• 한국수소및신에너지학회논문집
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• 제24권2호
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• pp.99-106
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• 2013

The variations of performance and metabolites at an early stage were investigated for the successful start-up technology in continuous fermentative hydrogen production. Unsuccessful start-up was observed when the operation mode was changed from batch to continuous mode after the yield was reached to 0.5 mol $H_2$/mol $hexose_{added}$ by batch mode. $H_2$ production continued till 12 hours accompanied by butyrate production, but did not last with propionate production increase. It was suspected that the failure was due to the regrowth of propionic acid bacteria during batch mode which were inhibited by heat-shock but not completely killed. Thus, successful start-up was tried by early switchover from batch to continuous operation; continuous operation was started after the $H_2$ yield was reached to 0.2 mol $H_2$/mol $hexose_{added}$ by batch mode. Although $H_2$ production rate decreased at an early stage, stable $H_2$ yield of 0.8 mol $H_2$/mol $hexose_{added}$ was achieved after 10 days by lowering down propionate production. And it was also concluded that the reason for $H_2$ production decrease at an early stage was due to alcohol production by self detoxification mechanism against VFAs accumulation.

• 한국초지조사료학회지
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• 제11권1호
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• pp.17-21
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• 1991

A field experiment was carried out to determine the effects of nitrogen(N) fertilization levels(0, 30, 60, 90 and 120 kg/ha) in early spring on the growth, dry matter(DM) yield, seasonal distribution of production and nutritive value of grasses. Additional N after the first, second and third harvest were applied as 60, 60 and 30 kg/ha, equally in 1989. Grass growth and DM yield were significantly increased(p$NO_3$-N concentration was not affected by N level of early spring. It is suggested that, therefore, N application in early spring is essential, and 60 to 90 kg/ha of N application may be desirable in early spring.

• Asian-Australasian Journal of Animal Sciences
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• 제24권4호
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• pp.479-484
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• 2011

The study was conducted on 20 Holstein X Sahiwal cross bred dairy cows, with an average milk production of $2,752{\pm}113.79$ liters in $284{\pm}5.75$ days during a single lactation, that were divided in to two groups of 10 animals. We investigated the oxidative stress and antioxidant status during the transition period in dairy cows. In this study, plasma level of MDA was considered as an indicator of lipid peroxidation and SOD, catalase, GSH and GSHPx as antioxidants. The lipid peroxidation was significantly (p<0.001) higher in cows during early lactation as compared to the cows in advanced pregnancy. A significant positive correlation (r = +0.831, p<0.01) was determined between MDA and catalase in early lactating cows. In early lactating cows, blood glutathione was significantly lower than in advanced pregnant cows. However, early lactating cows showed non-significant negative correlation for all antioxidant enzymes with lipid peroxidation. In conclusion, dairy cows seemed to have more oxidative stress and low antioxidant defense during early lactation or just after parturition than advanced pregnant cows, and this appears to be the reason for their increased susceptibility to production diseases (e.g. mastitis, metritis, retention of fetal membranes etc.) and other health problems.

• Asian-Australasian Journal of Animal Sciences
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• 제15권8호
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• pp.1110-1114
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• 2002

The animal production sector in Jordan is characterized by shortages of locally produced feedstuffs derived from rangeland, forage plants or from human food crops as by products. This is exacerbated by insufficient rainfall, overgrazing, early grazing and high stocking rate. Thus, subject to these constraints, other technological improvements are highly desirable to meet the needs of crop growth and animal production. Alternative adapted technologies are also desirable in order to meet the increased demand for red meat in relation to population growth along with the changes in the price subsidy for feedstuff. The technologies are those, which have been introduced to the animal production sector, obtained in agricultural research stations besides on-farm demonstrations. They include technologies suited for increasing birth and twining rates, synchronizing the mating period, introducing the early weaning method, and animal feed and sheep production. Economic assessments conducted in this study demonstrate promising results of hormonal and nutritional practices in improving production efficiency of Awassi sheep in Jordan. Jordanian published data between 1991 and 1998 were used. The examined practices were: 1) use of PMSG in estrus synchronization in ewes, 2) introduction of early lamb weaning program, 3) supplementation with $AD_3E$ for ewes and 4) the use of agro-industrial feed block as a feed supplement for grazing lambs. Production data were then subjected to partial budgeting for economical evaluation. The use of PMSG outperformed the control groups in fertility and net returns per ewe by US$ 8.36/ewe. The early weaning of lambs increased the net returns by US$ 3.90/lamb. The injection with vitamin $AD_3E$ showed an average additional net return of US$ 5.66/ewe. Feeding agriculture by-product blocks improved weight gain in the feed block groups and resulted in additional net returns of US$ 3.5/lamb. The economic viability and reproductive performance indicators demonstrate that efforts should be undertaken to disseminate these new practices in the development program.

• 한국환경복원기술학회지
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• 제19권2호
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• pp.71-81
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• 2016

This text was experimented and investigated the optimum production time and germination characteristics of seed that collect in Korean Chungnam, in order to offer the basic informations for slope restoration and revegetation using Poaceae plant. Optimum time of seed production was mid-late October of Miscanthus sinensis, Pennisetum alopecuroides, early November to late October of Themeda triandra var. japonica and M. sacchariflorus, and mid November of Phragmites communis. Epiphytic amount of seed full ripe was the most times in mid October of M. sinensis, P. alopecuroides and M. sacchariflorus, early November of T. triandra var. japonica, and mid November of P. communis. Seed rate of maturity was the highest times in early November of M. sinensis, P. alopecuroides and M. sacchariflorus, and mid November of T. triandra var. japonica and P. communis. Germination rate by seed collection time was the highest times in early October of M. sacchariflorus, mid October of T. triandra var. japonica, early November of M. sinensis and mid November of P. communis. Germination days by seed production time was the shortest times in early November of M. sinensis and M. sacchariflorus, mid November of T. triandra var. japonica and P. communis. Optimum temperature of germination was $20{\sim}25^{\circ}C$ in M. sinensis and P. alopecuroides, $25^{\circ}C$ in T. triandra var. japonica, and $25{\sim}30^{\circ}C$ in P. communis.

• 대한조선학회논문집
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• 제54권1호
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• pp.57-62
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• 2017

These days, shipbuilding companies are making an effort to adopt the IT technology in order to improve the production efficiency. One such effort is to utilize a planning and scheduling system to predict the production cost in advance. In this system, assessing the welding material quantity is an important factor. Unfortunately, obtaining the welding material quantity in the early design stage is extremely difficult because the detailed production information, which is essential in deriving the cost associated with welding, is normally available at a later stage. This paper aims at developing a computerized program that produces an index to estimate the welding material quantity in the early design stage. By using only three-dimensional geometric information, the program analyzes the production process and estimates the welding material quantity at any design or production stage when no production information is available. The results can be used for the planning and scheduling system.

• 콘크리트학회논문집
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• 제12권6호
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• pp.51-56
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• 2000

Fly ash used as a cement replacement material increases the long term strength and also improves the durability of concrete and mortar. However, the use of fly ash is a little in spite of great benefit. In order to increase the consumption of fly ash, it has to be used as a cement replacement materials in the production of mortar and concrete, and the reduction of early strength development due to the use of fly ash also has to be diminished. In this study, many chemical compounds which accelerate the early strength was investigated. The $Na_2$$SO_4$, $K_2$$SO_4$, Triethanolamine were selected and applied to the production of mortar. It was found that they enhance the early strength development of mortar(1, 3day) and decrease the amount of $Ca(OH)_2$, and also increase the production of ettringite. According to the results of mercury instruction test, the pores ranged from 0.01 $\mu\textrm{m}$ to 5$\mu\textrm{m}$ were decreased and it was also found in the analysis of X ray and SEM that fly ash increases the amount of ettringite at early ages.

• Asian-Australasian Journal of Animal Sciences
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• 제19권7호
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• pp.970-977
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• 2006

Forage oat (Avena sativa L.) is grown extensively in a double-cropping system on dairy farms. Four oat varieties ('Swan', 'Targa', 'Foothill', and 'Nugene') were evaluated for forage production and forage quality during two growing seasons (spring and autumn) at two locations (central and southern region) in South Korea. The heading stage of four oat varieties was observed during spring, but the autumn season did not produce heading until harvest time except for the 'Swan' variety (early-maturing variety). The heading stage of 'Swan' in both locations was earlier compared to other varieties. The four varieties were resistant to both foliar disease and insects. Lodging resistance was higher during autumn except in 2002 at the central region, and late-maturing varieties ('Foothill' and 'Nugene') have lower lodging resistance. Dry matter (DM) content was significantly different between varieties (p<0.001). Comparing different varieties, 'Swan', an early-maturing variety, was highest in DM content. In DM, total digestible nutrients (TDN) and crude protein (CP) yield, the yield of oat varieties in the southern region was higher than in the central region, and forage yield of the oat varieties in the spring season was higher than during the autumn season. The DM and TDN yield showed significant differences between oat varieties. The CP content of oats grown in the central region (Cheonan) was lower than oats grown in the southern region (Daegu), and the spring season produced oats with lower CP compared to the autumn season. Among the four oat varieties, the CP content of late-maturing varieties was higher than the Swan variety (early-maturing variety). The acid detergent fiber (ADF) and neutral detergent fiber (NDF) contents were higher for the varieties grown in Cheonan and during the spring season. The ADF and NDF contents of late-maturing varieties were lower than the early-maturing variety. TDN and relative feed value (RFV) were higher for the varieties grown in Daegu and during the autumn season. Late-maturing variety had higher TDN and RFV than early-maturing variety. Our study showed differences in forage production and forage quality of oats grown in different locations, seasons and varieties. Forage quality as well as forage production was better in the southern region than in the central region. Forage quality was better during autumn, but forage production was better during spring. Late-maturing variety had better forage quality than the early-maturing variety. Therefore, late-maturing varieties are more suitable for use in the southern region.

• 헤리티지:역사와 과학
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• 제56권3호
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• pp.22-44
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• 2023

청동기시대 전기 생계경제는 문화유형, 환경적 요인 등에 의해 발현될 수 있는 생산방식의 다양성이 충분히 고려되지 않은 채, 농경 수행의 강도를 설명하는데 초점을 맞추어왔다. 이러한 상황은 신석기-청동기시대 이행을 얼마나 단절적으로 또는 연속적으로 이해할 것인가의 문제를 진지하게 고민하지 않는 데서 비롯된 것으로 보인다. 이러한 인식은 생계자원 생산방식의 점진적인 변화를 탐색할 수 있는 경로를 차단해 왔다. 본고에서는 청동기시대 생계자원의 생산방식이 연속·점진적으로 변화되었다는 것을 전제로 하면서, 청동기시대 전기 생산방식에 영향을 주었을 다양한 요소에 따른 생산자원 생산양상을 복원해보고자 하였다. 청동기시대 전기는 문화유형과 생태적소가 다양하게 확인되는바, 특정 시기의 생계자원 생산방식을 복원하는 작업은 단편적인 한두 가지 분석으로는 달성되기가 어렵다. 따라서 생계자원 생산과 관련된 몇 가지 측면을 분리하여 분석·해석하고 종국에는 모두를 종합하는 것이 적절한 방법적 경로가 될 듯하다. 구체적인 연구 방법으로 생계자원 생산과 밀접한 연관을 지니는 문화·환경적 요소-문화유형, 지리·지형적 요소, 토양생산성, 취락규모-에 따라 기능상 분류된 석제 생산도구 구성에 차이가 있는지를 확인하였다. 분석 결과 서울·경기 지역의 청동기시대 전기 생계자원 생산양상에 있어 문화유형과 지리·지형적 입지에 따른 유의미한 차이는 관찰되지 않는 반면, 취락규모와 토양생산성에 따른 생산도구 구성의 차이에서는 통계적으로도 제법 유의한 결과가 도출되었다. 취락규모와 종합생산토양 비율이 증가할수록 수렵·무구, 목가공구, 수확구가 증가하는 반면 어로구의 비율에 있어서는 그 반대의 양상이 관찰되었다. 취락규모나 작물재배의 생산성에 따른 수렵 혹은 농경에 대한 의존도 사이에 상관관계를 기대하게 하나, 취락규모와 토양생산성 비율 간의 회귀분석 결과에서는 상호 유의미한 관계로 해석되지 않았다. 즉, 이는 여러 요인에 따라 생산양상도 상이하며, 어느 단편적인 요소가 특정 취락의 생계자원의 생산방식을 채택하는데 결정적이지 않았다는 것을 보여주는 결과라고 할 수 있다. 따라서 청동기시대 전기 사회에서의 취락을 구성하는 다양한 문화·환경적 요소에 따라 생계자원 생산양상 검토가 필요하다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 추계 학술논문 발표대회
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• pp.71-72
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• 2014

Green Frame is a building frame system to construct a column-beam structure using composite precast concrete members. To reduce the cost of producing precast concrete, in-situ production of members is required. However, when the structural members are produced on site, it needs a large space for production. So, "Just-In-Time" production method should be adopted. For Just-In-Time to be realized, the early strength of members should be ensured for them to be transported. Thus, steam curing to secure the early strength is applied in Green Frame. Yet, a large-scale steam curing system is not possible for in-situ production of precast concrete. A smaller steam curing system is needed. In this regard, the study is aimed to develop a new steam curing method applicable to the in-situ production of precast concrete.