maintained the concrete temperature around $10^{\circ}C$ for 7 d. This was due to the continuous heat supply from the heating cable and the prevention of heat loss by the 4-BS. For maturity development, which is an index of early-age frost damage, the application of heat insulation materials alone did not allow the concrete to meet the minimum maturity required to protect against early-age frost damage after 7 d, owing to poor thermal resistance. However, the combination of the heating cable and the heat insulating materials allowed the concrete to attain the minimum maturity level after just 3 d. In the case of strength development, the heat insulation materials alone were insufficient to achieve the minimum 7-d strength required to prevent early-age frost damage. However, the combination of a heating cable and heat insulating materials met both the minimum 7-d strength and the 28-d design strength owing to the heat supply and thermal resistance. Therefore, it is believed that by combining a heating cable and 4-BS, concrete exposed to $-10^{\circ}C$ can be effectively protected from early-age frost damage and can attain the required 28-d compressive strength.

• 농업과학연구
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• 제18권1호
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• pp.1-9
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• 1991

본(本) 연구(硏究)는 생장조절물질(生長調節物質) 및 물리적(物理的) 처리(處理)를 통한 포도의 성숙조절기술(成熟調節技術) 확립(確立)을 목적으로 수행되어 다음과 같은 결과(結果)를 얻었다. 1. Anti-gibberellin인 chlormequart 및 paclobutrazol의 verasion 10일전(日前) 처리는 박피(剝皮) 또는 적분처리(摘糞處理)에 관계없이 anthocyanin 함량(含量)을 증가시켰으나 가용성고형물함량(可溶性固形物含量) 및 과실의 숙기(熟期)에는 영향을 미치지 않았다. 환상박피(環狀剝皮)는 성숙(成熟)을 촉진(促進)함은 물론 가용성고형물(可溶性固形物)의 축적(蓄積)을 촉진(促進)하였고 반면에 적엽처리(摘葉處理)는 숙기(熟期) 및 고형물(固形物)의 축적(蓄積)을 현저히 지연(遲延)시켰다. 2. Auxin (2,4-D 및 fenoprop)는 농도(濃度)에 따라 과실의 성숙(成熟)을 20일(日)에서 30일(日)가량 지연(遲延)시켰으며 처리농도(處理濃度)가 50 ppm이상일 경우 과방내(果房內)에서도 과립(果粒)의 성숙(成熟)이 불균일(不均一)하여 정상과립(正常果粒)이 과숙한 후에도 20-30%의 과립(果粒)은 미숙 상태로 남아 있었다. 3. Gibberellin 단용처리(單用處理)는 과실의 성숙(成熟)에 영향하지 않았으나 auxin 가용(加用)의 경우는 auxin 단용에서와 같이 성숙지연(成熟遲延) 및 과립(果粒)의 불균일(不均一)한 성숙현상(成熟現象)이 관찰되었다. 4. Verasio기(期)의 칼슘 가용(加用) ethephon 처리(處理)는 과실의 성숙(成熟)에 영향을 미치지 않았으나 anthocyanin 함량(含量)을 증가시켰다.

• Animal cells and systems
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• 제5권1호
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• pp.37-44
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• 2001

Gonadal development, reproductive cycle, gonad index, meat weight rate, and first sexual maturity of the top shell, Omphalius rusticus were Investigated monthly by histological observations. Specimens were collected from the west coast of Korea during the period from January to December in 1999. O. rusticus is dioecious and oviparous. The gonad is widely situated on the surface of the digestive g1and located in the posterior spiral meat part in the shell. The ovary and the testis were composed of a number of oogenic follicles and several spermatogenic follicles, respectively. Ripe oocytes were approximately 120-130 $\mu$m in diameter. The meat weight rate peaked in June (27.7%), and then rapidly decreased in September (19.5%). Monthly changes in the gonad index in both sexes reached the maximum in June, and then sharply decreased in September. Percentages of first sexual maturity of female and male snails ranging from 9.0 to 9.9 mm in shell heights were 58.3% and 54.5%, respectively, and 100% in those over 11.0 mm in both sexes participated in reproduction. Reproductive cycle of this species can be categorized into five successive stages: in females, early active (October to April), late active (December to June), ripe (April to September), spawning (July to September) and recovery (September to January): in males, early active (November to March), late active (December to June), ripe (April to September), spawning (July to September) and recovery (September to December). Gonadal development, gametogenesis, reproductive cycle, and spawning were closely related to the seawater temperature.

• 한국패류학회지
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• 제22권1호
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• pp.51-61
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• 2006

Oogenesis and the reproductive cycle in female Ruditapes philippinarum were investigated by cytological and histological observations. R. philippinarum is dioecious and oviparous. During vitellogenesis, the Golgi complex, glycogen particles and mitochondria were involved in the formation of lipid droplets and lipid granules in the cytoplasm of the early vitellogenic oocyte. In the late vitellogenic oocyte, cortical granules, the endoplasmic reticulum, and mitochondria were involved in the formation of proteid yolk granules in the cytoplasm. At this time, exogenous lipid granular substance and glycogen particles in the germinal epithelium passed into the oocyte through the microvilli of the vitelline envelope. The spawning period was once a year between early June and early October, and the main spawning occurred between July and August when seawater temperature was approximately $20^{\circ}C$. The reproductive cycle of this species can be categorized into five successive stages: early active stage (January to March), late active stage (February to May), ripe stage (April to August), partially spawned stage (May to October), and spent/inactive stage (August to February). Percentages of female clams at frst sexual maturity of 15.1-20.0 mm in shell length were 52.6% (50% of the rate of group maturity was 17.83 mm in length), and 100% for the clams > 25.1 mm.

• 한국초지조사료학회지
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• 제19권1호
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• pp.89-94
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• 1999

본 시험은 중산간지에서 수확시기 및 품종이 춘파연맥 (Avena sativa L.)의 생육특성, 사초수량 및 사료가치에 미치는 영향을 알아 보고자 축산기술연구소 남원지소 사초시험포장에서 실시되었으며, 수확시기로서 6월 9일과 6월 18일로 주구로 하고 숙기가 다른 Cayuse, Swan, Foothill, Cashel, Martlock, Winjardie 품종을 세구로 하는 분할구 배치 3반복으로 설계하였으며, 결과를 요약하면 다음과 같다. 품종에 따른 출수시작일은 조생종(Swan)의 경우 파종후 50일, 만생 품종(Foothill)은 77일 후에 출수가 시작되었다. 연맥의 건물 함량은 조생품종인 Swan은 6월 8일과 18일 수확시 각각 24.01%, 35.69% 였고 만생종 Foothill은 각각 14.02%, 22.84%였다. 수확시기별 생초수량은 6월 9일과 18일 수확시 Foothill 품종이 각각 ha당 62,666kg, 59,666kg으로 높았고, 조생종 Cashel 품종이 각각 54,222kg, 45,493kg으로 유의적으로 낮았다. 수확시기별 건물수량은 6월 9일 수확시에는 Cashel 품종이 10,169kg으로 높았으나 Martlock 품종이 6,272kg으로 낮았다. 그러나 6월 18일 수확시에는 모든 품종이 10,196~13,043kg으로 증가하였으나 품종간의 유의성은 인정되지 않았다. 조단백질 함량은 모든 품종에서 수확이 늦어짐에 따라 평균 14.0%에서 11.1%로 감소 되었으며, 반면 ADF, NDF 그리고 조섬유 함량은 높아졌다. 또한 in vitro 건물소화율도 수확이 지연됨에 따라 감소하였다. 이상의 연구결과를 종합하면 만생품종 Foothill은 중산간지 (해발 450m)에서 3월 중순에 파종하여 6월 10일과 20일경에 청예로 이용하는 것이 좋은 것으로 생각되며, 건초로 이용시 Martlock 품종을 제외한 모든 품종에서 사초로서 우수함을 알 수 있었다.

• Journal of Animal Science and Technology
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• 제44권2호
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• pp.239-250
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• 2002

본 시험은 사초용 연맥(Avena sativa L.)과 호밀(Secale cereale L.)의 혼파시 호밀 품종의 숙기 및 혼파량이 사초의 생육특성, 수량 및 사료가치에 미치는 영향을 알아보기 위하여 1999년 8월부터 2000년 4월까지 서울대학교 농업생명과학대학 부속 실험목장 사초시험 포장에서 실시되었으며, 호밀 품종의 숙기가 다른 조생 품종인 ‘Koolgrazer'와 만생품종인 'Kodiak'을 주구로 하고 혼파량(T1: 연맥 200kg/ha + 호밀 0kg/ha, T2: 연맥 150kg/ha + 호밀 40kg/ha, T3: 연맥 100kg/ha + 호밀 80kg/ha, T4: 연맥 50kg/ha + 호밀 120kg/ha 및 T5: 연맥 0kg/ha + 호밀 160kg/ha)을 세구로 하는 분할구 시험법으로 3반복 설계 배치하였다. 연맥 호밀 혼파조합에서 가을 수확시 호밀 품종의 숙기는 사초의 조단백질 함량에 영향이 없었으나 호밀의 파종량이 증가함에 따라 조단백질 함량은 13.6%에서 19.3%로 높아졌다(P$<$0.05). 그러나 봄 수확시 만생품종이 15.1%로 10.1%인 조생품종에 비해 높았다(P$<$0.01). 사초의 ADF 함량은 가을 수확시는 호밀 품종의 영향이 없었으나 호밀의 파종량이 증가함에 따라 27.8%에서 20.7%로 감소했다(P$<$0.01). 봄 수확시 만생품종이 28.0%로 조생품종의 35.8%보다 낮았다(P$<$0.01). 또한 NDF 함량과 in vitro 건물소화율도 비슷한 경향을 보였다. 최고의 조사료 건물수량은 ha당 조생종 호밀 품종 80kg과 100kg의 연맥을 혼파한 처리구에서 12,356kg/ha의 건물수량을 나타내었다. 또한 호밀 품종의 숙기와 혼파량간의 유의적인 교효작용효과가 인정되었다(P$<$0.01). 본 시험의 결과를 종합할 때 옥수수의 후작으로 연맥이나 호밀의 재배시 단파보다는 혼파를 하는 것이 건물수량의 증수, 사료품질의 향상에 바람직하며, 혼파량은 ha당 호밀 80kg과 연맥 100kg이 적절하다. 또한 호밀 품종의 숙기는 만생품종보다 조생품종이 사초의 건물수량 증가와 조기수확의 이점이 있다고 생각된다.

• Journal of Preventive Medicine and Public Health
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• 제26권3호
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• pp.347-358
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• 1993

The purpose of this study is to analyze the relationship between the blood pressure level and their sexual maturity and physical growth in the children at puberty. For this purpose, we estimated the blood pressure, physical growth and sexual maturity of the boys of 335 and girls of 373 who are in the middle schools which are located in Kangwha County, Kyungki-Do. Both systolic and diastolic pressure were measured twice. Such physical growth as height, body weight, skin fold thickness, waist circumference, hip circumference and arm circumference were measured. The sexual maturity was estimated according to the classification of Tanner's 5-phase-sexual-maturity : in boys, their pubic hair development phase : in girls, their pubic hair and breast development phase and the menstrual experience. In the phase of the pubic hair development, the boy's sexual maturity was distributed into this; the 1 st 56.4%, the 2nd 29.3%, the 3rd 9.9%, the 4th 4.1% and the 5th 0.3%. While the girls sexual maturity was distributed into this the 1st 20.5%, the 2nd 34.9%, the 3rd 30.6% the 4th 12.6% and the 5th 1.3% in the phase of the pubic hair development, and the 1st 0.8%, the 2nd 13.7%, the 3rd 36.2%, the 4th 18.8% and the 5th 30.5% in the phase of the breast development. This indicated that the girls sexual maturity was higher than those of the boys. The girls menstrual experience rate accounted to the 58.2%. In order to see the relationship between the children's sexual maturity and blood pressure level, we regress blood pressure level on physical growth (i.e., height, BMI) and sexual maturity. Sexual maturity in treates as dummy variables. As the resulf of this analysis, the boys' sexual maturity has nothing to do with the blood pressure either systolic or diastolic. But the girl's systolic pressure was statistically significant ; the 9% of the physical growth, the 5% of the pubic hair development and the 4% of the breast development in sexual maturity was explained. In the girls' diastolic pressure, only their pubic hair development was statistically significant ; the 7% of the physical growth and the 7% of the pubic hair development in the diastolic was explained and the 5% of the physical growth in the diastolic Korotokoff phase IV and the 2% of the pubic hair development in the diastic Korotokoff phase was explained, especially, the girls exprienced menstruation, their systolic and diastolic pressure were significantly high (P<0.01). Conclusively, in the first grade children attending middle schools who are in the early process of the sexual development, the sexual maturity was not related to blood pressure level, on the other hand, the blood pressure level of the girls who are more sexual development than those of the boys' have something to do with sexual maturity and physical growth.

• 한국작물학회지
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• 제68권4호
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• pp.431-437
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• 2023

본 시험은 강원도 북부 지대에서 대한민국 육성 조 품종의 재배모형을 설정하기 위하여 강원도 화천과 인제의 농가 포장에서 조생 품종 '미리메조'와 만생 품종 '황미차조', '삼다차조', 그리고 손가락조 품종 '손가락조 1호'에 대한 파종 시기를 달리하여 출수기 생태 특성을 분석하였다. 1. 강원도 북부지대에서 조 조생종의 출수기는 파종기가 5월 중순(5/15)일 때, 8월 초순으로 출수일수는 약 80일이었으며, 6월 하순(6/20) 파종 시에는 8월 하순으로 출수일수는 약 65일이었다. 2. 만생종은 5월 중순일 때, 8월 중하순(8/18~8/26)으로 약 100일이었으며, 6월 하순(6/20) 파종 시에는 9월 중순(9/8~9/15)으로 약 85일이었다. 3. 출수기 적산온도는 조생종은 파종기 5월 중순의 약 1,700℃에서 6월 중순의 약 1,500℃이었으며, 만생종은 약 2,100℃에서 약 1,900℃의 범위를 보였다. 4. 출수기 일장시간은 조생종은 14.0 h에서 13.2 h로, 만생종은 13.2 h에서 12.5 h의 범위였다. 5. 강원도 북부지대에서 국내 조 품종의 출수 한계기를 8월 하순으로 고려할 때, 출수기 한계 적산온도는 조생종은 약 1,500℃, 만생종은 약 2,000℃로 산정되었다. 6. 출수기간 중 일평균 기온이 증가함에 따라 출수일수는 단축되었으며, 두 특성 간에 부의 상관관계를 보였다. 7. 파종기 지연에 따른 출수기간 중 일평균 기온의 증가는 출수일수 단축 및 적산온도의 감소를 유도하였다.

• International Journal of Concrete Structures and Materials
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• 제10권1호
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• pp.47-60
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• 2016

The objective of this study was to evaluate the capability of different strength-maturity models to account for the effect of the hydration heat on the in-place strength development of high-strength concrete specifically developed for nuclear facility structures under various ambient curing temperatures. To simulate the primary containment-vessel of a nuclear reactor, three 1200-mm-thick wall specimens were prepared and stored under isothermal conditions of approximately $5^{\circ}C$ (cold temperature), $20^{\circ}C$ (reference temperature), and $35^{\circ}C$ (hot temperature). The in situ compressive strengths of the mock-up walls were measured using cores drilled from the walls and compared with strengths estimated from various strength-maturity models considering the internal temperature rise owing to the hydration heat. The test results showed the initial apparent activation energies at the hardening phase were approximately 2 times higher than the apparent activation energies until the final setting. The differences between core strengths and field-cured cylinder strengths became more notable at early ages and with the decrease in the ambient curing temperature. The strength-maturity model proposed by Yang provides better reliability in estimating in situ strength of concrete than that of Kim et al. and Pinto and Schindler.

• 한국건축시공학회지
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• 제2권4호
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• pp.177-182
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• 2002

The purpose of this study is to develope the strength prediction model by Maturity Method. A maturity function is a mathematical expression to account for the combined effects of time and temperature on the strength development of a cementious mixture. The method of equivalent ages is to use Arrhenius equation which indicates the influence of curing temperature on the initial hydration ratio of cement. For the experimental factors of this study, we selected the concrete mixing of W/C ratio 45, 50, 55 and 60% and curing temperature 5, 10, 20 and $30^{\circ}C$. And we compare and evaluate with logistic model that is existing strength prediction model, because we have to verify adaption possibility of new strength prediction model which is proposed by maturity method. As the results, it is found that investigation of the activation energy that are used to calculate equivalent age is necessary, and new strength prediction model was proved to be more accurate in the strength prediction than logistic model in the early age. Moreover, the use of new model was more reasonable because it has low SSE and high decisive factor.