• 한국작물학회지
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• 제61권2호
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• pp.104-112
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• 2016

A double-cropping system with soybean (Glycine max) following the cultivation of potato, garlic, and onion is widely adopted in the southern region of Korea. For this system, marginal dates for planting must be determined for profitable soybean yields, because the decision to plant soybean as a second crop is occasionally delayed by harvest of the first crop and weather conditions. In order to investigate the effect of planting date on soybean yield, three cultivars (early and late maturity) were planted on seven different dates from May 1 to July 30 in both paddy and upland fields across 2012 and 2013. Soybean yields were significantly different among the planting dates and the cultivars; however, the interaction between cultivar and planting date was not significant. Based on linear regression, the maximum yield of soybean was reached with a June 10 planting date, with a sharp decline in yield for crops planted after this date. The results of this study were consistent with those of a previous one that recommends early and mid-June as the optimum planting period. Regardless of soybean ecotype, a reduction in yield of greater than 20% occurred when soybean was planted after mid-July. Frost during soybean growth can reduce yields, and the late maturity cultivars planted on July 30 were damaged by frost before completing maturation and harvest; however, early maturity cultivars were safely harvested. For sufficient time to develop and reach profitable yields, the planting of soybean before mid-July is recommended.

• 한국철도학회논문집
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• 제17권5호
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• pp.365-372
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• 2014

콘크리트 공사에서 공기단축과 시공비 절감을 위하여 가장 핵심적인 기술 중 하나는 온도 제어 양생기술이다. 최근에 마이크로웨이브를 이용한 발열 촉진 양생방법이 개발되었다. 본 연구에서는 개발된 기술을 적용한 콘크리트의 조기 강도발현특성을 실험적으로 고찰하였다. 총 6차에 걸친 대형 Mock-up 실험을 수행하였으며 실험결과를 성숙도이론에 근거하여 해석하였다. 개발된 방법으로 양생된 콘크리트의 압축강도 발현과 성숙도는 로그함수의 관계를 나타내었으며, 일반적인 고온 증기 양생된 콘크리트에 적용되는 등가재령이론으로 강도예측이 가능한 것으로 확인되었다. 개발된 마이크로웨이브 발열거푸집에 의해 동절기에도 하루면 거푸집 탈형을 위한 소요강도를 확보할 수 있는 것으로 나타났다.

• Animal Bioscience
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• 제34권4호
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• pp.584-593
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• 2021

Objective: The objective of this study was to compare fenugreek (FG) with alfalfa (Alf) in ruminal fermentation and methane (CH4) production in vitro. Methods: Whole-plant FG harvested at 11- and 15-wk and Alf harvested at early and mid-bloom maturities, alone or as 50:50 mixture of FG and Alf at the respective maturity, were assessed in a series of 48-h in vitro batch culture incubations. Total fermentation gas and methane gas production, dry matter (DM) disappearance, volatile fatty acids, microbial protein and 16S RNA gene copy numbers of total bacteria and methanogens were determined. Results: Compared to early bloom Alf, FG harvested at 11-wk exhibited higher (p<0.05) in vitro DM and neutral detergent fibre disappearance, but this difference was not observed between the mid-bloom Alf and 15-wk FG. Regardless plant maturity, in vitro ruminal fermentation of FG produced less (p<0.001) CH4 either on DM incubated or on DM disappeared basis than that of Alf during 48-h incubation. In vitro ruminal fermentation of FG yielded similar amount of total volatile fatty acids with higher (p<0.05) propionate percentage as compared to fermentation of Alf irrespective of plant maturity. Microbial protein synthesis was greater (p<0.001) with 11-wk FG than early bloom Alf as substrate and 16S RNA gene copies of total bacteria was higher (p<0.01) with 15-wk FG than mid-bloom Alf as substrate. Compared to mid-bloom Alf, 15-wk FG had lower (p<0.05 to 0.001) amount of 16S RNA methanogen gene copies in the whole culture during 48-h incubation. Conclusion: In comparison to Alf, FG emerges as a high quality forage that can not only improve rumen fermentation in vitro, but can also remarkably mitigate CH4 emissions likely due to being rich in saponins.

• 한국수산과학회지
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• 제8권4호
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• pp.234-241
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• 1975

여수근해산 한전복 Haliotis discus hannai를 재료로 1973년 1월-12월까지 매월 1회씩 24회에 걸쳐 생식선열도지수, 성열도계수, 비만도등의 월변화와 각장 및 전중량의 생식선중량과의 관계, 수온조건 및 자연산모패의 산란유발 결과를 요약하면 다음과 같다. 1. 여수근해산 한전복의 산란가능기간은 5월 하순-7월하순과 9월상순-11월하순이며, 주요산란기는 5월하순-6월중순과 9월하순-11월하순으로 각각 추정되었다. 2. 생식선성열도계수가 극대치를 보인 것은 5월의 44.10과 9월의 49.05였고, 최소치는 1월의 10.09였다. 3. 비만도는 년중 7월이 0.221로 가장 높았으며, 10월에 0.1058로 가장 낮았다. 4. 각장(SL)에 대한 생식선중량(GW)의 비가 년중 가장 높았던 달은 9월이었고, 가장 낮았던 달은 1월로서 이때의 관계식은 9월 : $GW=0.0000003710SL^{3.7860}$ 1월 : $GW=0.000021198SL^{2.8564}$ 각년평균치 : $GW=0.0000005013SL^{4.2273}$ 으로 각각 표시되었다. 5. 전중량(TW)에 대한 생식선중량(GW)의 비가 년중 가장 높았던 달은 9월이었고, 가장 낮았던 달은 1월로서 이때의 관계식은 9 月 : GW=0.1918TW-4.9231 1 月 : GW=0.0992TW-0.1759 주년평균수 : GW=0.1568TW-3.5236으로 표시되었다.

• 한국연초학회지
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• 제4권1호
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• pp.37-42
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• 1982

Korean local and introduced varieties were classified by the cluster analysis of correlation and taxonomic distance based on nineteen growth characters. 1. Thirty six varieties can be classified into three groups(I, II, III) by WVGM (weighted variable group method) 2. Major characters for classifying cultivars were days to flowering, number of leaves, leaf length, stem diameter and width of midrib: the five characters seemed to be useful in monothetic classification. 3. Korean varieties were similar to oriental, and japanese varieties to taiwan. 4. WVGM was more accurate and meaningful than classification by WPGM (weighted paired group method) and reticulate diagram of correlation. 5. Characteristics of each group: Group I closely related to many leaves, late of maturity and broad leaf type, Group II related to medium leaves, late of maturity and narrow leaf type, Croup 19 related to few leaves, early of maturity and medium leaf type respectively.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2016년도 춘계 학술논문 발표대회
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• pp.13-14
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• 2016

This study is aimed to analyze temperature history at each section of mat foundation concrete applying double bubble sheets. The results of the study are as follows. Firstly, the results of measuring the temperature history indicate that the lowest external temperature has been recorded at -5.6℃ for the three-day measurement period. For the central section, the result indicates that the lower, center and upper part have all secured the concrete curing temperature of 18℃ or higher. This results are believed to have resulted from excellent heat insulation performance of double bubble sheets. For the edge section between the edge form and the concrete interface, the temperature has been measured, on average, approximately 12℃ lower than the central section. However, all measured sections have indicated the temperature of 5℃ or higher. Meanwhile, an analysis has been conducted through the estimation equation of compressive strength of maturity during the curing period in order to examine the possibility of early frost damage and the aspect of securing strength. It has been confirmed that the compressive strength is higher than 50°D·D, namely, 5MPa, on the 3rd day of the aging process, which allows early frost damage to be avoided.

• 한국작물학회지
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• 제1권1호
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• pp.3-25
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• 1963

Experiments were carried out to classify the ecotypes and maturity groups of soybean varieties, and to make clear the relationships among these ecotypes, maturity groups and some characteristics in the growing and ripening process of soybean varieties in Korea. Soybean varieties used as the material were 138, 57 varieties collected from Japan, America and Canada and 81 local varieties of Korea. These varieties were grown in the Experimental Farms, College of Agriculture, Seoul National University, Suwon, Korea and Chinju Agricultural College, Kyungsang Namdo, Korea. Seed sowing was conducted at 8 times from April15 to July 29, at 15 day-intervals, in 1962. The classification methods of ecotypes and maturity groups applied in this study, and the results obtained are summarized as follows; 1. Ecotypes were classified from the standpoint of the periods from emergence to flowering, the shortened ratio of days from sowing to flowering by delayed sowing, and the periods from flowering to maturity(as shown in Table A). 2. All varieties wer classified into 10 ecotypes of Ia$_1$, Ib$_1$, IIa$_2$, IIb$_1$, IIb$_2$, IIIb$_1$IIIb$_2$, IIIc$_1$and IIIc$_2$ symbols. Korean local varieties, however, belong to 6 ecotypes of IIb$_1$, IIb$_2$, IIIb$_1$, IIIc$_2$, IIIc$_1$ and IIIc$_2$, respectively(table 1). 3. Durations from sowing to maturity were from 120 to 190 days in April sowing plots of all varieties. From the standpoint of the durations, maturity groups were classified into 9 groups from group I, extreme early, to group IX, extreme late, but our local varieties belong to 5 maturity groups of III, IV, V, VI and VII symbols, respectively(Table 2). 4. Kinds of ecotypes and maturity groups, and the number of soybean varieties belonging to those are as shown in Table B. 5. In this study, it was observed that there were some close relations between these ecotypes and maturity groups (Table 3,4), and among the ecotypes, maturity groups and some other characteristics in the growing and ripening process of the soybean varieties(Table 5). 6. Furthermore, it was also observed that the kinds of ecotypes and maturity groups of recommended varieties in the southern Korean provinces are more numerous than those of the northern provinces in Korea.

• 한국발생생물학회지:발생과생식
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• 제9권2호
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• pp.123-134
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• 2005

암컷 바지락, Ruditapes philippinarum의 난 형성과정 중 생식세포 발달과 난소 성숙 및 군 성숙도를 세포 및 조직학적 관찰에 의해 조사하였다. 바지락은 자웅이체이다. 난황 형성 과정 중 골지복합체, 글리코겐 입자들과 미토콘드리아들은 초기 난황 형성 단계의 난모 세포질 내에서 지방적 및 지방 과립 형성에 관여한다. 후기 난황 형성 단계 난모 세포질 내의 피질 과립, 조면 소포체 및 미토콘드리아들은 세포질 내에서 단백질성 난황 과립의 형성에 관여하였다. 이 시기에 생식상피 내의 외인성 지질 과립상 물질들과 글리코겐 입자들이 난황막의 미세 융모를 통해서 난모 세포질 내로 통과해 들어간다. 산란기는 6월 초에서 10월 초 사이로 연중 한 번이었으며, 주 산란은 해수 수온이 대략 $20^{\circ}C$인 7월과 8월 사이에 일어났다. 본 종의 생식주기는 초기 활성기($1{\sim}3$월), 후기 활성기($2{\sim}5$월), 완숙기($4{\sim}8$월), 부분 산란기($5{\sim}10$월), 퇴화 및 비활성기($8{\sim}2$월)의 연속적인 5단계로 구분되었다. 각장 $15.1{\sim}20.0\;mm$인 암컷 조개의 군 성숙도 비율(%)은 52.6%(군 성숙도 50%는 각장 17.83mm)이었고, 각장 25.1mm 이상인 조개는 100%의 군 성숙도를 보였다.

• 수산해양기술연구
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• 제49권4호
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• pp.449-458
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• 2013

This study investigated purplish Washington clam, Saxidomus purpuratus on its gonadal development, reproductive cycle and shell length (age) at 50% female group maturity from January to December 2011 in Jinhae Bay, Korea. This species is dioecious. The gonad index (GI) began to increase in January, reached the maximum value in May and to decrease in June, reached the minimum value in September then to increase slowly in October again. The reproductive cycle of the clams can be divided into five successive stages: the early active stage (Ea, from February to March), the late active stage (La, from January to March and October to December), the ripe stage (R, from January to May), the spawning stage (S, from June to December) and the degenerative and inactive stage (Ia, from January to February and November to December). The spawning periods were from June to December and the main spawning periods were from July to October. The shell length at 50% female group maturity (SL50) was estimated to be 63.6 mm, which can be converted as sexual maturity age of 2.2 year.

• 한국작물학회지
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• 제54권1호
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• pp.104-118
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• 2009

This study was carried out to classify Korean soybean varieties base on maturity group (MG) and to find character relationships according to planting date for high quality soybean seed production adapted to early season cultivation environment of Miryang. Results of maturity grouping of Korean soybean varieties showed that Keunol (3 cultivars), belonged to Group 0; Seonnok and Danmi in Group II, Shinrok in Group III, Seonyu (17 cultivars), in Group IV, Taekwang (44 cultivars) in Group V, Daewon (25 cultivars) in Group VI, and Kwangdu and Keumdu in Group VII. Agronomic characteristics of 100 soybean varieties were compared based on MG, cultivation year and seeding date. Soybean varieties belonging to the MG $VI{\sim}VII$ showed longer days to flowering and growth period, high lodging density and higher yield. Seed quality analysis revealed that as maturity was delayed, seed weight becomes heavier while seed cracks become abundant. In addition, occurrence of purple seed and phomopsis were higher in MG $0{\sim}III$. Protein content was higher in MG $0{\sim}III$, and isoflavone content was higher as maturity was delayed. On the other hand, lipid content was generally similar across MGs. Correlation analysis of major agronomic characters showed positive relationships between days to flowering and growth days, seed weight and lodging in MG $IV{\sim}V$, seed crack and growth days in MG $0{\sim}III$, seed crack and days to flowering in MG $IV{\sim}V$ and MG $VI{\sim}VII$, seed crack and lodging in MG $IV{\sim}V$ and MG $VI{\sim}VII$, seed crack and seed weight in MG $IV{\sim}V$ and MG $VI{\sim}VII$, purple seed and growth days in MG $IV{\sim}V$, purple seed and seed weight in MG $VI{\sim}VII$, phomopsis and growth days in MG $IV{\sim}V$ and MG $VI{\sim}VII$, and phomopsis and purple seed in MG $IV{\sim}V$ and MG $VI{\sim}VII$. In contrast, a negative relationship was observed between seed weight and lodging in MG $0{\sim}III$. Correlating yield and major characters revealed negative relationships between days to flowering and growth days in MG $0{\sim}III$ and MG $IV{\sim}V$, whereas positive relationships were obtained on MG $VI{\sim}VII$ seeded on April 30. Lodging, seed weight and seed crack were all negatively correlated with yield in the MG $IV{\sim}V$ and MG $VI{\sim}VII$. Soybean cultivars identified as adaptable to early season planting for production of high quality soy curd and fermented soybean paste were Seonyu, Kwangdu, and Soho while those suited for the manufacture of soybean sprouts were Sobaeknanul, Kwangan, Sowon, and Bosuk. Geomjeong 2 chosen as best for mixing with rice.